Showing papers by "Universiti Teknologi Malaysia published in 2009"

A Review on Augmented Reality for Virtual Heritage System

Abstract: Augmented reality is one of the emerging technologies to reconstruct the historical building and monument in the previous era, where the user experiences with the real environment or virtual scene. In education, Virtual Heritage becomes as a platform of learning, motivating and understanding of certain events and historical elements for the students and researchers. The significance of reconstruction of digital culture heritage are to preserve, protect and interpret of our cultural and history. In recent year, there are a number of significant researches and techniques that have been developed, which is focusing on virtual restitution of historical sites. This paper will present an overview on augmented reality in Virtual Heritage system and also consists with the explanation of techniques to reconstruct the historical sites.

Application of self-tuning fuzzy pid controller on industrial hydraulic actuator using system identification approach

Abstract: In this paper, Self Tuning Fuzzy PID controller is developed to improve the performance of the electro-hydraulic actuator. The controller is designed based on the mathematical model of the system which is estimated by using System Identification technique. The model is performed in a linear discrete model to obtain a discrete transfer function for the system. Model estimation procedures are done by using System Identification Toolbox in Matlab. Data for model estimation is taken from experimental works. Fuzzy logic is used to tune each parameter of PID controller. Through simulation in Matlab by selecting appropriate fuzzy rules are designed to tune the parameters Kp, Ki, and Kd of the PID controller, the performance of the hydraulic system has improved significantly compare to conventional PID controller.

Application of microbioreactors in fermentation process development: a review

Abstract: Biotechnology process development involves strain testing and improvement steps aimed at increasing yields and productivity This necessitates the high-throughput screening of many potential strain candidates, a task currently mainly performed in shake flasks or microtiter plates However, these methods have some drawbacks, such as the low data density (usually only end-point measurements) and the lack of control over cultivation conditions in standard shake flasks Microbioreactors can offer the flexibility and controllability of bench-scale reactors and thus deliver results that are more comparable to large-scale fermentations, but with the additional advantages of small size, availability of online cultivation data and the potential for automation Current microbioreactor technology is analyzed in this review paper, focusing on its industrial applicability, and directions for future research are presented

Microstrip Antenna's Gain Enhancement Using Left-Handed Metamaterial Structure

Abstract: The design, simulation and fabrication of a left-handed metamaterial (LHM) structure is presented. The combination of the modifled square rectangular Split Ring Resonator (SRR) and the Capacitance Loaded Strip (CLS) were used to obtain the negative value of permeability, " and the negative permittivity, ". Nicolson- Ross-Wier approach was used to identify the double negative region. A good agreement between simulated and measured results has been achieved. Upon incorporation with a single patch microstrip antenna, the performance of the antenna was improved where the gain of the microstrip antenna was increased up to 4dB, and its bandwidth widens from 2.9% to 4.98%. These improvements are due to the negative refraction characteristics of the LHM structure that acts as a lens when placed in front of the antenna.

Measurement of streaming potential coupling coefficient in sandstones saturated with high salinity NaCl brine

Abstract: [1] We present measurements of the streaming potential coupling coefficient in intact sandstone samples saturated with NaCl brines at concentrations up to 5.5 molL−1. The values we record at low salinity are consistent with those reported previously. As brine salinity increases, the coupling coefficient decreases in magnitude, but is still measureable up to the saturated concentration limit. The magnitude of the zeta potential also decreases with increasing salinity, but approaches a constant value at high salinity. This behaviour is not captured by current models of the electrical double layer. Our results suggest that streaming potential measurements may be used to monitor flow in saline subsurface environments such as deep saline aquifers and hydrocarbon reservoirs. However, they were obtained at laboratory temperature. Future work will focus on the effect of elevated temperatures at high salinity.

Coagulation and flocculation treatment of wastewater in textile industry using chitosan

Abstract: Aluminum sulfate (alum), ferrous sulfate, ferric chloride and ferric chloro-sulfate were commonly used as coagulants. However, a possible link of Alzheimer’s disease with conventional aluminium based coagulants has become an issue in wastewater treatment. Hence, special attention has shift towards using biodegradable polymer, chitosan in treatment, which are more environmental friendly. Moreover, chitosan is natural organic polyelectrolyte of high molecular weight and high charge density which obtained from deacetylation of chitin. Experiments were carried out on textile industry wastewater by varying the operating parameters, which are chitosan dosage, pH and mixing time in order to study their effect in flocculation process by using chitosan. The results obtained proved that chitosan had successfully flocculated the anionic suspended particles and reduce the levels of Chemical Oxygen Demand (COD) and turbidity in textile industry wastewater. The optimum conditions for this study were at 30 mg/l of chitosan, pH 4 and 20 minutes of mixing time with 250 rpm of mixing rate for 1 minute, 30rpm of mixing rate for 20 minutes and 30 minutes of settling time. Moreover, chitosan showed the highest performance under these conditions with 72.5% of COD reduction and 94.9% of turbidity reduction. In conclusion, chitosan is an effective coagulant, which can reduce the level of COD and turbidity in textile industry wastewater

Modeling and Simulation of Photovoltaic Water Pumping System

Abstract: This paper presents modeling of a simple but efficient photovoltaic water pumping system. The system employs maximum power point tracker (MPPT). Two MPPT algorithms, subsystems and control methods will be modeled and simulated using Matlab and Simulink with actual irradiance data. Simulation results will be presented in terms of performance parameters such as total energy produced and total volume of water pumped per day. The results further validate that MPPT can significantly improve efficiency and performance of PV water pumping system compared to the system without MPPT.

Forecasting Gold Prices Using Multiple Linear Regression Method

Abstract: Problem statement: Forecasting is a function in management to assist decision making. It is also described as the process of estimation in u nknown future situations. In a more general term it is commonly known as prediction which refers to estimation of time series or longitudinal type data. Gold is a precious yellow commodity once used as money. It was made illegal in USA 41 years ago, but is now once again accepted as a potential curre ncy. The demand for this commodity is on the rise. Approach: Objective of this study was to develop a forecasti ng model for predicting gold prices based on economic factors such as inflation, currency pri ce movements and others. Following the melt-down of US dollars, investors are putting their money in to gold because gold plays an important role as a stabilizing influence for investment portfolios. Du e to the increase in demand for gold in Malaysian and other parts of the world, it is necessary to de velop a model that reflects the structure and patte rn of gold market and forecast movement of gold price. The most appropriate approach to the understanding of gold prices is the Multiple Linear Regression (M LR) model. MLR is a study on the relationship between a single dependent variable and one or more independent variables, as this case with gold price as the single dependent variable. The fitted model of MLR will be used to predict the future gol d prices. A naive model known as "forecast-1" was considered to be a benchmark model in order to evaluate the performance of the model. Results: Many factors determine the price of gold and based on "a hunch of experts", several economic factors h ad been identified to have influence on the gold prices. Variables such as Commodity Research Bureau future index (CRB); USD/Euro Foreign Exchange Rate (EUROUSD); Inflation rate (INF); Money Supply (M1); New York Stock Exchange (NYSE); Standard and Poor 500 (SPX); Treasury Bill (T-BILL) and US Dollar index (USDX) were considered to have influence on the prices. Paramet er estimations for the MLR were carried out using Statistical Packages for Social Science package (SP SS) with Mean Square Error (MSE) as the fitness function to determine the forecast accuracy. Conclusion: Two models were considered. The first model considered all possible independent variables . The model appeared to be useful for predicting the price of gold with 85.2% of sample variations i n monthly gold prices explained by the model. The second model considered the following four independent variables the (CRB lagged one), (EUROUSD lagged one), (INF lagged two) and (M1 lagged two) to be significant. In terms of prediction, the second model achieved high level of predictive accu racy. The amount of variance explained was about 70% and the regression coefficients also provide a means of assessing the relative importance of individual variables in the overall prediction of g old price.

Comparison of signal-to-noise, blank determination, and linear regression methods for the estimation of detection and quantification limits for volatile organic compounds by gas chromatography.

Abstract: LOD and LOQ are two important performance characteristics in method validation. This work compares three methods based on the International Conference on Harmonization and EURACHEM guidelines, namely, signal-to-noise, blank determination, and linear regression, to estimate the LOD and LOQ for volatile organic compounds (VOCs) by experimental methodology using GC. Five VOCs, toluene, ethylbenzene, isopropylbenzene, n-propylbenzene, and styrene, were chosen for the experimental study. The results indicated that the estimated LODs and LOQs were not equivalent and could vary by a factor of 5 to 6 for the different methods. It is, therefore, essential to have a clearly described procedure for estimating the LOD and LOQ during method validation to allow interlaboratory comparisons.

Spatio-Temporal Variability of Rainfall Over Bangladesh During the Time Period 1969-2003

Abstract: Spatial and temporal variability of rainfall in Bangladesh has been studied in this paper from thirty-five years (1969-2003) of rainfall data recorded at 24 rain gauges distributed over the country. Long-term annual average rainfall, coefficient of variation of annual rainfall, precipitation concentration and aridity indices at each station have been computed and then interpolated using kriging method within a geographic information system to show the temporal and spatial variability of rainfall. Mann-Kendall test has been used to analyze the trend in rainfall data in different recording stations and the Sen’s slope method has been used to determine the magnitude of change. A moderate variation in inter-annual rainfall and high variation in intra-annual rainfall in Bangladesh have been observed. Non-significant positive trend of annual, monsoon and pre-monsoon rainfall, and a negative trend in winter rainfall are found in Bangladesh. Spatial distribution of rainfall trends shows that rainfall is increasing in the coastal zone and northern Bangladesh, and decreasing in the central part of the country. A declining trend of precipitation concentration is also observed in most of the stations. These results may be a first indication of the precipitation response to global warming – a hypothesis which needs to be further investigated by means of climate model projections.

Combined xanthorrhizol-curcumin exhibits synergistic growth inhibitory activity via apoptosis induction in human breast cancer cells MDA-MB-231

Abstract: It has been suggested that combined effect of natural products may improve the treatment effectiveness in combating proliferation of cancer cells. The present study was undertaken to evaluate the possibility that the combination of xanthorrhizol and curcumin might show synergistic growth inhibitory effect towards MDA-MB-231 human breast cancer cells via apoptosis induction. The effective dose that produced 50% growth inhibition (GI50) was calculated from the log dose-response curve of fixed-combinations of xanthorrhizol and curcumin generated from the sulforhodamine B (SRB) assay. The experimental GI50 value was used to determine the synergistic activity of the combination treatment by isobolographic analysis and combination-index method. Further investigation of mode of cell death induced by the combination treatment was conducted in the present study. Isobole analysis revealed that substances interaction was synergistic when xanthorrhizol and curcumin were added concurrently to the cultures but merely additive when they were added sequentially. The synergistic combination treatment was then applied to the cultures to investigate the mode of cell death induced by the treatment. Immunofluorescence staining using antibody MitoCapture™ revealed the possibility of altered mitochondrial transmembrane potential, which is one of the hallmark of apoptosis. Hoechst 33258 nuclear staining assay showed the rate of apoptosis of MDA-MB-231 cells to increase in response to the treatment. Apoptotic cell death was further confirmed by DNA fragmentation assay, where internucleosomal excision of DNA was induced upon treatment with xanthorrhizol-curcumin. This is the first time the combined cytotoxic effect of xanthorrhizol and curcumin on MDA-MB-231 cells has been documented and our findings provide experimental support to the hypothesis that combined xanthorrhizol-curcumin showed synergistic growth inhibitory activity on MDA-MB-231 cells via apoptosis induction.

Chromium(VI) resistance and removal by Acinetobacter haemolyticus

Abstract: The present work highlighted the studies on Cr(VI) reduction by cells of Acinetobacter haemolyticus (A. haemolyticus). The strain tolerated 90 mg Cr(VI) l−1 in LB broth compared to only 30 mg Cr(VI) l−1 in LB agar. From the FTIR analysis, the Cr(III) species formed was also most likely to form complexes with carboxyl, hydroxyl, and amide groups from the bacteria. A TEM study showed the absence of precipitates on the cell wall region of the bacteria. Instead, microprecipitates were observed in the cytoplasmic region of the cells, suggesting the transportation of Cr(VI) into the cells. Intracellular reduction of Cr(VI) was supported by a reductase test using soluble crude cell-free extracts. The specific reductase activity obtained was 0.52 µg Cr(VI) reduced per mg of protein an hour at pH 7.2 and 37°C. Our results indicated that A. haemolyticus can be used as a promising microorganism for Cr(VI) reduction from industrial wastewaters.