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Jurnal Matematika & Sains
Published by Institut Teknologi Bandung
ISSN : -     EISSN : -     DOI : -
Core Subject : Education,
Mathematics
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Articles 339 Documents
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The Exact Eigenvalues of the Neutrino Mass Matrix in Global Lepton and   Interchange Symmetry Agus Purwanto; Herlik Wibowo
Jurnal Matematika & Sains Vol 16, No 1 (2011)
Publisher : Institut Teknologi Bandung

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The 3x3 Majorana neutrino mass matrix is evaluated. The mass eigenvalues depend on the diagonal entries and three mixing angles. Two spesific cases such as conserving the global lepton number and mu-tau interchange symmetry are considered. In the case of conserving global lepton number, inverted mass hierarchy for bimaximal mixing is obtained. The mixing matrix, namely PMNS matrix, doesnt valid for all cases. The shape of mass matrix satisfying mu-tau interchange symmetry is proposed and the eigenvalues that lead to neutrino mass hierarcy are also obtained after applying a new PMNS matrix.
Early Warning System for Dengue Hemorrhagic Fever (DHF) Epidemics in Makassar Halmar Halide; Rais Rais; Peter Ridd
Jurnal Matematika & Sains Vol 16, No 1 (2011)
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A three-month in advance warning system for upcoming DHF epidemics is developed. The system uses a simple predictive regression model based on past and present DHF cases, climate and meteorological observations as inputs to predict future DHF cases. Using Peirce score as a measure of prediction skill, the model only successfully predicts a moderately-severe epidemic at lead times of up to 6 months. Another model uses a discriminant method is also developed. This model gives much higher skill score and longer lead times than that of the regression model. The economic benefit of using the discriminant models forecast to protect a family from an epidemic is also demonstrated. It is shown that families who are implementing such a prediction into their decision making process gain more benefit than those with un-informed decisions. 
Forecasting Tourism Data Using Neural Networks - Multiscale Autoregressive Model Brodjol Sutijo; Suhartono Suhartono; Alfonsus J. Endharta
Jurnal Matematika & Sains Vol 16, No 1 (2011)
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Neural Networks - Multiscale Autoregressive (NN-MAR) model is a development of neural network. The network is built by using wavelet theories for time series forecasting. There are few research explaining how NN-MAR model can be used for forecasting seasonal time series data. The main aspect for forecasting seasonal time series data is the lag inputs, which should include seasonal lags. The procedure starts from Maximal Overlap Discrete Wavelet Transform (MODWT) decomposition. For non-stationary data, the differencing process is used to get a stationary data. From the decomposition process we get the scale and wavelet coefficients. The lags of these coefficients are used as the inputs in the network. In the hidden layer, the number of hidden neurons is chosen by using the criterion of R2incremental and F-test, so that we get the best NN-MAR model. The aim of this research is to build NN-MAR model for seasonal time series data, such as tourism data. The number of international tourist coming to Soekarno-Hatta airport in Jakarta and to Ngurah Rai airport in Bali are used as the case study.
Osmotic Adjustment and Solutes Accumulation in Leaves of Wheat (Triticum aestivum L.) during Water Deficit Song Ai Nio; Timothy D. Colmer; Len J. Wade; Gregory Cawthray
Jurnal Matematika & Sains Vol 16, No 1 (2011)
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This study examined osmotic adjustment (OA) expression and solutes accumulated in leaf segments of wheat cultivar Hartog (with high OA capacity) exposed to polyethylene glycol (PEG). Osmotic adjustment (OA) is one of the traits that contribute to plant tolerance of water deficits. The objectives were to evaluate OA expression as response to increasing PEG concentration and treatment periods, and to examine the concentrations of inorganic and organic solutes in the tissues, as related to OA development at different duration of PEG treatments. The experiment consisted of 4 PEG treatments (0, -0.5, -1.0 and -1.5 MPa), 5 sampling times (0, 12, 24, 48 and 72 h) and 3 replicates. PEG treatments were imposed as -0.5 MPa steps, every 12 h. The leaf segments were sampled for leaf water content, osmotic potential, OA, inorganic solutes (K+, Na+ and Cl-), and organic solutes (glycinebetaine, proline and total soluble sugars). OA was expressed in leaf segments exposed to water deficit under PEG -0.5 MPa, but not at -1.0 MPa or higher. The differences of measurements in PEG -0.5 MPa compared to PEG -1.0 and -1.5 MPa, were clearly observed at 48 h. Amongst the solutes, Na+ and proline contributed to leaf OA.
A Qualitative and Quantitative Evaluation of Terpenoid and Alkaloid in Root and Stem of Pasak Bumi (Eurycoma longifolia Jack) Anisa Rahmalia; Rizkita R. Esyanti; Iriawati Iriawati
Jurnal Matematika & Sains Vol 16, No 1 (2011)
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Herbal, as health solution, regained its popularity because many studies showed advantages of using it. One of the most industrially needed herbal materials is the extract of pasak bumi (Eurycoma longifolia Jack), which is popular for its alleged sexual-enhancing properties. E. longifolia was known to produce secondary metabolites, especially terpenoid and alkaloid. The presence of major alkaloids and terpenoids in root and stem of E. longifolia was evaluated quantitatively by analyzing the ethanol extract of root and stem of E. longifolia using GC-MS. Qualitative analysis was conducted through colorimetric test on both extracts by using Dragendorff and Lieberman-Burchad reagents. Colorimetric test showed that there was a difference in both terpenoid and alkaloid amounts on ethanol extract of both root and stem. GC-MS analysis showed that the ethanol extract of E. longifolia from the root contained 14.631% terpenoid and that from the stem was only 7.781%. The ethanol extract of E. longifolia from the stem contained 1.785 % of alkaloid, while that from the root was 5.117 % from total compounds. Major alkaloids found on both organs were 3-Methyl-1-oxo-2,3-dihydro-1H-pyrazolo[4,3-c][1,10] phenanthroline, which showed higher concentration in root. Major terpenoid in root included 2H-1-Benzopyran-2-one, 3-phenyl- (coumarin derivate), whilst that in stem was Stigmasterol. These substances have different activities in target cells. Therefore, the knowledge of active compounds in organ parts of pasak bumi will lead to a more efficient production process.
Calcium Release from Cell Walls of Pea Epicotyls Caused by Proton Extrusion during Fusicoccin Action Idam Arif
Jurnal Matematika & Sains Vol 16, No 2 (2011)
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Proton and calcium net fluxes were measured simultaneously during fusicoccin action on peeled Pisum sativum L. epicotyl segments. The measurement employs ion selective microelectrodes to determine the fluxes. The membrane potential of parenchymal cells during the action was also measured. Fusicoccin at 10-3 mol m-3 causes immediate proton and calcium effluxes reaching about 60 and 80 nmol m-2 s-1 respectively within 40 minutes. It also causes membrane hyperpolarization of about -22 mV. The responses to 10-2 mol m-3 fusicoccin are larger. The data fit the Weak-Acid Donnan Manning model for exchange between wall calcium and extruded protons during fusicoccin action on peas. Keywords: Wall calcium, Ion exchange, Proton extrusion, Fusicoccin. Pelepasan Kalsium dari Dinding Sel Epikotil Kacang Polong yang Disebabkan oleh Ekstrusi Proton Selama Aksi Fusicoccin Abstrak Flux netto ion proton dan kalsium diukur secara bersamaan selama aksi fusicoccin pada segmen epikotil Pisum sativum L. yang dikupas epidermisnya.  Pengukuran tersebut memakai mikroelektroda yang selektif hanya pada suatu ion untuk menentukan besarnya flux ion tersebut. Potensial membran sel parenkim selama aksi fusicocin tersebut juga diukur. Fusicoccin dengan konsentrasi 10-3 mol m-3 langsung menyebabkan efflux ion proton dan kalsium yang masing masing mencapai sekitar 60 dan 80 nmol m-2 s-1 dalam waktu 40 menit. Fusicoccin dengan konsentrasi yang sama  juga menyebabkan hiperpolarisasi membran sel sekitar -22 mV. Fusicoccin dengan konsentrasi yang lebih tinggi, yaitu10-2 mol m-3, menyebabkan respon yang  lebih besar. Data tersebut bersesuaian dengan model Weak-Acid Donnan Manning yang menjelaskan pertukaran antara kalsium yang terkondensasi dalam dinding sel dengan proton yang keluar dari dalam sel selama aksi fusicoccin pada kacang polong. Kata kunci: Kalsium dinding sel, Pertukaran ion, Ekstrusi proton, Fusicoccin.
Investigation of Ground State Properties of Neutron-Rich Titanium Isotopes by the Use of SHF+BCS Method Muhammad Zamrun; Ida Usman; La Aba
Jurnal Matematika & Sains Vol 16, No 2 (2011)
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The ground state properties of Ti-isotopes (44,46,48,50,52,56,58Ti) such as binding energy, density distribution, kinetic energy density distribution and local potential for proton and neutron are investigated using the Skyrme-Hartree-Fock (SHF)+Bardeen-Cooper-Schrieffer (BCS) method. In performing the SHF+BCS calculations, we use three most successfully Skyrme force parameters that are SIII, SkM*, and Sly4. It is found that the binding energy obtained with these three parameters is in well agreement with the experimental data. The calculated density distributions, kinetic energy densities and local potentials for proton and neutron using the three parameters for each titanium isotope are similar to each other, especially the slope and in the surface region. Our study indicates that SHF method is adequate to describe the ground state properties of the nucleus. Keywords: Skyrme-Hartree-Fock, Binding energy, Density distribution, Local potential. Investigasi Sifat-sifat Keadaan Dasar dari Isotop Titanium yang Berlebih Neutron dengan Metode SHF+BCS Abstrak Sifat-sifat keadaan dasar dari isotop-isotop Titanium (44,46,48,50,52,54,56,58Ti) berupa energi ikat, distribusi densitas, distribusi densitas energi kinetik serta potensial lokal untuk proton dan netron ditelaah dengan menggunakan metode Skyrme-Hartree-Fock (SHF)+Bardeen-Cooper-Schrieffer (BCS). Dalam melakukan perhitungan dengan metode SHF+BCS ini digunakan tiga set paramater untuk gaya-gaya Skyrme yaitu parameter SIII, SkM* dan Sly4. Energi ikat yang diperoleh dengan tiga set parameter ini sesuai dengan hasil eksperimen untuk semua isotop Titanium. Distribusi densitas, densitas energi kinetik dan potensial lokal yang diperoleh dengan tiga parameter tersebut untuk setiap isotop titanium  mirip satu sama lain terutama untuk kemiringan dan daerah permukaan. Telaah ini menunjukkan bahwa metode SHF dapat digunakan untuk menentukan sifat-sifat keadaan dasar inti atom. Kata kunci: Skyrme-Hartree-Fock, Energi ikat, Distribusi densitas, Potensial lokal.
Isolation of chlorophyll a from spinach leaves and modification of center ion with Zn2+: Study on its optical stability Nurhayati Nurhayati; Veinardi Suendo
Jurnal Matematika & Sains Vol 16, No 2 (2011)
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It is well-known that the pure chlorophyll a, which has a magnesium central ion, is not stable against high intensity light exposure. It was observed that it degrades with a lifetime of 12.8 seconds based on the evolution of fluorescence signal intensity under the irradiation of 60 mW diode laser at 405 nm that resonates with its Soret band. In order to be applied as an optical material, the stability of chlorophyll a needs to be improved. One way to enhance the photostability of chlorophyll a is by changing the center ion, where in this study Mg2+ in chlorophyll a is replaced by Zn2+ to form Zn-pheophytin a. The results show a significant increase in the decay lifetime from 12.8 to 49.5 seconds by introducing the Zn2+ ion into porphyrin ring. It was observed that the absorption maximum of Soret band is red shifted from 413 nm to 424 nm after the introduction of Zn2+ into porphyrin ring, while the Q band maximum is blue shifted from 667 nm to 658 nm. The mass spectroscopy result confirmed that Mg2+ ions have been replaced by Zn2+. The results show the presence of m/z 933.5 and m/z 971.5 species, which are typical for Zn-pheophytin a and Zn-pheophytin a dihydrate, respectively. Keywords: Chlorophyll a, Photodegradation, Optical materials, Optical stability, Porphyrin, Zn-pheophytin a.   Isolasi Klorofil a dari Daun Bayam dan dan Modifikasi Pusat Ion dengan Zn2+: Studi Stabilitas Optik Abstrak Telah diketahui secara umum bahwa klorofil a murni, dengan ion pusat magnesium, bersifat tidak stabil terhadap penyinaran berintensitas tinggi. Telah diamati pada penelitian ini bahwa klorofil a mengalami degradasi dengan waktu hidup 12,8 detik yang diperoleh dari evolusi intensitas sinyal fluoresensi pada penyinaran dengan laser dioda berdaya 60 mW pada 405 nm yang beresonansi dengan pita Soret. Agar dapat diaplikasikan sebagai material optik, kestabilan klorofil a perlu ditingkatkan. Salah satu cara untuk meningkatkan kestabilan klorofil a adalah mengganti ion pusatnya. Dalam penelitian ini kation yang digunakan adalah Zn2+ yang akan membentuk Zn-pheophytin a. Hasil penelitian menunjukkan peningkatan nilai waktu hidup yang signifikan dari 12,8 detik menjadi 49,5 detik dengan masuknya ion Zn2+ ke dalam cincin porfirin pada klorofil a. Diamati bahwa penyerapan maksimum pita Soret mengalami pergeseran merah dari 413 nm ke 424 nm setelah pergantian ion pusat dengan Zn2+, sedangkan pita Q maksimum mengalami pergeseran  biru dari 667 nm menjadi 658 nm. Hasil spektroskopi massa memastikan bahwa ion Mg2+ telah tergantikan oleh ion Zn2+. Ditemukan keberadaan spesi dengan m/z 933,5 dan m/z 971,5 yang merupakan m/z spesifik untuk Zn-pheophytin a dan Zn-pheophytin a dihidrat. Kata kunci: Kestabilan optik, Klorofil a, Fotodegradasi, Material optik, Porfirin, Zn-pheophytin a.
Synthesis of Isothiazolone and 5-Chloroisothiazolone Derivatives Through Simple Amidation and Cyclization Processes Rosalina Wisastra; Frank J. Dekker; Megawati Santoso
Jurnal Matematika & Sains Vol 16, No 2 (2011)
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Several methyl alkanoate substituted isothiazolones and 5-chloroisothiazolones were synthesized using a simple amidation process of 3,3’-dipropionic acid and chlorination during 3,3’-dithiobispropanamide cyclization process, respectively. The results showed that 5-chloroisothiazolones were produced in a good yield (40-70%), whereas the isothiazolones are produced in moderate yield (±20%). Keywords: Isothiazolone, 5-chloroisothiazolone, Organic synthesis, 3,3’-dithiopropionic acid. Sintesa Derivatif Isothiazolon dan 5-Kloroisothiazolon melalui Proses Amidasi dan Siklisasi Sederhana Abstrak Berbagai senyawa turunan dari isothiazolon tersubsitusi oleh metil alkanoat dan 5-kloroisothiazolon disintesis masing-masing melalui proses amidasi sederhana pada senyawa 3,3’-asam dipropionat dan klorinasi saat terjadinya siklisasi 3,3’-dithiobispropanamida. Dalam penelitian ini, 5-kloroisothiazolon tersubsitusi oleh metil alkanoat dapat dihasilkan dengan yield yang memadai (40-70%), sedangkan isothiazolon dapat dihasilkan dengan yield 20%. Kata kunci: Isothiazolon, 5-kloroisothiazolon, Sintesis organik, Asam 3,3’-dithiopropionat
Solutions of Natural Convection of Nanofluids in a Parallelogrammic Enclosure by Finite Difference Method Habibis Saleh; Sri Basriati; Ishak Hashim
Jurnal Matematika & Sains Vol 16, No 2 (2011)
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Detailed numerical calculations for heat transfer enhancement utilizing nanofluids in a parallelogrammic enclosure are presented in this paper. The sloping walls are maintained isothermally at different temperatures. The top and bottom horizontal straight walls are kept adiabatic. To simplify the effort in matching the grid mesh with the sloping walls of the parallelogram, the computational domain is mapped onto a rectangular shape using a non-linear axis transformation. Transport equations are modeled by a stream-vorticity formulation and are solved numerically by finite difference method. Based upon the numerical predictions, the effect of the base angle of the parallelogrammic enclosure on flow and temperature pattern and the heat transfer rate within the enclosure are presented. Increasing the base angle was found to decrease the heat transfer rate. Keywords: Numerical method, Natural convection, Nanofluids.   Solusi Konveksi Alami Fluida Nano dalam Bangun Jajaran Genjang Tertutup Menggunakan Metode Elemen Hingga Abstrak Dalam makalah ini disajikan perhitungan numerik secara rinci untuk permasalahan peningkatan perpindahan kalor memanfaatkan fluida nano dalam bangun jajarangenjang tertutup. Kedua sisi miring jajarangenjang tersebut dipertahankan  isotermal pada suhu yang berbeda. Sisi atas dan bawahnya dipertahankan dalam keadaan adiabatik. Untuk menyederhanakan usaha dalam menyesuaikan jaring-grid dengan sisi-sisi miring jajarangenjang, domain komputasi dipetakan ke bentuk persegi panjang menggunakan transformasi sumbu tidak linear. Persamaan-persamaan transport dimodelkan dengan rumus aliran-pusaran dan diselesaikan menggunakan metode beda hingga. Berdasarkan prediksi numerik, pengaruh dari sudut dasar jajarangenjang  pada pola aliran dan suhu dan juga tingkat perpindahan kalor dalam jajarangenjang disajikan. Disimpulkan bahwa pembesaran sudut dasar jajarangenjang didapati menurunkan tingkat perpindahan kalor. Kata kunci: Metode numerik, Konveksi alami, Fluida nano.

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