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Search Results: 1 - 10 of 8458 matches for " Sim Yee Chin "
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Hydrogen as Carbon Gasifying Agent During Glycerol Steam Reforming over Bimetallic Co-Ni Catalyst  [PDF]
Chin Kui Cheng, Rwi Hau Lim, Anabil Ubil, Sim Yee Chin, Jolius Gimbun
Advances in Materials Physics and Chemistry (AMPC) , 2012, DOI: 10.4236/ampc.2012.24B043
Abstract: Alumina-supported bimetallic cobalt-nickel catalyst has been prepared and employed in a fixed-bed reactor for the direct production of synthesis gas from glycerol steam reforming. Physicochemical properties of the 5Co-10Ni/85Al2O3 catalyst were determined from N2-physisorption, H2-chemisorption, CO2 and NH3-temperature-programmed desorption measurements as well as X-ray diffraction analysis. Both weak and strong acid sites are present on the catalyst surface. The acidic:basic ratio is about 7. Carbon deposition was evident at 923 K; addition of H2 however has managed to reduce the carbon deposition. Significantly, this has resulted in the increment of CH4 formation rate, consistent with the increased carbon gasification and methanation. Carbon deposition was almost non-existent, particularly at 1023 K. In addition, the inclusion of hydrogen also has contributed to the decrease of CO2 and increase of CO formation rates. This was attributed to the reverse water-gas-shift reaction. Overall, both the CO2:CO and CO2:CH4 ratios decrease with the hydrogen partial pressure.
铜掺杂SBA-15的pH调节法直接合成及其在N_2O分解反应中的催化性能
李金林,刘光荣,Chin,Sim,Yee
中南民族大学学报(自然科学版) , 2012,
Abstract: 酸性条件下,用环六亚甲基四胺作为pH调节剂,采用pH调节法直接合成了铜同构替代掺杂的SBA-15中孔分子筛(Cu/SBA-15).采用X-射线衍射(XRD)、扫描电子显微镜-能量色散X射线光谱(SEM-EDX)、透射电子显微镜(TEM)以及傅立叶变换红外光谱(FT-IR)等技术对目标材料进行了表征.结果表明:该材料具有六方中孔有序结构,且环六亚甲基四胺显著影响了铜和SBA-15硅骨架的结合,在水热合成过程中,环六亚甲基四胺分解释放出氨气,增加了体系的pH值,有助于更多的铜进入到分子筛的骨架中.该材料可用于N2O分解反应的催化剂,其中Cu/SBA-15(110)在600℃下具有优异的催化活性,可分解50%N2O.
Study on Test Compaction in High-Level Automatic Test Pattern Generation (ATPG) Platform  [PDF]
Ayub Chin Abdullah, Chia Yee Ooi
Circuits and Systems (CS) , 2013, DOI: 10.4236/cs.2013.44046
Abstract:

Advancements in semiconductor technology are making gate-level test generation more challenging. This is because a large amount of detailed structural information must be processed in the search process of automatic test pattern generation (ATPG). In addition, ATPG needs to deal with new defects caused by process variation when IC is shrinking. To reduce the computation effort of ATPG, test generation could be started earlier at higher abstraction level, which is in line with top-down design methodology that has become more popular nowadays. In this research, we employ Chen’s high-level fault model in the high-level ATPG. Besides shorter ATPG time as shown in many previous works, our study showed that high-level ATPG also contributes to test compaction. This is because most of the high-level faults correlate with the gate-level collapsed faults especially at input/output of the modules in a circuit. The high-level ATPG prototype used in our work is mainly composed by constraint-driven test generation engine and fault simulation engine. Experimental result showed that more reduced/compact test set can be generated from the high-level ATPG.

Ethnic Socialization: A Case of Malaysian Malay and Chinese Public Universities Students Experiences
Chin Yee Mun
International Journal of Social Science and Humanity , 2013, DOI: 10.7763/ijssh.2013.v3.307
Abstract: By and large, Malaysians associate themselves with certain ethnic identities. Such identification is clearly visible in most Malaysian public universities. This paper relates Malaysian Malay and Chinese public universities students’ ethnic identification to their ethnic socialization experiences. Focus group discussions with Malay and Chinese students were conducted in four Malaysian public universities. Outcomes from the focus group discussions reveal the roles of cultural and competition socialization experiences in constructing the students ethnic identity. These ethnic socialization experiences played an important role in constructing ethnic consciousness among the students.
A Study of Biomass Fuel Briquettes from Oil Palm Mill Residues
Chin Yee Sing,M. Shiraz Aris
Asian Journal of Scientific Research , 2013,
Abstract: This study presents a systematic approach in utilizing the large amount of oil palm mill residues that are loosely-bounded and have low energy density. The rate of waste materials (palm kernel shell, palm fiber and empty fruit bunches) generated by oil palm mills amounted to about 34 million tonnes in 2010. Efforts have been made to increase the energy density of the loosely-bounded waste materials, in which solid fuel briquettes made of densified oil palm residues would contribute towards a more efficient utilization of the waste material. This work focused on determining a fuel briquette with an optimum ratio of waste materials mixtures that has considerably high heating value and good mechanical properties. As part of the densification process, the waste material was pulverized and then compacted using a 200 kN force into 40 mm diameter briquettes. The heating values, proximate analysis, ultimate analysis and burning profile of the briquettes were studied. The end result was an optimised solid fuel with relatively high energy content made from a suitable mixing ratio of the different palm oil mill residues and an appropriate binder to ensure acceptable mechanical strength.
An Experimental Investigation on the Handling and Storage Properties of Biomass Fuel Briquettes Made from Oil Palm Mill Residues
Chin Yee Sing,Mohd. Shiraz Aris
Journal of Applied Sciences , 2012,
Abstract: This study is about experimental investigation on solid fuel briquettes made of oil palm mill residues that exhibit optimum handling and storage properties. One of the major technical challenges in utilizing biomass waste material as a solid fuel is the handling and storage issues of loose and wet waste material. The solid biomass fuel briquettes made from different types and combinations of palm oil mill residues were explored for optimum storage and handling features. A solution to improving the handling and storage properties of loosely-bound oil palm mill residues is proposed in this work via a densification process known as fuel briquetting. Raw oil palm waste material was pulverized and compacted with a 159 MPa pressing pressure to form 40 mm diameter solid fuel briquettes. It was found that a fuel briquette with a 60:40 palm kernel shell to mesocarp fiber ratio using waste paper as its binding agent gave the best mechanical properties without sacrificing the combustion properties of the solid fuel.
Optimal Design and Control of a Torque Motor for Machine Tools  [PDF]
Yee-Pien YANG, Shih-Chin YANG, Jieng-Jang LIU
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2009, DOI: 10.4236/jemaa.2009.14033
Abstract: This paper presents a systematic approach of optimal design and control of a surface-mount, permanent-magnet synchronous torque motor for the next-generation machine tools. A step-by-step procedure of optimization integrates multiple performance objectives and constraints to help the designer make the best decision on the final motor geometry from both design and control perspectives. In the perspective of design, a torque motor with concentrated windings and similar numbers of slots and poles may achieve the desired performance after optimization for multiple objectives, leading to a sinusoidal flux density for a nearly ripple-free torque distribution. From the control perspective, an optimal current waveform with an ideal shift angle is determined for each phase by aligning the current excitation with the back electromotive force. Both design and control of the surface-mount, permanent magnet machine are verified by the finite element method, and a prototype is fabricated for performance validation.
High cell density and latent membrane protein 1 expression induce cleavage of the mixed lineage leukemia gene at 11q23 in nasopharyngeal carcinoma cell line
Peter Yee, Sai-Peng Sim
Journal of Biomedical Science , 2010, DOI: 10.1186/1423-0127-17-77
Abstract: In this study, cells were seeded at various densities to induce apoptosis. Genomic DNA extracted was processed for Southern hybridization. In order to investigate the role of EBV, especially the latent membrane protein 1 (LMP1), LMP1 gene was overexpressed in NPC cells and chromosome breaks were analyzed by inverse polymerase chain (IPCR) reaction.Southern analysis revealed that high cell density resulted in cleavage of the mixed lineage leukemia (MLL) gene within the breakpoint cluster region (bcr). This high cell density-induced cleavage was significantly reduced by caspase inhibitor, Z-DEVD-FMK. Similarly, IPCR analysis showed that LMP1 expression enhanced cleavage of the MLL bcr. Breakpoint analysis revealed that these breaks occurred within the matrix attachment region/scaffold attachment region (MAR/SAR).Since MLL locates at 11q23, a common deletion site in NPC, our results suggest a possibility of stress- or virus-induced apoptosis in the initiation of chromosome rearrangements at 11q23. The breakpoint analysis results also support the role of chromatin structure in defining the site of chromosome rearrangement.Nasopharyngeal carcinoma (NPC) is a common cancer in Asia, especially in Southern China and South East Asia [1]. NPC is well associated with chromosome rearrangements. Among them, chromosome gains are commonly found in 12p11.2-p12, 12q14-q21, 2q24-q31, 1q31-qter, 3q13, 1q13.3, 5q21, 6q14-q22, 7q21, 8q11.2-q23 and 18q12-qter. On the other hand, chromosome deletions are commonly found in 3p14-p21, 11q23-qter, 16q21-qter and 14q24-qter [2]. Much effort has been made to identify the candidate tumor suppressor genes and oncogenes, but studies investigating the mechanism(s) leading to the chromosome anomalies are rather lacking.Epstein-Barr virus (EBV) is strongly associated with NPC [3] although the EBV genome is not required for epithelial to mesenchymal transition of NPC cells [4]. Nevertheless, various EBV antigens had been used in the diagnosis of NPC [
Antioxidative and Antibacterial Activities of Pangium edule Seed Extracts
Fook Yee Chye,Kheng Yuen Sim
International Journal of Pharmacology , 2009,
Abstract: Phenolic and alkaloid extracts of Pangium edule Reinw (Flacourtiaceae) seed were investigated for their antioxidative activities using DPPH radical scavenging and β-carotene bleaching assays. The extracts were evaluated for antibacterial activity against Salmonella typhimurium and Listeria monocytogenes. The acetone extract with higher phenolic content (22.22±0.05 mg GAE g-1) showed the most potent antioxidative activity in both DPPH radical scavenging and β-carotene bleaching assays as compared to other extracts. The phenolic extract seems to have stronger inhibitory against L. monocytogenes than S. typhimurium. The free phenolic acid extract was found to have the highest Minimum Inhibition Concentration (MIC) among the seed extracts, indicates its weak antibacterial activity against both bacteria. Nevertheless, both tested pathogens were killed at the Minimum Bactericidal Concentration (MBC) of 30.3 and 55.5 mg mL-1, respectively, for the phenolic extracts. Significant correlation (p<0.05) was observed between the total phenolic content and its antioxidative activity (r = 0.878) as well as antibacterial (r = 0.840) activity suggesting that phenolics of the seed extract could be potential sources of natural antioxidant and antibacterial.
Atherosclerosis in the elderly: a heavy burden to bear

Sze Piaw Chin,Kui Hian Sim,

老年心脏病学杂志(英文版) , 2005,
Abstract: The World Health Organization estimates there are over thirty-two million major atherothrombotic events oc-cur worldwide each year with nearly seventeen million di-rectly attributable deaths.' Atherothrombosis as the name refers to blood clot formation within an arterial vessel. It may occur de novo, usually over an atherosclerotic seg-ment of the vessel, or embolised from a proximal source." These clots cause the blood vessel lumen to be-come totally or sub-totally occluded and, depending on the site and supply, lead clinically to unstable angina and myocardial infarction, ischemic strokes or leg claudica-tion. Acute myocardial infarction ( AMI) alone account for 25% of all deaths in the United States and is the leading cause of death in the world including many of the developing countries.3 It is of little suiprise therefore that from the cardiologists' standpoint, the bulk of our work whether as researchers or clinicians have been channeled towards the prevention, regression or at least delaying the process of atherothrombosis and minimizing its risk of re-currence. Yet we must be mindful that atherothrombosis is a generalized and progressive disease. Indeed over a quarter of patients with vascular disease would involve 2 or more vascular beds in their lifetime.4 For example, patients with a first stroke or peripheral arterial disease (PAD) has a 2 to 4-fold increased risk of AMI. Patients who have had an AMI are themselves at 5-fold increased risk of a further heart attack. The life-expectancy of pa-tients with a history of stroke, PAD or myocardial infarc-tion is also reduced.4'5 But to screen all patients with suspected cardiovascular disease for concomitant peripher-al disease would lead to unnecessary risks from longer ra-diation exposure, higher amount of contrast used and costs. Hence the original article by Rigatelli et al in this issue addresses an important issue on which patient scheduled for coronary angiogram should also undergo aorto-iliac studies.6 Indeed the clinical issue of whether it is justified to perform additional scans is also highlighted here.
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