ALBERT

Description: An image identification method was developed with the aid of a deep convolutional neural network (CNN) and applied to the analysis of inorganic particles using electron holography. Despite significant variation in the shapes of α-Fe2O3 particles that were observed by transmission electron microscopy, this CNN-based method could be used to identify isolated, spindle-shaped particles that were distinct from other particles that had undergone pairing and/or agglomeration. The averaging of images of these isolated particles provided a significant improvement in the phase analysis precision of the electron holography observations. This method is expected to be helpful in the analysis of weak electromagnetic fields generated by nanoparticles showing only small phase shifts.

Description: The skylight on the roof of an atrium can be popular for commercial malls to illuminate the core area of the building. However, the solar radiation and its heat can get into the building together with the daylight, causing excessive cooling load. This paper studies the daylighting and energy performances of skylight coverage area for the air-conditioned atriums in the hot and humid regions. The energy performance with different atrium heights, glass types and the coverage ratios of the skylight are studied. The daylight performance was simulated by the ray-tracing Radiance and was transferred into EnergyPlus for energy evaluations. The finding suggested that, for hot and humid climates, the skylight coverage ratio should be controlled carefully to prevent the excessive solar heat gain. When the on/off lighting control is applied, the total energy consumption of the single-floor cases (or of the top floor for the multi-floor cases) leveled off when the coverage ratio of the skylight reached 9%. Thus, the skylight is favorable to the energy saving of the low-rise or single-floor commercial buildings only under the current assumptions, as the ground of the atrium cannot be well illuminated while the excessive solar radiation gets into the building. The skylight should be shaded in cooling seasons to prevent the excessive solar heat gains.

Description: The production of liquefied natural gas (LNG) is a high energy-consuming process. The study of ways to reduce energy consumption and consequently to reduce operational costs is imperative. Toward this purpose, this study proposes a hybrid system adopting a mixed refrigerant for the liquefaction of natural gas that is precooled with an ammonia/water absorption refrigeration (AR) cycle utilizing the exhaust heat of a molten carbonate fuel cell, 700°C and 2.74 bar, coupled with a gas turbine and a bottoming Brayton super-critical carbon dioxide cycle. The inauguration of the ammonia/water AR cycle to the LNG process increases the cooling load of the cycle by 10%, providing a 28.3-MW cooling load duty while having a 0.45 coefficient of performance. Employing the hybrid system reduces energy consumption, attaining 85% overall thermal efficiency, 53% electrical efficiency and 35% fuel cell efficiency. The hybrid system produces 6300 kg.mol.h−1 of LNG and 146.55 MW of electrical power. Thereafter, exergy and sensitivity analyses are implemented and, accordingly, the fuel cell had an 83% share of the exergy destruction and the whole system obtained a 95% exergy efficiency.

Description: According to the regulation of European Union laws in 2014, it was inevitable to switch to low global warming potential (GWP) fluids in the refrigeration systems where the R404A working fluid is currently used. The GWP of R404A is very high, and the potential for ozone depletion is zero. In this study, energetic and exergetic performance assessment of a theoretical refrigeration system was carried out for R404 refrigerant and its alternatives, comparatively. The analyses were made for R448A, R449A, R452A and R404A. The results of the analysis were presented separately in the tables and graphs. According to the results, the cooling system working with R448A exhibited the best performance with a coefficient of performance (COP) value of 2.467 within the alternatives of R404A followed by R449A and R452A, where the COP values were calculated as 2.419 and 2.313, respectively. In addition, the exergy efficiencies of the system were calculated as 20.62%, 20.22% and 19.33% for R448A, R449A and R452A, respectively. For the base calculations made for R404A, the COP of the system was estimated as 2.477, where the exergy efficiency was 20.71%. Under the same operating conditions, the total exergy destruction rates for R404A, R448A, R449A and R452A working fluids were found to be 3.201 kW, 3.217 kW, 3.298 kW and 3.488 kW, respectively. Furthermore, parametric analyses were carried out in order to investigate the effects of different system parameters such as evaporator and condenser temperature.

Description: Due to the lack of suitable evaluation systems for heating, ventilation, air-conditioning (HVAC) systems with ground source heat pump (GSHP) and energy storage (ES) technologies, it is difficult to design a building HVAC system to achieve optimized design with regard to investment cost, energy saving and environmental protection. This is a study on developing a fuzzy evaluation system by including GSHP and ES with comprehensively determined weights into an HVAC system. A questionnaire method was used and the answers from 21 HVAC experts were analyzed to facilitate the modeling. Taking a commercial integrated project in Nanjing as an engineering case, the evaluation system was tested. If the system with a comprehensive merit value of 0.303 is adopted, the annual operating cost is reduced by 32.5%, the annual total life cycle cost is reduced by 26.5% and the primary energy consumption and carbon emissions are reduced by 10.5%, with the initial investment increased by 6.5%. This study revealed that the newly developed evaluation system is very useful for realizing the optimal design of HVAC systems.

Description: In transmission electron microscope (TEM), both the amplitude and phase of electron beam change when electrons traverse a specimen. The amplitude is easily obtained by the square root of the intensity of a TEM image, while the phase affects defocused images. In order to obtain the phase map and verify the theoretical model of the interaction between electron beam and specimen, a lot of simulations have been performed by researchers. In this work, we have simulated defocus images of a SiC nanowire in TEM with the method of electron optics. Mean inner potential and charge distribution on the nanowire have been considered in the simulation. Besides, due to electron scattering coherence loss of the electron beam has been introduced. A dynamic process with Bayesian optimization was used in the simulation. With the infocus image as input and by adjusting fitting parameters the defocus image is determined with a reasonable charge distribution. The calculated defocus images are in a good agreement with the experimental ones. Here, we present a complete solution and verification method for solving nanoscale charge distribution in TEM.

Description: Among non-toxic and inflammable working fluids, carbon dioxide (CO2) proving a possible choice of refrigerant is gaining full status because of its reducing capacity of global warming and ozone depletion. Heat pump (HP) equipment uses energy more rationally to heat water by reducing emissions and global warming caused by conventional refrigerants. HP capability demands an environmentally friendly refrigerant for their full utilization and high energy saving as well to attaining higher coefficient of performance (COP) without much design corrections. CO2 is checked for sustainability to eliminate the standardized refrigerants such as chlorofluorocarbons (CFC) and hydro-CFC. In this work, the performance of CO2 as an alternate refrigerant in HP for heating water at different pressure, flow rates, evaporator fan speed and preheating have been investigated. HP is accommodated with two condensers. The results showed that the increased mass flow rate had increased COP, overall heat transfer (HT) coefficient (U) and HT. However, logarithmic mean temperature difference was decreased for increasing evaporator’s fan speed and pressure. The outlet water temperature (TWO) of second condenser increased with decreasing water flow rate. Improved COP, HT and TWO of HP are observed from the experimental evaluation in case of preheating of water.

Description: By using power electronic devices, photovoltaic grid-connected power generation may inject harmonics into the power system. As the photovoltaic grid-connected inverter has the same basic structure as the active power filter, so the unified control of the photovoltaic grid and active filtering can be achieved. When the current unified control system compensates harmonics of the grid side, it mainly uses ip-iq harmonic detection method, which is based on instantaneous reactive power theory. When the three-phase voltage is unbalanced, the method has a large voltage phase angle detection error and the signal of the low-pass filter tracking system is long, detection time delay and even failure occur. This paper proposes an improved fast harmonic detection method. When phase deviation or amplitude change occurs to the three-phase voltage, the positive and negative-sequence voltages are simultaneously park transformed. The negative-sequence component is filtered by the current average module to obtain the fundamental amount of the voltage, then the phase angle of the positive-sequence voltage is accurately calculated to improve the harmonic current detection accuracy. Through the study of the integral method, it is found that the least common multiple of each harmonic period can be used as the integral interval, and the integral value is also zero, so the detection delay time is reduced by replacing the low-pass filter with an integration module. The simulation results show that the proposed harmonic detection algorithm can accurately detect harmonics when the three-phase voltage is unbalanced, and about 0.057 s improve the harmonic detection speed compared with the commonly used ip-iq method.

Description: Lithium-ion batteries retired from electric vehicles can provide considerable economic benefits when they are retired for secondary use. However, retired batteries after screening and restructuring still face the problem of inaccurate battery pack state-of-charge (SOC) estimation due to the existence of extreme inconsistency. To solve this problem, an adaptive fading unscented Kalman filtering (AFUKF) algorithm based on the cell difference model (CDM) is proposed in this paper for improving the accuracy of SOC estimation of retired lithium-ion battery packs. Firstly, an improved CDM based on a hypothetical Rint model is developed based on a second-order resistor/capacitor equivalent circuit model. Secondly, an AFUKF algorithm is developed to improve the adaptability and robustness of local state estimation against process modelling errors. Finally, characteristic data are obtained by conducting discharge tests on the screened retired lithium-ion batteries under specific operating conditions. The proposed method can improve the accuracy of SOC estimation of retired lithium-ion battery packs and provide a new idea for SOC estimation of retired lithium-ion battery packs, as shown by the simulated real experimental data.

Description: This is the first report on analyzing the chemical state of Li-ion battery electrodes at different states of charge by using a wavelength-dispersive spectrometer, which has a two-order improved energy resolution in the soft X-ray energy region compared with that of a conventional energy-dispersive X-ray analyzer. Electrodes containing LiMn1.5Ni0.5O4 were charged to prepare Li0.5Mn1.5Ni0.5O4 and λ-Mn0.75Ni0.25O2. The soft X-ray emission spectra obtained from those materials show that the O-K emission signal was drastically decreased throughout the charging process. This suggests that O-2p electron contributed to the electrochemical oxidation. The density of states and Bader charge evaluated from ab initio calculation support this result.

Description: Accurate prediction of electricity sale has a positive effect on power companies in rationally arranging power supply plans, scientifically optimizing power resource allocation, improving power management efficiency, saving energy and reducing consumption. Predicting future electricity sale based on historical electricity sale data can essentially be summarized as a time series forecasting problem. This paper proposes a fast and memory-efficient method, which adopts the expressive power of deep neural networks and the time characteristics of sequence-to-sequence structure (parallel convolution and recurrent neural network) for long range forecasting in electricity sale. Through a large number of experiments and evaluation of real-world datasets, the effectiveness of the proposed method is proved and verified in terms of prediction accuracy, time consuming and training speed.

Description: Operando observation using spin-polarized scanning electron microscopy (spin SEM) has been demonstrated by detecting changes in the magnetization in the writing head of a hard disk drive (HDD) during operation. A current-applying system developed for use in the sample stage of a spin SEM enables imaging of the magnetization changes in the writing head of an HDD while the writing head is activated. Focused ion beam (FIB) technology is used to fabricate electric contacts between the head terminals and the sample holder electrodes. Tungsten film is deposited by FIB technology on the insulator around the writing head to prevent electrostatic charge buildup in the insulators during SEM measurement. This system is well suited for studying the characteristics of writing heads in HDDs in an activated state.

Description: Phase diagram of Au–Si binary alloy system shows a large drop in melting temperature of about 1000K compared with that of Si at a composition of Au:Si = 81:19, where the melting temperature is about 636K. Mixing of Au and Si below the melting temperature was observed by transmission electron microscopy experiment, and it was found that the mixed region shows a diffraction pattern of a diffuse ring intensity indicating an amorphous structure of the mixed area. Si L-emission spectra, which reflect the energy state of bonding electrons of Si atom, of molten Au81Si19 alloy were measured for the first time to investigate the energy state of valence electrons of Si. The Si L-emission spectrum showed a characteristic loss of L1 peak, which is related to sp3 directional bonding in crystalline Si. The intensity profile is also different from that of molten Si reported. This suggests a characteristic atomic arrangement that exists in the molten state. The intensity profile also indicated a small density of state in the molten state at Fermi energy. The obtained spectrum was compared with the calculated density of state of possible crystal structures reported. The comparison suggested that Si atoms are surrounded by eight Au atoms in the molten state of Au81Si19 alloy. The formation of this local atomic arrangement can be an origin of a large drop of melting temperature at about Au:Si = 81:19.

Description: Nowadays, the global energy and environmental problems are becoming more and more serious, which promotes the development and utilization of renewable and clean energy in various countries. Intelligent car involves many subjects such as electronic technology, artificial intelligence, automatic control technology, sensor technology and computer technology and has become an important part of the application of artificial intelligence. Solar cell is a necessary part of the normal operation of the solar intelligent car, which can provide clean energy for the intelligent car. In this paper, the image recognition technology is used to design the intelligent vehicle control system. According to the intelligent vehicle path recognition, the scale invariant feature transform (SIFT) algorithm is improved to improve the accuracy of intelligent vehicle recognition. Data fusion is used to process the data detected by multi-sensor, and the running state of intelligent vehicle is studied. An evaluation method of intelligent vehicle navigation parameters based on association rules and belief network is proposed. The maximum power point tracking control is realized by using the interference observation method to ensure that the intelligent vehicle can track the maximum power point of the solar cell.

Description: The microstructure, chemical composition and mechanical strength of heterogeneous materials of mantis shrimp (Oratosquilla oratoria) saddle were studied. As the key component of the striking system, the saddle comprised two distinct layers including outer layer and inner layer. The outer layer contained blocky microtubules and exhibited compact appearance. The inner layer presented a typical periodic lamellar structure. Due to the change of the thickness of the mineralized outer layer, the organic multilamellar structure became the foundation and enhanced the connection strength (4.55 MPa) at the connect regions between the saddle and merus exoskeleton and membrane, respectively. In the process of fracture, the lamellar structure dispersed the stress effectively by the change of the crack deflection direction and the microfibrils ordered arrangement. The exploration of mantis shrimp saddle region is beneficial to understand the striking system and provided the possibility for the stable connection of heterogeneous materials in engineering fields. The microstructure, heterogeneous material connection characteristics and high mechanical strength of saddle provide bionic models for the preparation of fiber-reinforced resin composites and soft composites.

Description: Correlative light and electron microscopy (CLEM) is an excellent approach for examining the cellular localization of biomolecules. Here, we developed a simple method for CLEM by combining pre-embedding immunohistochemistry with a novel fluorescent probe, namely Fluolid NS Orange, and an embedding resin called ʻDurcupan™ʼ. Specimens were embedded in Durcupan™ or LR White after immunolabeling and post-fixation using glutaraldehyde and osmium tetroxide. Next, ultrathin sections were prepared on a finder grid with navigation markers. The section of the specimen embedded in Durcupan™ was found to be more stable against electron beam irradiation than specimens embedded in LR White. A fluorescence light microscopy image and a transmission electron microscopy (TEM) image, at wide-field, and low magnification, were independently obtained with the same ultrathin section. Using the three corners between finder grid bars as landmarks, fluorescence light microscopy images were superimposed with wide-field, low-magnification TEM images to identify the region of interest, which was subsequently enlarged to ascertain cellular structures localized beneath fluorescent signals. However, the enlarged TEM images appeared blurred, and fluorescence signals had a hazy appearance. To resolve this, the enlarged TEM images were replaced by high-resolution TEM images focused directly on the region of interest, thereby facilitating the collection of high-resolution CLEM images. The simple sample processing method for CLEM using osmium-resistant Fluolid NS Orange and electron beam damage-resistant Durcupan™ allowed the determination of the precise localization of fluorescence signals at subcellular levels.

Description: Degradation of the crystalline quality of transmission electron microscopy specimens in silicon prepared with different conditions has been examined using convergent-beam electron diffraction (CBED). The specimens are prepared using focused ion beam (FIB) with different accelerating voltages, Ar-ion milling and crushing method. Symmetry breaking of CBED patterns was quantitatively evaluated by symmetry breaking index S, which has been previously reported. The degradation and inhomogeneity of the FIB specimen were suppressed by decreasing the accelerating voltages of the FIB fabrication in the final process.

Description: Reversibly photoswitchable fluorescent proteins (RSFPs) are a class of fluorescent proteins whose fluorescence can be turned on and off by light irradiation. RSFPs have become essential tools for super-resolution (SR) imaging. Because most SR imaging techniques require high-power-density illumination, mitigating phototoxicity in cells due to intense light irradiation has been a challenge. Although we previously developed an RSFP named Kohinoor to achieve SR imaging with low phototoxicity, the photoproperties were insufficient to move a step further to explore the cellular dynamics by SR imaging. Here, we show an improved version of RSFP, Kohinoor2.0, which is suitable for SR imaging of cellular processes. Kohinoor2.0 shows a 2.6-fold higher fluorescence intensity, 2.5-fold faster chromophore maturation and 1.5-fold faster off-switching than Kohinoor. The analysis of the pH dependence of the visible absorption band revealed that Kohinoor2.0 and Kohinoor were in equilibria among multiple fluorescently bright and dark states, with the mutations introduced into Kohinoor2.0 bringing about a higher stabilization of the fluorescently bright states compared to Kohinoor. Using Kohinoor2.0 with our SR imaging technique, super-resolution polarization demodulation/on-state polarization angle narrowing, we conducted 4-h time-lapse SR imaging of an actin filament network in mammalian cells with a total acquisition time of 480 s without a noticeable indication of phototoxicity. Furthermore, we demonstrated the SR imaging of mitochondria dynamics at a time resolution of 0.5 s, in which the fusion and fission processes were clearly visualized. Thus, Kohinoor2.0 is shown to be an invaluable RSFP for the SR imaging of cellular dynamics.

Description: The spatiotemporal organization of chromatin is regulated at different levels in the nucleus. Epigenetic modifications such as DNA methylation and histone modifications are involved in chromatin regulation and play fundamental roles in genome function. While the one-dimensional epigenomic landscape in many cell types has been revealed by chromatin immunoprecipitation and sequencing, the dynamic changes of chromatin modifications and their relevance to chromatin organization and genome function remain elusive. Live-cell probes to visualize chromatin and its modifications have become powerful tools to monitor dynamic chromatin regulation. Bulk chromatin can be visualized by both small fluorescent dyes and fluorescent proteins, and specific endogenous genomic loci have been detected by adapting genome-editing tools. To track chromatin modifications in living cells, various types of probes have been developed. Protein domains that bind weakly to specific modifications, such as chromodomains for histone methylation, can be repeated to create a tighter binding probe that can then be tagged with a fluorescent protein. It has also been demonstrated that antigen-binding fragments and single-chain variable fragments from modification-specific antibodies can serve as binding probes without disturbing cell division, development and differentiation. These modification-binding modules are used in modification sensors based on fluorescence/Förster resonance energy transfer to measure the intramolecular conformational changes triggered by modifications. Other probes can be created using a bivalent binding system, such as fluorescence complementation or luciferase chemiluminescence. Live-cell chromatin modification imaging using these probes will address dynamic chromatin regulation and will be useful for assaying and screening effective epigenome drugs in cells and organisms.

Description: Alveolar bone repair after tooth extraction is essential after oral surgeries. Various grafting materials are used to promote the regeneration of lost alveolar bone. This study analysed the morphological features of the tissue regeneration process using deproteinized bovine bone mineral (DBBM). DBBM was used to densely fill the extraction sockets in beagle dogs. Following resin casting of the vasculature, stereomicroscopy and scanning electron microscopy were used to observe blood vessels and hard tissues in haematoxylin and eosin-stained sections on postoperative days 14, 30 and 90 in conjunction with vascular endothelial growth factor (VEGF) immunostaining to evaluate alveolar bone vascularization. On day 14 post-operation, the DBBM granules tightly filled the extraction sockets, maintained alveolar margin height and formed a scaffold for aiding angiogenesis and new bone formation. On day 30, new bone formation was observed around the DBBM granules. By day 90, bone tissue regeneration progressed in both groups but was more pronounced in the DBBM group. Alveolar margin height was maintained in the DBBM group throughout the study. Furthermore, VEGF expression in the DBBM group was detected around newly formed bone. We conclude that DBBM acts as a suitable scaffold for new bone generation, as well as angiogenesis around healing alveolar bone, and that it has the potential to play a key role in vascularization and bone formation.

Description: This paper presents a quick and straightforward method to evaluate image distortion in scanning electron microscopy using a certified reference material (CRM) as a test specimen. The CRM has a square dot-array structure, whose dot-pitch has an accredited value. By calculating the distance between each dot of the CRM via image analysis, we can detect the distortion in the image as variations of dot interval. Furthermore, by considering the uncertainty of the certified value, it is possible to quantitatively evaluate the significance of the distortion in the image. This method enables us to easily estimate the uncertainty from image distortion, which can improve the reliability of measurement by scanning electron microscopy.

Description: High resolution study of the giant viruses presents one of the latest challenges in cryo-electron microscopy of viruses. Too small for light microscopy, but too large for easy study at high resolution by electron microscopy, they range in size from ~0.2-2 μm, from high symmetry icosahedral viruses such as Paramecium burseria Chlorella virus 1 to asymmetric forms like Tupanvirus or Pithovirus. To attain high resolution, two strategies exist to study these large viruses by cryo-EM: firstly, increasing the acceleration voltage of the electron microscope to improve sample penetration and overcome the limitations imposed by electro-optical physics at lower voltages, and secondly the method of “block-based reconstruction” pioneered by Michael G. Rossmann and his collaborators, which resolves the latter limitation through an elegant leveraging of high symmetry, but cannot overcome sample penetration limitations. In addition, more recent advances in both computational capacity and image processing also yield assistance in studying the giant viruses. Especially, the inclusion of Ewald sphere correction can provide large improvements in attainable resolutions for 300 kV electron microscopes. Despite this, the study of giant viruses remains a significant challenge.

Description: Accompanied with the clinical routine examination demand increase sharply, the efficiency and accuracy are the first priority. However, automatic classification and localization of cells in microscopic images in super depth of Field (SDoF) system remains great challenges. In this paper, we advance an object detection algorithm for cells in the SDoF micrograph based on Retinanet model. Compared with the current mainstream algorithm, the mean average precision (mAP) index is significantly improved. In the experiment of leucorrhea samples and fecal samples, mAP indexes are 83.1% and 88.1%, respectively, with an average increase of 10%. The object detection model proposed in this paper can be applied to feces and leucorrhea detection equipment, and significantly improve the detection efficiency and accuracy.

Description: To reveal the flame propagation and CO/CO2 generation characteristics of coal dust explosion, lignite dust cloud is studied through experiment and numerical simulation in a horizontal pipeline apparatus. The result indicated that within 0.5 s after explosion, the flame propagation distance rapidly increases until the explosion reaction is sufficient. FLUENT is used to simulate the flame propagation and CO/CO2 generation characteristics. It is found that the simulation error is acceptable and the simulation result is consistent with the experimental result. The explosion space is divided into five zones by simulating the flame temperature. It also revealed that z = 0.3 ~ 0.6 m in the pipeline generates more CO because it is closed to the ignition zone. As the explosion spreads through the pipeline, the generated CO accumulates to the bottom of the pipeline, and the generated CO2 accumulates more in the upper part of the pipeline.

Description: In city gas pressure reducing stations, in order not to hydrate natural gas after a sudden drop in pressure, the gas temperature is raised by a heater. The increase in temperature is such that after the pressure drop, the gas inside the pipes does not freeze. These heaters are gas burning and very high consumption, and because they use fossil fuels, produce environmental pollution. Accordingly, in this research, solar energy will be used to preheat the gas, which will be used for the most accurate analysis of TRNSYS software. In this regard, the amount of utilization of the sun and the amount of energy required for preheating will be obtained. After the implementation of the TRNSYS program, the highest amount of energy supply by the sun is related to spring, which on this day provides 55% of the thermal energy required by the load by solar energy.

Description: Amnion membrane studies related to miscarriage have been conducted in the field of obstetrics and gynecology. However, the distribution of stem cells within the amnion and the differences in the properties of each type of stem cells are still not well understood. We address this gap in knowledge in the present study where we morphologically classified the amnion membrane, and we clarified the distribution of stem cells here to identify functionally different amniotic membrane–derived stem cells. The amnion can be divided into a site that is continuous with the umbilical cord (region A), a site that adheres to the placenta (region B), and a site that is located opposite the placenta (region C). We found that human amnion epithelial stem cells (HAECs) that strongly express stem cell markers were abundant in area A. HAEC not only expressesed stem cell-specific surface markers TRA-1-60, Tra-1-81, SSEA4, SSEA3, but was also OCT-3/4 positive and had alkaline phosphatase activity. Human amniotic mesenchymal stem cells expressed KLF-A, OCTA, Oct3/4, c-MYC and Sox2 which is transcription factor. Especially, in regions A and B they have expressed CD73, and the higher expression of BCRP which is drug excretion transporter protein than the other parts. These data suggest that different types of stem cells may have existed in different area. The understanding the relation with characteristics of the stem cells in each area and function would allow for the efficient harvest of suitable HAE and HAM stem cells as using tool for regenerative medicine.

Description: In order to reduce the carbon emission and improve the de-carbonization in distribution of vehicle routing problem with simultaneous delivery and pickup (VRPSDP), a two-stage disruption management method based on the changes of customer demand is proposed in this paper. Firstly, a mathematics model of VRPSDP is established to optimize the parameters and the distribution carbon emission cost and time window deviation. Next, several carbon emission equations in VRPSDP are inducted and designed. Considering the strong global searching ability of quantum particle swarm optimization (QPSO) and combing the advantages of superposition and parallelism of quantum computing, a multi-phase QPSO (MQPSO) is proposed to enhance global searching ability. At last, on the basis of Solomon examples, the validity of the proposed model and MQPSO is tested and compared with the classical algorithms at present. The simulation results show that the proposed method can not only achieve the goal of performance but also meet the practical requirements of reducing carbon emissions in VRPSDP.

Description: Renewable energy sources cannot guarantee long-term and stable output supply when they are given energy consumption at the load end. At the same time, traditional solar and utility power supply systems cannot guarantee the priority of using solar energy to generate electricity, which has certain limitations. In this regard, an energy control strategy for achieving smooth and no backflow switching and prioritizing the use of clean energy solar energy under a joint power supply system of a solar power grid and a municipal power grid is proposed, which is used for a conventional combined power supply system of a contactor switching circuit. A topology of low voltage power grid is proposed, which effectively reduces the impact on the solar power grid and the municipal power grid during the system switching process combined control mode for controlling the current phase and repetitive control at the output end of the solar power grid in the combined power supply mode, and adding a feedforward control method for the grid voltage is adopted to ensure that the solar grid and the municipal power prioritize the use of clean energy solar energy and, at the same time, ensure the maximum utilization of solar energy. This paper chose the combined power supply system with the solar power grid and the municipal power grid as the object of this research. The topology structure and controlling strategy of the power supply system were comprehensively and deeply researched, and on this basis, the combined power supply system prototype was designed on the foundation of DSP28335 and CPLD. Moreover, hardware parameters are designed in the system, and an energy management optimization algorithm based on the system is developed on the corresponding experimental platform. The experimental results show that the proposed energy control strategy can effectively reduce the impact on the solar power grid and the municipal power grid during the system switching process, ensure that the solar power grid and the municipal power grid have no backflow combined power supply and give priority to the use of clean energy solar energy.

Description: Stand-alone hybrid energy systems are an enticing option for electrification in remote areas in several aspects such as grid extension difficulty, economic feasibility and reliability. The use of existing micro-hydropower (MHP) with other renewable resources in rural areas has not been well studied. Moreover, it is challenging to use mathematical optimization algorithms for these kinds of real-world problems, so the derivative-free algorithm is highly sought. In this paper, a methodology has been proposed to perform the optimal sizing, financial and generation uncertainty analysis of solar photovoltaic (SPV) based on an MHP that is proposed to handle the intermittent power output of the SPV. The analysis is performed in two cases: using storage and without storage. The optimal sizing is performed using the least present value cost and reliability constraint using different derivative-free algorithms. The storage-based hybrid system has been found to generate reliable electricity at minimal cost than without a storage-based one. This study would be helpful to propose electrification and existing micro-hydro reinforcement policies to provide reliable electricity in rural areas.

Description: A powerful aspect of single particle cryogenic electron microscopy (cryo-EM) is its ability to determine high-resolution structures from samples containing heterogeneous mixtures of the same macromolecule in different conformational or compositional states. Beyond determining structures at higher resolutions, one outstanding question is if macromolecules with only subtle conformation differences, such as the same protein bound with different ligands in the same binding pocket, can be separated reliably, and if information concerning binding kinetics can be derived from the particle distributions of different conformations obtained in classification. In this study, we address these questions by assessing the classification of synthetic heterogeneous datasets of TRPV1 generated by combining different homogeneous experimental datasets. Our results indicate that classification can isolate highly homogeneous subsets of particle for calculating high-resolution structures containing individual ligands, but with limitations.

Description: In the present study, we employ fluorescence spectroscopy, dynamic light scattering, and molecular docking methods. Binding of anticancer drug anastrozole with human lysozyme (HL) is studied. Binding of anastrozole to HL is moderate but spontaneous. There is anastrozole persuaded hydrodynamic change in HL, leading to molecular compaction. Binding of anastrozole to HL also decreased in vitro lytic activity of HL. Molecular docking results suggest the electrostatic interactions and van der Waals forces played key role in binding interaction of anastrozole near the catalytic site. Binding interaction of anastrozole to proteins other than major transport proteins in blood can significantly affect pharmacokinetics of this molecule. Hence, rationalizing drug dosage is important. This study also points to unrelated effects that small molecules bring in the body that are considerable and need thorough investigation.

Description: Background. Young people are challenged with sexual and reproductive health (SRH) problems due to limited access to services and information. It contributes a high burden of sexually transmitted disease, unsafe abortion, and premature mortality, especially in low-income countries like Ethiopia. Hence, this study aimed at assessing the SRH service utilization and associated factors among college students at West Arsi Zone in Oromia region, Ethiopia. Methods. Institutional-based cross-sectional study was conducted among 519 randomly selected college students from January 01, 2019, up to April 30, 2019. Data were collected through self-administered pretested questionnaires. Data entry and analysis for descriptive and logistic regression models were performed by using SPSS (version 23). The result was declared as statistically significant at p 

Description: To meet the different requirements in the industrial area, a novel reconfigurable parallel mechanism is proposed based on the spatial multiloop overconstrained mechanism. The configurations can be changed by driving the low-DOF (degree-of-freedom) overconstrained mechanism. The mobility of this mechanism is investigated. And the kinematic model and Jacobian matrix are both established. Based on the Jacobian matrix, the workspace, stiffness, and conditional number are all analyzed. To focus on the application in the industrial area, this paper proposes a method to establish the relationship between the performance and the structural parameters by using the modified BP neural network. Based on this method, the structural parameters can be chosen by the requirements of the special task in the industrial area. Finally, some numerical examples are presented to verify the method.

Description: In this paper, the multibody parachute-payload system is simplified and analyzed. A six-degree-of-freedom rigid body flight dynamic model is established to calculate the flight trajectory, attitude, velocity, and drop point of the parachute-payload system. Secondly, the random interference factors that may be encountered in the actual airdrop test of the parachute system are analyzed. According to the distribution law of the interference factors, they are introduced into the flight dynamic model. The Monte Carlo method is used to simulate the target and predict the flight trajectory and landing point distribution of the parachute system. The simulation results can provide technical support and theoretical basis for the parachute airdrop test. Finally, the genetic algorithm is used to identify the aerodynamic parameters of the large-scale Disk-Gap-Band parachute. The simulation results are in good agreement with the test results, which shows that the research method proposed in this paper can be applied to study practical engineering problems.

Description: The flavonoids are compounds synthesized by plants, and they have properties such as antioxidant, anticancer, anti-inflammatory, and antibacterial, among others. One of the most important bioactive properties of flavonoids is their antioxidant effect. Synthetic antioxidants have side toxic effects whilst natural antioxidants, such as flavonoids from natural sources, have relatively low toxicity. Therefore, it is important to incorporate flavonoids derived from natural sources in several products such as foods, cosmetics, and drugs. For this reason, there is currently a need to extract flavonoids from plant resources. In this review are described the most important parameters involved in the extraction of flavonoids by unconventional methods such as ultrasound, pressurized liquid extraction, mechanochemical, high hydrostatic pressure, supercritical fluid, negative pressure cavitation, intensification of vaporization by decompression to the vacuum, microwave, infrared, pulsed electric field, high-voltage electrical discharges, and enzyme-assisted extraction. There are no unified operation conditions to achieve high yields and purity. Notwithstanding, progress has been achieved in the development of more advanced and environmentally friendly methods of extraction. Although in literature are found important advances, a complete understanding of the extraction process in each of the unconventional techniques is needed to determine the thermodynamic and kinetic mechanisms that govern each of the techniques.

Description: This paper proposes high-accuracy and reliable attitude measurement methods exclusive for CubeSat with restrictions of low cost, limited space, and low power consumption. The attitude measurement unit is equipped with Commercial Off-The-Shelf (COTS) components including Micro-Electro-Mechanical System (MEMS) gyro and two simultaneously operating star trackers (STR) to enhance the measurement accuracy. The Multiplicative Extended Kalman Filter (MEKF) is used to estimate the attitude of CubeSat, and four kinds of attitude estimation layouts are put forward according to the idea of weighted average of two quaternions from two STR and different architectures of information fusion. Using the proposed methods, the attitude measurement unit can continuously provide accurate and reliable attitude knowledge for attitude control unit when the CubeSat is running in orbit. Numerical simulation is performed to verify the effectiveness of the proposed methods, and it offers a reference for CubeSat developers from the perspective of engineering application.

Description: Clearances in the joints of real mechanisms are unavoidable due to assemblage, manufacturing errors, and wear. The dual-axis driving and positioning mechanism is one kind of space actuating mechanism for satellite antenna to implement precise guidance and positioning. However, in dynamics analysis and control of the satellite antenna system, it is usually assumed that the revolute joint in the satellite antenna system is perfect without clearances or imperfect with planar radial clearance. However, the axial clearance in an imperfect revolute joint is always ignored. In this work, the revolute joint is considered as a 3D spatial clearance joint with both the radial and axial clearances. A methodology for modeling the 3D revolute joint with clearances and its application in satellite antenna system is presented. The dynamics modeling and analysis of the satellite antenna system are investigated considering the 3D revolute clearance joint. Firstly, the mathematical model of the 3D revolute clearance joint is established, and the definitions of the radial and axial clearance are presented. Then, the potential contact modes, contact conditions, and contact detection of the 3D revolute clearance joint are analyzed. Further, the normal and tangential contact force models are established to describe the contact phenomenon and determine the contact forces in the 3D revolute clearance joint. Finally, a satellite antenna system considering the 3D revolute clearance joint with spatial motion is presented as the application example. Different case studies are presented to discuss the effects of the 3D revolute clearance joint. The results indicate that the 3D revolute clearance joint will lead to more severe effects on the dynamic characteristics of the satellite antenna system. Therefore, the effects of axial clearance on the satellite antenna system cannot be ignored in dynamics analysis and design of the satellite antenna system.

Description: As Unmanned Aerial Vehicles (UAVs) are widely used in many applications, a lot of military missions in confrontational environments are being undertaken by UAV swarm rather than human beings due to its advantages. In confrontational environments, the reliability and availability of UAV swarm would be the major concern because of UAVs’ vulnerability, so damage-tolerant task assigning algorithms are of great importance. In this paper, we come up with a novel damage-tolerant framework for assigning real-time tasks to UAVs with dynamical states in confrontational environments. Different from existing scheduling methods, we not only assign tasks but also back up copies of tasks to UAVs when needed, to promote reliability. Meanwhile, we adopt an overlapping mechanism, including Backup-Primary overlapping and Backup-Backup overlapping, in assignment to save the limited swarm resources. On the basis of the damage-tolerant and overlapping mechanism, for the first time, we propose a new damage-tolerant task assignment algorithm named DTTA, aiming at promoting the task success probability. Extensive experiments are conducted based on random synthetic workloads to compare DTTA with three baseline algorithms. The experimental results indicate that DTTA can efficiently promote the probability of tasks’ success without affecting the effectiveness of swarms in confrontational environments.

Description: Background. The rational use of drugs requires that patients receive medications appropriate to their clinical needs, in doses that meet their own individual requirements, for an adequate period of time, and at the lowest cost to them and their community with full information and with the lowest possible cost. If one of these is not met, it is referred to as irrational drug use. Many drugs have been sold or prescribed inappropriately in the world, and a significant part of the world population lacks access to essential medicine. The aim of this study was to assess practice towards rational drug use at Finoteselam and Asirade Zewudie hospitals. Methods. A cross-sectional study design was used for this study, and the study was conducted from October 11 to November 30, 2019. A total of 770 prescriptions were selected as per WHO criteria by using systematic random sampling and reviewed with the help of an observational checklist. The data were entered and processed with SPSS version 25 and evaluated using the WHO criteria. Result. The average number of drugs per prescription was 1.8 and 2.05, antibiotics encountered were 77.7% and 72.5%, injections encountered were 5.97% and 7.01%, percentage of drugs prescribed by generic names was 97% and 93.4%, counseling time was 1.6 minutes and 2.25 minutes, and dispensing time was 51.3 seconds and 62.72 seconds at Finoteselam and Asirade Zewudie hospitals, respectively. Conclusion. The majority of WHO core drug use indicators were not met in the two hospitals. The average number of drugs encountered in Asirade Zewudie hospital was slightly higher than the WHO recommended range, whereas the average number of drugs encountered in Finoteselam hospital was exactly equal. The percentage of antibiotics encountered was very high compared with WHO recommendation, but the percentage of injections encountered was below the WHO recommended range and time spent on counseling and dispensing was too short when compared with WHO recommendation. In addition to this, both hospitals had no essential drug list or formulary as well as a key drug list.

Description: Rice husk biochars were prepared by carbonization at 400–600°C. The products were analyzed by FTIR, SEM-EDS, BET, and approximate analysis in order to find final products with the best properties and the lowest carbonization temperature. It has been found that the biochar prepared at 500°C, which has 37.86 ± 0.11% yield, 341.0776 m2/g of BET surface area, and 0.136639 cm3/g of micropore volume, is suitable for use as a root supplement in the aquaponic system. The aquaponic systems consist of aquaculture and a hydroponic system with and without biochar supplement. The control experiment consists of an aquaculture and planting panel with biochar supplement disconnected from each other. Tilapia and Chinese morning glory were used for growth studies. The water quality from all aquaculture ponds has also been analyzed at an interval of 10 days for 47 days. The results showed that the growth rates of Tilapia and Chinese morning glory in the aquaponic system with biochar were clearly higher than in the control experiment, which is in accordance with the water quality in each aquaculture pond. However, the growth rates of Tilapia (23.5 g/body vs. 22.7 g/body) and morning glory (3.907 g/stem vs. 2.609 g/stem) in supplemented biochar system tend to be higher than the nonsupplemented biochar system. It has been shown that rice husk biochar can help in treating water in the aquaponic system by increasing the amount of dissolved oxygen in the aquaculture water and conversion of toxic compounds to those beneficial for plant growth.

Description: Despite the achievements reported from using rainwater harvesting systems, the contribution and drawbacks that affect their usage in mountainous landscapes have received little attention. The uptake and usage of domestic rooftop rainwater harvesting systems (RRWHS) in developing countries is on the increase due to increasing water scarcities. We explored the effect of rainfall variability on water supply and the downsides of using the systems by rural households in Uganda. The objectives were to assess the variability of rainfall (1985–2018), categorise RRWHS used, and examine the influence of slope ranges on the placement of systems and also to quantify the harvested and saved rainwater and establish the factors that affected system usage. Rainfall variability was assessed using a Mann–Kendall test, while system contributions and drawbacks were examined using socioeconomic data. A representative of 444 households were selected using a multicluster sampling procedure and interviewed using semistructured questionnaires. Findings revealed that the months of March, April, September, August, and October experienced an upward trend of rainfall with a monthly coefficient of variation between 41 and 126%. With this, households responded by employing fixed (reinforced concrete tanks, corrugated iron tanks, and plastic tanks) and mobile RRWHS (saucepans, metallic drums/plastic drums, jerrycans, and clay pots). At the high altitude, households deployed mostly plastic jerrycans and industrial plastic/metallic drums to harvest and save water. Overall, the mean annual volume of rainwater harvested on the slopes of Mt. Elgon was 163,063 m3/yr, while the potential to save water ranged from 4% to 7% of the annual household water demand. The factors that hindered the deployment of RRWHS to harvest and save water were high operational costs, price fluctuations, unreliable rainfall pattern, inadequate funds, and limited accessibility. The rainfall received if well-harvested and saved can redeem households of water insecurity, though there is an urgent need of subsidies from the government to increase accessibility of the systems.

Description: Estimating the 3D pose of the space object from a single image is an important but challenging work. Most of the existing methods estimate the 3D pose of known space objects and assume that the detailed geometry of a specific object is known. These methods are not available for unknown objects without the known geometry of the object. In contrast to previous works, this paper devotes to estimate the 3D pose of the unknown space object from a single image. Our method estimates not only the pose but also the shape of the unknown object from a single image. In this paper, a hierarchical shape model is proposed to represent the prior structure information of typical space objects. On this basis, the parameters of the pose and shape are estimated simultaneously for unknown space objects. Experimental results demonstrate the effectiveness of our method to estimate the 3D pose and infer the geometry of unknown typical space objects from a single image. Moreover, experimental results show the advantage of our approach over the methods relying on the known geometry of the object.

Description: Odor-baited devices are increasingly needed to compliment long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) for control of residual malaria transmission. However, the odor-baited devices developed so far are bulky, dependent on the source of electricity and carbon dioxide (CO2), and they are logistically unsuitable for scaling up in surveillance and control of malaria vectors. We designed a passive and portable outdoor host seeking device (POHD) and preliminarily evaluated suitable components against Anopheles arabiensis that maintains residual malaria transmission. Experiments were conducted using semifield reared An. arabiensis within the semifield system at Ifakara Health Institute (IHI) in southeastern Tanzania. These mosquitoes were exposed to Suna traps® baited with BG lures or source of light and augmented with carbon dioxide (CO2) in view of identifying best attractants necessary to improve attractiveness of designed POHD. Two Suna traps® were hanged at the corner but outside the experimental hut in a diagonal line and rotated between four corners to control for the effect of position and wind direction on mosquito catches. Furthermore, mosquitoes were also exposed to either a bendiocarb-treated or bendiocarb-untreated POHD baited with Mbita blend, Ifakara blend, and worn socks and augmented with warmth (i.e., 1.5 liter bottle of warm water) inside an experimental hut or a screened rectangular box. This study demonstrated that mosquitoes were more strongly attracted to Suna trap® baited with BG lures and CO2 relative to those traps baited with a source of light and CO2. The POHD baited with synthetic blends attracted and killed greater proportion of An. arabiensis compared with POHD baited with worn socks. Efficacy of the POHD was unaffected by source of warmth, and it was reduced by about 50% when the device was tested inside a screened rectangular box relative to closed experimental hut. Overall, this study demonstrates that the POHD baited with synthetic blends (Mbita and Ifakara blends) and bendiocarb can effectively attract and kill outdoor biting malaria vector species. Such POHD baited with synthetic blends may require the source of CO2 to enhance attractiveness to mosquitoes. Further trials are, therefore, ongoing to evaluate attractiveness of improved design of POHD baited with slow-release formulation of synthetic blends and sustainable source of CO2 to malaria vectors under semifield and natural environments.

Description: Gastric diseases are increasing with the infection of Campylobacter jejuni. Late stages of infection lead to peptic ulcer and gastric carcinoma. C. jejuni infects people within different stages of their life, especially childhood, causing severe diarrhea; it infects around two-thirds of the world population. Due to bacterial resistance against standard antibiotic, a new strategy is needed to impede Campylobacter infections. Plants provide highly varied structures with antimicrobial use which are unlikely to be synthesized in laboratories. A special feature of higher plants is their ability to produce a great number of organic chemicals of high structural diversity, the so-called secondary metabolites. Twenty plants were screened to detect their antibacterial activities. Screening results showed that Rheum officinalis was the most efficient against C. jejuni. Fractionation pattern was obtained by column chromatography, while the purity test was done by thin-layer chromatography (TLC). The chemical composition of bioactive compound was characterized using GC-MS, nuclear magnetic resonance, and infrared analysis. Minimal inhibitory concentration (MIC) of the purified compound was 31.25 µg/ml. Cytotoxicity assay on Vero cells was evaluated to be 497 µg/ml. Furthermore, the purified bioactive compound activated human lymphocytes in vitro. The data presented here show that Rheum officinalis could potentially be used in modern applications aimed at the treatment or prevention of foodborne diseases.

Description: Helicobacter pylori (H. pylori) is the most common cause of gastric ulcer; however, its association with gastric cancer has been proved through a variety of studies. Importantly, H. pylori infection affects around half of the world’s population leading to a variety of gastric problems and is mostly present in asymptomatic form. Although about 20% of people infected with H. pylori develop preneoplastic gastric lesions in later stages of their life, around 2% of infected individuals develop gastric cancer. Nevertheless, the outcome of H. pylori infection is determined by complex interaction between the host genetics, its environment, and virulence factors of infecting strain. There are several biomarkers/traits of H. pylori that have been linked with the onset of cancer. Among these, presence of certain major virulence factors including cytotoxin-associated gene A (CagA), vacuolating cytotoxin (VacA), and outer inflammatory protein A (OipA) plays a significant role in triggering gastric cancer. These factors of H. pylori make it a potent carcinogen. Therefore, eradication of H. pylori infection has shown positive effects on decreasing the risk of gastric cancer, but this has become a challenge due to the development of antibiotic resistance in H. pylori against the antibiotics of choice. Thus, the unmet need is to develop new and effective treatments for H. pylori infection, considering the antimicrobial resistance in different regions of the world. This review discusses the properties of H. pylori associated with increased risk of gastric cancer, antibiotic resistance pattern, and the possible role of eradication of H. pylori in preventing gastric cancer.

Description: Natural products are used as alternative drugs in traditional medicine to treat infection and inflammation and relieve pain. Heartwood of Cassia garettiana Craib has been investigated as an ingredient in Thai traditional medicine for anti-HIV protease, but there is no report on its antibacterial and anti-inflammatory activities. The objectives of this study were to investigate the anti-inflammatory and antibacterial activities, time-kill profile, and main active constituents of an ethanolic extract of C. garettiana heartwood. The study followed the generally accepted experimental design. All tests were investigated in triplicate. The heartwood of C. garettiana was extracted by maceration with 95% EtOH. The antibacterial activity of the extract and its chemical constituents were determined by their MIC values using resazurin as an indicator. Time-kill profile was determined at 0, 2, 4, 6, 8, 10, 12, and 24 hrs and expressed as log CFU/mL. The anti-inflammatory activity of the extract and its chemical components was investigated by their inhibiting effect on IL-6 and TNF-α production by ELISA. The ethanolic extract was analyzed for its chemical constituents by HPLC technique. The ethanolic extract showed both dose- and time-dependent bactericidal effects against Staphylococcus aureus, methicillin-resistance Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, Salmonella Typhi, Salmonella Typhimurium, Klebsiella pneumoniae, and Shigella dysenteriae with MIC values of 312.5, 312.5, 312.5, 1,250, 2,500, 625, 625, 2,500, and 625 μg/mL, respectively. It showed an inhibiting effect on IL-6 production at concentrations of 12.5 to 100 μg/mL. The main active chemical constituent of C. garettiana was piceatannol that showed antibacterial activity against all test bacteria except P. aeruginosa. C. garettiana showed a broad spectrum of antibacterial activity against both Gram-negative and Gram-positive bacteria. Piceatannol and resveratrol from the plant strongly inhibited IL-6 production. Based on these results, we concluded that the ethanolic extract of C. garettiana showed both an antibacterial activity and inhibition of IL-6. Piceatannol is the active constituent of the extract and showed anti-inflammatory and antibacterial activities against Gram-negative and Gram-positive bacteria.

Description: Deep borehole heat exchanger (DBHE) technology does not depend on the existence of hot water reservoir and can be used in various regions. However, the heat extraction from DBHE can hardly be improved due to poor thermal conductivity of rocks. Here, a single-well enhanced geothermal system (SWEGS) is proposed, which has a larger heat-exchange area of artificial reservoir created by fracturing hydrothermal technology. We find that, due to heat convection between rocks and fluid, the extracted thermal output for SWEGS is 4772.73 kW, which is 10.64 times of that of DBHE. By changing the injection water temperature, volume flow rate, and artificial reservoir volume, it is easy to adjust the extracted thermal output to meet the requirement of building thermal loads varying with outdoor air temperature. Understanding these will enable us to better apply SWEGS technology and solve the fog and haze problem easily and efficiently.

Description: A mathematical model based on minimal thermal resistance and equal law of specific equivalent thermal conductivity is developed to discuss the heat transfer characteristics of ablative thermal insulating material from the mesoscopic scale. Based on the statistical results of mesoscopic parameters, the microstructure unit cell model was established to analyze the influence rule of mesoscopic parameterization which includes the size, distribution, and positional relation of microsphere and fiber. The results show that the equivalent thermal conductivity decreases with the density, size, distribution area, and distance of microsphere and the space distance and volume fraction of fiber decreasing. Besides, the equivalent thermal conductivity will become larger when more quality of heat transfers along the fiber direction. Exploring the relationship between the macroscopic heat transfer process and the microstructure is meaningful for exploring the heat transfer behavior of thermal insulating material and improvement of the processing technology.

Description: Extreme rainfall accompanied by strong winds hit the province of Bengkulu in the western coastal area of Sumatera Island during September 19-20, 2017, causing floods and landslides in Seluma and Central Bengkulu district. This extreme rainfall was recorded by Bengkulu Meteorological Station about 257.0 mm day−1 using rain-gauge observation. The spatial distribution of extreme rainfall cannot be seen if only using a rain-gauge observation in this location. The spatial distribution of extreme rainfall is needed to identify the impact of rainfall on landslides in large areas. The study aims to (1) develop the reconstruction of the spatial distribution of extreme rainfall using weather radar and (2) investigate the trigger that caused extreme rainfall by analyzing the synoptic-scale tropical waves. Each weather radar datum is saved in a Constant Altitude Plan Position Indicator (CAPPI). To get rainfall information, the CAPPI must be derived from Quantitative Precipitation Estimation (QPE) values. In this paper, we derived CAPPI using a Marshall-Palmer reflectivity-rain rate relationship. The result shows that rainfall formed on September 20, 2017, 21.00 UTC with total daily rainfall ranged between 176 and 247 mm in both districts and the mean of total daily rainfall has exceeded the average of monthly rainfall. The analysis of tropical waves suggests that only Kelvin waves were active and served as a possible trigger factor while the Madden-Julian Oscillation (MJO) and Equatorial Rossby (ER) waves were inactive during this extreme rainfall.

Description: A methodology for the experimental modelling of the electric actuators of a multirotor is presented in this work. These actuators are usually brushless DC motors which are driven by electronic speed controllers in an open loop. The duty cycle of a PWM signal, generated by the electronic control unit, is the input of the electronic controller. However, during the control design procedure for the multirotor, it is important to account with a model of the actuators as its dynamical features define the closed-loop performance of the overall aircraft. Hence, a procedure, based on low-cost electronic components, to obtain approximated transfer functions of the actuators of a multirotor is presented. Moreover, as the proposed signal processing algorithms are simple, the computational capabilities of the required embedded system are also low. Given that different control schemes require different information from the actuator, two models were obtained: a duty cycle vs. angular velocity transfer function and a duty cycle vs. consumed current transfer function. The effectivity of the proposal is validated with experimental results on common electric actuators of a multirotor.

Description: The highly nonlinear and coupling characteristics of a flexible air-breathing hypersonic vehicle create great challenges to its flight control design. A unique parameter adaptive nonsingular terminal sliding mode method is proposed for longitudinal control law design of a flexible coupling air-breathing hypersonic vehicle. This method uses adaptive reaching law gain instead of the additional adaptive compensation term to handle the uncertainty to improve robustness. The stability of the close loop system is proved via a Lyapunov way. The longitudinal tracking control law for velocity and angle of attack is designed based on a rigid dynamic model of a flexible air-breathing hypersonic vehicle. A strong coupling model of the same vehicle, considering aerodynamic-scramjet engine-flight dynamic-elastic couplings, is established as the verification platform of the designed control law. The remarkable differences of flight dynamic characteristics between this strong coupling model and the rigid body model can be seen, which mean the controller needs to endure very great uncertainty, unmodeled dynamics, and other types of internal disturbance. Simulation results based on the coupling model demonstrate that the designed control law has good performance and acceptable robustness.

Description: Water hyacinths pose serious challenges to humanity and the environment. Considering the enormity of the menace associated with the growth and spread of the plant and the difficulty in achieving a single, generally acceptable control method, it is becoming increasingly imperative to explore the potentials of the plant. New water hyacinth-related articles are regularly being published. Recently published articles about the plant were accessed, and the information in these articles is presented in the context of the pros and cons of the plant. Some of the benefits that can be derived from the plant include biogas and biofuel production, medicinal functions, vermicomposting, compost production, and bioremediation. However, clogging of waterways, obstruction of water transportation, and fishing activities; breeding grounds for pests and diseases; and reduction of water quality, loss of biodiversity, and economic downturn in areas invaded by the plant are problems associated with it. The peculiarity in the invasiveness of each situation should determine whether or not the growth of the plant is a problem, especially if the opportunity to harness the potentials of the plant exists. There are three major methods for controlling the plants when control becomes inevitable: mechanical, chemical, and biological. To achieve the best control, integrating two or more control methods is advised.

Description: A nonlinear energy sink (NES) is used to suppress panel flutter. A nonlinear aeroelastic model for a two-dimensional flat panel with an NES in supersonic flow is established using the Galerkin method. First-order piston aerodynamic theory is adopted to build the aerodynamic load. The effects of NES parameters on flutter boundaries of the panel are investigated using Lyapunov’s indirect method. The mechanism of the NES suppression of panel flutter is studied through energy analysis. Effects of NES parameters on aeroelastic responses of the panel are obtained, and a design technique is adopted to find a suitable combination of parameter values of the NES that suppresses the panel flutter effectively. Results show that the NES can increase or reduce the onset dynamic pressure of the panel flutter and it can reduce the aeroelastic response amplitude effectively within a certain range of dynamic pressure behind the onset dynamic pressure. The installation position of the NES depends on the direction of the airflow. The robust characteristics should be considered to find the suitable combination of parameter values of the NES.

Description: Bacterial infections are responsible for a large number of deaths every year worldwide. On average, 80% of the African population cannot afford conventional drugs. Moreover, many synthetic antibiotics are associated with side effects and progressive increase in antimicrobial resistance. Currently, there is growing interest in discovering new antibacterial agents from ethnomedicinal plants. About 60% of the population living in developing countries depends on herbal drugs for healthcare needs. This study involved the screening of Centella asiatica commonly used by herbal medicine practitioners in Kisii County to treat symptoms related to bacterial infections. Standard bioassay methods were applied throughout the study. They included preliminary screening of dichloromethane: methanolic extract of Centella asiatica against human pathogenic bacteria including Salmonella typhi ATCC 19430, Escherichia coli ATCC 25922, Shigella sonnei ATCC 25931, Bacillus subtilis ATCC 21332, and Staphylococcus aureus ATCC 25923 using agar disc diffusion, broth microdilution method, and time-kill kinetics with tetracycline as a positive control. Phytochemical screening was carried out to determine the different classes of compounds in the crude extracts. Data were analyzed using one way ANOVA and means separated by Tukey’s test. Dichloromethane: methanolic extract of Centella asiatica was screened against the selected bacterial strains. Time-kill kinetic studies of the extracts showed dose- and time-dependent kinetics of antibacterial properties. Phytochemical screening of the DCM-MeOH extract revealed the presence of alkaloids, flavonoids, phenolics, terpenoids, cardiac glycosides, saponins, steroids, and tannins. The present study indicates that the tested plant can be an important source of antibacterial agents and recommends that the active phytoconstituents be isolated, identified, and screened individually for activities and also subjected further for in vivo and toxicological studies.

Description: The scheduling of Earth Observation Satellite (EOS) data transmission is a complex combinatorial optimization problem. With the development of remote sensing applications, a new special requirement named data transmission oriented to topics has appeared. It supposes that the data obtained from each observation activity by satellites belong to certain observation data topics, and every observation data topic has completeness and timeliness requirements. Unless all of the observation data belonging to one topic has been transmitted to the ground before the expected time, the value of the observation data will be decayed sharply and only a part of the rewards (or even no reward) for the data transmission will be obtained. Current researches do not meet the new data topic transmission requirements well. Based on the characteristics of the problem, a mathematic scheduling model is established, and a novel hybrid scheduling algorithm based on evolutionary computation is proposed. In order to further enhance the performance and speed up the convergence process of our algorithm, a domain-knowledge-based mutation operator is designed. Quantitative experimental results show that the proposed algorithm is more effective to solve the satellite observation data topic transmission scheduling problem than that of the state-of-the-art approaches.

Description: The potential advantages of rotating detonation combustion are gradually approved, and it is becoming a stable and controllable energy conversion way adopted to the propulsion devices or ground-engines. This study focuses on the rotating detonation-based turboshaft engine, and the architecture is presented for this form of engine with compatibility between the turbomachinery and rotating detonation combustor being realized. The parametric performance simulation model for the rotating detonation-based turboshaft engine are developed. Further, the potential performance benefits as well as their generation mechanism are revealed, based on the comprehensive performance analysis of the rotating detonation-based turboshaft engine. Comparisons between the rotating detonation turboshaft engine and the conventional one reveal that the former holds significant improvements in specific power, thermal efficiency, and specific fuel consumption at lower compressor pressure ratios, and these improvements decrease with the increase of compressor pressure ratio and increase as turbine inlet temperature increases. The critical compressor pressure ratio corresponding to the disappearance of specific power improvement is higher than that corresponding to the disappearance of thermal efficiency and specific fuel consumption. These critical compressor pressure ratios are positively correlated with flight altitude and negatively correlated with flight velocity. The conductive research conclusion is guidable for the design and engineering application of rotating detonation-based engines.

Description: Parallel mechanisms with redundant actuation are attracting numerous scholars’ research interest due to their inherent advantages. In this paper, an efficient trajectory tracking control scheme for the new redundantly actuated parallel mechanism by integrating force/position hybrid control with the combination of inertia feed-forward control and back propagation (BP) neural network PID control is proposed. The dynamic models including the joint space and task space are formulated explicitly in efficient and compact form by means of the principle of virtual work and d’Alembert formulations. The force/position hybrid control is implemented to perform trajectory tracking and optimize the driving force configuration in MATLAB/Simulink environment, before being applied to an actual parallel mechanism. The illustrative simulation results demonstrate that the force/position hybrid control scheme is available to provide good trajectory tracking performance. Simultaneously, the feasibility of the proposed control scheme is verified by comparison analysis with the aforementioned conventional control method.

Description: Current pyrotechnic separation devices are mainly made of metal materials, limiting the capacity of lightweight design in advanced launching vehicles. With the outstanding mechanical properties, such as high mass-specific strength and modulus, carbon fiber-reinforced polymers (CFRPs) have the potential to replace metal materials in pyrotechnic seperaton devices. However, to improve the seperation reliability of these pyrotechnic separation devices, there still needs further understanding on the the failure mode of CFRP composites under linear shaped charge (LSC). In this paper, cutting tests were carried out on CFRPs for the failure analysis of CFRPs under LSC, and nonlinear finite element analysis (FEA) was performed to characterize the evolution of LSC cutting in CFRPs. According to experimental simulation and numerical simulation, it can be found that the three main failure modes in CERPs while subjected to LSC jet are shear failure, delamination failure, and tensile failure. In the early cutting stage, the initial time of damage of the fiber and the matrix near the shaped charge shows less difference and the laminate is directly separated by the energy of high-speed jet. When the jet velocity decreases, the jet morphology collapses and matrix damages precede into the fiber, which would cause tensile failure mode of CFRPs. Meanwhile, the delamination in low jet speed stages is larger than that in the high jet speed stages. These studies on the failure modes of CFRPs under LSC provide important basis for the future design of CFRP-based pyrotechnic separation devices, which is important to the lightweight design of launching vehicles.

Description: In order to consider the inlet and engine integrated model of supersonic airliner, the dynamic identification and control of inlet normal shock are studied. The research is based on the bleed air flow rate under supersonic conditions. With the two-dimensional CFD model of supersonic inlet, the dynamic and static effects of the bleeding flow rate on the normal shock position were investigated. The transfer function was identified, and simultaneously the paper carried out a comprehensive study of inlet and engine integrated model, which is established based on the inlet shock position model and engine component level model. The relationship between normal shock position and total pressure recovery coefficient has been taken into consideration in this model. Based on the inlet and engine integrated model, the closed-loop control simulation of normal shock position is carried out. The results show that the model could resist the disturbance of the inlet flow and keep the inlet and engine matching operation point stable near the optimal value.

Description: Deflection torque decrease of flexible joint under increasing pressure was normally attributed to the changing shear stress and has not been carefully resolved, which was far from convincing. To systematically investigate the mechanism, the structure characteristics of the flexible joint were analysed under different pressures. It was found that the decrease in deflection torque of the flexible joint was mainly due to the buckling response when it bears the deflection and pressure at the same time. The Riks method was utilized in this paper with the simulation of the buckling process of the flexible joint by ABAQUS. The static Riks method and general method were applied, respectively, to simulate the different pressurization processes at different pre-angles to obtain the rules of swing angle changing with pressure. The spring torque under various pressures was obtained and had a good coherence with the test results. For industrial applications, the concept of container pressure torque and its formula were proposed in this study, which was demonstrated to be of high accuracy. The simulation method and conclusions in this paper will definitely provide the beneficial reference to the design of the flexible joint in high-pressure working environment.

Description: Among agricultural soil amendment that can enhance crop productivity and soil sustainability is biochar. Hence, two-year field experiments were conducted on a sandy loam Alfisol at Owo, southwest Nigeria, to evaluate the effects of biochar produced from hardwood on soil physical and chemical characteristics, erosion potential, and cocoyam (Xanthosoma sagittifolium (L.) Schott) yield. The study was a 2 × 4 factorial experiment with two years (2017 and 2018) and four biochar levels (0 (control), 10, 20, and 30 t ha−1). The treatments were laid out in a randomized complete block design with three replications. Results indicated that biochar application significantly in both years improved yield of cocoyam and soil physical (bulk density, porosity, moisture content, mean weight diameter (MWD) of soil aggregates, dispersion ratio, and infiltration rate) and chemical (soil organic matter, pH, N, P, K, Ca, Mg, and CEC) properties and erosion resistance. Soil characteristics and cocoyam yield improved with level of biochar from 0–30 t ha−1. When 2018 is compared with 2017 in term of soil loss, in the amended plots, 2018 reduced soil loss by 7.4, 20, and 73.5%, respectively, for 10, 20, and 30 t ha−1biochar, whereas there was an increase of 2.7% soil loss in the control plot in 2018 compared with 2017. Therefore, application rate of 30 t ha−1 biochar is considered as suitable for severely degraded soil because this application rate efficiently improves cocoyam yield and soil properties and reduces soil loss.

Description: Numerical simulations are performed to investigate the influence of crosswind on the aerodynamic characteristics of rigid dragonfly-like flapping wings through the solution of the three-dimensional unsteady Navier-Stokes equations. The aerodynamic forces, the moments, and the flow structures of four dragonfly wings are examined when the sideslip angle between the crosswind and the flight direction varied from 0o to 90o. The stability of the dragonfly model in crosswind is analyzed. The results show that the sideslip angle has a little effect on the total time-average lift force but significant influence on the total time-average thrust force, lateral force, and three-direction torques. An increase in the sideslip angle gives rise to a larger total time-average lateral force and yaw moment. These may accelerate the lateral skewing of the dragonfly, and the increased rolling and pitching moments will further aggravate the instability of the dragonfly model. The vorticities and reattached flow on the wings move laterally to one side due to the crosswind, and the pressure on wing surfaces is no longer symmetrical and hence, the balance between the aerodynamic forces of the wings on two sides is broken. The effects of the sideslip angle on each dragonfly wing are different, e.g., has a greater effect on the aerodynamic forces of the hind wings than those of the fore wings. When sensing a crosswind, it is optimal to control the two hind wings of the bionic dragonfly-like micro aerial vehicles.

Description: A roll-pitch seeker has a wide field of view but suffers from a singularity as the sightline coincides with the outer gimbal (OG) axis. In the vicinity of the singularity, the tracking effectiveness is often degraded or even lost due to the high actuation demand on OG, which is known as the zenith pass problem. To solve this problem, this paper first proposes a novel motion model of sightline to predict the singularity in a receding horizon, where the model parameters are identified using a modified recursive least square estimator. And with the singularity predictions as set points, a predictive functional controller is then designed for the OG position control to minimize the tracking error. This novel combination control scheme is validated in MATLAB/Simulink. Simulation results have confirmed that the proposed scheme can significantly mitigate the zenith pass problem and be applied to the real-time tracking process.

Description: Bowel preparation traditionally refers to the removal of bowel contents via mechanical cleansing measures. Although it has been a common practice for more than 70 years, its use is based mostly on expert opinion rather than solid evidence. Mechanical bowel preparation in minimally invasive and vaginal gynecologic surgery is strongly debated, since many studies have not confirmed its effectiveness, neither in reducing postoperative infectious morbidity nor in improving surgeons’ performance. A comprehensive search of Medline/PubMed and the Cochrane Library Database was conducted, for related articles up to June 2019, including terms such as “mechanical bowel preparation,” “vaginal surgery,” “minimally invasive,” and “gynecology.” We aimed to determine the best practice regarding bowel preparation before these surgical approaches. In previous studies, bowel preparation was evaluated only via mechanical measures. The identified randomized trials in laparoscopic approach and in vaginal surgery were 8 and 4, respectively. Most of them compare different types of preparation, with patients being separated into groups of oral laxatives, rectal measures (enema), low residue diet, and fasting. The outcomes of interest are the quality of the surgical field, postoperative infectious complications, length of hospital stay, and patients’ comfort during the whole procedure. The results are almost identical regardless of the procedure’s type. Routine administration of bowel preparation seems to offer no advantage to any of the objectives mentioned above. Taking into consideration the fact that in most gynecologic cases there is minimal probability of bowel intraluminal entry and, thus, low surgical site infection rates, most scientific societies have issued guidelines against the use of any bowel preparation regimen before laparoscopic or vaginal surgery. Nonetheless, surgeons still do not use a specific pattern and continue ordering them. However, according to recent evidence, preoperative bowel preparation of any type should be omitted prior to minimally invasive and vaginal gynecologic surgeries.

Description: Manipulator systems are widely used in payload capture and movement in the ground/space operation due to their dexterous manipulation capability. In this study, a method for identifying the payload parameters of a flexible space manipulator using the estimated system of complex eigenvalue matrix is proposed. The original nonlinear dynamic model of the manipulator is linearized at a selected working point. Subsequently, the system state-space model and corresponding complex eigenvalue parameters are determined by the observer/Kalman filter identification algorithm using the torque input signal of the motor and the vibration output signals of the link. Therefore, the inertia parameters of the payload, that is, the mass and the moment of inertia, can be derived from the identified complex eigenvalue system and mode shapes by solving a least-squares problem. In numerical simulations, the proposed parameter identification method is implemented and compared with the classical recursive least-squares and affine projection sign algorithms. Numerical results demonstrate that the proposed method can effectively estimate the payload parameters with satisfactory accuracy.

Description: Carbon/carbon composites are usually used as a thermal protection material in the nose cap and leading edge of hypersonic vehicles. In order to predict the thermal and ablation response of a carbon/carbon model in a hypersonic aerothermal environment, a multiphysical coupling model is established taking into account thermochemical nonequilibrium of a flow field, heat transfer, and ablation of a material. A mesh movement algorithm is implemented to track the ablation recession. The flow field distribution and ablation recession are studied. The results show that the fluid-thermal-ablation coupling model can effectively predict the thermal and ablation response of the material. The temperature and heat flux in the stationary region of the carbon/carbon model change significantly with time. As time goes on, the wall temperature increases and the heat flux decreases. The ablation in the stagnation area is more serious than in the lateral area. The shape of the material changes, and the radius of the leading edge increases after ablation. The fluid-thermal-ablation coupling model can be used to provide reference for the design of a thermal protection system.

Description: Foreign object damage (FOD) to fan blades has been identified as one of the main factors affecting the safety of aeroengine operation. Numerical simulations are an important means of studying FOD, but the selection of the material’s parameters in modeling is a key problem. In this work, a FOD test was carried out with titanium alloy blades as the sample, and the damage types suffered by the blades subjected to impacts from foreign objects under different conditions are obtained. A blade material test was carried out to obtain its parameters in terms of the Johnson-Cook material model, and finite element models of the impacting foreign objects are constructed. When comparing the test results with the simulated results, excellent correlation between them is found.

Description: Ensete ventricosum is a traditional multipurpose crop mainly used as a staple/co-staple food for over 20 million people in Ethiopia. Despite this, scientific information about the crop is scarce. Three types of food, viz., Kocho (fermented product from scraped pseudostem and grated corm), Bulla (dehydrated juice), and Amicho (boiled corm) can be prepared from enset. These products are particularly rich in carbohydrates, minerals, fibres, and phenolics, but poor in proteins. Such meals are usually served with meat and cheese to supplement proteins. As a food crop, it has useful attributes such as foods can be stored for long time, grows in wide range of environments, produces high yield per unit area, and tolerates drought. It has an irreplaceable role as a feed for animals. Enset starch is found to have higher or comparable quality to potato and maize starch and widely used as a tablet binder and disintegrant and also in pharmaceutical gelling, drug loading, and release processes. Moreover, enset shows high genetic diversity within a population which in turn renders resilience and food security against the ever-changing environmental factors and land use dynamics. Therefore, more research attention and funding should be given to magnify and make wider use of the crop.

Description: The development, deployment, and maintenance of the current space situational awareness (SSA) information system have become increasingly complex. However, researchers cannot flexibly and conveniently apply the research results to practical applications due to the lack of basic research platforms for SSA. Inspired by X as a Service (XaaS), we propose the microservice-based platform for SSA data analytics to provide a scaffold-like platform for researchers. Based on microservice, the architecture for this platform is proposed to meet the requirements of flexible development and loosely coupled deployment. To facilitate the use of the platform, the hybrid data service layer is established to provide basic data for research and the functional service layer is designed to provide services for clients and applications. Due to the massive data processing requirements, the data analysis architecture and processing model, which can easily integrate various user-defined algorithms and significantly improve the computational efficiency, are proposed based on the Lambda architecture. To verify the platform’s effectiveness, two cases are established and implemented. The results show that this platform can provide a convenient, flexible, and efficient platform for the requirements of algorithm integration, experiment, and data display from users and researchers.

Description: In this study, using new approach (laser diffraction + biological dyes), we have demonstrated the decrease of cells viability in vitro in the deuterated growth medium, whereas in the deuterium-depleted medium, there was an increase of cell viability. We have also found that not all dyes are equally sensitive to the D/H ratios in the culture medium (system) as well as to the different cell types (cancer vs normal cells).

Description: A survey of wild edible plants of Gaddi tribes of Himachal Pradesh was carried out in Chamba and Kangra districts of Himachal Pradesh located in Western Himalayas. The inhabitants subsisted primarily on pastoralism and agriculture and have traditional knowledge on wild edible plants. A total of 49 edible plants belonging to 24 families were recorded in the study area. These were commonly used as vegetables, fruits, spices, and chutney. Nearly half of the species belong to Polygonaceae and Rosaceae families. Herbs, shrubs, climbers, and trees form the habit of these plants. The highest proportion of edible species were herbs (29) followed by trees (10), shrubs (8), climber (1), and Morchella esculenta (fungi) (1).

Description: This paper analyzes a case with the patient having focal structural epilepsy by processing electroencephalogram (EEG) fragments containing the “sharp wave” pattern of brain activity. EEG signals were recorded using 21 channels. Based on the fact that EEG signals are time series, an approach has been developed for their analysis using nonlinear dynamics tools: calculating the Lyapunov exponent’s spectrum, multiscale entropy, and Lempel–Ziv complexity. The calculation of the first Lyapunov exponent is carried out by three methods: Wolf, Rosenstein, and Sano–Sawada, to obtain reliable results. The seven Lyapunov exponent spectra are calculated by the Sano–Sawada method. For the observed patient, studies showed that with medical treatment, his condition did not improve, and as a result, it was recommended to switch from conservative treatment to surgical. The obtained results of the patient’s EEG study using the indicated nonlinear dynamics methods are in good agreement with the medical report and MRI data. The approach developed for the analysis of EEG signals by nonlinear dynamics methods can be applied for early detection of structural changes.

Description: Weathercock stability is usually considered essential to achieve normal flight, while the Dutch roll mode stability can still be achieved without weathercock stability which has been algebraically proved. This paper proposed a flight experiment to investigate the characteristics of an airplane with Dutch roll mode stability but no weathercock stability. Firstly, the algebraic analysis based on a standard lateral-directional mode approximation was made to demonstrate the effect of yawing stability derivative on the Dutch roll mode characteristics. The flight experiment was organized after that using a model glider which was modified to have zero but with marginal change on . The convergence of Dutch roll mode in flight meets the algebraic and numerical analysis as expected. However, the difference of handling characteristics between the original and modified configurations indicates some other roles the weathercock stability plays in flight as well as some limitations of utilizing mode criterion in flight quality analysis.

Description: Background. Preconception care (PCC) aims to improve pregnancy and health outcomes of mothers and their offspring. However, there is no adequate evidence of awareness on preconception care in Ethiopia. Therefore, the present study was performed to assess the level of awareness and associated factors of preconception care among currently delivered mothers. Method. A community-based cross-sectional study was conducted among 561 mothers in Northern Ethiopia. Data were collected using a pretested, structured questionnaire. Odds ratio presented with 95% confidence interval, and a value

Description: In order to improve the autonomy of a maneuvered GEO satellite which is a member of a navigation satellite system, an integrated design method of autonomous orbit determination and autonomous control was proposed. A neural network state observer was designed to estimate the state of the GEO satellite, with only the intersatellite ranging information as observations. The controller is determined autonomously by another neural network based on the estimated state and the preset correction trajectory. A gradient descent learning method with a forgetting factor was used to derive the weight updating strategy which can satisfy the system’s stability and real-time performance. A Lyapunov method was used to prove the stability of both the observer and the controller. The neural network observer can reduce the influence of control on autonomous orbit determination. The neural network controller can improve the robustness of the maneuvered GEO satellite. The simulation results show the effectiveness of this method.

Description: The analysis of thermo-structural behaviour is crucial to the nose cap of a hypersonic vehicle under aerothermodynamic loads. Considering chemical nonequilibrium of the flow field, heat transfer, and deformation of the structure, a fluid-thermal-structural coupling model of the typical nose cap was established. The coupling relation between the flow field and nose cap was analyzed. The results show that the fluid-thermal-structural model can effectively predict the response of the nose cap under a hypersonic environment. The highest temperature and the peak of maximum principal stress appear at the front of the nose cap at an initial stage. As time goes on, the highest temperature increases gradually and the peak of maximum principal stress decreases after reaching a certain value. The position of the peak of maximum principal stress gradually moves to the inside of the nose cap and eventually stabilizes. With the increase in the Mach number, the highest temperature and the peak of maximum principal stress of the nose cap increase. The fluid-thermal-structural coupling model can provide guidance for the optimal design of the nose cap of a hypersonic vehicle.

Description: At present, two kinds of shortages exist in the research on cooperative combat. One is that radar detection threat (which cannot be ignored) is rarely considered. The other is that limited efforts have been made on the cooperative penetration trajectories under the conditions of long distance, vast airspace, and wide speed range. In order to offset the shortages of the research on cooperative combat, the penetration trajectory optimization method considering the influence of aircraft radar cross-section (RCS) and the cooperative penetration strategy is proposed in this study. Firstly, the RCS data are calculated by the physical optics (PO) method. The radar detection threat model is established considering the influence of the aircraft RCS. Then, a trajectory optimization framework with the dynamic model, constraint conditions, and optimal objectives is formed. Using the hp-adaptive Radau pseudospectral method, the optimal control problem for a single aircraft flight is solved. Finally, a cooperative penetration strategy is proposed to solve the cooperative penetration problem of multiaircraft. The impact time and angle constraints are given, and the virtual target point is introduced for terminal guidance. Two cases are simulated and verified. Simulation results demonstrate that the proposed method is effective. The single aircraft can effectively penetrate, and the multiaircraft can fulfill the requirement of cooperative impact time and angle under the condition of meeting the minimum threat of radar detection.

Description: The humanitarian damage caused by the unexploded submunitions is one of the hot issues of concern to the international community at present. A portion of the submunition that did not explode was caused by a break at the connection between the ribbon riveting and the fuze. According to the physical structure of the submunition and the trajectory into which it was ejected, we analyzed the forces of the submunition in flight, deduced the related mathematical models, and clarify the key elements of the mechanics. In this paper, the commercial simulation software was used to calculate the mechanical properties of the ribbon. And the variation regularity between drop velocity and straightening force of ribbon are revealed. And the response characteristics of different material ribbon with different sizes of riveting holes and riveting joints under tensile action were simulated. The simulation results show that, in the trajectory environment with 30 m/s~55 m/s typical stream speed, the tensile force of the ribbon is less than 300 N, and the application concentration of the connecting parts of the riveting joint and the ribbon will not cause the failure of the kevlar ribbon, but it will cause the failure of the nylon ribbon. In order to verify the variation of the tension of kevlar ribbons in different trajectory environments, we designed the experimental scheme of tension test of the ribbon straightening section of submunition and conducted experiments. Experimental results and numerical simulation results revealed the same law. This paper provides effective technical support for solving the problem of unexploded submunitions.

Description: Parallel mechanisms with redundant actuation are attracting numerous scholars’ research interest due to their inherent advantages. In this paper, an efficient trajectory tracking control scheme for the new redundantly actuated parallel mechanism by integrating force/position hybrid control with the combination of inertia feed-forward control and back propagation (BP) neural network PID control is proposed. The dynamic models including the joint space and task space are formulated explicitly in efficient and compact form by means of the principle of virtual work and d’Alembert formulations. The force/position hybrid control is implemented to perform trajectory tracking and optimize the driving force configuration in MATLAB/Simulink environment, before being applied to an actual parallel mechanism. The illustrative simulation results demonstrate that the force/position hybrid control scheme is available to provide good trajectory tracking performance. Simultaneously, the feasibility of the proposed control scheme is verified by comparison analysis with the aforementioned conventional control method.

Description: The civil aviation industry is moving toward the more electric aircraft (MEA) which is to use electrical power to meet the load demands on multiple aircraft subsystems which are conventionally driven by other power resources. Thus, there will be introduced a large amount of new electrical power demands which are safety-critical for aircraft’s flight and this may lead the challenge for a reliable and efficient power management problem (PMP): the balance between the aircraft power supply and demands while minimizing the operation costs. To cope with the PMP for civil aircraft under more electric environment, in this paper, we explicitly give a detailed and complete modeling of all power supply resources (fuel and battery) and safety-critical electrical loads and cast the PMP as a mixed-integer nonlinear programming problem; we develop a practical solution methodology for the application on the real civil MEA. The proposed formulation and solution algorithm can give an efficient power schedule result with the minimal fuel and battery operation cost through a smart codispatch between the gas turbine generator, storage devices, and all electrical loads of MEA. Numerical testing results based on one real civil aircraft case demonstrate the economic and operational effectiveness.

Description: Foreign object damage (FOD) to fan blades has been identified as one of the main factors affecting the safety of aeroengine operation. Numerical simulations are an important means of studying FOD, but the selection of the material’s parameters in modeling is a key problem. In this work, a FOD test was carried out with titanium alloy blades as the sample, and the damage types suffered by the blades subjected to impacts from foreign objects under different conditions are obtained. A blade material test was carried out to obtain its parameters in terms of the Johnson-Cook material model, and finite element models of the impacting foreign objects are constructed. When comparing the test results with the simulated results, excellent correlation between them is found.

Description: It is well known that the application of radar is becoming more and more popular with the development of the signal technology progress. This paper lists the current radar signal research, the technical progress achieved, and the existing limitations. According to radar signal respective characteristics, the design and classification of the radar signal are introduced to reflect signal’s differences and advantages. The multidisciplinary processing technology of the radar signal is classified and compared in details referring to adaptive radar signal process, pulse signal management, digital filtering signal mode, and Doppler method. The transmission process of radar signal is summarized, including the transmission steps of radar signal, the factors affecting radar signal transmission, and radar information screening. The design method of radar signal and the corresponding signal characteristics are compared in terms of performance improvement. Radar signal classification method and related influencing factors are also contrasted and narrated. Radar signal processing technology is described in detail including multidisciplinary technology synthesis. Adaptive radar signal process, pulse compression management, and digital filtering Doppler method are very effective technical means, which has its own unique advantages. At last, the future research trends and challenges of technologies of the radar signals are proposed. The conclusions obtained are beneficial to promote the further promotion applications both in theory and practice. The study work of this paper will be useful for choosing more reasonable radar signal processing technology methods.

Description: Deflection torque decrease of flexible joint under increasing pressure was normally attributed to the changing shear stress and has not been carefully resolved, which was far from convincing. To systematically investigate the mechanism, the structure characteristics of the flexible joint were analysed under different pressures. It was found that the decrease in deflection torque of the flexible joint was mainly due to the buckling response when it bears the deflection and pressure at the same time. The Riks method was utilized in this paper with the simulation of the buckling process of the flexible joint by ABAQUS. The static Riks method and general method were applied, respectively, to simulate the different pressurization processes at different pre-angles to obtain the rules of swing angle changing with pressure. The spring torque under various pressures was obtained and had a good coherence with the test results. For industrial applications, the concept of container pressure torque and its formula were proposed in this study, which was demonstrated to be of high accuracy. The simulation method and conclusions in this paper will definitely provide the beneficial reference to the design of the flexible joint in high-pressure working environment.

Description: In order to consider the inlet and engine integrated model of supersonic airliner, the dynamic identification and control of inlet normal shock are studied. The research is based on the bleed air flow rate under supersonic conditions. With the two-dimensional CFD model of supersonic inlet, the dynamic and static effects of the bleeding flow rate on the normal shock position were investigated. The transfer function was identified, and simultaneously the paper carried out a comprehensive study of inlet and engine integrated model, which is established based on the inlet shock position model and engine component level model. The relationship between normal shock position and total pressure recovery coefficient has been taken into consideration in this model. Based on the inlet and engine integrated model, the closed-loop control simulation of normal shock position is carried out. The results show that the model could resist the disturbance of the inlet flow and keep the inlet and engine matching operation point stable near the optimal value.

Description: In this paper, a recent physics-based metaheuristic algorithm, the Colliding Bodies Optimization (CBO), already employed to solve problems in civil and mechanical engineering, is proposed for the optimization of interplanetary trajectories by using both indirect and direct approaches. The CBO has an extremely simple formulation and does not depend on any initial conditions. To test the performances of the algorithm, missions with remarkably different orbital transfer energies are considered: from the simple planar case, as the Earth-Mars orbital transfer, to more energetic ones, like a rendezvous with the asteroid Pallas.

Description: The development, deployment, and maintenance of the current space situational awareness (SSA) information system have become increasingly complex. However, researchers cannot flexibly and conveniently apply the research results to practical applications due to the lack of basic research platforms for SSA. Inspired by X as a Service (XaaS), we propose the microservice-based platform for SSA data analytics to provide a scaffold-like platform for researchers. Based on microservice, the architecture for this platform is proposed to meet the requirements of flexible development and loosely coupled deployment. To facilitate the use of the platform, the hybrid data service layer is established to provide basic data for research and the functional service layer is designed to provide services for clients and applications. Due to the massive data processing requirements, the data analysis architecture and processing model, which can easily integrate various user-defined algorithms and significantly improve the computational efficiency, are proposed based on the Lambda architecture. To verify the platform’s effectiveness, two cases are established and implemented. The results show that this platform can provide a convenient, flexible, and efficient platform for the requirements of algorithm integration, experiment, and data display from users and researchers.

Description: This study develops the real-time maneuver library generation technique for performing aggressive maneuvers of fixed-wing aircraft. Firstly, the general maneuver libraries are defined, and then 7th-order polynomials are used to create the maneuver libraries. The attitude command attitude hold (ACAH) system, the rate command rate hold (RCRH) system, and the speed command speed hold (SCSH) system using the proportional-integral-derivative (PID) control technique are designed to minimize the complexity of the flight control system (FCS) and to reduce the weight and volume of the payload. Moreover, the FCS is used for implementing tactical maneuvers. Finally, flight simulations are implemented for the longitudinal loop and Immelmann-turn maneuvers to check the usefulness of the proposed maneuver library generation technique. This study can affect the development of flight techniques for aircraft tactical maneuvers and the modification of air force operational manuals.

Description: Current pyrotechnic separation devices are mainly made of metal materials, limiting the capacity of lightweight design in advanced launching vehicles. With the outstanding mechanical properties, such as high mass-specific strength and modulus, carbon fiber-reinforced polymers (CFRPs) have the potential to replace metal materials in pyrotechnic seperaton devices. However, to improve the seperation reliability of these pyrotechnic separation devices, there still needs further understanding on the the failure mode of CFRP composites under linear shaped charge (LSC). In this paper, cutting tests were carried out on CFRPs for the failure analysis of CFRPs under LSC, and nonlinear finite element analysis (FEA) was performed to characterize the evolution of LSC cutting in CFRPs. According to experimental simulation and numerical simulation, it can be found that the three main failure modes in CERPs while subjected to LSC jet are shear failure, delamination failure, and tensile failure. In the early cutting stage, the initial time of damage of the fiber and the matrix near the shaped charge shows less difference and the laminate is directly separated by the energy of high-speed jet. When the jet velocity decreases, the jet morphology collapses and matrix damages precede into the fiber, which would cause tensile failure mode of CFRPs. Meanwhile, the delamination in low jet speed stages is larger than that in the high jet speed stages. These studies on the failure modes of CFRPs under LSC provide important basis for the future design of CFRP-based pyrotechnic separation devices, which is important to the lightweight design of launching vehicles.

Description: A neural network-based controller is developed to enable a chaser spacecraft to approach and capture a disabled Environmental Satellite (ENVISAT). This task is conventionally tackled by framing it as an optimal control problem. However, the optimization of such a problem is computationally expensive and not suitable for onboard implementation. In this work, a learning-based approach is used to rapidly generate the control outputs of the controller based on a series of training samples. These training samples are generated by solving multiple optimal control problems with successive iterations. Then, Radial Basis Function (RBF) neural networks are designed to mimic this optimal control strategy from the generated data. Compared with a traditional controller, the neural network controller is able to generate real-time high-quality control policies by simply passing the input through the feedforward neural network.

Description: Background. Meaning in life is one of the psychological domains that is most severely affected in patients with life-threatening illnesses. The importance of meaning-making mandates the development of reliable tools to assess this construct. Steger’s Meaning in Life Questionnaire (MLQ) is one of the most valid and reliable instruments that determines the search for and presence of meaning in life. The present study was conducted to provide psychometric data on the MLQ in a sample of patients with life-threatening illnesses. Methods. The MLQ was completed by 301 patients (aged 20–80 years) diagnosed with life-threatening illnesses (cancer and multiple sclerosis) and referred to hospitals. Confirmatory factor analysis and Pearson’s correlation test were used to determine the construct validity of the questionnaire. Results. The confirmatory factor analysis supported the original two-factor model of the MLQ, comprised of the presence of meaning (five items) and search for meaning (five items). The responses to the MLQ did not differ by sociodemographic factors. Most importantly, contrary to previous findings, the correlation between the two subscales, i.e., search for meaning and presence of meaning, was significant and positive. Conclusion. The results showed that the MLQ is a valid and reliable measure for assessing meaning in life that can be applied in research on meaning in life among other patient populations.

Description: In clinical daily practice, there are situations in which implant sites have vertical and/or horizontal bone defects and often we must improve their morphology and dimensions before fixture insertion. It is crucial to carefully evaluate the surgical site as regards the characteristics of both hard and soft tissues. The orthodontic extrusion technique can be used for nonsurgical augmentation of the implant site as an alternative to traditional regenerative/reparative surgical therapies. The orthodontic extrusion is based on a biological mechanism that uses the portion of periodontal ligament, still present on the root before the tooth extraction, for the increase of hard and soft tissues. In the literature, there is no evidence of common guidelines for this technique but only tips based on personal experience and/or previous studies. The aim of this study was to investigate and to validate the reliability of a new orthodontic extrusion technique (MF Extrusion Technique, by Dr. Mauro Fadda) by means of a retrospective consecutive case-series study. After we have done a review of the literature, we evaluated the X-rays of twelve consecutively treated patients before the orthodontic extrusion (T0) and after the stabilization period (T1), in order to quantify, by two different measurements, area and linear, the bone gain obtained by the application of the new technique. All the patients examined showed a significant increase in bone areas with an average value of 31.575 mm2. The linear bone gain had an average value of 4.63 mm. Data collected were statistically analysed by the Wilcoxon signed-rank test. The results obtained both from area and linear measurements at T0 and at T1 times showed that there was a statistically significant bone gain with .

Description: Brazilian raw propolis samples (brown, green, red, and yellow) were investigated to evaluate the content of three elements of nutritional value (Cu, K, and Se) and three toxic metals (As, Cd, and Pb). The propolis samples (n = 19) were obtained from different regions of Brazil and analysed by atomic absorption spectrometry after microwave-assisted digestion. A descriptive analysis of the variables was carried out, and nonparametric tests (Kruskal–Wallis or Mann–Whitney) were performed to verify the differences in metal contents. The elemental concentrations of the Brazilian propolis were in the following ranges: As