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Search Results: 1 - 10 of 401373 matches for " M. Montazer "
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A New Flexibility Based Damage Index for Damage Detection of Truss Structures
M. Montazer,S. M. Seyedpoor
Shock and Vibration , 2014, DOI: 10.1155/2014/460692
Abstract: A new damage index, called strain change based on flexibility index (SCBFI), is introduced to locate damaged elements of truss systems. The principle of SCBFI is based on considering strain changes in structural elements, between undamaged and damaged states. The strain of an element is evaluated using the columnar coefficients of the flexibility matrix estimated via modal analysis information. Two illustrative test examples are considered to assess the performance of the proposed method. Numerical results indicate that the method can provide a reliable tool to accurately identify the multiple-structural damage for truss structures. 1. Introduction Structural damage detection has a great importance in civil engineering. Neglecting the local damage may cause the reduction of the functional age of a structural system or even an overall failure of the structure. Therefore, damage detection is an important issue in structural engineering. The basis of many damage identification procedures is observing the changes in structural responses. Damage reduces structure’s stiffness and mass, which leads to a change in the static and dynamic responses of the structure. Therefore, the damage detection techniques are generally classified into two main categories. They include the dynamic and static identification methods requiring the dynamic and static test data, respectively. Because of the global nature of the dynamic responses of a structure, techniques for detecting damage based on vibration characteristics of structures have been gaining importance. Presence of a crack or localized damage in a structure reduces its stiffness leading to the decrease of the natural frequencies and the change of vibration modes of the structure [1–3]. Many researchers have used one or more of these characteristics to detect and locate the structural damage. Cawley and Adams [4] used the changes in the natural frequencies together with a finite element model to locate the damage site. Although it is fairly easy to detect the presence of damage in a structure from changes in the natural frequencies, it is difficult to determine the location of damage. This is because damage at two different locations associated with a certain amount of damage may produce the same amount of frequency change. Furthermore, in the case of symmetric structures, the changes in the natural frequencies due to damage at two symmetric locations are exactly the same. There is thus a need for a more comprehensive method of damage assessment in structures. To overcome this drawback, mode shapes have been used for
Zirconium Oxychloride as a Novel Mordant for Natural Dyeing of Wool Yarns
M. Forouharshad,M. Montazer,B. Yadollah Roudbari
Journal of Textiles , 2013, DOI: 10.1155/2013/565382
Abstract: Zirconium oxychloride, a well-known flame retardant, is introduced as a novel mordant for wool dyeing. This has been indicated by mordanting of wool yarns with zirconium oxychloride in different conditions and then dyeing with madder as a famous natural dye. The tenacity, color coordinates, washing, and light fastnesses of the dyed wool confirmed the positive influence of zirconium oxychloride as a useful mordant for wool dyeing with a low impact on the color coordinates. Further, an appropriate washing and light fastness were obtained for the zirconium-oxychloride-mordanted wool yarns. The central composite design (CCD) was used to design the experiments with four variables on the results of tensile strength. Statistical analysis confirmed the optimum conditions obtained through the experimental results. 1. Introduction Wool with high water absorption, good dye ability, high elasticity, reasonable bulkiness, and fire resistance has been used in clothing and floor coverings [1]. The dyeing of wool also poses a challenge for textile chemists due to its complexity of chemical and physical structure [2]. Wool yarns were initially dyed with natural dyes which then the dyeing process improved and transferred from one generation to the other. Although the consumption of natural dyes is high, it has been decreasing by the invention of synthetic dyes. Natural dyes were replaced by synthetic dyes due to their ability to easily match a desired color, increasing variety, high purity, cheap price, and easy processing. However, through production and application of synthetic dyes, producers and consumers have observed several ecological and biological problems [3]. Recently, an interest of using natural dyes in textile coloration has been growing due to the environmental regulation appearing in response to the toxic and allergic reactions associated with synthetic dyes. However, natural dyes are friendly to the environment and exhibit better biodegradability with higher environment compatibility [4]. Madder is a main source of a natural dye producing a variety of anthraquinone dyes in its roots and rhizomes. The main components are di- and tri-hydroxy-anthraquinones, alizarin and purpurin and their derivatives; ruberythric acid (alizarin-primeveroside), pseudopurpurin, and lucidin-primeveroside. Rubiadin, munjisti, quinizarin (1,4 dihydroxyanthraquinone), lucidin, nordamnacanthal, xanthopurpurin, and 1,8-dihydroxyanthraquinone are also identified from plant tissues [5–7]. Farizadeh et al. [8] determined the amount of alizarin, purpurin, and quinizarin in the Iranian
Clinical and Paraclinical Findings of Cerebrovascular Accidents in Children Admitted to Pediatric Medical Center from 1993 till 2003
M Ashrafi,H Montazer Lotfe Elahi,M Dehghani
Journal of Shahid Sadoughi University of Medical Sciences , 2011,
Abstract: Introduction: Stroke is a clinical diagnosis which brings up cerebrovascular diseases. Stroke includes any cerebrovascular accident which leads to local neural defect and lasts more than 24 hours. Stroke has severe and irreversible complications and high rates of recurrence after first episode, therefore we decided to study clinical and paraclinical findings of this disease for better diagnosis and prevention of it. Methods: We prepared a case series study to review medical files of the patients admitted to pediatric medical center with the diagnosis of CVA between 1993 and 2003. 19 patients were assessed in this study. Results: Their mean age was 5.72 (SD=3.801). Among clinical signs hemiparesis was the most common finding (89.5%). Vital signs were normal except for two patients with low-grade fever or hypertension. Such cardiac diseases as cardiomyopathy, valvular disorder, d-TGA, and congestive heart failure were common predisposing factors. According to CT scan reports, 6 patients (31.6%) suffered from deep ischemic stroke, and 5 (21.3%), and 2 patients (10.5%) suffered from superficial ischemic stroke and and hemorrhagic stroke, respectively. 2 patients manifested signs of both superficial and deep ischemic stroke. One of them suffered from Moyamoys syndrome and the other was a known case of MELAS (mitochondrial encepholomyopaty lactic acidosis syndrome). CBC was the most important abnormal test. Conclusion: According to this study, congenital heart diseases are the most common cause of stroke in children. Stroke in children is not frequently associated with vital signs change, and deep ischemic stroke is the most common type of the stroke in children.
Genetic Linkage Analysis of 15 DFNB Loci in a Group of Iranian Families with Autosomal Recessive Hearing Loss
MA Tabatabaiefar,F Alasti,M Montazer Zohour,L Shariati
Iranian Journal of Public Health , 2011,
Abstract: "nBackground: Hearing loss (HL) is the most frequent sensory birth defect in humans. Autosomal recessive non-syn-dromic HL (ARNSHL) is the most common type of hereditary HL. It is extremely heterogeneous and over 70 loci (known as DFNB) have been identified. This study was launched to determine the relative contribution of more frequent loci in a cohort of ARNSHL families."nMethods: Thirty-seven Iranian families including 36 ARNSHL families and 1 family with Pendred syndrome each with ≥ 4 affected individuals, from seven provinces of Iran, were ascertained. DFNB1 contribution was initially studied by DNA sequencing of GJB2 and linkage analysis using the relative STR markers. The excluded families were then sub-jected to homozygosity mapping for fifteen ARNSHL loci."nResults: Sixteen families were found to be linked to seven different known loci, including DFNB1 (6 families), DFNB4 (3 families +1 family with Pendred syndrome), DFNB63 (2 families), DFNB2 (1 family), DFNB7/11 (1 family), DFNB9 (1 family) and DFNB21 (1 family). DNA sequencing of the corresponding genes is in progress to identify the pathogenic mu-tations. "nConclusion: The genetic causes were clarified in 43.2% of the studied families, giving an overview of the causes of ARNSHL in Iran. DFNB4 is ranked second after DFNB1 in the studied cohort. More genetic and epigenetic investiga-tions will have to be done to reveal the causes in the remaining families.
Estimation of Head Rice Yield Using Artificial Neural Networks for Fluidized Bed Drying of Rough Rice
R Amiri Chaijan,M Khosh Taghaza,GH Montazer,S Minaee
Journal of Science and Technology of Agriculture and Natural Resources , 2009,
Abstract: The objective of this research was to predict head rice yield (HRY) in fluidized bed dryer using artificial neural network approaches. Several parameters considered here as input variables for artificial neural network affect operation of fluidized bed dryers. These variables include: air relative humidity, air temperature, inlet air velocity, bed depth, initial moisture content, final moisture content and inlet air temperature. In aggregate, 274 drying experiments were conducted for creating training and testing patterns by a laboratory dryer. Samples were collected from dryer, and then dehulling and polishing operations were done using laboratory apparatus. HRY was measured at several different depths , average of which was considered as HRY for each experiment. Three networks and two training algorithms were used for training presented patterns. Results showed that the cascade forward back propagation algorithm with topology of 7- 13-7-1 and Levenberg-Marquardt training algorithm and activation function of Sigmoid Tangent predicted HRY with determination coefficient of 95.48% and mean absolute error 0.019 in different conditions of fluidized bed paddy drying method. Results showed that the input air temperature and final moisture content has the most significant effect on HRY.
Autosomal Recessive and Sporadic Non Syndromic Hearing Loss and the Incidence of Cx26 Mutations in a Province of Iran
M Hashemzadeh Chaleshtori,M Montazer Zohour,L Hoghooghi Rad,H Pour-Jafari
Iranian Journal of Public Health , 2006,
Abstract: Despite the enormous heterogeneity of genetic hearing loss, mutations in the GJB2 (connexin 26) gene located on “DFNB1” locus (13q12) account for up to 50% of cases of autosomal recessive non-syndromic hearing loss (ARNSHL) in some populations. This study describes the analysis of 100 autosomal recessive and sporadic nonsyndromic hearing loss individuals from 79 families each having at least one deaf child in Chehar Mahal va Bakhtiari province in west of Iran. We have investigated the prevalence of the connexin 26 gene mutations using nested PCR strategy to screen the predominant 35delG mutation and subsequent direct sequencing to detect other Cx26 mutations. Seven different genetic variants were detected from which one novel variant was including 363delC. The 35delG was the most common mutation found in 5 of 79 families (6.3%). Cx26 related deafness mutations (35delG, [V27I; E114G]) and R127H) were found in 12 of 158 chromosomes studied (7.8%). We conclude that the association of Cx26 mutations with deafness in Chehar Mahal va Bakhtiari province is low and looks like most other populations of Iran.
Relationship between Perceived Social Support and Adherence to Medical Advices among Patients with Coronary Heart Disease after By-pass Surgery
Journal of Shahid Sadoughi University of Medical Sciences , 2012,
Abstract: Introduction: The aim of this study was to determine the relationship between perceived social support and adherence to medical advices among patients with heart disease after by-pass surgery in Yazd. Methods: This study was performed with a survey design and cross- sectional method. Data were collected from 75 patients with coronary heart disease after by-pass surgery in Afshar hospital in Yazd. The instruments of data collection were Perceived Social Support(SSS) and Adherence to Medical Advices Questionnaire. Results: There was a significant correlation between perceived social support(P<0.01), perceived support by significant others(P<0.05), and perceived support by family(P<0.05) and adherence to medical advices among patients with heart disease. Hierarchical multiple regression analysis showed that the social-demographic variables(step 1) explained 9.9% and perceived social support(step2) explained 5.8% of the variance in adherence to medical advices. Conclusion: The results showed that perceived social support variable affects adherence to medical advices. Therefore, to reinforce the adherence to medical advices among patients with coronary heart disease it seems necessary to attend to social support in behavioral interventions.
An Intelligent Information Retrieval Approach Based on Two Degrees of Uncertainty Fuzzy Ontology
Maryam Hourali,Gholam Ali Montazer
Advances in Fuzzy Systems , 2011, DOI: 10.1155/2011/683976
Abstract: In spite of the voluminous studies in the field of intelligent retrieval systems, effective retrieving of information has been remained an important unsolved problem. Implementations of different conceptual knowledge in the information retrieval process such as ontology have been considered as a solution to enhance the quality of results. Furthermore, the conceptual formalism supported by typical ontology may not be sufficient to represent uncertainty information due to the lack of clear-cut boundaries between concepts of the domains. To tackle this type of problems, one possible solution is to insert fuzzy logic into ontology construction process. In this article, a novel approach for fuzzy ontology generation with two uncertainty degrees is proposed. Hence, by implementing linguistic variables, uncertainty level in domain's concepts (Software Maintenance Engineering (SME) domain) has been modeled, and ontology relations have been modeled by fuzzy theory consequently. Then, we combined these uncertain models and proposed a new ontology with two degrees of uncertainty both in concept expression and relation expression. The generated fuzzy ontology was implemented for expansion of initial user's queries in SME domain. Experimental results showed that the proposed model has better overall retrieval performance comparing to keyword-based or crisp ontology-based retrieval systems. 1. Introduction The process of searching specific information among a large number of information items is known as information retrieval (IR). Users of IR Systems expect to find the most relevant items to a certain query. The computing parameters such as recall and precision are used for effectiveness appraisal of these systems [1]. Generally, an information retrieval system does not present an ideal behavior. Users often receive large result sets, and they have to spend a considerable time to find these items which are really relevant to their initial queries. Indeed, this kind of searching information will neglect relevant documents that do not contain the index terms which are specified in the user’s queries. Working with specific domain knowledge, the mentioned problem can be tackled by incorporating a knowledge base such as an ontology which builds the relationships between index terms and existing information retrieval systems [2]. One of the motivations of the semantic web is the implementation of ontologies to overcome the limitations of keyword-based search [3]. Ontology is a conceptualization of a domain into a human understandable, machine-readable format consisting of
A Novel Method for Controlling Multi-agent Robot
Shadi Montazer Rahmati,Farshad Farhadnia
Journal of Applied Sciences , 2011,
Abstract: In this study Multi-Agent systems and their control process are introduced. We concentrate on Khepera II robots as a Multi-Agent System and propose a new developed method based on Braitenberg procedure. The most important aspect of this method is utilizing Braitenberg theory for two robots based on impedance control. Our case study is consisted of two Khepera II robots which move on a plane including various obstacles. One of these robots (follower) must track another one (leader) on this plane by sensory connectivity based on Impedance Control (IC) strategy. We control these robots via two heterogeneous networks; the leader robot is connected to a wireless network. The simulation process is performed by Webots software and the results show the effectiveness and high performance of this new algorithm.
Seroprevalence of Cytomegalovirus in Patients with and without Coronary Artery Diseases at Madani Heart Center, Iran
Nasser Safaie,Reza Ghotaslou,Hosain Montazer Ghaem
Acta Medica Iranica , 2010,
Abstract: "nInflammation plays a major role in coronary artery disease (CAD). Currently, it is unclear, whether Cytomegalovirus (CMV) infection is associated with the risk of the atherosclerosis. The aim of this study was to determine the prevalence of anti- CMV antibodies in CAD and non CAD patients undergoing artery bypass surgery. Sera from 157 patients who underwent coronary angiography were tested for CMV by enzyme linked immunosorbent assay (ELISA) at Madani Heart Hospital, Tabriz University of Medical Sciences, Iran. Our study population was 58.6% male and 41.4% female, with an age range of 38 to 86 years. The prevalence of CMV positivity tended to be higher in coronary artery diseases patients than in those without non coronary artery diseases (83.2% versus 63.6%) (P= 0.01). This analysis demonstrated that CMV seropositivity may be a risk factor for CAD in the present study population.
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