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Topology Optimization of a Composites Frame Structure considering ply orientation for MALE UAV
Full text linkThis research employs the Finite element method to optimize the frame structure of a Medium Altitude Long Endurance (MALE) Unmanned Aerial Vehicle (UAV). The material used in this study is a unidirectional carbon fiber stacked in a specific sequence. The topology optimization process is conducted to achieve a lightweight structure whilst maintaining its integrity. The design constraint is set to reduce 50% weight and minimize the strain energy. The benchmark phase was performed while considering a previously done study to validate the proposed method. The results of this study have successfully reduced 34% (0.581 kg) weight of frame structure. First failure predicition study using Hashin criterion, shows the first failure occurred in the matrix of Ply-2 at 9000 N
Sensing Properties of ZnO-SWCNT Hybrid Nanostructure Coated on Flexible Substrate for CO2 Gas Detection
Full text linkWe report sensing properties of functionalized single walled carbon nanotubes (f-SWCNTs) deposited on the flexible substrate of silicon (Si) and polyethylene tereptaphalate (PET). Deposition of f-SWCNT on Si rubber and PET surface was conducted by applying different manner of spray coating and dip coating techniques, respectively. Surface modification of f-SWCNT by ZnO nanostructure layer were applied by hydrothermal process.The research study were conducted to know the effect of substrate material and ZnO structure on the f-SWCNT surface which embedded in those flexible polymer substrates. The results reveal that f-SWCNT on Si substrate (f-SWCNT/Si) do not have a good response in gas sensing performance. In meanwhile f-SWCNT on PET substrates (f-SWCNT/PET) is more sensitive about 1.6% with 3s in response. ZnO structure layer modifying the surface structure of f-SWCNT enhance the sensitivity and responsiveness of the sensor with sensitivity of 4.1 % in 2s response after CO2 injection. Effect of bending treatment of the sensor and its stability were further investigated. Morphological surface of f-SWCNT network and crystal structure of ZnO and f-SWCNT were also observed by scanning electron microscope (SEM) and X-ray diffraction, respectivel
COMPARATIVE LIFE CYCLE ASSESSMENT OF EDTA-MODIFIED AND AMINE GRAPTHED SILICA XEROGELS
Full text linkCOMPARATIVE LIFE CYCLE ASSESSMENT OF EDTA-MODIFIED AND AMINE GRAPTHED SILICA XEROGELS. NaI-131 removal from hospital wastewater using various silica xerogel adsorbents has been studied in order to meet the clearance level of radioactive waste. The contaminants emitted from the adsorbent manufacturing may affect the environment and human health. This study aimed to assess and minimize the environmental impacts of two adsorbents: EDTA-modified xerogel silica (EDTA Si-Xe) and Amine grafted silica xerogels (Amine Si-Xe), utilizing life cycle assessment (LCA) with the cradle to gate approach. OpenLCA 1.7 was used to estimate the impact, where background data were acquired from the European reference Life Cycle Database (ELCD) 3.2. The results show the dominant environmental impact resulting from adsorbent manufacturing is climate change. The impact of climate change on EDTA Si-Xe manufacturing and Amine Si-Xe manufacturing is about 0.510 CO2-eq and 0.258 CO2-eq, respectively. EDTA Si-Xe manufacturing performed the best (lower environmental impact) compare to Amine Si-Xe manufacturing. The process stage that contributes dominantly to environmental impact is calcination which gives high environmental impacts to climate change. The percent contribution of calcination to the environmental impact on EDTA Si-Xe manufacturing and Amine Si-Xe manufacturing is about 87% and 66%, respectively. The environmental impacts of the adsorbents manufacturing especially in climate change can be reduced by using Capture Carbon Storage (CCS) technology. Improvement analysis shows EDTA Si-Xe performed lower environmental impact compare to Amine Si-Xe with the value of impact categories lower than without applied CCS technology, especially value of climate change
NANORODS ZnO THIN FILM PERFORMANCE AS TRANSPARENT HEATERS.
Full text linkNANORODS ZnO THIN FILM PERFORMANCE AS TRANSPARENT HEATERS. Transparent heaters have been used for various applications. In this research, a transparent heater made from ZnO nanorods has been successfully fabricated. ZnO nanorods were produced by using the chemical bath deposition method.The results of the XRD investigation showed that the ZnO_0.015 and ZnO_0.025 samples contained three and five ZnO peaks, respectively, with a hexagonal wurtzite crystal structure. The crystallite size increased along with the increase in the solution concentration from 71.198 nm to 82.924 nm. The morphological characterization of the samples using FE-SEM showed that ZnO_0.025 sample had a better surface covarege than ZnO_0.015 sample. The average diameters of ZnO_0.015 and ZnO_0.025 are 127.130 and 146.756 nm, respectively. The transmittance value decreased along with the increase of solution concentration which is from 55% to 53%. The value of the band gap energy decreased as the concentration of the seed solution increased from 3.25 eV to 3.20 eV. The resistivity values of ZnO_0.015 and ZnO_0.025 are 1.126 x 10-4 and 0.824 x 10-4Ωcm, respectively. From these results it appears that ZnO_0.025 sample has a more optimal performance as a transparent heater compared to ZnO_0.015 sample
TEXTURE CHARACTERIZATION OF THE COPPER PRODUCED BY ECAP PROCESS USING NEUTRON DIFFRACTION TECHNIQUE
Full text linkTEXTURE CHARACTERIZATION OF THE COPPER PRODUCED BY ECAP PROCESS USING NEUTRON DIFFRACTION TECHNIQUE. Texture and hardness characterization have been carried out on market copper samples that have gone through the equal channel angular pressing (ECAP) process. Neutron diffraction technique had been used for obtaining an average crystalline texture in a particular volume non destructively to the sample. The ECAP process is carried out once (1 pass) with some parts that have been plastically deformed and some parts that have not been deformed. Crystalline texture and hardness were observed in the deformed and non-deformed parts. Initial characterization was carried out by X-ray diffraction (XRD) followed by measurement of crystal texture using the neutron diffraction technique, while hardness was tested using the Vickers method. Rod-shaped sample with a diameter of 10 mm. Texture observations were performed at the center of the sample with a neutron beam limiting slit of 5x5 mm2 . There was an increase in hardness in the deformed position compared to the undeformed one. The texture that occurs is in the form of fibers with different directions and indexes, sequentially as follows: position 1, [111] of 4.96 m.r.d., position 2, -[111] of 1.86 m.r.d. and position 3 [010] of 2.44 m.r.d. , position 4 orientation is distributed on [011], [013], [115], [235] fibers with a texture index range of 1.07–1.33 m.r.d
Effect of Thermomechanical Treatment Combination on Electrochemical Behavior of Nickel Free-Stainless Steel Fe-10Mn-16Cr-3Mo
Full text linkNickel-free stainless steel has emerged as an implant due to its excellent mechanical and corrosion properties. The toxic effect of Nickel ion released in the conventional SS316L need to be addressed. As one of austenitizing elements used as Nickel substitution, Nitrogen is an important alloying element to improve the strength and resistance to pitting susceptibility. In this research, the Nickel-free Fe-10Mn-16Cr-3Mo stainless steel has been developed. The effect of thermomechanical treatment consists of hot forging, hot rolling, cold rolling, and their combination followed by solution treatment on the electrochemical properties was further investigated. The corrosion resistance of Fe-10Mn-16Cr-3Mo was evaluated by the EIS and polarization test in Hank’s solution at 37℃. A ferrite-austenite duplex structure was identified by microstructural investigation, with indistinct intermetallic phase at homogenized sample. Meanwhile, fully recrystallized grains and twinning structures were formed at thermomechanical samples, indicating in dynamic recovery and dynamic recrystallization. Furthermore, the potentiodynamic parameters demonstrates the protective oxide in all samples. However, sample #5 shows a lower current density, around 0.184 µA/cm2, compared to other samples, indicating more protective passive film. In addition, the corrosion potential of sample #5, around 198 mV leading to higher corrosion resistance up to 0.02894 mmpy
APPLICATION OF RIETVELD ANALYSIS TO THE MULTIPHASE CRYSTAL STRUCTURE Bi1/2K1/2TiO3 USING MOLTEN SALT SYNTHESIS
Full text linkAPPLICATION OF RIETVELD ANALYSIS TO THE MULTIPHASE CRYSTAL STRUCTURE Bi1/2K1/2TiO3 USING MOLTEN SALT SYNTHESIS. Recently, an interesting application development of piezoelectric materials is as part of the tool for in-situ testing of nuclear fuel and the supporting materials in nuclear reactor, as well as sensors for safety systems in the reactor environment itself. One of the piezoelectric materials (lead free) is bismuth potassium titanate Bi1/2K1/2TiO3 (BKT) which is used in this research and has been successfully synthesized using the molten salt method. This method is a simple process that reacts to the base material in a solution of NaCl and KCl salts to produce nanocrystal ceramics powder with good compositional homogeneity and sinterability. The synthesis process has been carried out in two stages, first to produce Bi2Ti4O11 and then to add excess K2CO3 as a base material to produce BKT. The weight ratio between Bi2Ti4O11 and excess K2CO3 was 1:1.5 and 1:2. Structural identification of the synthesized results has been done by Rietveld analysis of the XRD pattern using PAN-Analytical Highscore software. The multiphase of BKT has been obtained by a predominantly tetragonal crystal system, in addition to cubic as second phase. This is indicated by the content of the tetragonal and cubic phases obtained at 64.5 and 36.5% for the ratio 1:1.5 and 80.3 % and 19.7 % for the ratio 1:2, respectively.The addition of excess K2CO3 increases, the content of the tetragonal BKT phase increases. . Besides that, the “a” lattice parameter increases and the “b” lattice parameter decreases, if the K2CO3 content is added. Likewise, the size of the crystallite and microstrain decreases with the in excess K2CO3
PROSES PRODUKSI KOMPOSIT MAGNET DENGAN TEKNIK INJECTION MOULDING
Full text linkPROSES PRODUKSI KOMPOSIT MAGNET DENGAN TEKNIK INJECTION MOULDING. Teknik cetak injeksi untuk komposit magnet merupakan gambaran tentang kesulitan-kesulitan yang dialami selama proses pembuatan. Penelitian mengenai komposit magnet heksaferit dengan bahan baku polimer termoplastik (PP2) dengan serbuk magnet (SrM) yang menghasilkan sifat-sifat bahan yang diinginkan yaitu ringan, elastis, dan harganya murah merupakan suatu inovasi untuk membuat pilot plant ini. Proses produksi ini dirancang dengan menggunakan proses dan peralatan yang sederhana secara teknologi untuk mendapatkan produk yang optimal, serta bahan sisa pencetakan dan steam dapat didaur ulang. Total investasi untuk proses produksi ini diperkirakan sebesar Rp.1,3 Milyar dengan keuntungan bersih per tahunnya sekitar Rp. 241 Juta. Nilai ROI yang diperoleh 72 %, POT selama 2 tahun dan BEP 25 %
HIGH-TEMPERATURE OXIDATION BEHAVIOUR OF Fe11Al BASED ALLOYS
Full text linkHIGH-TEMPERATURE OXIDATION BEHAVIOUR OF Fe11Al BASED ALLOYS. Thermomechanically treated Fe11Al based alloys were isothermally oxidised in air at 900, 1000 and 1100 °C respectively. Their oxidation behaviour was studied using thermogravimetric analyser (TGA), X-ray diffractometer (XRD), and scanning electron microscope (SEM). It was found that the oxide scales formed on alloys studied consisted mainly of α- and θ-Al2O3. Additions of 0.5 wt. % Nb and Mo significantly improved the oxidation resistance of the alloys
THE EFFECT OF REVERSE FLOTATION METHOD ON SILICA SAND AS WATERPROOFING MORTAR
Full text linkTHE EFFECT OF REVERSE FLOTATION METHOD ON SILICA SAND AS WATERPROOFING MORTAR. Waterproof fabrication mortar cement by silica sand using reverse flotation silica (RFS) method was evaluated by waterproof absorption coefficient, compressive strength test, attractive test, and contact angle. RFS is used to replace waterproof agent and aggregate mortar to reduce cost. The aims of this experiment are to know the RFS process, the ratio between waterproof mortar cement with RFS and mortar, to determine performance and characteristic waterproof mortar cement. Methods used are prepared RFS, mortar cement fabrication, and testing (compressive strength, tensile strength, permeability, contact angle, XRF, FTIR, SEM, BET). Variable used are ratio cement/silica sand, concentrations of CaCl2, curing time, oleic acid, and sodium oleate addition. Optimum collector addition is obtained by oleic acid with compress strength 167.65 kg/cm2, tensile strength 0.16 MPa, permeability 4.6 cm, and contact angle 95°. Curing inside water effect and outside temperature give compress strength 167.65 kg/cm2 and 163.24 kg/cm2, permeability curing inside the water and outside temperature are 4.6 cm and 12 cm. Optimum CaCl2 addition is gained at CaCl2 1.8M with compress strength 64.29 kg/cm2, tensile strength 0.15 MPa, permeability 2.4 cm, contact angle 95°. Optimum ratio cement/RFS is 1:1 with compress strength 167.65 kg/cm2, tensile strength 0.16 MPa, permeability 4.6 cm, and contact angle 950