Jurnal ILMU DASAR
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Pore Structure and Morphology Characterizations of Mesoporous ZSM-5 Synthesized at Various Aging Time
Get PDFMesoporous ZSM-5 has been successfully synthesized at various aging time of 6, 12 and 24 h. Mesoporous ZSM-5 was synthesized using cetyltrimethylammonium bromide (CTABr) as a template. Synthesis was carried out hydrothermally with aging and crystallization temperature at 60oC and 150oC. XRD patterns of the resulted material showed diffraction lines at 2θ = 23o and at small angle (2θ < 5o) which is characteristic of the structure of ZSM-5 and the existing of the mesoporous material. It was found that crystallinity of the sample increased at longer aging time. The result of nitrogen gas sorption analysis showed that all samples have pore size about 3,8 nm. The porosity of ZSM-5 decreased with shorter of aging time. ZSM-5 synthesized at 6 h aging time has the highest porosity of 72.57%. Aging time also affected the particle size, the longer the aging time, the smaller the particle size. The particle size was ranging 1.25 – 1.0 μm
The Effects of Oxygen Content, Deposition Rate and Annealing Towards Thin Film of Indium Tin Oxide
Get PDFIndiun tin oxide is one of the materials that has physical properties, rarely seen in other materials. Indium tin oxide properties have the main role in developing the technology of thin film shown through its properties. Therefore, many people study on it since its widespread application to the technological industries. Coating process was carried out by mixing 90 % of In2O3 and 10 % SnO2 on the glass substrate by means of sputtering. During the process of oxygen was added 2.50%, 3.70%, 5,10%, 6.15% and 8.90%. The deposition rate was respectively 4.21 nm/s and 2.25 nm/s. The Indium tin oxide for each condition was annealed at 175oC and 250oC in a vacuum of 10-3 mBarr for 60 minutes. and the micro structure using the x-ray diffraction. Oxygen conten, deposition rate and annealing resulted in the changes of microstructure of indium tin oxide. These changes are mostly resulted from the changes in microstructure such as grain size and lattice constant
CHARACTERIZATION OF SULFONATED POLYSULFONE/BENTONITE HYBRID MEMBRANES
Get PDFSulfonated polysulfone membrane is one of the alternative membranes as replacing Nafion membrane for the fuel cell application. This membrane was prepared by introducing sulfonic group in the polysulfone structure backbone, so that provides the ionic membrane. However, more ionic groups in the SPSF membrane lead to loss mechanical stability. This study aims to prepare the hybrid membrane from SPSF and bentonite. In here, various of bentonite concentrations were used as variable to study water uptake and ion-exchange capacity properties. As the results, increasing bentonite concentrations lead to increase water uptake and ion-exchange capacity. By the functional group analysis, proved that adding bentonite in SPSF did not change structure of SPSF, means that interaction between SPSF and bentonite were physical interactions
Regression for Exploring Rainfall Pattern in Indramayu Regency
Get PDFQuantile regression is an important tool for conditional quantiles estimation of a response Y for a given vector of covariates X. It can be used to measure the effect of covariates not only in the center of a distribution, but also in the upper and lower tails. Regression coefficients for each quantile can be estimated through an objective function which is weighted average absolute errors. Each quantile regression characterizes a particular aspect of a conditional distribution. Thus we can combine different quantile regressions to describe more completely the underlying conditional distribution. The analysis model of quantile regression would be specifically useful when the conditional distribution is not a normal shape, such as an asymmetric distribution or truncated distribution. In general, rainfall in Indramayu regency during 1972-2001 at 23 stations is highly variable in amount across time (month)andspace. So,the first objective of the research is reducing the variability in space using classification of the rainfall stations. The second objective is modelling the variability in time using quantile regression for every cluster of rainfall stations. The result shows that there are two clusters of rainfall stations. The first cluster has higher amount of rainfall than the second cluster. The coefficient of quantile regression for quantile 50 and 75 percent are similar, but for quantile 5 and 90 percent are very different. Exploring pattern of rainfall using quantile regression can detect normal or extreme rainfall that very useful in agricultural
VARIATION OF SOLVENT COMPOSITION EFFECT ON PERFORMANCE AND PHYSICOCHEMICAL PROPERTIES OF CELLULOSE ACETATE MEMBRANE
No full textPerformance Cellulose acetate (CA) were characterized by the variation of solvent composition (acetone and formic acid) with a mole ratio of 5/10; 6/9; 7/8; 8.7; and 9/6 and the addition of additives MSG 6%. Characterization was conducted on the membrane performance (flux, permeability coefficient,% rejection) and physicochemical properties include density test and analysis of membrane structure by FTIR. Membrane solvent variation results, 6/9 has the lowest density values. Results flux, permeability coefficient and the highest rejection is obtained when the composition of the 9/6. FTIR test results showed no difference between the polymer cellulose acetate cellulose acetate membrane solvent variation results
Development System and Reconstruction Method of Translation-Rotation Computed Tomography Using Efficient Sampling
Get PDFTranslation-rotation computed tomography system has been successfully built on this research. The system can be used for the scanning process with sampling method square and hexagonal. It also has been obtained interpolation and reconstruction methods are able to produce reconstruction images fast and accurate. Translation-rotation computed tomography system was built by assembling several instruments that have been made and have existed in the laboratory. Performance of the system was tested by scanning test object. Scanning process has been conducted with the circular test object from metal. Scanning process carried out by performing various of three resolutions, i.e. 31 pixels × 31 pixels, 63 pixels × 63 pixels and 127 pixels × 127 pixels. The sinogram data are square and hexagonal patterns. The sinograms are reconstructed by SCFBP (Summation Convolution Filtered Back Projection) and ART (Algebraic Reconstruction Technique) reconstruction method. Hexagonal sinogram pattern has been interpolated by vertical, horizontal and cross interpolation before reconstructed by ART and SCFBP reconstruction method. Reconstruction image of hexagonal pattern were analyzed by comparing the line profile and its rmsd value of the reconstruction image of square pattern. Performance of the constructed system in the research produced reconstruction image appropriated with objects test. The best interpolation for hexagonal sinogram pattern is cross interpolation. The ART methods produced image reconstruction better than SCFBP reconstruction methods
SCREENING AND IDENTIFICATION ALKALY-CELLULOLYTIC MOLDS FROM RICE STRAW ON COASTAL-FIELD OF WATU ULO JEMBER
Get PDFAbout 28 molds were obtained from rice straw on coastal-field of Watu Ulo Jember, were screened for their cellulolytic activities at pH alkaline. In semiquantitatively screening on CMC and Avicel plate at pH 8 showed that 27 isolates have cellulolytic activities. Based on clearing zone in CMC plate, isolates 7, 9, 14, 19 and 24 have higher cellulase (CMC-ase) activities index at pH alkaline. Further, in quantitatively examination using rice straw in Basic Salt Mandel’s modification medium showed isolate 19 (0,60 U/ml) that identified as Aspergillus terreus have higher FP-ase activity than isolate 7 (0,56 U/ml), 9 (0,55 U/ml), 14 (0,53 U/ml) and 24 (0,56 U/ml)
SYNTHESIS THIN LAYER ZnO-TiO2 PHOTOCATALYSTS SOL GEL METHOD BY USING THE PEG (Polyethylene Glycol) AS SOLVENT
Get PDFThe incorporation of TiO and ZnO material as a composite, to increase the activity of the catalyst. Synthesis of ZnO-TiO2 thin layer made using a sol-gel method with a variation of PEG as a solvent. The purpose of this research was to investigate the structure and morphology of ZnO-TiO2 thin layer on the variation of PEG as a solvent by sol-gel method . Preparation of ZnO sol of the precursor , while the TiO2 sol synthesized by dissolving the anatase TiO2 structure into polyethilen glycol . Sol of ZnO and TiO2 sol do sol mixing to form ZnO–TiO2 after it coated on a glass substrate and then calcined . Products were then characterized by X-ray diffraction to determine the crystal structure and SEM to determine its morphology . The test results show the crystal structure by XRD based difaktogram intensity , the greater the molecular weight of the PEG peak intensity of ZnO-TiO2 showed the lower. While based on morphological examination , it can be seen that the larger molecular weight PEG , ZnO - TiO2 granular greater
On The Existence of Non-Diregular Digraphs of Order Two Less than the Moore Bound
Get PDFA communication network can be modelled as a graph or a directed graph, where each processing element is represented by a vertex and the connection between two processing elements is represented by an edge (or, in case of directed connections, by an arc). When designing a communication network, there are several criteria to be considered. For example, we can require an overall balance of the system. Given that all the processing elements have the same status, the flow of information and exchange of data between processing elements will be on average faster if there is a similar number of interconnections coming in and going out of each processing element, that is, if there is a balance (or regularity) in the network. This means that the in-degree and out-degree of each vertex in a directed graph (digraph) must be regular. In this paper, we present the existence of digraphs which are not diregular (regular out-degree, but not regular in-degree) with the number of vertices two less than the unobtainable upper bound for most values of out-degree and diameter, the so-called Moore bound
Antimicrobial Activity of the Extract and Fraction of Red Betel Leaf (Piper betle Linn.)
Get PDFAntimicrobial activity of ethanolic extract of red betel leaf (Piper betle Linn.), n-hexane fraction and ethyl acetate against Staphylococcus aureus, Escherichia coli and Candida albicans had been carried out. Red betel leaf powder was extracted with 80% ethanol, followed fractionate with n-hexane and ethylacetate. The result was tested in vitro with agar diffusion method using a steel cylinder. Phytochemical screening test was performed to betel leaf powder, while the extract and each fraction were tested with antimicrobial activity in vitro. The thin layer chromatography (TLC) was performed with stationary phase silica gel GF 254 and moving phase of n-hexane: ethyl acetate (8:2), (7:3), (6:4), (5:5) toluene: ethyl acetate (6:4), chloroform: methanol (7:3). Phytochemical screening result indicated the presence of glycosides, triterpenoids/steroids, flavonoids, tannins and anthraquinon. Both of 80% ethanol extract and fractions of red betel leaf (Piper betle Linn.) have antimicrobial activity with Minimum Inhibitory Concentration (MIC) of ethanol extract 80% against Staphylococcus aureus, Escherichia coli and Candida albicans are 2.5%, 2.5%, 10%. The n-hexane fractions were 20%, 15%, 10% and the ethyl acetate fractions are 2.5%, 1%, 2.5%, while the water fraction did not show any antimicrobial effects. The ethanol extract indicated a higher inhibitory effect in Escherichia coli, while the ethyl acetate fraction showed a higher effect on Staphylococcus aureus and Candida albicans. The TLC results showed the presence of terpenoids/steroids, flavonoids, and tannins in ethanol extract, tannin and flavonoid in ethyl acetate, terpenoid/steroids in n-hexane fraction