Life cycle assessment of technical systems taking into consideration degradation processes in materials of constructions

2018 ◽  
Vol 1 (89) ◽  
pp. 5-8 ◽  
Author(s):  
Z. Stotsko ◽  
M. Kuzin

Purpose: In the engineering analysis and transport forensic examination, there are often arise problems in establishing the causes and mechanism for the destruction of structural elements. At the moment, such problems are poorly formalized and practically do not take into account the degradation of the material and the gradient of its properties when destroyed. The purpose of this article was to build a methodology for determining the distribution of material properties at the initial time and establishing its compliance with the requirements of regulatory documentation. Design/methodology/approach: As a technique for solving the problem, was proposed the expansion of a function in a given basis with subsequent refinement of the solution using iterative algorithmic schemes. Findings: Using the developed approaches, it is established that in the surface layers of 12X18H10T steel (AISI 321), after technological modification under the conditions of laser doping, functional-gradient layers are formed with the material viscosity level characteristics at 0.8, which corresponds to the established norms, and their destruction occurred as a result of excessive loads. Practical implications: With the using of the developed methods makes it possible to solve the problem of technical forensic examination to determine compliance to the requirements the properties of functional gradient materials in initial time. Originality/value: The technique of solving inverse problems of fracture mechanics for functional gradient materials is shown for the first time.

Author(s):  
Elena Mikhaylovna Chervonenko ◽  
Lina Yurievna Lagutkina

The article describes the process of tench growing (male and female species removed from set gear in the Volga river in the Astrakhan region) using experimental feedstuff "T", taking into account the fact that problems with artificial growing tench ( Тinca tinca ) appear first in the process of feeding when wild sires change to artificial food. The research took place on the base of the department of aquaculture and water bioresources of Astrakhan State Technical University in innovation centre "Bioaquapark - scientific and technical centre of aquaculture" in 2015. Special feed including components of animal origin - mosquito grab and sludge worm as an effective substitute to fish flour, as well as components of vegetable origin (carrot, parsley, pumpkin, wheatgrass) for domestication of tenches are offered for the first time. Food technology has been described. The exact composition of the formula, which is being licensed at the moment, is not disclosed. Feed "T", which has undergone biological analysis and is in accordance with organoleptic and physical standards was used for feeding tench female and male species during domestication period (60 days), along with food "Coppens" (Holland). Feed efficiency was determined according to survival and daily fish growth. Growth rate of females appeared more intensive than growth rate of males fed with experimental food "T". Daily growth changed depending on the types of food: from 0.3 ("Coppens") to 0.47 (experimental food) in females, from 0.25 ("Coppens") to 0.39 (experimental food) with males. Ability to survive among tench species fed with "Coppens" and experimental food made 60% and 100%, correspondingly. Nutricion of tench species with experimental food encouraged their domestication, which allowed using tench species in further fish breeding process in order to get offspring. The project was supported by the Innovation Promotion Fund in terms of the project "Development and implementation of the technique for the steady development of aquaculture: food "TechSA".


Author(s):  
Elizabeth Shannon

Study abroad begins long before students leave their own shores. The moment that children enter daycare, nursery school, or kindergarten for the first time, they are in foreign territory, and all their antennae are out, testing, absorbing, learning. They begin to develop the first of their many multiple identities. They are no longer "Johnny" or "Sarah" whom everyone knows and loves at home, but Johnny or Sarah whom no one knows nor initially cares about, and they have to figure out what kind of a new identity they will develop so the danger zone becomes as safe as home.  Leaving familiar surroundings- the sounds, smells, safety, and food of home- and realizing, quite abruptly, that they must learn to adapt to the demands and needs of strangers, is the first and the most challenging "trip abroad" they will ever take. They will use the same set of skills, more mature, more polished (we hope) when they arrive on a foreign campus and move in with a host family or into an international dormitory.  Learning to make the journey with ease, whether it is on the first day of school or the day a plane drops one in a foreign field, is a necessary accomplishment. We have to make friends out of our peers; we have to gain the respect of our teachers; we have to develop curiosity and concern about the people around us. The stranger they seem, the more there is to learn. To fear diversity is to fear life itself. As the world becomes smaller and more integrated, the more crucial this accomplishment grows. 


Mathematics ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 868
Author(s):  
Khrystyna Prysyazhnyk ◽  
Iryna Bazylevych ◽  
Ludmila Mitkova ◽  
Iryna Ivanochko

The homogeneous branching process with migration and continuous time is considered. We investigated the distribution of the period-life τ, i.e., the length of the time interval between the moment when the process is initiated by a positive number of particles and the moment when there are no individuals in the population for the first time. The probability generating function of the random process, which describes the behavior of the process within the period-life, was obtained. The boundary theorem for the period-life of the subcritical or critical branching process with migration was found.


Author(s):  
László Holló

"In less than one year, the Catholic Church, just like the other denominations, lost its school network built along the centuries. This was the moment when the bishop wrote: “No one can resent if we shed tears over the loss of our schools and educational institutions”. Moreover, he stated that he would do everything to re-store the injustice since they could not resent if we used all the legal possibilities and instruments to retrieve our schools that we were illegally dispossessed of. Furthermore, he evaluated the situation realistically and warned the families to be more responsible. He emphasized the parents’ responsibility. First and foremost, the mother was the child’s first teacher of religion. She taught him the first prayers; he heard about God, Jesus, the Virgin Mary, and the angels from his mother for the first time. He asked for the mothers’ and the parents’ support also in mastering the teachings of the faith. Earlier, he already instructed the priests to organize extramu-ral biblical classes for the children and youth. At this point, he asked the families to cooperate effectively, especially to lead an ardent, exemplary religious life, so that the children would grow up in a religious and moral life according to God’s will, learn-ing from the parents’ examples. And just as on many other occasions throughout history, the Catholic Church started building again. It did not build spectacular-looking churches and schools but rather modest catechism halls to bring communities together. These were the places where the priests of the dioceses led by the bishop’s example and assuming all the persecutions, incessantly educated the school children to the love of God and of their brethren, and the children even more zealously attended the catechism classes, ignoring their teachers’ prohibitions. Keywords: Márton Áron, Diocese of Transylvania, confessional religious education, communism, nationalization of catholic schools, Catholic Church in Romania in 1948."


2018 ◽  
Vol 37 (6) ◽  
pp. 545-550
Author(s):  
Mikhail Isupov ◽  
Vadim Pinaev ◽  
Daria Mul ◽  
Natalia Belousova

AbstractAn experimental investigation of plasma-assisted nitriding of austenitic stainless steel AISI 321 in a low-pressure (7 Pa), low-frequency (50–100 kHz) nitrogen inductively coupled plasma enhanced with ferromagnetic cores has been performed at the temperatures of 470–625 °C, sample biases of ‒500–‒750 V, current densities on the sample surface of 1.2–3.3 mA/cm2 and nitriding times of 20 and 60 min. It is found that even the short (20 min) ion-plasma treatment results in the formation of nitrided layers with the thickness of up to 40 μm and microhardness of up to 9 GPa.The high speed of nitriding can be explained as a result of the joint action of high ion flux density and high ion energy on the sample surface.


2018 ◽  
Author(s):  
E. I. Senaeva ◽  
A. V. Makarov ◽  
N. B. Pugacheva ◽  
E. B. Trushina

Kavkaz-forum ◽  
2021 ◽  
pp. 90-100
Author(s):  
Ф.С. Киреев

В статье анализируются причины возвращения войсковой системы самоуправления Терского казачества и показан сам процесс создания выборности войсковой власти. Актуальность исследования казачьего самоуправления обусловлена необходимостью теоретического обоснования и практического осуществления самоорганизации казачества России. Исторический анализ процесса организации самоуправления Терского казачества на войсковом уровне может послужить фундаментом для лучшего понимания и оценки современных процессов и явлений в казачьей среде и поможет выстраиванию государственной политики в отношении казачества в современной России. В отечественной историографии отсутствуют работы, посвященные конкретно восстановлению выборности власти в Терском казачьем войске. Поэтому научная новизна исследования определяется тем, что впервые предпринята попытка хронологической реконструкции истории создания войсковой системы самоуправления Терского казачества. Методологической основой исследования является принцип историзма, что предусматривает изучение момента возникновения исторического события и этапы его развития. Анализ событий на Тереке в 1917 г. показывает, что терские казаки смогли самоорганизоваться, создать полноценное административно-территориальное образование, и лишь изменение социально-политической ситуации в России в целомпомешало укрепить и продолжить это начинание. Еще необходимо отметить, что терские казаки к моменту восстановления войскового самоуправления подошли уже с готовыми проектами соответствующих документов, что позволило Терскому войску первым среди других войск создать свою выборную власть. Это говорит о высоком интеллектуальном потенциале в среде терских казаков. The article analyzes the reasons for the restoration of the military system of self-government of the Terek Cossacks and shows the very process of creating the elective military power. The relevance of the study of Cossack self-government is due to the need for theoretical justification and practical implementation of the self-organization of the Cossacks of Russia. Historical analysis of the process of organizing self-government of the Terek Cossacks at the military level can serve as a foundation for better understanding and assessment of modern processes and phenomena in the Cossack environment and will help to build state policy towards the Cossacks in modern Russia. In the Russian historiography, there are no works devoted specifically to the restoration of the election of power in the Terek Cossack army. Therefore, the scientific novelty of the research is determined by the fact that for the first time an attempt was made to chronologically reconstruct the history of the creation of the military system of self-government of the Terek Cossacks. The methodological basis of the research is the principle of historicism, with its focus on the study of the moment of occurrence of a historical event and the stages of its development. An analysis of the events on the Terek in 1917 shows that the Terek Cossacks were able to organize themselves and create a full-fledged administrative-territorial entity and only a change in the socio-political situation in Russia as a whole was placed, strengthened and continued this initiative. It should also be noted that the Terek Cossacks, by the time of the restoration of military self-government, came up with ready-made drafts of relevant documents, which allowed the Terek army to be the first among other troops to create their own elected power. This indicates a high intellectual potential among the Terek cossacks.


2020 ◽  
Vol 16 (1) ◽  
pp. 13-23
Author(s):  
M. Lefebvre

AbstractLet X(t) be a jump-diffusion process whose continuous part is a Wiener process, and let T (x) be the first time it leaves the interval (0,b), where x = X(0). The jumps are negative and their sizes depend on the value of X(t). Moreover there can be a jump from X(t) to 0. We transform the integro-differential equation satisfied by the probability p(x) := P[X(T (x)) = 0] into an ordinary differential equation and we solve this equation explicitly in particular cases. We are also interested in the moment-generating function of T (x).


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