Jaffar Syed Mohamed Ali

Stability and Takeoff Ground Roll Issues of Hybrid Buoyant Aircraft

In the field of aviation it is well known that a vehicle’s stability and takeoff flight segment are critical. This issue becomes more critical for a hybrid aircraft which is concealed as an airship with huge volume of hull as compared with fuselage of a conventional aircraft. In the present work, stability issues of a generic model of airship and of a conceptual model of hybrid aircraft are discussed. Special emphasis is given for future sizing of empennages of IWHA-14, a hybrid aircraft concept proposed for Malaysian inter island transportation. Effect of gondola position on rotation angle for takeoff ground roll was analyzed and it was found that such configurations can meet the requirement of minimum roll angle.

Medical genetics in developing countries in the Asia-Pacific region: challenges and opportunities

Advances in genetic and genomic technology changed health-care services rapidly in low and middle income countries (LMICs) in the Asia-Pacific region. While genetic services were initially focused on population-based disease prevention strategies, they have evolved into clinic-based and therapeutics-oriented service. Many LMICs struggled with these noncommunicable diseases and were unprepared for the needs of a clinical genetic service. The emergence of a middle class population, the lack of regulatory oversight, and weak capacity-building in medical genetics expertise and genetic counseling services led to a range of genetic services of variable quality with minimal ethical oversight. Some of the current shortcomings faced include the lack of awareness of cultural values in genetic health care, the variable stages of socioeconomic development and educational background that led to increased demand and abuse of genetics, the role of women in society and the crisis of gender selection, the lack of preventive and care services for genetic and birth defects, the issues of gene ethics in medicine, and the lack of understanding of some religious controversies. These challenges provide opportunities for both developing and developed nations to work together to reduce the inequalities and to ensure a caring, inclusive, ethical, and cost-effective genetic service in the region.

Hybrid Buoyant Aircraft: Future STOL Aircraft for Interconnectivity of the Malaysian Islands

Hybrid buoyant aircraft are new to the arena of air travel. They have the potential to boost the industry by leveraging new emerging lighter-than-air (LTA) and heavier-than-air (HTA) technologies. Hybrid buoyant aircraft are possible substitutes for jet and turbo-propeller aircraft currently utilized in aviation, and this manuscript is a country-specific (Malaysia) analysis to determine their potential market, assessing the tourism, business, agricultural, and airport transfer needs of such vehicles. A political, economic, social, and technological factors (PEST) analysis was also conducted to determine the impact of PEST parameters on the development of buoyant aircraft and to assess all existing problems of short takeoff and landing (STOL) aircraft. Hybrid buoyant aircraft will not only result in reduction of transportation costs, but will also improve the economic conditions of the region. New airworthiness regulations can lead to greater levels of competition in the development of hybrid buoyant aircraft.

Effect of stitching on the tensile mechanical property of empty fruit bunch oil palm fiber reinforced epoxy composites

Stitching has proven to be an effective reinforcement for improving through-thickness (out-of-plane) mechanical properties with the incorporation of z-direction reinforcements of synthestic fiber. There are drawbacks to stitching as it may cause focal stress concentration, and fiber misalignment and breakage, but at the same time, it can also improve the tensile performance of the composite. Tensile properties, such as tensile strength and modulus of elasticity, were obtained from tensile tests performed on both stitched and unstitched oil palm fiber composites as per ASTM D638 specifications using Universal Testing Machine INSTRON 5582. The test results indicated that stitching natural, short, untreated and random empty fruit bunch oil palm fiber reinforced epoxy composites improve the tensile strength and elastic modulus due to the increase in matrix volume percentage and additional tensional resistance.

Numerical investigation of aerodynamic characteristics of high speed train

In this work, initially the effect of nose shape on the drag characteristics of a high speed train is studied. Then the influence of cross winds on the aerodynamics and hence the stability of such modern high speed trains is analyzed. CFD analysis was conducted using STAR-CCM+ on trains with different features and important aerodynamic coefficients such as the drag, side force and rolling moment coefficients have been calculated for yaw angles of crosswinds ranging from 0° to 90°. The results show that the modification on train nose shape can reduce the drag up to more than 50%. It was also found that, bogie faring only reduces small percentage of drag but significantly contributed to higher rolling moment and side force coefficient hence induced train instability.

Study on the effect of window opening on the drag characteristics of a car

In this study, the effect of window opening on the drag characteristics of a car is investigated. This additional aerodynamic drag can considerably affect the performance of a car in terms of instability, noise and fuel consumption. Using a 3D car model, the effect of window opening on the drag characteristics was numerically studied using STAR–CCM+ commercial CFD software. It was observed that the aerodynamic drag is highly influenced by the different window openings. For validation, a scaled down car model was tested in the IIUM low speed wind tunnel. The results obtained from both simulation and experimental data showed that the car with all windows open produced higher drag than a car with all windows closed. The experimental data from the wind tunnel test results was found to be in good agreement with the simulation counterpart for the determination of drag coefficient for both window positions.

Experimental Study of Impact on Carbon-Fiber-Epoxy Composite Wing Leading Edge Structure

This paper works on the curvature composite structure for wing leading edge application using fabric carbon/epoxy material subjected to impact loading. At first stage, rigid spherical projectile and elliptical panel with were used. The impact testing has been carried out by varying the radius of curvature, the thickness of the panel and different stacking sequence. The experimental results show the trend of specific energy absorption capability of structure in function of the radius, thickness of panel and carbon fiber directions.

Effect of Cross Sectional Shape on the Energy Absorbing Characteristics of a Tube under Quasi-Static Loading

In this study, numerical simulation of tubes of various cross section under axial compression is carried out using LS-DYNA. The effect of varying configurations of tube cross-section shape on the deformation response, collapse mode and energy absorption characteristics of tubes under quasi-static axial compression have been studied. The validation of the finite element tube model was made by comparison with the experimental results of the square tube subjected to quasi-static axial compression. Tabulated results are presented and plots have been included for the specific energy absorption for different cross sections. The study provides an insight on ways to increasing energy absorption of light weight aluminium tubes.

Educational software for stress analysis of idealized thin walled open sections

An educational software which can aid students in stress analysis of idealized thin-walled open sections has been developed. The software enables students to select different cross-sections which may be subjected to bending, shear or torsional loads and evaluate the stresses on it. Results obtained through this software have been validated. The software has been developed using MATLAB with graphical user interface (GUI). The software is expected to be a useful tool for effective teaching learning process of courses on thin-walled structures and aircraft structures.

Experimental and Numerical Simulation of Hollow Structure under Compression Loading

Buckling and crushing behaviour of hollow structure was studied through experiments and numerical simulation. The experimental material was a thin aluminium square tube (38 x 38, 1.2 mm thick). Quasi-static crushing load was applied using a Universal Testing Machine, Shimadzu Autograph (AG-X) series which uses TRAPEZIUMX software for control and data logging. Finite element simulation of the crushing test was done using LS-DYNA software. Results of the two analyses were compared and found in good agreement. The study provides an insight on ways to increasing energy absorption of light weight aluminium tubes. The simulation procedure can be used for further investigation of aluminium tubes of different cross section areas and geometries.