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Showing 33 results for Jahani


Volume 1, Issue 1 (11-2009)
Abstract

adopted here is Social Distance Theory. According to this view, the more social distance among people the less they influence each other. From this viewpoint an increase in social distance among kinsfolk leads to a decrease in mutual influence and this, in turn, affect the emigration tendency. This study is aimed at the investigation of the relationship between kinship solidarity and emigration tendency among educated people. The theoretical framework Based on this theoretical foundation, we have suggested that 4 main variables, the size of kinship network, the strength of kinship relationship, the frequency of kinship relationship, and the profundity of kinship relationship, have negative influences on educated people’s tendency to emigrate. A sample of social sciences and electrical engineering students of the University of Tehran has been surveyed and the empirical data have been analysed both in description and explanation levels. The results indicate that all of the above mentioned variables affect emigration tendency negatively and significantly. Also, our findings suggest that, generally speaking, a negative correlation between the above independent variables and dependent variable of emigration tendency is predictable. In particular, two variables (the strength of kinship relationship, and the profundity of kinship relationship) explain 35% of variances of dependent variable of the tendency to emigrate.

Volume 4, Issue 10 (12-2016)
Abstract

It is in Meydani's Majma Al Amsal that 1000 Arabic proverbs of Al Movaledun have been defined:"Amsal hasn't Arabic identity, they have been borrowed from other cultures to Arabic language".  Meydani has no idea about the identity of Amsal , but whereas commentators believed that Iranian culture has been excessively influenced by revolving Arabic literature, it is lost to approve Iranian origin of Amsal to show Iranian cultural face before Islam through different events. Since there are multiple studies have been conducted to show Iranian identity of Amsal by examining concepts, and vocabularies of Iranian works. This study has tried to compare the concepts of Amsal Movaled and Iranian Tales of Amsal, in order to show the veins of Iranian identity in Amsal, because, Iranian culture and literature show the tales which conclude to those of Movaled proverbs, therefore, there is no doubt on their origins. While Meydani believes that all of the tales of Amsal were quoted, there is no tale to support the documentation of the study, it shows that the tales were not famous in Arabic literature in Meydani career. Such tales of Persian literature and culture are examples of Arabic Amsal in Iranian culture.

Volume 5, Issue 1 (7-2021)
Abstract

Research subject:Well-designed plastic foams, with respect to their cell density and cell size, open-or-close cells, and the cell uniformity, compared to their counterpart unfoamed plastic parts, beside of having the advantages of less material consumption, dimensional stability, better processability, and a higher surface quality, they can have superior mechanical and physical properties, including strength to weight, impact strength, thermal and dielectric properties. The temperature distribution in the different zones of the extruder, the qualities and quantities of the nanoparticle additives and their dispersion in the polymer matrix can have significant effect on the mechanical properties of the produced foams by the extruder.
Research approach: In this study, using an extruder, MA-g-polypropylene microcellular foams, containing 3, 7 and 9 wt% of nano-clay particles, were produced under three temperature arrangements on the extruder and the material and the processing effects on the mechanical properties were investigated.  
Main results: The result of this investigation shows that adding of nanoclay improves the mechanical properties of MA-g-PP.s foams. As an example, the results show that the sample with 7 wt% of surface modified nanoclay, owns about 10% higher impact toughness compared to the samples produced without nanoclay. Also for the same samples a rise of about 5% was recorded in Young's modulus. The microstructural studies of the produced foams by scanning electron microscope (SEM) show that adding of nanoclay can result on more foam uniformity and smaller cell size. In this study, the smallest average cell size (87.5 μm) and the lowest density (0.3 g/cm3) were recorded for a sample with 7wt% nanoclay.

Volume 9, Issue 4 (3-2020)
Abstract

The purpose of this study was to identify and evaluate the current status of organizational barriers affecting the implementation of strategy in public universities. For that reason, a multi-study design was used by a combination of review scoping, a qualitative case study and a survey. At the first study, we used review scoping, and analyzed studies in strategy implementation. The studies were selected with purposeful sampling from the scientific databases. At the second study by using a qualitative case study, views of 15 managers of Shiraz University were considered through semi-structured interviews and then data were analyzed using thematic analysis technique. Likewise, at the third study and the evaluation section, the status of key barriers to effective strategy implementation in the top five universities in the country has been assessed by using a survey method. Findings of the study indicated that numerous organizational barriers including academic leadership, the nature of strategy, academic culture, financial resources, technology, communication, strategy monitoring, structure and human resources in the public universities that have affected Strategy Implementation. The results also revealed that Academic cultureat Tehran University and Shiraz University,structureat Amirkabir UniversityandSharif University,and human resourcesat Science and Technology University,were the most important barriers to strategy implementation.


Volume 10, Issue 1 (7-2020)
Abstract

This paper focuses on the issue of decision making in context of uncertainty and in particular on decision making in innovation and knowledge-based Firms. Decision making in uncertain conditions has many complications that make it difficult to rely solely on analyzes and common models in decision making. Meanwhile, the need to consider alternative methods, especially in the real environment of decision making, is felt. In this research, with a descriptive approach, the model of this type of decision is specifically defined in knowledge-based firms with a quantitative method and structural equation modeling. Statistical analyses were performed on 320 researcher-made questionnaires containing 77 items. Smart PLS software was used for modeling. The obtained model shows that time and information categories play a significant role in creating uncertainty. This uncertainty ultimately leads to the decision-makers' reliance on intuitive decision-making. Underlying conditions and interventions include environmental turbulence, rivals, market changes, technological changes, changes in environments, experiences, education, curiosity, and patterns of mental patterns effect on intuitive decisions that themselves include improvements in speed and accuracy of decision making, creativity, satisfaction and performance of the company.

Volume 12, Issue 4 (Fall 2024)
Abstract

Aims: The absorption of atmospheric Carbon dioxide for Carbon sequestration plays a vital role in regulating the climate. This study aimed to economically evaluate Carbon absorption and Oxygen supply  in Kerman Province using ecosystem service modeling.
Materials & Methods: Terrestrial Carbon storage was assessed using InVEST software, considering aboveground biomass, belowground biomass, soil, and litter/ dead organic matter. Oxygen supply in the ecosystem was also calculated based on Carbon relationships. The economic valuation of Carbon and Oxygen supply was determined using the social cost of Carbon dioxide and replacement cost, respectively.
Findings: In 2021, Kerman Province was estimated to sequester 6,896,182.89 t.y-1 of Carbon and produce 18,481,770.36 t.y-1 of Oxygen. The economic value of Carbon sequestration and Oxygen supply in the Province was calculated at 354,325,877 and 1,686,461,545 $.y-1, totaling $2,040,787,422 in 2021.
Conclusion: The economic valuation of Carbon sequestration and the Oxygen supply spatially demonstrate the multiple roles of vegetation cover in the economy, which help maintain and restore it. Economic valuation maps of studied ecosystem services have comprehensive  land management and planning applications. Furthermore, they underscore the importance of incentives for long-term Carbon storage to encourage sustainable practices. 


Volume 12, Issue 6 (January & February 2022 2021)
Abstract

This article investigates the role of Conceptual Metaphors of 3 behavioral economics biases, including Irrational Evaluation, Labeling, and Replacing market values with social values on Willingness to Pay (WTP) and Willingness to Accept (WTA) of Participants. To extract experimental, conceptual metaphors, the results of field studies were checked on a group of 30 participants in the first phase. In the second phase, we used the semi-pilot method on 30 other participants through 2 stages for investigating conceptual metaphors. Analysis of variances showed that that the conceptual metaphors used in this article do not influence Willingness to Pay and Willingness to Sell. However, in Willingness to Pay status, among other biases, the impact of irrational evaluations conceptual metaphors has stronger effects, whereas, in Willingness to Accept status, replacing market values with social values is stronger than other biases. The results of this research showed that three mentioned behavioral principles that were implemented through conceptual metaphors, couldn't influence buying or selling decisions of participants significantly, but the efficacy of these behavioral principles were different in buying and selling decisions.
1. Introduction
Cognitive linguistics is a new school of linguistics that emerged in the early 1970s due to objections to formal linguistic approaches in Chomsky's views. Cognitive linguistics, like other types of linguistics, studies language and tries to describe the systematics, structure, and function of the language system. One of the most fundamental concepts in cognitive linguistics goes back to conceptual metaphor. Conceptual metaphors mean recognizing one domain through the characteristics of another domain. A simple definition of conceptual metaphor is that "conceptual domain A is conceptual domain B". The conceptual domain itself is any coherent organization of experiences. In this regard, one of the interdisciplinary approaches that has received much attention today is the focus on cognitive linguistics through conceptual metaphors in other areas. It seems that by using conceptual metaphors and examining their effect on perception, judgment and reasoning of individuals, a deeper understanding of cognitive processes can be achieved.
Accordingly, and according to previous research that shows that conceptual metaphors can subconsciously affect the way of thinking of people in various fields, in this study, the role of conceptual metaphors in the background of behavioral economics was investigated. The reason for choosing behavioral economics over neoclassical economics is the objections to the two main pillars of neoclassical economics, "The emphasis on individual rationality and General equilibrium". Individual rationality means that in neoclassical economics it is assumed that people do not include emotions in their decisions, while behavioral economics is based on anthropological studies with psychological methods based on the inclusion of emotions in economic decisions.
 This article examines the effect of conceptual metaphors on the rules of behavioral economics. For this purpose, with reference to cognitive linguistics, we introduce some rules of behavioral economics in the form of conceptual metaphor theory and then in a quasi-laboratory study, we examine the effectiveness of presenting behavioral economics rules through conceptual metaphors in statistical form. In the first phase of the research, we select conceptual metaphors related to the three behavioral rules of irrational valuation, labeling and replacing market values ​​with social values. Then, in the form of the fourth hypothesis, we examine the effect of the relevant conceptual metaphors on the willingness to pay and the willingness to Accept as two factors representing economic decisions.
Research Hypothesis instead of questions
 (s)
Hypothesis 1: Conceptual metaphors related to the best examples of goods in this paper affect the implementation of the behavioral rule of irrational valuation.
Hypothesis 2: Conceptual metaphors related to femininity labeling used in this article, affect the implementation of the labeling rule.
Hypothesis 3: Conceptual metaphors related to social values ​​used in this paper, affect the implementation of the rule of replacing market values ​​with social values.
Hypothesis 4: The use of conceptual metaphors in implementing the rules of behavioral economics considered in this paper (irrational valuation, labeling and substitution of market values ​​with social values) affects the willingness to pay (WTP) and willingness to receive (WTA) of the test subjects.
 
2. Literature Review
The main reason for studying cognitive linguistics is the assumption that language expresses patterns of thinking. Therefore, the study of language from this perspective is the study of conceptualization patterns. In this approach, language is a window to cognitive function and through language, the nature, structure and organization of thinking and mental ideas of individuals can be studied (Evans, Green, 2006). In cognitive linguistics, language is a tool for organizing, processing and transmitting information (Dehghan et al., 1399). One of the most fundamental concepts in cognitive linguistics goes back to conceptual metaphor.
Conceptual metaphor has been extensively studied in linguistic texts but recently, cognitive linguistics has taken a new direction and is examining conceptual metaphors and their role in other sciences as well.
Among these studies are researches that have examined conceptual metaphors in economics. There are two general approaches to the introduction of cognitive linguistics into economic discourses: The first approach is that linguists try to identify the dominant metaphors used in these texts by examining the main and fundamental books of economics in order to find out what metaphors in the foundation of economics is used to provide insight to economics students, and another approach is for linguists to try to show the results of applying these metaphors in practice by selecting up-to-date corpus of economic texts and extracting the dominant metaphors used in them. In view of the above, in order to conduct a joint research between cognitive linguistics and economics with a forward-looking view, in this study, we examined the role of conceptual metaphors in representing the rules of behavioral economics. Before presenting the report of the present study, we will first explain why behavioral economics was chosen as well as its basic foundations.
 
2.1. Why choose behavioral economics (negation of neoclassical economics):
 The main feature of neoclassical economics is its commitment to the theory of rational choice. This practice assumes that people behave in the way they should. If we want to argue according to the neoclassical economics assumption, one hundred percent rational people should not be influenced by emotions. However, financial decisions are generally subject to multiple biases (Guastello, 2016).
       Behavioral economics, in fact, came into being by violating the basic hypotheses of neoclassical economics based on the rationality of individuals and the cumulative equilibrium of the market. From the perspective of behavioral economics, individuals are not always rational, but their irrationality is not without rules but with recognizable rules (Walliser, 2008; Bourgine & Nadal, 2004). At the same time, prices are not simply derived from the intersection of supply and demand in the market, but the price that the consumer is willing to pay may have been completely manipulated by the supplier. Findings of behavioral economics in the field of irrational behavior as well as the way prices are set in the market are the same principles and rules of behavior, such as the effect of ownership, labeling and deterrence (Ariely, 2008). Behavioral economics, in fact, seeks to achieve a more accurate study and prediction of consumer behavior by guiding these rules. In order to get acquainted with behavioral economics, it is necessary to introduce some of its rules:
 
3. Theoretical framework
3.1. Rules of Behavioral Economics
A) Irrational valuation
People seldom consider the absolute and independent value of goods and services in their choices. There is no tool within humans to measure the value of options. Rather, we focus on the relative value of one thing over another and estimate value in this way (Ariely, 2008).
B) Difference in look - labeling
 Expectations also shape the headlines. One example is how to classify information in order to predict experiences. The brain cannot evaluate any new situation from scratch, and grouping or categorization helps the brain a lot in the meantime (ibid).
C) Social relations and market relations
We live in two worlds at the same time. One is a world in which social norms prevail and the other is a world in which market norms prevail. Social norms include friendly demands that people make (ibid).
In view of the rules of behavioral economics presented above, in this study we explored whether it is possible to represent the rules of behavioral economics through conceptual metaphors.
 
3. Methodology
This research was designed and implemented in two phases as follows.
 
4.1. Phase I subjects
This experiment was performed in two separate phases. Thus, the results of the first phase were indicative of the materials of the second phase of the experiment. Participants in the first phase initially consisted of 30 female students (because gender affects the dependent variable in the form of an independent variable of conceptual metaphors of labeling bias) studying in academic disciplines other than economics between the ages of 18 and 35.
 
4.2. Tools and process in the second phase of testing
In the second phase of the research, the conceptual metaphors selected from the first phase were used in three ways to prepare the main experimental materials.
 
4.3. Design of the second phase of the experiment
The method of designing the test materials was that the C-Sharp software was used to design the tests in order to be able to view the goods, specifications and also their prices along with the possibility of selecting the price desired by the subject by clicking on the Yes or No option for each price step.
 
4. Results
Finally, the study of hypotheses one to three of the present article on the effect of conceptual metaphors in implementing the behavioral rules of irrational valuation, labeling and replacing market values ​​with social values ​​showed that these three hypotheses are rejected by univariate analysis of variance but the forth hypothesis was not rejected.
The reasons might be as follow: The first category of reasons included the method of selecting our conceptual metaphors in the first phase, as well as the way in which they were explicitly displayed at the beginning of the introduction of the goods. At the same time, considering the achievement of examining the fourth hypothesis that conceptual metaphors related to irrational valuation are more effective in the task of purchasing and conceptual metaphors related to replacing market values ​​with social values ​​can be used in future research in these two areas to produce conceptual metaphors. He acted in a different way.
 
5. Discussion
In this study, we tried to find out whether it is possible to implement the three rules of irrational behavioral valuation, labeling and replacing market values ​​with social values ​​through the use of related conceptual metaphors. No further study has been done on the application of conceptual metaphors in behavioral economics. Examination of Hypotheses 1 to 3 of the present article on the effectiveness of conceptual metaphors in implementing behavioral rules of irrational valuation, labeling and replacing market values ​​with social values ​​showed that these three hypotheses are rejected. The reasons for rejecting these three hypotheses can be examined in two areas: First, the way our conceptual metaphors are selected in the first phase does not affect their Maximum Payout (WTP) and Minimum Receipt (WTA) decisions, respectively. It has been traded in assignments, and thus it can be stated that choosing different conceptual metaphors in this field in different ways can bring us different results. At the same time, in this area, the use of our conceptual metaphors explicitly at the beginning of the introduction of goods may have made the subjects aware of our purpose and has caused resistance to changing the decision to buy or sell. The second reason that can be stated to refute these three hypotheses could be that for our subjects, only purely technical information of the goods was important in the decision to buy and sell, and the sentences we used at the beginning to introduce the goods with metaphors, has had no effect. Examination of our fourth hypothesis on the effectiveness of conceptual metaphors related to the three types of irrational valuation bias, labeling and replacement of market values ​​with social values ​​showed that this hypothesis is not rejected, while the post hoc test showed that conceptual metaphors are most effective in buying when being related to irrational valuation, and while in the case of sales, the most effective were the conceptual metaphors related to the replacement of market values ​​with social values, while the conceptual metaphors related to labeling were not significant in this area
 
6. Conclusion
our results show that in order to influence the rules of behavioral economics through conceptual metaphors, one must either use another method to extract conceptual metaphors or introduce conceptual metaphors implicitly rather than explicitly into the economic presentation of goods. At the same time, the greater effectiveness of conceptual metaphors of irrational valuation in the task of buying and the effect of conceptual metaphors of replacing market values ​​with social values ​​in the task of selling can be promising. And therefore could be further explored in future research.

Volume 13, Issue 3 (4-2023)
Abstract

Most strategic programs assume the future using various methods, and develop a static program based on trend extrapolation from a single future that provides acceptable results in a small set of possible futures. If the future turns out to be different from the assumed ones, the program may fail. In addition to the high uncertainty in predicting the future, planning conditions also change over time. To address this issue, this study seeks to design a model for developing adaptable strategies that can both provide satisfactory performance in multiple diverse futures (Robustness) and adapt to new conditions. The foundations of this research are interpretive, the approach is qualitative, and it is a developmental-applied study. In this study, the literature on developing strategies under uncertainty is examined using the meta-analysis method. Accordingly, after reviewing the literature, 39 concepts (themes) and 10 elements were extracted. Finally, using the identified elements and concepts and the literature of the study, the final model for developing robust adaptable strategies under uncertainty was designed.

Kamal Jahani, Masoud Dehnad,
Volume 14, Issue 4 (7-2014)
Abstract

Hydraulic engine mounts isolate the structure of the vehicle from powertrain vibrations and also prevent excess motions of the powertrain due to shock excitations. In this paper, dynamic stiffness of a hydraulic engine mount in low frequency range (shock frequency range) is predicted using modal test data and three-dimensional finite element model through an iterative model updating procedure. The implemented model encompasses elastomeric material’s nonlinearity, fluid-structure-interaction and internal resonances of mount. Mesh morphing technique is used to model the fluid-structure-interaction. The results showed that the introduced procedure can successfully predict the shock isolation behaviour of the hydraulic engine mount.
Mohammadreza Asgharzadeh, Kamal Jahani, Arman Kianpoor, Morteza Homayoun Sadeghi,
Volume 14, Issue 15 (Third Special Issue 2015)
Abstract

In recent years,the need for low power electronic circuits like sensors and wireless systems, has been considered by many researchers.Excessive weight, limited lifetime of the batteries and also having problem in replacing them, are the main reasons for harvesting energy from ambient vibrations. Among the various sources of environmental energy, mechanical vibrations, has gained popularity due to the availability. Among the different methods of ambient vibration energy harvesting, piezoelectric method, is one of the good ways to harvest energy due to the favorable effects of electromechanical coupling. The most common means of harvesting energy from vibrations, is a unimorph or bimorph cantilevered beam. In the present paper, electrical energy harvesting from Euler-Bernoulli trapezoidal cantilevered unimorph beam with base excitation using distributed parameter method has been considered. First, equations of motion analytically obtained and then using Assumed modes method(for rectangular beam), system’s natural frequencies is calculated and output voltage, current and power diagrams are presented. For verifying results, presented voltage, current and power diagrams for trapezoidal configuration close to rectangular configuration that it’s results are published in references, will be compared. Then, functional parameters for trapezoidal energy harvester, with resistance value changes for energy consumer has been analyzed.

Volume 15, Issue 61 (12-2018)
Abstract

One of the most important principles of the postmodern world is to pay attention to the principle of "indeterminacy." Postmodern writers, using the techniques of this principle, have shown that reality is more than building, and this is what we are giving to that meaning and being. It can be said that the principle of indeterminacy in Persian literature was written by Mohammad Reza Kateb in the publication of the "pasti" novel Practically applied. In this novel, the author is surprisingly using techniques such as "contradiction, the plurality of personality identities, behavioral deconstruction of characters, the gender change of characters, ambiguity, short-circuiting, and also linguistic-level practices, such as the use of factual expressions in the context of appeals, submissions, and Epistemic, object oriented orientations, deliberate decay in the rhetorical sequence of sentences, the use of arbitrary command structures, the use of linguistic games at the narrative level, the use of techniques such as genre contradictions, the use of story styles in the story, nameless names, ruptures, and multiplicities This article is intended to show the unknown world of " indeterminacy " in the "pasti" novel, which is undoubtedly one of the most prominent novels of the eighties.

 
Kamal Jahani, Parisa Aghazadeh,
Volume 16, Issue 4 (6-2016)
Abstract

Employing piezoelectric systems is one of the suitable methods for harvesting energy from mechanical vibrations available in the environment. In this work,single degree of freedom model for cantilever beam with piezoelectric layer is considered. Simulation contains nonlinear coefficients like: stiffness, damping and coupling coefficient. Governing system of equations is solved by multiple scales method. First with assuming one term in approximate response, the effects of all nonlinear parameters on frequency curve are investigated. Results show that assuming only one term in response evaluates the effect of nonlinear damping correctly. Increasing this coefficient leads to reduce the range of excitation frequency and maximum harvested power. But one term assumption couldn’t assess the effects of nonlinear stiffness and coupling coefficient logically. In this case, the peak of frequency response curve is independent of nonlinear coefficients. So for obtaining accurate results assuming at least two terms of response is necessary. Results show increasing nonlinear stiffness coefficient increase the maximum harvested power and the range of excitation frequency. The effect of nonlinear coupling coefficient is decreasing the maximum power because this coefficient increases the stiffness of the system.

Volume 16, Issue 7 (Supplementary Issue - 2014)
Abstract

The objective of the present study was to investigate the effect of different doses of some 7 natural semi-arid medicinal plants’ essential oils on in vitro ruminal digestion and fermentation patterns of a mid-forage (alfalfa hay: concentrates, 1:1) diet. Treatments consisted of either basal diet alone (control) or added with 35, 70, 140 or 280 µl L-1 of coriander, oregano, caraway, cumin, cinnamon, pistachio hull and thyme essential oils, incubated for 24 hours at 38.7ºC. The essential oils of cinnamon and pistachio applied as 280 µl L-1 and thyme applied at 140 and 280 µl L-1 caused a decrease in DM disappearance as compared with control. Thyme and pistachio essential oils (used at 280 µl L-1) resulted in a decrease of NDF disappearance, while caraway (70 µl L-1) and cumin (140 µl L-1) resulted in an increase in it (14.8% and +18.2%, respectively). Relative to control, the essential oils applied, did not significantly affect the medium N-NH3 concentration (except thyme at 140 and 280 µl L-1), pH (except thyme and cumin essential oils, 6.41 and 6.22 vs. 6.3, respectively), gas produced (except thyme at 280 µl L-1) and Feed Fermentation Efficiency (FFE). Relative to control, addition of all the essential oils resulted in a decrease of CP disappearance and CH4 (except for cumin) production as Mm-1 incubated. Findings revealed that these essential oils may allow manipulation of rumen microbial fermentation.
Omid Jahanian, Atiyeh Mihandoust, Hamid Hassanzadeh,
Volume 17, Issue 6 (8-2017)
Abstract

Jet engines working near the ground, with low speed and high thrust can experience flow separation between ground and inlet which would lead to vortices, called Ground Vortex that have harmful effects on engine performance and can disrupt integrity of inlet flow. Deep understanding of the physics of this phenomenon could omit the injuries of foreign objects damages, engine surge, compressor stall, and fan vibration. In this study, the ground vortex formation near the inlet air duct of an aircraft engine is investigated using computational fluid dynamics. Simulations are performed for a 1:30 scale. The fluid flow is assumed to be compressible, three-dimensional and steady.The k-ω SST model is employed for incorporating turbulent characteristics. After mesh study, the boundary of Vortex or No-Vortex for results of this study compared with a theoretical and an empirical correlation by Murphy which showed good agreement. Moreover, despite free stream existence, decreasing non-dimensional velocity ratio causes the movement of vortex core and by approaching to the critical non-dimensional velocity ratio; the ground vortex would gradually disappear. For U^*= 33,44,66,132 ground vortex is formed, but for U^*=26.4 ground vortex disappears. The computational method has subsequently been applied to configurations that are difficult to test experimentally including headwind flows. According to this study, the formation of the vortical flow field permanently affects the total pressure distortion on the engine fan face. In this paper, DC60 is calculated under headwind condition. These coefficients are 0.39, 0.391, 0.447 and 0.3957 at U^*=33,44,66,132 respectively.

Volume 17, Issue 109 (March 2021)
Abstract

Among legumes, lentil is very rich in protein and is called the meat of poor people. In this study physicochemical, nutritional value and antioxidant properties of two cultivars of Iranian black and green lentils, including moisture and volatiles, total ash, total fat, protein, crude fiber, carbohydrate, measurement of total antioxidant activity and carotenoids content were investigated. Obtained results show that, green lentil contains a higher amount of moisture and volatiles (6.72 g/100g) and carbohydrate (59.34 g/100g), in comparison black lentil had a higher amount of ash (mineral element) (3.66 g/100g), crude fiber (7.40 g/100g), fat (1.95 g/100g), protein (26.02 g/100g) and higher antioxidant activity based on DPPH (IC50= 2408.8 mg/L) and FRAP (concentration of Fe2+ ion= 0.4 mM) experiment. The carotenoid content of black lentil was determined 0.024 μg/g and was higher than green lentil (0.011 μg/g). So it can be said that, despite the advantages of black lentil over green lentil, it remains unknown nutritionally, and it seems very appropriate both economic and agricultural recommending people to consume and to put up black lentil in their diet, with regard to rainfed of lentil and dryland cultivation source in our country.

Volume 19, Issue 2 (8-2015)
Abstract

Attitude to the organizations has changed over the time. A time, the organizations have been considerd as closed systems that had no interaction to their environment. When the system perspective was introduced, attiude to the organization changed, too. At the same time, organizations have been considered as open systems that interact to their environment. While, the organizations acted in an industry and todays, considering to increasingly changes that have been arised in the business environment, the industries boundries have been disappeared greatly. According to James Moore (1993), todays, organizations act in the ecosystem that different business from diverse industries interact each other and their survival increasingly dependent on each other. These concepts were be described well in the business ecosystem approach. Business ecosystem approach has been emerged in the result of environmental changes in the recent decades. The necessary of this approach apployment is making the changes in the mindsets that look at business world with a new attitude and the basic principles demonstrate the mindset changes. This paper is an overview/analytical paper and it's purpose is explaining the basic principles based on analyzing the world business changes in the recent decades. Recognizing the basic principles is one of the success necessaries at the present time.
M. Mousazadeh, K. Jahani, M. Abdollahi,
Volume 19, Issue 5 (May 2019)
Abstract

The aim of this paper is identifying the parameters of for a double-ended magnetorheological damper with different sizes of iron- powders suspended in magnetorheological fluid. There is not any published work in literature about identification of parameters of spherical iron particles with different particle diameters in magnetorheological fluids. Hence, in at first, two different magnetorheological fluids with different diameters of iron particle and same volume percentage are prepared. Then, using a double-ended magnetorheological damper, dynamic displacement tests with harmonic excitation in different frequencies and using different electric currents are conducted. The parametric Spencer model is selected for modeling the damper and identifying its parameters. 10 parameters of this model are identified, using nonlinear least square solver and implementing for damper, using two different magnetorheological fluids in different frequencies and different electric currents. The appropriate polynomials are extracted for parameters that have systematic trends with increasing electric current. experimental hysteresis curves in different electric currents, excitation frequencies and different fluids, it is to assess the capability of Spencer model in regenerating the experimental counterparts. The comparisons of the hysteresis curves obtained from with identified parameters by the experimentally achieved counterparts show that this model has adequate compatibility with experiments in predicting force-velocity hysteresis curves. However, the implemented model has not enough success in predicting the force-displacement hysteresis curves, especially in sharp ends of the curves and force delaying regions.

M. Mousazadeh, K. Jahani, S.s. Samadani Aghdam,
Volume 19, Issue 9 (September 2019)
Abstract

In this paper, the effects of particles size of Magnetorheological Carbonyl iron powder on damping force and energy dissipation capacity for a Magnetorheological double ended type damper is investigated experimentally. Despite of the considerable researches on the effects of particles size on the viscosity of Magnetorheological fluids, sedimentation of fluids and electromagnetic field intensity in damper, there is no a published work about the effects of iron particles size on the damping force amplitude and energy dissipation capacity of double-ended Magnetorheological damper. Therefore, in the present research, two different Magnetorheological fluids were prepared with the same volumetric percentage of % 35 from two different sizes of Iron particles i.e. 40 µm and 63µm and filled into a double ended type damper. The double-ended damper had three electric coils and was tested in different frequencies, different electric currents and 15 mm displacement stroke. The effects of Magnetorheological fluid particles on produced damping force and energy dissipation capacity were analyzed by extracting force-displacement and force-time curves from experiments. The results showed that the maximum amplitude of damping force is increased with increasing the applied electric current on the damper and the amount of this force for fluid with 63µm particles size is slightly higher than that for the fluid with 40µm particles size. However, the energy dissipation capacity of the investigated damper in all excitation frequencies with the all applied electrical currents for fluid with 63µm particles size was considerably higher than that for fluid with 40µm particles size.

F. Imani, K. Jahani,
Volume 19, Issue 10 (October 2019)
Abstract

This study aims to extract the dynamic parameters of a viscoelastic material sample. The mechanical model considered for material is the standard linear solid model. To extract the parameters of the model, first, a sample of the polymer was made. Then, it was subjected to a constant initial value and pressure were measured over time. Then, using the governing relations of the standard linear solid model, by comparing theoretical and experimental relaxation functions, the dynamic properties of the material, such as storage and loss modulus, and its damping property in terms of frequency. To investigate the effects of time passing on the dynamic mechanical properties of the material, the studies were repeated at a different time, which was ten times more than the first study. Also, the effects of constant strain amplitude on the dynamic mechanical properties and damping characteristic of the sample were investigated with three different levels of strain. These values the relaxation function in the first test for the displacement of 2 mm were E(0)=523177.2 N/m2  and after 70 days this value was equivalent to E(0)=666060.8 N/m2. In the same test, the values of the relaxation function for the first test are equivalent to E()=458717.9 N/m2 and in the second test, the value is E (∞)=573029.7 N/m2 Also, the results show that, in smaller constant strains, the efficacy of the material is greater in energy dissipation. In addition, the intrinsic parameter of the Young Modulus is obtained in the experimental estimate of 0.89 MPa.

Alireza Ehsani, Kamal Jahani, Adel Pourtaghi,
Volume 21, Issue 5 (May 2021)
Abstract

Nowadays, torsion springs are used widely in aerospace equipments. In most of gravity gradient booms and some of solar panel extruders, torsion springs plays an important role in expanding these mechanisms.  Since these mechanisms are constantly exposed to severe thermal gradients during orbital circulation and because of sensitivity of these mechanisms, it is important to identify the behavior of their elements under temperature variations. Therefore, in this study, the effect of temperature and its variation on these springs and their performance are investigated analytically and experimentally. To investigate the torsional behavior of the spring, an specific test setup is designed and constructed. This test train includes power transmission, temperature control chamber, temperature controller and torque meter. Torsion springs are selected from hard drawn spring steel. At the temperature range of  to  ,the effect of temperature variation on the produced torque due to different forced torsion angles are investigated. As well as the spring constant variation with temperature is obtained and compared with analytically obtained data. The obtained results validate the consistency and accuracy of the analytical modeling and the applied experimental test train and procedure.

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