Skip Navigation LinksVolume : Volume 15 No.2 2006

activity_and_deactivation_of_cr_cu_modified_zsm-5_catalyst_in_the_combustion_of_chlorinated_volatile_organic_compounds.pdfACTIVITY AND DEACTIVATION OF Cr-Cu/MODIFIED ZSM-5 CATALYST IN THE COMBUSTION OF CHLORINATED VOLATILE ORGANIC COMPOUNDS
ABSTRACT : The performance of chromium-copper supported over H-ZSM-5 (Si/Al=240) modified with silicon tetrachloride (Cr1_0Cu0/SiCl4-Z) as the catalyst in the combustion of chlorinated VOCs (CI-VOCs) is reported. A reactor operated at gas hourly space velocity (GHSV) 32,000 h·1, temperature between 100 and 500°C with 2,500 ppm of dichloromethane (DCM), trichloromethane (TCM) and trichloroethylene (TCE) were used for activity studies. Deactivation study was conducted at GHSV 3,800 h-1 at 400°C for up to 12 h with a feed concentration of 35,000 ppm. TCM was more reactive compared to DCM but it produced more chlorinated byproducts due to its high chlorine content. The stabilisation of TCE was attributed to the resonance effects. The residual activity of this catalyst stabilised at between 88-92%, depending on feed compounds. Deactivation of Cr1_0Cu0/SiCl4-Z was mainly due to the chlorination of its metal species, especially with higher CI/H feed. Coking activity of this catalyst was low particularly with DCM and TCM. In accordance with Mars-van Krevelen model, the weakening of overall metal reducibility due to chlorination led to loss of activity. KEYWORDS : CI-VOC, deactivation, reducibility, ZSM-5, bimetallic, SiCl4 77 Author: Ahmad Zuhairi Abdullah*, Mohamad Zailani Abu Bakar and Subhash Bhatia
20063/14/2017 12:27 PM3/28/2017 2:51 PM
application_of_cad_and_sla_for_design_and_development_of_titanium_mesh_implants.pdfAPPLICATION OF CAD AND SLA FOR DESIGN AND DEVELOPMENT OF TITANIUM MESH IMPLANTS
ABSTRACT : The use of CAD and Rapid Prototyping in surgery has benefited both surgeons and patients. 20 image data of patients is converted to 3D CAD data for further manipulation and anatomic models produced by rapid prototyping technique provide tactile information that can be used by surgeons to diagnose and plan the treatment and surgical operation. A case study of the application of CAD and RP for design and fabrication of implant used in craniofacial surgery is described. The result of this process is the production of a mould that is used to press form titanium mesh into a ready to use implant, which fits nicely to the patient. The approach has increased the effectiveness and productivity of surgeons as well as improved the overall surgery time. KEYWORDS : CAD, Rapid Prototyping, Stereolithography, Craniofacial, Surgery, Titanium Mesh Implant Author: Wan Abdul Rahman Wan Harun, Victor Devadass, lzhar Abdul Aziz
20063/14/2017 12:27 PM3/28/2017 2:52 PM
a_5.7_ghz_variable-gain_low_noise_amplifier_vglna_for_low_voltage_applications.pdfA 5.7 GHZ VARIABLE-GAIN LOW NOISE AMPLIFIER (VGLNA) FOR LOW VOLTAGE APPLICATIONS
ABSTRACT : A low voltage topology that uses a capacitively coupled resonating element has been introduced in the ever demanding radio frequency (RF) designs. The topology utilises the decoupling scheme to de isolate circuit elements that are connected in series and share a common de current. A 5.7 GHz 0.18 µm CMOS variable-gain low noise amplifier (VGLNA) is used to realise the topology. Simulation shows promising results with the VGLNA exhibiting a noise figure of 1.02 dB, power gain of 19.41 dB, IIP3 of -1.11 dBm and gain tuning range of 6 dB. The power consumption reported is 12.88 mW at supply of Vdd = 0. 7 V.A comparison is made between a low voltage cascode VGLNA and the classic cascode VGLNA. The results show that the low voltage cascode VGLNA performs better in most areas. KEYWORDS : capacitively coupled, linearity, low voltage, power optimisation, variable-gain low noise amplifier Author: Lini Lee, S.S. Jamuar, Roslina Mohd Sidek and Sabira Khatun
20063/14/2017 12:27 PM3/28/2017 2:50 PM
direct_measurement_of_powder_cohesion.pdfDIRECT MEASUREMENT OF POWDER COHESION
ABSTRACT : Cohesion is a physical property that best describes the flowability of powder which aids in storage, handling and processing of powders. In this study cohesion values are measured and correlated with other established flowability indicators such as angle of repose and Hausner ratio. A series of mixture of fine and coarse sand composition were employed with sauter diameters of 15.21 µm and 636.80 µm respectively. Warren-Spring-Bradford Cohesion Tester (WSBCT) used for direct measurement was found to be simpler and time saving compared to the conventional indirect method of the Jenike Shear Cell. Cohesion value and penetration strength were measured with the WSBCT. Established flowability indicators, i.e. Hausner ratio and angle of repose were measured separately. It was found that a particle size of 45 µm is critical in determining the cohesivity of powders. Cohesion values correlated well with other known flowability indicators. However, the penetration strength was found to be a poor flowability indicator for the fine powders used. Recommendations are proposed on how to further investigate the penetration strength of fine powders. KEYWORDS : Cohesion, powder, flowability 151 Author: Aziz A.R. and E.C. Abdullah
20063/14/2017 12:27 PM3/28/2017 2:52 PM
effect_of_al2o3_addition_in_the_hand_former_composition_on_chemical_resistance.pdfEFFECT OF Al 20 3 ADDITION IN THE HAND FORMER COMPOSITION ON CHEMICAL RESISTANCE
ABSTRACT : Ten compositions of hand former body were prepared with different alumina content from 1% to 45% to determine the effect of acid and alkali resistance. The compositions containing alumina between 20% to 25% showed good resistance to acid and alkali. The acid resistance (body corroded by acid) is between 16-20 x 10-3 g/cm 2 and the alkali resistance is between 180 - 210 x 1Q-3 g/cm 2• The body was matured at 1250°C for 30 minutes at the firing rate of 3°C/minute. KEYWORDS : Hand former, chemical resistant, acid resistant, alkali resistant Author: Jaafar Abdullah
20063/14/2017 12:27 PM3/28/2017 2:56 PM
implementation_of_process_quality_module_pqm_in_fan_and_blower_plants_shop_floor_reengineering.pdfIMPLEMENTATION OF PROCESS QUALITY MODULE (PQM) IN FAN AND BLOWER PLANT'S SHOP FLOOR REENGINEERING
ABSTRACT : The process quality module (PQM) was used to investigate the flow of production and the incorporated quality shortcomings in fans and blowers industry. PQM contains seven modules and it outlines all the approaches needed for reengineering . The first three steps are initialisation steps designed to be executed infrequently. The first step is to identify process, technology, and tasks being performed. The next step is to identify the customers and their requirements, expectations, and perceptions. The third is to define quality as it pertains to the process of interest. The last four steps of the PQM are designed to facilitate continuous improvement and process control, and thus they are executed frequently. It starts by identifying quality performance measures. Evaluation of the current process and setting of quality standards is followed by the improvement of the process. Finally the process must be controlled and monitored. PQM approach is interpreted for this industry and necessary modifications are made. The steps and methods used to implement are discussed and recorded . KEYWORDS : Process quality module, fan and blower, reengineering Author: K.W. Rao, M. Y. Ismail, M. M. Hamdan, N. Ismail, S.M. Sapuan and V. Mariappan
20063/14/2017 12:27 PM3/28/2017 2:56 PM
implementing_iso_14000_the_key_to_greening_of_malaysian_industry.pdfIMPLEMENTING ISO 14000: THE KEY TO GREENING OF MALAYSIAN INDUSTRY
ABSTRACT : Throughout the world today, the approach is for industries and governments to respond to increasing public concern on the environment by adopting appropriate policy and framework for environmental protection. The emergence and implementation of the ISO 14000 series of standards impose additional costs and generate new opportunities for Malaysian industries which could change the competitive climate that faces them in this era of globalisation. The survival and success in the marketplace is linked to the ability of our Malaysian industries to be flexible and be able to respond to new pressures before them. This paper highlights the benefits of adopting and implementing the ISO 14000 series of standards where Malaysian industries could make efforts towards environmental improvement and enhance performance. KEYWORDS : Environmental management, greening Malaysian industry, sustainable development environmental management systems, ISO 14000 Author: Sumiani Yusoff, PhD.
20063/14/2017 12:28 PM3/28/2017 2:57 PM
mechanism_of_grain_growth_in_an_aerospace_aluminum_alloy.pdfMECHANISM OF GRAIN GROWTH IN AN AEROSPACE ALUMINUM ALLOY
Abstract : Annealing heat-treatments experiments in the temperature range of 200-250°C for durations in the range of 20 min - 22h for the aerospace aluminum alloy have been conducted. The material processing resulted in grain growth in the microstructure of the alloy. The grain size data have been plotted versus time at various temperatures; and the graphical plots have been analysed to establish the effects of annealing time and temperature on grain size. A distinction between normal and abnormal grain growth has been made to study the mechanism of the grain growth processes. The rates of grain growth at various grain diameters have also been computed at various temperatures and graphically analysed to establish the kinetic aspects of grain growth in the aerospace aluminum alloy. Keywords : 2024-T3 aluminum alloy, grain growth, kinetics, normal and abnormal grain growth Author: Zainul Huda, Mohammad Saufi and Shaifulazuar
20063/14/2017 12:28 PM3/28/2017 2:57 PM
metals_in_medical_and_dental_surgery.pdfMETALS IN MEDICAL AND DENTAL SURGERY
ABSTRACT : Metals have been successful biomaterials for many years, especially for medical and dental surgery purposes. The most common metals are stainless steel, cobalt-chromium alloys, and titanium and its alloy. The mechanical properties of the materials are of great importance when designing load-bearing implants. The properties of the implants depend not only on the type of metal but also on the process used to fabricate the material and device. In addition, its must be either noble or corrosion-resistant to the body environment. The purpose of this contribution is to briefly discuss their properties, compositions, processing and applications. KEYWORDS : Metal implant, titanium, stainless steel, cobalt chrome Author: Mohmad Soib bin Selamat
20063/14/2017 12:28 PM3/28/2017 2:58 PM
practice_of_critical_factors_for_business_survival_and_competitiveness_in_malaysian_manufacturing_smes.pdfPRACTICE OF CRITICAL FACTORS FOR BUSINESS SURVIVAL AND COMPETITIVENESS IN MALAYSIAN MANUFACTURING SMEs
ABSTRACT : This paper is based on a survey conducted in 2003 on top management's practice of critical factors for business survival and competitiveness in the Malaysian automotive components manufacturing SMEs. The main objective of this paper is to provide empirical evidence on top management's practices of the critical factors. To achieve this objective, the authors developed a questionnaire comprising four major critical factors and 53 elements that was checked for reliability and validity by experts and practitioners. The analyses from 68 respondent companies showed overall, there are some very important factors that could influence the SMEs competitive performance relative to competitors and their goals to survive, stay competitive and prosper. The paper also discusses the critical factors, major problems and obstacles for implementing benchmarking activities. Finally, the paper concludes with some suggestions on steps to improve the adoption and practice of critical factors for improving business performance and competitiveness in Malaysian SMEs. KEYWORDS : Business competitiveness, survey, critical factors, customer satisfaction, and SMEs Author: Baba Md Deros, Sha\'ri Mohd Yusof and Azhari Md Salleh
20063/14/2017 12:28 PM3/28/2017 2:58 PM
preliminary_studies_on_the_heat_treatment_processes_for_pan_carbon_fibre.pdfPRELIMINARY STUDIES ON THE HEAT TREATMENT PROCESSES FOR PAN CARBON FIBRE
ABSTRACT : This paper reports the preliminary studies of pre-stabilisation and stabilisation processes in the production of PAN carbon fibre. The pre-stabilisation process involves immersion of PAN precursor in potassium permanganate (KMn04), dimethylformamide (DMF) and aluminium chloride (Al2Cl6) at 85°C in which a promising catalytical behaviour is demonstrated through the characterisation techniques used. The Fourier Transform Infra Red (FTIR) spectra indicate a distinctive nitrile group of C=N at 2350 cm-1 and a decrease of C=N group at 2244 cm-1 during pre-stabilisation process. This is due to the formation of a ladder polymer which occurs intermolecularly or intramolecularly during cyclisation process. Thermal analysis supports this view as the pre-treated PAN fibre showed a reduced activation energy, earlier onset cyclisation temperature and higher degree of cyclisation reaction through its heat flow. Similarly, stabilisation at 200°C also indicates chemical structural changes through cyclisation process. Various competing reactions took place during stabilisation. Cyclisation results in the release of a few gaseous species such as HCN and C02 while oxidation possibly results in the absorption of O2 into the PAN precursor backbone. KEYWORDS: PAN carbon fibre, pre-stabilisation, thermal stabilisation, heat treatment Author: M.A. Baharom, S. Shamsuddin, I. Mustafar, K. Noorsal, I. Ahmad, H.F.A. Marzuki
20063/14/2017 12:28 PM3/28/2017 3:01 PM
studies_on_metal_leachability_and_alkalinity_of_leachates_from_cement_stabilised_contaminated_soils.pdfSTUDIES ON METAL LEACHABILITY AND ALKALINITY OF LEACHATES FROM CEMENT STABILISED CONTAMINATED SOILS
ABSTRACT : This paper presents the findings on zinc and lead leachabilty as well as alkalinity of leachates from cement stabilised contaminated soils. The Toxicity Characteristic Leaching Procedure (TCLP) and Synthetic Precipitation Leaching Procedure (SPLP) have been performed on the solidified/stabilised contaminated soils of which zinc and lead concentrations and alkalinity of the resultant leachates are determined. Results indicate that cement shows excellent treatment effectiveness for stabilising metal contents in contaminated soil. It has also been determined that the residual blocks of stabilised contaminated soil present in unfiltered leachates provide additional acid buffering capacity to the leachates, reducing the leached concentrations of zinc and lead. KEYWORDS : pH, alkalinity, solidification/stabilisation, lead, zinc, cement Author: Yin Chun-Yang, Hilmi Bin Mahmud and Ghazaly Shaaban
20063/14/2017 12:28 PM3/28/2017 3:01 PM
voltage_sag_mitigation_due_to_starting_of_an_induction_motor_load.pdfVOLTAGE SAG MITIGATION DUE TO STARTING OF AN INDUCTION MOTOR LOAD
ABSTRACT : Power quality is one of the most talked about topics these days. Both the power utilities and customers are quite concerned with the quality of the power supply, whether it be the power generated by the power utilities or the power consumed by the customers respectively. They need these supplies to be at its optimum value so that the cost is efficient; otherwise problems such as overvoltage, undervoltage, voltage swell, voltage sag, noise and harmonic caused by the disturbances in power supply could be disastrous. This paper investigates the static synchronous compensator (STATCOM) behaviour for voltage sag mitigation due to starting of an induction motor. Simulation of STATCOM based on 6 pulses 3-phase voltage source inverter (VSI) using Matlab Simulink has been developed to show its performance under balanced voltage sag condition due to starting of 5 KW 3-phase induction motor. Experimental testing has been constructed using 3-phase thyristor natural commutation bridge. An improvement of more than 11% of the voltage sag has been achieved using the STATCOM which can respond instantaneously to compensate reactive power to the system during voltage sag. Finally simulation results and experimental results have been explained and compared, and a good performance has been obtained. KEYWORDS : Voltage sag, sag mitigation, STATCOM, Var compensation Author: S.M. Bashi, N. Mariun, N.F. Mailah, A.F. Huweg
20063/14/2017 12:28 PM3/28/2017 3:00 PM