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Article
Publication date: 2 August 2021

Nur Atiqah Hamzah, Mohd Anas Ahmad, Rahil Izzati Mohd Asri, Ezzah Azimah Alias, Mohd Ann Amirul Zulffiqal Md Sahar, Ng Sha Shiong and Zainuriah Hassan

The purpose of this paper is to enhance the efficiency of the LED by introducing three-step magnesium (Mg) doping profile. Attention was paid to the effects of the Mg…

Abstract

Purpose

The purpose of this paper is to enhance the efficiency of the LED by introducing three-step magnesium (Mg) doping profile. Attention was paid to the effects of the Mg doping concentration of the first p-GaN layer (i.e. layer close to the active region). Attention was paid to the effects of the Mg doping concentration of the first p-GaN layer (i.e. layer close to the active region).

Design/methodology/approach

Indium gallium nitride (InGaN)–based light-emitting diode (LED) was grown on a 4-inch c-plane patterned sapphire substrate using metal organic chemical vapor deposition. The Cp2Mg flow rates for the second and third p-GaN layers were set at 50 sccm and 325 sccm, respectively. For the first p-GaN layer, the Cp2Mg flow rate varied from 150 sccm to 300 sccm to achieve different Mg dopant concentrations.

Findings

The full width at half maximum (FWHM) for the GaN (102) plane increases with increasing Cp2Mg flow rate. FWHM for the sample with 150, 250 and 300 sccm Cp2Mg flow rates was 233 arcsec, 236 arcsec and 245 arcsec, respectively. This result indicates that the edge and mixed dislocations in the p-GaN layer were increased with increasing Cp2Mg flow rate. Atomic force microscopy (AFM) results reveal that the sample grown with 300 sccm exhibits the highest surface roughness, followed by 150 sccm and 250 sccm. The surface roughness of these samples is 2.40 nm, 2.12 nm and 2.08 nm, respectively. Simultaneously, the photoluminescence (PL) spectrum of the 250 sccm sample shows the highest band edge intensity over the yellow band ratio compared to that of other samples. The light output power measurements found that the sample with 250 sccm exhibits high output power because of sufficient hole injection toward the active region.

Originality/value

Through this study, the three steps of the Mg profile on the p-GaN layer were proposed to show high-efficiency InGaN-based LED. The optimal Mg concentration was studied on the first p-GaN layer (i.e. layer close to active region) to improve the LED performance by varying the Cp2Mg flow rate. This finding was in line with the result of PL and AFM results when the samples with 250 sccm have the highest Mg acceptor and good surface quality of the p-GaN layer. It can be deduced that the first p-GaN layer doping has a significant effect on the crystalline quality, surface roughness and light emission properties of the LED epi structure.

Details

Microelectronics International, vol. 38 no. 3
Type: Research Article
ISSN: 1356-5362

Keywords

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Article
Publication date: 5 September 2021

Nur Shahira Abdul Nasir, Revathy Deivasigamani, Muhammad Khairulanwar Abdul Rahim, Siti Nur Ashakirin Mohd Nashruddin, Azrul Azlan Hamzah, M. Farhanulhakim M. Razip Wee and Muhamad Ramdzan Buyong

The purpose of this paper is to visualize protein manipulation using dielectrophoresis (DEP) as a substantial perspective on being an effective protein analysis and…

Abstract

Purpose

The purpose of this paper is to visualize protein manipulation using dielectrophoresis (DEP) as a substantial perspective on being an effective protein analysis and biosensor method as DEP is able to be used as a means for manipulation, fractionation, pre-concentration and separation. This research aims to quantify DEP using an electrochemical technique known as cyclic voltammetry (CV), as albumin is non-visible without any fluorescent probe or dye.

Design/methodology/approach

The principles of DEP were generated by an electric field on tapered DEP microelectrodes. The principle of CV was analysed using different concentrations of albumin on a screen-printed carbon electrode. Using preliminary data from both DEP and CV methods as a future prospect for the integration of both techniques to do electrical quantification of DEP forces.

Findings

The size of the albumin is known to be 0.027 µm. Engineered polystyrene particle of size 0.05 µm was selected to mimic the DEP actuation of albumin. Positive DEP of the sample engineered polystyrene particle was able to be visualized clearly at 10 MHz supplied with 20 Vpp. However, negative DEP was not able to be visualized because of the limitation of the apparatus. However, albumin was not able to be visualized under the fluorescent microscope because of its translucent properties. Thus, a method of electrical quantification known as the CV technique is used. The detection of bovine serum albumin (BSA) using the CV method is successful. As the concentration of BSA increases, the peak current obtained from the voltammogram decreases. The peak current can be an indicator of DEP response as it correlates to the adsorption of the protein onto the electrodes. The importance of the results from both CV and DEP shows that the integration of both techniques is possible.

Originality/value

The integration of both methods could give rise to a new technique with precision to be implemented into the dialyzers used in renal haemodialysis treatment for manipulation and sensing of protein albumin.

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Article
Publication date: 4 March 2021

Harun Zontul, Hudhaifa Hamzah and Besir Sahin

This paper aims to exhibit a numerical study to analyze the influence of a periodic magnetic source on free convection flow and entropy generation of a ferrofluid in a

Abstract

Purpose

This paper aims to exhibit a numerical study to analyze the influence of a periodic magnetic source on free convection flow and entropy generation of a ferrofluid in a baffled cavity. In this study, ferrofluid nanofluid was selected due to its ability to image magnetic domain structures within the cavity. The non-uniform magnetic source is considered as a sinusoidal distribution in the vertical direction.

Design/methodology/approach

The finite volume technique is used to evaluate the steady two-dimensional partial differential equations that govern the flow with its corresponding boundary conditions.

Findings

The obtained results indicate that a significant increase in the average Nusselt number can be achieved with the use of the periodic magnetic source instead of a uniform case. In addition, the effectiveness of the adiabatic baffle notably depends on its position and Rayleigh number. Regardless of the values of period and Hartmann numbers, the periodic magnetic source has a higher entropy generation and lower Bejan number than the uniform magnetic source.

Originality/value

The novelty of this research lies in applying a periodic magnetic source on the natural convection of ferrofluids in a baffled cavity.

Details

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

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Article
Publication date: 1 June 1996

A. Hamzah and M. Zairi

As the first of a series of three papers looking at best practice in people management, reports on a comprehensive study which was carried out by benchmarking five…

Abstract

As the first of a series of three papers looking at best practice in people management, reports on a comprehensive study which was carried out by benchmarking five organizations representing the fast‐moving consumer goods sector, and the service and retail services sectors, using a methodology based on an adaptation of the European Quality Award model. Benchmarks five winners of prestigious quality awards using secondary data derived from award submission documents. Makes use of various comparisons in order to derive best practices and also to discuss critical factors in the area of people management. Discusses the primary data analysis of the five organizations studied, representing Elida Gibbs Ltd, the Nationwide Building Society, Post Office Counters Ltd, Birds Eye Walls and Natwest Bank.

Details

Training for Quality, vol. 4 no. 2
Type: Research Article
ISSN: 0968-4875

Keywords

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Article
Publication date: 23 September 2020

Muhamad Ramdzan Buyong, Farhad Larki, Muhamad Ikhmal Hakimi Zainal, Abdelaziz Yousif Ahmed Almahi, Ahmad Ghadafi Ismail, Azrul Azlan Hamzah, Aminuddin Ahmad Kayani Kayani, Céline Elie Caille and Burhanuddin Yeop Majlis

This paper aims to present the capacitance characterization of tapered dielectrophoresis (DEP) microelectrodes as micro-electro-mechanical system sensor and actuator…

Abstract

Purpose

This paper aims to present the capacitance characterization of tapered dielectrophoresis (DEP) microelectrodes as micro-electro-mechanical system sensor and actuator device. The application of DEP-on-a-chip (DOC) can be used to evaluate and correlate the capacitive sensing measurement at an actual position and end station of liquid suspended targeted particles by DEP force actuator manipulation.

Design/methodology/approach

The capability of both, sensing and manipulation was analysed based on capacitance changes corresponding to the particle positioning and stationing of the targeted particles at regions of interest. The mechanisms of DEP sensor and actuator, designed in DOC applications were energized by electric field of tapered DEP microelectrodes. The actual DEP forces behaviour has been also studied via quantitative analysis of capacitance measurement value and its correlation with qualitative analysis of positioning and stationing of targeted particles.

Findings

The significance of the present work is the ability of using tapered DEP microelectrodes in a closed mode system to simultaneously sense and vary the magnitude of manipulation.

Originality/value

The integration of DOC platform for contactless electrical-driven with selective detection and rapid manipulation can provide better efficiency in in situ selective biosensors or bio-detection and rapid bio-manipulation for DOC diagnostic and prognostic devices.

Details

Microelectronics International, vol. 37 no. 4
Type: Research Article
ISSN: 1356-5362

Keywords

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Article
Publication date: 4 September 2020

Muhamad Ramdzan Buyong, Farhad Larki, Celine Elie Caille, Norazreen Abd Aziz, Ahamad Ghadafi Ismail, Azrul Azlan Hamzah and Burhanuddin Yeop Majlis

This paper aims to present the dielectrophoresis (DEP) force (FDEP), defined as microelectrofluidics mechanism capabilities in performing selective detection and rapid…

Abstract

Purpose

This paper aims to present the dielectrophoresis (DEP) force (FDEP), defined as microelectrofluidics mechanism capabilities in performing selective detection and rapid manipulation of blood components such as red blood cells (RBC) and platelets. The purpose of this investigation is to understand FDEP correlation to the variation of dynamic dielectric properties of cells under an applied voltage bias.

Design/methodology/approach

In this paper, tapered design DEP microelectrodes are used and explained. To perform the characterization and optimization by analysing the DEP polarization factor, the change in dynamic dielectric properties of blood components are observed according to the crossover frequency (fxo) and adjustment frequency (fadj) variation for selective detection and rapid manipulation.

Findings

Experimental observation of dynamic dielectric properties change shows clear correlation to DEP polarization factor when performing selective detection and rapid manipulation. These tapered DEP microelectrodes demonstrate an in situ DEP patterning efficiency more than 95%.

Research limitations/implications

The capabilities of tapered DEP microelectrode devices are introduced in this paper. However, they are not yet mature in medical research studies for various purposes such as identifying cells and bio-molecules for detection, isolation and manipulation application. This is because of biological property variations that require further DEP characterization and optimization.

Practical implications

The introduction of microelectrofluidics using DEP microelectrodes operate by selective detecting and rapid manipulating via lateral and vertical forces. This can be implemented on precision health-care development for lab-on-a-chip application in microfluidic diagnostic and prognostic devices.

Originality/value

This study introduces a new concept to understand the dynamic dielectric properties change. This is useful for rapid, label free and precise methods to conduct selective detection and rapid manipulation of mixtures of RBC and platelets. Further, potential applications that can be considered are for protein, toxin, cancer cell and bacteria detections and manipulation. Implementation of tapered DEP microelectrodes can be used based on the understanding of dynamic dielectric properties of polarization factor analysis.

Details

Microelectronics International, vol. 37 no. 4
Type: Research Article
ISSN: 1356-5362

Keywords

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Article
Publication date: 1 December 1996

A. Hamzah and M. Zairi

Presents the final paper in a series of three, looking at best practice in people management. Papers I and II discussed best practice through direct primary examination…

Abstract

Presents the final paper in a series of three, looking at best practice in people management. Papers I and II discussed best practice through direct primary examination and the scrutiny of secondary data sources, respectively. The examinations represented a group of organizations well experienced with the implementation of total quality management and, in the case of part II, the five organizations studied were all winners of prestigious quality awards. Presents critical areas for effective people management, in many instances supported by the findings of other studies. Also presents evidence of best practice as highlighted by this study and discussed in the earlier papers.

Details

Training for Quality, vol. 4 no. 4
Type: Research Article
ISSN: 0968-4875

Keywords

Content available
Article
Publication date: 12 November 2019

Nurul Afiqah Zulkifly, Maimunah Ismail and Siti Raba’ah Hamzah

The purpose of this paper is to investigate the influences of cultural intelligence, feedback-seeking behavior and shared vision as a mediator on bi-directional knowledge…

Abstract

Purpose

The purpose of this paper is to investigate the influences of cultural intelligence, feedback-seeking behavior and shared vision as a mediator on bi-directional knowledge transfer involving expatriates and host country nationals (HCNs).

Design/methodology/approach

This paper integrates the signaling theory, the social capital theory and the anxiety and uncertainty theory in investigating the relationships between predictors and knowledge transfer in a bi-directional manner. The participants of the study were 125 expatriate-HCN pairs of MNCs and local organizations in the areas of Klang Valley, Malaysia.

Findings

Shared vision was found to significantly mediate the influences of cultural intelligence and feedback-seeking behavior on knowledge transfer as perceived by the respective respondents.

Originality/value

Co-existence between expatriates and HCNs leads to many organizational outcomes including knowledge transfer. This paper additionally provides theoretical and practical implications to human resource practices.

Details

European Journal of Management and Business Economics, vol. 29 no. 2
Type: Research Article
ISSN: 2444-8494

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Article
Publication date: 5 January 2015

Norihan Abdul Hamid, J. Yunas, B. Yeop Majlis, A.A. Hamzah and B. Bais

The purpose of this paper is to discuss the fabrication technology and test of thermo-pneumatic actuator utilizing Si3N4-polyimide thin film membrane. Thin film polyimide…

Abstract

Purpose

The purpose of this paper is to discuss the fabrication technology and test of thermo-pneumatic actuator utilizing Si3N4-polyimide thin film membrane. Thin film polyimide membrane capped with Si3N4 thin layer is used as actuator membrane which is able to deform through thermal forces inside an isolated chamber. The fabricated membrane will be suitable for thermo-pneumatic-based membrane actuation for lab-on-chip application.

Design/methodology/approach

The actuator device consisting of a micro-heater, a Si-based micro-chamber and a heat-sensitive square-shaped membrane is fabricated using surface and bulk-micromachining process, with an additional adhesive bonding process. The polyimide membrane is capped with a thin silicon nitride layer that is fabricated by using etch stop technique and spin coating.

Findings

The deformation property of the membrane depend on the volumetric expansion of air particles in the heat chamber as a result of temperature increase generated from the micro-heater inside the chamber. Preliminary testing showed that the fabricated micro-heater has the capability to generate heat in the chamber with a temperature increase of 18.8 °C/min. Analysis on membrane deflection against temperature increase showed that heat-sensitive thin polyimide membrane can perform the deflection up to 65 μm for a temperature increase of 57°C.

Originality/value

The dual layer polyimide capped with Si3N4 was used as the membrane material. The nitride layer allowed the polyimide membrane for working at extreme heat condition. The process technique is simple implementing standard micro-electro-mechanical systems process.

Details

Microelectronics International, vol. 32 no. 1
Type: Research Article
ISSN: 1356-5362

Keywords

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Article
Publication date: 17 February 2012

Aini Aman, Noradiva Hamzah, Rozita Amiruddin and Ruhanita Maelah

Finance and accounting (FA) offshore outsourcing is a growing trend involving a relocation of business processes to Asia but only few studies focus on understanding the…

Abstract

Purpose

Finance and accounting (FA) offshore outsourcing is a growing trend involving a relocation of business processes to Asia but only few studies focus on understanding the issues that underlie the relocation of FA services. This paper aims to provide understanding of transaction costs economics (TCE) issues in FA offshore outsourcing using a case study of the Malaysia outsourcing industry which is growing and experiencing significant change.

Design/methodology/approach

This study uses a qualitative case study approach. Interviews cover several foreign firms, which are based in Malaysia and involved in FA offshore outsourcing services worldwide. Interviews also include related regulatory bodies in Malaysia.

Findings

Using TCE and management control theoretical framework, findings indicate issues and challenges faced by the firms and the need for contract management skills to mitigate the issues.

Research limitations/implications

This study is limited to a broad discussion of FA offshore outsourcing, TCE and contract management but it could be a basis for future studies on specific issues of managing attrition in FA offshore outsourcing. This study contributes to prior works in TCE and FA offshore outsourcing by establishing controls to minimise costs at contact, contract and control stage. Specifically, this study emphasises contract management such as negotiating contract and using long‐term contractual arrangement.

Practical implications

This study not only identifies TCE issues in offshore FA outsourcing, but also provides suggestions for minimising transaction costs. For example, firms should consider the type of transaction costs involved and plan for appropriate contract management to mitigate the costs.

Originality/value

There is no study yet that discusses in‐depth the issues of TCE in FA offshore outsourcing especially in Malaysia and the need for contract management in mitigating such issues.

Details

Strategic Outsourcing: An International Journal, vol. 5 no. 1
Type: Research Article
ISSN: 1753-8297

Keywords

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