bluuebunny/crossref_metadata_2025 huggingface dataset:
Polybenzoxazine Resins with Cellulose Phosphide: Preparation, Flame Retardancy and Mechanisms
Authors: Li Hui , Sun Zhangmei , Zhao Chunxia , Li Yuntao , Xiang Dong , Wu Yuanpeng , Wei Jixuan , Que Yusheng
Published: December 2021

Phosphated cellulose (PCF) was synthesized based on urea, phosphated acid and cellulose. The structure of the PCF was confirmed by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy coupled with the Energy Dispersive Spectrometer (SEM-EDS). Benzoxazine (Ba)/PCF hybrid materials were fabricated and thermally cured to prepare polybenzoxazine composites (PBa/PCF). The effects of PCF on the curing temperature of Ba were analyzed through differential scanning calorimetry (DSC). The thermogravimetric (TGA) results demonstrated an increased char residue of 50% for the PBa composites incorporating PCF-5% compared with the pure PBa. The peak heat release rate (PHRR) and total heat release (THR) values of the PBa/PCF-5% composites clearly decreased by 58.1% and 16.5% compared to those of the pristine PBa. The smoke released from the PBa/PCF system significantly reduced with the loading of PCF. Moreover, the limited oxygen index (LOI) and vertical burning test level (UL-94) of PBa/PCF-5% reached up to 31 and V0. The flame retardant mechanism of the PCF in the PBa matrix was investigated TG-FTIR and char residues analysis. Finally, the dynamical mechanical analysis (DMA) results demonstrated that the Tg of the PBa/PCF composites was approximately 230 °C, which does not affect further applications of PBa composites.
Traffic Control Prediction Design Based on Fuzzy Logic and Lyapunov Approaches to Improve the Performance of Road Intersection
Authors: Jafari Sadiqa , Shahbazi Zeinab , Byun Yung-Cheol
Published: December 2021

Due to the increasing use of private cars for urbanization and urban transport, the travel time of urban transportation is increasing. People spend a lot of time in the streets, and the queue length of waiting increases accordingly; this has direct effects on fuel consumption too. Traffic flow forecasts and traffic light schedules were studied separately in the urban traffic system. This paper presents a new stable TS (Takagi–Sugeno) fuzzy controller for urban traffic. The state-space dynamics are utilized to formulate both the vehicle’s average waiting time at an isolated intersection and the length of queues. A fuzzy intelligent controller is designed for light control based upon the length of the queue, and eventually, the system’s stability is proved using the Lyapunov theorem. Moreover, the input variables are the length of queue and number of input or output vehicles from each lane. The simulation results describe the appearance of the proposed controller. An illustrative example is also given to show the proposed method’s effectiveness; the suggested method is more efficient than both the conventional fuzzy traffic controllers and the fixed time controller.
Laser Peening Analysis of Aluminum 5083: A Finite Element Study
Authors: Tajyar Ali , Holtham Noah , Brooks Nicholas , Hackel Lloyd , Sherman Vincent , Beheshti Ali , Davami Keivan
Published: December 2021

In this research, a finite element (FE) technique was used to predict the residual stresses in laser-peened aluminum 5083 at different power densities. A dynamic pressure profile was used to create the pressure wave in an explicit model, and the stress results were extracted once the solution was stabilized. It is shown that as power density increases from 0.5 to 4 GW/cm2, the induced residual stresses develop monotonically deeper from 0.42 to 1.40 mm. However, with an increase in the power density, the maximum magnitude of the sub-surface stresses increases only up to a certain threshold (1 GW/cm2 for aluminum 5083). Above this threshold, a complex interaction of the elastic and plastic waves occurring at peak pressures above ≈2.5 Hugoniot Elastic Limit (HEL) results in decreased surface stresses. The FE results are corroborated with physical experiments and observations.
An Integrated Wireless Multi-Sensor System for Monitoring the Water Quality of Aquaculture
Authors: Lin Jen-Yung , Tsai Huan-Liang , Lyu Wei-Hong
Published: December 2021

Water temperature, pH, dissolved oxygen (DO), electrical conductivity (EC), and salinity levels are the critical cultivation factors for freshwater aquaculture. This paper proposes a novel wireless multi-sensor system by integrating the temperature, pH, DO, and EC sensors with an ESP 32 Wi-Fi module for monitoring the water quality of freshwater aquaculture, which acquires the sensing data and salinity information directly derived from the EC level. The information of water temperature, pH, DO, EC, and salinity levels was displayed in the ThingSpeak IoT platform and was visualized in a user-friendly manner by ThingView APP. Firstly, these sensors were integrated with an ESP32 Wi-Fi platform. The observations of sensors and the estimated salinity from the EC level were then transmitted by a Wi-Fi network to an on-site Wi-Fi access point (AP). The acquired information was further transmitted to the ThingSpeak IoT and displayed in the form of a web-based monitoring system which can be directly visualized by online browsing or the ThingView APP. Through the complete processes of pre-calibration, in situ measurement, and post-calibration, the results illustrate that the proposed wireless multi-sensor IoT system has sufficient accuracy, reliable confidence, and a good tolerance for monitoring the water quality of freshwater aquaculture.
Research on the Viscosity-Temperature Properties and Thermal Stability of Stabilized Rubber Powder Modified Asphalt
Authors: Ma Qingwei , Guo Zhongyin , Guo Ping , Yang Fayong , Li Haibin
Published: December 2021

A stabilized rubber powder-modified asphalt was provided for the field of rubber asphalt, and the optimal blending amount of stable rubber powder was determined from indicators, such as penetration, penetration index, ductility, softening point, and viscosity at 135 °C. The viscoelastic curve was measured, and the thermal storage stability test showed that the stabilized rubber powder-modified asphalt has significant thermal storage stability. The specific surface area, scanning electron microscope, and differential scanning calorimeters were used to analyze the dispersion state and aggregation state of the rubber powder particles in the stabilized rubber powder-modified asphalt, etc. The swelling state and reaction mechanism of the rubber powder in the stabilized rubber powder-modified asphalt have been characterized. The results show that the temperature sensitivity of the asphalt was improved after the stabilized rubber powder was added. The content of the stabilized rubber powder was determined to be 30%, which effectively reduces the viscosity at 135 °C, and the workability is improved; the impact of rubber powder-modified asphalt was less than that of ordinary rubber asphalt, but the temperature should be strictly controlled to ensure the viscosity of stable rubber powder-modified asphalt; the specific surface area comparison test shows that the stable rubber powder has better performance than ordinary rubber powder and asphalt matrix. The advantage of having a larger contact area enhances the compatibility of stabilized rubber powder with asphalt; scanning electron microscopy and differential scanning calorimeters test results show that the stable rubber powder-modified asphalt is mainly based on the compatibility mechanism, and a series of processes, such as oil absorption swelling-high temperature shear-compatible dispersion, occur.
Heavy Metal Contamination and Human Health Implications in the Chan Thnal Reservoir, Cambodia
Authors: Chheang Lita , Thongkon Nisakorn , Sriwiriyarat Tongchai , Thanasupsin Sudtida Pliankarom
Published: December 2021

Chan Thnal reservoir, built during the Pol Pot period, is the major water source for the people in Krang Chek commune, Kampong Speu Province, Cambodia. Metal pollution caused by agricultural activities, improper wastewater treatment, and municipal waste disposal poses serious environmental health problems. In this study, the concentrations of four potential toxic metals (i.e., Cd, Cu, Pb, and Zn) from six locations across the reservoir were investigated both in the water and sediment. The results reflected progressive deterioration and indicated moderate to heavy pollution from the metals. The metal levels in the water were in the order of Zn > Cu > Pb > Cd. The statistical analysis revealed primary sources of heavy metals contamination in the water. Cd, Cu, Zn, and Pb in the water likely originate from anthropogenic activities including agricultural runoff (i.e., the use of fertilizers and pesticides) and urban runoff (i.e., improper wastewater discharge and waste disposal). Among the four metals, the Pb levels in the water significantly exceeded the guideline for drinking water in all locations. The health risk assessment revealed serious non-carcinogenic risks of Pb intake in the children at the age below 10 and infants. Appropriate control and protection strategies are urgently needed to cut off the main Pb exposure pathway in pregnant women, children, and infants.
Is Organic Food Becoming Less Safe? A Longitudinal Analysis of Conventional and Organic Product Recalls
Authors: Chowdhury Mesbahuddin , Castka Pavel , Prajogo Daniel , Zhao Xiaoli , Wood Lincoln C.
Published: December 2021

Organic products are often portrayed as a healthy alternative—grown in a sustainable way, often locally and subject to external certification scrutiny. However, recent high-profile cases of contaminated organic food have raised questions about the risks associated with organic produce: is organic produce becoming less safe and more risky? The context for this investigation is in the realm of food product recalls. Based on 2010–2017 panel data from the US on food product recalls (with 2721 observations), this paper compares the volume of recalls (adjusted for the growth of sales) between conventional and organic food. This paper further addresses two food-related risks: design risk (a risk that is present in the development of food; such as the use of unapproved ingredients or the omission of some ingredients on the food label) and process risk (a risk within the supply chain, such as the contamination of food products with salmonella or E. coli). Further comparison is drawn based on food product type (here the paper distinguishes between processed and unprocessed food). The paper demonstrates that organic products are becoming less safe and that organic products are recalled at a higher rate. In comparison to conventional produce, organic produce is more prone to process risk and far less to design risk. Similar conclusions are reached even when the organic produce is analysed from a product type perspective.
An Economic Risk Analysis in Wind and Pumped Hydro Energy Storage Integrated Power System Using Meta-Heuristic Algorithm
Authors: Singh Nitesh Kumar , Koley Chaitali , Gope Sadhan , Dawn Subhojit , Ustun Taha Selim
Published: December 2021

Due to the restructuring of the power system, customers always try to obtain low-cost power efficiently and reliably. As a result, there is a chance to violate the system security limit, or the system may run in risk conditions. In this paper, an economic risk analysis of a power system considering wind and pumped hydroelectric storage (WPHS) hybrid system is presented with the help of meta-heuristic algorithms. The value-at-risk (VaR) and conditional value-at-risk (CVaR) are used as the economic risk analysis tool with two different confidence levels (i.e., 95% and 99%). The VaR and CVaR with higher negative values represent the system in a higher-risk condition. The value of VaR and CVaR on the lower negative side or towards a positive value side indicates a less risky system. The main objective of this work is to minimize the system risk as well as minimize the system generation cost by optimal placement of wind farm and pumped hydro storage systems in the power system. Sequential quadratic programming (SQP), artificial bee colony algorithms (ABC), and moth flame optimization algorithms (MFO) are used to solve optimal power flow problems. The novelty of this paper is that the MFO algorithm is used for the first time in this type of power risk curtailment problem. The IEEE 30 bus system is considered to analyze the system risk with the different confidence levels. The MVA flow of all transmission lines is considered here to calculate the value of VaR and CVaR. The hourly VaR and CVaR values of the hybrid system considering the WPHS system are reported here and the numerical case studies of the hybrid WPHS system demonstrate the effectiveness of the proposed approach. To validate the presented approach, the results obtained by using the MFO algorithm are compared with the SQP and ABC algorithms’ results.
Profitability Determinants of Unlisted Renewable Energy Companies in Germany—A Longitudinal Analysis of Financial Accounts
Authors: Luts Maria-Kristiine , Savolainen Jyrki , Collan Mikael
Published: December 2021

The fight against a climate crisis has urged nations and the global community to cut emissions and to define ambitious environmental goals. This has highlighted the importance of the renewable energy (RE) industry. Germany has been one of the most active countries in RE adoption. In this vein, the purpose of this research is to study and identify key profitability determinants of unlisted German electricity-producing RE-companies, many of which have been supported by the German Feed-in Tariff (FIT). A multi-year analysis based on panel data from 783 companies for the years 2010–2018 is used. The results show that both company- and industry-specific profitability determinants are statistically significant, but the company-specific determinants seem to be more important. The results shed new light on what drives the profitability of private German RE companies during the period of financial aid from the government and are of use to managers, regulators and investors alike, e.g., when the effects of different regulatory climates and industry environments, as well as states of business life cycle are considered. Furthermore, the implications of this study have wider environmental and economic importance as the performance of the RE companies is critical in achieving the emission targets of the energy industry and ensuring a more sustainable energy production for the future.
Resilience in Vulnerable Small and New Social Enterprises
Authors: Searing Elizabeth A. M.
Published: December 2021

The use of financial ratios in predicting financial vulnerability has a large body of literature, but few studies address resilience and the recovery from financial distress. Further, no vulnerability studies specifically address the needs of small and young social enterprises. This study uses over twenty years of panel data to predict which factors signal the future recovery of small and young social enterprises. There is mixed support for hypotheses found in the literature, and though additional equity and revenue diversification is shown to be beneficial, increased surplus ratios carry implications which vary between financial stressors. Even in a sample of small organizations, we find evidence for the liability of smallness. Implications for practitioners, researchers, and policymakers are discussed.
Reconfigurable Neighborhood—Mechatronisation of the Urban Design
Authors: Dąbrowska-Żółtak Karolina , Wojtowicz Jerzy , Wrona Stefan
Published: December 2021

Today more than half of the world’s population lives in cities not yet ready for the massive growth and adaptation required to meet global urbanization predicted for the next decades. The planning, design, and urban governance must urgently evolve. Future cities should become more efficient, inclusive, and sustainable. The intelligent town we anticipate combines the concepts of new information flow as well as research proposals for the design, upgrade of buildings and municipal infrastructure using robots and mechatronic systems at the scale of dwelling, building, neighborhood, district or town. This article presents the conceptual framework for the role of kinetic and responsive design at the scale of small urban areas, taking into account dynamic adaptation to users’ needs and changing environmental conditions across a day, week, month and year.
Ecosystem Service Modelling to Support Nature-Based Flood Water Management in the Vietnamese Mekong River Delta
Authors: Dang Nguyet Anh , Benavidez Rubianca , Tomscha Stephanie Anne , Nguyen Ho , Tran Dung Duc , Nguyen Diep Thi Hong , Loc Ho Huu , Jackson Bethanna Marie
Published: December 2021

Deltas are among the most productive and diverse global ecosystems. However, these regions are highly vulnerable to natural disasters and climate change. Nature-based solutions (Nbs) have been increasingly adopted in many deltas to improve their resilience. Among decision support tools, assessment of ecosystem services (ES) through spatially explicit modelling plays an important role in advocating for Nbs. This study explores the use of the Land Utilisation and Capability Indicator (LUCI) model, a high-resolution model originally developed in temperate hill country regions, to map changes in multiple ecosystem services (ES), along with their synergies and trade-offs, between 2010 and 2018 in the Vietnamese Mekong Delta (VMD). In so doing, this study contributes to the current knowledge in at least two aspects: high-resolution ES modelling in the VMD, and the combination of ES biophysical and economic values within the VMD to support Nbs implementation. To date, this is the highest resolution (5 by 5 m) ES modelling study ever conducted in the VMD, with ~1500 million elements generated per ES. In the process of trialling implementations of LUCI within the VMD’s unique environmental conditions and data contexts, we identify and suggest potential model enhancements to make the LUCI model more applicable to the VMD as well as other tropical deltaic regions. LUCI generated informative results in much of the VMD for the selected ES (flood mitigation, agriculture/aquaculture productivity, and climate regulation), but challenges arose around its application to a new agro-hydrological regime. To address these challenges, parameterising LUCI and reconceptualising some of the model’s mechanisms to specifically account for the productivity and flood mitigation capability of water-tolerant crops as well as flooding processes of deltaic regions will improve future ES modelling in tropical deltaic areas. The ES maps showed the spatial heterogeneity of ES across the VMD. Next, to at least somewhat account for the economic drivers which need to be considered alongside biophysical valuations for practical implementations of ES maps for nature-based solutions (Nbs) in the upstream VMD, economic values were assigned to different parcels using a benefit transfer approach. The spatially explicit ES economic value maps can inform the design of financing incentives for Nbs. The results and related work can be used to support the establishment of Nbs that ultimately contribute to the security of local farmers’ livelihoods and the sustainability of the VMD.
Simulation-Optimization for the Planning of Off-Site Construction Projects: A Comparative Study of Recent Swarm Intelligence Metaheuristics
Authors: Hussein Mohamed , Eltoukhy Abdelrahman E. E. , Darko Amos , Eltawil Amr
Published: December 2021

Off-site construction is a modern construction method that brings many sustainability merits to the built environment. However, the sub-optimal planning decisions (e.g., resource allocation, logistics and overtime planning decisions) of off-site construction projects can easily wipe away their sustainability merits. Therefore, simulation modelling—an efficient tool to consider the complexity and uncertainty of these projects—is integrated with metaheuristics, developing a simulation-optimization model to find the best possible planning decisions. Recent swarm intelligence metaheuristics have been used to solve various complex optimization problems. However, their potential for solving the simulation-optimization problems of construction projects has not been investigated. This research contributes by investigating the status-quo of simulation-optimization models in the construction field and comparing the performance of five recent swarm intelligence metaheuristics to solve the stochastic time–cost trade-off problem with the aid of parallel computing and a variance reduction technique to reduce the computation time. These five metaheuristics include the firefly algorithm, grey wolf optimization, the whale optimization algorithm, the salp swarm algorithm, and one improved version of the well-known bat algorithm. The literature analysis of the simulation-optimization models in the construction field shows that: (1) discrete-event simulation is the most-used simulation method in these models, (2) most studies applied genetic algorithms, and (3) very few studies used computation time reduction techniques, although the simulation-optimization models are computationally expensive. The five selected swarm intelligence metaheuristics were applied to a case study of a bridge deck construction project using the off-site construction method. The results further show that grey wolf optimization and the improved bat algorithm are superior to the firefly, whale optimization, and salp swarm algorithms in terms of the obtained solutions’ quality and convergence behaviour. Finally, the use of parallel computing and a variance reduction technique reduces the average computation time of the simulation-optimization models by about 87.0%. This study is a step towards the optimum planning of off-site construction projects in order to maintain their sustainability advantages.
Asymmetric Data Hiding for Compressed Images with High Payload and Reversibility
Authors: Lin Juan , Chang Chin-Chen , Horng Ji-Hwei
Published: December 2021

Hiding secret data in digital images is an attractive topic in the information security research area. Because the data-embedded stego image looks exactly the same as a regular image, transmitting secret data with stego images does not draw the attention of eavesdroppers, thus fulfilling the goal of information security. Many reversible data hiding (RDH) methods for absolute moment block truncation coding (AMBTC) compressed images have been proposed. These methods hide secret data in an AMBTC-compressed image to produce a stego image and transmit it to the recipient. Upon receiving the stego image, the recipient can extract the secret data and recover the AMBTC-compressed image. In this paper, we propose an RDH scheme for AMBTC-compressed images with an asymmetric embedding rule. Using the AMBTC-compressed version as the basis, the proposed embedding scheme always modifies a pixel value toward its original value with a step size (bitrate) proportional to the gap width. Therefore, the visual quality of the stego image is better than the referred AMBTC version. Additionally, as a result of the adaptive bitrate strategy, the data embedding capacity of the proposed scheme outperforms that of state-of-the-art methods. The security of the resulting stego images was also tested by RS-steganalysis. Experimental results show that the overall performance of the proposed scheme is satisfactory. We revised it, please confirm.
Development of a Method for Evaluating the Technical Condition of a Car’s Hybrid Powertrain
Authors: Bazhinov Oleksiy , Gerlici Juraj , Kravchenko Oleksandr , Haiek Yevhen , Bazhynova Tetiana , Zaverukha Ruslan , Kravchenko Kateryna
Published: December 2021

The article presents the results of a study performed and substantiated based on the principles of a new method of diagnostics of technical conditions of a hybrid powertrain regardless of the structural diagram and design features of a hybrid vehicle. The presented new technology of the diagnostics of hybrid powertrains allows an objective complex assessment of their technical condition by diagnostic parameters in contrast to existing diagnostic methods. In the proposed method, a mechanism for the general standardization of diagnostic parameters has been developed as well as for determining the numerical values of the parameters of the powertrain. The control subset was used to control the learning error. As a result of debugging the system, the scatter of experimental and calculated points has decreased, which confirms the quality of debugging the tested fuzzy model. As a result of training the artificial neural network, the standard deviation of the error in the control sample was 0.012·Pk. A symmetry method of diagnostics of the technical state of a hybrid propulsion system was developed based on the concept of a neural network together with a neuro-fuzzy control with an adaptive criteria based on the method of training a neural network with reinforcement. The components of the vector functional include the criteria for control accuracy, the use of traction battery energy, and the degree of toxicity of exhaust gases. It is proposed to use the principle of symmetry of the guaranteed result and the linear inversion of the vector criterion into a supercriterion to determine the technical state of a hybrid powertrain on a set of Pareto-optimal controls under unequal conditions of optimality.
Indoxyl Sulfate Elevated Lnc-SLC15A1-1 Upregulating CXCL10/CXCL8 Expression in High-Glucose Endothelial Cells by Sponging MicroRNAs
Authors: Huang Yu-Chin , Tsai Tzu-Chun , Chang Chia-Hsin , Chang Kuo-Ting , Ko Pin-Hao , Lai Liang-Chuan
Published: December 2021

Cardiovascular disease (CVD) is the leading cause of mortality in diabetes mellitus (DM). Immunomodulatory dysfunction is a primary feature of DM, and the emergence of chronic kidney disease (CKD) in DM abruptly increases CVD mortality compared with DM alone. Endothelial injury and the accumulation of uremic toxins in the blood of DM/CKD patients are known mechanisms for the pathogenesis of CVD. However, the molecular factors that cause this disproportional increase in CVD in the DM/CKD population are still unknown. Since long non-protein-coding RNAs (lncRNAs) play an important role in regulating multiple cellular functions, we used human endothelial cells treated with high glucose to mimic DM and with the uremic toxin indoxyl sulfate (IS) to mimic the endothelial injury associated with CKD. Differentially expressed lncRNAs in these conditions were analyzed by RNA sequencing. We discovered that lnc-SLC15A1-1 expression was significantly increased upon IS treatment in comparison with high glucose alone, and then cascaded the signal of chemokines CXCL10 and CXCL8 via sponging miR-27b, miR-297, and miR-150b. This novel pathway might be responsible for the endothelial inflammation implicated in augmenting CVD in DM/CKD and could be a therapeutic target with future clinical applications.
Impact of Vaccination on the Sense of Security, the Anxiety of COVID-19 and Quality of Life among Polish. A Nationwide Online Survey in Poland
Authors: Babicki Mateusz , Malchrzak Wojciech , Hans-Wytrychowska Anna , Mastalerz-Migas Agnieszka
Published: December 2021

The pandemic state has a destructive effect on the human psyche and induces fear for one’s own health. By reducing the risk of severe COVID-19, vaccination may indirectly improve the mental state. This study aims to assess the effects of vaccination on respondents’ mental well-being, their attitudes towards adherence to government recommendations limiting viral transmission, and to identify factors that may influence the decision to get vaccinated. The survey took the form of the authors’ own, fully voluntary, anonymous, online questionnaire. Standardised psychometric tools were used in the survey: Generalised Anxiety Disorder Assessment (GAD-7) and Manchester Short Assessment of Quality of Life (MANSA). The survey involved 1696 respondents, the vast majority of whom were women, and were aged 18–29. The vaccination status was declared by 1677 respondents (98.9%), 430 (25.4%) of whom were vaccinated with at least one dose of vaccine, while 303 (17.9%) respondents were not only unvaccinated at all, and declared no intention to get vaccinated in the future. Fully vaccinated individuals were found to have lower levels of anxiety, higher MANSA scores and lower subjective anxiety about being infected with COVID-19 than those awaiting vaccination or those with an incomplete vaccination regimen (one dose). Those who are not willing to get vaccinated have the lowest sense of anxiety and fear of being infected and they have the lowest adherence to government recommendations limiting SARS-CoV-2 transmission. Conclusions: COVID-19 vaccination reduces the level of anxiety about being infected and anxiety due to COVID-19 disease in people from the immediate environment. Those who are not willing to get vaccinated have extreme attitudes that negate the pandemic as a whole, including the need for COVID-19 vaccination. Fully vaccinated individuals still adhere to the SARS-CoV-2 prevention policies in place.
Membrane Distillation for Wastewater Treatment: A Mini Review
Authors: Yan Zhongsen , Jiang Yuling , Liu Lingshan , Li Zhongsheng , Chen Xiaolei , Xia Mingqian , Fan Gongduan , Ding An
Published: December 2021

Water serves as an indispensable part of human life and production. On account of the overexploitation of traditional water sources, the demand for wastewater recycling is expanding rapidly. As a promising water treatment process, membrane distillation (MD) has been utilized in various wastewater treatments, such as desalination brine, textile wastewater, radioactive wastewater, and oily wastewater. This review summarized the investigation work applying MD in wastewater treatment, and the performance was comprehensively introduced. Moreover, the obstructions of industrialization, such as membrane fouling, membrane wetting, and high energy consumption, were discussed with the practical investigation. To cope with these problems, various strategies have been adopted to enhance MD performance, including coupling membrane processes and developing membranes with specific surface characteristics. In addition, the significance of nutrient recovery and waste heat utilization was indicated.
Impacts of Agricultural Areas on Spatio-Temporal Variability of Daily Minimum Extreme Flows during the Transitional Seasons (Spring and Fall) in Southern Quebec
Authors: Assani Ali Arkamose , Zeroual Ayoub , Roy Alexandre , Kinnard Christophe
Published: December 2021

Several statistical methods were used to analyze the spatio-temporal variability of daily minimum extreme flows (DMEF) in 17 watersheds—divided into three homogenous hydroclimatic regions of southern Quebec—during the transitional seasons (spring and fall), during the 1930–2019 period. Regarding spatial variability, there was a clear difference between the south and north shores of the St. Lawrence River, south of 47° N. DMEF were lower in the more agricultural watersheds on the south shore during transitional seasons compared to those on the north shore. A correlation analysis showed that this difference in flows was mainly due to more agricultural areas ((larger area (>20%) on the south than on the north shore (<5%)). An analysis of the long-term trend of these flows showed that the DMEF of south-shore rivers have increased significantly since the 1960s, during the fall (October to December), due to an increase in rainfall and a reduction in cultivated land, which increased the infiltration in the region. Although there was little difference between the two shores in the spring (April to June), we observed a decrease in minimum extreme flows in half (50%) of the south-shore rivers located north of 47° N.
Development of Boosted Machine Learning Models for Estimating Daily Reference Evapotranspiration and Comparison with Empirical Approaches
Authors: Mehdizadeh Saeid , Mohammadi Babak , Pham Quoc Bao , Duan Zheng
Published: December 2021

Proper irrigation scheduling and agricultural water management require a precise estimation of crop water requirement. In practice, reference evapotranspiration (ETo) is firstly estimated, and used further to calculate the evapotranspiration of each crop. In this study, two new coupled models were developed for estimating daily ETo. Two optimization algorithms, the shuffled frog-leaping algorithm (SFLA) and invasive weed optimization (IWO), were coupled on an adaptive neuro-fuzzy inference system (ANFIS) to develop and implement the two novel hybrid models (ANFIS-SFLA and ANFIS-IWO). Additionally, four empirical models with varying complexities, including Hargreaves–Samani, Romanenko, Priestley–Taylor, and Valiantzas, were used and compared with the developed hybrid models. The performance of all investigated models was evaluated using the ETo estimates with the FAO-56 recommended method as a benchmark, as well as multiple statistical indicators including root-mean-square error (RMSE), relative RMSE (RRMSE), mean absolute error (MAE), coefficient of determination (R2), and Nash–Sutcliffe efficiency (NSE). All models were tested in Tabriz and Shiraz, Iran as the two studied sites. Evaluation results showed that the developed coupled models yielded better results than the classic ANFIS, with the ANFIS-SFLA outperforming the ANFIS-IWO. Among empirical models, generally the Valiantzas model in its original and calibrated versions presented the best performance. In terms of model complexity (the number of predictors), the model performance was obviously enhanced by an increasing number of predictors. The most accurate estimates of the daily ETo for the study sites were achieved via the hybrid ANFIS-SFLA models using full predictors, with RMSE within 0.15 mm day−1, RRMSE within 4%, MAE within 0.11 mm day−1, and both a high R2 and NSE of 0.99 in the test phase at the two studied sites.
Vulnerability and Adaptation to Flood Hazards in Rural Settlements of Limpopo Province, South Africa
Authors: Munyai Rendani B. , Chikoore Hector , Musyoki Agnes , Chakwizira James , Muofhe Tshimbiluni P. , Xulu Nkosinathi G. , Manyanya Tshilidzi C.
Published: December 2021

Climate change has increased the frequency of extreme weather events such as heavy rainfall leading to floods in several regions. In Africa, rural communities are more vulnerable to flooding, particularly those that dwell in low altitude areas or near rivers and those regions affected by tropical storms. This study examined flood vulnerability in three rural villages in South Africa’s northern Limpopo Province and how communities are building resilience and coping with the hazard. These villages lie at the foot of the north-eastern escarpment, and are often exposed to frequent rainfall enhanced by orographic factors. Although extreme rainfall events are rare in the study area, we analyzed daily rainfall and showed how heavy rainfall of short duration can lead to flooding using case studies. Historical floods were also mapped using remote sensing via the topographical approach and two types of flooding were identified, i.e., those due to extreme rainfall and those due to poor drainage or blocked drainage channels. A field survey was also conducted using questionnaires administered to samples of affected households to identify flood vulnerability indicators and adaptation strategies. Key informant interviews were held with disaster management authorities to provide additional information on flood indicators. Subsequently, a flood vulnerability index was computed to measure the extent of flood vulnerability of the selected communities and it was found that all three villages have a ‘vulnerability to floods’ level, considered a medium level vulnerability. The study also details temporary and long-term adaptation strategies/actions employed by respondents and interventions by local authorities to mitigate the impacts of flooding. Adaptation strategies range from digging furrows to divert water and temporary relocations, to constructing a raised patio around the house. Key recommendations include the need for public awareness; implementation of a raft of improvements and a sustainable infrastructure maintenance regime; integration of modern mitigations with local indigenous knowledge; and development of programs to ensure resilience through incorporation of Integrated Development Planning.
Using Freshwater Heads to Analyze Flow Directions in Saline Aquifers of the Pingtung Plain, Taiwan
Authors: Chiu Yung-Chia , Chen Chun-Hung , Cheng Yun-Ta , Chen Wenfu
Published: December 2021

The hydraulic head is the most important parameter for the study of groundwater. However, a head measured from observation wells containing groundwater of variable density should be corrected to a reference density (e.g., a freshwater head). Some previous case studies have used unknown density hydraulic heads for calibrating flow models. Errors arising from the use of observed hydraulic head data of unknown density are, therefore, likely one of the most overlooked issues in flow simulations of seawater intrusion. Here, we present a case study that uses the freshwater head, instead of the observed hydraulic head, to analyze the flow paths of saline groundwater in the coastal region of the Pingtung Plain, Taiwan. Out of a total of 134 observation wells within the Pingtung Plain, 19 wells have been determined to be saline, with Electric Conductivity (EC) values higher than 1500 μS/cm during 2012. The misuse of observed hydraulic heads causes misinterpretation of the flow direction of saline groundwater. For such saline aquifers, the determination of a freshwater head requires density information obtained from an observation well. Instead of the purging and sampling method, we recommend EC logging using a month interval. Our research indicates that EC values within an observation well within saline aquifers vary not only vertically but also by season.
Infiltration under Ponded Conditions
Authors: Argyrokastritis Ioannis , Psychogiou Maria , Londra Paraskevi A.
Published: December 2021

Ponded infiltration processes occur in agricultural lands irrigated by flooding of their soil surface or under insufficient drainage conditions. The existing equations describing the phenomenon of vertical infiltration under ponded conditions have not considered the actual contribution of the pressure head gradient to the flow. In this study, simple equations are proposed to describe the horizontal and vertical infiltration under various ponding heads incorporating the actual contribution of the pressure head gradient to the flow. Six soils with known hydraulic properties, covering a wide range of soil textures, were used. Horizontal and vertical infiltration data are obtained by numerical simulation for all soils studied using the Hydrus-1D code. To validate the accuracy of the proposed equations, the solutions of horizontal and vertical infiltrations provided by the proposed equations were compared with numerically simulated ones provided by the Hydrus 1-D. The analysis of the results showed a very good agreement in all soils studied. The proposed vertical infiltration equation was also compared to a simple and accurate equation which does not incorporate the actual contribution of the pressure head gradient to the flow and differences between them were observed in all soils studied.
Peculiarities of hormonal regulation of the blood antioxidant system of adolescents with obesity
Authors: Davydov V. V. , Babitchev A. V.
Published: December 2021

The study is designed to establish the relationship between the rate of the induced blood lipid peroxidation and production of some hormones in adolescents. The investigations have not shown any significant alteration in the blood insulin content as well as in the daily catecholamines and melatonin excretion in the urine of adolescents in early puberty with the I–II degree of neuroendocrine obesity and without insulin resistance. The rate of the induced blood lipid peroxidation in them remains to be at the initial level. In adolescents of the same age group hyperinsulinemia and an increased urinary excretion of catecholamines and melatonin occur against the background of the concomitant insulin resistance. The rate of the induced blood lipid peroxidation in such cases remains at the level of control values. Formation of hyperinsulinemia and an increased urinary excretion of norepinephrine and melatonin have been registered in late puberty in adolescents with neuroendocrine obesity of the I–II degree without insulin resistance. The emergence of these changes is accompanied by the maintenance of control values of the induced blood lipid peroxidation. The similar changes in the endocrine parameters with attendant increase in the rate of the induced blood lipid peroxidation are occurred in adolescents of the above-mentioned age group with neuroendocrine obesity against the background of insulin resistance.
Features of the development of business models in the sharing economy
Authors: Arkhipova Svetlana Mikhailovna
Published: December 2021

The article is devoted to the study of the features of the development of platforms as business models of the sharing economy. Based on the empirical data of the two platforms Amazon and Airnbnb, a comparative analysis was carried out and recommendations were developed for improving these business models and for their further development. The author identified the features and highlighted the importance of the development of marketplaces in the development of the sharing economy.
Análisis del comportamiento económico financiero de los sectores empresariales de Milagro, Ecuador
Authors: Moreira Macías María Fernanda , Carvajal Salgado Ana , Barreno Salinas María Mercedes
Published: December 2021

El análisis del comportamiento económico-financiero del sector empresarial de Milagro, Ecuador tiene la necesidad de responder ¿Cómo afecta el comportamiento económico-financiero de los sectores empresariales en la población de esta ciudad? En el presente trabajo se estableció como objetivo analizar el comportamiento económico-financiero de los sectores empresariales que tienen acción en este sector; para ello se utilizó como recurso la búsqueda de información mediante el estudio de bases de datos de las empresas más rentables del cantón y cómo estas han logrado diferenciarse de la competencia que proviene de fuera de la ciudad, así como también mediante el SRI se determinó la cantidad de empresas en el cantón y campo de acción y contribución en la economía. Se planteó qué tipos de sectores empresariales intervienen con más fuerza en la economía de Milagro y cómo estos generan rentabilidad que es distribuida por los habitantes del sector.

 

Palabras clave: sector empresarial; sector económico-financiero; rentabilidad.
El impacto económico del turismo en la Provincia de Loja, Ecuador. Evaluación histórica y prospectiva
Authors: Vallejo Ramírez Jorge Baltazar , Malla Alvarado Franklin Yovani , Lalangui Lima Maritza Silvana , Ochoa Herrera Johanna Maribel
Published: December 2021

El objetivo que persigue la investigación tiene relación con el análisis de la relación del turismo y la economía en la provincia de Loja, Ecuador, sitio que cuenta con varias alternativas para el desarrollo de esta actividad económica por su privilegiada ubicación geográfica y calidad humana de su población; el estudio está fundamentado en información del Ministerio de Turismo del Ecuador, razón por la cual son datos objetivos en función a su entorno; en los resultados se destaca la romería de la Virgen del Cisne desde su Basílica hasta la ciudad de Loja o el festival internacional de artes vivas que cada año cobra mayor interés en la comunidad nacional como internacional permitiendo la entrada de divisas a los comerciantes y tributos al Estado, contando con un presupuesto de $ 3.000.000 en anteriores ediciones, dando a entender la importancia que revierte su ejecución.

 

Palabras clave: estudios sectoriales; servicio; economía; recursos; divisas; tributos.
La cadena de valor en el proceso agrícola de maracuyá
Authors: Durán Salazar Galo Mauricio , Alcívar Mayor José Adrián
Published: December 2021

La investigación se realizó en la comuna Julio Moreno ubicada en la provincia de Santa Elena, productora agrícola de maracuyá y vende su cosecha a intermediarios. El objetivo de la investigación fue proponer estrategias para que los agricultores puedan obtener mayores ingresos por sus ventas, para ello, se usó el análisis de la de cadena de valor. Los instrumentos utilizados para la investigación fueron entrevistas a personas de la comuna, lo cual permitió conocer los procesos aplicados para la siembra y cosecha de la fruta, dicha información se usó para estimar los costos y gastos de los procesos y determinar el margen de ganancia promedio que se obtienen por hectárea de siembre de maracuyá. La aplicación de la cadena de valor para la comuna, solo corresponde en este caso al primer eslabón que es la producción, ya que la cosecha no se procesa, se vende internamente en estado natural a intermediarios; por ello, se planteó que ofrecer el producto en otras ciudades, generaría aumento de las ventas, además de fomentar el empleo en el recinto; también la comuna puede formar su propia asociación de productores, lo cual tributariamente le exonera del pago del impuesto a la renta, teniendo que redistribuir las utilidades dentro de la comuna.

 

Palabras clave: economía de la empresa; cadena de valor; agricultores; recurso naturales ; costo-beneficio

 

Abstract

The research was done in the commune Julio Moreno located in the province of Santa Elena, agricultural producer of maracuyá and sells its harvest to middleman. The aim of the research was to propose strategies for farmers to earn higher revenue from their sales, for this purpose, the value chain analysis was used. The tools used for research were interviews with people in the commune, which allowed to know the processes applied for the sowing and harvesting of the fruit, this information was used to estimate the costs and expenses of the processes and determine the average profit margin obtained per hectare of fruit sowing. The application of the value chain for the commune, only corresponds in this case to the first link which is production, because the harvest is not processed, it is sold internally to intermediaries; for this reason, it was proposed that offering the product in other cities would generate increased sales, in addition to promoting employment on the premises; The commune can also form its own producer association, which exonerates them from payment of income tax, having to redistribute profits within the commune.

 

Keywords: business Economics; value chain; farmers; natural resource; cost-benefit.