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Numerical Simulation of Non-Newtonian Pseudo-Plastic Fluid in a Micro-Channel Using the Lattice Boltzmann Method  [PDF]
Hossein Hamedi, Mohammad Hassan Rahimian
World Journal of Mechanics (WJM) , 2011, DOI: 10.4236/wjm.2011.15029
Abstract: In this paper, the power-law model for a non-Newtonian (pseudo-plastic) flow is investigated numerically. The D2Q9 model of Lattice Boltzmann method is used to simulate the micro-channel flow with expansion geometries. This geometry is made by two squared or trapezoid cavities at the bottom and top of the channel which can simulate an artery with local expansion. The cavities are displaced along the channel and the effects of the displacements are investigated for inline structures and staggered ones (anti-symmetric expansion). The method is validated by a Poiseuille flow of the power-law fluid in a duct. Validation is performed for two cases: The Newtonian fluid and the shear thinning fluid (pseudo-plastic) with n = 0.5. The results are discussed in four parts: 1) Pressure drop; It is shown that the pressure drop along the channel for inline cavities is much more than the pressure drop along the staggered structures. 2) Velocity profiles; the velocity profiles are sketched at the centerline of the cavities. The effects of pseudo-plasticity are discussed. 3) Shear stress distribution; the shear stress is computed and shown in the domain. The Newtonian and non-Newto- nian fluids are discussed and the effect of the power n on shear stress is argued. 4) Generated vortices in the cavities are also presented. The shape of the vortices is depicted for various cases. The results for these cases are talked over and it is found that the vortices will be removed for flows with n smaller than 0.5.
Evaluation of Hydroxyapatite Nanoparticles Biocompatibility at Different Concentrations on the Human Peripheral Blood Mononuclear Cells: An in vitro Study
Hossein Shahoon,Zahra Yadegari,Naser Valaie,Sareh Farhadi,Roya Hamedi
Research Journal of Biological Sciences , 2012, DOI: 10.3923/rjbsci.2010.764.768
Abstract: Hydroxyapatite (Ca10 (PO4)6 (OH)2) is the major inorganic component of hard tissues, the best bio-active materials which is compatible with the bone tissue. In addition, Hydroxyapatite nanoparticles (nHA) have received enormous national attention in medical and dental applications recently, the ultimate fate of the nHA within the body is still unknown. Degradation products of nanomaterials are potentially cytotoxic. Thus, it is essential to assess biocompatibility before their usage in clinical applications. The purpose of this research was to evaluate the biocompatibility of nHA on Human Peripheral Blood Mononuclear Cells (HPBMCs). To evaluation of the biocompatibility of nano-sized, rod-like hydroxyapatite particles, HPBMCs were isolated and cultured on a 96 well plate. Cells were exposed to nHA at the following: 15.5, 31.25, 62.5, 125, 250, 500, 1000, 2000, 4000 and 8000 ppm after 2, 24, 48 and 72 h later for measuring the biocompatibility of material, MTT method was utilized. Measuring the photo, absorption was done by ELISA reader system at 570 nm which assigne the vitality of cell by the value of MTT absorption cells. None of the nHA experimented concentrations were toxic so, it seems that nHA biomaterial has acceptable compatiblity with HPBMCs.
Antibiotic Resistance in Children with Bloody Diarrhea
Hamedi Abdolkarim
Acta Medica Iranica , 2009,
Abstract: Shigellosis is an important public health problem, especially in developing countries. Antibiotic treatment of bacterial dysentery, aimed at resolving diarrhea or reducing its duration is especially indicated whenever malnutrition is present. First-line drugs include ampicillin and trimethoprim sulfamethoxazole(TMP-SMX); however multidrug-resistance has occurred and careful antibiotic selection must be considered in prescribing .When epidemiologic data indicate a rise in resistancy, fluoroquinolones may be used in adults and oral third-generation cephalosporins and nalidixic acid in children. All children (n=2400) with acute diarrhea who were admitted to the Pediatric department of Dr.sheykh Hospital Mashhad, Iran from March 2004 to March 2005 were selected and their stool culture were obtained, then positive cultures (312 cases,13% ) were evaluated by antibiogram. This study showed that in heavily populated areas of IRAN like Mashhad, 97% shigella strain isolated from children with bloody diarrhea were sensitive to nalidixic acid, ciprofloxacin and cefixime and rarely susceptible to ampicillin and cotrimoxazole. There is increasing resistance of Shigella to most of the antibiotics in use, and for this reason, careful selection of antibiotics must use considered in each area. Development and use of new drugs are expensive and have severe limitations in the third world. Simple prophylactic alternatives are therefore, required, such as awareness of hygienic child care practices and early promotion of breast feeding. For treatment of shigellosis in infants Ceftriaxon, and in children Nalidixic Acid is recommended.
Optimizing tensile strength of low-alloy steel joints in upset welding
M. Hamedi
Journal of Achievements in Materials and Manufacturing Engineering , 2006,
Abstract: Purpose: Purpose In resistance upset welding, the heat is generated by resistance of the interface of abutting surfaces to the flow of electrical current in heating and post-weld heating stages. Upset welding typically results in solid-state welds with no melting at the joint. In this paper, the effect of process parameters including heating and post-weld heating power and their corresponding duration along with interference, on the tensile strength of the welded joint are experimentally investigated.Design/methodology/approach: The operational ranges of five process parameters are identified. Sufficient numbers of samples are manufactured and subsequently their mechanical strength is quantified using tensile tests. Then variation of the strength versus the process parameter is evaluated. Metallographic studies are performed that provide metallurgical insight to the bond.Findings: The results suggest that tensile strength of the joint, with variation of each investigated parameter, time, current, and electrical power has an optimal point which shows the optimized set of welding parameters. Also the effect of post-weld heating on the tensile strength is evaluated and shows that this parameter has a remarkable effect exceeding 50% improvement in tensile strength.Research limitations/implications: Should the percentage of power consumption replaced by current; a better comprehension of the process could be achieved.Practical implications: The results recommend that the effect of post-weld hating merits more investigation.Originality/value: The results contribute to a better understanding of the upset welding process. More over this paper shows significance of post-weld heating in maximum tensile strength of the weldment that has not been noted as an important upset welding process in other literature.
A Survey of Multiple Births in Mashad
AK Hamedi,F Akhlaghi
Iranian Journal of Pediatrics , 2002,
Abstract: Ovulation induction drugs in the recent years and modern technologies in treatment of infertility resulted in remarkable increase of multiple births. The goal of the present study was to determine the frequency of multiple births and maternal-fetal as well as neonatal complications of multiple pregnancies in Mashhad during a period of 5 years. Out of 19959 deliveries, 99.3% were singletons, 0.67% twins and 0.015% triples. The incidence of twins’ delivery was 6.7 per 1000 (1 in 150 cases). For triplets this was 0.15 per 1000 (1 in 6666). The majority of mothers aged 20-29 years; the youngest were 15-20 years old. The incidence of multiple births decreased with increasing parity and age over 29 years. Maternal complications included premature delivery (41.6%), preeclampsia (11%), hemorrhage (10.2%), infection (4.3%), and placental detachment (1.4%). Fetal and neonatal complications were observed in 70% and consisted of prematurity, fetal malformations (7.9%), stillbirth (6.1%) and multiple births mortality (13%). A direct relation was noticed between mother’s age and neonate’s weight. Thus, multiple pregnancies must be seen as a high risk for mother and her newborn and should be managed carefully during pregnancy and in labor.
The Relationship Between Educational Psychology and Academic Motivation and Self-efficacy and Minor Training Skills of Teachers
Mitra Attar Hamedi
Research Journal of Applied Sciences, Engineering and Technology , 2012,
Abstract: One of the important issues in the curricula of universities and other educational centers is determining the goals for education to achieve them. In addition to specify the educational goals, regulators of curriculum, shall take measures based on educational objectives and their position in training activities. In this context regarding the importance of science and principles of educational psychology in educational systems, this study seeks to find a significant relationship between academic motivation and self-efficacy with the principles of educational psychology in teacher students. Also the relationship between principles of educational psychology has been determined by minor teaching skills of teachers. In this study the variable of academic motivation is considered as a predictive variable and the variable of self-efficacy is considered as the evidence variable. Another variable in this study is minor skills of teachers. Research hypotheses have been examined by appropriate statistical tests. Results suggested that there is no difference between the self-efficacy of teachers. Educational motivation of teachers familiar with the principles of educational psychology is higher than unfamiliar teachers. Also the minor skill in each teaching session of teachers familiar to the principles of educational psychology teachers is higher than unfamiliar teachers. Also there is no significant relationship between self-efficacy and academic motivation.
Using Fuzzy Decision-Making in E-tourism Industry: A Case Study of Shiraz city E-tourism
Zohreh Hamedi,Shahram Jafari
International Journal of Computer Science Issues , 2011,
Abstract: In recent years, e-commerce has had great impacts on various industries by developing new approaches. Its benefits include faster and easier access to information and the possibility to coordinate for any task before attempting it. In the tourism sector, e-commerce is playing a great role to develop the industry and improve services. On the other hand, combining e-commerce technology with mathematics and the other basic sciences has provided special facilities for flexibility in complying human needs. These include the use of fuzzy knowledge in this technology. Tourism combined with fuzzy knowledge and e-commerce technology will create further expansion of this industry especially in better addressing customers needs and tastes. The aim of this project is to introduce an electronic tourism system (e-tourism) based on fuzzy knowledge for the city of Shiraz, as a case study. This electronic system is in the form of a website, which tourists can use to find an appropriate accommodation by inputting data related to their interests and needs.
"COMPARISON OF MATERNAL AND FETAL/NEONATAL COMPLICATIONS IN GESTATIONAL AND PRE-GESTATIONAL DIABETES MELLITUS "
F. Akhlaghi A. B. Hamedi
Acta Medica Iranica , 2005,
Abstract: Presence of maternal diabetes mellitus (DM) during pregnancy has important consequences for both mother and child. To determine maternal and fetal/neonatal complications of gestational DM and compare them with pre-gestational DM, a prospective study was performed in 100 diabetic women delivered in our hospital from January 2001 to April 2002. Pregnancy outcome in 27 women with gestational DM and 73 women with pre-gestational DM and their offspring were studied and analyzed. The mean age of women was 28 years, women with gestational DM being slightly older than women with pre-gestational DM. Mothers with gestational DM were at increased risk of presenting with pre-eclampsia and preterm labor compared to pre-gestational DM. Frequency of Cesarean section was higher in mothers with pre-gestational DM. Frequencies of abortion and hypoglycemic episodes were similar in gestational DM and pre-gestational DM. Infants born to mothers with pre-gestational DM were at increased risk of suffering from respiratory distress syndrome and congenital malformations but rates of unexplained intrauterine fetal death and large for gestational age were higher in infant of mothers with gestational DM. Gestational and pre-gestational DM are associated with increased risk of maternal and neonatal morbidity. Pregnant women with gestational and pre-gestational DM and their offsprings should be monitored and managed carefully.
A High-level Architecture for Intrusion Detection on Heterogeneous Wireless Sensor Networks: Hierarchical, Scalable and Dynamic Reconfigurable  [PDF]
Hossein Jadidoleslamy
Wireless Sensor Network (WSN) , 2011, DOI: 10.4236/wsn.2011.37026
Abstract: Networks protection against different types of attacks is one of most important posed issue into the network and information security domains. This problem on Wireless Sensor Networks (WSNs), in attention to their special properties, has more importance. Now, there are some of proposed solutions to protect Wireless Sensor Networks (WSNs) against different types of intrusions; but no one of them has a comprehensive view to this problem and they are usually designed in single-purpose; but, the proposed design in this paper has been a comprehensive view to this issue by presenting a complete Intrusion Detection Architecture (IDA). The main contribution of this architecture is its hierarchical structure; i.e. it is designed and applicable, in one, two or three levels, consistent to the application domain and its required security level. Focus of this paper is on the clustering WSNs, designing and deploying Sensor-based Intrusion Detection System (SIDS) on sensor nodes, Cluster-based Intrusion Detection System (CIDS) on cluster-heads and Wireless Sensor Network wide level Intrusion Detection System (WSNIDS) on the central server. Suppositions of the WSN and Intrusion Detection Architecture (IDA) are: static and heterogeneous network, hierarchical, distributed and clustering structure along with clusters' overlapping. Finally, this paper has been designed a questionnaire to verify the proposed idea; then it analyzed and evaluated the acquired results from the questionnaires.
Designing an Agent-Based Intrusion Detection System for Heterogeneous Wireless Sensor Networks: Robust, Fault Tolerant and Dynamic Reconfigurable  [PDF]
Hossein Jadidoleslamy
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2011, DOI: 10.4236/ijcns.2011.48064
Abstract: Protecting networks against different types of attacks is one of most important posed issue into the network and information security domains. This problem on Wireless Sensor Networks (WSNs), in attention to their special properties, has more importance. Now, there are some of proposed solutions to protect Wireless Sensor Networks (WSNs) against different types of intrusions; but no one of them has a comprehensive view to this problem and they are usually designed in single-purpose; but, the proposed design in this paper has been a comprehensive view to this issue by presenting a complete architecture of Intrusion Detection System (IDS). The main contribution of this architecture is its modularity and flexibility; i.e. it is designed and applicable, in four steps on intrusion detection process, consistent to the application domain and its required security level. Focus of this paper is on the heterogeneous WSNs and network-based IDS, by designing and deploying the Wireless Sensor Network wide level Intrusion Detection System (WSNIDS) on the base station (sink). Finally, this paper has been designed a questionnaire to verify its idea, by using the acquired results from analyzing the questionnaires.
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