Experimental analysis of mechanical properties of selected takraw balls in Malaysia

Sepak Takraw is a popular sport among the Southeast Asian countries and various brands of takraw balls are available in the local market to suit the needs of players. In this study, four different takraw balls commonly used by the Malaysian takraw players were selected for testing of mechanical properties by using compression and fatigue analysis. It was found that the GE takraw balls were more suitable to be used by Malaysian takraw players due to higher fatigue life and tensile strength. This finding is particularly useful for the local sport academy in deciding which ball is to be used in the future takraw competitions

Flat plate solar collectors and applications: a review

In this study, various methods and applications of flat plate solar collectors are discussed and pictorial representations are presented. Low temperature applications of flat plate collectors are identified in solar cooking, solar water heating, space and air heating, industrial heating plants and in agricultural produce drying processes. Basic equations, as presented by many researchers in the performances of flat plate collectors, are also presented. The review discusses the analysis of losses from flat plate collectors towards obtaining the overall heat loss coefficient which indicate the performance of flat plate collectors

Explicating mechanical and electrical knowledge for design phase of green building projects

Construction projects usually encompass numerous disciplines, requiring the integration of knowledge from civil, mechanical, electrical and other engineering domains. Some researchers contend that the integration of construction knowledge and experience at the early design phase would improve the overall project performance. Domination of tacit knowledge during design phase of building projects is the major source of knowledge flow problems between involved professionals. Therefore, this study intends to explicate the required mechanical and electrical knowledge which has to be considered during the conceptual design phase of a green building project. To fulfil this goal, a case study has been conducted to specify the entity of the required mechanical and electrical knowledge. The primary method for the data collection here is observation. Furthermore, this study employs the triangulation method in order to validate the collected data. The results contain the required mechanical and electrical knowledge which has to be considered during the conceptual design phase of a green building project

Ventilation Parameters and Thermal Comfort of Naturally and Mechanically Ventilated Offices

This paper discusses thermal comfort for a postgraduate study office room in the Mechanical Engineering Department of University Putra Malaysia (UPM), which maybe either naturally ventilated or air-conditioned. Thermal comfort variables were assessed by survey of sensation of the indoor climate. Tracer gas analysis, based on the concentration decay method, was employed to determine air exchange rate, age of air, and air exchange effectiveness (AEE). When the air conditioner was working the study office had conditions within the comfort zone of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Standard 55; and the occupants reported they were "slightly cool." Objective data analysis showed that the office was thermally comfortable. Under naturally ventilated conditions objective results showed that the office was uncomfortable but a subjective study revealed that students found the conditions to be "slightly warm." The neutral temperature showed a wider thermal comfort range for Malaysian students than that suggested by ASHRAE Standard 55-1992, which indicates that Malaysians are acclimatized to higher environmental temperatures. However, the result is in line with the current version of ASHRAE Standard 55-2004 that includes an adaptive comfort standard that allows warmer indoor temperatures for warmer climate zones. The results of a ventilation study indicated air flow patterns in the occupied zones, which approximated to "perfect mixing" under both ventilation conditions. The measured air exchange rate also indicated that the provision of outside air for ventilation was adequate when the room was mechanically ventilated (air-conditioned). Results of over 50 survey responses to thermal comfort questions in the study room at UPM are given

An experimental study on double-glazed flat plate solar water heating system in Turkey

Domestic hot water preparation systems with flat plate solar collectors are widely used in Turkey. In this collector, the temperature difference between the required water temperature and the ambient air temperature increase causes a decrease in the efficiency of the collector. In this study, the use of double glass in order to increase the efficiency of the collector is studied experimentally. The location is in Isparta South West Turkey. Experimental study is conducted in May 2013 at the Suleyman Demirel University, Isparta. The system components are solar simulator, solar collector, tank, circulation pump, flowmeter, thermocouples, data acquisition device and solar sensor. Solar collector system's operating temperature is 50°C for winter also summer. The difference between the collector temperature and the ambient air temperature exceeds 25°C in many cases, were found to be more efficient double-glazed collectors. When the temperature difference is 40°C, using double glazing collector is 24% more efficient than using single glazing collector

Numerical simulation on the reflection characterisation and performance of a solar collector - a case study of UPM solar bowl

A numerical simulation of UPM Solar Bowl is presented in this paper. The numerical analysis considered a general model of solar bowl, which was divided into three modules:(a) reflection characterisation of the bowl, (b) solar flux density along the receiver, and (c) radiation contour mapping of the receiver. The governing equations are resolved in a segregated manner using Matlab programming environment. The influence of the tropical clear sky irradiance on the collector was numerically studied, whereas the collector performance in time domain was also quantified. Single reflection is a major element in thermal concentration. It was observed that solar flux density of collector substantially deteriorated during off solar noon hour, in which during 08:00 and 16:00 under clear sky of tropics, the percentage reduction of flux density is over 82% at all points of the receiver. The simulated radiation contour mapping of the receiver supports the finding. Other results of the UPM Solar Bowl simulation model are also shown and discussed

Development of 3D CFD simulation method in nuclear reactor safety analysis

One of the most prevailing issues in the operation of Nuclear Reactor is the safety of the system. Worldwide publicity on a few nuclear accidents as well as the notorious Hiroshima and Nagasaki bombing have always brought about public fear on anything related to nuclear. Most findings on the nuclear reactor accidents are closely related to the reactor cooling system. Thus, the understanding of the behaviour of reactor cooling system is very important to ensure the development and improvement on safety can be continuously done. Throughout the development of nuclear reactor technology, investigation and analysis on reactor safety have gone through several phases. In the early days, analytical and experimental methods were employed. For the last three decades 1D system level codes were widely used. The continuous development of nuclear reactor technology has brought about more complex system and processes of nuclear reactor operation. More detailed dimensional simulation codes are needed to assess these new reactors. This paper discusses the development of 3D CFD usage in nuclear reactor safety analysis worldwide. A brief review on the usage of CFD at Malaysia’s Reactor TRIGA PUSPATI is also presented

Field performance analysis of shoes used in the takraw games in Malaysia

Using proper footwear is crucial to avoid pain, deformations and injuries on foot. For athletes, a pair of good shoes is vital for comfort and may add to performance improvement. The main objective of this study is to study the performance of some commonly used shoes in the takraw games by using experimental tests and thermal measurements. The momentum and kinetic energies that were generated by the takraw shoes were also measured. The methods used in this study included free fall test, impact force analysis and surface thermal assessment. From the outcomes of the experiments, it was found that the prototype FA shoe was better in absorption of momentum and impact force than the other shoes and also with lower surface temperature after the trial game. These outcomes suggested that it was more suitable to be worn by the takraw players for better performance. All the information obtained from this study are particularly useful for improvement on the current design of takraw shoe

A technique to capture multi-disciplinary tacit knowledge during the conceptual design phase of a building project

The construction industry is suffering from incomplete knowledge flow that results in time and cost over-runs. Many researchers believe that a large part of this problem is related to the design phase being a tacit knowledge-dominated area. Since tacitness of knowledge contributes to incomplete flow of knowledge, we posit that facilitating the conversion of tacit knowledge to explicit knowledge can improve the overall knowledge flow. Within this context, this paper analyses recognised knowledge-capturing techniques and compares them in view of the operating characteristics of the conceptual design phase. This paper proposes a new tacit knowledge-capturing technique for this phase. The outcomes include a new knowledge-capturing technique, a method for validation of the proposed technique, and recommendations on how to deal with the challenges concomitant with the application and utilisation of the proposed technique in the building industry. By proposing a combinational tacit knowledge-capturing technique, this study attempts to mitigate the impact of the potential incomplete knowledge flow during the conceptual design phase in building projects

Fuel properties and rheological behavior of biodiesel from egusi (Colocynthis citrullus L.) seed kernel oil

In this study, egusi (Colocynthis citrullus L.) seed kernel oil has been evaluated as a feedstock for biodiesel production. The transesterification of the crude egusi seed kernel oil (CESKO) via methanol in the presence of sodium methoxide was performed and the resulting egusi oil methyl ester (EOME) was tested for its fatty ester composition, fuel properties and rheological behavior (at 25 °C, 40 °C and 55 °C). The fuel properties of EOME measured met both the ASTM D6751 and EN 14214 biodiesel standards, with the exception of lower oxidative stability. The fatty ester composition and fuel properties of EOME were found comparable to those of conventional biodiesels from soybean, sunflower and safflower oils. The viscosity behavior of EOME and its blends with diesel fuel (at 25 °C, 40 °C and 55 °C) was found to be pseudoplastic and Newtonian in nature and this agrees with those of other biodiesels reported in literature. From this study, the kinematic viscosity of EOME (3.91 mm2/s) was found to be slightly lower than that of most biodiesels (≥ 4.0 mm2/s) reported in literature