bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Study on Influence of Surfactant Dosage on Micro Explosion Occurrence in Water in Diesel Emulsion
Authors: Yahaya Khan Mohammed , Abdul Karim Z.A. , Aziz A. Rashid A. , Tan Isa Mohd
Published: January 2016

An experimental investigation has been carried out to study the effect of surfactant dosage on micro explosion phenomenon. Three water in diesel emulsion with 20% water by volume was prepared using mechanical stirring at 17000rpm for 100s.The emulsions were stabilised by a were stabilized by a single surfactant with three different doses. Water in diesel emulsion droplet was suspended on a thermocouple and the evolution of micro explosion was recorded with a high speed camera synchronized with temperature data logger. Secondary atomization of emulsion droplet was observed under Leiden frost regime using a hot plate as the heat source. The results show that the occurrences of micro explosion are affected by the volume of added surfactant by influencing the exploding temperature and waiting time. Physical properties like density, viscosity and surface tension were also found to be influenced by the amount of surfactant used.
Thermal Conductivity of Carbon Nanotube Based Nanofluids as Heat Transfer Fluids
Authors: Leong Kin Yuen , Che Ibrahim Ibnorita , Amer Noor Hafizah , Risby M.S.
Published: January 2016

Conventional heat transfer fluids such as water and ethylene glycol exhibit low thermal conductivity. These fluids have certain influences on the efficiency of the thermal system. Efficiency of the thermal system is dependent on the thermal conductivity of the heat transfer fluid. New generation of heat transfer fluid such as nanofluid has potential to address this major problem. Therefore in this study, the thermal conductivity characteristic and stability of multiwalled carbon nanotube based water nanofluids was investigated. Two types of surfactants namely gum arabic and sodium dodecylbenzene sulphate (SDBS) were used to stabilize the nanofluid. Findings implied that thermal conductivity of water increases with the loading of multiwalled carbon nanotube nanoparticles. As for the stability, study shows that nanofluids added with SDBS are more stable compared to that of samples with gum Arabic.
Progress and Challenges in the Development of Detonation Engines for Propulsion and Power Production
Authors: Lu Frank K.
Published: January 2016

The scientific study of detonation stretches over a century and the potential to harness detonations for propulsion and power was recognized for almost as long. It is only in the past two decades that detonation applications have received intense attention. Attractions for utilizing detonations include the higher theoretical thermodynamic efficiency compared to deflagration-based systems, high power-to-weight or volume ratio and lack of moving parts. Despite these attractive features, a number of fundamental physics and engineering challenges must be overcome before such systems can be practical. Some of these include the ability to achieve consistent and reliable detonations in a practical arrangement, understanding of the unsteadiness, and integration with ancillary systems. Illustrations will be provided on how some of these issues were understood and overcome. Potential challenges are also highlighted.
Optimal Frictional Pressure Drop and Vapor Quality Relationship of Ammonia and R22 in Two-Phase Flow
Authors: Mohd Ghazali Normah , Jong-Taek Oh , Ahmad Robiah , Zolpakar Nor Atikah
Published: January 2016

Research in two-phase flow in heat exchanging devices plays an important part in today’s applications in miniaturization of engineering systems. The phase change process factors in the flow conditions and heat transfer in evaporators and condensers. Numerous studies in the past have looked at the predicted and measured frictional pressure drop of coolants as the vapor quality increases. This paper reports a preliminary attempt at modeling of the relationship between the frictional pressure drop and vapor quality in an ammonia-cooled and R22-cooled mini-channel of 1.5 mm diameter under optimized conditions using multi-objective genetic algorithm. R22 is a being phased-out due to its ozone-depleting characteristic and ammonia is being considered as its potential replacement. The properties of ammonia and R22 used have been obtained experimentally at the saturation temperature of 5°C and 10°C respectively. Modeling of the minimized pressure drop per unit tube length together with the Lockhart-Martinelli parameter was completed under optimized flow rate and vapor quality.The outcomes obtained are similar to those that have been reported experimentally with other coolants, increasing pressure drop with increasing vapor quality.
Investigation of Physical and Mechanical Properties of 3-D Turbulent Flow in Orifice Pipe
Authors: Alabas Siba Mohamed Abed , Wan Mahmood Wan Mohd Faizal , Nuawi Mohd Zaki , Rasani Rasidi , Nassir Mohamed
Published: January 2016

The turbulent flow in orifice plate was investigated and solved numerically using 3-D Navier-Stockes (N-S) equations by employing commercial CFD code ANSYS. The N-S equations were solved for unsteady flow of an orifice plate at different values of Reynolds number, Re=ρVDμ, and different aspect ratios, β=dorificedpipe. Physical parameters such as velocity, differential pressure, and vorticity and mechanical properties such as stress, strain, and total deformation were examined for Reynolds numbers of 10000, 20000, and 30000 and at aspect ratios β of 0.2, 0.4, and 0.6. It was found that as Reynolds number increases, the velocity increases while the differential pressure shows very steep jump across the orifice. As aspect ratio increases, the maximum pressure declines. The vorticity patterns show that images of very condensed lines. At certain aspect ratio, the differential pressure increases as Reynolds number increases.
Validation of a CFD Non-Newtonian Eulerian-Eulerian Model for Predicting Wellbore Filter Cake Formation
Authors: Shehata Ali I. , Shokry Mohamed , Saqr Khalid M. , Shehadeh Mohamed
Published: January 2016

During oil wellbore drilling processes, filter cake is formed on the sidewalls of the well hole due to filtration of drilling fluid particles. The filter cake is crucial to the drilling process, since it helps to maintain the wellbore hole, protects the drilling bit from jamming and facilitates the subsequent phases of the well development. The most important parameter for filter cake formation is its thickness and its variation due to drilling conditions. In this paper, the drilling fluid particles filtration process was simulated at conditions mimicking deep wellbore drilling. The drilling fluid was simulated as a non-Newtonian two-phase fluid of liquid and particles, utilizing an Eulerian-Eulerian approach. The model successfully predicted a filter cake thickness which agrees well with measurements and previous CFD work.
Performance Characteristic Study on Air to Water Intercooler
Authors: Engkuah Stannely , Nasution Henry , Abdul Aziz Azhar
Published: January 2016

The automotive vehicle with turbocharger engine will produce the high temperature charged air compared to the naturally aspirated engine. By increasing the pressure of the air, the temperature of the air will be increased while the air density will be decreased. The charged air needs to be cooled down to get the higher density of the charge air before flowing into the intake manifold. The charge air becomes denser when the temperature of the air is reduced and the denser air gives more advantages for the engine run efficiently. The intercooling system is one of the important devices in cooling process of the turbocharger engine. The function of the intercooler system is for cooling the temperature of the turbocharger outlet before the intake manifold. For this research, the water is used as the medium for cooling the temperature of the charge air before the intake manifold instead using of direct air that is the basic medium of intercooling system. The liquid cooled intercooler system type is constructed which wants to make it practically in daily life, such as for increasing the performance of the car and also for saving the fuel consumption of a vehicle.
Investigation of Performance and Fuel Economy for Cylinder Deactivation Engine at Part Load Operation
Authors: Zainal Abidin S.F. , Muhamad Said Mohd Farid , Aziz Azhar Abdul , Abas Mohd Azman , Arishad N.I.
Published: January 2016

In automotive engine applications, the spark ignition (SI) engines can operate at various engine speed and load conditions. However, most of the time was spend at part load operations, where they operate below their rated output especially during cruising or idling. The needs of improvement in term of engine efficiency at part load operation become more popular among the engine manufacturers. One of the main reasons for efficiency dropped at part load conditions is the flow restrictions at the throttle valve opening area due to nearly-close position to control amount of inducted air into the cylinder, which leads to increasing in pumping losses. Hence, there are a lot of studies and investigations have been carried out to tackle these problems without sacrificing the original performance. This paper will investigate further the engine efficiency, performance as well as fuel economy by using one-dimensional (1-D) simulation tool. A baseline simulation model of a 1.6 liters four cylinders, port fuel injection engine has been developed based on the actual engine geometries. This baseline model applied predictive combustion to predict the amount of cylinder pressure based on actual ignition and injection timing on bench. The simulated results show a very good agreement with the measured data. Additionally, this study also proved that the deactivation half of the cylinders can significantly reduce the pumping losses of fired cylinder while eliminated the pumping work of unfired cylinders.
Numerical Investigation on Hydrogen Permeation with Flat Sheet Pd/Ag Membrane for Various Geometries
Authors: Faizal Hasan Mohd , Yokomori Takeshi , Ueda Toshihisa
Published: January 2016

The variation in hydrogen concentration distribution on Pd/Ag membrane surface for permeation with H2/N2 mixture was investigated numerically, by varying the diameter of the mixture inlet. A 77wt.%Pd/23wt.%Ag purification membrane with thickness of 25μm and effective surface area of 3.14x10-4m2 was considered. The membrane temperature, total upstream pressure, and inlet H2 mole fraction were set to 623K, 0.25MPa and 0.75, respectively. Meanwhile, the downstream pressure was set at atmospheric. Mean mole flux (feed flow rate/effective membrane surface area) was varied between 0.19-0.95 mol.s-1.m-2. The hydrogen concentration distribution was investigated for various ratios of inlet radius to membrane radius (0.22:1, 0.50:1 and 0.75:1). It is found that hydrogen permeation flux obtained from various hydrogen concentration distributions are almost same, and quantitatively fit with analytical result based on the Sieverts’ equation with the effect of H2 permeation.
Investigation of Intake Valve Strategy on the Cylinder Deactivation Engine
Authors: Muhamad Said Mohd Farid , Latiff Zulkarnain Abdul , Zainal Abidin Shaiful Fadzil , Zahari Izzarief
Published: January 2016

There are many technologies that being developed to increase the efficiency of internal combustion engines as well as reducing their fuel consumption. In this paper, the main research area is focus on cylinder deactivation (CDA) technology. CDA mostly being applied on multi cylinders engines. CDA has the advantage in improving fuel consumption by reducing pumping losses at part load engine conditions. Here, the application of CDA on 1.6L four cylinders gasoline engine was studied. One-dimensional (1D) engine modeling is performed to investigate the effect of intake valve strategy on engine performance with CDA. 1D engine model is constructed according to the 1.6L actual engine geometries. The model is simulated at various engine speeds at full load conditions. The simulated results show that the constructed model is well correlated to measured data. This correlated model used to investigate the CDA application at part load conditions. Also, the effects on the in-cylinder combustion as well as pumping losses are presented. The study shows that the effect of intake valve strategy is very significant on engine performance. Pumping losses is found to be reduced, thus improving fuel consumption and engine efficiency.
Alternative Lubricants: Study on Plant-Based Lubricants in Metal Forming Process
Authors: Nurul M.A. , Syahrullail Samion
Published: January 2016

In this paper, the effect of metal-to-metal contact from the application of plant-based lubricants, RBD palm olein and jatropa were investigated by cold work forward plane strain extrusion experiments. A pair of taper die and a symmetrical workpiece (billet) was placed inside extrusion rig which acted as main experimental apparatus. The billet material was annealed pure aluminum A1100 with radius 5 mm in deformation area. The experimental result shows that the lower viscosity index, will lead to lower friction effect to the deformed area, as well as product area.
Analysis of Porous Layered Journal Bearing Lubricated with Ferrofluid
Authors: Rao T.V.V.L.N. , Rani A.M.A. , Nagarajan T. , Hashim F.M.
Published: January 2016

This paper presents an analysis of porous layered long journal bearing lubricated with ferrofluid using displaced infinitely long wire magnetic field model. The ferrofluid flow in the porous region is analyzed using modified Brinkman model. Nondimensional pressure and shear stress expressions are derived using Reynolds boundary conditions. Nondimensional load capacity and coefficient of friction are evaluated under the influence of permeability of porous media, porous layer thickness, lubricant layer thickness, magnetic field intensity and distance ratio parameter. A porous layered journal bearing lubricated with ferrofluid increases the load carrying capacity and reduces the coefficient of friction.
Evaluation of Palm Olein as Shaft Lubricant
Authors: Sapawe Norzahir , Syahrullail Samion , Muhammad Farizudin
Published: January 2016

The demand and usage of vegetable oil utilization in lubricants for many applications increased prompting by continued growing environmental concerns. Today, vegetable oil attracts attention as biodegradable alternates for synthetic esters because they are cheaper and can be obtained from sources that are renewable. The main objectives of this experiment were to measure the friction force at various speeds and to observe the surface roughness before and after experiment. In this experiment, RBD palm olein as represented vegetable oil has been tested by compare the result with fully synthetic oil and mineral-based oil by using modified pin-on-disc machine. Pure RBD palm olein, recorded only 7.4% of increment of maximum friction force compared to results for mineral-based oil. Observation based on surface roughness show that RBD palm olein works as effective as fully synthetic and mineral-based oil since only 14.6% increment of overall surface roughness for the whole shaft. Therefore, the performance of vegetable oil which in this experiment is RBD palm olein, can be improve by adding additive so increase it properties such as can withstand at high load, high flash point parameter, small wear scar diameter, less oxidation rate, and coefficient of friction.
Effects of Different Load with Vary Lubricant on the Friction Coefficient and Wear Rate Using Pin on Disk Tribometer
Authors: Syahrullail Samion , Nuraliza Norawzi
Published: January 2016

A study has been created on the wear rate and friction constant for various material under the impact of load and material where the equipment pin on disk has been used to investigate the specification on the wear and constant of friction (COF) theory. The issues occur because of the metal-to-metal contact once interaction between two surfaces creates friction, wear and heat. It’ll cause every element life shortened, economically wasted, surface damage and cracks. This paper evaluates via pin on disc tribometer using SKD II and aluminum alloy, A 5083 as work pieces material. The test was tested using different type of lubricant (palm olein and mineral based oil) with different load. The result shows palm olein is more than mineral-based oil for constant friction as sliding speed increased and wear scar diameter lubricated with palm olein lower at low and high speed compared to the oil. As a conclusion, palm olein has better performance properties in terms of friction reduction (coefficient of friction) and wear resistance (anti-wear properties) at low and high speed. Pin that lubricated with palm olein showed small wear scar diameter compared to the mineral based oil. Therefore, palm olein has risk to use as a lubricant of mating components.
Low Energy Nuclear Reaction (LENR) – Sustainable and Green Energy: A Review
Authors: Akhter Md Zishan , Hassan M.Ashique
Published: January 2016

In this paper a review on recent development in Low Energy Nuclear Reaction (LENR) is presented along with scope and challenges. As the name suggests Low Energy Nuclear Reaction (LENR) is a phenomenon of nuclear reaction occurring in metal hydrides at ambient temperature. The products are generally Helium & significant amount of useful heat energy. During the process Transmutation of metal (host) occurs; occasionally producing some charged particles and neutrons. The LENR are successfully carried out with various elements namely; nickel, gold, palladium, platinum, titanium, certain superconducting ceramics, etc. LENR poses itself as a source of pollution free and inexhaustible energy source. It produces tremendous amount of heat energy during the reaction which surpasses all the available energy sources by a factor of hundredths to millions. Besides this it is also useful in transmutation of nuclear wastes. To initiate LENR there are various views floating around in scientific community. The purpose is to bring together two nuclei at low energy to fuse together as a single nucleus. A large amount of force is required which is generally obtained through plasma arc or accelerated high energy ions. But in case of LENR all the nuclear reaction occur at low energy thus saving excessive amount of energy required for activation. One of the most studied LENR involves palladium. The palladium is used at a loading between 0.9 and 0.94 to produce optimum results. It is a source of Energy which is more eco-friendly and productive than all the available energy sources known to us. Statistically 1% of the total Ni production can power the World that too at one-fourth the cost of burning fossils. Models are being developed with Carbon replacing Ni, thus it will convert carbon to nitrogen. LENR is also being developed for using nuclear wastes as fuel, transmuting them into non-radioactive elements. This will tag LENR as much greener and cleaner source. LENR is being also developed to be used as an alternative and richer energy source to radioactive fuels (like Pu-238), currently being used to power space probes. Thus it helps reduce the generation of hazardous nuclear wastes.
An Improved Cost Apportionment for Desalination Combined with Power Plant: An Exergetic Analyses
Authors: Shahzad Muhammad Wakil , Ng Kim Choon , Thu Kyaw
Published: January 2016

In this paper an improved method for fuel cost apportionment of a combined power cum a desalination plant is presented. The conventional analysis for cogeneration systems has been, hitherto, the energetic (enthalpy) method which is useful for efficiency evaluation purposes, but it may not be fully accurate for capturing the “quality of fuel energy” consumed by processes in producing two or more useful effects, e.g., electricity and water. An exergy destruction procedure is proposed for the cost apportionment of fuel energy consumed where the available work potential of expanding stream can be fully accounted for cost distribution of the designed processes. For example, the turbines, that is used for power generation, exploits mainly the sensible-energy changes of high enthalpy steam undergoing expansion at high pressures and temperatures, whilst the thermally-activated desalination processes, such as the multi-effect distillation (MED), needed only the high latent-heat of bled-steam but at low pressures that has negligible work potential if the steam were to be used in the turbines. From this analysis, the incurred exergy destruction by the desalination processes is only 2%-7% of the total destruction available to the plant with bled-steam up to 50% of the total flow. We examined the ratio of exergy destruction consumed by the water to power production and, such a ratio is used as a basis for the fuel-cost determination in the cogeneration plant. It captures not only the realistic exergetic value of bled-steam of MED desalination, but it exposes the major shortcomings of the conventional enthalpy changes where a disproportion share of the input fuel cost, up to 32% of the total fuel input, may have been erroneously apportioned and giving an unfair valuation of the operational water cost.
Experimental Investigation of Multijunction Solar Cell Using Two Axis Solar Tracker
Authors: Muhammad Burhan , Seung Jin Oh , Ng Kim Choon , Chun Wongee
Published: January 2016

Solar cell is the most cost effective and simple device to harvest solar energy as compared to other systems. Many types of single junction solar cell are available in market but their main problem is low efficiency. This paper focuses on the performance investigation of high efficiency multijunction solar cell using two axis solar tracker. High solar concentration is needed for multijunction solar cell with accurate solar tracking to get maximum energy output. Solar tracker is based upon the astronomical algorithm of solar tracking. Tracking System consists of GPS module, AVR microcontroller, stepper motors with drive modules and some other accessories. The tracking system takes geographical location data from GPS to calculate sun position for tracking.
Analysis of Center Pivot Irrigation System by Experimental Method
Authors: Musa Mohamad Nor , Taha Muhammad Ariff
Published: January 2016

The objective of this project is to design a center pivot irrigation system and determine the efficiency of the system by using experimental method by build a model of the system. For that, a literature study is carried out to understand the theories of center pivot irrigation system. Center pivot irrigation system is the system that can rotate 360 degree around the center pivot. Before model build, the theoretical calculation need to be done to calculate the specification of the model. The model of the experiment purpose build not included the rotation part because the rotation part not gives an effect to the water flow. The experiment procedure follows the standard of North Carolina State University that conducts this type of experiment. From the experiment, the uniformly efficiency of the irrigation system can be defined. Scaled model use in this experiment to determine the uniformly efficiency by using specification from the theoretical calculation. From the previous experiment the uniformly efficiency of the irrigation system is 50% - 60% and the uniformly efficiency of center pivot irrigation system is about 75% - 90%.
Study of Oxidation Behavior of Thermal Spray Coating on Superalloys at 900 °C
Authors: Kamal Subhash , Sharma Korada Viswanatha
Published: January 2016

An addition of cerium oxide to NiCrAiY coatings could boost the high temperature properties of the coatings in the actual service condition due to the purification of its microstructures. High temperature oxidation studies of D-Gun sprayed MCrAlY coatings with minor addition of CeO2 is inadequate in the literature. Therefore, the present work was focused to study the effect of cerium oxide on the high temperature oxidation behavior coatings on superalloys. Cyclic oxidation tests were carried out for 100 cycles at 900 °C to study the oxidation kinetics of un-coated and bare superalloys. The corroded products obtained during cyclic oxidation of coatings were subjected to XRD, FE-SEM/EDAX and X-ray mapping analysis to reveal the high temperature oxidation mechanisms.
Experimental Investigation on Contact Angle of Sintered Copper Powder Wick
Authors: Putra Nandy , Setyawan Iwan , Raditya Dimas
Published: January 2016

Heat pipes are widely used in electronic cooling and other applications that require efficient transport or spreading of heat from local sources of high heat flux. One factor that most affect the performance of this device is the wetting properties of the wick material, whereby a hydrophilic wick material is required to transport the liquid from the evaporator to the condenser. The performance of heat pipe will decrease when the wick surface becomes hydrophobic as indicated by changes in its contact angle (CA). This study aims to determine the effect of ambient air exposure on the wettability of wick material. Wettability for a surface by a certain liquid can be shown by measuring the contact angle of liquid droplets on the surface. In this experiment, the contact angle was captured using a high speed video camera followed by image processing and then measured using Image J software. The surface of the sample/wick is a sintered copper powder which in this study through a process of forming or compaction by various parameters such as powder particle size, compacting pressure and sintering temperature. From the results of this study was found that the longer wicks were exposed in the ambient air, the contact angle of the liquid on the wick surface will be getting increased. After 7 days were contaminated on the ambient air, then all samples have been turned into hydrophobic, CA>90°.
Dynamic Modeling of Solar Air Collector with Thermal Storage Material
Authors: Kareem M.W. , Habib Khairul , Sopian Kamaruzzaman
Published: January 2016

The investigation of solar air heater using SIMULINK tool to predict the transient state of solar thermal collector is presented in this article. The modeling is primarily centered on the solar crop drying system for small and medium scale farmers. Double transparent walls and sensible heat storage rocks were used in the modeling to aid the performance efficiency of the flat plate solar collector. The simulation was run with variable steps solver of relative tolerance of 0.001 using Dormand-Prince technique. The outcome of this investigation revealed the time trend of solar irradiance, effects of laminar forced convection on thermal coefficient, and early performance efficiency ratio. However, the model required improvement for it to accurately predict the system efficiency ratio after long period of operation.
Development of Water Hydraulic System
Authors: Saadun Mohd Noor Asril , Yusof Ahmad Anas , Ismail Mohd Syukran
Published: January 2016

Common hydraulic system using hydraulic oil as their working medium but there is an application using water due to high accessibility and environmentally concern.Water hydraulic is an attractive technology to use water as the pressure medium in hydraulic system. In this paper, water hydraulic system is design and develops that capable to use water as pressure medium. Water is used to provide clean environment and safe for the mobile purpose. The system includes electric motor, water pump, directional control valve, pressure control valve and motor hydraulic. Some of water challenged as the pressure medium in hydraulic system were considered during build and design the system to minimize the bad effect of water in hydraulic system. Besides, the arrangement of hydraulic components on the test rig also considered to optimize the water hydraulic system performance. Water hydraulic system performance was analyzed by measured maximum pressure produced from water pump and system efficiency. Others, the effect of temperature increment in water hydraulic system also analyzed to optimize operation time.
Fabrication of Lotus-Type Porous Copper Using Slip Casting and Sintering Techniques for Heat Pipe Applications
Authors: Supriadi Sugeng , Putra Nandy , Ariantara Bambang , Sunaryo Sunaryo , Rahmanto Dadit D.
Published: January 2016

A lotus type-porous copper will be used to substitute wick materials from tabulate coral capillary for heat pipe applications. The lotus type-porous material are normally fabricated using Gasar process, in which unidirectional solidification was applied to the metal-eutectic systems to obtain long cylindrical pores in the direction of solidification. A new process is proposed to fabricate the lotus type-porous material using slip casting and sintering. As an initial work, this paper is aimed to obtain appropriate processing parameters of fabrication of lotus-type porous copper using slip casting and sintering techniques. Nylon strings were used as pore formers to form cylindrical pores. They were coated with copper slurry consisting of copper powder and binding agent. The coated nylon strings were arranged in a mold and the slurry were poured. After drying, these castings were sintered at various sintering temperatures and sintering times. The results showed that starch as the binding agent is superior to PVA. The mixture of starch-water with starch content of 97%, the copper slurry with copper content of 50% by volume, the copper powder size of 200 µm, the sintering temperatur of 900°C, and the sintering time of 60 minutes are able to produce lotus-type porous copper similar to that produced through Gasar process.
Humidity and Water Effect on Wear Characteristics of Disc Braking System
Authors: Abdul Mokti Muhammad Faiz Fadzli , Abdul Hamid Mohd Kameil , Abu Bakar Abdul Rahim
Published: January 2016

A series of wet braking tests has been performed using two different pad materials. Brake tests were conducted in different operating conditions i.e. dry, humid air and wet environment in which both pad samples were tested against grey cast iron disc at certain sliding speed and contact pressure. Wear analysis was performed to find correlation between presence of water and changes in brake pad wear characteristics. The results revealed that regardless of the frictional behaviour, wear rate for both pad materials tested at humid air and wet braking is significantly lower than in dry results.
Improving the Efficiency of Poly-Crystalline Photovoltaic Module Using Special Transparent Glass Covers
Authors: Baradey Y. , Hawlader Mohammad Nurul Alam , Idres M. , Ihsan S.I.
Published: January 2016

Photovoltaic systems have become recently the most attractive and promising technology compared with other solar energy conversion devices. Solar energy reaches the earth’s surface in wavelengths between 0.300 and 2.50 μm. Silicon based photovoltaic systems convert only the wavelength between 0.35 to 0.82 μm of solar energy to electricity. The rest of incident solar radiation will be converted to heat, which will increase the operating temperature of the device and decrease the output power and efficiency. Maintaining the operating temperature of the PV systems at low and desired value was the main emphasis of different researches through the last decades. In this research, a special transparent glass cover (STGC) was used in order to cool down the photovoltaic module and, therefore, increase the output power and the efficiency of the module. The result showed that STGC led to 2.75% improvement in open circuit voltage, 9.6% increase in short circuit current, 26.4% increase in the output power, and 3% increase in the efficiency of the module.
Effects of the Optimized Resonator Dimensions on the Performance of the Standing-Wave Thermoacoustic Refrigerator
Authors: El-Fawal Mawahib Hassan , Mohd-Ghazali Normah , Yaccob Mohd Shafiek
Published: January 2016

Thermoacoustic refrigerator is an alternative cooling system, which is environmentally safe due to the absence of any refrigerants. The resonator tube of the system is of great importance; its design and dimensions influence the design and performance of the entire refrigerator. This work describes the design of the stack and the resonator along with the influence of its dimensions on the performance of the standing-wave thermoacoustic refrigerator. The resonator consists of two tubes, one larger than the other, characterized by the diameter ratio of the smaller over the larger diameter. A Lagrange multiplier method is used as a technique to optimize the coefficient of performance (COP) of the system. Results show that the resonator small diameter tube dissipates a minimum acoustic power at a diameter ratio of 0.46, which is 17 percent less than the published values. Moreover, the results show that the resonator length increases gradually with the increase of the mean design temperature which leads to the increase of the total acoustic power dissipated by the resonator, reducing the COP of the standing-wave thermoacoustic refrigerator.
Measurement of Thermoelectric Potential Coupling Coefficient for Sandstone Rock Sample
Authors: bin Jaafar Mohd Zaidi , Ismail Abdul Razak , bin Saharuddin Mohamad Kamil , binti Mohd Anuar Siti Mardhiah , bte Suradi Siti Rahmah , binti Omar Shaziera
Published: January 2016

Excessive water production is one of the main problems that occur during hydrocarbon production. During water injection, the less viscous water which has higher mobility than the reservoir fluid, tends to by-pass the oil. This phenomenon is normally called water fingering. Density difference between denser water and oil makes the water segregate to the bottom of layer, creating water tongue. Uncontrolled excessive water production will reduce oil production potential and increase the cost for water management and treatment. This phenomenon is economical unfavorable. Intelligent well integrated with monitoring systems and inflow control valve (ICV) has been applied in producing hydrocarbon. The excessive flow of water into well can be controlled using ICV. There are various methods and approaches been proposed to control water production. One of them is by measuring the spontaneous potential (SP) using permanent sensor outside the insulated casing. However, thermoelectric (TE) potential could also contribute to the measurement of the SP. The main objective of this experiment is to measure TE potential across sandstone rock sample at four different salinities which are 0.001M, 0.01M, 0.1M, and 1.0M of brine (NaCl). The core samples dimension is 7.62 cm in length and 3.81 cm in diameter. Temperature difference up to 80°C was applied to rock sample inducing different TE potentials at different salinities. Gradual heating technique was applied in creating temperature difference by using a temperature controller. Three different experiments were conducted for each salinity and real-time voltage (V) and temperature (T) were recorded using data acquisition system. Then the TE coupling coefficient can be determined by calculating the slope after plotting Voltage versus Temperature Difference. The result is as the salinity increases, TE coupling coefficient decrease and drop to zero around 0.1M. The result shows small but still measurable thermoelectric coupling coefficients.
Modeling of Light Propagation and Phonon Conduction inside Metallic Nanoparticles Enhanced Thin-Film Solar Cells
Authors: Lai Jia Jiun , Bong Victor N.S. , Wong Basil T. , Mustapha Khameel B.
Published: January 2016

The main aim of this work is to analyze the various heat transport mechanisms and their roles in efficiency enhancement of a thin-film solar cell due to embedded metallic nanoparticles at the rear of the cell, from both electrical and thermal aspects. The nanoparticles present deep inside the cell reflect incident radiation which then increases the optical path length for enhanced electricity generation. The increase in the optical path length also tends to induce additional but undesirable thermal heating which reduces the performance of the cells. The relationship between the improved conversion efficiency and the thermal effect is the crucial factor of maximizing the performance of thin-film solar cells and has yet to be explored. An accurate theoretical/numerical modeling is warranted in this case. Here, we present an analysis of combined light propagation and preliminary phonon transport in the cell to study solar-energy deposition and the associated thermal gradient.
Modeling the Bending Behavior of Single-Walled Cubic Zirconia Nanotubes
Authors: Muhammad Ibrahim Dauda , Awang Mokhtar
Published: January 2016

The bending behavior of single-walled cubic zirconia nanotubes (CZNTs) is studied in this paper based on a three-dimensional finite element analysis with molecular bonds modeled as structural beam elements and positioned at the joints of beams as substitute of atoms. In order to simulate the bending effect of CZNTs, the free-end is exposed to varying transverse displacements and the maximum force along the cross section at the fixed end is recorded to estimate the bending elastic modulus. The result obtained indicates that the bending elastic modulus of CZNTs depends on chirality and magnitude of applied transverse displacement. The simulated bending modulus of CZNTs fluctuates with the optimum value obtained from the zigzag configuration when 0.5 – 1.0 nm transverse displacement was applied. The results follows similar trend with what was obtained in other studies for carbon nanotubes but at comparatively lesser magnitude.
Effect of Multilayer Nanocomposite TiAlSiN/TiSiN/TiAlN Coating on Wear Behavior of Carbide Tools in the Milling of Hardened AISI D2 Steel
Authors: Caliskan Halil , Celil Celil Cagatay , Panjan Peter
Published: January 2016

Thin hard coatings are widely used in the protection of cutting tools, dies and molds to prolong their wear resistance and lifetime. Superior properties of different coatings can be combined with multilayer design, and especially a higher microhardness can be obtained by nanocomposite structures. In this study, a multilayer design composing of TiAlSiN, TiSiN and TiAlN layers was applied on carbide cutting tools. The top TiAlSiN layer has a nanocomposite structure of crystalline fcc-TiAlN and amorphous Si3N4 phases. The multilayer nanocomposite TiAlSiN/TiSiN/TiAlN coating was deposited on the carbide cutting tool using an industrial magnetron sputtering system. Wear behavior of the coated tools was investigated in the milling of hardened AISI D2 steel (~55 HRc). The changes in tool wear and surface roughness as a function of cutting distance were recorded. Wear mechanisms and types were investigated using optical and scanning electron microscopy in combination with energy dispersive spectroscopy. It was found that the multilayer nanocomposite TiAlSiN/TiSiN/TiAlN coating provides at least 1.2 times higher wear resistance and a longer lifetime than single layer TiN and TiAlN coatings. Main wear mechanisms are abrasion and adhesion of the workpiece material on the cutting edge. As a result, wear types are notch wear and build-up-edge formation.
Editorial Message
Authors: Rajapakse Rohan
Published: January 2016

No abstract available.Journal of the University of Ruhuna 2015 3(1): 1
Weedy rice: A threat to rice production in Sri Lanka
Authors: Ratnasekera Disna
Published: January 2016

Weedy rice (Oryza sativa L. f. spontanea), one of the four most significant weeds, is globally well known as a problem in the rice industry. The economic and environmental problems they pose include those related to rice crop production, milling for commerce, quarantine regulations and seed trade. Weedy rice possesses a number of common features with other weeds and distinctive characteristics such as phylogenetic and morphological resemblance to cultivated rice. Weedy rice is a difficult-to-manage weed when coexists in rice ecosystems causing economic losses to rice. Currently, weedy rice has been found in nearly all the rice growing regions in Sri Lanka. The estimated rice yield losses caused by the infestation of weedy rice varied largely from 40% to 90%, depending on its density and degree of shattering in rice fields. Effective control of weedy rice must be taken into immediate consideration to secure rice production in the country. The promotion of the use of certified seed paddy without weedy rice contamination should be the immediate and key step in the implementation of efficient control mechanism followed by other integrated weed control measures to reduce the proliferation and limiting its distribution to non-contaminated areas. However, the outcome will be limited except all parties in the rice industry are unified and committed to control weedy rice. In contrary to all unfavorable impacts of weedy rice on rice production, high heritability values coupled with high genetic variability of its favorable characteristics could be considered in rice improvement programs and in broadening the rice gene pool. Journal of the University of Ruhuna 2015 3(1): 2-13
Influence of biophysical characteristics of brinjal varieties on the infestation of brinjal shoot and fruit borer, Leucinodes orbonalis Guenée
Authors: Niranjana R. F. , Devi M. , Shanika W. , Philip Sridhar R.
Published: January 2016

A study was conducted during summer 2014 (February – May, 2014) and Rabi, 2014 (September, 2014 - January, 2015) at Vegetable Research Station, Palur, Tamil Nadu, India to find the relationship between biophysical characteristics of brinjal genotypes and infestation of Leucinodes orbonalis by screening 35 germplasm of brinjal. Thirty five germplasm were planted in the field having three replications of 05 plants for each treatment. The biophysical characteristics of brinjal genotypes viz., shoot thickness at 2.5 cm below the tip, number of trichomes on under surface of leaves, length of pedicel, calyx and fruit, and diameter of fruit were measured to correlate them with level of infestation by L. orbonalis. At the time of harvesting the per cent infestation of fruit were calculated. The results revealed that the shoot infestation by L. orbonalis negatively, but not significantly correlated with number of trichomes on leaves (r = -0.52) and positively correlated with shoot thickness (r = 0.05). Fruit infestation was positively but not significantly correlated with length of pedicel (r = 0.03) and calyx (r = 0.24) whereas non-significant and negative correlation was recorded between fruit infestation and fruit characters viz., length of fruit (r = -0.25) and diameter of fruit (r = -0.04). The shape and colour of fruit had no significant influence on the level of infestation Journal of the University of Ruhuna 2015 3(1): 21-28
Gastrointestinal stromal tumor and extragastrointestinal stromal tumor: Rare pattern of recurrence of disease
Authors: Ray Amitabh , Agarwal Vikash , Khan Enam , Ghosh Saurav , Goyenka Mahesh
Published: January 2016

GIST and EGIST are known to be distinct clinico-pathological entities. The occurrence of both in the same patient as a pattern of recurrence is extremely rare. We report one such case which was managed successfully due to high index of suspicion and interdisciplinary co-ordination.
Unresected pediatric myoepithelial carcinomas treated with alternating chemotherapy cycles with adjuvant radiotherapy
Authors: Dorbad Michael , Lim Peter Paul , Taylor Jeffrey
Published: January 2016

Myoepithelial carcinomas of soft tissue origin are rare tumors in the pediatric population. Due to the rarity of this malignancy, very few cases have been reported in the literature, and a consensus on treatment has not been established. Most myoepithelial carcinomas of soft tissue present in the extremities and are treated with surgical excision followed by adjuvant radiotherapy. We report 2 cases of pediatric myoepithelial carcinoma presenting with vertebral involvement making complete surgical removal impossible. These patients underwent chemotherapy and adjuvant radiotherapy as the main treatment for their primary tumors.
Serrated adenoma of stomach: A premalignancy?
Authors: Ail Divya Achutha , Kumar Hemamaheswari , Prakash Geetha , Selva Preethi , Nagalakshmi J.
Published: January 2016

Serrated adenoma is a newly described entity in the group of gastric adenomas. Until date only 20 cases of gastric serrated adenoma have been reported. It is an important entity to be diagnosed accurately as it has a very high-risk of malignant transformation, especially those located in the cardia of stomach. Serrated adenoma associated with adenocarcinoma is more frequent in the elderly, but pure serrated adenoma is common in the young, in whom follow-up is mandatory. Gastric serrated adenoma has distinct location, definite histomorphology and characteristic Ki-67 immunohistochemical staining. Ki-67 staining helps to differentiated pure serrated adenoma from those associated with adenocarcinoma. We present a young adult male, incidentally detected to have gastric serrated adenoma.
Monodromy Action on Unknotting Tunnels
in Fiber Surfaces
Authors: Banks Jessica , Rathbun Matt
Published: January 2016

In a 2012 paper, the second author showed that a tunnel of a tunnel number one, fibered link in S3 can be isotoped to lie as a properly embedded arc in the fiber surface of the link. In this paper we observe that this is true for fibered links in any 3-manifold, we analyze how the arc behaves under the monodromy action, and we show that the tunnel arc is nearly clean, with the possible exception of twisting around the boundary of the fiber.
The Poincaré–Deligne Polynomial of Milnor Fibers of Triple Point Line Arrangements is Combinatorially Determined
Authors: Dimca Alexandru
Published: January 2016

Using a recent result by S. Papadima and A. Suciu, we show that the equivariant Poincaré– Deligne polynomial of the Milnor fiber of a projective line arrangement having only double and triple points is combinatorially determined.
Bott type periodicity for the higher octonions
Authors: Kreusch Marie
Published: January 2016

We study the series of complex nonassociative algebras

\mathbb O_{n}

and real nonassociative algebras

\mathbb O_{p,q}

introduced in [10]. These algebras generalize the classical algebras of octonions and Clifford algebras. The algebras

\mathbb O_{n}

and

\mathbb O_{p,q}

with

p+q=n

have a natural

\mathbb Z_2^n

-grading, and they are characterized by cubic forms over the field

\mathbb Z_2

. We establish a periodicity for the algebras

\mathbb O_{n}

and

\mathbb O_{p,q}

similar to that of the Clifford algebras

\mathrm {Cl}_{n}

and

\mathrm {Cl}_{p,q}

.
Understanding the Relationship between Incentive Design and Participation in U.S. Workplace Wellness Programs
Authors: Batorsky Benjamin , Taylor Erin , Huang Crystal , Liu Hangsheng , Mattke Soeren
Published: January 2016

Purpose.

We aimed to understand how employer characteristics relate to the use of incentives to promote participation in wellness programs and to explore the relationship between incentive type and participation rates.

Design.

A cross-sectional analysis of nationally representative survey data combined with an administrative business database was employed.

Settings/Subjects.

Random sampling of U.S. companies within strata based on industry and number of employees was used to determine a final sample of 3000 companies. Of these, 19% returned completed surveys.

Measures.

The survey asked about employee participation rate, incentive type, and gender composition of employees. Incentive types included any incentives, high-value rewards, and rewards plus penalties.

Analysis.

Logistic regressions of incentive type on employer characteristics were used to determine what types of employers are more likely to offer which type of incentives. A generalized linear model of participation rate was used to determine the relationship between incentive type and participation.

Results.

Employers located in the Northeast were 5 to 10 times more likely to offer incentives. Employers with a large number of employees, particularly female employees, were up to 1.25 times more likely to use penalties. Penalty and high-value incentives were associated with participation rates of 68% and 52%, respectively.

Conclusion.

Industry or regional characteristics are likely determinants of incentive use for wellness programs. Penalties appear to be effective, but attention should be paid to what types of employees they affect.
Whole issue
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Published: January 2016

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