Impact action of a projectiles on special protective structures and ways to increase their protective capacity

A method for studying the reaction of elastic elements of protective structures to a series of impact actions of shells has been developed. In the work, the elastic elements of the protective structure are modeled by homogeneous beams, and the dynamic action of the shells is simulated by instantaneous point-applied forces. A mathematical model of this dynamic process is constructed, which is a boundary value problem for a hyperbolic equation with an irregular right-hand side. The latter is described using Dirac delta functions. Cases of both fixed and free ends of protective elements are considered. The main ideas of perturbation methods are used for the researches carried out in the work. Analytical dependences for the description of elastic deformations of a protective element which are basic for definition of its strength characteristics are received. They and the graphical dependences built on their basis for specific cases show that the dynamic deformations of the protective element for the fixed ends are greater in the case of the projectile closer to its middle, at the same time for the free ends – closer to the end. With regard to the modernization of protective structures, the dynamic effect on their elements can be reduced by using elastic reinforcement or changing the method of fixing the ends of the protective element: elastic or with a certain angle of inclination of the bearing surfaces. It is proposed to use special plastics, soil layer, flexible wood flooring, etc. as elastic reinforcement. The technique used in the work is the basis for determining the strength characteristics of protective elements, and from so – to check the reliability of the protective structure; study of the dynamics of protective and similar types of structures, taking into account the nonlinear characteristics of the elastic elements of protective structures; study of more complex oscillations of elements of protective structures. In the case of a series of impacts, it is obvious that the amplitude of deflection of the protective element after each impact will increase over time, because the model does not take into account the force of viscoelastic friction. These tasks will be the subject of further research.

Behaviours involved in the role of victim and aggressor in bullying: Relationship with physical fitness in adolescents

Physical fitness is related to well-being and health. Adolescence is a key period in the psychological and social development of the person, in which interpersonal relationships gain strength, being bullying a type of violence that can affect the personality of those involved. At present, there is not enough research to determine the relationships between bullying and physical condition. The purpose of this study is to find out if there are any relationships among physical fitness, victimisation, and aggression in bullying, and to identify these behaviours. This is a descriptive study done in 1035 adolescents aged 12 to 17 years (M = 14.67, SD = 1.49). The European Bullying Intervention Project Questionnaire (EBIPQ) scale was used, and anthropometric characteristics of weight and height were measured. In addition, physical fitness tests from the Eurofit battery, sit-and-reach, 30-second sit-ups, horizontal jump, manual dynamometry, and 20-meter Multistage Shuttle Run Test (SRT) were included. The relationships between variables were analysed using Spearman correlations, linear regressions, and ordinal regressions. The most relevant findings indicate an inverse relationship between being a victim of bullying and having a better cardiorespiratory cardiovascular endurance. These also show a direct relationship between being a bully and skeletal muscle strength measured through the horizontal jump, 30-second sit-ups, and manual dynamometry tests. Theoretically, we can conclude that physical condition can be considered a predictor to consider in bullying. Specifically, cardiorespiratory fitness, in addition to its multiple physical and mental benefits, may be a protective element against bullying victimisation. In contrast, muscular strength, especially in boys, may be an important predictor, especially in the physical component, of aggression in bullying.

Characteristics and Associated Factors of Burn-out among Moroccan Dentists

Objective: Burnout is a real threat for healthcare professionals and is growing exponentially in our modern societies. Our study aims to determine the prevalence of burnout among dentists in Rabat, Sale, and Kenitra region and look for the associated factors.Method: This is a descriptive and analytical cross-sectional epidemiological study carried out in 2019 with a group of 120 dentists using a self-administered questionnaire; burnout was assessed by the French version of the Maslash Burnout Inventory (MBI).Results: A total of 100 dentists participated in the study (response rate of 83.33%) with a female predominance at 56% and an average age of 38 years. Severe burnout affected 25% of participants, and only 3% presented low burnout for all three dimensions (According to Maslach's Burnout Inventory). The percentages of the MBI sub-dimensions were as follows: 47% had high emotional exhaustion, 51% had high depersonalization, and 42% had low personal fulfillment. High depersonalization was associated with unmarried status (p = 0.019) and working alone (p = 0.002).Conclusion: 25% of the dentists in our study were affected by severe burnout, which presents a worrying result proving that burnout is a reality in our country. The contributing factors were working alone in the office and being unmarried, and the essential protective element seemed to work in association.

Habitability, Resilience, and Satisfaction in Mexican Homes to COVID-19 Pandemic

Following the 2020 confinement due to the COVID-19 pandemic, housing has become the only safe place and this has exposed inequity in habitability. This research on the reality of confined households and the perception of their homes in the Mexican republic is based on a mixed participatory study, combining quantitative and qualitative approaches. The online questionnaire consisted of 58 questions in the quantitative approximation. The qualitative part required the provision of an image of the workspace, with testimonies and personal reflections. During the lockdown, all participants saw an increase in overall energy consumption; more than half reported not being in thermal comfort; and a third declared deficiencies in noise insulation. Regarding the perception of the telework/tele-study space, we found the following categories: bedrooms, living/dining rooms, studies and others. In addition, respondents had often adapted the workspace for both individual and shared use. In general, the households were satisfied with the size of their houses but would like landscaped spaces or better views outside. Confinement made housing the protective element against the pandemic. The consequences will have an effect globally, so new architectural design paradigms need to be rethought.

Redeployment during the first wave of the COVID-19 pandemic: implications for a clinical research workforce

Background: Health professionals are considered a group vulnerable to developing mental health symptoms during a pandemic, with redeployment being a risk factor. However, previous literature suggests workplace communication can be a protective element. Aims: An audit aimed to evaluate NHS research staff's experiences of redeployment in order to provide suggestions for future improvements in the process. Methods: A questionnaire was disseminated to all staff in the clinical research directorate of an NHS trust. Responses were analysed using thematic analysis. Findings: Over half the redeployed staff experienced perceived negative psychological outcomes. The main reported contributor to this was perceived lack of communication. Conclusion: Communication needs to be improved in future redeployments. Future research should consider a larger cohort and more input from team members who remained on the pre-COVID-19 studies in order to improve the transition back from redeployment.

Technical possibilities for recycling plastics from agribusiness

Plastic waste generated by the Ecuadorian agro-industrial sector represents one of the main environmental impacts, particularly in floricultural and banana production, as a result of its use as a greenhouse cover and as a protective element for the fruit cluster, respectively. The situation become more complicated because of the level of degradation caused by environmental exposure and the degree of contamination due to the use of agrochemicals that plastics present once their useful life has expired. The current research was divided into two stages: characterization of plastic waste and conditioning prior to reprocessing. The results revealed the plastic waste of the floricultural and banana sector, whose predominant material corresponds to LDPE and HDPE, respectively, presents a level of contamination that allows them to be considered as “non-hazardous” waste, which allows them to be recycled, but their processes must be properly controlled and carried out by qualified people. The level of degradation in the exposed banana bags showed losses of mechanical properties of tensile less than 50%, which means that the material is not degraded and it is feasible to recycle it directly. Additionally, the FTIR-ATR spectra on both sides of the film in the samples did not register representative bands of oxidation. On the other hand, in the greenhouse waste, the losses of mechanical properties of tensile strength above 50% as well as the noticeable formation of carbonyl groups in the structure of the material showed the degradation of the plastic. Therefore, the feasibility of recycling will depend on the incorporation of virgin material. The conditioning of the waste for subsequent recycling revealed the need of a washing process consisting of four stages: initial cleaning, pre-wash, washing, and air-drying.

On ways to increase protection of special structures from impact action

The technique of research of dynamic processes of elements of engineering constructions of special purpose from explosive action of projectiles is developed. Elastically reinforced beams with hinged ends were chosen for the physical model of elements of engineering structures. It is assumed that the elastic properties of the latter satisfy the nonlinear technical law of elasticity. A mathematical model of the process of a series of impact actions of projectiles at different points of the element of the protective structure is constructed. The latter is a boundary value problem for a partial differential equation. Its peculiarity is that the external dynamic action is a discrete function of linear and time variables. To determine the dynamic effect of a series of impacts on the object under study, and thus the level of protection of the structure, the basic ideas of perturbation theory methods are extended to new classes of systems. This allowed to obtain an analytical dependence of the deformation of the elastically reinforced element on the basic physical and mechanical characteristics of the material of the protective element, its reinforcement and the characteristics of the external action of the projectiles. It is shown that the most dangerous cases, given the security of the structure, are those when the impact is repeated at equal intervals, in addition, the point of impact is closer to the middle of the protective element. The obtained theoretical results can be the basis for selection at the stage of designing the main physical and mechanical characteristics of the elements of engineering structures and their reinforcement in order to reliably protect personnel and equipment from the maximum possible impact on it of the shock series of projectiles. The reliability of the obtained results is confirmed by: a) generalization of widely tested methods to new classes of dynamical systems; b) obtaining in the limit case the consequences known in scientific sources concerning the linearly elastic characteristics of the elements of protective structures; c) their consistency with the essence of the physical process itself, which is considered in the work.

Could Antigen Presenting Cells Represent a Protective Element during SARS-CoV-2 Infection in Children?

Antigen Presenting Cells (APC) are immune cells that recognize, process, and present antigens to lymphocytes. APCs are among the earliest immune responders against an antigen. Thus, in patients with COVID-19, a disease caused by the newly reported SARS-CoV-2 virus, the role of APCs becomes increasingly important. In this paper, we dissect the role of these cells in the fight against SARS-CoV-2. Interestingly, this virus appears to cause a higher mortality among adults than children. This may suggest that the immune system, particularly APCs, of children may be different from that of adults, which may then explain differences in immune responses between these two populations, evident as different pathological outcome. However, the underlying molecular mechanisms that differentiate juvenile from other APCs are not well understood. Whether juvenile APCs are one reason why children are less susceptible to SARS-CoV-2 requires much attention. The goal of this review is to examine the role of APCs, both in adults and children. The molecular mechanisms governing APCs, especially against SARS-CoV-2, may explain the differential immune responsiveness in the two populations.

Study of dynamics and rigidity of multifunctional coating of protective element of aircraft

In this work using a finite element study the author has numerically solved the problem of the dynamic behavior of a multifunctional coating of an aircraft protective element. The researcher conducted the simulation using the Femap with NX Nastran software package, The result of the modal analysis is the values and patterns of natural and secondary vibration modes of the multifunctional coating of the protective element of the aircraft using a special module the author has determined the distribution of effective modal masses in tabular form, Also, as a result of calculations, the author of the article obtained the value of the structural rigidity of the protective coating, The results presented in this work allow us to analyze the behavior of protective systems and structural elements of an aircraft with a multifunctional coating applied to the outer surface in real operating conditions, The design team can use the research results of this article in order to increase the efficiency of the development of a new structures and structures of a composite coating for multifunctional purposes, protective elements and materials for space technology

Функции змеи в обрядовом фольклоре монгольских народов

Introduction. In mythologies of the world, the image of the snake ranks among the most studied characters and has various interpretations. In folklore of Turko-Mongols, it has also been a subject of multiple analyses. Still, the article makes a first attempt at revealing the image of the snake as a taboo sacred character in ritual folklore of the Mongolic peoples. Goals. The paper primarily seeks to identify functions of the snake therein, delineate the symbolic framework, reveal positive and negative connotations. Materials and Methods. The main research method employed is that of comparative analysis instrumental in examining the image of the snake as a semiotic sign. Interdisciplinary analysis of ethnographic and folklore materials, as well as comparisons to Turkic ritual actions, expand the boundaries of identifying the semantics of the image. Results. The snake in shamanic mythology of the Mongolic peoples appears in the hypostasis of the otherworldly Spirit closely associated with the shaman. Images of snakes in cave drawings, petroglyphs, shamanic ongons (sanctuaries), and costumes emphasize their sacred function. In shamanic practice, a snake image can be used as a protective element in the form of a walking-stick or whip. Symbolically, a snake in the form of straps implies a connotation of the animal’s magical abilities. The role of a mediator between worlds allows the snake simultaneously performing the function of a protective force. Functions of the snake in rites are interchangeable and complement each other. Shamanic texts of the Mongolic peoples consistently mention the main function of the snake is that of a carrier between worlds, which is closely related to its transforming abilities. Conclusions. The study resumes the snake in shamanic ritual actions of the Mongolic peoples — with positive connotations — functions as an assistant, intermediary, carrier, and envoy from another world that provides communication between realms. It also reveals patterns of transcoding the snake image in different semiotic systems, interconnectedness and interchangeability of sacral reptile functions.