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Corresponding Author
Abdul Aziz Faisal
Institutions
a) Department of metallurgical and materials engineering, Faculty of Engineering, Universitas Indonesia, Kampus UI Depok, Indonesia 16424
*anne[at]metal.ui.ac.id
Abstract
At present, the combination of metal matrices and ceramic reinforcement as composite is popular for creating materials with good mechanical properties. Aluminum is used as a matrix because of its lightweight, ductile, and low melting point. In this paper we discuss the effect of adding silicon nitride reinforcement to AC4B aluminum. Five sample variations were made based on fraction volume percent (1, 3, 5, 7, 10) which were fabricated through stir casting method. In the fabrication process the magnesium element was added to increase the wettability, TiB grain refiner, and modification with strontium element. The samples made got destructive, tensile, impact, and hardness testing to determine the mechanical properties of the composite. Observation of phases, elements, compounds and microstructure was done to see the distribution of reinforcing particles in the aluminum matrix and the estimated phases formed. The results showed that the optimum tensile strength of variable occurred at the addition of 1% volume of silicon nitride with a strength value of 104.94, and the optimum hardness value was at the addition of 3% Si3N4, which was 44.8 HRB. The phases formed in the composite were Mg2Si, Al2Cu, β-Al5FeSi, and π - Al9FeMg3Si5 phases.
Keywords
AC4B; Micro Si3N4; Stir Casting
Topic
Materials Science
Corresponding Author
Fachri Munadi
Institutions
1) Department of Chemical Engineering, University of Indonesia
Jalan Fuad Hasan, Pancoran MAS, Kukusan, Beji, Kota Depok 16424, Indonesia
*Corresponding author: dsupramo[at]che.ui.ac.id
Abstract
Crude oil refineries in Indonesia produce much waste in the vacuum distillation as vacuum residue, but its utilization is still low. As heavy oil residue, vacuum residue contains high aromatics and therefore high carbon which can be utilized as raw material to produce high surface area activated carbon (AC). Such a AC is widely used in the field of gas storage and electric double-layer capacitors (EDLCs). Electric double-layer capacitors (EDLCs) with activated carbon electrodes are known to have higher capacity for energy storage. Vacuum residue containing isotropic aromatics can be pyrolysed to form anisotopic aromatics which has high crystalline content thus increasing mechanical strength of AC. In the present work, vacuum residue was mixed with dehydrated castor oil as conjugated double bond source, then followed by pyrolysis at heating rate of 5°C/min until 450°C and holding time at 450°C for 90 minutes. The amount of dehydrated castor oil added to vacuum residue was varied at 0%, 5%, 10%, and 15% weight of vacuum residue. Castor oil can be obtained from castor oil plants, which are widely grown in Indonesia, by extraction process of castor bean. Dehydration of castor oil used a catalyst of sodium bisulfate to obtain conjugated double bonds. Co-pyrolysis of vacuum residue and addition of conjugated double bonds reduce C/H atomic ratio precursors, from 1.82 to 1.50, 1.48, and 1.45. Product of co-pyrolysis of vacuum residue and dehydrated castor oil was used as a precursor to prepare for activation and carbonization. The activation was conducted by activating the precursor with KOH solution and followed by carbonization at heating rate of 5°C/min until 700°C and holding time at 700°C for 30 minutes. The results show that the addition of castor oil by 0%wt, 5%wt, 10%wt, and 15%wt improved pore surface area from 150.32 m2/g, 236.97, 290.99, and 357.78 m2/g.
Keywords
Mesophase Pitch, Dehydrated Castor Oil, Vacuum Residue, Pyrolysis.
Topic
Materials Science
Corresponding Author
Klodian Dhoska
Institutions
(1) Faculty of Mechanical Engineering, Polytechnic University of Tirana, Mother Teresa No.4
1001 Tirana, Albania
(2) Faculty of Engineering, University of Sultan Ageng Tirtayasa. Jl. Jend Sudirman km. 3
Cilegon Banten 42435 Indonesia
Abstract
Over the last decade, air pollution in the Republic of Albania is in a crucial moment and an actual problem that effect on human health. Many of the problems has been noticed in the industrial cities and urban zones where the number of industries and road transport has grown rapidly. One of the largest environmental impacts comes from landfilled and burning of the waste tires. This problem has made the government to support some companies for building up the recycling industry of the waste tire in Albania. The Recycled Tire Rubber have been used in many fields such as agricultural uses, sport applications, civil engineering, rubber modified asphalt applications etc. Therefore, different parts of the world have used rubber modified asphalts where the benefits were being more widely experienced and recognized. Based on it, our paper will be focused on the asphalt mixtures produced with Recycled Tire Rubber Modified Bitumen-s (RTR-MBs). The analysis of penetration, softening point and Marshall Test will be described in this paper. Our proposal can reduce environmental impact from the waste tires and improving the quality of the road constructions in Albania.
Keywords
Asphalt Application, Recycled Tire Rubber Modified Bitumen, Additives, Quality, Road Construction, Environmental Impact
Topic
Materials Science
Corresponding Author
MUHARAM KEMAL ADAM
Institutions
a) Department of Metallurgical and Materials Engineering, Faculty of Engineering, Universitas Indonesia, Kampus UI, Depok, Indonesia 16424
*anne[at]metal.ui.ac.id
Abstract
Characterization of AC4B/Nano TiC Composite With Volume Fraction Variation of Nano TiC Reinforce by Stir Casting Process has been investigated. Author used aluminium alloy series three, AC4B, which contain silicon and copper as its main alloy. Furthermore, the addition of Nano TiC into AC4B composite can increase the tensile strength, ductility, and toughness of AC4B composite by refining the dendrite structure of the α-Al phase and forming super saturated solid phase, θ (Al2Cu). This research opens the opportunities of aluminum composite material to be used in arms industry, such as bulletproof material. In this study, AC4B/Nano TiC composite were made through stir casting with some variable parameters of Nano TiC reinforce composition of 0.25%, 0.3%, 0.35%, 0.4%, and 0.5% volume fraction to determine the optimum value of the mechanical properties of AC4B/Nano TiC composite. Stir casting process was chosen because it has several advantages, such as easy to use, flexible, and can be used to produce a large number of the products. It is known that AC4B/Nano TiC composite has optimum value of the mechanical properties when Nano TiC composition is 0,3% volume fraction with ultimate tensile strength of 132,31 MPa and the hardness of 55,18 HRB.
Keywords
AC4B Composite; Nano TiC; Stir Casting
Topic
Materials Science
Corresponding Author
DNK Putra Negara
Institutions
(a) Mechanical Engineering Department of Udayana University, Street of Bukit Jimbaran, Badung, Bali, Indonesia
(b) PPPTMGB “Lemigas”, Jl. Ciledug Raya Kav. 109, Jakarta Selatan, 12230
*E-mail: devputranegara[at]gmail.com
Abstract
Activated carbon is a multipurpose material due to its unique characteristics such as high surface area and pore volume. This paper concerns to develop and characterize of activated carbon from lignocellulosic material, particularly from swat bamboo (Gigantocholoa verticillata). Activated carbons were manufactured under different carbonization temperatures (550, 650, and 750OC) and activation durations (1.5 and 2 hours). Characterizations conducted include proximate and proximate analyses and nitrogen adsorption isotherm test in order to know the proximate and elemental composition and the structural characteristics (pore volume, surface area, pore diameter, and pore size distribution), respectively. The results show that activated carbon that activated at a temperature of 750 OC over 1.5 hours obtain the optimal characteristics. This activated carbon had highest surface area (SBET), pore volume (Vp) and nitrogen adsorption capacity of 135.30 m2/g, 0.138 cm3/g, and 95.776 cm3/g, respectively, with an average pore diameter of 2.053 nm and fix carbon and C contents of (75.26%) and C (76.79%) respectively. Its pore size distribution is monomodal and most of the adsorption occurred at pore size in the range of 0.795–10.486 nm and the highest adsorption (0.056 cm3/g/nm) occurred at a pore size of 1.516 nm.
Keywords
Lignocellulosic material, activated carbon, adsorption isotherm, pore size
Topic
Materials Science
Corresponding Author
Agus Dwi Anggono
Institutions
Mechanical Engineering Department, Universitas Muhammadiyah Surakarta
Abstract
In Indonesia, plastic waste production was at the second rank in domestic waste. It was produced around 5.4 million tons per year. It became national issues, due to Indonesia was the second biggest country after China that poisoning the sea with plastic. The objectives of the study are to develop biodegradable plastic composite and to investigate the mechanical characteristic and water absorption. It was made from polypropylene (PP) mixed with corn stalks powder. In this study, the weight fraction of polypropylene and powder was varied as 95%: 5%; 90%: 10%; 85%: 15%. For the water absorption test, the specimens were soaked in the water for 1, 7, and 14 days. The highest value of the tensile test was delivered from a specimen of 95%:5% weight fraction. The tensile test of the soak specimen for 0, 1, 7, 14 days was obtained 17,41 MPa, 16,94 MPa, 16,11 MPa, 13,51 MPa respectively. The strain was 1.07%, 1.19%, 1.01%, 0.87%. The modulus of elasticity was 1686,74 MPa, 1500,42 MPa, 1712,1 MPa, 1558,49 MPa. By adding the powder to the plastic, it was able to absorb water. The water absorption after 1, 7, and 14 days of water soak was 0.607%, 1.468%, and 4.651% respectively. The specimen of biodegradable plastic composites with a 95%: 5% ratio have compatible characteristics with commercial plastics and can be degraded easier.
Keywords
composite, biodegradable plastic, polypropylene, corn stalks powder
Topic
Materials Science
Corresponding Author
Yus Rama Denny
Institutions
1 Department of Physics Education, Faculty of Teacher Training and Education, University of Sultan Ageng Tirtayasa, Jl. Ciwaru Raya No. 25, Cipare, Serang, Banten 42117, Indonesia
2 Department of Metallurgical Engineering, Faculty of Engineering, University of Sultan Ageng Tirtayasa, Jl. Jenderal Sudirman Km 3 Cilegon, Banten 42435, Indonesia
Abstract
The results of the studies carried out on the effect of varying the precursor concentration and annealed substrate on the crystal structure, electronic and optical properties of ZnO thin film synthesized are presented in this article. An aqueous solution of Acid Nitrite was used as precursors and its concentration was varied from 0.1 M to 0.4 M. The ZnO thin film was deposited on the glass substrate by Spray Pyrolysis Deposition and annealed with different temperature from 300 oC to 600 oC. The crystal structure, electronic and optical properties were investigated by x-ray diffraction and UV-Spectrometer. Whereas, the surface morphology and the grain size of the thin films were investigated by SEM. Particles with sizes ranging between 21.83 to 43.67 nm were synthesized by varying the precursor concentrations and varying annealed substrate temperature. It showed that concentration of the precursor had slightly impact to the particle size. However, the increase in particle size with increasing annealed temperature is found to be gradual. Particle sizes calculated from the X Ray diffraction studies of the samples using Scherrer formula were found to agree fairly well with those estimated from band gap values. The average transparent of all thin film was more than 75%. The band gap of the ZnO thin films were estimated by Tauc Plot Relation. It showed that the band gap values were increased with the increasing of precursor concentration due to Burstein-Moss Effect. In addition, the decrease in band gap values was found with increasing annealed temperature. Our results demonstrated that the varying precursor concentration and annealed substrate temperature can enhance the structure, electronic and the optical properties of ZnO thin films.
Keywords
ZnO thin film; Spray Pyrolysis; Electronic properties; optical properties; Precusor Concentration; Substrate Temperature
Topic
Materials Science
Corresponding Author
Febriyati Puspasari
Institutions
Department of Chemical Engineering, Faculty Technology of Industry, Institut Teknologi Sepuluh Nopember Surabaya, Jl. Arief Rahman Hakim, Surabaya 60111, Indonesia
*onramus[at]chem-eng.its.ac.id
Abstract
Cassava starch is one of the biopolymers which can be degraded to many useful products such as reducing sugar, non-reducing sugar and modified starch. However, it has a solid granule structure that can inhibit its degradation process. High shear mixing (HSM) is a well-known method for dissolving biopolymers. Shear effect of HSM created by narrow slit between rotor and stator which can be increased by the increase of rotational speed. By increasing its shear effect, HSM is able to cut the glycosidic bond of starch to produce reducing sugar. Therefore, this study aims to study the effect of high shear rate to granule structure and reducing sugar product. The HSM process was carried out on the suspension of cassava starch with concentration of 1/20 (g/mL) for 15 min at various stirring speeds (5000-15000 RPM). Products produced from the process are separated between solid and liquid for analysis. Solid products were analyzed using Scanning Electron Microscopy (SEM), Particle Size Analysis (PSA), and Viscometer Ubbelohde. While liquid products were analyzed using UV-Vis Spectrophotometry with the DNS method. Based on the experimental results, HSM produced reducing sugar up to 0.1972 mg/mL. Granule breakage was also observed by SEM and increasing of nanoscale granule.
Keywords
Cassava Starch; Degradation; High Shear Mixing; Homogenization; Reducing Sugar
Topic
Materials Science
Corresponding Author
Muhammad Rifai
Institutions
a) Center of Science and Technology for Advanced Material, National Nuclear Energy Agency
Kawasan Puspiptek, Serpong, Tangerang 15314, Indonesia.
*iamrifai[at]yahoo.com
b) Department of Mechanical Engineering, Doshisha University, 1-3 Tatara Miyakodani, Kyotanabe, Kyoto 610-0394, Japan.
Abstract
Corrosion fatigue properties of ultrafine grained (UFG) Fe-20%Cr steel by equal channel angular pressing (ECAP) was investigated in term of grain refinement and stored energy. Iron chromium alloy as referred to as stainless-steel has been wide used as a material for cardiovascular stents, orthopedic and different implants used as biomedical application because of the plasticity and corrosion resistance. The improvement of strength was related to the grain refinement by ECAP process, however the decreasing of ductility is occurred. Effect of the grain boundary status can be examined by comparison between equilibrium dan non-equilibrium by annealing at 698 K. Under annealing temperature of 698 K, due to the recovery stage, there was a little difference in microstructure from the four passes ECAP. The corrosion fatigue life of the ECAP processed and the post-ECAP annealed sample was analyzed. Two mechanisms for crack propagation have been well recognized for stainless steel. One is slipping step dissolution mode. In this model, the slip step formed by active dislocation at a crack tip is anodic dissolution reaction, so that crack tip advance to further distance. The other is stress adsorption mechanism. The corrosion fatigue cracks initiation and cracks propagation process of iron-chromium alloy can be characterized by corrosion pits and intergranular fracture, respectively.
Keywords
Iron chromium; grain refinement; ECAP; Corrosion fatigue
Topic
Materials Science
Corresponding Author
Amalia Sholehah
Institutions
1 Advanced Material and Tomography Laboratory, Universitas Sultan Ageng Tirtayasa, Jl. Jenderal Sudirman Km 3 Cilegon, Banten – Indonesia 42435
2 Department of Metallurgical Engineering, Faculty of Engineering, Universitas Sultan Ageng Tirtayasa, Jl. Jenderal Sudirman Km 3 Cilegon, Banten – Indonesia 42435
3 Center of Non-Destructive Testing and Process Imaging, CTech Laboratories, EdWar Technology, Jl. Sutera Kavling Spektra Blok 23 BC No 10 – 12, Tangerang Selatan, Banten – Indonesia 15325
4 Department of Metallurgical and Materials Engineering, Faculty of Engineering, Universitas Indonesia, Kampus Baru Universitas Indonesia, Depok, Jawa Barat – Indonesia 16424
5 Departement of Engineering Physics, Faculty of Industrial Technology, Institut Teknologi Bandung, Jl. Ganesha No. 10, Bandung, Jawa Barat – Indonesia 41032
Abstract
Capacitive sensor works based on capacitive methods and serves to detect changes in the composition of dielectric materials by determining the capacitance value and dielectric constant. This type of sensor has advantages in convenient manufacturing process, a simple working mechanism, as well as extensive applications in various fields. In this study, capacitive sensors were used to characterize the electrical properties of materials that have several structures. The dielectric material samples used are bulk ZnO with particle (spherical) structure, ZnO synthesized by chemical bath deposition method (CBD) which has a rod structure, and synthetic ZnO results through a vapor phase method with tetrapod structure. The sensors were made by a parallel plate method using two copper plates as capacitors. The sensors were designed in 2x2 cm and 2x4 cm size, with the distance between the electrodes being 1 and 2 mm. The results showed that capacitive sensors proved to be able to distinguish capacitance values and electrical permittivity of ZnO with different structures. From the experiment, it was known that ZnO with a rod structure synthesized through the CBD method gave the highest capacitance and electrical permittivity values compared to other ZnO samples.
Keywords
ZnO, capacitive sensor, capacitance, permitivity
Topic
Materials Science
Corresponding Author
Ni Luh Gede Ratna Juliasih
Institutions
1 Chemistry Department,
Faculty of Mathematics and Natural Sciences,
University of Lampung, Jl. Sumantri Brojonegoro No. 1 Bandar Lampung 35145, Indonesia.
* ratnagede.juliasih[at]gmail.com
2 Biochemistry Division, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40231, Indonesia.
Abstract
Diatoms are unicellular photosynthetic microalgae, which dispersed in marine and freshwater environments. More than 200 diatom genus with around 100,000 species found in nature, each with different morphologies and dimensions. Their cell walls are composed of biosilica and exhibit species-specific nanoporous to microporous and macroporous patterning which is a promising renewable material for various applications, such as in catalysis, drugdelivery systems, sensors, and Biophotonics, due to the high surface area, mechanical resistance, unique optical features, and biocompatibility. In this study, biosilica of tropical marine diatom C. striata was used as a material for protein purification. The frustule of C. striata was washed with an acid solution and dried in oven. Remaining organic compounds were removed via calcination in a furnace. The biosilica was modified using 3-Mercaptopropylmethyl-dimethoxysilane (MPTS) and the obtained material was characterized using FTIR and SEM_EDX. The binding test capacity was conducted to evaluate the modified biosilica. The protein binding capacity of the modified biosilica was 14520 µg/mL.
Keywords
microalgae, diatom, Cyclotella striata, biosilica, protein purification
Topic
Materials Science
Corresponding Author
ERLINA YUSTANTI
Institutions
(a) Department of Metallurgical Engineering, Faculty of Engineering, Sultan Ageng Tirtayasa University, Jl. Jenderal Sudirman KM.03 Cilegon-Banten 42435, Indonesia
(b) Research Center for Metallurgy and Material, Indonesian Institute of Sciences (LIPI), Kawasan Puspiptek Serpong, Tangerang Selatan 15314, Indonesia
(c) Research Center for Physics–Indonesian Institute of Sciences (LIPI), Puspiptek Serpong, Tangerang Selatan 15314, Indonesia
Abstract
Fluorine-doped tin oxide is a thin layer of transparent conductive oxide, which has a function as a semiconductor. Fabrication of fluorine tin oxide from this research was expected to replace indium-doped tin oxide. Indium-doped tin oxide function as a commercial transparent conductive oxide. The raw material of indium was limited, so the price is higher than fluorine. The material used are Indonesia local tin (IV) Chloride, ammonium fluoride, and methanol. Conductive liquids has made by the sol - gel method. Sol gel liquids doped with ammonium fluoride to make a high conductivity. The transmittance value at the 1, 2, 3, 4, and 5 minutes deposition time were respectively 69.7; 43.6; 14.4; 14.1 and 34.7%. In this research, spin coating method under 3000 RPM and annealing temperature at 300oC. The results of the experiment shows, increased deposition time, make the thickness of the layer increased while resistivity and transmittance decreased. The optimum parameter for glass conductivity fabrication were obtained at 4 minutes time deposition, substrate temperature at 300 oC has a resistivity of 125 k Ω, transmittance 14.1% and bandgap energy 2.48 eV.
Keywords
fluorine-doped tin oxide, stannic (IV) chloride, sol - gel, spin coating.
Topic
Materials Science
Corresponding Author
Sugeng Slamet
Institutions
1 Department of Mechanical and Industrial Engineering, Universitas Gadjah Mada, Yogyakarta, Indonesia
2 Mechanical Engineering, Universitas Muria Kudus, Jl. Gondangmanis PO.Box 53, Bae Kudus, Indonesia
3 Center for Innovation of Medical Equipments and Devices/CIMEDs, Department of Mechanical and Industrial Engineering, Faculty of Engineering, Universitas Gadjah Mada, Indonesia
Abstract
Casting and forging is a method of formation to produce gamelan instruments. This study aims to determine the effect of forging deformation on the as-cast gamelan bar to changes in the microstructure, hardness, density, porosity, and acoustical properties of the gamelan instrument. The research material was tin bronze Cu-25wt.%Sn. The casting process uses a sand casting method with a pouring temperature of 1100 °C. The forging deformation process was done by reheating the as-cast gamelan bar at a temperature of 600 °C. The thickness of the as-cast gamelan bar is reduced by 30% after the forging deformation process. The observations on the as-cast gamelan bar show coarse microstructure with large grains, inclusions, and increased porosity. The forged gamelan bar shows finer microstructure, elongated grain, α lamellar, α phase like a plate, and decreased porosity. The hardness of forged gamelan bar increased by an average of 30.3% VHN, density increased by 9,56% and porosity decreased by 95% compared to the as-cast gamelan bar. Acoustic properties show an increase in the natural frequency between the as-cast gamelan bar and the forged gamelan bar are 712.5 Hz and 1058 Hz.
Keywords
tin bronze, casting, gamelan bar, forging, acoustic
Topic
Materials Science
Corresponding Author
Dani Gustaman Syarif
Institutions
Center for Applied Nuclear Science and Technology-BATAN Jl. Tamansari 71, Bandung 40132, Indonesia.
Corresponding author e-mail: danigus[at]batan.go.id
Abstract
Al2O3 nanoparticles have been synthesized by the hydrothermal method for heat transfer nanofluid as an alternative to new cooling fluid. Nanoparticles were synthesized using AlCl3 as a precursor and urea was used as a supporting agent. The hydrothermal process was carried out at 150oC for 17 hours. The hydrothermal product was dried and then calcined at 600oC for 1 hour. The resulting Al2O3 nanoparticles were analyzed using XRD, FTIR, and TEM. Nanofluids were prepared from these nanoparticles by dispersing them into water as a base fluid. Nanofluid characterization was carried out through Critical Heat Flux (CHF) measurements. According to the XRD data, the Al2O3 nanoparticles produced were gamma alumina with a crystallite size of 4.9 nm. FTIR data shows the presence of OH groups on the surface of the nanoparticles. Al2O3 nanofluids made were known to be stable with an average zeta potential of 50 mV. Compared to water, CHF enhancement of this nanofluid increased by 80%.
Keywords
Hydrothermal, Al2O3, nanofluid, Critical Heat Flux, heat transfer
Topic
Materials Science
Corresponding Author
Henry Wicaksana
Institutions
Departement of Chemical Engineering, Faculty Technology of Industry, Institut Teknologi Sepuluh Nopember Surabaya, Jl. Arief Rahman Hakim, Surabaya 60111, Indonesia
*onramus[at]chem-eng.its.ac.id
Abstract
In petroleum refining processes, such as naphtha hydrotreater (NHT) unit, catalysts are important components to improve the yield of high-quality product. These catalysts are susceptible to inactivation caused by adsorption of sulphur (S) and by metals impurities, such as iron (Fe) and arsenic (As) from the process in a certain time. But the replacement of deactivated catalyst requires a large cost, so the regeneration of catalysts can be an alternative to reduce these costs. And ultrasound is an effective method for regenerating catalysts because the operating conditions and solvents are more environmentally friendly. The effect of ultrasound temperature and presence of citric acid on impurities removal of spent catalyst NiMo was investigated in this study. The mixture of the spent catalyst and 1% citric acid (1/20 (w/v)) was treated by ultrasound at 20% amplitude, 20 minutes and various temperature (30–70°C). After process, solid product was analyzed using Scanning Electron Microscopy (SEM) and X-Ray Fluorescence (XRF). The liquid product was analyzed with Atomic Absorption Spectroscopy (AAS). The content of S was decreased after ultrasound (from 17.3% to 3.8%). The optimum condition was achieved at 50°C and 20 min. Based on AAS analysis which showed Fe composition 73,20 ppm.
Keywords
Citric acid, Deactivation, Regeneration, Spent catalyst, Ultrasound
Topic
Materials Science
Corresponding Author
Muhammad Rifai
Institutions
a) Center for Science and Advanced Material Technology, BATAN, Serpong, Indonesia
*iamrifai[at]yahoo.com
b) Center for Nuclear Fuel Technology, BATAN, Serpong, Indonesia
3Synchrotron Light Research Institute (SLRI), Thailand
Abstract
Zirconium-based materials have attracted extended analysis interest because of their high structural practicality, excellent chemical sturdiness, and intractableness. ZrO2 is additionally wide identified to be used as a surrogate for learning the mechanism of UO2 kernel fabrication of High-Temperature Reactor (HTR) fuels. ZrO2 has similar properties to UO2 system in such a way that microbeads are of paramount importance, especially in the case of such nuclear stimuli-responsive systems. This beads stability will be strongly correlated to the precursor composition and the steps of the synthesis process. One of the simple synthesis processes of ZrO2 microbeads is by gelation process, which could be carried out by internal gelation or external gelation. This article will discuss the synthesis result of ZrO2 microbeads system using external gelation process to understand the gelation process with the emphasis will be given to the interaction of PVA-THFA host–ZrO2 guest systems. FTIR and thermal data were thoroughly explored to derive the mechanism during the gelation process concerning conventional gels in describing general aspects of gel formation.
Keywords
Zirconium; HTR, Surrogate; Gel Formation; Morphology
Topic
Materials Science
Corresponding Author
Ferriawan Yudhanto
Institutions
Department of Mechanical and Industrial Engineering, Faculty of Engineering, Universitas Gadjah Mada, Jl. Grafika No.2 Yogyakarta 55281, Indonesia
*jamasri[at]ugm.ac.id
Abstract
A method using a combination of acid hydrolysis and ultrasonic homogenize were developed to obtain the CNF (cellulose nanofibers) from agave cantala fibers. Acid hydrolysis method was success produces the CNF with a diameter around of 45-50 nm, which investigated by transmission electron microscopy (TEM). PVA (polyvinyl alcohol) nanocomposites were prepared by solution casting technique. Physical properties such as x-ray diffraction (XRD), fourier transform infrared (FTIR) shows highly crystalline of cellulose fibers. It caused by the removal of impurities which covered the fibers such as hemicellulose and lignin. The homogenize mixing method with magnetic stirrer 350 RPM, at temperature of 50oC, for 30 minutes followed by ultrasonic homogenizer has been causing CNF well distributed in the PVA matrix. The effect addition of CNF 5 wt % colloidal in PVA as reinforcement increases the mechanical properties of CNF/PVA nanocomposite. Tensile stress and elongation at break of CNF/PVA nanocomposite were increased by 70% and 137%.
Keywords
polyvinyl alcohol (PVA), cellulose nanofibers (CNF), nanocomposite film
Topic
Materials Science
Corresponding Author
Rahman Faiz Suwandana
Institutions
a) Department of Metallurgical Engineering, Universitas Sultan Ageng Tirtayasa, Jl. Jenderal Sudirman Km 3 Cilegon, Banten 42435 Indonesia
*s.rahmanfaiz[at]untirta.ac.id
b) Institute of Atomic and Molecular Sciences, Academia Sinica, No.1 Sec.4 Roosevelt Road Taipei 10617, Taiwan
c) Department of Physics, National Taiwan University, No.1 Sec.4 Roosevelt Road Taipei 10617, Taiwan
Abstract
The assembly of graphene and other two-dimensional materials into artificial crystals termed van-der-Waals stacks has great potential to produce new materials without precedence in nature and develop novel electronic devices To reliably assemble 2D materials into such structures, however, a better understanding of the transfer process is required. Here we report a quantitative approach to examining the adhesion behavior during viscoelastic stamping of 2D materials. By measuring the adhesion of graphene to different carrier substrates and varying the peeling speed we have identified the range of adhesion of samples. The result shows that the adhesion occurs between graphene-graphene and graphene-SiO2 substrate have a higher value than the ability of PDMS stamp to pick up. A surface modification and an alternative substrate are needed to make the adhesion lower. With proper improvement, this work can be an option to realize an effective fabrication method of a two-dimensional heterostructure device.
Keywords
PDMS stamp, graphene, viscoelasticity
Topic
Materials Science
Corresponding Author
Mikhail Vyacheslavovich Dolgopolov
Institutions
a) Samara University
b) Samara Polytech, Higher Mathematics Department
&
* TP A&ST
mikhaildolgopolov68[at]gmail.com
Abstract
The endotaxia is the process of growth of one crystal structure inside the volume of another. In this case we are talking about the formation of a film of silicon carbide in a silicon substrate. A silicon substrate is placed in the gas chamber. The sample is exposed to the stream of methane gas CH4 at temperature of 1360 - 1380 °C and at normal pressure. Moreover, gas contains both the stable carbon isotope C12 and the radioactive carbon isotope C14, and hydrogen H2 in the gas acts as a carrier of carbon. The process lasts up for 1 hour, during which methane molecules chemically react with sili-con atoms, forming silicon carbide and hydrogen: СН4 + Si → SiC + 2H2. As a result, a silicon carbide SiC film grows in the surface of the sample, and the hydrogen formed dur-ing the reaction leaves the sample and is of no further interest. As a result of the chemical reaction, the crystal lattice of the sample changes and, due to the different parameters of the Si and SiC lattices, defects are formed. The defects in the crystal lattice are various stable violations of the translational symmetry of a crystal. Such defects represent an empty lattice site, and thus are a so-called vacancy for other atoms. In fact, at temperatures above absolute zero, in a solid some of the lattice sites will always be empty, which means that vacancies in a solid will always exist. Carbon atoms, which are already part of the structure, can undergo self-diffusion and diffuse into the interior. What is more, an interstitial diffusion mechanism is distinguished, when an impurity atom moves from one internode to an empty neighboring one, and a vacancy mechanism, when an atom moves from one lattice site to the site where the vacancy is located. We consider a physical model that allows one to describe diffusion in a solid, which takes into account the vacancy mechanism of motion of impurity atoms, i.e. substitution mechanism.
Keywords
SOLID-PHASE DIFFUSION, BETA SOURCE
Topic
Materials Science
Corresponding Author
Callista Fatima Larasati
Institutions
(1) Department of Mechanical Engineering, Faculty of Engineering, Universitas Indonesia, Depok, 16424, Indonesia
(2) Department of Metallurgy and Material Engineering, Faculty of Engineering, Universitas Indonesia, Depok, 16424, Indonesia
(a)sugeng[at]eng.ui.ac.id, (b)callista.fatima[at]ui.ac.id, (c)nurul.ilmaniar[at]ui.ac.id, (d)suharno[at]metal.ui.ac.id
Abstract
Osseointegration is a process consisting of the formation of bone tissue on the implant surface, so that the osseointegration process occurs, a surface with surface roughness (Ra) is required in isotropic microtopography with a size of 1-100 nm. The plasma treatment can be done to reach the Ra parameter. This study aims to discuss the treatment of Plasma Electrolytic Process (PEP) with the principle of physiochemical erosion using electrolytic cells on Ti-6Al-4V alloy implants, to form a plasma layer in the form of spark discharge and Vapour Gas Envelope (VGE). Samples made of Ti-6Al-4V are tested with several parameters including different electrolytes and different applied voltages are investigated, and the results of the formation of VGE which influences the surface characterization are evaluated. The results show that the process of PeP with electrolyte consist of 50% H3PO4 + 10% NaClO4 + 1% HF and 10% ethylene glycol + 2% NH4F at a voltage of 90-130 V produces VGE and non- homogeneous spark discharge resulting in a surface with microporous structures with increasing surface roughness and micro-hardness indicating the formation of an oxide layer.
Keywords
Plasma Electrolysis Process; Surface Roughness; Ti-6Al-4V Implant; Osseointegration
Topic
Materials Science
Corresponding Author
Gatot Trimulyadi Rekso
Institutions
Center for Application of Isotopes and Radiation- National Nuclear Energy Agency, 49 Lebak Bulus Raya Street , South Jakarta, Indonesia
Corresponding author; e-mail; gatot2811[at]yahoo.com, Fax: +62-21-.7513270
Abstract
Abstract. Colloidal Silver Nanoparticles were synthesized by Gamma ray irradiation in aqueous lactic acid solution containing chitosan as stabilizer. The aim of this research is to know the effect of irradiation dose and concentration of chitosan in the formation of Nano-silver. Silver Nitrate of 2 mM is dissolve in the chitosan solution. The effect of chitosan concentration which varied 0,.3%, 0. 5%, and 0. 7%(b/v) were irradiated with gamma ray at dose of 5, 10 and 15 kGy. The formed of silver Nano were identified using UV –Vis spectrophotometer, particle size analyzer (PSA) and FTIR. The result shows, the concentration of chitosan (0.3 – 0,7%) in the irradiated solution also considerably affected the silver Nano particles size which decreased with increasing of irradiation dose. Due to the unique features of the processing procedures, thus Co-60 ray irradiation has been considered as a suitable method for synthesis of colloidal silver nanoparticles.
Keywords
Keywords : Nano particle, irradiation, nano silver, chitosan, lactic acid
Topic
Materials Science
Corresponding Author
Tuti Nur Fitri
Institutions
University of Indonesia
Abstract
Aluminum with a composition of 7-10% Silicone (Si), 2-4% Copper (Cu) was a matrix used with the addition variations of nano-SiC reinforcement particle 0.25; 0.3; 0.4% Vf with the intention of fabricate bullet-proof materials that have high toughness, impact resistance and good strength. In this research, composite was fabricated by stir casting method possessed superior properties due to an effective bonding between matrix and reinforcement particles. In addition to of nano-SiC as a reinforcement particle also followed by the addition of 5 %wt Magnesium (Mg) as the wetting agent, 0.04 %wt Stronsium (Sr) as the modifier, and 0.15 %wt Al-5Ti-1B as the grain reinforcement. The fabricated composite specimens were subjected to various tests to determine the mechanical properties such as density, porosity, hardness, tensile strength, impact, and ballistic testing. The results were compared with basic matrix alloy. Furthermore, the uses of Optical Microscope (OM), Scanning Electron Microscope (SEM), Dispersive X-Ray Spectroscopy (EDX), dan X-Ray Diffraction (XRD) analyses were carried out to analyze the dispersion of the reinforced particles in the selected matrix alloy.
Keywords
Aluminum composites, Nano SiC, AC4B, bulletproof materials, stir casting
Topic
Materials Science
Corresponding Author
Davino Aditya Dwinanda
Institutions
Department of Metallurgical and Materials Engineering, Faculty of Engineering
Universitas Indonesia, Kampus Baru UI Depok 16424, Indonesia.
*donanta.dhaneswara[at]ui.ac.id
Abstract
Refractory coating is widely used in metal casting process to protect the mold from direct contact with molten metal. This coating also could improve the surface quality of casting product. Zircon is common materials that used as filler, but the materials cost is quite high. Therefore, alternative material is needed to make partial substitution of the filler. Silica Fused can be considered as filler because it has good refractoriness. This study aims to determine silica fused is reliable as an alternative to substitute zircon filler. The samples were made with 16%, 18%, and 20% silica fused addition and different treatment which were heated and non-heated drying. Particle size and distributions of the filler were analyzed using Particle Size Analysis. Viscosity measurement also has been done to analyze rheological characteristics of coating slurry. The surface morphology of dried coating was taken using Scanning Electrom Microscope. The quality of coating was determined from the thermal stability of the coating that was analyzed using Differential Thermal Analysis. The result shows thar silica fused is reliable as an alternative material for filler partial substitution.
Keywords
Silica Fused, Zircon, Refractory Coating
Topic
Materials Science
Corresponding Author
Nurul Ilmaniar
Institutions
University of Indonesia
(a) Department of Metallurgical and Materials Engineering, Faculty of Engineering, Universitas Indonesia, Beji, Depok, 16424, Indonesia
*sugeng[at]eng.ui.ac.id
Abstract
Ti-6Al-4V alloy is a common material for orthopedic implant due its high strength-to-weight ratio, corrosion resistance, and biocompatibility. Surgical intervention is required to introduce implant into the body, but it comes with risk of biomaterial associated infection (BAI) or periprosthetic joint infections (PJI). Biomaterial associated infection and periprosthetic joint infections are associated with the presence of bacteria on implant surfaces where they produce biofilm and eventually lead to loosening and implant failure. Treatments for both infections are costly since they require additional surgery to reduce infections and remove biofilm. Surface-modified implants have been introduced with minimum surface roughness to prevent such infections. A key feature is nano-scaled topography with a size of 1-100 nm which minimize bacterial attachment as the initial stage of BAI and PJI. This work aims to study the use Plasma Electrolytic Polishing, an electrochemical machining using high voltage and environmentally friendly electrolyte, to produce low roughness and nano-scaled topography on implant surfaces. Each workpiece is polished in electrolyte comprised of phosphoric acid, sodium perchlorate, and hydrofluoric acid using DC power supply with voltage of 180-400 V. Surface profile of polished workpiece is observed using AFM and SEM whereas the antibacterial properties are tested using the method of disk-diffusion assay.
Keywords
Plasma Electrolytic Polishing, Ti-6Al-4V Implant, Antibacterial properties, Surface roughness, Biofilm inhibition
Topic
Materials Science
Corresponding Author
Rizkijanuar Ramadhan Saputro
Institutions
(a)Department of Mechanical Engineering, Faculty of Engineering, Universitas Indonesia, Kampus UI, Depok, Indonesia 16424
(b)Department of Metallurgical and Materials Engineering, Faculty of Engineering, Universitas Indonesia, Kampus UI, Depok, Indonesia 16424
*sugeng[at]eng.ui.ac.id
Abstract
Titanium and its alloys are standard for orthopedic prosthetic devices, due to their good mechanical properties and biocompatibility. However, bioactivity on the implant surface needs to be improved to achieve an optimal osseointegration process. Metal implants are often coated by hydroxyapatite (HA) because they have a chemical composition and crystal structure similar to apatite in the human skeletal that suitable for bone reconstruction. The focus of this research is on surface treatment designed to promote better biological responses through hydroxyapatite layers. Also combining the acid etching treatment of Ti-6Al-4V and the electrophoretic coating process of the hydroxyapatite to obtain stronger mechanical interlocking interface. HF treatment conducted in various time. Then, coated with nanosized HA through electrophoretic deposition (EPD) at 15V voltage for 10 minutes followed by 800oC heat treatment. Scanning Electron Microscopy and Contour measurements were performed to show the surface topography indicating the formation of surface contours with increasing surface roughness parameters in accordance with the time of the etching process. The contours on the surface of the substrate induce the mechanical interlocking of the surface so that the results of hydroxyapatite deposition optimal at the time of etching 5 minutes.
Keywords
Biomaterials; Chemical Etching; Ti6Al4V; Hydroxyapatite Coating
Topic
Materials Science
Corresponding Author
DNK Putra Negara
Institutions
(a)Mechanical Engineering Department of Udayana University, Street of Bukit Jimbaran, Badung, Bali, Indonesia 80362
*devputranegara[at]gmail.com
Abstract
Machine components such as gear and crankshaft require hard surface and ductile core characteristics. One method to obtained such characteristics is pack carburizing. This research concern to compare the mechanical properties of carburized low carbon steel under different carburizers; GBC (80% goat bone charcoal + 20% BaCO3) and BC (80% bamboo charcoal + 20% BaCO3). The specimens placed in a steel box containing carburizer, loaded into an electric furnace, heated up to a temperature of 950 OC, soaked for 4 hours and quenched in the oil. The hardness and strength of samples were measured by applying of Vickers Hardness Tester and Universal Tensile Machine, respectively. The results of the research showed that hardness, yield strength, tensile strength and modulus elasticity of both carburized low carbon steel increased significantly, however, there was a decrease in elongation. The closer to the core the lower of hardness obtained until at a distance is equal to raw material hardness. The use of carburizer GBC produces carburized steel with higher yield strength (51.75 kg.mm-2), tensile strength (74.58 kg.mm-2), and elongation (5.78 %) than carburizer BC but lower in hardness (558.13 HV1), modulus elasticity (256.79 GPa), and effective case depth (0.33 mm). The mechanical properties of carburized low carbon steels have fulfilled requirements as the material of gear or shaft.
Keywords
Pack carburizing, mechanical properties, energizer, carburizer
Topic
Materials Science
Corresponding Author
Krisna Wisnu Sarwenda
Institutions
Mining Engineering Department, Faculty of engineering Mulawarman University
Abstract
Indonesia has coal reserves of around 166 billion tons of resources and 37 billion tons of reserves. Kalimantan land recorded as the region that holds the largest coal reserves, which is 14.9 billion tons, the largest reserves are in the east Kalimantan region of 7.5 billion tons. One effort to optimize low rank coal is to utilize the low rank coal as raw material for carbonized coal briquettes. Low rank coal research materials are obtained from the new Kampung formation. This resesarch aims to determine the carbonization coal briquette method with a temperature of 600oC in three types of organic binders namely sago flour, tapioca flour and molasses. The carbonization process is carried out for 6 hours. Carbonized coal is crushing at a size of 30 mesh, carbonized coal that has been crushing is mixed with organic binder, then printed with a manual hydraulic system of 15 kg/cm2, then dried. The quality testing of carbonized coal includes parameters of inherent moisture, ash content, volatile matter, fixed carbon and calorific value. The results showed that the carbonized coal briquette produced had the following properties: inherent moisture 11.28% - 14.21%, ash content 6.39% - 8.15%, volatile matter 37.685% - 46.07%, fixed carbon 34.51% - 42.24%, and caloric value 5632.40 cal/gr - 6937.13 cal/gr. Carbonized coal briquette that produce the highest calorific value are obtained from a combination of carbonized coal with tapioca flour, which is 6937.13 cal/gr. The quality of caloric value is fullfiled the coal briquette standard trading for SNI.
Keywords
Low rank coal, carbonization, briquette, caloric value
Topic
Materials Science
Corresponding Author
Daisman Purnomo Bayyu Aji
Institutions
Magister Program of Mechanical Engineering, Universitas Trisakti, Jakarta
Abstract
This study reports a Tool-Narayanaswamy-Moynihan (TNM) simulation on crystallized Zr60Cu25Ni5Al10 amorphous alloy. During a glass transition process, either on heating or cooling, parameters affecting a simulation results remain the same when the physical change during glass transition do not change. Here, we investigated the effect of crystallization fraction occurred on Zr60Cu25Ni5Al10 amorphous alloy after partially crystallized by heating the glassy alloy beyond crystallization temperature. The partial-crystallized samples are for 20 %, 50% and 80% crystals fraction. The results show that the non-linearity parameter, x, increases and the non-exponentiality parameter, β, decreases with higher crystals fraction of the crystallized alloy.
Keywords
Amorphous Alloy; Metallic Glass; Crystallization; Tool-Narayanaswamy-Moynihan; Glass Transition
Topic
Materials Science
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