Evolving Malaysia

Towards the end of the 12th century, while Western Europe was still wavering between a dying Roman influence and a dawning Gothicism, preliminaries to a medieval era which would make possible the development of a worldwide humanism, Asia had already lived through her classical period and, sinking into decay, was preparing to face a long period of political and spiritual unrest

Loji nuklear pembekal utama tenaga dunia masa depan

Discussing the relevancy of nuclear power plant

A secondary, coplanar design Ni/MCM-41/Zn microbattery

A secondary Ni/Zn microbattery (200 µm thick) has been developed in a coplanar electrode configuration. The cell is essentially of a circular shape (30 mm in diameter) consisting of a fine circular ring (cathode) and a circle (anode) split apart (~800 µm). Unlike the stacking cell architecture, coplanar configuration offers simple design, ease of fabrication and eventually cost saving. The use of MCM-41 mesoporous silica as the membrane separator cum electrolyte reservoir enables the successful implementation of coplanar configuration. The fabrication of Ni/Zn microbattery first begins with electrodeposition of zinc (Zn) and nickel hydroxide (Ni(OH)2) thin films onto patterned FR4 printed circuit board, followed by deposition of zinc oxide (ZnO) slurry onto the zinc active layer, and finally ends by multiple drop-coating procedures of MCM-41 from its precursor solution at ambient temperature. Once a potassium hydroxide (6 M KOH)/MCM-41 electrolyte-separator mixture is incorporated, the cell is sealed with an acrylic sheet and epoxy adhesive. The fabricated microbatteries were capable to sustain around 130 deep charge-discharge cycles. When rated at 0.1 mA, the energy density of the microbattery was around 3.82 Wh l-1 which is suitable for low rate applications and storage for micro energy harvesters such as piezoelectric generators

Observation on void formed in oxide scale of Fe-Cr-Ni alloy at 1073K in dry and humid environments

Void formation in oxide scale during high temperature oxidation is a common phenomenon. Over a long period of time voids will affect the mechanical property of scales by influencing the cracking and spalling. Voids formed in dry environment are different than that of formed in humid environment. With the presence of water vapor in humid environment the formation of void will increase, thus greater number of void compared to that in dry environment. Fe-Cr-Ni alloy samples were exposed isothermally at 1073 K in air (P_(O_2)= 0.21atm = 2.1 x? 10 5 Pa) and humid (air + steam) environments. XRD analysis done to all samples confirms that Fe2O3, Fe3O4, NiCr2O4, FeCr2O4, Cr2O3 and NiO phases exist in the scale. EDX analysis done shows varying compositions of Fe,Cr,Ni and O in outer and inner oxide scale, oxide scale/metal interface and metal. Field emission scanning electron microscope (FE-SEM) was used to investigate voids formed in the cross sections of the oxidized samples. Volume fraction of voids in the oxide scale was calculated in accordance to the cross sectional area fraction of voids in the scale. It shows that Fe-Cr-Ni alloy samples exposed in humid environment has as high as 71% more voids than that exposed in dry environment. It is concluded that the humid environment increased the number of void formed in the oxide scale, thus facilitates the exfoliation of protective scale during the high temperature oxidation

Modelling and optimization of copper electroplating adhesion strength

In this paper, Response surface methodology (RSM) was utilized to design the experiments at the settings of CuSO4 and H2SO4 concentrations and current densities. It also used for modelling and optimize the parameters on the adhesion strength of austenitic stainless steel substrate. The adhesion strength was investigated by the Teer ST-30 tester, and the structure of the samples investigated by using scanning electron microscopy (SEM). The modelling approach adopted in the present investigation can be used to predict the adhesion strength of the copper coatings on stainless steel substrate of electroplating parameters in ranges of CuSO4 100 to 200 g/ L, H2SO4 100 to 200 g / L and current density 40 to 80 mA / cm2. The results showed that, operating condition should be controlled at 200 g/L CuSO4, 100 g/L H2SO4 and 80 mA/cm2, to obtain the maximum adhesion strength 10N