شهاب غلامی

The present research aimed to investigate the effective factors on the tendency of street-working children to substance retail sales in the western provinces of the country (Ilam and Kermanshah).

The method of this research was qualitative and of thematic analysis type. The statistical population of the present research consisted of scientific and executive experts and specialists from Faraja, the judiciary and welfare, experts in the field of social harm and drugs, and street-working children and their families. Among them, 30 people were selected using the purposeful sampling method. In-depth and semi-structured interviews were used to collect data. The data were analyzed in three stages of open, axial, and selective coding.

The results showed that the effective factors included two main dimensions of direct and contextual factors and 4 components of psychological, family, social, and economic factors. The re-examination of the findings from two focus groups consisting of some active participants led to the identification of 4 process patterns, including the poor immigrant family, the family with a work culture, the family with irresponsible parents, and the beggar family.

The research results show that this issue is a multi-dimensional abnormal social phenomenon, and considering its nature, its control requires the interaction and cooperation of various institutions, which should be controlled and managed with necessary coordination and focusing on cultural and social responses.

In this article, the study of the non-Fourier heat conduction in casting sand that is located inside a container under an instantaneous heat flux. According to inefficiencies of Fourier model to model the behavior of this problem due to differences in heat transfer between the phases and the ability of the models based on fractional calculus to model the anomalous behavior in different materials, in this paper, a model based on fractional calculus have been used. This model has recently entered the field of physics. Thermal properties, initial and boundary conditions of the problem is assumed to be known. The governing equations have been solved in a try and error algorithm to find the phase lag and fractional order using an implicit discretization method. The results show that neither the super-diffusion fractional model nor sub-diffusion fractional model can model the heat transfer in the sand. Based on the present results, it can observe also that in the initial moment, sub-diffusion conditions and after that super-diffusion conditions govern on the problem. Using simultaneously sub-diffusion and super-diffusion models, the numerical results are able to cover the experimental data for the temperature distribution within the container.

In this study، numerical solution of non-Fourier heat conduction is discussed by a fractional single phase lag model in an inhomogeneous hollow cylinder made of a functionally graded material. For this purpose، all material properties of the media are assumed to vary continuously according to a power-law formulation except the phase lag and fractional order considered as constants. It is assumed that the cylinder is one-dimensional، symmetric and without any heat source. The governing equation has been solved numerically in a try and error algorithm to find the phase lag and the fractional order using an implicit numerical method. In order to validate the results، the numerical solutions of the fractional single phase lag model and the dual phase lag model are compared to the results of semi-analytical dual-phase lag. In the following the influence of non-homogeneity parameters is studied on the maximum transient temperature and thermal wave transmission speed. The temperature distribution is investigated from wave creation instance to steady state thermal distribution. Finally، the effect of different time delays and fraction orders on the temperature distribution is investigated.

In this paper، contact boundary condition between two pieces of the processed meat at different temperatures (two pieces with cold and room temperatures)، that were suddenly in contact with each other in an inverse non-Fourier heat conduction problem was estimated. The direct problem was non-Fourier heat conduction that expressed with fractional single phase model and this problem involved only the piece of the processed meat in the room temperature. In this problem، it was assumed that governing equation، thermophysical properties and initial and boundary conditions were known and then it was solved numerically using the modified Mac-Cormack method. In the inverse problem، the estimation of the unknown contact boundary condition in the fractional non-Fourier model as a new work is done using the parameter estimation version of conjugate gradient method without/with adjoin problem that is one of the efficient deterministic methods in inverse analysis. In addition، in order to obtain the measured temperature of the inverse problem، a linear dual phase lag model validated with experimental data، was used. Finally، these two methods were compared to each other. Their results of these two methods showed the efficient estimation of the unknown contact boundary condition in fractional non-Fourier heat conduction.