Showing 18 results for Abbaszadeh
Volume 2, Issue 1 (4-2002)
Abstract
In this paper, the effects of reflected waves of the facets on the internal optical intensity of semiconductor DFB lasers are investigated. The uniformity of optical intensity along the cavity length is evaluated with flatness parameter. The dependence of this parameter on coupling coefficient, reflectivity and grating phase at the facets is also studied. This investigation shows that in some structures reflected waves of the facets cause optical intensity along the cavity length to have more uniformed distribution than a DFB laser with anti-reflective facets. It is also shown that flatness parameter is very sensitive to grating phase .Thus it is necessary for designing a DFB laser to consider the effects of reflected wave and grating phase at both ends of cavity in order to increase the stability of the laser against SHB (Spatial Hole Burning) effect. The effects of reflectivity and grating phase on longitudinal distribution of photon and carrier density above threshold are investigated, too.
Volume 3, Issue 3 (9-2015)
Abstract
Aim: Sexual function is influenced by different individual and environmental factors. Female sexual dysfunction (FSD) can lead to serious conditions for women and their family. The present study aimed to identify the prevalence and risk factors for FSD, in Kashan, Iran.
Methods: In this cross-sectional study, a convenience sample of 200 women refering to educational gynecology clinics and meeting the inclusion criteria was selected in Kashan, Iran, 2014. Three anonymous self-administered questionnaires were completed by the participants: Demographic, the Female Sexual Function Index (FSFI), and the Depression, Anxiety and Stress Scale-21 (DASS-21). Chi-square, T-test, Mann Whitney's and Pearson's correlation coefficients were performed for the determination of factors associated with FSD. A score less than 28 out of a possible score of 36 suggests the presence of FSD based on FSFI.
Findings: Of total participants, 119 (59.5%) had FSD. Thirty-nine percent reported desire disorders, 37% arousal disorders, 28.5% lubricant disorders, 24%5 orgasmic disorders, 19.5% pain disorders, and 22.5% satisfaction disorders. Sexual dysfunction was more common in depressed, anxious and stressed and low educated women with older age and longer duration of marriage.
Conclusion: Sexual dysfunction is common among women and some demographic and emotional problems likely contribute to the experience of sexual dysfunction. This finding may have implications on the clinical evaluation of sexual function and identifying the effect of demographic and psychological factors on FSD in women.
Volume 4, Issue 4 (Winter 2021)
Abstract
Abstract
Research subject: Due to the drought and lack of water resources, many efforts have been made to store water properly recently. Using of multilayer polyethylene tanks is an efficient measure in order to solve this problem and it has received considerable attention. Proper manufacturing conditions will greatly improve the strength of these tanks and their applications.
Research approach: In this study, the effect of cooling process on the final properties of polyethylene tanks prepared by rotational molding method is investigated. Three different cooling methods comprised of cooling with water, cooling by air, and quiescent cooling is selected and their mechanical and thermal properties were investigated.
Main results: The results of the tensile test show that as the tank is cooled faster, the elongation at break will be higher. It is also demonstrated that the air cooling method results in the lower elongation at break. The results of the thermal properties show that higher cooling rate creates thicker crystals in the fragment which requires higher energy to overcome these thick crystals. According to the results of the thermal properties and using the softening temperature test it is found that by increasing the cooling rate, the softening temperature will be increased as well which will improve the application of the tank in high temperature conditions. Melt flow rate and density tests are also performed to confirm the results of mechanical and thermal properties, respectively. Charpy impact test is performed at ambient temperature to confirm mechanical behavior induced by crystal structure. All in all, cooling by water performs better than other methods in terms of mechanical and thermal properties.
Volume 6, Issue 1 (3-1999)
Abstract
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Volume 7, Issue 2 (7-2018)
Abstract
Cercospora leaf spot caused by Cercospora beticola has a great negative impact on yield and quality of sugar beet. In the present study, pathogenic and genotypic variation of 24 C. beticola isolates collected from different regions of Iran were studied using RFLP of the Internal Transcribed Spacer (ITS-RFLP), and Random Amplified Polymorphic DNA (RAPD-PCR). Pathogenic variability and genotype × isolate interaction were evaluated in greenhouse experiments on five sugar beet cultivars (FD0018, HM1836, Puma, Eudora and Monatuna). All of the 24 isolates tested were found to be pathogenic on the cultivars with significant variation in disease severity. Results of RAPD analysis showed wide DNA polymorphism among the Iranian C. beticola isolates. Restriction pattern of the internal transcribed spacer of rDNA (ITS1-5.8-ITS4) was studied using three restriction endonucleases: EcoR1, Taq1, and Busr1. The length of undigested DNA fragment of all isolates was estimated to be 500bp without rDNA polymorphism after digestion with EcoR1 (280, 270 bp), Taq1 (330 bp) and Busr1 (240, 220, 90 bp). RAPD and ITS-RFLP markers showed the highest level of genetic diversity which confirms the variation in C. beticola detection.
Volume 10, Issue 1 (Winter 2019)
Abstract
Aims: There are several cell disruption methods for intracellular protein extraction. The aim of this study was to select the best approach for recombinant teriparatide fusion protein extraction from E. coli and achieve the best purification conditions.
Materials & Methods: In this experimental research, bacterial cells were disrupted by different methods such as sonication in different cycles, grinding with liquid nitrogen in two different cell culture volumes, and homogenization at two different pressures. The supernatant and pellet samples were run on sodium dodecyl sulphate gel. All the cell lysates were cultured on LB agar medium and stained with Gram staining method. The Ni2+ affinity chromatography of recombinant teriparatide fusion protein was done under denaturing and non-denaturing conditions, using pH and imidazole concentration gradient, respectively. All samples were taken on sodium dodecyl sulphate-polyacrylamide gel and the amount of purified protein was calculated by Micro-Bradford assay.
Findings: In the 20 and 25 cycles, a large part of the fusion protein led to protein solubilization. In the method of grinding with liquid nitrogen, proteins were more likely to enter the sediment part. The cell disruption was complete in a chemical method. The cell disruption under 50bar homogenization was more than that of 15bar. In chemical degradation and sonication, a large amount of fusion protein led to protein solubilization. In non-denaturing conditions, no recombinant fusion protein was removed from the column with the isolation buffer, but in the denaturing conditions, a large amount of proteins was purified.
Conclusion: The combined method of chemical degradation and sonication leads to approximately 97.7% of protein solubilization, and the purification in denaturing condition has also the suitable result in contrast to non-denaturing condition.
Mohammad Hoseinpour, Masoud Abbaszadeh, Iraj Mirzaee,
Volume 14, Issue 3 (6-2014)
Abstract
Metal foams are a new class of materials which are used excessively in recent decade for their good physical and mechanical properties such as low density yet high strength, as well as their good thermal properties which turned them to a good thermal insulator. The main characteristic of the foams is the existence of pores in them which are distributed randomly. Because of the importance of these materials in engineering and other applications, there has been given importance to modeling of them. In this article, a new method has presented for modeling of closed-cell foams and a program has written in macro environment of CATIA software in Visual Basic language which made the modeling of metallic foams with controllable pore size and density possible. In continue, the effect of the pore size and the number of the holes on the relative density of the foams has studied. Comparing the properties of the modeled foams using the presented algorithm and real foams has shown a good agreement. The modeled foams have the ability to get into the finite-element software.
Volume 14, Issue 3 (5-2012)
Abstract
Jujube (Zizyphus jujube Mill), a valuable medicinal plant, is consumed either as fresh fruit or dried product in Iran. Drying jujube guarantees a longer shelf time while preserving its quality to be used in medical and pharmaceutical industries. In this research paper, the influence of several drying conditions on the effective moisture diffusivity, activation energy, energy consumption and required specific energy in the drying of jujube is presented. Temperature levels of 50, 60 and 70 ºC and hot air velocities of 0.5, 1 and 1.5 (m s-1) were used as the treatments. Effective moisture diffusivity of jujube fruit during the drying process was in the range of 1.1532-5.1895×10-10 (m2 s-1) for the first period and 0.4036–2.3064×10-10 (m2 s-1) for the second period. Also, the values of energy of activation in both periods were determined to be between 34.97 and 74.20 (kJ mol-1). The energy consumption and the required specific energy for drying were in the range of 79.1- 92.46 (kW h) and 203.59 – 900.08 (kW h kg-1), respectively. Results show that energy consumption diminished when temperature increased at each air velocity, while it increased with increasing hot air velocity.
Ali Abbaszadeh Bidokhti, Amir Reza Shahani,
Volume 14, Issue 5 (8-2014)
Abstract
Multiple flaws are frequently occurred in actual components, such as pressure vessels and power plants. These flaws will in some circumstances lead to more severe effects than single flaw alone. Assessment of the interaction behaviour is based on an evaluation of the alignment and combination of these multiple flaws. In the current standards, multiple cracks are treated as an equivalent single crack if the distance between two cracks satisfies a prescribed criterion. First, this study introduces the current alignment and combination rules for through cracks. Following, to investigate the effects of the interaction of cracks, brittle fracture of a plate containig two adjacent cracks is simulated. The effect of cracks distances and crack lengths on stress intensity factors is evaluated. Also, crack growth analysis is simulated based on linear elastic fracture mechanics approach. The extended finite element method has been utilized to model the problem. This method enables the domain to be modeled by finite elements without explicitly meshing the crack surfaces, and hence crack propagation simulations can be carried out without remeshing. Based on the results, a new alignment and combination rule is proposed.
Mehrdad Nasrollahzade, Hassan Moslemi Naeini, Seyed Jalal Hashemi, Behnam Abbaszadeh, Javad Shahbazi Karami,
Volume 15, Issue 12 (2-2016)
Abstract
In recent years, aluminum, magnesium and titanium alloys are highly regarded in the aerospace and automotive industries due to their high strength to weight ratio and resistance to corrosion. The main problem of the use of these alloys is their low formability at room temperature. To solve this problem, the metal forming process is done at high temperatures. Since oil’s heat resistant temperature is not more than 300°c, other fluids such as air and nitrogen gas should be used in high temperatures. In this study, blow forming equipment at high temperatures has developed, and changing of AL6063 tubes cross-section from circular to square has investigated experimentally and compared with the results of the experiments at room temperature. After producing square products, thickness distribution, corner’s radius, forming pressure, and effect of pressure time in corner’s radius at different temperatures were compared and the location of bursting was also examined. The results indicated that by increasing temperature, formed radius and pressure time reduces significantly, so that the amount of radius decreases from 19.5 mm in the temperature of 25°c and 154 bar forming pressure, to 5.8 mm in the temperature of 500°c at 11 bar forming pressure. The results showed that by increasing time pressure, which causes to decrease velocity of process, the formed corners has been sharper. By investigating burst of specimens, bursting occurs in the area of converting circular cross section to square one, which has a high deformation and tensile strain.
Volume 16, Issue 91 (September 2019)
Abstract
Currently, consumers are aware of the side-effects of chemical additives and are more interested in natural antibacterial compounds as food preservatives, like herbal essential oils and extracts. In this study, the antimicrobial effect of some main components of the essential oils, including thymol, carvacrol, menthol and eugenol has been evaluated against Bacillus cereus (PTCC 1154), Pseudomonas nigrifacience (ATCC 19375), Erwinia carotorova (PTCC 1675) and Xanthomonas campestris (PTCC 1473) by broth microdilution method and agar disc diffusion method. According to the results, the lowest MIC was reported for Thymol which was 50 ppm (Pseudomonas nigrifacience, Erwinia carotorova and Bacillus cereus) and the maximum MIC for Pseudomonas nigrifacience was 100 ppm due to menthol and 125, 125 and 108 ppm for Bacillus cereus, Erwinia carotorova and Xanthomonas campestris respectively due to Eugenol. Menthol presented the broadest growth inhibitory zone (8.9 mm) for Pseudomonas nigrifacience and the narrowest inhibitory zone was reported for Eugenol against Erwinia carotorova (5.9 mm). Menthol and eugenol were the strongest and weakest antimicrobial agents respectively (p-value<0.05). However, all tested components inhibited the microorganisms at different levels and are potent to be used as food preservatives.
Mehdi Karimi Firouzjaei, Hassan Moslemi Naeini, Hamidreza Farahmand, Behnam Abbaszadeh, Mohammadmehdi Kasaei,
Volume 17, Issue 10 (1-2018)
Abstract
In this paper, cold roll forming process of a high strength steel pipe using four types of flower pattern including circular, edge, double radius and reverse bending is simulated with finite element method in MSC Marc Mentat software. Due to importance of quality of final pipe and in order to achieve the desired geometry in high strength steel pipes, selecting the appropriate flower pattern to design the pipe roll forming production line is considered. Using finite element simulation results, deformation of sheet in this process is studied and effect of flower pattern type on geometry of final product, which includes curvature distribution, spring back and thickness distribution of pipe, is investigated. Results show that implementing reverse bending flower pattern, leads to reduction in deviation from mean curvature at edge of the sheet up to about 65 percent. Thickness distribution analysis shows that circular and edge flower patterns cause upsetting and thinning of edge of the sheet up to 0.2 millimeters, respectively. But, use of double radius and reverse bending patterns cause average thickness of edge to be well adjusted to reach 2.8 millimeters. Also, circular flower pattern has the lowest value of spring back in terms of variation of mean relative curvature of 0.69 percent and edge deviation of 0.15 millimeters. To validate the finite element simulation, experimental tests were designed and conducted using one forming stand. By comparing resultant data of experimental tests with simulation results, validity of finite element simulation confirmed.
H. Yousefian, H. Moslemi Naeini, R. Azizi Tafti, B. Abbaszadeh,
Volume 18, Issue 9 (12-2018)
Abstract
In this paper, considering the increasing need for high strength and thin pipes in the oil and gas industries, the effects of material strength and the initial thickness of the pipe and the friction between the pipe and the roller, on the distribution of the thickness and ovality of the cross-section of pipe in the process of sizing have been numerically and experimentally investigated. The simulation is performed using the commercial software MSC Marc Mentat. Results of the simulation show that by increasing strength material and reduction of thickness, the ovality of the cross-section of pipe decrease. It has been shown that with a 2.77-fold increase in the yield strength of a pipe with thickness of 2.8 mm, the ovality decreased by 27%. By decreasing the thickness of the St37 pipe from 2.8 to 1.8 mm, the ovality decreased to 2%. These changes increase with increasing yield strength, so that in the alform700 pipe with a thickness reduction of 2.8 to 1.8 mm, the ovality decreased to 45%. Furthermore, the friction condition has very little effect on the ovality of pipe. The validity of the finite element simulation is confirmed by comparison with experimental results.
Volume 18, Issue 121 (March 2022)
Abstract
The aim of this study was to produce biological silage from chicken waste based on fermentation of autogenous bacteria and to evaluate the quality characteristics of the product. In order to produce this product, sampling was performed from selected slaughterhouses in Mazandaran province and biosilage was produced in the form of a one-ton fermenter using autogenous bacteria isolated from the region (fermentation). The final product (dried biosilage powder) was evaluated qualitatively using standard methods and compared with other sources including meat powder, blood powder and kilka fish powder (produced by batch method). The results showed that the amount of protein, fat and protein digestibility in the produced biosilage was 59.09%, 21.30% and 87.41%, respectively. The product produced was in a better condition than meat powder and kilka fish powder in terms of the mentioned indicators. The produced biosilage did not show a significant difference between blood powder in terms of calcium and phosphorus and was at a lower level than kilka fish powder and meat powder. The levels of TVN, PV and TBA in biosilage were measured as 46.56, 4.46 and 2.21, respectively. These indices are in a much more favorable condition in the produced product compared to Kilka meat powder and fish powder. It was further found that the microbial parameters (mold, yeast, coliform, fecal coliform, E.coli) in the samples of meat powder, blood powder and kilka fish powder were relatively higher compared to biosilage of chicken waste. According to the results of the present study, chicken waste has the ability to be converted into biosilage with desirable characteristics that can be used in agriculture and aquaculture industries.
M. Abbaszadeh Gorani, M. Hadad, A. Parvizi,
Volume 20, Issue 5 (May 2020)
Abstract
Rolling ring is one of the most important metal forming processes for fabricating rounded geometries with optimal mechanical properties in the environmental direction. The ability to fabrication of two-layer rings can be used in many industries. One of the properties of these rings is the lightweight with high strength or wear resistance along with high strength. In this research, we have tried to study the ring rolling process of the bonded two-layer ring and its effective parameters during the process using finite element analysis by ABAQUS software and experimental test. The rings are attached for process simulation and empirical testing. In the end, a ring of two-layer of pure Lead 99.99% and Tin 63% was formed. Based on the results obtained from this analysis and according to the dimensions and parameters considered for performing the process, the tension created in the bonded two-layer ring is between the values of 1.146×105-1.800×107Pa and it has a strain of 0-1.187. Its contours of strain and stress are represented to better understand the process. Considering the results obtained from the simulation of the process, an experimental study of the ring rolling process of the bonded two-layer ring was conducted. The method of this study was first designed by the modeling software to design the casting model and then by designing the test, the number of tests required for the experimental test was obtained and then the number of materials needed for the test was calculated. After testing, the mechanical and metallurgical properties of rolled double rolled rings were investigated.
Volume 21, Issue 1 (Spring 2018)
Abstract
Aims: Exercise activity and the use of herbal supplements are effective in regulating vascular contraction by influencing on angiogenesis factors. The purpose of this study was to investigate the effect of caffeine and genistein supplement on cardiac levels of nitric oxide (NO) and vascular endothelial growth factor (VEGF) in wistar rats, following an acute swimming exercise.
Materials and Methods: In this experimental study, 49 male Wistar 8-10-week rats were randomly divided into 7 groups of control, saline, acute exercise, caffeine, genistein, acute swimming exercise plus caffeine, and acute swimming exercises plus genistein (7 rats in each group). Acute exercise included 90 minutes swimming. Dietary supplement groups, taked the caffeine at a rate of 5mg/kg of body weight by gavage and Genistein in the amount of 100mg/kg of body weight by intra peritoneal injection. Two hours after the end of the training session, the levels of NO and VEGF were measured by ELISA. Data were analyzed by SPSS 20 software using one-way ANOVA.
Findings: 90 minutes swimming exercise caused a significant increase in cardiac levels of NO and VEGF in acute exercise, acute exercise plus caffeine, acute exercise plus genistein in comparison to the control and saline groups (p=0.01), while supplementation of caffeine or genistein alone did not significantly increase the levels of cardiac level of these factors compared to control and saline groups.
Conclusion: The supplementation of caffeine and genistein increases the levels of NO and VEGF of the heart tissue of rats following an acute swimming session.
Hassan Badparva, Dr. Hassan Moslemi Naeini, Dr. Mohammmad Mehdi Kasaei, Yaghob Dadgar Asl, Behnam Abbaszadeh,
Volume 22, Issue 1 (January 2021)
Abstract
In this paper, using finite element simulations and experimental results, the changes in deformation length and longitudinal strain in flexible roll forming are investigated and the relationship between them is determined. Flexible roll forming is a novel manufacturing process for producing profiles with variable cross-section. One of the important parameters of this process is the distance from the starting point of the deformation before the forming station to the central cross-section of the rolls at that station, which is called the deformation length. This parameter plays a key role in determining the distance between the forming stations and the deformation behavior of the sheet. The effect of roll diameter and mechanical properties of the sheet on the deformation length is also determined. The results showed that the maximum deformation length occurs when forming the stretching zone of the channel profile with variable cross-section, which is due to the additional tension applied to the edge due to the concave geometry of the flange in this zone. The results also showed that with increasing roll diameter and yield stress, the deformation length in all four of the stretching and compression zones and the slim and wide areas of the channel profile with variable cross-section increases, while with increasing sheet thickness, the deformation length in these zones decreases.
Volume 22, Issue 3 (4-2020)
Abstract
Satureja sahendica Bornm is an endemic, native, and aromatic plant in Iran, with thymol being its main and major volatile component, which is used in food and pharmaceutical industries. Increasing the oil yield and phenolic compounds in essential oil leads to increased medicinal effects. In this study, the effects of mycorrhizal fungi (Glomus mosseae, G. intraradices, and combination of G. mosseae and G. intraradices) and different levels of water stress [D1= Control (no water stress), D2= No irrigation during stem elongation till blooming, D3= No irrigation at the blooming up to start of flowering, and D4= No irrigation at 50% flowering up to full flowering] were studied on S. sahendica oil, in two years. When the seedlings were transferred to the field, 10 g of mycorrhiza fertilizer (containing mycorrhizal fungus spores) were added to the rhizosphere of each seedling. The plants were harvested at full flowering and the essential oils were obtained by hydro-distillation and analyzed by GC and GC/MS. The highest amount of oil yield (66.13 kg ha-1) was obtained using G. intraradices in non-stress conditions in the second year. The highest percentage of thymol was obtained in G. mosseae×control in the first year (74.59%), whereas in the second year, the highest amount of thymol was in G. mosseae×D4 (61.97%). This study showed that with the use of mycorrhizal fungi, even in conditions of water shortage, S. sahendica produced more essential oil with a higher percentage of thymol. With the use of mycorrhizal fungi, the essential oil can easily be increased and the number of compounds changes.
