bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimisation-Based Power Management System for an Electric Vehicle with a Hybrid Energy Storage System
Authors: Gonsrang S. , Kasper R.
Published: September 2020

Hybridisation of energy storage sources is necessary for extending mileage of electric vehicles. However, coordination of multiple devices with different characteristics is challenging. This paper presents a power management system (PMS) for an electric car equipped with a battery pack, supercapacitor bank, and range extender. The proposed PMS deals with vehicular load distribution by solving a power management problem, formulated as a constrained quadratic program (CQP). Then, the optimised variables, such as the desired speed and optimised operation points of the car’s components, are implemented by controllers at a component level. Complete knowledge about the trip is unwanted because the proposed PMS considers a power management problem only over a controlled horizon of one sampling period. Furthermore, this work varies weight factors to tackle various difficulties, for instance, regenerative power management. The simulation results revealed that the proposed system optimally allocated an electric power load to the car components, without violating any physical constraints. Also, the comparative study showed that the performance of the CQP in power management was comparable to that of the benchmark, based on a nonlinear model predictive control.
A Review on Ruben’s Tube as Acoustic Propagator
Authors: Salim R. , Syed Shazali Syed Tarmizi , Hamdan S. , Andrew-Munot M. , Mohtar A. M. A. A. M.
Published: September 2020

In 1905, Ruben’s Tube was invented by German physicists Heinrich Ruben and Otto Krigar-Menzel. The tube is closed at one end and the other end is attached with a loudspeaker, then filled with flammable gas. With the help of the Ruben’s Tube, the standing waves were represented physically by fire. There are no specific standards in which Ruben’s Tube is constructed. At certain resonance frequency, the flame produced visual standing wave that varies in height. It has been used in the teaching of acoustical resonance behaviour. This article provides review on Ruben’s Tube and its operation, as well as some commentaries and drawbacks for each subtopic. Each of the journals that have similar setup have been reviewed to further explain the phenomena.
Dynamic Instability of High-Speed Rotating Shaft with Torsional Effect
Authors: Wahab A. M. A. , Yusof Z. , Rasid Z. A. , Abu A. , Rudin N. F. M. N.
Published: September 2020

Today’s design of machine rotor requires the rotor to operate at a high rotational speed to improve the efficiency of the machine. However, the existence of disturbances such as periodic axial load may cause parametric resonance to the rotor system in addition to the common force resonance. Previous studies on this parametric resonance of shaft typically included the element of translational and rotary inertia, gyroscopic moments and bending and shear deformation but surprisingly neglected the effect of the axial torque. This paper investigated the parametric instability behaviour of the shaft rotating at high speed while considering the torsional effect of the shaft. Based on the finite element method, a shaft model that includes torsional deformation as one of its degree of freedom was established. The Mathieu-Hill equation was derived, and then the Bolotin’s method was used to solve the equation by establishing the parametric instability chart. Two types of the rotary system were studied: a shaft with different boundary conditions and shaft with different bearing types. The results were initially validated with past findings. Following that the results were compared to the results correspond to the Timoshenko’s beam formulation that omits the torsional degree of freedom. The effect of axial torsional deformation was found to be very significant especially at high speed. The developed model in this study shows that at the shaft speed of 40000 rpm, the effect of torsional deformation has given the difference of more than 100% in the frequency ratios correspond to the 4DOF and 5DOF models for the case of fix-free boundary condition.
Water Absorption Behaviour and Mechanical Performance of Pineapple Leaf Fibre Reinforced Polylactic Acid Composites
Authors: Agung E. H. , Hamdan M. H. M. , Parlaungan Siregar Januar , Bachtiar D. , Tezara C. , Jamiluddin J.
Published: September 2020

Fast-growing scientific work is focusing on alternative sources to replace modern synthetic fibre materials due to the adverse effects caused by petroleum-based materials. Natural fibre possesses high potential as a replacement for synthetic fibre and petroleum-based products. These materials are not only greener and environmental-friendly, but also safe for human health. As such, this study investigated the influence of compatibilising agent of maleated anhydride polyethylene (MAPE) on mechanical performance of pineapple leaf fibre (PALF) reinforced polylactic acid (PLA). The raw materials, such as PALF, PLA, and MAPE, were mixed by using a hot roller mixer machine and hot compression moulding at 190ºC. The specimens were then tested for water absorption and flexibility. The specimens were submerged in water for 0, 7, 14, and 21 days. Three types of tests were conducted, namely water absorption, tensile, and flexural assessments. The results of water absorption, tensile, and flexural tests for the untreated PALF composite (UPALF) and treated PLAF composite (TPALF) were recorded and explained. As a conclusion, composite materials based on hydrophilic natural fibre may reduce the tensile and flexural properties of the composite.
Energy Harvesting from Rotating Motion of In-Pipe Robot Cleaning Device
Authors: Zainal Abidin A.S. , Sawing T. B. , Mohamaddan S. , A. Halim H. H. , Annisa J. , Muslimen R. , Ashari M. F. , Jamaludin M. S.
Published: September 2020

In-pipe robot (IPR) needs a continuous and constant power supply for its operation. This research is a continuation from the previous IPR: D200 for cleaning operation. The objective of this research is to study the possibility of harvesting electrical energy from IPR and how much electrical output can be generated from the proposed solution. The concept is to re-use kinetic energy from high speed rotation of the IPR cleaning device to be converted into electrical energy which can be used to recharge the main battery. Two types of circuits have been developed namely unregulated charging circuit and regulated charging circuit. Both developed circuits are simulated using Livewire software. The developed circuits are then validated using experiment to measure the output voltage. Simulation results show that the unregulated charging circuit can produce output voltage of 10.90V while regulated charging circuit produces an output voltage of 5.47V. Experiments have confirmed that unregulated charging is able to produce higher voltage of 6.93V as compared to regulated charging circuit. The experimental results are lower than simulation results due to power loss during power transmission of the actual circuits. In the meantime, the unregulated charging circuit produced inconsistent output compared to the regulated charging circuit. Therefore, the regulated charging circuit will be considered for the IPR: D200 applications as well as other similar applications.
Dynamic Behaviour and Characteristics of Rubber Blade Car Performance
Authors: Mohamad S. M. , Othman N. , Sharif I. , MD. Zain M. Z. , Abu Bakar A. R.
Published: September 2020

High technologies have helped so much in improving an optimizing the engine design and performance of the car. Improved isolation has helped to minimize the engine noise making other automotive part noises become more detectable. One of the noise sources are the wipers. When a wiper operates on a windshield, vibratory phenomena may appear due to flutter instabilities and may generate squeal noise. In order to obtain good wiping behaviour and characteristics, the rubber blade should be in complete contact with the glass and under uniform contact pressure while not generating vibration as it moves over the glass. A good wiping performance can be achieved by a proper design of the wiper structure as well as a good understanding of the mechanical behaviour of the rubber blade. The primary objective of this research is to investigate the dynamic behaviour and characteristics of rubber wiper blade performance in order to reduce the automotive windscreen wiper noise and vibration effects. In order to achieve the objective of this research, two types of wiper is used. One is hybrid type and second is conventional type. Then the behavior of wiper can be investigated. The force resistive sensor is used to measure the force distribution exerted on the windshield for the characteristics wiper noise for specific points. The obtain vibration data is processed by single-board microcontrollers. Behaviour movements of blade produce different vibration that can be investigated the maximum noise occurs on wiper blade operation using Uni-axial accelerometer A MMA7660. As a result, confirmation behaviour is shown the contact force distribution between rubber blade and glass is produce non-uniformly contact force and identical for hybrid type wiper and uniform contact force and not identical for conventional type wiper. In addition, characteristic of wiper rubber blade due to environment condition such as humidity, temperature and wiper stiffness are major factor in this research. As a conclusion, the results for behaviour of wiper blade depends on structural effect of the wiper blade related to the contact force distribution between the rubber blade and the glass. Secondly the characteristics of wiper rubber blade depends environment condition such as humidity and the temperature. The methodology is achievable to discovery the knowledge of dynamic behaviour and characteristics of wiper rubber blade in future.
Performance of Near Dry Hard Machining Through Pressurised Air Water Mixture Spray Impingement Cooling Environment
Authors: Kumar R. , Sahoo A.K. , Mishra P.C. , Das R.K.
Published: September 2020

The present paper emphasizes on experimental investigation, mathematical modelling, optimisation, tool life and cost analysis during machining of AISI D2 (heat treated) (55±1 HRC) steel using uncoated carbide tool through a novel method under spray impingement cooling environment. Taguchi based L16 orthogonal array was utilised to conduct the experiments. Analysis of variance with 95% confidence level shows that the feed and depth of cut, are the most compelling factor towards surface roughness as well as chip reduction coefficient whereas cutting speed is the utmost compelling feature associated to flank wear as well as chip-tool interface temperature. Optimised result is identified as v1-f1-d1 (machining speed of 63 m/min; cutting feed of 0.04 mm/rev and depth of cut of 0.1 mm) based on grey relational analysis and tool life is found to be 15 minutes at optimised cutting conditions. Flank wear due to abrasion, catastrophic failure due to diffusion, chipping and notch wear are noticed as the major tool wear mechanisms in hard turning. Mathematical machinability models show statistically significance because due to the superior coefficient of correlations. As the global machining cost for each part is less, uncoated carbide tools can machine effectively, efficiently and economically at optimum cutting conditions under spray environment.
Effects of Hot Exhaust Gas Recirculation (EGR) on the Emission and Performance of a Single-Cylinder Diesel Engine
Authors: A. A. Mossa M. , Hairuddin A. A. , Nuraini A. A. , Zulkiple J. , M. Tobib H.
Published: September 2020

With the increment in global demand for energy, there is a need to reduce vehicle emission, which is among the major causes of air pollution around the world. In order to reduce the emissions levels, this study focuses on the effects of hot exhaust gas recirculation (EGR) system on the performance and emissions of a direct injection (DI) diesel engine. The performance studied includes engine power, torque, brake mean effective pressure, fuel consumption and the exhaust emission. The engine used in this study was a single-cylinder, four-stroke engine with an air-cooled system at a rated speed of 3600 rpm with displacement of 0.219 litres. The engine was operated at varying speeds of 1600 to 3600 rpm with different percentages of EGR (5%, 7%, 10% and 15%). Based on the results, it was shown that EGR had decreased the engine brake power and torque while increasing fuel consumption at the same time. The engine with EGR has reduced the emission level of NOx from 800 to 240 ppm and CO2, from 9% to 4%, while increasing the CO from 2% to 4% and UHC from 10 to 100 ppm. Hence, it was concluded that low emission level of NOx and CO2 could be obtained using EGR as it can be used to improve the emission level of a homogeneous charge compression ignition (HCCI) even further in the extension of this study.
Computational and Experimental Investigation of using an Extractor in the Vertical Gravitational Flash Tank Separator
Authors: Mahmood R. A. , Buttsworth D. , Malpress R.
Published: September 2020

The vertical gravitational flash tank separator can be used to increase the performance of a refrigeration cycle. Using the vertical gravitational flash tank separator improves the effective area and enhances the heat transfer coefficient inside the evaporator. However, the vertical gravitational flash tank separator still needs further investigation to improve its performance. This paper provides an investigation study to demonstrate the improvement of separation efficiency using an extractor inside the vertical gravitational flash tank separator. Computational Fluid Dynamic (CFD) was used to assess the optimum configuration and dimension of the extractor. A series of experiments were performed to test and confirm the proposed CFD configuration of the extractor design. The results revealed that the extractor had increased the separation efficiency by 2 %.  The CFD simulations gave a good agreement with the experiments; however, all the simulations underestimated the liquid separation efficiency by approximately 0.02 over the range of conditions tested.
Nonlinear Buckling Analysis of Steel Cylindrical Shell with Elliptical Cut-out Subjected to Longitudinal Compressive Load
Authors: Salloomi K. N. , Sabri L. A. , Hamad Y. M. , Al-Sumaidae S.
Published: September 2020

The current paper investigates the effect of cut-out design parameters on load-bearing capacity and buckling behaviour of steel cylindrical shell using a nonlinear finite element analysis in modelling cylinder buckling under longitudinal compressive load. The effect of four geometry design parameters: shell diameter to thickness ratio, cut-out location, orientation, and size were investigated in this study. To enhance the prediction of buckling behaviour, both geometrical and material nonlinearities were considered. An ANSYS APDL code was written and tested by verifying its validity through comparison with former buckling study. The results showed that changing the cut-out location from mid-height of the cylindrical shell towards a fixed edge caused an increase in the buckling load value. Moreover, the study showed that increasing parameters such as shell thickness and cut-out orientation have a positive influence in which the buckling load value increased too. For fast design purposes, an empirical numerical based regression formula was presented for the calculation of the critical buckling load of a cylindrical shell having an elliptical cut-out.
Adjustable Valve Semi-Active Suspension System for Passenger Car
Authors: Ahmed M. R. , Yusoff A. R. , M. Romlay F. R.
Published: September 2020

The suspension of the car plays a very important role in the safety and the comfort of the vehicle and for absorbing the shock waves and give comfort for the driver and passenger. This paper improves the performance of an automobile suspension system by developing electronically adjustable semi-active shock absorber. This achieved by attaching stepper motor for each shock absorber which helps in adjusting the bleed orifice to a certain position that alternates the hydraulic oil flow in the shock absorber between piston’s chamber during the process of compression and rebound. To evaluate the effect of developed semi-active shock absorber on the dynamic behaviour of the vehicle, several tests were carried out on different types of road condition (bumpy, straight-line and roundabout). These tests were used to evaluate the acceleration and ride quality. There is a great range in response when the bleed orifice is opened reached up to 35% between the stiff and soft setting. The value of root means square acceleration (RMS) was calculated and compared with the standard of human exposure to whole-body vibration, which shows an error of 6% slightly. The result shows the effect of electronically controllable shock absorber on a vehicle’s dynamic behaviour — the advantage of electronics to improve the performance of ride comfort and reduced the harms due to undesired vibration.
Numerical Modelling of a Concentrating Photovoltaic Thermal Collector
Authors: Valizadeh M. , Sarhaddi F. , Sobhnamayan F.
Published: September 2020

In this paper, the performance evaluation of a concentrating photovoltaic thermal (CPVT) collector is carried out. By writing energy, balance for the various components of CPVT collector, a set of nonlinear equations is obtained to calculate the temperature of different parts of the system. The electrical parameters of the CPVT collector are calculated by the four-parameter model of current-voltage. The simulation results of the present study are in good accordance with the previous studies data. The results show that with the fluid velocity increase from 0.08 to 0.43 m/s, the electrical efficiency and thermal efficiency increase by 1.05% and 2.2%, respectively. The thermal efficiency is enhanced by 9.4% as the receiver width is increased from 0.06 to 0.2 m. With the increase of diameter pipe from 0.017 to 0.06 m an increase of 2.75% and 3.9% is observed in the thermal and electrical efficiencies, respectively. The thermal efficiency has an ascending/descending trend with the increase of collector length. The increase of fluid inlet temperature from 273.15 to 363.15 K reduces the thermal and electrical efficiencies by 7.3% and 4.05%, respectively. The increase of the incident beam radiation from 300 to 1000 W/m2 enhances the electrical efficiency by 4%, while the thermal efficiency has an ascending/descending trend. The ambient temperature increase causes an increase of 5.1% in thermal efficiency. The effect of receiver width and ambient temperature on electrical efficiency is negligible.
Finite Element Modelling of Laser Stitch Welding Joints for Structural Dynamic Predictions
Authors: Aziz Shah M. A. S. , Yunus M. A. , Abdul Rani M. N. , Mohd Zin M. S. , Wan Iskandar Mirza W. I. I.
Published: September 2020

Laser stitch welding is a joining technique that has been increasingly popular in automotive industries, such as in the manufacturing and assembling of the car’s body-in-white (BiW) due to its advantages over the resistance spot weld, such as low heat application and high strength weld. The dynamic behaviour of a laser stitch welded structure is relatively difficult to predict accurately due to local parameters being induced during the laser welding process, such as heat affected zone (HAZ) and residual stress in the welded structure. This paper presents the idea of modelling the laser stitch weld by investigating different types of element connectors that can be used to represent laser stitch weld, such as rigid body element (RBE2), shell element (CQUAD4), bar element (CBAR) and area contact model (ACM2) format of element connectors. The accuracy of finite element models of laser stitch welded joints is compared in terms of natural frequencies and mode shapes with the experiment counterparts. The dynamic behaviour of the measured structure is obtained by using an impact hammer with free-free boundary conditions. It is found that the accuracy of the finite element models of the laser stitch welded structure highly depends on the involvement of residual stress and the heat affected zones that are generated from the welding process.
Effects of Geometry, Triggering and Foam-Filling on Crashworthiness Behaviour of a Cylindrical Composite Crash Box
Authors: Jahani M. , Beheshti H. , Heidari-Rarani M.
Published: September 2020

Crash boxes play an important role in different industries as energy absorbers to reduce damage of accidents. An ideal crash box has lower maximum force and higher energy absorption. The aim of this study is to investigate the effect of various parameters such as geometry (diameter and thickness), triggering and filling with polymeric foam on axial crash behaviour of a composite cylindrical cash box. To this end, a composite crash box is modelled in a commercial finite element software, Abaqus, utilising the Hashin failure criterion to predict damage initiation. Linking damage initiation with material degradation rules provides the capability for damage evolution prediction on the basis of fracture energy of different failure modes. A new parameter (β) is defined to study the performance of a crash box with different geometries, triggers and foam-filling. The results show that three different triggering geometries (chamfer, fillet, and tulip) decrease the maximum load about 7-33%, and improved energy absorption about 40-86% compared to the crash box without trigger. Filling a triggered crash box with polymeric foam also improves energy absorption about 20%. Applying both triggering and foam-filling simultaneously on a crash box has a complementary role to receive a better performance.
Effect Surface Roughness on Fatigue Crack Propagation Behaviour of Fibre Metal Laminates (FMLs)
Authors: Purnowidodo A. , Sofyan Arief S. , Hilmi Iman F.
Published: September 2020

In the present study, the effect of surface roughness of the metal lamina at the interface of fibre metal laminates (FMLs) on the crack propagation behaviours was investigated for different fibre orientation. The FMLs was made by combining the aluminium and the carbon fibre-epoxy composite lamina. The increasing of the aluminium surface roughness at the interface causes the tensile strength to increase for every fibre orientation. The highest tensile strength is 282 and 367 MPa., respectively for fibre orientation 0°/90° and -45°/45° when the surface roughness is 2.89 mm. The increasing surface roughness causes the development of the delamination taking place at the interface is more difficult, and it leads to the shear strength at the interface to increase. Because of this, the tensile strength increases. However, the lifetime is not only influenced by the interface shear strength but also the stress concentration just in front of the crack tip as well as the surface roughness itself leading to the crack to be initiated from the rougher surface. The longest fatigue life is 180 000 cycles in the case of the fibre orientation 0°/90° with the surface roughness of 1.78 mm, and in the case of fibre orientation of -45°/+45° the longest fatigue life is 420 000 cycles when the surface roughness is 0.33 mm. The results of the study show that the surface roughness affects the tensile strength and crack propagation behaviour.
Performance, Emission and Combustion Characteristics of VCR CRDI Diesel Engine Fuelled with n-butanol Blends
Authors: Tamilselvan P. , Gangeya Srinivasu G.
Published: September 2020

This research work indicates the analysis conducted to investigate the performance, exhaust emission and combustion characteristics of a VCR diesel engine fuelled with nbutanol blends at a rated speed of 1500 rpm with 300 bar injection pressure at compression ratios of 16, 18 and 20. The test fuel was prepared by adding n-butanol 10% (NB10) and 20% (NB20) to diesel by volume. The combustion characteristics investigated were; rise in-cylinder pressures, net heat release rate, cumulative heat release rate and mass fraction of fuel burned at all loads using three compression ratios. The emission and performance study also conducted. The higher heat release rates, increased cylinder pressures were observed for both the blends compared to diesel. Increased brake thermal efficiency observed at higher compression ratio for NB20 blend. It had also been observed that the emissions of CO2, HC and NOx were increased for both the blends, while CO emissions decreased in trend with an increase in compression ratio and blend strength.
Straight Path Handling Anomalies of Passenger Cars Induced by Suspension Component and Assembly Tolerances
Authors: De Rosa M. , De Felice A. , Grosso P. , Sorrentino S.
Published: September 2020

The effects on handling due to suspension component and assembly tolerances are analysed focusing on three anomalies affecting passenger cars travelling on straight paths, namely ‘pull to side’, ‘steering wheel misalignment’ and ‘drift leeward’. These anomalies do not constitute safety problems but represent a cost factor in the automotive industry since they occur in small but not negligible percentage of the overall car production. The present contribution is therefore focused on understanding which are their causes, and on reducing their extent, in the specific case of vehicles with front Double wishbone suspension and rear Five arms suspension. To this purpose, the vehicle assembly process is analysed in terms of errors and tolerances for identify the most influential parameters on handling irregularities. Sensitivity analysis by multibody virtual modelling, and subsequent correlation with experimental data from pre-setting and wheel aligner benches, have provide sufficient information for setting tolerance thresholds, able to keep the handling anomalies under study within acceptable bounds. As a result, ‘pull to side’ and ‘steering wheel misalignment’ has been found to be mainly related to the set up phase of wheel angles (front camber angles influencing pull to side, front and rear toe angles influencing steering wheel misalignment), while the main cause of ‘drift leeward’ has been identified with (rear) ride steer. Application of the procedure to a production line led to a consistent reduction (from 3% down to about 1% of the overall production) of anomalous vehicles.
Rotordynamics analysis of a single helical gear transmission system for high speed applications
Authors: Ullah Najeeb , Xi C. , Cong T. , Yucheng H.
Published: September 2020

Since the non-linear dynamic response under various high-speed conditions can directly affect the life of gear transmission systems. In addition, the transmission error and dynamic mesh force play a key role in noise and harshness analysis of gear bearing coupled systems. So, in this piece of work, a 12 degree of freedom dynamic model is developed to probe the vibration response by using finite element method and taking into account the bearing and flexible shafts in the first part. Subsequently, some meshing gear characteristics such as dynamic and vibration acceleration response under different rotational speeds (1000-9000 rev/minute) were analyzed whereas critical speed appeared at 6500 rev/minute. Then, the stability analysis is performed to investigate the dynamics behind the critical speed by using MASTA. It was observed that natural frequency of 0.45 kHz for a fourth harmonic order is analogous to critical speed which further causes sudden elevation in both dynamic mesh force and transmission error.
Investigation of the natural ventilation of wind catchers with different geometries in arid region houses
Authors: Sakhri Nasreddine , Menni Younes , Ameur Houari , Chamkha Ali J. , Kaid Noureddine , Bensafi Mohammed , Lorenzini Giulio , Makinde Oluwole Daniel
Published: September 2020

The wind catcher or wind tower is a natural ventilation technique that has been employed in the Middle East region and still until nowadays. The present paper aims to study the effect of the one-sided position of a wind catcher device against the ventilated space or building geometry and its natural ventilation performance. Four models based on the traditional design of a one-sided wind catcher are studied and compared. The study is achieved under the climatic conditions of the South-west of Algeria (arid region). The obtained results showed that the front and Takhtabush’s models were able to create the maximum pressure difference (ΔP) between the windward and leeward of the tower-house system. Internal airflow velocities increased with the increase of wind speed in all studied models. For example, at Vwind = 2 m/s, the internal flow velocities were 1.7, 1.8, 1.3, and 2.5 m/s for model 1, 2, 3, and 4, respectively. However, at Vwind = 6 m/s, the internal flow velocities were 5.6, 5.5, 2.5, and 7 m/s for model 1, 2, 3, and 4, respectively. The higher internal airflow velocities are given by Takhtabush, traditional, front and middle tower models, respectively, with a reduction rate between the tower outlet and occupied space by 72, 42, 36, and 33% for the middle tower, Takhtabush, traditional tower, and the front model tower, respectively. This reduction is due to the due to internal flow resistance. The third part of the study investigates the effect of window (exist opening) position on the opposite wall. The upper, middle and lower window positions are studied and compared. The air stagnation or recirculation zone inside the ventilated space reduced from 55% with the lower window to 46% for the middle window and reached 35% for the upper window position. The Front and Takhtabush models for the one-sided wind catcher with an upper window position are highly recommended for the wind-driven natural ventilation in residential houses that are located in arid regions.
Factorial design approach to investigate the significance of factors on the fire resistant, compression and adhesion properties of geopolymer binder
Authors: Mohd Salahuddin M.B. , Mazlan N. , Mustapha F. , Ishak M.R. , Saprudin A.A.
Published: September 2020

Despite numerous studies on the factors which influenced the properties of the geopolymer binder have been conducted, the effect of different factors on the properties of geopolymer binder was not well determined. In this research, geopolymer materials were analyzed and profiled using a statistical approach called 2-level fractional factorial design (2-FrFD). The objective is to screen and identify important factors affecting the behaviour of geopolymer binder. MINITAB, a statistical software, was used to design the experiment, analyze data obtained and present the significance value of the factors via chart and plots. The result showed that the curing temperature (V3) did not have a significant effect on the fire resistant properties of the geopolymer binder with the p-value of 0.526. Other factors and interaction were significant with RHA/AA ratio (V2) was the most significant factor with the coefficient value of 135. For the compression strength properties, all factor and interactions were significant (p-value between 0.000 and 0.009) with the RHA/AA ratio (V2) recorded the highly significant factor with the coefficient value of 8.838. For adhesion strength properties, NaOH concentration (V4) and curing time (V5) were found to be insignificant with the p-value of 0.223 and 0.133, respectively. Other factors and interaction were significant curing temperature (V3) was the most significant factor with the coefficient value of 0.287. This result may hugely benefit future researchers, towards producing halal and sustainable polymer, in determining the suitable factors which have a significant effect of the properties (outcome) of the geopolymer binder.
Characterization of deformation behaviour and fracture mode of recycled aluminium alloys (AA6061) subjected to high-velocity impact
Authors: Ho Choon Sin , Mohd Nor Mohd Khir
Published: September 2020

Recycling aluminium alloys have been shown to provide great environmental and economic benefits. The global demands placed upon recycled aluminium and its product has further increased the need for better understanding and prediction of the deformation behaviour of such materials subjected to various dynamic loading conditions. It is also a topic of high interest for both the designer and the user of metal structures, specifically in the automotive industry. Even though numerous efforts have been made to improve recycling processes of aluminium alloys, very little attention is given on the fracture behaviour related damage and anisotropy during impact. In this study, therefore, the anisotropic-damage behaviour of the recycled aluminium alloys (AA6061) is examined via Taylor Cylinder Impact test. A gas gun was used to fire the projectiles towards a target at impact velocity ranging from 170m/s to 370 m/s. The deformation behaviour, including the fracture modes, digitized footprint and side profile of the deformed specimens, are observed and analysed. Scanning Electron Microscope (SEM) is further used to observe the damage behaviour, including microstructural changes of the impact surface. The damage progression is also analysed by observing the microstructural behaviour of location 0.5 cm from the impact area. General speaking, there are three different types of ductile fracture modes (mushrooming, tensile splitting and petalling) can be observed in this study within the impact velocity range of 170m/s to 370m/s. The critical impact velocity is defined at 212 m/s. The digitized footprint analysis exhibited a non-symmetrical (ellipse-shaped) footprint where the footprints showed plastic anisotropic behaviour and localized plastic strain in such recycled material. The damage evolution of the material is increasing with the increase in impact velocity.
Nonlinear dynamics of a shell encapsulated microbubble near solid boundary in an ultrasonic field
Authors: Ali N.M. , Dzaharudin F. , Alias E.A.
Published: September 2020

Microbubbles have the potential to be used for diagnostic imaging and therapeutic delivery. However, the transition from microbubbles currently being used as ultrasound contrast agents to achieve its’ potentials in the biomedical field requires more in depth understanding. Of particular importance is the influence of microbubble encapsulation of a microbubble near a vessel wall on the dynamical behaviour as it stabilizes the bubble. However, many bubble studies do not consider shell encapsulation in their studies. In this work, the dynamics of an encapsulated microbubble near a boundary was studied by numerically solving the governing equations for microbubble oscillation. In order to elucidate the effects of a boundary to the non-linear microbubble oscillation the separation distances between microbubble will be varied along with the acoustic driving. The complex nonlinear vibration response was studied in terms of bifurcation diagrams and the maximum radial expansion. It was found that the increase in distance between the boundary and the encapsulated bubble will increase the oscillation amplitude. When the value of pressure amplitude increased the single bubble is more likely to exhibit the chaotic behaviour and maximum radius also increase as the inter wall-bubble distance is gradually increased. While, with higher driving frequency the maximum radial expansion decreases and suppress the chaotic behaviour.
The Effect of Profitability, Leverage, and Size on Environmental Disclosure with the Proportion of Independent Commissioners as Moderating
Authors: Ardi Jalu Wicaksono
Published: September 2020

The purpose of this study is to evaluate the effect of profitability, leverage, and company size on environmental disclosure with the proportion of independent directors as moderator. A maximum of 61 agricultural and mining sector companies listed on the Indonesia Stock Exchange in 2014-2018 was the population of this report. The sampling method used purposing sampling, so with 45 units of analysis, we get 9 sample companies. The quantitative method used regression analysis for balance. The results show that profitability does not influence on environmental disclosure. Leverage has a negative effect on environmental disclosure. Company size has a positive effect on environmental disclosure. The proportion of independent directors is able to moderate the effect of profitability on environmental disclosure but is not able to moderate the effect of leverage and company size on environmental disclosure. This study concludes that leverage has a negative relationship with environmental disclosure and firm size has a positive relationship with environmental disclosure and the proportion of independent commissioners moderates the relationship between profitability and environmental disclosure. The findings show the important role of independent commissioners in environmental disclosure, namely providing investors with a balance and maintaining an unbiased and impartial atmosphere.
Identification of Split-GAL4 Drivers and Enhancers That Allow Regional Cell Type Manipulations of the Drosophila melanogaster Intestine
Authors: Ariyapala Ishara S , Holsopple Jessica M , Popodi Ellen M , Hartwick Dalton G , Kahsai Lily , Cook Kevin R , Sokol Nicholas S
Published: September 2020

The Drosophila adult midgut is a model epithelial tissue composed of a few major cell types with distinct regional identities. One of the limitations to its analysis is the lack of tools to manipulate gene expression based on these regional identities. To overcome this obstacle, we applied the intersectional split-GAL4 system to the adult midgut and report 653 driver combinations that label cells by region and cell type. We first identified 424 split-GAL4 drivers with midgut expression from ∼7300 drivers screened, and then evaluated the expression patterns of each of these 424 when paired with three reference drivers that report activity specifically in progenitor cells, enteroendocrine cells, or enterocytes. We also evaluated a subset of the drivers expressed in progenitor cells for expression in enteroblasts using another reference driver. We show that driver combinations can define novel cell populations by identifying a driver that marks a distinct subset of enteroendocrine cells expressing genes usually associated with progenitor cells. The regional cell type patterns associated with the entire set of driver combinations are documented in a freely available website, providing information for the design of thousands of additional driver combinations to experimentally manipulate small subsets of intestinal cells. In addition, we show that intestinal enhancers identified with the split-GAL4 system can confer equivalent expression patterns on other transgenic reporters. Altogether, the resource reported here will enable more precisely targeted gene expression for studying intestinal processes, epithelial cell functions, and diseases affecting self-renewing tissues.
PEMBERDAYAAN GELANDANGAN DAN PENGEMIS MELALUI BIMBINGAN VOKASI DI BALAI REHABILITASI UNIT BINA KARYA YOGYAKARTA
Authors: PUTRI NOVIE PURNIA , ZAHRO’ MUNIFATUZ
Published: September 2020

Abstract. Bum and beggars are one of the social welfare problems in Yogyakata. In the rehabilitation program for sprawl, the Bina Karya unit has a one-year program target for fifty fostered residents with an on-off system, where there is a certain period of sprawl getting fostered until the termination stage. This research discusses the empowerment of homeless people and beggars through vocational guidance at the Center of Rehabilitation of Unit Bina Karya in Yogyakarta. This type of research uses a qualitative approach. The results of this study indicate that the vocational guidance provided by Balai for flat housing includes welding, wood, sewing, and agriculture vocational guidance. In the implementation of vocational guidance has supporting and inhibiting factors. The supporting factors such as cooperation with Balai practitioners who are competent in their fields and collaborating with business units. Then the inhibiting factors include the mental and mindset of the Social Fostered Citizens (WBS) are weak, WBS rejection of guidance, lack of social workers, and vocational assessment is less in-depth. Abstrak. “Gepeng” adalah satu dari sekian masalah sosial yang ada di Yogyakarta. Dalam program rehabilitasi terhadap Gepeng, unit Bina Karya memiliki sasaran program satu tahun untuk lima puluh warga binaan dengan sistem on-off, di mana terdapat periode tertentu terhadap Gepeng untuk mendapatkan binaan sampai pada tahap terminasi. Melalui metode kualitatif, penelitian ini membahas pemberdayaan gelandangan dan pengemis melalui bimbingan vokasi di Balai Rehabilitasi Unit Bina Karya Yogyakarta. Hasilnya menunjukkan bimbingan vokasi oleh Balai terhadap gepeng meliputi bimbingan vokasi las, kayu, menjahit, dan pertanian. Dalam pelaksanaan bimbingan vokasi ada beberapa faktor pendukung dan penghambat. Faktor pendukung meliputi kerjasama Balai dengan praktisi yang kompeten dalam bidangnya dan bekerja sama dengan unit usaha. Sedangkan faktor penghambat meliputi mental dan mindset Warga Binaan Sosial (WBS) yang lemah, penolakan WBS terhadap bimbingan, kurangnya tenaga pekerja sosial, dan assessment vokasional kurang mendalam.
ANALISIS DAMPAK COVID-19 TERHADAP SOSIAL EKONOMI PEDAGANG DI PASAR KLATEN DAN WONOGIRI
Authors: AZIMAH RIZKI NOR , KHASANAH ISMI NUR , PRATAMA RIZKY , AZIZAH ZULFANISSA , FEBRIANTORO WAHYU , PURNOMO SHAFA RIFDA SYAFIRA
Published: September 2020

Abstract. Corona virus (Covid-19) is a new virus that spread in 2020, this virus is a new type of virus (SARS-CoV-2) whose disease is called Coronavirus Disease 2019 (COVID-19). The spread of this virus that is rapidly resulted in social and economic problems occurring almost all over the world, one of them is Indonesia. In Indonesia, almost all areas affected by social and economic change, such as in Klaten Regency and Wonogiri Regency. The aim of this research is to find how the impact of Covid – 19 on social and economic conditions in Klaten and Wonogiri areas. In this study used quantitative method in data retrieval is by spreading questionnaire in 3 market in Klaten and Wonogiri. Data processing of the questionnaire propagation is processed by a descriptive statistical method which then the questionnaire results are processed into data in the form of graphs and explanations. The results showed that with the Covid viral pandemic – 19 This economy experienced a decline especially on market traders who experienced a decrease in turnover and revenue of 50%. Abstrak. Virus Corona (Covid-19) merupakan virus baru yang merebak pada tahun 2020, virus ini merupakan virus jenis baru (SARS-CoV-2) penyakitnya disebut Coronavirus disease 2019 (COVID-19). Penyebaran virus ini yang begitu cepat mengakibatkan terjadinya masalah sosial dan ekonomi yang terjadi hampir di seluruh dunia termasuk Indonesia. Di Indonesia hampir seluruh wilayah terdampak pada perubahan sosial dan ekonominya, seperti pada Kabupaten Klaten dan Kabupaten Wonogiri. Penelitian ini dilakukan dengan tujuan untuk mengetahui bagaimana dampak Covid-19 terhadap kondisi sosial dan ekonomi pada wilayah Klaten dan Wonogiri. Pada penelitian ini digunakan metode kuantitatif dalam pengambilan data yaitu dengan menyebar kuisioner pada 3 pasar yang ada di Klaten dan Wonogiri. Pengolahan data dari hasil penyebaran kuisioner diolah dengan metode statistik deskriptif yang kemudian hasil kuisioner diolah menjadi data berupa grafik dan penjelasan. Hasil yang diperoleh menunjukkan bahwa dengan adanya pandemi virus Covid-19 ini perekonomian mengalami penurunan terutama pada pedagang pasar yang mengalami penurunan omzet dan penghasilan sebesar 50%.
Probability of Paying Zakat from Micro financing Project Returns
Authors: Duasa Jarita , Zainal Nur Hidayah
Published: September 2020

The study aims to investigate the probability of paying zakat among participants or recipients of micro-finance scheme of Amanah Ikhtiar Malaysia. A survey is conducted on participants of Amanah Ikhtiar Malaysia scheme using convenience sampling in Perak and Kelantan. Data from the survey are analyzed using descriptive statistics and logistic regression. The results show that higher probability of paying zakat among respondents determined by small household size, lower per capita income, higher education level and those living in Perak. Thus, efforts should be taken by zakat institutions to well develop good and efficient methods of zakat collection among the participants specifically among low educated and higher income/return of the projects.JEL Classification: C31, C83, D64, I39, G23How to Cite:Duasa, J., & Zainal, N. H. (2020). Probability of Paying Zakat from Micro Financing Project Return. Etikonomi: Jurnal Ekonomi, 19(2), xx – xx. https://doi.org/10.15408/etk.v19i2.15113.
How Efficient are Islamic Banks in Indonesia, Saudi Arabia, and the United Kingdom?
Authors: Suhail Suhail , Nurzaman Mohamad Soleh
Published: September 2020

This research aims to analyze the efficiency level of 13 Islamic Banks in Indonesia, Saudi Arabia, and the United Kingdom from 2015 to 2019. The calculation of the efficiency level in this study is relative, not absolute. This study uses the Data Envelopment Analysis (DEA) method and source data from Bankscope and Bank Focus. This research consists of 3 input variables that are Total of Assets (X1), Staff Expenses (X2) and Total Deposit (X3), and 2 Output that is Income (Y1) and Loan (Y2). This research finds that the overall efficiency level of 13 Islamic banks in Indonesia, Saudi Arabia, and the United Kingdom are fluctuating. According to the result, the Islamic banks in Saudi Arabia is more efficient than in Indonesia and the United Kingdom. There are some inefficient variables—the solution for this inefficiency problem achieve by employing managerial simulation generated by DEA. This study implies that Islamic banks should reduce wasteful variables and optimize the variables that improve the efficiency.JEL Classification: C1, F30, G20, G21How to Cite:Suhail., & Nurzaman, M. S. (2020). How Efficient are Islamic Banks in Indonesia, Saudi Arabia, and the United Kingdom?. Etikonomi: Jurnal Ekonomi, 19(2), xx – xx. https://doi.org/10.15408/etk.v19i2.15862.
Opportunities and Challenges in Developing Islamic Pension Funds in Indonesia
Authors: Kasri Rahmatina Awaliyah , Haidlir Banu Muhammad , Prasetyo Muhammad Budi , Aswin Tika Arundina , Rosmanita Fenny
Published: September 2020

Despite the rapid development of the Islamic financial sector in Indonesia, the development of Islamic pension funds is way behind those of the other Islamic financial sectors. This study aims to explore the opportunities and challenges faced by Indonesian Islamic pension funds. Utilizing a qualitative research method, the study conducted Focus Group Discussions with 23 large pension funds spread across five big cities in Indonesia. It was revealed that opportunities and prospects for developing Islamic pension funds in Indonesia are relatively good. However, various internal and external challenges were found, such as a lack of knowledge; the weak commitment of founders; lack of quality human resources; relatively unfavorable tax treatment; limited investment instruments; competition with government pension schemes; and public literacy problems.  Therefore, two broad strategies are recommended to develop the Islamic funds, namely the provision of direct/indirect incentives to market players, and literacy programmes to targeted/priority groups. These strategies are expected to encourage and accelerate the growth of Indonesia's Islamic pension fund industry in the future.JEL Classification: H55, H75, J32How to Cite:Kasri, R. A., Haidlir, B. H., Prasetyo, M. B., Aswin, T. A., Rosmanita, F. (2020). Probability of Paying Zakat from Micro Financing Project Return. Etikonomi: Jurnal Ekonomi, 19(2), xx – xx. https://doi.org/10.15408/etk.v19i2.16284.