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Showing 13 results for Gholipoor


Volume 4, Issue 4 (winter 2024)
Abstract

Problem: Residents of residential complexes in urban areas face all kinds of sounds every day. Most of these hundreds are very noisy and painful in traffic centers.
Target: The aim of the current research is to evaluate the satisfaction of the residents of Tabriz railway neighborhood from the perspective of environmental acoustic comfort.
Method: The current research method is descriptive-analytical with practical purpose. The statistical population of the research is 32,936 residents of the Tabriz railway neighborhood. The sample size was 380 people using Cochran's formula. For the validity of the questions, face validity was used and Cronbach's alpha was used for reliability. To analyze the data, structural equation method and TOPSIS and FTOPSIS techniques from Spss and Amos software were used.
Result: The results showed that among the factors affecting the acoustic comfort of the residents of the Tabriz railway neighborhood, the physical index had the greatest impact, followed by the acoustic and social indicators. Also, the results showed that in terms of the ranking of the koi in terms of acoustic comfort in terms of noise pollution, Ittahad alley got the highest noise pollution, followed by Niloufar alley and Shaghaig koi, the second and third respectively As a result, with proper design and use of form, facade and materials in terms of architectural acoustics, noise pollution can be reduced to a great extent in Tabriz Railway neighborhood and help to improve the quality of acoustic comfort of the residents.              

Volume 5, Issue 1 (4-2015)
Abstract

In recent years, Transmit and distribute organizational knowledge among employees which leads to functional synergistic in organizations, has found particular importance. Managers also have shown further interest in this subject, so more research has been leaning to the field. Reviewing literature showed that most research has been done on the subject of knowledge-sharing in organizations and there is no research has been done in Iran with the approach of knowledge hiding. Therefore the main issues of this study are factors causing the phenomenon of knowledge hidingin in organizations based on solutions. Software companies and professionals formed the research population. Grounded theory used based on 17 categories which formed a conceptual model which is presented in the paper.

Volume 6, Issue 2 (9-2016)
Abstract

The vast amount of existing resources which identify and describe only one part of the wide system of human resources risks, compared with the limited resources which address this issue in a systematic and multi-dimensional way, show the lack of holistic approach in this field of study. A two-dimensional framework is introduced in the present study in order to identify and categorize human resources risks. Three basic sources were provided to present this framework. First, history, models, perspectives and researches in the human resource risk field were extensively studied. Then, applying the results of this step and through semi-structured interviews with experts of three key organizations in the power industry, components and related indicators of the main aspects of human resource risks were identified. Using judgment and snowball sampling, interviews with experts were continued until theoretical saturation. Data extracted from interviews were analyzed using qualitative theme analysis method and QSR Nvivo software and 5 main themes, 14 sub-themes and 60 concepts of human resource risks were identified. The results of this analysis contributed to form a more complete view of human resource risks. Finally, according to the researchers’ analysis and judgment and using the results of previous steps, the research framework was introduced. The proposed framework consists of two strategic reference points. One of them explains the nature of risk and the other considers risk spotlight. The proposed framework could be a proper basis for researchers and administrators to identify and classify human resource risks.

Volume 10, Issue 2 (Spatial Issue on Persian Gulf 2021)
Abstract

In this study, coastal sediments of Qeshm, Bandar Khamir and Bandar Laft regions in Hormozgan province were studied to determine the level of contamination of heavy metals lead, nickel, zinc, iron and copper by natural processes or human activities. In order to identify environmental pollutants caused by heavy metals, shovel sampling was performed from the sediments of these areas to measure the concentration of heavy metals and determine the enrichment index. The location of the samples was determined using a GPS device and sampling of surface sediments (tidal zone) was performed at 30 stations in the study areas. Atomic absorption of flame spectrometry was used to determine the concentration of heavy metals. The results showed that the mean concentrations of heavy elements lead, nickel, zinc, iron and copper in all sampling stations showed a significant difference (p<0.05). In terms of concentration of studied elements in Qeshm region (copper: 33.76 ± 1.88, zinc: 85.44 ± 2.75, lead: 31.79±  1.23, nickel: 34.17 ± 2.29 and Iron: 38000±691.21 μg/g) compared to Bandar Khamir (copper: 26.84 ± 2.30, zinc: 77.54 ± 2.12, lead: 24.71±  1.37, nickel:25.82± 1.30 and iron: 36810± 482.882 μg/g) and Bandar Laft (copper: 22.74± 2.42, zinc: 65.22±2.61, lead: 19.93± 1.32, nickel: 21.70±2.06 and iron: 35560±1014.56 μg/g) had higher contamination. The results also showed that the metal enrichment factor is low in all sediment samples and in terms of Müller geochemical index, the degree of soil contamination is in the category of non-contaminated soils.

Volume 10, Issue 4 (3-2021)
Abstract

This research aims to provide a new product development model with an emphasis on environmental considerations and consumer participation. The model design was based on the grounded theory approach. The statistical population of this study includes all new product development experts in the food industry (including executives and academics) and thirteen experts selected by the snowball method. Results showed that the primary phenomenon involves activities and actions taken to develop a product based on environmental considerations and with the participation of consumers. The effective causes of new product development are divided into three categories: market, customer, and technical factors. The underlying conditions for product development are classified into two categories of infrastructure and capabilities. Also, penetrating interventionists were divided into three categories of cultural factors, risk management, and supportive factors. In addition, new product development includes three mechanisms: marketing, commercialization, and green design. The results of the product development model design emphasize on consequences of economic benefits and non-economic benefits.
Ahad Gholipoor, Hamid Baseri, Mohsen Shakeri,
Volume 14, Issue 1 (4-2014)
Abstract

The near dry EDM process uses a mixture of a liquid and a gas as dielectric medium. In this study, near dry EDM process at three levels of discharge energy and with two brass and copper electrode was studied to investigate the effects of tool material on machining performance. Also, the Taguchi method of design of experiments technique was employed to study the effects of nonelectrical parameters such as tool rotational speed, liquid flow rate, gas pressure and also discharge energy on material removal rate (MRR), electrode wear ratio (TWR) and surface roughness (SR) and also the analysis of variance (ANOVA) was employed to find the most important factors effecting MRR, TWR and SR. The results showed that copper electrode has higher MRR and lower TWR as compared to brass electrode. Also the analysis of main effect plots obtained by Taguchi method indicated that MRR and SR is enhanced by increasing water flow rate and discharge energy and also increasing gas pressure leads to lower TWR. The ANOVA results showed that discharge energy is the most important factor influencing MRR, TWR and SR.
Ahad Gholipoor, Vahid Zakeri Mehrabad, Ata Hejavari,
Volume 14, Issue 10 (1-2015)
Abstract

In this paper, in order to avoid the problems induced by cutting liquids like higher cost, environmental pollution and dangerous for operator health in milling process and also using the benefits of them such as increasing tool life and machined surface quality, machining by minimum quantity of lubrication (MQL) or near dry lubrication was introduced and that’s effects on main outputs (consumed power and surface roughness) was compared with other lubrication methods such as lubrication by cutting fluids and by air. In order to perform a series of experiments and investigate the effects of different process parameters such as tools rotational speed, feed rate, gas pressure and liquid flow rate on main outputs, the Taguchi method of design of experiments was employed and then the analysis of variance (ANOVA) was used to find the most important factors effecting main outputs. The results obtained by experiments showed that employing near dry lubrication leads to lower electrical power and comparable surface roughness as compared with other lubrication methods. The analysis of variance showed that feed rate is the most important factor affecting consumed power and liquid flow rate is the most important factor influencing surface roughness.
Mohammad Reza Shabgard, Behnam Karamzadeh, Reza Alizadegan, Ahad Gholipoor,
Volume 15, Issue 3 (5-2015)
Abstract

In this research the abrasive flow finishing process (AFF) of AISI H13 hot work steel was studied and the effects of various process parameters such as flow pressure (extrusion pressure), abrasive particles densities, abrasive particles sizes and the first quality of surfaces on variations of surface roughness and material removal have been investigated. The results showed that increasing the density of abrasive particles leads to increase in variations of surface roughness and material removal. Increase of extrusion pressure from 4 to 6 MPa causes the increase in variations of surface roughness and material removal and from 6 to 8 Mpa leads to decrease in the two latter. Electron microscopic results showed that increase of finishing process time over 4 hours causes a detrimental effect on the surface of the specimens, as a result of penetration and stabilization of abrasive particles in the form of broken particles. Also according the results of this paper, increasing the size of abrasive particles leads to higher variations of surface roughness and material removal, and this process is more effective in finishing of rougher surfaces.
Mohammad Reza Shabgard, Farzam Arabzadeh Tabriz, Ahad Gholipoor,
Volume 16, Issue 8 (10-2016)
Abstract

Abrasive flow machining (AFM) is a relatively new process with low material removal ratio for deburring, removing recast layers and finishing industrial components with complex shapes among non-conventional machining processes. In this process, the finishing is handled by flowing of the composition of viscoelastic and abrasive particles on workpiece surface, under the pressure of piston. In this research, the abrasive flow machining process of H13 tool steel with applied an external magnetic field around the workpiece for improve the material removal ratio and surface roughness has been investigated and the effect of magnetic field intensity, abrasive particles mesh and the hardness of workpiece as the input parameters on the process outputs including surface roughness and material removal ratio was studied. Also the regression model of MRR and surface roughness was developed and variance analysis was performed. Results of experiments indicated that increase in abrasive-particles mesh leads to decrease surface roughness and material remove ratio and increase in magnetic field intensity causes to increase material removal ratio and decrease surface roughness. Also the material removal ratio is decreased with increasing of workpiece hardness and on the same condition; better surface finish was achieved in the case of harder workpiece.
Mohammadreza Shabgard, Ahad Gholipoor,
Volume 17, Issue 12 (2-2018)
Abstract

Electric discharge machining is one of the most widely used non-traditional machining techniques which use thermal energy for machining in small dimensions, machining complex shapes and machining hard materials with high strength such as ceramics and heat-treated steels. In this study the ultrasonic vibrations and magnetic field assisted EDM process as a new hybrid process was introduced and used for machining of AISI H13 too steel, to solve the EDM process limitations such as low material removal rate. In this investigation, several experiments were designed and performed based on full factorial method by selecting pulse current and pulse duration as most effective parameters of EDM process in order to study the effects of applying ultrasonic vibrations to tool electrode and external magnetic field around gap distance of EDM process, simultaneously, on material removal rate and tool wear rate. According the results, applying ultrasonic vibrations to tool electrode and external magnetic field around gap distance of EDM process, simultaneously, despite the increases of tool wear rate, increases the material removal rate as compared with EDM (60%), ultrasonic vibrations assisted EDM (40%) and magnetic field assisted EDM processes (55%) in all pulse durations and pulse currents except in pulse current of 32 A. In pulse current of 32 A, because of the interference of the influences of applying ultrasonic vibrations to tool electrode and external magnetic field around gap distance, the material removal rate and tool wear ratio are decreased.
, Ali Asghar Amini Khasraghi, Ahad Gholipoor,
Volume 18, Issue 5 (9-2018)
Abstract

Rotational abrasive flow machining process (RAFM) is one of the modern surface polishing processes where in the material removal in micro and nano sizes is performed by tiny abrasive particles. Rotational abrasive flow machining is very effective in finishing of complex internal and external surfaces.in comparison with other finishing methods. In this study, the rotational abrasive flow machining process has been investigated in polishing of AISI H 13 hot work steel. The main objectives of workpiece rotation was increasing the material removal rate and decreasing the surface roughness of workpiece. So the effects of rotational speed and hardness of workpiece and the mesh size of abrasive particles as input variables on the output parameters including surface roughness and material removal rate have been studied. The results showed that applying of rotational speed of workpiece leads to higher material removal rate and lower surface roughness. Furthermore, the material removal rate is decreased and surface roughness is improved by increasing the mesh size of abrasive particles. Also, increasing the hardness of workpiece leads to decreasing the material removal rate, and in similar cutting conditions, the surface of workpiece with more hardness is better polished in comparison with the surface of workpiece with lower hardness.
, Ahad Gholipoor, Mousa Mohammadpourfard,
Volume 18, Issue 7 (11-2018)
Abstract

Despite the unique usage of electrical discharge machining process at machining in small dimensions, machining complex shapes and machining of high-strength parts such as ceramics and heat treated steels, which can’t be machined by traditional machining methods, low machined surface integrity achieved by electrical discharge machining process is one of the most important limitations of this process. In this investigation the machined surface integrity will be improved by applying ultrasonic vibrations to tool electrode and external magnetic field around gap distance of electrical discharge machining process, simultaneously. So several experiments were designed and performed based on full factorial method by selecting pulse current and pulse duration as the most important input parameters, in order to study the effects of pulse current and duration on surface integrity of workpiec machined by this hybrid process and to investigate the effects of tools ultrasonic vibrations and external magnetic field on machined surface roughness and integrity of machined surface. According the results, machined surfaces roughness is increased by applying ultrasonic vibrations to tool electrode and external magnetic field around gap distance of electrical discharge machining process, simultaneously, while the SEM pictures of machined surfaces showed that the, amount of created surface cracks, blowholes, globules and beads of debris are decreased and integrity of machined surfaces by EDM process is improved by applying ultrasonic vibrations to tool electrode and external magnetic field around gap distance, simultaneously.
M.r. Shabgard , A. Gholipoor , M. Mohammadpourfard ,
Volume 19, Issue 1 (January 2019)
Abstract

In this investigation, finite element method was used to model single discharge of ultrasonic vibrations and magnetic field assisted electrical discharge machining (MUEDM) process. Regarding good correlation between theoretical recast layer thickness obtained by process modeling and experimental recast layer thickness obtained by experiments with maximum error of 8.6%, the developed numerical model was used to find the temperature distribution at workpiece surface and predict the created craters dimensions on workpiece surface. The influences of applying ultrasonic vibrations to tool electrode simultaneous with applying external magnetic field around gap distance of electrical discharge machining (EDM) process, on plasma flushing efficiency, recast layer thickness and created craters dimensions were found by numerical and experimental analysis. The experimental and numerical results showed that applying magnetic field around gap distance and ultrasonic vibrations to tool electrode, simultaneously, at EDM process increases plasma flushing efficiency and decreases recast layer thickness. Also, applying magnetic field around gap distance and ultrasonic vibrations to tool electrode, simultaneously, at EDM process, leads to higher depth and volume of created craters on machined surface and lower craters radius.


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