cover
Article Per Year (5 Year)
All
Home Page
OAI Link
Editorial Team
Contact
Reviewer
Google Scholar
Contact Name
-
Contact Email
-
Phone
-
Journal Mail Official
-
Editorial Address
-
Location
Kota bandung,
Jawa barat
INDONESIA
Jurnal Matematika & Sains
Published by Institut Teknologi Bandung
ISSN : -     EISSN : -     DOI : -
Core Subject : Education,
Mathematics
Arjuna Subject : -
Articles 339 Documents
 14   15   16   17   18 
Asymmetric Addition Reaction of Reformatsky Type Reagent to Nitrones: An Intermediate for Synthesis of Physiologically Active Substances Deana Wahyuningrum
Jurnal Matematika & Sains Vol 9, No 4 (2004)
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Asymmetric addition reaction of Reformatsky type reagent, which was generated in situ from diethylzinc and iodoacetic ester, to carbon-nitrogen double bond in nitrones utilizing (R,R)-DIPT as a chiral auxiliary agent showed fairly moderate to high enantioselective products in fairly high chemical yields. Nitrones were known as one of potentially intermediate nitrogen-containing compounds for synthesizing/physiologically active substances, such as pharmaceutical and agrochemical substances. The best results of this type of reaction were achieved from the asymmetric addition to nitrone, 6,7-dimethoxy-3,4-dihydroisoquinoline N-oxide (73% ee) and N-phenyl-α-(dibenzylcarbamoyl)methanimine N-oxide (21% ee) with fairly high chemical yields. The use of additive in asymmetric addition reaction to 6,7-dimethoxy-3,4-dihydroisoquinoline N-oxide was found to be crucial in improving the enantioselectivity of reaction, since the best results mentioned were achieved in the presence of isoquinoline-N-oxide or pyridine-N-oxide (0.5 molar equivalent) as additive. The difference in stereo-structure between 6,7-dimethoxy-3,4-dihydroisoquinoline N-oxide and N-phenyl-α-(dibenzylcarbamoyl)methanimine N-oxide caused the effect of (R,R)-DIPT as chiral auxiliary agent, additives and slow charge addition method towards the course of reaction resulting different products with different enantioselectivity.
Recalculating the Orbit of α-Centauri AB Suryadi Siregar; Hanindyo Kuncarayakti
Jurnal Matematika & Sains Vol 12, No 3 (2007)
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

The two main components of the closest star system, α Centauri AB (RA 14h39m, Dec -60o50, J2000.0) is indubitablyone of the most studied visual double stars. This paper presents the results of our recalculation of orbital and physicalparameters of the system using Thiele-van den Bos method, based on observational data from year 1900 to 2002.Despite some significant discrepancies, in general our results confirmed previous results of orbital parameterdeterminations using different method.
Studi Pengaruh Rasio Masukan Sumber V/III Terhadap Distribusi Sb dan Karakteristik Kelistrikan Lapisan Tipis GaAs1-x Sbx yang Ditumbuhkan dengan Teknik MOCVD [On the Study of the Effect of Source Input V/III to the Distribution of Sb and Electricity.....] Andi Suhandi; Pepen Arifin; Maman Budiman; Muhamad Barmawi
Jurnal Matematika & Sains Vol 12, No 3 (2007)
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

The study of the dependence of the Sb distribution in GaAs1-xSbx films and the electric properties of the GaAs1-xSbx filmsgrown by MOCVD technique using TMGa, TDMAAs, and TDMASb to the V/III source input ratio has been done. The Sbsolid composition in GaAs1-xSbx film was determined by using Vegards law from the shift of the peak intensity of X-raydiffraction pattern. Electric properties of the GaAs1-xSbx films were investigated through room temperature Hall effectmeasurement. The results suggest that the concentration of Sb incorporation into the GaAs1-xSbx films is stronglyaffected by V/III source input ratio. For V/III source input ratio of unity, the Sb distribution coefficient, which is theratio of the Sb composition in GaAs1-xSbx solid to the Sb vapor input mole fraction, is nearly unity. The Sb distributioncoefficient decreases with increasing of V/III source input ratio, for V/III input ratio langer than 1. The range of carriermobility are between 200 – 430 cm2/V.s, depending on the V/III input ratio, and the Sb composition. The highest carriermobility occurred at V/III input ratio of approximately one.
Ekstraksi dan Pemisahan Penisilin G dari Fenilasetat dengan Teknik Membran Cair Emulsi Imam Santoso; Buchari Buchari; Muhammad Bachri Amran; Aminudin Sulaeman
Jurnal Matematika & Sains Vol 12, No 3 (2007)
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

The separation and purification of penicillin G from phenyl acetic acid (PAA) is very difficult to be carried out becausethe two compounds are weak acids and the two compounds can change from one to another by influence of pH. The aimof this research is to establish the optimal conditions for the extraction and separation of penicillin G from phenylaceticacid using the emulsion liquid membrane technique. The optimal conditions were ratio of internal phase volume tomembrane phase volume of 1:1; time of stiring for emulsion preparation of 1 minute; emulsion contact rate of 300 rpm;emulsion contact time of 15 minutes; rate of stirring of emulsion of 2000 rpm; rest time of emulsion of 13 minutes;concentration of penicillin G as external phase 375 ppm; and concentration of surfactant 5% (v/v). At these conditionspenicillin G can be extracted and separated from phenylacetic acid with a separation factor of 19.3 and a contact timeof 15 minutes. Thus the technique of emulsion liquid membrane may be used as a reasonably effective method toseparate penicillin G from phenylacetic acid.
Konsumsi Oksigen, Kadar Hb Darah, Dan Pertumbuhan Ikan Mas, Cyprinus carpio, Diberi Pakan Campuran Ampas Kelapa Darmadi Goenarso; Suripto Suripto; K I Susanthi
Jurnal Matematika & Sains Vol 8, No 2 (2003)
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

A laboratory experiment on carp (Cyprinus carpio) given a shredded coconut mixed diet has been conducted. Carp aged 4 – 5 months (n = 50; weight = 24,46-25,78 g), were kept individually in each aquarium (50x30x30 cm). The waste shredded coconut was mixed with commercial fish feed. Five concentrations (w/w) of mixed diet were given as treatment, i.e.: 30% (P30), 40% (P40), 50% (P50), and 60% (P60). Controlled fish was only given commercial feed. The experiment was done within 10 weeks with five replicates. Fish were fed twice daily as much as 10% of body weight. Measurements on oxygen consumption rate and body weight were done weekly. The fish were kept from food for 24 hours prior to measurements. The hemoglobin concentration was measured at the beginning and at the end of the experiment only. ANOVA was used for statistical tests. Results showed that the oxygen consumption rate of the treated fish was not different from the controlled fish. Relative growth rate decreased significantly. The average growth rate of fish treated with P30, P40, P50, P60, were respectively 0.042%, 0.041%, 0.031% and 0.018%. Growth rate of controlled fish was 0.104%. There was n o difference on the hemoglobin concentration measured at the end of the experiment (7.89 mg/dl) compared to the value at the start (7.91 mg/dl) of the experiment. It can be concluded that waste shredded coconut mixed diet might be used as fish feed. However, some improvements should be done on the composition of nutrition in the diet to increase the fish growth rate.
Peranan Pengelompokan Samar dalam Prediksi Kekeringan di Indonesia Berkaitan dengan ENSO dan IOD The Houw Liong; Bannu Bannu; P M Siregar
Jurnal Matematika & Sains Vol 8, No 2 (2003)
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

In general drought in Indonesia can be predicted from intensities of El Nino that can be defined by using time series of sea surface anomaly on Pacific Ocean (SSTA 3.4). It can be shown that when El Nino with strong intensities occur then more than 65% regions in Indonesia the precipitations are below normal (drought in Indonesia). The correlation between strong El Nino intensities and percentages of regions in Indonesia with precipitations below normal are high, but when the intensities are weak the correlations are low. In this case other phenomena such as on Indian Ocean Dipole Mode (IOD) can contribute to drought in Indonesia. Clustering of climatic regions in Indonesia based on monthly rainfall pattern using fuzzy set, fuzzy relations or Kohonen’s neural network will help to clarify drought on these regions. It can be shown that climatic regions in Indonesia can be clustered based on monthly rainfall patterns that are strongly influence by Australian monsoon which is known as North Australia Indonesian Monsoon (NAIM) and Maritime Continent (MC) which has equatorial precipitation characteristic. The climatic clustering is based on the ground that ENSO and IOD are regional atmospheric dynamic so the clustering should be based on average monthly pattern or geopotential height. The east MC and NAIM will be influence strongly by ENSO and the western MC especially south Sumatra and west Java is influence also by IOD.
Intramolecular Forces Density in Mesophilic and Thermophilic Proteins: Amino Acid Clusters Based Study Rukman Hertadi; Minoru Kanehisa
Jurnal Matematika & Sains Vol 12, No 3 (2007)
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Thermostability of (hyper)thermophilic enzymes has been taken as an advantage in industry to enhance biochemicalreactions at elevated temperature. Factors responsible for the thermostability in this class of proteins, however, stillremain unclear despite the many works that have been done to elucidate such factors by performing variouscomparative studies to homologous pairs of (hyper)thermophilic and mesophilic proteins. In the current work, weelucidated the factors by comparing intramolecular forces density in tertiary structure of mesophilic and(hyper)thermophilic proteins in terms of the content of various types of amino acid clusters. A graph spectral methodwas employed to probe the charged, hydrophobic and aromatic clusters in each tertiary structure of all classes ofthermophilic proteins used in our study. Our results revealed that mesophilic and (hyper)thermophilic proteins containsimilar level of all types of amino clusters, thereby stabilized with similar level of high-density intramolecular forces,but the former contain a higher number of non-cluster residues and less stabilized by electrostatic interactions, therebymore sensitive to heat.
Pengaruh Variasi Berat Molekul Polietilen Glikol terhadap Sifat Mekanik Poliuretan Eli Rohaeti; N M Surdia
Jurnal Matematika & Sains Vol 8, No 2 (2003)
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Synthesis of polyurethane was carried out by using diisocyanate monomer, (methylene-4,4’-diphenyldiisocyanate (MDI) and polyether monomer polyethylene glycol (PEG). The synthesis of polyurethane was undertaken by varying the molecular weight of PEG. The effect of molecular weight of PEG on the mechanical properties of polyurethane was observed. The variation of molecular weight of PEG was 200, 400, and 1000. Polymerization reaction was carried out at room temperature with a mol ratio of MDI to PEG was 1.17. The mechanical properties of polyurethane were characterized using AGS-500D Shimadzu tensile testing machine, with a cross head speed of 50 mm/minutes. The tensile test showed that increasing molecular weight of PEG used in the synthesis of polyurethane resulted in decreasing of the tensile strength at break of polyurethane, and increasing of elongation at break. The elasticity modulus was 92.21 kPa for polyurethane based on PEG 200; 8.96 kPa for polyurethane based on PEG 400; and 0.27 kPa for polyurethane based on PEG 1000.
Oligomer Resveratrol dari Kulit Batang Shorea assamica Dyer (Dipterocarpaceae) dan Sitotoksitasnya Sahidin Sahidin; Euis Holisotan Hakim; Yana Maolana Syah; Lia Dewi Juliawaty; Sjamsul Arifin Achmad; Nordin Hj Lajis
Jurnal Matematika & Sains Vol 12, No 3 (2007)
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Four resveratrol oligomers which consist of two resveratrol trimers, i.e., vaticanol A (1) and α-viniferin (2), and two resveratrol tetramers, i.e., vaticanol B (3), and isohopeafenol (4) have been isolated from acetone extract of the stem bark of Shorea assamica Dyer. The elucidations on the structure of these four compounds were based on the spectroscopic data, including UV, IR, 1-D and 2D NMR spectra, and comparison with related data reported previously. Cytotoxicity of the isolated compounds against murine leukemia P-388 cells exhibited that vaticanol A (1), α-viniferin (2), vaticanol B (3) dan isohopeaphenol (4) had IC50 of 27.0, 17.5, 46.4, and 36.0 ppm, respectively. The results showed that cytotoxicity of resveratrol trimers were relatively higher than resveratrol tetramers.
Fractional Integral Operators and Their Boundedness on Various Spaces Hendra Gunawan; Idha Sihwaningrum
Jurnal Matematika & Sains Vol 12, No 4 (2007)
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

This is a survey paper which presents and discusses some results on fractional integral operators and their generalizedversion on both homogeneous and non-homogeneous spaces.

Page 16 of 34 | Total Record : 339

 14   15   16   17   18 

Filter by Year

1996 2017


Reset
Filter By Issues
All Issue Vol 22 No 1 (2017) Vol 21 No 1 (2016) Vol 20 No 1 (2015) Vol 19 No 3 (2014) Vol 19 No 2 (2014) Vol 19 No 1 (2014) Vol 18 No 3 (2013) Vol 18 No 2 (2013) Vol 18, No 1 (2013) Vol 17, No 3 (2012) Vol 17, No 2 (2012) Vol 17, No 1 (2012) Vol 16, No 3 (2011) Vol 16, No 2 (2011) Vol 16, No 1 (2011) Vol 15, No 3 (2010) Vol 15, No 2 (2010) Vol 15, No 1 (2010) Vol 14, No 4 (2009) Vol 14, No 3 (2009) Vol 14, No 2 (2009) Vol 14, No 1 (2009) Vol 13, No 4 (2008) Vol 13, No 3 (2008) Vol 13, No 2 (2008) Vol 13, No 1 (2008) Vol 12, No 4 (2007) Vol 12, No 3 (2007) Vol 12, No 2 (2007) Vol 12, No 1 (2007) Vol 11, No 4 (2006) Vol 11, No 3 (2006) Vol 11, No 2 (2006) Vol 11, No 1 (2006) Vol 10, No 4 (2005) Vol 10, No 3 (2005) Vol 10, No 2 (2005) Vol 10, No 1 (2005) Vol 9, No 4 (2004) Vol 9, No 3 (2004) Vol 9, No 2 (2004) Vol 9, No 1 (2004) Vol 8, No 4 (2003) Vol 8, No 3 (2003) Vol 8, No 2 (2003) Vol 8, No 1 (2003) Vol 7, No 2 (2002) Vol 7, No 1 (2002) Vol 6, No 2 (2001) Vol 6, No 1 (2001) Vol 5, No 2 (2000) Vol 5, No 1 (2000) Vol 4, No 2 (1999) Vol 4, No 1 (1999) Vol 3, No 2 (1998) Vol 3, No 1 (1998) Vol 2, No 2 (1997) Vol 2, No 1 (1997) Vol 1, No 2 (1996) Vol 1, No 1 (1996) More Issue