Journal of Nature, Science & Technology (JANSET)

Ivane Tsagareli Bakur Gulua

The construction of solutions in explicit form is especially important from the point of view of its application, since it makes it possible to effectively carry out a quantitative analysis of the problem under study. This paper investigates the processes of deformation of solids in the quasi-static case. Two-dimensional boundary value problems of Dirichlet and Neumann for an elastic body with double porosity are considered. In Using the Laplace transform, these problems are reduced to auxiliary boundary value problems. Special representations of solutions to auxiliary boundary value problems are constructed using elementary functions that allow reducing the original system of equations to equations of a simple structure and facilitate the solution of the original problems. Auxiliary boundary value problems are solved for a specific elastic body - a porous disk. Solutions to these problems are obtained in the form of series. Conditions are provided that ensure the absolute and uniform convergence of these series and the use of the inverse Laplace theorem. It is proved that the inverse transforms provide a solution to the initial problems.

https://doi.org/10.36937/janset.2021.003.001

Yuriy Nikolaevich Zayko

The article is devoted to the construction of numerical systems, alternative to the system of real numbers and applicable in curvilinear space-time. Examples of such systems are given. Within the framework of a stationary numerical system, it is admissible to sum the diverging series like the Dirichlet series for the Riemann zeta function without resorting to its analytic continuation to the plane of the complex argument. In the framework of a non-stationary numerical system, a description of the Hubble effect is obtained, taking into account the corrections that correspond to the apparently accelerated recession of galaxies without invoking the hypothesis of dark energy

https://doi.org/10.36937/janset.2021.003.002

Lamara Bitsadze

This paper studies the linear theory of thermoelastic materials with inner structure whose particles,in addition to the classical displacement and temperature fields, possess microtemperatures. The present work considers the 2D equilibrium theory of thermoelasticity for solids with microtemperatures. This paper is devoted to the explicit solution of the Neumann type boundary value problem for an elastic plane, with microtemperatures having a circular hole. Special representations of the regular solutions of the considered equations are constructed by means of the elementary (harmonic, bi-harmonic and meta-harmonic) functions. Using the Fourier method, we presented the solution of the Neumann type boundary value problem for the plane with circular hole in the explicit form.

https://doi.org/10.36937/janset.2021.003.003

Micah Omare Joshua Kiprotich Kibet Jackson K. Cherutoi Fredrick O. Kengara

Herein, we present phenolic reaction products from the thermolysis of khat that is remarkable in the context of smoked khat under conditions that are representative of cigarette smoking. Phenolic compounds occur naturally and some as a result of continuous human activities yielding grave environmental and human health risks. Accordingly, this study investigates the phenolic compounds generated from the thermal degradation of Catha edulis, computes the global energies and entropies of selected phenolic compounds and their derivatives, and performs their geometry optimization using Gaussian computational package. In addition, we report on the elemental speciation of char from khat pyrolysis. The thermal degradation of khat was conducted in an inert nitrogen environment at 1 atmosphere at a contact time of 2s using a quartz tubular reactor. The pyrolysis effluent was characterized using a Gas-chromatograph coupled to a mass spectrometer. The GC-MS results indicated that the khat pyrolysis yielded phenolic compounds including p-cresol, catechol, hydroquinone and other substituted methoxy phenols whose maximum release was attained at temperatures of 450 °C and 550 °C. During khat pyrolysis, phenols displayed an increase in reaction endothermicity with increase in temperature up to temperatures of around 400 °C after which reaction exothermicity is witnessed. It is evident that toxic phenolic compounds are predominantly released from khat pyrolysis and are likely to cause devastating effects in human beings once ingested. Accordingly, campaigns against the smoking of khat should be carried out in efforts to promoting health living standards amongst human beings.

https://doi.org/10.36937/janset.2021.003.004

Md. Belal Hossain Md. Rashedul Haque Md. Mahabub Rahman

In seismic analysis, shear wave velocity ("V" _"s" ) is a valuable parameter for measuring the site effect of earthquake microzonation. Various methods have been explored to measure this key factor directly. Since measuring shear wave velocity directly is time consuming and expensive, researchers in various regions have been attempting to update empirical relationships between shear wave velocity ("V" _"s" ) and other soil geotechnical properties such as SPT blow count, depth, vertical effective stress and so on. Geophysical tests associated with direct methods are not feasible in developing countries like Bangladesh, so the indirect method is more important. Due to the location of a fault line nearby, the Dinajpur district has previously undergone anomalous earthquakes. As a result, site characterization is important for enhancing seismic design considerations. Focused on an indirect approach, this paper mainly aims to propose a general correlation between shear wave velocity and standard penetration number in 13 upazilas of Dinajpur district for four soil categories (“all soils”, sand, clay, and silt). Finally, an approach was developed to find the overall correlations for the Dinajpur district by combining all of the data. The regression coefficient ("R" ^"2" ) values were observed to vary in between 0.04416-0.6134 for “all soils”, 0.0593-0.668 for sand, 0.5911-0.7149 for clay and 0.5547-0.6794 for silt. The correlations obtained in this study can be used for seismic hazard analysis in both the study region and other areas with identical soil strata.

https://doi.org/10.36937/janset.2021.003.005