26 research outputs found

    A new approach for solving nonlinear Thomas-Fermi equation based on fractional order of rational Bessel functions

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    In this paper, the fractional order of rational Bessel functions collocation method (FRBC) to solve Thomas-Fermi equation which is defined in the semi-infinite domain and has singularity at x=0x = 0 and its boundary condition occurs at infinity, have been introduced. We solve the problem on semi-infinite domain without any domain truncation or transformation of the domain of the problem to a finite domain. This approach at first, obtains a sequence of linear differential equations by using the quasilinearization method (QLM), then at each iteration solves it by FRBC method. To illustrate the reliability of this work, we compare the numerical results of the present method with some well-known results in other to show that the new method is accurate, efficient and applicable

    Shifted Boubaker Lagrangian approach for solving biological systems

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    Mathematical models and computer simulations are useful experimental tools for building and testing theories. Many mathematical models in biology can be formulated by a nonlinear system of ordinary differential equations. This work deals with the numerical solution of the hantavirus infection model, the human immunodeficiency virus (HIV) infection model of CD4+T cells and the susceptible-infected-removed (SIR) epidemic model using a new reliable algorithm based on shifted Boubaker Lagrangian (SBL) method. This method reduces the solution of such system to a system of linear or nonlinear algebraic equations which are solved using the Newton iteration method. The obtained results of the proposed method show highly accurate and valid for an arbitrary finite interval. Also, those are compared with fourth-order Runge-Kutta (RK4) method and with the solutions obtained by some other methods in the literature. © 2018 World Scientific Publishing Company

    Study of Effectiveness of Human Factors Engineering Interference in Cumulative Trauma Disorders Rate Decreasing in the Tehran South Health Center 2005-2006

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    Introduction: Up to now accomplished many investigations about cumulative trauma disorders (CTD) accession. For the most part sitting pattern and unsuitable task posture has been specified reason of these complications. In the publicized stats from a foreign source ambit of 44 percent of people who worked with computer has been afflict to the CTD's. The aim of this paper is to find and measurement of CTD and ergonomic intervention and investigation rate of this intervention's effect in the Tehran south health center. This center use paperless system. Methods: In this research Nordic questionnaire distribute between 68 persons of the center to determine CTD's. By technical expert inspection specified reason of complications. Observantly to state methods reason which create more severity and frequency CTD's has been recognized and interference with human factors engineering. For the more efficiency of interference Anthropometry has been used for all of Work stations and for any person designed a significant posture. Results: results that obtained before interference indicate that were CTD's complications at more of employees which 90 percent of them suffered of up spine pain. Also 27.4 percent of them had shoulder pain and 20.4 percent had neck pain. After the interference these measures decreased. And complaint of employee decreased 40.8 percent to up spine pain. Also for the shoulder pain it reached to 22 and neck pain 17.6 percent. With state test identified that there are significant difference between CTD after and before of intervention (p<0.005). Conclusion: Being unsuitable task posture is main cause of CTD's in the Work stations. We can prevent to increasing these complications in the work place by simple approach like adjustment in the desk and chair height, correct performance working training and doing simple exercise

    Shifted Boubaker Lagrangian approach for solving biological systems

    No full text
    Mathematical models and computer simulations are useful experimental tools for building and testing theories. Many mathematical models in biology can be formulated by a nonlinear system of ordinary differential equations. This work deals with the numerical solution of the hantavirus infection model, the human immunodeficiency virus (HIV) infection model of CD4+T cells and the susceptible-infected-removed (SIR) epidemic model using a new reliable algorithm based on shifted Boubaker Lagrangian (SBL) method. This method reduces the solution of such system to a system of linear or nonlinear algebraic equations which are solved using the Newton iteration method. The obtained results of the proposed method show highly accurate and valid for an arbitrary finite interval. Also, those are compared with fourth-order Runge-Kutta (RK4) method and with the solutions obtained by some other methods in the literature. © 2018 World Scientific Publishing Company

    Studying the Environmental Health Status and Consumption of Baking Soda in Military and Urban Lavash Bakeries of Tehran in 2012

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    Background and purpose:Consumption of baking soda, as a primary material for preparation of bread dough, has been banned due to its health complications in Iran. So bread production in our country faced difficulties and one part of them is related to health issues which are bread production. Also, in some cases, baking soda is used in the bread production. This study was done to study the environmental health status and consumption of baking soda in the military and urban Lavash bakeries of Tehran in 2012. Materials and methods:This is a descriptive comparative study done on Lavash bread production of 14 military bakeries and 14 corresponding urban bakeries near them. PH in the samples was tested based on Institute of Standards and Industrial Research of Iran No. 2628. To check the status of environmental health and personal hygiene of bakeries, the check list of Cereal Research Center was used. Results:In terms of environmental health status,28.6% military bakeries and7.1% urban bakeries were at good level. In terms of personal hygiene, all bakeries were in the poor category. Also,42.9% of military Lavash bakeries and 14.3% of urban Lavash bakeries used baking soda in their bread production. Conclusion:Environment health and personal hygiene status in military bakeries are better than the urban bakeries however, hygiene status was not desirable in military bakeries. Also, baking soda consumption in military bakeries was more common than the urban bakeries. According to the results of this study, control of health status and avoiding baking soda consumption in the bakeries are necessary
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