Wind characteristics and outdoor thermal comfort assessment in east Malaysia

Rapid urbanisation and industrialisation have had an adverse and deep impact on the environment contributing to global warming and climate change. These thermal environmental problems can be even more challenging to people living in regions with warm and humid climatic conditions throughout the year, such as Malaysia. This paper analyses wind characteristics and outdoor thermal comfort index at the hottest temperatures based on data recorded hourly between 2012 and 2014 for two cities in East Malaysia, namely Kuching (Sarawak) and Kota Kinabalu (Sabah). Wind characteristics were analysed using only wind velocity and direction, while the level of outdoor thermal comfort was measured using Universal Thermal Climate Index (UTCI). The results showed that hourly average wind velocities for Kuching and Kota Kinabalu were 1.84 m/s and 2.15 m/s respectively while the highest average wind velocities was 10.1 m/s and 12.4 m/s respectively. No wind movement (i.e. 0 m/s) was recorded for both locations. The prevailing annual wind flow is generally from South-Southeast (150°) in Sarawak and from East-Southeast (110°) in Sabah. It was also found that both Kuching and Kota Kinabalu experienced strong and extreme heat stress conditions with UTCI levels of 44.8°C and 49.8°C respectively. Thus, it can be concluded that, East Malaysia faces strong and extreme heat stress conditions. This study is an original contribution on the subject of outdoor thermal environment in Malaysia, Further research to better understand outdoor thermal environmental problems is recommended

Resolution of inflammation: a new therapeutic frontier

Dysregulated inflammation is a central pathological process in diverse disease states. Traditionally, therapeutic approaches have sought to modulate the pro- or anti-inflammatory limbs of inflammation, with mixed success. However, insight into the pathways by which inflammation is resolved has highlighted novel opportunities to pharmacologically manipulate these processes — a strategy that might represent a complementary (and perhaps even superior) therapeutic approach. This Review discusses the state of the art in the biology of resolution of inflammation, highlighting the opportunities and challenges for translational research in this field

Costing structure improvement using activity based costing in palm oil plantation of Malaysia

Malaysia is one of the largest producers and exporters of palm oil in the world, accounting for 11% of the world's oils & fats production and 27% of the export trade of oils & fats. Oil palm tree will start bearing fruits after 30 months of field planting and will continue to be productive for the next 20 to 30 years. Thus, a proper costing method is very important in order to have a clear picture of its profit loss and gain for the next 20 to 30 years. The aim of this work is to apply the activity based costing (ABC) as a method of cost estimation for the palm oil plantation. The ABC has been applied to analyze the costing for every activity involved in the palm oil plantation. The actual cost information of each activity has been obtained through a process flowchart. Other than that, proper cost driver has been assigned in order to obtain the actual manufacturing cost of an oil palm plantation. The expected monthly manufacturing costs of xxx company has been calculated which is MYR 494303.04 and consequently the accurate profitability can be achieved. Accurate profitability is the most important factor for the management to identify the money that process in order to maintain rapid but sustainable growth. Therefore, ABC has assigned actual cost information and proper cost drivers for each of the activities being involved and it makes the company’s profitability more accurate

Prediction of the flow around a surface-mounted cube using two- equation turbulence models

The flow around surface-mounted cube under neutral atmospheric boundary layer was simulated using two-equation turbulence models. The accuracy of two-equation turbulence models to model the flow fields were compared against full y documented experimental data. To build low computational cost, mesh refinements were investiga ted through mesh independence study by means of standard wall functions for the near wall treatment. All the two-equations turbulence models are shown to be underpredict the separation length and overpredict the reattachment length near the cube wall. In particular, the standard k-ε turbulent scheme shows good agreement with experimental data of streamwise velocity flow along the symmetry plane behind the cube

Heat and mass transfer characteristics of carbon nanotube nanofluids: A review

The pursuit of superior working fluids for heat and mass transfer systems in the industry is on the rise, inspired by not only to maximize revenue but also to accommodate heat dissipation or chemical separation under extreme conditions. The addition of a small amount of nanoparticle, a product called nanofluid, has been initiated over the last decade. In particular, researchers have employed carbon nanotubes (CNTs) into conventional fluids as their preferred nanoparticles due to the merits of having a remarkable thermal conductivity compared to other nanoparticles. Here, we present a comprehensive and up to date review of this incredible fluid being applied in various heat transfer (convective and boiling) and mass transfer systems such as heat exchangers and separators. Other critical parameters associated with the practicality of the CNT nanofluids such as pumping power and efficiency are also discussed. We surveyed a remarkable range of results of some of the heat and mass transfer studies that strongly depend on the inherent CNT nanofluid characteristics and operating conditions such as CNT treatment, size, concentration, Reynolds number, and so on. A major conclusion that can be drawn from this review is the significantly higher heat transfer coefficient at lower pressure drop or pumping power of the CNT nanofluid compared to other nanofluids, which implied better thermal performance of the heat transfer system. Besides that, the concentration of CNT is the influential factor to achieve optimum boiling heat transfer while the mass transfer performance of the CNT nanofluid is moderately good against other nanofluids. Additionally, CNT treatment using covalent functionalization is crucial for the overall stability and performance of the CNT nanofluid. However, several issues that inhibit their widespread use such as possible corrosion-erosion in systems, lack of risk assessments, and high cost of CNT nanofluid must be thoroughly addressed in future studies

A study of cavitation effect in a journal bearing using CFD: a case study of engine oil, palm oil and water

Cavitation is a common phenomenon in journal bearing, which plays a crucial role in lubrication efficiency. However, the degree to which the cavitation phenomenon affects the lubrication performance for a different type of lubricant is still unclear. Therefore, in this paper, a comparison between the case of ‘cavitation’ and ‘without cavitation’ phenomena for journal bearing is presented. This study focused on three different types of lubricants which can be categorized into renewable and non-renewable resources, which are water, palm oil, and engine oil (SAE20W40). The uniqueness of our study is the inclusion of renewable sources, which is palm oil. Numerical analysis was chosen as an approach tool via ANSYS FLUENT. The cavitation process is investigated with a change in the pressure distribution of the oil film in the journal bearing. In the situation of non-cavitation model applied, the cavitation effect is neglected which has yielded a different value of pressure maximum and a minimum of the fluid film as compared if the cavitation concept is introduced. This study demonstrates the importance of the cavitation approach incorporation in the numerical prediction of lubrication in a hydrodynamic journal bearing

Numerical investigation of drag force on micro-sized magnetic beads in microchannel with chamber design

Biological cells or bioparticles separation is a primary step in most biological studies. One of the microfluidic bioparticles separation methods is the magnetic-based method. Integrated microfluidic magnetic bioparticle separation device is made up of a microfluidics channel and a magnetic system. From past studies, the design of the microfluidic channel is least discussed in comparison with the magnetic system. To fill this gap, this study has focused on numerical simulation of a microfluidic channel with chamber design and the drag forces experienced by the magnetic beads. Simulation of the microfluidics channel was done with ANSYS Fluent software. The width ratios of trapping chamber and main channel ranged from 1 to 20, the flow rates ranged from 1 μL/min to 100 μL/min, and the bead sizes ranged from 5 μm to 25 μm were used in the numerical investigation. It was discovered that as the width ratio between the trapping chamber and main channel increases, the maximum velocity decreases, causing the Reynold's number to decrease. The pressure drop become greater at higher flow rate. Higher width ratio caused the drag force to reduce at a constant microbead size. At a constant width ratio between the trapping chamber and main channel, larger microbead sizes caused larger drag force. The microfluidic system with width ratio of 20 and flow rate of 1 μL/min produced the lowest drag force, 3.64 x 10 4 pN. Since particle trapping would occur when the magnetic force is larger than the drag force, therefore a high gradient magnetic system which offered high magnetic force was proposed to be integrated with the microfluidics system

Recent progress on the application of nanofluids in minimum quantity lubrication machining: A review

This paper reviews recent progress and applications of nanofluids in machining processes. In addition to reviewing the various conventional and advanced cooling techniques during machining, the paper also discusses the preparation methods, factors for enhancing thermal conductivity and properties of nanofluids. In line with fast development of nanofluid in machining process, the purpose of this paper is to review recent progress on the application of nanoparticles in lubricants especially for MQL technique. The conclusions and important summaries were also presented according to the data collected

Latest development on computational approaches for nanofluid flow modeling: Navier-Stokes based multiphase models

Nanofluids have gained significant attention in recent years due their great potential for heat transfer enhancement. The heat transfer of nanofluids can be numerically studied using a single-phase or two-phase approaches. The first assumes that the fluid phase and nanoparticles are in thermal equilibrium and move with the same velocity, while the second requires more computational effort but provides the possibility of understanding the behavior of both fluid phase and solid particles in the heat transfer mechanism. This paper reviews various computational approaches to predict fluid flow and heat transfer characteristics of nanofluids. The characteristics of single-phase and two-phase (volume of fluid, mixture, Eulerian-Lagrangian and Eulerian-Eulerian) approaches have been analyzed and discussed systematically. Latest development and recent researches related to the computational nanofluids are also given