Mahmod Abd Hakim Mohamad

Experimental Study on Ballistic Resistance of Sandwich Panel Protection Structure with Kenaf Foam as a Core Material against Small Arm Bullet

This project is about an experimental impact resistance and behaviour of sandwich panel structure, consists of steel plates and kenaf foam. The use of natural fiber reinforcement foam could give a great advantages in weigh reduction which very useful in military mobility and transportability. A standard rifle was used to launch a small bullet (5.56 mm) in constant velocity towards the sandwich panels. The experiments result is based on the depth of the indentation due to the penetration against the armour. The best specimen combining both parameters of study is 20% of kenaf with 45 mm thickness because it can resists the most impact from the bullet. Therefore, it can be concluded that using kenaf to reinforce the polyurethane is success in enhancing its strength and mechanical properties.

Comparison of Zinc Roofed House Temperature Distribution between Open Water Exhausted with Radiator Cooling System

Thermal condition of a house is one of the comfort factors. Traditionally, village houses in Malaysia uses corrugated zinc roofing due to economic reason. Considering the thermal conductivities of the material, space under the roof coverage will intent to occur thermal discomfort due to Malaysian ambient temperature. The roof plays an important role to ensure the house is in a state insulated from the hot sun and rain where the zinc roofing will radiated by the sun in noon and yet become the heat source for in-house area. Thermal discomfort will result due to zinc highly heat absorbing material property. The space under the covering will experience significant temperature increase proportional to the amount of supplied heat from sunlight radiated to the zinc roof, and will further be aggravated if ventilation is poor. The purpose of this study is to compare the temperature distribution by two alternatives methods to reduce the temperature inside a zinc-covered house. The main concept of this cooling system is by splashing water throughout the area of the zinc roofing, where heat exchange process will occur upon contact. The process will dissipate heat from the zinc and will increase the water temperature. This research is focusing on the medium (water) re-cooling process by either open water exhausted or radiator system to state that which one will give better heat exchange. Open water exhausted system heated water will then free fall by gravity into a tank through perforated tube as water droplets. To facilitate higher rate of water-cooling, fan will be provided. Another re-cooling system is the radiator system, which use radiator device to cool down the heated water. Radiator use coolant as the medium to exchange the heat from the roof heated water. By the same heat transfer process, the circulated water temperature will be lower where, which will be recirculation back to the roof. Both systems had been compared about the differences of temperature drop distribution which result the better water re-cooling system.

Dry Sliding Wear Behavior of the Reinforced by Graphite Particle and Heat Treated of Recycled Aluminum AA6061 Based MMC Fabricated by Powder Metallurgy Method

The micro-hardness and compression of recycling aluminum alloy AA6061 were investigated as a function of the different microstructure and constituent powder metallurgy method. Five specimens were selected to investigate the compression strength and microhardness. The first, as fabricated specimen (as compacted), the second was as heat treated by quenching and aging process. Three specimens were mixed with Graphite particles as a reinforcement material. Compression strength values were tested for the specimens as fabricated and heat treated which were 195 and 300 MPa, respectively. The improvement ratio was 52% for the specimen as heat treated. On the other hand, high wear resistance was given by the specimen as heat treated, whereas, the lower wear strength was at the specimen mixed with 4.5% Graphite. These results were attributed to that the wear resistance related to the microhardness value.

An Overview of Cloud Implementation in the Manufacturing Process Life Cycle

The advancement of information and communication technology (ICT) has changed the structure and functions of various sectors and it has also started to play a significant role in modern manufacturing in terms of computerized machining and cloud manufacturing. It is important for industries to keep up with the current trend of ICT for them to be able survive and be competitive. Cloud manufacturing is an approach that wanted to realize a real-world manufacturing processes that will apply the basic concept from the field of Cloud computing to the manufacturing domain called Cloud-based manufacturing (CBM) or cloud manufacturing (CM). Cloud manufacturing has been recognized as a new paradigm for manufacturing businesses. In cloud manufacturing, manufacturing companies need to support flexible and scalable business processes in the shop floor as well as the software itself. This paper provides an insight or overview on the implementation of cloud manufacturing in the modern manufacturing processes and at the same times analyses the requirements needed regarding process enactment for Cloud manufacturing and at the same time proposing a STEP-NC concept that can function as a tool to support the cloud manufacturing concept.

Development of STEP-NC Based Machining System for Machining Process Information Flow

To realize the STEP-NC based machining system, it is necessary to perform machining feature extraction, generating machine-specific information, and creating a relationship between STEP-NC entities. A process planning system of a STEP-NC information flow that starts with constructing a machining feature from a CAD model will be developed. In this paper, a further in-depth study of the implementation and adaptation of STEP-NC in manufacturing is studied. This study will help to understand how the data from CAD/CAM can be converted into STEP-NC codes and the machining process will be based on the STEP-NC codes generated.

One-dimensional high-order compact method for solving Euler's equations

In the field of computational fluid dynamics, many numerical algorithms have been developed to simulate inviscid, compressible flows problems. Among those most famous and relevant are based on flux vector splitting and Godunov-type schemes. Previously, this system was developed through computational studies by Mawlood [1]. However the new test cases for compressible flows, the shock tube problems namely the receding flow and shock waves were not investigated before by Mawlood [1]. Thus, the objective of this study is to develop a high-order compact (HOC) finite difference solver for onedimensional Euler equation. Before developing the solver, a detailed investigation was conducted to assess the performance of the basic third-order compact central discretization schemes. Spatial discretization of the Euler equation is based on flux-vector splitting. From this observation, discretization of the convective flux terms of the Euler equation is based on a hybrid flux-vector splitting, known as the advection upstream splitting method (AUSM) scheme which combines the accuracy of flux-difference splitting and the robustness of flux-vector splitting. The AUSM scheme is based on the third-order compact scheme to the approximate finite difference equation was completely analyzed consequently. In one-dimensional problem for the first order schemes, an explicit method is adopted by using time integration method. In addition to that, development and modification of source code for the one-dimensional flow is validated with four test cases namely, unsteady shock tube, quasi-one-dimensional supersonic-subsonic nozzle flow, receding flow and shock waves in shock tubes. From these results, it was also carried out to ensure that the definition of Riemann problem can be identified. Further analysis had also been done in comparing the characteristic of AUSM scheme against experimental results, obtained from previous works and also comparative analysis with computational results generated by van Leer, KFVS and AUSMPW schemes. Furthermore, there is a remarkable improvement with the extension of the AUSM scheme from first-order to third-order accuracy in terms of shocks, contact discontinuities and rarefaction waves.