Skip Navigation LinksVolume : Volume 15 No.1 2006

effects_of_shear_stress_and_shear_time_on_rheological_properties_of_zeolites.pdfEFFECTS OF SHEAR STRESS AND SHEAR TIME ON RHEOLOGICAL PROPERTIES OF ZEOLITES
ABSTRACT : The rheological properties of dry powders dispersed in liquid enable prediction of microstructure and ease of dispersion of the powders in slurry form. This paper highlights the differences in the rheological roperties of various zeolite powder with similar size range of 3.9 - 4.6 µm when subjected to constant shear stress of 0.85 - 8 Pa and shearing time of 720 s. When the value of the imposed shear stress increased , the viscosity of zeolite vegabond ZVXD decreased with increasing shear rate. As for zeolite doucil P, ZDP, the critical shear stress where the viscosity level was inverted, occurred at 7 Pa. In the case of zeollite wessalith P (ZWP), there was no s ignificant reduction of viscosity of ZWP dispersions at low shear stress times as seen in the profiles of ZVXD and ZDP. Knowing viscosity profiles can lead to better formulation of detergents where zeolite powders are the active ingredients. In addition, the characteristics of structural breakdown could be made from the generated viscosity curves. It was found that the rheological properties of zeolites with similar size range differs when subjected to constant shear stress and shearing time. The viscosity curves of standard ized dispersion were studied using Carrimed CSL 100, a controlled stress rheometer. KEYWORDS : Rheology, zeolite, controlled stress rheometer, microstructure Author: Suzana Yusup, Suriati Sufian and Khalik M Sabil
20063/14/2017 12:26 PM3/28/2017 3:03 PM
electronic_control_unit_for_vehicles_issues_and_the_way_forward.pdfELECTRONIC CONTROL UNIT FOR VEHICLES: ISSUES AND THE WAY FORWARD
ELECTRONIC CONTROL UNIT FOR VEHICLES: ISSUES AND THE WAY FORWARD ABSTRACT : The latest generations of road vehicles have seen a tremendous development in onboard electronic system, which controls increasingly large parts of the vehicle's functionality. The automotive electronic revolution has significantly improved the performance, reliability and comfort of the automobile. Electronic Control Unit (ECU) is a system that plays a more and more important role in the development of road vehicles. The increasing complexity and stringent quality and cost requirements mandate tremendous improvements in all aspects of specification and design process. This paper discusses the overall aspects of the new era of ECU, issues in emission regulations, algorithms and communications are addressed. KEYWORDS : ECU, ECM, EFI, automotive, engine control Author: Ibrahim Mat, Ishak Aris, Mohd Khair Hassan, Roslina Mohd Sidek, Nik Anis Alina Nik Othman and Syed Malek Faisal
20063/14/2017 12:26 PM3/28/2017 3:04 PM
fatigue_mechanism_of_semi-metallic_brake_pads_during_braking_process.pdfFATIGUE MECHANISM OF SEMI-METALLIC BRAKE PADS DURING BRAKING PROCESS
ABSTRACT : Fatigue wear mechanism was found to operate during braking process both during intermittent and continuous braking modes. In this study, a pair of brake pads was pressed against a rotating cast iron brake disc at a constant rotating speed of 750 rpm, simulating braking condition. In the intermittent braking test mode, the test samples were subjected to an applied load of 600 N for four different total braking times (400, 800, 1200 and 1600 seconds). The brake was applied for four different times (5, 10, 15 and 20 seconds) for 80 times with idling 5 seconds between each braking. Whereas, in the continuous braking, the test samples were subjected to five different braking times (180, 360, 540, 720 and 900 seconds) and applied loads (100, 200, 400, 600 and 800 N). The microstructural changes on the wear surface were observed using Scanning Electron Microscopy (SEM). Microstructural examinations showed that the fatigue mechanism started with the generation of plastic deformation in the subsurface of the brake pads. As the braking time increased, the above phenomena caused the formation of striations on the worn surface of the brake pad. With subsequent braking, the fatigue mechanism was observed to nucleate at areas where pits and spalls were present. Finally, the wear fragments were disposed from the worn surface. KEYWORDS: Brake pad, striation, microcrack, fatigue, wear Author: R.J. Talib, A. Muchtar and C.H. Azhari
20063/14/2017 12:26 PM3/28/2017 3:05 PM
metal_injection_moulding_an_advanced_processing_technology.pdfMETAL INJECTION MOULDING : AN ADVANCED PROCESSING TECHNOLOGY
ABSTRACT: The emphasis on miniaturisation, design flexibility, broad based applications and low cost has been stretching the capabilities of conventional manufacturing routes to the limit. An example of a new approach to meeting such challenges has been the development of Metal Injection Moulding (MIM). MIM is a growing advanced technology with the ability to produce large numbers of small complex near net shape parts from different metals and alloys at cost lower than machined parts. This process technology is an elegant blend of plastic injection moulding, based on the use of fine powder particles and the application of polymer science and conventional powder metallurgy, which delivers structural materials using a forming technology previously restricted to polymers. This paper discusses some of the basic MIM processes and applications. Attention is also given especially to recent MIM developments in SIRIM Berhad including the MIM facilities and research projects. KEYWORDS : Metal injection moulding, mixing, debinding, sintering Author: Mohd Afian Omar and Rosdi Ibrahim
20063/14/2017 12:26 PM3/28/2017 3:05 PM
pembangunan_laman_pelayan_aktif_active_server_page_untuk_pemaparan_maklumat_satelit_gps.pdfPEMBANGUNAN LAMAN PELAYAN AKTIF (ACTIVE SERVER PAGE) UNTUK PEMAPARAN MAKLUMAT SATELIT GPS
ABSTRACT: Active Server Page (ASP) Script by Microsoft can be used to retrieve, process, and transmit information to users through web pages as normal HTML (HyperText Markup Language). It is more stable and easier to develop dynamic web applications. Little time is used to maintain internet and intranet website, and it is very suitable to display current information in real time. This paper explains the application of ASP software to develop a website to display GPS information at remote locations and can be accessed locally through the website. The GPS (Global Positioning System) is made up of 24 satellites that were launched by the U.S. to transmit precise navigation information such as velocity, time, and position of receiver. The web pages software that is developed can display these information every three minutes from a GPS receiver that is located remotely and sent to the local station using modem (MOdulator and DEModulator). This navigation information is used not only for geodetic and geoinformation , but also for scientific research such as radio propagation, measurements of total electron content in the ionosphere, and so on . This ASP is used to help users retrieve precise and reliable current information speedily and with ease. KEYWORDS : Global Positioning System, GPS, remote monitoring, Active Server Page, ASP Author: Mardina Abdullah , Ahmad Faizal Mohd. Zain , Norbahiah Misran dan Desmond Koh
20063/14/2017 12:26 PM3/28/2017 3:06 PM
simulation_and_real_time_implementation_of_dc_servo_position_control.pdfSIMULATION AND REAL TIME IMPLEMENTATION OF DC SERVO POSITION CONTROL
ABSTRACT : DC motor systems are used widely in various fields of technology. They are used in power plants to generate electrical power and in industrial occupancies to furnish the required mechanical motive power to drive mechanical machinery and control various industrial processes. DC motor acts as one of the vital part, where the position control of the motor is the major part to be given attention to. Efforts made on controlling the position of DC motor result in so many types of control scheme for t he mentioned purpose. Some of these control schemes will be explained and d iscussed briefly in this st udy. More detailed discussions will be centered upon the studied controllers , which are the PID and adaptive controllers. Detailed explanation on designing the controller via SIMULINK is also presented in this study which includes the hardware configurations and software designs. Finally the designed controllers were both implemented to the real plant via a real time software. KEYWORDS : PID Controller, real time, DC servo motor, position control, simulink Author: Erny Aznida Alwi, Samsul Bahari Mohd Noor, Azura Che Soh
20063/14/2017 12:26 PM3/28/2017 3:06 PM
thermogravimetric_and_kinetic_studies_on_palm_shells.pdfTHERMOGRAVIMETRIC AND KINETIC STUDIES ON PALM SHELLS
ABSTRACT: Recently, owing to environmental and economic considerations, interest in utilising biomass for the production of energy and chemicals is increasing. Malaysia being the largest producer of palm oil has huge amount of oil palm wastes. In order to utilise these wastes efficiently, pyrolysis is emerging as a promising thermo-chemical technique. In this study, pyrolysis of oil-palm shell waste was carried out using thermogravimetric analysis (TGA). The effects of heating rate on the pyrolytic properties were investigated for palm shell powder of 300 and 600 µm partic le size. Kinetic parameters were also determined for different heating rates. This paper also describes the results from a bench-scale Circulating Fluidised Bed (CFB) test rig, installed at SIRIM Berhad, Shah Alam, suitable for gasification and combustion experiments using different biomass materials. Using this rig, a better understanding of the effect of primary flow and feeding rate on the emission behaviour was established. Experimental studies were also done to investigate the influence of temperature on pyrolysis. The concentrations of CO, NOx and C02 in the flue gas were measured. The combustion performances were evaluated by varying the primary gas flow through the CFB tubular furnace. The emission of NOx ranged from 38-75 ppm while the CO emissions were high for higher primary air flow rates. KEYWORDS: Biomass, emission, kinetics, oil palm wastes, pyrolysis, Thermogravimetric analysis (TGA) Author: Ahmad Hussain , Farid Nasir Ani, Amer Nordin Darus , Hamdan Mokhtar , Saiful Azam
20063/14/2017 12:27 PM3/28/2017 3:07 PM
the_significance_of_hydrodynamics_difference_between_rushton_turbine_and_marine_impeller_on_thekla_in_a_16_litre_bioreactor.pdfTHE SIGNIFICANCE OF HYDRODYNAMICS DIFFERENCE BETWEEN RUSHTON TURBINE AND MARINE IMPELLER ON THEKLA IN A 16-LITRE BIOREACTOR
ABSTRACT: An investigation on the significance of hydrodynamic difference between Rushton and marine impeller on the kLa in the 16-litre bioreactor was performed. By employing the static gassing out technique, the k L a values were calculated at different sets of impeller speeds and air flow rates, and at various viscosities and temperatures. The empirical correlation was employed to investigate the dependence of k L a on the specific power input and superficial air velocity. Our experimental results discovered that the Rushton turbine was more effective in gas distribution and provided a greater oxygen transfer rate than the marine impeller. KEYWORDS : Empirical relationship, stirred bioreactor, marine impeller, Rushton turbine, oxygen transfer coefficient Author: Muhd. Nazrul Hisham Zainal Alam, Firdausi Razali
20063/14/2017 12:27 PM3/28/2017 3:07 PM