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In this research, closed-cell natural rubber foams were produced using a single-step compression molding. The effect of carbon black content on morphology, physical and mechanical properties of the foams were examined. Results showed that in this methodology, the foam density was independent of reinforcement percentage, which is a unique characteristic of single-step foams that contrasts with other previous observations. The study of curing behavior of foam compounds showed that the carbon black increasing from 0 to 30 phr increased the crosslink density (CLD) from 6.5 to 8.3*10^-5 mol/cm³, the cure rate from 16.1 to 23.2 (%/min) and the ultimate torque from 5.8 to 10.4 Nm, while, reduced curing time from 9.2 to 5.8 min. The scanning electron microscope (SEM) results showed that the reinforcement acted as a nucleation agent increasing the cell density from 8 N/cm³ to 140 N/cm³ and reducing the cell size from 579µm to 255µm. The increase of reinforcing content in the produced foams reduced the cells size and enhanced the properties of the rubber matrix. Accordingly, the modulus and hardness of the foams were increased by  0.8MPa and 40 shore A, respectively. Results of sound absorption and reflection showed that the rubber foam reflects the sound waves more than 90% and absorbs waves about 10%.

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Background: In this study for the first time terrestrial laser scanning survey was implemented on upland Hyrcanian forest, through which a and new method was applied to automatically extract DBH and tree position as a necessary step for height calculation and fitting the clustering as a circle.
Materials and Methods: Tree height extracted by fixing a cylinder around the trees center. The accuracies of these methods were investigated by field measurement. Among 4 shapes fitting algorithm, Monte Carlo had more suitable result to fitting circle in each height above the ground.
Results: Tree detection rates were 85% for Carpinus betulus and 87% for Diyospyrus lotus with respect to field measurement. R² and RMSE for DBH measurement were 0.98, 2.06 cm for Carpinus betulus and 0.98, 1.26 cm for Diyospyrus lotus. Value of R² and RMSE for height measurement were 0.96, 3.37 meters and 0.93, 3.02 meters for Carpinus betulus and Diyospyrus lotus, respectively.            
Conclusions: The accuracy of DBH by TLS is very suitable, and about the height of trees we extracted underestimated value in comparison to field measurement and that we need to develop more effective algorithms in order to reach more accurate measurement of trees’ height in Hyrcanian forest.

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Introduction
Urban studies thinkers consider citizens' participation as one of the infrastructures for increasing in the capabilities of urban management. In order to citizens' participation to be meaningful and express the main concept of participation, it must be on a local scale and then reach the transnational arena. Neighborhoods, as the most fundamental elements of cities, have a special place in shaping and organizing the affairs of Tehran. With the establishment of the Pahlavi government and the effort to modernize Iran and the growth and increase in the population of cities, the traditional structures of urban life, including neighborhoods, underwent a transformation. The Law of City Associations was approved before the revolution, but it took many years to pay attention to neighborhood life again with the formation and implementation of the city's Islamic councils in 1998. In recent years, the neighborhood has been defined as the center of concentration and connection of urban services - people and municipality - in the smallest structural area of Tehran municipality. This center was chosen in such a way that all the possible capacities of the municipality can be delegated to it, and at the same time, concrete and objective participation of the citizens was directed to it in all areas that can be participated in, and new and up-to-date functions were defined for it. New social theories consider women's participation in sustainable development processes to be essential, and since the field of women's activity is traditionally wider in the fields of family and neighborhood, the local administration has envisioned a special role for women in city affairs and implemented special programs to improve their quality of life. In an environmental approach, women have the ability to play a greater role as leaders or active participants in smaller communities such as urban neighborhoods. It can be said that women play an essential role in local social cohesion. This type of connection is especially necessary to achieve social planning and successful management in multicultural societies. Because experience has shown that women pay attention to the dimensions of the needs of all groups in society and are not limited to the views and desires of powerful and effective members of society and often seek to create bridges over social, cultural and racial divisions as well as incompatibilities in society. That society will lead to a better life.
Research findings
Based on this, the current research tries to investigate the effect of local women's participation in the programs of active organizations (Serai Mahlah) on improving their quality of life. Angeh, Homayun Shahr and Aqdasiye neighborhoods were introduced and selected as examples by the neighborhood management strategic headquarters because of their active role in this matter. In the current research, a survey method was used with the two goals of description and explanation. At the level of description, the goal is to provide information on the level of participation of women in the administration of neighborhood affairs, and at the level of explanation and analysis, the goal is to find the existence or non-existence of a relationship between independent and dependent variables. At the same time, it has been used to compile the theoretical foundations and review previous researches in a documentary (library) way. The statistical population of the research is made up of the women of Tehran's active neighborhoods in the field of participation in the administration of city affairs, and on this basis, two groups of active and inactive women were selected from among the women of these neighborhoods and investigated. In this research, the sample size is 240 tons, which was determined based on Cochran's formula, which is divided into two parts (124 active tons and 116 inactive tons). In the sampling method, there are two important reasons for choosing the neighborhood center, one is that the manager of the neighborhood is a woman, and the other is the introduction by the neighborhood management strategic headquarters as the most active centers in the neighborhoods of Tehran, which are Angeh, Homayoun Shahr, and Aqdasiyeh neighborhoods. Available sampling method was used to select local activists and random sampling method was used for inactive people. A questionnaire was used to collect information. After verifying its validity and reliability in the preliminary stages of the research, the questionnaire was used to collect the required data in the final stage. The results obtained from this research show that the existence of the neighborhood management institution shows that the participation of citizens is recognized as a necessity and need for collective life, and women are not excluded from this as citizens of the society. Sarai Mahalat is active as one of the sub-institutions of neighborhood management, and the use of the services provided in it can have a significant impact on improving the quality of life of women in various dimensions, and the officials are required to provide the necessary conditions to create the necessary infrastructure and facilities in this regard. On the other hand, they should create the necessary motivation in women in different ways so that they also become eager to participate in local affairs (various aspects), because compared to men, women devote more time to work inside and around the house (local area), so they have deeper experiences, knowledge and insight to build the environment around them. According to Arnstein and Hannah Arendt, if women can have an active participation in the administration of local affairs and not just a theatrical participation, they can actualize and realize their potential talents in various fields. It seems that if the participation of women at the local level has positive results (as the results of this research confirm this), it will lead to this fact that women are encouraged to participate at higher levels of society, which will facilitate the development of the country.
Conclusions
In the present study, the impact of the use of services provided in Sarai Mahalat on the quality of life of service users was investigated in different dimensions. At first, the presence or absence of a relationship was measured using Pearson's correlation coefficient, which confirmed the existence of a relationship between women's local participation and the improvement of their quality of life in different dimensions. In the following, the difference between the average scores of the group that used the services and the group that did not use the services was investigated using the T-test, and according to the obtained scores, the hypotheses of the research were confirmed. After that, two-dimensional tables were used to clarify the relationship between dependent and independent variables. The results of these tables show that the intensity of the relationship between local participation with the quality of life and physical health is greater than the intensity of its relationship with economic empowerment.

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Urine production and excretion has been one of the intricate problems investigated in the field of biomechanics. However, the mechanism that transports urine from the kidney into the bladder has not been fully understood. Engineering analysis of peristalsis in the ureter can be helpful in better understanding of function and abnormalities of this organ of the urinary system and also aid in the design of flow aided devices such as valves and stents to remove these abnormalities. In this paper, urine isolated bolus transportation in the ureter was simulated using ureteral anatomical data during peristalsis. Urine pressure distribution in the ureter, shear stress of ureteral inner wall, bolus dynamic deformations during its propagation and the effect of pressure difference Abstract- Urine production and excretion has been one of the intricate problems investigated in the field of biomechanics. However, the mechanism that transports urine from the kidney into the bladder has not been fully understood. Realization of peristalsis in the ureter may be helpful in better understanding of function and abnormalities of this organ of the urinary system and also aid in the design of flow aided devices such as valves and stents to remove these abnormalities. In this paper, urine isolated bolus transportation in the ureter was simulated using ureteral anatomical data during peristalsis. Urine pressure distribution in the ureter, shear stress of ureteral inner wall, bolus dynamic deformations during its propagation and the effect of pressure difference between the kidney and the bladder on the quantity of reflux and efficiency of urine transportation as a result of peristalsis, were investigated. A computational model was presented that used the tools of computational fluid dynamics, Arbitrary Lagrangian-Eulerian formulation, incompressible Navier-Stokes equations and adaptive mesh algorithm in the fluid domain. In the structure domain, it utilized Arruda-Boyce non-linear model and contact condition. The major benefits of this model comparing to previous studies were that the ureteral wall displacements were not pre-determined during peristalsis and luminal pressure variations influenced on it. Finite element equations of fluid and structure were solved using fluid-structure interaction method (FSI) and direct coupling. Results of this research showed that the proximal portions of ureter were under higher magnitudes of shear stress. Moreover, increase of the bladder pressure magnified the quantity of ureteropelvic reflux in the case of dysfunction of ureteropelvic junction, and resulted in a higher peristaltic efficiency transporting ureteral bolus into the bladder.

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Aims: In bone tissue engineering, the scaffold as a supportive structure, plays a vital role. Putting the scaffold in dynamic cell culture, such as perfusion bioreactor, makes the role of mechanical parameters such as shear stress and hydrodynamic pressure more important. On the other hand, these mechanical parameters are influenced by scaffold architecture. In this study, the effects of bone scaffold architecture on mechanical stimuli have been analyzed and their effects on the mesenchymal stem cell fate have been predicted.
Material & Methods: Using the tools of computer simulation, five bone scaffolds (Gyroid, high porous Gyroid, Diamond, IWP, and gradient architecture Gyroid) based on mathematical functions of minimal surfaces were designed and exposed in a simulated dynamic cell culture under the inlet velocities of 1, 10, 25, 50, and 100μm/s. Cell accumulation on the inner part of the scaffold was considered as an 8.5-micron layer. This layer was designed for Gyroid and IWP scaffolds.
Findings: Based on the results, Diamond scaffold showed the most efficient performance from the homogeneity of stresses point of view. In the presence of the cell layer, the von Mises stress was reported as 60 and 50 mPa on the Gyroid and IWP scaffolds, respectively which eases osteogenic differentiation.
Conclusion: In gradient architecture scaffolds under dynamic conditions, there is a gradient in shear stress that causes various signaling in different positions of theses scaffold and facilitates multi-differentiation of the cells on the same scaffold.

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Aims: Health literacy is considered a fundamental ability needed when making difficult health-related decisions. Also, people with nutrition literacy can convert nutrition messages into knowledge and tend to make healthier eating choices. This systematic review aimed to summarize the literature on nutrition and health literacy to enhance the medical students’ knowledge about the importance of health and nutrition literacy.
Information & Methods: In this study systematic review, research articles published in English were reviewed using relevant terms in PubMed, CINAHL, Web of Science, EMBASE, Scopus, and CINAHL databases. The articles were selected based on the inclusion and exclusion criteria, repetition, purpose, and relevance to the topic. Furthermore, the “Consensus-based Standards for the selection of health Measurement Instruments” checklist was used to select and evaluate the reviewed articles.
Findings: A total of 2978 articles were reviewed. Ultimately, 15 articles were approved and included in the study. Six studies were conducted on nursing students, six were on students of pharmacy and other clinical fields, and three studies examined medical students. The average nutrition and food literacy scores were sufficient, whereas the nutrition knowledge score was moderate.
Conclusion: In the reviewed studies, nutrition literacy is evaluated to be at a low to medium level. Most students have insufficient nutrition knowledge.

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Nowadays, Cognitive semantic approach plays an important role in learning second/foreign language. However, a few experimental investigations have applied a cognitive perspective to instructed L2 learning. The main purpose of the present research is comparing impact of cognitive approach to the traditional approach in learning some frequency concepts of the preposition "be" in Persian language. First, different meanings of preposition "be“ were selected from Farhang Sokhan Anvari (2002) and then some sentences and phrases containing this preposition were investigated according to the Farsi Biamoozim (2010) in the middle level. Prior to begging the instruction, 50 non-Persian learners (woman) were selected by proficiency test at Jamee-Almostafa of Mashhad center. This group were randomly divided into control and experimental groups and then, pre-test and post-test was applied between these groups. By using SPSS, comparison of the pre-test in control and experimental group revealed that there isn’t significant difference between prior knowledge of two groups before treatment, whereas the post-test showed that there is statistically significant difference between two groups. The results indicated that experimental group which was under the training of cognitive method showed significant gains than control group who received the traditional training methods.

1. Introduction
Persian Language learning is one of the most complex issues in teaching foreign languages. One of the most important issues in language is teaching and learning prepositions. Rote learning lacks comprehensive analysis of the different senses of prepositions.  Compared to other approaches, cognitive linguistics offers the aspects of meaningful learning (Song, 2013: 1). Cognitive approach to language and grammar is shown a systematic form.  Accordingly, in this paper, we are going to examine the impact of traditional approach compared to cognitive approach in learning different concepts of the prepositions "Be" for non-Persian speakers. So :

1.  According to Toylor and Evans creteria (2003) what's Prototype meaing of preposition "be"?
2. According to Langackers' theory of domains (1987), how we can teach abstract meanings of preposition "be"?
3. What’s different between groups (control and expremental groups) in improvement after teaching preposition "be"?

2. Literature Review
 The present study is concerned with a Cognitive Linguistics meaningful approach to teaching prepositions. This study attempted to examine the impact of cognitive approach compared to traditional approach in learning different concepts of the preposition"Be".

2.1. Theorival researchs
In the interaction between human beings and their environment, human experience is imposed on a structure in terms of natural dimensions of the kind. In some studies (Lakoff & Johnson, 1980; Toyler & Evans, 2003; Langacker, 1987) there are theoretical definitions to explain Cognitive Linguistics and its impacts in teaching language and prepositions.

2.2. Experimetal researches
 Other researches (Song, 2013; Tyler, Mueller & Ho, 2011; Golfam & Yoosefi Rad, 2010;Vahidi, Badamdari 2016) investigated experimental method to teaching different prepositions by Cognitive Linguistics approach. Their findings shows applying cognitive method had significantly improvement in teaching different concepts of the prepositions.

3. Methodology
In this paper, first of all, based on Tyler and Evans' prototype criteria (2003), we have determined the prototype and different meanings of the spatial and prototype meanings of preposition "Be" according to Farhang Sokkan (Anvari, 2002). Finally, sentences and phrases including these prepositions were chosen according to Farsi Biamoozim (2010) in the intermediate level. Data collection, took place among 50 non-Persian learners at Jame-e-Almostafa of Mashhad.  Sample groups were selected randomly, then they were divided into control and experimental groups. Data analysis were estimated by spss (Independent T-Test) in control and experimental groups.

4. Results
The results of the study will enrich our understanding of reconceptualization and learning by a cognitive approach. In this study, we taught the spatial as well as other senses of this prepositions:

Table 1
Table1. Independent t-test in the pre-test of the control group with the experimental group

گروه	mean	Standard deviatin	Levene's test		t-test
			F value	meaningfulness	T value	degree	Meaningfulness
control	58/18	06/2	459/1	249/0	208/0-	24	799/0
exprimetal	85/18	13/3

According to table 1, data analysis in Independent T-Test (comparison of pre-tests in control and experimental groups) displayed that there isn’t significantly improvement between prior knowledge of learners before teaching.

Table 2
Table2. Independent t-test in post-test of the control group with the experimental group

group	mean	Standard deviatin	Levene's test		t-test
			F value	meaningfulness	T value	degree	Meaningfulness
control	08/19	92/1	129/1	299/0	848/0-	24	000/0
exprimetal	64/24	76/2

According to table 2, data analysis in Independent T-Test and comparison of post-tests showed there is significantly more improvement between experimental groups compared to control groups.
Figure 1

4.  Discussion

The results indicated that compared to traditional approach, applying cognitive method had significantly improvement in teaching different concepts of the preposition.

5.  Conclusion

The present study was concerned with a cognitive approach to provide an instructional methods for Non-Persian speakers to learn prepositions “Be”. The results of the study will enrich our understanding of reconceptualization and learning by a cognitive approach. In this study, we taught the spatial as well as other senses of this prepositions. Data analysis in Independent T-Test (comparison of pre-tests in control and experimental groups) displayed there isn’t significantly improvement between prior knowledge of learners before teaching, whereas comparison of post-tests showed there is significantly more improvement between experimental groups compared to control groups. The results indicated that compared to traditional approach, applying cognitive method had significantly improvement in teaching different concepts of the preposition. The findings open up an effective perspective strategies in teaching prepositions for language teachers.

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Mechanical properties of living cells play an important role in helping to understand cell physiology and pathology. Evaluation of mechanical properties of cells may potentially lead to new mechanical diagnostic methods for some of these diseases. In this study, viscoelastic properties of the outer layer (cytoplasm and membrane) were extracted using standard linear solid model. Finite element modeling of the two cell layers is performed and the model is validated by experimental data. In the two-layer model, the effect of the radius of the nucleus and the location of the nucleus in the cell are investigated on the cell properties. By reducing the cytoplasmic radius ratio up to 43%, the whole cell properties follow the cytoplasmic properties and the effect of the nucleus can be neglected. The 50-second displacement change at a radial ratio of 0.53 increased to 4.5% compared to radial ratio of 1.58.  At a radial ratio of 0.43, a change in cell behavior was observed compared to the previous one, with a displacement change equals to 6.8% compared to radial ratio of 1.85 and a displacement reduction of 9.5% at a radial ratio of 0.53. The results demonstrate that the location of the nucleus and the ratio of the radius of the cytoplasm to the radius of the nucleus can effectively influence the viscoelastic properties and mechanical behavior of the cell.

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Objective: Hearing loss is the most frequent neurosensory defect in human. Mutations in GJB2 and GJB6 are responsible for 50% of autosomal recessive non-syndromic hearing loss (ARNSHL) cases. Here we report on the frequencies of GJB2 and GJB6 mutations and three large deletions spanning the GJB6 gene including Del (GJB6-D13S1830), Del (GJB6-D13S1854) and a >920 kb deletion in patients affected by ARNSHL referred to Kawsar's Human Genetics Research Center. Materials and Methods: In this study, 94 patients from 63 families with ARNSHL were investigated. Patient's homozygote for 35delG were screened and left out of the study and the remaining samples were analyzed by sequencing of GJB2 and GJB6 genes. Also the three large deletions spanning the GJB6 gene were analyzed by Real Time PCR Results: In this study we found GJB2 mutations in 13 families (20.6%) out of 63. The 35delG mutation was the most common mutation in the studied population (61.5%). Other GJB2 mutations were delE120, R127H, W24X, and V37I. The heterozygous or negative cases for the GJB2 mutations were screened for mutation in the GJB6 gene by sequencing and no mutation was observed. Also, we checked the three large deletions in GJB6, we found no mutations. Conclusion: Low frequency of mutations in the GJB2 gene implies that other genes may be involved in causing non-syndromic hearing loss in our country.

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Evaluating the response of the stem cells to different mechanical stimulation is an important issue to obtain control over cell behavior in the culture environment. One of the effective parameters in the mechanoregulation of stem cells is the microstructure of scaffolds. Evaluating the effect of microstructure of scaffold in the lab environment is very complicated. Therefore, in this study, the effect of scaffold architecture on mechanical factors in the scaffold was investigated under oscillatory fluid flow by using numerical modeling. In this study, distribution of shear stress and fluid velocity in three types of scaffolds with spherical, cubical and regular hexagonal pores with length of 300, 350, 400, 450 and 500 micrometers were investigated by using computational fluid dynamics method. The results of the computational fluid dynamics model showed that the scaffold with spherical and cubic pores shape with length of 500 micrometers and scaffold with hexagonal pores with length of 450 micrometers experienced shear stress in the range of 0.1-10 mPa. This range of the shear stress is suitable for differentiation of the stem cell to bone cells. Moreover, the result of exerting oscillatory fluid flow to these scaffolds indicated that dead zones of the scaffold, where isn’t suitable for cell seeding, was decreased due to the access of fluid flow to the different area of scaffold. The results of this study can be used in a laboratory to achieve optimal stem cell culture to provide suitable environment culture for differentiation of stem cells toward the bone cell.
 

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Transmission network expansion planning is a challenging problem with the aim to determine the type, location, and time of the equipment to be added to the existing transmission network in order to desirably meet the increasing load demand. On the other hand, reactive power sources are the other important components of the power system, which are used improve voltage profile and maintain the system stability. This paper, presents a comprehensive AC load flow based framework for concurrent expansion planning of transmission networks and reactive power resources. Although major advances have been made in optimization techniques, finding an optimal solution to a problem of this nature is still challenging. Using some linearization techniques, a mixed-integer linear programming (MILP) model for transmission expansion and reactive power planning is proposed. In order to show the influence of the concurrent transmission network expansion and reactive power resources planning in reducing investment costs, simulation studies and analysis of the numerical results are carried out on the Garver 6-Bus and the standard IEEE 24-bus test system.
 

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Experimental evaluation of overall convection heat transfer coefficient of a rectangular bar in the vicinity of a flat plate is investigated. A quad of rectangular shape and later a quad with the cause of optimal heat transfer are placed at the near and the inside of a turbulent boundary layer over a flat plate. The overall convection heat transfer coefficient of the flat plate are measured and compared to the case similar to a single flat plate. A low speed wind tunnel is employed to maintain main flow field at the requested speed and special electrical circuit is prepared to provide heat and measure heat losses from the flat plate. Conclusion is made that when the obstacle closes to the flat plate, the total convective heat transfer coefficient increases to a maximum and then reduces again by moving towards the plate. Distance from the flat in which the maximum heat transfer coefficient occurs is reported.

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In this paper motion of some blood clots with different mechanical properties in the cerebrovascular arteries is investigated. Blood clots mostly are originated from heart or other cardiovascular arteries and by entering the cerebrovascular arteries trigger occlusion and deprive the brain’s tissue from proper perfusion. To study this phenomenon, we used a patient-specific geometry of cerebrovascular arteries and due to obtain the motion of clot and blood’s flow in cerebral arteries, algorithm of fluid-structure interactions was used. Although previous researches have not considered the effect of mechanical properties on the motion of clot, our results demonstrate the variation of the dynamic parameters of the clot’s motion by changing the mechanical properties. We show that by increasing the rigidity of the clot, their tendency for entering to the larger arteries is raised. Also other dynamic parameters like clot’s average velocity altered when the mechanical property of the clots changes. Mechanical parameters have the main role in the motion of clots and by investigating them, our sight to the mechanism of pathologies would expand, moreover, strategies of the cerebrovascular treatments would be fascinated in the future.

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SCID is a lethal genetic autosomal recessive disorder that has been observed in humans, dogs, mice, and horses. Affected animals are incapable of generating specific antigens for immune responses needed to protect them from infectious diseases. The frequency of affected recessive allele varies in different regions so that the outcome of normal breeding with carriers of recessive alleles is differently distributed. Little information is available for SCID carriers in Iranian horses to prevent carriers breeding. In this study, the occurrence of the SCID alleles was tested in representative samples of Persian Arabian (or Asil) horses. Blood samples were collected from 244 Arabian horses in eight provinces of Iran. The ARMS-PCRs were used for the first time to identify SCID carriers, based on three distinguishing primer pairs. Each sample was used in two separate PCRs with a common forward primer. The two reverse primers differed in their 3′ end: one reverse primer could pick the wild-type allele while the other could pick the mutant allele with a 3′ end deletion. An internal control (HMS02 locus) was used in both reactions to verify whether the amplifications worked correctly. The results showed a mutated allele frequency of 0.8% in the Arabian horse population of Iran. This is the first report identifying SCID carriers’ frequency among Arabian horse population in Iran.

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Stress urinary incontinence (SUI) is characterized by the involuntary transurethral leakage of urine caused by an increase in abdominal pressure in the lack of an adequate bladder‎ ‎contraction that raises the vesical pressure to a level that exceeds urethral pressure‎. ‎Adult women are most commonly affected by SUI which is believed to be caused in part by‎ ‎injuries to the pelvic floor sustained during childbirth‎. ‎Despite the large number of women affected by SUI‎, ‎little is known about the mechanisms associated with the maintenance of urinary continence in women‎. ‎The work in this ‎research ‎focuses on studying the behavior of the bladder and the dynamics of the urine during an increase in abdominal pressure like a cough‎. ‎The computational model is developed by using the Finite Elements Method (FEM) and Fluid-structure interaction (FSI) techniques. ‎The results show a good accordance between the clinical data and predicted values of the computational models. ‎Simulated pressure is more accurate in the model in which non-linear material properties are utilized. The results of the computational methods indicate that by using numerical techniques and simplification of the physics of biological systems, clinical results can be reached in virtual environments in order to understand pathological mechanisms.

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Stem cells due to their ability of self-renewing and the potential of differentiating to different cell lineages are the ideal choices in regenerative tissue engineering. Under cyclic loading, these cells could differentiate to those kind of cells that experience similar conditions inside the body, like osteocytes and chondrocytes. In this research, the purpose is to investigate the effect of the 10 percent cyclic strain with the frequency of 1 Hertz on the mechanical response of a single mesenchymal stem cell cultured in a fibrin hydrogel block, using the finite element method and considering the role of integrins and implementing the Simo’s hyper-viscoelastic model for the cytoskeleton as long as the uniaxial loading leads the cell to differentiate toward Fibrochondrocyte. The results of presented model show that the averages of the circumferential, radial and shear stresses are 240, 260 and 140 Pascal, respectively and corresponding forces are 24, 45 and 15 Pico-Newton. The results imply that stresses and forces generated inside the cytoskeleton are large enough to elicit a different response from the cell. This research results can be very effective for better designing of biological experiments.

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In the present study direct contact heat transfer between hot water and cold air in vertical pipes with cocurrent downward flow is investigated. Experiments are performed in turbulent condition using 1, 1.5, 2 meter pipes lengths with 0.021 meter diameter. The hot water temperature was varied between 35 to 50 degrees of Celsius and the air temperature was varied between 25 to 35˚C. Air velocities were chosen to be 3, 5, 7, 9 and 11 m/s and the rates of flow rate of water was selected as 5, 8 and 10 lit/min. Two phase annular flow pattern of water and air is formed in the vertical pipe. The interface area between water and air was measured by Image Processing taken from shining laser light sheet on the transparent tubes. Over 80 percent of heat was transferred by evaporation and less than 20 percent was transferred by convection. In all three pipes, Nusselt number decreased with increase in flowrate of liquid phase. In all the verified temperatures, Nusselt number was decreasing by increasing pipe length. Experimental values for Nusselt numbers were compered to empirical values for smooth surfaces. Finally, some adjustments were suggested for Nusselt number correlation by fitting experimental data into existing correlations for pipes with smooth surface. Proposed correlations for heat transfer resulted in Nusselt number with ±15.26% average error.

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In this paper, control position of a pneumatic actuator with the PWM solenoid on/off valves using two different pneumatic circuits performed. After deriving the governing dynamic equations, to investigate the circuit effect on system performance, mentioned two pneumatic circuits are introduced. Then in order to control the position of the pneumatic actuator, for both circuits, sliding mode and proportional-integral-derivative controllers are designed. In proceeding, optimum controller parameters are determined by genetic algorithm to achieve minimum control energy and position error. Finally, by performing simulations in Matlab Simulink, performance of designed controllers with optimal parameters is evaluated and compared in the presence of disturbance. According to the obtained results, by comparing the performance of two circuits, it is observed that the first pneumatic circuit with two solenoid valves can track the high-frequency sine reference input better and more precisely in the presence of a nonlinear sliding mode controller. The position tracking error in low-frequency sine reference input using a classic proportional-integral-derivative controller, for a single-valve pneumatic circuit is considerably less than that of a pneumatic circuit of two valves. This indicates the input-output quasi linear behavior of the pneumatic actuator in a single-valve circuit.

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As the use of mechanized tunnel boring machines (TBMs) increases, the performance of these machines has become increasingly important for researchers to work on. Disc cutters, as one of the main components of the cutter head, are responsible for transmitting the thrust force to the rock and breaking it. Studying the rock-cutting process by TBM disc cutters is vital to mechanized tunnel excavation. For this reason, this issue has been widely studied by researchers in recent decades. The shape and layout design of the cutter head, disc cutters spacing, and the size and shape of cutters are the adjustable factors in improving the efficiency of rock cutting and TBM excavation. It is important to determine the forces acting on the disc cutters in mechanized tunnel boring machines because these forces are used in the design. A review of the history of studies shows that lateral forces have been studied much less than other forces. Therefore, in this article, a numerical study of the side forces on the disc cutters and their relationship with the installation radius and the tip width has been studied. Furthermore, the information of lot 2 Kani Sib water conveyance tunnel has been used to validate the results. For this, numerical simulations have been conducted with three types of 17-inch disc cutters in installation radii of 0.3 m, 1 m, and 2 m with tip widths of 18.5 mm, 19.6 mm, and 20.8 mm. The results of the numerical models show that the side forces acting on the central disc cutters with low installation radius are much higher than others. Additionally, these forces are mainly asymmetrical and become symmetrical as the installation radius increases. Central disc cutters are subjected to unbalanced and asymmetric forces because of the excessive side force. This will cause the disc cutter bearing system to malfunction and increase costs significantly. A decrease in the balance of the cutter head and increased vibrations are other consequences. Increasing the tip width aggravates this condition. The damage pattern of the disc cutters in lot 2 Kani Sib tunnel confirms this conclusion. According to this project, more than 74% of central cutters' failures with low installation radius are related to bearing problems. This type of failure is caused by large asymmetric side forces, while only 26% of the face disc cutters with a large installation radius failed in this way, which confirms the results of the numerical models.