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Journal of Mathematical and Fundamental Sciences
Published by Institut Teknologi Bandung
ISSN : 23375760     EISSN : 23385510     DOI : https://doi.org/10.5614/j.math.fund.sci.
Core Subject : Science, Education,
Astronomy Chemistry Earth & Planetary Sciences Mathematics Physics
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.
Arjuna Subject : Matematika - Matematika (Lain-Lain)
Articles 668 Documents
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Optimization of EC Values of Nutrient Solution for Tomato Fruits Quality in Hydroponics System Using Artificial Neural Network and Genetic Algorithms Herry Suhardiyanto; Chusnul Arif; Budi I. Setiawan
Journal of Mathematical and Fundamental Sciences Vol. 41 No. 1 (2009)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.sci.2009.41.1.3

Abstract

Total soluble solids (TSS) and fruit fresh weight are two indicators to show the quality of tomato fruits. To gain high values of TSS and fruit fresh weight, it is important to consider the concentration of nutrient solution, which is commonly represented by Electrical Conductivity (EC) value. Generally, the increasing of EC value not only increases the number of TSS, but also decreases fruit fresh weight. Therefore, it is important to optimize the EC value for both indicators of quality of tomato fruits. The objective of this research is to optimize the EC value of nutrient solution on each generative stage using Artificial Neural Network (ANN) and Genetic Algorithms (GA). ANN was used to identify the relationship between different EC value treatments with TSS value and fruit fresh weight. GA was applied to determine the optimal EC value in generative growth, which is divided into three stages. Results showed that the optimal EC values in the flowering stage, the fruiting stage and the harvesting stage were 1.4 mS/cm, 10.2 mS/cm and 9.7 mS/cm, respectively.
Diffuse Neutron Scattering of KBr at Room Temperature and Its Application as Background Function in Rietveld Analysis Khairul Basar; Xianglian Xianglian; Takashi Sakuma; Haruyuki Takahashi; Naoki Igawa
Journal of Mathematical and Fundamental Sciences Vol. 41 No. 1 (2009)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.sci.2009.41.1.5

Abstract

Diffuse neutron scattering from powder KBr was measured at room temperature. The oscillatory diffuse scattering is clearly observed. The diffuse scattering theory including correlation effects among thermal displacements of atoms is applied to background function in the Rietveld analysis. The observed scattering data are analyzed by including the correlation effects among thermal displacements of first, second and third nearest neighboring atoms. The inter-atomic distance and temperature dependence of the values of correlation effects is discussed.
Analysis of the String Structure Near Break-up of A Slender Jet of An Upper Convected Maxwell Liquid A. Y. Gunawan; W. S. Budhi
Journal of Mathematical and Fundamental Sciences Vol. 41 No. 1 (2009)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.sci.2009.41.1.4

Abstract

In this paper, we analytically study the string structure near the break-up of a slender jet of a viscoelastic liquid surrounded by air. The governing equations are derived from the conservation laws of mass and momentum, and the rheological equation of the jet. The rheological equation of the jet is assumed to satisfy an Upper Convected Maxwell (UCM) model. Introducing a stretch variable and then applying a transformation, we obtain a coupled system of nonlinear differential equations. Via these equations, we then show that the UCM jet does not break up in finite time, which physically means that it has sufficient time to exhibit the string structure before it breaks up due to the dominant surface force.
On Eigenvalues and Eigenvectors of Perturbed Pairwise Comparison Matrices Pudji Astuti; Agah D. Garnadi
Journal of Mathematical and Fundamental Sciences Vol. 41 No. 2 (2009)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.sci.2009.41.2.1

Abstract

This work studied eigenvalues and eigenvectors of a class of perturbed pairwise comparison matrices (PCMs). This type of matrices arises from Analytical Hierarchical Process with inconsistency comparison. By employing some nice structures of the PCMs, we show that the object dimension of size n â‰¥ 3 can be reduced into a case of size 3, hence simplify the studies.
Structure and Properties of Polymers Prepared by Polymerization of 2,2-Dimethyl-1,3-Propandiol and ε-Caprolactone Monomer I Made Arcana; M. Hasan; Shinta Dewi Anggraini; Asti Ardhyo Febrianti; Aditya Ardana
Journal of Mathematical and Fundamental Sciences Vol. 41 No. 2 (2009)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.sci.2009.41.2.2

Abstract

Poly(ε-caprolactone) (PCL) is very attractive synthetic polymer due to its properties, such as a high permeability, the lack of toxicity, and also biodegradability. However, it has limited application because of low melting point (60 °C), high crystallinity, and brittleness. The aim of the experiments is designed to improve the properties of PCL by formation of their polymers with 2,2-dimethyl-1,3-propandiol monomers with various chain length as a raw material to prepare poly(urethane-ester). These polymers were synthesized by a ring-opening polymerization of 2,2-dimethyl-1,3-propandiol and ε-caprolactone monomers in various composition in the presence of 1-hydroxy-3-chloro-tetraisobuthyldistanoxane as a catalyst. Polymers were characterized by analysis of functional groups (FTIR), microstructure (1H and 13C NMR), viscosity, hydroxyl number, and also melting point of polymers (DSC). Based on the structure analysis indicate that polymerization of 2,2-dimethyl-1,3-propandiol and ε-caprolactone monomers produced polymers with various molecular weights, which depend on the ratio of ε-caprolactone / 2,2-dimethyl-1,3-propandiol used in polymerization. The reactivity of CL monomer decreases to the active site of polymers with longer chain size. The melting points of polymers increase with the increasing of ε-caprolactone composition used in polymerization, whereas hydroxyl number decreases.
Bioremediation of Phenanthrene, Chrysene, and Benzo[a]pyrene by Fungi Screened from Nature Tony Hadibrata; Sanro Tachibana
Journal of Mathematical and Fundamental Sciences Vol. 41 No. 2 (2009)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.sci.2009.41.2.3

Abstract

Laccase of Polyporus sp. S133 was able to oxidize most of the 3 different rings amount polycyclic aromatic hydrocarbons (PAHs) tested. Phenanthrene was removed by 89% followed by chrysene and benzo[a]pyrene which were oxidized by 66 and 55%, respectively. Addition of 1-hydroxybenzotriazole (HBT) to the reaction mixture increased oxidation of PAHs, especially phenanthrene was almost completely removed from the reaction mixture. Oxidation of chrysene and benzo[a]anthracene increased 12 and 10% with the mediator to 78 and 65% in the presence of HBT. PAH-quinones as oxidation products were formed from all PAH to different extents. A part of PAH was polymerized in the laccase/mediator system to products of weight-average molecular weight (MW). The correlation of the ionization potentials of PAH with the oxidation of these compounds is limited to the alternating PAH.
Tropical Mangrove Mapping Using Fully-Polarimetric Radar Data Bambang H. Trisasongko
Journal of Mathematical and Fundamental Sciences Vol. 41 No. 2 (2009)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.sci.2009.41.2.4

Abstract

Although mangrove is one of important ecosystems in the world, it has been abused and exploited by human for various purposes. Monitoring mangrove is therefore required to maintain a balance between economy and conservation and provides up-to-date information for rehabilitation. Optical remote sensing data have delivered such information, however ever-changing atmospheric disturbance may significantly decrease thematic content. In this research, Synthetic Aperture Radar (SAR) fully polarimetric data were evaluated to present an alternative for mangrove mapping. Assessment using three statistical trees was performed on both tonal and textural data. It was noticeable that textural data delivered fairly good improvement which reduced the error rate to around 5-6% at L-band. This suggests that insertion of textural data is more important than any information derived from decomposition algorithm.
Analyzing the Interaction of Andrographolide and Neoandrographolide, Diterpenoid Compounds From Andrographis Paniculata (Burm.F) Nees, to Cyclooxygenase-2 Enzyme by Docking Simulation Jutti Levita; Enade P. Istyastono; As'ari Nawawi; Abdul Mutholib; Iwan J. P. de Esch; Slamet Ibrahim
Journal of Mathematical and Fundamental Sciences Vol. 41 No. 2 (2009)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.sci.2009.41.2.5

Abstract

Cyclooxygenase (COX), an enzyme involved in the conversion of arachidonic acid to prostaglandins, exists in two isoforms, which are COX-1 and COX-2. Despite the similarities of COX-1 and COX-2, the two isoforms show subtle differences in amino acid composition at the active sites. Since COX-1 has isoleucine, a bulkier amino acid at position 523 than COX-2's valine, it allows COX-2 to have a larger space in its active site. Andrographolide reduces COX-2 expression induced by PAF and fMLP in HL60/neutrophils. Neoandrographolide inhibits COX-2 expression at the translational level. The purpose of this study is to examine the binding modes of andrographolide and neoandrographolide against COX-1 and COX-2 in terms of hydrogen bonds and docking energy, to understand their antiinflammatory property. The docking simulation indicates that both andrographolide and neoandrographolide are able to be located in the COX-2's binding pocket but not in the COX-1's. It confirms that COX-1's binding pocket is smaller than COX-2's. Based on this study, both andrographolide and neoandrographolide show selective inhibitory property to COX-2. Their selectivity are due to their specific interaction with Arg 513 in the binding pocket of COX-2, which is also shown by SC-558, a COX-2 selective inhibitor.
Nanolithography on the Electron Beam Resist using the Scanning Probe Microscope Cantilever Lydia Anggraini; Naoki Matsuzuka; Yoshitada Isono
Journal of Mathematical and Fundamental Sciences Vol. 42 No. 1 (2010)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.sci.2010.42.1.1

Abstract

This research demonstrates the feasibility of fabricating nanoscale resist patterns on a silicon (Si) substrate using a scanning probe microscope (SPM). In order to utilize scanning probe nanolithography (SPNL) with the other micro-machining techniques such as dry etching, plating and lift-off process, nanoscale resist patterns should be created on an Si substrate with high accuracy in SPNL. We have, so far, established the negative type of SPNL using the negative-tone electron beam (EB) resist named SAL601. The primary objective of this research is to find out appropriate process conditions for establishing the positive type of SPNL using the positive EB resist "³ZEP520A"³. This paper describes the variations of experimentally created nano-patterns depending on the process conditions, and determines the appropriate process conditions from the variations obtained. In addition, we analyzed the electric field in the EB resist by a finite element method (FEM), for estimating the line width of the nano-pattern created by SPNL.
Partial Internal Control Recovery on 1-D Klein-Gordon Systems Iwan Pranoto
Journal of Mathematical and Fundamental Sciences Vol. 42 No. 1 (2010)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.sci.2010.42.1.2

Abstract

In this exposition, a technique to recover internal control on a distributed parameter system is reported. The system is described by 1-D Klein- Gordon partial differential equation with a time-varying parameter. We would like to recover the internal control applied to the system if we know some limited information about the output. We use a method called sentinel method to recover the internal control. It involves some construction of a linear functional, and we show that this construction relates closely to the exact controllability problem.

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