bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison between CNT Thermal Interface Materials with Graphene Thermal Interface Material in Term of Thermal Conductivity
Authors: Mohamed Mazlan , Omar Mohd Nazri , Ishak Mohamad Shaiful Ashrul , Rahman Rozyanty , Yahaya Nor Zaiazmin , Razab Mohammad Khairul Azhar Abdul , Thirmizir Mohd Zharif Ahmad
Published: September 2020

Thermal interface material (TIM) had been well conducted and developed by using several material as based material. A lot of combination and mixed material were used to increase thermal properties of TIM. Combination between materials for examples carbon nanotubes (CNT) and epoxy had had been used before but the significant of the studied are not exactly like predicted. In this studied, thermal interface material using graphene and CNT as main material were used to increase thermal conductivity and thermal contact resistance. These two types of TIM had been compare to each other in order to find wich material were able to increase the thermal conductivity better. The sample that contain 20 wt. %, 40 wt. % and 60 wt. % of graphene and CNT were used in this studied. The thermal conductivity of thermal interface material is both measured and it was found that TIM made of graphene had better thermal conductivity than CNT. The highest thermal conductivity is 23.2 W/ (mK) with 60 w. % graphene meanwhile at 60 w. % of CNT only produce 12.2 W/ (mK thermal conductivity).
Effect of Alumina (Al2O3) to the Properties of Whiteware Porcelain
Authors: Yahya Hamdan , Ahmad Aspaniza , Ismail Ibrahim
Published: September 2020

The effect of Al2O3 to the properties of whiteware porcelain such as water absorption, bulk density, flexural strength and crystalline phases were studied systematically. The result shows that the addition of alumina at maximum 5 wt.% in porcelain bodies increased the flexural strength of the fired bodies which can reach 55.5 MPa, 30% higher than 0.0% alumina content. However, slight decrease in the other physical and mechanical properties was observed with Al2O3 addition higher than 5 wt.%, which is believed to be due to increased corundum phase compared to mullite phase in porcelain body.
Effect of Milling Parameters on the Structural, Microstructural and Physical Properties of Alumina-Titania-Graphite Nanocomposite
Authors: Ismail Farah Wahida , Razali Mohd Hasmizam , Nik Yusoff Nik Nurul Anis , Yusoff Mahani
Published: September 2020

Al2O3-TiO2-graphite nanocomposite can be used as alternative material for coating application. Fine composite coating particles is commonly produced by milling in a high energy ball milling. This study focused on evaluate the effects on the structural, microstructural and physical properties of Al2O3-TiO2-graphite nanocomposite. The alumina, titania and graphite powder were milled in a planetary ball mill at 2, 4, 8 and 10 h and 200, 250 and 300 rpm. The composite particles was compacted for green density determination. The phase analysis and microstructure of nanocomposite were characterized using X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM). Increasing milling time and milling speed contributes to a small solubility between Al2O3 and TiO2. Increasing milling time and speed decreased the Al2O3 crystallite and internal strain increased as a result of continuous impact on the powder and repeated collision between powder and the wall container. Higher milling time and speed produce finer and flaky shape of Al2O3-TiO2-graphite particles which then affects the green density of the composite.
Prediction Model and Influence of Fe2O3 on the Mechanical Properties of Porcelain with POFA as Quartz Replacement
Authors: Durumin-Iya Sani Garba , Noh Mohamad Zaky , Sharip Norazreen , Ab Razak Siti Noraiza , Rashid Mohd Warikh Abdul , Mohamed Julie Juliewatty , Muhamad Nor Mohd Al Amin
Published: September 2020

Palm oil fuel ash (POFA) is solid waste from palm oil industries discarded after burning of shell, fiber, kernel and empty fruit bunches to heat boiler and generate electricity. A standard porcelain consisting of clay, feldspar and quartz is produced by sintering at temperature between 1300 °C to 1400 °C for toughness and translucency. This research developed a prediction model for optimum physical and mechanical properties of porcelain by addition of Fe2O3 at 5 wt.%. Quartz was replaced with POFA powder at 15 wt.% and Fe2O3 was also added at 5 wt.% of POFA mixed with others porcelain composition. Then the powder was dry pressed into pellet at 91 MPa and the samples were sintered at 1150 °C. The bulk density, compressive strength and Vickers microhardness were found to increase by addition of Fe2O3 at 5 wt.%. Prediction model was developed and from the predicted values it is revealed that, the model is efficient and good for the purpose of this research.
Heat Treatment of SS 316L for Automotive Applications
Authors: Adzali Nur Maizatul Shima , Azhar Noor Aaizaa , Che Daud Zuraidawani , Ahmad Zaidi Nur Hidayah , Adnan Sinar Arzuria
Published: September 2020

Stainless steel 316L (SS 316L) is a low carbon-chromium-nickel-molybdenum austenitic stainless steel. Its application in automotive industry include as exhaust housings for catalytic converters and turbocharger. In this research, the tempering heat treatment was conducted by using SS 316L samples. These steels were austenitized at 860°C for 1 hours before doing two tempering process. Austempering was conducted at 360°C for 15 min in the muffle furnace then air cooled while martempering was conducted at 160°C for 15 min in a muffle furnace then quench in water. The corrosion test was carried out using 1.0 M oxalic acid solution for 30 days in room temperature. Hardness test and microstructural observation were carried out for SS 316L before and after corrosion test. Experimental result showed that untreated sample have highest hardness value before and after corrosion test which were 232 HV and 225 HV respectively. The hardness value before corrosion test is 199.7 HV for austempered sample, and 201.3 HV for martempered sample. Untreated sample shows the lowest corrosion rate (0.94×10-3 mpy), followed by austempered sample (1.89x10-3 mpy) and the highest corrosion rate is for martempered sample (2.36×10-3 mpy). After corrosion, under optical microscope observation, martempered steel has more pits than austempered steel. In summary, austempering is the best heat treatment for SS 316L in automotive applications that give high ductility and toughness after heat treatment with high corrosion resistance.
Dielectric and Curing Properties of ZnFe2O4 Loaded Epoxidized Natural Rubber (ENR 25)
Authors: Sukri Suziey Syamimi , Sharifuddin Syifa' Muhamad , Mat Nor Mohd Shukri , Pabli Fathin Asila Mohd , Luangchuang Piyawadee , Chueangchayaphan Wannarat , Sulaiman Muhammad Azwadi
Published: September 2020

Electroceramic with high magnetic properties such as ZnFe2O4 is widely used in many electronic device applications. One of the major drawbacks of electroceramic is the difficulty in molding and processing into desired shapes due to its brittle nature. Flexible electroceramic with the superior process and mold abilities can be made by mixing magnetic ceramic with a flexible matrix, for instance, rubber. In this present study, the aims were to produce ZnFe2O4 loaded epoxidized natural rubber (ENR 25) as well as to determine its electrical and curing properties. The magnetic ceramic of ZnFe2O4 was blended with ENR 25 at different loadings varying from 0 to 120 parts per hundred of rubber (phr) in an interval of 20. The properties of produced composites include scorch time, cure time, torque and dielectric properties were characterised. The results demonstrated that the increase of ZnFe2O4 concentration in ENR 25 leads to a significant increase in the dielectric constant from 4.94 to 5.62 at 1.15 MHz, and decrease in the dielectric loss curves of the composites start from 0.0827 to 0.0586. Furthermore, the results of curing property studies exhibited an increasing pattern of the composite torques, starting from 1.43 to 1.76 dN.m.
Conductivity Study of Cassava Starch Coated Anode for Zinc-Air Fuel Cell System
Authors: Ismail Wan Marinah Izzati Wan , Chien L.J. , Adli Hasyiya Karimah , Salleh Hasiah , Masri Mohamad Najmi
Published: September 2020

In this study, cassava starch (CS) was prepared as conductive biodegradable material on zinc anode (ZnC) in zinc-air fuel cell (ZAFC) by using electrochemistry method. Successful formation of cassava on Zn anode was tested its conductivity by using four-point probe instrument and proven the enhancement of conductivity of anode after the deposition of CS. The optimization of conductivity study was further carried out in different concentrations of cassava. From conductivity analysis, it was shown the increment 30% of conductivity values from original conductivity of pure zinc. Moreover, scanning electron microscopy (SEM) and fourier-transform infrared spectroscopy (FTIR) also were conducted to evaluate the morphology and chemical chain of cassava.
Electronic Properties of Calcium and Zirconium Co-Doped BaTiO3
Authors: Adewale Akeem Adekunle , Chik Abdullah , Zaki Ruhiyuddin Mohd
Published: September 2020

Barium titanate (BaTiO3) is a perovskite based oxides with many potential application in electronic devices. From experimental report BaTiO3 has wide energy band gap of about 3.4 eV which by doped with Ca and Zr at A- and B- sites respectively can enhance their piezoelectric properties. Using first principles method within the density functional theory (DFT) as implement in Quantum Espresso (QE) with the plane wave pseudo potential function, the influence of the Ca and Zr doping in BaTiO3 are studied via electronic properties: band structure, total density of states (TDOS) and partial density of states (PDOS). The energy band gap calculated was underestimation which is similar to other DFT work. Two direct band gap where observed in Ba0.875Ca0.125Ti0.875Zr0.125O3 sample at Γ- Γ (2.31 eV) and X- X (2.35 eV) symmetry point.
Thermoelectric Properties of Sm Doped CaMnO3 Using Density Functional Theory Method
Authors: Chik Abdullah , Zaki Ruhiyuddin Mohd , Adewale Akeem Adekunle , Pa Faizul Che , Yeoh Cheow Keat
Published: September 2020

The electronic structure and thermoelectric properties of CaMnO3 doped with 8% and 17% f block element Sm using first principles calculations and semi-classic Boltzmann theory were presented in this paper. The G-type AFM phase is most stable among five phases for CaMnO3, however, with 8% and 17% Sm doping, these compounds became nonmagnetic phases. CaMnO3 calculated electronic band structure shows an indirect band gap of 0.523 eV, which is underestimated by the density functional theory (DFT) calculations but the band gap explains the semiconducting behavior. However, with 8% and 17% Sm doping, the electronic bandstructure of these compounds exhibit metallic behavior, with Sm and Mn 3d electrons contributing to conduction band, increasing the magnitude of conductivity for doped compounds. All temperature dependence Seebeck coefficient plots show n-typed conduction for all compound with reduced magnitude of Seebeck coefficient for doped compounds. The temperature dependence thermal conductivity plot shows overall thermal conductivity is reduced in Sm doped compound. CaMnO3 with 17% Sm doping exhibit much higher ZT of 0.32 at 800 K showing enhanced thermoelectric properties at high temperature and suitability or high temperature energy conversion devices.
Electrical Behavior of Graphene/SiO2/Silicon Material Irradiated by Electron for Field Effect Transistor (FET) Applications
Authors: Zamzuri Ahmad Syahmi , Ayob Nur Idayu , Abdullah Yusof , Saidin Nur Ubaidah , Hak Cik Rohaida Che
Published: September 2020

In this paper, the detail study of electrical conductivity of single layer graphene (SLG) on silicon dioxide (SiO2)/Silicon substrate irradiated by high energy (MeV) electron is presented. The SLG samples prepared by Chemical Vapor Deposition (CVD) were irradiated by 50 kGy, 100 kGy and 200 kGy doses of electron radiation at energy voltage of 3 MeV. Current-Voltage (I-V) characteristics and conductivity of the pristine and irradiated graphene samples were measured and analysed using I-V measurement at room temperature. The non-linear I-V curves were clearly observed as the voltage reach to 2.0 V for non-irradiated and irradiated samples. This may be attributed to the non-uniform charges by high energy electron irradiation and poor metal contact of the sample. Hysteresis loop form at 2.0 V probably due to the to the charge trapping occurs at the interface of the graphene and SiO2. The reaction of high energy particles lead to creation of more carrier charges that contribute to the increment of conductivity compare to the small number of atom displacement of knock-on collisions with the nuclei of carbon atoms at higher dose. This study provides significant findings on the graphene electrical characteristics when irradiated with high energy (MeV) electron.
Influence of Cobalt Addition on Microstructure and Damping Properties of Cu-Al-Ni Shape Memory Alloys
Authors: Wee Ying Ci , Ghandvar Hamidreza , Abu Bakar Tuty Asma , Hamzah Esah
Published: September 2020

Copper-based shape memory alloys (SMAs) gaining attention due to their high damping properties during martensitic transformation and effective in energy dissipation which is applicable to damping application. However, copper-based SMAs such as the ternary Cu-Al-Ni are not easily deformed in the lower temperature martensitic phase which can be attributed to brittleness induced by coarse grain size, high degree of order and elastic anisotropy. Hence, this study aims to improve the properties of Cu-Al-Ni SMAs by addition of fourth alloying element. In this research, Cu-Al-Ni alloys with the addition of the fourth additional element, cobalt were prepared by casting. Microstructure characteristics of Cu-Al-Ni SMAs with and without Co addition were investigated via scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS) and x-ray diffraction (XRD). Damping capacity was determined by dynamic mechanical analysis (DMA). It was found that the alloy with 0.7wt% of Co addition showed the best improvement on the damping properties.
Comparative Adsorption Isotherm for Beryllium Oxide/Iron (III) Oxide Toward CO2 Adsorption and Desorption Studies
Authors: Lahuri Azizul Hakim , Yarmo Mohd Ambar , Abu Tahari Maratun Najiha , Marliza Tengku Sharifah , Tengku Saharuddin Tengku Shafazila , Fui Mark Lee Wun , Dzakaria Norliza
Published: September 2020

Surface modification of Fe2O3 by adding BeO was synthesized and calcined at different temperatures of 200-600 °C. The adsorbents were characterized by using XRD, N2 adsorption-desorption isotherm prior to performing CO2 adsorption and desorption studies. The CO2 adsorption data were analyzed using adsorption isotherm models such as Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich. BeO/Fe2O3-300 that calcined at 300 °C showed the most efficient adsorbent with physisorption and chemisorption were measured at 5.85 and 45.88 mg/g respectively. The CO2 adsorption notably best fitted with Freundlich isotherm with R2 = 0.9897 and calculated adsorption capacity closest to experimental data. This implies the CO2 adsorption process was governed by multilayer adsorption on the heterogeneous surface of the adsorbent. The mean free energy of adsorption (E=3.536 kJ/mol) from Dubinin-Radushkevich and heat of adsorption (bT=3.219 kJ/mol) from the Temkin model support that the adsorption process is physical phenomena.
Chemical Reduction Behaviour of NiO under Various Concentration of Carbon Monoxide Using TPR and XRD Techniques
Authors: Samidin Salma , Abu Tahari Maratun Najiha , Sulhadi Siti Sarahah , Salleh Fairous , Dzakaria Norliza , Wan Isahak Wan Nor Roslam , Yusop Muhammad Rahimi , Yarmo Mohd Ambar
Published: September 2020

The chemical reduction behavior of NiO under various carbon monoxide (CO) concentration as a reduction agent was studied. The NiO and Ni0 transformations were identified using TPR and XRD techniques. It was shown that, the completed reduction occurred at temperature 700 °C for 40% CO and 900 °C for 10% and 20% CO. During the chemical reduction process, nickel carbide was formed at temperature 400 °C and another formation of carbon amorphous appeared at 500 °C and proved through diffraction of XRD pattern at 2θ: 22.86 under 20% CO/N2 and and 2θ: 26.15 under 40% CO/N2. The interpretation of physisorption data showed that the pore size after reduction with various CO concentration comprised as microporous size in the range of 6-40 nm. Therefore, CO as a mild reduction agent stated that as the concentration of CO high, the rate of reduction affected and formed a very crystalline of Ni0 particle.
Obtaining TiO2 and Fe2O3 from Ilmenite via Alkaline Fusion Method
Authors: Hazan Roshasnorlyza , Muhamad Yusop Muhammad Azri , Paulus Wilfred @ Sylvester , Mohamed Takip Khaironie
Published: September 2020

Tin mining business in Malaysia produce many types of by product such as xenotime, monazite, zircon and ilmenite. Ilmenite is one of the crucial materials that helps the growth of economy in Malaysia. Instead of that, ilmenite becomes an important material in the process of oxygen carrier where it shows a better compare to the other such as olivine, hematite, biotite and cuprite. Incredible mechanical resistance and good thermal properties are playing an important factor for the materials that been used for oxygen carrier and ilmenite is the most suitable material for oxygen carrier process. Instead of its suitable properties, ilmenite also one of the lowest price materials among natural minerals sources. Ilmenite composition can provide titanium dioxide (TiO2) which can be used in many industries such as painting and iron oxide (Fe2O3 or Fe3O4) for catalytic and magnetic industries. TiO2 can be found in three phases which are anatase, rutile and brookite. In order to obtain TiO2, dissolution – precipitation mechanism where titanium arranges into different crystal structure depending on the reactant chemistry. These phase formations were obtained by using hydrothermal treatment at elevated temperatures with the appropriate reactants. The transition temperature and the mechanism of the structural transformation also can be largely influenced the iron oxide phase. Therefor in this study, extractive metallurgy method was used in order to obtain separate TiO2 and Fe2O3.
Self - Cleaning Property of Ag/TiO2 Thin Film
Authors: Razak Kamrosni Abdul , Halin Dewi Suriyani Che , Abdullah Mohd Mustafa Al Bakri , Azani Azliza , Mohd Salleh Mohd Arif Anuar , Mahmed Norsuria , Chobpattana Varistha
Published: September 2020

Ag/TiO2 thin film was prepared by the sol-gel method through the hydrolysis of titanium tetraisopropoxide and silver nitrate solution. Spin coating method was used to get uniform film on ITO glass substrate followed by annealing process for 1 hour. After that, all the samples were characterised using GIXRD and FESEM and undergone water contact angle test and MB degradation. Silver ion concentrations were varied to observe the effect on crystalline state, morphology, wettability and photocatalytic properties. The results showed that Ag/TiO2 thin film was in anatase phase and it could degrade nearly 70% of methylene blue after 150 min illumination. The formed Ag/TiO2 thin film has excellent self-cleaning property with compact, continuous, smooth, and good hydrophilicity property.
Photocatalytic Activity of Bilayer TiO2/ZnO and ZnO TiO2 Thin Films
Authors: Hussin Rosniza , Zulkiflee Nur Syahraain , Zakiah Kamdi , Ainun Rahmahwati Ainuddin , Harun Zawati , Mohamed Hatta Mohamed Nasrul
Published: September 2020

Thin film is a thin material that is resulting from the condensation of species through the deposition of atoms on the substrate. Thin films are usually used in the production of electronic devices, optical coatings, solar cells, and for decorative items. The bilayer of TiO2/ZnO and ZnO TiO2 thin films have some advantages such as can enhance the surface state and surface atomic mobility, which are useful for improving the photocatalytic activity. The motivation to a used double layer of ZnO and TiO2 is to enhance the properties and photocatalytic activity using the different deposition temperature between the layers. The structural of ZnO/TiO2 thin films were studied using X-Ray diffraction (XRD). Field Emission Scanning Electron Microscope (FESEM) was used to determine the surface morphology of ZnO/TiO2 thin films. The photocatalytic activity of ZnO/TiO2 thin films was analysed using the photodegradation of methylene blue (MB) solution. The XRD analysis revealed that highest anatase crystalline phase for TiO2 growth with orientation (1 0 1), while the ZnO crystal phase, zincite occurred at the highest intensity with (1 0 1) orientation.. The bilayer TiO2/ZnO thin film had the highest reaction rate, K, which is 0.0972 h-1 for photocatalytic activity. The characteristics of bilayer TiO2/ZnO and ZnO/TiO2 thin-film is strongly influenced by the calcination temperature and the presence and combination between the two types of materials.
Characterizations on Microencapsulated Sunflower Oil as Self-Healing Agent Using In Situ Polymerization Method
Authors: Baharom Zulkhibri , Idris Maizlinda Izwana , Lee Tee Chuan , Abu Bakar Sharifah Adzila Syed , Abdullah Hasan Zuhudi
Published: September 2020

This paper emphasizes the characterization on the microencapsulation of sunflower oil as self-healing agent. In-situ polymerization method mainly implicates in the microencapsulation process. The analysation of microencapsulated sunflower oil via prominent characterization of yield of microcapsules, microcapsules characteristics and Fourier Transmission Infa-Red Spectroscopy (FTIR). The prime optimization used was reaction time of microencapsulation process in the ranges of 2, 3 and 4 h. The higher reaction time of microencapsulation process resulted in a higher yield of microcapsules. The yield of microcapsules increases from 46 to 53% respectively by the increasing of reaction time from 2 to 4 h. The surface morphology study associating the diameter of microcapsules measured to analyse the prepared microcapsules. It was indicated that microcapsules were round in shape with smooth micro-surfaces. It was discovered that the diameter of microcapsules during microencapsulation process after 4 h reaction time was in average of 70.53 μm. This size was measured before filtering the microcapsules with solvent and dried in vacuum oven. Apparently, after filtering and drying stage, the diameter of microcapsules specifically identified under Field Emission Scanning Electron Microscopy (FESEM) showing the size of 2.33 μm may be due to the removing the suspended oil surrounded the microcapsules. Sunflower oil as core content and UF as shell of microcapsules demonstrated the proven chemical properties on characterization by FTIR with the stretching peak of 1537.99 - 1538.90 cm-1 (-H in-CH2), 1235.49 - 1238.77 cm-1 (C-O-C Vibrations at Ester) and 1017.65 - 1034.11 cm-1 (C-OH Stretching Vibrations). It was showed that sunflower oil can be considered as an alternative nature resource for self-healing agent in microencapsulation process. The characterization of microencapsulated sunflower oil using in-situ polymerization method showed that sunflower oil was viable healant to be encapsulated and incorporated in metal coating.
Comparative Study on Microencapsulated of Natural and Waste Sunflower Oil as Self-Healing Agent
Authors: Baharom Zulkhibri , Idris Maizlinda Izwana , Lee Tee Chuan , Abdullah Hasan Zuhudi
Published: September 2020

Microencapsulation of natural vegetable oil as a self-healing agent on metal coating became demanded lately. This paper underlines the microcapsule containing natural and wastes sunflower oil as a self-healing agent that was fabricated for the backbone of corrosion coatings. The results in this paper indicated the distinguished potential of waste sunflower oil as compared to natural sunflower oil. The diameter of microcapsules synthesized from natural sunflower oil and waste sunflower oil both in range of 3-4 µm. The shell of microcapsules microencapsulated from natural sunflower oil showed rough micro-structure while the shell of microcapsules microencapsulated from waste sunflower oil showed smooth micro-structure. The main parameter studied in this research was the varient of stirring speed during the process of microencapsulation. The involvement of stirring speed starts from 200 to 400 rpm. The microcapsules undergo varient of stirring speed analyzed on the yield and core content of microcapsules. The microcapsules from natural produced 29-50% while waste resources bring 26-48% of yield productions. The core content of microencapsulated natural sunflower oil generates 55-64% core content as comparing with waste sources which produce 56-67% of core content. It can be concluded that it was proved that sunflower oil could be considered as an alternative resource for self-healing agent in metal coating either encapsulated from natural or waste raw materials. The incorporation of green and natural material as a self-healing agent significantly influences the sustaining the environment to the safest stage.
Effect Band Gap of Chitosan Film in Converting Water Vapour Into Electrical Current
Authors: Balyan Muhammad , Nasution Tulus Ikhsan , Nainggolan Irwana , Mohamad Hasmaliza , Ahmad Zainal Arifin
Published: September 2020

In this study, a device called a water vapour cell has been successfully fabricated. A water vapour cell consists of patterned silver on the top layer, chitosan film in the middle, titanium in the bottom layer and isolator substrate as the cover. Chitosan films utilized as a conversion material which works based on direct chemical interactions between chitosan film surface and water vapour to generate electrical current. The chitosan concentration was varied from 0%, 1%, 2%, 3%, 3.25%, 3.5%, 3.75%, 4%, 4.25% and 4.5% (w/v), respectively. The energy conversion properties of a water vapour cell were conducted by exposing water vapour into a water vapour cell. The water vapour was represented by a percentage of relative humidity (RH) which varied from 30% - 90% at 27 °C until 24 hours. It was proven that no electrical current was generated by water vapour cell with 0% chitosan film, while the other concentrations generated stable electrical current once exposed to ≤70% RH. However, the electrical current started to increase and achieved a stable state after 13-11 hours when exposed to ≥70% RH. The highest electrical current was generated 15.31 microampere (μA) achieved by 4% chitosan film under 90% RH exposure. The optical band gap and SEM characterization result indicated that the addition of chitosan concentration higher or equal to 4.25% showed the presence of aggregates which decreased chitosan film band gap into 3.22 and 3.53 eV. Therefore, the higher than 4% concentrations of chitosan have an effect on the physical structure which decreasing the band gap and electrical current.
Effect of Stacking Sequences on Mechanical Properties of Kenaf Hybrid Composites
Authors: Yusuff Ikhwan , Sariffudin Norshahida , Ali Afifah , Hanafi Ismail , Norbahiyah S.
Published: September 2020

In the current project, Kenaf fiber (K) and carbon fiber (C) with epoxy resin were utilized to form carbon-kenaf hybrid composites using a vacuum infusion technique. The volume fraction of fiber and thickness of a hybrid composite was fixed at 40 vol.% and 3mm, respectively. Four different sequences were introduced in the current project including CCCCC, KKKKK, KCKCK, and CKCKC. Mechanical testing such as tensile and flexural tests were performed according to ASTM D3039 and ASTM D790, respectively. Scanning Electron Microscope (SEM) and Optical Microscope (OM) were used to identify modes of failures in both tensile and flexural tests of carbon/kenaf hybrid composites. The hybrid CKCKC sample displayed a higher value in tensile strength (264.23 MPa), tensile modulus (11.06 GPa), flexural strength (438.51 MPa) and flexural modulus (25.13 GPa) as compared than KCKCK hybrid sample.
Isothermal Oxidation Behavior of Fe-33Ni-18Cr Alloy in Different Heat Treatment Temperature
Authors: Zulnuraini Zahraa , Parimin Noraziana
Published: September 2020

This research study describes the influence of different heat treatment temperature on isothermal oxidation of Fe-33Ni-18Cr alloy. The Fe-33Ni-18Cr alloy was undergone heat treatment at three different temperatures, namely 1000 °C, 1100 °C and 1200 °C for 3h soaking time followed by water quench to vary the grain size of the alloy. This alloy was ground by using several grit of silicon carbide papers as well as weighed by using analytical balance and measured by using Vernier caliper before oxidation test. The heat-treated Fe-33Ni-18Cr alloy was isothermally oxidized at 800 °C for 150h. The characterization of oxidized samples was carried out using optical microscope, scanning electron microscope equipped with energy dispersive x-ray (SEM-EDX) and x-ray diffraction (XRD). The results showed that, increasing the heat treatment temperature was increased the average grain size. The kinetics of oxidation followed the parabolic rate law which represents diffusion-controlled oxide growth rate. Fine grain structure of 1000 °C sample shows minimum weight gain and lower oxidation rate compared to samples of 1100 °C and 1200 °C that indicated oxide spallation and porous structure. Besides, phase analysis showed that the oxidized sample formed several oxide phases.
Effects of Ultraviolet (UV) Treatment on the Properties of Black Tilapia Fish Skins Gelatin
Authors: Ismail Norhasikin , Idris Maizlinda Izwana , Abdullah Hasan Zuhudi
Published: September 2020

The aim of the study is to investigate the effects of ultraviolet (UV) treatment on the properties of black tilapia fish skins gelatin. The fish gelatin were investigated in terms of gel strength, functional group and the water contact angle of the gelatin. The UV treatment were irradiated with UVA and UVC at different time (0.5, 1.0, 1.5 and 2.0 h). The gel strength of gelatin gel significantly increases after UV irradiation for both UVA and UVC sample. The water contact angle of the gelatin was categorized as hydrophobic for both gelatin that treated with UVA and UVC which the angle >65°. The interactions and characteristic of functional groups for gelatin that treated with UV were analyzed via Fourier Transform Infrared Spectroscopy (FTIR). Results indicated that employing UV irradiation as an alternative method to enhance some of the quality attributes of fish gelatin.
Linking Spectrograph to Mechanical and Physical Properties of X7475 Experimental Alloys Produced from Recycling Beverage Cans for Bumper Beam Applications
Authors: Kazeem Abubakar , Badarulzaman Nur Azam , Wan Ali Wan Fahmin Faiz
Published: September 2020

The automobile industry intends to consume more aluminium alloys in an effort to reduce the greenhouse emissions through the cut in the weight of the passenger cars. Experimental X7475 aluminium alloy is a good candidate to achieve this mission. Past efforts targeted at exploring the aluminium for bumper beam applications and even the recovery of aluminium from recycled beverage can (RBC) were not with the aim of upgrading the 3xxx to a novel 7xxx alloy. The wt. % of Zn was 5.0, 4.5 and 4.0, while Mg was left at 1.50, 1.25 and 1.00 wt. % with Mn at a peak of 0.075, 0.050 average and a least wt. % of 0.025. Alloys were homogenized and taken through annealing (O), natural aging (T4) and artificial aging (T6). The effect of hardening phases such as MgZn2 (ICDD 034-0457) due to heat treatments on the physical and mechanical properties of the new X7475 alloys was investigated. Formation of precipitates affected the density and hardness of the alloys produced via stir casting route. A least hardness of 63.40 Hv was observed in alloy H with a density of 2.7264 g/cm3 while the maximum of 113.06 Hv was recorded against alloy C in as-cast (AC). The result has contributed to the database of experimental alloys with the possibilities of producing a new material from RBCs for bumper beam applications. Future investigation should employ design of experiment (DOE) in optimization of the heat treatment for better mechanical properties.
Behavior of Osteoclast Cells Response on Dicalcium Phosphate Dihydrate Layer-Coated β-Tricalcium Phosphate Granular
Authors: Shariff Khairul Anuar , Abu Bakar Mohamad Hafizi , Cahyanto Arief
Published: September 2020

The aim of this study is to investigate the behavior of osteoclast cells response on dicalcium phosphate dihydrate (DCPD) layer-coated β-TCP granules. β-TCP granules with 300-600 μm were exposed to acidic calcium phosphate solution for 30 mins in order to get 10 mol% DCPD layer-coated β-TCP granular. DCPD free-coated β-TCP granular had used as control specimen. Both specimens were implant in 9 mm of rat calvarial bone defect for 4 weeks. After 4 weeks, the block section of rat calvarial containing specimen were removed for Tatrate-Resistance Acid Phosphatase (TRAP) analysis. Results of TRAP staining reveal that the number of osteoclast cells attached on 10 mol% layer-coated β-TCP granular is higher than DCPD free-coated β-TCP granular. Since remodeling of new bone formation involved simultaneous osteoclast and osteoblast cells response, therefore, the results obtained in this study indicated that the presence of DCPD layer-coated on β-TCP granular helps to improve osteoclast cells response that contribute in stimulating new bone formation.
Bio-Composite of Sodium Alginate-Titanium Dioxide for Wound Healing Applications
Authors: Bakil Siti Natrah Abdul , Abdullah Hasan Zuhudi , Selimin Mohamad Ali , Lee Tee Chuan , Idris Maizlinda Izwana
Published: September 2020

Sodium alginate is a natural polymer used for many biomedical applications. The excellent biodegradability and biocompatibility of sodium alginate have provided ample space for future development in wound healing applications. In this study, bio-composite film was prepared by solvent casting technique by blending sodium alginate (SA) solution and titanium dioxide (TiO2) followed by crosslinking with calcium chloride. The bio-composite film was characterized with different characterization technique such as Fourier Transform Infrared (FTIR) and X-ray Diffraction (XRD). AFM analysis provides information about surface roughness. The microstructure of bio-composite film was determined by Field Emission Scanning Electron Microscope (FESEM). The wettability of surface material is measure by contact angle. The result demonstrate that the bio-composite film shows high value of surface roughness and contact angle to enhanced blood clotting for wound healing applications
Extraction and Characterization of Natural Hydroxyapatite from Goat Bone for Biomedical Applications
Authors: Ismail Sarfa Azian , Abdullah Hasan Zuhudi
Published: September 2020

Bioactive apatite, which is hydroxyapatite (HAP) with the chemical formula of Ca10(PO4)6(OH)2 have been extensively investigated for biomedical applications in bone and teeth implants due to its biocompatibility characteristics has similar physical-chemical characteristics with human bone. The issues to be highlighted here is to explore the potential of using food waste from goat bone to produce useful natural HAP. This study is to extract natural HAP powder from goat bone waste. The extraction process involved cleaning and boiling process, drying process, crushing, grinding and milling to obtain micron size powder of goat bone and joint. The sample then underwent a calcination process with 900°C, 1000°C, and 1100°C for goat bone and 900°C for goat joint with 3 hours holding time. The characteristic of produced HAP powder was characterised with Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectroscopy (EDS), X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR). The in vitro testing of HAP completed by using Simulated Body Fluid (SBF) and SEM to observe the microstructure of apatite formation. The XRD and EDS results show the HAP crystallinity and Ca/P ratio increase with the increasing of calcination temperature for bone. The bone-like apatite formation appeared in the goat bone and joint sample with calcination temperature 900°C, 1000°C, and 1100°C. The optimum hydroxyapatite is from goat bone sample with calcination temperature 1100°C due to the apatite growth fully cover the surface of the sample with a needle shape structure of the cauliflower structure.
Graphene Oxide Silver Cellulose Alginate for Antibacterial
Authors: Mohd Zin Farah Amanina , Mohamed Noor An'amt , Lee Seong Wei , Sajab Mohd Shaiful , Razab Mohammad Khairul Azhar Abdul , Abdullah Nor Hakimin , Wan Ishak Wan Mohd Faizal , Wong Khairul Nizar Syazwan Salihin , Che Zaudin Nurul Akmar
Published: September 2020

A novel approach for the synthesis of graphene oxide silver alginate has been developed for the antibacterial performance. Graphene oxide (GO) was used as a supporting material towards formation of silver nanoparticle (AgNPs) by a rapid microwave irradiation on mixture of GO and silver complexes and layered on alginate film. The obtained nanocomposite were characterized by using Ultraviolet-visible spectroscopy (UV-Vis), Xray diffraction (XRD) to confirm the formation of GOAgAlginate. The surface morphological studies for the nanocomposite was done by using scanning electron microscope (SEM). Nanometer-sized AgNPs (an average diameter of about 70 nm) with spherical-shape structure loaded on the GO Alginate layer showed a good antibacterial towards E.Coli and Methicillin-resistant Staphylococcus aureus (MRSA).
Surface Properties of Alginate/Chitosan Biofilm for Wound Healing Application
Authors: Idris Maizlinda Izwana , Adzhari Mohammed Firdaus , Bakil Siti Natrah Abdul , Lee Tee Chuan , Selimin Mohamad Ali , Abdullah Hasan Zuhudi
Published: September 2020

This work focuses on the fabrication of film based on natural biopolymers for wound healing application. Alginate and chitosan were choosen because of their oustanding properties such as biocompatible, hydrophilic and non-toxic. Earlier, the biopolymer film was fabricated by using alginate 1% wt and chitosan 1% wt. solutions at volume ratios of 99:1 and 97:3. Next, the biopolymer film solution was cross-linked with 1M CaCl2.2H2O for two hours and later dried for 24 hours at room temperature. Then, the surface properties of the prepared biopolymer films were characterised via Field Emission Scanning Electron Microscopy (FESEM), Atomic Force Microscopy (AFM) and contact angle measurement. It was observed that the surface of the biopolymer film became rougher as the volume of the chitosan increases. This condition was confirmed with average surface roughness, RA for biopolymer film with ratio of 97:3 resulted in higher values. Also it was found that the surface of biopolymer films were hydrophilic after the contact angle was less than 90°. This can be concluded that the biopolymer based on alginate/chitosan is a promising candidate for wound healing materials particularly with good surface properties for faster healing process at the wound areas.
Mechanical Properties of Bioactive Glass Fabricated Using Natural Resources Materials
Authors: Fakhruddin Ahmad Kamil , Mohamad Hasmaliza
Published: September 2020

Bioactive glass use silica (SiO2), calcium carbonate (CaCO3), sodium carbonate (Na2CO3), phosphorus pentoxide (P2O5) as raw materials. In this work, bioactive glass (BG); 45S5 bioactive glass was synthesized using natural resources materials; rice husk ash (RHA) as silica (SiO2) source and seashell (SS) as calcium carbonate (CaCO3) source through melt derived method. All raw materials were melted at 1400 °C and water quenched. The glass frit obtained was milled and sieved then analyzed using X-ray diffraction (XRD), Fourier Transform Infrared spectroscope (FTIR) and Scanning Electron Microscope (SEM). The mechanical properties 45S5 BG pellet was observed through diametral tensile stress (DTS). The XRD and FTIR pattern for all sample synthesized using natural resources raw materials show similar pattern with control sample 45S5 synthesis using pure raw materials. The mechanical properties for all samples also have not significantly different with control samples
Characterization of NiTi Shape Memory Alloy Sintered at Different Temperatures in Reducing Environment
Authors: Zaki Hafizah Hanim Mohd , Mohd Sobri Nur Azemuzahir , Abdullah Jamaluddin , Sariffudin Norshahida , Daud Farah Diana Mohd
Published: September 2020

NiTi has received significant interest as medical implant materials due to its shape memory effect behavior apart from its good biocompatibility and mechanical properties. The formidable challenge of obtaining single phase NiTi from elemental powders via solid state is due to oxidation problem of elemental powders and the oxygen atoms dissolve in NiTi matrix as interstitial impurities forming stable oxygen-rich TiNiOx. This may deterioriate the shape memory behavior of NiTi. This research investigates the use of MgH2 in combination with CaH2 as in-situ reducing agent to eliminate oxidation of the specimen during sintering both at lower and higher sintering temperatures. Here, the effect of sintering temperature on phase formation and transformation behavior of NiTi in reducing environment was studied. The phase formation was characterized by using x-ray diffraction (XRD) where the morphology and elemental analysis were characterized by using the scanning electron microscope (SEM) equipped with EDS. The martensitic transformation behavior was analyzed using differential scanning calorimeter (DSC). The use of MgH2 and CaH2 as reducing agent has a significant influence on the phase formation of NiTi synthesized via solid state especially at 930 °C, where almost single phase NiTi was formed with good transformation behavior. This reducing agent creates a conducive environment for the production of single phase NiTi.
Rheological and Fired Properties of Malaysia Clay from Ipoh (Perak) and its Application in Ceramic Tiles
Authors: Chin Chee Lung , Ahmad Zainal Arifin
Published: September 2020

Clay is an important raw material in manufacturing of ceramic products especially ceramic tiles. Local clays are important for demand of local ceramic tile industries especially the advantages in terms of transportation cost. The research work is aimed to provide scientific data on rheological behavior and fired properties of Ipoh clay from Perak, Malaysia and its application in ceramic tiles. The studied clay was characterized by mineralogical analysis and chemical composition to determine the mineralogy of Ipoh clay. Rheological behavior was identified by deflocculant demand, thixotropy and zeta potential. Fired properties were determined by linear fired shrinkage, water absorption, bulk density, apparent porosity and fired colour. The Ipoh clay is considered suitable to be used for wet milling process in manufacturing of ceramic tiles due to highly negatively charge from the outcome of zeta potential. Ipoh clay is considered as dimensional stable with range of linear fired shrinkage of 2.5 to 3.5% from firing temperature from 1000 – 1050 °C. Firing temperature of 1050 °C – 1250 °C shows drastic increase in linear fired shrinkage from about 3.5% to above 10% together with drastic reduction in water absorption from about 19% to 5%. Ipoh clay is considered not suitable to be used in high amount for application in porcelain tiles that need water absorption of almost zero together with low in apparent porosity. However, Ipoh clay has good fired colour, which is suitable for technical polished porcelain tiles.
Role of Alloyed Niobium on the Isothermal Oxidation of Fe-40Ni-24Cr Alloy
Authors: Parimin Noraziana , Hamzah Esah
Published: September 2020

Fe-40Ni-24Cr alloy is the heat-resistant alloy usually use at high temperature service. The alloying elements normally added to the alloy to enhance the resistance to severe oxidation during service. The Fe-40Ni-24Cr alloy was experienced a high temperature oxidation at 700 °C for 500 h exposure time in laboratory air. The discontinuous isothermal oxidation test was carried out at different time intervals to record the weight change of the oxidized alloy throughout the experiment. The oxidized Fe-40Ni-24Cr alloy was characterized in terms of oxidation kinetics, phase analysis by using x-ray diffraction (XRD) technique and oxide surface morphology determination by using scanning electron microscope (SEM) equipped with energy dispersive x-ray (EDX) spectrometer. The oxidation kinetics of oxidized Fe-40Ni-24Cr alloy was exhibited a weight gain trend. The calculation of oxidation rate law was proved that this oxidized Fe-40Ni-24Cr alloy was obeyed parabolic rate law indicating the growth of oxide scales was followed a diffusion-controlled mechanism. The phase analysis of the oxidized Fe-40Ni-24Cr alloy recorded the formation of several oxide phases consists of Cr-rich, Fe-rich, Ti-rich, Nb-rich and spinel oxides structure. These oxides were served as a protective barrier between base metal and environment. The surface morphology of oxide scale after different exposure displayed a continuous oxide layer formed on the alloy surface with evidence of overgrown Nb-rich oxide particle at discrete area on the alloy surface starting from 150 h exposure time.
Relationships between emotional schemas, mindfulness, self-compassion and unconditional self-acceptance on the regulation of psychological needs
Authors: Faustino Bruno , Vasco António Branco , Silva Ana Nunes , Marques Telma
Published: September 2020

Emotional schemas are pervasive mental structures associated with a wide array of psychological symptoms, while mindfulness, self-compassion, and self-acceptance are viewed as adaptive psychological constructs. Psychological needs may be described as the cornerstone of mental health and well-being. However, a study of the relationships between emotional schemas, mindfulness, self-compassion, and self-acceptance with psychological needs was not performed. For this purpose, 250 subjects (M=20.67, SD=4.88, Male=33, Female=217), were evaluated through self-report questionnaires, in a cross-sectional design. Negative correlations were found between emotional schemas, mindfulness, self-compassion, unconditional self-acceptance, and psychological needs. Symptomatology was positively correlated with emotional schemas. Mindfulness, self-compassion, and unconditional self-acceptance predicted the regulation of psychological needs and mediated the relationship between emotional schemas and psychological needs. Emotional schemas may be associated with a tendency for experiential avoidance of internal reality, self-rejection/shame and self-criticism which may impair the regulation of psychological needs. These variables may be targets of integrative case conceptualization and clinical decision making focused on patient’s timings, styles of communication and needs.
Ground states for nonlocal Schrödinger type operators on locally compact abelian groups
Authors: Kochubei Anatoly N. , Kondratiev Yuri
Published: September 2020

We find classes of nonlocal operators of Schrödinger type on a locally compact noncompact Abelian group

\mathfrak G

, for which there exists a ground state. In particular, such a result is obtained for the case where the principal part of our operator generates a recurrent random walk. Explicit conditions for the existence of a ground state are obtained for the case

\mathfrak G =\mathbb Q_p^n

where

\mathbb Q_p

is the field of

p

-adic numbers.