Search published articles
Showing 42 results for Ghodsi
Volume 2, Issue 8 (Winter 2022)
Abstract
This study aimed to identify and investigate the factors affecting women's participation in mountaineering activities on Binalood Mountain. The method of the present study was descriptive and surveyed kind. The statistical population of this study included 150 women who were members of mountaineering groups in Neishabour. The research measurement tool is a researcher-made questionnaire whose face and 12 sports management experts confirmed content validity. Cronbach's alpha coefficient of the questionnaire was calculated to be 0.84. In this questionnaire, factors affecting women's greater participation in mountaineering activities were categorized in the form of three indicators: personal-family, social-cultural and managerial factors. Based on the findings, among the investigated indicators in the participation of women in mountaineering activities, the most important personal and family factors, then socio-cultural and managerial factors, have been obtained, as well as among the factors affecting women's participation in mountaineering activities. There is a significant difference between the mountains of Binaloud based on age and education, but there was no significant difference based on marital status and employment.Volume 6, Issue 22 (10-2018)
Abstract
Human needs Formalizes each new type of language. In eighty decade expanded Argot in human every speaking that targeted religions, polity & gender taboos and mixed with modern problems. Resulting of cause of cultural studded may be analysis by Cultural Studies .For lexicography field impractical linguistics noticed only inner entry of same lexicon and fields of historic, sociology, politic arn’t notable but cultural studies with interdisciplinary way and equal vision to formal language & common opens the atmosphere to show the informal language in formal institutional. This essay attempts with content analysis survey literal & topic eighty decade in five sours of books & lexicons that have sow Argot. For finds cause of Argot are expanding free time entering IT & technology be hidden in virtual spade & expand of Soap Opera in Eight Decade. Without misconstruing survey enters of Argot words without taboo to national language can boost formal language.
Volume 8, Issue 3 (Autumn 2018)
Abstract
The existence of a crisis such as a climate change and greenhouse gas emissions, due to the excessive consumption of energy and the share of buildings in it, is one of the global problems that is undeniable. On the other hand, the influence of geometric indicators on thermal behavior has been experienced over decades in the nature of animals and plants. Historically, Architects have always tried to create appropriate solutions with the intention of providing a comfort zone for human in line with the climate. Choosing the form and scales are from the solutions adopted.
This study tries to study the contribution of each of the effective geometric indicators by using a software simulation method as well as being a step to provide the principles for choosing the volumes by architects and designers. With this purpose and with studying the previous researches, the most important indicators and used methods were identified and selected. 10 volumes including 5 simple volumes and 5 volumes of the compound that are more abundant among other residential forms, especially in hot and arid climate, were selected in four floors with residential use. The contribution of each geometric indicator has been investigated by simulating the thermal behavior of each volume in Autodesk Ecotect Analysis software and Design-Builder software.
The simulation results indicate that after the form of the building, the relative compaction indicator, and then the proportion of the surface of the south facade are more important. In addition to geographic indicators, east-west orientation provides the optimal response to the total annual energy consumption of the building.
This study tries to study the contribution of each of the effective geometric indicators by using a software simulation method as well as being a step to provide the principles for choosing the volumes by architects and designers. With this purpose and with studying the previous researches, the most important indicators and used methods were identified and selected. 10 volumes including 5 simple volumes and 5 volumes of the compound that are more abundant among other residential forms, especially in hot and arid climate, were selected in four floors with residential use. The contribution of each geometric indicator has been investigated by simulating the thermal behavior of each volume in Autodesk Ecotect Analysis software and Design-Builder software.
The simulation results indicate that after the form of the building, the relative compaction indicator, and then the proportion of the surface of the south facade are more important. In addition to geographic indicators, east-west orientation provides the optimal response to the total annual energy consumption of the building.
Volume 10, Issue 2 (6-2010)
Abstract
Abstract The problem of scour and variations of bed topography, which is influenced by different parameters is very important in river engineering. In order to study the influence of discharge, relative flow depth and relative channel radius on dimensions of scour hole, experiments were conducted. The results are given in this paper.
Volume 11, Issue 1 (4-2011)
Abstract
Abstract: The measurement of bed profile in a mobile bed is very important for hydraulic engineers. The traditional instrument for this purpose is point gage. Working with a point gage is a difficult task, especially when bed topography of large size scales has to be recorded. In this paper, a new instrument for measuring the bed profile in a mobile bed called "Laser Bed Profiler" is introduced. The developed instrument uses the laser beam and without touching the bed records the data. The laser bed profiler instrument has been designed with the purpose of analyzing the scoring pattern in laboratory channels. This instrument is capable of measuring the changes of the bed profile in straight and bend channels. Moreover, the instrument is capable of recording the bed profile around various hydraulic structures (such as bridge piers, abutment, spur dike and lateral intake). Amongst the main advantages of the developed instrument are: 1) recording the data without touching the bed surface and 2) its high speed and precision. This paper gives an overview of the design and advantages of the developed instrument. The developed software and hardware are also introduced. Moreover, a typical applications of the instrument and its comparison with a digital point gage in laboratory channel (straight path, 90 degree bend and around a spur dike) are also presented.
Volume 11, Issue 3 (11-2011)
Abstract
Abstract :Side sluice gates are flow metering structures, which are used for controlling the flow from the main channel to the side channel. It is usually required to determine the discharge coefficient for estimation of the side sluice gate discharge. In order to study the influence of some important parameters on the discharge coefficient of side sluice gate, extensive experiments were conducted. The experiments were conducted in a re-circulating channel having a central angle of 180o, a centerline radius of RC = 2.6 m, and the width and height of 0.6 m. The ratio of radius of centerline of the channel to the width of the channel Rc/B was 4.33. The bend was connected to two straight upstream and downstream reaches. The upstream one was 7.2 m in length while the length of downstream one was 5.2 m. The bed and sides of the channel were made of glass and supported with metal frames. The side channel was set at different locations of bend (i.e. at the sections 53, 65, 90, 115 and 135 degree). The side sluice gate was made of Plexiglas and was set at the entrance of the side channel. The experiments were carried out for different gate openings, upstream depth of flow and location of the side sluice gate under free flow condition. The upstream discharge was measured by a digital flow meter, while the downstream discharge was measured using a calibrated triangular weir. The difference of upstream discharge and downstream discharge resulted to the sluice gate discharge. The results of experiments on a side sluice gate located in a 180 degree curved channel are reported. The variation of flow depth along the side sluice gate was studied. The influence of different parameters like: depth of flow, approach Froude number, side sluice gate opening and location of side sluice gate on discharge coefficient were investigated. It was found that increase of approach Froude number increases the discharge coefficient. Moreover, increase of relative flow depth h1/a increases the discharge coefficient. Here, h1 is the approach Froude number and a is the sluice gate opening. Maximum discharge coefficient was observed when the sluice gate was located at the section 150 degree in the channel bend. New equation for discharge coefficient of a side sluice gate in a 180 degree curved channel was developed. The discharge coefficient was found to be related to approach Froude number, location of sluice gate in the channel bend and the relative flow depth
Volume 12, Issue 60 (12-2024)
Abstract
Folk literature, including oral stories and folk poetry, are open narratives that each narrator uses according to his or her own intent. This genre, however, for reasons such as its humiliating title, the simplicity of the images, the use of the language of the masses, and elitism Persian literature, has not received much attention. In the constitutional period, however, with the change of the paradigm, of course, it was considered for political purposes and appeared as a rival discourse against the thousand-year-old discourse of classical literature. Folk literature was a constantly neglected "other" voice that found an unexpected opportunity to be heard in the new discourse. One of the poets who used this capacity to advance his political and ideological goals is Ahmad Shamloo. After Nima and perhaps more than him, Shamloo is the most prominent poet who has brought the realm of poetry into the public area in various ways; without neglecting the noble aspect of poetry. This approach is of course the result of his theory of literature, which considers it a social duty and commitment to justice and awakening the masses of people and raising children against oppression and injustice; therefore, by using the special codes of the mass people and children's legends, whether in the form of folklore poetry based on folk tales and legends or slang words and even compiling an Ketab e Koocheh, he has attempted to consolidate this ideology. This study, with the approach of cultural studies, reflects on the two contradictory sides of his metaphorical use of language and folk poetry: 1. Deconstructing the elitist approach to literature through defamiliarization with folk poetry, 2. Shamloo's use of children's language and discourse in folk poetry, which implies the sameness of the mass and the child and the need to be guided and led by a saviour.
Research Background
Research related to this study falls into two separate categories: 1. politics in Shamloo’s poetry, that sometimes contradictory views have been raised, only two cases are mentioned: Kamalizadeh (2016) in the book Politics in Modern Poetry, has addressed the two poems examined in this article solely in terms of the poet’s position and his political message, and Qaragozlou (2017) in the book of Tarikh e Talkh, which, of course, seems to have another definition of political poetry; he considers Shamloo’s Qat’nameh as a social thought that is different from political poetry.
A few researchers have also exclusively studied his folklore poetry; such as Salajeqeh (2010) in which she has examined the components of “travel and search” in two other folklore poems by Shamloo; in this study, “Baroon” and “The Story of a Man Who Had No Lips” are examined.
Kafashi (2011) has examined two poems by Shamloo. As its title shows, the study has no research problem. Furthermore, the research method is not scientific. Bahrampour (2010) has also examined Shamloo's four poems, in the category of folkloric poems that are reinterpretations of popular literature, a reinterpretation that in fact creates a neo-fiction and focuses on the role of “human being”.
Other works that have paid attention to the political themes of Shamloo's poetry have not addressed how it is integrated with folk poetry, and in particular the role of ideology as a central signifier or determining element, which is the subject of this study.
Goals, questions, and assumptions
The aim of this investigation is to explain the role and function of ideology in the aesthetics of Shamloo's folkloric-children's poetry, which, by referring to the theory of cultural studies and semiotics, addresses the semantic capacity and implications of this type of poetry. It answers these questions:
1. Why did Shamloo write folkloric-children's poetry alongside his formal poetry?
2. What is the function of this type of poetry and what are the semantic implications of its form?
The article's assumption was that this type of poetry was written to promote leftist ideology, but cultural studies theory emphasizes the prominence of the role of mass culture and the deconstruction of elite culture in literature.
Conclusion
Shamloo believed that in order to understand the literature of a land, one must be familiar with the language and culture of the masses of the people, and he considered this to be the beginning of such understanding. Moreover, his populist approach, which was the result of his lived experience and meetings and gatherings with the masses of people from different ethnicities and minorities, was not without influence in his connection with the Tudeh Party, but after breaking away from the party, he also took advantage of this vast opportunity to spread socialist ideas. Although Shamloo used vernacular in all of his poems, both this general use and his folk poetry simultaneously have a political function from the perspective of language, aesthetics, and content: 1. Contrasting the uncultured language of the people against the noble and refined language of classical poetry, 2. Contrasting the non-literary language of the people against the polished language of the Romantic poetry of the 1950s and the language of the New Wave (Mowj e No) poets of the 1960s, 3. The use of children's language, form, and music in political folk poetry with ideological and idealistic goals that implicitly imply the ignorance of both and require the awakening of the poet as a savior, 4. Breaking the monopoly of poetry's audience from the elite to the masses and summoning new audiences for poetry, namely children, in order to create a generation to fight oppression.
Research Background
Research related to this study falls into two separate categories: 1. politics in Shamloo’s poetry, that sometimes contradictory views have been raised, only two cases are mentioned: Kamalizadeh (2016) in the book Politics in Modern Poetry, has addressed the two poems examined in this article solely in terms of the poet’s position and his political message, and Qaragozlou (2017) in the book of Tarikh e Talkh, which, of course, seems to have another definition of political poetry; he considers Shamloo’s Qat’nameh as a social thought that is different from political poetry.
A few researchers have also exclusively studied his folklore poetry; such as Salajeqeh (2010) in which she has examined the components of “travel and search” in two other folklore poems by Shamloo; in this study, “Baroon” and “The Story of a Man Who Had No Lips” are examined.
Kafashi (2011) has examined two poems by Shamloo. As its title shows, the study has no research problem. Furthermore, the research method is not scientific. Bahrampour (2010) has also examined Shamloo's four poems, in the category of folkloric poems that are reinterpretations of popular literature, a reinterpretation that in fact creates a neo-fiction and focuses on the role of “human being”.
Other works that have paid attention to the political themes of Shamloo's poetry have not addressed how it is integrated with folk poetry, and in particular the role of ideology as a central signifier or determining element, which is the subject of this study.
Goals, questions, and assumptions
The aim of this investigation is to explain the role and function of ideology in the aesthetics of Shamloo's folkloric-children's poetry, which, by referring to the theory of cultural studies and semiotics, addresses the semantic capacity and implications of this type of poetry. It answers these questions:
1. Why did Shamloo write folkloric-children's poetry alongside his formal poetry?
2. What is the function of this type of poetry and what are the semantic implications of its form?
The article's assumption was that this type of poetry was written to promote leftist ideology, but cultural studies theory emphasizes the prominence of the role of mass culture and the deconstruction of elite culture in literature.
Conclusion
Shamloo believed that in order to understand the literature of a land, one must be familiar with the language and culture of the masses of the people, and he considered this to be the beginning of such understanding. Moreover, his populist approach, which was the result of his lived experience and meetings and gatherings with the masses of people from different ethnicities and minorities, was not without influence in his connection with the Tudeh Party, but after breaking away from the party, he also took advantage of this vast opportunity to spread socialist ideas. Although Shamloo used vernacular in all of his poems, both this general use and his folk poetry simultaneously have a political function from the perspective of language, aesthetics, and content: 1. Contrasting the uncultured language of the people against the noble and refined language of classical poetry, 2. Contrasting the non-literary language of the people against the polished language of the Romantic poetry of the 1950s and the language of the New Wave (Mowj e No) poets of the 1960s, 3. The use of children's language, form, and music in political folk poetry with ideological and idealistic goals that implicitly imply the ignorance of both and require the awakening of the poet as a savior, 4. Breaking the monopoly of poetry's audience from the elite to the masses and summoning new audiences for poetry, namely children, in order to create a generation to fight oppression.
Volume 13, Issue 2 (5-2013)
Abstract
Abstract: In this paper the experimental study of the flow pattern around a round wall jet has been carried out to investigate the effect of the bed roughness on the turbulence characteristics, including Reynolds stress and turbulence intensities. Measurements were conducted using the three-dimensional velocimeter, ADV and time series of the velocity components are used to investigate the variation of the turbulent flow parameters along the measuring domain. The results showed that by increasing the bed roughness, the streamwise and vertical turbulence intensities increase by downstream distance and for a specific bed roughness the streamwise turbulence intensity is higher than the vertical one. Furthermore, by going downstream from the jet entrance the bed shear stress reduces and by increasing the bed roughness, the bed shear stress has an increasing trend along the jet centerline. Location of the maximum bed shear stress does not change by changing the bed roughness.
Shahed Mirzamohammadi, Mojtaba Ghodsi, Y Hojjat, Soheil Talebian,
Volume 13, Issue 15 (Third Special Issue 2014)
Volume 13, Issue 15 (Third Special Issue 2014)
Abstract
In this article, the influences of different effective parameters on sensitivity of a magnetostrictive force sensor are investigated and then, a high sensitive magnetostrictive force sensor is designed and fabricated. Initially, the operational principles related to magnetostrictive force sensors are presented. Then, conceptual design of the sensor is illustrated and sensors geometry and applied materials are determined. In the next step, measurement of magnetic hysteresis and optimization of the magnetic properties through heat treatment are presented. To this end, magnetic hysteresis curves of not-annealed low carbon iron and annealed low carbon iron under different currents and magnetic hysteresis curve of bulk TERFENOL-D under different preloads and currents are obtained. Then, through numerical simulations using finite element method software, parameters affecting sensor sensitivity were identified and designed. Finally magnetostrictive force sensor is fabricated and its sensitivity and functional specifications are tested under different conditions. The magnetostrictive force sensor sensitivity and linearity error are found as 0.51mV/N and 2.8% FSO respectively, which is a higher value compared to similar magnetostrictive force sensors.
Volume 13, Issue 51 (7-2016)
Abstract
Bread is the main source of a large part of the energy, protein, minerals and vitamins required by humans. Aloe Vera is one of the oldest medicinal plants that beside of fiber, minerals, vitamins, amino acids and natural sugars, have antimicrobial agents, anti-inflammatory and antioxidant Therefore, its use helpful for the prevention and treatment of Alzheimer's, heart disease, digestive problems. This study examined the effect of addition of aloe vera powder in quantities of 1, 3, 6 and 9% (w / w based on flour) on the quality of Barberi bread, as well as changes in microbial, texture, color and water absorption properties of bread within 72 hours in order to produce the functional bread. The results showed that the adding of aloe vera powder, causing controlling the activity of microorganisms and mold and yeast, increase swelling power and reduce staling the bread. However, volume, brightness, Points smell, taste and the ability to chewing has declined. In general, investigation of breads characteristics in this study showed that the adding powder of aloe vera until 1%, causing improve the quality of shelf life and increase the healthly value of Barbari breads that is produced.
Volume 13, Issue 51 (7-2016)
Abstract
The main functions of the packages are: Physical protection, barrier protection, convenience and information. Tendency to minim process food products, quality, safety and preventing of food born disease and strict requirements in relation to consumer health caused ways to use antimicrobial agents in food packaging and prevent the development of microorganism growth. Active packaging is one the methods of efficient packaging, that protect safety and quality of foods. The material of these packages is a suitable base for adding a wide range of different combinations such as antimicrobial agents to them. Pursuant to this, movie bionanocomposite films of Bitter vetch seed’s protein with zinc oxide nanoparticles to produce an antimicrobial packages with %5 w/w of Bitter vetch protein isolate and 0.25, 1 and 2% zinc oxide nanoparticles. Glycerol was used as plasticizer. The mechanical and barrier properties of bionanocomposite films assessment and determined that the addition of zinc oxide nanoparticles as an antimicrobial agent to the protein film caused a sharp decrease of oxygen permeability through the films. The rate of water vapor permeability of bionanocomposite films decreased comparing with control film. The results indicated that lower levels concentrations of nanoparticles cause better functional properties of bionanocomposites films because of fewer particles coagulation. Effect of nanoparticles on the mechanical properties, tensile strength and modulus of elasticity were increased, but elongation of the film was reduced.
Volume 14, Issue 4 (12-2014)
Abstract
The sediment excluders are provided on the barrages or diversion weirs in the river pocket adjacent to the head regulator to minimize sediment entry in to the canal water. On rivers, the excluders have to deal with alluvial material being transportd by the river. Excessive sediment load can cause damage in a variety of ways which result in many serious problems such as meandering of stream, reduction of channel capacity, silting up of canal, damage to power units and obstruction to navigation. Different types of sediment extractors/ excluders, such as tunnel type, vortex tubes, rectangular settling basins and vortex type settling basins are ofthen employed for this purpose. A tunnel-type sediment excluder is commonly used at the headwork of a canal for preventing excess sediment entry in to the off-taking canal. In such type of excluders, the sediment-laden water, which flows mainly near the bed, is made to flow through the tunnels provided at the bed and the sediment-free water in the top layers is allowed to enter the off-taking canal. It may be then discharged back into the river downstream through the undersluice bays. Comparatively sediment-free water in the top layers is allowed to enter the canal. The only hydraulic principle utilized in its design is that energy loss is kept to a minimum and a minimum velocity of flow is ensured through the tunnel for the non-deposition of the coarse material In the method recommended by Garde and Pande (1976) and Kothyari (1999) for design of tunnel-type sediment excluders, the main objective is to design a tunnel which is able to flush maximum of sediment load through the tunnel by minimum of excluder discharge and minimum of blockage hence considering all restrictions and constraints for design of such structures. In the current research it was tried to achieve an optimum design using fuzzy logic abilities and searching the solution domain by an intelligent search method (Genetic Algorithm) which is able to pass the local optimums and find the global optimum. GA considers many points in the serach space simultaneously and has been found to provide a rapid convergence to a near optimum solution in many types of problems. Then optimal designs of GA and Direct-Search method were compared with some of projects in India (i.e. Ganga, Sarda and Eastern Kasi) which were design using traditional methods. A fuzzy AHP (Analytic Hierarchy Process) approach was used for assessing the weight of efficiency, blockage and sediment excluder discharge in goal function. AHP is particulary usefull for evaluating complex multi attribute alternatives involving subjective criteria.The fuzzy AHP approach allows a more accurate description of the decision making process. The triangular fuzzy numbers were used to build the comparision matrices of AHP based on pairwise comparision technique.The results show that the Genetic Algorithm method gives better results in compare with direct search technique. The result also show that the efficiency of tunnel-type sediment excluders are high enough in both optimal design and traditional methods, but sediment blockage percent in propose optimal design is less than correspond design values using
Volume 14, Issue 4 (1-2015)
Abstract
In this paper, a new configuration for delta conversion UPS is proposed, which could help the system for better utilization of the UPS inverters. In this configuration, parallel and series inverters of the conventional delta conversion UPS, under the grid fault conditions, are connected in parallel which help to share the load power and this results in utilizing the series inverter during fault mode. Therefore, using this configuration not only decreases the total capacity of the UPS inverters, but also decreases the system total cost. In the proposed configuration, two inverters have the same sizes and specifications which results in the system modularity that simplifies its implementation and maintenance and reduces the manufacturing and life cycle cost of the UPS system. In addition, the proposed configuration increases the system reliability. To illustrate proper operation of the proposed configuration, some simulations are carried out under the different conditions. The given simulation results validate appropriate operation of the proposed configuration.
Yossef Hojjat, Keyvan Kakavand, Mojtaba Ghodsi, Ali Asghar Maddah,
Volume 14, Issue 12 (3-2015)
Volume 14, Issue 12 (3-2015)
Abstract
In this paper a new model is developed to describe the response of Magneto-rheological fluids (MRF) in transient state. The models which are developed so far, cover the steady-state flow, or address the transient state, with step-wise input electrical current and constant shear rate. In this paper, a new model for transient state of MRF is developed in which the input electrical current is an exponential function in different values of shear rate. Due to the magnetic inertia caused by the inductance of the coil, the real magnetic flux density could not be step-wise. Hence, compare with the other models, this model is in well agreement with reality. To verify the presented model and study the fluid properties as input parameters, an experimental coupling is designed and fabricated. The coupling applies magnetic field perpendicular to shear direction, and measures the shear stress as a function of time. The results of the proposed model show acceptable agreement with experimental observations. According to experimental and theoretical results, the presented model is applied to a controllable torque coupling and acceptable results were obtained.
Yousef Hojjat, Ali Asghar Maddah, Mojtaba Ghodsi, Soheil Talebian, Mohammad Reza Ashoori,
Volume 14, Issue 16 (Forth Special Issue 2015)
Volume 14, Issue 16 (Forth Special Issue 2015)
Abstract
The purpose of this paper is obtaining an optimal arrangement of permanent magnets in a non-contact eddy current damper in order to achieve the maximum damping coefficient (c) among dampers with the same dimension. Magnetic theory and eddy current equations have been employed and solved by finite element numerical method. The dominant damping parameters and the optimum ratio of the ferrite core and the permanent magnet for the specific dimension have been achieved. A damper with the dimensions obtained from design is manufactured in order to verify the result of simulations. A setup also is designed and manufactured to verify the damping coefficient. The damping coefficient of simulation and experimental setup is 69.50 and 68.37 respectively which shows a close correlation between simulation and experiment results. The damping coefficient of the designed damper has been increased by 22.5% compared with a same dimension damper. Furthermore, frequency response is obtained by MATLAB software and a decrease of vibration amplitude in eddy current damper has been investigated. The result showed 20 dB reduction in the peak amplitude of frequency response in the designed damper.
Volume 15, Issue 2 (7-2015)
Abstract
Weirs possess an essential role in dam safety and should spill floods with high return period. The designers can enhance the width of the weirs to increase the discharge capacity. But this has sometomes topography and economic limitations. Arced weirs can be considered as an alternative. A arced weir is a arcuate of a circle in plan-view that provides an increase in crest length for a given channel width that increas the flow capacity for the same head. Also when modification and capacity increase in existing spillways are necessary, this structure is recommended. In this paper, the hydraulic performance of arced weirs located in a reservoir has been studied experimentally. Firstly, dimensionless parameters affecting the performance of arced weirs is introduced using Buckingham π theorem. Then effect of arc angle (θ) and head water ratio (H0/P) on hydraulic performance of arced weirs was experimentally investigated and hydraulic performance of the tested arced weir geometries was compared with a linear configuration. For this purpose, Arches with different radius of curvature from linear to semi-circular configurations ( ) and various head water ratio Were studied. To simulate reservoir conditions, a reservoir simulator was designed and built. Laboratory observations show that the converging of flow over a arced weir causes a locally bulge in the downstream of the weir. This phenomenon was named as flow mound. Results show that arc angle (θ) and head water ratio (H0/P) have a direct effect on the flow mound and an increase in each of them leads to mound height rise. The head-discharge relationship for arced weirs was determined by using a general form of the rectangular weir equation. Data from physical models were used to determine discharge and upstream head for the flat crested weirs installed in the reservoir. from discharge curves, it was found that with increasing angle of weir, that provide an increase in crest length for a given channel width, flow capacity increases for a given upstream head. Discharge coefficients as a function of H0/P for arced weirs are also presented and is compared with linear configuration. The results show that with increasing H0/P, discharge coefficient is declined for each tested configuration. Also with increasingθ , that leads to greater convergence of flow passing over the weirs, discharge coefficient decreases. Efficiency parameter is defined as the ratio of discharge of arced weir to that of liner weir with a same width. From efficiency curves it can be understood that the semi-circular weir can improve efficiency up to about 45%. However for all tested weirs , efficiency decreases with increasing H0/P and it gets close to 1. Finally, based on the results and limitations of this study, a methodology for the design of arced weirs located in the reservoir is presented. By using this method, the geometric parameters if an arced weir that is able to pass a certain flow rate for a given hydraulic head, will be determined.
Hamidreza Ziaiefar, Milad Amiryan, Mojtaba Ghodsi, Farhang Honarvar, Yousef Hojjat,
Volume 15, Issue 5 (7-2015)
Volume 15, Issue 5 (7-2015)
Abstract
In this paper, we proposed a practical method for classifying damages in pipes and plates using ultrasonic guided waves. The A-scan Pulse-Echo lamb wave ultrasonic tests used in this study. Tests accomplished on isotropic 1050 Aluminum with 0.4 mm thickness. Damages studied here were corrosion and crack which is common in pipe lines and steel structures like vehicles body or aerospace structures. This investigation is done in three steps. First step, experimental testing (making standard sample, lamb wave tests), second step, signal processing (window function, normalizing, wavelet function), third step, using the proper algorithm for classification. In first step, 206 ultrasonic lamb wave tests are measured on standard damaged samples (on pipe and plate) and the signals digitalized. After that, these signal processed and classified by classification algorithm. In this the classification algorithm is the support vector machine (SVM). In machine learning, support vector machines are supervised learning models with associated learning algorithms that analyze data and recognize patterns, used for classification and regression analysis. The results show that the corrosion damage can be distinguished from crack damages with 99% accuracy by proposed algorithm.
Volume 15, Issue 5 (Supplementary Issue- 2015)
Abstract
Abstract In this paper, flow and scour pattern around submerged and attracting T head spur dike in a straight bend has been studied. For measuring 3D velocities and bed topography, Vectrino+ and Point gauge machines were utilized. 3D velocities were measured in rigid bed state. Flow pattern experiments were conducted in a way in which after installation of spur dike in their place the sediments of the bed were flattened and then the sediments around the spur dike were covered with a thin layer of cement grout using anairbrush. After 6 hours, once the cement grout dried, the experiments are initiated. During velocity record times no scour was observed. In this research, electrical current was plotted in lateral and horizontal plans and flow pattern was studied. The findings of this research showed that the maximum scour in attracting spur dike is stronger than that of repelling spur dike and in both states it occurs in the edge of upstream wing of spur dike. Besides, flow pattern results suggest presence of a separation plane in upstream spur dike where a part of flow acts as up flow and another part acts as down flow. Moreover, flow and scour pattern in lateral, vertical, and different other plans were presented in this research. Furthermore, the finding of this study revealed that dimensions of downstream scour hole for attracting spur dike are larger. The length of this hole for attracting and repelling spur dike is 3.8 and 3.1 times to the effective length of spur dike. This suggests stronger effect of attracting spur dike on downstream flow. Besides, the width of scour hole in repelling spur dike (4.2 times to the effective length of spur dike) was larger than that of attracting spur dike (5 times to the effective length of spur dike). The length of sediment ridge in the attracting spur dike, due to its stronger effect on its downstream area, was larger (20 times to the effective length of spur dike) than that of repelling spur dike (16.4 times to the effective length of spur dike). Moreover, through this research it was found that the down flow area in upstream spur dike in repelling spur dike is larger than that of the attracting spur dike - 0.77 and 1.4 times to the effective length of spur dike for attracting and repelling spur dike, respectively. This length corresponds with the vastness of down flow. Also, the length of circulation zone in downstream of attracting and repelling spur dikes were 3.8 and 3.1 times to the effective length of spur dike, respectively and this length is in consistent with length of scour hole in downstream spur dike in vicinity of the spur dike. Finally, through this research, it was found that the center of clockwise vortex developed in downstream of repelling spur dike, compared to the attracting spur dike, is closer to the spur dike and due to initiation of deposition in a distance closer to the spur dike in repelling spur dike.
Yousef Hojjat, Mohammad Reza Sheykholeslami, Mojtaba Ghodsi, Hesam Sadeghian,
Volume 15, Issue 9 (11-2015)
Volume 15, Issue 9 (11-2015)
Abstract
In giant magnetostrictive transducer, Young modulus of the core considerably alters with changing its magnetic level. Young modulus change in Terfenol-D core has the highest value. This effect, changes the resonance frequency and mode shapes of the transducer. This subject in Terfenol-D resonance transducer is studied in this paper. For this purpose, a resonance Terfenol-D transducer has been designed and fabricated. Node locations in the transducer are considered to add pre-load and bias mechanisms. Effect of Young modulus change on resonance frequency and mode shape were studied both analytically and by ANSYS FEM software. Range of resonance frequency change in the first mode is 1000 Hz and in the second mode is 100 HZ. Mode shapes changes are limited for both modes. In 40kA/m magnetic field bias, Results from analytical and FEM simulation were verified with experimental results. Resonance frequency in this bias is 3100 Hz for the first mode and 8252 Hz for the second mode. Results have acceptable agreement with experimental results. Moreover, in this bias magnetic field, impedance responses between first and second modes are compared. Results show that selecting second mode is preferable for reducing disturbance of Young Modulus change on vibrational behavior.