ALBERT

Description: Sustainability, Vol. 10, Pages 2593: Visual Analysis of the Height Ratio between Building and Background Vegetation. Two Rural Cases of Study: Spain and Sweden Sustainability doi: 10.3390/su10082593 Authors: Jacinto Garrido-Velarde María Jesús Montero-Parejo Julio Hernández-Blanco Lorenzo García-Moruno The perception of apparent sizes of buildings in a rural environment depends on the height ratio between the building and its surrounding vegetation, and it is this parameter which is currently used to assess the built landscapes. The impact of a contrasting height is less strong if the building does not exceed the horizon line. For buildings overshooting the skyline, the building’s level of sharpness and number of lines in contrast to the sky determines the impact of the scales, and vegetation in the background helps to reduce impact. The specific objectives of the present study were: (1) finding height–ratio thresholds between building and background vegetation, which may improve the integration of rural buildings in sky-sensitive locations, and; (2) comparing the results in two rural contexts with very different climatic conditions: Spain and Sweden. A survey of eighteen scenarios (nine Spanish and nine Swedish), all digitally modified with different relative height ratios between vegetation and buildings, was performed. The survey was evaluated by the public from both countries. Regardless of the country of origin, integration of the building was good or very good when the vegetation in background did not exceed one half of the height of the construction. These results may be translated to technical criteria for planning assessment.

Description: Sensors, Vol. 18, Pages 2406: Adaptive Robust Unscented Kalman Filter via Fading Factor and Maximum Correntropy Criterion Sensors doi: 10.3390/s18082406 Authors: Zhihong Deng Lijian Yin Baoyu Huo Yuanqing Xia In most practical applications, the tracking process needs to update the data constantly. However, outliers may occur frequently in the process of sensors’ data collection and sending, which affects the performance of the system state estimate. In order to suppress the impact of observation outliers in the process of target tracking, a novel filtering algorithm, namely a robust adaptive unscented Kalman filter, is proposed. The cost function of the proposed filtering algorithm is derived based on fading factor and maximum correntropy criterion. In this paper, the derivations of cost function and fading factor are given in detail, which enables the proposed algorithm to be robust. Finally, the simulation results show that the presented algorithm has good performance, and it improves the robustness of a general unscented Kalman filter and solves the problem of outliers in system.

Description: Sustainability, Vol. 10, Pages 2586: Conserving Tropical Forests: Can Sustainable Livelihoods Outperform Artisanal or Informal Mining? Sustainability doi: 10.3390/su10082586 Authors: Joshua Fisher Poonam Arora Sophia Rhee The viability of conservation efforts, including protected areas and buffer zones, depends on finding ways to make those strategies more attractive and viable for local populations. This paper presents a pilot study utilizing a rapid rural appraisal of livelihoods in the buffer zone of Tambopata National Reserve in Madre de Dios, Peru, threatened by illegal gold mining and logging. We evaluated three predominant economic activities—artisanal gold mining, Brazil nut harvesting, and fish farming—in terms of potential economic returns. The main research question we ask is whether the latter two potentially sustainable land uses can match or exceed the returns from mining. Contrary to popular belief, we find that enhancing value creation at product origin could make existing forest-friendly livelihoods as or more lucrative than extractive ones. This has implications on local conservation policy encouraging implementable strategies incentivizing sustainable livelihoods in tandem with, and in support of, conservation goals.

Description: Sustainability, Vol. 10, Pages 2601: Researcher–Planner Dialogue on Environmental Justice and Its Knowledges—A Means to Encourage Social Learning Towards Sustainability Sustainability doi: 10.3390/su10082601 Authors: Aino Rekola Riikka Paloniemi Societies aiming for a sustainable future need more effective and legitimate planning and decision making practices, in which various actors together find pathways towards a sustainable transition. In this paper, we approach sustainability and environmental justice as epistemological (and ontological) challenges for land-use planning, and empirically analyse how action research could support planners’ social learning and planning towards fair and sustainable development. We analysed qualitatively the evolution of the researcher–planner dialogue while co-designing and developing better methods, means and practices to improve environmental justice in regional scale planning in Kymenlaakso Region, South-East Finland. We found that researcher-planner dialogue developed during cooperation. While in the beginning, social learning related to approaching environmental justice as a fair distribution of power evolved incrementally, later, when dialogue became more focused, communicative and reflective as an outcome of mutual frames and trust, learning occurred in a more transformative way. Such transformative learning concerned recognising youth as a silent group in the planning process and the means to involve their perceptions in planning. In order to support sustainability transformation in the future, we conclude that it is essential to create opportunities for such incremental and transformative social learning through innovative modes of interaction in various contexts.

Description: Sustainability, Vol. 10, Pages 2602: Towards a Joint Local Energy Transition Process in Urban Districts: The GO2Zero Simulation Game Sustainability doi: 10.3390/su10082602 Authors: Geertje Bekebrede Ellen van Bueren Ivo Wenzler The depletion of fossil fuel sources for our energy system and the influence on overall CO2 emissions drive the need to more sustainable energy systems. The transition towards a renewable energy system cannot be seen as a purely technical issue; it is strongly embedded within society. In this study, we analyze the stakeholder complexities of the transition in urban districts and research the use of a simulation game to increase the understanding of the complexity of the transition. Surveys and observations were used to collect data about the learning experiences of playing the game GO2Zero. The results show that participants liked to play the game and they considered the game a valid representation of the system. Further, the participants agree that they obtained a better understanding of the complexity of the residential energy system and experienced a variety of challenges in the transition. Simulation games, like GO2Zero, could become valuable instruments in local energy transition processes as they offer a safe environment for novices and experts to jointly experiment with the challenges in this process. These experiences could support the design of the transition process by helping actors to formulate goals and collaborative strategies for achieving those goals. Future research will focus on the use of this game for experimenting with different strategies and instruments and to analyze their effects.

Description: Sensors, Vol. 18, Pages 2420: Strain Transfer Characteristics of Resistance Strain-Type Transducer Using Elastic-Mechanical Shear Lag Theory Sensors doi: 10.3390/s18082420 Authors: Yongqian Li Zhigang Wang Chi Xiao Yinming Zhao Yaxin Zhu Zili Zhou The strain transfer characteristics of resistance strain gauge are theoretically investigated. A resistance strain-type transducer is modeled to be a four-layer and two-glue (FLTG) structure model, which comprises successively the surface of an elastomer sensitive element, a ground adhesive glue, a film substrate layer, an upper adhesive glue, a sensitive grids layer, and a polymer cover. The FLTG model is studied in elastic–mechanical shear lag theory, and the strain transfer progress in a resistance strain-type transducer is described. The strain transitional zone (STZ) is defined and the strain transfer ratio (STR) of the FLTG structure is formulated. The dependences of the STR and STZ on both the dimensional sizes of the adhesive glue and structural parameters are calculated. The results indicate that the width, thickness and shear modulus of the ground adhesive glue have a greater influence on the STZ ratio. To ensure that the resistance strain gauge has excellent strain transfer performance and low hysteresis, it is recommended that the paste thickness should be strictly controlled, and the STZ ratio should be less than 10%. Moreover, the STR strongly depends on the length and width of the sensitive grids.

Description: Sensors, Vol. 18, Pages 2416: Design and Optimization of a Novel Three-Dimensional Force Sensor with Parallel Structure Sensors doi: 10.3390/s18082416 Authors: Guanyu Huang Dan Zhang Sheng Guo Haibo Qu To measure large external forces exerted on a loading platform, a novel three-dimensional force sensor is developed in this paper. The proposed sensor was designed with a parallel mechanism with three degrees of freedom. Kinematic analysis of this sensor was performed. Due to its structural characteristics, the working principle of the sensor was analyzed using a Jacobian matrix. The sensitivity diversity index and measuring capability were both calculated. The analysis showed that the proposed sensor is more suitable for measuring large forces than existing strain sensors. In addition, compared with existing strain sensors, this sensor is more suitable for measuring forces along the x and y axes. By changing the stiffness coefficients of the springs, the proposed sensor has reconfigurability. This sensor can change its measuring capability to meet different requirements. Next, the mode shapes and natural frequencies of the proposed sensor were performed. Finally, based on these performance indices, the design variables were optimized using a Multi-Objective Genetic Algorithm.

Description: Sensors, Vol. 18, Pages 2415: Cheeses Made from Raw and Pasteurized Cow’s Milk Analysed by an Electronic Nose and an Electronic Tongue Sensors doi: 10.3390/s18082415 Authors: Nuno I. P. Valente Alisa Rudnitskaya João A. B. P. Oliveira M. Teresa S. R. Gomes Elvira M. M. Gaspar Cheese prepared from whole milk, raw and pasteurized, were analysed by an electronic nose based on piezoelectric quartz crystals and an electronic tongue based on potentiometric sensors, immediately after their preparation and along ripening (after 7 and 21 days). Whey was also analysed by the potentiometric electronic tongue. Results obtained by the electronic nose and tongue were found to be complementary, with the electronic nose being more sensitive to differences in the milk and the electronic tongue being more sensitive to milk pasteurization. Electronic tongue was able to distinguish cheeses made from raw and pasteurized milk, both analysing the whey or the curd, with correct classification rate of 96% and 84%, respectively. Besides, the electronic nose was more sensitive than the electronic tongue to the ripening process, with large differences between samples after 7 and 21 days, while the electronic tongue was only sensitive to the initial maturation stages, with large difference between freshly prepared cheese and with seven days of maturation.

Description: Sensors, Vol. 18, Pages 2412: Validation of the Accuracy and Convergence Time of Real Time Kinematic Results Using a Single Galileo Navigation System Sensors doi: 10.3390/s18082412 Authors: Zbigniew Siejka For the last two decades, the American GPS and Russian GLONASS were the basic systems used in global positioning and navigation. In recent years, there has been significant progress in the development of positioning systems. New regional systems have been created, i.e., the Japanese Quasi-Zenith Satellite System (QZSS) and Indian Regional Navigational Satellite System (IRNSS). A plan to build its own regional navigation system named Korean Positioning System (KPS) was announced South Korea on 5 February 2018. Currently, two new global navigation systems are under development: the European Galileo and the Chinese BeiDou. The full operability of both systems by 2020 is planned. The paper deals with a possibility of determination of the user’s position from individual and independent global navigation satellite system (GNSS). The article is a broader concept aimed at independent determination of precise position from individual GPS, GLONASS, BeiDou and Galileo systems. It presents real time positioning results (Real Time Kinematic-RTK) using signals from Galileo satellites only. During the test, 14 Galileo satellites were used and the number of simultaneously observed Galileo satellites varied from five to seven. Real-time measurements were only possible in certain 24-h observation windows. However, their number was completed within 6 days at the end of 2017 and beginning of 2018, so there was possible to infer about the current availability, continuity, convergence time and accuracy of the RTK measurements. In addition, the systematic errors were demonstrated for the Galileo system.

Description: Sustainability, Vol. 10, Pages 2613: An E-Commerce Platform for Industrialized Construction Procurement Based on BIM and Linked Data Sustainability doi: 10.3390/su10082613 Authors: Dandan He Zhongfu Li Chunlin Wu Xin Ning Industrialized construction has raised the requirements of procurement methods used in the construction industry. The rapid development of e-commerce offers efficient and effective solutions, however the large number of participants in the construction industry means that the data involved are complex, and problems arise related to volume, heterogeneity, and fragmentation. Thus, the sector lags behind others in the adoption of e-commerce. In particular, data integration has become a barrier preventing further development. Traditional e-commerce platform, which considered data integration for common product data, cannot meet the requirements of construction product data integration. This study aimed to build an information-integrated e-commerce platform for industrialized construction procurement (ICP) to overcome some of the shortcomings existing platforms. We proposed a platform based on Building Information Modelling (BIM) and linked data, taking an innovative approach to data integration. It uses industrialized construction technology to support product standardization, BIM to support procurement process, and linked data to connect different data sources. The platform was validated using a case study. With the development of an e-commerce ontology, industrialized construction component information was extracted from BIM models and converted to Resource Description Framework (RDF) format. Related information from different data sources was also converted to RDF format, and Simple Protocol and Resource Description Framework Query Language (SPARQL) queries were implemented. The platform provides a solution for the development of e-commerce platform in the construction industry.

Description: Sustainability, Vol. 10, Pages 2614: An Efficient Grid-Based K-Prototypes Algorithm for Sustainable Decision-Making on Spatial Objects Sustainability doi: 10.3390/su10082614 Authors: Hong-Jun Jang Byoungwook Kim Jongwan Kim Soon-Young Jung Data mining plays a critical role in sustainable decision-making. Although the k-prototypes algorithm is one of the best-known algorithms for clustering both numeric and categorical data, clustering a large number of spatial objects with mixed numeric and categorical attributes is still inefficient due to complexity. In this paper, we propose an efficient grid-based k-prototypes algorithm, GK-prototypes, which achieves high performance for clustering spatial objects. The first proposed algorithm utilizes both maximum and minimum distance between cluster centers and a cell, which can reduce unnecessary distance calculation. The second proposed algorithm as an extension of the first proposed algorithm, utilizes spatial dependence; spatial data tends to be similar to objects that are close. Each cell has a bitmap index which stores the categorical values of all objects within the same cell for each attribute. This bitmap index can improve performance if the categorical data is skewed. Experimental results show that the proposed algorithms can achieve better performance than the existing pruning techniques of the k-prototypes algorithm.

Description: Sustainability, Vol. 10, Pages 2609: The Influence of the Backfilling Roadway Driving Sequence on the Rockburst Risk of a Coal Pillar Based on an Energy Density Criterion Sustainability doi: 10.3390/su10082609 Authors: Yi Xue Zhengzheng Cao Feng Du Lin Zhu The rockburst hazard has always been an important issue affecting the safety production of coal mines in China. The unreasonable sequencing of roadway driving can lead to the dynamic instability of coal pillars, which subsequently causes rockburst accidents in roadway backfilling mining engineering and poses a serious threat to the safety of the mines. Roadway backfilling mining technology is an effective approach with which to mine corner residual coal resources under buildings, railways, and rivers. An energy density criterion is established and programmed with FISH language using numerical analysis software for the rockburst risk evaluation of coal pillars. On this basis, a numerical simulation model is established based on four scheme types, namely, the sequential mining, one-roadway interval mining, two-roadway interval mining, and three-roadway interval mining schemes. The influence of the backfilling roadway driving sequence on coal pillar stability is investigated, and the change law of vertical stress and energy density factor of coal pillars in different driving sequences in roadway backfilling mining technology are analyzed. According to the research results, the maximum energy density factor value of 21,172 J/m4 for coal pillars in one-roadway interval mining is the lowest among the different schemes. Therefore, the one-roadway interval mining scheme is the optimal choice in roadway backfilling mining technology. The results can be treated as an important basis for the prevention and treatment of coal pillar instability and rockburst in roadway backfilling mining technology.

Description: Sensors, Vol. 18, Pages 2409: The Bluetooth Mesh Standard: An Overview and Experimental Evaluation Sensors doi: 10.3390/s18082409 Authors: Mathias Baert Jen Rossey Adnan Shahid Jeroen Hoebeke Mesh networks enable a many-to-many relation between nodes, which means that each node in the network can communicate with every other node using multi-hop communication and path diversity. As it enables the fast roll-out of sensor and actuator networks, it is an important aspect within the Internet of Things (IoT). Utilizing Bluetooth Low Energy (BLE) as an underlying technology to implement such mesh networks has gained a lot of interest in recent years. The result was a variety of BLE meshing solutions that were not interoperable because of the lack of a common standard. This has changed recently with the advent of the Bluetooth Mesh standard. However, a detailed overview of how this standard operates, performs and how it tackles other issues concerning BLE mesh networking is missing. Therefore, this paper investigates this new technology thoroughly and evaluates its performance by means of three approaches, namely an experimental evaluation, a statistical approach and a graph-based simulation model, which can be used as the basis for future research. Apart from showing that consistent results are achieved by means of all three approaches, we also identify possible drawbacks and open issues that need to be dealt with.

Description: Sustainability, Vol. 10, Pages 2604: Analysis of Guidelines and Identification of Characteristics Influencing the Deconstruction Potential of Buildings Sustainability doi: 10.3390/su10082604 Authors: Roberta Carvalho Machado Henor Artur de Souza Gustavo de Souza Veríssimo Growing concerns regarding environmental preservation and the fact that the construction industry is one of the sectors with the highest rates of resource consumption and waste generation, have encouraged the adoption of deconstruction as an alternative to the demolition of buildings at the end of their lifecycle. However, the choice of strategies to enable deconstruction requires an in-depth knowledge of how the building’s characteristics, combined with the procedures adopted in the deconstruction process, will affect the reutilization of materials and components. In this paper, characteristics relating to design for deconstruction (DfD) are identified and the influence of each characteristic on the viability of a deconstruction is analysed. A literature review is conducted to assess the guideline of DfD and to identify relevant characteristics. These characteristics are then divided into the following categories: direct influence enabling deconstruction; influence on the ease of the process; and, influence on prolonging a building’s lifecycle. A number of questions are suggested for analysing each characteristic, and these can be employed in the development of a methodology for evaluating a building’s deconstruction potential. The identification of characteristics involved in the deconstruction guidelines may assist in the optimization of projects and the planning of deconstruction processes.

Description: Sustainability, Vol. 10, Pages 2605: Building a More Sustainable Society? A Case Study on the Role of Sustainable Development in the Education and Early Career of Water and Environmental Engineers Sustainability doi: 10.3390/su10082605 Authors: Anu Vehmaa Meeri Karvinen Marko Keskinen Engineering education is critical for sustainability, given the key role that engineers have in shaping the development of our society. Yet, engineering studies have traditionally not been driven by sustainability-related knowledge and skills, but focused more on general computational skills and technical problem-solving. This has also been the case in our case study, which focuses on recent water and environmental engineering graduates in Finland. We studied the role that sustainable development has had in their education and early career through an extensive questionnaire and semi-structured interviews. The analysis was done in two ways: indirectly by comparing how well the key working life knowledge and skills recognized by the respondents correspond with sustainability-related skills, and directly by studying the graduates’ views towards the sustainable development and their possibilities to advance it in their work. The results show that although sustainability was not at the core of respondents’ studies, their key competencies correspond well with sustainability-related working life skills. The respondents also see that sustainable development has a central role in water and environmental engineering, although it is typically more visible at a strategic rather than a practical level. However, the results also indicate that several early-career engineers have deficient knowledge of sustainable development, and are therefore lacking the ability to fully connect the principles of sustainable development into their own expertise. Overall, the findings suggest that water and environmental engineers with their wide set of competencies have the potential to take on a larger role in building a more sustainable society. To ensure this, engineering education should emphasize the connection between the field and sustainable development and clearly link engineers’ core competencies with the skills required to promote sustainability.

Description: Sustainability, Vol. 10, Pages 2603: Historic Urban Landscapes: A Review on Trends and Methodologies in the Urban Context of the 21st Century Sustainability doi: 10.3390/su10082603 Authors: Arturo Azpeitia Santander Agustín Azkarate Garai-Olaun Ander de la Fuente Arana This article makes a critical reflection, questioning the notion of historical urban landscapes as a conceptual paradigm used for the basis of urban conservation in the twenty-first century. The study begins with a brief summary of the origins and subsequent evolution of this concept, highlighting the two key reference milestones: the Vienna Memorandum (UNESCO, 2005) and the Paris Recommendation (UNESCO, 2011). Subsequently, the focus of attention will be on highlighting the problems and difficulties posed by the management and protection of historic urban landscapes today. In this sense, the focus of attention will be placed on the assumption that change is an inherent part of the urban condition, since there is no consensus on what the limits of acceptable change in historic urban landscapes should be. It also emphasizes three factors that make this more difficult: (1) the reminiscences of the doctrines of the Weberian administration in the current models of government; (2) the subjective nature of the systems of indicators applied to the scope of historic cities; and (3) the opportunism of tactical urbanism, which, despite its shortcomings, is becoming an outstanding alternative for the methodological development of the historic urban landscapes.

Description: Minerals, Vol. 8, Pages 315: Biomineral Reactivity: The Kinetics of the Replacement Reaction of Biological Aragonite to Apatite Minerals doi: 10.3390/min8080315 Authors: Martina Greiner Lurdes Férnandez-Díaz Erika Griesshaber Moritz N. Zenkert Xiaofei Yin Andreas Ziegler Sabino Veintemillas-Verdaguer Wolfgang W. Schmahl We present results of bioaragonite to apatite conversion in bivalve, coral and cuttlebone skeletons, biological hard materials distinguished by specific microstructures, skeletal densities, original porosities and biopolymer contents. The most profound conversion occurs in the cuttlebone of the cephalopod Sepia officinalis, the least effect is observed for the nacreous shell portion of the bivalve Hyriopsis cumingii. The shell of the bivalve Arctica islandica consists of cross-lamellar aragonite, is dense at its innermost and porous at the seaward pointing shell layers. Increased porosity facilitates infiltration of the reaction fluid and renders large surface areas for the dissolution of aragonite and conversion to apatite. Skeletal microstructures of the coral Porites sp. and prismatic H. cumingii allow considerable conversion to apatite. Even though the surface area in Porites sp. is significantly larger in comparison to that of prismatic H. cumingii, the coral skeleton consists of clusters of dense, acicular aragonite. Conversion in the latter is sluggish at first as most apatite precipitates only onto its surface area. However, the process is accelerated when, in addition, fluids enter the hard tissue at centers of calcification. The prismatic shell portion of H. cumingii is readily transformed to apatite as we find here an increased porosity between prisms as well as within the membranes encasing the prisms. In conclusion, we observe distinct differences in bioaragonite to apatite conversion rates and kinetics depending on the feasibility of the reaction fluid to access aragonite crystallites. The latter is dependent on the content of biopolymers within the hard tissue, their feasibility to be decomposed, the extent of newly formed mineral surface area and the specific biogenic ultra- and microstructures.

Description: Minerals, Vol. 8, Pages 318: Mapping Surface Quartz Content in Sand Dunes Covered by Biological Soil Crusts Using Airborne Hyperspectral Images in the Longwave Infrared Region Minerals doi: 10.3390/min8080318 Authors: Shahar Weksler Offer Rozenstein Eyal Ben-Dor Biological soil crusts (BSCs), composed of cyanobacteria, algae, mosses, lichens, and fungi, are important ecosystem engineers that stabilize the quartz-rich dunes in the Nitzana study area near the Israel–Egypt border. The longwave infrared (LWIR) region of the electromagnetic spectrum is very useful for quartz identification since quartz reflectance in the visible, near infrared, and shortwave infrared (VIS-NIR-SWIR, 0.4–2.5 µm) spectral regions lacks identifying features, whereas in the LWIR region, the quartz emissivity spectrum presents a strong doublet feature. This emissivity feature can be used as a diagnostic tool for BSCs development in desert environments, because BSCs attenuate the quartz feature as a function of their successional development. A pair of day and night airborne hyperspectral images were acquired using the Specim AisaOWL LWIR sensor (7.7–12 µm) and processed using an innovative algorithm to reduce the atmospheric interference in this spectral domain. The resulting day and night apparent emissivity products were used to produce a surface quartz content map of the study area. The significant reduction in atmospheric interference resulted in a high correlation (R2 = 0.88) between quartz content in field samples determined by X-ray powder diffraction analysis and emissivity estimations from the airborne images. This, in turn, served as the ground truth to our quartz content map of the surface, and by proxy to the BSC.

Description: Minerals, Vol. 8, Pages 313: Reverse Flotation Separation of Fluorite from Calcite: A Novel Reagent Scheme Minerals doi: 10.3390/min8080313 Authors: Jianjun Wang Zihan Zhou Yuesheng Gao Wei Sun Yuehua Hu Zhiyong Gao Fluorite (CaF2), as an important strategic mineral source, is usually separated from calcite by the common froth flotation method, but this separation is still not selective enough. The development of a selective collector and/or depressant is the key to achieving high selective separation. 1-Hydroxyethylidene-1,1-diphosphonic acid (HEDP or H4L) is widely used as an environmentally friendly water treatment reagent due to its low cost and excellent anti-scaling performance in an aqueous solution. In this study, a novel reagent scheme was developed using HEDP as a fluorite depressant and sodium oleate (NaOL) as a calcite collector for the first time. When 3 × 10−5 mol/L of HEDP and 6 × 10−5 mol/L of NaOL were used at pH 6, the optimal selective separation for single minerals and mixed binary minerals was obtained. Zeta potential measurements indicated that HEDP possessed a stronger adsorption on fluorite than calcite, while NaOL did the opposite. This novel reagent scheme is of low cost, uses a small dosage, and is friendly to the environment, which makes it a promising reagent scheme for fluorite flotation in industrial application.

Description: Sensors, Vol. 18, Pages 2436: Bio-Inspired Covert Active Sonar Strategy Sensors doi: 10.3390/s18082436 Authors: Jiajia Jiang Xianquan Wang Fajie Duan Chunyue Li Xiao Fu Tingting Huang Lingran Bu Ling Ma Zhongbo Sun The covertness of the active sonar is a very important issue and the sonar signal waveform design problem was studied to improve covertness of the system. Many marine mammals produce call pulses for communication and echolocation, and existing interception systems normally classify these biological signals as ocean noise and filter them out. Based on this, a bio-inspired covert active sonar strategy was proposed. The true, rather than man-made sperm whale, call pulses were used to serve as sonar waveforms so as to ensure the camouflage ability of sonar waveforms. A range and velocity measurement combination (RVMC) was designed by using two true sperm whale call pulses which had excellent range resolution (RR) and large Doppler tolerance (DT). The range and velocity estimation methods were developed based on the RVMC. In the sonar receiver, the correlation technology was used to confirm the start and end time of sonar signals and their echoes, and then based on the developed range and velocity estimation method, the range and velocity of the underwater target were obtained. Then, the RVMC was embedded into the true sperm whale call-train to improve the camouflage ability of the sonar signal-train. Finally, experiment results were provided to verify the performance of the proposed method.

Description: Sensors, Vol. 18, Pages 2435: Quantitative Contact-Less Estimation of Energy Expenditure from Video and 3D Imagery Sensors doi: 10.3390/s18082435 Authors: Gregor Koporec Goran Vučković Radoje Milić Janez Perš Measurement of energy expenditure is an important tool in sport science and medicine, especially when trying to estimate the extent and intensity of physical activity. However, most approaches still rely on sensors or markers, placed directly on the body. In this paper, we present a novel approach using a fully contact-less, fully automatic method, that relies on computer vision algorithms and widely available and inexpensive imaging sensors. We rely on the estimation of the optical and scene flow to calculate Histograms of Oriented Optical Flow (HOOF) descriptors, which we subsequently augment with the Histograms of Absolute Flow Amplitude (HAFA). Descriptors are fed into regression model, which allows us to estimate energy consumption, and to a lesser extent, the heart rate. Our method has been tested both in lab environment and in realistic conditions of a sport match. Results confirm that these energy expenditures could be derived from purely contact-less observations. The proposed method can be used with different modalities, including near infrared imagery, which extends its future potential.

Description: Sensors, Vol. 18, Pages 2434: Smart Portable Devices Suitable for Cultural Heritage: A Review Sensors doi: 10.3390/s18082434 Authors: Federica Valentini Andrea Calcaterra Simonetta Antonaroli Maurizio Talamo This article reviews recent portable sensor technologies to apply in the Cultural Heritage (CH) fields. The review has been prepared in the form of a retrospective description of the sensor’s history and technological evolution, having: new nanomaterials for transducers, miniaturized, portable and integrated sensors, the wireless transmission of the analytical signals, ICT_Information Communication Technology and IoT_Internet of Things to apply to the cultural heritage field. In addition, a new trend of movable tattoo sensors devices is discussed, referred to in situ analysis, which is especially important when scientists are in the presence of un-movable and un-tangible Cultural Heritage and Art Work objects. The new proposed portable contact sensors (directly applied to art work objects and surfaces) are non-invasive and non-destructive to the different materials and surfaces of which cultural heritage is composed.

Description: Sensors, Vol. 18, Pages 2433: Multi-Camera Imaging System for UAV Photogrammetry Sensors doi: 10.3390/s18082433 Authors: Damian Wierzbicki In the last few years, it has been possible to observe a considerable increase in the use of unmanned aerial vehicles (UAV) equipped with compact digital cameras for environment mapping. The next stage in the development of photogrammetry from low altitudes was the development of the imagery data from UAV oblique images. Imagery data was obtained from side-facing directions. As in professional photogrammetric systems, it is possible to record footprints of tree crowns and other forms of the natural environment. The use of a multi-camera system will significantly reduce one of the main UAV photogrammetry limitations (especially in the case of multirotor UAV) which is a reduction of the ground coverage area, while increasing the number of images, increasing the number of flight lines, and reducing the surface imaged during one flight. The approach proposed in this paper is based on using several head cameras to enhance the imaging geometry during one flight of UAV for mapping. As part of the research work, a multi-camera system consisting of several cameras was designed to increase the total Field of View (FOV). Thanks to this, it will be possible to increase the ground coverage area and to acquire image data effectively. The acquired images will be mosaicked in order to limit the total number of images for the mapped area. As part of the research, a set of cameras was calibrated to determine the interior orientation parameters (IOPs). Next, the method of image alignment using the feature image matching algorithms was presented. In the proposed approach, the images are combined in such a way that the final image has a joint centre of projections of component images. The experimental results showed that the proposed solution was reliable and accurate for the mapping purpose. The paper also presents the effectiveness of existing transformation models for images with a large coverage subjected to initial geometric correction due to the influence of distortion.

Description: Sensors, Vol. 18, Pages 2432: A Terahertz CMOS V-Shaped Patch Antenna with Defected Ground Structure Sensors doi: 10.3390/s18082432 Authors: Hyeongjin Kim Wonseok Choe Jinho Jeong In this paper, a V-shaped patch antenna with defected ground structure is proposed at terahertz to overcome the limited performance of a standard complementary metal-oxide semiconductor (CMOS) patch antenna consisting of several metal layers and very thin interdielectric layers. The proposed V-shaped patch with slots allows the increased radiation resistance and broadband performance. In addition, the patch resonating at different frequency from the V-shaped patch is stacked on the top to broaden the impedance-matching bandwidth. More importantly, the slots are formed in the ground plane, which is called the defected ground structure, to further increase the radiation resistance and thus improve the bandwidth and efficiency. It is verified from electromagnetic simulations that the leakage waves from the defected ground can enhance the antenna directivity and gain by coherently interfering with the topside radiation. The proposed on-chip antenna is fabricated using a standard 65 nm CMOS process. The on-wafer measurement shows very wide bandwidth in input reflection coefficient (<−10 dB), greater than 28.7% from 240 to >320 GHz. The measured peak gain was as high as 5.48 dBi at 295 GHz. To the best of the authors’ knowledge, these results belong to the best performance among the terahertz CMOS on-chip antennas without using additional components or processes such as dielectric resonators, lens, or substrate thinning.

Description: Sensors, Vol. 18, Pages 2430: Relative Pose Based Redundancy Removal: Collaborative RGB-D Data Transmission in Mobile Visual Sensor Networks Sensors doi: 10.3390/s18082430 Authors: Xiaoqin Wang Y. Ahmet Şekercioğlu Tom Drummond Vincent Frémont Enrico Natalizio Isabelle Fantoni In this paper, the Relative Pose based Redundancy Removal (RPRR) scheme is presented, which has been designed for mobile RGB-D sensor networks operating under bandwidth-constrained operational scenarios. The scheme considers a multiview scenario in which pairs of sensors observe the same scene from different viewpoints, and detect the redundant visual and depth information to prevent their transmission leading to a significant improvement in wireless channel usage efficiency and power savings. We envisage applications in which the environment is static, and rapid 3D mapping of an enclosed area of interest is required, such as disaster recovery and support operations after earthquakes or industrial accidents. Experimental results show that wireless channel utilization is improved by 250% and battery consumption is halved when the RPRR scheme is used instead of sending the sensor images independently.

Description: Sensors, Vol. 18, Pages 2439: HemoKinect: A Microsoft Kinect V2 Based Exergaming Software to Supervise Physical Exercise of Patients with Hemophilia Sensors doi: 10.3390/s18082439 Authors: Fernando Mateo Emilio Soria-Olivas Juan Carrasco Santiago Bonanad Felipe Querol Sofía Pérez-Alenda Patients with hemophilia need to strictly follow exercise routines to minimize their risk of suffering bleeding in joints, known as hemarthrosis. This paper introduces and validates a new exergaming software tool called HemoKinect that intends to keep track of exercises using Microsoft Kinect V2’s body tracking capabilities. The software has been developed in C++ and MATLAB. The Kinect SDK V2.0 libraries have been used to obtain 3D joint positions from the Kinect color and depth sensors. Performing angle calculations and center-of-mass (COM) estimations using these joint positions, HemoKinect can evaluate the following exercises: elbow flexion/extension, knee flexion/extension (squat), step climb (ankle exercise) and multi-directional balance based on COM. The software generates reports and progress graphs and is able to directly send the results to the physician via email. Exercises have been validated with 10 controls and eight patients. HemoKinect successfully registered elbow and knee exercises, while displaying real-time joint angle measurements. Additionally, steps were successfully counted in up to 78% of the cases. Regarding balance, differences were found in the scores according to the difficulty level and direction. HemoKinect supposes a significant leap forward in terms of exergaming applicability to rehabilitation of patients with hemophilia, allowing remote supervision.

Description: Sensors, Vol. 18, Pages 2428: Narrowband Characterization of Near-Ground Radio Channel for Wireless Sensors Networks at 5G-IoT Bands Sensors doi: 10.3390/s18082428 Authors: Hicham Klaina Ana Vazquez Alejos Otman Aghzout Francisco Falcone In this contribution, a narrowband radio channel model is proposed for rural scenarios in which the radio link operates under near-ground conditions for application in wireless sensor networks dedicated to smart agriculture. The received power attenuation was measured for both transmitter and receiver antennas placed at two different heights above ground: 0.2 and 0.4 m. Three frequency ranges, proposed for future 5G-IoT use case in agriculture, were chosen: 868 MHz, 2.4 GHz and 5.8 GHz. Three ground coverings were tested in a rural scenario: soil, short and tall grass fields. The path loss was then estimated as dependent of the radio link range and a three-slope log-normal path loss model was tailored. Results are explained in terms of the first Fresnel zone obstruction. Commercial Zigbee sensor nodes operating at 2.4 GHz were used in a second experiment to estimate the link quality from the experimental Radio Signal Strength Indicator (RSSI) received values. Two sensor nodes were placed at the same elevation above ground as in the previous experiment, only for short grass field case. The Quality of Service performance was determined in terms of theoretical bit error rate achieved for different digital modulations—BPSK, 8PSK and 16QAM—concluding remarkable results for an obstructed radio link.

Description: Sensors, Vol. 18, Pages 2429: A PUF- and Biometric-Based Lightweight Hardware Solution to Increase Security at Sensor Nodes Sensors doi: 10.3390/s18082429 Authors: Rosario Arjona Miguel Ángel Prada-Delgado Javier Arcenegui Iluminada Baturone Security is essential in sensor nodes which acquire and transmit sensitive data. However, the constraints of processing, memory and power consumption are very high in these nodes. Cryptographic algorithms based on symmetric key are very suitable for them. The drawback is that secure storage of secret keys is required. In this work, a low-cost solution is presented to obfuscate secret keys with Physically Unclonable Functions (PUFs), which exploit the hardware identity of the node. In addition, a lightweight fingerprint recognition solution is proposed, which can be implemented in low-cost sensor nodes. Since biometric data of individuals are sensitive, they are also obfuscated with PUFs. Both solutions allow authenticating the origin of the sensed data with a proposed dual-factor authentication protocol. One factor is the unique physical identity of the trusted sensor node that measures them. The other factor is the physical presence of the legitimate individual in charge of authorizing their transmission. Experimental results are included to prove how the proposed PUF-based solution can be implemented with the SRAMs of commercial Bluetooth Low Energy (BLE) chips which belong to the communication module of the sensor node. Implementation results show how the proposed fingerprint recognition based on the novel texture-based feature named QFingerMap16 (QFM) can be implemented fully inside a low-cost sensor node. Robustness, security and privacy issues at the proposed sensor nodes are discussed and analyzed with experimental results from PUFs and fingerprints taken from public and standard databases.

Description: Sustainability, Vol. 10, Pages 2633: Scenario-Based Simulation of Tianjin City Using a Cellular Automata–Markov Model Sustainability doi: 10.3390/su10082633 Authors: Ruci Wang Hao Hou Yuji Murayama Rapid urbanization is occurring throughout China, especially in megacities. Using a land use model to obtain future land use/cover conditions is an essential method to prevent chaotic urban sprawl and imbalanced development. This study utilized historical Landsat images to create land use/cover maps to predict the land use/cover changes of Tianjin city in 2025 and 2035. The cellular automata–Markov (CA–Markov) model was applied in the simulation under three scenarios: the environmental protection scenario (EPS), crop protection scenario (CPS), and spontaneous scenario (SS). The model achieved a kappa value of 86.6% with a figure of merit (FoM) of 12.18% when compared to the empirical land use/cover map in 2015. The results showed that the occupation of built-up areas increased from 29.13% in 2015 to 38.68% (EPS), 36.18% (CPS), and 47.94% (SS) in 2035. In this context, current urbanization would bring unprecedented stress on agricultural resources and forest ecosystems, which could be attenuated by implementing protection policies along with decelerating urban expansion. The findings provide valuable information for urban planners to achieve sustainable development goals.

Description: Sustainability, Vol. 10, Pages 2629: Pathways to Coastal Resiliency: The Adaptive Gradients Framework Sustainability doi: 10.3390/su10082629 Authors: Elisabeth M. Hamin Yaser Abunnasr Max Roman Dilthey Pamela K. Judge Melissa A. Kenney Paul Kirshen Thomas C. Sheahan Don J. DeGroot Robert L. Ryan Brain G. McAdoo Leonard Nurse Jane A. Buxton Ariana E. Sutton-Grier Elizabeth A. Albright Marielos Arlen Marin Rebecca Fricke Current and future climate-related coastal impacts such as catastrophic and repetitive flooding, hurricane intensity, and sea level rise necessitate a new approach to developing and managing coastal infrastructure. Traditional “hard” or “grey” engineering solutions are proving both expensive and inflexible in the face of a rapidly changing coastal environment. Hybrid solutions that incorporate natural, nature-based, structural, and non-structural features may better achieve a broad set of goals such as ecological enhancement, long-term adaptation, and social benefits, but broad consideration and uptake of these approaches has been slow. One barrier to the widespread implementation of hybrid solutions is the lack of a relatively quick but holistic evaluation framework that places these broader environmental and societal goals on equal footing with the more traditional goal of exposure reduction. To respond to this need, the Adaptive Gradients Framework was developed and pilot-tested as a qualitative, flexible, and collaborative process guide for organizations to understand, evaluate, and potentially select more diverse kinds of infrastructural responses. These responses would ideally include natural, nature-based, and regulatory/cultural approaches, as well as hybrid designs combining multiple approaches. It enables rapid expert review of project designs based on eight metrics called “gradients”, which include exposure reduction, cost efficiency, institutional capacity, ecological enhancement, adaptation over time, greenhouse gas reduction, participatory process, and social benefits. The framework was conceptualized and developed in three phases: relevant factors and barriers were collected from practitioners and experts by survey; these factors were ranked by importance and used to develop the initial framework; several case studies were iteratively evaluated using this technique; and the framework was finalized for implementation. The article presents the framework and a pilot test of its application, along with resources that would enable wider application of the framework by practitioners and theorists.

Description: Sustainability, Vol. 10, Pages 2627: Photovoltaic Power Forecasting Based on EEMD and a Variable-Weight Combination Forecasting Model Sustainability doi: 10.3390/su10082627 Authors: Hui Wang Jianbo Sun Weijun Wang It is widely considered that solar energy will be one of the most competitive energy sources in the future, and solar energy currently accounts for high percentages of power generation in developed countries. However, its power generation capacity is significantly affected by several factors; therefore, accurate prediction of solar power generation is necessary. This paper proposes a photovoltaic (PV) power generation forecasting method based on ensemble empirical mode decomposition (EEMD) and variable-weight combination forecasting. First, EEMD is applied to decompose PV power data into components that are then combined into three groups: low-frequency, intermediate-frequency, and high-frequency. These three groups of sequences are individually predicted by the variable-weight combination forecasting model and added to obtain the final forecasting result. In addition, the design of the weights for combination forecasting was studied during the forecasting process. The comparison in the case study indicates that in PV power generation forecasting, the prediction results obtained by the individual forecasting and summing of the sequences after the EEMD are better than those from direct prediction. In addition, when the single prediction model is converted to a variable-weight combination forecasting model, the prediction accuracy is further improved by using the optimal weights.

Description: Sustainability, Vol. 10, Pages 2622: A Rough Multi-Criteria Decision-Making Approach for Sustainable Supplier Selection under Vague Environment Sustainability doi: 10.3390/su10082622 Authors: Huiyun Lu Shaojun Jiang Wenyan Song Xinguo Ming With the growing awareness of environmental and social issues, sustainable supply chain management (SSCM) has received considerable attention both in academia and industry. Supplier selection plays an important role in the successful implementation of sustainable supply chain management, because it can influence the performance of SSCM. Sustainable supplier selection is a typical multi-criteria decision-making problem involving subjectivity and vagueness. Although some previous researches of supplier selection use fuzzy approaches to deal with vague information, it has been criticized for requiring much priori information and inflexibility in manipulating vagueness. Moreover, the previous methods often omit the environmental and social evaluation criteria in the supplier selection. To manipulate these problems, a new approach based on the rough set theory and ELECTRE (ELimination Et Choix Traduisant la REalité) is developed in this paper. The novel approach integrates the strength of rough set theory in handling vagueness without much priori information and the merit of ELECTRE in modeling multi-criteria decision-making problem. Finally, a case study of sustainable supplier selection for solar air-conditioner manufacturer is provided to demonstrate the application and potential of the approach.

Description: Sustainability, Vol. 10, Pages 2624: Economic Transition and Changing Location of Manufacturing Industry in China: A Study of the Yangtze River Delta Sustainability doi: 10.3390/su10082624 Authors: Jiawei Wu Yehua Dennis Wei Qizhai Li Feng Yuan Industrial restructuring is widely considered an important force in regional economic growth and sustainable development. With increased globalization and economic transition, a dramatic industrial restructuring has been taking place in China. Applying geographically weighted shift-share model (GW-SSM) and geographically and temporally weighted regression model (GTWR), we analyze (re)location dynamics and determinants of the manufacturing industry in the Yangtze River Delta (YRD) from 1999 to 2013, with particular attention to the implications of economic transition and institutional restructuring. We find that high-tech and capital-intensive manufacturing industries agglomerated in coastal cities, while labor-intensive and resource-based sectors have become spatially more dispersed to peripheral areas. We also find that the development of service and high-tech industries, rising labor costs, and more strict environmental regulations have facilitated the geographic dispersion of labor- and pollution-intensive industries. Moreover, regions with advantages in intermediate goods, preferential policies, and urbanization economies are attractive to capital- and technology-intensive manufacturing industries. Our research suggests that development policies should be tailored to specific regions to promote local production and innovative networks and make manufacturing industries more competitive.

Description: Sustainability, Vol. 10, Pages 2621: Adoption of Conservation Tillage on the Semi-Arid Loess Plateau of Northwest China Sustainability doi: 10.3390/su10082621 Authors: Qingfeng Han Kadambot H. M. Siddique Fengmin Li Conservation tillage is an important approach to prevent water loss and soil erosion and promote soil fertility that has been adopted widely throughout the world. However, despite promotion of the benefits of conservation tillage, obstacles are still encountered in some regions. A survey of 385 farmer households in the semi-arid Loess Plateau of China was conducted to assess the adoption of conservation tillage (ACT). This investigation was located in two counties that have run conservation tillage demonstrations with wheat for at least eight years. A binary logistic regression model was used to quantify the factors determining whether or not farmers adopt conservation tillage. Farmer’s education level, the influence of training, and field demonstrations by agricultural departments had significant positive effects on ACT. Although the adoption rate of conservation tillage in this paper was very high (89%), farmers were reluctant to continue practicing conservation tillage based on their experiences, which is contrary to the expectations of the government. The area available for planting winter wheat and the number of arable plots per household also had significant positive effects on ACT. However, the total cultivated area of land per household had a significant negative impact on ACT. Farmer awareness of conservation tillage technology, the distance from a farmer’s house to the nearest agricultural market, and the size of the active labor force in the family had significant negative impacts on ACT. These results will help in the development of more effective and targeted policies to improve the sustainability of farming systems on the semi-arid Loess Plateau.

Description: Sustainability, Vol. 10, Pages 2620: Transition towards Energy Efficiency: Developing the Nigerian Building Energy Efficiency Code Sustainability doi: 10.3390/su10082620 Authors: Susanne Geissler Doris Österreicher Ene Macharm In Nigeria, there is an estimated deficit of 17 million housing units. Power supply is insufficient, and the electricity supply for about 60 million Nigerians relies on private generators, causing noise, pollution, and high expenditures for mainly imported fuel. Altogether, current challenges clearly demonstrate the need for effective energy efficiency policies targeting also the building sector. The Nigerian Energy Support Program began in 2013, among others, with the objective being to support the Nigerian Government in developing the Nigerian Building Energy Efficiency Code. This paper presents two preparatory activities carried out in order to come up with suggestions for a legal framework well suited for the situation on the ground: the Case Study Building Analysis carried out in collaboration with a Nigerian developer and the Nigerian Building Energy Efficiency Guideline, elaborated together with stakeholders. The results of preparatory activities pointed out that the code must put emphasis on climate adaptive design and must define requirements and procedures in a clear and simple way to allow for effective enforcement. Only then can energy-efficient mass housing be feasible in Nigeria. The paper concludes with a description of the Nigerian Building Energy Efficiency Code (BEEC), officially approved and launched by the Federal Minister of Power, Works and Housing on 29 August 2017.

Description: Sustainability, Vol. 10, Pages 2619: Are the World-Leading Primary Silver Mines Exhausting? Sustainability doi: 10.3390/su10082619 Authors: Marcello Ruberti Stefania Massari Silver is one of the rarest metals in nature and certainly among the most used ones, not only as precious good for financial investments but also for many industrial critical applications. Because it would be very difficult to analyze the situation regarding the future global availability of silver as a commodity in general, due to the necessity of a large amount of data which are hardly available, we have focused only on the mining production of primary silver. In particular, the study regards the activities of a sample consisting of twelve of the world top fifteen leading primary silver mines, which represent the 54% of the worldwide primary silver production and 16% of the global silver mining production. We have investigated the related exploitation state and trends of these twelve sites by elaborating their last ten-years statistics on silver production, ore grades, resources and reserves. The findings of this study, in short, are that the cumulative average silver ore grades, both in extracted mineral, resources and reserves, of the above selected mines, have decreased and also that the new mining fields (Dukat, San Bartolomé, Pirquitas, Saucito) have lower silver content indexes than the older ones.

Description: Sustainability, Vol. 10, Pages 2617: Exploring Twitter for CSR Disclosure: Influence of CEO and Firm Characteristics in Latin American Companies Sustainability doi: 10.3390/su10082617 Authors: Yuli Marcela Suárez-Rico Mauricio Gómez-Villegas María Antonia García-Benau Social networks, which are characterised by accessibility and interactivity, offer great potential for dialogue between companies and stakeholders, for example as platforms for publishing information on aspects of corporate social responsibility (CSR). In this paper, we use a synthetic index to analyse levels of CSR disclosure via Twitter, and identify explanatory variables of this disclosure by studying the demographic characteristics of the Chief Executive Officer (CEO) and of the company. This synthetic index was based on data for 93 companies located in the four countries of the Pacific Alliance (Chile, Colombia, Mexico, and Peru), using categories based on the 2016 Global Reporting Initave (GRI) Standards. The tweets were compiled during a period of two months in 2017, immediately before and after the publication of each CSR report. The synthetic index was taken as the dependent variable and used as the basis for multivariate regression analysis to identify the relationship between the level of CSR disclosure on Twitter and the characteristics of the firm and its CEO. The results obtained show that firms operating in environmentally-sensitive industries present higher levels of CSR disclosure on Twitter than those in other sectors. By country of origin, the Colombian and Chilean companies offered higher levels of disclosure than those in Mexico and Peru. The regression analysis revealed a positive relationship between the firm operating in a sensitive industry and its level of CSR disclosure on Twitter, and an inverse relationship between the latter variable and the tenure of the CEO.

Description: Minerals, Vol. 8, Pages 323: (10.4) Face of Ordered and Disordered Dolomite, MgCa(CO3)2: A Computational Study to Reveal the Growth Mechanism Minerals doi: 10.3390/min8080323 Authors: Marco Bruno Erica Bittarello In this study, the stability of the (10.4) face of dolomite was systematically investigated. The surface energies at 0 K of the different (10.4) surfaces resulting from the cut of both ordered and disordered bulk structures were determined and compared, to establish how different atomic configurations (surface terminations) can affect the stability of the investigated face. To study the thermodynamic behavior of a surface, a 2D periodic slab model and the ab initio CRYSTAL code were adopted. The surface energies of the (10.4) faces of calcite and magnesite were also calculated in order to compare them with those of the different terminations of the (10.4) face of dolomite. Our calculations showed that the bulk of the dolomite crystal must have an ordered structure to reach the minimum of the energy, whereas the (10.4) surface is more stable when its structure is disordered. A growth model of the (10.4) face has been proposed: the peculiarity of this model consists in the existence of some disordered layers forming at the interface crystal/solution, which arrange in an ordered structure once covered by others disordered layers resulting by the spiral steps propagation.

Description: Minerals, Vol. 8, Pages 322: Particle Size Distribution Effects on the Strength Characteristic of Cemented Paste Backfill Minerals doi: 10.3390/min8080322 Authors: Jiangyu Wu Meimei Feng Zhanqing Chen Xianbiao Mao Guansheng Han Yiming Wang It is of great significance, for economic, environmental and security reasons, to investigate the strength characteristic of underground cemented paste backfill (CPB). Consequently, an ultrasonic test, uniaxial and triaxial compression experiment, and acoustic emission (AE) monitoring were carried out on CPB, for which the particles satisfied Talbot gradation. The homogeneity of CPB specimens was evaluated by ultrasonic pulse velocity (UPV). The stress–strain behavior and AE characteristic of CPB specimens under different Talbot indices and confining pressures were investigated. The effects of the particle size distribution and the confining pressure on the peak strength of CPB were analyzed. The strength parameter model of CPB under the coupled influence of the particle size distribution and the confining pressure was constructed based on the Mohr–Coulomb strength criterion. The results show that the peak strength of CPB is positively linear with confining pressure, however, the relationship between its strength parameters and the Talbot index can be characterized by a quadratic polynomial function. This suggests that there is an optimal gradation of particles reflected in the maximum strength of CPB.

Description: Minerals, Vol. 8, Pages 319: Fault Zone Evolution and Development of a Structural and Hydrological Barrier: The Quartz Breccia in the Kiggavik Area (Nunavut, Canada) and Its Control on Uranium Mineralization Minerals doi: 10.3390/min8080319 Authors: Alexis Grare Olivier Lacombe Julien Mercadier Antonio Benedicto Marie Guilcher Anna Trave Patrick Ledru John Robbins In the Kiggavik area (Nunavut, Canada), major fault zones along, or close to, where uranium deposits are found are often associated with occurrence of thick quartz breccia (QB) bodies. These bodies formed in an early stage (~1750 Ma) of the long-lasting tectonic history of the Archean basement, and of the Proterozoic Thelon basin. The main characteristics of the QB are addressed in this study; through field work, macro and microscopic observations, cathodoluminescence microscopy, trace elements, and oxygen isotopic signatures of the quartz forming the QB. Faults formed earlier during syn- to post-orogenic rifting (1850–1750 Ma) were subsequently reactivated, and underwent cycles of cataclasis, pervasive silicification, hydraulic brecciation, and quartz recrystallization. This was synchronous with the circulation of meteoric fluids mixing with Si-rich magmatic-derived fluids at depth, and were coeval with the emplacement of the Kivalliq igneous suite at 1750 Ma. These processes led to the emplacement of up to 30 m thick QB, which behaved as a mechanically strong, transverse hydraulic barrier that localized later fracturing, and compartmentalized/channelized vertical flow of uranium-bearing fluids after the deposition of the Thelon Basin (post 1750 Ma). The development and locations of QB control the location of uranium mineralization in the Kiggavik area.

Description: Sensors, Vol. 18, Pages 2448: Application-Aware Anomaly Detection of Sensor Measurements in Cyber-Physical Systems Sensors doi: 10.3390/s18082448 Authors: Amin Ghafouri Aron Laszka Koutsoukos Detection errors such as false alarms and undetected faults are inevitable in any practical anomaly detection system. These errors can create potentially significant problems in the underlying application. In particular, false alarms can result in performing unnecessary recovery actions while missed detections can result in failing to perform recovery which can lead to severe consequences. In this paper, we present an approach for application-aware anomaly detection (AAAD). Our approach takes an existing anomaly detector and configures it to minimize the impact of detection errors. The configuration of the detectors is chosen so that application performance in the presence of detection errors is as close as possible to the performance that could have been obtained if there were no detection errors. We evaluate our result using a case study of real-time control of traffic signals, and show that the approach outperforms significantly several baseline detectors.

Description: Sensors, Vol. 18, Pages 2444: Utilization of Inexpensive Carbon-Based Substrates as Platforms for Sensing Sensors doi: 10.3390/s18082444 Authors: Minh Tran Ahmad Fallatah Alison Whale Sonal Padalkar Gold (Au) has been widely used as a material for Surface Enhanced Raman Spectroscopy (SERS) due to its plasmonic properties, stability and biocompatibility. Conventionally for SERS application, Au is deposited on a rigid substrate such as glass or silicon. The rigid substrates severely limit analyte collection efficiency as well as portability. Here, flexible substrates like carbon cloth and carbon paper were investigated as potential substrate candidates for SERS application. The flexible substrates were coated with Au nanostructures by electrodeposition. Model analyte, Rhodamine 6G was utilized to demonstrate the capabilities of the flexible SERS substrates. Additionally, the pesticide paraoxon was also detected on the flexible SERS substrates as well as on a real sample like the apple fruit.

Description: Sensors, Vol. 18, Pages 2441: A Label-Free Fluorescent Assay for the Rapid and Sensitive Detection of Adenosine Deaminase Activity and Inhibition Sensors doi: 10.3390/s18082441 Authors: Xinxing Tang Kefeng Wu Han Zhao Mingjian Chen Changbei Ma Adenosine deaminase (ADA), able to catalyze the irreversible deamination of adenosine into inosine, can be found in almost all tissues and plays an important role in several diseases. In this work, we developed a label-free fluorescence method for the detection of adenosine deaminase activity and inhibition. In the presence of ADA, ATP has been shown to be hydrolyzed. The ATP aptamer was shown to form a G-quadruplex/thioflavin T (ThT) complex with ThT and exhibited an obvious fluorescence signal. However, the ATP aptamer could bind with ATP and exhibited a low fluorescence signal because of the absence of ADA. This assay showed high sensitivity to ADA with a detection limit of 1 U/L based on an SNR of 3 and got a good linear relationship within the range of 1–100 U/L with R2 = 0.9909. The LOD is lower than ADA cutoff value (4 U/L) in the clinical requirement and more sensitive than most of the reported methods. This technique exhibited high selectivity for ADA against hoGG I, UDG, RNase H and λexo. Moreover, this strategy was successfully applied for assaying the inhibition of ADA using erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA) and, as such, demonstrated great potential for the future use in the diagnosis of ADA-relevant diseases, particularly in advanced drug development.

Description: Sensors, Vol. 18, Pages 2440: A Privacy Preserving Scheme for Nearest Neighbor Query Sensors doi: 10.3390/s18082440 Authors: Yuhang Wang Zhihong Tian Hongli Zhang Shen Su Wei Shi In recent years, location privacy concerns that arise when using the nearest neighbor query services have gained increasing attention, as such services have become pervasive in mobile social networks devices and the IoT environments. State-of-the-art privacy preservation schemes focus on the obfuscation of the location information, which has suffered from various privacy attacks and the tradeoff of the quality of service. By noticing the fact that the user’s location could be replaced by their surrounding wireless sensor infrastructures in proximity, in this paper, we propose a wireless sensor access point-based scheme for the nearest neighbor query, without using the location of the user. Then, a noise-addition-based method that preserves user’s location privacy was proposed. To further strengthen the adaptability of the approach to real-world environments, several performance-enhancing methods are introduced, including an R-tree-based Noise-Data Retrieval Algorithm (RNR), and a nearest neighbor query method based on our research. Both performance and security evaluations are conducted to validate our approach. The results show the effectiveness and the practicality of our work.

Description: Sensors, Vol. 18, Pages 2450: Features of X-Band Radar Backscattering Simulation Based on the Ocean Environmental Parameters in China Offshore Seas Sensors doi: 10.3390/s18082450 Authors: Tao Wu Zhensen Wu Jiaji Wu Gwanggil Jeon Liwen Ma The X-band marine radar has been employed as a remote sensing tool for sea state monitoring. However, there are few literatures about sea spectra considering both the wave parameters and short wind-wave spectra in China Offshore Seas, which are of theoretical and practical significance. Based on the wave parameters acquired from the European Centre for Medium-Range Weather Forecasts reanalysis data (ERA-Interim reanalysis data) during 36 months from 2015 to 2017, a finite depth sea spectrum considering both wind speeds and ocean environmental parameters is established in this study. The wave spectrum is then built into a modified two-scale model, which can be related to the ocean environmental parameters (wind speeds and wave parameters). The final results are the mean backscattering coefficients over the variety of sea states at a given wind speed. As the model predicts, the monthly maximum backscattering coefficients in different seas change slowly (within 4 dB). In addition, the differences of the backscattering coefficients in different seas are quite small during azimuthal angles of 0° to 90° and 270° to 360° with a relative error within 1.5 dB at low wind speed (5 m/s) and 2 dB at high wind speed (10 m/s). With the method in the paper, a corrected result from the experiment can be achieved based on the relative error analysis in different conditions.

Description: Sustainability, Vol. 10, Pages 2659: Research on the Influence of Real Estate Development on Private Investment: A Case Study of China Sustainability doi: 10.3390/su10082659 Authors: Jiangtao Li Jianyue Ji Huiwen Guo Lei Chen Private investment in China, as a developing country, is an important source of financing for Chinese SMEs (Small and Medium-Size Enterprises) and has played a major role in the development of the real economy. However, in 2016, the growth rate of private investment in China dropped from 10.18% to 3.17%, which had a significant impact on the real economy. At the same time, China’s real estate market has developed rapidly, attracting a large number of capital inflows. The relationship between real estate development and private investment in China is worth considering. This study first, theoretically analyzes the influence mechanism of real estate industry on private investment, pointing out that within a modest development range, the development of real estate industry can promote private investment through the industrial linkage, urbanization, and balance sheet effects, but when real estate is overdeveloped, it has an inhibitory effect on private investment through vampire effect, raising costs and reducing demand effect. In other words, real estate has different effects on private investment in different developmental periods. Therefore, there is a non-linear relationship between the two variables. Second, the relevant provincial panel data of 31 provinces in mainland China from 2003 to 2015 were selected. Using the dynamic panel system Generalized Method of Moments (GMM), this study estimated the correlation between real estate development and private investment. The empirical results showed that the development of the real estate industry has a significant impact on the level of private investment; the two showing an “inverted U-shaped” relationship. At present, in some provinces in China, the real estate industry has exceeded the inverted U-shaped threshold. To boost the vitality of private investment in promoting real economic growth, the development of the real estate industry should be restricted, and house prices should be properly regulated.

Description: Sustainability, Vol. 10, Pages 2657: Numerical Thermal Characterization and Performance Metrics of Building Envelopes Containing Phase Change Materials for Energy-Efficient Buildings Sustainability doi: 10.3390/su10082657 Authors: Mingli Li Guoqing Gui Zhibin Lin Long Jiang Hong Pan Xingyu Wang Residential and commercial buildings consume nearly 40 percent of total USA energy use and account for one-third of total greenhouse gas emissions. The challenges are how to effectively promote energy efficiency in buildings to respond to the high financial burden of energy consumption, while reducing pollution. Phase change materials (PCMs) have been used as passive energy storage for building systems. Along this vein, this study aims to numerically elucidate the design parameters of building envelopes strengthened by PCM layers, and unveil their impacts on building energy efficiency. Critical design variables, such as the thickness of the PCM layer, the latent heat of PCMs, or melting temperature of PCMs were selected for a parametric study, while performance metrics were used to assess building efficiency. Results revealed that PCM-enabled building walls exhibited different levels of improvement, in terms of reduction of peak temperature and temperature swings. Among the variables, the selection of the proper melting point for a PCM was identified as the most crucial parameter for determining building energy efficiency, while the heat of fusion was also observed as a critical property of PCM for building potential. Findings also demonstrated that the placement of the PCM near the interior wall surface could achieve higher efficiency, as compared to other cases. Results also showed that the thermal conductivity of PCM has a minimum contribution to energy storage capacity.

Description: Sensors, Vol. 18, Pages 2451: Interaction of Lamb Wave Modes with Weak Material Nonlinearity: Generation of Symmetric Zero-Frequency Mode Sensors doi: 10.3390/s18082451 Authors: Xiaoqiang Sun Xiangyan Ding Feilong Li Shijie Zhou Yaolu Liu Ning Hu Zhongqing Su Youxuan Zhao Jun Zhang Mingxi Deng The symmetric zero-frequency mode induced by weak material nonlinearity during Lamb wave propagation is explored for the first time. We theoretically confirm that, unlike the second harmonic, phase-velocity matching is not required to generate the zero-frequency mode and its signal is stronger than those of the nonlinear harmonics conventionally used, for example, the second harmonic. Experimental and numerical verifications of this theoretical analysis are conducted for the primary S0 mode wave propagating in an aluminum plate. The existence of a symmetric zero-frequency mode is of great significance, probably triggering a revolutionary progress in the field of non-destructive evaluation and structural health monitoring of the early-stage material nonlinearity based on the ultrasonic Lamb waves.

Description: Sustainability, Vol. 10, Pages 2655: Substructure Hybrid Simulation Boundary Technique Based on Beam/Column Inflection Points Sustainability doi: 10.3390/su10082655 Authors: Zaixian Chen Xueyuan Yan Hao Wang Xingji Zhu Billie F. Spencer Compatibility among substructures is an issue for hybrid simulation. Traditionally, the structure model is regarded as the idealized shear model. The equilibrium and compatibility of the axial and rotational direction at the substructure boundary are neglected. To improve the traditional boundary technique, this paper presents a novel substructure hybrid simulation boundary technique based on beam/column inflection points, which can effectively avoid the complex operation for realizing the bending moment at the boundary by using the features of the inflection point where the bending moment need not be simulated in the physical substructure. An axial displacement prediction technique and the equivalent force control method are used to realize the proposed method. The numerical simulation test scheme for the different boundary techniques was designed to consider three factors: (i) the different structural layers; (ii) the line stiffness ratio of the beam to column; and (iii) the peak acceleration. The simulation results for a variety of numerical tests show that the proposed technique shows better performance than the traditional technique, demonstrating its potential in improving HS test accuracy. Finally, the accuracy and feasibility of the proposed boundary technique is verified experimentally through the substructure hybrid simulation tests of a six-story steel frame model.

Description: Minerals, Vol. 8, Pages 326: Hydrotalcite and Hydrocalumite in Mortar Binders from the Medieval Castle of Portilla (Álava, North Spain): Accurate Mineralogical Control to Achieve More Reliable Chronological Ages Minerals doi: 10.3390/min8080326 Authors: Graciela Ponce-Antón Luis Angel Ortega Maria Cruz Zuluaga Ainhoa Alonso-Olazabal Jose Luis Solaun Mortars from different stratigraphic units at Portilla Castle (Alava, North Spain) have been analyzed for mineralogical characterization before radiocarbon dating. The mortar binder at Portilla Castle is composed not only of neoformation calcite but also of double-layered hydroxide (LDH) minerals such as hydrotalcite and hydrocalumite. The mineralogy of several fractions of the binder has been analyzed to determine the granulometric distribution of minerals in the binder. The continuous monitoring of mineralogy during the extraction of different grain size fractions has been performed by using a scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric analyses (TGA). Hydrotalcite and hydrocalumite-bearing mortar binders give older ages than expected since they introduce dead carbon into the system.

Description: Sustainability, Vol. 10, Pages 2666: Understanding the Spontaneous Spreading of Stone Bunds in Ethiopia: Implications for Sustainable Land Management Sustainability doi: 10.3390/su10082666 Authors: Meskerem Abi Aad Kessler Peter Oosterveer Degefa Tolossa This study deals with the spontaneous spreading of stone bunds in the central Ethiopian highlands, i.e., the adoption and implementation of stone bunds by farmers on their own initiative. The study tests the hypothesis that spontaneously implemented stone bunds, as compared to stone bunds implemented by mass mobilization campaigns, are more integrated with other land management practices and lead to higher yields. Data are collected in the Girar Jarso woreda through field observations and household surveys. Descriptive statistics are used to analyze and test the data at 1% and 5% probability levels. Results show that stone bunds are spontaneously implemented mainly on farmlands located nearby the homesteads where farmers perceive severe erosion, poor soil fertility and steep slope gradients. Compared to stone bunds implemented by mass mobilization, spontaneously implemented stone bunds are perceived as better maintained, more frequently modified to fit the farming system and better integrated with soil fertility management practices, such as applying fertilizer, compost and manure. Particularly, this better integration with other practices is very important, because it makes stone bunds more effective in reducing erosion, leading to beneficial effects on soil moisture and soil productivity, as perceived by farmers. The study, therefore, suggests that the mass mobilization campaign should use a more participatory and integrated approach, in which there is ample space for awareness raising and learning concerning the benefits of integrated farm management, and in which farmers themselves have a leading role in the decision on where to construct stone bunds. Such a strategy will lead to more sustainable impact on soil fertility and food security than the current top-down intervention approach.

Description: Sustainability, Vol. 10, Pages 2674: Reputation Effects in Socially Driven Sharing Economy Transactions Sustainability doi: 10.3390/su10082674 Authors: Maarten ter Huurne Amber Ronteltap Chenhui Guo Rense Corten Vincent Buskens Reputation has often been proposed as the central mechanism that creates trust in the sharing economy. However, some sharing platforms that focus primarily on social rather than economically driven exchanges have managed to facilitate exchanges between users without the use of a reputation system. This could indicate that socially driven exchanges are in less need of reputation systems and that having sufficient trust is less problematic. We examine the effect of seller reputation on sales and price as proxies for trust, using a large dataset from a Dutch meal-sharing platform. This platform aims to stimulate social interactions between people via meal sharing. Multilevel regression analyses were used to test the association of reputation with trust. Our main empirical results are that reputation affects both sales and price positively, consistent with the existing reputation literature. We also found evidence of the presence of an information effect, i.e., the influence of reputation on sharing decreases when additional profile information is provided (e.g., a profile photo, a product description). Our results thus confirm the effectiveness of reputation in more socially driven exchanges also. Consequently, platform owners are advised to use reputation on their platform to increase sharing between its users.

Description: Sensors, Vol. 18, Pages 2472: Multiple Instances QoS Routing in RPL: Application to Smart Grids Sensors doi: 10.3390/s18082472 Authors: Jad Nassar Matthieu Berthomé Jérémy Dubrulle Nicolas Gouvy Nathalie Mitton Bruno Quoitin The Smart Grid (SG) aims to transform the current electric grid into a “smarter” network where the integration of renewable energy resources, energy efficiency and fault tolerance are the main benefits. This is done by interconnecting every energy source, storage point or central control point with connected devices, where heterogeneous SG applications and signalling messages will have different requirements in terms of reliability, latency and priority. Hence, data routing and prioritization are the main challenges in such networks. So far, RPL (Routing Protocol for Low-Power and Lossy networks) protocol is widely used on Smart Grids for distributing commands over the grid. RPL assures traffic differentiation at the network layer in wireless sensor networks through the logical subdivision of the network in multiple instances, each one relying on a specific Objective Function. However, RPL is not optimized for Smart Grids, as its main objective functions and their associated metric does not allow Quality of Service differentiation. To overcome this, we propose OFQS an objective function with a multi-objective metric that considers the delay and the remaining energy in the battery nodes alongside with the dynamic quality of the communication links. Our function automatically adapts to the number of instances (traffic classes) providing a Quality of Service differentiation based on the different Smart Grid applications requirements. We tested our approach on a real sensor testbed. The experimental results show that our proposal provides a lower packet delivery latency and a higher packet delivery ratio while extending the lifetime of the network compared to solutions in the literature.

Description: Sensors, Vol. 18, Pages 2465: Improving Classification Algorithms by Considering Score Series in Wireless Acoustic Sensor Networks Sensors doi: 10.3390/s18082465 Authors: Amalia Luque Javier Romero-Lemos Alejandro Carrasco Julio Barbancho The reduction in size, power consumption and price of many sensor devices has enabled the deployment of many sensor networks that can be used to monitor and control several aspects of various habitats. More specifically, the analysis of sounds has attracted a huge interest in urban and wildlife environments where the classification of the different signals has become a major issue. Various algorithms have been described for this purpose, a number of which frame the sound and classify these frames, while others take advantage of the sequential information embedded in a sound signal. In the paper, a new algorithm is proposed that, while maintaining the frame-classification advantages, adds a new phase that considers and classifies the score series derived after frame labelling. These score series are represented using cepstral coefficients and classified using standard machine-learning classifiers. The proposed algorithm has been applied to a dataset of anuran calls and its results compared to the performance obtained in previous experiments on sensor networks. The main outcome of our research is that the consideration of score series strongly outperforms other algorithms and attains outstanding performance despite the noisy background commonly encountered in this kind of application.

Description: Sustainability, Vol. 10, Pages 2676: Measuring Social Vulnerability to Flood Disasters in China Sustainability doi: 10.3390/su10082676 Authors: Ming Zhang Wenbo Xiang Meilan Chen Zisen Mao To proactively prevent losses from flood disasters and subsequent potential human conflicts, it is critical to measure the social vulnerability of a country or a region to flood. In this article, we first propose a list of potential indicators for measuring this social vulnerability. These indicators’ significances are then tested based on their correlation coefficients with a vulnerability index obtained using nonparametric Data Envelopment Analysis. In the final measurement system, there are nine indicators: the proportion of the primary industry, infrastructure development level, income gap between urban and rural residents, the proportion of population over 60 years old, the proportion of children under 14 years old, the number of people receiving minimum income assistance, and the number of disasters per year. We then conduct principal component analysis to evaluate the social vulnerability level. Our results show that the social vulnerability level is mostly impacted by the economic principal component and the demographic and social security principal component. Moreover, our results also confirm that the social vulnerability level to flood in China declined overall from 2003 to 2015.

Description: Sustainability, Vol. 10, Pages 2673: The Public Willingness to Pay for Reducing the Incidence of Hazardous Chemical Spill Accidents by Half in South Korea Sustainability doi: 10.3390/su10082673 Authors: Hye-Jeong Lee Hyo-Jin Kim Seung-Hoon Yoo Hazardous chemical spill (HCS) accidents, which occur due to careless workers, transport accidents, etc., can be harmful to humans. Recently, an average of 96 cases of HCS accidents have taken place in South Korea annually. As a result, the government is trying to reduce the incidence of HCS accidents by 50%. Government officials are seeking information about the value that the enforcement of the reduction plan will bring for the public. This knowledge will help government officials decide whether to implement the reduction plan. This article seeks to acquire information about the public willingness to pay (WTP) for the reduction plan, employing the contingent valuation (CV) technique. For this purpose, a total of 1000 households living in South Korea participated in the CV survey in 2017. The data on the WTP were gathered using a dichotomous choice question and analyzed using the spike model. Forty-five percent of the respondents were willing to accept an increase in income taxes to carry out the reduction plan. The mean household WTP estimate was obtained as KRW 3830 (USD 3.41) per annum. The national value expanded from the sample to the population is worth KRW 74.8 billion (USD 66.6 million) per year. This value implies the public value of the reduction plan and can be applied in policy analysis and decision-making concerning the reduction of the incidence of HCS accidents.

Description: Sustainability, Vol. 10, Pages 2671: The Sustainable Characteristic of Bio-Bi-Phase Flow of Peristaltic Transport of MHD Jeffrey Fluid in the Human Body Sustainability doi: 10.3390/su10082671 Authors: Ahmed Zeeshan Nouman Ijaz Tehseen Abbas Rahmat Ellahi This study deals with the peristaltic transport of non-Newtonian Jeffrey fluid with uniformly distributed identical rigid particles in a rectangular duct. The effects of a magnetohydrodynamics bio-bi-phase flow are taken into account. The governing equations for mass and momentum are simplified using the fact that wavelength is much greater than the amplitude and small Reynolds number. A closed-form solution for velocity is obtained by means of the eigenfunction expansion method whereby pressure rise is numerically calculated. The results are graphically presented to observe the effects of different physical parameters and the suitability of the method. The results for hydrodynamic, Newtonian fluid, and single-phase problems can be respectively obtained by taking the Hartmann number (M = 0), relaxation time (λ1=0), and volume fraction (C = 0) as special cases of this problem.

Description: Sustainability, Vol. 10, Pages 2591: Reducing Seismic Vulnerability and Energy Demand of Cities through Green Infrastructure Sustainability doi: 10.3390/su10082591 Authors: Riccardo Privitera Daniele La Rosa Historically, urbanization processes in Italy resulted in built environments with high levels of seismic vulnerability, low energy efficiency and a lack of green spaces. The latter represent the main providers of ecosystem services in cities and play a relevant role in reducing the effects of climate change by the regulation of microclimate and urban heat islands that are responsible for building energy consumption. Despite their importance in providing ecosystem services, the implementation of green infrastructure challenges limited financial resources for the public acquisition of private plots. This paper proposes a strategy to implement an urban green infrastructure aimed at generating a double positive effect on cities by triggering seismic retrofitting and the reduction of cooling energy demand of the existing urban fabric. This is proposed through a transfer of development rights program where landowners gain economic incentives to adopt seismic retrofitting interventions and, at the same time, public administrations implement the green infrastructure in the portion of areas transferred to the municipality. The energy efficiency of buildings closer to the green infrastructure, therefore, benefits from the cooling effects of this new greenery. The strategy is tested under different scenarios of acquisition of private land by public administrations in the metropolitan area of Catania (Italy).

Description: Sustainability, Vol. 10, Pages 2588: Identifying Economic Growth Convergence Clubs and Their Influencing Factors in China Sustainability doi: 10.3390/su10082588 Authors: Feng Li Guangdong Li Weishan Qin Jing Qin Haitao Ma Balanced and coordinated economic development across regions is a critical goal of regional economic development and new-type urbanization in China. However, few studies have examined economic growth convergence clubs at the county level. To extend the research on convergence clubs, this research applies a log t convergence test and a dynamic spatial ordered probit model (DSOP) to endogenously identify economic growth convergence clubs in counties and to examine the influence of initial states and structures on club convergence probability. The study sample covers 2286 counties of China from 1992 to 2010. The results show significant convergence club patterns at the county levels, resulting in the gradual formation of six convergence clubs. The DSOP estimation results show that per capita fixed assets, population density, and industrialization have promoted convergence club formation to varying degrees.

Description: Sustainability, Vol. 10, Pages 2594: Resilient Entrepreneurship among European Higher Education Graduates Sustainability doi: 10.3390/su10082594 Authors: Ana-Maria Zamfir Cristina Mocanu Adriana Grigorescu Resilience represents the ability of systems and individuals to adapt and overcome the difficulties and challenges they face. Resilient entrepreneurs are those who cope with stressful or adverse situations by relying on both internal and external factors. This article examines the way higher education graduates express entrepreneurial resilience in various national contexts. We analyze the Research into Employment and professional Flexibility (REFLEX) data set that provides information on early career of higher education graduates leaving education in the academic year 1999/2000 in 13 European countries. We study resilience in entrepreneurship by considering both how long higher education graduates succeed to remain in self-employment and the extent to which they re-entry in entrepreneurship after exiting. Survival analyses, logistic and cox regressions indicate important differences in patterns of starting, remaining and returning in self-employment and in factors influencing the retention in entrepreneurship among higher education graduates. It is argued that structural factors, personal characteristics and educational background explain a large amount of variation in resilient entrepreneurship.

Description: Minerals, Vol. 8, Pages 312: Leaching of Primary Copper Sulfide Ore in Chloride-Ferrous Media Minerals doi: 10.3390/min8080312 Authors: Karina E. Salinas Osvaldo Herreros Cynthia M. Torres Copper extraction from primary copper sulfide ore from a typical porphyry copper deposit from Antofagasta, Chile, was investigated after leaching with a chloride-ferrous media at two temperatures. The study focused on whether this chemical leaching system could be applied at an industrial scale. Leaching tests were conducted in columns loaded with approximately 50 kg of agglomerated ore; the ore was first cured for 14 days and then leached for 90 days. The highest copper extraction, 50.23%, was achieved at 32.9 °C with the addition of 0.6 kg of H2SO4 per ton of ore, 0.525 kg of NaCl per ton of ore, and 0.5 kg of FeSO4 per ton of ore. In respect to copper extraction, the most effective variables were temperature and the addition of NaCl.

Description: Sustainability, Vol. 10, Pages 2710: An Analysis of the Energy Consumption Behavior of Scaled, Containerized Web Apps Sustainability doi: 10.3390/su10082710 Authors: Sandro Kreten Achim Guldner Stefan Naumann Containerization is one of the most important topics for modern data centers and web developers. Since the number of containers on one- and multi-node systems is growing, knowledge about the energy consumption behavior of single web-service containers is essential in order to save energy and, of course, money. In this article, we are going to show how the energy consumption behavior of single containerized web services/web apps changes while creating replicas of the service in order to scale and balance the web service.

Description: Sustainability, Vol. 10, Pages 2699: A Framework for Regional Ecological Risk Warning Based on Ecosystem Service Approach: A Case Study in Ganzi, China Sustainability doi: 10.3390/su10082699 Authors: Tian Dong Weihua Xu Hua Zheng Yang Xiao Lingqiao Kong Zhiyun Ouyang Worldwide, most ecosystem services have declined. However, the theoretical and analytical frameworks for the ecological risk assessment of ecosystem services are still lacking. Here a framework for the risk assessment of ecosystem services was developed based on the formation, changes, risk, and management of ecosystem services. The framework was tested in Ganzi, the upstream area of the Yangtze River Basin, for the regional ecological warning of ecosystem services. Ecosystem services in the form of soil retention and sandstorm prevention and ecological risks including soil and wind erosion were modelled. The results showed that with the increase in area and quality of natural vegetation (forest and grassland), the soil retention service and sandstorm prevention service increased by 66.92% and 8.59% between 2000 and 2015, respectively. Correspondingly, the ecological risk of soil erosion decreased by 8.8%, and wind erosion remained stable. Despite the negative impacts from agricultural development on sandstorm prevention, the increase in vegetation and improvement in ecological quality led to a decrease in the ecological risks of soil erosion and sandstorm erosion by improvement of ecosystem services. This research provides a new perspective for ecological risk assessment, as well as direct management information on ecological risks, by incorporating ecosystem services.

Description: Minerals, Vol. 8, Pages 332: Kurchatovite and Clinokurchatovite, Ideally CaMgB2O5: An Example of Modular Polymorphism Minerals doi: 10.3390/min8080332 Authors: Yulia A. Pankova Sergey V. Krivovichev Igor V. Pekov Edward S. Grew Vasiliy O. Yapaskurt Kurchatovite and clinokurchatovite, both of ideal composition CaMgB2O5, from the type localities (Solongo, Buryatia, Russia, and Sayak-IV, Kazakhstan, respectively) have been studied using electron microprobe and single-crystal X-ray diffraction methods. The empirical formulae of the samples are Ca1.01Mg0.87Mn0.11Fe2+0.02B1.99O5 and Ca0.94Mg0.91Fe2+0.10Mn0.04B2.01O5 for kurchatovite and clinokurchatovite, respectively. The crystal structures of the two minerals are similar and based upon two-dimensional blocks arranged parallel to the c axis in kurchatovite and parallel to the a axis in clinokurchatovite. The blocks are built up from diborate B2O5 groups, and Ca2+ and Mg2+ cations in seven- and six-fold coordination, respectively. Detailed analysis of geometrical parameters of the adjacent blocks reveals that symmetrically different diborate groups have different degrees of conformation in terms of the δ angles between the planes of two BO3 triangles sharing a common O atom, featuring two discrete sets of the δ values of ca. 55° (B’ blocks) and 34° (B” blocks). The stacking of the blocks in clinokurchatovite can be presented as …(+B’)(+B”)(+B’)(+B”)… or [(+B’)(+B”)], whereas in kurchatovite it is more complex and corresponds to the sequence …(+B’)(+B”)(+B’)(−B’)(−B”)(−B’)(+B’)(+B”)(+B’)(−B’)(−B”)(−B’)… or [(+B’)(+B”)(+B’)(−B’)(−B”)(−B’)]. The B’:B” ratios for clinokurchatovite and kurchatovite are 1:1 and 2:1, respectively. According to this description, the two minerals cannot be considered as polytypes and their mutual relationship corresponds to the term modular polymorphs. From the viewpoint of information-based measures of structural complexity, clinokurchatovite (IG = 4.170 bits/atom and IG,total = 300.235 bits/cell) is structurally simpler than kurchatovite (IG = 4.755 bits/atom and IG,total = 1027.056 bits/cell). The high structural complexity of kurchatovite can be inferred from the modular character of its structure. The analysis of structural combinatorics in terms of the modular approach allows to construct the whole family of theoretically possible “kurchatovite”-type structures that bear the same structural features common for kurchatovite and clinokurchatovite. However, the crystal structures of the latter minerals are the simplest and are the only ones that have been observed in nature. The absence of other possible structures is remarkable and can be explained by either the maximum-entropy of the least-action fundamental principles.

Description: Minerals, Vol. 8, Pages 331: Textural Characteristics of Noncrystalline Silica in Sinters and Quartz Veins: Implications for the Formation of Bonanza Veins in Low-Sulfidation Epithermal Deposits Minerals doi: 10.3390/min8080331 Authors: Tadsuda Taksavasu Thomas Monecke T. James Reynolds Silica sinters forming at the Wairakei geothermal power plant in New Zealand are composed of noncrystalline opal-A that deposited rapidly from cooling geothermal liquids flashed to atmosphere. The sinter is laminated with alternating layers of variably compacted silicified filamentous microbes encased by chains of fused silica microspheres. Microscopic inspection of bonanza quartz vein samples from the Buckskin National low-sulfidation epithermal precious metal deposit in Nevada showed that colloform bands in these veins exhibit relic microsphere textures similar to those observed in the silica sinters from the Wairakei power plant. The textural similarity suggests that the colloform bands were originally composed of noncrystalline opal-A that subsequently recrystallized to quartz. The colloform bands contain dendrites of electrum and naumannite that must have grown in a yielding matrix of silica microspheres deposited at the same time as the ore minerals, implying that the noncrystalline silica exhibited a gel-like behavior. Quartz bands having other textural characteristics in the crustiform veins lack ore minerals. This suggests that ore deposition and the formation of the colloform bands originally composed of compacted microspheres of noncrystalline silica are genetically linked and that ore deposition within the bonanza veins was only episodic. Supersaturation of silica and precious metals leading to the formation of the colloform bands may have occurred in response to transient flashing of the hydrothermal liquids. Flashing of geothermal liquids may thus represent a key mechanism in the formation of bonanza precious metal grades in low-sulfidation epithermal deposits.

Description: Sensors, Vol. 18, Pages 2534: A Gyroscope Bias Estimation Algorithm Based on Map Specific Information Sensors doi: 10.3390/s18082534 Authors: Tian Tan Ao Peng Junjun Huang Lingxiang Zheng Gang Ou In an inertial navigation system, especially in a pedestrian dead-reckoning system, gyroscope bias can demonstrably reduce positioning accuracy. A novel gyroscope bias estimation algorithm is proposed, which estimates the bias of a gyroscope under any set of angle observations. Moreover, a method for obtaining Euler angles using map corridor information is proposed. The heading information obtained from a map is used to estimate the bias, and the estimated bias is used to correct the trajectories. Experimental results show that it is feasible for the algorithm to estimate the bias of the gyroscope.

Description: Sustainability, Vol. 10, Pages 2732: Sustainable Mineral Resource Management—Insights into the Case of Phosphorus Sustainability doi: 10.3390/su10082732 Authors: Gerald Steiner Bernhard Geissler Although it is among the most abundant elements in Earth’s crust (11th [1]) and water (13th [2]), phosphorus (P) is commonly referred to as “life’s bottleneck”, as “life can multiply until all thephosphorus is gone, and then there is an inexorable halt which nothing can prevent . . . ” [3]. [...]

Description: Sustainability, Vol. 10, Pages 2730: Regime-Switching Determinants for Spreads of Emerging Markets Sovereign Credit Default Swaps Sustainability doi: 10.3390/su10082730 Authors: Ma Deng Ho Tsai Using the Markov regime switching approach, we investigate the dependency of short term sovereign credit default swap (SCDS) spread changes on a nation’s country-specific fundamental factors, local, regional and macroeconomic global factors. We find that the significance of the determinants of SCDS spread changes differ across the two states of our regime-switching model. Specifically, in the good state, the weekly SCDS spread changes are mainly determined by local, regional and fundamental factors; whereas global variables have a stronger influence in the bad regime. In particular, US market returns play a dominant role in influencing the SCDS spread change in the bad state suggesting loss aversion and flight–to–quality behavior of investors. We then examine the cross-sectional differences of the above regime switching effect based on country-specific characters and find that the regime switching effect is associated with a nation’s country-specific characters such as openness, economic size and so forth.

Description: Sustainability, Vol. 10, Pages 2729: Assessment of Postural Load during Melon Cultivation in Mediterranean Greenhouses Sustainability doi: 10.3390/su10082729 Authors: Marta Gómez-Galán José Pérez-Alonso Ángel-Jesús Callejón-Ferre Julián Sánchez-Hermosilla-López Health and safety at work directly influence the development of sustainable agriculture. In the agricultural sector, many farm workers suffer musculoskeletal disorders caused by forced posture. The objective of this research is to assess working postures during melon cultivation in Almería-type greenhouses. The Ovako Working Posture Assessment System (OWAS) has been used with pictures of the tasks. The variables studied by multiple correspondence analysis were as follows: Subtask, Posture code, Back, Arms, Legs, Load, Risk, and Risk combination. The OWAS analysis showed that 47.57% of the postures were assessed as risk category 2, 14.32% as risk category 3, 0.47% as risk category 4, and the rest as risk category 1. Corrective measures should be implemented immediately, as soon as possible, or in the near future, depending on the risks detected.

Description: Sensors, Vol. 18, Pages 2578: An Outlook on Physical and Virtual Sensors for a Socially Interactive Internet Sensors doi: 10.3390/s18082578 Authors: Ngombo Armando André Rodrigues Vasco Pereira Jorge Sá Silva Fernando Boavida The Internet keeps changing at a rapid pace, driven mainly by the emerging concepts and applications that make it aware of the physical world and responsive to user context. The Internet of Things (IoT) concept is quickly giving way to more advanced and highly interactive environments that go well beyond the mere sensing of the physical world. Today, in addition to traditional electronic devices, IoT sensing/actuating includes both software and human-based entities. This paper provides an outlook on the future of sensing/actuating approaches on the Internet at large, which we see increasingly related to all kinds of socially interactive technologies. With these objectives in mind, we propose a taxonomy to deal with the heterogeneity of sensing/actuating approaches in IoT. We also analyse the state-of-the-art of Social Sensing. Finally, we identify open issues and associated research opportunities, the main ones being the integration of all sensing approaches, the combination of social sciences, engineering, and computing as enablers of context-aware, cognitive applications and, last but not least, the unified management of large sets of very heterogeneous sensors/actuators.

Description: Sensors, Vol. 18, Pages 2576: General Signal Model for Multiple-Input Multiple-Output GMTI Radar Sensors doi: 10.3390/s18082576 Authors: Fuyou Li Feng He Zhen Dong Manqing Wu Yongsheng Zhang Multiple-input multiple-output (MIMO) ground moving target indication (GMTI) radar has been studied recently because of its excellent performance. In this paper, a general signal model is established for the MIMO GMTI radar with both fast-time and slow-time waveforms. The general signal model can be used to evaluate the performance of the MIMO GMTI radar with arbitrary waveforms such as the ideal orthogonal, code division multiple access (CDMA), frequency-division multiple access (FDMA), time division multiple access (TDMA), and Doppler division multiple access (DDMA) waveforms. We proposed a range-compensation method to eliminate the range-dependence of the FDMA waveforms. The simulation results indicate that the improved performance of FDMA waveforms is achieved utilizing the range-compensation method.

Description: Sensors, Vol. 18, Pages 2572: Tunable Fabry-Perot Interferometer Designed for Far-Infrared Wavelength by Utilizing Electromagnetic Force Sensors doi: 10.3390/s18082572 Authors: Dong Geon Jung Jun Yeop Lee Jae Keon Kim Daewoong Jung Seong Ho Kong A tunable Fabry-Perot interferometer (TFPI)-type wavelength filter designed for the long-wavelength infrared (LWIR) region is fabricated using micro electro mechanical systems (MEMS) technology and the novel polydimethylsiloxane (PDMS) micro patterning technique. The structure of the proposed infrared sensor consists of a Fabry-Perot interferometer (FPI)-based optical filter and infrared (IR) detector. An amorphous Si-based thermal IR detector is located under the FPI-based optical filter to detect the IR-rays filtered by the FPI. The filtered IR wavelength is selected according to the air etalon gap between reflectors, which is defined by the thickness of the patterned PDMS. The 8 μm-thick PDMS pattern is fabricated on a 3 nm-thick Al layer used as a reflector. The air etalon gap is changed using the electromagnetic force between the permanent magnet and solenoid. The measured PDMS gap height is about 2 μm, ranging from 8 μm to 6 μm, with driving current varying from 0 mA to 600 mA, resulting in a tunable wavelength range of 4 μm. The 3-dB bandwidth (full width at half maximum, FWHM) of the proposed filter is 1.5 nm, while the Free Spectral Range (FSR) is 8 μm. Experimental results show that the proposed TFPI can detect a specific wavelength at the long LWIR region.

Description: Sensors, Vol. 18, Pages 2574: Modeling and Control of a Micro AUV: Objects Follower Approach Sensors doi: 10.3390/s18082574 Authors: Jesus Arturo Monroy-Anieva Cyril Rouviere Eduardo Campos-Mercado Tomas Salgado-Jimenez Luis Govinda Garcia-Valdovinos This work describes the modeling, control and development of a low cost Micro Autonomous Underwater Vehicle (μ-AUV), named AR2D2. The main objective of this work is to make the vehicle to detect and follow an object with defined color by means of the readings of a depth sensor and the information provided by an artificial vision system. A nonlinear PD (Proportional-Derivative) controller is implemented on the vehicle in order to stabilize the heave and surge movements. A formal stability proof of the closed-loop system using Lyapunov’s theory is given. Furthermore, the performance of the μ-AUV is validated through numerical simulations in MatLab and real-time experiments.

Description: Sensors, Vol. 18, Pages 2570: The Sensory Quality and Volatile Profile of Dark Chocolate Enriched with Encapsulated Probiotic Lactobacillus plantarum Bacteria Sensors doi: 10.3390/s18082570 Authors: Milica Mirković Sanja Seratlić Kieran Kilcawley David Mannion Nemanja Mirković Zorica Radulović Cocoa and dark chocolate have a wide variety of powerful antioxidants and other nutrients that can positively affect human health. Probiotic dark chocolate has the potential to be a new product in the growing number of functional foods. In this study, encapsulated potential probiotic Lactobacillus plantarum 564 and commercial probiotic Lactobacillus plantarum 299v were added in the production of dark chocolate. The results show very good survival of probiotic bacteria after production and during storage, reaching 108cfu/g in the first 60 days and over 106cfu/g up to 180 days. No statistically significant difference (p > 0.05) in chemical composition and no major differences in the volatile profiles between control and experimental chocolate samples were observed, indicating no impact of probiotic bacteria on compositional and sensory characteristics of dark chocolate. The sensory evaluation of control and both probiotic dark chocolate samples showed excellent sensory quality after 60 and 180 days of storage, demonstrating that probiotics did not affect aroma, texture and appearance of chocolate. Due to a high viability of bacterial cells and acceptable sensory properties, it can be concluded that encapsulated probiotics Lb. plantarum 564 and Lb. plantarum 299v could be successfully used in the production of probiotic dark chocolate.

Description: Sustainability, Vol. 10, Pages 2785: How Does Project Supervisor Maintain Sustainability of Project Members? A Study from Leadership Perspective Sustainability doi: 10.3390/su10082785 Authors: Han-Sheng Lei Chuan-Fu Lai Chih-Chang Chen Project members’ innovative behavior is crucial to their sustainability and successful implementation of the project. This research develops a conceptual model to explore the effect of project supervisor leadership skills on member’s innovative behavior. The model is examined by a sample of 437 project members in Taiwan. The results show that project supervisors’ emotional healing positively influences members’ innovative behavior through affect-based trust in their supervisor and supervisor conceptual skill has an inverted-U impact on members’ innovative behavior through cognition-based trust in their supervisor. This paper further discusses implications of these conclusions for additional research on the association between leadership skills and innovative behavior.

Description: Sustainability, Vol. 10, Pages 2772: Estimates of Daily PM2.5 Exposure in Beijing Using Spatio-Temporal Kriging Model Sustainability doi: 10.3390/su10082772 Authors: Jinhuang Lin An Zhang Wenhui Chen Mingshui Lin Excessive exposure to ambient (outdoor) air pollution may greatly increase the incidences of respiratory and cardiovascular diseases. Accurate reports of the spatial-temporal distribution characteristics of daily PM2.5 exposure can effectively prevent and reduce the harm caused to humans. Based on the daily average concentration data of PM2.5 in Beijing in May 2014 and the spatio-temporal kriging (STK) theory, we selected the optimal STK fitting model and compared the spatial-temporal prediction accuracy of PM2.5 using the STK method and ordinary kriging (OK) method. We also reveal the spatial-temporal distribution characteristics of the daily PM2.5 exposure in Beijing. The results show the following: (1) The fitting error of the Bilonick model (BM) model which is the smallest (0.00648), and the fitting effect of the prediction model of STK is the best for daily PM2.5 exposure. (2) The cross-examination results show that the STK model (RMSE = 8.90) has significantly lower fitting errors than the OK model (RMSE = 10.70), so its simulation prediction accuracy is higher. (3) According to the interpolation of the STK model, the daily exposure of PM2.5 in Beijing in May 2014 has good continuity in both time and space. The overall air quality is good, and overall the spatial distribution is low in the north and high in the south, with the highest concentration in the southwestern region. (4) There is a certain degree of spatial heterogeneity in the cumulative duration at the good, moderate, and polluted grades of China National Standard. The areas with the longest cumulative duration at the good, moderate and polluted grades are in the north, southeast, and southwest of the study area, respectively.

Description: Sustainability, Vol. 10, Pages 2767: On Decision Makers’ Perceptions of What an Ecological Computer Model is, What It Does, and Its Impact on Limiting Model Acceptance Sustainability doi: 10.3390/su10082767 Authors: Fabio Boschetti Michael Hughes Cheryl Jones Hector Lozano-Montes Environmental decision makers are required to understand complex ecological processes and ecological computer models are designed to facilitate this understanding. A set of interviews reveals three main perceptions affecting senior environmental decision makers’ trust in ecological computer models as decision facilitation tools: an ecological computer model is perceived as (i) a ‘black box’, (ii) processing poorly documented, sparse and out-of-date input data, and (iii) whose sensitivity to model parameters enables manipulation to produce desired outcomes justifying pre-conceived decisions. This leads to lack of trust towards both ecological computer models and model-users, including other scientists and decision makers. Model acceptance appears to depend on the amount, currency and geographical origin of input data. This is at odds with modellers’ communication style, which typically places more emphasis on highlighting the ecological computer model’s features and performance, rather than on describing the input data. Developing ‘big data’ capabilities could deliver the large, real-time, local data that may enhance acceptance. However, the size and complexity of ‘big data’ requires automated pre-processing, using modelling and algorithms that are even more inscrutable than current ecological computer models. Future trust in ecological computer models will likely depend on how this dilemma is resolved, which is likely to require improved communication between modellers and decision makers.

Description: Sustainability, Vol. 10, Pages 2777: Sustainability Assurance in Socially-Sensitive Sectors: A Worldwide Analysis of the Financial Services Industry Sustainability doi: 10.3390/su10082777 Authors: Elies Seguí-Mas Fernando Polo-Garrido Helena María Bollas-Araya Sustainability reporting and assurance have considerably increased in the last decades. Among different sectors, ‘sensitive sectors’ attracted the attention of many academics. However, most of research works were focused only on ‘environmentally-sensitive sectors’. Therefore, after the loss of trust caused by the lack of transparency due to the crisis, ‘socially-sensitive sectors’ as financial services sector needs to strengthen users’ confidence in the credibility of their reported activities. The aim of this paper is to assess assurance practices worldwide in one of the main ‘socially-sensitive sectors’: the financial services sector. We study what factors are associated with adoption of assurance and choice of assurance provider, and whether assurance statements differ across providers. Our results reveal that, compared to the global context, companies operating in the financial services sector are more likely to adopt assurance and to choose accountants as assurance providers. Our findings show that adoption of assurance depends on company size. We also found that companies using the financial services sector supplement are more prone to adopt assurance. Our results also evidence that choice of assurance provider depends on the country and listing status Finally, our research shows a great variability in assurance statements across providers.

Description: Sensors, Vol. 18, Pages 2564: Indirect Measurement of Ground Reaction Forces and Moments by Means of Wearable Inertial Sensors: A Systematic Review Sensors doi: 10.3390/s18082564 Authors: Andrea Ancillao Salvatore Tedesco John Barton Brendan O’Flynn In the last few years, estimating ground reaction forces by means of wearable sensors has come to be a challenging research topic paving the way to kinetic analysis and sport performance testing outside of labs. One possible approach involves estimating the ground reaction forces from kinematic data obtained by inertial measurement units (IMUs) worn by the subject. As estimating kinetic quantities from kinematic data is not an easy task, several models and protocols have been developed over the years. Non-wearable sensors, such as optoelectronic systems along with force platforms, remain the most accurate systems to record motion. In this review, we identified, selected and categorized the methodologies for estimating the ground reaction forces from IMUs as proposed across the years. Scopus, Google Scholar, IEEE Xplore, and PubMed databases were interrogated on the topic of Ground Reaction Forces estimation based on kinematic data obtained by IMUs. The identified papers were classified according to the methodology proposed: (i) methods based on direct modelling; (ii) methods based on machine learning. The methods based on direct modelling were further classified according to the task studied (walking, running, jumping, etc.). Finally, we comparatively examined the methods in order to identify the most reliable approaches for the implementation of a ground reaction force estimator based on IMU data.

Description: Sensors, Vol. 18, Pages 2563: Joint Center Estimation Using Single-Frame Optimization: Part 2: Experimentation Sensors doi: 10.3390/s18082563 Authors: Eric Frick Salam Rahmatalla Human motion capture is driven by joint center location estimates, and error in their estimation can be compounded by subsequent kinematic calculations. Soft tissue artifact (STA), the motion of tissue relative to the underlying bones, is a primary cause of error in joint center calculations. A method for mitigating the effects of STA, single-frame optimization (SFO), was introduced and numerically verified in Part 1 of this work, and the purpose of this article (Part 2) is to experimentally compare the results of SFO with a marker-based solution. The experimentation herein employed a single-degree-of-freedom pendulum to simulate human joint motion, and the effects of STA were simulated by affixing the inertial measurement unit to the pendulum indirectly through raw, vacuum-sealed meat. The inertial sensor was outfitted with an optical marker adapter so that its location could be optically determined by a camera-based motion-capture system. During the motion, inertial effects and non-rigid attachment of the inertial sensor caused the simulated STA to manifest via unrestricted motion (six degrees of freedom) relative to the rigid pendulum. The redundant inertial and optical instrumentation allowed a time-varying joint center solution to be determined both by optical markers and by SFO, allowing for comparison. The experimental results suggest that SFO can achieve accuracy comparable to that of state-of-the-art joint center determination methods that use optical skin markers (root mean square error of 7.87–37.86 mm), and that the time variances of the SFO solutions are correlated (r =  0.58–0.99) with the true, time-varying joint center solutions. This suggests that SFO could potentially help to fill a gap in the existing literature by improving the characterization and mitigation of STA in human motion capture.

Description: Sensors, Vol. 18, Pages 2562: A Real-Time Imaging Algorithm Based on Sub-Aperture CS-Dechirp for GF3-SAR Data Sensors doi: 10.3390/s18082562 Authors: Guang-Cai Sun Yanbin Liu Mengdao Xing Shiyu Wang Liang Guo Jun Yang Conventional synthetic aperture radar (SAR) imaging algorithms usually require a period of time to process data that is longer than the time it takes to record one synthetic aperture or that corresponding to an adequate azimuth resolution. That is to say, the real-time processing system is idle during the long data recording time and the utilization of computational resources is low. To deal with this problem, a real-time imaging algorithm based on sub-aperture chirp scaling dechirp (CS-dechirp) is proposed in this paper. With CS-dechirp, the sub-aperture data could be processed to form an image with relatively low resolution. Subsequently, a few low-resolution images are generated as longer azimuth data are recorded. At the stage of full-resolution image generation, a coherent combination method for the low-resolution complex-value images is developed. As the low-resolution complex-value images are coherently combined one by one, the resolution is gradually improved and the full-resolution image is finally obtained. The results of a simulation and real data from the GF3-SAR validate the effectiveness of the proposed algorithm.

Description: Sustainability, Vol. 10, Pages 2762: Technological Entrepreneurship: How does Environmental Turbulence Impact upon Collaboration Risk? Sustainability doi: 10.3390/su10082762 Authors: Iwona Staniec The aim of this paper is to identify the impact of environmental turbulence on the risk of cooperation in technological entrepreneurship. Multidimensional factors such as the risk of cooperation, environmental turbulence, and the reaction to operationalized changes were selected during the literature review, and were subjected to empirical verification on a 304 element sample of SMEs, which are implementing technology entrepreneurship. The study used a questionnaire interview technique conducted directly in the company, and the research tool was a specially prepared questionnaire. Because of the multidimensional character of the studied variables, structural modelling was chosen. In addition, the influence of selected mediators and moderators on the relationship between the turbulence of the environment and the risk of cooperation in technological entrepreneurship was examined. The article has been divided into five main sections. The first section constitutes the introduction to the deliberations. A detailed review of the literature, taking into account the principles of operationalization of each of the presented variables, is discussed in the second section. The methodology used is then presented. In the next section of the paper, the results of the research are presented and then a broad discussion of these results is undertaken. The last section is a summary of the conducted research and its limitations. Knowledge about the antecedents of cooperation risk allows for the minimization of the presence of adverse phenomena, while knowledge of the directions of their impact greatly enriches the experience in the management of this type of relationship. The presented research may contribute to the construction of a rational model of the cooperation risk management process, in particular, in the case of adopting resources existing within the organization.

Description: Minerals, Vol. 8, Pages 337: The Compressive Strength and Microstructure of Alkali-Activated Binary Cements Developed by Combining Ceramic Sanitaryware with Fly Ash or Blast Furnace Slag Minerals doi: 10.3390/min8080337 Authors: Juan Cosa Lourdes Soriano María Victoria Borrachero Lucía Reig Jordi Payá José María Monzó The properties of a binder developed by the alkali-activation of a single waste material can improve when it is blended with different industrial by-products. This research aimed to investigate the influence of blast furnace slag (BFS) and fly ash (FA) (0–50 wt %) on the microstructure and compressive strength of alkali-activated ceramic sanitaryware (CSW). 4 wt % Ca(OH)2 was added to the CSW/FA blended samples and, given the high calcium content of BFS, the influence of BFS was analyzed with and without adding Ca(OH)2. Mortars were used to assess the compressive strength of the blended cements, and their microstructure was investigated in pastes by X-ray diffraction, thermogravimetry, and field emission scanning electron microscopy. All the samples were cured at 20 °C for 28 and 90 days and at 65 °C for 7 days. The results show that the partial replacement of CSW with BFS or FA allowed CSW to be activated at 20 °C. The CSW/BFS systems exhibited better mechanical properties than the CSW/FA blended mortars, so that maximum strength values of 54.3 MPa and 29.4 MPa were obtained in the samples prepared with 50 wt % BFS and FA, respectively, cured at 20 °C for 90 days.

Description: Sensors, Vol. 18, Pages 2589: Design of Novel Ceramic Preconcentrator and Integration in Gas Chromatographic System for Detection of Ethylene Gas from Ripening Bananas Sensors doi: 10.3390/s18082589 Authors: Nayyer Zaidi Muhammad Tahir Micheal Vellekoop Walter Lang In this paper, a novel ceramic preconcentrator is manufactured using aluminum nitride (ALN) ceramics. The preconcentrator consists of a heater, a preconcentrator body, a gas inlet and a gas outlet. The adsorption material, Carbosieve SII, is loaded into the preconcentrator. The preconcentrator is integrated with a previously developed micro gas chromatographic system filled with ethylene. When operated, adequate ethylene gas is adsorbed into the preconcentrator. The application of heat pulse also successfully desorbs the ethylene gas. Tests are conducted with ethylene gas at concentrations of 10 ppm, 5 ppm and 2.5 ppm and 400 ppb, respectively. The system is also tested with ethylene gas from ripening bananas over a period of three days. No interference signal is observed in the chromatogram because of other ripening gases (e.g., carbon dioxide, oxygen, alcohol) and humidity. A detection limit of 25 ppb is realized with this system. The developed preconcentrator has several applications, e.g., in food industry and environmental monitoring.

Description: Sustainability, Vol. 10, Pages 2802: Bi-Objective Scheduling Optimization for Discrete Time/Cost Trade-Off in Projects Sustainability doi: 10.3390/su10082802 Authors: Hongbo Li Zhe Xu Wenchao Wei In sustainable project management, time and cost are two critical factors affecting the success of a project. Time/cost trade-offs in projects accelerate the execution of some activities by increasing the amount of non-renewable resources committed to them and therefore shorten the project duration. The discrete time/cost trade-off problem (DTCTP) has been extensively studied during the past 20 years. However, due to its complexity, the DTCTP—especially the DTCTP curve problem (DTCTP-C)—has only been solved for relatively small instances. To the best of our knowledge, there is no computational performance analysis for solving the DTCTP-C on large project instances with up to 500 activities. This paper aims to fill this gap. We present two bi-objective heuristic algorithms for the DTCTP-C where both project duration and cost are minimized. The objective is to obtain a good appropriate efficient set for the large-scale instances. The first algorithm is based on the non-dominated sorting genetic algorithm II (NSGA-II) and uses a specially designed critical path-based crossover operator. The second algorithm is a steepest descent heuristic which generates efficient solutions by iteratively solving the DTCTP with different deadlines. Computational experiments are conducted to validate the proposed algorithms on a large set of randomly generated problem instances.

Description: Sustainability, Vol. 10, Pages 2800: A Framework for Spatiotemporal Analysis of Regional Economic Agglomeration Patterns Sustainability doi: 10.3390/su10082800 Authors: Rui Jin Jianya Gong Min Deng Yiliang Wan Xuexi Yang Understanding regional economic agglomeration patterns is critical for sustainable economic development, urban planning and proper utilization of regional resources. Taking Guangdong Province of China as the study area, this paper introduces a comprehensive research framework for analyzing regional economic agglomeration patterns and understanding their spatiotemporal characteristics. First, convergence and autocorrelation methods are applied to understand the economic spatial patterns. Then, the intercity spatial interaction model (ISIM) is proposed to measure the strength of interplay among cities, and social network analysis (SNA) based on the ISIM is utilized, which is designed to reveal the network characteristics of economic agglomerations. Finally, we perform a spatial panel data analysis to comprehensively interpret the influences of regional economic agglomerations. The results indicate that from 2001 to 2016, the economy in Guangdong showed a double-core/peripheral pattern of convergence, with strengthened intercity interactions. The strength and external spillover effects of Guangzhou and Shenzhen enhanced, while Foshan and Dongguan had relatively strong absorptive abilities. Moreover, expanding regional communication and cooperation is key to enhancing vigorous economic agglomerations and regional network ties in Guangdong by spatial panel data analysis. Our results show that this is a suitable method of reflecting regional economic agglomeration process and its spatiotemporal pattern.

Description: Sustainability, Vol. 10, Pages 2798: Bringing the Community Back: A Case Study of the Post-Earthquake Heritage Restoration in Kathmandu Valley Sustainability doi: 10.3390/su10082798 Authors: Stelios Lekakis Shobhit Shakya Vasilis Kostakis Heritage preservation is a resource-intensive activity nested among other processes in the public administration, related to identity building and touristic product enhancement. Strategies and schemata associated with heritage preservation sprang in the western world after WWII and they have been adapted, in the form of ‘heritage management’, in various contexts with questionable effectiveness regarding sustainability. Our paper discusses the case of the post-earthquake cultural, social and political landscape of the World Heritage Site of Kathmandu valley in Nepal. By reviewing the bibliography and drawing upon various case studies of post-earthquake heritage restoration, we focus on the traditional ways of managing human and cultural resources in the area as related to the modern national heritage management mechanism. We also examine how traditional practices, re-interpreted into a modern context, can point towards inclusive and sustainable forms of collaboration based on the commons. We shed light on the elements of an emerging management system that could protect the vulnerable monuments through community participation, adapted to the challenging realities of the Nepalese heritage and its stakeholders.

Description: Sustainability, Vol. 10, Pages 2792: The Causal Nexus between Oil Prices, Interest Rates, and Unemployment in Norway Using Wavelet Methods Sustainability doi: 10.3390/su10082792 Authors: Hyunjoo Kim Karlsson Yushu Li Ghazi Shukur This paper applies wavelet multi-resolution analysis (MRA), combined with two types of causality tests, to investigate causal relationships between three variables: real oil price, real interest rate, and unemployment in Norway. Impulse response functions were also utilised to examine effects of innovation in one variable on the other variables. We found that causal relations between the variables tend to be stronger as the wavelet time scale increases; specifically, there were no causal relationships between the variables at the lowest time scales of one to three months. A causal relationship between unemployment rate and interest rate was observed during the period of two quarters to two years, during which time a feedback mechanism was also detected between unemployment and interest rate. Causal relationships between oil price and both interest rate and unemployment were observed at the longest time scale of eight quarters. In conjunction with Granger causality analysis, impulse response functions showed that unemployment rates in Norway respond negatively to oil price shocks around two years after the shocks occur. As an oil exporting country, increases (or decreases) in oil prices reduce (or increase) unemployment in Norway under a time horizon of about two years; previous studies focused on oil importing economies have generally found the inverse to be true. Unlike most studies in this field, we decomposed the implicit aggregation for all time scales by applying MRA with a focus on the Norwegian economy. Thus, one main contribution of this paper is that we unveil and systematically distinguish the nature of the time-scale dependent relationship between real oil price, real interest rate, and unemployment using wavelet decomposition.

Description: Sustainability, Vol. 10, Pages 2795: Tasty or Sustainable? The Effect of Product Sensory Experience on a Sustainable New Food Product: An Application of Discrete Choice Experiments on Chianina Tinned Beef Sustainability doi: 10.3390/su10082795 Authors: Biancamaria Torquati Tiziano Tempesta Daniel Vecchiato Sonia Venanzi This study aims to contribute to the existing literature by verifying whether the degree of liking of a new food product influences people’s preferences and willingness to pay from a discrete choice experiment when dealing with sustainable food products. To this purpose, we considered the case study of the introduction into the Italian market of a new food product: tinned Chianina meat. Among the attributes considered for this new product, two in particular were related to sustainability: organic breeding and the preservation of a traditional rural landscape. Half of the respondents underwent a sensory test before taking part in the hypothetical market (discrete choice experiment), while the remaining were administered the tests in reverse order. Tasting the product before the discrete choice experiment did not produce different willingness to pay (WTP) parameters as estimated by a taste factor interaction. However, separating the respondents into those who liked or disliked the product in the tasting condition revealed differences in willingness to pay results. The preferences are different for more than 50% of the attributes considered, and the magnitude of this difference is quite relevant. The WTP for one well known and certified sustainability related attribute—organic breeding—was not affected by the liking, while, for the other—the preservation of a traditional rural landscape—the effect of liking decreases the WTP. As a consequence, we suggest that tasting and liking studies should be routinely coupled with discrete choice studies when analyzing the introduction of new food products, especially when considering sustainable attributes in the experimental design. In the case of organic products where the expectations about taste are higher, neglecting to consider their sensory perception, along with the other discrete choice experiment attributes, could seriously undermine their long lasting success on the market.

Description: Sustainability, Vol. 10, Pages 2797: The Cause and Evolution of Urban Street Vitality under the Time Dimension: Nine Cases of Streets in Nanjing City, China Sustainability doi: 10.3390/su10082797 Authors: Xiaodong Xu Xinhan Xu Peng Guan Yu Ren Wei Wang Ning Xu Street vitality is associated with a comfortable human-based public environment and urban sustainability. In most current studies, street vitality is assessed considering single or multi factors; however, the impact of time dimension is ignored. This study selects nine different year-built streets in old, main, and new urban areas, in Nanjing, China, proposes a framework to assess street vitality considering the different time dimensions and selects the following factors: street form, including building density, continuity, and height-width; street business type, including store density, function density, and permeation rate; and street accessibility, including location, the number of entrances/exits, transportation, and walkability. After calculating the values of the subfactors, a ranking method was applied to assign the ranking of impact of all factors for a comprehensive analysis. The results showed that Pipa Street, Wufu Street in a main urban area, and Hongmiao Street had the highest street vitality and the highest rankings of almost all the factors. Street vitality in different periods demonstrated that street vitality in new urban areas is lower compared with old and main urban areas.

Description: Sensors, Vol. 18, Pages 2580: Evaluation of Water Indices for Surface Water Extraction in a Landsat 8 Scene of Nepal Sensors doi: 10.3390/s18082580 Authors: Tri Dev Acharya Anoj Subedi Dong Ha Lee Accurate and frequent updates of surface water have been made possible by remote sensing technology. Index methods are mostly used for surface water estimation which separates the water from the background based on a threshold value. Generally, the threshold is a fixed value, but can be challenging in the case of environmental noise, such as shadow, forest, built-up areas, snow, and clouds. One such challenging scene can be found in Nepal where no such evaluation has been done. Taking that in consideration, this study evaluates the performance of the most widely used water indices: Normalized Difference Vegetation Index (NDVI), Normalized Difference Water Index (NDWI), Modified NDWI (MNDWI), and Automated Water Extraction Index (AWEI) in a Landsat 8 scene of Nepal. The scene, ranging from 60 m to 8848 m, contains various types of water bodies found in Nepal with different forms of environmental noise. The evaluation was conducted based on measures from a confusion matrix derived using validation points. Comparing visually and quantitatively, not a single method was able to extract surface water in the entire scene with better accuracy. Upon selecting optimum thresholds, the overall accuracy (OA) and kappa coefficient (kappa) was improved, but not satisfactory. NDVI and NDWI showed better results for only pure water pixels, whereas MNDWI and AWEI were unable to reject snow cover and shadows. Combining NDVI with NDWI and AWEI with shadow improved the accuracy but inherited the NDWI and AWEI characteristics. Segmenting the test scene with elevations above and below 665 m, and using NDVI and NDWI for detecting water, resulted in an OA of 0.9638 and kappa of 0.8979. The accuracy can be further improved with a smaller interval of categorical characteristics in one or multiple scenes.

Description: Sensors, Vol. 18, Pages 2581: The Shared Bicycle and Its Network—Internet of Shared Bicycle (IoSB): A Review and Survey Sensors doi: 10.3390/s18082581 Authors: Shu Shen Zhao-Qing Wei Li-Juan Sun Yang-Qing Su Ru-Chuan Wang Han-Ming Jiang With the expansion of Intelligent Transport Systems (ITS) in smart cities, the shared bicycle has developed quickly as a new green public transportation mode, and is changing the travel habits of citizens heavily across the world, especially in China. The purpose of the current paper is to provide an inclusive review and survey on shared bicycle besides its benefits, history, brands and comparisons. In addition, it proposes the concept of the Internet of Shared Bicycle (IoSB) for the first time, as far as we know, to find a feasible solution for those technical problems of the shared bicycle. The possible architecture of IoSB in our opinion is presented, as well as most of key IoT technologies, and their capabilities to merge into and apply to the different parts of IoSB are introduced. Meanwhile, some challenges and barriers to IoSB’s implementation are expressed thoroughly too. As far as the advice for overcoming those barriers be concerned, the IoSB’s potential aspects and applications in smart city with respect to technology development in the future provide another valuable further discussion in this paper.

Description: Sustainability, Vol. 10, Pages 2799: A Definition and Theoretical Review of the Circular Economy, Value Creation, and Sustainable Business Models: Where Are We Now and Where Should Research Move in the Future? Sustainability doi: 10.3390/su10082799 Authors: Tom Lahti Joakim Wincent Vinit Parida This paper contains a theory review of value creation and the implementation of next-generation sustainable business models to profit in the circular economy. While previous research has pointed to the influence of society and regulatory policy on companies’ ability to address larger sustainability concerns and to change their ways of working, the field suffers from little theoretical guidance outlining how undertake circular business mode transformation in practice. By reviewing the field’s main theories, we illustrate significant implications for how future research can study profitability and competitiveness in the circular economy. This paper introduces the central components of circular business models and discusses links to contingency theory, transaction cost theory, resource-based theory, theory on networks and industrial economics, and agency theory. Understanding the circular economy and the ways companies can compete in the circular economy based on these theories is important for establishing important new research directions for scholars of sustainable business and circular business models.

Description: Sensors, Vol. 18, Pages 1915: Measurement Uncertainty Calculations for pH Value Obtained by an Ion-Selective Electrode Sensors doi: 10.3390/s18061915 Authors: Józef Wiora Alicja Wiora An assessment of measurement uncertainty is a task, which has to be the final step of every chemical assay. Apart from a commonly applied typical assessment method, Monte Carlo (MC) simulations may be used. The simulations are frequently performed by a computer program, which has to be written, and therefore some programming skills are required. It is also possible to use a commonly known spreadsheet and perform such simulations without writing any code. Commercial programs dedicated for the purpose are also available. In order to show the advantages and disadvantages of the ways of uncertainty evaluation, i.e., the typical method, the MC method implemented in a program and in a spreadsheet, and commercial programs, a case of pH measurement after two-point calibration is considered in this article. The ways differ in the required mathematical transformations, degrees of software usage, the time spent for the uncertainty calculations, and cost of software. Since analysts may have different mathematical and coding skills and practice, it is impossible to point out the best way of uncertainty assessment—all of them are just as good and give comparable assessments.

Description: Sensors, Vol. 18, Pages 1916: Automatic Railway Traffic Object Detection System Using Feature Fusion Refine Neural Network under Shunting Mode Sensors doi: 10.3390/s18061916 Authors: Tao Ye Baocheng Wang Ping Song Juan Li Many accidents happen under shunting mode when the speed of a train is below 45 km/h. In this mode, train attendants observe the railway condition ahead using the traditional manual method and tell the observation results to the driver in order to avoid danger. To address this problem, an automatic object detection system based on convolutional neural network (CNN) is proposed to detect objects ahead in shunting mode, which is called Feature Fusion Refine neural network (FR-Net). It consists of three connected modules, i.e., the depthwise-pointwise convolution, the coarse detection module, and the object detection module. Depth-wise-pointwise convolutions are used to improve the detection in real time. The coarse detection module coarsely refine the locations and sizes of prior anchors to provide better initialization for the subsequent module and also reduces search space for the classification, whereas the object detection module aims to regress accurate object locations and predict the class labels for the prior anchors. The experimental results on the railway traffic dataset show that FR-Net achieves 0.8953 mAP with 72.3 FPS performance on a machine with a GeForce GTX1080Ti with the input size of 320 × 320 pixels. The results imply that FR-Net takes a good tradeoff both on effectiveness and real time performance. The proposed method can meet the needs of practical application in shunting mode.

Description: Sustainability, Vol. 10, Pages 1975: Sustainable Legitimacy: Chinese Government Inspections and Public Approval of Village Leadership Sustainability doi: 10.3390/su10061975 Authors: Jinrui Xi Inspections to villages are an important mechanism for the Chinese government to gain and retain its ruling legitimacy. However, whether inspections have been effectively utilized for that designated purpose of sustainable governance remains less clear. We know very little about how the Chinese government employs inspections to boost its public approval. This study sets out to examine that effect, contending that inspections to Chinese villages significantly boost the public approval of village leaderships by promoting the governing efficacy of village leaders. The consistent practice of inspections results in a sustained level of public support for the Chinese government. This causal relationship between inspections and public approval holds, first, by improving village social welfare and economic development, and second, by securing for village leaders essential political and financial support from higher authorities to better represent villagers’ interests and mediate conflicts among villagers. Using data of 961 randomly selected villages across China, the empirical analysis shows that Chinese government inspections significantly boost villagers’ approval regarding their village leaders.

Description: Sensors, Vol. 18, Pages 1910: Data Fusion Architectures for Orthogonal Redundant Inertial Measurement Units Sensors doi: 10.3390/s18061910 Authors: Eric Gagnon Alexandre Vachon Yanick Beaudoin This work looks at the exploitation of large numbers of orthogonal redundant inertial measurement units. Specifically, the paper analyses centralized and distributed architectures in the context of data fusion algorithms for those sensors. For both architectures, data fusion algorithms based on Kalman filter are developed. Some of those algorithms consider sensors location, whereas the others do not, but all estimate the sensors bias. A fault detection algorithm, based on residual analysis, is also proposed. Monte-Carlo simulations show better performance for the centralized architecture with an algorithm considering sensors location. Due to a better estimation of the sensors bias, the latter provides the most precise and accurate estimates and the best fault detection. However, it requires a much longer computational time. An analysis of the sensors bias correlation is also done. Based on the simulations, the biases correlation has a small effect on the attitude rate estimation, but a very significant one on the acceleration estimation.

Description: Minerals, Vol. 8, Pages 250: Effect of Ammonium Chloride on the Efficiency with Which Copper Sulfate Activates Marmatite: Change in Solution Composition and Regulation of Surface Composition Minerals doi: 10.3390/min8060250 Authors: Shengdong Zhang Dongxia Feng Xiong Tong Bo Yang Xian Xie Zinc sulfide minerals are the primary choice for zinc extraction and marmatite is one of the two most common zinc sulphide minerals (sphalerite and marmatite), therefore it is of great significance to study and optimize the flotation of marmatite. To improve the activation of copper sulfate on marmatite, a method involving the addition of ammonium chloride is devised. The method has been proven to be an effective way of improving the activation efficiency of copper sulfate towards marmatite under alkaline conditions. The strengthening mechanism was studied using micro-flotation, adsorption test, X-ray photoelectron spectroscopy, and by analyzing changes in solution composition. Flotation test results show that the activation effect of the copper sulfate towards marmatite is enhanced with the addition of ammonium chloride. According to the results of the adsorption measurements and X-ray photoelectron spectroscopy analysis, when the marmatite surface is activated using copper sulfate with added ammonia chloride, it adsorbs more copper sulfide and less copper hydroxide and zinc hydroxide. These changes in surface composition are believed to occur via the following process: NH3(aq) promotes the dissolution of zinc hydroxide and then facilitates the conversion of surface copper hydroxide to copper sulfide. In addition, the occurrence of Cu(NH3)n2+ can promote the adsorption of copper ions (Cu2+ can be stored as Cu(NH3)n2+ via complexation, and then, when the concentration of copper ions decreases, Cu2+ can be released through the decompositionof Cu(NH3)n2+. Hence, the copper ion concentration can be maintained and this can facilitate the adsorption of Cu2+ on marmatite). Based on a comprehensive analysis of all our results, we propose that adding ammonium chloride to the copper sulfate changes the solution components (i.e., the presence of NH3(aq) and Cu(NH3)n2+) and then regulates the surface composition of marmatite. The change in surface composition improves the hydrophobicity of mineral surface and this leads to an improvement in activation of marmatite.

Description: Sensors, Vol. 18, Pages 1898: Coastline Detection with Gaofen-3 SAR Images Using an Improved FCM Method Sensors doi: 10.3390/s18061898 Authors: Meng An Qian Sun Jun Hu Yuqi Tang Ziwei Zhu The coastline detection is one of the main applications of the Gaofen-3 satellite in the ocean field. However, the capability of Gaofen-3 SAR image in coastline detection has not yet been validated. In this paper, two Gaofen-3 SAR images, acquired in 2016, were used to extract the coastlines of the regions of Bohai and Taihu in China, respectively. The classical Fuzzy C-means (FCM) method was used in the coastline detection, but had been improved by combining the Wavelet decomposition algorithm to better suppress the inherent speckle noises of SAR image. Coastline detection results obtained from two Sentinel-1 SAR images acquired on the same regions were compared with those of the Gaofen-3 images. By using the manually delineated coastlines as the standards in the qualitative evaluations, improvements of about 12.0%, 8.3%, 23.8%, and 9.4% can be achieved by the improved FCM method with respect to the indicators of mean, RMSE, PGSD, and P90%, respectively; demonstrating that the Gaofen-3 data is superior to the Sentinel-1 data in the detection of coastline.

Description: Sensors, Vol. 18, Pages 1897: An IBeacon-Based Location System for Smart Home Control Sensors doi: 10.3390/s18061897 Authors: Qinghe Liu Xinshuang Yang Lizhen Deng Indoor location and intelligent control system can bring convenience to people’s daily life. In this paper, an indoor control system is designed to achieve equipment remote control by using low-energy Bluetooth (BLE) beacon and Internet of Things (IoT) technology. The proposed system consists of five parts: web server, home gateway, smart terminal, smartphone app and BLE beacons. In the web server, fingerprint matching based on RSSI stochastic characteristic and posture recognition model based on geomagnetic sensing are used to establish a more efficient equipment control system, combined with Pedestrian Dead Reckoning (PDR) technology to improve the accuracy of location. A personalized menu of remote “one-click” control is finally offered to users in a smartphone app. This smart home control system has been implemented by hardware, and precision and stability tests have been conducted, which proved the practicability and good user experience of this solution.