Formulation of fumed silica grease from waste transformer oil as base oil

This study aimed to formulate fumed silica (FS) grease using waste transformer oil (WTO) and to investigate the grease properties. Various unexplored application of the reused WTO due to its reusable characteristic. WTO and fresh transformer oil (ITO) were used as grease base fluid and the properties of oil and grease were evaluated using ASTM International standards and SKF’s Grease Test Kit. The oil and grease chemical compound were determined using Fourier Transform-Infrared Spectroscopy at wavenumber of 500–4000?cm^?1. It was found that WTO have high viscosity index of 96 and low moisture content of 0.05% after pre-treatment than ITO. FS greases with and without MoS₂ were classified as NLGI 2 greases when FS content was 8%. Grease formulated with MoS₂ shows better performances in term of corrosiveness, oil bleed within ?15% to +15%, oil separation less than 4%, and dropping point of >300?°C. FTIR results shows no significant different between ITO and WTO, and between all formulated greases. Based on the findings, it was concluded that WTO can be utilized as an alternative base oil in grease formulation due to the good properties exhibited by the formulated WTO-based FS grease blended with MoS₂.     

Investigation of pillar thickness variation effect on oblique rotating implantation (ORI)-based vertical double gate MOSFET

The rapid scaling of integrated circuit requires further shrinkage of lateral device dimension, which correlates with pillar thickness in vertical structure. This paper investigates the effect of pillar thickness variation on vertical double gate MOSFET (VDGM) fabricated using oblique rotating ion implantation (ORI) method. For this purpose, several scenarios of silicon pillar thickness t_si were evaluated for 20–100 nm channel length. The source region was found to merge at pillar thickness below 75 nm, which results in floating body effect and creates isolated region in the middle of pillar. The vertical devices using ORI method show better performance than those with conventional implantation method for all pillar thickness, due to the elimination of corner effect that degrades the gate control. The presence of isolated depletion region in the middle of pillar at floating body increases parasitic effect for higher drain potential. By further reduction of pillar thickness towards fully depleted feature, the increase in gate-to gate charge coupling improves the performance of ORI-based vertical double gate MOSFET, as evident in near-ideal swing value and lower DIBL, compared to the partially depleted and body-tied device.     

Performance and Microstructural Study on Soap Using Different Fatty Acids and Cations

The desired benefits of the finished soap product are governed by a professional selection of appropriate raw materials, the manufacturing process or both. A better understanding of the crystallization of the soap microstructure is needed which has direct effects on the properties of final products. Soap microstructures and soap composition are not only determined by the length of hydrophobic fatty chain, saturation extent of fatty acid chain, fatty acid distribution but also by the cation effect. Thus, four different fatty acid compositions and the effect of sodium and potassium cations were studied. The performance of the potassium and sodium bar soaps prepared was monitored and was correlated with solid phase thermal analysis. The microstructural effect was examined using ATR-FTIR, FESEM and XRD. The specific ion effect and ion interaction involving both cations and carboxylate anions on different chemical compositions was correlated.     

Analytical performance of 3?m and 3?m +1 armchair graphene nanoribbons under uniaxial strain

The electronic band structure and carrier density of strained armchair graphene nanoribbons (AGNRs) with widths of n =3 m and n =3 m +1 were examined using tight-binding approximation. The current-voltage (I-V) model of uniaxial strained n =3 m AGNRs incorporating quantum confinement effects is also presented in this paper. The derivation originates from energy dispersion throughout the entire Brillouin zone of uniaxial strained AGNRs based on a tight-binding approximation. Our results reveal the modification of the energy bandgap, carrier density, and drain current upon strain. Unlike the two-dimensional graphene, whose bandgap remains near to zero even when a large strain is applied, the bandgap and carrier density of AGNRs are shown to be sensitive to the magnitude of uniaxial strain. Discrepancies between the classical calculation and quantum calculation were also measured. It has been found that as much as 19% of the drive current loss is due to the quantum confinement. These analytical models which agree well with the experimental and numerical results provide physical insights into the characterizations of uniaxial strained AGNRs.     

Synthesis of multiwalled carbon nanotubes supported on M/MCM-41 (M = Ni,Co and Fe) mesoporous catalyst by chemical vapour deposition method

Aim of this research is to develop an effective way in producing multi-walled carbon nanotubes (MWNTs) via chemical vapour deposition method using acetylene as carbon source and synthesized mesoporous M/MCM-41 (M?=?Ni, Co and Fe) as catalyst. The mesoporous MCM41 is synthesized by using sodium metasilicate as silica source of frameworks and cetyltrimethylammonium bromide as template. The effect of temperatures and growth times are investigated to produce MWNTs with high yield and high quality. The low-angle X-ray diffraction (XRD), Fourier transform infrared spectroscopy and scanning electron microscopy results verified the formation of MCM41. Meanwhile, high-angle XRD, Raman spectra and transmission electron microscopy results confirmed the synthesized carbon nanotubes at 600?°C and growth time for 30 min are multi-walled. The yield obtained is 1353 mg in 30 min. It shows that the MCM-41 has a promising potential to produce MWNTs at low cost and shorter duration.     

The effect of magnetic and optic field in water electrolysis

Hydrogen production via water electrolysis was studied under the effect of magnetic and optical field. A diode solid state laser at blue, green and red were utilized as optical field source. Magnetic bar was employed as external magnetic field. The green laser has shown a greatest effect in hydrogen production due to its non-absorbance properties in the water. Thus its intensity of electrical field is high enough to dissociation of hydronium and hydroxide ions during orientation toward polarization of water. The potential to break the autoprotolysis and generate the auto-ionization is the mechanism of optical field to reveal the hydrogen production in water electrolysis. The magnetic field effect is more dominant to enhance the hydrogen production. The diamagnetic property of water has repelled the present of magnetic in water. Consequently the water splitting occurs due to the repulsive force induced by the external magnetic field. The magnetic distributed more homogenous in the water to involve more density of water molecule. As a result hydrogen production due to magnetic field is higher in comparison to optical field. However the combination both fields have generated superior effect whereby the hydrogen yields nine times higher in comparison to conventional water electrolysis.     

Studies on influence of hydrogen and carbon monoxide concentration on reduction progression behavior of molybdenum oxide catalyst

Temperature programmed reduction (TPR) analysis was applied to investigate the chemical reduction progression behavior of molybdenum oxide (MoO₃) catalyst. The composition and morphology of the reduced phases were characterized by X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS), and field emission scanning electron microscopy (FE-SEM). The reduction progression of MoO₃ catalyst was attained with different reductant types and concentration (10% H₂/N₂, 10% and 20% CO/N₂ (%, v/v)). Two different modes of reduction process were applied. The first approach of reduction involved non-isothermal mode reduction up to 700 °C, while the second approach of reduction involved the isothermal mode reduction for 60 min at 700 °C. Hydrogen temperature programmed reduction (H₂-TPR) results showed the reduction progression of three-stage reduction of MoO₃ (Mo⁶⁺ → Mo⁵⁺ → Mo⁴⁺ → Mo⁰) with Mo⁵⁺ and Mo⁴⁺. XRD analysis confirmed the formation of Mo₄O₁₁ phase as an intermediate phase followed by MoO₂ phase. After 60 min of isothermal reduction, peaks of metallic molybdenum (Mo) appeared. Whereas, FESEM analysis showed porous crater-like structure on the surface cracks of MoO₂ layer which led to the growth of Mo phase. Meanwhile, the reduction of MoO₃ catalyst in 10% carbon monoxide (CO) showed the formation of unstable intermediate phase of Mo₉O₂₆ at the early stage of reduction. Furthermore, by increasing 20% CO led to the carburization of MoO₂ phase, resulted in the formation of Mo₂C rather than the formation of metallic Mo, as confirmed by XPS analysis. Therefore, the presented study shows that hydrogen gave better reducibility due to smaller molecular size, which contributed to high diffusion rate and achieved deeper penetration into the MoO₃ catalyst compared to carbon monoxide reductant. Hence, the reduction of MoO₃ in carbon monoxide atmosphere promoted the formation of Mo₂C which was in agreement with the thermodynamic assessment.     

部件运送系统的设计及其在微成形领域中的应用(英文)

当前对微成形的研究主要集中在基础理论以及实验过程上,而忽略了某些和实际生产相关的关键问题。例如,一个微成形机,如果没有与之相匹配的合适的部件传送系统,就难于满足工业化生产的要求,而且很不切实际。连续的生产过程需要的不仅仅是高效率的生产设备本身,还需要与其效率和生产过程同步的材料/部件运送系统。这一系统的功能应该包括自动将成品/零件运送出成形环境并打包以便运输。文章提出了一种微型冲压成品/零件的运送策略,工作主要集中在运送设备及整个系统的研究以及设计考虑,并已应用于英国思特莱斯克莱德大学研制的一套全新的板材微成形设备上。该系统进给方法的特征以及定位精度采用有限元方法进行分析,现已构建成功,并经过了试验校准。     

The role of state and market in the Malaysian housing sector

This paper discusses the development of housingpolicy in Malaysia, focusing on the role ofstate and market in low-income housingprovision. Since independence, the state hasstrongly intervened in the housing sector, andits housing policies have expressed its racialand political preferences in housingdevelopment and distribution. The privatesector performs better than the public sector.But the excessive state control over housinghinders the development of the market, while the potential of the private sector's capacityis under-utilised. The paper illustrates theproblems of the housing system and ends withsome recommendations for ways to overcome theseproblems.