bluuebunny/crossref_metadata_2025 huggingface dataset:
An experimental study of the temperature evolution of a single fin submerged in a phase changing material during melting at different heat fluxes
Authors: Tassenoy R , Beyne W , Plas W , Lecompte S , De Paepe M
Published: December 2021

An experimental setup has been designed to study a single cylindrical fin placed in a cylindrical enclosure filled with phase changing material (PCM). The heat flux to the fin is measured at the top of the fin. The temperature evolution at different fin heights is measured by thermocouples placed internally in the fin. The evolution of these temperatures has been studied for different heat fluxes. This provides insight in the contribution of the different fin heights to the total heat transfer to the PCM during the different stages of the melting process. As such they can be used to assess the effectiveness of the fin over its length. After approximately 6h, the fin temperature stabilizes during melting. Due to the temperature drop over the fin, the bottom temperature reached is significantly lower than the temperature at the top and the contribution of this lower part to the total heat transfer is lower as well. For heat fluxes higher than 3805±75 W/m2, the steady-state temperatures at fin locations in contact with the melting PCM are similar. For low heat fluxes, this steady-state temperature is not reached during a 12h experiment. Longer experiments are thus needed to study the steady-state behaviour at these lower heat fluxes.
Numerical approach for fluids flow and thermal convection in microchannels
Authors: Ajeeb Wagd , Oliveira Monica S A , Martins Nelson , Sohel Murshed S M
Published: December 2021

The heat transfer performance of conventional thermal fluids in microchannels is an attractive method for cooling devices such as microelectronic applications. Computational fluid dynamics (CFD) is a very significant research technique in heat transfer studies and validated numerical models of microscale thermal management systems are of utmost importance. In this paper, some literature studies on available numerical and experimental models for single-phase and Newtonian fluids are reviewed and methods to tackle laminar fluid flow through a microchannel are sought. A few case studies are selected, and a numerical simulation is performed to obtain fluid flow behaviour within a microchannel, to test the level of accuracy and understanding of the problem. The numerical results are compared with relevant experimental results from the literature and a proper methodology for numerical investigation of single-phase and Newtonian fluid in laminar flow convection heat transfer in microscale heat exchangers is defined.
Conjugate heat transfer from a microchannel embedded impingement cum film cooled-flat plate
Authors: Jaiswal A K , Mahapatra P S , Prasad B V S S S
Published: December 2021

A computation fluid dynamics analysis is presented to investigate the effect of placing a microchannel inside a flat plate. A microchannel embedded flat plate with 250 angled 175 film holes in staggered form is considered in the present work. A Conjugate heat transfer analysis is done to determine the efficiency of cooling. Simulations were carried out, and subsequently, a parametric study was conducted to observe the effect of variation of blowing ratios. The temperature distribution is observed to be more uniform due to the presence of the microchannel, resulting in a lesser thermal gradient in the solid plate. It is also noted that overall effectiveness increases with the blowing ratio. The maximum increase in overall effectiveness due to the microchannel is about 30% for the blowing ratio of unity.
Critical evaluation of nanofluids and ionanocolloids as heat transfer fluids
Authors: Fabre Elaine , Sohel Murshed S M
Published: December 2021

Nanofluids and ionanocolloids are potential heat transfer fluids with remarkable thermophysical properties. The main difference between these two types of fluids remains in the base fluid used, which significantly impacts their performances. In this work, an attempt of a critical evaluation of the most relevant characteristics of both fluids is presented and the main challenges of their application are discussed.
Effect of Nanoparticle Deposition on the Thermal Performance of Evaporator in Thermosyphons
Authors: Donepudi T , Korobko A V , Peeters J W R , Fateh S
Published: December 2021

Rapid advancements in technology have led to the miniaturization of electronic devices which typically dissipate heat fluxes in the order of 100 W/cm2. This has brought about an unprecedented challenge to develop efficient and reliable thermal management systems. Novel cooling technologies such as Two-Phase Thermosyphons that make use of nanofluids provide a promising alternative to the use of conventional systems. This article analytically estimates the effects caused by nanoparticles that deposit on the evaporator surface and their effect on the heat transfer process.
A numerical method based on domain decomposition to solve coupled conduction-radiation physics using parallel computing within large porous media
Authors: Kumar Atin , Vicente Jérôme , Daurelle Jean-Vincent , Favennec Yann , Rousseau Benoit
Published: December 2021

A domain decomposition approach is developed to solve coupled conductive– radiative heat transfer within highly porous materials. In this work, a Kelvin–cell foam with five cells in each direction which has ˇ15.6 × 106 of voxels is considered. The coupled heat transfer is solved using the finite volume method where deterministic ray tracing is used to calculate radiative exchange. The temperature distribution is computed and cross–validated with the distribution obtained using a commercial software STAR–CCM+.
Experimental thermal performance comparison of pure and metal foam-loaded PCMs
Authors: Silvestrini M , Falcone M , Salvi F , Naldi C , Dongellini M , Morini GL
Published: December 2021

The thermal performance of latent heat thermal energy storage (LHTES) systems considerably depends on thermal conductivity of adopted phase change materials (PCMs). To increase the low thermal conductivity of these materials, pure PCMs can be loaded with metal foams. In this study, the melting process of pure and metal-foam loaded phase change materials placed in a rectangular shape case is experimentally investigated by imposing a constant heat flux at the top. Two different paraffin waxes with melting point of about 35°C are tested. The results obtained with pure PCM are compared with those achieved from the use of PCM combined with two different porous metals: a 10 PPI aluminum foam with 96% porosity and a 20 PPI copper foam with 95% porosity. The results demonstrate how metal foams lead to a significant improvement of conduction heat transfer reducing significantly the melting time and the temperature difference between the heater and PCM.
An estimate of size of copper nanoparticles levitating over the melt surface using the measurements of spectral reflectance
Authors: Dombrovsky Leonid A , Mendeleyev Vladimir Ya
Published: December 2021

A strong decrease in normal reflectance of a probe laser beam of 660 nm wavelength reflected from the surface of copper sample just after the beginning of the sample melting in a rarefied argon atmosphere has been observed recently by the authors. A similar time dependence of the reflectance is obtained in the laboratory experiments of the present paper at the wavelengths of 532 nm. The additional spectral measurements enable the authors to estimate the size of condensed nanoparticles levitating over the copper melt.
Numerical simulation of coupled diffuse radiation and natural convection in a cubic cavity heated from bottom
Authors: Chanakya Ganaparthi , Kumar Pradeep
Published: December 2021

We present, a three-dimensional numerical simulation of coupled natural convection with diffuse radiation in a cubic cavity whose all four vertical walls are isothermal, the bottom wall is convectively heated and the top wall is insulated. All walls are treated as black, diffuse and opaque for radiation. The simulations are carried out for the fixed Rayleigh (Ra=105) and Prandtl numbers (Pr=0.71) for a transparent and participating medium. The flow visualization technique Q-criteria has been used for analysis of the flow structure. The isothermal surfaces inside the cavity form vertical co-axially convergent-divergent three-dimensional open and closed nozzles, while inside the cavity Q-criteria reveals the formation of Jellyfish like flow structure. The cavity contains four conical vortices whereas each vortex is occupied in tetrahedron space.
Analysis of damaged Alumina Enhanced Thermal Barrier
Authors: Brodzik Ł
Published: December 2021

The paper presents the problem of aerodynamic heating of a damaged Alumina Enhanced Thermal Barrier AETB. At the given minimum dimensions of the cover layers, the impact of damage size on the temperature increase on the skin surface was analyzed. The aim of the study was to determine the temperature curve as a function of the size of damage. In the calculations FreeFem ++ non-commercial environment was used.
Radiative heat transfer calculation for mixture of gases using full spectrum k-distribution method
Authors: Khemani Kamal , Kumar Pradeep
Published: December 2021

The full spectrum k-distribution method is used to obtain radiative heat flux and divergence of radiative heat flux for two test cases, containing mixture of CO
2 and H
2
O at different concentration and temperature keeping pressure constant. The k-distribution for mixture of gases is obtained from individual gas k-distribution using three different mixing models, viz., superposition, multiplication and hybrid model. Further, the radiative transfer equation (RTE) is solved by the finite volume discrete ordinate method (FVDOM) to obtain the radiative flux and the radiation source term. The results obtained were compared with the FSK from spectral addition and LBL method. The multiplication mixing model provides better accuracy compared to other mixing models considered in the present study.
Assessment of engineering gas radiation methods in an industrial glass furnace configuration
Authors: Galtier M , Woelffel W , André F , Solovjov V P , Webb B W , Roy S
Published: December 2021

This work is dedicated to a comparison of various methods of gaseous flames radiation in a tri-dimensional configuration representative of a glass furnace studied at Saint Gobain Research Paris.
Evaluation of stability and viscosity of [C2mim][DCA] based ionanocolloids
Authors: Pinto J , Fabre E , Murshed S M S
Published: December 2021

In the search for the optimization of heat transfer systems, Ionanocolloids (INCs) as we have termed here, have revealed as very attractive choices due to their increasingly potential applications in thermal energy areas. By definition, INCs are suspensions of nanoparticles (NPs) into Ionic Liquids (ILs). Besides a high degree of versatility and enhanced thermal properties, these new class of fluids are considered as green solvents due to their negligible vapor pressure, non-flammability and recyclability. Despite the great advantages of using these INCs, their industrial application is still a challenge due to low stability and high viscosity issues attributed to them. In this work, different Ionanocolloids were prepared by two-step method, using 1-ethyl-3-methylimidazolium dicyanamide ([C2mim][DCA]) together with deionized water as base fluids and 3 different NPs: Titanium(IV) Oxide, Silicon Oxide and Aluminum Oxide. The stability and viscosity of these mixtures were then evaluated and the results are reported.
Two-phase flow model of a horizontal symmetrical impacting T-junction
Authors: Van Heule X , Van Nieuwenhuyse J , De Paepe M , Lecompte S
Published: December 2021

A symmetrical distribution of the two-phase refrigerant mixture before the evaporator is crucial to achieve optimal performance of heat pumps. In a previous study experiments on two-phase flow in a horizontal symmetric impacting T-junction were conducted in our lab. The measurements performed include both pressure drop and phase distribution data of refrigerants. This data is unique as almost all previous experiments in literature investigate air-water flows. With this data a mechanistic model was constructed which is capable of predicting the phase distributions and pressure drop depending on the flow regime and the fluid properties. The model is capable of predicting 90% of the data with a maximum mean deviation of 5%.
3D gas-liquid interfaces and flow characteristics of two-phase flows in horizontal tubes
Authors: Zhang Jingzhi , Sunden Bengt , Wadekar Vishwas , Wu Zan
Published: December 2021

In order to investigate the characteristics of gas-liquid two-phase flows in horizontal mini circular tubes with inner diameters of 3.14 and 6.68 mm, a prism is adopted to improve the light path in the visualization experimental setup. The front and top views of air-water two-phase flow patterns in two tubes are captured synchronously based on the improved method. Three-dimensional gas-liquid interfaces, flow pattern maps, and void fraction are obtained. The experimental results show that tube diameters have significant effects on flow patterns transition lines in the flow pattern maps, but the void fractions are independent on channel sizes. The effect of gravity gradually decreases with decreasing tube diameter, while that of surface tension is enhanced. As a consequence, the proportion of annular flow in flow pattern map increases in mini tubes, while the reverse is true for the stratified flow whose proportion decreases dramatically in mini channels. The void fraction increases with increasing gas quality. Experimental void fractions obtained using the three-dimensional gas-liquid interfaces fit well with correlations in the open literature. The shape of PDF distributions varies with flow patterns, which could be used to identify flow patterns in industrial applications.
Digital holographic study of vapor transport of heavy hydrocarbon from heated well cavity
Authors: Shukla Digvijay , Panigrahi Pradipta Kumar
Published: December 2021

Thin film evaporative cooling is one of the liquid cooling technologies, capable of removing high heat flux with lower junction temperature due to the utilization of latent heat of vaporization. To understand the various transport processes involved in vapour phase during thin film evaporation, evaporation from a heated well cavity of diameter 3 mm and height 2 mm is studied using Digital holographic interferometry technique. A flat disk-shaped vapour cloud is appeared for heated as well as not- heated well surface case. This signifies radial outward natural convection instead of pure diffusion. A higher vapour concentration is obtained at each time instants for heated surface case due to the higher evaporation rate as compared to non-heated, ambient case.
Averaged energy-balance analysis of wavy micro-channels
Authors: Durantes Roxana , Moon Justin , Rafael Pacheco J , Pacheco-Vega Arturo
Published: December 2021

This study presents numerical simulations of the convective heat transfer on wavy micro-channels to investigate heat transfer enhancement in these systems. The goal is to extend the analysis of our previous work [1, 2], by proposing a methodology based on local and global energy balances in the device instead of the commonly used Nusselt number. The analysis is performed on a single-wave baseline micro-channel model that is exposed to a heat influx. The governing equations for an incompressible laminar flow and conjugate heat transfer are first built, and then solved, for representative models, under several operating conditions, by the finite element technique. From computed velocity, pressure and temperature fields, local and global energy balances based on cross-section-averaged velocities and temperatures enable calculating the heat rate at each section. Results from this study show that this so-called averaged energy-balance methodology enables an accurate assessment of the channel performance.
Room temperature Magneto-Caloric Refrigerator: system level analysis
Authors: Rajamani Keerthivasan , Der Meer Theo Van , Shahi Mina
Published: December 2021

A system consisting of magneto-caloric fluid, which releases (absorbs) heat in the presence (absence) of a magnetic field, is used to achieve refrigeration. Gadolinium is used as a magneto-caloric material. The influence of using water and galinstan as heat transfer liquid, on the refrigerator performance is numerically analysed by varying the mass flow rate of the magneto-caloric fluid, and MCM volume fraction (0.4 to 0.6). A cooling load upto 20 W at room temperature is obtained over a temperature difference of 0.5 K.
Experimental study of the thermal management process at low-temperature circulating charging of an adsorbed natural gas storage system
Authors: Chugaev Sergey , Strizhenov Evgeny , Men’shchikov Ilya , Shkolin Andrey
Published: December 2021

Adsorbed natural gas (ANG) technology is a promising alternative to traditional compressed (CNG) and liquefied (LNG) natural gas systems. Nevertheless, energy efficiency and storage capacity of ANG system strongly depends on thermal management of its inner volume because of significant heat effects occurring during adsorption/desorption processes. At the same time low-temperature charging of ANG system provides its higher storage capacity as well as increased fire and explosion safety due to lower operating pressure and “bound-state” of gas molecules with the surface of adsorbent. In present work, a prototype of low-temperature circulating charging system for ANG storage tank filled with shaped microporous carbon adsorbent was studied experimentally in wide ranges of pressures (0.5-3.5 MPa) and gas flow rates (8-18 m3/h).
Experimental study of heat transfer in adsorbed natural gas storage system filled with microporous monolithic active carbon
Authors: Strizhenov Evgeny , Chugaev Sergey , Men’shchikov Ilya , Shkolin Andrey , Shelyakin Igor
Published: December 2021

The study of the thermal state of the monolithic adsorbent layer and internal heat exchange processes during the circulating charging of an adsorbed natural gas storage system was carried out. The correlation between gas flow mode and the heat transfer coefficient between gas and adsorbent is determined under conditions of mass transfer.
Advanced Adiabatic Compressed Air Energy Storage design and modelling accounting for turbomachinery performance
Authors: Roncolato J , Zanganeh G , Jenny P , Scholtysik M , Jacquemoud E , Haselbacher A , Barbato M C
Published: December 2021

Energy storage plants are going to become a strategic asset in electric grids. This statement is confirmed looking at the increasing shares of renewables composing the energy portfolio of several nations. Therefore the power demand and production mismatches, caused by the intermittent nature of renewables, must be reconciled. Many energy storage solutions are available but Advanced Adiabatic Compressed Air Energy Storage (AA-CAES) plants have potentials similar to pumped hydro systems (PHS). A physical model was developed in Matlab-Simscape to simulate the dynamics of AA-CAES plants, implementing temperature-dependent air properties, efficiency maps for turbomachinery and realistic power ramps. Furthermore, start-up and shut-down phases and energy consumption during idle periods were accounted for. The model embeds a 1D Fortran code to model the detailed behaviour of a packed-bed TES. The grid-to-grid performance of an AA-CAES plant was determined and the assumptions implemented to take into account real turbomachinery behaviour are presented.
Passive system of cooling and refrigerant fluid circulation, assisted by capillary pumping
Authors: Sologubenko O , Hemrle J , Kaufmann L
Published: December 2021

We propose a concept design of a cooling system, primarily targeting gas-insulated switchgear enclosures which use a mixture of a refrigerant fluid, such as Novec™ 649, and a non-condensable gas for electrical insulation. The novel open-loop system relies on evaporative cooling assisted by capillary pumping, and refrigerant vapor condensation on the walls of the system enclosure. The results of experiments on a laboratory prototype are presented and discussed. Besides cooling, a major benefit of the system is in facilitating the circulation of the gas mixture in the enclosure.
Inorganic PCMs applications in passive cooling of buildings - A review
Authors: Adeel Hassan Hafiz Muhammad , Lund Ivar
Published: December 2021

Buildings consume around 40% of total world energy and are responsible for 30-35% greenhouse gas emissions globally. Latent heat thermal energy storage is one of the most promising techniques being investigated currently to reduce the thermal load of buildings. Different types of phase change materials (PCMs) i.e. organic, inorganic and eutectics with different thermophysical properties have been investigated for passive cooling of buildings showing great potential for saving energy. Due to their higher thermal conductivity and high heat storage capacity per unit volume, inorganic phase change materials take advantage over organic ones. They can be used as stand-alone heat storage systems for free cooling, embedded in building walls, windows, roofs and ceilings etc. Studies have shown that there are some drawbacks of inorganic PCMs as well like corrosion of container material, phase separation and supercooling which require solutions.
Performance analysis of a new system for night cooling of buildings on a full scale office room - CFD study
Authors: Lança M , Coelho P J , Viegas J
Published: December 2021

Night natural ventilation systems have been receiving increased attention in recent years because of their energy saving potential and environmental protection when used in passive instead of active cooling. A recently proposed novel system for cooling the building concrete slab is studied numerically in the present work. It consists of a new type of a Suspended Ceiling (SC) with a peripheral gap between it and the walls, combined with the positioning of the air supply and extraction grilles between the ceiling slab and the SC. The system relies only on night ventilation as a means for cooling down the structure of the building. This study focuses on the use of Computational Fluid Dynamics (CFD) to predict the airflow and thermal performance of this strategy and it is applied to a full scale office room. The calculations show that a SC with a gap can reduce the difference between the average temperatures at the end of the heating and the end of the cooling periods by 25% compared with the case of a full covered slab room scenario (tight SC). CFD proved to be a useful and accurate tool to predict indoor conditions in buildings.
Validation and calibration of dynamic energy models: energy audit of a public building
Authors: Bergero S. , Chiari A.
Published: December 2021

Detailed buildings energy audits require dynamic simulation models based on hourly input data. This paper presents the calibration and validation of an office building energy model for the heating and cooling services. Simulation are carried out by DesignBuilder software. Measured hourly heating and cooling energy supplied by the generation system are used for the calibration of the model. Employee behaviour with reference to occupancy profiles and indoor temperature settings is also considered. A good agreement between measured and simulated data is obtained for both heating and cooling seasons.
Estimation of local heat flux for turbulent flow in a helical coil tube by conjugate gradient method
Authors: Shah S , Parwani A K
Published: December 2021

Estimation of local heat flux is challenging in a helical coil tube heat exchanger due to the complex flow field developed by tube curvature. The heat flux has uneven distribution in the angular direction of the tube cross-section. The current research aims to estimate the local heat flux at the fluid-solid interface for the turbulent flow of water in a helical coil tube by solving the inverse heat conduction problem (IHCP). Conjugate gradient method (CGM) with an adjoint problem is used as an inverse algorithm. First, the commercial CFD software ANSYS FLUENT is used for solving the governing equations of continuity, momentum, and energy for turbulent flow to obtain the heat flux at the fluid-solid interface. This heat flux is used to determine the temperature distribution at the outer surface of the tube. The heat flux is then considered unknown and it is estimated by CGM algorithm with the developed in-house code in MATLAB. The result shows that the estimation of heat flux by CGM is very accurate.
Experimental analysis of the evaporation of a thin liquid film deposited on a capillary heated tube: estimation of the local heat transfer coefficient
Authors: Cattani L , Bozzoli F , Ayel V , Romestant C , Bertin Y
Published: December 2021

The aim of this work is to estimate the local heat flux and heat transfer coefficient for the case of evaporation of thin liquid film deposited on capillary heated channel: it plays a fundamental role in the two-phase heat transfer processes inside mini-channels. In the present analysis it is investigated a semi-infinite slug flow (one liquid slug followed by one single vapour bubble) in a heated capillary copper tube. The estimation procedure here adopted is based on the solution of the inverse heat conduction problem within the wall domain adopting, as input data, the temperature field on the external tube wall acquired by means of infrared thermography.
Numerical optimization of a multistage sorption compressor
Authors: Hamersztein A , Davidesko A , Tzabar N
Published: December 2021

Sorption compressors are driven by thermal cycles and have no moving parts, excluding some passive check valves. Such compressors are suitable for powering Joule-Thomson (JT) cryocoolers and can provide reliable and vibration free active cooling system with a potential for high reliability and long operating life. The thermal cycle consists of cooling and heating a sorbent material which is installed in a sorption cell, where the heating is obtained by an inner electric heater and cooling is obtained by the surrounding via the sorption cell envelope. The investigation and optimization of the sorption cells were conducted in previous work, at steady state conditions, by a one-dimensional heat and mass transfer numerical model. The current paper presents a dynamic numerical model of sorption compressors which consist of several sorption cells. The numerical model allows one to three compression stages, with any number of sorption cells at each stage. The model enables the investigation of dimensional parameters and operational parameters, and provides the low and high pressures, pressure fluctuations, and compressor’s efficiency. The current investigation focuses on a three-stage compressor for nitrogen, with low and high pressures of 0.2 and 8 MPa, respectively, and a mass flow rate of about 11 mg/s.
Drying And Extraction of Moringa Oleifera And Its Application In Wastewater Treatment
Authors: Ibrahim M , Ismail N , Chua BL , Adnan ASM
Published: December 2021

Conventional coagulants such as aluminum sulfate and ferric sulphate have proved to be harmful to human health as it may cause neurological diseases like Alzheimer and percentile dementia. These health concerns have led to the use of natural coagulants which are environmental friendly and not harmful to human health. In this study, Moringa Oleifera seeds are selected to study the preparation of the natural coagulant and further use it in dye wastewater treatment. The two important steps used in preparing the natural coagulants are drying of the raw materials and extraction of the protein content. Moringa Oleifera seeds were oven dried at 40°C, 50°C and 60°C and the drying data was recorded. The recorded data was then fitted into five thin layer kinetic models to obtain the most suitable drying temperature and its corresponding drying time. Using Microsoft Excel Solver 2011, values of (R2), (RMSE) and chi-square (X2 ) were calculated. Based on the highest value of (R2 ) and lowest value of (RMSE), Page kinetic model was selected. Moreover, for the selected Page kinetic model, values of (R2) and (X2) were also compared for all three temperatures and the temperature with the highest (R2) value and lowest chi-square value (X2) was selected as the most optimum drying temperature. The most optimum drying temperature for drying Moringa Oleifera seeds was obtained as 50°C as the seeds dried at this temperature holds the maximum protein content concentration which enhances its coagulation properties. Furthermore, the corresponding drying time of about 6.5 hours for seeds dried at 50°C was also taken as the most optimum drying time. In the next step, Moringa Oleifera seeds which have been dried at 50°C for 6.5 hours were used for protein extraction. Solid to solvent ratios of 0.5:100, 1:100, 2:100 and 5: 100 (g of dried Moringa oleifera seeds: ml of distilled water) were used to extract the protein by using a domestic blender for 2 minutes. Using the Bradford method, the absorbance for each solid to solvent ratio solution was recorded and the protein content concentration was further calculated. The highest protein content concentration of 0.0017 ug/uL was obtained in the best solid to solvent ratio which is 5.0: 100. Therefore, this solid to solvent ratio was used in the jar test. The jar test was based on three process parameters which includes coagulant dosage, pH and initial concentration of dye wastewater. The coagulant dosage of 300 mg/L, initial concentration of dye wastewater of 50 ppm and pH of 7 were selected as the most optimum process parameters for a maximum turbidity removal of 70.4% and a maximum color removal of 44.54% in the dye wastewater treatment with Moringa Oleifera seeds.
Design of a compact grinding machine
Authors: Ashvinderjit S , Kelvin Chew W J
Published: December 2021

The availability and cost of tools are among concerns to the public and industries as key operation device used either for commercial or maintenance purposes such precision grinders or polishing machines are usually expensive. Assorted grinding tools in the market differ in terms of cost, required user proficiency levels and have different tool designs that can lead to limitations of flatness of ground surface and significant vibrations with prolonged use. The aim of this study is to develop a design compact grinder that is able to perform precise grinding and polishing while being cost efficient. Both functionality and ergonomic aspects were taken into consideration with market standards derived from datasheets. An initial design of the grinding machine was made using SolidWorks CAD software. A prototype was subsequently constructed and tested by using typical metallurgical sample preparation process with test parameters of grade of grinding paper and usage of lubricant. Microscopic image of ground specimens showed improvement in the quality of grinding with emery paper grades from coarse to fine grits with lubricant during the grinding process. Moreover, the designed compact grinding machine showed better surface finish when compared to using a typical angle grinder on aluminium sample.
Numerical simulation of segmented ratio in bismuth telluride and skutterudites for waste heat recovery
Authors: Cheong K W , Lim J H
Published: December 2021

The thermoelectric performance of the segmented annular thermoelectric generators with the bismuth telluride and skutterudites has been investigated. The effect of the length ratio of the hot-segment leg to total length leg on the thermoelectric performance of the segmented annular thermoelectric generators is analysed and discussed and the optimization design of the annular thermoelectric generator with bismuth telluride and skutterudites as the materials with high thermoelectric performance is obtained. The result of the thermoelectric performance with the manipulated variable of the increase of length ratio, the output power, output voltage and efficiency of the segmented annular thermoelectric generators increase at the beginning then decrease afterwards. Additionally, to compare with the single bismuth telluride and skutterudites annular thermoelectric generators, the output voltage, output power and the conversion efficiency of the segmented annular thermoelectric generators can be improved twice. Lastly, the thermoelectric performance of the segmented annular thermoelectric generators operating in the changes of the temperature. The result has proved that as the temperature increase, the thermoelectric performance of the annular thermoelectric generator will also increase. Hence, the acquired results may be given some useful applications of the bismuth telluride and skutterudites on the segmented annular thermoelectric generators for waste heat recovery.
A Numerical Assessment of the Efficacy of a Topography Design with Increasing Gradient Complexity for Filtering Biofouling Material through the Membrane Module of a Water Treatment System
Authors: Felicia WYM , Esmond LMZ
Published: December 2021

Biofouling can also be defined as the micro- / macro- organisms stuck on the surface that has been submerged in water. This is normally found in marine industry and water treatment industry. There are 3 ways of antifouling where the 3rd method surface modification was the main point to be focused on. Surface modification has high potential for antifouling performance and is not harmful to the ecosystem. In this research study was to find out the efficacy of antifouling performance with increasing the gradient complexity. The 2 models used were smooth topography and circular topography and have been manipulated and simulated with WorkBench 2020, Computational Fluid Dynamic (CFD). The results were simulated with the correct meshed and models. The simulated results were converged and 2 hydrodynamic variables; velocity and wall shear were used to check the efficacy of antifouling performance.
Chemically modified polystyrene co-loaded with antimicrobial agents
Authors: Koh Y X , Choo H L , Wong Y H , Yeong C H
Published: December 2021

A recent study showed that at least 50% of nosocomial infections are due to medical indwelling devices like surgical guides and prosthetics. This amounts to about 2 million patients affected a year. The reason for such statistics is the growth of microorganisms on the surfaces of the medical devices. There have been many attempts to create antimicrobial materials but most materials are unable to hold more than one antimicrobial agent without a secondary process. The study related to antimicrobial material with more than one type of agent is rarely found in literature. Hence, the objective of this project is to produce an antimicrobial material that can hold more than one antimicrobial agent without the need for a secondary process. The material is produced by sulfonating high impact polystyrene (HIPS) and attaching copper and silver ions. The optimum time of sulfonation of the HIPS was determined by the degree of sulfonation and ion exchange capacity. Then, the sulfonated HIPS were loaded with both copper and silver ions at different ratios. The 6-hour sample yielded the highest degree of sulfonation and ionic exchange capacity of 33.7% and 2.57 meq/g, respectively. In future work, the characterization of the 6-hour sulfonated HIPS sample loaded with copper and silver ions at different concentration ratios will be performed using TGA, DSC and FTIR spectroscopy. Lastly, the efficacy of the antimicrobial properties of the sulfonated HIPS will be tested using different bacterial strains.
Analysis of a Cam-Follower Mechanism for a Passive Parallel Lower Limb Exoskeleton
Authors: Lim D V , Tien D T K , Chung E C Y
Published: December 2021

This project focused on the implementation of a novel cam-follower mechanism that was deemed to have good potential for practical application into a passive lower limb exoskeleton to determine its effectiveness in reducing the energy requirement of the user and its ability to match the walking gait of the user. The design of this novel-cam follower mechanism is inspired by the retractable mechanism of a ballpen. The cam follower mechanism was incorporated into a passive lower limb exoskeleton that was available prior to the study. Passive exoskeletons are intended to augment the load carrying capacity of the user through mechanical means instead of relying on external power. The walking gait study was conducted using physical testing. The mechanism was found to cause the user to bend below his natural centre of gravity a couple of times throughout the walking cycle. The user also had to stabilize himself from being rocked from side to side. Energy calculations were likewise conducted to investigate the energy consumption for a full cycle. The interchange among gravitational potential energy, spring potential energy and kinetic energy of the mechanism for a full walking cycle did not indicate possible advantage for the user.
A Study to Compare the Fouling Resistance and Self-cleaning Properties of Two-patterned Surfaces with an Un-patterned Control Surface
Authors: Wong F Y M , Mak M S
Published: December 2021

Biofouling is an unwelcomed phenomenon where unwanted biological matter adheres to surfaces with the presence of water, resulting in alteration to the properties of the surface. This affects many industries, especially the marine industry. Multiple biofouling control studies have been conducted to minimize damage and maintenance cost of these surfaces. With rising concerns on the toxicity of current control methods towards the environment, non-toxic methods shown to be effective are surface modifications such as self-cleaning or biomimetic textured surfaces. One of the biomimetic surfaces, shark’s skin has shown anti-fouling properties due to its surface riblets with low drag properties based on studies done. However, few researches are conducted to implement these biomimetic surface topographies for real anti-fouling applications. Therefore, this project explores the possibilities in implementing biomimetic surface topographies such as shark’s skin in real life applications using computational fluid dynamics (CFD) analysis and also to manufacture these surfaces using 3D printing methods. A computer-aided design (CAD) model of shark skin and un-patterned surface topographies are used to study the behavior of fluid over these surfaces in CFD fluent in ANSYS software. The hydrodynamic variable data such as wall shear stress over the surface topography is represented in a contour and vector plot, these results are then analyzed. According to the hypotheses, the biomimetic shark skin surface topography will show higher wall shear stress, indicating anti-fouling properties. In the next part of this project is the manufacturing of these surface, the goal is to provide a cheaper alternative to current micro-structured surface production methods such as photolithography. Additive manufacturing such as fused deposition modeling (FDM) 3D printing can potentially provide a manufacturing method with a much lower cost and time needed. Thus, 3D printing of the biomimetic shark skin surface topography will be carried out in this project to determine if FDM can provide a manufacturing solution to anti-fouling micro-topography surfaces.
Reduction of Energy Consumption for Tire Test Room
Authors: Ghazali M Z N M , Tien D T K , Lim S C , Sarmin K R
Published: December 2021

This article presents a software-implemented 3-dimensional simulated analysis of a 4-tire test room and the 6-tire test room. The results of the average performance through the simulated analysis of 100 iterations were obtained. The simulation showed the temperature distribution in the test rooms. This objective of this study was to assess the efficiency of the start-up process in each test room and to find the most efficient setup. A promising improvement would be to install the heaters at the bottom of the room under the drums instead of at the ceiling. The results of the simulation will be compared to the data of temperature logging of the tire test rooms once there is availability upon the lifting of the Covid pandemic lockdown restrictions.
Recycling Polymer Blend made from Post-used Styrofoam and Polyethylene for Fuse Deposition Modelling
Authors: Yap E P , Koay S C , Chan M Y , Choo H L , Ong T K , Tshai K Y
Published: December 2021

Styrofoam is widely used as packaging material for many applications like home furniture and electrical appliance. Styrofoam is a non-biodegradable material which its disposal causes serious environment issues. This research demonstrates an alternate recycling method of Styrofoam waste by converting it into 3D printing filament for Fused Deposition Modelling (FDM). For this research, the recycled polystyrene (rPS) was extracted from Styrofoam waste and blended with low-density polyethylene (LDPE), then extruded into filament using a filament extruder. The formulated rPS/LDPE blend with different blend ratio exhibited a good printability when the printing temperature and extrusion rate fixed at 240°C and 120%. However, the tensile strength of printed specimens with rPS/LDPE blends were lower than printed specimen with neat rPS. The tensile strength and modulus of printed specimens with rPS/LDPE were decreased due to the increase of LDPE content. The decrease of tensile strength mainly caused by the incompatibility between the rPS and LDPE phases. However, the addition of more LDPE content in the blend enhanced the ductility of rPS/LDPE blends. Furthermore, the increase of LDPE content also increased the thermal stability of rPS/LDPE blends. Overall, the rPS/LDPE blend is a potential alternate material for producing FDM filament.
Stability enhancement of power system with the implementation of power system stabilizer PSS and excitation system IEEE Type-1
Authors: Khujaev Abumuslim , Vaithilingam Chockalingam Aravind , Alsakati Ahmad Adel , Alnasseir Jamal
Published: December 2021

Stability of power system is an ability of an electric power system that reaches its stable condition after fault happens in its network. The system is unstable when one generator loses its stable synchronism performance. This paper investigates the transient stability of an IEEE 9-bus system during faults that happen in different bus locations. Additionally, the analysis contributes to the integration of the exciter IEEE type-1 for synchronous generator and integration of power system stabilizer (PSS) to improve the power angle stability in the power system. The fault at bus 4 has the highest amplitude in which it increases to 77.58 degrees for the power angle of Synchronous Generators (SGs). The absence of PSS showed that the existing system oscillated and it is unstable. However, the integration of PSS enables the system to damp the oscillations of power angle and reduce the settling time to 5.69 seconds during the fault at bus 4. Moreover, the PSS is connected to SGs through the excitation system to improve the stability of the system in relative power angle of SGs, speed deviation, and electrical power of SGs. Hence, the integration of PSS and excitation system enhances the transient stability of the power system.
Transient stability analysis of IEEE 9-bus system integrated with DFIG and SCIG based wind turbines
Authors: Ramlochun Brish , Vaithilingam Chockalingam Aravind , Alsakati Ahmad Adel , Alnasseir Jamal
Published: December 2021

Electricity is in high demand with a fast-growing population; hence it is advisable to turn towards green energy. In this research, Wind Turbine (WT) is modelled with two different types of induction generators (IGs), which are the Doubly-Fed Induction Generator (DFIG) and Squirrel-Cage Induction Generator (SCIG) and implemented to IEEE 9-Bus system to assess the transient stability. MATLAB/ Simulink R2019a platform was considered to carry the whole examination. DC1A excitation system was applied to Synchronous Generators (SGs) as well as Power System Stabilizer (PSS). The transmission line7-5 was found to suffer from a high peak value of a relative power angle of approximately 130 degrees. As for the settling time, without PSS it was 20.69 s and with PSS it became 6.23 s. A wind farm with a rated capacity of 60 MW was used in the system. WT integrated with DFIG has the lowest peak value of 127 degrees at Bus locations 4 and 5 and for SCIG, Bus 5 with a peak value of 136 degrees. Thus, it can be propelled as the perfect location. Moreover, this is due to the three-phase fault was located at the transmission line7-5 which is far away from Buses 4 and 5. In the end, the WT integrated with DFIG provides a lower peak value of relative power angle compared to SCIG, whereas for settling time, it is the opposite.
Real-time and automatic map stitching through aerial images from UAV
Authors: Goh J N , Phang S K , Chew W J
Published: December 2021

Real-time aerial map stitching through aerial images had been done through many different methods. One of the popular methods was a features-based algorithm to detect features and to match the features of two and more images to produce a map. There are several feature-based methods such as ORB, SIFT, SURF, KAZE, AKAZE and BRISK. These methods detect features and compute homography matrix from matched features to stitch images. The aim for this project is to further optimize the existing image stitching algorithm such that it will be possible to run in real-time as the UAV capture images while airborne. First, we propose to use a matrix multiplication method to replace a singular value decomposition method in the RANSAC algorithm. Next, we propose to change the workflow to detect the image features to increase the map stitching rate. The proposed algorithm was implemented and tested with an online aerial image dataset which contain 100 images with the resolution of 640 × 480. We have successfully achieved the result of 1.45 Hz update rate compared to original image stitching algorithm that runs at 0.69 Hz. The improvement shown in our proposed improved algorithm are more than two folds in terms of computational resources. The method introduced in this paper was successful speed up the process time for the program to process map stitching.
The numerical analysis of partial discharge activities of silicone rubber composites
Authors: Binti Khairul Azmin Raden Arni Aminorisha , Ahmad Hafisoh , Yap Hoon
Published: December 2021

This paper discussed on the partial discharge phenomenon occurs in insulating materials-based silicone rubber. In general, the partial discharges occur due to the presence of additional substances or void in the material. The methods that are used to study partial discharge are offline monitoring, online monitoring, and numerical analysis. The numerical analysis was performed on this silicone rubber compound with the introduction of three identical void with the radius of 1.15 mm. The simulation results show that the pure silicone rubber material experiences the high impact of partial discharge activities compared to the second material; microvaristor filled with silicone rubber.