bluuebunny/crossref_metadata_2025 huggingface dataset:
En route to metal-mediated and metal-catalysed reactions in water
Authors: Zhou Feng , Li Chao-Jun
Published: November 2018

This perspective report presents the key approaches for the development of various organometallic reactions in aqueous media.
Oxygen uptake in complexes related to [NiFeS]- and [NiFeSe]-hydrogenase active sites
Authors: Yang Xuemei , Elrod Lindy C. , Reibenspies Joseph H. , Hall Michael B. , Darensbourg Marcetta Y.
Published: November 2018

The NiFe hydrogenase biomimetics are protected from oxygen invaders by sulfur and selenium castle guards.
Clumpiness of the interstellar medium in the central parsec of the Galaxy from H2 flux–extinction correlation
Authors: Ciurlo A. , Paumard T. , Rouan D. , Clénet Y.
Published: November 2018

Context. The central parsec of the Galaxy contains a young star cluster embedded in a complex interstellar medium. The latter mainly consists of a torus of dense clumps and streams of molecular gas (the circumnuclear disk) enclosing streamers of ionized gas (the Minispiral).

Aims. In this complex environment, knowledge of the local extinction that locally affects each feature is crucial to properly study and disentangle them. We previously studied molecular gas in this region and inferred an extinction map from two H2 lines. Extinction appears to be correlated with the dereddened flux in several contiguous areas in the field of view. Here, we discuss the origin of this local correlation.

Methods. We model the observed effect with a simple radiative transfer model. H2 emission arises from the surfaces of clumps (i.e., shells) that are exposed to the ambient ultraviolet (UV) radiation field. We consider the shell at the surface of an emitting clump. The shell has a varying optical depth and a screen of dust in front of it. The optical depth varies from one line of sight to another, either because of varying extinction coefficient from the shell of one clump to that of another or because of a varying number of identical clumps on the line of sight.

Results. In both scenarios, the model accurately reproduces the dependence of molecular gas emission and extinction. The reason for this correlation is that, in the central parsec, the molecular gas is mixed everywhere with dust that locally affects the observed gas emission. In addition, there is extinction due to foreground (“screen”) dust.

Conclusions. This analysis favors a scenario where the central parsec is filled with clumps of dust and molecular gas. Separating foreground from local extinction allows for a probe for local conditions (H2 is mixed with dust) and can also constrain the three-dimensional (3D) position of objects under study.
Gaia-DR2 extended kinematical maps
Authors: López-Corredoira M. , Sylos Labini F.
Published: November 2018

Context. The Gaia Collaboration has used Gaia-DR2 sources with six-dimensional (6D) phase space information to derive kinematical maps within 5 kpc of the Sun, which is a reachable range for stars with relative error in distance lower than 20%.

Aims. Here we aim to extend the range of distances by a factor of two to three, thus adding the range of Galactocentric distances between 13 kpc and 20 kpc to the previous maps, with their corresponding error and root mean square values.

Methods. We make use of the whole sample of stars of Gaia-DR2 including radial velocity measurements, which consists in more than seven million sources, and we apply a statistical deconvolution of the parallax errors based on the Lucy’s inversion method of the Fredholm integral equations of the first kind, without assuming any prior.

Results. The new extended maps provide lots of new and corroborated information about the disk kinematics: significant departures of circularity in the mean orbits with radial Galactocentric velocities between −20 and +20 km s−1 and vertical velocities between −10 and +10 km s−1; variations of the azimuthal velocity with position; asymmetries between the northern and the southern Galactic hemispheres, especially towards the anticenter that includes a larger azimuthal velocity in the south; and others.

Conclusions. These extended kinematical maps can be used to investigate the different dynamical models of our Galaxy, and we will present our own analyses in the forthcoming second part of this paper. At present, it is evident that the Milky Way is far from a simple stationary configuration in rotational equilibrium, but is characterized by streaming motions in all velocity components with conspicuous velocity gradients.
Modelling Techniques Used in The Analysis of Stratified Thermal Energy Storage: A Review
Authors: Soomro Afzal Ahmed , Mokhtar Ainul Akmar , Akbar Ali , Abbasi Aijaz
Published: November 2018

Thermal energy storage plays an important role in the energy management and has got great attention for many decades; stratification is a key parameter to be responsible for the performance of the stratified thermal energy storage tank. In this paper detailed study of modelling techniques used to analyse thermal energy storage has been conducted. The division of literature has been made as numerical, analytical, and artificial neural network-based. Numerical modelling being very physical based and required more specific software’s tools remain costly and computationally very complex at the same time it provides the detailed insights into the system, analytical model provide the exact solutions but need some assumptions which make the system unrealistic in some cases but is easy and flexible in terms of computational requirements, ANN though recently used modelling technique is a black box model which merely needs the data rather than any physical based complex calculations is attracting the scientific community.
Smart energy management systems: a literature review
Authors: Loganathan N. , Mayurappriyan P.S. , Lakshmi K.
Published: November 2018

Recently smart energy management systems (SEMS) have been developed extremely fast. The significant methods facilitate SEMS to sustain system scheming via demand responses, possibly together with peak shaving and load changing as well as a few additional services. This paper reviews the thought of SEMS and looks into its environment. It highlights the SEMS most important apparatus and moderately analyzes a different technical approach. In adding together discuss a number of the concern and challenge as well as suggests a framework for prospect systems.
Thermo-mechanical behavior of epoxy composite reinforced by carbon and Kevlar fiber
Authors: Abasi Falak O. , Aabass Raghad U.
Published: November 2018

Newer manufacturing techniques were invented and introduced during the last few decades; some of them were increasingly popular due to their enhanced advantages and ease of manufacturing over the conventional processes. Polymer composite material such as glass, carbon and Kevlar fiber reinforced composite are popular in high performance and light weight applications such as aerospace and automobile fields. This research has been done by reinforcing the matrix (epoxy) resin with two kinds of the reinforcement fibers. One weight fractions were used (20%) wt., Epoxy reinforced with chopped carbon fiber and second reinforcement was epoxy reinforced with hybrid reinforcements Kevlar fiber and improved one was the three laminates Kevlar fiber and chopped carbon fibers reinforced epoxy resin. After preparation of composite materials some of the mechanical properties have been studied. Four different fiber loading, i.e., 0 wt. %, 20wt. % CCF, 20wt. % SKF, AND 20wt. %CCF + 20wt. % SKF were taken for evaluating the above said properties. The thermal and mechanical properties, i.e., hardness load, impact strength, flexural strength (bending load), and thermal conductivity are determined to represent the behaviour of composite structures with that of fibers loading. The results show that with the increase in fiber loading the mechanical properties of carbon fiber reinforced epoxy composites increases as compared to short carbon fiber reinforced epoxy composites except in case of hardness, short carbon fiber reinforced composites shows better results. Similarly, flexural strength test, Impact test, and Brinell hardness test the results show the flexural strength, impact strength of the hybrid composites values were increased with existence of Kevlar fibers, while the hardness was decrease. But the reinforcement with carbon fibers increases the hardness and decreases other tests.
The Effect of Flowrate and Effectiveness on Theoretical Design and Thermal Characteristic of a GHE
Authors: Yusof T.M. , Basrawi M.F. , Shahrani A. , Ibrahim H.
Published: November 2018

Ground heat exchanger is an exciting technique to reduce energy consumption in building especially in hot climate countries. Implementation of GHE for commercial unit in Malaysia is almost none in record. Thus, performance study of the GHE in Malaysia is crucial to be conducted either experimentally or numerically. Therefore, this paper presents the performance of GHE in term of effectiveness, outlet temperature and rate of heat transfer based on mathematical model. The model is developed based on cross flow heat exchanger with one fluid unmixed. There are two variable parameter used in the analysis which is effectiveness and flowrate of the air for 25 meter length of a PVC pipe. Three effectiveness values which is 0.8, 0.9 and 0.99 have been analysed in this study. Meanwhile, flowrate of air is ranging from 0.02 to 0.2 kg/s. Results show that flowrate at 0.02 kg/s gives great temperature reduction in the pipe compared with higher flowrate. However, flowrate of 0.2 kg/s produces higher cooling potential. Characteristic of the GHE for the rate of heat transfer with 80, 90 and 99 percent effectiveness also have been developed and it has been found that effectiveness of 0.9 provide good combination between flowrate and the rate of heat transfer for 25 meter length of the pipe
Effect of Grass and Coconut Shell Blending Ratio on the Performance of Syngas
Authors: Tamili Norazilah , Chuan Lee Kean , Sulaiman Shaharin A. , Moni Mohamad Nazmi Z. , Inayat Muddasser , Lo Michael Yin Kai
Published: November 2018

Biomass is a potential energy source since it is renewable, efficient and cost effective. Biomass can be converted in useful fuel gas via gasification method, which is an effective method to produce energy from biomass. Reliance on a single biomass to generate electrical power can cause disruption due to the inconsistencies in the supply of biomass feedstock. Co-gasification of biomass can mitigate the problem. This paper is aimed to investigate the synergetic effect on the syngas produce from co-gasification of biomass. Co-gasification of grass (G) and coconut shell (CS) was carried out to study the syngas performance. The characterization was carried out in order to understand the physical properties of biomass in relation to thermochemical conversion. The characterization results shows that both G and CS have an acceptable range of proximate and ultimate analysis. Both biomass materials were co-gasified at varied ratios of 50:50, 40:60 and 20:80 using an externally heated gasifier. The blend of G and CS at 20:80 ratio has positive synergetic effect as evident by increase in the gas composition for CO, CH4 and H2. It is concluded that co-gasification results of G and CS is possible.
Thermogravimetric analysis of empty fruit bunch
Authors: Chala Girma T. , Lim Ying P. , Sulaiman Shaharin A. , Liew Chin L.
Published: November 2018

This paper presents the characteristics of empty fruit bunch (EFB) using thermogravimetric analysis (TGA) and shows its potential as a renewable energy sources. A set of data were collected from the thermal reaction and plotted in mass or percentage of the initial mass against either temperature or time, respectively. In the thermogravimetric analysis, mass, temperature and time were considered as base measurements and important data for derivative thermogravimetric (DTG) curve were analysed while many additional measures could be derived from these three base measurements. It was observed that heating rate of 8.5°C/min and air flow rate of 85mL/min provided a maximum weight loss rate of 0.209%/°C at the temperature of 313.5°C and the derivative weight peak of -0.1895mg/°C at 292°C. The time taken to reach the maximum temperature of 899.9°C was 46.74 minutes, and ΔT endo-up reflected minimum point of -0.2°C at 15.82 minutes and maximum ΔT endo-up of 888°C at 42 minutes. Heat flow endo-up also showed that the minimum heat flow was 15.39mW at 15.85 minutes and reaching the peak heat flow endo-up of 47.73mW at 43.27 minutes.
Variable Speed Pump Performance Characteristics for Domestic Application
Authors: Jilani Aisyah , Razali Akhtar
Published: November 2018

Generally, water pumps work at a fixed speed. Structural resonance in fixed speed can cause vibration. The reason that most single speed pumps utilize an excessive amount of electricity is that they are overused and oversized. Therefore, this research is embarked to study the characteristic of a pressure-controlled variable speed pump, develop the variable speed pressure controlled pump and analyse the pump performance. A technique is proposed to change the constant speed pump to variable speed pump by adding Variable Frequency Drive (VFD) and microcontroller. A simple test rig is designed and fabricated represented of water distribution for domestic use. The method was then experimentally validated to verify the pump performance and energy used. Data for water flow rate, water pressure, power output and pump speed were analysed. Since the speed can be lowered until 29.27% which according to the water volume demands, therefore the power consumption was found decreased and the lowest power is 0.014 kW. Maximum water discharge capability is 32.38 lpm. It is found that, a variable speed water pump able to save energy up to 97% and led to electricity bill saving and increase the life span of pipes and joints through less hydraulic pressure built-up.
The Effect of Tube Length, Cold Exit Diameter and Working Gas on The Cold Flow Temperature of Vortex Tube
Authors: Suhaimi Muhammad Fadhli , Yusof Mohd Hazwan , Rashid Mohamad Nor Hafiz , Basrawi Mohamad Firdaus
Published: November 2018

A vortex tube is a simple device which works as a refrigerator, also known as Ranque Vortex Tube, Hilsch Vortex Tube, and Ranque–Hilsch vortex tube. It is used to obtain desired hot and cold gas and is widely used for spot cooling in industry. In vortex tube, the effect of geometrical parameters on the cold flow temperature of vortex tube is still unclear, and effect of certain working gas is unidentified. Hence, the objective of this analysis is to determine the effect of length of the vortex tube, cold exit diameter and different working gas. 3 different tube lengths, 3 different cold exit diameters, and 8 different types of gas are used. Simflow, which is free software, is selected to analyse the effect numerically. From the results, it is clear that the optimum tube length, cold exit diameter, and working gas are L = 175 mm, d = 4 mm and helium, respectively.
The Effect of Refrigerant Charge and Outdoor Temperature on the Condenser and Evaporator of a Split-Unit Type Air Conditioner Using R22 Refrigerant
Authors: Yusof Mohd Hazwan , Muslim Sulaiman Mohd , Suhaimi Muhammad Fadhli , Basrawi Mohamad Firdaus
Published: November 2018

To maintain the temperature setup on an air conditioner, the compressor will use more or less energy based on the outdoor temperature. Therefore, there is a need to understand the performance of the air conditioner if the outdoor temperature is varied. In this research, a used small capacity split-unit air conditioner using R-22 refrigerant is used to study the effect of outdoor temperature on the performance of the air conditioner. From the results, it can be understood that lower outdoor temperature requires less work from the compressor. The cooling capacity and coefficient of performance drop as the outdoor temperature increases.
Energy Efficient Blood Transfusion System
Authors: Rathi Abhishek , Das Gitesh , Monica Subashini M.
Published: November 2018

RBCs stand for red blood cells (also known as erythrocytes), are the most common type of blood cells. They are the basic means of delivering oxygen, in the vertebrates to different cells and tissues. Hemoglobin is a protein in the RBCs, which carries oxygen and gives blood its red color. The normal range of RBCs in men is approximately 4.7 to 6.1 million cells per microliter and the normal range of RBCs in women is approximately 4.2 to 5.4 million cells per microliter. For a person to be eligible to donate blood, he/she should have the minimum number of RBCs in their blood for donation. This is only possible when the minimum duration between two donations is 3 months, be- cause it takes RBC about three months to develop completely. Many equipment have been developed or installed in hospitals for reducing energy consumption and increasing the efficiency. But even after installing these energy efficient devices in hospitals, it has been found out that these devices face a number of difficulties or obstacles. Thus, this paper focuses in developing an energy efficient software for blood transfusion that can function without interfering with any obstacles and thus giving accurate results.
To design and develop a fuzzy based power flow controller for the stability improvement of a power system
Authors: Malini T. , Radhakrishnan G.
Published: November 2018

With the growth and development of power electronics in the field of power system enumerates the new and efficient forms of controlling the power. This paper deals with a systematic approach to design an Interline Power Flow Controller (IPFC) for multi-machine infinite bus power system is proposed. It is an independent controller system which is suitable for an individual line compensation of a multiline power system. A Simulink model of an IPFC based multi-machine system along with fuzzy is developed. The outcomes obtained were compared with the conventional method of tuning the proposed controller to confirm the effectiveness and robustness of the developed controller. The analysis of an IPFC is assuring the response towards the system’s operation. In this proposed scheme, the controller is designed with the series and shunt configuration of an interline power flow controller using fuzzy technology. The two types of configuration in the designed system are manipulated in which most of the compensation in a multiline system is provided by means of the series controller, the shunt controller which is used for the real power compensation. The simulation of a designed system is done using MATLAB software-Simulink.
Simulation Study on the Potential of Braided Hose Failure in Internal Combustion Engines
Authors: Hassan S. , Afdhal S. , Shahrizal M. , Eleena A.
Published: November 2018

In this study, damaged braided hoses was obtained from the actual site to investigate the possible causes of failure in the internal combustion engines. The hoses were assembled with polytetrafluroethylene (PTFE) as the inner tube and externally braided outer tube corrosionresistant steel (CRES). The hose had undergone failures near the end of the fittings. The braided hose was measured and modelled using SOLIDWORKS CAD software. The ANSYS static structural stimulation was used to measure the stress distribution on the hose due to pressure applied with various bend shapes. The simulation was done by fixing the end of the pipe and exerting the working pressure inside the inner layer of PTFE. The results of the simulation have shown that the inner tube experienced high stresses near the fittings which is then aggravated with the bending. With cyclic pressure loading, the hose was unable to stand the high stresses near the fittings and therefore failed. Further analyses were done to the braided hose to investigate the other possible of failure using failure analysis method.
Analysis on the Performance of a Prototype of Thermoelectric based Power Generation System
Authors: Elghool Ali , Naeem M.F. , Basrawi Firdaus , Ibrahim Hassan , Idris DMND , Habib Khairul , Yusof Mohd Hazwan
Published: November 2018

There are needs on electricity but people cannot get electricity including when doing outdoor activities at isolated areas, selling goods in night market and during disaster such as flood and earthquake. People need electricity especially for charging communication gadgets and lighting. Thus, the objective of this study is to develope and test the performance of a small prototype of thermoelectric generator (TEG) based power generation system. The TEG based power generation system developed consists of heat collector, thermoelectric generator, heat pipe and fin based heat sink, and DC-DC converter. The heat collector was designed to ensure the suitable temperature for the TEG which is should not exceed 320°C on the hot side. Heat pipes was used to increase the power output by lowering or maintaining the temperature at cold side, to ensure large temperature difference is obtained. The prototype was tested and data of temperature, voltage and current were collected. A cell phone was used during the test as a load to the system. All the data were recorded by using temperature data recorder, power meter and multimeter. It was found that the highest maximum power output was 7.7 watt at the temperature difference of 138°C. The output is sufficient to charge the cell phone and it is also possible to light an LED bulb. However, it did not achieve the maximum output of 43 W. This is a results of limitation of maximum electrical load (only one cell phone was used) and the limitation of the performance of the prototype. Thus, although the prototype is succesfully generate enough power to charge a cell phone, but improvement in heat sink design, and adding more electrical load are needed to get better results.
Dynamic inverse controller with Matrix Converter Drive Feed Three Phase Induction Motor
Authors: Keream Settar S , Abdalla Ahmed N , Daud Mohd Razali Bin , Koh Johnny
Published: November 2018

Dynamic inversion (DI) is a controller technique by which existing undesirable dynamics are cancelled out and changed by desirable dynamics. The application of induction motor drives with sinusoidal input currents a matrix converter combined with DI is used which directly connects a three-phase input voltage source to a three-phase (AC-AC converter) without dc-link components. This paper presents a novelty of using nonlinear dynamic inverse controller with matrix converter topologies on three phase induction motor. The efficiency of the converter and their modulation techniques for the implementation of the strategies is increased. The speed response tracking and torque ripple minimization is achieved. The robustness of the proposed method has been confirmed from simulation and experimental model.
Enhanced Cooling Process of Furnace Using Vortex Tube Cooling Device
Authors: Yusof Mohd Hazwan , Suhaimi Muhammad Fadhli , Azmi Izzat Muhammad , Harun Wan Sharuzi Wan , Basrawi Mohamad Firdaus
Published: November 2018

A furnace is a heating device, which is used for heating samples up to 1350°C. The conventional method to reduce the temperature of the furnace to room temperature requires more than 8 hours. Therefore, a vortex tube cooling device is used to enhance the cooling process. The vortex tube is a small cooling device that uses compressed gas to produce cold flow. In this study, 3 cooling methods were compared; the conventional method, room temperature compressed gas cooling method, and vortex tube cooling method. From the results, it is clear that the vortex tube is able to enhanced the cooling process. Comparing to the conventional method, the vortex tube can reduce the temperature 2-hour faster.
Enhancement of Power Quality in Multi Feeder Three Phase System with Photovoltaic fed ANFIS-Unified Multi Converter Controller
Authors: Sudheer Kasa , Sudha Ramasamy
Published: November 2018

Substantial growth in modern innovations demands more power from utility. To cope with drastic power demand on grid renewable sources have been integrated. This makes more complex power system as these integrated sources more dynamic in nature. Intelligent usage of renewable sources leads to optimal and reliable power structure. This paper provides an optimal usage of renewable source for unified controlling action to compensate power quality issues on multi distribution feeders. Proposed Unified Multi Converter Controller (UMCC) effectively alleviates power quality issues like harmonics, imperfections in current and voltage on multi feeder. ANFIS based harmonics alleviation is studied and compared with traditional control error tuning. Here, Photovoltaic source is considered. Proposed three phase system is analyzed in MATLAB\SIMULINK platform with variable load and supply voltage conditions.
Chassis dynamometer for electric two wheelers
Authors: Hassan Muhammad Hadi , Sapee Syazwana , Nafiz Daing Mohamad , Yusop Ahmad Fitri , Basrawi Mohamad Firdaus , Rasid Azri Hizami
Published: November 2018

In recent years, electric two-wheelers are emerging as one of the alternatives to improve the sustainability of transportation energy and air quality, especially in urban areas. Although electric two-wheeler motorcycles are environmentally friendly, they underperform compared with gasoline two-wheelers in many respects, particularly in speed and cruise distance between refuelling and recharging. Therefore, the engine development program can be done with a dynamometer. Variables such as the shape of torque and power curves can be analyzed. Hence, this project is aimed to develop a chassis dynamometer that can be used to measure mechanical power, speed and torque, and provide a controllable load to the electric motorcycle being tested. The prototype of chassis dynamometer for electric motorcycle had been developed and performance of the chassis dynamometer was tested by using an electric bicycle to emulate the basic performance requirements of an electric motorcycle which consist of maximum speed, driving range and acceleration.
Thermal energy storage (TES) technology for active and passive cooling in buildings: A Review
Authors: Aziz Nursyazwani Abdul , Amin Nasrul Amri Mohd , Majid Mohd Shukry Abd , Zaman Izzudin
Published: November 2018

Thermal energy storage (TES) system is one of the outstanding technologies available contributes for achieving sustainable energy demand. The energy storage system has been proven capable of narrowing down the energy mismatch between energy supply and demand. The thermal energy storage (TES) - buildings integration is expected to minimize the energy demand shortage and also offers for better energy management in building sector. This paper presents a state of art of the active and passive TES technologies integrated in the building sector. The integration method, advantages and disadvantages of both techniques were discussed. The TES for low energy building is inevitably needed. This study prescribes that the integration of TES system for both active and passive cooling techniques are proven to be beneficial towards a better energy management in buildings.
Study on Premature Failure of PV Systems in Malaysia using FMEA and Integrated ISM Approaches
Authors: Han Tan Dei , Razif Mohamad Rosman M. , Sulaiman Shaharin A.
Published: November 2018

Solar photovoltaic (PV) systems has the potential of supplying infinite electricity from renewable energy to rural areas around Malaysia. Various preterm failures happening frequently on the system lead to its drop in efficiency and breakdown. Lack of studies on the system in Malaysia hinders the development in terms of operation and maintenance. There is no proper documentation relevant to the premature failure of the system in Malaysia. The main objective of this project is to study the nature of premature failure of stand-alone solar photovoltaic system in Malaysia in order to improve the operation and maintenance of the system. The present study would provide reference for proper planning on operation and maintenance of the PV system. The study was conducted base on expert’s input and extensive literature survey. FMEA method and ISM approach are applied to analyze the data collected. Poor cooling system have the highest risk priority number. Poor workmanship is the least depending factor for premature failure to happen thus requires most attention. Highest driving force of premature failure is poor monitoring and maintenance. More focus should be given to these premature failure during the planning for operation and maintenance due to its severity and impact.
A Novel High Gain Voltage-Lift Technique Based Transformer free Non-isolated Quadratic Boost Converter
Authors: Padmavathi Pydikalva , Natarajan Sudhakar
Published: November 2018

A novel high gain voltage lift technique based transformer free non isolated boost converter is proposed with single switch operating at constant frequency in this paper. This performance of this converter is very good and high efficient compared to the conventional boost converters. The high gain is obtained by applying voltage lift cell to the quadratic boost converter. The simple structure, easy controlling and lower voltage stress. The operating principle with theoretical analysis and simulation results of proposed converter for various loads at 10 kHz frequency are discussed in this paper to compare the performance of this novel boost converter.
Theoretical Analysis on the Micro Gas Turbine Integrated Solar Farm for Power Output Stabilization
Authors: Basrawi Firdaus , Al-Anati A.I.M. , Ibrahim Thamir K. , Yusof Mohd Hazwan , Razak A.A. , Sulaiman Shaharin Anuar , Yamada Takanobu
Published: November 2018

Solar farm could not penetrate grid at substantial amount because it could disturb the grid operation due to its fluctuation output. This, the objective of this study is to theoretically analyze the power output stabilization of a solar farm by integration of Micro Gas Turbine (MGT). A 1MW scale of solar farm was first designed according to IEC 60364-5-52:2003, MS281837 and AMBO Chart method. Then, designed solar farm and MGT were modelled and simulated Simulink. In this study, both system need to stabilize power output at 800 kW throughout the year. It was found that it is possible to balance the power output of the solar farm to have constant power output throughout the year at 800 kW. However, all MGTs frequently operated at partial load that decreased their efficiency. Thus, it is possible to solve the solar farm problem with the technique, but further investigation the environmental and economic impact in comparison with a conventional power generation and a solar farm only is needed.
Computational analysis of the inflow air slot size influence on solar vortex generator peformance
Authors: Ismaeel Ali A. , Al-Kayiem Hussain H. , Baheta Aklilu T. , Aurybi Mohammed A.
Published: November 2018

Nowadays, attention is directed towards the possibilities of harnessing the potential of tornado by creating an artificial convective vortices for green electricity generation. In view of this research trending, a novel new solar vortex power generator, designed, fabricated and experimented at University Technology PETRONAS, Malaysia. In this paper, ANSYS - FLUENT 15 software was used to simulate the influence of inflow slot size on the vortex updraft velocity. Two cases hav been investigated. Case 1 with new dimension of 0.1 m width and guide vane height of 0.6 m. Whereas, case 2 with slot dimension of 0.3 m height and 0.15 m width. From the attained results, it could be deduced that the slot size is an important parameter which impacts on the vortex strength. The vortex exit velocity increased by 50% a nd by 2.6% for the case 1 and case 2, respectively. This indicates that the slot height is highly influencing the vortex strength. Thus far, the indexes from the numerical simulation can be used in re-designing of the inflow slot size for optimal performance.
Design procedure for dual air handling unit of air-conditioning system
Authors: Aziz Azizuddin Abd , Sumiyoshi Daisuke , Akashi Yasunori
Published: November 2018

The use of conventional air-conditioning system in tropical climate is ineffective to reduce the humidity. In a typical application, the indoor temperature has to be overcooled to decrease the humidity which has an inherent effect of high energy consumption. The introduction of dual air handling unit (AHU) is the answer to high humidity environment. Each AHU is tasked to control the parameter of temperature and humidity respectively according to the desired value. In this paper, the objective is to design the procedure of sizing the dual AHU so that the control system could run efficiently. Basically, eight (8) steps are necessary to size the dual AHU system and the procedure requires sequential manner. Namely, the design process are indoor design condition, fresh air flow, outdoor design condition, room cooling load, capacity of both AHUs, supply air temperature of second AHU, supply air temperature of first AHU and the enthalpy of both AHUs. The design procedure also requires a psychrometric chart to indicate the air thermal condition throughout the cycle of the air-conditioning system. In conclusion, the proposed design procedure is simple yet effective for the application of dual AHU system to handle the excessive latent heat environment.
Analysis of Solar PV Application Based on Bidirectional Inverter
Authors: Maideen Abdhulkader Jeylani A. , Kanakaraj J. , Mahaboob Subahani A. , Rameshkumar K.
Published: November 2018

Building a DC-DC converter with high step-up, low cost and high efficiency from low DC voltage is the requirement in many applications. It is achieved by employing a front end boost converter based full bridge inverter on bidirectional inverter. In conventional boost converter during device turn-off, voltage overshoot occurs across the semiconductor devices. So, an additional snubber or voltage clamping is required to limit the overshot voltage. It upturns the component’s count and losses making the converter less efficient. The above problem can be avoided by operate the converter with soft-switching method by using secondary modulation technique. Hence, it avoids the need of additional snubber or auxiliary circuit. Soft switching operation is proposed in the bidirectional inverter. Soft switching operation is achieved through the auxiliary circuit, which consist of two auxiliary switches, Front end converter and full bridge inverter. Bidirectional inverter allows current flow in both direction and therefore permits energy flow from the grid to storage when solar energy is not available. The theoretical analysis of the proposed converter is verified using simulation results.
Fitting Rainfall Data by Using Cubic Spline Interpolation
Authors: Azizan Irham , Karim Samsul Ariffin Bin Abdul , Suresh Kumar Raju S.
Published: November 2018

This study discusses the application of two cubic spline i.e. natural and not-a-knot end boundary conditions to visualize and predict the rainfall data. The interpolation and the analysis of the rainfall data will be done on a monthly basis by using the MATLAB software. The rainfall data is obtained from Malaysia Meteorology Department for Ipoh and Petaling Jaya in year 2014 and 2015. The interpolating curves are then being compared and if there is any negative value on the interpolating curve on some sub-interval, that part will be replaced by using the Piecewise Cubic Hermite Interpolating Polynomial (PCHIP). We discuss the missing data imputation by using both splines.
Comparative Study on the Performance of S-Shaped Diffuser With Shorten Length
Authors: Jessam Raed A. , Al-Kayiem Hussain H. , Nasif Mohammad S.
Published: November 2018

This study presents numerical investigation on the performance of S-shaped air intake normal and aggressive diffuser with 22% length reduction. Both models have same area ratio of 3.1 with different total length, turning angle and radius of curvature. The numerical investigation was implemented using CFD simulation by ANSYS-FLUENT 15 software. The inlet Reynold number was 4×104 and turbulence intensity 4.1%. The performance evaluation was performed throw evaluation the static pressure coefficient, pressure loss coefficient, distortion coefficient and static pressure wall coefficient. The numerical results show that the performance in the case of aggressive S-shaped diffuser has been reduced compared to the normal S-shaped diffuser. This reduction resulting from the early flow separation and increase of the separation zone due to the high curvature of top and bottom surfaces of aggressive S-shaped diffuser. The results show that the static pressure recovery coefficient decreased by 31%, the total pressure loss coefficient and distortion coefficient increased by 9.5% and 8.2%, respectively, compared to the S-shaped diffuser. The static pressure wall coefficient on the top and bottom surfaces was dropped with the aggressive S-shaped diffuser.
Effect of Blending Ratio on Quality of Producer Gas From Co-Gasification of Wood and Coconut Residual
Authors: Inayat Muddasser , Sulaiman Shaharin A.
Published: November 2018

Biomass gasification often encounters the shortage of biomass supply for continuous operation. Co-gasification of different biomass materials is a promising solution that can address the shortage of biomass supply for the continuous gasification process. However, the effectiveness of co-gasification is not well understood. Furthermore, there is nearly no reported work of co-gasification of two or more biomass materials. In this study, two Malaysian local biomass materials, wood residual and coconut shells were co-gasified in a 33.6 kW thermal capacity downdraft gasifier to investigate the effect of blending ratio the on quality of the producer gas. The results show that producer gas composition increased as coconut shells proportion increased in blends of up to 60%. A blend of 40:60 W/CS results in a synergetic effect as compared to discrete gasification of both feedstock. The maximum H2 and CO were obtained as; 11.46 vol.% and 23.99 vol.% respectively at 40:60 W/CS blending ratio. The results achieved from 40:60 W/CS blend were 16.70% and 10.96% higher as compared to pure wood gasification for H2 and CO respectively. It is concluded that coconut shells can be utilized a substitute of wood residual in form of blends or as discrete feedstock for the continuous gasification process without the change in gasifier geometry.
Design of Flue Gas-Air Heat Exchanger for Regeneration of Desiccant System
Authors: Abdulmalek Shaymaa H. , Al-Kayiem Hussain H. , Baheta Aklilu T. , Gitan Ali A.
Published: November 2018

Heat recovering from biogas waste energy requires robust heat exchanger design. This paper presents the design of fuel gas-air heat exchanger (FGAHE) for recovering waste heat from biogas burning to regenerate desiccant material. Mathematical model was built to design the FGAHE based on logarithmic mean temperature difference (LMTD) and staggered tube bank heat transfer correlations. MATLAB code was developed to solve the algorithm based on overall heat transfer coefficient iteration technique. The effect on tube diameter on design and thermal characteristics of FGAHE is investigated. The results revealed that the smaller tube diameter leads to smaller heat transfer area and tube. On the other hand, the overall heat transfer coefficient and Nusselt numbers have larger rates at smaller tube diameter. In conclusion, the nominated tube diameter for FGAHE is the smaller diameter of 0.0127 m due to the high thermal performance.
Performance Analysis of Transcritical Carbon Dioxide Rankine Cycle with Regenerator
Authors: Baheta Aklilu T. , Hailegiorgis Sintayehu M. , Oumer Ahmed N. , Sulaiman Shaharin Anwar B
Published: November 2018

Transcritical carbon dioxide Rankine cycle (TCRC) has a potential to convert low grade heat source into power. Thus, the objective of this paper is to evaluate TCRC performance based on the first and the second law of thermodynamics for wide and different operating conditions. To address this, TCRC thermal efficiency, exergetic efficiency, utilization ratio and the exergy destruction of the components are analyzed parametrically. Engineering Equation Solver (EES) is used to solve the set of equations and to evaluate the working fluid properties at the given conditions. For the analysis compressor efficiency, turbine efficiency and effectiveness of the regenerator are assumed to be 0.9, 0.9 and 0.95, respectively. The pump inlet pressure was assumed to be 6.2 MPa. It is found that at 10 MPa turbine inlet pressure 240°C is the optimal turbine inlet temperature operating condition. The percentage of exergy destructions at 240°C turbine inlet temperature are 0.94, 4.53, 9.55, 41.23, and 43.74 by the pump, turbine, condenser, heater and regenerator, respectively. Hence, the highest and the smallest exergy destructions are in the regenerator and the pump. This study will help to select the potential component for further improvement.
Modelling flood reservoir integrated with pumped hydropower storage for electricity production using HOMER
Authors: Safi Aishah , Anuar Shahrani , Nafiz Daing Mohd , Basrawi Firdaus , Nazani Mohd , Shukrie Ahmmad
Published: November 2018

This paper presented the potential of flood reservoir integrated with pumped hydropower storage for electricity production in Pekan, Malaysia. Based on the procedure in T echnical Release 55 (T R- 55), the volume of the reservoir to attenuat e flood was 5.2 million3. The volume estimated will be the size of the lower reservoir of proposed PHS and act as flood water catchment during flood seasons. The system proposed an integration of PHS with wind turbines and connect it to the grid. The Hybrid Optimization Model for Electric Renewable (HOMER) software was used to model system for electricity production. The software has simulated 200 different configurations of systems which included the diesel-only system and hybrid wind/diesel system. The standalone diesel system could produce about 25,041,824 kWh of electricity per year and emits 30,030,457 kg/year of pollutants into the atmosphere. Meanwhile, the hybrid wind/diesel could produce 25,668,980 kWh/year of electricity and emits 29,293,174 kg/year of total pollutants into the air. Although, the standalone diesel has the lowest cost of energy among all configurations which is RM 0.852/kWh, but it releases the most amount of carbon dioxide. The high emission of this gasses can have many environmental effect s in a long term.
Effect of Grain Boundary Formation in Microstructural Changes in IN 738 Service Exposed Turbine Blade
Authors: Owolabi Afolabi Lukmon , Megat-Yusoff Puteri Sri Melor , Amir Norlaili , Jasmani M.S. , Syed Ahmad Ghazali S.M.A.
Published: November 2018

Microstructural changes on a Nickel based superalloy service exposed gas turbine blade after 52,000 hours at 720°C temperature was investigated. The study examines the grain boundary growth sizes; the changes with respect to gamma prime (γi) precipitate and phase distributions that occurred during operation. In order to observe the changes some different portions of the turbine blade undergone scanning electron microscope (SEM) to determine the grain size measurement and the EDX was used to evaluate the elemental analysis. The grain growths were discrete in formation along the grain boundary (GB) and little difference in the size of (γi) precipitates existed in different locations. The gradual transition of grain boundary-carbide morphology from the original fine discrete to fine semi-continuous, continuous film-like and finally coarse is observed in the specimens. The changes mostly evolves around two distinct phases which is from the solid to the equilibrium (sigma coarse phase) and then back to the solid (hardening gamma prime precipitate) phase. The grain size of (γi) precipitate varies throughout the surface of the turbine blade and there is a significant difference between the leading and trailing edge. The microstructural changes on the serviced blade can be interpreted to indicate that no obvious microstructural degradation and phase deformation occurred during exposure time.
Synthesis of non-edible biodiesel from crude jatropha oil and used cooking oil
Authors: Sapee Syazwana , Yusop Ahmad Fitri , Jaafar Mohammad Nazri Mohd , Mamat Rizalman , Ibrahim Wan Asma , Farouk Hazir , Rahim Norwazan Abdul , Razak Ilyia Syafira Ab , Malik Muhammad Syahiran Abdul , Bo Zhang
Published: November 2018

This study focuses on a feasibility study of alternative nonedible crude oil such as jatropha and used cooking oil in biodiesel production. Crude jatropha oil (CJO) and used cooking oil (UCO) were converted to biodiesel using a two-step transesterification process with presents of acid-based and alkaline-based catalysts. Each three biodiesel blends (B5, B15 and B25) have been produced by blended with conventional diesel fuel (CDF). Determination of the fuel properties for each blend including CDF, Jatropha Methyl Ester (JME) and Used Cooking Oil Methyl Ester (UCOME) have been carried out. The average yield for jatropha and used cooking oil biodiesels production was 94.3% and 92% respectively. The increment of the percentage of JME or UCOME in its blends is proportional to fuels physical properties such as density, specific gravity, kinematic viscosity and surface tension, however inversely proportional to fuels calorific value. Based on the results of this study, it is acceptable to conclude that non-edible CJO and UCO are viable alternatives to edible oil as feedstock to renewable fuel in order to reduce the greenhouse gases produced.
Effect of limestone catalyst on co-gasification of coconut fronds and wood chips
Authors: Inayat Muddasser , Sulaiman Shaharin A. , Hung Tham W. , Guangul Fiseha M. , Basrawi Firdaus
Published: November 2018

Biomass energy via gasification is an attractive substitute of fossil fuels. The distribution of biomass on the earth is scattered, so transportation and collection of biomass complicates the supply of biomass especially when the gasification rely on one type of biomass. Therefore, cogasification of different biomass is proposed as a potential solution for interruption-free gasification. Beside, unwanted by-products such as tar that cause blockage in downstream equipment can be minimized through the use of catalyst in gasification to accelerate tar reforming process. In this study, catalytic co-gasification of blended feedstock of 70% wood chips and 30% coconut fronds was carried out in a downdraft gasifier using limestone as primary catalyst. The effects of catalyst loading (0%, 30%, 50%, and 70% w/w) on syngas composition, gas yield, carbon conversion efficiency and heating value of syngas were investigated. The results showed that at 50% biomass to catalyst ratio, maximum H2 content of 11.39%, CO of 17.88%, carbon conversion efficiency of 69.49%, gas yield of 1.68 Nm3/kg and higher heating value of syngas 5.11 MJ/Nm3 were achieved. Higher catalyst loading (70%) blocked the air passage, which caused poor gasification. No more than 50% catalyst suggested for stable co-gasification operation.