scholarly journals Calculation of prestressed structures for shock loading

Vestnik MGSU ◽  
2020 ◽  
pp. 482-495
Author(s):  
Vladimir V. Lalin ◽  
Olga N. Pertseva ◽  
Vladimir R. Kamaltdinov ◽  
Gleb V. Martynov ◽  
Daria E. Monastyreva ◽  
...  

Introduction. With the use of prestressing, coatings are made for special-purpose buildings, requiring calculations for extreme impacts. Such impacts include an airplane strike. Modeling of prestressed structures and calculation of shock loads is difficult to implement in classical calculation programs. A universal tool for solving such problems is the PC SOFiSTIK. This software complex allows you to interact with the most modern software solutions. Materials and methods. For the description of the method, special-purpose coating was selected and the strike calculation of the Learjet 23 aircraft was performed. For modeling prestressing, the SOFIPLUS interface is used. To describe the impact, the internal programming language CADINP is used. Results. The nature of the change in the coating deformations in the first seconds of the aircraft crash is presented graphically. Also, iso-ares of internal bending moments of the coating were derived for the selection of reinforcement and the diagram of the moments of the beams from the action of prestressing, taking into account tension losses. Conclusions. SOFiSTIK PC allows you to solve complex engineering problems with a high degree of automation. Thanks to the open source code, it becomes possible to calculate atypical extreme effects. The obtained graphs and diagrams confirm the passage of checks on the limiting states of the coating, and can also be used to design and calculate similar special-purpose structures.

1978 ◽  
Vol 72 (2) ◽  
pp. 452-468 ◽  
Author(s):  
David W. Moore ◽  
B. Thomas Trout

This article examines the dynamics of military promotion and explores its consequences both for individual officers and for military organization. The central argument is that performance, while a necessary standard for acceptability into a rather large pool of officers from which the elite will emerge, is nonetheless a minor influence on promotion and becomes even less discriminating as an officer's career progresses, whereas visibility–the extent to which an individual has developed contacts with peers and superiors who can influence his movement in the organization–begins moderately and eventually becomes the dominant influence. To present this argument, the article first examines the prevailing concepts of performance and seniority and outlines an expanded model of the promotion process. The component variables of that model are applied to three separate military career levels–junior, middle-grade and senior officers–and are traced longitudinally through the entire officer career pattern. Finally, the impact of contextual factors on the model, particularly the differences between wartime and peacetime, is discussed and illustrated with data from general officer promotion in the army. The implications of this theory are significant for civil control of the military. Through the control of access to the elite nucleus represented by the promotion system, especially with the emphasis on visibility, the military is able to sustain a high degree of autonomy. By the time Congress or other civilian actors are able to exercise selection of the military elite, the promotion system has already preselected those individuals who most highly represent military values held by preceding leaders.


Author(s):  
D. I. Smagin ◽  
K. S. Napreenko ◽  
R. S. Savel’ev ◽  
S. V. Grachev

The process of creating an accident-resistant fuel system (AFS) of a helicopter using mathematical modeling is considered. Possibility of applying optimization algorithms in mathematical modeling of parameters of units of accident-resistant fuel system of helicopter in domestic software complex SimInTech is studied. An approach to solving the problem of optimizing given parameters, both in theory and in practice, is described. Results of the simplest optimization of AFS parameters for nominal operation mode are covered, examples of algorithms for selection of unit parameters are shown. This method of researching the system will allow, with a high degree of accuracy, to determine the necessary parameters at the design stage of the system. It is worth noting that the functionality of the developed dynamic mathematical model in the SimInTech software package is sufficient to perform tasks not only of the conceptual design stage, but also of the subsequent stages of the AFS life cycle.


Methodology ◽  
2007 ◽  
Vol 3 (1) ◽  
pp. 14-23 ◽  
Author(s):  
Juan Ramon Barrada ◽  
Julio Olea ◽  
Vicente Ponsoda

Abstract. The Sympson-Hetter (1985) method provides a means of controlling maximum exposure rate of items in Computerized Adaptive Testing. Through a series of simulations, control parameters are set that mark the probability of administration of an item on being selected. This method presents two main problems: it requires a long computation time for calculating the parameters and the maximum exposure rate is slightly above the fixed limit. Van der Linden (2003) presented two alternatives which appear to solve both of the problems. The impact of these methods in the measurement accuracy has not been tested yet. We show how these methods over-restrict the exposure of some highly discriminating items and, thus, the accuracy is decreased. It also shown that, when the desired maximum exposure rate is near the minimum possible value, these methods offer an empirical maximum exposure rate clearly above the goal. A new method, based on the initial estimation of the probability of administration and the probability of selection of the items with the restricted method ( Revuelta & Ponsoda, 1998 ), is presented in this paper. It can be used with the Sympson-Hetter method and with the two van der Linden's methods. This option, when used with Sympson-Hetter, speeds the convergence of the control parameters without decreasing the accuracy.


2019 ◽  
pp. 21-38
Author(s):  
Alexander N. Deryugin ◽  
Ilya A. Sokolov

The paper analyzes the impact of the “model budget” on the problems of intergovernmental relations in the Russian Federation: a high proportion of expenditure obligations of regional and local budgets and a high degree of interregional inequality in fiscal capacity and socio-economic development. It was concluded that the planned broader use of the “model budget” will not solve the problem of unfunded mandates and will lead first to a significant reduction in incentives for regional authorities to develop the territorial revenue base, and then to economic slowdown in the country. As an alternative approach to improving intergovernmental relations, options are being considered for adjusting the parameters of the equalization transfers distribution formula, the procedure for determining their total volume and calculating the budget expenditure index. In solving the problem of unfunded mandates, an equally important role is given to the procedure for preparing a financial and economic rationale for draft laws.


Author(s):  
Manish M. Kayasth ◽  
Bharat C. Patel

The entire character recognition system is logically characterized into different sections like Scanning, Pre-processing, Classification, Processing, and Post-processing. In the targeted system, the scanned image is first passed through pre-processing modules then feature extraction, classification in order to achieve a high recognition rate. This paper describes mainly on Feature extraction and Classification technique. These are the methodologies which play an important role to identify offline handwritten characters specifically in Gujarati language. Feature extraction provides methods with the help of which characters can identify uniquely and with high degree of accuracy. Feature extraction helps to find the shape contained in the pattern. Several techniques are available for feature extraction and classification, however the selection of an appropriate technique based on its input decides the degree of accuracy of recognition. 


2018 ◽  
Author(s):  
C. Coy ◽  
A.V. Shuravilin ◽  
O.A. Zakharova

Приведены результаты исследований по изучению влияния промышленной технологии возделывания картофеля на развитие, урожайность и качество продукции. Выявлена положительная реакция растений на подкормку K2SO4 в период посадки. Корреляционно-регрессионный анализ урожайности и качества клубней выявил высокую степень достоверности результатов опыта. Содержание нитратов и тяжелых металлов в клубнях было ниже допустимых величин.The results of studies on the impact of industrial technology of potato cultivation on growth, yield and quality of products. There was a positive response of plants to fertilizer K2SO4 in the period of planting. Correlation and regression analysis of yield and quality of tubers revealed a high degree of reliability of the results of experience. The contents of nitrates and heavy metals in tubers was below the permissible values.


2018 ◽  
Vol 48 (3) ◽  
pp. 84-90 ◽  
Author(s):  
E. A. Lapchenko ◽  
S. P. Isakova ◽  
T. N. Bobrova ◽  
L. A. Kolpakova

It is shown that the application of the Internet technologies is relevant in the selection of crop production technologies and the formation of a rational composition of the machine-and-tractor fl eet taking into account the conditions and production resources of a particular agricultural enterprise. The work gives a short description of the web applications, namely “ExactFarming”, “Agrivi” and “AgCommand” that provide a possibility to select technologies and technical means of soil treatment, and their functions. “ExactFarming” allows to collect and store information about temperature, precipitation and weather forecast in certain areas, keep records of information about crops and make technological maps using expert templates. “Agrivi” allows to store and provide access to weather information in the fi elds with certain crops. It has algorithms to detect and make warnings about risks related to diseases and pests, as well as provides economic calculations of crop profi tability and crop planning. “AgCommand” allows to track the position of machinery and equipment in the fi elds and provides data on the weather situation in order to plan the use of agricultural machinery in the fi elds. The web applications presented hereabove do not show relation between the technologies applied and agro-climatic features of the farm location zone. They do not take into account the phytosanitary conditions in the previous years, or the relief and contour of the fi elds while drawing up technological maps or selecting the machine-and-tractor fl eet. Siberian Physical-Technical Institute of Agrarian Problems of Siberian Federal Scientifi c Center of AgroBioTechnologies of the Russian Academy of Sciences developed a software complex PIKAT for supporting machine agrotechnologies for production of spring wheat grain at an agricultural enterprise, on the basis of which there is a plan to develop a web application that will consider all the main factors limiting the yield of cultivated crops.


Author(s):  
Tamara A. Novikova ◽  
Aleksey N. Danilov ◽  
Vladimir F. Spirin

Introduction. T e leading place in the structure of occupational morbidity of agricultural machine operators is occupied by vertebroneurological diseases, the development of which can be associated with the impact of ergonomic factors of labor activity. T e aim of the study is to assess the ergonomic factors of working conditions on mobile agricultural machinery and to identify their impact on the formation of health disorders of agricultural machine operators. Materials and methods. Complex physiological and ergonomic researches at operation of tractors and combine harvesters of old samples of domestic production including an assessment of the organization of workplaces on compliance to requirements of ergonomics and anthropometric data of workers, temporary, statodynamic, biomechanical characteristics of working poses and movements, a functional condition of machine operators (130 people aged 20–45 years with professional experience of work not less than three years) in dynamics of a work shift are carried out. Anthropometric studies were conducted among male machine operators (663 people) aged 18–59 years and with experience in the profession for more than three years. Results. The discrepancy between the size and space-layout parameters of workplaces ergonomic requirements and anthropometric data of machine operators, causing the formation of uncomfortable working positions, increasing physical activity and the severity of the labor process. A high degree of correlation between changes in the parameters of the neuromuscular system and the severity of the discrepancy between the ergonomic parameters of anthropometric characteristics of machine operators (r=0,7). T e results of the research allowed to determine the priority measures for the prevention of vertebroneurological diseases in agricultural machine operators. Conclusions. T e organization of workplaces on domestic tractors and combine harvesters of old samples does not meet the ergonomic requirements and anthropometric data of machine operators, which is the reason for the formation of an uncomfortable working posture, increased statodynamic physical activity, early development of fatigue and fatigue in the process, which can cause the development of pathological conditions of the spine and ligamentous apparatus. Ergonomic improvement of workplaces is one of the priority measures to preserve the health of agricultural machine operators.


2019 ◽  
Vol 8 ◽  
pp. 54-56
Author(s):  
Ashmita Dahal Chhetri

Advertisements have been used for many years to influence the buying behaviors of the consumers. Advertisements are helpful in creating the awareness and perception among the customers of a product. This particular research was conducted on the 100 young male and female who use different brands of product to check the influence of advertisement on their buying behavior while creating the awareness and building the perceptions. Correlation, regression and other statistical tools were used to identify the relationship between these variables. The results revealed that the relationship between media and consumer behavior is positive. The adve1tising impact on sales and there is positive and high degree relationship between advertising and consumer behavior. The impact on advertising of a product of electronic media is better than non-electronic media.


2020 ◽  
Vol 41 (5) ◽  
pp. 604-607 ◽  
Author(s):  
Mark D. Lesher ◽  
Cory M. Hale ◽  
Dona S. S. Wijetunge ◽  
Matt R. England ◽  
Debra S. Myers ◽  
...  

AbstractWe characterized the impact of removal of the ESBL designation from microbiology reports on inpatient antibiotic prescribing. Definitive prescribing of carbapenems decreased from 48.4% to 16.1% (P = .01) and β-lactam–β-lactamase inhibitor combination increased from 19.4% to 61.3% (P = .002). Our findings confirm the importance of collaboration between microbiology and antimicrobial stewardship programs.


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