Showing 58 results for Farzi
Volume 0, Issue 0 (in press 2024)
Abstract
In order to facilitate the release of floods from the dams and to prevent their damage or collapse, a structure called a spillway is used. Due to the natural and variable flow of the input to the reservoirs of the dams, there are times when the river inflow exceeds the consumption amount in the downstream agricultural lands. In these cases, excess water is discharged over the crest of the weir and flows towards the spillway, which causes high velocities. This high velocity creates low pressure areas on the spillway concrete surface, which can cause major damage to the spillway or even endanger the integrity of the dam structure. Therefore, the dam spillway must safely dissipate the kinetic energy. One of the types of weirs is the stepped spillway to facilitate the passage of the flow over the dams. One of the most obvious practical features of stepped spillways compared to other spillways is the considerable energy dissipation along the spillway. Care should be taken in designing and selecting the type of spillway to prevent potential erosion and reduce kinetic energy as the water flow passes over the spillway. One possible solution is to use a stepped spillway instead of a smooth spillway. In this study, a numeral model of a stepped spillway with different steps and slopes is used. For this purpose, ANSYS software is used for modeling free surface with application of k-ε turbulence model. In the present study, numerical simulation using the Volume of Fluid (VOF) model was used to investigate the mixing phenomenon of two phases of air and water of the free surface flow. The flow field was continued until the residuals reached 10-7. Compared to simpler models such as Mixture, which operates solely on the basis of averaging the properties of two phases, the VOF model, is separating the phases and considering the effects of the interface. The VOF model, is capable of more accurate simulation of phenomena such as fluid mixing, turbulent flows, and heat transfer in multiphase flows. A number of hydraulic specifications which are considered in designing the stepped spillways are the pressure on the surface of the steps, velocity distribution and energy dissipation. The results from the numerical models were compared with experimental studies. They showed acceptable agreement with physical simulations. Results show that discharge and spillway slope increment reduces the amount of energy loss. In the spillway with 5 steps, for a discharge of 0.063 m3/s, the amount of energy dissipation at a slope of 26.6 degrees changes from 85 to 82% at a slope of 45 degrees, which shows a decrease of 3%. With the increase in discharge, the flow depth increases and reduces the effect of the roughness of the steps on the upper layers of the flow. Increasing the height of the steps increases the rate of energy dissipation and also increases the occurrence of negative pressures in stepped spillway. In this case, the contact surface between the main flow and the eddy currents increases. With the increase in the height of the steps, the dimensions of the rotating vortices also increase and cause a larger radius of rotation on the steps. The presence of these large rotating vortices separates the flow from the bottom of the steps and reduces the pressure on the surfaces. The number and dimensions of steps can alter the energy dissipation rate. Increase in the number of steps in a spillway with constant height, reduces the energy loss as the result of steps dimensions being shrunk
Volume 0, Issue 0 (in press 2024)
Abstract
Foothills, plains, alluvial areas, and sloping areas whose soil is geologically susceptible to landslides, can become unstable and dangerous. In Iran, because of their soil type, Mazandaran, Gilan, Lorestan, Golestan and Khuzestan provinces are more vulnerable to landslides than other provinces. But taking into account factors such as earthquakes, extreme weather, and human interference, other parts of the country can also be prone to landslides. In case of rainfall and absorption of water by clay layers, the possibility of landslides increases. If the slope of the land is suitable, the slope will move on the clay layer and the thrust will occur downwards. In many mountains and steep areas, the conditions for slope failure may be available in terms of the slope angle, the type of soil and the presence of clay layers. But in the absence of sufficient soil moisture, this phenomenon is not observed. Landslides occur whenever rainfall happens and water penetrates the clay layer. Cutting down forest trees, destroying vegetation and pastures, along with possible rainfall and soil moisture, cam cause landslides on steep slopes. In fact, land use changes contribute to landslides. By examining the statistics over the last three decades in the northern provinces of Iran, it can be seen that landslides were far less likely when there was proper vegetation. The occurrence of heavy rains can cause failure in a large number of soil slopes. During these heavy rainfalls, the underground water level rises and increases the pore water pressure and reduces the stability of the soil. The purpose of this study is to investigate changes in pore water pressure and the factor of safety for slope stability. The flow of water inside the soil is numerically modeled as a two-dimensional, saturated-unsaturated, unsteady flow. The finite element method (FEM) is used to calculate the pore water pressure and the limit equilibrium method is used to determine the factor of safety for slope stability. To simulate the unsteady flow, time duration of 4 days is used with a time step of 0.1 days. The rainfall duration was assumed to be 24 hours. The intensities of different rainfalls are used as the input flux on the soil surface. The soil moisture curve, which shows the relationship between suction-moisture content and suction-hydraulic conductivity, is used. The results show that different rainfall intensities have different effects on soil moisture profile. As the intensity of precipitation increase, the factor of safety of slope stability decreases. This decrease is steeper for the first 24 hours of rainfall and over the three days after the rain stopped, its slope decreased. For example, for a rainfall intensity of 2.04 mm/hour and the duration of one day, resulted in a factor of safety of slope stability equal to 1.853, and at the end of the fourth day, it was 1.743. In other words, the factor of safety decreased by 5.9%.
Volume 1, Issue 3 (Autumn 2020)
Abstract
Investigating the role of narcissism in the tendency to doping in bodybuilding athletes
Volume 1, Issue 4 (Winter 2021)
Abstract
Examining the dimensions of mental strength in the performance of athletes
Volume 2, Issue 2 (Summer 2018)
Abstract
Methyl Tert-butyl Ether(MTBE) has been used as a booster in gasoline octane numbers in many countries, but after a short time due to the high absorption in water and the possibility of entry into groundwater, its use in developed countries is prohibited. In this work, for the first time, to reduce the adverse environmental effects, MTBE was encapsulated, and release control was considered. For this purpose, the inverse mini-emulsion polymerization of monomer methylmethacrylate(MMA) was performed in the presence of MTBE and in the cyclohexane medium by oil/water/oil. Poly methyl methacrylate/MTBE nanocapsules were synthesized in 0.5, 1, 2 ratios of MTBE to methyl methacrylate (R = MTBE / MMA).
The effect of changing R values on conversion polymerization, on encapsulation efficiency of MTBE and on the morphology of capsules was investigated. For this purpose, TGA and TEM were used. Changing the R ratio from 0.5 to 2 allowed the capsule to be controlled in the range of 50-500 nm. The start of the MTBE degradation range of 130 ° C increased to 250 ° C due to the presence of the MTBE inside the capsule, and it was possible to start controlling the release of the nucleus by heating and starting at a temperature of 250 ° C. By addition of 1.5% of the capsules to the gasoline, the octane number increased by 5 units.
According to the results inverse mini-emulsion polymerization is a suitable method for encapsulating and reducing the environmental effects of MTBE by limiting its contact with the environment.
Volume 4, Issue 3 (2014 2014)
Abstract
Volume 5, Issue 12 (3-2017)
Abstract
Archetypal criticism is one of the contemporary literary criticism main approaches which discovers the nature and characteristics of the myths and archetypes and their role in literature. This article tries to carry out archetypal criticism of “The story of Amir Arsalan” according to the Jung’s individuation theory. As the hero searching progress and perfection and finding his archetype, Amir Arsalan begins journey and awakes by seeing the image of Farrokhlega (his anima) and achieves new levels of awareness. By passing of the persona archetype he can eliminate the shadow and get married and unify with anima (Farrokhlega) by the help of the wise old man and ends his individuation process and finally, he achieves his archetype. However, he experiences death and rebirth archetypes as revival of life and inner revolution by entering to cave and well- indicating return to fetus period(ritual death)-leaving there as the secret of rebirth.
Volume 6, Issue 3 (No.3- 2014)
Abstract
Sassanid reign, as one of the most powerful Iranian dynasties, lasted for over four centuries before the Arab Moslems’ attack to Iran. The great Sassanid government managed to convert the Feudal Iran of Parthian era into a united and strong country thanks to its central government and Zoroastrianism nationalism; this not only recreated political power but also hugely revolutionized the cultural and social issues in Iran. However, different factors, after a while, led to the gradual weakness and suppression of this dynasty before the Arab Moslems’ attack. In this research, auditing the historians of all these four centuries of the early Islamic era including Abou- HanifehDinvari, Yaghoubi, Masoudi, Tabari, and EbneMoskouyeh exactly and from all aspects, many attempts have been made to figure out and analyze the reasons of this gradual weakness and overthrown of Sassanid Reign the emnloying a historical-descriptive method. The results of this research reveal that in the view of the historians of all these four centuries of the early Islamic era, the following factors were the most crucial reasons of Sassanid’s downfall and defeat before the Arab Moslems: religious prejudice, high position of Zoroastrian clergymen, well-borns’ increasing power, massacre of the royal family by Shirouyeh, the last Sassanid kings’ lack of authority, a military coup against the kings, long exhausting overseas battles, especially the constant wars against the Rome Empires, toppling the Ale-Lakhm by KhosrouParviz, economic pressures on people and heavy taxes, natural disasters like the Tigris and Euphrates rivers bursting their banks, and hidden helps.
Volume 6, Issue 3 (11-2016)
Abstract
Horizontal development of the cities has resulted in much destruction environmentally and economically. Two of the major consequences of such destruction is imbalanced development and inappropriate application of lands in the cities that are referred brownfield in this article. Brownfield in the urban planning jargon, a brownfield site (or simply a brownfield), is a type of land formerly used for industrial purposes or some commercial applications. The brownfield concept was first introduced by the British government and was used in accordance with the sustainable development policies which is mostly focused on the environmentally polluted lands. In the last two decades, redevelopment policies of brownfield as a crucial practical solution for preventing disperse growth of cities and also supporting the concentrated growth of cities have been attracted more attention. The main features of the brownfields are: -1 Pollution: each land in which an environmental complication has the occurrence probability. -2 Empty and leaved without using and in general lands and properties that their activities have been closed or not been used anymore. Of course, some of the terms that must be separated from the brownfield areas are: greenfields and grayfields.
Greenfields are those lands that previously has not been developed and often are rural or suburban. These green sites are located in the edge of small or large cities and have better accessibility and more palatability with additional space for future development.
The term grayfield, was defined in 1998 by new urbanism congress. Unlike the famous terms of greenfields (the rural undeveloped) and brownfields (polluted urban sites), the gray lands are called to the large undeveloped sites that have good reasons for redevelopment. The term of grayfield can be used to describe any kind of redevelopment that significantly is not polluted. But regarding the importance of environmental protection and sustainable development and realization their policies, it is essential to eliminate or reduce the environmental pollutions purposefully to achieve the redevelopment of brownfields.
For the sake of importance and novelty of the subject, redevelopment of Brownfield with the objective of efficient applications of lands in cities and reducing the environmental pollution and also improving the social-economical context of these fields is the subject of this article. Brownfield of Kan stream in Tehran was selected as the case study. The field was selected as it is one of the few major barren Brownfield in Tehran. They are not only in the leaved brownfields but also regarding the river-valley nature, the fields has specific ecological and tourism features. Unfortunately, due to lack of planning and management, these brownfields have been converted to the locations of rubbish depot and uncontrolled polluted waters and therefore infected with the environmental pollution. The methodology of this article is descriptiveanalytical using library studies. After studying the theoretical framework, defining features of brownfield, literature review, objectives and the importance and of these fields, the redevelopment process of Kan stream Brownfield are presented. Finally, the conclusion and analysis of the actions are conducted in redevelopment of brownfield with social, economical and tourism approach.
After comprehensive studies, in order to determine the kind of landuses in Kan brownfields, establishing a national and even an international performance scale park is designated as the planning vision. In this context, the objectives of the redevelopment planning process Kan brownfield included:
creating a touristic space to enhance the region›s tourism identity, planning with emphasis on providing recreational services for all social classes, such as children, elderly people and women and people with disabilities (all divisions with regard to sex, age and physical aspects), strengthening of the relationship between people and nature and to replacing normal social activities and improvement environmental conditions; Developing ecotourism in urban environment regarding and it s benefits beyond natural landscapes, enhancing green space for per capita in Tehran city and attainment to the standard limits for
environment qualities by using marginal lands and rivers sanctums.steel plates. In addition these bars are pre- tensioned by means of cable passing through them in order to behave properly to the applied forces.
The way that the bars are moved through the retraction process and the function of the building effects on the selection of the covering materials. In this structure, as the distance between the bars is changed during the deployment process it is required to use a flexible but strong material that can resist repeated retraction. Therefore, a flexible membrane that is strong enough during movement and has a proper foldability such as ETFE is one of the best alternatives for covering the roof. ETFE is also able to penetrate enough light inside of the building when the roof is in fully closed position and this in turn reduce the energy required for running the building.
The membrane is also attached to the bars though the slots that have already been created during fabrication and is fasted by means of pinned curve plate. This is also worth to mention that in this structure, the placement of the moveable components underneath the covering material support the whole structure even in severe weather conditions. Therefore, this increase the life cycle of the system and decrease the maintenance cost.
In summary, this paper proposes a new solution for a retractable curved roof system that can not only be transformed from an open to closed configuration but is also able to support itself structurally even during movement and transformation. In other word, the structural and transformable components are integrated and are able to make the whole structure stable during transformation.
Volume 7, Issue 2 (7-2018)
Abstract
The water fern weevil, Stenopelmus rufinasus Gyllenhal (Coleoptera: Curculionidae), is considered as the most important biological control agent of Azolla spp. in the world. Azolla spp. was introduced in Iran in 1986. In August 2017, two specimens of S. rufinasus were collected on Azolla spp. in waterways near Anzali lagoon and Rice Research Institute of Iran (RRII) in Guilan province for the first time. Identification was based on molecular sequencing. This is the first record of S. rufinasus from Iran.
Volume 7, Issue 3 (Summer 2021)
Abstract
Backgrounds: This study aimed to analyse hybrid Entroaggregative/Uropathogenic Escherichia coli (EAEC/UPEC) isolates. To do so, the antibiotic resistance pattern and virulence genes were investigated in E. coli strains isolated from clinical specimens of patients hospitalized in Isfahan, Iran.
Materials & Methods: Disc diffusion method was used to determine the antibiotic susceptibility pattern of EAEC/UPEC isolates. Also, virulence determinants of these isolates were determinated by singleplex and multiplex PCR.
Findings: Overall, a total of 148 E. coli isolates were collected, of which 12 (8.1%) isolates were hybrid EAEC/UPEC strains, then antibiotic susceptibility examination was operated on these strains. The higest antibiotic resistance rate was related to ofloxacin (42%), followed by trimethoprim-sulfamethoxazole (41%), ceftriaxone and cefepime (33%), and cefoxitin (17%). All the isolates showed susceptibility to fosfomycin.
Conclusion: According to the current study, since resistance to fluoroquinolones has increased in hybrid strains, monitoring the drug susceptibility of hybrid strains seems critical in Iran. Fosfomycin is considered to be the drug of choise for infections caused by multidrug-resistant (MDR) Gram-positive and Gram-negative bacteria. Fortunately, 100% of the strains were sensitive to fosfomycin.
Volume 7, Issue 25 (5-2019)
Abstract
The metaphorical and symbolic structure of the myth and its ancient foundations always provide the basis for the return of mythology in peoples' minds and languages. Ritual beliefs and ceremonies in different regions reveal the powerful presence of human thoughts and aspirations. The symbolic presence of mythical plants and animals in contemporary era is one of the characteristics of the mysterious nature of the past and of life, which refers to the hierarchy of life, that is to say, the passage of time from immortality to the universe of incarnation. Stone engraving is one of the neglected dimensions to trace this stage. The engravings of animals or plants on the tombs of different tribes may be proof of the presence of these mysterious phenomena of the human mind. They are mysterious attitude to life and death and always suggests the survival of mythological views and beliefs. In this research, the authors have tried to explain and study the cemeteries of the village of Souran using the method of mythical criticism and field observation. The results of the research showed that most mythic beliefs persist in the form of the symbolic presence of animals and plants along the signs of the foundation of myth, which testify to the resurrection and survival of early doctrines in general beliefs of the region; By moving through history and reaching the present age, it continues to affect the image and belief of people in the region.
Volume 8, Issue 2 (7-2008)
Abstract
Hotels are fundamental elements of tourism industry and provide various services for tourists. Moreover, hotels development has an important impact on tourism industry development. Therefore, an understanding of hotels relative efficiency performance, over a period of time, is important for practitioners, analysts, and policymakers alike.
The main objective of this paper is to measure the efficiency of the four and five stars hotels in Tehran. A Data Envelopment Analysis (DEA) is employed to investigate the technical efficiency of eight hotels using the data over the period 1380 - 1384. DEA analysis is a methodology for analyzing the relative efficiency of units having the same multiple inputs and multiple outputs. In this study, the input variables comprise employee, rooms, restaurants and land and the output variables include hotel income and occupancy rate.
The results show that technical and scale efficiency scores in all periods are relatively higher but there is no a regular trend over the period under study. Since 1380 to 1384; 75, 62.5, 75, 62.5, and 50 percent of the selected hotels were respectively efficient under the constant and variable to scale assumptions. Moreover, the findings confirm that more scale efficiency (0.997) refers to 1380 and less scale efficiency (0.894) refers to 1381 and 1382. The results also show that more technical efficiency, on average, under variable to scale assumption (0.964) refers to 1380 and less technical efficiency (0.894) refers to 1384. Finally, the efficiency of the five stars hotels is more than the four stars hotels implying the priority of the five stars hotel’s development in Tehran.
Overall, the findings indicate that the particular problem is mismanagement in the Tehran’s hotels. Consequently, it caused the average scale efficiency to be more than the average technical efficiency. Since management plays a vital role in the efficiency improvement of hotels, this paper suggests the improvements of managerial systems in the hotels. More specifically, education, employment and Customer Reservation Systems (CRS) are the main factors influencing the efficiency.
Volume 9, Issue 1 (12-2009)
Abstract
In this study, pulsating hydroforming of tube in a box die is simulated using the three dimensional finite element method to investigate the mechanism of improvement of the corner filling. In addition, the results obtained from the simulation are compared with experimental observations, and the validity of the simulation results is verified. Based on a better understanding of the mechanism of improvement of the corner filling, a new pulsating pressure path is proposed to increase the corner filling. It has been shown that the proposed pulsating pressure path is more effective in increasing the corner filling of the box shape tube hydroforming process.
Volume 9, Issue 2 (Spring 2024)
Abstract
Aims: The primary objective of this study is to examine the relationship between alexithymia and Post-Traumatic Stress Disorder (PTSD) among patients experiencing varying degrees of Chronic Pain (CP).
Method and Materials: This study utilized a descriptive causal-comparative approach. The participants were drawn from patients referred to pain and physiotherapy clinics in Tehran from 2022 to 2023. Out of 300 CP patients, 150 patients with high CP levels and an equal number with low CP levels were purposively chosen. The participants completed the Graded Chronic Pain Scale (GCPS), Perth Alexithymia Questionnaire (PAQ), and Posttraumatic Stress Disorder Checklist (PCL). Data analysis was performed using SPSS-24 software, employing multivariate analysis of variance.
Findings: The findings revealed a significant difference in the levels of alexithymia and PTSD between the two groups (P<0.001). Patients with high levels of CP demonstrated increased negative difficulty identifying feelings (F=241.87), positive difficulty identifying feelings (F=389.01), negative difficulty describing feelings (F=190.61), positive-difficulty describing feelings (F=347.81), general-externally orientated thinking (F=376.28), reexperiencing (F=246.75), avoidance (F=100.74), negative alterations (F=378.01), hyperarousal (F=388.46), and emotional numbness (F=388.47) compared to their counterparts (P<0.001).
Conclusion: These findings underscore the intricate relationship between CP, alexithymia, and PTSD. Therefore, the need for comprehensive assessment and management strategies addressing the interplay of these factors in patient care is highlighted.
Volume 10, Issue 2 (7-2010)
Abstract
The aim of this paper is twofold. It first investigates the demand for international reserves using panel data for 32 developing countries during the period 1975 – 2004. To this end, an Error Correction Model (ECM) approach is employed to estimate the empirical model and then a capital asset pricing model (CAMP) is used to determine the composition of the foreign exchange reserves. A dummy variable is included in the model to consider the effect of changing exchange rate system on the demand and the composition of international reserves.
The results show that there is a negative relationship between exchange rate flexibility and the demand for international reserves.
Volume 11, Issue 2 (9-2011)
Abstract
Aluminum alloys are desirable in industry due to their excellent high-strength to weight ratio, corrosion resistance, and weldability. However, at room temperature, the formability and the surface quality of the final product of these alloys are low. So in recent decade, new process, hot metal gas forming, has been introduced. This paper investigated new method of hot aluminum alloys forming using gas. Experimental test for bulge forming was designed and made. In addition to experimental test, finite element analysis of process was done. Results showed that hot metal gas forming provides highest forming temperature for aluminum alloy blank and with increasing blank temperature up to optimum temperature of hot forming, there is reduced pressure forming and significant improvement of formability. Results of experimental test and finite element analysis including determination of optimum temperature for forming of special aluminum alloy, maximum formability in this process, required forming pressure, minimum thickness, thickness and temperature distribution were conformed.
Volume 11, Issue 4 (12-2022)
Abstract
In this study, the effects of powder and leaf extract of Moringa oleifera on hemolymph factors of Litopenaeus vannamei in response to salinity stress were evaluated. After 8 weeks of feeding with powder (25, 50 and 100g / kg) and extract (0.25, 0.5 and 0.1 g/kg) leaves of Moringa and control treatment without Moringa, all treatments were exposed to short-term salinity stress (5 and 55 ppt). There was a statistically significant difference in total and differential count of homocytes in different dietary treatments in all three normal conditions and under salinity stress of 5 and 55 pp (p<0.05). Under normal conditions and high salinity, shrimps fed with Moringa leaf extract showed higher number of homocytes than other treatments. In stress-free conditions, the number of semi-granular cells in powder and extract treatments was higher than the control group. At 5 ppt, Moringa powder treatments had higher semi-granular and at 55 ppt salinity, the leaf powder group (100 g/kg) and the leaf extract (0.25 g/kg) showed the highest values, respectively. Overall, the results of this study showed the positive effects of using Moringa leaf powder and extract on innate immune system function and exposure to salinity stress in shrimp
Volume 11, Issue 49 (April and May 2023)
Abstract
The transfiguration of a person into a corpse is one of the mythological and symbolic elements in Kurdish folktales. In transfiguration, the shape and nature of creatures are changed from one state to another by using supernatural power of person or creature. The current study was carried out in a descriptive-analytical method based on the library sources and field research. In this research, using mythic criticism, the roots of petrification were investigated. Then, the way people faced it, as well as the causes and tools necessary to get rid of this change, were discussed. The results showed that the reflection of mythical beliefs, passing through history and reaching the present age, in Kurdish folktales, shows the immortality and dynamism of these beliefs, by deciphering and analyzing of which, the common root of this mythological view can be discovered and interpreted.
Volume 12, Issue 1 (12-2020)
Abstract
Abstract
Urinary tract infection is one of the most common and common bacterial infections, accounting for a significant proportion of hospital admissions (about 30-40%). Silver nanoparticles work by releasing silver ions against various bacteria. The fact that bacteria are not resistant to nanoparticles is very important and therefore will affect a wide range of bacteria.
Materials and Methods
In this study, 50 specimens of positive cultures with urinary tract infection referred to Imam Reza Hospital Laboratory in Bojnourd were studied. Resistance and susceptibility of the isolates were determined by disk diffusion method. In this study, antibacterial effects of silver nanoparticles were investigated by microdilution method using aqueous extract of Ganoderma leucidum. Vegetative electron microscopy was used to measure the size and shape of silver nanoparticles. In addition, infrared spectroscopy analysis was performed to investigate possible organic compounds involved in the synthesis of nanoparticles.
Results: The highest antibiotic resistance was related to ampicillin (84%). The resulting nanoparticles were 20 to 45 nm in size.
Conclusion:
The produced nanoparticles have antimicrobial activity and can be a good alternative in the treatment of antibiotic resistant infectious diseases.