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Article
Publication date: 24 August 2022

Yanfu Wang, Xin Wang and Lifei Liu

Lapping is a vital flattening process to improve the quality of processed semiconductor wafers such as single-crystal sapphire wafers. This study aims to optimise the…

34

Abstract

Purpose

Lapping is a vital flattening process to improve the quality of processed semiconductor wafers such as single-crystal sapphire wafers. This study aims to optimise the lapping process of the fixed-abrasive lapping plate of sapphire wafers with good overall performance [i.e. high material removal rate (MRR), small surface roughness (Ra) of the wafers after lapping and small lapping plate wear ratio (η)].

Design/methodology/approach

The influence of process parameters such as lapping time, abrasive size, abrasive concentration, lapping pressure and lapping speed on MRR, Ra and η of lapping-processed sapphire wafers was studied, and the results were combined with experimental data to establish a regression model. The multi-evaluation index optimisation problem was transformed into a single-index optimisation problem via an entropy method and the grey relational analysis (GRA) to comprehensively evaluate the performance of each parameter.

Findings

The results revealed that lapping time, abrasive size, abrasive concentration, lapping pressure and lapping speed had different influence degrees on MRR, Ra and η. Among these parameters, lapping time, lapping speed and abrasive size had the most significant effects on MRR, Ra and η, and the established regression equations predicted the response values of MRR, Ra and η to be 99.56%, 99.51% and 93.88% and the relative errors between the predicted and actual measured values were <12%, respectively. With increased lapping time, MRR, Ra and η gradually decreased. With increased abrasive size, MRR increased nearly linearly, whereas Ra and η initially decreased but subsequently increased. With an increase in abrasive concentration, MRR, Ra and η initially increased but subsequently decreased. With increased lapping pressure, MRR and η increased nearly linearly and continuously, whereas Ra decreased nearly linearly and continuously. With increased lapping speed, Ra initially decreased sharply but subsequently increased gradually, whereas η initially increased sharply but subsequently decreased gradually; however, the change in MRR was not significant. Comparing the optimised results obtained via the analysis of influence law, the parameters optimised via the entropy method and GRA were used to obtain sapphire wafers lapping with an MRR of 4.26 µm/min, Ra of 0.141 µm and η of 25.08, and the lapping effect was significantly improved.

Originality/value

Therefore, GRA can provide new ideas for ultra-precision processing and process optimisation of semiconductor materials such as sapphire wafers.

Details

Microelectronics International, vol. 39 no. 4
Type: Research Article
ISSN: 1356-5362

Keywords

Book part
Publication date: 21 October 2013

Ivan-Damir Anic, Milivoj Markovic and Nikola Knego

The purpose of this chapter was to investigate consumer perceptions of retail agglomeration (RA) characteristics in Zagreb region. Perceived RA characteristics were…

Abstract

Purpose

The purpose of this chapter was to investigate consumer perceptions of retail agglomeration (RA) characteristics in Zagreb region. Perceived RA characteristics were compared between two major types of RA: Planned retail agglomerations (PRA) and Evolved retail agglomerations (ERA).

Design/methodology/approach

Data were collected with consumer survey and analyzed using descriptive statistics, exploratory factor analysis and analysis of variance (ANOVA).

Findings

Findings indicate that four factors of RA characteristics can be identified: convenience, accessibility, atmosphere, and image. The shoppers’ ratings indicate the strength and weaknesses of RA, and also the dominant position of PRA as compared to evolved RA.

Originality/value

Results show that there were significant differences in shoppers’ perceptions between Planned and evolved RA in Zagreb region. Shoppers evaluated PRA better than ERA on all four factors. Convenience and atmosphere are the best-rated PRA characteristics. Managerial implications are discussed in the study.

Details

Challenges for the Trade of Central and Southeast Europe
Type: Book
ISBN: 978-1-78190-833-4

Keywords

Abstract

Details

Review of Marketing Research
Type: Book
ISBN: 978-0-85724-726-1

Abstract

Details

Contingent Valuation: A Critical Assessment
Type: Book
ISBN: 978-1-84950-860-5

Book part
Publication date: 17 December 2003

Krina Griva and Nikolaos Vettas

We examine a two-period, homogeneous product duopoly model. Consumers choose the supplier that demands the lowest two-part tariff payment. When per unit rates are given…

Abstract

We examine a two-period, homogeneous product duopoly model. Consumers choose the supplier that demands the lowest two-part tariff payment. When per unit rates are given, firms’ competition in fixed fees leads to an endogenous segmentation of the market, with positive profit for both firms and consumers self-selecting according to their usage levels. Consumers’ usage levels vary between periods but switching suppliers is costly. Examining various possibilities (including price discrimination between old and new customers) reveals that switching affects the two suppliers asymmetrically, as the average usage level of a firm’s clientele changes.

Details

Organizing the New Industrial Economy
Type: Book
ISBN: 978-0-76231-081-4

Abstract

Details

Modelling the Riskiness in Country Risk Ratings
Type: Book
ISBN: 978-0-44451-837-8

Article
Publication date: 5 August 2022

N. Keerthi Reddy and M. Sankar

This study aims to numerically study the buoyant convective flow of two different nanofluids in a porous annular domain. A uniformly heated inner cylinder, cooled outer…

Abstract

Purpose

This study aims to numerically study the buoyant convective flow of two different nanofluids in a porous annular domain. A uniformly heated inner cylinder, cooled outer cylindrical boundary and adiabatic horizontal surfaces are considered because of many industrial applications of this geometry. The analysis also addresses the comparative study of different porous media models governing fluid flow and heat transport.

Design/methodology/approach

The finite difference method has been used in the current simulation work to obtain the numerical solution of coupled partial differential equations. In particular, the alternating direction implicit method is used for solving transient equations, and the successive line over relaxation iterative method is used to solve time-independent equation by choosing an optimum value for relaxation parameter. Simpson’s rule is adopted to estimate average Nusselt number involving numerical integration. Various grid sensitivity checks have been performed to assess the sufficiency of grid size to obtain accurate results. In this analysis, a general porous media model has been considered, and a comparative study between three different models has been investigated.

Findings

Numerical simulations are performed for different combinations of the control parameters and interesting results are obtained. It has been found that the an increase in Darcy and Rayleigh numbers enhances the thermal transport rate and strengthens the nanofluid movement in porous annulus. Also, higher flow circulation rate and thermal transport has been detected for Darcy model as compared to non-Darcy models. Thermal mixing could be enhanced by considering a non-Darcy model.

Research limitations/implications

The present results could be effectively used in many practical applications under the limiting conditions of two-dimensionality and axi-symmetry conditions. The only drawback of the current study is it does not include the three-dimensional effects.

Practical implications

The results could be used as a first-hand information for the design of any thermal systems. This will help the design engineer to have fewer trial-and-run cases for the new design.

Originality/value

A pioneering numerical investigation on the buoyant convective flow of two different nanofluids in an annular porous domain has been carried out by using a general Darcy–Brinkman–Forchheimer model to govern fluid flow in porous matrix. The results obtained from current investigation are novel and original, with numerous practical applications of nanofluid saturated porous annular enclosure in the modern industry.

Details

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

Keywords

Article
Publication date: 23 May 2022

Stefano Baraldi, Antonella Cifalinò, Irene Eleonora Lisi and Marco Giovanni Rizzo

Scholars have recognised that an inherent ambiguity underlines the roles of controllers, as they navigate multiple expectations of various organisational counterparts…

Abstract

Purpose

Scholars have recognised that an inherent ambiguity underlines the roles of controllers, as they navigate multiple expectations of various organisational counterparts, including the control-type needs of corporate top managers and the decision-making needs of business managers. Role ambiguity (RA) is a form of psychological distress leading to dysfunctional work-related outcomes (WROs); therefore, the purpose of this study is to analyse whether the use of performance measurement systems (PMSs) by controllers influences their RA and, in turn, their job satisfaction and organisational commitment.

Design/methodology/approach

This study used data collected from a survey of 158 controllers to investigate whether controllers’ diagnostic and interactive uses of PMSs affect their RA and, indirectly, organisational commitment and job satisfaction.

Findings

The results show that an interactive use of PMSs by controllers decreases their RA, with positive effects on their commitment and satisfaction. On the contrary, PMS diagnostic use has no significant influence on either RA or WROs.

Originality/Value

This study contributes to the body of literature on the psychological effects of PMSs related to RA, providing further empirical evidence to suggest that the adoption of PMSs may decrease individuals’ RA and, in turn, increase their WROs. In particular, this study enriches the existing literature with two elements of novelty: focus on controllers’ role instead of that of popular managers and focus on the behavioural effects of the diagnostic and interactive uses of PMSs.

Details

Journal of Accounting & Organizational Change, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1832-5912

Keywords

Article
Publication date: 4 March 2021

Mohan Prasath Mani and Saravana Kumar Jaganathan

This study aims to fabricate an electrospun scaffold by combining radish (Ra) and cerium oxide (CeO2) into a polyurethane (PU) matrix through electrospinning and…

Abstract

Purpose

This study aims to fabricate an electrospun scaffold by combining radish (Ra) and cerium oxide (CeO2) into a polyurethane (PU) matrix through electrospinning and investigate its feasibility for cardiac applications.

Design/methodology/approach

Physicochemical properties were analysed through various characterization techniques such as scanning electron microscopy (SEM), Fourier transforms infrared transforms analysis (FTIR), contact angle measurements, thermal analysis, atomic force microscopy (AFM) and mechanical testing. Further, blood compatibility assessments were carried out through activated partial thromboplastin time (APTT) and prothrombin time (PT) and hemolysis assay to evaluate the anticoagulant nature.

Findings

PU/Ra and PU/Ra/CeO2 exhibited a smaller fibre diameter than PU. Ra and CeO2 were intercalated in the polyurethane matrix which was evidenced in the infrared analysis by hydrogen bond formation. PU/Ra composite exhibited hydrophilic nature whereas PU/Ra/CeO2 composite turned hydrophobic. Surface measurements depicted the lowered surface roughness for the PU/Ra and PU/Ra/CeO2 compared to the pristine PU. PU/Ra and PU/Ra/CeO2 displayed enhanced degradation rates and improved mechanical strength than the pristine PU. The blood compatibility assay showed that the PU/Ra and PU/Ra/CeO2 had delayed blood coagulation times and rendered less toxicity against red blood cells (RBC’s) than PU.

Originality/value

This is the first report on the use of radish/cerium oxide in cardiac applications. The developed composite (PU/Ra and PU/Ra/CeO2) with enhanced mechanical and anticoagulant nature will serve as an indisputable candidate for cardiac tissue regeneration.

Details

Pigment & Resin Technology, vol. 51 no. 1
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 24 May 2021

Tao Liu, Weiquan Wang, Jingjun (David) Xu, Donghong Ding and Honglin Deng

This paper investigates the effects of advising strength of a recommendation agent on users' trust and distrust beliefs and how the effects are moderated by perceived…

Abstract

Purpose

This paper investigates the effects of advising strength of a recommendation agent on users' trust and distrust beliefs and how the effects are moderated by perceived brand familiarity.

Design/methodology/approach

A research model is evaluated using a laboratory experiment with 149 participants.

Findings

Results reveal that a strong advising tone leads to higher trust in terms of users' credibility and benevolence beliefs and lower distrust in terms of their discredibility beliefs (the trustor's concerns regarding the trustee's dishonesty and competence in engaging in harmful behavior) when perceived brand familiarity is high. By contrast, when brand familiarity is low, strong advising tone results in low trust in terms of users' credibility belief and high distrust in terms of their beliefs in discredibility and malevolence (concerns regarding the trustee's conduct in terms of a malicious intention that can hurt the trustor's welfare).

Originality/value

This paper contributes to the trust and distrust literature by studying how each of the dimensions of trust and distrust can be affected by an RA's design feature. It extends the attribution theory to the RA context by studying the moderating role of brand familiarity in determining the effects of the advising strength of an RA. It provides actionable guidelines for practitioners regarding the adoption of an RA's appropriate advising strength to promote different types of products.

Details

Information Technology & People, vol. 34 no. 7
Type: Research Article
ISSN: 0959-3845

Keywords

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