فهرست مطالب محمدرضا قریب

Groundwater aquifers are the main source of water for billions of people living in arid and semi-arid regions. Major changes in rainfall, groundwater pumping and feeding, and severe soil erosion, floods, and droughts are among the most noticeable consequences of climate change. All this complicates the challenge of conserving groundwater resources for the foreseeable future. These scenarios highlight the need to rethink current strategies for groundwater studies. This paper deals with the application of finite elements in groundwater studies. This paper analyzed Web of Science data using Biblioshiny - a powerful bibliometric analysis tool based on R software. The study shows that the Quebec National University of Scientific Research and the Indian Institute of Technology are the most active research centers on the use of finite elements in groundwater studies, and China, America, Canada, Germany, Italy, France, Great Britain, and Iran are the leading countries in this field. Are. This distribution reflects the worldwide interest and participation in research related to the application of finite elements to groundwater problems. Based on this research, the current popular topics in the world regarding the application of the finite element method in groundwater studies are: "seepage", "deformation" and "stability analysis". The present study not only highlights the relationship between collaborations and scientific advances and trends in scientific collaboration but also serves as a model to show new research directions in the field of finite element applications in groundwater.

The beneficial use of ultrasonic systems has been proven in many applications. Among them, ultrasonic atomization is widely used in various industries, including food and coating industries. Ultrasonic vibrations of liquids can produce fine droplets called atomized fluid. During the fluid atomization process, droplet size and distribution can be precisely controlled so that the droplets become very small and high-level particle distribution is achieved which can be easily evaporated. This method is widely used in various industries, including food industry (for the production of driedpowder products) and coating industry. The key factor that affects droplet size is the frequency and amplitude of the ultrasonic vibrations and the properties of the fluid, including the fluid viscosity and surface tension.

Based on a review of literature, it is clear that the modeling of the ultrasonic method for spray dryers and the production of milk powder has not been done so far. In the present work, first, the research background is reviewed and then, using the relationships provided for the ultrasonic atomization of different fluids in the reviewed articles, the effect of ultrasonic vibrations on the atomization and evaporation of milk as a food and the powder production was studied using spray drying process. Then the effects of various oscillation parameters such as frequency, amplitude and also the temperature of the fluid, which affects its viscosity, density and surface tension, on the rate of atomization of the fluid was investigated. In the present work, we first examine the fluid whose range of properties is true in relations. One of the most widely used liquids in the food industry is milk. By examining the viscosity, surface tension and density of the milk and obtaining the dimensionless numbers We, In and Oh, it is determined that the provided relations can also be used for milk. After calculating the diameter of the evaporated particles of milk due to ultrasonic vibrations as well as the evaporation rate, the independent variables of the research can be changed. First, in the constant physical properties of a fluid, we change the frequency and amplitude of ultrasonic oscillations and studied their effect on the produced particle diameter and evaporation rate. In the next step, with the constant frequency and amplitude of ultrasonic oscillations, the effect of changes in fluid properties (temperature change) on the produced particle diameter and evaporation rate was investigated. In the next stepthe effect of frequency and amplitude of ultrasonic fluctuations as well as changes in fluid properties (temperature change) on the powder diameter produced and the time required for the drying process was investigated. The analysis of all data obtained from the above steps was performed using Mathlab software.

The main and summary results obtained from the present study are as follows:As the amplitude of the vibrations and the temperature of the milk increased, the drying time required for the evaporation of droplets decreased, but the powder diameter and the evaporation rate increased.As the frequency of vibrations increased, the drying time required for the evaporation of droplets increased, but the powder diameter and the evaporation rate decreased.The results showed that quadrupling the amplitude of the vibrations reduces the time required for the droplets to dry by 14.4% and increases the evaporation rate by 62.6%. At a constant temperature of the gas dryer and the milk, changing the frequency from 10 to 40 kHzresults in 21.4% increase in the time required for the droplets to dry. Also, with increasing the temperature of the milk from 15 to 30°C, at a constant frequency and amplitude of vibrations, the time required for drying the droplets decreases by 12.4% and the diameter of the particles produced increases by 11.3%.

In this research, the process of ultrasonic assisted evaporation of whole milk and drying and production of milk powder has been modeled mathematically and thermodynamically. The calculation code was written using Mathlab software and after making sure that the solution conditions are in the desired range of equations, the results were presented. In the present work, the effect of the frequency and amplitude of ultrasonic vibrations as well as the initial temperature of milk on the diameter of the evaporated particles, the evaporation rate, the diameter of the powder produced and the time required for the evaporated droplets to dry by ultrasonic method was investigated.

A decentralization process is a technique to increasing employment in deprived and less developed areas that are emphasized in the first to fourth Iranian development plan. To accomplish this, they must have a proper and useful function for the growth of the surrounding settlements. Decentralization from cities to rural areas provides the foundation for power distribution, which is a clear example of economic development in action. One of the issues that organizations have always faced is finding out how to maximize efficiency and use individuals' full potential to fulfill corporate goals. The goal of this paper is to examine the impact of oil firm employee empowerment on the economic structure from the perspective of villagers using an AHP modeling approach and empowerment criteria. In terms of purpose, the research is applied, and descriptive-survey data gathering is used. The study's statistical population consists of all Torbat Heydariyeh Oil Company personnel. To acquire research data, a standard empowerment questionnaire was employed. The k-s test and Cronbach's alpha were used to confirm the questionnaire, and the regression correlation coefficient method was employed for final validation. According to research, the most It has an effect on human resource empowerment in the criterion of empowerment of workplace index, in the criterion of the criticality of morale and belonging of the organization, in the criterion of the feasibility of morale and belonging of the organization, and finally in the criterion of interest and willingness to work, index of information, knowledge, and job skills.

The enormous application of nano-tweezes in modern technologies and biological purposes leads to new operation situations for these devices, such as an external magnetic field. In this paper, the pull-in behavior of nano-wire-made tweezers immersed in a longitudinal magnetic field is simulated. As the scale dependency can be dominant in ultra-small structures, the constitutive equation is developed based on the consistent couple stress theory. In addition, the influence of van der Waals force and Casimir force are considered in the developed model. A semi-analytical model based on the Homotopy perturbation method is presented to solve the nonlinear governing equation. The influence of different phenomena including size dependency, Casimir force, van der Waals force, and the magnetic field on the pull-in voltage and tweezering range of nano-wire manufactured tweezers is investigated. The obtained results demonstrated that the magnetic field has a considerable effect on the pull-in instability and operating range of nano-tweezers.

In this article, analytical formulation of axisymmetric FGM thick-walled cylinders with power varying of mechanical and thermal properties under transient heating using first order shear deformation theory is presented. Equilibrium equations are derived from virtual work principles and energy method. Also, the transient heat transfer equation is solved by separation of variables, generalized Bessel function, and Eigenfunction method. General thermal boundary condition involving conduction and convection without heat source is considered. At the end the results of the analytical solution are compared with the finite element method, for this aim cylinder is modeled in Abaqus. The effects of time varying on stress and displacement distribution has been studied in this paper. according to results increasing time lead to increase the stress and displacement, by the way after a moment the stress and displacement are time-independent and they become constant. the boundary condition of two ends and thermal boundary condition play a significant role in results.

In the present research, the performance of a Tesla microvalve has been studied under the unsteady three dimensional flow. The time averaged of diodicity is the main criteria for the evaluation of the performance of the valve. By simulation and obtaining the velocity and pressure fields within microvalve, changes in operating parameters of valve including total pressure drop and diodicity parameter in the range of various frequencies studied under sinusoidal excitation. The results showed that the amount of diodicity in steady three dimensional with consideration of third dimension is lower with respect to steady two dimensional flow at entire of studied range of Reynolds numbers. Transient effects on microvalve performance in three dimensional is also studied. It is observed that total pressure drop of unsteady case is greater than steady case at both of forward and backward directions. This important result is in a qualitative agreement with simulation results of other researchers which are obtained by two dimensional simulations. Investigation of effect of applied frequency on Tesla microvalve performance at different Reynolds number is another part of this study. The results showed that at the frequencies lower than 100Hz, the performance of the Tesla microvalve is independent of the frequency, however at higher frequencies greater than 100HZ, its performance is improved by increasing the frequency. Microvalve performance is improved and diodicity is increased by increasing of Reynolds number at all frequencies.