Search results

1 – 10 of over 1000
Article
Publication date: 1 January 1958

E.B. Backensto, R.D. Drew and J.N. Vlachos

Catalytic reforming has grown rapidly during the past six years, reaching over a million barrels daily. This acceptance is largely due to the effectiveness of catalytic reforming…

Abstract

Catalytic reforming has grown rapidly during the past six years, reaching over a million barrels daily. This acceptance is largely due to the effectiveness of catalytic reforming as a source of low‐sulphur, high‐octane motor fuels; aromatics for petro‐chemicals and low‐cost hydrogen are valuable by‐products. Some ten competitive processes are available to the refiners. Of the processes available, those using a platinum‐type catalyst have found the widest acceptance. Of the nearly 200 units in operation or under construction, over 90% use a platinum‐containing catalyst.

Details

Anti-Corrosion Methods and Materials, vol. 5 no. 1
Type: Research Article
ISSN: 0003-5599

Article
Publication date: 1 February 1958

E.B. Backensto, R.D. Drew and J.N. Vlachos

This article deals with the corrosion test results obtained in the second commercial sovaformer (static‐bed reformer utilising a platinum‐type catalyst) at Augusta. Data obtained…

Abstract

This article deals with the corrosion test results obtained in the second commercial sovaformer (static‐bed reformer utilising a platinum‐type catalyst) at Augusta. Data obtained, on a wide variety of commonly used steels, again agree well with data obtained in the laboratory.

Details

Anti-Corrosion Methods and Materials, vol. 5 no. 2
Type: Research Article
ISSN: 0003-5599

Article
Publication date: 25 January 2019

Fatih Selimefendigil, Hakan F. Öztop and Ali J. Chamkha

Numerical study of nanofluid forced convection within a branching channel was performed under the influence of a uniform magnetic field. The purpose of this study is to enhance…

Abstract

Purpose

Numerical study of nanofluid forced convection within a branching channel was performed under the influence of a uniform magnetic field. The purpose of this study is to enhance the heat transfer performance of the separated flow at the branching channel with the use of magnetic field and nanofluid. The use of magnetic field and enhancement in both the thermal conductivity and electrical conductivity with the inclusion of the nanoparticles provides favorable thermophysical properties of the nanofluid when it used as a heat transfer fluid in a branching channel. The results of this study may be used to control the thermal performance in a branching channel and further optimization studies in the presence of magnetic field.

Design/methodology/approach

Galerkin weighted residual finite element method was used for the simulations. The numerical simulation results are performed by changing the inclination angle of the lower branching channel (between 0° and 90°), thermophysical properties of the fluid via inclusion of nanoparticles (between 0 and 0.04), Reynolds number (between 100 and 400) and magnetic field strength (Hartmann number changes between 0 and 15).

Findings

It was observed that the recirculation zones and reattachment length of the upper and lower branching channels are affected by the variation of those parameters. Reattachment lengths increase with the augmentation of the Reynolds number and deterioration of the Hartmann number. Average Nusselt number becomes higher for higher values of Hartmann number and solid particle volume fraction. Inclusion of the nanoparticle to the base fluid is very effective for the configuration with higher values of Hartmann number. An optimum value of the inclination angle of the lower branching channel is observed, beyond which heat transfer rate is significantly reduced due to the establishment of a large vortex in the upper branching channel and restriction of the fluid motion.

Originality/value

In this study, forced convection of nanofluid flow in a branching channel under the effect of magnetic field was numerically studied. Magnetic field effects with nanoparticle inclusion to the base fluid on the convective heat transfer was analyzed for various inclination angles of the lower branching channel. Flow separation at the junction of the channels and thus convective heat transfer rate are influenced by the variation of these parameters. There are many studies related to application of the magnetic field with nanofluids, and a few of them are related to configurations with separated flows. To the best of the authors’ knowledge, there exist no studies for the application of nanofluids and magnetic field for the convective heat transfer in a branching channel. This topic is of importance as there are many engineering applications of the branching channels.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 30 no. 4
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 16 September 2020

Ilias Vlachos

This study aims to investigate how contract design influences supplier performance. This study synthesises three theoretical views (efficiency, relational, contingency) and…

Abstract

Purpose

This study aims to investigate how contract design influences supplier performance. This study synthesises three theoretical views (efficiency, relational, contingency) and provides empirical support on how effective contract design improves supplier performance.

Design/methodology/approach

This study reviewed contract design literature and uncovered 18 factors that may impact supplier performance. Multi-criteria, decision-making analysis examined the impact of contract factors on three supplier groups: average-, over- and under-performers. Procurement experts working with a large multinational company dealing with hundreds of procuring contracts, yearly, provided their judgement on the impact of these factors on supplier performance. Semi-structured interviews with experts and other evidence were used for data and method triangulation.

Findings

Results show that contracting with under- and over- performers presents significant differences: in the case of over-performers, contracts have a dual, yet discrete, efficiency and relational role: at transaction level, they emphasise formality, protect from opportunism and include both liquidated damages and legal action clauses. At relational level, they focus on relational learning and incentivising suppliers. However, in the case of under-performers, contracts appear to focus on contingency factors, which can be a source of ambiguity, particularly in complex environments, and trust, which has a negative impact on supplier performance.

Social implications

Improving contract design can help reduce partner opportunism, reduce inter-firm conflicts and avoid disputes that can bear a social cost. This study demonstrates that companies can use advanced analytical tools to reflect upon their own decision-making process of contact design in making transparent supplier performance assessments.

Originality/value

To the author’s knowledge, this is the first study using decision-making techniques to enhance supplier performance by improving the contract design process.

Details

International Journal of Productivity and Performance Management, vol. 70 no. 7
Type: Research Article
ISSN: 1741-0401

Keywords

Book part
Publication date: 20 October 2015

Mohammad Shamsuddoha

Contemporary literature reveals that, to date, the poultry livestock sector has not received sufficient research attention. This particular industry suffers from unstructured…

Abstract

Contemporary literature reveals that, to date, the poultry livestock sector has not received sufficient research attention. This particular industry suffers from unstructured supply chain practices, lack of awareness of the implications of the sustainability concept and failure to recycle poultry wastes. The current research thus attempts to develop an integrated supply chain model in the context of poultry industry in Bangladesh. The study considers both sustainability and supply chain issues in order to incorporate them in the poultry supply chain. By placing the forward and reverse supply chains in a single framework, existing problems can be resolved to gain economic, social and environmental benefits, which will be more sustainable than the present practices.

The theoretical underpinning of this research is ‘sustainability’ and the ‘supply chain processes’ in order to examine possible improvements in the poultry production process along with waste management. The research adopts the positivist paradigm and ‘design science’ methods with the support of system dynamics (SD) and the case study methods. Initially, a mental model is developed followed by the causal loop diagram based on in-depth interviews, focus group discussions and observation techniques. The causal model helps to understand the linkages between the associated variables for each issue. Finally, the causal loop diagram is transformed into a stock and flow (quantitative) model, which is a prerequisite for SD-based simulation modelling. A decision support system (DSS) is then developed to analyse the complex decision-making process along the supply chains.

The findings reveal that integration of the supply chain can bring economic, social and environmental sustainability along with a structured production process. It is also observed that the poultry industry can apply the model outcomes in the real-life practices with minor adjustments. This present research has both theoretical and practical implications. The proposed model’s unique characteristics in mitigating the existing problems are supported by the sustainability and supply chain theories. As for practical implications, the poultry industry in Bangladesh can follow the proposed supply chain structure (as par the research model) and test various policies via simulation prior to its application. Positive outcomes of the simulation study may provide enough confidence to implement the desired changes within the industry and their supply chain networks.

Details

Sustaining Competitive Advantage Via Business Intelligence, Knowledge Management, and System Dynamics
Type: Book
ISBN: 978-1-78560-707-3

Keywords

Book part
Publication date: 28 September 2015

Arief Rahman

Citizens are substantial stakeholders in every e-government system, thus their willingness to use and ability to access the system are critical. Unequal access and information and…

Abstract

Citizens are substantial stakeholders in every e-government system, thus their willingness to use and ability to access the system are critical. Unequal access and information and communication technology usage, which is known as digital divide, however has been identified as one of the major obstacles to the implementation of e-government system. As digital divide inhibits citizen’s acceptance to e-government, it should be overcome despite the lack of deep theoretical understanding on this issue. This research aimed to investigate the digital divide and its direct impact on e-government system success of local governments in Indonesia as well as indirect impact through the mediation role of trust. In order to get a comprehensive understanding of digital divide, this study introduced a new type of digital divide, the innovativeness divide.

The research problems were approached by applying two-stage sequential mixed method research approach comprising of both qualitative and quantitative studies. In the first phase, an initial research model was proposed based on a literature review. Semi-structured interview with 12 users of e-government systems was then conducted to explore and enhance this initial research model. Data collected in this phase were analyzed with a two-stage content analysis approach and the initial model was then amended based on the findings. As a result, a comprehensive research model with 16 hypotheses was proposed for examination in the second phase.

In the second phase, quantitative method was applied. A questionnaire was developed based on findings in the first phase. A pilot study was conducted to refine the questionnaire, which was then distributed in a national survey resulting in 237 useable responses. Data collected in this phase were analyzed using Partial Least Square based Structural Equation Modeling.

The results of quantitative analysis confirmed 13 hypotheses. All direct influences of the variables of digital divide on e-government system success were supported. The mediating effects of trust in e-government in the relationship between capability divide and e-government system success as well as in the relationship between innovativeness divide and e-government system success were supported, but was rejected in the relationship between access divide and e-government system success. Furthermore, the results supported the moderating effects of demographic variables of age, residential place, and education.

This research has both theoretical and practical contributions. The study contributes to the developments of literature on digital divide and e-government by providing a more comprehensive framework, and also to the implementation of e-government by local governments and the improvement of e-government Readiness Index of Indonesia.

Details

E-Services Adoption: Processes by Firms in Developing Nations
Type: Book
ISBN: 978-1-78560-325-9

Keywords

Book part
Publication date: 4 November 2021

Vasileios Vlachos and Aristidis Bitzenis

Greece's slow recovery from the severe economic depression caused by the great global financial and economic crisis that erupted in late 2000s was interrupted by the effects of…

Abstract

Greece's slow recovery from the severe economic depression caused by the great global financial and economic crisis that erupted in late 2000s was interrupted by the effects of COVID-19 pandemic on economic activity. This chapter looks into the factors shaping Greece's competitive position and discusses the potential to achieve a V-shaped recovery at the end of the pandemic.

Details

Modeling Economic Growth in Contemporary Greece
Type: Book
ISBN: 978-1-80071-123-5

Keywords

Content available
Book part
Publication date: 14 December 2023

Abstract

Details

Digitisation, AI and Algorithms in African Journalism and Media Contexts
Type: Book
ISBN: 978-1-80455-135-6

Open Access
Article
Publication date: 23 January 2023

Md.Tanvir Ahmed, Hridi Juberi, A.B.M. Mainul Bari, Muhommad Azizur Rahman, Aquib Rahman, Md. Ashfaqur Arefin, Ilias Vlachos and Niaz Quader

This study aims to investigate the effect of vibration on ceramic tools under dry cutting conditions and find the optimum cutting condition for the hardened steel machining…

1154

Abstract

Purpose

This study aims to investigate the effect of vibration on ceramic tools under dry cutting conditions and find the optimum cutting condition for the hardened steel machining process in a computer numerical control (CNC) lathe machine.

Design/methodology/approach

In this research, an integrated fuzzy TOPSIS-based Taguchi L9 optimization model has been applied for the multi-objective optimization (MOO) of the hard-turning responses. Additionally, the effect of vibration on the ceramic tool wear was investigated using Analysis of Variance (ANOVA) and Fast Fourier Transform (FFT).

Findings

The optimum cutting conditions for the multi-objective responses were obtained at 98 m/min cutting speed, 0.1 mm/rev feed rate and 0.2 mm depth of cut. According to the ANOVA of the input cutting parameters with respect to response variables, feed rate has the most significant impact (53.79%) on the control of response variables. From the vibration analysis, the feed rate, with a contribution of 34.74%, was shown to be the most significant process parameter influencing excessive vibration and consequent tool wear.

Research limitations/implications

The MOO of response parameters at the optimum cutting parameter settings can significantly improve productivity in the dry turning of hardened steel and control over the input process parameters during machining.

Originality/value

Most studies on optimizing responses in dry hard-turning performed in CNC lathe machines are based on single-objective optimization. Additionally, the effect of vibration on the ceramic tool during MOO of hard-turning has not been studied yet.

Details

International Journal of Industrial Engineering and Operations Management, vol. 5 no. 1
Type: Research Article
ISSN: 2690-6090

Keywords

Book part
Publication date: 15 November 2018

Aristidis Bitzenis and Vasileios Vlachos

A report of the International Labour Organization on undeclared work in Greece refers to failures of formal institutions which contribute to the asymmetry between state and civic…

Abstract

A report of the International Labour Organization on undeclared work in Greece refers to failures of formal institutions which contribute to the asymmetry between state and civic morality. The particular asymmetry is explored through the context of tax morale, which is one of the major determinants of the shadow economy. Although several papers have been published on the Greek shadow economy, tax morale in Greece has not been adequately explored. This research aims to investigate the effect of the economic downturn on the factors determining the level of tax morale through primary data from a European Union-funded research project on the Greek shadow economy. The findings provide policy orientations toward transferring activities from the shadow to the official economy, a goal which is part of Europe 2020 strategy.

Details

Advances in Taxation
Type: Book
ISBN: 978-1-78756-416-9

Keywords

1 – 10 of over 1000