Mohammad Vahid Ehteshamfar, Mohammad Sadegh Javadi and Hamed Adibi
Parts created with fused deposition modelling (FDM) have poor surface quality and dimensional accuracy, which limits their applicability in a variety of applications. Therefore…
Abstract
Purpose
Parts created with fused deposition modelling (FDM) have poor surface quality and dimensional accuracy, which limits their applicability in a variety of applications. Therefore, post process of FDM parts seems to be essential to tackle these problems. The purpose of this study is to study the influence of lapping parameters (time, weight and angular velocity) on the surface roughness, material removal rate (MRR) and flexural strength of acrylonitrile butadiene styrene (ABS) parts manufactured by FDM were post processed with the aid of lapping operation.
Design/methodology/approach
After printing the specimens, parts were lapped according to the Taguchi design of experiments. The surface roughness of the lapped parts was then evaluated by using laser profilometry, and the results were compared to study how lapping parameters affected surface roughness. A digital microscope was used to examine the surface damage of components that were being lapped. After that, the flexural strength of lapped parts was compared with the untreated part to study the effect of lapping process on the flexural strength. Finally, the influence of lapping parameters was investigated on the thickness change and MRR.
Findings
The results showed that while by increasing lapping time the surface roughness would improve; angular velocity and weight have an optimal value. The results also illustrated that not only the surface roughness of all ABS samples improve significantly but also the antistrophic behaviour of additively manufactured parts is turned to isotropic behaviour without decreasing flexural strength of specimens. MRR is also proportional to these parameters and by rising the value of them, MRR will increase.
Originality/value
The previous techniques of improving surface roughness whether chemical treatment or mechanical treatment had some disadvantages such as reducing mechanical properties, cost, long time of the process and so forth. As a result, finding a new approach such as lapping process to overcome the problems of previous methods seems to be necessary.
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Mohammad Javadi and Mehdi Sarkhosh
This study aims to investigate the perceptions of Iranian English teachers about their teaching efficiency through a specific practicum course, namely, language teaching…
Abstract
Purpose
This study aims to investigate the perceptions of Iranian English teachers about their teaching efficiency through a specific practicum course, namely, language teaching methodology. Drawing on a marketing education perspective, the researchers sought to measure the service quality offered in universities by examining teachers’ satisfaction with the curriculum.
Design/methodology/approach
Using quantitative gap analysis, the study evaluated the knowledge and skills of teachers in their preservice education regarding the perceived importance of knowledge and skills required in practice. The study involved 120 English as a foreign language teachers holding a BA degree from two universities in Iran, each with two to four years of teaching experience in the private sector. Data were collected using a 40-item semantic differential Likert scale developed by the researchers. The scale incorporated two components that assessed teachers’ perceived importance of knowledge and skills and their preservice educational preparation.
Findings
The findings revealed that most participants were overprepared in various items. However, there were some gaps in content knowledge and skills. Reasons for these gaps mainly included having adequate experience of and/or familiarity with course content, having completed relevant courses beforehand and imitating role model teachers. Teachers’ underpreparation was attributed to their lack of preparation in some specific subjects due to limited skill, practice, motivation, experience and familiarity with that content area.
Originality/value
This study explores the perceived knowledge and skills of Iranian English teachers and provides empirical insights into higher education service quality and customer satisfaction.
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Neda Hassanpour, Ali Shaemi Barzoki, Mohammad Hossein Moshref Javadi and Ali Safari
This study aimed at developing and testing a model to evaluate employee performance in Isfahan municipality.
Abstract
Purpose
This study aimed at developing and testing a model to evaluate employee performance in Isfahan municipality.
Design/methodology/approach
A mixed-method design is applied in this study. To extract the model, a semi-structured interview based on the thematic analysis approach was employed. The qualitative data were obtained using a researcher-made questionnaire from a sample of 12 municipal experts selected based on purposive sampling. In the quantitative phase, the sample consisted of 76 managers and interim managers. The validity of the questionnaire was determined by the content validity index, while the structural validity was tested based on structural equation modeling using SmartPLS software. The reliability of the questionnaire was confirmed using Cronbach's alpha and composite reliability indices.
Findings
The factors obtained in the qualitative model included performance evaluation criteria, the desired time interval for performance evaluation, results announcement, performance evaluation approach, performance evaluation method and evaluator-related variables. There should have been an agreement between evaluators and those who were evaluated in all components of the model. In the quantitative section, performance evaluation criteria, evaluators, the evaluation method and time interval were confirmed with coefficients of 0.871, 0.815, 0.646 and 0.615, respectively.
Practical implications
The novelty of this study is that it uses a mixed-method research approach to extract a performance evaluation model that is specific to the Isfahan municipality.
Originality/value
The novelty of this study is that it uses a mixed-method research approach to extract a performance evaluation model that is specific to the Isfahan municipality.
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Saeed Tavakkolimoghaddam, Seyyed Mohammad Hadji Molana, Mehrdad Javadi and Amir Azizi
By designing a system dynamics model in the form of a multimodal transportation system, this study for the first time seeks to reduce costs and time, and increase customer…
Abstract
Purpose
By designing a system dynamics model in the form of a multimodal transportation system, this study for the first time seeks to reduce costs and time, and increase customer satisfaction by considering uncertainties in the intra city transit system, especially demand uncertainty and provide a prototype system to prove the capability of the dynamical system.
Design/methodology/approach
The paper tried to model the factors affecting the intra city multimodal transportation system by defining different scenarios in the cause-and-effect model. The maps and results developed according to system dynamics modeling principles are discussed.
Findings
Four scenarios were considered given the factors affecting the urban transportation system to implement the transportation information system for reducing the material and non-material costs of wrong planning of the intra city transit system. After implementing the scenarios, scenario two was selected under the following conditions: advertising for cultural development, support of authorities by efforts such as street widening to reduce traffic, optimize infrastructure, increase and optimize public transport and etc.
Originality/value
The value of this paper is considering uncertainty in traffic optimization; taking into account behavioral and demand indicators such as cultural promotion, official support, early childhood learning, traffic hours and the impact of traveler social status; investigating the factors affecting the system under investigation and the reciprocal effects of these factors and real-world simulation by considering the factors and effects between them.