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Issue Info: 
  • Year: 

    2021
  • Volume: 

    14
  • Issue: 

    3
  • Pages: 

    921-933
Measures: 
  • Citations: 

    0
  • Views: 

    44
  • Downloads: 

    3
Abstract: 

The aim of the present paper is the study of interaction of the abrupt wave with vertical and inclined RECTANGULAR OBSTACLES. For this purpose, in the first step, two experiments have been done. The tests were performed with smooth RECTANGULAR cross-section channels, and related data were extracted using digital image processing. Flow behavior was recorded with one adjacent CCD camera through the glass walls of the entire downstream channel. In the second step, the numerical study has been done by a mesh-free particle Lagrangian method (Incompressible Smoothed Particle Hydrodynamics, ISPH) and a mesh-based Eulerian method (Finite Volume Method with Volume of Fluid surface tracking approach, FV-VOF). The capabilities of the numerical methods in simulation of the sudden variations free surface flows have been assessed. A comparison between the computed results and the experimental data shows that both numerical models simulate the mentioned flows with reasonable accuracy.

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Issue Info: 
  • Year: 

    2017
  • Volume: 

    40
  • Issue: 

    SUPPLEMENT 1/1
  • Pages: 

    27-37
Measures: 
  • Citations: 

    0
  • Views: 

    873
  • Downloads: 

    0
Abstract: 

Vortex is created when flow possed a group of OBSTACLES such as bridges piers, docks and etc. Transverse wave is created by overlapping the vortex that created behind OBSTACLES and due to adapting of the vortexes frequency with natural frequency, of channel dimension. All experiments in this study are done on a flume with 6m in length, 0.72m in wide and 0.6m in height. As OBSTACLES in the flow were, wooden cubic OBSTACLES. The discharge of flow was equal to 20 lit/s and the regime of flow was sub-critical. In all arrangements by reducing the height of submerged OBSTACLES and increasing their submergence ratio, gradually wave amplitude of type 1 and type2 is reduced and the maximum amplitude was also reduce until it completely disappears. For example, in test No.1 with 21% submergence any wave was not observed. also the maximum amplitude in the non-submerged situation was more than the submerged sitoation. For example, in test No.1 the maximum amplitude of wave is type 1 was 4.3 mm, This value reduced to zero in the submerged situation. Finally a relationship is proposed to estimate of amplitude of transverse waves for submerged case.

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Issue Info: 
  • Year: 

    2017
  • Volume: 

    17
  • Issue: 

    4
  • Pages: 

    331-340
Measures: 
  • Citations: 

    0
  • Views: 

    582
  • Downloads: 

    0
Abstract: 

In this article, mixing in the combined electroosmotic/pressure driven flows of non-Newtonian fluid in a micro channel with RECTANGULAR OBSTACLES and non-homogeneous ζ-potential has been studied numerically. The non-Newtonian behavior of the fluid is considered for the flow field using power law rule. Also, the nonlinear Poisson-Boltzmann equation is used to model the distribution of ions across the channel and the electric potential. Numerical solutions of coupled equations of momentum, electric field and concentration field are performed by means of finite element method. In this study, the effects of various parameters such as pressure gradient, rheological behavior of the fluid and the geometrical and physical parameters of OBSTACLES on the mixing quality are investigated. The results indicate that applying adverse pressure gradient to the flow, the dilatant behavior of the fluid, as well as the height of barriers, is highly effective in the enhancement of the mixing quality within the microchannel. It is found that for microchannels with heterogeneous V-potential, increasing the length of OBSTACLES significantly increases the mixing efficiency while for the microchannels with homogeneousV-potential, barrier length has a slight effect on mixing efficiency.

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Issue Info: 
  • Year: 

    2024
  • Volume: 

    13
  • Issue: 

    25
  • Pages: 

    3-32
Measures: 
  • Citations: 

    0
  • Views: 

    15
  • Downloads: 

    0
Abstract: 

In this research, in order to investigate the effect of the piezoelectric patch which is used as a sensor or actuator in rotating flexible structures such as a helicopter blade, the free vibrations of the rotating RECTANGULAR sheet with and without the piezoelectric patch have been presented. First-order shear deformation theory is considered for plate displacement and piezoelectric field. Considering the effect of Coriolis acceleration, centrifugal acceleration and centrifugal in-plane forces, the equations of motion are derived from Hamilton's principle and the electromechanical couple equation is obtained from Maxwell's equation. For piezoelectric, two electrical conditions, open circuit and closed circuit, which are used in sensors and actuators, respectively, have been considered. The equations are discretized with the help of the numerical method of generalized differential squares and the matrices of inertia mass, eccentricity, Coriolis and stiffness matrix are obtained. Natural frequency values for beam and rotating plate have been compared in Abaqus software. Also, the values obtained from the numerical solution in MATLAB have been verified with articles and ABAQUS, which have high accuracy. The effect of parameters such as hub radius, rotation speed, sheet thickness, aspect ratio, piezoelectric patch thickness and applied voltage on the natural frequency of the system has also been investigated.

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Author(s): 

Rahbari Ghazani Rasoul

Issue Info: 
  • Year: 

    2023
  • Volume: 

    17
  • Issue: 

    45
  • Pages: 

    267-282
Measures: 
  • Citations: 

    0
  • Views: 

    119
  • Downloads: 

    15
Abstract: 

This study explores the distinguished Persian Sufi mystic Shaykh Maḥmūd Shabestarī’s Golshan-e Rāz, or The Rose Garden of Mystery. Adopting a hermeneutic approach, it scrutinizes the intricate spiritual journey towards divine realization delineated in Shabestarī’s poetry, utilizing qualitative content analysis of original texts and interpretations by scholars such as Lāhījī and Ibn Turka Iṣfahānī. The main question the paper addresses is this: “How can the spiritual journeyer overcome OBSTACLES—particularly ‘otherness’—and achieve unity with the divine Essence within the framework of Islamic mysticism, as interpreted through Shabestarī’s teachings in Golshan-e Rāz?” To answer this inquiry, the paper addresses pivotal questions concerning Shabestarī’s depiction of the spiritual journeyer’s path, its stages and challenges, and the critical role of the human form in divine manifestation. The study underscores the necessity of overcoming duality and distinction, alluding to the transformative nature of the journey that necessitates self-purification and the cessation of otherness. Findings from this study provide an enriched understanding of Shabestarī’s thought, contributing to the discourse on Islamic metaphysics. It presents valuable insights into the spiritual journeyer’s path, offering a comprehensive interpretation of the challenges, practices, and transformative experiences leading to divine realization and unity.

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Issue Info: 
  • Year: 

    2023
  • Volume: 

    11
  • Issue: 

    2
  • Pages: 

    75-97
Measures: 
  • Citations: 

    0
  • Views: 

    169
  • Downloads: 

    30
Abstract: 

ABSTRACT With the expansion of inefficient tissues, "Urban regeneration" has been objectified as a solution for developing cities in different physical, social and economic dimensions. Despite the development of the guidelines for urban regeneration projects, these projects in Iran still have challenges in the stage of realization and implementation. This article aims to identify the "challenges and causes of non-realization of urban regeneration projects in Iran" and analyse the research conducted in this field with a qualitative approach. For this purpose, a meta-analysis of 23 articles in the field of problems of urban regeneration projects in Iran was carried out. The challenges raised in the AtlasTI software were extracted with the help of open and axial coding. In the following, 100 codes were determined in the form of 10 groups or general categories. In the end, the OBSTACLES to the realization of urban regeneration projects in Iran were given. According to the obtained results, the weak presence of non-governmental organizations, the problems of preparing plans, institutional and management problems, and the weakness of participation are the four most important and frequent challenges in the research related to the realization of urban regeneration projects in Iran Extended Abstract Introduction The trend of urban population growth and the expansion of inefficient urban fabrics along with the increasing immigrant population to the cities makes the planners think of filling the existing urban fabrics with excessive density and land use change, instead of the city horizontal development with regard to the urban sustainable development prism. Poor housing, low per capita services, lack of necessary infrastructure, low quality of life, economic stagnation and functional inefficiency, unorganized physical-spatial structure, high vulnerability to earthquakes, loss of social status, and various social problems exemplify the typical challenges of such deteriorated areas. Deterioration of the urban fabric has prompted the emergence of various urban development policies among which regeneration as an overarching approach characterized by its economic, social, environmental, physical, ecological dimensions and components including quality of life, justice, revitalization and participation. This concept, as an urban development policy, has been defined and applied in the vulnerable and deteriorated areas of cities in recent years. Started from physical redevelopment in the Second World War and passing through policies concentrated on social and economic welfare, urban regeneration policies moved towards the participation of local residents and the creation of sustainable places in recent decades. However, taking into consideration the manifestation challenges of urban development plans, in the existing literature, urban regeneration challenges have been less comprehensively investigated. This paper aims to identify the "challenges and causes of lack of urban regeneration plans manifestation in Iran" based on the review and analysis of the research conducted in this field with a qualitative approach in response to this question: "What are the challenges and OBSTACLES to the manifestation of urban regeneration projects in Iran?”   Methodology This research aims to identify "challenges and OBSTACLES to the manifestation of urban regeneration projects in Iran" through a meta-analysis of the research conducted in this field. Conducting a systematic search in Magiran, comprehensive humanities portal, and Google Scholar databases using the Boolean logic search used the keyword (challenges) AND key phrases (‘manifestation of plans’ AND ‘urban regeneration in Iran’) resulted in more than 70 Persian papers, 2 English papers, and 2 English theses. The reviewed studies included research and review papers, case study research, and the special issue of urban regeneration policy of Haft Shahr Journal. The geographical scope of the investigated studies covers the historical contexts of Iran, and metropolises such as Tehran, Tabriz, Shiraz, and Isfahan. Reviewing the abstracts, 23 studies were selected among which the research focusing on the different types of regeneration, and evaluation of urban regeneration indicators were excluded from the research process. To conduct meta-analysis after a comprehensive review of each study, open and focused coding of challenges was done through Atlas.ti software (version 8), and the OBSTACLES to the manifestation of the plans were extracted. Coding process continued until the saturation was reached. Finally, the 115 codes obtained was reduced to 100 through integrating similar codes. Then, all the codes were categorized into 10 categories, and a comprehensive model of "challenges of manifestation of urban regeneration projects in Iran" was presented.   Results and discussion Based on the conducted review, the recognized problems with emphasis on the different aspects of urban regeneration projects are: 1) Weak presence of non-governmental organizations (18 codes); 2) Problems of preparing plans (17 codes); 3) Institutional and managerial problems (14 codes); 4) Weakness of participation (13 codes); 5) Duration and financial problems of urban regeneration plans (10 codes); 6) Problems of urban regeneration plans process (8 codes); 7) loss of identity of fabrics in the preparation of the plan (6 codes); 8) Lack of context-oriented approach (7 codes); 9) inefficient evaluation of plans (4 codes); 10) lack of social and specialized training for citizens and officials (3 codes). The lack of endogenous theory and insufficient knowledge of the environment and residents obstacle the manifestation of urban regeneration plans. Despite pretending the use of non-governmental organizations, the relevant law weaknesses, and the lack of belief in the effectiveness of it has led to disregard of the participation of non-governmental organizations in practice in the process of preparing and implementing development plans resulting in an inadequate context for manifestation of urban regeneration plans. In addition, the government supervision on NGO’s in the way of achieving independence has also caused limitations for their interplay. In terms of the issues in the preparation of plans, more emphasis on the physical and economic dimensions and the purely physical view, and the lack of attention to the social and cultural consequences, along with the loss of the community identity, are the factors of the failure of the plans to achieve the expected results. The lack of coordination between programs and multiple decision-makers led to the institutional confrontation instead of interaction. In this regard, the necessity of an integrated and comprehensive approach to urban regeneration has been acknowledged in the reviewed studies. NGO’s can play an effective role in communicating with citizens, educating citizens and informing them. It is also necessary to have the participation of the private sector and other organizations involved in the field of urban development in addition to public participation in all steps of preparation, implementation and occupation of projects and development plans. In the absence of a context-oriented approach in the preparation and implementation of urban regeneration plans in Iran with blind imitation of western models and the existence of limited urban infrastructure, following consequences are inevitable: uncertainty in terms of time, cost and site preparation before the implementation of the plan; lack of definition of urban regeneration plans in the different scales, neighborhood, region and city; and the uncertainty of the relationship between these plans and other urban development plans. As such in the current inadequate conditions driving the process of preparing plans, the possibility of implementing new policies and plans, is low and the implemented plans like many other urban development plans in Iran, are inefficient in the absence of the post occupancy evaluation.   Conclusion Based on the results, four priority challenges in the manifestation of urban regeneration plans in Iran include; the weak presence of non-governmental organizations, the problems of preparing plans, institutional and managerial issues, and the weakness of participation. "The weak presence of non-governmental organizations" has been mentioned as the first challenge in most reviewed studies (Ahmadifar et al., 2014). Regarding the "participation of citizens" even though in the set of laws and regulations of sustainable urban regeneration, promotion of citizenship culture, participation, and cooperation of local institutions are highlighted, the residents are not welcomed in practice. On the other hand, the lack of people's participation in the preparation and implementation of plans has made any urban regeneration actions fail or achieve to its partial goals. In this regard, the results of the previous comparative comparisons have shown that the lack of laws and regulations supporting participation in various fields is of the key factors (Nourian and Ariana, 2011, Shafie Dastjerdi and Sadeghi, 2016). The problems of preparing plans, institutional and managerial issues, ranked as the third and fourth issues in this study, have been emphasized in previous studies as well (Kalantari Khalil Abad et al., Pakro and Sattarzadeh, 2014, Izadi et al., 2019). Therefore, prioritizing the challenges raised by experts and determining operational strategies to solve them are issues that can be addressed in future studies.   Keywords Urban regeneration plans, manifestation, meta-analysis   Funding There is no funding support.   Authors’ Contribution All of the authors approved the content of the manuscript and agreed on all aspects of the work.   Conflict of Interest Authors declared no conflict of interest.

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Issue Info: 
  • Year: 

    2008
  • Volume: 

    19
  • Issue: 

    1
  • Pages: 

    123-131
Measures: 
  • Citations: 

    0
  • Views: 

    1389
  • Downloads: 

    0
Keywords: 
Abstract: 

Packing RECTANGULAR shapes into a RECTANGULAR space is one of the most important discussions on Cutting & Packing problems (C&P); such as: cutting problem, bin-packing problem and distributors pallet loading problem, etc. Assume a set of RECTANGULAR pieces with specific lengths, widths and utility values. Also assume a RECTANGULAR packing space with specific width and length. The objective function is, to pack the pieces into the space in Order to get the maximum sum of utility value of the packed pieces. To generate the related packing pattern this paper proposes a new formulation metl10dbased on the column generation, approach. In this method one each cycle of the algorithm; a one-dimensional pattern is generated based on the shadow prices 'Of the Simplex method. The set of generated one-dimensional patterns are used: to construct the two-dimensional packing pattern. Also, the proposed model and the present models in the.state-of-1beart have been compared.

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Issue Info: 
  • Year: 

    2023
  • Volume: 

    12
  • Issue: 

    3
  • Pages: 

    143-163
Measures: 
  • Citations: 

    0
  • Views: 

    37
  • Downloads: 

    6
Abstract: 

We first prove that there always exists a maximal RECTANGULARly dualizable graph for a given RECTANGULARly dualizable graph and present an algorithm for its construction. Further, we show that a maximal RECTANGULARly dualizable graph can always be transformed to an edge-irreducible RECTANGULARly dualizable graph and present an algorithm that transforms a maximal RECTANGULARly dualizable graph to an edge-irreducible RECTANGULARly dualizable graph.

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Author(s): 

AKBARZADEH S.

Issue Info: 
  • Year: 

    2013
  • Volume: 

    13
  • Issue: 

    6
  • Pages: 

    43-51
Measures: 
  • Citations: 

    0
  • Views: 

    678
  • Downloads: 

    0
Abstract: 

Due to the energy concerns, it is always desired to run the mechanical elements under optimized operating conditions. Many lubricated mechanical elements such as gears, rolling element bearings, cam and followers etc. usually operate under mixed-lubrication regime. In this regime, both the lubricant film as well as the asperities contribute in carrying the load. The life span of these elements is divided into two regimes: running-in and steady-state. In this research an efficient model has been presented to predict the variation in asperities height during running-in. The predicted results are verified with experimentally-obtained published data. A parametric study on the effect of operating conditions such as load and speed as well as initial surface roughness and material hardness on the roughness variation during running-in has been conducted.

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Author(s): 

hadi asgari hadi asgari | asgari hadi

Issue Info: 
  • Year: 

    2022
  • Volume: 

    1
  • Issue: 

    68
  • Pages: 

    65-82
Measures: 
  • Citations: 

    0
  • Views: 

    88
  • Downloads: 

    0
Abstract: 

The purpose of the current research was to investigate the OBSTACLES to the implementation of school-based management in Iran's educational system based on the interpretive structural modeling approach. The research method was a modeling study. The statistical population of the research was specifically the academic staff members of the university, 25 of whom were purposefully selected from the desired cases. The data collection tool was a researcher-made self-interactive questionnaire. In order to measure and evaluate the validity of the questionnaire, the criterion of content validity was used. The content validity of the questionnaire was 0.96. The data analysis was done with interpretive structural modeling method. The results of the research showed that 9 factors play a role as barriers to school-oriented management. Also, the results showed that financial OBSTACLES (the cost of school-oriented management), socio-cultural OBSTACLES and political OBSTACLES (political focus on schools by the central government) as key independent variables have high influence power and low dependence. Also, the results showed that the lack of belief in the professional competence of school administrators, the lack of infrastructure facilities, the emphasis of upper management on the supervision and control of schools, and the lack of cooperation of local communities with school-based management as the linking variables with the greatest power of influence and the greatest power of dependence. and the centralism in the education system of the country and the lack of legal powers to school managers and staff as dependent variables have high dependency power and low influence power.

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