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Article
Publication date: 3 December 2021

Ali Dinc and Ali Mamedov

Glass is a brittle material produced from silica, which has fine material properties, Owing to its sophisticated material properties, glass has found wide application in various…

136

Abstract

Purpose

Glass is a brittle material produced from silica, which has fine material properties, Owing to its sophisticated material properties, glass has found wide application in various high-technological fields such as aviation, aerospace, communication, optics, biomedical and electronics. However, glass is known as difficult to machine material because of its tendency to brittle fracture during machining. This paper aims to investigate the effects of cutting parameters on surface quality and machining time during micro-milling of brittle glass components.

Design/methodology/approach

A comprehensive genetic algorithm-based optimization strategy is used for selection of process parameters such as cutting speed, feed rate and depth of cut. Effectiveness of the proposed strategy is validated by conducting micro-milling cutting experiments on soda-lime glass material.

Findings

Results showed that the generated surface quality drastically decrease with increase in the amount of removed material. Lower depth of cut and feed rate result in less amount of cracks formed on machined surface. Also, it is observed that the increase in cutting speed results in better surface quality. Having desired surface quality in shorter machining time directly reduces energy consumed during manufacturing, which is reducing environmental impact of glass parts.

Originality/value

The novelty of this research work lies in simultaneously considering the effects of cutting speed, feed rate, depth of cut on surface quality and machining time for micro-milling operation of brittle glass material. The model is able to find optimum process parameters for high surface quality and minimum machining time.

Details

Aircraft Engineering and Aerospace Technology, vol. 94 no. 5
Type: Research Article
ISSN: 1748-8842

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Article
Publication date: 23 December 2020

Ali Dinc and Murat Otkur

The purpose of this study is to perform the preliminary design, flight performance and exhaust emissions calculations of a piston engine powered unmanned aerial vehicle (UAV…

284

Abstract

Purpose

The purpose of this study is to perform the preliminary design, flight performance and exhaust emissions calculations of a piston engine powered unmanned aerial vehicle (UAV) during a flight cycle which consists of multiple flight altitudes and airspeeds.

Design/methodology/approach

A genuine computer model in Matlab/Simulink was developed to predict the size and weight of UAV and piston engine (using Avgas 100LL fuel) performance together with exhaust emissions in an iterative process.

Findings

The amount of emitted exhaust gases including carbon dioxide, carbon monoxide, hydrocarbons and nitrogen oxides were calculated in a typical UAV mission profile as a whole and also divided into mission flight segments.

Research limitations/implications

Emissions were calculated based on fuel flow and engine speed inputs based on ground test data for emission indices. Test data for emission indices was very limited.

Practical implications

As UAV utilization has been increasing around the world, this study presents important and noticeable results on the emissions that need to be considered for environmental purposes.

Originality/value

In literature, emission prediction studies for UAVs are very rare. In fact, UAVs typically have quite different flight speeds and altitudes than regular manned aircraft and emissions change with speed and altitude. Additionally, unlike manned aircraft, UAVs can fly more than 24 h with different operation characteristics. The originality of this study presents the emission predictions of a piston engine UAV which flies with a significantly different mission profile than a manned aircraft.

Details

Aircraft Engineering and Aerospace Technology, vol. 93 no. 3
Type: Research Article
ISSN: 1748-8842

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Article
Publication date: 6 August 2020

Ali Dinc, Yasin Şöhret and Selcuk Ekici

This study aims to introduce exergy analysis of a three-spool turboprop engine during the complete flight.

529

Abstract

Purpose

This study aims to introduce exergy analysis of a three-spool turboprop engine during the complete flight.

Design/methodology/approach

In this study, a flight scenario of the aircraft is assumed. Operating parameters of the aircraft and its engine are modelled based on the assumed flight scenario with the aid of a genuine code. And then performance analysis of the engine is performed for each flight path point with the aid of exergy.

Findings

At the end of the study, major exergy parameters of the engine are calculated during the complete flight of a cargo aircraft three-spool turboprop engine.

Practical implications

Findings of the study may be beneficial for industry and practitioners to improve performance of the evaluated engine.

Originality/value

To the best of authors’ knowledge, this paper presented the exergy analysis of a three-spool turboprop engine during the complete flight for the first time. It was shown how the exergy destruction rate depends on the altitude and manoeuvre.

Details

Aircraft Engineering and Aerospace Technology, vol. 92 no. 10
Type: Research Article
ISSN: 1748-8842

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Article
Publication date: 2 May 2017

Ali Dinc

This paper aims to present a genuine code developed for multi-objective optimization of selected parameters of a turboprop unmanned air vehicle (UAV) for minimum landing-takeoff…

434

Abstract

Purpose

This paper aims to present a genuine code developed for multi-objective optimization of selected parameters of a turboprop unmanned air vehicle (UAV) for minimum landing-takeoff (LTO) nitrogen oxide (NOx) emissions and minimum equivalent power specific fuel consumption (ESFC) at loiter (aerial reconnaissance phase of flight) by using a genetic algorithm.

Design/methodology/approach

The genuine code developed in this study first makes computations on preliminary sizing of a UAV and its turboprop engine by analytical method for a given mission profile. Then, to minimize NOx emissions or ESFC or both of them, single and multi-objective optimization was done for the selected engine design parameters.

Findings

In single objective optimization, NOx emissions were reduced by 49 per cent from baseline in given boundaries or constraints of compressor pressure ratio and compressor polytropic efficiency in the first case. In second case, ESFC was improved by 25 per cent from baseline. In multi-objective optimization case, where previous two objectives were considered together, NOx emissions and ESFC decreased by 26.6 and 9.5 per cent from baseline, respectively.

Practical implications

Variation and trend in the NOx emission index and ESFC were investigated with respect to two engine design parameters, namely, compressor pressure ratio and compressor polytropic efficiency. Engine designers may take into account the findings of this study to reach a viable solution for the bargain between NOx emission and ESFC.

Originality/value

UAVs have different flight mission profiles or characteristics compared to manned aircraft. Therefore, they are designed in a different philosophy. As a number of UAV flights increase in time, fuel burn and LTO NOx emissions worth investigating due to operating costs and environmental reasons. The study includes both sizing and multi-objective optimization of an UAV and its turboprop engine in coupled form; compared to manned aircraft.

Details

Aircraft Engineering and Aerospace Technology, vol. 89 no. 3
Type: Research Article
ISSN: 1748-8842

Keywords

Available. Open Access. Open Access

Abstract

Details

Journal of Intelligent Manufacturing and Special Equipment, vol. 4 no. 1
Type: Research Article
ISSN: 2633-6596

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Article
Publication date: 22 February 2021

Nuri Gökhan Torlak, Cemil Kuzey, Muhammet Sait Dinç and Ali Haydar Güngörmüş

The paper aims to analyze the relationships between ethical leadership (EL), job satisfaction (JS), affective commitment (AC) and turnover intention (TI) that might make…

1181

Abstract

Purpose

The paper aims to analyze the relationships between ethical leadership (EL), job satisfaction (JS), affective commitment (AC) and turnover intention (TI) that might make accountants quit withdrawal and become productive and useful in private organizations operating in Istanbul.

Design/methodology/approach

Data were collected through an online survey using a simple random sampling methodology, obtained from 153 accountants working in companies in Istanbul. The methodology included descriptive statistics, factor analysis, structural equation modeling and mediation analysis.

Findings

Concerning direct relationships between EL, JS, AC and TI, EL has significant positive associations with JS and AC, whereas EL has a significant negative association with TI. JS has a significant positive association with AC, whereas JS has a significant negative association with TI. Also, AC has a weak significant negative association with TI. Given indirect relationships among EL, JS, AC and TI, JS and AC mediate the relationship between EL and TI. Finally, a similarity is found when comparing Generation X and Generation Y in terms of overall JS, AC and TI.

Research limitations/implications

The study is limited solely to companies functioning in Istanbul and incorporates a low number of respondents. Therefore, the results cannot be considered to be accurate for the whole country. The study might guide both private and public organizations in which owners/managers develop strategic plans.

Originality/value

The study fills the gap in research on organizational behavior where little has existed until now that probes the EL–JS–AC–TI links in Turkey. A few studies measure the TIs of accountants. Furthermore, EL and AC are rarely evaluated in the field of accounting in Turkey.

Details

Journal of Modelling in Management, vol. 16 no. 2
Type: Research Article
ISSN: 1746-5664

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Article
Publication date: 29 September 2022

Rizaldi Yusfiarto, Septy Setia Nugraha, Lu’liyatul Mutmainah, Izra Berakon, Sunarsih Sunarsih and Achmad Nurdany

This study aims to explore the Islamic capital market adoption model, based on the construct of Islamic financial literacy (IFL), the theory of planned behavior (TPB) and past…

1487

Abstract

Purpose

This study aims to explore the Islamic capital market adoption model, based on the construct of Islamic financial literacy (IFL), the theory of planned behavior (TPB) and past behavior (PBR) in the context of a Muslim-majority country (Indonesia).

Design/methodology/approach

To test the conceptual model, this study used data from 251 respondents with a diverse spectrum, and the partial least squares structural equation modeling technique was used to test the forecasting of the model.

Findings

Overall, IFL and TPB dimensions (i.e. attitudes and perceived behavioral control) have a significant positive effect, either directly or indirectly, for investment intentions in the Islamic capital market. Also, the findings recommend the construct of PBR as an important predictor of investment intentions in Islamic capital markets.

Practical implications

The study can be beneficially used for Islamic financial institutions to participate with the Indonesian government in affirming IFL to broader society, not only Islamic education institutions. It is related to the significance of IFL, where it can be utilized as an indicator that education on the concept and values of Islamic finance can positively establish attitudes in society and stakeholders.

Originality/value

This study is an effort to strengthen IFL as a key construct using a good measurement scale, in the context of the Islamic capital market investment. In addition, this study also provides the necessary impetus to analyze the relationship between the dimensions of TPB and PBR, either directly or indirectly.

Details

Journal of Islamic Accounting and Business Research, vol. 14 no. 4
Type: Research Article
ISSN: 1759-0817

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Article
Publication date: 14 February 2023

Yusuf Dinc, Mehmet Çetin and Rashed Jahangir

There is a growing body of literature that recognizes the importance of Islamic financial literacy (IFL) while it is at the heart of our understanding of the overall financial…

426

Abstract

Purpose

There is a growing body of literature that recognizes the importance of Islamic financial literacy (IFL) while it is at the heart of our understanding of the overall financial system. To date, insufficient attention has been paid to Turkey, the Balkans and other potential Islamic finance hubs like Suriname. In fact, there have been no attempts to examine IFL in those regions or economies. The purpose of this paper is to test and validate the IFL scale developed by Dinc et al. (2021) in an international setting. By doing so, this study elaborates on possible antecedents and levels of IFL across countries and economic systems.

Design/methodology/approach

The design of the questionnaire used is based on the principles of Islamic finance and covers all the segments. The total number of collected observations is 3,579. This study uses the confirmatory factor analysis (CFA) to ascertain the factor structure and test the revised scale fit with the original form. Besides, IBM AMOS 25 Graphics is used for calculating the fit indexes for the scale.

Findings

The results from the CFA revealed that the scale has a good fit for its original and kept the four-dimensional structure. In addition, it also indicates that the predeveloped IFL scale is valid for different cultures, countries and individuals either having conventional or Islamic financial institutions preferences. Furthermore, results of empirical tests demonstrate that Turkey is significantly higher in Islamic financial awareness, whereas other countries' group is higher on all other subdimensions of the scale. On the other hand, female respondents indicate significantly higher levels of Islamic financial awareness, and male respondents show significantly higher levels of Islamic financial knowledge. Finally, the most prominent finding to emerge from the analysis is that the principles of Islamic finance are well accepted, except for some liberal views on the concept of “interest” (riba).

Research limitations/implications

Because of the diverse demography of the collected sample observations, this revised scale has a homogeneous set of implications. This IFL scale can accurately measure the level of IFL attained by an individual, group, society or nation, as well as suggest necessary actions based on its four-dimensional structure.

Originality/value

This study tests the IFL scale by considering two key elements: increased sample size and vast geographical coverage. To ensure that the developed scale is universal, this study took into account more than 3,000 observations from 28 different countries. These amendments ensure the uniqueness of this paper and its originality.

Details

Journal of Islamic Accounting and Business Research, vol. 14 no. 8
Type: Research Article
ISSN: 1759-0817

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Article
Publication date: 18 March 2022

Martin Dixon

The purpose of this paper is to analyse whether title to land is secure in England and Wales when registered under the Land Registration Act (LRA) 2002, in particular when a title…

612

Abstract

Purpose

The purpose of this paper is to analyse whether title to land is secure in England and Wales when registered under the Land Registration Act (LRA) 2002, in particular when a title is registered, where there has been a mistake and how that connects with the doctrine of overreaching.

Design/methodology/approach

This paper analyses the reported judgments, with particular emphasis on the decision in Knight v Fernley (2021).

Findings

This paper explores the concepts of “mistake” and “overreaching” and concludes that LRA 2002 provides a complex, but complete answer to concerns about the application of these doctrines.

Practical implications

This paper will encourage certainty in the judicial decision-making process when “mistakes” occur in the land register. It will contribute to the resolution of difficult, and current, controversies.

Social implications

To enable legal advisers to be clear in their obligations and the advice they give to clients, and to further a better understanding of title registration in England and Wales.

Originality/value

The LRA 2002 replaces registration of title with title by registration. The real force of this is only now being realised and there are few reported judgments, and less consistency, working out what this means in practice. There are no other comments on this critical case, even though it helps elucidate the circumstances in which the title register may be altered.

Details

Journal of Property, Planning and Environmental Law, vol. 14 no. 1
Type: Research Article
ISSN: 2514-9407

Keywords

Available. Open Access. Open Access
Article
Publication date: 12 April 2021

Nicholas M. Odhiambo

This study examines the causal relationship between exports and economic growth in sub-Saharan African (SSA) countries during the period 1980 to 2017. The study also examines…

3202

Abstract

Purpose

This study examines the causal relationship between exports and economic growth in sub-Saharan African (SSA) countries during the period 1980 to 2017. The study also examines whether the causality between these two macroeconomic variables depends on the countries' stage of development as proxied by their per capita income.

Design/methodology/approach

The study uses a panel cointegration test and panel Granger-causality model to examine the link between exports and growth. The study also incorporates external debt as an intermittent variable in a bivariate setting between exports and economic growth, thereby creating a dynamic multivariate panel Granger-causality model.

Findings

Although the study found the existence of a long-run relationship between exports and economic growth, the study failed to find any export-led growth response in both low-income and middle-income countries. Instead, the study found evidence of a bidirectional causality and a neutrality response in middle-income and low-income countries, respectively. The study, therefore, concludes that the benefits of an export-led growth hypothesis may have been oversold, and that the strategy may not be desirable to some low-income developing countries.

Practical implications

These findings have important policy implications as they indicate that the causality between exports and economic growth in SSA countries varies with the countries' stage of development. Consistent with the contemporary literature, the study cautions low-income SSA countries against over-relying on an export-led growth strategy to achieve a sustained growth path as no causality between exports and economic growth has been found to exist in those countries. Instead, such countries should consider pursuing new growth strategies by building the domestic demand side of their economies alongside their export promotion strategies in order to expand the real sector of their economies. For middle-income countries, the study recommends that both export promotion strategies and pro-growth policies should be intensified as economic growth and exports have been found to reinforce each other in those countries.

Originality/value

Unlike the previous studies, the current study disaggregated the full sample of SSA countries into two subsets – one comprising of low-income countries and the other consisting of middle-income countries. In addition, the study uses a multivariate Granger-causality model in order to address the emission-of-variable bias. To our knowledge, this may be the first study of its kind in recent years to examine in detail the causal relationship between exports and economic growth in SSA countries using an ECM-based multivariate panel Granger-causality model.

研究目的

本研究旨在探討在1980年至2017年期間撒哈拉以南非洲國家的出口、與其經濟增長之間的因果關係,亦探討這兩個宏觀經濟變量之間的因果關係、會否取決於有關國家所處以人均收入來衡量的發展階段。

研究結果

本研究雖然發現出口與經濟增長存有一個長期性關係,唯未能於低收入國家或中等收入國家、找到任何出口帶動的增長反應。研究反而找到證據,證實中等收入國家為一雙向性因果關係反應,而低收入國家則為一中立性反應。因此,研究的結論是:出口必能帶動經濟增長這假設被過度吹噓,而且,對部份低收入發展中國家而言,實施以出口帶動經濟增長的策略或許是沒有用的。

實際意義

本研究的結果在政策方面有其重要意義。這是因為研究結果顯示、於撒哈拉以南非洲國家、出口與經濟增長之間的因果關係,會因有關國家所處的發展階段而有所變更。與當代文獻一樣,本研究提醒低收入的撒哈拉以南非洲國家,不要過度依賴以出口帶動增長的策略來謀求踏上持續增長之路,這是因為在這些國家,出口與經濟增長之間的因果關係仍未確立。他們反而應考慮推行新增長經濟策略,方法是在實施推動出口的策略的同時,也要建立其經濟的國內需求面,以擴大其經濟實業部門。就中等收入國家而言,本研究建議他們應增強推動出口的策略及強化促進增長的政策,這是因為在這些國家裏,經濟增長及出口已被證實會互為增強。

原創性/價值

有別於過去的研究,本研究把撒哈拉以南非洲國家的整體樣本分解為兩個子集:一個包括低收入國家,另一個則包括中等收入國家。而且、研究使用了多變量面板格蘭傑因果關係模型、以處理遺漏變數偏差的問題。據我們了解,這大概是近年首個同類研究、以基於歐洲共同市場多變量面板格蘭傑因果關係模型、來詳細探討於撒哈拉以南非洲國家、出口與經濟增長之間的因果關係。

Details

European Journal of Management and Business Economics, vol. 31 no. 1
Type: Research Article
ISSN: 2444-8451

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