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Article
Publication date: 5 August 2014

Rajesh Siriyala, A. Gopala Krishna, P. Rama Murthy Raju and M. Duraiselvam

Since, wear is the one of the most commonly encountered industrial problems leading to frequent replacement of components there is a need to develop metal matrix…

Abstract

Purpose

Since, wear is the one of the most commonly encountered industrial problems leading to frequent replacement of components there is a need to develop metal matrix composites (MMCs) for achieving better wear properties. The purpose of this paper is to fabricate aluminum MMCs to improve the dry sliding wear characteristics. An effective multi-response optimization approach called the principal component analysis (PCA) was used to identify the sets of optimal parameters in dry sliding wear process.

Design/methodology/approach

The present work investigates the dry sliding wear behavior of graphite reinforced aluminum composites produced by the molten metal mixing method by means of a pin-on-disc type wear set up. Dry sliding wear tests were carried on graphite reinforced MMCs and its matrix alloy sliding against a steel counter face. Different contact stress, reinforcement percentage, sliding distance and sliding velocity were selected as the control variables and the response selected was wear volume loss (WVL) and coefficient of friction (COF) to evaluate the dry sliding performance. An L25 orthogonal array was employed for the experimental design. Optimization of dry sliding performance of the graphite reinforced MMCs was performed using PCA.

Findings

Based on the PCA, the optimum level parameters for overall principal component (PC) of WVL and COF have been identified. Moreover, analysis of variance was performed to know the impact of individual factors on overall PC of WVL and COF. The results indicated that the reinforcement percentage was found to be most effective factor among the other control parameters on dry sliding wear followed by sliding distance, sliding velocity and contact stress. Finally the wear surface morphology of the composites has been investigated using scanning electron microscopy.

Practical implications

Various manufacturing techniques are available for processing of MMCs. Each technique has its own advantages and disadvantages. In particular, some techniques are significantly expensive compared to others. Generally the manufacturer prefers the low cost technique. Therefore stir casting technique which was used in this paper for manufacturing of Aluminum MMCs is the best alternative for processing of MMCs in the present commercial sectors. Since the most important criteria of a dry sliding wear behavior is to provide lower WVL and COF, this study has intended to prove the application of PCA technique for solving multi objective optimization problem in wear applications like piston rings, piston rods, cylinder heads and brake rotors, etc.

Originality/value

Application of multi-response optimization technique for evaluation of tribological characteristics for Aluminum MMCs made up of graphite particulates is a first-of-its-kind approach in literature. Hence PCA method can be successfully used for multi-response optimization of dry sliding wear process.

Details

Multidiscipline Modeling in Materials and Structures, vol. 10 no. 2
Type: Research Article
ISSN: 1573-6105

Keywords

Article
Publication date: 31 July 2019

Mohammad Mohsen Peiravi, Javad Alinejad, D.D. Ganji and Soroush Maddah

The purpose of this study is investigating the effect of using multi-phase nanofluids, Rayleigh number and baffle arrangement simultaneously on the heat transfer rate and…

Abstract

Purpose

The purpose of this study is investigating the effect of using multi-phase nanofluids, Rayleigh number and baffle arrangement simultaneously on the heat transfer rate and Predict the optimal arrangement type of baffles in the differentiation of Rayleigh number in a 3D enclosure.

Design/methodology/approach

Simulations were performed on the base of the L25 Taguchi orthogonal array, and each test was conducted under different height and baffle arrangement. The multi-phase thermal lattice Boltzmann based on the D3Q19 method was used for modeling fluid flow and temperature fields.

Findings

Streamlines, isotherms, nanofluid volume fraction distribution and Nusselt number along the wall surface for 104 < Ra < 108 have been demonstrated. Signal-to-noise ratios have been analyzed to predict optimal conditions of maximize and minimize the heat transfer rate. The results show that by choosing the appropriate height and arrangement of the baffles, the average Nusselt number can be changed by more than 57 per cent.

Originality/value

The value of this paper is surveying three-dimensional and two-phase simulation for nanofluid. Also using the Taguchi method for Predicting the optimal arrangement type of baffles in a multi-part enclosure. Finally statistical analysis of the results by using of two maximum and minimum target Function heat transfer rates.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 30 no. 5
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 6 November 2017

Mohd Muqeem, Ahmad Faizan Sherwani, Mukhtar Ahmad and Zahid Akhtar Khan

Diesel engine can produce power more efficiently with lower exhaust emissions when operated at optimum input parameter settings. To achieve this goal, the purpose of this…

Abstract

Purpose

Diesel engine can produce power more efficiently with lower exhaust emissions when operated at optimum input parameter settings. To achieve this goal, the purpose of this paper is to optimize the input parameters of diesel engine which will lead to optimum performance and exhaust emissions.

Design/methodology/approach

To achieve the goal of improving diesel engine performance and exhaust emissions, four input parameters were considered in the study. Five different levels of each input parameter were taken. Four response variables under no load, half load and full load conditions were recorded. Experiments were performed in random manner according to selected Taguchi L25 orthogonal array. The data were analyzed using grey relational analysis coupled with principal component analysis. Analysis of S/N ratio was performed to obtain the optimum combination of input parameters. The grey relational grade at optimum setting of the input parameters was obtained by regression analysis.

Findings

Results of the current research work give the optimum input parameter settings for no load, half load and full load conditions of diesel engine. Engine produces power more efficiently with low exhaust emissions when operated at these optimum settings.

Practical implications

In view of the compliance to the stringent air pollution norms of the nations and fast depleting fossil fuels, it is of the utmost importance to design and operate the engine in the optimum range of its input parameters so that it produces more power with low exhaust emissions. This paper aims at optimizing input parameters of diesel engine to improve performance and exhaust emissions. Results of the study presented in this paper are significantly useful for diesel engine-related researchers and professionals.

Originality/value

From the literature review, it appears that only few researchers have conducted studies pertaining to the optimization of the input parameters of diesel engine to improve performance or exhaust emissions. Although few studies related to the optimization of compression ratio, fuel injection timing, fuel injection pressure and air pressure have been reported, no work related to optimization of temperature and pressure of turbocharged air has been reported. Therefore, the main focus of the current research work is on optimizing the charge air temperature and pressure with respect to performance and exhaust emissions.

Details

Grey Systems: Theory and Application, vol. 7 no. 3
Type: Research Article
ISSN: 2043-9377

Keywords

Article
Publication date: 6 February 2020

Víctor Giménez, Diego Prior and Jorge R. Keith

This paper aims to investigate the efficiency implications of belonging to a strategic hospital alliance (SHA) and measuring the effects over capacity utilization of such…

Abstract

Purpose

This paper aims to investigate the efficiency implications of belonging to a strategic hospital alliance (SHA) and measuring the effects over capacity utilization of such agreements in a Mexican healthcare context.

Design/methodology/approach

Data Envelopment Analysis (DEA) is the nonparametric methodology used, which supports both objectives. Technological gaps ratios are calculated by using DEA-metafrontier approach to compare efficiency between SHA members and a hospital’s control group. Also, hospital capacity utilization ratios are used as the maximum rate of output possible from fixed inputs in a frontier setting using directional distance functions. Data were collected from an alliance called Consorcio Mexicano de Hospitales in México, which has 29 general private hospitals and a group of 47 hospitals with same characteristics from a database made by the Instituto Nacional de Estadística y Geografía for year 2014.

Findings

The results indicate that efficiency is better at hospitals that belong to an alliance; it also shows an improvement of installed capacity management for hospital alliances in México.

Originality/value

The results can be useful for both private health organization managers and regulators themselves to adopt management practices that may end up having a favorable impact on cost and prices containment. Additionally, there are no previous studies neither in Mexico nor in Latin America that analyze the impact of strategic hospitality alliances on the efficiency and utilization of the capacity of private hospitals.

Propósito

Este documento tiene como objetivo investigar las implicaciones de pertenecer a una alianza hospitalaria estratégica (AHE) en la eficiencia, así como cuantificar los efectos sobre la utilización de la capacidad de dichos acuerdos en el contexto mexicano de atención médica.

Diseño/metodología/enfoque

El Análisis Envolvente de Datos (DEA) es la metodología no paramétrica utilizada para lograr ambos objetivos. Las brechas tecnológicas se estiman empleando meta-fronteras calculadas mediante modelos DEA, comparando la eficiencia entre los miembros de la AHE y un grupo de control de hospitales. El nivel de utilización de la capacidad hospitalaria se calcula, utilizando funciones direccionales de distancia, a partir del máximo output alcanzable a partir de la dotación de inputs fijos. Los datos fueron obtenidos de la alianza Consorcio Mexicano de Hospitales en México, integrada por 29 hospitales privados generales, y de un grupo de 47 hospitales con las mismas características obtenidos de una base de datos del Instituto Nacional de Estadística y Geografía para el año 2014.

Resultados

adosLos resultados indican que los niveles de eficiencia son superiores en los hospitales pertenecientes a la alianza, así como una mejor gestión de la capacidad instalada en la alianza hospitalaria en México.

Originalidad/valor

Los resultados pueden ser útiles tanto para los administradores de las organizaciones de salud privadas como para los reguladores, de forma que puedan adoptar prácticas de gestión con un impacto favorable en la contención de costos y precios. Asimismo, no existen estudios previos ni en México ni en América Latina que analicen el impacto de las alianzas estratégicas hospitalarias en la eficiencia y la utilización de la capacidad de los hospitales privados.

Article
Publication date: 20 July 2022

Zakaria Elouaourti and Elhadj Ezzahid

Do financial services needs depend on the firm size? To highlight the impact of different categories of financial services on firm performance, we establish a…

Abstract

Purpose

Do financial services needs depend on the firm size? To highlight the impact of different categories of financial services on firm performance, we establish a correspondence between financial services and firms' performance classified according to their size, controlling with the determinants of firm performance and the obstacles that hinder the development of each category of firm.

Design/methodology/approach

We have mobilized microeconomic data on 78,629 firms stratified by size and covering 135 countries, extracted from the Enterprise Surveys database. A two-stage least squares (2SLS) regression analysis with instrumental variable modeling is used.

Findings

Our empirical results show that a firm's financing behavior differs according to its size. For micro and small firms, the availability of internal financing has a positive impact on their performance. For medium-size firms, the use of debt stimulates firm performance. For large firms, the positive effect of debt diminishes as the level of debt increases, which leads this category of firms to increase their capital. We complemented our study by exploring the issue of whether barriers to firm performance differ by size. Our results bring a support to the idea that medium-size firms suffer more than micro, small, and large firms. The size of this category of firms does not allow them to operate in the informal sector as micro and small firms do, and does not allow them to influence political authorities to operate in their favor as large firms do.

Originality/value

Previous studies have focused on investigating the effects of access to finance and/or financing constraints on firm's performance, neglecting the issue of identifying which financial services have the most impact on firm performance depending on firms' size. This study fills the gap in the literature in two main ways. First, we identify the financial services that have the most impact on firm performance using firm-level data covering 78,629 firms by size (micro, small, medium, and large). Second, we investigate the different barriers to firm performance by size.

Details

Journal of Economic Studies, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0144-3585

Keywords

Article
Publication date: 8 June 2022

Valiollah Panahizadeh, Amir Hossein Ghasemi, Yaghoub Dadgar Asl and Mohammadmahdi Davoudi

This paper aims to study multiobjective genetic algorithm ability in determining the process parameter and postprocess condition that leads to maximum relative density…

Abstract

Purpose

This paper aims to study multiobjective genetic algorithm ability in determining the process parameter and postprocess condition that leads to maximum relative density (RD) and minimum surface roughness (Ra) simultaneously in the case of a Ti6Al4V sample process by laser beam powder bed fusion.

Design/methodology/approach

In this research, the nondominated sorting genetic algorithm II is used to achieve situations that correspond to the highest RD and the lowest Ra together.

Findings

The results show that several situations cause achieving the best RD and optimum Ra. According to the Pareto frontal diagram, there are several choices in a close neighborhood, so that the best setup conditions found to be 102–105 watt for laser power followed by scanning speed of 623–630 mm/s, hatch space of 76–73 µm, scanning patter angle of 35°–45° and heat treatment temperature of 638–640°C.

Originality/value

Suitable selection of process parameters and postprocessing treatments lead to a significant reduction in time and cost.

Details

Rapid Prototyping Journal, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 17 June 2022

Hung Son Tran, Thanh Dat Nguyen and Thanh Liem Nguyen

The purpose of this study is to carry out an empirical investigation about how the level of market concentration or competitiveness of the banking system and institutional…

Abstract

Purpose

The purpose of this study is to carry out an empirical investigation about how the level of market concentration or competitiveness of the banking system and institutional quality are associated with bank’s financial stability.

Design/methodology/approach

This study uses dynamic panel data techniques on the sample of 133 developing and emerging countries over the years 2002–2020.

Findings

The authors document several significant findings. First, there is evidence that bank stability is positively associated with the level of market concentration. The result is in line with the concentration–stability view that banks operating in a more concentrated market tend to be more stable than those in a less concentrated market. Second, the results confirm that the quality of the institutional environment plays a critical role in improving the stability of banks in developing and emerging countries. Third, the authors find that institutional development can moderate the effect of market concentration (or competitiveness of the banking system) on bank stability. Specifically, the results show that better institutional quality enhances the positive influence of bank concentration on the bank’s financial stability in developing and emerging countries. These results are robust to different specifications with the alternative measures of bank stability and market concentration.

Originality/value

This study provides further understanding regarding the effects of the level of market concentration or competitiveness of the banking system and institutional quality on bank stability in 133 developing and emerging countries over the years 2002–2020.

Details

Competitiveness Review: An International Business Journal , vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1059-5422

Keywords

Article
Publication date: 24 May 2022

Ebaidalla M. Ebaidalla

This paper examines the determinants of participation in non-farm activities in rural Sudan. It also investigates whether the factors that influence participation in…

Abstract

Purpose

This paper examines the determinants of participation in non-farm activities in rural Sudan. It also investigates whether the factors that influence participation in non-farm activities vary across agriculture sub-sectors.

Design/methodology/approach

The study adopts the multinomial logit and probit methods on labour supply participation theory using the Sudanese National Baseline Household Survey (2009). The analysis was applied across job types and agriculture sub-sectors.

Findings

The results indicated that educational level, means of transportation, lack of land and access to formal agricultural credit are the most significant factors that push rural farmers to participate in non-farm activities. Surprisingly, the effect of household income was positive and significant, implying that individuals from rich households have higher opportunity to engage in non-farm activities compared to their poor counterparts. The results also revealed some variations in the factors that influence participation in non-farm activities according to the agricultural sub-sectors.

Originality/value

The originality of this article lies in investigating the factors that influence participation in non-farm activities across irrigated and rainfed systems. To the best of our knowledge, this is the first study identifying the determinants of participation in non-farm activities across agriculture sub-sectors. Therefore, the paper fills an important gap in the literature and helps in designing appropriate pro-poor policies to allocate infrastructures across irrigated and rainfed areas in Sudan.

Peer review

The peer review history for this article is available at https://publons.com/publon/10.1108/IJSE-02-2022-0092.

Details

International Journal of Social Economics, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0306-8293

Keywords

Article
Publication date: 20 May 2022

Md. Musfiqur Rahman and Md. Shuvo Howlader

The main purpose of the study is to analyze the impact of research and development (R&D) expenditure on firm performance and firm value in an emerging economy.

Abstract

Purpose

The main purpose of the study is to analyze the impact of research and development (R&D) expenditure on firm performance and firm value in an emerging economy.

Design/methodology/approach

In this study, firm performance is examined by firm financial performance (return on asset (ROA) and return on equity (ROE)) and market performance (Tobin's Q (TBQ)). This study conducted a multivariate analysis on the sampled data using pooled ordinary least square (OLS) regression method. In addition, both the level and lagged models have been used to test hypothesis in order to get the results.

Findings

All the empirical results from different models found significant and positive association of R&D expenditure with firm performance and firm value. The study also validates that all results are robust and free from outliers and multicollinearity issues.

Research limitations/implications

Most of the studies regarding the R&D expenditure and its impact were conducted on developed countries addressing only firm performance. Whereby, this study examined the impact of R&D expenditure on both firm's financial performance and market performance as well as firm value in the context of an emerging economy.

Practical implications

The outcomes of the study will enable the entrepreneurs, managers, investors and policymakers with more confidence to invest in R&D expenditure that will also ensure the organizational sustainability in the long run.

Originality/value

Most of the prior studies regarding the R&D expenditure and its impact were conducted on developed countries addressing only firm performance. Herein, both firm's financial performance and market performance along with firm value have been analyzed in the context of an emerging economy. This paper is unique empirical research study due to different institutional and regulatory setting as well as corporate characteristics. This study strongly advocates the organizational learning theory, agency theory and resource-based view theory of firms' allocation of funds for future growth and innovation.

Details

Journal of Applied Accounting Research, vol. 23 no. 4
Type: Research Article
ISSN: 0967-5426

Keywords

Book part
Publication date: 14 December 2018

Clement Kong Wing Chow and Michael Ka Yiu Fung

Service quality has become an important area for competition among Chinese carriers. This paper focuses on studying the relationship between customer satisfaction measured…

Abstract

Service quality has become an important area for competition among Chinese carriers. This paper focuses on studying the relationship between customer satisfaction measured by customer complaints and their expectation of the on-time performance of Chinese carriers and how the customer complaints affect the financial performance of carriers. By using a quarterly balanced panel data set covering six large listed carriers, the empirical results show that an increase in actual on-time performance reduces customer complaints. However, an increase in expected on-time performance significantly raises customer complaints. An increase in customer complaint reduces the yield measured as revenue per revenue ton kilometer (RTK) of carriers.

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