Search results

1 – 10 of 12
Article
Publication date: 15 February 2024

Ali Hashemi, Hamed Taheri and Mohammad Dehghani

To prevent the coil from burning or getting damaged, it is necessary to estimate the duration of its operation as long as its temperature does not exceed the permissible limit…

Abstract

Purpose

To prevent the coil from burning or getting damaged, it is necessary to estimate the duration of its operation as long as its temperature does not exceed the permissible limit. This paper aims to investigate the effect of switching on the thermal behavior of impregnated and nonimpregnated windings. Also, the safe operating time for each winding is determined.

Design/methodology/approach

The power loss of the winding is expressed as a function of the winding specifications. Using homogenization techniques, the equivalent thermal properties for the homogenized winding are calculated and used in a proposed thermal equivalent circuit for winding modeling and analysis. The validity and accuracy of the proposed model are determined by comparing its analysis results and simulation and measurement results.

Findings

The results show that copper windings have better thermal behavior and lower temperature compared to aluminum windings. On the other hand, by impregnating or increasing the packing factor of the winding, the thermal behavior is improved. Also, by choosing the right duty cycle for the winding current source, it is possible to prevent the burning or damage of the winding and increase its lifespan. Comparing the measurement results with the analysis results shows that the proposed equivalent circuit has an error of less than 4% in the calculation of the winding center temperature.

Research limitations/implications

In this paper, the effect of temperature on the electrical resistance of the coil is ignored. Also, rectangular wires were not investigated. Research in these topics are considered as future work.

Originality/value

By calculating the thermal time constant of the winding, its safe operation time can be calculated so that its temperature does not exceed the tolerable value (150 °C). The proposed method analyzes both impregnated and nonimpregnated windings with various schemes. It investigates the effects of switching on their thermal behavior. Additionally, it determines the safe operating time for each type of winding.

Details

World Journal of Engineering, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 14 August 2021

Hamed Fasihi Pour Parizi, Saeed Seyedtabaii and Mahdi Akhbari

The purpose of this study is to develop an algorithm to accurately detect faults in series capacitor compensated (SCC) power transmission lines. The line fault must be…

Abstract

Purpose

The purpose of this study is to develop an algorithm to accurately detect faults in series capacitor compensated (SCC) power transmission lines. The line fault must be distinguished from stable power swing, compensating unit malfunction and defects on other lines sharing the same bus (external faults).

Design/methodology/approach

In this regard, an effective fault feature extractor based on the cumulative sum (CUSUM) of the amplified second harmonic of the phase currents is suggested. The features are then applied to an artificial neural network for classification. No-fault cases include stable power swing and several disturbances. Due to the independent analysis of each phase, faulty phase detection is also a by-product.

Findings

Various fault scenarios are defined, and the algorithm success rate is compared with some newly published methods. Extensive simulations performed over a single-machine infinite bus, a 3-machine, 9-bus and the large-scale New England IEEE 39-Bus networks all indicate that the proposed algorithm can trip the faulty line more quickly and accurately than the contestant algorithms.

Originality/value

Suggestion of a new algorithm based on the CUSUM of the amplified second harmonic of the phase current for the fault feature extraction that is able to isolate the transmission line internal faults from stable poser swing, line compensating unit malfunction and faults on the adjacent lines connected to the same bus.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 40 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 18 January 2024

Shiba Hessami, Hamed Davari-Ardakani, Youness Javid and Mariam Ameli

This study aims to deal with the multi-mode resource-constrained project scheduling problem (MRCPSP) with the ability to transport resources among multiple sites, aiming to…

Abstract

Purpose

This study aims to deal with the multi-mode resource-constrained project scheduling problem (MRCPSP) with the ability to transport resources among multiple sites, aiming to minimize the total completion time and the total cost of the project simultaneously.

Design/methodology/approach

To deal with the problem under consideration, a bi-objective optimization model is developed. All activities are interconnected by finish-start precedence relations, and pre-emption is not allowed. Then, the ɛ-constraint optimization method is used to solve 24 different-sized instances, ranging from 5 to 120 activities, and report the makespan, total cost and CPU time. A set of Pareto-optimal solutions are determined for some instances, and sensitivity analyses are performed to find the impact of changing parameters on objective values.

Findings

Results highlight the importance of resource transportability assumption on project completion time and cost, providing useful insights for decision makers and practitioners.

Originality/value

A novel bi-objective optimization model is proposed to deal with the multi-site MRCPSP, considering both the cost and time of resource transportation between multiple sites. To the best of the authors’ knowledge, none of the studies in the project scheduling area has yet addressed this problem.

Article
Publication date: 12 March 2021

Hamed Dabaghi, Saeid Saieda Ardakani and Seyed Mohammad Tabataba’i-Nasab

The purpose of this paper is to focus on the emerging phenomenon of medical tourism in the context of Iran from a customer experience management perspective and benchmark of their…

Abstract

Purpose

The purpose of this paper is to focus on the emerging phenomenon of medical tourism in the context of Iran from a customer experience management perspective and benchmark of their judgment including positive or negative, of the experience they have achieved of the Iranian health (medical) experience (CE) and suggest scenarios for the improvement of the Iranian customer experience management (CEM).

Design/methodology/approach

The research methodologies and research methods that are used in this descriptive-analytical research are based on an inspection of the remarkable literature related to medical tourism and customer experience management. The data gathering instrument is a researcher-made questionnaire based on the variables in the conceptual model extracted from the research literature. The study was conducted from May to August 2019. The population cohort of this study was the foreign patients calling selected Iranian hospitals and the sampling method was a purposive and snowball sample of prospective medical tourists. As the study was conducted throughout Iran, some important hospitals in Iran were selected by stratified sampling Yang et al. (2020b). The sample size and data saturation were 500 participants Lv and Song (2019). The collected data using the questionnaire were analyzed by SPSS software and statistical tests.

Findings

According to the results, the customer experience management statistical significance in the task aspect is (p = 0.0523), in the mechanical aspect is (p = 0.0563), in the human aspect is (p = 0.0544). The study showed positive customer experience among the patients who had been treated in the Iranian hospitals.

Originality/value

There is a lack of study that focuses on medical tourism and customer experience management in Iran. Therefore, based on the results of this study, the experience of medical tourists in Iran proved to be positive and satisfying. As little research has been conducted in the area of customer experience management (CEM) in Iranian medical tourism, future researchers can use these valuable results precisely and in more detail to benchmark more accurately the customer experience in all areas of medical and health tourism and other research areas in different aspects of CEM in Iran.

Details

Journal of Islamic Marketing, vol. 13 no. 1
Type: Research Article
ISSN: 1759-0833

Keywords

Book part
Publication date: 6 September 2019

Abstract

Details

Experiencing Persian Heritage
Type: Book
ISBN: 978-1-78754-813-8

Abstract

Details

Experiencing Persian Heritage
Type: Book
ISBN: 978-1-78754-813-8

Article
Publication date: 7 April 2023

Erhan Boğan, Caner Çalışkan, Osman M. Karatepe and Hamed Rezapouraghdam

The purpose of this paper is to explore the selected antecedents (i.e. supervisor support and organizational justice) and outcomes (i.e. voice behavior and career satisfaction) of…

Abstract

Purpose

The purpose of this paper is to explore the selected antecedents (i.e. supervisor support and organizational justice) and outcomes (i.e. voice behavior and career satisfaction) of work engagement (WENG).

Design/methodology/approach

To gauge the aforesaid effects via structural equation modeling, the current study used data collected from hospitality and tourism academicians at public universities in Turkey.

Findings

The proposed model is viable. Specifically, WENG mediates the impacts of supervisor support and organizational justice on voice behavior and career satisfaction.

Research limitations/implications

Using longitudinal data in future research would make it possible to draw causal inferences. Testing research productivity as a criterion variable in future papers would enable the researchers to ferret about whether WENG would mediate the effects of supervisor support and organizational justice on research productivity.

Originality/value

Evidence about the factors affecting employees' WENG is still meager. Especially, there is a need for research about the factors that may affect academicians' WENG at universities. Research findings present valuable implications for tourism and hospitality educational institutions.

Details

Journal of Hospitality and Tourism Insights, vol. 7 no. 1
Type: Research Article
ISSN: 2514-9792

Keywords

Article
Publication date: 7 September 2015

Rachid Halfaoui and Bachir Chemani

The purpose of this paper is to conduct a series of tests designed to highlight changes in the physical characteristics of the yarn resulting from mechanical efforts comparable to…

Abstract

Purpose

The purpose of this paper is to conduct a series of tests designed to highlight changes in the physical characteristics of the yarn resulting from mechanical efforts comparable to that to which they are subjected on the weaving machine. Among the physical properties of the warp yarn, the authors examined changes include: the residual deformation, strength, elongation and elasticity, on the extender repetition effort overtension growing steadily, leading, after some time, to break. Therefore, the yarn treated extender repetition is subject to a more severe test than the actual weaving on the loom.

Design/methodology/approach

The initial length of the specimen under constant static load of 20 g, was 50 cm in all tests. The yarns are stored on several coils, the authors collected a quantity of thread on each of them, according to the law of chance, to avoid errors due to long periods of irregularity and the authors estimated that the extensions can be supported by the wire without danger of rupture are interesting practical point of view. Three rate extensions were chosen for the two yarns: 0.5, 1.2 and 1.9 percent. The maximum number of tractions was calculated for each wire by multiplying the maximum thread count practice by the average distance between the warp beam and the weft yarn on the weaving machine.

Findings

The fall of the resistance and elongation resulting from repeated extensions which yarn are subjected on the extensometer, corresponds almost exactly to the residual deformation recorded. Increasing the rate of extensions causes relatively large decrease in strength and elongation. The authors also notice that the strength and elongation at break tends to decrease when the number of extensions decreases. The fall of the resistance and the elongation at break is more important for carded yarns then combed yarns increases or when the frequency decreases.

Originality/value

The maximum difference of the resistance is 32 g, 10.3 percent in the case of carded yarns, while in the case of the combed yarns; the same difference is 25 g, or 6.4 percent of the initial strength. Similarly, the maximum fall of the elongation at break for carded yarns is about 2 or 16.1 percent of the initial elongation, while the corresponding drop in the case of the combed yarns is 1.8 or 10.9 percent of the initial elongation. The corresponding values found during the testing wool combed yarns, were, respectively about 4.8 and 6.6 percent.

Details

International Journal of Clothing Science and Technology, vol. 27 no. 5
Type: Research Article
ISSN: 0955-6222

Keywords

Article
Publication date: 23 June 2015

Hamed Fazlollahtabar, Mohammad Saidi-Mehrabad and Ellips Masehian

This paper aims to propose and formulate a complicated routing/scheduling problem for multiple automated guided vehicles (AGVs) in a manufacturing system.

1059

Abstract

Purpose

This paper aims to propose and formulate a complicated routing/scheduling problem for multiple automated guided vehicles (AGVs) in a manufacturing system.

Design/methodology/approach

Considering the due date of AGVs requiring for material handling among shops in a jobshop layout, their earliness and tardiness are significant in satisfying the expected cycle time and from an economic view point. Therefore, the authors propose a mathematical program to minimize the penalized earliness and tardiness for a conflict-free and just-in-time production.

Findings

The model considers a new concept of turning point for deadlock resolution. As the mathematical program is difficult to solve with a conventional method, an optimization method in two stages, namely, searching the solution space and finding optimal solutions are proposed. The performance of the proposed mathematical model is tested in a numerical example.

Practical implications

A case study in real industrial environment is conducted. The findings lead the decision-makers to develop a user interface decision support as a simulator to plan the AGVs’ movement through the manufacturing network and help AGVs to prevent deadlock trap or conflicts. The proposed decision support can easily be commercialized.

Originality/value

The benefits of such commercialization are increase in the quality of material handling, improve the delivery time and prevent delays, decrease the cost of traditional handling, capability of computerized planning and control, intelligent tracking and validation experiments in simulation environment.

Details

Industrial Robot: An International Journal, vol. 42 no. 3
Type: Research Article
ISSN: 0143-991X

Keywords

Open Access
Article
Publication date: 21 April 2023

Rana I. Mahmood, Harraa S. Mohammed-Salih, Ata’a Ghazi, Hikmat J. Abdulbaqi and Jameel R. Al-Obaidi

In the developing field of nano-materials synthesis, copper oxide nanoparticles (NPs) are deemed to be one of the most significant transition metal oxides because of their…

1001

Abstract

Purpose

In the developing field of nano-materials synthesis, copper oxide nanoparticles (NPs) are deemed to be one of the most significant transition metal oxides because of their intriguing characteristics. Its synthesis employing green chemistry principles has become a key source for next-generation antibiotics attributed to its features such as environmental friendliness, ease of use and affordability. Because they are more environmentally benign, plants have been employed to create metallic NPs. These plant extracts serve as capping, stabilising or hydrolytic agents and enable a regulated synthesis as well.

Design/methodology/approach

Organic chemical solvents are harmful and entail intense conditions during nanoparticle synthesis. The copper oxide NPs (CuO-NPs) synthesised by employing the green chemistry principle showed potential antitumor properties. Green synthesised CuO-NPs are regarded to be a strong contender for applications in the pharmacological, biomedical and environmental fields.

Findings

The aim of this study is to evaluate the anticancer potential of CuO-NPs plant extracts to isolate and characterise the active anticancer principles as well as to yield more effective, affordable, and safer cancer therapies.

Originality/value

This review article highlights the copper oxide nanoparticle's biomedical applications such as anticancer, antimicrobial, dental and drug delivery properties, future research perspectives and direction are also discussed.

Details

Arab Gulf Journal of Scientific Research, vol. 42 no. 2
Type: Research Article
ISSN: 1985-9899

Keywords

1 – 10 of 12