Journal of Mathematical and Fundamental Sciences
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Influence of TiO2/TS-1 Calcination on Hydroxylation of Phenol
Get PDFTitanium oxide (TiO2) was impregnated on the surface of titanosilicate-1 (TiO2/TS-1) and used as catalyst for hydroxylation of phenol with hydrogen peroxide. Calcination was conducted at various temperatures (400, 500, 600 and 700°C)in order to observe the effect on the structure and physicochemical properties towards catalytic activity for producing hydroquinone. The structure and physicochemical properties of the TiO2/TS-1 catalyst were characterized by several techniques, such as X-ray diffraction (XRD), infrared spectroscopy, nitrogen adsorption, pyridine adsorption and hydrophilic measurement. The results show that by increasing the calcination temperature,the surface acidity of the catalyst was also increased.TheTiO2/TS-1 catalyst calcined at 500°Cproved to be optimal for hydroquinone production, in which the anatase-rutile phase may be present dispersed on the MFI framework
Kajian Peningkatan Akurasi Matriks Asal-Tujuan yang Dihasilkan dari Data Arus Lalulintas pada Kondisi Keseimbangan
Get PDFInformasi kondisi arus lalulintas sangat berguna pagi pengguna jalan karena pengguna jalan tersebut dapat memilih dan menentukan rute perjalanan terbaik yang akan dilaluinya sebelum melakukan perjalanan. Penelitian ini bertujuan akhir untuk mengembangkan sistem informasi arus lalulintas bagi pengguna jalan untuk wilayah Kota Bandung, yang dikembangkan menggunakan data arus lalulintas secara waktu nyata. Masukan utama yang diperlukan untuk mengembangkan sistem informasi tersebut adalah Matriks Asal-Tujuan (MAT) yang dikembangkan berdasarkan informasi arus lalulintas. Pada penelitian tahap ini telah ditinjau beberapa faktor yang berpengaruh terhadap peningkatan akurasi MAT yang dihasilkan dari data arus lalulintas, dimana model Gravity (GR) digunakan sebagai model sebaran pergerakan. Jenis metode estimasi yang akan ditinjau pengaruhnya adalah: Kuadrat-Terkecil (KT), Kemiripan-Maksimum (KM), Inferensi-Bayes (IB), dan Entropi-Maksimum (EM). Sedangkan model pemilihan rute yang akan ditinjau pengaruhnya adalah model all-or-nothing dan keseimbangan. Hasil penelitian menyimpulkan bahwa terdapat tingkat keakurasian yang cukup tinggi dalam proses estimasi MAT. Hal tersebut ditunjukkan berdasarkan nilai optimum dari fungsi tujuan serta hasil pengujian statistik
S-Wave Velocity Structure beneath Southwest North America from Seismogram Comparisons of the Mexico Earthquake on 22 June 1997
Get PDFThis research investigates earth structure beneath the Southwest North America landmass, especially between Mexico and California. Models based on S wave velocities for this area were obtained by carrying out seismogram fitting in time domain and three Cartesian components simultaneously. The data used is from an event, coded as C052297B that occurred in the state of Guerrero, Mexico and it was fitted to synthetic data computed with the GEMINI program at TS network stations. Earth model IASPEI91 and SPREM were used as input to create the synthetic data. Real and synthetic seismograms were subjected to a low-pass filter with a frequency corner of 20 mHz. Waveform analysis results show very unsystematic and strong deviations in the waveform, arrival times, amount of oscillation and the height of the wave amplitude. Discrepancies are met on S, Love, Rayleigh and ScS waves, where the stations epicentral distances are below 300. Deviation in analysis waveform because of the usage of model 1-D of SPREM and IASPEI91, because the 1-D was a kind of average value an elastic property at one particular depth of global earth. With the method of waveform analysis we can see how sensitive waveform is to structures within the layers of the Earth. To explain the discrepancies, a correction to the earth structure is essential. The corrections account for the thickness of the crust, speed gradient of h, the coefficient for the h and v in the upper mantle for surface wave fitting, a small variation of the S speed structure at a layer under the upper mantle above 771 km for S wave fitting, and a small variation at the base the mantle layers for ScS wave fitting. At some stations, a correction for S speed structure have yielded P wave fitting. Results of this research indicate that the 1-D earth model obtained through seismogram fitting at every hypocenter-observation station pair is unique. The Swave velocity on the upper mantle has strong negative anomalies. This paper criticized the previous earth models in the same area, which have been published by other seismologists, by analyzing the seismogram of C052297B earthquake in the TS seismological network station
The Magnetic Properties of Indonesian Lake Sediment: A Case Study of a Tectonic Lake in South Sulawesi and Maar Lakes in East Java
Get PDFMagnetic properties of sediments from two different environmental settings in Indonesia have been studied using rock magnetic methods and scanning electron microscopy (SEM). In the first setting, magnetic measurements were conducted on core sediments from two maar lakes in East Java (Lakes Lading and Bedali) that represent very confined environments where sediments are derived mainly from rocks and soils within the craters. In the second setting, similar measurements were obtained on core sediment from Lake Matano, a cryptodepression lake in tectonically active South Sulawesi where the area around the lake is dominated by highly magnetic lateritic soils. The results show that the predominant magnetic mineralogy in sediments from Lakes Lading, Bedali, as well as Matano is pseudo-single domain (PSD) magnetite (Fe3O4). Compared to that of Lake Matano, the maar lake sediments of Lakes Lading and Bedali have higher magnetic susceptibility as well as high intensity of ARM and SIRM. Variations in magnetic susceptibility in all core sediments are controlled mainly by the concentration of magnetic minerals. The homogeneity of magnetic minerals in these three lakes sediment provides an excellent setting for interpreting paleoclimatic signals as they will be recorded as anomalies of magnetic susceptibility
Existence and Uniqueness Results for Difference Φ-Laplacian Boundary Value Problems
Get PDFThis paper is devoted to study the existence and uniqueness of solutions to nonlinear difference Φ-Laplacian boundary value problems with mixed and Dirichlet boundary conditions
Five Layers Aurivillius Phases Pb2-xBi4+xTi5-xMnxO18: Synthesis, Structure, Relaxor Ferroelectric and Magnetic Properties
Get PDFSynthesis of five layers Aurivillius phases, Pb2-xBi4+xTi5-xMnxO18 (0 "žT x "žT 1) were carried out by molten salts method using eutectic mixture of Na2SO4/K2SO4 salts (1:1 molar ratio) as the flux. The samples were characterized by X-ray diffraction powder and refined by Le Bail technique. The refinement results revealed that the samples with composition x = 0, 0.2, 0.4, and 0.6 formed five layers Aurivillius with the space group B2cb; however, the samples with x = 0.4 and 0.6 contained impurity as BiMnO3 and the additional phase of four layers Aurivillius (PbBi4Ti4O15) was also observed for x = 0.6. The samples with x = 0.8 and 1 resulted in two phases: four layers Aurivillius and BiMnO3. The dielectric properties of the Pb2-xBi4+xTi5-xMnxO18 show broad peaks with the temperature of the maximum of the dielectric constant (Tm) at temperature of 295, 295, 304, and 343"žaC at a frequency of 2 MHz for x = 0, 0.2, 0.4, and 0.6, respectively. The Tm of these samples is shift to the left with decreasing frequency as indication of relaxor ferroelectric behavior. The samples with x = 0.8 and 1 show anomaly at 514"žaC and 551"žaC which correspond to the transition phase of four layers Aurivillius. Magnetic properties for all samples containing Mn are paramagnetic
A Cyclical Nurse Schedule Using Goal Programming
Get PDFScheduling is a very tedious task in organizations where duty is around the clock. Constructing timetable for nurses in hospital is one of the challenging jobs for the head nurse or nurse manager. It requires a lot of time to spend for generating a good and fair timetable. Thus, in this study, we propose a cyclical nurse scheduling model using a 0-1 goal programming that would help the head nurse or nurse manager to have less effort on building new schedules periodically. The proposed model satisfies the stated hospital's policies and the nurses' preferences. The result obtained from this model gives an optimal solution where all goals are achieved. The model also provides an unbiased way of scheduling the nurses and thus leads to an overall higher satisfaction and fairness to the nurses and the hospital management
In vitro and In Silico Studies on Curcumin and Its Analogues as Dual Inhibitors for cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2)
Get PDFCurcumin has been widely reported as an anti-inflammatory agent isolated from the plant Curcuma longa L. (turmeric). This anti-inflammatory activity was associated with the ability of this compound to inhibit the activity of both cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) in arachidonic acid metabolism. Dual COX-1 and COX-2 inhibitors are preferred to be employed in the therapy of chronic inflammatory diseases compared to selective inhibitors, since it was reported that the use of selective inhibitors led to severe adverse side effect. In the present study, in vitro and in silico assays on curcumin and its analogues as dual inhibitors for both COX-1 and COX-2 were performed. The results provide theoretical contribution in understanding the ligand-protein interactions at the molecular level to develop new curcumin analogues which possess better anti-inflammatory activity as well as to avoid unsolicited side effects
Kajian Unit Pengolahan Menggunakan Media Berbutir dengan Parameter Kekeruhan, TSS, Senyawa Organik dan pH
Get PDFA field trial of flocculation using gravel bed has been done using PDAM's Kota Bandung as the location. The reactor used a PVC pipe that consisted of an average diameter of 2,025 cm gravel. PDAM's raw water was used as throughout the experiment. As coagulant, PAC (Poly Alumunium Chloride) is used. The results show that the reactor can reduce the organic content down to 3,02 mg/L with the removal efficiency up to 73,17%. And it also can reduce the turbidity down to 0,5 NTU with removal efficiency up to 96%. The G.td value was 6946, which down below the average G.td used in hydraulic flocculation. Overall, the flocculation has a prospect to be used in operational scale
Simulasi Pemohonan Listrik (Electrical Treeing) pada Isolasi Polimer dengan Menggunakan Metode Cellular Automata
Get PDFRecently, polymeric insulating materials are widely used for high voltage cables. During operation, a field enhancement sites such as void and protrusion may exist in the polymeric insulation. Degradation of the insulation may occur and the so-called electrical treeing will grow. The electrical treeing appears in the polymeric insulation in the form of tree-like structure with very fine cylindrical channels similar to the trunks and branches in an actual tree. The appearance of an electrical treeing is a sign that a harmful degradation is developing in the insulation. In order to avoid the electrical treeing to occur in the polymeric insulation and for diagnosing of the condition, it is important to know the behavior of the electrical treeing and the correlation with the insulation materials. This paper reports a computer simulation results of the behavior of the electrical treeing using Cellular Automata. The simulation was done in polymeric materials with various critical electric fields. The simulation results showed that selection of polymeric insulating materials with high critical field is a very important step in the design of insulation