Temperature and heat flux measurement techniques for aeroengine fire test: a review

This review is made of studies whereby some types of fire test measuring instrument were compared based on their mode of operation, sensing ability, temperature resistance and their calibration mode used for aero-engine applications. The study discusses issues affecting temperature and heat flux measurement, methods of measurement, calibration and uncertainties that occur in the fire test. It is found that the temperature and heat flux measurements of the flame from the standard burner need to be corrected and taken into account for radiation heat loss. Methods for temperature and heat flux measurements, as well as uncertainties analysis, were also discussed

Granite Exploration by using Electrical Resistivity Imaging (ERI): A Case Study in Johor

Electrical Resistivity Imaging (ERI) is a tool used in near surface geophysical surveys by flowing an electric current through electrodes that were injected into the ground. The usage of electrical resistivity imaging (ERI) method dominated by geophysicist has increased tremendously in geotechnical engineering application owing to the efficiency and effectiveness of the method in term of time, cost and also data coverage. The survey performed with respect to the particular reference to ERI in determining the granite rock underneath the ground. There were seven (7) lines of ERI performed at the study area by using ABEM Terrameter LS 2 set of equipment based on Schlumberger protocol. Six (6) boreholes were also drilled to obtain engineering properties of rock at the study area. In order to develop the relationship between resistivity and engineering properties, a comparison between borehole field test result and the resistivity value were made. Results from the ERT indicated the presence of zones with high resistivity values identified as overburden soil, fractured granite and solid granite. The findings of this study also showed that the electrical resistivity imaging coupled with borehole drillings were applicable tools for the determination of the granite rock underneath the ground via subsurface profiles and such as depth of overburden soil and engineering properties of soil

Thermal insulation properties of organic and inorganic material in clay brick - a review

Pore forming agent is widely used in clay brick making process whether originally organics or inorganics materials which can improve thermal insulation facing global warming issue. Many researchers trigged to discover the thermal insulation materials since the past decade due to responsibility to develop a comfort living demand for heating or cooling. This paper review on different types of thermal inorganic and organic insulation materials added into a clay brick to improve the thermal insulation properties. The scope of these reviews lies to the materials of; paper residue, rice husk, rice husk ash, olive stone flour, wheat straw, perlite, cigarette butt, vermiculite, waste marble powder and waste glass sludge. The discussions are made based on the properties of organic and inorganic materials used in improving the thermal insulation in clay brick. Hence, a throughout review of the composition and properties of brick and various factor related to manufacturing process is highly required for better standardization of clay bricks. A better understanding of different wastes incorporating clay brick utilize of various mining and industrial as well as achieving the goal of sustainable development

Comparative genetic stock structure in three species of commercially exploited Indo-Malay Carangidae (Teleosteii, Perciformes)

We examine genetic structuring in three commercially important species of the teleost family Carangidae from Malaysian waters: yellowtail scad Atule mate, bigeye scad Selar crumenophthalmus and yellowstripe scad Selaroides leptolepis, from the Indo‐Malay Archipelago. In view of their distribution across contrasting habitats, we tested the hypothesis that pelagic species display less genetic divergence compared with demersal species, due to their potential to undertake long‐distance migrations in oceanic waters. To evaluate population genetic structure, we sequenced two mitochondrial (mt)DNA [650bp of cytochrome oxidase I (coI), 450bp of control region (CR)] and one nuclear gene (910bp of rag1) in each species. One hundred and eighty samples from four geographical regions within the Indo‐Malay Archipelago including a population of yellowtail from Kuwait were examined. Findings revealed that the extent of genetic structuring among populations in the semi‐pelagic and pelagic, yellowtail and bigeye were lower than demersal yellowstripe, consistent with the hypothesis that pelagic species display less genetic divergence compared with demersal species. The yellowtail phylogeny identified three distinct clades with bootstrap values of 86–99% in mtDNA and 63–67% in rag1. However, in bigeye, three clades were also observed from mtDNA data while only one clade was identified in rag1 dataset. In yellowstripe, the mtDNA tree was split into three closely related clades and two clades in rag1 tree with bootstraps value of 73–99% and 56% respectively. However, no geographic structure appears in both mtDNA and rag1 datasets. Hierarchical molecular variance analysis (AMOVA), pair wise FST comparisons and the nearest‐neighbour statistic (Snn) showed significant genetic differences among Kuwait and Indo‐Malay yellowtail. Within the Indo‐Malay Archipelago itself, two distinct mitochondrial lineages were detected in yellowtail suggesting potential cryptic species. Findings suggests varying degrees of genetic structuring, key information relevant to management of exploited stocks, though more rapidly evolving genetic markers should be used in future to better delimit the nature and dynamics of putative stock boundaries

An analytical study on the performance of the organic rankine cycle for turbofan engine exhaust heat recovery

Due to energy shortage and global warming, issues of energy saving have become more important. To increase the energy efficiency and reduce the fuel consumption, waste heat recovery is a significant method for energy saving. The organic Rankine cycle (ORC) has great potential to recover the waste heat from the core jet exhaust of a turbofan engine and use it to produce power. Preliminary study of the design concept and thermodynamic performance of this ORC system would assist researchers to predict the benefits of using the ORC system to extract the exhaust heat engine. In addition, a mathematical model of the heat transfer of this ORC system is studied and developed. The results show that with the increment of exhaust heat temperature, the mass flow rate of the working fluid, net power output and the system thermal efficiency will also increase. Consequently, total consumption of jet fuel could be significantly saved as well

Thermal Analysis of Al2O3–water Ethylene Glycol Mixture Nanofluid for Single PEM Fuel Cell Cooling Plate: An Experimental Study

Thermal enhancement through application of nanofluid coolant in a single cooling plate of Polymer Electrolyte Membrane (PEM) fuel cell was experimentally investigated and reported in this paper. The study focuses on 0.1 and 0.5% volume concentrations of Al2O3 dispersed in 60:40 and 50:50 of water (W)–ethylene glycol (EG) mixtures as coolant in a carbon graphite PEM fuel cell cooling plate. The study was conducted in a cooling plate with 22 parallel mini channels and large fluid distributors under constant heat load of 100 W. The effect of different flow rates to heat transfer enhancement and fluid flow in Reynolds number range of 20–120 was observed. Positive heat transfer enhancement was obtained where the heat transfer was improved up to 23% and 21% for 0.5% concentration Al2O3 nanofluid in 60:40 and 50:50 (W:EG) consecutively as compared to the base fluid. However, higher pressure drop was also experienced as much as 17% and 20% for 0.5% concentration Al2O3 in 60:40 and 50:50 (W:EG) consecutively as compared to the base fluid. Combination of both heat transfer enhancements and pressure drop demerits was then analyzed using advantage ratio. The results implied that 0.1% Al2O3 in 60:40 (W:EG) is the most advantageous nanofluid candidate followed by 0.1% Al2O3 in 50:50 (W:EG). Both nanofluids have advantage ratio values of greater than 1

Automobile compression composite elliptic spring

An automotive suspension system is designed to provide both safety and comfort for the occupants. When a vehicle encounters a road surface irregularity, the tire deforms and the suspension displaces. Some of the energy caused by the disturbance is dissipated in the tire, while in the old design, some energy is dissipated in the shock absorber and the remainder of the energy is stored in the coil spring. In this paper, Finite element models were developed to optimize the material and geometry of the composite elliptical spring based on the spring rate, log life and shear stress. The influence of ellipticity ratio on performance of woven roving wrapped composite elliptical springs has been investigated both experimentally and numerically, this study demonstrated that composites elliptical spring can be used for light and heavy trucks and meet the requirements, together with substantial weight saving. The results showed that the ellipticity ratio significantly influenced the design parameters. Composite elliptic spring with ellipticity ratios of a/b 2 displayed the optimum spring model

Methods for improving the workability of natural ester insulating oils in power transformer applications: a review

Even though natural insulating oils (NEI) oils are environmentally friendly, these oils have not gained widespread use in high-voltage oil-immersed power transformers because of their unfavorable properties such as low pour point, low oxidation stability, low resistance to lightning impulse, and high kinematic viscosity. Hence, much effort has been made to overcome the disadvantages of NEI oils, including the addition of additives, modification of the chemical structure of oils and altering the transformer design to ensure compatibility with the oils. This review article is focused on the methods used to improve the workability of NEI oils in power transformers, namely, (1) depression of the pour point, (2) chemical modifications, (3) changes in the transformer design, (4) addition of nanoparticles, (5) addition of lightning resistance additives, and (6) addition of antioxidants. The benefits and challenges of each method are also discussed. It is believed that this review article offers new insight to scientists and researchers in this field