Zainal Ariffin Ahmad

Use of waste gypsum to replace natural gypsum as set retarders in portland cement

The present study is focused on clarifying the influence of waste gypsum (WG) in replacing natural gypsum (NG) in the production of ordinary Portland cement (OPC). WG taken from slip casting moulds in a ceramic factory was formed from the hydration of plaster of paris. Clinker and 3-5wt% of WG was ground in a laboratory ball mill to produce cement waste gypsum (CMWG). The same procedure was repeated with NG to substitute WG to prepare cement natural gypsum (CMNG). The properties of NG and WG were investigated via X-ray Diffraction (XRD), X-ray fluorescence (XRF) and differential scanning calorimetry (DSC)/thermogravimetric (TG) to evaluate the properties of CMNG and CMWG. The mechanical properties of cement were tested in terms of setting time, flexural and compressive strength. The XRD result of NG revealed the presence of dihydrate while WG contained dihydrate and hemihydrate. The content of dihydrate and hemihydrates were obtained via DSC/TG, and the results showed that WG and NG contained 12.45% and 1.61% of hemihydrate, respectively. Furthermore, CMWG was found to set faster than CMNG, an average of 15.29% and 13.67% faster for the initial and final setting times, respectively. This was due to the presence of hemihydrate in WG. However, the values obtained for flexural and compressive strength were relatively the same for CMNG and CMWG. Therefore, this result provides evidence that WG can be used as an alternative material to NG in the production of OPC.

Team learning, top management support and new product development success

Purpose – This paper aims to investigate the relationship between team learning, top management support (TMS) and new product development (NPD) success.Design/methodology/approach – This is a quantitative research by nature. A questionnaire derived from previous studies and covered by 27 NPD projects in the high‐tech semiconductor industry in Malaysia. Stepwise regression was adopted to test hypothesis.Findings – Out of the four independent variables, knowledge acquisition and information interpretation were found to have a signification relationship with NPD success. The findings also confirmed that TMS is a moderator in the relationship between team learning and NPD success.Research limitations/implications – The relationships investigated in this research deserve further investigation. Because the data analyzed were collected from the high‐tech semiconductor industry in Malaysia. More studies are required before general conclusion can be drawn.Practical implications – It is reasonable to conclude, on t...

Effect of Sintering Temperatures on Sr-Doped NiO Ceramics

Sr - doped NiO ceramic was prepared using solid state method. The calcination temperature used at 950 oC for 4 hours and the sintering temperatures was varied from 1100 to 1300 oC for 3 hours. The results depict the microstructures increasing in grains size (1-8 μm) by increase of sintering temperatures. The density and porosity testing support the result of microstructures analysis. The larger grains size induced the increase in density and lower in porosity. The dielectric properties is observed in a wide frequency range of (1 - 1 000 MHz). The increase of dielectric constant is associated with the decrease of dielectric loss. The optimum sintering temperature was obtained at 1200 oC depict the grain size range (1 - 2 μm) with highest dielectric constant (1.61 x 103) and lowest dielectric loss (1.15) at 1MHz.

A novel multi-band dual-segment rectangular Dielectric Resonator Antenna

Modern wireless communication devices demands for multiband operation using single antenna to reduce complexity of the system. In this work a multi-band rectangular shaped Dielectric Resonator Antenna (DRA) is designed and analyzed. A two segments rectangular dielectric resonator with different permittivitys are stacked together, and a notch is created in the top segment of the resonator. By optimizing notch value and position of rectangular Dielectric Resonator (DR) over the microstrip feed line multi-band operation of the antenna is achieved. Parametric study of the antenna is done so as to achieve optimum performance of the antenna in both operating bands. The lower operating frequency band of the antenna gives approximately 14 % (5.3 GHz to 6.1 GHz) impedance bandwidth, whereas upper operating frequency band of the antenna yields almost 8 % (7.2 GHz to 7.8 GHz) impedance bandwidth. Simulation of the proposed antenna is performed using Computer Simulation Technology (CST 2014). Return loss of the antenna is measured using Agilent Technology PNA N5245A network analyzer. A close agreement between simulation and measured results is obtained.

Mixing Optimization of Sn-Cu-Si3N4 via Powder Metallurgy Route for Composite Solder Fabrication

The aim of this study was to optimize the mixing process of a composite solder fabricated via powder metallurgy route, before details study were conducted in the next stage. Powder of Sn, Cu and Si3N4 were carefully weighted, mixed and blended in a mechanical alloying machine. The speed of rotation for the jar was kept constant while the time of mixing was varied. Si3N4 were added to the Sn-0.7Cu solder as reinforcement. Upon completion of mixing process, the mixed powders were later compacted into a thin disc. The compacted samples were then sintered in a horizontal tube furnace. Microstructural examinations by using SEM were conducted in order to analyze the distribution of Cu and Si3N4 particles. With the assistance of ImageJ software, average particle distributions were calculated. Results showed that the best particle distributions were achieved when the mixed powder were blended for 6 hours.

Compaction Optimization of Sn-Cu-Si3N4 via Powder Metallurgy Route for Composite Solder Fabrication

The aim of this study was to optimize the compaction process of a composite solder fabricated via powder metallurgy route, before details study were conducted in the next stage. Powder of Sn, Cu and Si3N4 were carefully weighted, mixed and blended in a mechanical alloying machine. Si3N4 were added to the Sn-0.7Cu solder as reinforcement.After 6 hours of mixing and blending, the powders were later compacted into a thin disc at 5 different pressures. Densities and volumes of the compacted samples were then obtained by using MicromeriticsAccuPyc II 1340 Gas Pycnometer. All data were analyzed and compared with each other in order to select the best parameter for compaction pressure. Results showed that at 140 bars, the porosity percentage is the lowest. Hence, it was decided that 140 bars is the best parameter for compaction process.

Solder microstructure and intermetallic interface evaluation between Sn-3.5Ag-1.0Cu-xNi lead free solder under long time thermal aging (x: 0, 0.05, 0.2, 0.5)

Sn-3.5Ag-1.0Cu-xNi (x: 0, 0.05, 0.2, 0.5) solder alloy has been developed to improve properties and microstructure of Sn-3.5Ag-1.0Cu based solder. The composite solder were synthesized via the powder metallurgy route which consist of blending, compacting and sintering process. The sintered solders were characterized for it melting temperature, SEM-EDX analysis was done to confirm the homogeneity of sample element distribution and X-Ray diffraction (XRD) analysis was conducted to see the presents of some phases. XRD analysis of sintered sample showed the presents of Ni3Sn4 and Ni3Sn2 phases. Solders were melted on copper substrate at 250°C for one minute on hot plate and aged at 150°C from 0 to 400 hours. The microstructure of the solder and the growth of IMC formation were studied under Scanning Electron Microscope (SEM) and EDX. The phases formed were studied under SEM-EDX. The SEM results show the presence of Cu6Sn5, Cu3Sn and Ag3Sn intermetallic in the Sn-3.5Ag-1.0Cu solder and Sn-3.5Ag-1.0Cu-xNi solder.

Intermetallic evolution between Sn-3.5Ag-1.0Cu-xZn lead free solder and copper substrate under long time thermal aging (x: 0, 0.1, 0.4, 0.7)

Due to environmental concern regarding toxicity of lead-based solder, the lead-free solders were introduced as a replacing solder in microelectronics devices technology. In this study, the effects of 0.1, 0.4 and 0.7 wt% Zn additions on the intermetallic formation and thickness of Sn-3.5Ag-1.0Cu solder on Cu substrate after long time aging were investigated. The X-Ray Diffraction (XRD) analysis shown that there were Cu6Sn5, Cu3Sn, β-Sn, CuZn and Ag3Sn phase formed after sintering process. The morphology of the intermetallic was observed under Scanning Electron Microscope (SEM) and the elemental distribution was confirmed by Energy Dispersive X-ray (EDX). The intermetallic thickness increases as the aging temperature increases while the addition of zinc into the system has suppressed the intermetallic formation.

Leading innovation: A matter of style

A recent Malaysian Innovation Climate Survey (MICS) suggests that whereas organizational leaders play a crucial role in inculcating innovation, they are seen as inhibitors to innovation due to their unwillingness to take risk, risk adversity and lack of clear direction. To lead innovation in their organizations, Malaysian SMEs leaders and entrepreneurs need to understand that their leadership style may influence innovation by creating an organizational environment where innovation thrives. This paper proposes a framework for managers and leaders to identify the appropriate leadership style(s) for championing and influencing innovation in their organizations. (92 words).

The makings of knowledge enterprises in Malaysia

The knowledge management (KM) discipline conjures a host of understanding and impact upon the global business community albeit commercially or socially. Regardless of the different approach to KM, it has inarguably brought about changes in viewing the knowledge capabilities and capacities of organisations. Skyrme (1998) argued that knowledge has become the key economic resource and the only source of competitive advantage. Hence organisational learning is an integral part of KM initiatives and has been widely practiced in many large organisations and across nations such as Europe, North America and Asia Pacific. Thus, this paper explores the KM initiatives of government link companies (GLCs) in Malaysia via synergising on knowledge strategy and its resource capabilities in order to achieve competitive advantage.