Masoud Nosrati and Ronak Karimi
This paper aims to provide a method for media resource allocation in Cloud systems for supporting green computing policies, as well as attempting to improve the overall…
Abstract
Purpose
This paper aims to provide a method for media resource allocation in Cloud systems for supporting green computing policies, as well as attempting to improve the overall performance of system by optimizing the communication latencies.
Design/methodology/approach
A common method for resource allocation is using resource agent that takes the budgets/prices of applicants/resources and creates a probability matrix of allocation according to the policies of system. Two general policies for optimization are latency optimization and green computing. Presented heuristic for latencies is so that the average latencies of communication between applicant and resource are measured, and they will affect the next decision. For gaining green computing, it is attempted to consolidate the allocated resources on smaller number of physical machines. So calculation formula of the price of each resource is modified to decrease the probability of allocating the resources on the machine with least allocated resources.
Findings
Results of proposed method indicates its success in both green computing and improving the performance. Experiments show decreasing 21.4 per cent of response time simultaneously with increasing tasks in the tested range. The maximum and minimum of saved energy is acceptable and reported as 79.2 and 16.8 per cent.
Research limitations/implications
Like other centralized solutions, the proposed method suffers from the limitations of centralized resource agent, like bottle neck. But the implementation of distributed resource agent is postponed to future work.
Originality/value
Proposed method presents heuristics for improving the performance and gaining green computing. The key feature is formulating all the details and considering pitch variables for controlling the policies of system.
Details
Keywords
Yeping Peng, Ghasem Bahrami, Hossein Khodadadi, Alireza Karimi, Ahmad Soleimani, Arash Karimipour and Sara Rostami
The purpose of this study is simulation of of polymer electrolyte membrane fuel cell. Proton-exchange membrane fuel cells are promising power sources for use in power plants and…
Abstract
Purpose
The purpose of this study is simulation of of polymer electrolyte membrane fuel cell. Proton-exchange membrane fuel cells are promising power sources for use in power plants and vehicles. These fuel cells provide a high level of energy efficiency at low temperature without any pollution. The convection inside the cell plays a key role in the electrochemical reactions and the performance of the cell. Accordingly, the transport processes in these cells have been investigated thoroughly in previous studies that also carried out functional modeling.
Design/methodology/approach
A multi-phase model was used to study the limitations of the reactions and their impact on the performance of the cell. The governing equations (conservation of mass, momentum and particle transport) were solved by computational fluid dynamics (CFD) (ANSYS fluent) using appropriate source terms. The two-phase flow in the fuel cell was simulated three-dimensionally under steady-state conditions. The flow of water inside the cell was also simulated at high-current density.
Findings
The simulation results suggested that the porosity of the gas diffusion layer (GDL) is one of the most important design parameters with a significant impact on the current density limitation and, consequently, on the cell performance.
Originality/value
This study was mainly focused on the two-phase analysis of the steady flow in the fuel cell and on investigating the impacts of a two-phase flow on the performance of the cell and also on the flow in the GDL, the membrane and the catalyst layer using the CFD.
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Mohammad Reza Salimpour, Mohammad Hossein Karimi Darvanjooghi, Ali Abdollahi, Arash Karimipour and Marjan Goodarzi
A boiling surface with different initial roughness and under various nanoparticles volume fractions was studied in present work.
Abstract
Purpose
A boiling surface with different initial roughness and under various nanoparticles volume fractions was studied in present work.
Design/methodology/approach
Develop a correlation and sensitivity analysis.
Findings
The results showed that for small (7.3 nm) and much larger (about 2,000 nm) surface roughness, compared to nanoparticle size of around 25 nm, the heat transfer rate of nanofluid diminishes relative to that of base fluid. The results also demonstrated that the boiling heat transfer rate is reduced by increasing the concentration of nanoparticles. For larger boiling surface roughness (480 nm) and nanoparticles volume fractions of less than 0.1 Vol.%, the value of heat transfer increases with the increase of nanoparticles concentration; and for those of more than 0.1 Vol.%, heat transfer rate decreases by adding more nanoparticles, significantly.
Originality/value
Finally, an equation was presented for estimating the wall superheat and the Csf coefficient in terms of mentioned parameters.
Details
Keywords
Davood Afshari, M. Sedighi, M.R. Karimi and Z. Barsoum
The purpose of this paper is to predict residual stresses in resistance spot weld of 2 mm thick aluminum 6061-T6 sheets. The joint use of finite element analysis and artificial…
Abstract
Purpose
The purpose of this paper is to predict residual stresses in resistance spot weld of 2 mm thick aluminum 6061-T6 sheets. The joint use of finite element analysis and artificial neural networks can eliminate the high costs of residual stresses measuring tests and significantly shorten the time it takes to arrive at a solution.
Design/methodology/approach
Finite element method and artificial neural network have been used to predict the residual stresses. Different spot welding parameters such as the welding current, the welding time and the electrode force have been used for the simulation purposes in a thermal-electrical-structural coupled finite element model. To validate the numerical results, a series of experiments have been performed, and residual stresses have been measured. The results obtained from the finite element analysis have been used to build up a back-propagation artificial neural network model for residual stresses prediction.
Findings
The results revealed that the neural network model created in this study can accurately predict residual stresses produced in resistance spot weld. Using a combination of these two developed models, the residual stresses can be predicted in terms of spot weld parameters with high speed and accuracy.
Practical implications
The paper includes implication for aircraft and automobile industries to predict residual stresses. Residual stresses can lower the strength and fatigue life of the spot-welded joints and determine the performance quality of the structure.
Originality/value
This paper presents an approach to reduce the high costs and long times of residual stresses measuring tests.
Details
Keywords
Masoud Nosrati and Mahmood Fazlali
One of the techniques for improving the performance of distributed systems is data replication, wherein new replicas are created to provide more accessibility, fault tolerance and…
Abstract
Purpose
One of the techniques for improving the performance of distributed systems is data replication, wherein new replicas are created to provide more accessibility, fault tolerance and lower access cost of the data. In this paper, the authors propose a community-based solution for the management of data replication, based on the graph model of communication latency between computing and storage nodes. Communities are the clusters of nodes that the communication latency between the nodes are minimum values. The purpose of this study if to, by using this method, minimize the latency and access cost of the data.
Design/methodology/approach
This paper used the Louvain algorithm for finding the best communities. In the proposed algorithm, by requesting a file according to the nodes of each community, the cost of accessing the file located out of the applicant’s community was calculated and the results were accumulated. On exceeding the accumulated costs from a specified threshold, a new replica of the file was created in the applicant’s community. Besides, the number of replicas of each file should be limited to prevent the system from creating useless and redundant data.
Findings
To evaluate the method, four metrics were introduced and measured, including communication latency, response time, data access cost and data redundancy. The results indicated acceptable improvement in all of them.
Originality/value
So far, this is the first research that aims at managing the replicas via community detection algorithms. It opens many opportunities for further studies in this area.
Details
Keywords
Akhtar Rasool, Esref Emre Ozsoy, Fiaz Ahmad, Asif Sabanoviç and Sanjeevikumar Padmanaban
This paper aims to propose a novel grid current control strategy for grid-connected voltage source converters (VSCs) under unbalanced grid voltage conditions.
Abstract
Purpose
This paper aims to propose a novel grid current control strategy for grid-connected voltage source converters (VSCs) under unbalanced grid voltage conditions.
Design/methodology/approach
A grid voltage dynamic model is represented in symmetrical positive and negative sequence reference frames. A proportional controller structure with a first-order low-pass filter disturbance observer (DOB) is designed for power control in unbalanced voltage conditions. This controller is capable of meeting the positive sequence power requirements, and it also eliminates negative sequence power components which cause double-frequency oscillations on power. The symmetrical components are calculated by using the second-order generalized integrator-based observer, which accurately estimates the symmetrical components.
Findings
Proportional current controllers are sufficient in this study in a wide range of operating conditions, as DOB accurately estimates and feed-forwards nonlinear terms which may be deteriorated by physical and operating conditions. This is the first reported scheme which estimates the VSC disturbances in terms of symmetrical component decomposition and the DOB concept.
Originality/value
The proposed method does not require any grid parameter to be known, as it estimates nonlinear terms with a first-order low-pass filter DOB. The proposed control system is implemented on a dSPACE ds1103 digital controller by using a three-phase, three-wire VSC.
Details
Keywords
The purpose of this study is to analyze the slurry erosion failure of Ni-20Cr (Ni-Cr2O3), Ni-20Al (Ni-Al2O3) and Al-20Ti (Al2O3-TiO2) coatings deposited on SS316L by the…
Abstract
Purpose
The purpose of this study is to analyze the slurry erosion failure of Ni-20Cr (Ni-Cr2O3), Ni-20Al (Ni-Al2O3) and Al-20Ti (Al2O3-TiO2) coatings deposited on SS316L by the high-velocity oxy-fuel process.
Design/methodology/approach
Slurry erosion experiments were conducted using a pot type erosion tester at different velocities 1.81, 2.71, 3.61 and 4.59 m/s for the time duration of 90-180 minutes. Fly ash and bottom ash were used as erodent media; the concentration of mass flux was taken as 30-60 wt. per cent. Artificial neural network (ANN) method was used to simulate the slurry erosion for thermally sprayed coatings.
Findings
Slurry erosion of coatings increases non-linearly with an increase in experimental durations, mass flux and velocity. Slurry erosion of Ni-20Cr and Ni-20Al layers was found to be maximum at 60° impingement angle, whereas 30° for SS316L and 45° for Al-20Ti coating. Slurry erosion performance of SS316L was improved by 2.56-3.19 times by depositing Ni-20Cr and Ni-20Al layers, whereas it improved 1.15-1.75 times by Al-20Ti coating. The slurry erosion SS316L was found almost 1.35 ± 1.28 times greater than that of the Ni-20Al coating, whereas it was to be 1.12 ± 1.36 times greater than Al-20Ti. Ni-20Al-coated SS316L showed a lower value of slurry erosion than Al-20Ti-coated SS316L.
Practical implications
Stainless Steel SS316L is widely used in hydraulic machinery (such as turbines, pumps, valves, fittings, etc.) of hydraulic and thermal power plants, chemical industry and marine industry. Therefore, the deposition of ductile and brittle coatings is a better option for their durable performance.
Originality/value
Erosion wear of Ni-20Cr, Ni-20Al and Al-20Ti coatings was successfully simulated by using an artificial neural network model by supplying experimental data as a target.
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Keywords
Mojtaba Yousefi, Nasim Khorshidian and Hedayat Hosseini
The purpose of this paper is to present an overview of different aspects of inulin functionality in meat and poultry products.
Abstract
Purpose
The purpose of this paper is to present an overview of different aspects of inulin functionality in meat and poultry products.
Design/methodology/approach
Several studies on the physiochemical, textural and sensorial effects of inulin incorporated in meat and poultry products as fat replacer and texture modifier were reviewed.
Findings
Inulin is a plant-derived carbohydrate composed of fructose units and glucosyl moieties at the end of the chain that exhibits unique nutritional and technological benefits. Among its main healthy characteristics, it has been reported to reduce the risk of colon cancer, arteriosclerosis, osteoporosis, diabetes and obesity, to maintain low levels of triglycerides and cholesterol in serum and stimulate the immune system. As a functional food ingredient, it can be used in various foods as a fat replacer, improves water-holding capacity and emulsion stability, as well as modifying the texture and viscosity of foods. Incorporation of inulin into meat and poultry products can be beneficial in producing low-fat products with desirable texture and sensory attributes.
Originality/value
There are limited reviews regarding the application of inulin in meat and poultry products. In this review, chemical composition and physicochemical properties of inulin, its health effects and various effects of inulin incorporation into meat and poultry products including, physicochemical, textural and sensory characteristics of these products are discussed.
Details
Keywords
Amanda Wheeler, Amary Mey, Fiona Kelly, Laetitia Hattingh and Andrew K. Davey
The purpose of this paper is to explore the potential approaches to continuing education and training delivery for community pharmacists to equip them to support mental health…
Abstract
Purpose
The purpose of this paper is to explore the potential approaches to continuing education and training delivery for community pharmacists to equip them to support mental health consumers and carers with illnesses such as depression and anxiety.
Design/methodology/approach
Review of national and international literature about community pharmacists’ roles, beliefs and attitudes towards mental health, continuing education delivery for the workforce and training recommendations to equip pharmacy workforce.
Findings
Training involving consumer educators was effective in reducing stigma and negative attitudes. Interactive and contextually relevant training appeared to be more effective than didactic strategies. Narratives and role-plays (from the perspective of consumers, carers and health professionals) are effective in promoting more positive attitudes and reduce stigma. Flexible on-line delivery methods with video footage of expert and consumer narratives were preferable for a cost-effective programme accessible to a wide community pharmacy workforce.
Originality/value
There is a clear need for mental health education for community pharmacists and support staff in Australia. Training should target reducing stigma and negative attitudes, improving knowledge and building confidence and skills to improve pharmacy staff's perceived value of working with mental health consumers. The delivery mode should maximise uptake.