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Jurnal Matematika & Sains
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Articles 339 Documents
Studi Aplikasi Metode Potensiometri Pada Penentuan Kandungan Karbon Organik Total Tanah Abdul Haris Watoni; Buchari Buchari
Jurnal Matematika & Sains Vol 5, No 1 (2000)
Publisher : Institut Teknologi Bandung

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STUDI APLIKASI METODE POTENSIOMETRI PADA PENENTUAN KANDUNGAN KARBON ORGANIK TOTAL TANAH In recent years, ion selective electrodes have become more useful for the determination of certain ion in solutions rather than in soil system. The applications of potentiometric for the determination of the total soil organic carbon has been investigated with CO2 selective electrode as indicator electrode. The principle of the determination is base on the conversion of total soil organic carbon in the sample to CO2 and than the CO2 produced was measured potentiometrically by CO2 selective electrode. The concentration of CO2 was proportional with the total soil organic carbon in the samples. Before application for the measurement, the CO2 selective electrode must be characterized. The investigation showed that the respon time of the electrode was 2,5 minutes and it was stable for 40 seconds because the lost of CO2 to the air. The range of concentration for the measurement was between 9.09 x 10-4 M to 3.83 x 10 -1M of CO2 with the Nernst factor was 53 mV per decade and the limit of detection was 4.5 x 10-4 M of CO2 and the optimum pH of the solution was 4.8. The present of CH3COO- and H2PO4- over 10-2 M in concentrations interfered the measurement of CO2 with their potentiometric coefficient of selectivity was 0.36 and 0.133 respectively. The validity of potentiometric method for the determination of the total soil organic carbon was compared with the titrimetric method for the same samples. This investigation showed that the potentiometric method was applicable to the determination of the total soil organic carbon and it was more accurate than the titrimetric method.
Uji Selektivitas dan Penentuan Rekoveri Akhir pada Pemisahan Logam Emas dengan Metode Agregasi Hidrofobik Suharta Suharta; N. M. Surdia; Buchari Buchari; Djulia Onggo
Jurnal Matematika & Sains Vol 5, No 1 (2000)
Publisher : Institut Teknologi Bandung

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STUDI APLIKASI METODE POTENSIOMETRI PADA PENENTUAN KANDUNGAN KARBON ORGANIK TOTAL TANAH The separation of substance by hydrophobic aggregation method is always started from colloidal particles. The flaws of this technique are especially in the selectivity and recovery. This research was developing of gold separation by hydrophobic aggregation method where it was started from solution system. Complex of [AuCl4]- was chosen in this solution system. The gold selectivity from cations {Ag(I), Cu (II), Fe (III), Zn (II), Pb(II)}, and anions {SO4 2-, NO3-, Br-, I-} was studied. As a result, this method can be separated of gold with height selectivity. The selectivity is restrained by pH, and the optimum pH is 2,0. The recovery of gold with DTMAB, TTMAB, and HTMAB surfactant is 92,60 ± 0,89 %; 90,30 ± 1,32 %; and 89,40 ± 1,51 % respectively.
Patrol Observation of the Southern Dwarf Novae at The Bosscha Observatory Chatief Kunjaya
Jurnal Matematika & Sains Vol 5, No 2 (2000)
Publisher : Institut Teknologi Bandung

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STUDI APLIKASI METODE POTENSIOMETRI PADA PENENTUAN KANDUNGAN KARBON ORGANIK TOTAL TANAH  The result of patrol observation of dwarf novae at the Bosscha Observatory are presented. The images of the region of four dwarf novae, MM Scorpii, V2051 Ophiuci, V391 Scuti and V3462 Sagitarii could be taken. MM Scorpii and V391 Scuti were not detectable implying quiescence state. The eclipsing SU UMa type dwarf nova, V2051 Ophiuci was observed during its outburst. Brightness measurement using aperture photometry method yields (15.2 ± 0.3) mag. V3462 Sagitarii were also detectable and the brightness (15.3 ± 0.6) mag were derived. Therefore this star is suspected in its outburst state during the observation.
Solar Cycle Variations and its Effects on El Niño/La Niña Behaviour Iratius Radiman; Dhani Herdiwidjaja; Zadrach L. Dupe; Chatief Kunjaya; Muhammad Irfan Hakim
Jurnal Matematika & Sains Vol 8, No 2 (2003)
Publisher : Institut Teknologi Bandung

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Variations in the Solar Cycle has been known for a long time. The Solar Cycle is observed to vary from 14 to 8 years in length. The reconstructions of the annual solar total irradiance since the beginning of Maunder Minimum (from year 1600) to year 2000 show that there are envelopes of groups sunspot numbers. The intensities delineated by the envelopes are consistent with the range of CaII brightness. The timelength of the envelopes corresponds to long term variabilities such as the Gleissberg Cycle of 88 and 124 years period. A close correlation between total irradiance and sunspot number from 1610 to 2000 is found to be 0.88. Although the work of Labitzke and van Loon has clearly shown the existence of an oscillation in many atmospheric parameters with a period in the vicinity of 11 years and a phase that is related to that of solar activity, there is reluctance to accept a relationship to the 11-year solar cycle. Therefore this study aimed to pursue the investigations further by determining the correlation coefficients to lower trophospheric layers. Our studies reveal to results, which we summarized as follows: A weak correlation at 27 month delay is found between solar activities and the El Niño/La Niña phenomena. The next El Niño/La Niña event is expected to occur from year 2002 until mid 2003. A major change in the pattern of the solar cycle since 1700 appears. The sun is seen to be more frequent in its active states over the last 100 years. The length of the cycle is becoming shorter. The solar cycles modulate from 5, 8, 12 and 25-year period obtained from its total irradiance plot. The 5-year period coincides very well within the El Niño/La Niña period of 2 to 7-year. The El Niño/La Niña phenomenon has a 10-12 month duration. Every El Niño/La Niña event is separated from 24 to 84 months duration in an irregular pattern. Every El Niño/La Niña event is unique. These conclusions are drawn after decomposing the SST Anomaly Index through applied Fourier Transform. The effect of the solar cycle variations is to generate long period harmonics in the coming El Niño/La Niña events. We expect that more variability in climate will occur in the coming decade.
Crystal Structure, Magnetic Susceptibility, and ESR Measurement of BaCu2(PO4)2 Aripin Aripin; S. Mitsudo; T. Idehara; M. Mekata
Jurnal Matematika & Sains Vol 8, No 1 (2003)
Publisher : Institut Teknologi Bandung

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The crystal structure of BaCu2(PO4)2 has been refined from X-ray powder data. BaCu2(PO4)2 crystallizes into a triclinic structure which belongs to the space group P-1, which unit cell constant a = (9.226±0.023)(1) Å, b = (9.271±0,018)(1) Å, c = (10.516±0,09)(1) Å, α = (106.76±0.12)(5)o, β = (101.65±0.16)(5)o, γ = (115.70±0.3)(5)o, V = (717.96±0.05) Å3, Z = 4, and dcal = 4.20 g.cm-3. The copper atoms constitute isolated magnetic chains parallel to the [001] direction. The magnetic susceptibility measurement was preformed at temperatures ranging from 4.2 K to 300 K. The magnetic susceptibility shows a broad maximum at around 60 K. The magnetic susceptibility has been interpreted in terms of one-dimensional magnetic system. The temperature dependence of the magnetic susceptibility indicated a good agreement with ladder configuration model. In the ESR measurements, clear electron spin resonance (ESR) was observed. The integrated intensity has a broad maximum at around 60 K, which is consistent with the susceptibility result. A quantitative description gives resonance is the first triplet state of the excitation spectrum of ladder configuration.
Pengaruh Prostaglandin F2α Terhadap Fertilitas Tikus (Rattus norvegicus) Wistar Jantan Suripto Suripto; Lien A. Sutasurya; Hasanuddin Hasanuddin; Dwi Arinto Adi
Jurnal Matematika & Sains Vol 5, No 2 (2000)
Publisher : Institut Teknologi Bandung

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The effect of PGF2α on the fertility of male Wistar rat (Rattus norvegicus) has been investigated . Sexually mature male rats with a body weight of 200 to 300 g were used . Sperm numbers and quality, and mating ability, were observed after rats were subcutaneously injected with 1.5 ; 2.0 and 3.0 mg/kg body weight of PGF2α dissolved in 0.4 ml saline solution daily for 11 consecutive days for the treatment groups , respectively. Contraction of caudal epididymis and vas defferens were recorded using myograph and physiograph, whereas the concentration of PGF2α was 0.4 and 0.6 mg/ml dissolved in Tyrode. The result showed that motility and number of normal as well as abnormal sperm decreased in conjuction with the increasing dosage of PGF2α. The contraction of organs which occurred when solution was added, showed that PGF2α increased the tonus tensions of caudal epididymis as well as vas deferens. There were no differences in mating ability of the treated rats compared to the control rats, while the fertility index of treated rats was significantly (p
Reactions of Simple Indoles with o-Phthaldialdehyde: Part I Synthesis of New 11-(3-Indolyl)benzo[b]carbazoles Mardi Santoso
Jurnal Matematika & Sains Vol 5, No 2 (2000)
Publisher : Institut Teknologi Bandung

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New 11-(3-indolyl)benzo[b]carbazoles (11 and 13) can be synthesised readily in good yields from the reaction of simple indoles (8, 12) and o-phthaldialdehid (7) in the presence of phosphoryl chloride.
Synthesis of New Indolo-cyclotriveratrylene: 1,4,7-Trihydrocyclononano[2,3-b: 5,6-b: 8,9-b:]tri-1-benzylindole Mardi Santoso
Jurnal Matematika & Sains Vol 5, No 2 (2000)
Publisher : Institut Teknologi Bandung

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STUDI APLIKASI METODE POTENSIOMETRI PADA PENENTUAN KANDUNGAN KARBON ORGANIK TOTAL TANAH  A new indolo-cyclotriveratrylene: 1,4,7-trihydrocyclononano[2,3-b: 5,6-b: 8,9-b:]tri-1-benzylindole (21) was synthesized in good yield from the acid catalysed dehydration of 1-benzyl-3-hydroxymethylindole (20). The structure of the new indole cyclic trimer (21) was established by spectroscopy and microanalysis. The synthesis of the alcohol (20) was performed in two steps by alkylation of indole-3-carbaldehyde (18) followed by reduction with sodium borohydride.
Nanocomposite of Zinc Oxide and Silica With Stable Luminescence Mikrajuddin Mikrajuddin
Jurnal Matematika & Sains Vol 8, No 1 (2003)
Publisher : Institut Teknologi Bandung

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Nanocompsite of zinc oxide (ZnO) and silica (SiO2) has been produced by spray drying the mixture of ZnO and SiO2 colloids. Initially, ZnO colloid was produced by hydrolizing zinc acetate in ethanol solution and then reacted with lithium hydroxide solution. Colloid of ZnO containing nanometer-scaled particles was mixed with SiO2 colloid at definite fractions, atomized using an ultrasonic nebulizer and dried in a vertical reactor using nitrogen carrier gas. The produced powder showed a time independent luminescence spectra that is important for industrial applications.
Dampak Enso pada Faktor Hujan di Indonesia Bayong Tjasyono HK; Bannu Bannu
Jurnal Matematika & Sains Vol 8, No 1 (2003)
Publisher : Institut Teknologi Bandung

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The Indonesian region is characterized by the activity of tropospheric convection. In the ENSO (El Niño –Southern Oscillation) event, the convective clouds displace to the eastern Pacific ocean due to the weakened trade winds. The ENSO phenomenon is the biggest player in the game of annual climate variation, while monsoon plays a role in the seasonal variations. The ENSO also brings about serious climate disaster in global area, for instance in the drought Indonesia, in the food Ecuador and so on. The influence of ENSO events is profoundley felt in some parts of the Indonesian region, i.e., the number of rainfall less than that in the pre and post ENSO years. The ENSO event also causes long dry season in the several parts of the Indonesian region, it means that rice planting will be very late. The isolines of rain factor of the value less than 5 covered a greater area in the ENSO year than that in the non ENSO years.

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