Study on Blast Pressure Resistance of Foamed Concrete Material

Great demand exist for more efficient design to protect personals and critical components against explosion or blast wave, generated both accidentally and deliberately, in various blast scenarios in both civilian and military activities. Concrete is a common material used in protective design of structures. Recently, the demands on producing the lighter concrete material have become interest in concrete research. Foamed concrete is a possible alternative of lightweight concrete for producing intermediate strength capabilities with excellent thermal insulation, freeze-thaw resistance, high-impact resistance and good shock absorption. This paper explores the role and development of Blast Pressure Resistant Materials (BPRM’s) on foamed concrete. The explosive tests were conducted to determine the blast mitigating properties. The results show that when the foamed concrete density is increases the blast energy absorption capability will be decreases due to reduce of cavity volume. This is suggested that cavity plays an important role to dissipate and absorb the shock energy of the blast

Determinants of snakebite mortality in Asia: A systematic review

Purpose: This systemic review summarizes the evidence exploring the determinants of mortality due to snakebite envenomation in Asia. Materials and methods: The database PubMed, Web of Science and Science Direct were searched to identify the relevant literatures concerning mortality due to snakebites mortality in Asia. All the articles chosen were critically appraised for its quality using a mixed-method assessment tool by two independent reviewers with discrepancies sorted by a third person. Results: A total of 7 studies were included in the final analysis which was 3 cross-sectional studies, 2 case reports, 1 observation prospective study and 1 randomized control trial study. Two studies were conducted in India and two studies in Sri Lanka while one study was conducted in Taiwan, Vietnam and Nepal respectively. The cases of snakebite victims were retrieved from the year of 1987 until 2017. In total, there were 762 cases of snakebite victims recorded, with 61 of those victims succumbed to death. From the final total of 7 studies, 4 of the studies showed snakebites mortality were related to delayed treatment access and 3 studies due to suboptimal care. Conclusion: Mortality and morbidity can be reduced if there is a quick access for victims to emergency medical care, rapid transfer time to hospital and receiving immediate optimal medical treatment from trained medical staff once in the hospital or dispensary. © 202

Fuel consumption evaluation of SI engine using start-stop technology

The engine start-stop technology is gaining acceptance as a key technology adopted by manufacturers to improve the fuel economy of passenger cars. This technology shuts the engine off when a vehicle is at a stop. The inherent issue with the implementation of the start-stop technology in hot climates is the requirement for the air-conditioning system to be in constant operation which reduces the duration of engine shut-off during vehicle stops, and consequently, nullifying the benefit of the system. The aim of this study is to evaluate the potential fuel consumption improvements on a spark ignition engine when using the start-stop technology in real conditions of the Malaysian tropical climate, with consideration towards cabin comfort temperature. The result provides useful insight and enables vehicle manufacturers to assess whether such technology is feasible for implementation in tropical climates. A 1.6 litre spark ignition engine was modelled along with an air-conditioning system model using a commercial one-dimensional engine simulation gas dynamic software. A vehicle driving profile of engine speed and engine torque obtained from real driving on Malaysian roads was captured and used as the boundary conditions for the simulation. Iterations of the start-stop strategy were simulated to further explore the possible impacts on fuel consumption. The result of this study showed that the duration of engine shut-off during vehicle stops becomes shorter due to the necessity of the air-conditioning system to operate in maintaining the cabin’s comfort temperature. With the shorter duration of engine shut-off, the fuel consumption improvement stemming from the start-stop technology is reduced from the average of 20.7 % to 11.0 %, therefore, addressing the concerns on the application of the start-stop technology in hot climate countries and the opportunity to further optimise fuel consumption

Benefits of spark-ignition engine fuel-saving technologies under transient part load operations

This paper presents a simulation-based study to evaluate three potential benefits of fuel-saving technologies implemented in spark-ignition (SI) engines for a passenger car over actual urban driving cycles. These technologies include cylinder deactivation (CDA), stop-start system, and engine downsizing (≈20% degree of downsizing). The aim of the work is to evaluate individual benefits of each system in terms of fuel consumption. GT-Power engine simulation tool is utilised to model engines which employ each of the mentioned technologies; each of the engines has identical full-load torque characteristics. Each engine model is instructed to run over a transient, part-load, torque driven operations based on actual road test measurements, and the cycle-averaged fuel consumption was evaluated. From the analysis, the contribution of each technology in terms of fuel economy can be assessed based on an actual part-load transient operation, which can be beneficial to developers to optimise the operation of SI engines. The results revealed stop-start system to be the most promising technology for the driving cycle at hand with 27.5% fuel consumption improvement over the baseline engine. CDA engine allows for 12.6% fuel economy improvement. On the other hand, the downsized turbocharged engine has caused increasing cycle fuel consumption by 7.5%. These findings are expected to be valid for typical urban driving cycles as far as they conform to the operating load residency points over the transient torque profile