Water movement in melting snow

The mathematical model of water movement in melting snow is studied in neglect of deformation of the porous medium. As the mathematical model of the problem, the mass conservation equations for water, air and stationary porous skeleton of snow are used along with an analogue of Darcy’s law for water and air. Water and air are considered to be individual phases with its own filtration rate determined in solving the problem. This assumption allows constructing the closed model. The numerical test calculations are carried out. The mathematical model under study is verified using experimental data.

EXTENSION OF THE MINIMUM COST FLOW PROBLEM (MCFP OR CNF) BY CONSIDERATION OF TIME AND QUANTITY OF LOADS WITH MAXIMUM TIME

This paper extends the general problem of minimizing the total cost of transport on the road network (CNF) by considering the total time, maximum time and total amount of cargo with the longest time. In the literature available to us, models with timing and amount of cargo in the case of a standard transport task were exposed. Optimization is possible by combining 5 criteria, 2 linear and 3 nonlinear ones over the same set of linear constraints. Multicriteria optimization determines Pareto-optimal solutions. Interactive analyst-software algorithms for solving the selected models were defined. The solution of hypothetical problems was illustrated. Closed model with 5 two-way asymmetric communications using software for CNF and it is possible to use software for LP. Four one-criteria problems were solved: total costs, overall transport performance from a time standpoint, transport time (problem of the second type by time) total transport time (problem of the third type by time) and one bi-criteria problem related to the simultaneous minimization of the maximum duration of transport and total costs.

Software Quality Model in the Presence of Culture Quality Factors

Researchers have often attempted to raise the success rate of software systems over the past century. Improve software quality models and other software elements to make it more customer satisfaction and achieve customer permanence. Several quality models and variables have been proposed to decrease software system failure and complexity. Also, several software quality models were proposed to assess the general and particular types of software products. These models have been proposed to determine the general or particular scopes of software products. The proposed models evaluate based on comparisons between the well-known models to customize the closed model. These comparisons are the leakage of criteria based on distinct views and knowledge of cultural and social requirements. A new factors proposed by the customize software quality models. The proposed cultural model has eight criterions namely: Language, Religion, social habits, publishing, custom, Ethics, and Law. We classified the new criterions factors into three main groups. The outcome of the proposed cultural model demonstrates that the eight criterions factors must be deemed to decrease the satisfactions of software failure and permanence variables. Finally we proposed a cultural language metric for measuring the satisfactions of software failure and permanence variables.

Research of the radial-axial turbine of the marine diesel engine impulse turbocharging system

В статье представлены результаты исследований радиально-осевой турбины, работающей в составе импульсной системы наддува среднеоборотного судового дизеля. Исследования носили теоретический и экспериментальный характер и базировались на предлагаемом методе проектирования и расчета, который комбинируя на определенных этапах модели расчета радиально-осевой турбины, а также замкнутую модель рабочего процесса комбинированного двигателя, позволяет решать задачи проектирования проточных частей турбины для работы в нестационарном потоке импульсной системы наддува. Целью исследований является отработка основных положений предлагаемого метода проектирования радиально-осевой турбины, работающей в составе импульсной системы наддува комбинированного двигателя, на примере поиска оптимальных параметров радиально-осевой турбины турбокомпрессора среднеоборотного судового дизеля размерности 18/22. В работе получена модернизированная геометрия проточной части турбины. Представлены результаты экспериментальных и расчетных исследований характеристик модернизированной и штатной турбин, подтверждающие повышение эффективности модернизированной турбины во всем диапазоне ее характеристики. Представлены результаты испытаний судового дизеля 6ЧН 18/22 с модернизированной и штатной турбинами по нагрузочной характеристике, показывающие положительное влияние измененной геометрии турбины на эффективные показатели дизеля и подтверждающие возможность использования предлагаемого метода проектирования радиально-осевой турбины системы наддува комбинированного двигателя. The article presents the results of research on a radial-axial turbine operating as part of a pulsed boost system for a medium-speed marine diesel engine. The research was theoretical and experimental in nature and was based on the proposed design and calculation method, which combines at certain stages of the radial-axial turbine calculation model, as well as a closed model of the combined engine workflow, allows you to solve the problems of designing the flow parts of the turbine for operation in a non-stationary flow of a pulse boost system. The aim of the research is to develop basic provisions of the proposed design method of the radial-axial turbine, which is part of pulse systems boost engine combined, for example, finding the optimal parameters of the radial-axial turbine of the turbocharger, the medium-speed marine diesel dimensions 18/22. The upgraded geometry of the flow part of the turbine is obtained. The results of experimental and computational studies of the characteristics of upgraded and standard turbines are presented, confirming the increase in the efficiency of the upgraded turbine over the entire range of its characteristics. The results of tests of the 6ChN 18/22 marine diesel engine with upgraded and standard turbines on load characteristics are presented, showing the positive effect of the changed turbine geometry on the effective performance of the diesel engine and confirming the possibility of using the proposed method of designing a radial-axial turbine of the combined engine supercharging system.

Effect of a Slat Arm Door on the Wing Efficiency of a Commercial Aircraft.

The objective of this thesis is to determine the influence of a slat arm door on the aerodynamic performance of a wing of a commercial aircraft during it's take off and landing configurations using CFD simulation. The slats are extended forward by extendable arms coming out from the leading edge of the wing after the slat arm is deployed. CFD analysis of wing and slat configuration of the aircraft showed that the removal of this slat door at higher angle of attacks increased the drag by 0.88%, reduced the lift by 1.29%, increased the inert particle residence time inside the slat door compartment by 200.00% and increased the local flow separation area on the top surface of the wing by 42.81% with reference to the closed model.

Effect of a Slat Arm Door on the Wing Efficiency of a Commercial Aircraft.

The objective of this thesis is to determine the influence of a slat arm door on the aerodynamic performance of a wing of a commercial aircraft during it's take off and landing configurations using CFD simulation. The slats are extended forward by extendable arms coming out from the leading edge of the wing after the slat arm is deployed. CFD analysis of wing and slat configuration of the aircraft showed that the removal of this slat door at higher angle of attacks increased the drag by 0.88%, reduced the lift by 1.29%, increased the inert particle residence time inside the slat door compartment by 200.00% and increased the local flow separation area on the top surface of the wing by 42.81% with reference to the closed model.

The Tipping Effect of Delayed Interventions on the Evolution of COVID-19 Incidence

We combine infectious disease transmission and the non-pharmaceutical intervention response to disease incidence into one closed model consisting of two coupled delay differential equations for the incidence rate and the time-dependent reproduction number. The model contains three parameters, the initial reproduction number, the intervention strength, and the response delay. The response is modeled by assuming that the rate of change of the reproduction number is proportional to the negative deviation of the incidence rate from an intervention threshold. This delay dynamical system exhibits damped oscillations in one part of the parameter space, and growing oscillations in another, and these are separated by a surface where the solution is a strictly periodic nonlinear oscillation. For the COVID-19 pandemic, the tipping transition from damped to growing oscillations occurs for response delays of about one week, and suggests that, without vaccination, effective control and mitigation of successive epidemic waves cannot be achieved unless NPIs are implemented in a precautionary manner, rather as a response to the present incidence rate. Vaccination increases the quiet intervals between waves, but with delayed response, future flare-ups can only be prevented by establishing a post-pandemic normal with lower basic reproduction number.

Methodological approaches to the formation of management innovation processes of industrial enterprises

The economic activity of an organization includes many aspects of innovative management, which largely determines the success of its functioning. Based on the accumulated research base and analysis of the activities and structure of enterprises, the authors propose several types of classification of enterprise functioning models. According to the criterion of the behavioral model, the authors divide organizations into organizations that act according to the conjunctural algorithm, focus on marketing principles and the so-called organizations of technological breakthrough, describe the main properties of these models and the differences in the behavior of enterprises of different groups from each other. The formation of managerial innovation processes is associated not only with their behavioral model, but also with the degree of influence of external factors on the company's activities. According to this principle, organizations belong to either an open or closed model. Closed models, in turn, are divided into those that function on the basis of theoretical postulates of scientific management and focus on the aspect of internal social interaction. Open models include enterprises that organize their economic activities based on the results of analysis according to the concept of systems theory and enterprises that resemble public institutions in their form and activity.

An essential base of the central types of the convex theory

In this paper, we consider the model-theoretical properties of the essential base of the central types of convex theory. Also shows the connection between the center and Jonsson theory in permissible enrichment signatures. Moreover, the theories under consideration are hereditary. This article is divided into 2 sections: 1) an essential types and an essential base of central types (in this case, the concepts of an essential type and an essential base are defined using the Rudin-Keisler order on the set of central types of some hereditary Jonsson theory in the permissible enrichment); 2) the atomicity and the primeness of ϕ(x)-sets. In this paper, new concepts are introduced: the ϕ(x)-Jonsson set, the AP A-set, the AP A-existentially closed model, the ϕ(x)-convex theory, the ϕ(x)-transcendental theory, the AP A-transcendental theory. One of the ideas of this article refers to the fact that in the work of Mustafin T.G. it was noticed that any universal model of a quasi-transcendental theory with a strong base is saturated, but we generalized this result taking into account that: the concept of quasi-transcendence will be replaced by the ϕ(x)-transcendence, where ϕ(x) defines some Jonsson set; and the notion of a strong base is replaced by the notion of an essential base, but in a permissible enrichment of the hereditary Jonsson theory. The main result of our work shows that the number of fragments obtained under a closure of an algebraic or definable type does not exceed the number of homogeneous models of a some Jonsson theory, which is obtained as a result of a permissible enrichment of the hereditary Jonsson theory.