bluuebunny/crossref_metadata_2025 huggingface dataset:
Compaction of a two-dimensional system of composite spherical particles under the influence of self-gravitation: Between lock-and-key model and Tetris-structure
Authors: Viridi S , Dermawan B
Published: June 2020

A self-gravity ofspherical granular particles in the two-dimensional system is simulated. Some of the spherical particles are bonded through a spring force to form composite particles. These spherical and composite particles are attracted to each other due to gravitational force and prevented from collapse into a single point by the normal force. A previous study reported that a two-dimensional monodispersed system will form a hexagonal close-packed (HCP) configuration. In this work, it will be perturbed by some of the composite particles that could have HCP form, simple cubic (SC) form, or a mix of SC-HCP (MSH) form. These forms can be categorized into SC family (□, I, L, T, F, H, E), HCP family (Δ, □, V, X), and MSH family (⌂, K, M, W, N, Z), that can be compacted to maximum contactopy through lock-and-key mechanism (KL). The compaction of some forms from the SC family is similar to the Tetris game, where the structure should be compacted before it could be eliminated in the game. In this work, not all forms from the three families are simulated. The particles in general tend to form a final configuration with the most compact form and the composite particles seems also to influence their surrounding particles to construct the configuration.
Application of Mahalanobis-Taguchi System on Electrical & Electronic Industry
Authors: Nik Mohd Kamil N.N. , Abu M.Y. , Zamrud N.F. , Mohd Safeiee F.L. , Oktaviandri Muchamad
Published: June 2020

Most of Malaysia’s activities in Electrical & Electronic (E&E) Industry more focused in manufacturing industry. The E&E Industry is one of Malaysia’s leading industries that has 24.5 percent in manufacturing sector production. With a rapid expansion of E&E Industry with a continuous innovation, there is no methodological that show the optimization procedure for a process that concern on E&E product in production area. The aim of this work is to develop the optimization parameter for a process of E&E product based on Mahalanobis-Taguchi System (MTS). In methodology, the optimization parameter will develop by using four stages which are construction Mahalanobis Space (MS), validation of Mahalanobis Space (MS), identify the useful characteristic, and predict and future diagnosis. The production in the industry can reduce the rejected product in parameter in a process. Consequently, significant parameters can be identified for E&E product.
Improving productivity through value stream mapping (VSM): A case study at electrical & electronic company
Authors: Rose A.N.M. , Mohamed N. M. Z. N. , Ab Rashid M, F. F. , Noor H. M. , Mohd A.
Published: June 2020

This paper is aim to increase productivity of a case study’s company by eliminating of all possible non value added activities. The study is carried out at a speaker unit of ABC’s company, Malaysia. The current value stream map of production line was developed based on interviews, observations and other data of the company. Then, the future VSM was mapped based on the lean manufacturing principles. The current VSM was identified 12 NVA activities and the improved VSM managed to eliminate all 10 NVA activities. The elimination of NVAs was successfully achieved by applying selected lean tools and techniques. All hidden and cause of wastes were identified and eliminated. As a result the application of VSM has improved company performance by increasing the productivity by 35% and production lead time up to 400%.
Enhancement of Stability and Thermal Conductivity of Nanofluids Using Chinese Ink As a Surfactant
Authors: Mamat H. , Md Isa R.
Published: June 2020

Stability of nanofluids is a basic requirement for cooling application since it is directly related to properties of nanofluids. The objective of the present study is to compare different types of nanoparticles in water based fluids. Nanosilica, graphene and functionalize multi-walled carbon nanotubes (F-MWCNT) were dispersed in water based fluids, and chinese ink was used as a surfactant. Ultrasonication via two-step method was used to produce the nanofluids. The chinese ink have been used to reduce surface tension in fluid and minimize the sedimentation problems of nanofluids. Thermal conductivity of the nanofluids was measured by thermal property analyser. The stability of nanofluids was observed through visual observation and zeta potential measurement methods. F-MWCNT with chinese ink exhibit 79% thermal conductivity enhancement compared to the based fluid. Graphene and F-MWCNT possess zeta potential value which are more than 47 mV (negative) compared to the other tested samples. In conclusion, F-MWCNT nanofluid has a potential to be used in cooling application due to the highest thermal conductivity and nanoparticle stability.
Covalent functionalization of reduced graphene oxide using azido-terminated poly(2-isopropyl-2-oxazoline)
Authors: Abdullah Nabihah , Ifraan Muhd Dzul , Mat Yahya Nor Aisyah , Hashim Norazlina , Abdullah Suhaila , Mohamed Rabiatul Manisah , Kubo Masataka
Published: June 2020

Azido-Terminated Poly(2-isopropyl-2-oxazoline)(N3-PIPOZ) was prepared and it was then functionalized onto reduced graphene oxide (rGO). rGO was prepared from the reduction of graphene oxide (GO) by using hydrazine. The exfoliation of GO was measured using UV-Vis Spectroscopy. As a result, covalent functionalized reduced graphene (rGO-PIPOZ) with good solubility was successfully produced using grafting-on technique. Fourier transform infrared (FTIR) and thermogavimetric analysis(TGA) results proved the attachment of PIPOZ macromolecules onto rGO. rGO-PIPOZ showed best solubility in methanol (MeOH). The production of rGO- PIPOZ can be facilitated to a broad range application of graphene such as in polymer nanocomposites and lithium ion batteries.
Adsorption of Heavy Metals on Banana Peel Bioadsorbent
Authors: Mohamed Rabiatul Manisah , Hashim Norazlina , Abdullah Suhaila , Abdullah Nabihah , Mohamed Amri , Asshaary Daud Mohd Abu , Aidil Muzakkar Kaha Fakrul
Published: June 2020

Heavy metals have become a serious pollutant in water as a result of its non-biodegradable and toxicity properties. In this research, banana peel was synthesized as bioadsorbent to remove heavy metals from contaminated water. The major problem associated with banana peel bioadsorbent is that the activated carbon produces from biomass materials possess insignificant adsorption capability compared to its commercial counterpart. Besides that, large quantity of banana peel wastes contributes to its significant disposal problem. Thus, the present work is expected to solve the problems of banana peel disposal by converting it into bioadsorbent. The objectives of this research are to synthesize banana peel bioadsorbent and to evaluate heavy metals adsorption performance of the banana peel bioadsorbent. The bioadsorbent were treated using KOH in its preparation. The materials then undergo characterization using FTIR and AAS. The carboxylic and hydroxyl functional groups were confirmed by FTIR. The maximum removal efficiency for Pb and Fe ions were 100% and 64% respectively. The comprehensive utilization of low-cost raw material as bioadsorbent in wastewater activities are highly suggested due to its facile processing, abundantly available and environmental friendly.
Extraction of Polyhydroxyakanoate (PHA) from Palm Oil Mill Effluent (POME) using Chemical Solvent Extraction
Authors: Shakirah H.L. , Zulilah Z.N.A. , Aniyyah M.S.N. , Nabihah A. , Radhiah G.S.
Published: June 2020

Palm oil mill effluent or POME is the waste water discharge from palm oil milling activities. Polyhydroxyalkanoate or PHA is the linear polyester that produces by bacterial fermentation of sugar or lipids with nature process. The objectives of this research are to extract PHA from POME using chemical solvent and to study the percentage of purity and recovery of PHA. A methodology was developed for PHA extraction from palm oil mill effluent using chemical solvent. PHA from POME can be extracted by using chemical extraction method by using non halogenated solvent that are acetone, methyl isobutyl ketone and ethyl acetate. The result show percentage of mass PHA recovery with acetone has high percentage that is 93% follow by ethyl acetate with 81.2% and lastly with methyl isobutyl ketone with 66%. Meanwhile, the PHA purity percentage by using acetone is 71%, follow by ethyl acetate 58% of purity obtain lastly methyl isobutyl ketone with 49% PHA purity obtain. PHA can be extracted from POME using chemical solvent extraction method.
Characterization of Solid Polymer Electrolyte Membrane made of Methylcellulose and Ammonium Nitrate
Authors: Abdullah S. , Ahmad A.S , Latif K.S.A , Sobri N.A.M , Abdullah N. , Hashim N. , Yahya N.M , Mohamed R.M
Published: June 2020

Nowadays, the application of portable electronics devices such as smartphone, notebook and tablet playing important role in daily life. This portable electronic devices required portable powering sources such as battery. However, the current battery technology containing liquid electrolyte which is hazardous and harmful when leaking. Therefore, the major purpose of this study was to propose a new biodegradable, safe and low cost solid polymer electrolyte (SPEs) mainly from Methylcellulose (MC) doped Ammonium Nitrate (AN). The study was conducted by using casting method as it is the most appropriate technique due to its simplicity and low cost. Methylcellulose (MC) as the host was doped with different weight percentage (wt%)of Ammonium Nitrate (AN) to fabricate SPEs. The result shows the adding of AN onto MC was significantly enhanced the physical properties of SPEs. The loading of 2g MC with 25% AN (MC2_25AN) yield the highest conductivity at 3.5 × 10−7 Sm−1 at room temperature. Furthermore, the MC2_25AN poses a good stability with the lowest swelling rate. Therefore, the use of low cost and biodegradable MC and AN have a great potential to replace the hazardous electrolyte in electrochemical powering sources.
Soft-Sensing Estimation of Optical Density for PHA Production Using Multilayer Perceptron Neural Network
Authors: Mamat Nor Hana , Mohd Noor Samsul Bahari , Che Soh Azura , Saleena Taip Farah , Rashid Ahmad Hazri Ab. , Jufika Ahmad Nur Liyana , Yusof Ishak Mohd , Mohamad Adida Zuraida
Published: June 2020

Biomass concentration is an important indicator of production rate in polyhydroxyalkanoates (PHA) fermentation process. In current practice, measurement of biomass concentration is done off-line by laboratory analysis that is unsuitable for online process monitoring and control. Soft-sensor is often used as an alternative that provides an estimate of hard to measure parameters from easy to measure process data. However, most of these studies use simulated data or data generated from mathematical model that was developed without full consideration of process and measurement uncertainty. In this study, a soft-sensor is developed from real production data for PHA fermentation in pilot-scale bioreactor with the appropriate data pre-processing techniques applied to process data that was obtained from this system. Multilayer perceptron (MLP) neural network is used to estimate biomass concentration using secondary process parameters such as dissolved oxygen (DO), temperature, pH and agitation speed as inputs. Different models are developed based on different batches of production data and various network architecture in order to study the appropriate integration of process data and network topology that gives the best model accuracy. Results indicate that the biomass soft-sensor developed using MLP-ANN provides a better estimate of biomass in comparison to radial basis function (RBF) neural network and support vector regression (SVR) methods. The developed soft-sensor can be further used in monitoring and control of production output.
Effect of Grouser Movement to Sand-Grouser Interaction on Unconsolidated Soft Sand Incline Using Discrete Element Method (DEM) Simulation
Authors: Sabarudin S.S. , Ibrahim A.N. , Jamaludin A.S. , Fukuoka Y.
Published: June 2020

Wheel rover is a lightweight robot that is used for driving over rough terrain such as on unconsolidated sandy dune incline. Typically, a rover is equipped with fixed grousers on its wheels (conventional grousers). A problem that usually occurs by using conventional grousers is the rover getting stuck on an unconsolidated sandy dune incline as the wheel tends to slip and sink into the sand. This happens when the conventional grousers rotate and moves the sand from below of the wheel to the back of the wheel causing sand accumulated behind the wheel. A solution to minimize sand movement and subsequent sinkage to prevent this problem has been purposed during previous research where a prototype of a wheel rover which uses “adjustable grousers” with adjustable angles. During comparison experiments by previous researcher, the result shows that the length of fixed grousers affect the performance of the wheel in soft terrain and shows high tendency to get stuck in the sand. The purpose of this study is to investigate the interaction between the rotating motion of a fixed grouser and the sand movement by means of computer simulation. By utilizing computer simulation, the parameters that affects the movement of sand particles was observed. For the simulation process, Discrete Element Method (DEM) is used. The result shows that the longer grouser has higher average of sand displacement and moves higher volume of sand under the rotating wheel. The result will be used to assist in analysing the optimal parameters for wheel design for use on soft sand.
A Study on Fatigue Reduction of Driver by Changing Back Support Position During Long Time Driving
Authors: Yamakawa T. , Asano K. , Yoshida M. , Tsutsumi S. , Hayakawa S. , Ikeura R. , Tsutsui T. , Tobata H.
Published: June 2020

Our main study theme is to reduce fatigue of driver during long time driving. In order to reduce fatigue of drivers during long time driving, we focused on a method of using back support mechanisms to change the posture of the driver. We predicted that fatigue level of driver would change in accordance with the change of back support position. Furthermore, we evaluated the muscle activity change when the support position changed. By examining the correlation between the evaluated data, we expected that the driver’s optimum support position would be found out. As a result of conducting driving and subjective assessment, it was found that there was a difference in fatigue reduction effect on the change of the driver’s back support position. When the driver’s fatigue level was low, muscle activity was low.
Voice Command Intelligent System (VCIS) for Smart Home Application using Mel-frequency cepstral coefficients and linear prediction coefficients
Authors: Mohd Ali Yusnita , Mokhtar Nor Fadzilah , Noorsal Emilia , Zulhanip Aida Zulia , Zanal Asmalia , Md Saad Siti Zubaidah , Abdul Samad Nur Aliza
Published: June 2020

Voice recognition, command and control systems have played a vital role to facilitate our modern lifestyle and routine operations through hands-free applications. Working people are busy with their routines, simple tasks such as to on/off electrical appliances at home are often overlooked leads to wastage of energy. Besides, the elderly and handicapped often face difficulties to control the electrical appliances due to their physical disability. To overcome, this project aims to develop a voice command intelligent system (VCIS) as an aid to these routine tasks such as to switch on/off a lamp, control a motor and control other modes of operation of home appliances using voice interface. In particular, VCIS involves several development processes such as database collection, pre-processing, feature extraction algorithms and classification modeling for application in smart home. This paper proposes three hierarchical stages in VCIS. The experimental results show that Mel-frequency cepstral coefficients (MFCC) surpassed linear prediction coefficients (LPC) to correlate with the voice commands in all classification stages using artificial neural network. The classification rates were successfully accomplished, 99.12% (MFCC) and 95.23% (LPC). In conclusion, the proposed VCIS can be employed as an efficient method for better quality of life.
Fabrication and Characterization of Light Emitting Diode Based on n-ZnO Nanorods Grown Via a Low-Temperature
Authors: Mohammad Sabah M. , Abd-Alghafour Nabeel M. , Hassan Z. , Ahmed Naser M. , Ahmed Ali Amal Mohamed , Abdalrheem Raed , Abdullah Mundzir
Published: June 2020

In this work, we report the fabrication of a near- ultraviolet (UV) light emitting (LED) device based on the growth of n-ZnO nanorod (NRs) arrays on the p-GaN layer/sapphire substrate heterostructure using the low-cost hydrothermal technique. Morphological, structural and optical properties of the as-fabricated sample are described. The room temperature current-voltage (I–V) measurements of the fabricated LED device confirmed a rectifying diode behaviour. The device presents near UV color under reverse bias. The luminescence properties of were investigated from both sides of the fabricated LED device at room temperature by electroluminescence (EL). EL spectrum of color emitting LED composed of intense peaks centered at 367 nm, 379 nm and a broad band around green emission. EL emission for the device has seen with the naked eye under normal light.
Effect of Thickness and Doping Concentration of Aluminium to the Fabrication of ZnO Photoconductive Sensor
Authors: Abdullah Mohd Hanapiah , Jumidali Mohd Muzafa , Yuseri Nur Yasmin , Mohamed Yusoff Syarifah Adilah
Published: June 2020

The effect of thickness of aluminium doped zinc oxide (AZO), doping concentration of Aluminium as well as the annealing temperature to the fabrication of AZO photoconductor sensor is the main focused of this research. Silvaco TCAD tool is used to fabricate the AZO photoconductor sensor and to obtain the electrical characteristics of the device by using its simulation software. The device performance was investigated with various thicknesses of AZO film, annealing temperatures and different Al doping concentration. The Al doping was varied 1×1017 cm−3, 1×1019 cm−3 and 1×1021 cm−3, the thickness was varied 0.2 nm, 1.0 nm and 1.2 nm and the temperature was varied from 300°C, 500°C and 700°C. The electrical properties of AZO photodetector were characterized using current voltage (I-V) measurement system respectively. The result shows that by changing the thicknesses of aluminium doped zinc oxide (AZO), and the doping concentration of aluminium in the zinc oxide have greatly improved the electrical characteristics as well as the electrical performances of the photoconductor sensor. Indeed, the post fabrication and simulation process using simulation tools is helpful for the determination of the parameters during the later process of the real device fabrication.
Synthesis of Anodic TiO2 Nanotube Arrays Annealed at 700°C for UV Photodetector
Authors: Chahrour Khaled M , Yam F K , Lim H S , Abdalrheem Raed
Published: June 2020

Anodic titanium dioxide (TiO2) nanotube arrays on Ti foil were synthesized using electrochemical anodization technique and annealed at 700 °C without annihilating the nanotubular assemblies. The nanotubular structure was used to fabricate UV photodetection device based on Metal-Semiconductor-Metal. The photodetection device exhibited UV-sensitive photoresponse characteristics due to the mixed anatase and rutile phases of the TiO2 nanotube arrays. The photoresponse analysis showed good sensitivity to UV light irradiation with excellent stability and reproducibility. Moreover, the UV photodetector revealed the current gain is 7, response time is 0.77 s and decay time is 0.79 s, respectively at biased voltage 4 V. As mentioned above, the UV photodetector based on mixture of anatase and rutile phase nanotube arrays is a recommended nano-optoelectronic apparatus that is remarkably applicable over Ultraviolet band.
Fabrication of Deep Green Light Emitting Diode on Bulk Gallium Nitride Substrate
Authors: Abdul Rais Shamsul Amir bin , Hassan Zainuriah , Abu Bakar Ahmad Shuhaimi bin , Abdul Rahman Muhammad Nazri bin , Yusuf Yusnizam bin , bin Md Taib Muhamad Ikram , bin Sulaiman Abdullah Fadil , binti Hussin Hayatun Najiha , bin Ahmad Mohd Fairus
Published: June 2020

The indium composition in InxGa1-xN/GaN multi-quantum well structure e(MQW) is crucial because lower indium composition will shift the wavelength towards ultraviolet region. Nevertheless, at certain indium content in MQW, it will out diffuse from the MQW resulting in the wavelength shift from green to much shorter wavelength, after the annealing process for p-type activation. In this study, we had grown a full Light Emitting Diode device with the MQW layer at a relative high temperature for green LED with indium pre-flow at the top of n-type layer just beneath the MQW using Metal Organic Chemical Vapor Deposition (MOCVD). Transmission Electron Microscopy (TEM) image of the MQW prior and post the activation of p-type had been observed, which resulted in good contrast, showing the abruptness of the MQW layer of the device. Homogenous layers of InxGa1-xN/GaN has been observed. We also managed to reduce the wavelength shift of the device significantly. The optical, crystal properties of grown devices had been studied.
A Development of Plantar Pressure Sensor for Foot Ulcer Detection in Diabetic Neuropathy Individuals – A Pilot Study
Authors: Damanhuri Nor Salwa , Othman Nor Azlan , Wan Zaidi Wan Fatimah Azzahra , Abdullah Samihah
Published: June 2020

Diabetes mellitus is a metabolic disorder that derived from the body’s inability to attain glucose homeostasis. Further increase in glucose level in the bloodstream, if left untreated, will lead to further metabolic disorder and complication such as amputation of a lower limb that caused by a foot ulcer. Approximately, 60% of diabetic foot ulcer comes from neuropathy. Thus, an early detection of foot ulcer would benefit particularly for diabetes individuals to reduce the risk of amputation. In this research, a plantar pressure sensor system is developed by using the Flexiforce sensor with data acquisition of NI-USB6008 as an interface to gather measurement data. There are four Flexiforce sensors that are placed at the most identified points at the right foot, which are heel, mid foot, fore foot and toe. In this pilot study, the right foot was chosen to be tested with this system. Further analysis was carried out to distinguish between 3 healthy individuals and 3 individuals with diabetes based on gathered plantar pressure value. A correlation study was performed between plantar pressure data and blood glucose data at t = 0 (G
0) to further justify the result before distinguishing the metabolic state of the individual. Although results show no significant different (p<0.05) between these two groups based on 4 measurement points, this research provides a promising finding as some of the pressure reading of diabetes patients are significantly higher than a normal person. Hence, early detection of a foot ulcer is a good indicator that can significantly reduce diabetes-related foot complications through early education and appropriate foot care. This early detection of a foot ulcer also could benefit a better diagnosis and reduce subsequent risk and impact on diabetes-related foot complications.
Temperature effects on electrical and structural properties of MEH-PPV/PEIE OLED Device
Authors: Ismail N A N , Shaari S , Juhari N , Sabani N , Ahmad M F , Zakaria N F
Published: June 2020

This paper explores the performance of configuration ITO/MEH-PPV/PEIE/Al OLED under the variations of temperature. The MEH-PPV and MEH-PPV/PEIE thin film were deposited on ITO substrates using spin coating technique with fixed spin speed of 3000 rpm and baked at low temperature ranging from 90 °C to 180 °C, respectively. The surface roughness values for MEH-PPV and MEH-PPV/PEIE films were analysed using AFM with 5 μm × 5 μm scanning area. The roughness of MEH-PPV thin films were reduced from 2.825 nm to 1.625 nm when temperature increased. Contrary to MEH-PPV/PEIE films where the roughness increased linearly up to 3.397 nm when the temperature increased. The maximum absorption peak spectrum obtained from UV-Visible (UV-Vis) was found at 500 nm to 510 nm when baked temperature were varied. Furthermore, the turn on voltage from J-V characteristics gives no specific pattern across different temperature and agreed with the trend of surface roughness values. The turn-on voltage at T = 150 °C gives the lowest value of 3 V. Overall, the variations of low temperature gives an effects on structural and electrical properties of this OLED configuration.
Optimization of Titanium Dioxide Layer Fabrication Using Doctor Blade Method in Improving Efficiency of Hybrid Solar Cells
Authors: Kamarulzaman Nurul Huda , Salleh Hasiah , Dagang Ahmad Nazri , Mohd Ghazali Mohd Sabri , Ishak Nurhayati , Ahmad Zakiyah
Published: June 2020

Hybrid solar cell (HSC) in a form of novel photovoltaic is considered among promising research topic due to its low cost’s preparation and environmental friendly solar cells. This paper concerns a systematic study on concentration of TiO2 and effect of coating techniques towards solar cells’s efficiency. However, this paper is limited to doctor blade and spin coating techniques only. These samples were then characterised based on morphology, thickness, optical absorption, electrical conductivity and solar cell’s efficiency using various techniques including FESEM, profilometer, UV-Vis and, autolab with irradiance of 100 mW/m2. From the results, TiO2/PEDOT:PSS with dye Eugenia clavifora (EC) obtained the highest efficiency of 1.33% using doctor blade technique compared to 0.00108% for spin coating technique. Sample thickness was obtained at 60.25 ± 1.20 nm corresponding to the concentration of TiO2 at 0.20 M. Thus, it can be conclude that, power conversion efficiency (PCE) was dependent to the deposition techniques of the thin film.
Investigation on the characteristics of ZnO and ZnO-Pb structure for gamma radiation detection
Authors: Ahmed Ali Amal Mohamed , Ahmed Naser M. , Kabir Norlaili A. , Mohammad Sabah M.
Published: June 2020

Zinc oxide (ZnO) thin films of multilayers structure were fabricated by chemical bath deposition (CBD) method on a glass substrate. After growing, the optical, structural and morphological characterizations of the samples were studied. Moreover, the crystallite size and energy band gap were calculated by using X-ray diffractometer (XRD) and UV-visible spectrometer, respectively. XRD showed that the crystalline size of the samples decreased with increasing the layers up to four layers, while the energy band gap increased with increasing the layers. Field emission scanning electron microscope (FESEM) used to study the morphological properties of the samples. Based on the effective atomic number, electron density and light yield properties of the samples make it suitable to be used as an ionizing radiation detector. Eventually, the samples will be used as a scintillator material to detect ionizing radiation.
Effects of Post-Deposition Annealing Time in Forming Gas Ambient on Y2O3 Films Deposited on Silicon Substrate
Authors: Lim Way Foong , Cheong Kuan Yew , Hassan Zainuriah , Quah Hock Jin
Published: June 2020

Effects of post-deposition annealing (PDA) time (15, 30, and 45 min) at 800°C in forming gas (95% N2-5% H2) ambient was systematically studied for RF-magnetron sputtered Y2O3 films on n-type Si(100) substrate. X-ray diffraction characterization has revealed the detection of Y2O3 phase oriented in (400), (440), (541), and (543) planes for all of the investigated samples. In addition, capacitance-voltage characteristics of the investigated Al/Y2O3/Si-based metal-oxide-semiconductor capacitors were also presented in this work.
The influence of alkanolamine in the formation of Pt nano- and microstructures
Authors: Johan Ooi M D , Abdul Aziz A , Mahmood A , Bakhari N A
Published: June 2020

Start your abstract here Pt nano- and microstructures have been produced by a solvothermal technique in the presence of diethanolamine (DEA) as a reducing and capping agent. The effect of DEA concentration on Pt properties (structural and morphological) was discussed in detail. A lower DEA concentration produces nanoscale size particles while at higher concentration results in micro-flower structures. Pt crystallinity is enhanced with respect to the increment of DEA concentration in the order of 0.43 M >0.29 M >0.14 M. The presence of amino groups is confirmed by the intense band at ∼1087 cm−1 and absorption peak at 1446 cm−1 corresponds to C-N and N-H bending vibration mode of the amine group. The UV-Visible adsorption peak at 282 nm, due to adsorption of Pt (IV) disappeared implying that the Pt (IV) species has been reduced to Pt (0) valent confirming that DEA acted as a reducing agent. A possible reaction mechanism has been proposed.
Optical limiting behaviour of linear fused ring dichloro-substituent chalcone isomers
Authors: Abdullah Mundzir , Zainuri Dian Alwani , Arshad Suhana , Razak Ibrahim Abdul , Yann Heng Han , Mohammad Sabah M , Mohd Shazlan Siti Nur’Adiilah
Published: June 2020

The third-order nonlinear optical response of halogen anthracenyl chalcone isomers in dimethyl sulphonate (DMSO) as the solvent has been studied. Single beam Z-scan technique at 532nm of laser excitation wavelength is used to determine magnitude and sign of the nonlinear refractive index (n2) and nonlinear absorption coefficient (β). The samples exhibited a self-focusing effect with a negative from the closed aperture z-scan analysis. The n2 is observed to be 10−8 cm2/W. Open z-scan data showed reverse saturable absorptions with significant β for both samples. The magnitude of β is of the order of 10−4 cm/W. Optical limiting studies show a decrement in transmittance as a function of input fluence. Optical limiting action begins at as low as 20 kW/cm2 of focal input intensity which is ideal for low powered continuous wave laser limiting applications. From the third-order nonlinear properties results, the compound is recommended for optoelectronic and photonics application.
Role of RF Magnetron Sputtering Power on Optical and Electrical Properties of ITO Films on Soda-Lime Glass Substrates
Authors: Asri R.I.M. , Hamzah N.A. , Ahmad M.A. , Md Taib M.Ikram , Sahil S.M.S. , Hassan Z.
Published: June 2020

The optical and electrical properties of indium tin oxide (ITO) thin films grown on soda-lime glass substrates using a radio frequency (RF) magnetron sputtering technique were studied as a function of the sputtering RF power. Fixed 100 nm thickness of ITO films were deposited on the soda-lime glass substrates at 300 °C, using RF powers ranging between 50 to 150 W. The optical and electrical properties of the sputtered ITO films were characterized by Ultraviolet–Visible Spectroscopy (UV-Vis), Hall Effect Measurement and Atomic Force Microscope (AFM). Varying the substrate temperature and RF sputtering power affected surface roughness to decrease from 5.80, 4.59 and 3.46 nm while the resistivity also decreased from 18.73 x 10−4, 6.484 x 10−4 and 2.421 x 10−4 Ω.cm. Deposition of ITO thin films on soda-lime glass substrates by RF magnetron sputtering at 300 °C substrate temperature contributed to 74 to 79 % of optical transmittance in the 450 nm region. Results of this study suggested that a better performance of both optical transparency and electrical conductivity of ITO films can be achieved by operating at high temperature substrate and high level of sputtering power.
An investigation on FR4 as a based material for Ti/Au and Cu/Au evaporated fabrication for DNA biosensor application
Authors: Hamzah I H , Rahim A F A , Zulhanip A Z , Idris M , Malik A A
Published: June 2020

Glass fabricated with Ti/Au is a common technique for DNA in biosensor application. However, the wet etching technique produced poor adhesion for the Ti/Au on the glass. FR4 had been investigated to be used as a based material in this research. Three types of thermal evaporated methods for metal fabrication are investigated; Ti/Au, oxidized Cu/Au, and non-oxidized Cu/Au. In this research, Ti and Cu acts as adhesion layer for Au. A 2 cm length, 1.2 cm width and 1.6 mm thickness of FR4 was used as a base material. The FR4 was cleaned sequentially with acetone and isopropanol then left to dry with nitrogen gas. RF sputtering method is used to deposit Ti whereas copper layer (Cu) remained as it is on the FR4. The Cu/FR4 is cleaned sequentially with acetone and isopropanol and dried with nitrogen. It is found that the adhesion of Ti is good and worked on the FR4 surface. However, a major problem arises when the Ti/Au layer is unsuccessfully removed during the wet etching process. The result shows that non-oxidized Cu/Au fabrication worked well on FR4 as well as during wet etching technique. Hence, it is concluded that FR4 can be used as an alternative based material for Au evaporation in biosensor application. The first section in your paper.
Effect of Laser Ablation on Light Output in LED
Authors: Chandran H. , Poopalan P.
Published: June 2020

Surface roughening is a technique used to modify the light extraction efficiency (LEE) from a LED die. UV laser ablation was used to roughen the backside surface of LED dies by creating pore like structures which would enhance the light output. Measurements of light output before and after laser ablation were taken and modifications of the light output were analysed. The ablating source used was a 248nm pulse focused laser.
The Growth of AlN Single Layer on Sapphire at Low Pressure using Metalorganic Chemical Vapor Deposition (MOCVD)
Authors: Sahar M.A.A.Z. Md , Hassan Z. , Lim W.F. , Samsudin M.E.A. , Hanafiah A.M. , Yusuf Y. , Ahmad M.A. , Hamzah N.A. , Asri R.I.M.
Published: June 2020

In this work, aluminium nitride (AlN) single layer has been successfully grown on c-plane sapphire using metalorganic chemical vapor deposition (MOCVD) at low reactor pressure. The effects of growth temperature, ammonia (NH3) flux and trimethylaluminum (TMAl) flux towards AlN growth were investigated. It was noted that the reaction between NH3 and TMAl has affected the growth rate across the growth temperature. Field emission scanning electron microscopy (FESEM) equipped with Energy-dispersive X-ray (EDX) have revealed the formation of AlN single layer on the sapphire substrate and elemental composition of the layer, respectively. The dependence of growth rate on growth temperature, TMAl flux and NH3 flux has been observed. A relationship was drawn, whereby an increase in TMAl flux and decrease in NH3 flux would lead to an increase in the AlN growth. In addition, a drastic increase in the AlN growth was observed at high growth temperature, which was more than 1100°C. Furthermore, observation from atomic force microscopy (AFM) indicated improvement on surface roughness as growth rate increases. Further characterization was carried out using phase analysis using high resolution X-ray diffraction (HRXRD).
Comparative Studies between Porous Silicon and Porous P-Type Gallium Nitride Prepared Using Alternating Current Photo-Assisted Electrochemical Etching Technique
Authors: Sohimee S. N. , Hassan Z. , Ahmed Naser M. , Radzali R. , Quah H. J. , Lim W. F.
Published: June 2020

Porous n-type Si and porous p-type GaN nanostructures were fabricated using alternating current photo-assisted electrochemical (ACPEC) etching in 1:4 volume ratio of hydrofluoric acid (HF) and ethanol (C2H5OH) for a duration of 30 min. The proposed approach to this work was to study pore formation on the Si and p-GaN substrates in the aspects of morphological and structural changes. The morphological and structural properties of porous Si and porous p-type GaN samples have been studied using field emission scanning electron microscopy (FESEM) measurement, energy-dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), and high-resolution X-ray diffraction (HR-XRD) in comparison to the respective as-grown sample. FESEM analysis revealed that uniform pore size with triangular-like shape was formed in porous Si sample while circular-like shape pores were formed in the porous p-type GaN sample. AFM measurement revealed that the root-mean-square surface roughness of porous Si and porous p-type GaN was 6.15 nm and 5.90 nm, respectively. Detailed investigation will be presented in this work to show that ACPEC etching technique is a viable technique to produce porous nanostructures in different substrates.
Characteristics of Cu-doped ZnO films prepared using magnetron co-sputtering
Authors: Yusof A S , Hassan Z
Published: June 2020

This work reports the fabrication of un-doped and cu-doped zinc oxide (ZnO) films using magnetron co-sputtering technique. The fabricated films were deposited on glass substrates followed by thermal annealing process in an ambient condition for 60 minutes at 400 °C. X-ray diffraction (XRD), ultraviolet-visible (UV-Vis) spectrophotometry, field emission scanning electron microscopy (FE-SEM) and Hall measurement with four-point Van der Pauw method were used to study the crystal orientation, optical properties, surface structure and the resistivity of the deposited films respectively. Polycrystalline films with hexagonal wurtzite structure were observed in the CZO films. The redshift and bandgap narrowing were discussed in optical analysis. The trend in bandgap narrowing was contributed by the hybridization of O 2p and Cu 3d band. Hall effect measurement showed that the resistance of deposited Cu-doped ZnO (CZO) films will increase at excessive-high Cu doping level.
Polyester-graphene primer coatings: corrosive and mechanical properties
Authors: Hasniraaiman A H , Zuliahani A , Ishak M A M , Faiza M A , Azniwati A A
Published: June 2020

This study developed and characterized of the polyester (PE)-graphene (GR) primer coating in corrosion resistance and mechanical properties. PE coatings varied with 0-8% of GR were prepared using ultrasonication method and undergone the morphology characterization using Field Emission Scanning Electron Microscopy (FE-SEM), and also being evaluated using various corrosion and mechanical tests, namely tafel test, immersion test, adhesion test and hardness test. The FE- SEM analysis shows that the homogeneous dispersion of GR in PE resin at 2% of GR loading, whilst at higher loading of GR produced agglomeration that reduced the corrosion inhibition properties of the coatings. The corrosive properties were characterized using autolab potentiostat for determination of corrosion rate and immersion testing using 3.5% NaCl for 9 days. The results show that the optimum corrosion rate of coatings was found at 2% of GR loadings which is 0.586 mmpy. This is due to at 2% GR is optimum as a physical barrier and inhibit the diffusion pathways of corrosive species as there is no agglomeration of GR which is showed that very well dispersion of GR in the PE resin. Whilst, immersion observation also shows the optimum condition at 2% of GR loading, which has a lower corrosion property. On the other hand, adhesion and hardness testing were enhanced by increasing of GR loadings (0-8%) as the properties of GR imparted high strength, rigidity, and durability. Therefore, the incorporation of GR is very efficient materials to enhance both mechanical and corrosive properties of polymeric coatings.
Performance Study of Watermelon Rind as Coagulants for the Wastewater Treatment
Authors: Muhammad Arbanah , Rashidi Ahmad Ramli , Roslan Azmi , Shah Buddin Meor Muhammad Hafiz
Published: June 2020

The scarcity of fresh and hygienic water sources leads to a demand of more research for the treatment of wastewater. One of the possible ways is using a watermelon rind as a natural coagulant where its performance was investigated in terms of turbidity, pH and BOD. Watermelon rind (WR) and alum(A) at different compositions (WR100, WR50A50, WR70A30, A100) were introduced in the synthetic wastewater before treated on natural wastewater by jar test. Results revealed that the turbidity, pH as well as dissolved oxygen level were highly dependent on the coagulant dosage. About 90% of turbidity was reducing at 70% of powdered watermelon rind and 30% alum (WR70A30) on the contrary only 72% in natural wastewater. In addition, WR70A30 had better reduction in turbidity as compared to using 100A. On the other hand, final pH reading falls approximately in the range of 6 to 8, respectively which is acceptable for the standard wastewater discharge. Meanwhile, the results for the BOD5 for the natural wastewater is in the ranges between 0.35 to 1.39 had met the WHO standard. Finally, the FTIR analysis on treated and untreated watermelon rind confirms similar peaks of functional groups. Overall, the present study on WR as coagulant show a good performance in treating both natural and synthetic wastewater.
Hundred-year spatial trajectory of lake coverage changes in response to human activities over Wuhan
Authors: Wang Jialin , Cai Xiaobin , Chen Fang , Zhang Zhan , Zhang Yufang , Sun Kun , Zhang Tianhao , Chen Xiaoling
Published: June 2020

Environmental changes induced by ongoing anthropogenic activities have caused severe lake degradation. Because of the lack of long-term records, few studies have investigated the change in Wuhan lakes, and the effect of human activities on regional lake changes prior to 1973 has not been systematically studied yet. Therefore, in this study, historical maps and Landsat images were combined to track these changes from the 1920s to 2015. Three phases could be identified over the nearly 100-year study period. The most dramatic lake reduction (−21.53 km2 yr−1) occurred during Phase II (1950s–1980s) rather than Phase III (after the 1980s), as indicated by previous studies; the decreased lake area in Phase II was almost double that in Phase III. This reduction could be attributed to major hydraulic engineering projects during Phase II based on the watershed-scale analysis. In addition, land-use conversion over the past 45 years was used to quantify the impact of human exploitation on lakes. The shrinkage of lakes was predominately driven by agricultural activities, such as reclamation (39.2%) and aquaculture development (29.0%), and urbanization was a secondary driving force (19.8%), despite the rapid economic development of Wuhan. This study therefore provides a practical guide for lake protection in other areas similar to Wuhan.
A retrospective study of the 2012–2016 California drought and its impacts on the power sector
Authors: Kern Jordan D , Su Yufei , Hill Joy
Published: June 2020

Over the period 2012–2016, the state of California in the United States (U.S.) experienced a drought considered to be one of the worst in state history. Drought’s direct impacts on California’s electric power sector are understood. Extremely low streamflow manifests as reduced hydropower availability, and if drought is also marked by elevated temperatures, these can increase building electricity demands for cooling. Collectively, these impacts force system operators to increase reliance on natural gas power plants, increasing market prices and emissions. However, previous investigations have relied mostly on ex post analysis of observational data to develop estimates of increases in costs and carbon dioxide (CO2) emissions due to the 2012–2016 drought. This has made it difficult to control for confounding variables (e.g. growing renewable energy capacity, volatile natural gas prices) in assessing the drought’s impacts. In this study, we use a power system simulation model to isolate the direct impacts of several hydrometeorological phenomena observed during the 2012–2016 drought on system wide CO2 emissions and wholesale electricity prices in the California market. We find that the impacts of drought conditions on wholesale electricity prices were modest (annual prices increased by $0–3 MWh−1, although much larger within-year increases are also observed). Instead, it was an increase in natural gas prices, punctuated by the 2014 polar vortex event that affected much of the Eastern U.S., which caused wholesale electricity prices to increase during the drought. Costs from the drought were very different for the state’s three investor owned utilities. Overall, we find that increased cooling demands (electricity demand) during the drought may have represented a larger economic cost ($3.8 billion) than lost hydropower generation ($1.9 billion). We also find the potential for renewable energy to mitigate drought-cased increases in CO2 emissions to be negligible, standing in contrast to some previous studies.
Study of Water and Sediment Quality and Heavy Metal Pollution (Pb) at South Kalimantan Mangrove Ecosystem
Authors: Kadarsah Anang , Salim Dafiuddin , Husain dan Sadang
Published: June 2020

Changes in the water quality, sediment, and the presence of heavy metals in the environment have a close links with human activities including the presence of pollutants in the mangrove ecosystem. The purpose of this study is to compare water and sediment quality as well as heavy metal pollution from lead (Pb) in mangrove ecosystems affected by anthropogenic activities (oil palm plantations and mining) in South Kalimantan. The research was carried out for 4 months (June until September 2019) from four villages (Kuala Tambangan, Bunati, Angsana and Setarap) in South Kalimantan Province. The purposive sampling method is used for sampling, which is determined in estuary, middle and inland parts, based on the area division of mangrove ecosystem. Data analysis was performed descriptively while differences in each location were tested using bivariate analysis (Pearson). The results showed that the water quality at the four observation sites was above the standard of Government Regulation number 82 of 2001. There are four values with the highest parameters found in the village of Kuala Tambangan, the first is total dissolved solids (TDS) that reaching ± 8.005 mg / L, nitrite (NO2) as N (± 0.13 mg/L), nitrate (NO3) as N (±0.11 mg/L) and color levels that reach ±129.33 ptCo. The other two highest parameters in Setarap Village are turbidity and dissolved oxygen. Turbidity value reaches ± 16.01 NTU while dissolved oxygen (DO) value is around ±5.92 mg/L. The highest pH value can be found in Bunati Village (± 7.54). The average value of heavy metals in Lead (Pb) is also above the standard of the Minister Decree of Environment in 2004, recorded in waters 0.04 - 0.36 mg/L (highest in Angsana Village ±0.31 mg/L) and sediment 0.01 - 17.43 mg/L (highest in Angsana Village ±15.05 mg/L). The highest water content in sediment comes from Kuala Tambangan village (±6.6%), while the highest organic sediment content is found in Angsana village (±7.8%). Bivariate analysis results used to determine differences between sampling locations showed that the levels of Nitrite (NO2) as N (α = 0,000), Nitrate (NO3) as N (α = 0,000)), pH (α = 0,000), Color (α = 0,000), and Dissolved Oxygen (DO) (α = 0,000), sediment water content (α = 0,000) and heavy metal Pb content in water and sediment (α = 0,000) are differ between mangrove ecosystems in Angsana and Setarap Village.