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Control Application of Piezoelectric Materials to Aeroelastic Self-Excited Vibrations
Mohammad Amin Rashidifar,Darvish Ahmadi
Shock and Vibration , 2014, DOI: 10.1155/2014/509024
Abstract: A method for application of piezoelectric materials to aeroelasticity of turbomachinery blades is presented. The governing differential equations of an overhung beam are established. The induced voltage in attached piezoelectric sensors due to the strain of the beam is calculated. In aeroelastic self-excited vibrations, the aerodynamic generalized force of a specified mode can be described as a linear function of the generalized coordinate and its derivatives. This simplifies the closed loop system designed for vibration control of the corresponding structure. On the other hand, there is an industrial interest in measurement of displacement, velocity, acceleration, or a contribution of them for machinery condition monitoring. Considering this criterion in quadratic optimal control systems, a special style of performance index is configured. Utilizing the current relations in an aeroelastic case with proper attachment of piezoelectric elements can provide higher margin of instability and lead to lower vibration magnitude. 1. Introduction The dependence of mechanical and electrical properties of piezoelectric materials on their application in various materials as patches or layers makes them an appropriate sensor or actuator for vibration control of structures. In sensing situation, the mechanical and creep deformations of structures can be determined by measuring the electrical potential produced in piezoelectric materials. This property is termed the direct property of the piezoelectric material. Then an effective feedback mechanism sends an electric signal to an actuator to keep the vibration of the mechanical system to a minimum. In actuator applications, the inverse piezoelectric effect is used. Recently, this technique is widely used in the active control of vibrations, deformation control of structures, and aerospace industries. This technique has been investigated by research in solid and aeroelastic areas. In solid, Gaudenzi et al. [1] investigated the vibration control of an overhung beam by means of finite element approach based on Euler-Bernoulli beams. They studied state feedback and velocity feedback control of vibration. Moreover, Q. Wang and C. M. Wang [2] implemented vibration control of a beam with piezoelectric patches by taking finite element method into account. They determined an optimized position for an appropriate actuator and the subsequent vibration amplitude of a hinged-hinged beam by applying a feedback control procedure and converting the finite element model into its state space form. Narayanan and Balamurugan [3] studied
Investigating the effects of intellectual capital on organizational performance measurement through organizational learning capabilities
Hasan Darvish,Ali Akbar Ahmadi,Ali Reza Kafashzadeh,Samira Farid
Management Science Letters , 2013,
Abstract: During the past few years, there have been growing interests on intellectual capital due to industrial changes on the market. Thus, identifying different ways to create, manage, and evaluate the impact of intellectual capital has remained an open area of research. One of the most important organizational capabilities, which could help organizations create and share knowledge is to effectively use knowledge to create competitive advantage. The primary objective of this study is to investigate the effects of intellectual capital on other components and their impacts on organizational learning capability. The statistical population includes 500 employees of an Iranian organization. The study uses a sample size including 273 people using Morgan statistical table and Cronbach's alpha is calculated as 0.838. The results of this survey indicate that human capital, relational capital and learning capabilities have positive impact on organizational performance. In addition, relational capital positively impacts learning capability and human capital influences positively on relational capital.
FeCl3 Catalyzed One Pot Synthesis of 1-Substituted 1H-1,2,3,4-Tetrazoles under Solvent-Free Conditions  [PDF]
Fatemeh Darvish, Shima Khazraee
International Journal of Organic Chemistry (IJOC) , 2015, DOI: 10.4236/ijoc.2015.52009
Abstract: An efficient procedure for the preparation of 1-substituted-1H-1,2,3,4-tetrazoles via a three-component condensation of triethyl orthoformate, amine, and trimethylsilyl azide using inexpensive and environment-friendly FeCl3 as catalyst under solvent-free conditions has been reported. The reaction generates the corresponding 1-substituted tetrazole in excellent yields.
Investigation Progressive Collapse Behaviour of Double Layer Barrel Vault Space Structures  [PDF]
Mahdi Darvish Hashemi, Hadi Zarrintala
World Journal of Engineering and Technology (WJET) , 2015, DOI: 10.4236/wjet.2015.33C050

Space double-layer grids are structures that are vulnerable facing progressive collapse phenomenon. So some methods should be studied for space double-layer grids that their collapse behaviors change from a brittle one into a soft and ductile. Within this study, than of these structures progressive collapse behavior has been studied. This study answers this question that to which members early to take collapse of double-layer space barrel vaults grids. This research can be identified with the critical members of the progressive failure and overall structural damage avoided.

The Relasionship among Quality and Structure of Social Capital and Organizational Entrepreneurship: a Case Study at Mazinoor Lighting Company
Annals of Dun?rea de Jos University. Fascicle I : Economics and Applied Informatics , 2011,
Abstract: Newday's in addition to different human, financial and economical capital, there is another capital called" Social capital" which is used .this concept points to the connections and relationships between the members of a network as a valuable capital which aims at a achieving the members purpose through the creation of norms and mutual reliance social, is viewed as a suitable context for reaching success and profiting from human and physical capital. Managers and those who contestability social investment in organizations, are able to set appropriate condition for succeeding in their profession and organization otherwise (without social capital) other resource will lose their effects and there will be problems and difficulties in the direction of cultural and economical development and evolution. In considering the direction of cultural and economical development and evolutions.in considering the relationships between social capital and organizing recreation , it can be said that social capital facilitates risk-taking and recreation behavior ,which is an essential element of recreation and directly enters the people's practical operation and really capital totally enhances their general activity as in group recreations.In the proposal, the researcher examinical the relationship between social capital and entrepreneurship in lighting industry In mazinoor co. in Mazandaran province and to do this, pearson correlation , two –sentence test and freedman test have been used. Finally the results indicated that a positive an meaningful relationship exists between social capital and it's dimension and entrepreneurship in organization also the correlation crefficient of the structuring dimension of social resource has a mire importance in mazinoor co. The recreation index of the product is a top priority in relation to in entrepreneurship.
Stimulation of medical decision expert system by using of time color Petri net method
Neda Darvish
International Journal of Computer Science Issues , 2012,
Abstract: The role of management science methods in solving the health problems is a clear potential for improvement. Such an approach in an advanced health care system is achieved for improving the condition of treatment, increasing the efficiency and useful planning of time and human resources. In this study, by using one of the artificial intelligence methods, time color Petri net method, the stimulation of the hospital environment and designing of expert system for optimizing of system, will be done.
A new algorithm for mixed equilibrium problem and Bregman strongly nonexpansive mappings in Banach spaces
Vahid Darvish
Mathematics , 2015,
Abstract: In this paper, we study a new iterative method for a common fixed point of a finite family of Bregman strongly nonexpansive mappings in the frame work of reflexive real Banach spaces. Moreover, we prove the strong convergence theorem for finding common fixed points with the solutions of a mixed equilibrium problem.
Influence of Ferric and Ferrous Iron on Chemical and Bacterial Leaching of Copper Flotation Concentrates  [PDF]
Ali Ahmadi
International Journal of Nonferrous Metallurgy (IJNM) , 2012, DOI: 10.4236/ijnm.2012.13006
Abstract: The effects of ferrous and ferric iron as well as redox potential on copper and iron extraction from the copper flotation concentrate of Sarcheshmeh, Kerman, Iran, were evaluated using shake flask leaching examinations. Experiments were carried out in the presence and absence of a mixed culture of moderately thermophile microorganisms at 50?C. Chemical leaching experiments were performed in the absence and presence of 0.15 M iron (ferric added medium, ferrous added medium and a mixture medium regulated at 420 mV, Pt. vs. Ag/AgCl). In addition, bioleaching experiments were carried out in the presence and absence of 0.1 M iron (ferric and ferrous added mediua) at pulp density 10% (w/v), inoculated bacteria 20% (v/v), initial pH 1.6, nutrient medium Norris and yeast extract addition 0.02% (w/w). Abiotic leaching tests showed that the addition of iron at low solution redox potentials significantly increased the rate and extent of copper dissolution but when ferric iron was added, despite a higher initial rate of copper dissolution, leaching process stopped. Addition of both ferrous and ferric iron to the bioleaching medium levelled off the copper extraction and had an inhibitory effect which decreased the final redox potential. The monitoring of ferrous iron, ferric iron and copper extraction in leach solutions gave helpful results to understand the behaviour of iron cations during chemical and bacterial leaching processes.
Hassan Darvish,Hadi Ahmadnia
Acta Didactica Napocensia , 2011,
Abstract: The main purpose of this research was whether compensation system in education organization of Zandjan province can distinguish between employees based on their personal characteristics. To meet the purpose, Of 12950 monthly paid teachers in different age, academic paper, organizational positions and length of service, Finally 2554 of employees were selected based on cluster random sampling in 5 cluster that each cluster represents one area. To analyze the research questions, descriptive and inferential statistics like path analysis and discriminant analysis using by Spss 11.0 were served. The relationship between outcome variable, monthly salary, and Job category is 0.73 and between monthly salary and length 0f service is 0.815.Both of them were significant (P<.01), showing that there is a positive and direct relationship between variables. Finally the causal model encompassing personal variables influencing the salary is drawn.
An empirical study to investigate the effects of thinking styles on emotional intelligence: A case study of Jihad Agriculture Organization of east Azerbaijan province
Hassan Darvish,Habibeh Ayagh
Management Science Letters , 2013, DOI: 10.5267/j.msl.2013.04.014
Abstract: An empirical study to investigate the effects of thinking styles on emotional intelligence among employees of agriculture industry in east Azerbaijan province. The proposed study uses a standard thinking style questionnaire originally developed by Sternberg and Wagner (1992) [Sternberg, R. J., & Wagner, R. K. (1992). Thinking styles inventory. Unpublished test, Yale University]. There are 716 employees working for this agriculture-based unit and the study uses random sampling technique and chooses 255 employees for this study. Cronbach alpha has been used to verify the overall questionnaire and different tests such as Kolmogorov-Smirnov and Pearson correlation test are used to examine different hypotheses of this survey. The results indicate there is positive and meaningful relationship between thinking style and emotional intelligence. We can also confirm that four thinking style’s components including functions, levels, scope and learning have meaningful impact on emotional intelligence when the level of significance is five or even one percent. However, forms did not have any meaningful impact on emotional intelligence.
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