ALBERT

Description: Energies, Vol. 11, Pages 82: Simultaneous Production of Transformer Insulating Oil and Value-Added Glycerol Carbonates from Soybean Oil by Lipase-Catalyzed Transesterification in Dimethyl Carbonate Energies doi: 10.3390/en11010082 Authors: Keon Kim Eun Lee Fatty acid methyl esters (FAMEs), as a transformer insulating oil, and value-added glycerol derivatives were simultaneously synthesized from soybean oil by transesterification using Lipozyme 435 in dimethyl carbonate (DMC). The conversion of transformer insulating oil and glycerol derivatives reached 92% and 72%, respectively, under optimum conditions (DMC-to-oil molar ratio of 4.5:1 with 0.5 v/v % water and 15 wt. % Lipozyme 435 at 70 °C) in one-pot batch reactions. The purified transformer insulating oil possessed a dielectric breakdown voltage of 82.0 kV, which is sufficiently high for transformer insulation oil applications. Other properties such as density, dielectric breakdown voltage, and viscosity were comparable or superior to those of mineral oil, confirming that achieved material could be used as an alternative transformer insulating oil. Additionally, the glycerol was simultaneously converted into glycerol derivatives, which can be utilized as ingredients for cosmetics or monomers for bio-based plastics. This study clearly demonstrates that transformer insulating oil and value-added glycerol derivatives were simultaneously produced based on the zero-waste utilization of soybean oil.

Description: Materials, Vol. 11, Pages 56: Synthesis, Characterization, and Electrochemical Behavior of LiMnxFe(1−x)PO4 Composites Obtained from Phenylphosphonate-Based Organic-Inorganic Hybrids Materials doi: 10.3390/ma11010056 Authors: Alessandro Dell’Era Mauro Pasquali Elvira Bauer Stefano Vecchio Ciprioti Francesca Scaramuzzo Carla Lupi The synthesis of organic-inorganic hybrid compounds based on phenylphosphonate and their use as precursors to form LiMnxFe(1−x)PO4 composites containing carbonaceous substances with sub-micrometric morphology are presented. The experimental procedure includes the preliminary synthesis of Fe2+ and/or Mn2+ phenylphosphonates with the general formula Fe(1−x)Mnx[(C6H5PO3)(H2O)] (with 0 < x < 1), which are then mixed at different molar ratios with lithium carbonate. In this way the carbon, obtained from in situ partial oxidation of the precursor organic part, coats the LiMnxFe(1−x)PO4 particles. After a structural and morphological characterization, the electrochemical behavior of lithium iron manganese phosphates has been compared to the one of pristine LiFePO4 and LiMnPO4, in order to evaluate the doping influence on the material.

Description: Sensors, Vol. 18, Pages 91: A Review of Oil Spill Remote Sensing Sensors doi: 10.3390/s18010091 Authors: Merv Fingas Carl Brown The technical aspects of oil spill remote sensing are examined and the practical uses and drawbacks of each technology are given with a focus on unfolding technology. The use of visible techniques is ubiquitous, but limited to certain observational conditions and simple applications. Infrared cameras offer some potential as oil spill sensors but have several limitations. Both techniques, although limited in capability, are widely used because of their increasing economy. The laser fluorosensor uniquely detects oil on substrates that include shoreline, water, soil, plants, ice, and snow. New commercial units have come out in the last few years. Radar detects calm areas on water and thus oil on water, because oil will reduce capillary waves on a water surface given moderate winds. Radar provides a unique option for wide area surveillance, all day or night and rainy/cloudy weather. Satellite-carried radars with their frequent overpass and high spatial resolution make these day–night and all-weather sensors essential for delineating both large spills and monitoring ship and platform oil discharges. Most strategic oil spill mapping is now being carried out using radar. Slick thickness measurements have been sought for many years. The operative technique at this time is the passive microwave. New techniques for calibration and verification have made these instruments more reliable.

Description: Sensors, Vol. 18, Pages 92: Wireless sEMG System with a Microneedle-Based High-Density Electrode Array on a Flexible Substrate Sensors doi: 10.3390/s18010092 Authors: Minjae Kim Gangyong Gu Kyoung Cha Dong Kim Wan Chung Surface electromyography (sEMG) signals reflect muscle contraction and hence, can provide information regarding a user’s movement intention. High-density sEMG systems have been proposed to measure muscle activity in small areas and to estimate complex motion using spatial patterns. However, conventional systems based on wet electrodes have several limitations. For example, the electrolyte enclosed in wet electrodes restricts spatial resolution, and these conventional bulky systems limit natural movements. In this paper, a microneedle-based high-density electrode array on a circuit integrated flexible substrate for sEMG is proposed. Microneedles allow for high spatial resolution without requiring conductive substances, and flexible substrates guarantee stable skin–electrode contact. Moreover, a compact signal processing system is integrated with the electrode array. Therefore, sEMG measurements are comfortable to the user and do not interfere with the movement. The system performance was demonstrated by testing its operation and estimating motion using a Gaussian mixture model-based, simplified 2D spatial pattern.

Description: IJERPH, Vol. 15, Pages 51: Influence of Land Use and Point Source Pollution on Water Quality in a Developed Region: A Case Study in Shunde, China International Journal of Environmental Research and Public Health doi: 10.3390/ijerph15010051 Authors: Wenjing Bo Xiaoke Wang Qianqian Zhang Yi Xiao Zhiyun Ouyang To design and implement policy to manage water quality, it is important to investigate land use and possible sources of pollution. In this study, using Pearson regression analysis, redundancy analysis and multiple regression analysis, we assess the influence of land use and point sources on water quality in the river system in Shunde district in 2000 and 2010. The results show that water quality was related positively with water surface but negatively with impervious and urban greening area. Additionally, water quality was related negatively to point source emissions of chemical oxygen demand (COD) and ammonium-nitrogen (NH4-N). The total explanatory power of spatial variation of water quality was improved from 43.4% to 60.0% in 2000 and from 31.3% to 57.8% in 2010, respectively, when the influence of point sources was added into redundancy analysis between water quality and land use. Thus, both land use management and point source pollution control should be considered for improving river water quality.

Description: IJERPH, Vol. 15, Pages 52: Antibiotic Resistance of Acinetobacter spp. Isolates from the River Danube: Susceptibility Stays High International Journal of Environmental Research and Public Health doi: 10.3390/ijerph15010052 Authors: Clemens Kittinger Alexander Kirschner Michaela Lipp Rita Baumert Franz Mascher Andreas Farnleitner Gernot Zarfel Acinetobacter spp. occur naturally in many different habitats, including food, soil, and surface waters. In clinical settings, Acinetobacter poses an increasing health problem, causing infections with limited to no antibiotic therapeutic options left. The presence of human generated multidrug resistant strains is well documented but the extent to how widely they are distributed within the Acinetobacter population is unknown. In this study, Acinetobacter spp. were isolated from water samples at 14 sites of the whole course of the river Danube. Susceptibility testing was carried out for 14 clinically relevant antibiotics from six different antibiotic classes. Isolates showing a carbapenem resistance phenotype were screened with PCR and sequencing for the underlying resistance mechanism of carbapenem resistance. From the Danube river water, 262 Acinetobacter were isolated, the most common species was Acinetobacter baumannii with 135 isolates. Carbapenem and multiresistant isolates were rare but one isolate could be found which was only susceptible to colistin. The genetic background of carbapenem resistance was mostly based on typical Acinetobacter OXA enzymes but also on VIM-2. The population of Acinetobacter (baumannii and non-baumannii) revealed a significant proportion of human-generated antibiotic resistance and multiresistance, but the majority of the isolates stayed susceptible to most of the tested antibiotics.

Description: Remote Sensing, Vol. 10, Pages 53: Issues with Large Area Thematic Accuracy Assessment for Mapping Cropland Extent: A Tale of Three Continents Remote Sensing doi: 10.3390/rs10010053 Authors: Kamini Yadav Russell Congalton Accurate, consistent and timely cropland information over large areas is critical to solve food security issues. To predict and respond to food insecurity, global cropland products are readily available from coarse and medium spatial resolution earth observation data. However, while the use of satellite imagery has great potential to identify cropland areas and their specific types, the full potential of this imagery has yet to be realized due to variability of croplands in different regions. Despite recent calls for statistically robust and transparent accuracy assessment, more attention regarding the accuracy assessment of large area cropland maps is still needed. To conduct a valid assessment of cropland maps, different strategies, issues and constraints need to be addressed depending upon various conditions present in each continent. This study specifically focused on dealing with some specific issues encountered when assessing the cropland extent of North America (confined to the United States), Africa and Australia. The process of accuracy assessment was performed using a simple random sampling design employed within defined strata (i.e., Agro-Ecological Zones (AEZ’s) for the US and Africa and a buffer zone approach around the cropland areas of Australia. Continent-specific sample analysis was performed to ensure that an appropriate reference data set was used to generate a valid error matrix indicative of the actual cropland proportion. Each accuracy assessment was performed within the homogenous regions (i.e., strata) of different continents using different sources of reference data to produce rigorous and valid accuracy results. The results indicate that continent-specific modified assessments performed for the three selected continents demonstrate that the accuracy assessment can be easily accomplished for a large area such as the US that has extensive availability of reference data while more modifications were needed in the sampling design for other continents that had little to no reference data and other constraints. Each continent provided its own unique challenges and opportunities. Therefore, this paper describes a tale of these three continents providing recommendations to adapt accuracy assessment strategies and methodologies for validating global cropland extent maps.

Description: Sensors, Vol. 18, Pages 90: Energy-Efficient Region Shift Scheme to Support Mobile Sink Group in Wireless Sensor Networks Sensors doi: 10.3390/s18010090 Authors: Yongbin Yim Kyong Kim Monther Aldwairi Ki-Il Kim Mobile sink groups play crucial roles to perform their own missions in many wireless sensor network (WSN) applications. In order to support mobility of such sink groups, it is important to design a mechanism for effective discovery of the group in motion. However, earlier studies obtain group region information by periodic query. For that reason, the mechanism leads to significant signaling overhead due to frequent flooding for the query regardless of the group movement. Furthermore, the mechanism worsens the problem by the flooding in the whole expected area. To deal with this problem, we propose a novel mobile sink group support scheme with low communication cost, called Region-Shift-based Mobile Geocasting Protocol (RSMGP). In this study, we utilize the group mobility feature for which members of a group have joint motion patterns. Thus, we could trace group movement by shifting the region as much as partial members move out of the previous region. Furthermore, the region acquisition is only performed at the moment by just deviated members without collaboration of all members. Experimental results validate the improved signaling overhead of our study compared to the previous studies.

Description: Sensors, Vol. 18, Pages 89: 3D Indoor Positioning of UAVs with Spread Spectrum Ultrasound and Time-of-Flight Cameras Sensors doi: 10.3390/s18010089 Authors: José Paredes Fernando Álvarez Teodoro Aguilera José Villadangos This work proposes the use of a hybrid acoustic and optical indoor positioning system for the accurate 3D positioning of Unmanned Aerial Vehicles (UAVs). The acoustic module of this system is based on a Time-Code Division Multiple Access (T-CDMA) scheme, where the sequential emission of five spread spectrum ultrasonic codes is performed to compute the horizontal vehicle position following a 2D multilateration procedure. The optical module is based on a Time-Of-Flight (TOF) camera that provides an initial estimation for the vehicle height. A recursive algorithm programmed on an external computer is then proposed to refine the estimated position. Experimental results show that the proposed system can increase the accuracy of a solely acoustic system by 70–80% in terms of positioning mean square error.

Description: Sensors, Vol. 18, Pages 87: A Novel Segment-Based Approach for Improving Classification Performance of Transport Mode Detection Sensors doi: 10.3390/s18010087 Authors: M. Guvensan Burak Dusun Baris Can H. Turkmen Transportation planning and solutions have an enormous impact on city life. To minimize the transport duration, urban planners should understand and elaborate the mobility of a city. Thus, researchers look toward monitoring people’s daily activities including transportation types and duration by taking advantage of individual’s smartphones. This paper introduces a novel segment-based transport mode detection architecture in order to improve the results of traditional classification algorithms in the literature. The proposed post-processing algorithm, namely the Healing algorithm, aims to correct the misclassification results of machine learning-based solutions. Our real-life test results show that the Healing algorithm could achieve up to 40% improvement of the classification results. As a result, the implemented mobile application could predict eight classes including stationary, walking, car, bus, tram, train, metro and ferry with a success rate of 95% thanks to the proposed multi-tier architecture and Healing algorithm.