bluuebunny/crossref_metadata_2025 huggingface dataset:
Fire safety of hydrogen filling stations
Authors: Shebeko Yu. N.
Published: July 2021

Introduction. The problem of greenhouse gas emissions from hydrocarbon-powered vehicles, polluting the air, makes consumption of hydrogen as an alternative motor fuel particularly relevant. Solutions to this problem are provided in a number of works written by foreign researchers. This article contains the analysis of these works in respect of fi re and explosion safety assurance at gaseous and liquid hydrogen filling stations (hydrogen fi lling stations).

Features of hydrogen storage. Motor fuel storage is a main problem of hydrogen filling stations and their operation. Most advanced hydrogen storage methods (applicable to gaseous, liquid and adsorbed hydrogen, as well as metal hydrides that contain hydrogen) are analyzed in the work.

Compressed hydrogen filling stations. Fire and explosion safety features of filling stations, where compressed hydrogen is stored, are considered by the author. As a rule, mobile fuel trucks, equipped with compressed gas tanks, are used there.

Liquid hydrogen filling stations. Fire safety aspects of filling stations, where liquid hydrogen is stored, regasifi cation is performed, and vehicles are fi lled with compressed gas, are also analyzed.

Hydrogen formation at filling stations. One of the ways to supply fuel to a hydrogen filling station is to produce it on site using dehydrogenation of methylcyclohexane, which is delivered in tank trucks. Hydrogen is compressed and stored in cylinders. Fire hazards arising at such stations are analyzed.

Main provisions of NFPA 2 in terms of hydrogen filling stations. The requirements of the international standard NFPA 2 Hydrogen Technologies Code. 2016 Edition, that apply to compressed and liquefi ed hydrogen filling stations, are considered.

Conclusions. The author has made a conclusion that hydrogen fi lling stations are intensively built in several countries. It has been proven that if necessary protective measures are taken, hydrogen fi lling stations can be as safe as those using hydrocarbon fuel. It is necessary to develop a domestic regulatory document containing fi re safety requirements applicable to hydrogen fi lling stations with account taken of the international experience.
Assessment of operation of safety channel signal cables at nuclear power plants under fire conditions
Authors: Lebedchenko O. S. , Zykov V. I. , Puzach S. V.
Published: July 2021

Introduction. Signal cables of safety systems, installed at nuclear power plants (NPPs), retain the ability to conduct modulated signals during the time period needed to switch the reactor facility to a safe mode. However, the ability of signal cables to transmit signals correctly in the high temperature gas medium, which is typical for the early stage of a room fi re, has not been exposed to research.

Aims and objectives. The co-authors offer a theoretical assessment of the ability of NPP safety system cables to correctly transmit modulated electric signals if exposed to fi re and current loads. The theoretical research into the temperature of the conductor of a signal cable at the initial stage of fi re has been performed towards this end.

Theoretical background. The steady state heat conduction equation, describing heat transmission from the cable core to the environment through the cylinder-shaped insulation layer, is used to measure the temperature of the cable strand.

Results and discussion. Temperature dependences describing the relation between the temperature of the conductor of a single - strand and single-wire cable KNEPng(А)-HF on the gas medium temperature are obtained. Relations between the temperature of the gas medium in the room on fi re and the current intensity in the electric cable (if the cable is laid vertically) are presented with account taken of the dependence between the specifi c resistance of the wire and the temperature if the maximal permissible operating temperature of cable strands is 70 °С, the maximal permissible operating temperature of cable strands in the overload operation mode is 80 °С, and the maximal cable strand heating temperature is equal to 160 °С when the short-circuit failure occurs. Maximal current intensity values are obtained for various operating modes in the condition of temperatures typical for the initial stage of an indoor fire, they allow to correctly conduct modulated signals within the time period needed to switch the reactor facility to a safe mode.

Conclusions. The developed mathematical model and results of numerical experiments allow to assess the infl uence of the temperature in the room of a nuclear power plant in case of fi re on the ability of a signal cable of the safety system to transfer undistorted modulated signals depending on current loads and signal cable laying patterns (whether it is laid vertically or horizontally), and also to expand the range of the room temperature dependence on the current load provided in Electrical Installations Code (EIC).
The efficiency assessment of an automatic sprinkler system
Authors: Tanklevskiy L. T. , Tarantsev A. A. , Zybina O. A. , Babikov I. A.
Published: July 2021

Introduction. Сases of ineffective activation of automatic sprinkler fire-fighting systems (AFFS), designed pursuant to current standards, have made it necessary to address the following three issues: a) identification of reasons for ineffective activation; b) examination of AFFS systems to ensure their successful activation in case of fire; c) making a list of recommendations for AFFS designers. These issues can be resolved with reference to Appendix B to new SP (Construction Regulations) 485.13130.2020.

Maximal critical height of sprinkler placement. Models of fire development were used to design the roof height limit and the AFFS bulb heating time. If the ceiling height exceeds the limit value, sprinklers cannot be activated in a timely manner. This leads to delays in the AFFS activation, and, as a result, the fire area exceeds the one safeguarded by the sprinkler.

Acceptable sprinkler height. The analysis of fire scenarios and bulb heating models allows to more accurately project the feasibility of timely AFFS activation. This, in turn, allows to solve the three above listed problems.

Using a differential heat detector to activate sprinklers. If it is established that the use of the AFFS, activating sprinklers by means of thermal destruction of a bulb, is ineffective in a given room, the feasibility of forced AFFS activation using a differential heat detector responding to the temperature rise in a room may be considered. The ratios, thus obtained, are applied to identify the acceptable height of premises protected by the AFFS equipped with such detectors. Problem solutions, including the identification of the reason for the ineffective operation of the AFFS, examination of the AFFS in operation, and provision of recommendations to designers, are demonstrated using the exhibition hall as an example.

Conclusions. The above-mentioned problems are resolvable with the help of Appendix B to new Construction Regulations 485.13130.2020 and the above models.
The assessment of extinction mechanisms involving water mist applied to combustible liquids
Authors: Korolchenko D. A. , Puzach S. V.
Published: July 2021

Introduction. A number of problems accompany the development of new extinction methods applicable on the premises of buildings and structures and the use of advanced fire extinguishing agents. Subject-specific studies are needed to solve these problems. They include the identification of general principles of fire extinguishing efficiency and further development of the optimal mode of application of firefighting agents. The purpose of this work is the theoretical assessment of fire extinction mechanisms involving the water mist applied to combustible liquids. The objectives to be accomplished include the equations based on the mass/energy conservation laws and derived for flame zones with account taken of the water mist applied; the assessment of the water flow rate for different combustion mechanisms; comparison of assessment results with experimental data obtained in the process of extinguishing model fire seats that have burning combustible fluids.

Methods of analysis. The calculations involve the equations based on the mass/energy conservation laws and derived for flame zones above the surface of combustibles.

Research results. The author analyzes two fire extinguishing mechanisms that contribute to the suppression of burning in the flame zone: 1) the attainment of the value of mass concentration of water vapour that reaches the lower concentration limit of combustion of the combustible mixed gas (oxygen reduction); 2) cooling combustible mixed gas in the flame zone by evaporating water until the flash point temperature of combustible vapour is reached.

Conclusions: Equations based on mass/energy conservation laws were derived for flame zones, formed in the course of combustion of flammable liquids, with account taken of a jet of water mist. Water flow rates needed for the implementation of various extinguishing mechanisms were analyzed using the proposed equations. Theoretical results were compared with the experimental data obtained in the process of using water mist to extinguish model fire seats that contain combustible fluids.
The problem of relevant social regulation of the technosphere exemplified by fire safety
Authors: Ershov A. V. , Korobko V. B.
Published: July 2021

The article addresses the problem of mainstreaming the state regulation of the technosphere in terms of fire safety assurance and urban development.The technosphere, being an artificial structure created by humans willing to simplify and protect their living, has turned into a major problem rather than a benefit over the last fifty years. Accelerated sociocultural evolution is the reason for this change.Reason 1 is our poor knowledge of the technosphere and its constituents that we are still willing to create and apply using our simplified (conventional) ideas about the natural processes underlying their creation and application.Reason 2 is the logistic breakdown of the technosphere, as a result of which the consolidated sociocultural space is regulated by separate social norms focused on minor fragmented goals, determined by subjective needs of small groups willing to obtain immediate benefits.Reason 3 is decelerated development of the social environment that lags behind industrialization and urbanization. Thus, it is unable to exercise reliable control over the safety of the technosphere.A set of actions, aimed at the expansion of the area exposed to social control and the tightening of penalties represent a practical solution to these problems that is currently applied by executive government authorities.However, social regulation quality improvement, based on the principle of prevention of inacceptable social harm, has been disregarded.The introduction of a risk oriented model into fire safety assurance and urban planning is analyzed in an attempt to consider the problems in question.
The heating of a stream of particles by thermal counter radiation
Authors: Poletaev N. L.
Published: July 2021

Introduction. It is accepted that the depth of heating of the dust/gas/air mixture by the radiation of combustion products SR is equal to the length LR of the free path of radiation in the mixture. Numerical simulation of combustion of a gas-air mixture that has inert particles, taking into account the re-radiation of heat by heated particles of the fresh mixture, led to ratio SR >> LR. In this work, the analytical assessment of ratio χS = SR/LR is performed.One-dimensional problem model. The co-authors determined stationary temperature distribution over the flow of initially cold monodisperse particles suspended in vacuum. Particle velocity V is directed toward a heat-radiating, absolutely black surface that is permeable by particles. Simplifying assumptions are used: radiation consists of two oppositely-directed flows of electromagnetic energy; interaction between particles and radiation is described in the approximation of geometric optics; the temperature inside the particle is the same. Problem solving. It is shown that χS is determined by V=Vcp / (εT 0,5, σTb)3 , where cp, εT, σ, Tb are, respectively, heat capacity per unit volume of the suspended matter, integral emissivity of the particle material, the Stefan-Boltzmann constant, and the surface temperature. For ≤ 2.8, re-emission can be neglected: χS ≈ 1. At ≤ 1.2, temperature distribution regulates re-emission: χS ≈ 5 –1/(2 – εT) >> 1.Solution discussion. The analytical solution satisfactorily describes the available numerical solutions and experimental data for the case of combustion of a dust/gas/air mixture after specifying the parameters of a simplified model: the radiating surface should be understood as the flame front, Tb is the combustion temperature, and cp is the overall heat capacity of the mixture. The estimate ≤ 1.2 indicates the final high temperature of the gas suspension, the possibility of its autoignition far from the flame, and the need to change initial assumptions when simulating re-emission.Conclusions. Analytical evaluations make it possible to employ ratios SR >> LR and SR ≈ LR for the suspension over a thermal radiation source in vacuum. Conditions for the application of the results of simplified simulation of re-emission to the combustion of a dust/gas/air mixture are formulated.
Rational allocation of the resource designated for comprehensive safety assurance at an enterprise: the problem statement
Authors: Gvozdev E. V.
Published: July 2021

Introduction. Corporate resources translate into a strong in-house capacity that ensures sustainable production processes. We present a novel integrated area of activity, whose purpose is to solve problems by identifying the factors of influence, coming from employees of versatile departments (structural units) and focused on industryspecific (sectoral) functions that are part of the comprehensive safety system of an enterprise.Methods of research. The author employed the established methods of comprehensive safety assurance to analyze a number of approaches. He also explored the features of their application. The author also substantiated the choice of the Lagrange multiplier method, used to formulate the problem of rational allocation of the resource designated for the sustainable performance of functions that assure the comprehensive safety of an enterprise.Problem statement. The author addresses the problem of rational allocation of the resource (the labor potential), considered as a factor of influence produced on the sustainable performance of industry-specific (sectoral) functions that comprise the system of comprehensive safety of an enterprise. An exemplary solution. The author offers an example that represents a description of the process of consecutive identification of critical points that are relevant to the impact (a coefficient) produced by the personnel on the sustainable performance of industry-specific (sectoral) functions that contribute to the comprehensive safety of an enterprise.Conclusions. Solutions for specific tasks, forming part of a methodologically described problem, will make it possible to develop a methodology for the synthesis of the comprehensive safety which is adaptable to different conditions of operation of an enterprise (day-to-day operations, as well as threats and emergencies of natural and man-induced origin), and each is of great economic importance for Russia.
A solution to the thermal problem of fire resistance of spun reinforced concrete columns
Authors: Palevoda I. I. , Nekhan D. S.
Published: July 2021

Introduction. Spun reinforced concrete columns are widely used in the present-day international construction practice. Known formulas, used to calculate temperatures of cross sections of reinforced concrete structures, needed to assess their fire resistance limit, are successfully applied to homogeneous structures that have solid sections. However, they are inapplicable to spun reinforced concrete columns due to their structural features. The purpose of this work is to develop a method for solving a thermal problem of spun reinforced concrete columns and adapt existing calculation formulas.Materials and methods. This work addresses the heating of spun reinforced concrete structures in case of fire. Ansys Workbench was employed to perform the computer simulation needed to study the influence of the characteristics of spun reinforced concrete columns on their heating. Results and discussion. In the course of the theoretical studies, the effect, produced by column cavities, the heterogeneity of spun concrete and thin walls of these structures on the heating of their cross sections was assessed with regard for the results of full-scale fire tests of spun reinforced concrete columns. Correction coefficients were obtained in order to take account of these factors. A regression equation was derived as a result of the simulation performed in the context of a full-scale factorial experiment involving coefficient khol, which takes into account the rising temperature of hollow reinforced concrete structures in comparison with solid ones. Khet heating acceleration coefficient is applicable to spun reinforced concrete structures due to the heterogeneity of concrete in the cross section. This coefficient represents a function of the wall thickness. Coefficient kth, which allows for the heating acceleration in the course of crack opening in thin-walled structures, varies in the range of 1.00…1.40. The concrete cracking temperature is 550 °C.Conclusion. A new method allows to solve the thermal problem of fire resistance of spun reinforced concrete columns. The engineering formula used to calculate the temperature in a cross-section was adapted. The results of computer-aided simulation and calculation of temperature values, performed using the adapted formula, show acceptable convergence with the experimental data.
Introduction of a flame suppression pattern into integrated and zone models used to analyze the dynamics of hazardous factors of indoor fires
Authors: Korolchenko D. A. , Puzach S. V.
Published: July 2021

Introduction. Fire risk calculation is performed to substantiate the compliance of space planning solutions of buildings and structures with fire safety requirements. The calculation of time needed for hazardous factors of fire to block evacuation routes is performed with account for unlimited fire propagation. The only system, whose operation is taken into account if the fire risk value is exceeded, is the smoke ventilation system. The operation of other fire safety systems is disregarded due to the unavailability of reliable engineering methods of analysis of their influence on fire escalation. The problem of development of modified mathematical models, used to analyze the fire escalation pattern, with account to be taken of the process of fire extinguishing and its influence on fire propagation, is relevant. The purpose of this research is to develop common principles that allow to take account of the pattern of fire suppression in solid materials and combustible liquids by fire extinguishing substances having various origins and degrees of dispersion, if the fire extinguishing substances are added to integrated and zone models of development of hazardous factors of fire escalation.Calculation methodology. The calculations are based on the equation compiled in furtherance of principles of conservation of mass and energy in the flame zone above the surface of the combustible material.Research results. The co-authors suggest general principles for the introduction of a flame suppression pattern into integrated and zone models used to analyze the evolution of hazardous factors of indoor fires. The coauthors present the main provisions and parameters needed to modify integrated and zone models in case of different methods of fire extinguishing. The co-authors have analyzed hazardous factors of fire with account for the flame suppression pattern.Conclusions. The co-authors applied the research findings to develop the modified integrated and zone models that allow to analyze the dynamics of hazardous factors of fire with account for the extinguishing of solid materials and combustible fluids by fire extinguishing substances having various origins and degrees of dispersion.
AIMED CONTROL OF THE FREQUENCY SPECTRUM OF EIGENVIBRATIONS OF ELASTIC PLATES WITH A FINITE NUMBER OF DEGREES OF FREEDOM OF MASSES BY SUPERIMPOSING ADDITIONAL CONSTRAINTS
Authors: Lyakhovich Leonid , Akimov Pavel
Published: July 2021

As is known, for some elastic systems with a finite number of degrees of freedom of masses, for which thedirections of motion of the masses are parallel and lie in the same plane, methods have been developed for creatingadditional constraints that purposefully change the spectrum of natural frequencies. In particular, theory and algorithm forthe formation of aimed additional constraints have been developed for the rods, the introduction of each of which doesnot change any of the modes of natural vibrations, but only increases the value of only one frequency, without changingthe values of the remaining frequencies. The distinctive paper is devoted to the method of forming a matrix of additionalstiffness coefficients corresponding to such aimed constraint in the problem of natural vibrations of rods. This method canalso be applied to solving a similar problem for elastic systems with a finite number of degrees of freedom, in which thedirections of motion of the masses are parallel, but not lie in the same plane. In particular, such systems include plates.However, the algorithms for the formation of aimed additional constraints, developed for rods and based on the propertiesof rope polygons, cannot be used without significant changes in a similar problem for plates. The method for the formationof design constraint schemes that purposefully change the spectrum of frequencies of natural vibrations of elastic plateswith a finite number of degrees of freedom of masses, will be considered in the next work.
Lipoxygenase activity and antioxidant capacity in pepper (Capsicum annum) exposed to high concentration of copper sulphate
Authors: Koç Esra , Karayiğit Belgizar
Published: July 2021

Excess Cu causes negative effects on plant growth and development by affecting important physiological processes in plants. In this study, the effect of high concentration of copper sulphate (CuSO4) on lipoxygenase (LOX) activity, lipid peroxidation and antioxidant activity in pepper was investigated. The highest amount of LOX activity increase and lipid peroxidation in pepper seedlings’ leaves exposed to CuSO4 was detected 24 h following the application. An early antioxidant response to CuSO4 application occurred, and the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity was detected 3 h after the application and the highest reducing power after 12 h. The increase in malondialdehyde of leaf samples taken 1.5 h and 3 h after the application, along with the increase in LOX activity, reducing power and DPPH scavenging activity (%), showed that CuSO4 stimulates the defence system in a short time. The increased lipid peroxidation, despite generally decreased DPPH fragmentation activity and reducing power in samples taken after 6 h showed that 0.5 M CuSO4 caused high oxidative stress. This result revealed that high CuSO4 concentrations may also disturb the non-enzymatic antioxidant capacity.
Tocolytic treatment and childhood allergic disorders: The Japan Environment and Children’s Study
Authors: Murata Tsuyoshi , Isogami Hirotaka , Imaizumi Karin , Fukuda Toma , Kyozuka Hyo , Yasuda Shun , Yamaguchi Akiko , Sato Akiko , Ogata Yuka , Shinoki Kosei , Hosoya Mitsuaki , Yasumura Seiji , Hashimoto Koichi , Nishigori Hidekazu , Fujimori Keiya
Published: July 2021

Background: This study aimed to evaluate differences in maternal
characteristics and obstetric and childhood outcomes between term births
according to the use of tocolytic treatment. Methods: This study
analyzed the data of the participants enrolled in the Japan Environment
and Children’s Study between 2011 and 2014. Data of 63,409 women with
singleton births after 37 weeks of gestation were analyzed. We compared
maternal characteristics, obstetric outcomes, and childhood outcomes
between term births with tocolytic treatment and those without tocolytic
treatment. Multiple logistic regression was used to calculate adjusted
odds ratios for childhood outcomes with significant between-group
differences in the univariable analysis for term births with tocolytic
agents, with term births without tocolytic agents as the reference
group. Results: In term births with tocolytic agents, participants had
significantly younger age, leaner body mass index, higher oxidative
stress during pregnancy, shorter pregnancy period, lighter neonatal
birth weight, lower incidence of gestational diabetes mellitus, higher
incidence of preterm premature rupture of membrane, higher rates of
cesarean section, lower incidence of meconium-stained amniotic fluid
during pregnancy, and higher incidence of childhood allergic disorders.
The incidence of childhood developmental disorders showed no significant
between-group differences. The adjusted odds ratio for childhood
allergic disorders in term births with tocolytic agents was 1.09 (95%
confidence interval, 1.04-1.14). Conclusions: This study found no
significant association between tocolytic treatment and the incidence of
childhood developmental disorders in children with term births. However,
tocolytic treatment showed an association with a slightly increased
incidence of childhood allergic disorders.
A Rare Anatomical Variation Complicating A Diffuse Abdominal Pain Presentation: Colonic Perforation in Situs inversus totalis
Authors: Elfanagely Omar , Elfanagely Yousef , Pratt Abimbol
Published: July 2021

Situs inversus totalis (SIT) is a rare anatomical variation of the
thoracic and abdominal organs. We report a case of a 93-year-old woman
who presented with pneumoperitoneum secondary to stercoral colonic
perforation requiring emergent Hartman’s procedure.
Erratum: Asthma prevalence and the impact of nutritional status on prescribed asthma medications in children
Authors: Editorial E
Published: July 2021

Unfortunately, the article by Vesna PETROVIC, Vesna VUJIC ALEKSIC, Tanja
ROZEK MITROVIC and Aleksandra HRISTOV, published in the Medical Review, 73;
9-10, 2020, contained two errors: 1. On page 267, the title of the paper
should read: PREVALENCE OF ASTHMA AND THE INFLUENCE OF NUTRITIONAL STATUS ON
PRESCRIBED MEDICINES FOR ASTHMA IN CHILDREN, and 2. In Table 1, in the
Section ?Others?, percents 57.9 and 8.9 are in the column for No/Br instead
in the column for percentages. At the request of the authors, we hereby
publish corrections.

 Link to the corrected article 10.2298/MPNS2010265P
The Ethics Interview: Can a Single Interview Exercise Help Students Experience the Benefits of Professional Engagement?
Authors: Killian Larita J. , Monje-Cueto Fabiola , Huber Marsha M. , Brandon Christopher
Published: July 2021

Professional engagement helps students develop professional judgment, connect their coursework to the “real world,” and explore accounting-related careers. Internships often provide a route to these benefits, but some students cannot complete internships. The Pathways Commission calls for new, creative approaches to professional engagement. In the ethics interview exercise, students engage with professionals for a single interview. Following the intentional learning model, students complete activities before and after the interview. They select the interviewee, prepare questions about ethics and topics of personal interest, organize and conduct the interview, and reflect on the experience. We implemented the exercise in different accounting courses at universities in the United States and Bolivia, using both face-to-face and virtual interviews. We applied principles of phenomenology for assessment. Results indicate the exercise helps students experience the benefits of professional engagement. The exercise requires little modification to existing courses and can be modified to support varied learning goals.
Ultrafast laser ablation of silicon with ∼GHz bursts
Authors: Matsumoto Hisashi , Lin Zhibin , Schrauben Joel N. , Kleinert Jan
Published: July 2021

The authors report on processing silicon with bursts of hundreds of subpicosecond pulses with an intraburst pulse repetition frequency of 0.86 GHz at 515 nm. They find that the burst-to-burst overlap is a key parameter in optimizing the ablation efficiency for the line scribing and milling processes, contrary to traditional nonburst ultrafast processes. A nanosecond laser reference experiment and the corresponding multiphase simulations demonstrate that this behavior is directly related to the hydrodynamic effects of the molten material generated during the laser processing. Exploring the hole and scribe morphology with scanning transmission electron microscopy and selective area electron diffraction yields a surprise: holes show no sign of a polycrystalline or amorphous heat affected zone, while scribed lines clearly do. The multiphase modeling provides a likely explanation—it is not “ablation cooling.”
Environmental variables affect the diversity of adult damselflies (Odonata: Zygoptera) in western Amazonia
Authors: Brito Joás , Calvao Lenize , Cunha Erlane , Maioli Leandro , Barbirato Mayla , Rolim Samir , Juen Leandro
Published: July 2021

Our study evaluated the effects of environmental variables on the assemblages of the suborder Zygoptera, and tested the hypothesis that environmental variables are more important determinants of the structure of these assemblages than limnological variables in streams. We sampled 17 streams in the Carajás National Forest and tested our hypothesis using a linear regression analysis, with the zygopteran species composition, richness, and abundance as the response variables. Our findings indicate that both limnological and physical variables influence, independently, the characteristics of the zygopteran assemblages. The riparian forest maintains the stability of the environment and provides dispersal corridors, along which the zygopterans can reach alternative, suitable environments. The small scale of this study also implies that the continuity of the vegetation is essential for the dispersal of the zygopterans among different landscapes. The high levels of abundance recorded in the better-preserved environments may reflect the maintenance of specific habitats and resource availability. Riparian forest is crucial to the ecological equilibrium of the stream systems, although further research at a broader spatial scale that focuses on a greater diversity of variables should provide more robust insights into the phenomenon.
The Effect Of Information Technology on Employee Performance in Universities During The New Normal Era Of Covid-19
Authors: Sulistyawati Upik Sri , Bahruni Bahruni
Published: July 2021

Covid has had an impact on the lives of employees generally including university employees. Social restrictions have posed a serious problem with regard to employee performance. In order to maximize employee performance, it is necessary to use information technology in the new normal life. The purpose of this study was to find out the effect of the use of information technology (X) on employee performance (Y). The subject of the research was employees of Sabang College of Economics in Banda Aceh and the Indonesian College of Informatics management in Banda Aceh. The type of the research used was explanatory research with a quantitative approach. The samples were 46 respondents at Sabang College of Economics in Banda Aceh and Indonesian College of Informatics management in Banda Aceh. The data analyses are descriptive analysis, inferential analysis, and multiple linear regression. The sampling technique used is saturation sampling. The results concluded that the independent variables have a significant influence on employee performance simultaneously and partially. Thus, of the two independent variables, efficacy has the most dominant influence on employee performance. The use of IT has the largest beta coefficient and t count. The results of multiple linear regression concluded that the independent variable has a significant influence on the dependent variable, namely employee performance, which is 64.7%. The remaining 35.3% is another variable that can affect employee performance. Other variables that can influence employee performance include employee motivation and ability. Information Technology has had some bearing on employee performance in universities during this the new normal life of Covid-19 period.
Exercício na Doença Arterial Periférica
Authors:   Centro Hospitalar Universitário Lisboa Norte, Hospital de Santa Maria, Lisboa, Ferreira Pedro , Cadilha Rui ,   Centro de Reabilitação do Norte – Dr. Ferreira Alves, Valadares.
Published: July 2021

A claudicação intermitente  é o principal fator limitante da capacidade funcional em doentes com doençaa arterial perif rica dos membros inferiores. Várias modalidades de exercício demonstraram produzir uma melhoria dos sintomas e da distância percorrida durante a marcha. Conhecer os métodos de treino existentes, os seus benefícios e a sua correta prescrição é fundamental para melhorar a qualidade de vida e prognóstico funcional destes doentes.
On approach to determine the internal potential and gravitational energy of ellipsoid
Authors:   Department of Cartography and Geospatial Modeling, Institute of Geodesy, Lviv Polytechnic National University, Fys М. M. , Brydun А. M. ,   Department of Cartography and Geospatial Modeling, Institute of Geodesy, Lviv Polytechnic National University, Yurkiv М. I. ,   Department of Cartography and Geospatial Modeling, Institute of Geodesy, Lviv Polytechnic National University
Published: July 2021

Formulas are derived for the calculation of the potential of bodies, which surface is a sphere or an ellipsoid, and the distribution function has a special form: a piecewise continuous one-dimensional function and a three-dimensional mass distribution. For each of these cases, formulas to calculate both external and internal potentials are derived. With their help, further the expressions are given for calculation of the potential (gravitational) energy of the masses of such bodies and their corresponding distributions. For spherical bodies, the exact and approximate relations for determining the energy are provided, which makes it possible to compare the iterative process and the possibility of its application to an ellipsoid. The described technique has been tested by a specific numerical example.
Quasi-maximum likelihood estimation of the Component-GARCH model using the stochastic approximation algorithm with application to the S&P 500
Authors:   IPIM, National Schools of Applied Sciences, Khouribga, Sultan Moulay Slimane University, Morocco, Settar A. , Fatmi N. I. ,   IPIM, National Schools of Applied Sciences, Khouribga, Sultan Moulay Slimane University, Morocco, Badaoui M. ,   IPIM, National Schools of Applied Sciences, Khouribga, Sultan Moulay Slimane University, Morocco; LaMSD, Higher School of Technology, Oujda, Mohammed First University, Morocco
Published: July 2021

The component GARCH (CGARCH) is suitable to better capture the short and long term of the volatility dynamic. Nevertheless, the parameter space constituted by the constraints of the non-negativity of the conditional variance, stationary and existence of moments, is only ex-post defined via the GARCH representation of the CGARCH. This is due to the lack of a general method to determine a priori the relaxed constraints of non-negativity of the CGARCH($N$) conditional variance for any $N\geq 1$. In this paper, a CGARCH parameter space constructed from the GARCH(1,1) component parameter spaces is provided a priori to identifying its GARCH form. Such a space fulfils the relaxed constraints of the CGARCH conditional variance non-negativity to be pre-estimated ensuring the existence of a QML estimation in the sense of the stochastic approximation algorithm. Simulation experiment as well as empirical application to the S\&P500 index are presented and both show the performance of the proposed method.
Modeling the reinforced concrete shell with a protective structure
Authors:   Lviv Polytechnic National University, Karhut I. I. , Krochak O. V. ,   Lviv Polytechnic National University, Maksimovich S. B. ,   Lviv Polytechnic National University
Published: July 2021

The results of the mathematical modeling and experimental studies for the stress-strain state of the annular section of the reinforced concrete shell with the protective structure are presented. Computer simulation has been formulated as a stationary temperature problem. The distribution of deformations and stresses is shown using the equations of the elastic theory. A comparison of theoretical dependences on the results of experimental studies of physical models is given. Conclusions are drawn about the possibility of using them in the calculations of reinforced concrete protective structures.
Asymptotic stepwise solutions of the Korteweg--de Vries equation with a singular perturbation and their accuracy
Authors:   Taras Shevchenko National University of Kyiv, Lyashko S. I. , Samoilenko V. H. ,   Taras Shevchenko National University of Kyiv, Samoilenko Yu. I. ,   Taras Shevchenko National University of Kyiv, Gapyak I. V. ,   Taras Shevchenko National University of Kyiv, Orlova M. S. ,   Borys Grinchenko Kyiv University
Published: July 2021

The paper deals with the Korteweg-de Vries equation with variable coefficients and a small parameter at the highest derivative. The asymptotic step-like solution to the equation is obtained by the non-linear WKB technique. An algorithm of constructing the higher terms of the asymptotic step-like solutions is presented. The theorem on the accuracy of the higher asymptotic approximations is proven. The proposed technique is demonstrated by example of the equation with given variable coefficients. The main term and the first asymptotic approximation of the given example are found, their analysis is done and statement of the approximate solutions accuracy is presented.
Mathematical modeling of centrifugal machines rotors seals for the purpose of assessing their influence on dynamic characteristics
Authors:   Pukhov Institute for Modelling in Energy Engineering of the National Academy of Sciences of Ukraine, Shevchenko S. S.
Published: July 2021

With an increase of equipment parameters, such as the pressure of the sealing medium and the speed of shaft rotation, the problems ensuring its hermetization efficiency are rising up. In addition to hermetization itself, the sealing system affect the overall operational safety of the equipment, especially vibratory. Groove seals are considered as hydrostatodynamic supports capable of effectively damping rotor oscillations. To determine the dynamic characteristics, models of grooved seals and single-disc rotors with grooved seals are examined. The obtained analytical dependences for computation of dynamic characteristics for the hydromechanical rotor-seals system, describing radial-angular oscillations of the centrifugal machine rotor in groove seals are presented as well as the formulas for computation of amplitude frequency characteristics. An example for the computation dynamic characteristics of one of the centrifugal machine rotor models is drawn.
The offer of corporate social responsibility and business ethics courses in university accounting undergraduate programs: A comparative analysis among administrative sciences
Authors: Buele Nugra Irene , Pesantez Andrea
Published: July 2021

Business failures in the 1980s, in the United States, have prompted the undergraduate programs of Business Administration, Public Administration, Foreign Trade, Accounting and Auditing, Economics, Finance, Management and Leadership, Human Talent Management, Transportation Management, Business Management, Marketing, International Business and Tourism to strengthen the techniques and processes of education of the future professionals, based on the teaching of social responsibility and ethics.  Hence, the main purpose of this research is to analyze the presence of subjects related to Business Ethics and Corporate Social Responsibility (CSR) at Universities and Polytechnic Schools that are within the National Public and Private classification, and which receive allocations and revenues from the State in Ecuador.  For this purpose, null hypotheses (Ho) and alternative hypotheses (H1) have been proposed, obtaining significant statistical evidence in the analysis of 89 curricula of administrative science programs.  The analysis shows that the offer of the 47 studied subjects of social responsibility, and 75 of ethics does not depend on whether the university is public or private to receive allocations and revenues from the State, but it does depend on the type of program or degree that is being offered. These higher education subjects are important to help, the future professional, remember his or her correct behavior, commitment, and actions in the company, in society, and in the environment.
THE IMPACT OF COVID-19 PANDEMIC ON THE ECONOMIC ACTIVITY OF PURSE SEINE FISHERMAN IN BANABUNGI VILLAGE, KADATUA DISTRICT, SOUTH BUTON REGENCY
Authors: Sidiq Azwar , Annaastasia Nurhuda , Sarifin Abdul , Yusnita Yusnita
Published: July 2021

Fisherman are a group of people who are highly dependent on the fisheries resources in their efforts to fulfill their basic needs and to be a prosper. The outbreak of the Covid-19 not only threatens people’s lives and safety, but also has a significant impact on economic development both of which are  macro and micro to be weakened. This research aims to determine the impacts of the Covid-19 Pandemic on Fishing activities, incomes, and marketing activities of purse seiner. The research was conducted on October 2020 in the Banabungi Village, Kadatua Subdistrict, South Buton Regency, Southeast Sulawesi Province. The results show that the impact of the Covid-19 has affected purse seiner’s fishing activities where production costs have increased by 4,62%, The of crews (ABK) have increased by 19,69%, and marketing at channel I (Producer-Wholesale)stopped. Consequently, where the change in fish price at fishemen level by 79,75%. The margin of marketing at channel II at wholesale level is IDR 5.556/kg. Meanwhile, at retail level is IDR 8.267/kg. Production was decreased by 79,93%, revenue decreased by 64,06% and profit decreased by 68,26% with value of R/C ratio 3.70 >1. The fishing location of fishermen has not change as in the previous year. Marketing volume during the peak fishing season is 14.809kg/month.
ANALISIS KEMAMPUAN KOMPETENSI STRATEGIS MATEMATIS SISWA PADA MATERI PERSAMAAN DAN PERTIDAKSAMAAN LINEAR SATU VARIABEL
Authors: Aulia Marina Puspa , Roesdiana Lessa , Haerudin Haerudin
Published: July 2021

The object of this research is to understand the strategic competence of the students in the parallel materials and linear equations of one variable in the SMPN 3 Karawang Barat in solving the story quiz. The eighth-graders of SMPN 3 Karawang Barat are the subject of this report. It is a qualitative study with a descriptive approach. A method for data collection is the strategic competence test. The student's assessments are scored and the problem analysis is carried out to understand the markers of a strategic mathematical skill that requires the ability to understand the situation and conditions of a problem, to choose an acceptable presentation to help solve the problem. Research indicates that the student category already able to fill all of the indicators of mathematical strategic competence is 18.9%, the student who has been able to fill some indicators is 67.6% and the student who has not yet been able to fill all indicators is 13.5%. Therefore, the strategic competence of mathematically of class VIII H of SMPN 3 Karawang Barat is still in the moderate category
ANALISIS MISKONSEPSI SISWA KELAS VI SD NEGERI GUNUNG PASIR JAYA PADA MATERI PECAHAN
Authors: Saputri Maria Edistianda Eka
Published: July 2021

The concept of fractions is one of the basic materials that students must master since elementary school level. Fractions contain many rules in the form of axioms, definitions, theorems, formulas, and algorithms, this can lead to misunderstanding of concepts by students. Conceptual errors that occur in students due to not understanding the concept are called misconceptions. If there is a student's misconception of this material, it will hinder the understanding of concepts related to fractions, or there can be more misconceptions, and it can lead to a decrease in student learning outcomes. The purpose of this study is that teachers can find out early on any misconceptions related to fractions that often occur so that teachers can evaluate and correct these misconceptions. The method used in this research is the descriptive method. Data collection techniques in research using description tests and data analysis techniques by reducing data. From the data, it was found that most students experienced misconceptions in the sub material of basic fraction operations, namely the addition and multiplication of fractions. However, in almost all sub-materials, more than 50% of students experienced conceptual errors. The most common type of misconception is using the wrong concept in applying the concept to a certain procedure or operation.
PENGEMBANGAN LEMBAR KERJA PESERTA DIDIK MATERI KELILING DAN LUAS BANGUN DATAR MENGGUNAKAN KALKULATOR DENGAN PEMBELAJARAN DELIKAN
Authors: Wardhani Oktalisa Putri , Irianto Sony
Published: July 2021

This research is a research development (Research and Development) that aims to determine the feasibility of LKPD Mathematics products as well as the supporting and inhibiting factors of using LKPD. This study uses the Borg and Gall development model. The instruments used were tests, interviews, and questionnaires. There are 3 types of questionnaires used, namely expert validation questionnaires, student response questionnaires, and teacher response questionnaires. The results of the validation that have been carried out by the three validators obtained an overall average value of 4.16 with valid criteria. The LKPD trials were carried out by the Delikan learning steps (listen, see, and do). The average score of the students' questionnaire response was 4.58 with very good criteria. The teacher response questionnaire to the mathematics LKPD obtained a result of 4.2 with a good category. The use of LKPD received a very good response from students because the use of calculators was something new, but some students did not understand the concept of multiplication and long division so they needed guidance from the teacher. LKPD Mathematics of the circumference and area of a flat shape using a calculator with Delikan learning in Class IV SD UMP is said to be feasible and can be used as an alternative teaching material to improve skills in calculating the circumference and area of a flat shape using a calculator calculating tool.