Showing 30 results for Tahmasbi
Volume 0, Issue 0 (ARTICLES IN PRESS 2024)
Abstract
The Oriental hornet, Vespa orientalis L. (Hymenoptera: Vespidae) is one of the most important and serious enemies of honeybees. In this study, the annual population dynamics and daily activity rhythm of Oriental hornet were examined, based on the number of adults trapped in an apiary located in Ahvaz (southwest of Iran) during a period of two years (January 2021 to December 2022). Samplings were performed using the box traps available in the market. The bait used in the traps was fresh chicken liver, with the traps checked daily in four time periods. The results revealed that the first overwintering queens (gynes) emerged in March and two population peaks of newly emerged hornet workers occurred during the year, one in July and the other in October. In late November and early December, no adult hornet was trapped. The daily activity rhythm of adult hornets was observed mostly during 9 - 12, almost twice as much as in the afternoon period (12 - 15). The lowest activity was recorded in the evening period and night (6 pm - 9 am). During both years of sampling, the seasonal abundance of adult hornets displayed a significant positive correlation with air temperature and a significant negative correlation with relative humidity. By comparing the result of our findings with other studies performed in the same and different climate zones, it can be hoped to present effective methods to control the population of V. orientalis, especially in areas that have extensive beekeeping.
Volume 0, Issue 0 (in press 2024)
Abstract
Accurate analysis of bitumen behavior as a viscoelastic material and its natural phenomena such as aging are important issues in pavement engineering. Therefore, controlling the low and high temperature properties of bitumens is essential to prevent low temperature cracking and common high temperature distress in order to provide proper service throughout the pavement life. In this study, the aging phenomenon and its effects on the mechanical properties of bitumens were simulated using the Superpave method, namely the RTFOT method for short-term aging and the PAV method for long-term aging. In order to investigate the effect of repeated PAV cycles on the properties of bitumens, three types of bitumen with different penetration degrees of 40-50 (PG70-16), 60-70 (PG64-22) and 85-100 (PG58-28) were selected and three samples of each were subjected to one to three PAV aging times. The beam shear rheometer (BBR) test was performed at three temperatures from 0 to -12°C and the dynamic shear rheometer (DSR) at seven temperatures from 46 to 82°C. Based on the results obtained, the high temperature performance of the bitumens increased by a maximum of three grades and their low temperature performance increased by a maximum of two grades. In other words, the grading of the triple bitumens, after three times of PAV, became 82-4, 82-10, and 70-16, respectively. Also, the relationship between the high temperature performance properties of the aged bitumens and their chemical changes at different times of aging was investigated and their changes were examined to show the correlation between these properties. The results showed that the high temperature viscoelastic properties and the chemical aging index of the different bitumens had a strong linear relationship with a coefficient of determination (R2) of more than 0.9.
Volume 1, Issue 1 (Spring 2020)
Abstract
This study aimed to determine the effect of selected physical activities on life skills. For this purpose, 80 male students aged 12-15 were selected as available samples. Then, the Beck Physical Activity Questionnaire and Walker Walker Lifestyle Questionnaire were divided into two groups of control and experimental based on their scores. The experimental groups performed the selected exercise protocol for 12 sessions, each for 1.5 hours. After 12 sessions for both groups, a post-test was performed. In order to compare the subscales of accountability, interpersonal relationships, growth and prosperity of the two experimental and control groups, the pre-test and post-test stages of the mixed variance analysis test are used in a 2 × (group) 2 design. A one-way covariance analysis test was used to compare subscales of appropriate nutrition, stress management and exercise and physical activity. All statistical calculations were performed in SPSS software at a significant level of 5%. Given that the role of exercise and physical activity in childhood and adolescence is undeniable in developing social skills, responsibility, happiness, vitality, etc., it is suggested that three sessions per week of out-of-school physical activity be improved. And the development of life skills.
Volume 3, Issue 1 (6-2013)
Abstract
Given the importance of loyalty, this study seeks to test and investigate the effectiveness and mechanism of relationship between factors that influence the e-loyalty in Saman Bank. In this regard, Relationship Marketing Strategy is the independent variable, e-satisfaction and e-trust are the moderating variables and e-loyalty is the dependent variable in the research model. The research population is a group of customers in Tehran who used the internet services of Saman Bank. Two underlying foundations of Relationship Marketing, mutual obligation and communication, significantly affect e-trust and conflict management foundations and competency are highly effective one-satisfaction. However; no meaningful relationship was found between conflict management and e-trust.
Volume 3, Issue 1 (spring 2022)
Abstract
Statement of Problem: Rural landscapes, as continuing cultural landscapes, represent the natural personality of their community over time, landscapes that change under the influence of cultural and natural currents in their context. Human interaction with nature and the continuity of these landscapes have created several outstanding values in rural landscapes that express tangible and intangible values or in other words, its semantic importance. International documents emphasize the need to develop a conceptual framework and identify these values as a key component in the process of conservation of these landscapes, so that any effort to protect and regenerate rural landscapes, in principle, helps to preserve culture and sustainability of a land.
Aims: To identify and categorize the values of rural landscapes in order to regenerate and sustainably protect such environments and transfer their collective knowledge and cultural meanings to future generations.
Methods: This research first defines the concept of cultural landscape and formulates the conceptual framework and position of rural landscape by reviewing international documents and conventions and examining the views of experts. Then, according to the studies, the values in rural landscapes are classified and explained and finally, a model for regenerating and preserving rural landscapes is presented.
Findings: In this study, the values of rural landscapes divided into two groups: natural and tangible values and cultural and intangible values. Natural and tangible values including environmental, physical, economic and educational values, and cultural and intangibles values include cultural, spiritual, social, and recreational ones. Although in some cases, values are a combination of both, so they are very difficult to refine.
Results: Considering the existing values, a model for recreating and protecting rural landscapes has been presented, which in order to coordinate with the change in the prioritization of these values, it is necessary to pay more attention to their dynamic and multifunctional aspects.
Volume 5, Issue 9 (Spring & Summer 2018)
Abstract
The topic of Hyperbole has been taken into consideration in various sciences of Arabic language, but less has been taken into additional verb, especially in the Holy Qur'an. The abundance of Hyperbole in the Qur'an's additional verbs and the semantic delimitations of these sentences and the lack of sufficient attention by translators in translating them necessitates research and review of this subject. In the present research, through the descriptive-analytical method, the challenges of the concept of Hyperbole and its reversal in lower Quran additional verbs have been examined. The purpose of this research is to introduce these challenges and ultimately provide a more accurate translation of the Qur'an. According to the findings of this research, at least three major challenges in this regard can be identified: The multiplicity of meanings of third person verb and the glorification of more famous meanings, the interconnection of the two concepts of "plurality" and " Hyperbole", and mistake in identifying the subject of Hyperbole. Moreover, the study of sample verses in this study shows that the general Persian interpretations and translations have a weakness and inadequacy in the understanding and transference of the concept of Hyperbole of additional verbs in the Qur'an. In addition, the method of analyzing verses in this study reveals that it is not easy to distinguish between the implication of verbs on Hyperbole, and can not be understood solely by relying on the mere meaning of the terms and generalities contained in the mere books on this subject. Instead, it is necessary to interpret the text of the verses and analyze its space using the inner and outer metamorphosis in order to recognize the implication of Hyperbole in the additional verbs of the Qur'an.
Volume 8, Issue 3 (fall 2020)
Abstract
George Gordon Lord Byron,a British poet of 19th century, was heavily influenced by Oriental and Persian literature in his works. The poet’s life coincided with beginning of the “Victorian age”, and “romanticism” style emergence and the beginning of the European literature’s impressionability presentation from Iranian literature and Persian language; hence he is known as an outstanding person and European renaissance’s symbol and among the Persian literature’s impressed ones.
In This research attempt to clarify the “Manfred” Play’s contribution among Lord Byron’s works in Persian literature’s impressionability through library and documentary tools and relying on an analytical and comparative method. The result is that the above work is influenced strikingly by the works of Persian literature and language, Oriental myths and culture in “symbols”, “concepts”, “fantasies” and even “lexical” terms, which are collected due to Byron’s studies in his subconscious. Also research data show that the two categories of “Zoroastrianism” and “mysticism”, in effectiveness of Persian literature, had the largest share which are presented under two total categories: character-making level and
space-making level.
Volume 9, Issue 4 (3-2010)
Abstract
Governments of developing countries typically spend between 15 and 30 percent of GDP. Hence, small changes in the efficiency of public spending could have a major impact on GDP and on the attainment of the development's objectives.
This paper presents a framework where data envelopment analysis (DEA) is used to assess the efficiency of expenditure in education and health sectors. More specifically, this paper assesses efficiency and seeks to establish a link between difference in efficiency level across countries and policy conditions. The data are used for a sample of member states of organization of the Islamic conference (OIC) over the 2000-20005 period.
The findings show that under 5 year old mortality rates, malnourishment prevalence and immunization rates are the main determinants of deficiency in health sector of sample countries. Moreover, enrolment ratio, more specifically in secondary school, is the major factor that affects public spending efficiency in the education sector. In addition, results show that because of international aid programs, on average, countries in Africa are more efficient than those in Asia and Middle East.
Volume 10, Issue 4 (Winter 2022)
Abstract
Travelogues are among the sources of various literary styles that provide important information about the historical, cultural, artistic, and anthropological background of a country through the images recorded by the travelogue, so far as they have a great contribution in the social-historical reconstruction of a country. The simple and stereotyped definition of imagery or imagology, which has an interdisciplinary approach in comparative literature, is the study of another image in one's own literary texts and vice versa, that is, the study of one's own image in other literary texts. The more accurate the view of the travelogue writer is, the more comprehensive the report he presents in his travelogue is whcih increases its credibility. The correct transmission of this information also helps the accuracy of the travelogue. If a writer is not careful in any of these steps, knowingly or unknowingly, he will make a mistake in accurately recording the reports and the truth, or a part of it will be neglected. On the other hand, we cannot ignore the influence of stereotypes and mental sediments of the writer on what he writes. For these reasons, there is not much expectation from literary texts to reveal reality and facts, and in this sense, literary works cannot be compared with facts and scientific studies. Pollack's travelogue; Iran and Iranians includes the description of pictures that Pollock, an Austrian doctor, saw and wrote in Iran. These observations, which go back to the end of the Qajar period during the reign of Naser al-Din Shah, are divided into two general parts: the first part includes the number of people, geography, customs and eating habits, clothing, etc.; the second part includes the government system, the court, and court occasions, diseases, medicine and treatment methods, medicines, etc. Pollak's claim is that he wrote the contents of his travelogue accurately and without bias or mistakes; however, this study revealed that such as claim is not very accurate.
Majid Ghoreishi, Vahid Tahmasbi,
Volume 14, Issue 12 (3-2015)
Abstract
In this paper, dry electro-discharge machining (Dry EDM), one of the newest machining processes which differs mainly from conventional EDM in using gaseous dielectric along with tool electrode rotation, has been studied. Gap voltage, discharge current, pulse-on-time, pulse-off time, dielectric gas pressure, and electrode rotational speed have been considered as effective input parameters. Response surface methodology (RSM) has been used to optimize the machining performance with respect to material removal rate (MRR). Base on the results and analysis of running experiments, it can be concluded that MRR increases by increasing gap voltage, discharge current, the ratio of pulse-on time over pulse-off time, input gas pressure, and electrode rotational speed. There also exists an optimum amount of pulse-on time determined according to the machining circumstances. Also the material removal rate in dry EDM has been improved compared with that in conventional EDM in identical conditions. Keywords: Dry electro-discharge machining (Dry EDM), Gaseous dielectric, Response surface methodology (RSM) Keywords: Dry electro-discharge machining (Dry EDM), Gaseous dielectric, Response surface methodology (RSM) Keywords: Dry electro-discharge machining (Dry EDM), Gaseous dielectric, Response surface methodology (RSM)
Vahid Tahmasbi, Majid Ghoreishi, Moein Taheri,
Volume 15, Issue 13 (Special Issue 2016)
Abstract
Vahid Tahmasbi, Majid Ghoreishi, Mojtaba Zolfaghari,
Volume 15, Issue 13 (Special Issue 2016)
Abstract
Zahra Tahmasbi Abdar, Khosro Lari, Morteza Abdolzadeh,
Volume 16, Issue 13 (Conference Special Issue 2017)
Abstract
Volume 16, Issue 87 (5-2019)
Abstract
Physical and antibacterial properties of ultrasound assisted emulsions from two essential oils (Cuminum cyminum and Oliveria decumbens) at concentrations of 1, 3, 5, 10 and 15% were studied. The results showed that all emulsions were stable after centrifugation. Although the samples were stable after heat-cool cycles, they became unstable at the freeze-thaw cycles. Emulsion samples with concentrations of 10 and 15%, were stored at 45 ºC for 35-days were unstable and became two-phase. Measuring the turbidity of emulsion samples with a spectrophotometer showed that with increasing concentrations of dispersed phase, the emulsion turbidity increased. Both emulsions showed antibacterial activity. But the C. cyminum emulsions showed higher inhibition zones against Escherichia coli, while O. decumbens emulsions represented higher inhibition zone against Staphylococcus aureus. Generally, the inhibition zone diameters of both emulsions increased dose dependently.
Kamin Tahmasbi, Masoud Mahmoodi,
Volume 17, Issue 4 (6-2017)
Abstract
Friction stir extrusion (FSE) is a process based on the heat generated by friction between die and materials in which a sample is produced through consolidation and extrusion of precursor materials such as metal chips. In this paper, the wire samples produced by friction extrusion of aluminum alloy AA7022 chips are investigated. The samples were extruded at different rotational speeds and extrusion forces, and impacts of these two parameters were studied. At first, structural properties of samples were studied using optical microscopy and scanning electron microscopy (SEM). The result showed that the samples produced at higher rotational speeds and lower forces had a far better surface quality and lower surface crack were seen on them. On the other hand, the temperature of process and grain size were increased with rise of rotational speed. The SEM micrographs showed that by changing rotational speed and extrusion force, the amount of adhesion and sintering between aluminum particles change and by optimizing these parameters can decrease wire’s internal defects and pits. In the following, to study mechanical properties, micro hardness and compression tests were used. The values of hardness and yield stress of samples were decreased with increasing rotational speed and increasing the extrusion force to a certain extent caused increase in yield stress of material.
Volume 17, Issue 7 (Supplementary Issue - 2015)
Abstract
Genetic parameters were estimated in a base and closed population of Iranian honeybee colonies. Data were obtained on 500-700 Iranian native population of honeybee colonies (honeybee breeding project in central region of Iran) subject to 9 successive generation of selection. These populations had been selected for honey production, swarming behavior, and defense behavior. Heritability of honey production, swarming behavior, and defense behavior were 0.22, 0.34, and 0.44, respectively. Phenotypic and genetic correlations between honey production with swarming tendency and defense behavior were -0.16, -0.59, and 0.21, 0.48, respectively. Phenotypic and genetic correlations between swarming and defense behavior were -0.52 and -0.67 respectively. The genetic and phenotypic trends of swarming behavior, defense behavior, and honey production in the honeybee colonies during the 1999-2009 were desirable. Lower heritability of honey production and its higher dependence on apiary management and environmental or climatic factors caused lower improvement of honey production in breeding plans.
Volume 18, Issue 2 (3-2016)
Abstract
Limited data exist about the production of extruded linseed as a feed ingredient in farm animal nutrition. The objective of this study was to produce and evaluate extruded linseed mixed with alfalfa hay, pistachio by-products, and sugar beet pulp or corn grain in different proportions of linseed: alfalfa hay: pistachio by-products at ratios of 70:15:15, 70:20:10, 70:10:20, and 80:10:10 for quality parameters and in situ rumen Dry Matter (DM) degradability. Using a completely randomized design, the treatment containing alfalfa hay had higher Extrusion Effectiveness (EE), Water Holding Capacity (WHC), and Angle of Repose (AR), but lower Oil Loss (OL) and Bulk Density (BD) than other treatments (P< 0.05). There were no differences among extruded linseed products with different ratios of linseed: alfalfa: pistachio by-products for EE, WHC, and AR (P> 0.05). The treatment with an 80:10:10 ratio had the highest OL among all treatments and the treatment with a 70:15:15 ratio had lower BD than the others (P< 0.05). The DM degradability parameters of extruded products was affected by the absorbents and the treatment containing alfalfa hay had higher potential DM degradability than other treatments (P< 0.05). In conclusion, extruded treatment with alfalfa hay had the highest EE, oil retention capacity and potential rumen DM degradability compared to other treatments. In addition, extruded linseed product with an 80:10:10 ratio of linseed: alfalfa hay: pistachio by-products had higher OL than the other ratios.
M. Ghoreishi, Mojtaba Zolfaghari, Vahid Tahmasbi, Hamed Heydari,
Volume 18, Issue 5 (9-2018)
Abstract
In orthopedic surgeries, the bone drilling is one of the most important biomechanic processes that has used. ،This mechanical process is very important, sensitive and all-purpose in biomechanical engineering, because its complexity and special conditions. Bone drilling process has advanced by roboots and CNC machin entrance into the realm of orthopedic surgeries. The problematic issue during operation is the high increase in drilling process temprature which leads to the so-called thermal necrosis . It is not clear quality of enfluence of tool rotational speed and feed rate on the temprature and force responses and so it can be seen confilicts among different researcher results frequently. In this paper it is performed mathematical modeling and design of experiments on the input factors and output parameters of bone drilling. The effect of input factors and interaction of input factors have investigated. Increasing rotational speed the temperature increases where as the feed rate behavior is complex because contact duration between drill bit and bone so the increasing temperature take places because the low feed rate or increasing force and friction. In addition increasing the drill bit diameter increases the tempratures. Also the sobol sensitivity analysis method has used to investigate effect of each parameter in which rotational speed, feed rate and drill bit diameter have most effect respectiviely on temperature instantaneously. Also optimization process performed on temperature behavior, hence the minimum temprature is 37 0C when the diameter of drill bit 2.5 mm, rotational speed 500 rpm and feed rate 30 mm/min.
Volume 20, Issue 1 (3-2016)
Abstract
This study has been done to analyze the impact of external social capital on competitive advantages in two categories: the organization and manager’s relations. The dynamic capabilities as mediator, and also some environmental adjustment were used. The research method is combinational, with explorative approach and develop typology model and the research process is formed in three parts: quantitative- qualitative- quantitative. In the first quantitative step, the basic model was designed by literature review. In the qualitative step, the final conceptual model was outlined with deep interviews and further literature review. The reliability and validity of questionnaire was evaluated with different approaches. The questionnaires were distributed in 13th international building fair in Tehran with random sampling, and 352 returned and complete questionnaires were used for quantitative analysis. The findings show the managerial oriented external social capital did not have a significant (meaningful) impact on mediators, except organizational learning. In contrast, the organizational oriented external social capital had a high significant impact on mediators. The competitive intelligence has an important role between dynamic capabilities dimensions. Also the technological turbulence has the most significant impact between moderators. Based on the findings, pay attention to create strong and influential :union:s, focus on organizational goals in relations and continuous absorption of elite and skilled workers are the most important suggestions for the organizations in this industry.
M. Qasemi, M. Sheikhi, M. Zolfaghari, V. Tahmasbi,
Volume 20, Issue 4 (April 2020)
Abstract
Cortical bone milling is used in orthopedic surgeries such as knee replacement, otological, spinal cord, and hip replacement. The cutting forces created by the cutting tool during cortical bone milling in order to control the wear of the tool as well as applying allowable force to the bone to prevent fracture should be controlled. In this paper, the effective parameters in the bone milling including cutting speed, feed rate, cutting depth and tool diameter has been investigated using the response surface method in order to predict the cutting forces. In this method, a second-order linear regression equation can be presented in order to predict the behavior of the bone milling process precisely. Also, Sobel's sensitivity analysis method was used to study the effect of input parameters on the behavior of cutting force. In this research, the behavior of different input parameters and the effect of their interactions on the machining force has been evaluated and analyzed. The components of cutting force were measured and investigated in three directions of feed, perpendicular to the feed and perpendicular to the bone surface. The results show that the mathematical model governing the problem has a proper function within the range of the defined parameters and it can provide a good prediction of force behavior. The minimum cutting force can be achieved in a rotational speed of 1500 rpm, feed of 12 mm/min, tool diameter of 2 mm, and cutting depth of 0.2 mm. Also, about the sensitivity of the force behavior based on the input parameters variation in the range of experiments, the greatest effect was related to the cutting depth with 36.3% of the effect, and feed rate with 28.4% of the effect, the diameter of the tool with 27.5% of the effect and the rotational speed with 7.8% of the effect.
