Experimental analysis of ballistic trauma in a human body protected with 30 layer packages made of biaxial and triaxial Kevlar^(■)29 fabrics

Behind armour blunt trauma(BABT)is a body injury resulting from the deformation of the back surface of armour as a result of a bullet impact.In the case of textile body armour,the severity of the injury may depend on the material of the fibres,but also on the geometric structure of the fabric.The article focuses on experimental research into injuries of the human body protected by ballistic packets made of biaxial and triaxial fabrics,during a non-penetrating impact from a Parabellum 9 mm×19 mm Full Metal Jacket(FMJ)bullet,at a speed of 406±5 m/s.In experimental research,the fabrics had a comparable surface weight and were made of the same Kevlar^(■)29 yarn.The ballistic packages were made of 30 layers.As part of the work,a physical model of the human body was developed.The human body model consisted of a model of the heart,lungs,and skeletal and muscular systems.During the bullet impact,the pressure forces were recorded using sensors located at selected points of the human body.The bullets hit five selected places on the body that were considered critical,from the point of view of maintaining a human’s vital functions.It was found that,during firing,pressure increases both at the site of impact and in the internal organs,which can lead to multi-organ damage.As a result of the experimental analysis,it has been shown that the pressures exerted on specific organs are always lower in the case of body protection with a ballistic packet made of triaxial fabrics,compared to a packet made of biaxial fabrics.

Molecular dynamics-driven exploration of peptides targeting SARS-CoV-2,with special attention on ACE2,S protein,M^(pro),and PL^(pro):A review

Molecular dynamics(MD)simulation is a computational technique that analyzes the movement of a system of particles over a given period.MD can provide detailed information about the fluctuations and conformational changes of biomolecules at the atomic level over time.In recent years,MD has been widely applied to the discovery of peptides and peptide-like molecules that may serve as severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)inhibitors.This review summarizes recent advances in such explorations,focusing on four protein targets:angiotensin-converting enzyme 2(ACE2),spike protein(S protein),main protease(M^(pro)),and papain-like protease(PL^(pro)).These four proteins are important druggable targets of SARS-CoV-2 because of their roles in viral entry,maturation,and infectivity of the virus.A review of the literature revealed that ACE2,S protein,and M^(pro) have received more attention in MD research than PL^(pro).Inhibitors of the four targets identified by MD simulations included peptides derived from food and other bioresources,peptides designed using the targets as templates,and peptide-like molecules retrieved from databases.Many of the inhibitors have yet to be validated in experimental assays for potency.Nevertheless,the role of MD simulation as an efficient tool in the early stages of anti-SARS-CoV-2 drug discovery agents has been demonstrated.

New Trends in the Modeling of Diseases Through Computational Techniques

The computational techniques are a set of novel problem-solving methodologies that have attracted wider attention for their excellent performance.The handling strategies of real-world problems are artificial neural networks(ANN),evolutionary computing(EC),and many more.An estimated fifty thousand to ninety thousand new leishmaniasis cases occur annually,with only 25%to 45%reported to the World Health Organization(WHO).It remains one of the top parasitic diseases with outbreak and mortality potential.In 2020,more than ninety percent of new cases reported to World Health Organization(WHO)occurred in ten countries:Brazil,China,Ethiopia,Eritrea,India,Kenya,Somalia,South Sudan,Sudan,and Yemen.The transmission of visceral leishmaniasis is studied dynamically and numerically.The study included positivity,boundedness,equilibria,reproduction number,and local stability of the model in the dynamical analysis.Some detailed methods like Runge Kutta and Euler depend on time steps and violate the physical relevance of the disease.They produce negative and unbounded results,so in disease dynamics,such developments have no biological significance;in other words,these results are meaningless.But the implicit nonstandard finite difference method does not depend on time step,positive,bounded,dynamic and consistent.All the computational techniques and their results were compared using computer simulations.

Numerical Investigation of Malaria Disease Dynamics in Fuzzy Environment

The application of fuzzy theory is vital in all scientific disciplines.The construction of mathematical models with fuzziness is little studied in the literature.With this in mind and for a better understanding of the disease,an SEIR model of malaria transmission with fuzziness is examined in this study by extending a classicalmodel ofmalaria transmission.The parametersβandδ,being function of the malaria virus load,are considered fuzzy numbers.Three steady states and the reproduction number of the model are analyzed in fuzzy senses.A numerical technique is developed in a fuzzy environment to solve the studied model,which retains essential properties such as positivity and dynamic consistency.Moreover,numerical simulations are carried out to illustrate the analytical results of the developed technique.Unlike most of the classical methods in the literature,the proposed approach converges unconditionally and can be considered a reliable tool for studying malaria disease dynamics.

Numerical Analysis for the Effect of Irresponsible Immigrants on HIV/AIDS Dynamics

The human immunodeficiency viruses are two species of Lentivirus that infect humans.Over time,they cause acquired immunodeficiency syndrome,a condition in which progressive immune system failure allows life-threatening opportunistic infections and cancers to thrive.Human immunodeficiency virus infection came from a type of chimpanzee in Central Africa.Studies show that immunodeficiency viruses may have jumped from chimpanzees to humans as far back as the late 1800s.Over decades,human immunodeficiency viruses slowly spread across Africa and later into other parts of the world.The Susceptible-Infected-Recovered(SIR)models are significant in studying disease dynamics.In this paper,we have studied the effect of irresponsible immigrants on HIV/AIDS dynamics by formulating and considering different methods.Euler,Runge Kutta,and a Non-standardfinite difference(NSFD)method are developed for the same problem.Numerical experiments are performed at disease-free and endemic equilibria points at different time step sizes‘ℎ’.The results reveal that,unlike Euler and Runge Kutta,which fail for large time step sizes,the proposed Non-standardfinite difference(NSFD)method gives a convergence solution for any time step size.Our proposed numerical method is bounded,dynamically con-sistent,and preserves the positivity of the continuous solution,which are essential requirements when modeling a prevalent disease.

Heat of absorption of CO_2 in aqueous N,N-diethylethanolamine+ N-methyl-1,3-propanediamine solutions at 313 K

Differential heat of absorption of CO_2 in aqueous solutions of N,N-diethylethanolamine(DEEA) and activated DEEA solutions up to a total concentration of 2 mol·L^(-1) was measured as a function of CO_2 loading at 313.15 K using a reaction calorimeter. In order to analyze the performance of N-methyl-1,3-propanediamine(MAPA)as an activator, DEEA blended solutions containing 0.05, 0.1 and 0.2 mol·L^(-1) MAPA were studied. The heat of CO_2 absorption in single DEEA solutions was unaffected by changing the DEEA concentration in the range of(0.5–2) mol·L^(-1). On the other hand, increasing the concentration of MAPA in aqueous amine mixtures of(DEEA + MAPA) raised the heat of absorption.

Impact of recycling improvement on the life cycle of phosphorus

Access to natural resources is increasingly more difficult and more costly, partly due to their economic significance and to continuous increase of their global consumption in the recent years. In the case of phosphorus (P), which is a critical raw material, geological distribution of its primary nonrenewable source (phosphate rock) is concentrated in particular regions leading to high supply risk of this raw material. In Europe (EU-28), where phosphate rock reserves are scarce, import of phosphorus has been the main source of supply. It means that Europe relies highly on the foreign exporters. From decision makers' perspective, recycling of phosphorus was taken into account as one of the possible solutions to decrease the dependence on imports and extraction of reserves. The question, however, is to what extent does the recycling of phosphorus help in reducing the reliance on typical supply resources? Hence, the main objective of this paper is to quantify the dynamic flow of phosphorus and show potential benefits of its recycling in Europe. This article presents a system dynamics model for representation of the element P flow and helps to quantify to what extent the recycled phosphorus could mitigate its criticality. Analysis of the results supports previous studies indicating the high reliance ofEU on P imports, estimating around 96% as the reliance percentage on imports. The results imply that improving P recycling has the potential to decrease the level of P imports to a certain extent, which may reach 79%.

An Evaluation of Cotinine as an Index of Exposure to Tabacco Smoke in Children with Recurrent Respiratory Tract Infections Using HPLC Method

The authors evaluated the frequency of exposure to tobacco smoke among children suffering from respiratory tract infections. The investigations comprised 141 children aged from 2 months to 6 years that were treated in the 2nd Department of Pediatric and Allergology of Polish Mother’s Memorial Hospital Research Institute in ?ód? (Poland). 69 of them were exposed to tobacco smoke in their home environment. The remaining 72 children came from non-smoking families. 26 (37.7%) individuals among the passive smokers and 15 (20.83%) among the children from non-smoking families suffered from recurrent respiratory tract infections. Cotinine concentrations were evaluated in the group of 69 children using the HPLC-UV method. The determined average cotinine/creatinine index expressed as median was higher in passive smokers with recurrent respiratory infections than among passive smokers with non-recurrent respiratory infections. Moreover, it was stated that the exposure to cigarette smoke was more often among children of younger and less well educated parents as well as living in poor housing conditions. These studies clearly indicate that there is a need for extensive education on the harmful effects of passive smoking and the recurrence of infections.

Properties of Natural Rubber Biocomposities Filled with Alkaline Modified Oat Straw

Novel elastomer biocomposites based on straw fibers (raw or chemically modified) as reinforcing elements ofnatural rubber (NR) were reported and studied. Oat straw fibres with different average lengths were used.Lignocellulose materials were incorporated into the elastomer, before and after chemical surface modificationinvolving sodium hydroxide. Fourier transform infrared spectroscopy (FTIR) and microscopy techniques wereemployed for characterization of fillers. The kinetics of rubber mixtures, as well as rheometric properties ofcompounds were determined. The cross-linking density was executed on the basis of equilibrium solventswellingmeasurements applying the modified Flory–Rehner equation. The morphology of biocompositessamples was analyzed by a scanning electron microscopy. Mechanical characteristic: the values of hardness,tensile strength and attenuation coefficient were also determined. The physical and chemical investigations haveproved the reinforcing effect of treated oat straw on natural rubber vulcanizates.

Probabilistic Issue of Reliability for Power Machinery Operating in Coal Fired Power Plants

The paper presents results of reliability analysis made for lignite fired 370 MW rated power units installed in the Belchatow Power Plant (Poland). The concept of standardized power unit and the method of a histogram with a set number of observations in each class were applied in a study. The study includes analysis of probability distributions of operation times and repair times for the main power unit components. Empirical probability distribution functions have been identified and their parameters estimated in the study. The final forecast includes an estimation of such reliability measures like expected operation time, expected failure rate, average repair time and expected annual failure duration.

CFD Numerical Simulation of Hydrodynamics in a Rotor-Stator Reactor for Biodiesel Synthesis

In this paper a rotor-stator spinning disk reactor for intensified biodiesel synthesis is described and numerically simulated. The reactor consists of two flat disks, located coaxially and parallel to each other with a gap ranging from 0.1 mm to 0.2 mm between the disks. The upper disk is located on a rotating shaft while the lower disk is stationary. The feed liquids, triglycerides (TG) and methanol are introduced coaxially along the center line of rotating disk and stationary disk, respectively. Fluid hydrodynamics in the reactor for synthesis of biodiesel from TG and methanol in the presence of a sodium hydroxide catalyst are simulated, using convection-diffusion-reaction species transport model by the CFD software ANSYS? Fluent v. 13.0. The effects of upper disk’s spinning speed and gap size are evaluated.

Fingertip skin models for analysis of the haptic perception of textiles

This paper presents finite element models of the fingertip skin which have been created to simulate the contact of textile objects with the skin to gain a better understanding of the perception of textiles through the skin, the so-called hand of textiles. Many objective and subjective techniques have already been developed for analysing the hand of textiles;however, none of them provide exact overall information concerning the sensation of textiles through the skin. As the human skin is a complex heterogeneous hyperelastic body composed of many particles, some simplifications had to be made at the early stage of building the models;however, their utilitarian value was maintained. The models relate only to mechanical loading of the skin. They predict a low deformation of the fingertip skin under the pressure of virtual heterogeneous material: acrylic, coarse wool, and steel.

Identification of Modal Loss Factor of a Sandwich Composite Structure with Polyethylene Terephthalate Core in the Aspect of Core Properties Determination

Comparison of the loss factor determination methods of the sandwich composite structure with polyethylene terephthalate core in the aspect of core material rheological parameters identification was the purpose of the study. Three frequency bandwidths n dB: 1 dB, 2 dB, 3 dB methods, the resonant amplitude method and the fit method of the response of the one degree of freedom model system are taken into considerations. Identification procedure, according to ASTM E756-2005 [1] based on experimental studies of the forced vibrations of the composite structure was presented in the paper. To determine the function of the complex shear modulus of the core material, the Nelder-Mead method is applied. Shear modulus and loss factor identification results were presented on the plots in the frequency domain. The results in a quantitative manner set the applied methods and their practical utility in order.

Schiff Bases as Important Class of Pharmacological Agents

Therapeutics are compounds,which do not always exhibit healing powers.They sometimes prevent or control roles.Many compounds,well known or less are treated as the therapeutic agents.Among them,there is a specific group of molecules named commonly as Schiff bases,chemically imines.Schiff bases are aldehyde-or ketone-like compounds in which the carbonyl group is replaced by an imine-HN=СН-or azomethine-NHN=СН-group,they are an important class of compounds for new drug development.Schiff base modifications so far proved to be very effective with increased efficacy and reduced toxicity.Therefore,many researchers have synthesized these compounds as target structures and evaluated their biological activity.The aim of this work was to present some interesting and promising examples of Schiff bases which exhibit biological activity.

Impact of Remote Working on the Employees During COVID-19 Pandemic-Conclusions From Creative Specialists and Software Developers in the Perspective of the Age of Industry 4.0

The objective of the article is identification of similarities in behavior and work attitude toward remote working in times of COVID-19 pandemic.Evaluation is concerned on employees of creative employees from different countries and business sectors.The author conducted research on Polish and American creative specialists,including software developers.Research conducted for this article in the first stage was qualitative,and in the second stage is based on quantitative methodology and secondary data from American research.The qualitative research conducted in Poland and was based on unstructured interviews with open-ended questions in the form of self-report concerning workflows during remote working.The first stage can be used as the starting point to next research of creative specialists from other countries.The quantitative research is based on secondary data from a study conducted among American employees of Microsoft Corporation.It was research made in the form of survey during COVID-19 pandemic(March-May 2020).The conclusions from each of the stages of research were used to create universal conclusions in the form of gathered key similarities and differences in behavior and wellbeing of creative specialist from different countries during remote working.The analysis included Industry 4.0 perspective-like market needs(e.g.building innovation which require a combination of creativity and technical skills)or condition of constant change.The research and analysis also reveals the potential for future research in the other countries and business sectors.

Synthesis and Structural Analysis of Novel Norspermidine Derivatives

A series of new norspermidine derivatives, both nonionic and cationic, have been obtained. Structures of the synthesized compounds have been estab-lished by FTIR, 1H NMR, 13C NMR, 2D NMR, mass spectrometry and elemental analyses. Physicochemical and anti-microbial properties have been discussed.