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Journal of Mathematical and Fundamental Sciences
ISSN : 23375760     EISSN : 23385510     DOI : https://doi.org/10.5614/j.math.fund.sci.
Core Subject : Science, Education,
Journal of Mathematical and Fundamental Sciences welcomes full research articles in the area of Mathematics and Natural Sciences from the following subject areas: Astronomy, Chemistry, Earth Sciences (Geodesy, Geology, Geophysics, Oceanography, Meteorology), Life Sciences (Agriculture, Biochemistry, Biology, Health, Medical, Pharmacy), Mathematics, Physics, and Statistics.
Articles 689 Documents
Pemodelan Hubungan Hujan dan Aliran Permukaan pada Suatu DAS dengan Metoda Beda Hingga Dantje Kardana Natakusumah; M Syahril B. Kusuma; Hendra Darmawan; M Bagus Adityawan; M Farid
Journal of Mathematical and Fundamental Sciences Vol. 39 No. 1-2 (2007)
Publisher : Institute for Research and Community Services (LPPM) ITB

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Abstract

Hujan menimbulkan aliran di daratan, baik aliran permukaan maupun aliran di dalam tanah. Pada jurnal ini, akan dibahas mengenai perangkat lunak yang dapat digunakan untuk memodelkan aliran di permukaan. Perangkat lunak ini dikembangkan berdasarkan persamaan Saint Venant, dengan menggunakan skema pengepingan MacCormack 2D. Perhitungan limpasan permukaan terhadap waktu dilakukan untuk 5 profil permukaan tanah yang berbeda, profil datar, segitiga, parabolik, dan 2 profil alam. Pada profil yang berbentuk datar, dilakukan perbandingan solusi antara analitik dan numerik yang menunjukkan bahwa keduanya tidak jauh berbeda.
Sistem Kontrol Hibrida Sinyal Rujukan Berbasis Logika Fuzzy untuk Peningkatan Kinerja Transien Pengontrol PID Endra Joelianto; oberli tansri
Journal of Mathematical and Fundamental Sciences Vol. 39 No. 1-2 (2007)
Publisher : Institute for Research and Community Services (LPPM) ITB

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Abstract

Makalah ini membahas suatu metoda kontrol yang disebut kontrol sinyal rujukan (set-point) dengan pengambilan keputusan menggunakan logika fuzzy. Metoda ini dirancang untuk mengurangi keterbatasan sistem kontrol umpan balik yang harus mempunyai penguatan pengontrol tinggi untuk menghasilkan kinerja transien yang cepat. Metoda kontrol sinyal rujukan dapat memperbaiki kinerja transien dengan tanpa mempengaruhi karakteristik dinamik sistem kontrol lup tertutupnya. Pada makalah ini, pengontrol umpan balik yang digunakan adalah pengontrol PID dan kontrol sinyal rujukan menggunakan pengambilan keputusan dengan sistem fuzzy berdasarkan sinyal kesalahan. Kinerja metoda kontrol sinyal rujukan dengan sistem logika fuzzy dan sistem kontrol umpan balik dengan pengontrol PID diperlihatkan oleh beberapa hasil simulasi pada model umum sistem berorde satu dan dua dengan waktu mati.
Pengukuran Parameter Seismik dan Difraksi Sinar-X (XRD) pada Batuan Karbonat Formasi Parigi Jhon Alder; Bagus Endar Bachtiar Nur Handoko
Journal of Mathematical and Fundamental Sciences Vol. 39 No. 1-2 (2007)
Publisher : Institute for Research and Community Services (LPPM) ITB

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Abstract

Substitusi fluida merupakan bagian dari studi seismik untuk memodelkan dan menghitung berbagai macam skenario substitusi fluida yang memberi petunjuk pada pengamatan respon AVO (Amplitude Variation with Offset) dan data seismik post stack. Substitusi fluida melibatkan persamaan Gassmann yang akan mengestimasi efek fluida terhadap parameter modulus bulk. Prediksi parameter modulus bulk ini dapat dipakai untuk mencari keberadaan hidrokarbon.Eksperimen dilakukan terhadap beberapa sampel core batuan karbonat formasi Parigi di daerah Cirebon. Batuan karbonat yang diprediksi berkategori reef dengan kandungan mineral Calcite yang dominan. Kemudian diukur di dalam laboratorium seismik batuan tekanan tinggi dengan variasi tekanan berupa overburden dan pore pressure. Pengamatan dilakukan saat fluida berupa air disubstitusikan ke dalam batuan serta mengamati efek fluida yang terjadi ketika variasi tekanan diberikan. Pengaruh dari kehadiran fluida ini akan digunakan untuk menjelaskan efek substitusi fluida pada batuan karbonat.Kenaikan atau bertambahnya kecepatan gelombang-P ini berbanding lurus dengan modulus bulk dari fluida pengisi pori, sedangkan kecepatan gelombang-S cenderung menurun dengan kehadiran fluida. Hal ini menyatakan bahwa asumsi Gassmann tidak berlaku untuk batuan karbonat.
Kajian Biodegradasi Limbah Cair Industri Biodiesel pada Kondisi Anaerob dan Aerob Mindriany Syafila; Tjandra Setiadi; Abdul Haris Mulyadi; ESMIRALDA Esmiralda
Journal of Mathematical and Fundamental Sciences Vol. 39 No. 1-2 (2007)
Publisher : Institute for Research and Community Services (LPPM) ITB

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Abstract

Penelitian ini bertujuan untuk menangani limbah yang terjadi dari industri biodiesel. Air limbah yang dihasilkan dari industri biodiesel diperkirakan memiliki kandungan organik yang cukup tinggi. dengan demikian perlu dipertimbangkan untuk mengolahnya dengan proses anaerob, sehingga berpotensi untuk mendapatkan produk samping berupa biogas (gas metana). Namun demikian, proses aerob sebagai kelanjutan degradasi secara anaerob harus pula ditinjau, karena masih adanya kandungan organik yang tersisa setelah proses anaerob. Hasil penelitian menunjukkan bahwa efisiensi proses anaerob masih kecil yang ditunjukkan oleh hasil uji Biochemical Methane Potential (BMP) yang hanya sekitar 30%, akan tetapi dari uji Anaerobic Toxicity Assay (ATA) tampak bahwa limbah cair tidak menghambat pertumbuhan mikroorganisme metanogen. Kinerja proses aerob juga belum menunjukkan hasil yang maksimal, karena efisiensi biodegradasi baru sekitar 75-80%. Hal ini karena proses aerob seharusnya ditujukan untuk mengolah lebih lanjut efluen proses anaerob.
Arsenic and Mercury Concentrations at Several Geothermal Systems in West Java, Indonesia N. R. Herdianita; B. Priadi
Journal of Mathematical and Fundamental Sciences Vol. 40 No. 1 (2008)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.sci.2008.40.1.1

Abstract

A study at several geothermal systems in West Java, Indonesia shows that thermal waters could naturally contain up to 2.6 ppm As and 6.5 ppb Hg, and the surface hydrothermal alteration could contribute up to 50 ppm As and 800 ppb Hg. The higher the chloride content, the higher the contents of As and Hg of thermal waters. The amounts of As and Hg in an active geothermal system are influenced by the type of host rock, boiling and mixing processes, and adsorption of vapor and volcanic gases into thermal waters.
Plutonium and Minor Actinides Recycling in Standard BWR using Equilibrium Burnup Model Abdul Waris; Rizal Kurniadi; Zaki Su'ud
Journal of Mathematical and Fundamental Sciences Vol. 40 No. 1 (2008)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.sci.2008.40.1.2

Abstract

Plutonium (Pu) and minor actinides (MA) recycling in standard BWR with equilibrium burnup model has been studied. We considered the equilibrium burnup model as a simple time independent burnup method, which can manage all possible produced nuclides in any nuclear system. The equilibrium burnup code was bundled with a SRAC cell-calculation code to become a coupled cell-burnup calculation code system. The results show that the uranium enrichment for the criticality of the reactor, the amount of loaded fuel and the required natural uranium supply per year decrease for the Pu recycling and even much lower for the Pu & MA recycling case compared to those of the standard once-through BWR case. The neutron spectra become harder with the increasing number of recycled heavy nuclides in the reactor core. The total fissile rises from 4.77% of the total nuclides number density in the reactor core for the standard once-through BWR case to 6.64% and 6.72% for the Plutonium recycling case and the Pu & MA recycling case, respectively. The two later data may become the main basis why the required uranium enrichment declines and consequently diminishes the annual loaded fuel and the required natural uranium supply. All these facts demonstrate the advantage of plutonium and minor actinides recycling in BWR.
P-, I-, g-, and D-Angles in Normed Spaces Hendra Gunawan; Janny Lindiarni; Oki Neswan
Journal of Mathematical and Fundamental Sciences Vol. 40 No. 1 (2008)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.sci.2008.40.1.3

Abstract

The notion of angles is known in a vector space equipped with an inner product, but not well established in a vector space equipped only with a norm. In this note, we shall develop some notions of angles between two vectors in a normed space and discuss their properties.
The Synthesis of Imidazoline Derivative Compounds as Corrosion Inhibitor towards Carbon Steel in 1% NaCl Solution Deana Wahyuningrum; Sadijah Achmad; Yana Maolana Syah; Buchari Buchari; Bambang Ariwahjoedi
Journal of Mathematical and Fundamental Sciences Vol. 40 No. 1 (2008)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.sci.2008.40.1.4

Abstract

Oleic imidazoline is one of the nitrogen containing heterocyclic compounds that has been widely used as commercial corrosion inhibitor, especially in minimizing the carbon dioxide induced corrosion process in oilfield mining. In this present work, some imidazoline derivative compounds have been synthesized utilizing both conventional and microwave assisted organic synthesis (MAOS) methods, in order to determine their corrosion inhibition properties on carbon steel surface. The MAOS method is more effective in synthesizing these compounds than the conventional method regarding to the higher chemical yields of products (91% to 94%) and the shorter reaction times (7 to 10 minutes). The characterization of corrosion inhibition activities of the synthesized products towards carbon steel in 1% NaCl solution was determined by the Tafel plot method. The corrosion inhibition activities of compound 1b ((Z)-2-(2-(heptadec-8-enyl)-4,5-dihydroimidazol-1-yl)ethanamine), 2b ((Z)-2-(2-(heptadec-8-enyl)-4,5-dihydroimidazol-1-yl)ethanol) and 3b (2-(2-heptadecyl-4,5-dihydroimidazol-1-yl)ethanamine) at 8 ppm concentration in 1% NaCl solution are, respectively, 32.18%, 39.59% and 12.73%. The heptadec-8-enyl and hydroxyethyl substituents at C(2) and N(1) position of imidazoline ring, respectively, gave the most effective corrosion inhibition activity towards carbon steel compared to the presence of other substituents. The increase in concentrations of compound 1b, 2b and 3b in 1% NaCl solution tends to improve their corrosion inhibition activities. Based on the analysis of the free Gibbs adsorption energy (ÄG0ads) values of compound 1b, 2b and 3b (-32.97, -34.34 and -31.27 kJ/mol, respectively), these compounds have the potential to interact with carbon steel through semi-physiosorption or semi-chemisorption.
The Chemical Compositions of Thermal Waters at Ciarinem and Cilayu, Pameungpeuk, West Java - Indonesia N. R. Herdianita; B. Priadi
Journal of Mathematical and Fundamental Sciences Vol. 40 No. 1 (2008)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.sci.2008.40.1.5

Abstract

Thermal waters at Ciarinem and Cilayu, Pameungpeuk, West Java, Indonesia have different characteristics: Ciarinem water is a steam heated sulfate type and occurs as hot springs, whereas Cilayu water discharges as hot pools and is a chloride water type. Their chemical compositions indicate that the thermal waters are outflows of a volcanic"“magmatic associated geothermal system. The solute geothermometers calculate that the subsurface reservoir temperatures range from 150o to 200ºC.
Synthesis of Fe–Li–Cr Multinuclear Complexes as Molecular Magnet Materials Djulia Onggo; Iis Siti Jahro; Fahimah Martak; Ismunandar Ismu
Journal of Mathematical and Fundamental Sciences Vol. 40 No. 1 (2008)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.sci.2008.40.1.6

Abstract

Multinuclear complexes have received considerable interest as molecular magnet materials. Up to now, several complex compounds based on bidentate ligand 2,2' bipyridine have been synthesized. In this research, the Fe-Li-Cr multinuclear complexes with derivative 2'2- bipyridine ligands: 2-(2'-pyridyl)quinoline(pq), 2,2'-Pyridil(pdl) have been synthesized. The oxalate (ox) ligand has also been used as a bridging ligand in these multinuclear complexes. The chemical formula of Li[FeCr(ox)2(pq)(BF4)2(H2O)2] and [Fe(pdl)n][LiCr(ox)3] complexes have been verified using metal and C, H, N elemental analysis data. The IR spectra in 350 "“ 4000 cm-1 range exhibit characteristic absorptions, which support the proposed structure of complex. The plausible structure of the compounds has been drawn based on complex formation mechanism. The magnetic susceptibility at room temperature of the pq-complex is about 5.7 BM and of the pdl- complexes are 4.8 and 5.5 BM. These indicated that both spin states of iron(II) exist in the multinuclear complexes.

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