bluuebunny/crossref_metadata_2025 huggingface dataset:
Excel VBA-Based User Defined Functions for Highly Precise Colebrook’s Pipe Flow Friction Approximations: A Comparative Overview
Authors: Brkić Dejan , Stajić Zoran
Published: April 2021

This review paper gives Excel functions for highly precise Colebrook’s pipe flow friction approximations developed by users. All shown codes are implemented as User Defined Functions – UDFs written in Visual Basic for Applications – VBA, a common programming language for MS Excel spreadsheet solver. Accuracy of the friction factor computed using nine to date the most accurate explicit approximations is compared with the sufficiently accurate solution obtained through an iterative scheme which gives satisfying results after sufficient number of iterations. The codes are given for the presented approximations, for the used iterative scheme and for the Colebrook equation expressed through the Lambert W-function (including its cognate Wright ω-function). The developed code for the principal branch of the Lambert W-function has additional and more general application for solving different problems from variety branches of engineering and physics. The approach from this review paper automates computational processes and speeds up manual tasks.
Dyad Model as a Caring Innovation in High Risk Pregnancy
Authors: Wahyuni Sri , Glorino Rumambo Pandin Moses
Published: April 2021

Background Pregnancy is a process of maturity for women that requires adaptation to the changes in their new roles. Adjustment to a new role is not easy, especially if the pregnancy is accompanied by risks, so it is necessary to get treatment to minimize complications. Dyad models that optimize husband or family support are very important to prevent the risk of complications and adapt mothers to their new roles. The purpose of this study was to determine the effect of the dyad model on high-risk pregnancies. The method used with a literature review is through the collection of articles from Scopus, ebsco, ProQuest and PubMed. The results obtained were articles from Scopus 9, Ebsco 107, PubMed 214 and ProQuest 85 which carried out identification, screening and eligibility for 25 articles. Overall results mention. Journals are categorized into 4 groups, Dyad Model and social support, high-risk pregnancy, maternal role and Self Efficacy. Conclusion, there is an effect of the dyad model on care for high-risk pregnancies.
Sterile Insect Technique: Successful Suppression of Aedes Aegypti Field Population in Cuba
Authors: Gato René , Menéndez Zulema , Prieto Enrique , Argilés Rafael , Rodríguez Misladys , Baldoquín Waldemar , Hernández Yisel , Pérez Dennis , Anaya Jorge , Fuentes Ilario , Lorenzo Claudia , González Keren , Campo Yudaisi , Bouyer Jérémy
Published: April 2021

Dengue virus infections are a serious public health problem worldwide. Aedes aegypti is the primary vector of dengue in Cuba. Since there is no vaccine or specific treatment, the control efforts are directed to reduce mosquito populations. The indiscriminate use of pesticides can lead to increase insecticide resistance as well as adverse effects on human health. The sterile insect technique is a species-specific and environmental friendly method of insect control based on the release of large numbers of sterile males. The success of this technique in sustainable control of agricultural pests has encouraged its evaluation for mosquito control. Here, we describe an open field trial to evaluate the effect of the release of irradiated males on a wild population of Aedes aegypti. The case-control study was performed in a suburb of Havana, and compared the mosquito population before and after the intervention, in both control and treated areas. The wild population was monitored by an ovitrap network, recording frequency and density of eggs as well as their hatch rate. A significant induced sterility was observed in the field population, compared to the control. The ovitrap index and the mean eggs/ trap declined dramatically after an expected lag period of twelve and five weeks, respectively. For the last three weeks, no egg was collected in the treated area, evidencing a significant suppression of the wild population. We conclude that the sterile males released competed successfully, and induced enough sterility to suppress the local Aedes aegypti population.
A Framework for Protecting Pregnant Women in the Era of COVID-19 Pandemic
Authors: Dongarwar Deepa , Ajewole Veronica , Harris Kiydra , Oduguwa Emmanuella , Ofili Theresa , Onyenaka Collins , Arnold Sade , Broussard Jorhn , Ishioye Joan , Marshal Jasmine , Mayoya Jamila , Le Danchau , Fadel Mouch , Olaleye Omonike , Salihu Hamisu
Published: April 2021

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent for the coronavirus disease 2019 (COVID-19) pandemic, highlighted and compounded problems while posing new challenges for the pregnant population. Although individual organizations have provided disparate information, guidance, and updates on managing the pregnant population during the current COVID-19 pandemic, it is important to develop a collective model that highlights all the best practices needed to protect the pregnant population during the pandemic. To establish a standard for ensuring safety during the pandemic, we present a framework that describes best practices for the management of the pregnant population during the ongoing COVID-19pandemic.
 
Copyright © 2021 Dongarwar, et al. Published by Global Health and Education Projects, Inc. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in this journal, is properly cited.
Desenvolvimento de Novo Método para Obtenção de Componente de Disco Artificial para Prótese de Coluna Vertebral
Authors: Vojciechovski Junior Joélcio , Fávero Gabriela , Simões de Lima Diego Rodolfo
Published: April 2021

Dores na coluna lombar são as reclamações mais comuns em ortopedia, apresentando prevalência anual de 38% em todo o mundo. Dentre suas causas, destacam-se doenças ou traumas sobre os discos intervertebrais, como síndrome facetaria, hérnias de discos, espondilose e síndrome do disco degenerativo. Um dos possíveis tratamentos para esta enfermidade é a alocação cirúrgica de um disco artificial, composto por duas placas de metais biocompatíveis e um núcleo esponjoso. O uso de metal biocompatível diminui os riscos de rejeição pelo corpo humano, sendo a liga de Titânio Ti-6Al-4V um dos biomateriais mais utilizados neste tipo de aplicação. Ligas de titânio, contudo, possuem características de transformação mecânica peculiares, como alta resistência ao escoamento, à abrasão, e dureza elevada, tornando seus processos de fabricação mais complexos, desgastando ferramentas de usinagem rapidamente, tornando a remoção de material mais dispendiosa. Estudos sobre forjabilidade destas ligas configuram-se em área de interesse da engenharia. Assim, visando à diminuição nos custos de ferramental e aumento da produtividade, o presente estudo se propôs a avaliar a viabilidade do forjamento a quente da liga de titânio Ti-6Al-4V para produção de próteses de disco intervertebral. Escolheu-se uma das placas do disco intervertebral, sendo modelada em software de CAD, projetando-se e usinando-se matrizes para forjamento a quente voltadas a este processo, sendo beneficiadas com tratamento térmico de têmpera e revenimento. Resistências elétricas foram dimensionadas teoricamente e alocadas nas ferramentas para o aquecimento das matrizes. As próximas etapas serão os forjamentos planejados e as caracterizações mecânicas e metalúrgicas das peças obtidas.
Application of LC-MS and Methyl Orange Methods for Improved Residual Surfactant Detection in Liquids-Rich Shale Plays
Authors: He Kai , Heckel John , De Hernandez Vittoria Balsamo , Nguyen Duy
Published: April 2021

Successful field trials of surfactant-based Production Enhancement (PROE) technology in different shale plays including Permian Basin, Bakken and Eagle Ford indicate that specially tailored surfactant formulations can improve the unconventional well productivity during flowback and production. One major challenge for the operator is to further optimize the surfactant dosage to maximize the economic return. Analysis of the residual surfactant concentration in the produced water (PW) might provide a new path to optimize the surfactant application in the field. Such quantitative measurements can help understand how much surfactant is consumed in the downhole and how much surfactant is in the flowback, and possibly correlate back to the well performance. Additionally, surfactant partitioning and adsorption behaviors can be studied through residual analysis, which will further provide guidance to develop next generation of surfactant formulations.

In this study, a liquid chromatography-mass spectrometry (LC-MS) method was developed to accurately measure the residual surfactant concentration in the produced water. The liquid chromatograph (LC) separates the surfactant from sample matrix and avoids the possible interference, and then the mass spectrometer (MS) detects the separated surfactant, signal correlating to the residual concentration. This analytical method provides unrivalled selectivity and specificity compared to other methods reported in the literature. In addition, a Methyl Orange method was developed and can potentially be used in the field for quicker measurements. Produced water samples collected from a Huff-and-Puff treatment in the Permian Basin were evaluated using both methods. Our results indicate that both methods can successfully capture the trend of residual concentration vs. production time. The deviation between LC-MS and Methyl Orange measurements was due to the presence of ADBAC (alkyldimethylbenzylammonium chloride) in the produced water, which is a cationic amine surfactant typically used as biocide in the well stimulation. It produces positive interference and thus leads to a higher residual detection in the Methyl Orange test. Notably, the residual concentration of surfactant in produced water decreased with time after the well was placed back to production, which is consistent with the concept that more surfactant will adsorb to the rock surface or partition into the oil phase over production time.

In summary, we believe the LC-MS and Methyl Orange methods can potentially be used to detect residual concentration for any type of surfactant-based applications in unconventional reservoirs including Huff-and-Puff, completion, frac protect, surfactant flooding and re-frac. The field application of surfactant-based chemistry followed by this type of residual analysis can help understand the underlying mechanisms of the surfactant and provide further guidance for production optimization of shales.
Comprehensive Analysis of Water Cut Metering Accuracies
Authors: Castrup Suzanne
Published: April 2021

Accurate oil production monitoring is essential for scheduling well work and optimizing the economic performance of primary and enhanced recovery projects. The significance of water cut monitoring accuracy on oil rate determination is discussed and illustrated. This paper provides a comprehensive uncertainty analysis of several water cut monitoring methods commonly employed by oil field operators. These include liquid sampling, capacitance, microwave, ultrasonic, spectroscopy and density methods.

The basic operating principles of each monitoring method are described and measurement uncertainty analysis procedures are employed to identify key parameters that affect the overall accuracy of each water cut monitoring method. The analysis results provide useful accuracy assessments that can be used in water cut meter selection, field testing and implementation.
A Practical Gas Apparent Permeability Model: Multi-Scale Simulations of Rarefied Gas Flow in Matrix
Authors: Chai Di , Li Xiaoli
Published: April 2021

A common practice in gas-shale reservoir simulation, which arbitrarily increases intrinsic matrix permeability to match the production data, has been proven inefficient and unreliable. Alternatively, accurate estimations of gas apparent permeability (AP) in matrix is desired. This work presents an analytical AP model considering rarefaction in nanopores and coupling experimentally confirmed mechanisms in shale matrix for theoretical completeness. Meanwhile, physical terms in AP model are simplified with semi-empirical correlations for the practicability in large-scale field simulation. Compared with other gas transport models in nanopores, the newly-developed analytical model has been successfully validated against molecular dynamic (MD) simulation, direct simulation Monte Carlo (DSMC), Lattice Boltzmann (LB) simulation, and experimental flux results for five types of gases (i.e., methane, nitrogen, helium, argon, and oxygen) with the minimum deviation. It is observed that analytical models excluding Knudsen diffusion mechanism cannot fully characterize rarefaction effect. Next, Knudsen diffusion cannot be explained as the only underlying mechanism of rarefaction because the mass flux is largely underestimated in transition flow regime. However, the weighted superposition of second-order slip boundary and Knudsen diffusion can provide the satisfactory fitting with data. This work provides an analytical model which not only considers non-negligible multi-physics in shale reservoirs (i.e., rarefaction effect, multilayer adsorption, surface diffusion and confinement effect) but also simplifies non-linear physical terms using semi-empirical linear correlations to facilitate AP calculations in core-scale simulations.
Hybrid Sand Control Screen Using the Combined Surface and Depth Filtration
Authors: Hosseini Seyed Abolhassan , Roostaei Morteza , Mohammadtabar Farshad , Mohammadtabar Mohammad , Soroush Mohammad , Berner Kelly , Mahmoudi Mahdi , Miller Roger , Fattahpour Vahidoddin
Published: April 2021

Development of weakly and unconsolidated sand reservoirs require effective sand control media to prevent sand production. The existing sand control devices in the market are either relying on surface filtration to prevent sand production through size exclusion or bridging or depth filtration which relies on the pore size distribution of a porous filter or pack to prevent the sand from producing along the production fluids. In this study, we introduce a new hybrid sand screen that works based on a combined surface and depth filtration.

Radial Sand Control Evaluation (RSCE) testing facility was used to compare the solid production and flow performance of the new hybrid screen with various mesh media in multi-phase gas and liquid flow under various fluid injection scenarios. Solid production and flow performance were compared with investigated cases.

The new hybrid screen provides an optimized Open to Flow Area (OFA) in comparison to available surface filtration or depth filtration media, which provides required OFA, while prevents sanding. The robust design, low cost and manufacturing ease make it a suitable screen media for most sand control applications. The sand retention test results under various fluid injection scenarios including multi-phase oil, brine, and gas show that it outperforms the Dutch Twill (DT) weave and Reverse Dutch Twill (RDT) weave of equivalent aperture size, with better flow performance at constant flow rate tests compare to best-performing mesh media, while keeping the produced sand far below the acceptable thresholds. Hybrid design handles both high velocity and high Gas-Oil Ratio (GOR) better than equivalent depth filtration media of equivalent size.

This paper presents a detailed characterization, flow performance testing of a new hybrid sand control media that combines the surface filtration and depth filtration properties to achieve better solid retention and flow performance. The hybrid screen media is suitable for high-rate producers with high GOR.

Keywords: Hybrid Screen, Surface Filtration, Depth Filtration, Radial Sand Control Evaluation (RSCE) Testing
Application of Slurry Injection Technology in Biowaste Management - A New Discipline in Managing Bio-Waste in Economic and Environmentally Friendly Manner
Authors: Panchal Yashesh , Mounir Nihal , Loloi Mehdi , Mohamed Ibrahim , Abou-Sayed Omar , Abou-Sayed Ahmed
Published: April 2021

Carbon offset describes the environmental benefit from an initiative that avoids, reduces or removes greenhouse gases (GHGs) from the atmosphere. The Intergovernmental Panel on Climate Change has identified Carbon Dioxide (CO2), Methane (CH4) and Nitrous Oxide (N2O) as major constituent of the GHGs. Wastewater Treatment Facilities (WWTFs) among several other sectors is a neglected source for GHG emission. Considering the risk of rise in GHGs, United States along with other countries signed the Paris Agreement to respond to the global climate change threat in 2016. It is assessing projects to cut GHGs in exchange for emission credits that can be used to comply with goals they set under the United Nations pact.

In order to curb the GHG emission by WWTFs, an innovative approach "Bioslurry Injection" (BSI) can be implemented to reduce the emission of the GHGs produced during the course of biological and chemical treatment of wastewater. The technology is inherited from the traditional drill cutting injection and Carbon sequestration technology implemented by the Oil and Gas industry since 1980's. The BSI operation has the ability to accept the feed from different treatment stages after the initial screening process to prepare the injection slurry and help in controlling the GHG emission at respective treatment stage along with managing the intake volume.

The slurry can be prepared by mixing the treated biosolids with wastewater and injected into a pre-selected underground earth formation, where biosolids undergo anaerobic digestion and decompose into CO2 and CH4. An injection formation with sufficient capacity to accept the slurry is selected by conducting a detailed geomechanical and fracture simulation analyses. Along with the injection feasibility, the calculations of the amount of Carbon dioxide equivalent (CO2e) sequestrated underground by implementing BSI technique is presented in this paper.

The sequestration of decomposed GHGs is an environmentally friendly activity that has proved to be economically beneficial due to its ability to earn carbon offsets. According to the new carbon law in the state of California the amount of CO2e eliminated from the atmosphere can be traded to earn carbon credits. TIRE facility through its ability to sequester and thus eliminate emission of the GHGs from the atmosphere can gain up to $1.5M worth of carbon credits per year providing both environmental and economic benefit. Also, low capital and operating cost for the BSI facility due to its compact surface requirement is an additional advantage along with reduced risk of spillage hazard when BSI facility is incorporated within the WWTF boundaries.
Ignition Forecast Based on Chemical Kinetics and Uncertainty Quantification
Authors: Li Yunan , Anderson Timothy I. , Kovscek Anthony R.
Published: April 2021

The description of chemical kinetics is very import to the simulation of reactive transport for enhanced oil recovery (EOR). Characterizing petroleum ignition is especially important for simulation and prediction of In-Situ Combustion (ISC). In order to model crude oil oxidation reactions accurately, an experimental workflow is introduced to obtain kinetic parameters for ISC chemical reaction models. An optimization algorithm assists to match the reaction model parameters to the experimental results, and this validated model is used to predict ignition of crude oil in porous media. Apparent activation energy is estimated from ramped temperature oxidation experiments under several heating rates, including 1.5, 2.0, 2.5, 3.0, 5, 10, 15, and 20 °C/min. These experiments are separated into a small heating rates group (1.5, 2.0, 2.5, 3.0 °/min) and large heating rates (5, 10, 15, 20 °/min). The results show that experiments with small heating rates capture the details of reaction kinetics such that the estimated activation energy is more accurate, with the validated simulation model able to make accurate predictions for this particular crude oil. After matching the kinetics parameters, we predict the ignition conditions as a function of the air flow rates and the heat loss rates. The ignition envelope indicates that the window for air flow rates to ignite the oil decreases if the heat loss rate is high. Greater heat losses require more thermal energy to be released from the reaction to overcome losses and for ignition to occur. This leads to a narrower range of ignition air flow rates due to convective heat transfer. The uncertainty quantification results provide a confidence region for the ignition envelope impacted by the threshold temperature of the ignition criterion. The novelty of this work is the description of optimized combustion reaction models with rigorous experimental verification and uncertainty quantification for reactive transport simulations.
Fast Drilling Optimizer for Drilling Automation
Authors: Giftson Joy John Abish , Samuel Robello
Published: April 2021

The rate of penetration (ROP) was optimized using a particle swarm optimization algorithm for real-time field data to reduce drilling time and increase efficiency. ROP is directly related to drilling costs and is a major factor in determining mechanical specific energy, which is often used to quantify drilling efficiency. Optimization of ROP can therefore help cut down costs associated with drilling. ROP values were chosen from real-time field data, accounting for weight on bit, bit rotation, flow rate variation along with bit wear. A random forest regressor was used to find correlations between the dependent parameters. The parameters were then optimized for the given constraints to find the optimal solution space. The boundary constraints for the ROP function were determined from the real-time data. The function parameters were optimized using a particle swarm optimization algorithm. This is a meta-heuristic model used to optimize an objective function for its maximum or minimum within given constraints. The optimization method makes use of a population of solution particles which act as the particle swarm. These particles move collectively in the given solution space controlled by a mathematical model based on their position and velocity. This model makes use of the best-known solution for each particle and the global best position of the system to guide the swarm towards the optimal solution. The function was optimized for each well, providing optimal ROP values during real-time drilling. A fast drilling optimizer is crucial to automate and streamline the drilling process. This simultaneous optimization of ROP based on real-time data can be implemented during the process thereby increasing the efficiency of drilling as well as reducing the required drilling time.
NORM Scale Removal Using a High-Power Fiber Laser Beam Delivery
Authors: Lewis Janelle Branch , Dassey Adam , Grubb Daryl , Marshall Scott
Published: April 2021

In oil and gas operations, there is a potential for NORM scale to accumulate on process piping and equipment. This scale can be removed prior to recycling or disposal of the material, yet common removal methods may be costly, time consuming, or create large volumes of secondary waste streams that must be managed. The feasibility of using a laser beam delivery to remove NORM scale was investigated because of its potential to reduce the time and cost associated with scale removal without creating large secondary waste streams. Results from this study indicate that a laser beam delivery could be an effective method to remove NORM scale from a steel surface. Background levels of alpha and beta surface contamination and gamma exposure rate were achieved for certain pipe sections when applying a laser power of at least 5 kW. Alternative laser powers, linear speeds, or incident angles may optimize the removal efficiency for thicker scales or scales with higher surface contamination or gamma exposure rates.
A 17 Year Successional Enrichment Plantation of Tree Recruitment and Restoration in an African Tropical Forest
Authors: Omomoh Bernard Eromosele , Akomolafe Gbenga Festus , Brown Leah Spencer , Adekunle VAJ
Published: April 2021

Key message: The Enrichment Plantation of Akure Forest Reserve is one of the forests currently experiencing a 17-year-long post-disturbance following deforestation and fragmentation in Nigeria. Context: To better understand the contribution of enrichment planting on forest regeneration and restoration, when the Enrichment Plantation after 17 years of post-disturbance was examined. Aims: We studied the recruitment drive of aboveground and undergrowth stands of an Enrichment Plantation in the tropical forest reserve. We assess the trees diversity, species compositions, species richness, and growth forms of the vegetations. Methods: A total of 3(50m x50m) plots were sampled. A total of 47 aboveground tree species and 45 undergrowth stands from Enrichment Plantation were identified. A statistical analysis were used to quantified the data obtained from this resultsResults: The result shows an increase in the diversity and an even distribution of the species of the aboveground forest trees, compared to the undergrowth stands. Conversely, the aboveground forest trees have lower species richness as compared to the level of undergrowth stands. The sapling density was significantly higher than the aboveground tree of the. It was also observed that the aboveground forest trees and undergrowth stands are somewhat similar in species compositions, which implies that sapling recruitment is a key determinant of the tree species composition of the forest.Conclusion: It is then concluded that the method adopted for restoration encouraged species diversity in this successional forest among the aboveground trees species and undergrowth.
DBA_SSD ： A Novel End-to-End Object Detection Using Deep Attention Module for Helping Smart Device with Vegetable and Fruit Leaf Plant Disease Detection
Authors: Wang Jun , Yang Jing , Yu Liya , Dong Hao , Yun Kun , Wang Yifan
Published: April 2021

In response to the difficulty of detecting and classifying pests and vegetable and fruit leaves with pests and diseases, this study proposes a novel vegetable and fruit leaf pest detection method called deep block attention SSD (DBA_SSD) for the identification of pests and diseases and classification of the degree of pests and diseases of vegetable and fruit leaves. We propose three vegetable and fruit leaf pest detection methods, namely, squeeze-and excitation SSD (Se_SSD), DB_SSD, and DBA_SSD. Se_SSD fuses SSD feature extraction network and attention mechanism channel, DB_SSD improves VGG feature extraction network, and DBA_SSD fuses the improved VGG network and channel attention mechanism. To reduce the training time and accelerate the training process, the convolutional layers trained in the Image Net image dataset by the VGG model are migrated to this model, whereas the collected vegetable and fruit disease image dataset is randomly divided into training set, validation set, and test set in the ratio of 8:1:1. In addition, data enhancement methods, such as histogram equalization and horizontal flip were used to expand the image data. The performance of the three improved algorithms is compared and analyzed in the same environment and with the classical target detection algorithms YOLOv4, YOLOv3, Faster RCNN, and YOLOv4 tiny. Experiments show that DBA_SSD outperforms the two other improved algorithms, and its performance in comparative analysis is superior to other target detection algorithms.
Construction and Transmission Mechanism of Exterior Ballistics of High-Power Microwave Weapons
Authors: Hao Lingjun , Xiao Yujie , Xie Jun , He Yi , Wang Liang , Chen Yi , Cao Xin , Sun Hai-wen
Published: April 2021

Booming technological advances and turbulent military reforms have promoted the continuous advancement of weapons and equipment. High-power microwave (HPM) weapons have changed the damage modes of traditional guns, missiles and other kinetic energy weapons, as well as having the huge advantage of "changing the rules of the game." The study of exterior ballistics of high-power microwave weapons has theoretical support for the design and development of weapons and the verification of performance indicators, and is also an important basis in the firing application of high-power microwave weapons. By studying the coupling mechanism between HPM weapons and targets, an exterior ballistics description of HPM weapons is given According to the description of exterior ballistics, the differences between HPM and traditional weapons in definitions, accuracies, space trajectories, space descriptions and "end points" are summarized and the exterior ballistics space transmission is established. This study reveals the nine major transmission laws of the exterior ballistics of HPM weapons. The constructed model and related theories of the transmission laws for exterior ballistics lay a theoretical foundation for the in-depth study of key technologies of HPM weapons, such as fire control and damage assessment.
An efficient prediction model of effective thermal conductivity for metal powder bed in additive manufacturing
Authors: Zhao Yizhen , Zhang Hang , Cai Jianglong , Ji Shaokun , Li Dichen
Published: April 2021

The particle accumulation structure is commonly found in diverse engineering fields, including additive manufacturing powder, powder metallurgy, advanced reactor, grain storage and catalyst bed. The relative thermal conductivity of such structure is an important parameter to study the heat transfer behavior of the accumulation. In the study, the key factors affecting on the thermal conductivity of the powder is analyzed. Based on the results, the expression for calculating the thermal conductivity of the sphere metal powder is successfully reduced to only one parameter d50 and an efficient calculation model is proposed which can applicate both in room and high temperature. Meanwhile, the corresponding error is less than 20.9% in room temperature and 50% in high temperature.
Estimation and optimal control of the multi-scale dynamics of the Covid-19
Authors: MBOGNE David Jaurès FOTSA , TCHOUMI Stéphane Yanick , TCHAPTCHIE Yannick KOUAKEP , KAMLA Vivient Corneille , KAMGANG Jean Claude , DANGA Duplex Elvis HOUPA , TSAKOU Samuel BOWONG , BEKOLLE David
Published: April 2021

This work aims at a better understanding and the optimal control of the spread of the new severe acute respiratory corona virus 2 (SARS-CoV-2). We first propose a multi-scale model giving insights on the virus population dynamics, the transmission process and the infection mechanism. We consider 10 compartments in the human population in order to take into accounts the effects of different specific mitigation policies. The population of viruses is also partitioned into 10 compartments corresponding respectively to each of the first nine human population compartments and the free viruses available in the environment. We show the global stability of the disease free equilibrium if a given threshold T_0 is less or equal to 1 and we provide how to compute the basic reproduction number R_0. A convergence index T_1 is also defined in order to estimate the speed at which the disease extincts and an upper bound to the time of extinction is given. The existence of the endemic equilibrium is conditional and its description is provided. We evaluate the sensitivity of R_0, T_0 and T_1 to control parameters such as the maximal human density allowed per unit of surface, the rate of disinfection both for people and environment, the mobility probability, the wearing mask probability or efficiency, and the human to human contact rate which results from the previous one. Except the maximal human density allowed per unit of surface, all those parameters have significant effects on the qualitative dynamics of the disease. The most significant is the probability of wearing mask followed by the probability of mobility and the disinfection rate. According to a functional cost taking into consideration economic impacts of SARS-CoV-2, we determine and discuss optimal fighting strategies. The study is applied to real available data from Cameroon and an estimation of model parameters is done. After several simulations, social distancing and the disinfection frequency appear as the main elements of the optimal control strategy.
Selenium-containing compound ameliorates lipopolysaccharide-induced acute lung injury via regulating MAPKs/AP-1 pathway
Authors: Jia Wenjing , Ding Wenting , Chen Xinmiao , Xu Zhengwei , Tang Yeilin , Wang Meihong , Zheng Bin , Zhang Yali , Wei Tao , Zhu Zaisheng
Published: April 2021

Acute lung injury (ALI) characterized by a series of inflammatory reactions and served as the main cause of mortality in intensive care unit patients. Although great progress have been made in understanding the pathophysiology of ALI, there are no effective treatment in clinic. Recently, we have synthesized a selenium-containing compounds, which possess obvious anti-inflammatory activity. The aim of the present study is to evaluate the protective effects of the selenium-containing compound 34# in LPS-induced ALI in mice as well as its underlying mechanism. Compound 34# was found to inhibit LPS-induced macrophage inflammatory cytokine release. These effects were observed to be produced via suppression of the MAPKs/AP-1 pathway. Compound 34# was also noted to attenuate the LPS-induced lung inflammation in mice with ALI. The corresponding results suggested that compound 34# possesses remarkable protective effects on LPS-induced ALI. Furthermore, the MAPKs/AP-1 pathway may prove to be its the underlying mechanism. Accordingly, compound 34# may serve as a potential candidate for the prevention of ALI.
Bilateral Control of a 2-DOF Teleoperated Manipulator Using UDP Scheme
Authors: Mohsen Magdi , Ibrahim khalil
Published: April 2021

In this paper, a workspace-control system was developed to deals with the problem of position-tracking of bilateral teleoperated two degrees of freedom manipulators, and aid the human operator in driving and controlling the slave robot that performs critical and difficult tasks such as under water works. The developed system consists of, "JUPITER XL SCARA" robot as a slave manipulator with only the first two links activated, a wireless User Datagram Protocol (UDP) network, and PC as a master controller. The system model parameters identified using the Least-Squares method. A PID and FLC controllers with different input signals were applied to the system. It was proved experimentally and by simulation on Matlab that the FLC gave a better performance than the PID controller. The two parallel loop subroutine technique proved a great enhancement to the system performance as it decreased the total delay time in the system to almost 25 milliseconds.
In Vitro Responses of Alfalfa Root (Medicago Sativa L.) to Salt stress and Melatonin
Authors: Jalili Shabnam , Ehsanpour Ali Akbar
Published: April 2021

Alfalfa (Medicago sativa L.) is the most cultivated forage legume. The growth and development of alfalfa roots are limited by salt stress. Growth regulator is an essential role of melatonin in plants, especially in root involved in stress tolerance. In this study, alfalfa roots under in vitro salt stress (150 and 200 mM NaCl) were pretreated with different concentrations of melatonin (0.1, 10 and 15 μM). principal component analysis to find out the best targets for melatonin and salinity. Exogenous utilization of melatonin in alfalfa roots significantly elevated the compatible solutes particularly glycin betaein (GB), soluble carbohydrate and K+ content. Principal component analysis revealed that, Indol acetic acid (IAA) content, GB, flavonoids, carbohydrate and Na+ were the best melatonin targets. Furthermore, salinity affected ROS, H2O2, O2-, malondialdehyde (MDA), phenylalanine ammonia-lyase (PAL), K+/Na+ ratio and tyrosine ammonia-lyase (TAL) enzymes were augmented, and electrolyte leakage, Na+ accumulation decreased in the saline medium.
Effect of 4-h time restricted feeding on body weight, leptin concentration and lipid profile in healthy non-obese male Wistar rats
Authors: Olamoyegun Michael A. , Ajao Folasade O. , Iyedupe Marcus O.
Published: April 2021

Background: Obesity greatly increases the risk of metabolic diseases and preventive approaches for obesity are often inadequate to effectively prevent and manage the diseases. Altering feeding time strategy intervention decreases caloric intake without calorie counting and may be an effective therapy. Therefore, this study investigates the effect of 4-h time restricted feeding on body weight, leptin concentration and lipid profile in healthy non-obese male Wistar rats. Methods: Rats placed on time-restricted feeding (TRF) regimen had freely access to food for 4 hour per day at designated periods. Twenty four rats divided into four groups (n=6) were used. Group I animals were placed on a 4 hour per day TRF between 8am-12noon. Group II rats were also placed on a 4 hour per day TRF between 12noon-4pm. Group III rats also placed on a 4 hour per day TRF between 8pm-12 midnight while Group IV rats had access food and water ad libitum. This diet strategy resembles taking only breakfast, lunch or dinner once a day. The study lasted for a period of 4 weeks with daily food intake and weekly body weight determined throughout the period. At the end of the experimental period, blood glucose, lipid profile and leptin concentration were assessed. SPSS 21.0 package was used for data analysis, one-way analysis of variance (ANOVA) was used to compare the mean values of variables among the groups and bonferroni’s posthoc test was used for significance of pair wise comparisons of mean values among the groups. Significance was set at p < 0.05.Results: In this study, the body weights and leptin concentrations of 8pm – 12am and ad libitum groups significantly increased compared with the 8am - 12noon and 12noon -4pm groups. Dyslipidemia was observed in the ad libitum group when compared with the 8am - 12noon and 12noon - 4pm groups. Conclusion: From this study, 4-hr time restricted feeding has beneficial effects on body weight, blood glucose, lipid profile and leptin concentration. This feeding restriction patterns may be helpful in obesity management and in preventing metabolic diseases development in non obese.
Application of stress susceptibility index and multivariate analysis of tomato (Solanum lycopersicum L.) to identify thermo-tolerant genotypes
Authors: A. Archana K. , Pradeepkumar T. , Gopinath Pratheesh P , V. Santhoshkumar A.
Published: April 2021

Climatic parameters have become key mechanisms in controlling crop productivity worldwide. The more frequency of heat waves urges the breeding for thermo-tolerance. The motive of this study was to furnish an accurate and deep understanding on the heat tolerance of reproductive key traits (flowers with exerted stigma, pollen viability, fruits set per cent and number of fruits per cluster), along with earliness (days to first fruit set) and yield traits (average fruit weight, pericarp thickness, number of fruits per plant and yield per plant) in tomato. The study reasoned 35 genotypes employing three no-identical analysis tools, ANOVA of field assessment, stress susceptibility index and multivariate analysis based on genetic diversity. Insights of genetic architecture of the reproductive traits under heat stress might improve our core understanding, and might have applied value. The study substantiated the essence of heat tolerance for the genotypes EC-620395, EC-620401, EC-620406 and EC-620410. Divergence analysis revealed five clusters corresponding to specific characters. Therefore on the ground of the investigation new breeding lines and breeding strategies can be implemented under changing environmental conditions with special reference to elevated temperature.
On-Farm Diversity of Common Bean (Phaseolus Vulgaris L.) Varieties in East Hararghe Zone, Eastern Ethiopia
Authors: Sahle Sate , Tana Tamado , Dechassa Nigussie , Zeleke Habtamu
Published: April 2021

Common bean (Phaseolus vulgaris L.) is an important source of food and income. However, its on-farm diversity and conservation by smallholder farmers is not known in the east Hararghe Zone of eastern Ethiopia. Thus, field survey was conducted from November 2018 to February 2019 to assess the on-farm diversity, cropping system and the role of gender in production and management of common bean varieties. Common bean producing districts were selected purposively whereas sub-districts (kebeles) were selected randomly. Three kebeles from each of the two major agro-ecological zones, two key informants and twelve general informants from each kebele were selected to constitute a total of 84 informants. The selection of general informants was stratified based on gender and wealth status. Structured interview guide was used to interview general informants whereas semi-structured interview guide was used to interview key informants. Descriptive and inferential statistical analyses were conducted in R (version 3.5.2). Seven farmers’ varieties of common bean were identified of and their diversity was higher in tepid, moist mid highlands (M3) whereas cropped area (ha) was significantly (p < 0.05) higher in tepid sub-humid highlands (SH3) agro-ecology. Most activities of common bean were undertaken by male adults. Insect pests were the prominent constraints of common bean production. Farmers’ varieties were used as food and feed, and soil fertility management. Therefore, their on-farm and ex situ conservation, maintenance of endangered varieties, and shortage of cropping land due to chat plantation need special concern to promote their cultivation.
Efficient toluene adsorption/desorption on biochar derived from in situ acid-treated sugarcane bagasse
Authors: Qu Yuan , Xu Li , Chen Yi , Sun Shikuan , Wang Yu , Guo Li Min
Published: April 2021

Carbon-based materials with great adsorption performance are of importance to meet the needs of industrial gas adsorption. Being massive agricultural wastes of sugarcane bagasse, China could use this waste into wealth. However, the comprehensive utilization of sugarcane bagasse as precursors for biochar that can be used as adsorbent has not been extensively explored. In this study, a series of in-situ sulfuric acid modified biochar were prepared by hydrothermal carbonization process. The prepared biochar (SBAC-7) is combined of two main advantages that are high microporosity (micropore surface area = 1106 m 2 /g) and rich in S-containing functional groups on the surface. In particular, SBAC-7 showed an excellent adsorption capacity of toluene (771.1 mg/g) at 30 o C, which is nearly 3 times as high as the commercial activated carbons. Meanwhile, it showed great stability and cyclic regeneration performance with five toluene adsorption-desorption test cycles. This study provides a high-performance biochar for adsorption-desorption cycle in practical engineering applications, and would contribute to the sustainable “sugarcane production - bagasse utilization” circular economy.
User experiences and perceptions of health wearables: a cross-sectional study in Cambodia
Authors: Liverani Marco , Ir Por , Wiseman Virginia , Perel Pablo
Published: April 2021

Background: In many low- and middle-income countries (LMICs), health system capacities to address the burden of non-communicable diseases (NCDs) are often inadequate. In these countries, wearable health technologies such as smartbands and smartwatches could be used as part of public health programmes to improve the monitoring, prevention, and control of NCDs. Considering this potential, a study was conducted in Cambodia to explore user experiences and perceptions of a watch-type health wearable, including utilisation patterns, perceived usefulness and usability, and willingness to pay. Methods: Data collection involved a baseline survey, conducted in 2019 with different categories of participants (including hypertensive participants, non-hypertensive participants, postgraduate students, and civil servants), and a follow-up survey with the same participants, one month after they were given a sample of the wearable and advised to wear it day and night. ﻿Results were analysed using descriptive statistics, test statistics, and binomial regression to predict the utilisation of the paired smartphone application. Results: A total of 156 adult participants completed the baseline and follow-up surveys. The reception of the technology was positive overall: 89.1% of the participants said they would continue using the watch and 76.9% of them would recommend it to either friends or relatives, while 94% said the device stimulated them to think more frequently about their health\. However, challenges to technology acceptance were identified, including concerns with the accuracy and quality of the device and unfamiliarity with the concept of health self-monitoring, especially among the elderly. Short battery life and cost were also identified as potential barriers to continued use. Conclusions: Health wearables are a promising new technology that could be used in Cambodia and in other LMICs to strengthen health sector responses to the challenges of NCDs. However, this technology should be carefully adapted to the local context and the needs of less resourced population groups. In addition, further research should investigate if adequate health sector support and infrastructure are in place to implement and sustain the technology.
The Commonest Indications of Cesarean Sections at Ghalib Teaching Hospital in Year 2017; Cross-sectional Study
Authors: Fazli Mohammad Rafi , Mansouri Amena , Wahidi Hania
Published: April 2021

Background: In the past few decades, the rate of cesarean section (CS) has increased worldwide which is common in high income countries. Although cesarean section has lots of socioeconomic impacts in the career of mothers and babies especially in LMICs like Afghanistan, it is also increasing in such countries. In compare to vaginal delivery the cesarean section has higher risks for maternal health. The most important aim of this study is to search the commonest indications of cesarean section at the only teaching hospital in west region of Afghanistan, Ghalib Teaching Hospital in 2017.Material and Method: This was a cross-sectional study. Among 456 pregnant women who came to Ghalib Teaching Hospital, 287(63%) had vaginal delivery and 169 (37%) had cesarean section delivery in 2017. Data was collected reviewing medical records; patients discharge certificate and a questionnaire which consisted of the data like; history of previous cesarean sections, age, and so on. Data was analyzed by epi info 7.Results: the prevalence of cesarean section in Ghalib Teaching Hospital was 37%, the median age was 28 years old, the mean age was 23.83 and the most ages were between 21-25 (42.5%). The commonest indications were severe oligohydramnios (29.5%) followed by previous cesarean section (12.4%) and elective cesarean section 10.9% (on maternal request). The least indication was cephalopelvic disproportion (3.09%). In our research we had more than one indication about 10.3%.Conclusion: according to the research the commonest indication of cesarean section was severe oligohydromnios which shows emergency indication among pregnant women. As the women in Afghanistan want many children so they usually do not consider having cesarean section deliveries. Cesarean section on maternal request also has high rate which needs appropriate guidelines and also policies to decrease this high rate of selective cesarean section. In our research 52.1% of indications of CS was fetal factors. This shows in LMICs many fathers have valued to the health of babies instead of mothers. It is highly needed to inform fathers to know about health of both babies and mothers.