60 research outputs found

    Numerical Simulation of Natural Convection Between Two Parallel Plates

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    Free convection flow is present and significant in various engineering circumstances, such as the design of heat exchangers, nuclear reactors, and many chemical processes. It is also important in the application of cooling equipment. In this project, a two-dimensional numerical model is formulated to simulate the natural convection of air between two parallel plates using a computational fluid dynamics (CFD) code. Several different situations are modeled to observe the effects on the natural convection flow

    Numerical Simulation of Natural Convection Between Two Parallel Plates

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    Free convection flow is present and significant in various engineering circumstances, such as the design of heat exchangers, nuclear reactors, and many chemical processes. It is also important in the application of cooling equipment. In this project, a two-dimensional numerical model is formulated to simulate the natural convection of air between two parallel plates using a computational fluid dynamics (CFD) code. Several different situations are modeled to observe the effects on the natural convection flow

    Silica Nanoparticles Infused Mixed Matrix Membrane For Carbon Dioxide Removal Via Membrane Gas Absorption

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    Carbon dioxide (CO2) is the most produced, heat-trapping greenhouse gas and one of the main contributors to global warming. Membrane gas absorption (MGA) is a very attractive alternative for CO2 removal as it is simple, energy efficient, less space consuming and easy to scale up. However, major issues in MGA process are improving the membrane selectivity without reducing the permeability and membrane wetting, which can increase membrane mass transfer resistance significantly. Various materials with differing properties have been researched for the synthesis of MGA membranes to capture CO2, however, mixed matrix membranes (MMM) are proving to be a promising alternative, as the addition of inorganic particles into polymers opens the possibility of augmenting the membrane performance. In this work, polyvinylidene fluoride (PVDF) was chosen as the polymer matrix and fumed silica nanoparticles were incorporated into the polymer dope to produce MMM. A defect-free asymmetric membrane with both finger-like layer and sponge-like layer was successfully synthesised using 15 wt% polymer concentration with a casting thickness of 400µm in a coagulation bath of a mixture of ethanol and water. Among the three different silica nanoparticles investigated in this study, TS-530 silica nanoparticles that had been treated with hexamethyldisilazane gave superior CO2 absorption performance in MGA process in terms of selectivity and permeability of 22.5 and 1.9 x 10-4 mol/m2s respectively at 1 wt% silica loading. This improvement of selectivity of TS-530 MMM compared to pristine PVDF membrane, which had a selectivity of 7.18 could be due to the homogenous dispersion of the nanoparticles in the PVDF polymer matrix, effectively altering the structure of the membrane to increase membrane contact area, resulting in better selectivity of CO2 over nitrogen while hardly affecting the permeability. The performance of the MMM was further improved by adding a layer of low-density polyethylene (LDPE) coating on the membrane to increase its hydrophobicity and resistance to membrane wetting. The coated MMM proved to be better than the non-coated MMM in both permselectivity and sustainability in an extended run, with CO2 absorption flux and selectivity of 2.4 x 10-4 mol/m2 s and 22.8 respectively. A dynamic model was then proposed to simulate CO2 absorption in the MGA process, taking not only the gas solubility into the liquid absorbent into account, but also the gas solubility into the membrane. The model was found to be in good fit with experimental results, with R2 values exceeding 0.92. The optimum coated MMM with superior selectivity and better resistance to membrane wetting with liquid entry pressure of 13.55 bar and contact angle of 120° was used with the best operating parameters to observe the binary gas performance over an extended period. Throughout the study of the membrane synthesis, the potential membrane CO2 separation performance was observed in regards to a multitude of parameters and its resulting physical properties, which allowed for the monitoring of membrane performance under various influences

    Pleurotus sajor-caju (PSC) Improves Nutrient Contents and Maintains Sensory Properties of Carbohydrate-based Products

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    The grey oyster mushroom, Pleurotus sajor-caju (PSC), is a common edible mushroom and is now grown commercially around the world for food. This fungus has been broadly used as food or food ingredients in various food products for a long time. To enhance the nutritional quality and sensory attributes of bakery-based products, PSC powder is used in the present study to partially replace wheat flour in baked product formulations. The nutrient content and sensory properties of rice-porridge and unleavened bread (paratha) incorporated with various levels of PSC powder were studied. These food items were formulated with either 0%, 2%, 4% or 6% of PSC powder. Results show PSC powder recorded β-glucan at 3.57g/100g. In sensory evaluation, consumers gave higher score to both rice-porridge and paratha bread containing 2-4% PSC compared to those that are not added with PSC powder. The paratha containing 4% PSC powder can be formulated with the intention in improving overall acceptability of paratha bread. Meanwhile, for rice-porridge, consumers prefer the formulated product added with 4% PSC powder. In conclusion, the addition of PSC powder to partially wheat flour can be recommended for the purpose of enhancing nutritional composition and maintaining the acceptability of carbohydrate-based products

    Obstetrics performance of women with prolonged inter-pregnancy interval (i-pi): a comparative cross-sectional study

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    BACKGROUND: The inter-pregnancy interval (I-PI) has been reported to influence the outcome of pregnancy and birth. This study was to evaluate the associated factors of I-PI and the impact of I-PI on maternal and fetal outcomes. OBJECTIVE: To determine whether prolonged inter-pregnancy interval (I-PI ≥ 60 months) is associated with higher incidence of adverse obstetrics outcomes, namely labour dystocia, pre-eclampsia, post-partum haemorrhage and fetal outcome such as prematurity compared to inter-pregnancy interval 18-59 months. METHODS: A 12 months prospective cross-sectional study in HUSM from 1st March 2013 to 28th February 2014 was conducted. The study group consisted of pregnant women, with inter-pregnancy interval more than 60 months and the control group consisted of pregnant women, with inter-pregnancy interval between 18 to 60 months. Both the study and control group were screened and selected according to the study’s criteria. There were a total of 272 patients recruited in the duration of the study, with equal number of 126 patients in each arm. Univariate and multivariate logistic regression analysis was used to estimate odds ratio and 95% confidence interval for risk of inter-pregnancy interval such as labour dystocia, pre-eclampsia, postpartum haemorrhage and prematurity. RESULTS: Women with prolonged inter-pregnancy interval (I-PI ≥ 60 months) were more likely to have labour dystocia (OR 1.92, 95% CI 1.09, 3.38; adjusted OR 1.86, 95% CI 1.03, 3.38; p=0.049) as compared to control group. Higher association of prolonged I-PI ≥ 60 months with pre-eclampsia (p=0.049) and primary postpartum haemorrhage (p=0.039). However, there were less number of prematurity (p=0.455) seen among the study group. Advance maternal age was significantly noted to have direct association with prolonged I-PI, labour dystocia, pre-eclampsia and primary postpartum haemorrhage. CONCLUSION: A prolonged inter-pregnancy interval (I-PI ≥ 60 months) is associated with adverse pregnancy and maternal outcome namely labour dystocia, pre-eclampsia and primary postpartum haemorrhage. The results of this study show an association of prolonged I-PI with adverse pregnancy and maternal outcome

    An overview of in vitro research models for Alzheimer`s disease (AD)

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    Alzheimer’s disease (AD) is the most common form of age-related dementia. It is a neurodegenerative disease characterized by two aberrant features, the amyloid plaques and the neurofibrillary tangles which result in progressive memory loss and cognitive disturbances. This has led to devastating suffering to the patient, caregivers, family and economy of the country. As a result, scientists are putting efforts in understanding the mechanisms underlying the development of the disease as well as treatment for the disease. To do so, an ideal model is required that can mimic the development of AD,demonstrating the progressive degeneration of the neurons and formation of amyloid plaques and neurofibrillary tangles. In this review paper, currently available in vitro models for AD will be disc ussed, which include the cancer, primary culture and stem cell lines, highlighting on the benefits and limitations of each. More attention will be focused on the latest established disease-specific induced pluripotent stem cells (iPSCs)isolated from familial AD patients and Dow n syndrome patients. These models have their own advantages and limitations, therefore, more research needs to be done to come up with a model that is suitable not only for fundamental understanding of the disease but also for drug discovery and development

    Effect of Different Drying Techniques on the Nutritional Values of Oyster Mushroom (Pleurotus sajor-caju)(Kesan Teknik Pengeringan Berbeza terhadap Nilai Pemakanan Cendawan Tiram (Pleurotus sajor-caju)

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    Mushrooms are basically fungi, which have fleshy and spore-bearing fruiting body. This family of fungi literally has thousands of varieties of mushroom throughout the world. Oyster mushrooms are uniquely distinctive and they do look like oysters. Drying these mushroom confer a stabilizing property to it and then can be stored for a longer period. The nutritional values of the dried oyster mushroom with different drying techniques were thus determined. There were three different drying techniques used. These include low heat air blow (LHAB, AnjaadTM), sun drying (SD) and gas laboratory oven (LO) drying. All three samples were analyzed for beta-glucan content, water activity, colour, proximate analysis and dietary fibre concentration. The result showrd that LHAB method confers the lowest water activity compared with the other two drying methods. It also has the lowest colour measurement for brightness. Mushroom samples dried by LHAB techniques contain the highest concentration of both fat and carbohydrate compared with the other two methods. Besides, SD method confers the highest beta-glucan content. On the other hand, dietary fibres observed in LO dried samples contain the highest fibre content among the three drying treatments. In conclusion, LHAB method is recommended in reducing water activity and increasing proximate contents while both SD and LO are good in preserving beta-glucan and dietary fibre contents, respectively.|| Cendawan adalah sejenis kulat yang mempunyai isi dan struktur badan yang mengandungi spora. Keluarga kulat ini dikenali mempunyai ribuan jenis varieti kulat di seluruh dunia. Cendawan tiram adalah sangat unik dan berbentuk seperti tiram. Pengeringan cendawan jenis ini akan membantu menstabilkan sifatnya supaya ia dapat disimpan dalam tempoh masa yang lama. Nilai pemakanan cendawan tiram yang dikeringkan menggunakan proses pengeringan yang berbeza telah ditentukan. Sebanyak 3 jenis teknik pengeringan telah digunakan. Teknik ini termasuklah suhu rendah berhembusan angin (LHAB) (AnjaadTM), matahari (SD) dan ketuhar makmal (LO). Semua 3 sampel telah dianalisis untuk penentuan kandungan beta-glucan, aktiviti air (aw), warna, analisis proksimat dan kandungan serabut diet. Keputusan kajian mendapati teknik LHAB menunjukkan nilai aw paling rendah berbanding 2 teknik pengeringan yang lain. Teknik LHAB juga memberi nilai warna yang terendah untuk keamatan kecerahan. Sampel cendawan yang dikeringkan menggunakan teknik LHAB mengandungi kandungan lemak dan karbohidrat paling tinggi berbanding dengan teknik pengeringan yang lain. Selain daripada itu, kaedah SD mengekalkan nilai kandungan beta-glucan yang paling tinggi. Dalam aspek yang lain, sampel yang dikeringkan dalam LO mengandungi nilai serabut diet yang paling tinggi berbanding teknik pengeringan lain. Secara ringkas, teknik LHAB disarankan untuk memperoleh nilai aw yang rendah dan kandungan proksimat yang tinggi manakala kedua-dua teknik SD dan LO masing-masing dapat mengekalkan kandungan beta-glucan dan serabut diet

    A review on the law for vehicle emission in malaysia: the position in Malaysia, The United States, and Japan / Norhazawani Bang Kipli, Nur Amira Ahmad Azhar and Nurul Aishah Amira Mohd Rosli

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    This research examines the existing laws in Malaysia on vehicle emission and to compare it with the laws in the United State and Japan. The development of the laws has started as early as 1970s in the United States with the Clean Air Act and followed closely by Japan and Malaysia in 1974 with the Environmental Quality Act 1974. Japan, however criminalizes this offence of air pollution and introduces "pollution diet" to control it. When comparing these laws, it showed that the United States has the most development and was referred by several countries, including Malaysia. International agreements and haze tracking measurements were also made but even so, there are various regulations passed in different states in the United States despite having the Clean Air Act and it varies from state to state. Japan, despite having the harshest approach, it showed that there is a significant reduction of air pollution more than 80% in a decade. Malaysia on the other hand, has its own regulations, and several efforts were made by the government to reduce emission where it must not be more than 50 HSU and new technologies were used by PUSPAKOM to control diesel exhaust emission by having particulate filters, exhaust gas recirculation and selective catalytic reduction. Some suggestions had been included in this study such as to review the provisions on vehicles in Malaysia to use a 3-way catalytic converter to reduce toxicity of emissions and to upgrade diesel fuel with less sulphur as it can reduce emission by 90%

    The effect of addition of oyster mushroom (Pleurotus sajor-caju) on nutrient composition and sensory acceptation of selected wheat- and rice-based products

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    Mushroom cultivation has been more popular recently in Malaysia. They are favoured due to their delicious flavour and low calorific value. Apart from that, they also contain high amount of protein and other essential nutrients. As recommended by food pyramid, people should take in more of their calories from whole grains-based foods than any other sources. Three selected carbohydrate based products namely rice-porridge (RP), paratha flat bread (PB) and conventional cake (CC) were formulated with dried Pleurotus sajor-caju (PSC) powder. All three products were analyzed for proximate analysis and sensory evaluation. Result shows the percentage of moisture, ash, fat and protein of RP increased in line with the levels of PSC powder used except for carbohydrate. Whereas for PB and CCs added with 2%, 4% and 6% PSC, the percentage of all nutrients were higher than control (0%) except for fat. Mushroom-based RP had significantly higher value of odour attribute as compared to control, with RP added with 6% PSC powder received the highest score. Meanwhile, mushroom-based PB received better score on textural attribute compared the control. In CC, panels prefer the cake added with 4% PSC powder as they gave higher scores for softness and flavour attributes. In conclusion, addition of PSC powder to partially replace rice and wheat flour in RP, CC and PB enhance essential nutritional components and well accepted by consumers. Thus, PSC powder can be considered to be utilized in carbohydrate–based food products with the purpose of enhancing nutrient compositions without affecting its sensory acceptance

    Application of Fuzzy Logic Controller for Safe Braking System: An Anti-Theft Tracking

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    Automotive security has become more challenging with the increasing of sophisticated modern technologies nowadays. While the transformation of automotive has brought major advancement in efficiency, it also led to the possibility of new threats in automotive field such as vehicle theft. In Malaysia, an average of sixty vehicles get stolen every day. Numbers of vehicle’s security and safety devices or system has been marketed such as safety alarms, door jammer, gearshift lock and global positioning system (GPS) tracker. However, there are also few limitations of these devices such as easily disable, notify false alarm and requires strong cellular network for continuous tracking. This paper describes the preliminary research and application of fuzzy logic based controller for braking system of stolen vehicle. In our future study, this system will be incorporated in the anti-theft tracking device with smartphone integration. In this study, two input parameters are considered which are the vehicle velocity and the sight distance. The proposed system will assist the user or vehicle owner to decide for safe braking control. Thus, reduce the risk of property loss or life loss
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