Jusami | Indonesian Journal of Materials Science
Not a member yet
859 research outputs found
Sort by
SANS STUDIES ON THE BOVINE SERUM ALBUMIN DENATURATION IN THE PRESENCE OF SDS
Get PDFThe effect of the presence of sodium dodecyl sulfate (SDS) on the denaturation of bovine serum albumin (BSA) has been studied using 36 m small-angle neutron scattering (SANS) BATAN spectrometer (SMARTer). The neutron scattering data reduction used the Graphical Reduction and Analysis SANS Program (GRASP) software, and the fitting process used the IGOR SANS Analysis software. The denaturation process was identified by observing the changes BSA globular structure. The experimental results showed the addition of SDS at low concentrations (2 mM, 5 mM, 10 mM) into BSA solution at pH 7 do not cause a significant change in the size of the BSA globular structure. The SANS scattering profile of BSA fitted with the triaxial ellipsoid model, a simple shape approach for protein globular structure. The fitting result showed the semi-axis B for BSA in the addition of 2 mM, 5 mM, 10 mM SDS were 33.8 Å, 33.8 Å, and 37.8 Å, respectively. While the semi-axis A and semi-axis C were constant for those three variations at 14.6 Å and 32.2 Å, respectively. In higher addition of SDS, the globular structure of BSA unfolded into flexible cylinder structure with the radius of 14.4 Å and length of 83.5 Å. The denaturation of BSA was clearly showed by the addition of 40 mM SDS. The structure of BSA in this condition fitted to fractal structure with fractal dimension of 1.1, the block radius of 16.7 Å and the correlation length of 42.5 Å. These results indicated that the addition of SDS at low concentrations has not caused the denaturation of BSA. Meanwhile, the addition of SDS at high concentrations made BSA to unfold that lead to the denaturation of BSA
EFFECT OF 5 WT.% WPCB POWDER AS REDUCTANT ON INDONESIAN NICKELIFEROUS ORE PROCESSING
No full textEFFECT OF 5 WT.% WPCB POWDER AS REDUCTANT ON INDONESIAN LIMONITICNICKEL ORE PROCESSING. Waste printed circuit boards (WPCB) are among the most valuable parts of electronic waste with one of the fastest-growing waste streams in the world. The purpose of this study is to investigate the possibility of WPCB powder as an alternative reducing agent for the carbothermic process in nickel lateritic ore processing. WPCB waste was mixed with nickel ore at 1100ÚC in inert atmosphere. In addition, a conventional reductant of coal is also utilized for comparison. Both reductant are varied in concentration of 5 wt% and 15 wt%. Based on thermogravimetric analysis (TGA) and differential thermogravimetric analysis (DTA) investigation, it is observed that there exists a difference between WPCB powder, nickeliferous ore powder, and the mixture in their decomposed levels. The decomposed gasses of WPCB produced by thermal degradation in the TGA instrument are mainly composed of reduction gas, which plays a critical role in reducing the nickeliferous ore. This study shows that WPCB powder performs comparably to sub-bituminous coal in the pyrometallurgical processing of nickel ore, which is proved by X-Ray Diffraction (XRD) test results that the carbothermic products consists of FeNi, magnetite, wustite and fayalite. It can be concluded than WPCB powder has potential to be utilize as an alternative reductant
CHARACTERIZATION OF GOLD NANOPARTICLES FROM CLOVE FLOWER WATER EXTRACT AND ITS ANTIOXIDANT ACTIVITY
Get PDFCHARACTERIZATION OF GOLD NANOPARTICLES FROM CLOVE FLOWER WATER EXTRACT AND ITS ANTIOXIDANT ACTIVITY. Green chemistry is a safe and cost effective method for producing metal nanoparticles, characterize and tested the antioxidant activity of gold nanoparticles (AuNPs). In this research gold nanoparticles were synthesized using HAuCl₄ as the gold precursor and water extract of Syzygium aromaticum (L.) flowers 0.5% as the bioreductor. Characterization of the gold nanoparticles was carried out using UV-Vis spectrophotometer to measure the maximum wavelength, zeta analyzer to determine the particle size, and SEM EDS to investigate the morphology and content of the gold nanoparticles. The antioxidant activity was determined by measuring its free radical scavenging activity using the DPPH method. The research found the AuNPs has a maximum wavelength at 533 nm, and particle size of 73.52 nm. Furthermore, the AuNPs show free radical scavenging activities of up to 70%
ANNEALING TEMPERATURES’ EFFECTS ON MICROSTRUCTURE AND OPTICAL PROPERTIES OF Ba0.95Sr0.05TiO3 FILMS
Get PDFANNEALING TEMPERATURES’ EFFECTS ON MICROSTRUCTURE AND OPTICAL PROPERTIES OF Ba0.95Sr0.05TiO3 FILMS. Ferroelectric materials, one of which is Barium Strontium Titanate (BST), can be applied for photovoltaic. Ferroelectric films function as the P-type semiconductor in the P-N junction. BST (Ba0.95Sr0.05TiO3) films have been deposited on Pt/Si (111) and quartz substrates via the CSD method prepared by spin coater. The films were annealed at various temperatures of 800 °C, 900 °C, and 1000 °C to observe the annealing temperatures' effects on the microstructure and optical properties of the BST films. From the XRD results, the intensity of diffraction peaks gets higher along with the higher annealing temperature. It thus causes the level of crystallization and the crystal size of the Ba0.95Sr0.05TiO3 films to increase. The morphology results reveal that the grains size of the Ba0.95Sr0.05TiO3 films is getting larger with the higher annealing temperature. The optical properties examined in the Ba0.95Sr0.05TiO3 films include absorbance and bandgap energy values. Values of bandgap energy show a decrease with increasing sintering temperature. The smallest bandgap energy of the Ba0.95Sr0.05TiO3 film is achieved at 1000 °C of 3.20 eV. BST films were annealed at temperature 1000 °C attained from this study can be considered as candidate for a photovoltaic ferroelectric material
SYNTHESIS L-LACTIC ACID FROM FERMENTATION OF CASSAVA PULP BY USING TEMPEH INOCULUM
Get PDFSYNTHESIS L-LACTIC ACID FROM FERMENTATION OF CASSAVA PULP BY USING TEMPEH INOCULUM. This study used cassava waste pulp as a fermentation substrate to produce lactic acid using a tempeh inoculum. Tempeh inoculum is a mixed culture of Rhizopus with Rhizopus oligosporus as the primary fungus. Lactic acid is an organic acid most widely used in the food, pharmaceutical, cosmetic and chemical industries. One of the important uses of lactic acid is as a raw material for producing Polylactic Acid (PLA) biopolymers, namely polymers that can decompose naturally in a relatively fast time. The analysis was performed using the Response Surface Methodology (RSM) method and the Box Behnken Design (BBD) experimental design with substrate concentration parameters, inoculum concentration, and incubation time on lactic acid. The fermentation process is carried out using a flask shaker at a temperature of 30 ºC, pH 6.0, and a rotational speed of 150 rpm. The optimum yield for lactic acid is 6.65 g/L. It was acquired at substrate 20 g/L, inoculum concentration 0.30 % (w/v) at an incubation time of 72 hours
