Mathematical modeling and test verification of viscoelastic materials considering microstructures and ambient temperature influence

Background: The constancy of the ambient temperature is the main condition to correctly determine the time of death by thermometric method. However, in practice, this requirement is met only in cases of death in closed rooms. In this study, an exponential mathematical model was proposed for corpse cooling under any changes in ambient temperature. Aim: This study aimed to develop a mathematical model to determine the time of death based on the NewtonRichman cooling law in changing ambient temperature conditions. Materials and methods: Mathematical modeling of corpse cooling under changing ambient temperature is performed, focusing on problem solving of thermometric determination of the time of death. The axillary hollow was used as the diagnostic zone of the corpse, and the temperature of which at the time of death is taken is 36.6С. Results: A method of reverse reproduction of the cadaver temperature in conditions of changing ambient temperature has been developed. Results allow a relatively simple analytical determination of the time of death in the early postmortem period. Conclusions: The proposed method is advisable to be used in forensic medical practice to determine the time of death in early postmortem period. The developed mathematical model is implemented in the format of the application program Warm Bodies NRN. Use of tympanic and intraocular thermometry was recommended within the proposed model.

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INFLUENCE OF DYNAMIC LOADING ON THE CHARACTERISTICS OF POLYMER IMPACT DAMPERS

PROBLEMS OF APPLIED MECHANICS ◽

10.30987/conferencearticle_5fd1ed035dbc84.89285592 ◽

2020 ◽

Author(s):

Vladimir Altuhov ◽

Aleksey Boldyrev ◽

Pavel Zhirov

Keyword(s):

Mathematical Modeling ◽

Mathematical Model ◽

Ambient Temperature ◽

Dynamic Loading ◽

Loading Rate ◽

Rolling Stock ◽

Wear Factor ◽

Shock Absorbers ◽

Draft Gear ◽

Freight Car

The article is devoted to the study of the influence of dynamic loading on the characteristics of polymer elements of shock absorbers of the rolling stock of railways and to the description of the creation of a mathematical model of their work. The results of mathematical modeling are further used to solve problems of the longitudinal dynamics of rolling stock. In the study, the initial loading rate varied, the ambient temperature and the influence of the wear factor remained unchanged. For the operating speeds of a freight car, a mathematical model of the PMKP-110 draft gear was determined.

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Ambient temperature influence on catalytic outlet—inlet temperature difference

Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering ◽

10.1243/0954407001527259 ◽

2000 ◽

Vol 214 (1) ◽

pp. 95-100 ◽

Cited By ~ 3

Author(s):

P. N. Botsaris ◽

P. D. Sparis

Keyword(s):

Ambient Temperature ◽

Temperature Difference ◽

Inlet Temperature ◽

Temperature Influence

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MATHEMATICAL MODELING OF RESIDUAL STRESSES IN PLASMA COATINGS TAKING INTO ACCOUNT THE PROCESS OF INCREASING LAYERS

Izvestiya of Samara Scientific Center of the Russian Academy of Sciences ◽

10.37313/1990-5378-2020-22-6-14-20 ◽

2020 ◽

Vol 22 (6) ◽

pp. 14-20

Author(s):

V.I. Bogdanovich ◽

◽

M.G. Giorbelidze ◽

I.A. Dokukina ◽

N.V. Surkova ◽

...

Keyword(s):

Mathematical Modeling ◽

Mathematical Model ◽

Residual Stresses ◽

Mathematical Models ◽

Ambient Temperature ◽

Experimental Studies ◽

Final Temperature ◽

Good Convergence ◽

Plasma Coatings

Developed a mathematical model for determining residual stresses with increasing plasma coatings, taking into account the stresses arising upon cooling of the material from the final temperature to ambient temperature; tension that arises when removing the fastening devices and tension that existed in the substrate before spraying. The developed mathematical models are adapted for the most common cases of fixing the base used in the practice of coating. Experimental studies of residual stresses were carried out, which showed good convergence with the values of residual stresses obtained theoretically.

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MATHEMATICAL MODELING OF ERRORS IN DETERMINING THE TIME OF DEATH ON THE BASIS OF THE NEWTON’S - RICHMAN’S COOLING LAW

Russian Journal of Forensic Medicine ◽

10.17816/fm373 ◽

2021 ◽

Author(s):

G. Nedugov

Keyword(s):

Mathematical Modeling ◽

Mathematical Model ◽

Ambient Temperature ◽

Measurement Model ◽

Indirect Measurement ◽

Analytical Determination ◽

Thermal Method ◽

Time Of Death ◽

Maximum Absolute Errors ◽

Diagnostic Technologies

Abstract. A mandatory element of the development and implementation of diagnostic technologies for determining the time of death by the thermal method is the assessment of their possible errors. For equations of cadaver cooling that have a deterministic character, the estimation of errors is possible on the basis of a mathematical model of indirect measurement. In this article, a mathematical model is proposed for estimating the maximum absolute errors in determining the prescription of death on the basis of the Newtons - Richmans cooling law under conditions of constant and changing ambient temperature. Aim. To develop, on the basis of a mathematical model of indirect measurement, a method for estimating errors in determining the prescription of death on the basis of the Newtons - Richmans cooling law. Material and methods. Mathematical modeling of errors in determining the time of death in conditions of constant and changing ambient temperature is carried out on the basis of the Newtons - Richmans law. The computer program code is written in the C# programming language using the Microsoft Visual Studio 2019 application. Results. On the basis of the indirect measurement model, a method for estimating the maximum absolute errors in determining the time of death during cooling according to the Newtons - Richmans law under conditions of constant and changing ambient temperature is developed. The results obtained allow us to carry out an analytical determination of the errors in time the prescription of death in the early postmortem period. Conclusions. A mathematical model is developed for estimating the maximum absolute errors in determining the time of death on the basis of the Newtons - Richmans cooling law under conditions of constant and changing ambient temperature. The developed mathematical model is implemented in the format of the application program Warm Bodies NRN. The proposed method is advisable to use in forensic medical expert practice in determining the time of death.

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