bluuebunny/crossref_metadata_2025 huggingface dataset:
Cooling Effect and Cooling Speed for a Membrane-in-Middle Optomechanical System
Authors: Chen Zhixin , Lin Qing , He Bing
Published: June 2022

Optomechanical systems are suitable for realizing the ground-state cooling of macroscopic objects. Based on a dynamical approach that goes beyond the validity of the standard linearization approach, we simulate the detailed cooling processes for a membrane-in-middle optomechanical system. In addition to the cooling results, we especially study the cooling speed, which is indicated by how soon the first minimum thermal phonon number is reached. Their relevance to the system parameters provides essential knowledge about how to achieve the best and/or fastest cooling under various combinations of different driving fields.
Changes in Diversity and Community Composition of Root Endophytic Fungi Associated with Aristolochia chilensis along an Aridity Gradient in the Atacama Desert
Authors: Guevara-Araya María José , Escobedo Víctor M. , Palma-Onetto Valeria , González-Teuber Marcia
Published: June 2022

Despite the widespread occurrence of fungal endophytes (FE) in plants inhabiting arid ecosystems, the environmental and soil factors that modulate changes in FE diversity and community composition along an aridity gradient have been little explored. We studied three locations along the coast of the Atacama Desert in Chile, in which the plant Aristolochia chilensis naturally grows, and that differ in their aridity gradient from hyper-arid to semi-arid. We evaluated if root-associated FE diversity (frequency, richness and diversity indexes) and community composition vary as a function of aridity. Additionally, we assessed whether edaphic factors co-varying with aridity (soil water potential, soil moisture, pH and nutrients) may structure FE communities. We expected that FE diversity would gradually increase towards the aridity gradient declines, and that those locations that had the most contrasting environments would show more dissimilar FE communities. We found that richness indexes were inversely related to aridity, although this pattern was only partially observed for FE frequency and diversity. FE community composition was dissimilar among contrasting locations, and soil water availability significantly influenced FE community composition across the gradient. The results indicate that FE diversity and community composition associated with A. chilensis relate to differences in the aridity level across the gradient. Overall, our findings reveal the importance of climate-related factors in shaping changes in diversity, structure and distribution of FE in desert ecosystems.
Exogenous Postharvest Application of Calcium Chloride and Salicylic Acid to Maintain the Quality of Broccoli Florets
Authors: El-Beltagi Hossam S. , Ali Marwa Rashad , Ramadan Khaled M. A. , Anwar Raheel , Shalaby Tarek A. , Rezk Adel A. , El-Ganainy Sherif Mohamed , Mahmoud Samy F. , Alkafafy Mohamed , El-Mogy Mohamed M.
Published: June 2022

The importance of broccoli (Brassica oleracea var. italica) consumption has increased in recent years due to its significant amount of anticarcinogenic and antioxidant compounds, as well as its many vitamins. However, broccoli florets are a highly perishable product which rapidly senesce and turn yellow after harvest, resulting in losses in nutritional and bioactive compounds. Thus, in this study, we evaluated the effect of postharvest exogenous of salicylic acid (SA) and calcium chloride (CaCl2) and their combination on the quality of broccoli florets stored at 5 °C for 28 days to minimize the rapid senescence of broccoli florets. Samples treated with 2 mM SA alone or in combination with 2% CaCl2 showed lower weight loss and lower losses of chlorophyll content, vitamin C, phenolic compounds, carotenoids, flavonoids, and glucosinolates compared with the control samples. Additionally, antioxidant activity was maintained by either SA or SA + CaCl2 treatments while peroxidase activity was decreased. For higher quality and lower losses in antioxidant compounds of broccoli florets during refrigerated storage at 5 °C, SA + CaCl2 treatment could be helpful for up to 21 days.
Mung Bean (Vigna radiata) Treated with Magnesium Nanoparticles and Its Impact on Soilborne Fusarium solani and Fusarium oxysporum in Clay Soil
Authors: Abdallah Yasmine , Hussien Marwa , Omar Maha O. A. , Elashmony Ranya M. S. , Alkhalifah Dalal Hussien M. , Hozzein Wael N.
Published: June 2022

The nanotechnology revolution is developing daily all over the world. Soil-borne fungi cause a significant yield loss in mung beans. Our study was performed to identify the impact of different concentrations of MgO nanoparticles (MgONPs) and to assess the prevalence of Fusarium solani (F. solani) and Fusarium oxysporum (F. oxysporum) in mung bean plants under in vivo conditions and, subsequently, the remaining impacts on soil health. In vitro studies revealed that MgONPs could inhibit fungal growth. Mung bean plants treated with MgONPs showed a promotion in growth. The obtained MgONPs were applied to the roots of 14-day-old mung bean plants at a concentration of 100 µg/mL. The application of MgONPs at a concentration of 100 µg/mL caused an increase in mung bean seedlings. Compared to the control treated with water, plants exposed to MgONPs at 100 µg/mL showed improvements (p < 0.05) in shoot fresh weight (28.62%), shoot dry weight (85.18%), shoot length (45.83%), root fresh weight (38.88%), root dry weight (33.33%), root length (98.46%), and root nodule (70.75%). In the greenhouse, the severity of disease caused by F. solani decreased from approximately 44% to 25% and that by F. oxysporum from 39% to 11.4%, respectively. The results of this study confirm that the temporal growth of the soil microbial biomass was partially reduced or boosted following the nanoparticle drenching addition and/or plant infections at higher concentrations of 50 and 100 µg/mL while there was no significant decrease at the lowest concentration (25 µg/mL). The current research helps us to better understand how nanoparticles might be used to prevent a variety of fungal diseases in agricultural fields while avoiding the creation of environmental hazards to soil health.
Comparative Plasticity Responses of Stable Isotopes of Carbon (δ13C) and Nitrogen (δ15N), Ion Homeostasis and Yield Attributes in Barley Exposed to Saline Environment
Authors: Hussain Muhammad Iftikhar , Khan Zafar Iqbal , Farooq Taimoor Hassan , Al Farraj Dunia A. , Elshikh Mohamed Soliman
Published: June 2022

Salinity is a major threat to agricultural productivity worldwide. The selection and evaluation of crop varieties that can tolerate salt stress are the main components for the rehabilitation of salt-degraded marginal soils. A field experiment was conducted to evaluate salinity tolerance potential, growth performance, carbon (δ13C) and nitrogen isotope composition (δ15N), intrinsic water use efficiency (iWUE), harvest index, and yield stability attributes in six barley genotypes (113/1B, 59/3A, N1-10, N1-29, Barjouj, Alanda01) at three salinity levels (0, 7, and 14 dS m−1). The number of spikes m−2 was highest in Alanda01 (620.8) while the lowest (556.2) was exhibited by Barjouj. Alanda01 produced the highest grain yield (3.96 t ha−1), while the lowest yield was obtained in 59/3A (2.31 t ha−1). Genotypes 113/1B, Barjouj, and Alanda01 demonstrate the highest negative δ13C values (−27.10‰, −26.49‰, −26.45‰), while the lowest values were obtained in N1-29 (−21.63‰) under salt stress. The δ15N was increased (4.93‰ and 4.59‰) after 7 and 14 dS m−1 as compared to control (3.12‰). The iWUE was higher in N1-29 (144.5) and N1-10 (131.8), while lowest in Barjouj (81.4). Grain protein contents were higher in 113/1B and Barjouj than other genotypes. We concluded that salt tolerant barley genotypes can be cultivated in saline marginal soils for food and nutrition security and can help in the rehabilitation of marginal lands.
Electrospun Composite Nanofibers for Functional Applications
Authors: Ullah Sana , Hashmi Motahira , Kim Ick Soo
Published: June 2022

Summary of the Special Issue: [...]
Microporous Formation Mechanism of Biaxial Stretching PA6/PP Membranes with High Porosity and Uniform Pore Size Distribution
Authors: Fang Wenxiang , Liang Guixue , Li Jiang , Guo Shaoyun
Published: June 2022

The low porosity and wide pore size distribution of biaxial stretching PP microporous membranes continue to be the primary impediments to their industrial application. To solve this problem, there is a critical and urgent need to study the micropore-forming mechanism of PP membranes. In this research, the interfacial micropore formation mechanism of PA6/PP membranes during biaxial stretching was investigated. PA6/PP membranes containing spherical PA6 and fibrillar PA6 were found to exhibit different interfacial micropore formation mechanisms. Numerous micropores were generated in the PA6/PP membranes, containing PA6 spherical particles via the interface separation between the PP matrix and PA6 spherical particles during longitudinal stretching. Subsequent transverse stretching further expanded the two-phase interface, promoting the breakdown and fibrosis of the PP matrix and forming a spider-web-like microporous structure centered on spherical PA6 particles. In PA6/PP membranes with PA6 fibers, fewer micropores were generated during longitudinal stretching, but the subsequent transverse stretching violently separated the PA6 fibers, resulting in a dense fiber network composed of PA6 fibers interwoven with PP fibers. Crucially, the PA6/PP biaxial stretching of microporous membranes presented an optimized pore structure, higher porosity, narrower pore size distribution, and better permeability than β-PP membranes. Furthermore, this study explored a new approach to the fabrication of high-performance PA6/PP microporous membranes, with good prospects for potential industrial application.
Synthesis of Chitosan-Based Gold Nanoparticles: Antimicrobial and Wound-Healing Activities
Authors: Hashem Amr H. , Shehabeldine Amr M. , Ali Omar M. , Salem Salem S.
Published: June 2022

The global spread of multidrug-resistant bacteria has become a significant hazard to public health, and more effective antibacterial agents are required. Therefore, this study describes the preparation, characterization, and evaluation of gold nanoparticles modified with chitosan (Chi/AuNPs) as a reducing and stabilizing agent with efficient antimicrobial effects. In recent years, the development of an efficient and ecofriendly method for synthesizing metal nanoparticles has attracted a lot of interest in the field of nanotechnology. Colloidal gold nanoparticles (AuNPs) were prepared by the chemical reduction of gold ions in the presence of chitosan (Chi), giving Chi/AuNPs. The characterization of Chi/AuNPs was carried out by transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier-transform infrared (FTIR), and X-ray diffraction (XRD). Chi/AuNPs appeared spherical and monodispersed, with a diameter ranging between 20 to 120 nm. The synergistic effects of AuNPs and Chi led to the disruption of bacterial membranes. The maximum inhibitory impact was seen against P. aeruginosa at 500 µg/mL, with a zone of inhibition diameter of 26 ± 1.8 mm, whereas the least inhibitory effect was reported for S. aureus, with a zone of inhibition diameter of 16 ± 2.1 mm at the highest dose tested. Moreover, Chi/AuNPs exhibited antifungal activity toward Candida albicans when the MIC was 62.5 µg/mL. Cell viability and proliferation of the developed nanocomposite were evaluated using a sulphorhodamine B (SRB) assay with a half inhibitory concentration (IC50) of 111.1 µg/mL. Moreover, the in vitro wound-healing model revealed that the Chi/AuNP dressing provides a relatively rapid and efficacious wound-healing ability, making the obtained nanocomposite a promising candidate for the development of improved bandage materials.
Lignocellulose Extraction from Sisal Fiber and Its Use in Green Emulsions: A Novel Method
Authors: Pirah Sippi , Wang Xiaodong , Javed Muhammad , Simair Keenjhar , Wang Bijia , Sui Xiaofeng , Lu Changrui
Published: June 2022

Regenerated lignocellulose nanofibrils (RLCNFs) have recently piqued the interest of researchers due to their widespread availability and ease of extraction. After dewaxing, we treated sisal fiber with alkali, followed by heating and agitation, to obtain RLCNFs, which were then vacuum oven-dried. We used a variety of characterization techniques, including XRD, SEM, and FT-IR, to assess the effects of the alkali treatment on the sisal fiber. Various characterizations demonstrate that lignocellulose fibrils have been successfully regenerated and contaminants have been removed. In addition, employing the RLCNFs as a stabilizer, stable Pickering emulsions were created. The effects of RLCNF concentration in the aqueous phase and water-to-oil volume ratio on stability were studied. The RLCNFs that have been produced show promise as a stabilizer in Pickering emulsions.
Effects of Phosphate, Red Mud, and Biochar on As, Cd, and Cu Immobilization and Enzymatic Activity in a Co-Contaminated Soil
Authors: Zhang Di , Yan Kaihong , Liu Yanju , Naidu Ravi
Published: June 2022

Arsenic (As), cadmium (Cd), and copper (Cu) are the primary inorganic pollutants commonly found in contaminated soils. The simultaneous stabilization of the three elements is a preferred approach for mixture-contaminated soils which has received extensive research attention. However, few studies have focused on the immobilization efficiency of a single amendment on the three elements. In this study, phosphate, red mud, and biochar were used to remediate As (237.8 mg kg−1), Cd (28.72 mg kg−1), and Cu (366.5 mg kg−1) co-contaminated soil using a 180-day incubation study. The BCR (European Community Bureau of Reference) extraction method, NH4H2PO4–extractable As, and diethylenetriamine penta-acetic acid (DTPA)–extractable Cd and Cu were analyzed at different time intervals. The results indicated that the application of red mud and biochar significantly reduced soil DTPA–Cd and Cu concentrations during the incubation, while the decrease in soil NH4H2PO4–As was much less than that of soil DTPA–Cd and Cu. After 180 days of incubation, the concentrations of NH4H2PO4–As in red mud and biochar treatments decreased by 2.15~7.89% and 3.01~9.63%, respectively. Unlike red mud and biochar, phosphate significantly reduced the concentration of soil DTPA–Cd and Cu, but failed to lower that of As. The BCR extraction method confirmed that red mud and biochar addition increased the reducible fraction of As due to the surface complexes of As with Fe oxide. Canonical correspondence analysis (CCA) demonstrated that soil pH in addition to available As, Cd, and Cu concentrations were the primary factors in driving the changes in soil enzymatic activity. Soil pH showed positive correlation with soil urease and catalase activities, while negative correlation was observed between soil-available As, Cd, and Cu, and soil enzyme activities. This study revealed that it is difficult to simultaneously and significantly reduce the bioavailabilities of soil As, Cd, and Cu using one amendment. Further research on modifying these amendments or applying combined amendments will be conducted, in order to develop an efficient method for simultaneously immobilizing As, Cd, and Cu.
Purification and Identification of an ACE-Inhibitory Peptide from Gracilaria tenuistipitata Protein Hydrolysates
Authors: Su Yu-Jhen , Liao Hung-Ju , Yang Jing-Iong
Published: June 2022

Edible marine species are valuable sources of bioactive peptides. This study investigated the ACE-inhibitory activity of protein hydrolysates from the red algae Gracilaria tenuistipitata. Fifteen groups of protein hydrolysates were prepared by a two-step enzymatic hydrolysis of G. tenuistipitata: initial hydrolysis with several glycolytic enzymes, followed by three separate proteolytic reactions (Alcalase, Neutrase and Flavourzyme) for 2–10 h. Results showed that the hydrolysate GTN4H had the highest ACE-inhibitory activity in vitro. Furthermore, oral administration of GTN4H significantly reduced systolic blood pressure in spontaneously hypertensive rats. Fraction A derived from GTN4H displayed the highest ACE-inhibitory activity among fractions. Further purification of fraction A by RP-HPLC obtained a purified peptide (MW: 1776 Da) with 17 amino acids and 95.4% ACE-inhibitory activity.
On Reassessment of the HWMA Chart for Process Monitoring
Authors: Riaz Muhammad , Ahmad Shabbir , Mahmood Tahir , Abbas Nasir
Published: June 2022

In the recent literature of process monitoring, homogeneously weighted moving average (HWMA) type control charts have become quite popular. These charts are quite efficient for early detection of shifts, especially of smaller magnitudes, in process parameters such as location and dispersion. A recent study pointed out a few concerns related to HWMA charts that mainly relate to its steady-state performance. It needs to be highlighted that the initial studies on HWMA focused only on the zero-state performance of the chart relative to other well-known memory charts. This study reinvestigates the performance of the HWMA chart under zero and steady states at various shifts. Using the Monte Carlo simulation method, a detailed comparative analysis of the HWMA chart is carried out relative to the exponentially weighted moving average (EWMA) chart with time-varying limits. For several values of design parameters, the in-control and out-of-control performance of these charts is evaluated in terms of the average run length (ARL). It has been observed that the structure of the HWMA chart has the ability to safeguard the detection ability and the run-length properties under various delays in process shifts. More specifically, it has been found that HWMA chart is superior to the EWMA chart for several shift sizes under zero state and is capable of maintaining its dominance in case the process experiences a delay in shift. However, the steady-state performance depends on the suitable choice of design parameters. This study provides clear cut-offs where HWMA and EWMA are superior to one another in terms of efficient monitoring of the process parameters.
Optimization of Sporulation Conditions for Bacillus subtilis BSNK-5
Authors: Tian Zhiliang , Hou Lizhen , Hu Miao , Gao Yaxin , Li Danfeng , Fan Bei , Wang Fengzhong , Li Shuying
Published: June 2022

Bacillus subtilis spores have important biological applications; however, high spore-cell densities and sporulation efficiencies in fermentation is poorly reported. This study systematically analyzed the spore densities and formation efficiency of B. subtilis BSNK-5 in different culture substrates. A response surface regression equation was established based on the results of single factor and Box–Behnken experimental designs. The optimal medium formulation, as predicted from the equation, consisted of soluble starch at 3 g·L−1, soybean flour at 12 g·L−1, and MgSO4 at 5 g·L−1. The spore yield reached 2.43 × 109 CFU·mL−1, and the sporulation rate was 83.3%, which was nearly three times higher than before optimization using an optimized medium at 36 °C and 200 rpm for 60 h.
Treatment of Chromium Removal Wastewater from Tanning by a New Coupling Technology
Authors: Liu Zilong , Lei Ming , Chen Guopeng , Yuan Junsheng
Published: June 2022

In this study, the coupling process of flocculation and membrane separation was used to treat tannery chromium removal wastewater, and the experimental results of the different process operating conditions were investigated to optimize the entire process design. First, the wastewater was pretreated by flocculation ultrafiltration (UF), and the produced water could directly enter nanofiltration (NF) for concentration treatment. The removal rates of turbidity, chroma, and chemical oxygen demand (COD) of the pretreated wastewater were 96.5%, 53.7%, and 45.8%, respectively. Then, NF multistage treatment was used to control the freshwater recovery rate to 90%, where the salt content of the primary freshwater was 200–500 mg·L−1, and the salt content of the secondary freshwater was 800–1000 mg·L−1, which all met the reuse standards of the factory. The total dissolved solids (TDS) and COD of the concentrated wastewater were 44,000–46,000 mg·L−1 and 10,000–13,000 mg·L−1, respectively. Finally, electrodialysis (ED) was used to desalinate the wastewater, and the desalination rate after primary ED desalination was 52.2%. Subsequently, by increasing the temperature of the wastewater in the desalination chamber to 31 °C, the wastewater was subjected to two-stage ED to remove the sulfate in the wastewater for the second time, and the total desalination rate reached 61.9%. The results showed that this new coupling process could realize the efficient reuse of chromium removal from tannery wastewater.
Co-Treatment of Landfill Leachate and Liquid Fractions of Anaerobic Digestate in an Industrial-Scale Membrane Bioreactor System
Authors: Annepogu Nitesh Babu , Beese-Vasbender Pascal F. , Himanshu Himanshu , Wolf Christian , Rehorek Astrid
Published: June 2022

The management of the liquid fraction of digestate produced from the anaerobic digestion of biodegradable municipal solid waste is a difficult affair, as its land application is limited due to high ammonium concentrations and the municipal waste that water treatment plants struggle to treat due to high pollutant loads. The amount of leachate and the pollutant load in the leachate produced by landfills usually decreases with the time, which increases the capacity of landfill leachate treatment plants (LLTPs) to treat additional wastewater. In order to solve the above two challenges, the co-treatment of landfill leachate and the liquid fraction of anaerobic digestate in an industrial-scale LLTP was investigated along with the long-term impacts of the liquid fraction of anaerobic digestate on biocoenosis and its impact on LLTP operational expenses. The co-treatment of landfill leachate and liquid fraction of anaerobic digestate was compared to conventional leachate treatment in an industrial-scale LLTP, which included the use of two parallel lanes (Lane-1 and Lane-2). The average nitrogen removal efficiencies in Lane-1 (co-treatment) were 93.4%, 95%, and 92%, respectively, for C/N ratios of 8.7, 8.9, and 9.4. The average nitrogen removal efficiency in Lane-2 (conventional landfill leachate treatment), meanwhile, was 88%, with a C/N ratio of 6.5. The LLTP’s average chemical oxygen demand (COD) removal efficiencies were 63.5%, 81%, and 78% during phases one, two, and three, respectively. As the volume ratios of the liquid fraction of anaerobic digestate increased, selective oxygen uptake rate experiments demonstrated the dominance of heterotrophic bacteria over ammonium and nitrite-oxidising organisms. The inclusion of the liquid fraction of anaerobic digestate during co-treatment did not cause a significant increase in operational resources, i.e., oxygen, the external carbon source, activated carbon, and energy.
Ritual of the Dead: Karbi Chomangkan Festival in Its Cultural Context
Authors: Hansepi Laxmi , Laisram Rena
Published: June 2022

Like most tribal societies, the socio-religious system of the Karbis of Assam also largely conforms to the belief in magic, spirits, and the ancestor cult. The Chomangkan is one of the most important rituals of the Karbis and mirrors their philosophy of life and death. The Karbis believe that the Chomangkan guides the soul of the dead in its journey to the afterlife, but it is not an immediate funeral ritual, and the relatives of the deceased usually take years to perform it on account of its expensive and elaborate nature. An essential aspect of the ritual is the singing of the oral epics Kacharhe Alun and Mosera Kihir, which are compositions that recount the migration history of the Karbis as the dead embarks on its journey to the ‘village of the ancestors’. The Karbis, who are a clan-based society, have been influenced by Hinduism and Christianity in the last few decades, which has led to a synthesis of the new faiths with the traditional belief system. Therefore, Chomangkan has become a rare ritual, which makes its documentation crucial to preserving Karbi history and culture. Using ethnographic research methods, this paper attempts to critically examine continuity and change in the ‘ritual of the dead’, or Chomangkan, practiced among the Karbi community in Assam. It will also provide insights into the ways in which Chomangkan as a community festival offers an opportunity for the clans and sub-clans to express solidarity, symbolizing the integration of the Karbi lineages in the face of a changing cultural context through various periods of its history.
The Multiple Role of Korean Missionaries in the Making of Transnational Belonging
Authors: Kim Hui-yeon
Published: June 2022

For decades, Korean denominations have sent missionaries around the world. While trying to convert people, notably in Southeast Asia, they are currently involved in humanitarian works but also in organizing labor migration and helping migrants during their stay in South Korea. A close study of missionaries’ work reveals the logic underlying the construction of religious transnational networks. Korean missionaries interlace different kinds of ties with various populations of Southeast Asia and adapt their spiritual and material offerings to different situations. This analysis based on multiple fieldwork assessments in Southeast Asia and in South Korea places emphasis on their specific role as transnational actors and on how they use and promote transnational belonging among marginalized populations.
Analysis of Extreme Hydrometeorological Events
Authors: Bonaccorso Brunella , Peres David J.
Published: June 2022

Extreme hydrometeorological events (e [...]
Using Airborne Lidar, Multispectral Imagery, and Field Inventory Data to Estimate Basal Area, Volume, and Aboveground Biomass in Heterogeneous Mixed Species Forests: A Case Study in Southern Alabama
Authors: Brown Schyler , Narine Lana L. , Gilbert John
Published: June 2022

Airborne light detection and ranging (lidar) has proven to be a useful data source for estimating forest inventory metrics such as basal area (BA), volume, and aboveground biomass (AGB) and for producing wall-to-wall maps for validation of satellite-derived estimates of forest measures. However, some studies have shown that in mixed forests, estimates of forest inventory derived from lidar can be less accurate due to the high variability of growth patterns in multispecies forests. The goal of this study is to produce more accurate wall-to-wall reference maps in mixed forest stands by introducing variables from multispectral imagery into lidar models. Both parametric (multiple linear regression) and non-parametric (Random Forests) modeling techniques were used to estimate BA, volume, and AGB in mixed-species forests in Southern Alabama. Models from Random Forests and linear regression were competitive with one another; neither approach produced substantially better models. Of the best models produced from linear regression, all included a variable for multispectral imagery, though models with only lidar variables were nearly as sufficient for estimating BA, volume, and AGB. In Random Forests modeling, the most important variables were those derived from lidar. The following accuracy was achieved for linear regression model estimates: BA R2 = 0.36, %RMSE = 31.26, volume R2 = 0.45, %RMSE = 35.30, and AGB R2 = 0.41, %RMSE = 31.31. The results of this study show that the addition of multispectral imagery is not substantially beneficial for improving estimates of BA, volume, and AGB in mixed forests and suggests that the investigation of other variables to explain forest variability is necessary.
A New Analysis Method for Magnetic Disturbances Possibly Related to Earthquakes Observed by Satellites
Authors: Ouyang Xin-Yan , Wang Yong-Fu , Zhang Xue-Min , Wang Ya-Lu , Wu Ying-Yan
Published: June 2022

Studies on magnetic disturbances in ultralow frequency ranges related to earthquakes observed by satellites are still limited. Based on Swarm satellites, this paper proposes a new analysis method to investigate pre-earthquake magnetic disturbances by excluding some known non-earthquake magnetic effects that are not confined to those caused by intense geomagnetic activity. This method is demonstrated by two earthquake cases. One is an interplate earthquake, and the other is an intraplate earthquake. Magnetic disturbances around these two earthquakes are associated with solar wind and geomagnetic activity indices, electron density and field-aligned currents. Magnetic disturbances several days before earthquakes do not show clear relations with the already known magnetic effects. These nightside disturbances (LT~17/18, ~02), possibly related to earthquakes observed by Swarm satellites, oscillate in the transverse magnetic field below 2 Hz, propagate along the background magnetic field and are mostly linearly polarized.
Estimation of Daily Average Shortwave Solar Radiation under Clear-Sky Conditions by the Spatial Downscaling and Temporal Extrapolation of Satellite Products in Mountainous Areas
Authors: Zhang Yanli , Chen Linhong
Published: June 2022

The downward surface shortwave radiation (DSSR) received by an inclined surface can be estimated accurately based on the mountain radiation transfer model by using the digital elevation model (DEM) and high-resolution optical remote sensing images. However, it is still challenging to obtain the high-resolution daily average DSSR affected by the atmosphere and local topography in mountain areas. In this study, the spatial downscaling and temporal extrapolation methods were explored separately to estimate the high-resolution daily average DSSR under clear-sky conditions based on Himawari-8, Sentinel-2 satellite radiation products and DEM data. The upper and middle reaches of the Heihe River Basin (UM-HRB) and the Laohugou area of Qilian Mountain (LGH) were used as the study areas because there are many ground observation stations in the UM-HRB that are convenient for DSSR spatial downscaling studies and the high-resolution instantaneous DSSR datasets published for the LHG are helpful for DSSR temporal extrapolation studies. The verification results show that both methods of spatial downscaling and temporal extrapolation can effectively estimate the daily average DSSR. A total of 3002 measurements from six observation sites showed that the 50 m downscaled results of the Himawari-8 10-min 5 km radiation products had quite a high correlation with the ground-based measurements from the UM-HRB. The coefficient of determination (R2) exceeded 0.96. The mean bias error (MBE) and the root-mean-squared error (RMSE) were about 41.57 W/m2 (or 8.22%) and 49.25 W/m2 (or 9.73%), respectively. The fifty-two measurements from two stations in the LHG indicated that the temporal extrapolated results of the Sentinel-2 10 m instantaneous DSSR datasets published previously performed well, giving R2, MBE, and RMSE values of 0.65, 41.06 W/m2 (or 7.89%) and 88.90 W/m2 (or 17.07%), respectively. By comparing the estimation results of the two methods in the LHG, it was found that although the temporal extrapolation method of instantaneous high-resolution radiation products can more finely describe the spatial heterogeneity of solar radiation in complex terrain areas, the overall accuracy is lower than that achieved with the spatial downscaling approach.
Deep Learning for SAR Ship Detection: Past, Present and Future
Authors: Li Jianwei , Xu Congan , Su Hang , Gao Long , Wang Taoyang
Published: June 2022

After the revival of deep learning in computer vision in 2012, SAR ship detection comes into the deep learning era too. The deep learning-based computer vision algorithms can work in an end-to-end pipeline, without the need of designing features manually, and they have amazing performance. As a result, it is also used to detect ships in SAR images. The beginning of this direction is the paper we published in 2017BIGSARDATA, in which the first dataset SSDD was used and shared with peers. Since then, lots of researchers focus their attention on this field. In this paper, we analyze the past, present, and future of the deep learning-based ship detection algorithms in SAR images. In the past section, we analyze the difference between traditional CFAR (constant false alarm rate) based and deep learning-based detectors through theory and experiment. The traditional method is unsupervised while the deep learning is strongly supervised, and their performance varies several times. In the present part, we analyze the 177 published papers about SAR ship detection. We highlight the dataset, algorithm, performance, deep learning framework, country, timeline, etc. After that, we introduce the use of single-stage, two-stage, anchor-free, train from scratch, oriented bounding box, multi-scale, and real-time detectors in detail in the 177 papers. The advantages and disadvantages of speed and accuracy are also analyzed. In the future part, we list the problem and direction of this field. We can find that, in the past five years, the AP50 has boosted from 78.8% in 2017 to 97.8 % in 2022 on SSDD. Additionally, we think that researchers should design algorithms according to the specific characteristics of SAR images. What we should do next is to bridge the gap between SAR ship detection and computer vision by merging the small datasets into a large one and formulating corresponding standards and benchmarks. We expect that this survey of 177 papers can make people better understand these algorithms and stimulate more research in this field.
Precise Crop Classification of Hyperspectral Images Using Multi-Branch Feature Fusion and Dilation-Based MLP
Authors: Wu Haibin , Zhou Huaming , Wang Aili , Iwahori Yuji
Published: June 2022

The precise classification of crop types using hyperspectral remote sensing imaging is an essential application in the field of agriculture, and is of significance for crop yield estimation and growth monitoring. Among the deep learning methods, Convolutional Neural Networks (CNNs) are the premier model for hyperspectral image (HSI) classification for their outstanding locally contextual modeling capability, which facilitates spatial and spectral feature extraction. Nevertheless, the existing CNNs have a fixed shape and are limited to observing restricted receptive fields, constituting a simulation difficulty for modeling long-range dependencies. To tackle this challenge, this paper proposed two novel classification frameworks which are both built from multilayer perceptrons (MLPs). Firstly, we put forward a dilation-based MLP (DMLP) model, in which the dilated convolutional layer replaced the ordinary convolution of MLP, enlarging the receptive field without losing resolution and keeping the relative spatial position of pixels unchanged. Secondly, the paper proposes multi-branch residual blocks and DMLP concerning performance feature fusion after principal component analysis (PCA), called DMLPFFN, which makes full use of the multi-level feature information of the HSI. The proposed approaches are carried out on two widely used hyperspectral datasets: Salinas and KSC; and two practical crop hyperspectral datasets: WHU-Hi-LongKou and WHU-Hi-HanChuan. Experimental results show that the proposed methods outshine several state-of-the-art methods, outperforming CNN by 6.81%, 12.45%, 4.38% and 8.84%, and outperforming ResNet by 4.48%, 7.74%, 3.53% and 6.39% on the Salinas, KSC, WHU-Hi-LongKou and WHU-Hi-HanChuan datasets, respectively. As a result of this study, it was confirmed that the proposed methods offer remarkable performances for hyperspectral precise crop classification.
Retina-like Computational Ghost Imaging for an Axially Moving Target
Authors: Zhang Yingqiang , Cao Jie , Cui Huan , Zhou Dong , Han Bin , Hao Qun
Published: June 2022

Unlike traditional optical imaging schemes, computational ghost imaging (CGI) provides a way to reconstruct images with the spatial distribution information of illumination patterns and the light intensity collected by a single-pixel detector or bucket detector. Compared with stationary scenes, the relative motion between the target and the imaging system in a dynamic scene causes the degradation of reconstructed images. Therefore, we propose a time-variant retina-like computational ghost imaging method for axially moving targets. The illuminated patterns are specially designed with retina-like structures, and the radii of foveal region can be modified according to the axial movement of target. By using the time-variant retina-like patterns and compressive sensing algorithms, high-quality imaging results are obtained. Experimental verification has shown its effectiveness in improving the reconstruction quality of axially moving targets. The proposed method retains the inherent merits of CGI and provides a useful reference for high-quality GI reconstruction of a moving target.
RF eigenfingerprints, an Efficient RF Fingerprinting Method in IoT Context
Authors: Morge-Rollet Louis , Le Roy Frédéric , Le Jeune Denis , Canaff Charles , Gautier Roland
Published: June 2022

In IoT networks, authentication of nodes is primordial and RF fingerprinting is one of the candidates as a non-cryptographic method. RF fingerprinting is a physical-layer security method consisting of authenticated wireless devices using their components’ impairments. In this paper, we propose the RF eigenfingerprints method, inspired by face recognition works called eigenfaces. Our method automatically learns important features using singular value decomposition (SVD), selects important ones using Ljung–Box test, and performs authentication based on a statistical model. We also propose simulation, real-world experiment, and FPGA implementation to highlight the performance of the method. Particularly, we propose a novel RF fingerprinting impairments model for simulation. The end of the paper is dedicated to a discussion about good properties of RF fingerprinting in IoT context, giving our method as an example. Indeed, RF eigenfingerprint has interesting properties such as good scalability, low complexity, and high explainability, making it a good candidate for implementation in IoT context.
A Path-Following Controller for Marine Vehicles Using a Two-Scale Inner-Outer Loop Approach
Authors: Maurya Pramod , Morishita Helio Mitio , Pascoal Antonio , Aguiar A. Pedro
Published: June 2022

This article addresses the problem of path following of marine vehicles along straight lines in the presence of currents by resorting to an inner-outer control loop strategy, with due account for the presence of currents. The inner-outer loop control structures exhibit a fast-slow temporal scale separation that yields simple “rules of thumb” for controller tuning. Stated intuitively, the inner-loop dynamics should be much faster than those of the outer loop. Conceptually, the procedure described has three key advantages: (i) it decouples the design of the inner and outer control loops, (ii) the structure of the outer-loop controller does not require exact knowledge of the vehicle dynamics, and (iii) it provides practitioners a very convenient method to effectively implement path-following controllers on a wide range of vehicles. The path-following controller discussed in this article is designed at the kinematic outer loop that commands the inner loop with the desired heading angles while the vehicle moves at an approximately constant speed. The key underlying idea is to provide a seamless implementation of path-following control algorithms on heterogeneous vehicles, which are often equipped with heading autopilots. To this end, we assume that the heading control system is characterized in terms of an IOS-like relationship without detailed knowledge of vehicle dynamics parameters. This paper quantitatively evaluates the combined inner-outer loop to obtain a relationship for assessing the combined system’s stability. The methods used are based on nonlinear control theory, wherein the cascade and feedback systems of interest are characterized in terms of their IOS properties. We use the IOS small-gain theorem to obtain quantitative relationships for controller tuning that are applicable to a broad range of marine vehicles. Tests with AUVs and one ASV in real-life conditions have shown the efficacy of the path-following control structure developed.
Research on Dynamic Measurement Method of Flow Rate in Tea Processing
Authors: Zhao Zhangfeng , Liu Gaohong , Wang Yueliang , Peng Jiyu , Qiao Xin , Zhong Jiang
Published: June 2022

Tea flow rate is a key indicator in tea production and processing. Due to the small real−time flow of tea leaves on the production line, the noise caused by the transmission system is greater than or close to the real signal of tea leaves. This issue may affect the dynamic measurement accuracy of tea flow. Therefore, a variational mode decomposition combined with a wavelet threshold (VMD−WT) denoising method is proposed to improve the accuracy of tea flow measurement. The denoising method of the tea flow signal based on VMD−WT is established, and the results are compared with WT, VMD, empirical mode decomposition (EMD), and empirical mode decomposition combined with wavelet threshold (EMD−WT). In addition, the dynamic measurement of different tea flow in tea processing is carried out. The result shows that the main noise of tea flow measurement comes from mechanical vibration. The VMD−WT method can effectively remove the noise in the tea dynamic weighing signal, and the denoising performance is better than WT, VMD, EMD, and EMD−WT methods. The average cumulative measurement accuracy of the tea flow signal based on the VMD−WT algorithm is 0.88%, which is 55% higher than that before denoising. This study provides an effective method for dynamic and accurate measurement of tea flow and offers technical support for digital control of the tea processing.
Multi-Modal Vehicle Trajectory Prediction by Collaborative Learning of Lane Orientation, Vehicle Interaction, and Intention
Authors: Tian Wei , Wang Songtao , Wang Zehan , Wu Mingzhi , Zhou Sihong , Bi Xin
Published: June 2022

Accurate trajectory prediction is an essential task in automated driving, which is achieved by sensing and analyzing the behavior of surrounding vehicles. Although plenty of research works have been invested in this field, it is still a challenging subject due to the environment’s complexity and the driving intention uncertainty. In this paper, we propose a joint learning architecture to incorporate the lane orientation, vehicle interaction, and driving intention in vehicle trajectory forecasting. This work employs a coordinate transform to encode the vehicle trajectory with lane orientation information, which is further incorporated into various interaction models to explore the mutual trajectory relations. Extracted features are applied in a dual-level stochastic choice learning to distinguish the trajectory modality at both the intention and motion levels. By collaborative learning of lane orientation, interaction, and intention, our approach can be applied to both highway and urban scenes. Experiments on the NGSIM, HighD, and Argoverse datasets demonstrate that the proposed method achieves a significant improvement in prediction accuracy compared with the baseline.
Melting upon Coalescence of Solid Nanoparticles
Authors: Darvishi Kamachali Reza
Published: June 2022

The large surface-to-volume ratio of nanoparticles is understood to be the source of many interesting phenomena. The melting temperature of nanoparticles is shown to dramatically reduce compared to bulk material. Yet, at temperatures below this reduced melting point, a liquid-like atomic arrangement on the surface of nanoparticles is still anticipated to influence its properties. To understand such surface effects, here, we study the coalescence of Au nanoparticles of various sizes using molecular dynamics simulations. Analysis of the potential energy and Lindemann index distribution across the nanoparticles reveals that high-energy, high-mobility surface atoms can enable the coalescence of nanoparticles at temperatures much lower than their corresponding melting point. The smaller the nanoparticles, the larger the difference between their melting and coalescence temperatures. For small enough particles and/or elevated enough temperatures, we found that the coalescence leads to a melting transition of the two nominally solid nanoparticles, here discussed in relation to the heat released due to the surface reduction upon the coalescence and the size dependence of latent heat. Such discontinuous melting transitions can lead to abrupt changes in the properties of nanoparticles, important for their applications at intermediate temperatures.
The Relationship between Cyberbullying and Mental Health among University Students
Authors: Ali Sayed Ibrahim , Shahbuddin Nurjahan Begum
Published: June 2022

Background: The term ‘cyberbullying’ is linked to traditional bullying, and both refer to oppression. This study aimed to determine the overall effects of cyberbullying on mental health among university students of various ages, and to investigate the extent to which victims (students) directed less attention and focus towards their academic achievement. Methods: The participants in this study were 326 male and female students from King Faisal University in the Al-Ahsa Governorate. The researchers in this study employed the descriptive correlative approach. Results: The study’s findings revealed that there were substantial variations in the categories of sex, academic specialty (medical and non-medical students), and family economic status, in relation to cyberbullying surveys. In addition, there was a significant negative relationship between cyberbullying and mental health. Conclusions: It is highly recommended that, in order to prevent cyberbullying, people of all generations need to be made aware of it via specific programs in different public areas, for example, in schools, colleges, and malls, and on social media.
Public Transport Affordability Evaluation for Addis Ababa City
Authors: Mohammed Murad , Senadheera Sanjaya
Published: June 2022

The affordability of transportation services refers to the financial burden the travelers bear in purchasing such services. Key factors that affect affordability include travel demand, supply, competitiveness, quality, and cost of transport services. Surveys indicate that transport users consider affordability an important planning objective, but conventional transport planning tends to give little consideration to it. Public transport is one of the key instruments to bring sustainable mobility to cities, and its supply and quality must be maintained at acceptable levels for it to be a desirable mode of transportation. The ever-increasing demand for mass mobility resulting from rapid population growth and extended urbanization in the City of Addis Ababa calls for the provision of good quality, affordable urban public transport services. In this research, the affordability of public transport of Addis Ababa was studied. The majority of data were acquired from the City Transport Bureau. The analysis of data produced a city-wide observed affordability index (Affo) of 14.13% with the highest and lowest values of 32.11 and 3.69% for Q5 and Q1, respectively. The difference between potential and observed affordability is 28.34%. This indicates that, to reach the same motorized trip rates as the third quintile, those households in the lowest quintile need to increase their transport expenditure by 28.34% in Addis Ababa. The results of this study show that the dual affordability metric both in terms observed and potential affordability can provide an effective basis to improve the affordability of public transport in the city by adopting measures that are customized according to regional characteristics at the sub-city level.