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Search Results: 1 - 10 of 13249 matches for " Talisa Mohammad Nejad "
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Trilinear Hexahedra with Integral-Averaged Volumes for Nearly Incompressible Nonlinear Deformation  [PDF]
Craig D. Foster, Talisa Mohammad Nejad
Engineering (ENG) , 2015, DOI: 10.4236/eng.2015.711067
Abstract: Many materials such as biological tissues, polymers, and metals in plasticity can undergo large deformations with very little change in volume. Low-order finite elements are also preferred for certain applications, but are well known to behave poorly for such nearly incompressible materials. Of the several methods to relieve this volumetric locking, the \"\" method remains popular as no extra variables or nodes need to be added, making the implementation relatively straightforward and efficient. In the large deformation regime, the incompressibility is often treated by using a reduced order or averaged value of the volumetric part of the deformation gradient, and hence this technique is often termed an \"\" approach. However, there is little in the literature detailing the relationship between the choice of \"\" and the resulting \"\" and stiffness matrices. In this article, we develop a framework for relating the choice of \"\" to the resulting \"\" and stiffness matrices. We examine two volume-averaged choices for \"\" , one in the reference and one in the current configuration. Volume-averaged \"\" formulation has the advantage that no integration points are added. Therefore, there is a modest savings in memory and no integration point quantities needed to be interpolated between different sets of points. Numerical results show that the two formulations developed give similar results to existing methods.
Impact of E-Learning on Learning and Realizing Information Society
Mohammad Behrouzian Nejad,Ebrahim Behrouzian Nejad
Research Journal of Applied Sciences, Engineering and Technology , 2012,
Abstract: With entering to information age, education is one of the important areas which were heavily influenced by information and information technology. Information and Communication Technology (ICT) can be used as important and powerful tool to improve quality and efficiency of education. By means of e-learning the traditional teaching methods can be changed so that it is not necessary to attend in the classroom physically. In fact e-learning is a new paradigm of remote education. The continuous evolution of ICT requires that all citizens have the necessary skills to use these technologies and to access information for efficient individual functioning in the information society. This study will introduce main concepts of e-learning, information technology and information society. This study show that e-learning is a major and primary issue, so it is can be an alternative or replacement for traditional learning methods. Also this study examines the issues surrounding the implementation and impact of e-learning to achieve information society.
Microfacies and Sedimentary Environments of the Fahliyan Formation from the Southwest of Iran (Shiraz, Zagros)  [PDF]
Mahnaz Parvaneh Nejad Shirazi, Fatemeh Dashtaby Jahromi, Mohammad Bahrami
Open Journal of Geology (OJG) , 2013, DOI: 10.4236/ojg.2013.32008
Abstract:

The Fahliyan Formation is a carbonate sequence of Lower Cretaceous (Berriasian-Hauterivian) in age and was deposited in the Zagros sedimentary basin. This formation is a part of Khami Group and is a reservoir rock in Zagros Basin. This formation was investigated by a detailed petrographic analysis in order to clarify the depositional facies and sedimentary environment in the Kuh-e-Gadvan in Fars Province. Petrographic studies led to the recognition of nine microfacies that were deposited in four facies belts: tidal flat, lagoon, and barrier and shallow open-marine. An absence of turbidite deposits, reefal facies, and gradual facies changes indicate that the Fahliyan Formation was deposited on a carbonate ramp.

The Causes and Risk Factors of Tuberculosis Deaths in Khuzestan
Alavi Seyed Mohammad,Salami Nejad
Acta Medica Iranica , 2009,
Abstract: Tuberculosis (TB) is one of the 10 leading cause of deaths in developing countries. Understanding the cause and risk factors of TB death and lowering them can reduce its mortality rate. The aim of this study was to assess the cause and risk factors for death of tuberculosis. A retrospective descriptive study was conducted in Khuzestan province in the south west of Iran, from 2002 to 2006. Medical records of tuberculosis cases over the 5-year period were reviewed and death data were analyzed. Including criteria were documented TB diagnosed based on National Tuberculosis Program (NTP). Extracted data were analyzed in SPSS 11.5 system and by chi squared test. One hundred and twenty five deaths (3.15%) with mean age of 48.96±10.03 years were detected. Risk factors for death were: cigarette smoking, diabetes, chronic peritoneal dialysis, MDR-TB, imprisonment, AIDS and injection drug usage. 93 deaths (74.4%) were directly attributed to tuberculosis. Overwhelming TB disease, hemoptysis, AIDS/HIV and MDR-TB were the cause of death with the rate of 69.9%, 11.8%, 9.7% and 8.6%, respectively. 32 (25.6%) deaths were due to medical problems unrelated to TB, among which were cardiovascular diseases, bacterial super infection and cancers with the rate of 25%, 21.9% and 15.6%, respectively. The deaths of TB not only are directly related to TB, but also are caused due to comorbid conditions. Overwhelming TB disease, hemoptysis, cardiovascular diseases, bacterial super infection and cancers are the main cause of death. MDR-TB, imprisonment, AIDS and injection drug usage are the main risk factors for TB mortality.
Stabilization of Laser Frequency Based on the Combination of Frequency Locking and Power Balance Methods
Saeed Olyaee,Shahram Mohammad Nejad
Journal of Applied Sciences , 2007,
Abstract: In this study, a new laser frequency stabilizer based on the combination of power balance and frequency locking methods is presented. These methods have been widely used in the two-mode laser frequency stabilizers. But in this study, we design and simulate an optical setup and thermal cavity controller to improve the frequency stability of three-mode He-Ne laser. Stabilization of the secondary beat frequency (frequency locking) and amplitudes of three modes (power balance) cause standing position of them to be fixed in the gain profile. The results of simulations by SIMULINK indicate that thermal coefficient of the laser cavity and frequency stability are equal to 1.2 Hz/nm and 3 parts in 1010, respectively.
Characterization of Elliptically Polarized Light and Rotation Angle of PBS in Three-Longitudinal-Mode Laser Interferometer Using the Jones Matrices
Saeed Olyaee,Shahram Mohammad Nejad
Journal of Applied Sciences , 2007,
Abstract: In this study, the periodic nonlinearities resulting from ellipticity of polarized light and rotation angle of Polarizing Beam Splitter (PBS) with respect to the laser axis are presented. The nonlinearity in the three-longitudinal-mode laser interferometer is mathematically modeled using the Jones matrices. Based on the nonlinearity compensation for two-color interferometers, a new optical setup and signal conditioner circuit is also designed. Using the nonlinearity compensation setup, the peak-to-peak nonlinearity of 2.64 nm due to two-elliptically polarized modes in combination with rotation angle of polarizing beam splitter is successfully reached 26 pm.
Transient Thermoelastic Analysis of Pressurized Rotating Disks Subjected to Arbitrary Boundary and Initial Conditions
Mohammad Zamani Nejad,Azam Afshin
Chinese Journal of Engineering , 2014, DOI: 10.1155/2014/894902
Abstract: This paper focuses on exact analytical solution of transient thermoelastic behaviors of rotating pressurized disks subjected to arbitrary boundary and initial conditions. The pressure, inner radius, and outer radius are considered constant. The basic thermoelasticity theory under generalized assumptions is used to solve the thermoelastic problem. Using the method of the separation of variables, the relations of temperature and transient thermal stresses in the radial direction are obtained. In the case study, the disk is considered under heat flux. Some useful discussions and numerical examples are presented. The analytical results were compared with those of the finite element method and good agreement was found. The relations obtained in this paper can be applied to any arbitrary boundary and initial conditions. 1. Introduction The rotating disks subjected to mechanical and transient thermal loads are widely used in many engineering fields such as aerospace, mechanical, naval, nuclear energy, chemical plant, electronics, and biomaterials. Therefore, much research has been conducted in this field. Cheung et al. [1] investigated the problem of transient thermal stresses in a solid elastic homogeneous and isotropic sphere for uniform and nonuniform local surface heating. Sugano [2] analyzed the problem of transient thermal stresses in a homogeneous transversely isotropic finite cylinder due to an arbitrary internal heat generation. A transient response of one-dimensional axisymmetric quasistatic-coupled thermoelastic problems was studied by Yang et al. [3]. Transient thermal stresses in cylindrically orthotropic tubes were obtained by Kardomateas [4]. The transient thermal stresses in a homogeneous cylindrically orthotropic hollow cylinder due to a constant temperature were imposed on one surface and heat convection into a medium at the other surface was studied by Kardomateas [5]. Ashida et al. [6] presented a general solution technique for transient thermoelasticity of transversely isotropic solids in cylindrical coordinates. For quasistatic problems, and without considering the effect of inertial term, Yee and Moon [7] obtained the closed-form solutions of the orthotropic hollow cylinder subjected to an arbitrary axisymmetric temperature distribution. Assuming that the material properties vary nonlinearly in the radial direction and that Poisson’s ratio is constant, Zamani Nejad and Rahimi [8] obtained closed-form solutions for one-dimensional steady-state thermal stresses in a rotating functionally graded pressurized thick-walled hollow circular
Developing a Risk-Based Approach for Optimizing Human Reliability Assessment in an Offshore Operation  [PDF]
Ahmad BahooToroody, Mohammad Mahdi Abaiee, Reza Gholamnia, Mohammad Bahoo Torody, Nastaran Hekmat Nejad
Open Journal of Safety Science and Technology (OJSST) , 2016, DOI: 10.4236/ojsst.2016.61003
Abstract: Human error plays a pivotal rule in all aspects of engineering activities such as operation, maintenance, design, inspection and installation. Industries are faced up to various significant human errors and consequently irrecoverable loss each year, but still there is a lack of heeds to qualify as well as quantify such errors. This paper tries to estimate the probability of failure in lifting of light structures in sea by considering human errors. To do this, a strong qualifying tool such as Functional Resonance Analysis Method (FRAM) is applied to develop high risk accident scenario by considering non-linear socio-technical interaction in system. Afterwards, human error probability is calculated for each activity using the Success Likelihood Index Method (SLIM) based on resonance that is carried out in FRAM network. Then Event Tree (ET) is conducted to assess consequences. The present study is aimed to interpret the importance of attentions to qualitative methods in implementing quantitative risk analyses to consider human error in calculation. The final outcome depicts that considering human error in the process of risk assessment will result in more accuracy and reliability in final Risk Probability Number (RPN). The developed methodology has been applied to a case study of an offshore installation.
Using Data Mining Techniques to Increase Efficiency of Customer Relationship Management Process
Mohammad Behrouzian Nejad,Ebrahim Behrouzian Nejad,Ali Karami
Research Journal of Applied Sciences, Engineering and Technology , 2012,
Abstract: Recently the Customer Relationship Management (CRM) has been achieved an increasing popularity in business management. CRM includes all the steps which an organization employs to create and establish beneficial relationships with the customers. Using technologies such as data warehousing and data mining CRM can be introduced as a new area where companies can gain the competitive advantage. Via CRM system a company can improve its processes to deliver better service at a lower cost. By use of data mining techniques, companies can extract hidden information of the customers from large databases. So, organizations can determine the value of customers and predict their future behavior and requirements. Data mining tools can answer business questions which were time-consuming to track in the past. We believe that it is possible to improve CRM efficiency, to have an effective and rapid response to customer needs, by integrating CRM and data mining techniques. In this study we investigate major concepts of CRM and data mining. Also we introduce our idea to employ data mining techniques in CRM. This study show that using data mining techniques in CRM will improve CRM's efficiency and provide a better prediction ability to companies, organizations and industries to achieve more Profitability.
Biostratigraphy and Mass Extinction Pattern across the Cretaceous/Paleogene Boundary, Northern Alborz, Iran  [PDF]
Masoud Asgharian Rostami, Mohammad Vahidinia, Ebrahim Ghasemi-Nejad, Abbas Sadeghi
Open Journal of Geology (OJG) , 2013, DOI: 10.4236/ojg.2013.31005
Abstract:

High resolution sampling across the Cretaceous/Paleogene boundary (K/Pg) at the Galanderud section in northern Iran provides the most expanded and continuous section for us to consider biostratigraphy and the mass extinction pattern of Cretaceous planktic foraminifera. Based on planktic foraminifera, four biozones and five sub-biozones have been identified across the K/Pg boundary. These biozones include the Abathomphalus mayaroensis Biozone (Plummerita hantkeninoides subbiozone), the Guembelitria cretacea Biozone (including two sub-biozones: the Hedbergella holmdelensis and the Parvularugoglobigerina longiapertura), the Parvularugoglobigerina eugubina Biozone (including two subbiozones: the Parvularugoglobigerina Sabina and the Eoglobigerina simplicissima) and finely the Parasubbotina pseudobulloides Biozone. Planktic foraminiferal extinction occurred over a brief period, with 3% of the species disappearing in the late Maastrichtian, and 72% of the species becaming extinct at the K/Pg boundary. About 25% of the species survived into the early Danian. Extinction of 73% of the species at the K/Pg boundary is very compatible with the effect of a large asteroid impact.

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