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The kinetic and isotherm studies of gas-solid system were represented by oil palm mesocarp bio-char as adsorbent and formaldehyde as adsorbate. Three kinetic model; i.e pseudo-first-order, pseudo-second-order and Elovich model and three isotherm model; i.e. Langmuir, Freundlich and Temkin isotherm were applied to evaluate the applicability of the equilibrium experimental data and the pyrolysis effect was studied. As a result, oil palm fiber carbonized at 500 °C and 700 °C was best presented by the Langmuir isotherm and oil palm mesocarp carbonized at 600 °C and 800 °C followed Temkin and Freundlich model, respectively. The formaldehyde adsorption was found favorable to happen at 25 °C with initial concentration of 0.5 ppm, 0.9 ppm, 0.75 ppm and 2.1 ppm as the Langmuir dimensionless constant, R L gave the value of 0 < R L  < 1. Carbonization temperature of 500 °C, 600 °C, and 700 °C was kinetically presented by pseudo-first-order kinetic equation and carbonization temperature of 800 °C followed Elovich equation. As a conclusion, the pyrolysis of oil palm mesocarp does affect the isotherm and kinetic behavior of formaldehyde adsorption on oil palm char. [ABSTRACT FROM AUTHOR]

Quasi-vertically aligned zinc oxide nanorod (ZnO NR) arrays were synthesized via hydrothermal processing on glass substrates coated with a conductive layer of aluminium-doped zinc oxide (AZO). Different characterization techniques were used to study the phase structures, surface morphology and elemental composition of the prepared nanorods, including X-ray diffraction (XRD), field emission scanning microscopy (FE-SEM) and X-ray photoelectron spectroscopy (XPS). The sensing behaviour of the ZnO NR arrays has been demonstrated toward different concentrations of 2-methoxyethanol solvent, a highly toxic organic compound. The sensitivity of the prepared sensor is 24 nA/(ppm cm-2) and 60 nA/(ppm cm-2) at applied voltages of 5 V and 10 V, respectively. Its limit of detection (LoD) is 190 ± 5 ppm independently of the applied voltage. The mechanism of the sensing behaviour was explained based on the charge-transfer mechanisms. [ABSTRACT FROM AUTHOR]

Abstract: The effect of gamma radiation on the mechanical and structural properties of gold ball bonds was investigated. Gold wires from thermosonic wire bonding were exposed to gamma rays from a Cobalt-60 source at a low dose (5Gy). The load–depth curve of nanoindentation for the irradiated gold wire bond has an apparent staircase shape during loading compared to the as-received sample. The hardness of the specimens calculated from the nanoindentation shows an increase in value from 0.91 to 1.09GPa for specimens after exposure. The reduced elastic modulus for irradiated specimens significantly increased as well, with values from 75.18 to 98.55GPa. The change in intrinsic properties due to gamma radiation was investigated using dual-focused ion beam and high-resolution transmission electron microscope analysis. The dual-focused ion beam and high-resolution transmission electron microscope images confirmed the changes in grain structure and the presence of dislocations. The scanning electron microscope micrographs of focused ion beam cross sections showed that the grain structure of the gold became elongated and smaller after exposure to gamma rays. Meanwhile, high-resolution transmission electron microscopy provided evidence that gamma radiation induced dislocation of the atomic arrangement. [Copyright &y& Elsevier]

Abstract: This paper characterizes die damage resulting from various wafer thinning processes. Die fracture strength is measured using ball breaker test with respect to die surface finish. Further study on surface roughness and topography of each surface finish is obtained by atomic force microscopy (AFM) and scanning electron microscopy (SEM) techniques. Stress relief process with 25μm removal is able to strengthen 100μm wafer by 20.4% using chemical wet etch and 75μm wafer by 36.4% with plasma etch. Relatively, plasma etching shows higher fracture strength and flexibility compared to chemical wet etch. This is due to topography of the finished surface of plasma etch is smoother and rounded, leading to a reduced stress concentration, hence improved fracture strength. [Copyright &y& Elsevier]

Abstract: This paper discusses on the surface characteristics of each of the seven set-up process steps prior completion of under bump metallurgy (UBM) deposition. The Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) techniques were used to obtain the surface roughness and morphology of each deposition process. The elemental analysis using Energy Disperse X-Ray (EDX) and precision micro-cross-section using Focus Ion Beam (FIB) was also used in this study. The first zincation process has high surface roughness but preserved surface morphology of initial thin-film surface. The second zincation provides the improved surface roughness due to the replacement aluminum layer with ion zinc in the solution. Smooth surfaces leads to better shear strength. However, second zincation will affect the Al thickness, hence excessive attacks on Al layer may cause reliability problem. [Copyright &y& Elsevier]

• A method of removing CIGS layers up until MoSe 2 of TFPV using mechanical brushing and scribing was found to be plausible method before ultrasonic bonding application. • Ultrasonic Al bond on Mo back contact layer has higher bondability as compared to that of ultrasonic Al bond on MoSe 2 in terms of electrical (contact resistance) and mechanical (peel strength) performances. • The creation of micro weld between ultrasonic Al bonds with Mo can be identified through the identification of failure modes from load-distance profile of peel test. • Rigidity and stress distribution experienced during lamination process determine the panel construction CIGS TFPV selection. This paper aims to study the bondability of ultrasonic Aluminum, Al bonds on Mo and MoSe 2 layers of back-contact metal of copper indium gallium (de)selenide (CIGS) thin film photovoltaic (TFPV) solar panel. The bondability of ultrasonic Al bonds were evaluated based on the contact resistance, R c , peel strength and electrical characteristics measured using transmission line method (TLM), peel test, and current–voltage (I-V) measurement, respectively. Besides, the qualitative results of load-distance profiles from tensile test also have been used to evaluate the bondability of the ultrasonic Al bonds. Two type of lamination constructions namely construction 1 and construction 2 were built on the CIGS TPFV solar panel with ultrasonic Al bonds on Mo and MoSe 2. It was noted that the new method of removing CIGS layer up until MoSe 2 is the plausible technique to be used. Ultrasonic Al bond on Mo layer has higher bondability as compared to that of ultrasonic Al bond on MoSe 2 through the quantitative results of R c , peel strength and qualitative result of load-distance profile. CIGS TFPV solar panel with construction 2 is the suitable construction for the CIGS TFPV solar panel due to the higher rigidity, and even stress distribution experienced during lamination process as compared to that of construction 1. It is noted that steps taken from ultrasonic bonding until lamination process has increased the cumulative contact area and decreased the R c and consequently increased the efficiency of CIGS TFPV solar panel with ultrasonic Al bond on MoSe 2 layer. [ABSTRACT FROM AUTHOR]

Abstract: This paper describes the behaviour of bioactive wollastonite materials containing Malaysian limestone and silica sand. Wollastonite, which is also known as calcium silicate (CaSiO3), is an industrial mineral composed of calcium, silicon and oxygen. Pseudowollastonite, which is a primary crystal of wollastonite, was synthesised via a solid-state reaction at a temperature of 1450°C. The in-vitro bioactivity of wollastonite was examined by soaking it in simulated body fluid (SBF) solution for 1–7 days at 36.5°C. The soaked wollastonite samples were characterised using XRD, SEM-EDX, FTIR and ICP analyses. Apatite particles precipitated on the surface of the wollastonite sample after the sample was soaked in the SBF. The XRD analysis indicated the presence of an increasing amount of the hydroxyapatite phase as the soaking time increased. The SEM and EDX analyses indicated the formation of granules of agglomerated apatite particles on the surface of the soaked wollastonite sample. During the formation of apatite, phosphate ions from the SBF solution were consumed. This process was confirmed by ICP, which revealed a decrease in ion concentration after the soaking process. The FTIR analysis indicated that the peaks of the phosphate ions increase when the apatite layer forms on the surface of the wollastonite sample. After the soaking process, a calcium deficient hydroxyapatite layer was observed on the wollastonite sample. The study concludes that wollastonite produced from Malaysian limestone and silica sand is bioactive and may be used as an implantable biomaterial. [Copyright &y& Elsevier]

Abstract: ZnO thin films have been successfully synthesized by thermal evaporation of pure zinc at 900°C under the flow of different percentages of argon and oxygen gases. The films were characterized by X-ray diffraction (XRD), variable pressure scanning electron microscopy (VPSEM), energy dispersive X-ray spectroscopy (EDS) and UV–vis spectroscopy. The aim of this paper is to study the influence of the oxygen percentage on the structural and morphological properties of the ZnO films. VPSEM results show that very thick needle structures were produced at high oxygen percentages. EDS results revealed that only Zn and O are present in the sample, indicating a composition of pure ZnO. XRD results showed that the ZnO synthesized under different quantities of oxygen were crystalline with the hexagonal wurtzite structure. UV–vis spectroscopy results indicated that the optical band gap energies from the transmission spectrum are between 3.62 and 3.69eV for ZnO thin films. [Copyright &y& Elsevier]