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INDONESIA
Jurnal Matematika & Sains
Published by Institut Teknologi Bandung
ISSN : -     EISSN : -     DOI : -
Core Subject : Education,
Mathematics
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Articles 8 Documents
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Search results for , issue " Vol 16, No 1 (2011)" : 8 Documents clear
Isomerisasi Linoleat dalam Minyak Jarak Hasil Dehidrasi Menjadi Linoleat Terkonjugasi dan Pemisahannya dengan Kromatografi Kolom Fasa Diam Silika Gel yang Diimpregnasi Perak Nitrat Marham Sitorus; Sanusi Ibrahim; Hazli Nurdin; Djaswir Darwis
Jurnal Matematika & Sains Vol 16, No 1 (2011)
Publisher : Institut Teknologi Bandung

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Abstract

The main component of dehydrated castor oil (DCO) is linoleic and conjugated linoleic acid (CLA) as triglyseride forms.  This research aim is to find out suitable method for linoleic isomerization of DCO into CLA. Isomerization method must be made chemoselective in order to prevent safonification and transesterification. Isomerization method with 2M NaOH in n-butanol, 1% KOH (w/v) without solvent and irradiated by microwave with iodine as an initiator were tested respectively. CLA was seperated by using column chromatography that AgNO3 impregnated silica gel as a stationary phase. Seperation was based on the differences of coordination bond strenght between the double bond and silver ion. Its  the more unsaturation and trans isomer the more srongly the molecule is retained. Gradient elution was carried out by various ratio of hexane and acetone (v/v) e. g : 97.5 : 2.5, 95 : 5, 90 : 10, 80 : 20, 70 : 30 and  60: 40 with  8 x 5 mL. Each of fraction was analyzed by using TLC and the spot detection was made by UV lamp. The results was  analyzed by using GC, FTIR, UV and GC - MS and Its compared with the standard data. The best isomerization  was  conducted  by microwave irradiated using iodine as an initiator with a conversion factor of 1.97 %.  Seperation of CLA could be made by column chromatography that AgNO3 impregnated silica gel as a stationary phase. The best result  was conducted by eluting with 95: 5 (v/v) of hexane-acetone. The compositions of seperated  were:  0,91% (9c-2c) linoleic, 43.59% (9c/t-12t/c) linoleic, 18.58% (9c/t-1t/c)CLA, 3.46% (9t-11t) linoleic, 19.19%(9t- 1t) CLA and 0.86% ricinoleic.  The ratio of CLA : linoleic prepared was  0.77 : 1 or 70, 32 % compared to the standar with the proportions of 1.45:1.
Sintesis dan Penentuan Sifat Feroelektrik Senyawa Oksida Logam Berstruktur Aurivillius Pb2Bi3Ti3,5W0,5O15 Edi Mikrianto; Dwi Rasy Mujiyanti; Taufiqurohman Taufiqurohman
Jurnal Matematika & Sains Vol 16, No 1 (2011)
Publisher : Institut Teknologi Bandung

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Abstract

Senyawa oksida logam berstruktur Aurivillius Pb2Bi3Ti3,5W0,5O15 (PBTW) telah disintesis pada kisaran suhu 900 - 950 oC dengan metode reaksi fasa padat. Difraktogram hasil analisis XRD dibandingkan dengan database PDF (Powder Diffraction File) menggunakan Program Phasanx dan penelusuran difraksi menggunakan program Rietica dengan metode Rietveld. Hasil penelitian menunjukkan bahwa parameter sel oksida Aurivillius PBTW yaitu a = 5,2453 Å; b = 5,5363 Å; c = 41,6342 Å dengan grup ruang A21am dan sistem kristal ortorombik. Berdasarkan hasil pengukuran sifat feroelektrik didapatkan bahwa senyawa hasil sintesis dari oksida logam berstruktur Aurivillius tipe PBTW menunjukkan adanya pola histerisis. Nilai polarisasi remanen Pr(+) oksida Aurivillius tipe PBTW sebesar 12,4 C/cm2, dengan nilai Kef dan kapansitansinya 423.132 dan 489,788 nF.
30–75-day Sea Level Variations in The Equatorial Indian Ocean as Observed by Satellite Altimeter Iskhaq Iskandar
Jurnal Matematika & Sains Vol 16, No 1 (2011)
Publisher : Institut Teknologi Bandung

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Basin-wide structure of intraseasonal sea level variations in the equatorial Indian Ocean is investigated using satellite altimeter data. The spectral analysis reveals that the intraseasonal sea level variations are dominated by the 30-75-day oscillations. The spatial amplitude structures of the intraseasonal sea level inferred from the complex empirical orthogonal function (CEOF) analysis show a typical structure of equatorial Kelvin and off-equatorial Rossby waves. Moreover, the spatial phase structures of the CEOF mode reveal eastward propagating signal. The estimated phase speed does not correspond exactly to that of one particular baroclinic modes though it falls within the range expected for the first three baroclinic modes in the Indian Ocean. This may suggest that the propagating signals do not involve a single baroclinic mode, but instead the first, second and possibly higher baroclinic modes.
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)
Publisher : Institut Teknologi Bandung

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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)
Publisher : Institut Teknologi Bandung

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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)
Publisher : Institut Teknologi Bandung

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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)
Publisher : Institut Teknologi Bandung

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Abstract

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.

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