Arash Kiyoumarsi, Abolfazl Nazari, Mohammad Ataei, Hamid Khademhosseini Beheshti and Rahmat‐Allah Hooshmand
The purpose of this paper is to present a 3D finite element model of the electromagnetic fields in an AC three‐phase electric arc furnace (EAF). The model includes the electrodes…
Abstract
Purpose
The purpose of this paper is to present a 3D finite element model of the electromagnetic fields in an AC three‐phase electric arc furnace (EAF). The model includes the electrodes, arcs, and molten bath.
Design/methodology/approach
The electromagnetic field in terms of time in AC arc is also modeled, utilizing a 3D finite element method (3D FEM). The arc is supposed to be an electro‐thermal unit with electrical power as input and thermal power as output. The average Joule power, calculated during the transient electromagnetic analysis of the AC arc furnace, can be used as a thermal source for the thermal analysis of the inner part of furnace. Then, by attention to different mechanisms of heat transfer in the furnace (convection and radiation from arc to bath, radiation from arc to the inner part of furnace and radiation from the bath to the sidewall and roof panel of the furnace), the temperature distribution in different parts of the furnace is calculated. The thermal model consists of the roof and sidewall panels, electrodes, bath, refractory, and arc. The thermal problem is solved in the steady state for the furnace without slag and with different depths of slag.
Findings
Current density, voltage and magnetic field intensity in the arcs, molten bath and electrodes are predicted as a result of applying the three‐phase AC voltages to the EAF. The temperature distribution in different parts of the furnace is also evaluated as a result of the electromagnetic field analysis.
Research limitations/implications
This paper considers an ideal condition for the AC arc. Non‐linearity of the arc during the melting, which leads to power quality disturbances, is not considered. In most prior researches on the electrical arc furnace, a non‐linear circuit model is usually used for calculation of power quality phenomena distributions. In this paper, the FEM is used instead of non‐linear circuits, and calculated voltage and current densities in the linear arc model. The FEM results directly depend on the physical properties considered for the arc.
Originality/value
Steady‐state arc shapes, based on the Bowman model, are used to calculate and evaluate the geometry of the arc in a real and practical three‐phase AC arc furnace. A new approach to modeling AC arcs is developed, assuming that the instantaneous geometry of the AC arc at any time is constant and is similar to the geometry of a DC arc with the root mean square value of the current waveform of the AC arc. A time‐stepping 3D FEM is utilized to calculate the electromagnetic field in the AC arc as a function of time.
Details
Keywords
Seyed Hadi Hoseinie, Mohammad Ataei, Reza Khalokakaie, Behzad Ghodrati and Uday Kumar
Longwall mining is a special mining method with high productivity and smooth operation and the drum shearer is known as the most important component in longwall mines due to its…
Abstract
Purpose
Longwall mining is a special mining method with high productivity and smooth operation and the drum shearer is known as the most important component in longwall mines due to its direct role in the coal cutting and production process. Therefore, its reliability is important in keeping the mine production at a desired level. Hence, reliability analysis is essential in identifying and removing existing problems of this machine in order to achieve a better production condition. This paper seeks to learn about the reliability of the shearer machine in order to locate critical subsystems. The improvement of the reliability of the critical subsystems, to enhance the optimum operation of the shearer machine, is the main objective of this research.
Design/methodology/approach
A basic methodology was used in this paper for the reliability modeling of the shearer machine. First, failure and performance data from a two‐year period at the Tabas Coal Mine‐Iran was classified and sorted. The tests for validating the assumption of independent and identical distribution (iid) of TBF data are done and the best modeling method for each subsystem was selected among the renewal process, homogeneous Poisson process and non‐homogeneous Poisson process. Finally, the reliability of subsystems and the machine were assessed.
Findings
The study revealed that six important subsystems of the shearer machine are; water system, haulage, electrical system, hydraulic system, cutting arms, and cable system. Pareto analysis shows that the 30 percent of failures and stoppages of the shearer were related to the water system and this system is the most critical subsystem of the machine. The failure rate analysis shows that the failure rates of the hydraulic, haulage and electrical systems were decreasing, meanwhile, the failure rates of the water system, cutting arms and cable system were increasing. The reliability of drum shearer reaches the zero value after 100 hours.
Originality/value
This paper, for the first time, defines a practical set of subsystems for the coal shearer based on field data and machine design.
Details
Keywords
Junior Polo Salinas, Jairo Jhonatan Marquina Araujo and Marco Antonio Cotrina Teatino
This study aims to provide a comprehensive review of the existing literature on uncertainty in underground mining operations, using a bibliometric and systematic analysis covering…
Abstract
Purpose
This study aims to provide a comprehensive review of the existing literature on uncertainty in underground mining operations, using a bibliometric and systematic analysis covering the period from 1975 to 2024.
Design/methodology/approach
To achieve this, the following questions were addressed using a mixed-method approach involving bibliometrics, text mining and content analysis: How has the field of uncertainty research in underground mining operations evolved? What are the most prominent research topics and trends in uncertainty in underground mining operations? and What are the possible directions for future research on uncertainty in underground mining operations?
Findings
As a result, bibliometric networks of 327 journal articles from the Scopus database were created and examined, the main research topics were underground mining management; rock mechanics; operational optimization; and stochastic systems. Finally, the inclusive investigation of uncertainty in underground mining operations and its prominent patterns can serve as a basis for real-time direction for new research and as a tool to improve underground mining activities by implementing advanced technology for innovative practices and optimizing operational efficiency. This is fundamental to identify unknown variables that impair the planning, operation, safety and economic viability of underground mines.
Originality/value
This research is 100% original because there is no review research on the uncertainty present in underground mining operations.
Details
Keywords
Ghobad Moradi, Amjad Mohamadi-Bolbanabad, Sonia Darvishi, Fatemeh Azimian Zavareh, Bakhtiar Piroozi, Bushra Zareie, Mohammad-Mehdi Gouya and Mehrzad Tashakorian
The purpose of this paper is to determine patterns of sexual behaviors and related factors among prisoners in Iran, 2015.
Abstract
Purpose
The purpose of this paper is to determine patterns of sexual behaviors and related factors among prisoners in Iran, 2015.
Design/methodology/approach
This cross-sectional study was a part of a bio-behavioral surveillance survey conducted on 6,200 prisoners in 26 prisons in Iran. The subjects were selected through multi-stage sampling. Questionnaires and interviews were used to collect data on participant’s demographics and history of sexual behaviors. Using STATA-12 software, the collected data were analyzed through descriptive statistics, and crude and adjusted logistic regression.
Findings
A total of 5,508 prisoners with a response rate of 88.8 percent participated in this study. Of all prisoners, 55 percent (n=3,027) had a history of “unsafe sex in the lifetime” of whom 53.4 percent (n=1,549) never used condoms during unsafe sex in the lifetime. Based on the results of multivariate analysis, risk factors for “unsafe sex in lifetime” were the following: higher level of education (AOR=1.79, CI: 1.41–2.28), being single (AOR=1.32, CI: 1.18–1.47), unemployed before imprisonment (AOR=1.45, CI: 1.06–1.97), having history of previous imprisonment (AOR=1.31, CI: 1.17–1.47) and history of drug use in the lifetime (AOR=1.53, CI: 1.35–1.75).
Originality/value
Prisoners are high-risk groups that are prone to practice unsafe sex. Prisoners who are single, unemployed before imprisonment, a drug user, with a higher level of education and with a history of imprisonment are likely to be sexually active in their lifetime. Thus, they are a priority for receiving suitable interventions.
Details
Keywords
Mohammad Sadegh Sharifirad and Vahid Ataei
The purpose of this paper is to examine the influence of organizational culture (OC) on the building blocks of innovation culture (IC) in Iranian auto companies.
Abstract
Purpose
The purpose of this paper is to examine the influence of organizational culture (OC) on the building blocks of innovation culture (IC) in Iranian auto companies.
Design/methodology
In total, a sample of six large auto companies were examined and 245 questionnaires completed by employees. A conceptual model was developed and the hypotheses analyzed by using exploratory factor analysis and then the direct and indirect effects of constructs were analyzed by path analysis technique.
Findings
Findings suggest that the constructs of OC correlate with those of IC. These correlations are all positive except for the relations between consistency and organizational learning, as well as of that between consistency and creativity and improvement.
Practical implications
First, this paper has checked the validity of both questionnaires in an Iranian context so that they could be used with more confidence. Second, innovation can flow in the organizations when organizational culture supports it. This research specified those elements which can help managers and executives find the aspects of OC which can increase IC.
Originality/value
The paper serves as a reference for fostering an IC in auto companies. Paying attention to different aspects of OC can have a positive effect on making innovation pervasive in organizations. This research was done for the first time in an Asian context and is literally unprecedented in Iran.
Details
Keywords
Mohammed Awad Alshahrani, Muhammad Zafar Yaqub, Murad Ali, Imane El Hakimi and Mohammad Asif Salam
Building on social cognitive theory and self-determination theory, this study aims to discern the innovative work behaviors of organizational employees as the process by which…
Abstract
Purpose
Building on social cognitive theory and self-determination theory, this study aims to discern the innovative work behaviors of organizational employees as the process by which they generate, develop and implement new and valuable ideas, practices, products or procedures shaped by entrepreneurial leadership by reinforcing intrinsic motivation and creative self-efficacy under the boundary condition of a firm’s innovative climate.
Design/methodology/approach
This study used partial least squares-based structural equation modeling on a sample of 203 employees of small and medium-sized enterprises operating in Saudi Arabia.
Findings
This study found that entrepreneurial leadership improves employees’ innovative work behavior by successively enhancing their intrinsic motivation and creative self-efficacy. Furthermore, the analysis confirmed that a firm’s innovative climate significantly moderates the strength of the indirect mediation effect between entrepreneurial leadership and employees’ innovative work behavior through sequential mediation.
Practical implications
The findings of this study yield substantial theoretical and practical implications resulting from a fine-grained understanding of the instrumentality of entrepreneurial leadership in fostering employees’ innovative work behavior. Effectively orchestrating these psychological mechanisms could enable entrepreneurial leaders to alleviate their behaviors.
Originality/value
This is an original study that outlines the importance of aligning entrepreneurial leadership and an innovative climate to shape intrinsic motivation and creative self-efficacy in employees’ innovative work behavior. It demonstrates how entrepreneurial leadership enhances innovative work behavior through the sequential mediation of intrinsic motivation and creative self-efficacy under the boundary condition of an innovative climate.
Details
Keywords
Mohammad Majid Fouladgar, Ahmad Borumand Kakhki, Alireza Nasr Esfehani and Mohammadsadegh Sedighi
This paper aims to propose a policy prioritization framework in view of a layered scenario building along with key stakeholder analysis and has been applied in a case study to…
Abstract
Purpose
This paper aims to propose a policy prioritization framework in view of a layered scenario building along with key stakeholder analysis and has been applied in a case study to determine the priority of Iran environmental policies at the horizon of 2030. A creative framework that covers future scenarios and allows for a more accurate and intelligent policy assessment and prioritization.
Design/methodology/approach
The general environmental policies of the Islamic Republic of Iran are evaluated, and observation policies in social area were identified. Causal layered analysis (CLA) is applied for policy prioritization based on layered probable scenarios and key stakeholder role consideration. The Multiple-criteria decision-making (MCDM) is also used for ranking General Environmental Policies by the technique for order of preference by similarity to ideal solution (TOPSIS).
Findings
Four uncertainties were obtained in different layers based on the CLA analysis, resulting in the creation of four main scenario and 16 discrete scenarios. Finally, Iran’s environmental policies were prioritized given the probable scenarios and the centralized policies on the social and political domains. The proposed model will be effective in policy-making in multilateral atmosphere to prioritize policies and alternative macro-strategies.
Originality/value
This paper shows that foresight and especially developed scenarios provide intelligent, efficient and effective planning and policy-making, and in addition to illustrating surrounding changes and probable future imagery, it generates common understanding and inter-subjective knowledge by increasing participation of various officials and stakeholders.
Details
Keywords
The purpose of this paper is to examine the direct role being played by transformational leadership (TL) dimensions in reinforcing product and service innovation. More…
Abstract
Purpose
The purpose of this paper is to examine the direct role being played by transformational leadership (TL) dimensions in reinforcing product and service innovation. More particularly, the paper focusses on the role of job satisfaction (JS) as a mediator in this relationship.
Design/methodology/approach
A concurrent mixed methods technique was employed. The researcher surveyed 486 participants from three major telecoms companies that operate in Jordan to supply the society with mobile phones and internet services. In addition, 15 team leaders were interviewed for the same purpose.
Findings
The results of this paper support the positive direct impact of transformational leaders on both employees’ innovativeness and JS. In addition, JS was found to positively impact product and service innovation. Moreover, the results revealed that JS mediates the relationship between TL and innovation.
Research limitations/implications
Leaders are playing a direct and significant role in reinforcing product and service innovation in an interesting manner, especially through JS. Other styles of leadership, populations, and methods may create new perceptions in further research works.
Practical implications
The findings in this paper indicate that practising superior level of TL behaviours enhances overall JS, which, as a result, reinforces product and service innovation within employees in the Jordanian telecom sector. Superior outputs are achieved through such styles both for the firm as a whole towards innovative products and services, and similarly, for individuals within teams who involve in further innovative team climate.
Originality/value
These outcomes augment understanding of practises in which transformational leaders endorse innovation, and emphasise the values added through endorsing more TL behaviours to yield more innovative outputs by employees.
Details
Keywords
Alireza Rousta and Elnaz Allaf Jafari
The constant population growth and inappropriate consumption patterns have led to abnormal use of the earth's capacities, destruction of natural resources, enormous spread of…
Abstract
Purpose
The constant population growth and inappropriate consumption patterns have led to abnormal use of the earth's capacities, destruction of natural resources, enormous spread of diseases, and increased waste materials. Thus, these issues should be highlighted to avoid serious problems for the earth. Accordingly, this study examines the effect of environmental knowledge (EK), environmental responsibility (ER), and environmental concern (EC) on sustainable consumption behavior (SCB), with the mediating role of customer attitude (CA).
Design/methodology/approach
The present applied study is descriptive-correlational. The statistical population includes customers of Hyperstar stores located in Tehran. Overall, a sample size of 384 people was selected based on Cochran's formula. The data were collected using standard questionnaires and analyzed using structural equation modeling and Smart PLS version 3 software.
Findings
The fit of the proposed model was confirmed at measurement, structural, and general levels. Thus, it indicates that the structural model has an acceptable fit. Furthermore, the findings emphasize that ER and EC have a positive effect on CA, and ER and EC have a positive impact on SCB. ER and EC have a positive effect on SCB through the mediation of CA, while EK does not have any significant effect on SCB but EK has an effect on SCB through the mediation of CA.
Originality/value
Given the growth of environmental destruction, it is necessary to consider the change of CA toward buying sustainable products. Therefore, this study pays attention to the mediating role of attitude and examines the effects of EK, EC, and ER that cause SCB among customers of Hyperstars.
Details
Keywords
Hoa Pham, Huu Phuc Dang and Bang Nguyen-Viet
The call for consumption reduction behavior has been getting more attention from scholars and practitioners. However, the consumption reduction often receives backfire from…
Abstract
Purpose
The call for consumption reduction behavior has been getting more attention from scholars and practitioners. However, the consumption reduction often receives backfire from consumers because it does not follow the business philosophy of demand creation. Thus, this research dissolves this issue by using a holistic corporate social responsibility (CSR) approach regarding sustainable development.
Design/methodology/approach
A conceptual model was developed to represent the proposed relationships among the related variables. The current study employed an online survey to collect data from 341 international program students of three prominent universities in Ho Chi Minh City, Vietnam.
Findings
The findings indicate that the perception of the holistic CSR negatively impacts perceived corporate hypocrisy, triggering in turn brand credibility, resulting in brand advocacy and mindful consumption behavior.
Originality/value
This research forms a holistic CSR including economic, environmental and societal dimensions and proposes that the holistic CSR triggers brand advocacy and mindful consumption behavior representing consumption reduction behavior via the mediating roles of perceived corporate hypocrisy and brand credibility. These findings contribute to theoretical and managerial implications in CSR practices with the aim of consumption reduction.