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Search Results: 1 - 10 of 52 matches for " Abedin Gagani "
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A Review of the Fatigue Strength of Load Carrying Shear Welded Joints
Filippo Berto, Abedin Gagani, Relly Victoria V. Petrescu, Florian Ion T. Petrescu
American Journal of Engineering and Applied Sciences , 2017, DOI: 10.3844/ajeassp.2017.1.12
Abstract: In the study it is shown an overview of the latest results of two types of joints of the load carrying welded shear. Tests of fatigue have been carried out on the two solutions specific design features proposed and with the aim of improving the resistance of the joints under cycling loading. By hiring the 3D models, was determined Strain Energy Density (SED), in a volume of control which surrounds the lowest point of interest. All of the experimental results have been presented in short. The synthesis shows that all data are within the range of the scattering of the proposed previously in the specialized literature for steel construction welded.
Finite Element Analysis, 3d Model, Lap Joint, Notc h Stress Intensity Factors
Filippo Berto, Abedin Gagani, Raffaella Aversa, Relly Victoria V. Petrescu, Antonio Apicella and Florian Ion T. Petrescu
American Journal of Engineering and Applied Sciences , 2016, DOI: 10.3844/ajeassp.2016.1269.1291
Abstract: Fatigue is a process (succession of mechanisms) which under the action of time-varying strains or deformations modifies the local properties of a material. These can lead to the formation of cracks and eventual rupture of the structure. Fatigue is in particular characterized by an extent of variation in stress which may be well below the yield strength of the material. The main stages of fatigue failure of an assembly are the initiation of cracks (if defects are not already present in the material), the propagation of cracks and the final rupture. The parameters often used to predict the fatigue behavior and thus the number of cycles at break of a structure is: The amplitude of the stress (loading or imposed strain), its average value, the surface state and the medium In which the structure will be used. Even if the study of fatigue is based on theoretical considerations (in particular the mechanics of the rupture), it is essentially an experimental field. The characterization of a material, a part, an assembly, a structure, requires numerous tests and measurements. The work deals with multiaxial fatigue power of specimens which are notched and all made of 40CrMoV13.9. Circumferentially V-notched specimens and semicircular notched were tested under combined tension and torsion loading, both, in phase or out of phase. Geometry of symmetric axis of V notched issues has been characterized of a notch radius constant from (1 mm) and V-notch opening angle of 90°. The semicircular specimens were characterized by a constant notch tip radius. For both situations the net diameter sectional area was 12 mm. The results from multi-axial tests are discussed together with those obtained being all under loading pure torsion and tension by the issues notched having the same geometry. Altogether more than 120 new fatigue data are summarized in the present work. All presented fatigue data are first in terms of nominal amplitudes stress and then reanalyzed in terms of the mean value of the strain energy density evaluated over a finite size semicircular sector surrounding the tip of the notch.
Management and Reduction of Chemical Nitrogen Consumption in Agriculture  [PDF]
Abedin Zafari, Mohammad Hossein Kianmehr
American Journal of Plant Sciences (AJPS) , 2012, DOI: 10.4236/ajps.2012.312A224
Abstract:

Nitrogen is an effective material for improving the crop production. There is a big concern about rising chemical nitrogen usage as fertilizer in soil, because some forms of nitrogen absorbs in soil and causes an increase of environment and water pollution and decrease fertilizer efficiency. Composted cow manure is an important resource of organic nitrogen which improves the soil conditions. However, low density of composted cow manure and inconstant nutrient content are two factors that limit the application of composted cow manure. The densification technology is an effective solution for both problems. In this research first the capability of single screw extruder for production of fertilizer pellets including composted cow manure and nitrogen fertilizer was studied and then the effect of fertilizer pellet on the reduction of chemical nitrogen consumption was evaluated. The response of basil plants was determined in three treatments: T1 control (no fertilizer), T2 (nitrogen fertilizer) and T3 (pellet). The results showed that pelletization can be used as a proper method for slow-release nitrogen fertilizer; enhance nitrogen uptake and reducing the chemical nitrogen consumption. The results also showed that all basil responses (chlorophyll content, total weight, leaves weight, root weight and leaf area) were significantly affected by application of N fertilizer and pellet. While maximum recorded parameters were observed with application pellet.

Web 2.0 and Online Learning and Teaching: A Preliminary Benchmarking Study
Babak Abedin
Asian Social Science , 2011, DOI: 10.5539/ass.v7n11p5
Abstract: The context of online learning has been transformed by the advent of Web 2.0. While universities have just recently started to use Web 2.0 applications, these applications already exist in the students’ personal and educational world. Yet it is still not clear in what ways universities may be able to incorporate Web 2.0 applications in learning and teaching practices. This paper gives an overview of Web 2.0 applications for universities and discusses new opportunities that Web 2.0 has brought for universities. Examples of how some universities have used these applications are then outlined and categorized. The paper also discusses some of the main issues with Web 2.0 applications and provides recommendations for resolving these issues.
Identification of Fertility Enhancing and Inhibiting Factors: A Study on Married Adolescents in Bangladesh
Sumaiya Abedin
Asian Social Science , 2011, DOI: 10.5539/ass.v7n5p191
Abstract: Fertility is associated with complex biological process of women life through the transition of pregnancy and birth. Some socio-demographic variables are hypothesized to affect the level of fertility, many of those factors enhance fertility where as some other inhibit the fertility. Our aim in this study is to reveal the most influential fertility inhibiting and enhancing factors for married adolescents. The intuition behind this is to explore the interaction of both enhancing and inhibiting factors on the level of adolescent fertility. In this sequel, a hypothesized framework based on proximate covariates is used to describe the theoretical relationship among the covariates and factor analysis is applied to identify the dominant fertility enhancing and inhibiting factors. Among all proximate covariates highest level of education is speculated as the most influential fertility inhibiting factor for adolescents.
Operationalizing Off-task Sociability of Asynchronous Computer Supported Collaborative Learning
Babak Abedin,Farhad Daneshgar
Communications of the IBIMA , 2008,
Abstract: Many previous studies have emphasized the role of the sociability of the computer supported collaborative learning (CSCL) environments on learning achievements. Also, recent studies have reported that other than on-task interaction, students have considerable off-task interactions in CSCL environments. Yet, more studies are needed to clarify the off-task aspect of social interactions in CSCL and sociability of the environment. This paper attempts to investigate and operationalize sociability of CSCL environments from off-task point of view in order to further clarify this aspect of CSCL. It first reviews previous sociability questionnaires and instruments and then proposes a list of measure to represent and operationalize off-task sociability of CSCL. The proposed list of measures is then validated through experts’ judges and finally implications are discussed.
Comparison effect of pentobarbital sodium with chloral hydrate anesthesia on post-ischemic damage in an experimental model of focal cerebral ischemia
Abedin Vakili,Gholam Abbas Dehghani
Physiology and Pharmacology , 2008,
Abstract: Introduction: Anesthetic agents, blood pressure, arterial pH and blood gases have found to influence on the pathophysiology of experimental stroke. Despite, there are very few comparative studies about effects of anesthetic agents in animal model of cerebral ischemia. Therefore, in this study, we investigated the effects of chloral hydrate and pentobarbital anesthesia, as comparative study, on infarct size and motor neurological dysfunctions and physiological parameters in a transient model of focal cerebral ischemia. Method: Twenty-four male Sprague-Dawley rats were divided into chloral hydrate (400 mg/kg ip, n=10) and pentobarbital sodium (60 mg/kg ip, n=14) anesthesia groups. Temporary focal cerebral ischemia was induced by 90 min middle cerebral artery occlusion (MCAO), followed by 23 h reperfusion. Physiologic parameters were measured before and after ischemia. Cortical, striatal infarct volumes and motor dysfunction were determined 24 h after MCAO. Results: Cortical and striatal infarct volume in pentobarbital sodium anesthetized rats were 84±8 and 26±2 mm3 that significantly lower from chloral hydrate group (208±10, 62±2 mm3 respectively, P<0.001). Moreover, neurological motor dysfunction significantly was lower in pentobarbital sodium anesthetized in comparison with chloral hydrate group (P<0.01). Physiologic values were similar between anesthetic groups except mean arterial pressure was significantly greater in the pentobarbital group in comparison with chloral hydrate group (P<0.05). Conclusion: Finding of this study indicated that brain injuries and motor neurological deficits in rat anesthetized with chloral hydrate are higher than from pentobarbital sodium groups in temporary model of focal cerebral ischemia. Thus, the effects of anesthetic agents must be considered in experimental cerebral ischemic studies.
Assessing the Effect of Intrathecal Alfentanil in the Quality and Duration of Spinal Anesthesia in Cesarean Section and Side Effects:A Randomize Clinical Trial
M.R Abedin Zadeh
Qom University of Medical Sciences Journal , 2012,
Abstract: Background and Objectives: The use of neuraxial opioids has gained popularity over the last few years; they may cause analgesia by the local anesthetic through direct binding with the specific spinal receptors. The purpose of this study was to compare the effect of intrathecal alfentanil in patients undergoing cesarean section on spinal anesthesia during the operation, and after the operation on spinal anesthesia and side effects. Methods: The study was a randomized prospective and double blind study. 60 young adult females, with ASA physical status I and II with singleton pregnancy undergoing elective cesarean section under spinal anesthesia were randomly allocated to receive spinal elective anesthesia either by using 0.5% hyperbaric bupivacaine 2.5 ml with 0.5 ml normal saline (saline group) or with 0.5ml alfentanil (alfentanil group). Blood pressure, heart rate, respiratory rate, oxygen saturation and side effects were observed before spinal anesthesia and every 5 minutes interval during the surgery, therefore at 30 minute interval until the patient complained of pain. Intraoprative quality of analgesia during spinal anesthesia, time of first feeling of pain (complete analgesia), time of first request of analgesics postoperatively (effective analgesia), side effects (nausea, vomiting, shivering, Purities) and fetal outcomes were evaluated and analyzed. Results: It was shown that 90% of patients in alfentanil group had excellent analgesia Intraopratively, while only 16.7% of patients in the saline group had an analgesia which was qualified as excellent (p<0/001). Complete analgesia also lasted longer in alfentanil group (178±41.8min) compared with saline group (97±28.9min) (p<0/01). The duration of effective analgesia was significantly shorter in the saline group (132±0/32min) compared with the alfentanil group (223.5±0/40.9min)(p<0/01). Hemodynamic variables were similar in both groups (p>0/05). Purities were the most common side effect in the alfentanil group (76.7% of patients). Nausea was less present in alfentanil group than in saline group (50% versus 85%). The incidence of shivering and vomiting did not differ between two groups (p>0/05). APGAR scores were similar in both groups (p>0/05). Conclusion: The addition of alfentanil 250 micrograms to hyperbaric bupivacaine 12.5mg for spinal anesthesia increased the quality of surgical analgesia and duration of postoperative analgesia in patients undergoing cesarean section without increased any side effects. Purities were the most common side effects but they were mild.
Isolation and Molecular Characterization of Xylanase-Producing Bacteria from Drain Water
Narayan Roy,Md. Zainul Abedin
Journal of Biological Sciences , 2002,
Abstract: The xylanase-producing bacterial strains were isolated from drain water. The strains were isolated on xylan-agar media and screening was carried out by β-xylanolysis method. The strains were further confirmed by DNS-method. The isolated strains were identified as Aeromonas on the basis of catalase, oxidase, gram staining and morphological cultural characteristics as well as by different biochemical tests. Multi-drug resistant of these strains were confirmed by antibiotic spread plate method. Disc diffusion method and antibiotic spread plate method showed the same multi-drug resistant pattern. Plasmid DNA was isolated from maximum xylanase-producing strain. Agarose gel electrophoresis of the isolated plasmid DNA in 0.8% agarose showed the presence of only one 30 kb plasmid. The plasmid DNA was transformed into nonxylanase-producing sensitive E. coli LE392. The transformants showed xylanase activity as well as multi-drug resistance. Xylanase activity and multi-drug resistance in Aeromonas strain was proposed to be plasmid mediated.
Effect of Temperature, Pressure and Moisture Content on Durability of Cattle Manure Pellet in Open-end Die Method
Abedin Zafari,Mohammad Hosein Kianmehr
Journal of Agricultural Science , 2012, DOI: 10.5539/jas.v4n5p203
Abstract: Densification of biomass feedstocks, such as pelleting, can increase bulk density, improve storability, reduce transportation costs, and make these materials easier to handle by using existing handling and storage equipment. Evaluation effect of extrusion and raw material parameters on quality parameters of pellet is necessary to determine optimum conditions for designing and constructing a suitable pelleting machine for producing cattle manure pellets. In this study durability of cattle manure pellet that produced by opened die method determined at different temperatures (T), pressures (P) and moisture contents (Mw). Cattle manure samples were compressed with three levels of pressures (3.5,6 and 8 Mpa) and three levels of temperatures (40, 60 and 80 °C) at three levels of moisture contents (50, 55 and 60%). ANOVA results have indicated that linear terms T , P and Mw and interaction of variables were statistically signi?cant at P < 0.01 for pellet durability. Also using cattle manure with 50% moisture content, medium temperature about 40 °C and pressure at 6 MPa resulted maximum pellet durability.
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