Volume 17 (2005)

Table of Contents

No. Article



Penggantian Sebahagian Pasir dengan Debu Kuari ke atas Ciri Konkrit Prestasi Tinggi Baru (Partial Replacement of Sand with Quarry Dust on the Properties of Fresh High Performance Concrete)
Muhammad Fauzi Mohd. Zain, Sudharshan Naidu Raman, Azimin Samsul Tazilan, Abdul Halim Ismail, Mazlan Tahir & Zulhairuse Md DarusAbstract

This study discusses the influence of partial replacement of sand with quarry dust on the properties of fresh high performance concrete. Considering the decrease in the sources of natural sand, it is necessary to identify alternative source, such as quarry dust to reduce the utilisation of sand in the industries requiring it. In this study, replacement proportion of sand with quarry dust used was 20% in all the high performance concrete mixes except in the normal Portland cement control high performance concrete mix. The properties of fresh high performance concrete were determined in the aspects of slump, slump flow, V-Funnel flow, air content, density and temperature. Results obtained showed that partial replacement of sand with quarry dust were able to increase the workability and flowability, as well as the air content of fresh high performance concrete. Besides that, it was observed that V-Funnel flow was more suitable to determine the flowability of fresh high performance concrete compared to the conventional slump flow.
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2. Determination of Enhancement in D-region Electron Density using Solar Flare Model and GOES- 7 Measurements
Mardina Abdullah & Ahmad Faizal Mohd ZainAbstract
This investigation elucidates the enhancement of production of electrons in the ionospheric D region by soft solar X-ray flares. A simple solar X-ray flare model is established for the purpose of this study. The in-step variation of calculated enhanced electron densities with measured values of enhanced flux intensities obtained by the GOES7 X-ray detector is understood quantitatively by the difference of arrival time of the maximum enhanced electron density with the arrival time maximum enhanced flux intensity i.e., the arrival time lag. This is compared with time lag taken from the X-ray flare model under the condition that the enhanced the electron densities are much smaller than electron density in a quiet state. The comparison of theoretical time lag or the response rate shows a good agreement with that obtained by measurements. By using this model, physical quantities such as the decreasing slope coefficient of flare model b( , z) are described in detail to identify their effects to enhanced electron densities. Good or poor in-step variation of enhanced electron densities to enhanced flux intensities through their increasing, maximum and decreasing stage is mostly dependent on fundamental physical quantities b( , z), by evaluation of the response rate. Time lag, which is inversely proportional to b( , z), shows good response. The temporal variation of b( , z) is also studied. This result can also be applied to disturbance phenomena that have a similar form.
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3. Comparing Linear and Bilinear Models on Water Level for the Kelantan River in Malaysia
Azami Zaharim, Mohd Sahar Yahya, Ibrahim Mohamed, Abdul Halim Ismail, Zuhairuse Md Darus & Zulkifli Mohd NopiahAbstract
Slirveyed from 160 time series data used in scientific articles concluded that 10-13% of them were generated by the nonlinear process. Several nonlinear models are available but only the bilinear model will be considered here. The bilinear model is basically an extension of the linear model ARIMA. It was first introduced by control theorists in 1972 before it was documented by Granger and Anderson in 1978. The bilinear model is believed to be able to fit hydrological and meteorological data well. In this paper; the coefficients of a special case of bilinear model, BL(1,1,1,1), are estimated using nonlinear least squares method. Results of modeling the linear and bilinear models on water level data from the Kelantan river in Malaysia when compared and evaluated gave better fitting to the bilinear model.
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4. Shear Strength Parameters of Unsaturated Residual Soils
Bujang B.K. Huat, Faisal Hj. Ali, Affendi Abdullah, Saravanan Mariappan & Soenita HashimAbstract
The shear strength envelope for unsaturated soil requires that three shear strength parameters be defined namely, c’, ø’ and øb. These parameters can be measured in the laboratory. The c’ and ø’ parameters can be measured using standard laboratory equipment on saturated soil specimen. However conventional triaxial and direct shear equipment require modifications prior to their use, i.e. for suction induced tests on unsaturated soils to measure the øb (i.e. the change in shear strength with respect to suction). This paper describes the modification made to the standard laboratory triaxial and shear box and outline the test performed for measuring the shear strength parameters of unsaturated residual soils. The value cohesion, c’ is found to increase with increase in the matric suction. For a given level of matric suction, the cohesion appear to increase with increase in the soil weathering grade, i.e as the soils/rocks becomes more weathered. The angle of friction, ø’ decreases with increase in the soils weathering grade, but the angle of friction or change in shear strength with change in suction, øb , increases when the soil becomes more weathered. The values of øb are generally lower than ø’.
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5. Penggunaan Penggugusan Subtraktif bagi Menjana Peraturan Kabur (The Use of Substractive Clustering Method to Generate Fuzzy Rules)
Agus Priyono, Muhammad Ridwan, Ahmad Jais Alias, Riza Atiq O. K. Rahmat, Azmi Hassan & Mohd. Alauddin Mohd. AliAbstract
Many methodologies to develop fuzzy logic rules have been previously studied. A fuzzy logic is well known because of its ability to offer a moderate method to translate the fuzzy, noise, unaccurate or lost input. The fuzzy logic is based on the emphirical method depending on the operator Experience comparing his understanding towards the system. According to the operation rule-based, fuzzy logic was able to process the information input immediately and also able to generate the necessary output. However, defining the rule-based quickly becomes complex if too many input and output are chosen. Depending on the system, the assessment of each possibility input might be not necessary if this very seldom or never occur. By using the fuzzy clustering algorithm, membership function could be counted based on two possible clustering methods. First, fuzzy clustering method performed in the orthogonal axis manner; the multivariable membership can be projected to one dimensional fuzzy sets. The second method is by using antecedent multi dimension membership function similar to the fuzzy cluster performed into input area. The basic idea in this paper work is how to learn and generate the optimum rules that required controlling input without decreasing the control quality. The subtractive clustering method to generate fuzzy logic rules on Takagi-Sugeno-Kang (TSK) fuzzy system has been utilized in this study. The suggested fuzzy logic is a smart technique which is applied into urban smart-traffic. This technique combined with neural network and genetic algorithm to determine the signal timing and offset time at Bandar Baru Bangi traffic junction control system. Based on the study, it is found that the system was able to generate 8 cluster center at on 30(3×10) data value at 0.3 cluster radius and also able to generate 4 cluster center at 0.5 radius with average MSE of 0.005.
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6. Role of Cu-Mfi Zeolite Catalyst on Direct Conversion of Methane Ethane to Gasoline
Norzita Ngadi, Nor Aishah Saidina Arnin & Didik PrasetyokoAbstract
HZS’M-5 (Si/Al = 30), silicalite and Cu-MFI with different copper concentrations were synthesized by direct synthesis method. The catalyst samples were characterized using X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR) and Temperature Programmed Desorption of Ammonia (TPD-NH3) techniques. The catalytic performance of the samples was evaluated in a continuous micro packed-bed reactol: The reaction was performed at reaction temperature 800°C under atmospheric pressure. The effects of Cu content on methane conversion and products selectivity were investigated. Characterization results revealed that the samples were MFI-zeolite catalysts and the copper species most probably occluded in the defect sites of the zeolite. Modification of zeolite with copper resulted in the enhancement of methane conversion up to 15 %. The experimental results using Cu(O.I)-MFI demonstrated a high selectivity to gasoline, which is 29.7%
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7. Fatigue Data Editing Algorithm for Automotive Applications
Shahrum Abdullah, John R. Yates & Joseph A. GiacorninAbstract
This paper presents a wavelet based algorithm to summarise a long record of fatigue signal by extracting the bumps (fatigue damaging events) to produce a bump signal. With this algorithm the input signal is decomposed using the orthogonal wavelet transform and the wavelet levels are then grouped into characteristic frequency bands. Bumps are extracted from each wavelet group at a specific trigger level, which is set automatically according to the global signal statistics comparison between the original and bump signals. The accuracy of the algorithm has been evaluated by application to two experimentally measured data sets containing tensile and compressive preloading conditions. For both data sets, the bump signals length were at minimum of 40% of their respective original signals, and almost 90% original fatigue damage was retained in the bump signals, as calculated using the strain-life models of Smith-Watson- Topper and Morrow. Based on the results, this algorithm was found to be a suitable approach to summarise a long fatigue signal for the automotive usage.
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8. An Expert System to Design Composting Facilities for Municipal Solid Waste
Noor Ezlin Ahmad Basri, Hassan Basri & E.I. StentiforAbstract
An expert system prototype, Compost Design Consultant (CDC), was developed to aid the preliminary design of composting facilities for municipal solid waste. The prototype development process for the CDC adopted a modular approach, which covered the main design tasks for the selected composting system. These covered,’ the reception facilities, the materials handling equipment, the storage facilities, pretreatment processes, feedstock conditioning, composting process control, post treatment processes, site requirements, operational considerations, market planning and environmental considerations. An expert system shell, Kappa-pc (version 2.1), was preferred as the building tool for the development of the prototype because of its object-oriented approach that combines the two main knowledge representation techniques, i.e. production rules and objects. It was also found to offer advantages with respect to ease of manipulation, increased productivity and a true windowing capability to run on personal computers. The main issues addressed in the expert system development were the knowledge acquisition process and the building of the prototype. The major steps involved were problem definition, implementation and testing. The knowledge used in the system was acquired from many sources such as textbooks, manuals and guidelines, journals, reports, case studies and domain experts. In the CDC consultation process, the user can evaluate the most suitable composting system for a particular site based on local conditions, and other design requirements for the facility. A summary of the system’s recommendations and additional information on the Composting System Module was shown as an example to evaluate the performance of CDC consultation process, which was considered satisfactory. The primary , end-users of the CDC would be consulting engineers, waste management engineers, recycling coordinators, municipal managers and decisions-makers, who would use it as an aid to their decision making process.
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9. A Computer Integrated Manufacturing System for Low Repetitive and High Product-Mix Components
Ginting A. & Che Hassan Che HaronAbstract
This paper describes a strategy to fulfill the needs of the 21st century metalworking industry, especially for the industry that produces the low repetitive and high product-mix components using machining centres. The approach of strategy is emphasized in developing of computer integrated manufacturing (CIM) software technology. The designed software comprises of computer aided design (CAD) and computer aided manufacturing (CAM) modules, which is supported by common and working databases, run through dialogue box as the primary user inteiface inside AutoCAD’, and
written in ARX (AutoCAD’ Runtime eXtension, the C++ Application Programming Interface to AutoCAD). The CAD module provides user with capabilities of designing product model by feature-based design and obtaining product data. The product model is displayed on screen in AutOCAD environment, while the product data is maintained by the Database Management System (DBMS) before transferring it downstream to CAM module. The Structured Query Language (SQL) is used to link the CAM module to DBMS to provide a two-way flow data. Finally, the product data is entered to CAM module for process planning purposes, which is supported by machine tool and fixture databases. The ultimate goal of the software is to solve the CAD, computer aided process planning (CAPP), CAM integration and operation planning that consists of machining data generation and tool selection from the tool database, and NC program generation.
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10. Teknik Penderiaan Jauh dalam Kajian Sedimen Terampai di Muara Sungai Langat (Remote Sensing Technique in Study of Suspended Sediment in Sungai Langat Estuary)
Suraya Sharil, Othman A. Karim & Sharifah Mastura Syed AbdullahAbstract
This study examines the sediment plume behaviour entering the sea using the physical model and remote sensing techniques. This paper will only discuss the application of remote sensing in suspended sediment study at Sg. Langat estuary. CIMEL radiance meter was used as a sensor to record optical data (digital count value or DN) from the simulation of the sediment plume dispersion in the model. This study observes the relationship between the DN obtained with the suspended sediment concentration. Results from correlation analysis show that the relation between DN and sediment plume concentration in the lab is most significant and strong at 0.85 μm wavelength, and the weakest relation is in the 0.45 μm wavelength. Small water particles from the wave generation were identified as one of the most important atmospheric disturbance to optical data, especially for shorter wavelength i.e. 0.45 μm. Beside that, water roughness and additional illumination from the 1000 watt spotlight also affect the DN values obtained. Water roughness has caused the increase in the DN value, while illumination from spotlight has caused a shift in the peak of spectral signature to longer wavelength, i.e. 0.85μm
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