Journal of Mathematical and Fundamental Sciences
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Pemodelan TEC Regional dari Data GPS Stasiun Tetap di Indonesia dan Sekitarnya
Get PDF Ionosphere affect propagation of electromagnetic waves through it by adding a transmission delay time. In GPS positioning and navigation, ionospheric delay is largest source of error after error from Selective Availability (SA) was turned off. For GPS positioning precisely ionospheric effect must be estimated so ionospheric correction can be determinated to eliminate ionospheric effect on GPS observation. In positioning by using GPS single frequency, ionospheric correction can be obtained from GPS dual frequency receiver at reference station or model. This paper describes method of determination and modeling of regional total electron content (TEC) from continuous GPS station in Indonesia and it's around. Spatial model of TEC at certain time is estimated by using polynomial function. Diurnal variation of polynomial model coefficient at certain hour from 00.00 "“ 23.00 UT is estimated with Fourier expansion
Hawking Temperature of the Reissner-Nordstrom-Vaidya Black Hole
Get PDFWe have derived the Hawking temperature of the Reissner-Nordstrom-Vaidya black hole by the use of both the radial null geodesic and the complex path methods. We have obtained that the mass dependence of the temperature in the Reissner-Nordstrom-Vaidya black hole is not as simple as that in the Schwarzschild black hole, but still we regain the conclusion, as in the case of the Schwarzschild black hole, that a higher Hawking temperature corresponds to a lower mass of a black hole
Studi Pengembangan Model Turbulen κ-ε untuk Sirkulasi Arus II: Aliran Turbulen Dua Dimensi pada Saluran Ekspansi
Get PDFMakalah ini menyajikan hasil studi pemodelan mengenai pola aliran turbulen 2 dimensi pada sebuah saluran yang mengalami ekspansi dengan memanfaatkan model depth averaged κ-ε. Model numerik dikembangkan berdasarkan metoda beda hingga, dimana untuk pemecahan persamaan hidrodinamik digunakan kombinasi metoda ekplisit Mac Cormack dan metoda pemisahan operator splitting. Sebagai tracer untuk melakukan visualisasi struktur aliran digunakan model transport kualitas air. Suku konveksi, difusi, dan reaksi diselesaikan dengan skema QUICKEST, Central Scheme, dan Euler Scheme. Hasil yang dicapai model dalam mensimulasikan pola arus untuk kasus saluran lurus dan ekspansi menunjukan tingkat kesesuaian yang cukup baik dengan hasil pengukuran di Laboratorium. Dibandingkan dengan model non turbulen, hasil model menunjukkan peningkatan akurasi yang signifikan dalam hal besar kecepatan arus, pola arus dan sebaran konstituent kualitas air, terutama pada zona resirkulasi. Model dapat mensimulasikan pola sirkulasi arus dan terbentuknya vorteks pada zona sirkulasi. Namun demikian, untuk aliran dengan bilangan Reynold cukup rendah, osilasi dan ketidakstabilan numerik masih menjadi kendala
Diffuse Neutron Scattering of KBr at Room Temperature and Its Application as Background Function in Rietveld Analysis
Get PDFDiffuse neutron scattering from powder KBr was measured at room temperature. The oscillatory diffuse scattering is clearly observed. The diffuse scattering theory including correlation effects among thermal displacements of atoms is applied to background function in the Rietveld analysis. The observed scattering data are analyzed by including the correlation effects among thermal displacements of first, second and third nearest neighboring atoms. The inter-atomic distance and temperature dependence of the values of correlation effects is discussed
Thermal Structure of Subducting Slab along the Java Arc and Its Significance to the Volcanoes Distribution
Get PDFJava Island has a unique tectonic features and one of it is the pattern of the volcano distribution along the island. The volcano pattern occurrence might be connected to the deeper process of geodynamic. Hence, thermal structure modeling is employed to find any association between the subducting plate and the tectonic of the overriding plate. Thermal structure of a subducting plate depends on the age of the lithosphere and the dip of the subduction. With the lithospheric age increases from west to east of Java, varies from about 90 my to 120 my old, there are dissimilarities in thermal structure models. The comparison with volcanoes positions shows that differences of thermal structure might have associated to variation in the formation of volcanoes in Java Island
Locating-Chromatic Number of Amalgamation of Stars
Get PDFLet G be a connected graph and c a proper coloring of G . For i Æ’1,2,Æ’»,k define the color class i C as the set of vertices receiving color i . The color code c (v) "ž¨ of a vertex v in G is the ordered k -tuple 1 ( ( , ), , ( , )) k d v C Æ’» d v C where ( , ) i d v C is the distance of v to i C . If all distinct vertices of G have distinct color codes, then c is called a locating-coloring of G . The locating-chromatic number of graph G , denoted by ( ) L ƒÓ G is the smallest k such that G has a locating coloring with k colors. In this paper we discuss the locating-chromatic number of amalgamation of stars k ,m S . k ,m S is obtained from k copies of star 1,m K by identifying a leaf from each star. We also determine a sufficient condition for a connected subgraph k ,m H "ž~ S satisfying , ( ) ( ) L L k m ƒÓ H "žT ƒÓ
Synthesis and Biological Activity of Novel Platencin Derivatives
Get PDFThe biological mode of action of platencin, a potential lead molecule for a new class of antibiotics, is detailed. Furthermore, enantiopure syntheses of several platencin derivatives are described, of which the core structure can be accessed in two exceedingly simple steps from commercially available starting materials. Furthermore, the antibiotic properties of the derivatives was evaluated
Land Degradation Model Based on Vegetation and Erosion Aspects Using Remote Sensing Data
Get PDFThe study of land degradation in various geographic conditions in the world using remote sensing is still become a concern amongst researchers because it has been proven as one of the most effective ways. In Indonesia, East Kalimantan province is one of the experiencing land area degradation due to intensive exploitation of natural resouces since 1970. The degradation model proposed in this study is modeled using a combination of ASTER and Landsat ETM+ imagery, both taken on February 27, 2001. The model composed of both two aspects: erosion aspect and vegetation aspect. Vegetation aspect is a function of suppression of vegetation from Crippen and Blom method and spectral angle a of Spectral Angle Mapper (SAM) algorithm. The erosion aspect is calculated from erosion prediction and depends on the constant factors of b as well, and the latter is said as a function of Normalized Difference Vegetation Index (NDVI) value. Based on the validation using spectral based degradation map and Land Degradation Index of Chikhaoui et al, our model proves the ability to map land degradation, especially to better distinguish the classification of land degradation at very-slightly to very-severe intensity and the ability to differentiate water body, swamp or river
An Asymptotic Study of the Steady State Model of Oxygen Diffusion in Tissue Regions
Get PDFOxygen plays an important role in the metabolism of cells inside the human body. The transfer of oxygen from blood to tissue takes place in capillaries through a diffusion process. The capillary-tissue region is usually represented by the so-called Krogh cylinder model, in which the distribution of the oxygen concentration in a tissue region leads to a diffusion equation with oxygen consumption rates following the Michaelis-Menten kinetics. In this paper, we restrict ourselves to the steady state case and solve the equation analytically by means of asymptotic expansion for a particular limit of the oxygen consumption rate. Results show that there exists a critical ratio between supply and consumption of oxygen in the tissue region in order to fulfill the cell's oxygen requirements. Above from this critical ratio, we also found a critical distance in the tissue region above which the oxygen concentration vanishes. We compared our asymptotic results with numerical simulations, which turned out to be quite in agreement
Tinggi Maksimum Selubung Paket Gelombang Bikromatik
Get PDFPrevious numerical and experimental investigations found that some envelopes of bichromatics surface water waves show deformation during their propagation along the wave tank in Hydrodinamic Laboratory. In this paper we present investigation on the maximum amplitudes of bichromatics envelopes at every position along the tank, to observe the amplification factor of a signal deformation . As we consider a signaling problem, a spatial Nonlinear Schrodinger (sp-NLS) model is used here. The profiles of waves envelope as a function of time and space are computed numerically from this model. Investigations are done for some different amplitudes and frequencies of bichromatics envelopes at wave generator to show that these two parameters affect the amplification factor and the periode of maximum amplitudes of envelopes