Journal of Mathematical and Fundamental Sciences
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Developing Information System on Lunar Crescent Observations
Get PDFWe present a progress report on the development of information system of lunar crescent astronomical observations which will be largely accessible for public domain. This consists of calculations of the Moon's ephemeris as well as systematic real-time lunar crescent observations. A well suited small telescope, equipped with a simple digital detector, is connected to a server to provide information on lunar crescent observations. The system has been used and worked well. The only constraint is poor weather condition. Network of small telescopes, installed at various locations in Indonesia, are currently planned to provide plethora of data. In the long term, this will be used to help to determine the astronomical visibility criteria of lunar crescent for Islamic calendar
Integral Operator Defined by k-th Hadamard Product
Get PDFWe introduce an integral operator on the class A of analytic functions in the unit disk involving k Æ’{ th Hadamard product (convolution) corresponding to the differential operator defined recently by Al-Shaqsi and Darus. New classes containing this operator are studied. Characterization and other properties of these classes are studied. Moreover, subordination and superordination results involving this operator are obtained
Quivers of Bound Path Algebras and Bound Path Coalgebras
Get PDFAlgebras and coalgebras can be represented as quiver (directed graph), and from quiver we can construct algebras and coalgebras called path algebras and path coalgebras. In this paper we show that the quiver of a bound path coalgebra (resp. algebra) is the dual quiver of its bound path algebra (resp. coalgebra)
Hierarchically Porous ZSM-5 Synthesized by Nonionic- and Cationic-Templating Routes and Their Catalytic Activity in Liquid-Phase Esterification
Get PDFHierarchically porous MFI zeolites (ZSM-5) have been synthesized by hydrothermal treatment in the presence of trialkoxysilylated-derivatives of nonionic poly(oxyethylene) alkyl ether or alkyl quaternary ammonium cation as mesopore-generating agent, along with tetrapropylammonium cation as zeolite structure-directing agent. Powder X-ray diffraction revealed that zeolites have been crystallized, and scanning electron microscopy showed rugged surface morphology that was quite different from conventional ZSM-5. The mesoporosity was confirmed by nitrogen adsorption-desorption measurement showing type IV isotherms with narrow distribution of mesopore diameters. The catalytic activity of these mesoporous ZSM-5 was tested in liquid-phase esterification of benzyl alcohol with hexanoic acid. The conversion of benzyl alcohol on mesoporous ZSM-5 prepared via cationic-templating route was almost 100%, being much higher than on mesoporous ZSM-5 prepared with silylated nonionic surfactant as well as on conventional ZSM-5 with no mesopores. The presence of Brønsted acid sites, together with the mesopores, was responsible for this catalytic conversion, as confirmed by pyridine adsorption monitored by in situ infrared and 27Al magic angle spinning nuclear magnetic resonance spectroscopy
Trajectory Following Method on Output Regulation of Affine Nonlinear Control Systems with Relative Degree not Well Defined
Get PDFThe problem of output regulation of affine nonlinear systems with the relative degree not well defined by modified steepest descent control is studied. The modified steepest descent control is a dynamic feedback control which is generated by the trajectory following method. By assuming the system is minimum phase, output of the system can be regulated globally asymptotically
On Effective Locations of Catalytic Active Sites in Phase Boundary Catalysts
Get PDFZeolite loaded with alkylsilane-covered titanium oxide was found to be more effective than its nonporous silica counterpart as phase-boundary catalyst (PBC) to promote epoxidation of alkenes with aqueous hydrogen peroxide. It was demonstrated that the phase-boundary catalyst system required neither stirring to make an emulsion, nor addition of a cosolvent to make a homogeneous solution to drive the reaction. However, some basic facts about them remain unclear, such as the question as to where an effective location of the active sites of PBC resides: is it on the external surface of the catalysts, or in their pores? In order to elucidate this problem, TS-1, HZSM-5 and zeolite loaded with alkylsilane"“covered sulfonic acid in which the location of the active sites is mainly inside the pore system, were chosen as model catalysts. Catalytic activities of the catalysts TS-1 and HZSM-5 were examined after modification with n-octadecyltrichlorosilane (ODS). Their activities were compared with zeolite loaded with alkysilane-covered titanium oxide particles, in which the active sites are on the external surface in reactions of 1-octene with aqueous H2O2 and cyclohexene with water as model reactions. The study suggests that the location of the active sites on the external surface plays an important role in the phenomenon of phase-boundary catalysis
Kultur Campuran dan Faktor Lingkungan Mikroorganisme yang Berperan dalam Fermentasi âTea-Ciderâ
Get PDFTea is agricultural product containing beneficial substances, especially used for human health. The study of "Tea-cider" fermentation has been conducted using batch culture method. The purposes of the study were to observe mixed microbial culture which were actively involved in the process of "Tea-cider" fermentation, to determine the optimum fermentation conditions, as well as to evaluate the inhibition effect of the product against pathogenic bacteria. The study was carried out in two steps. Firstly, the isolation of microorganisms from "Tea-cider"; secondly producing "Tea-cider" using mixed microbial culture isolated from "Tea-cider" and "Tea-cider" itself as inoculum. Type and concentration of inoculum were optimized for the fermentation process. Mixed of the pure culture of isolated microorganisms with variation of initial cell at ratio B : K1 : K2 = 1 : 1 : 1, 3 : 1 : 1 and 5 : 1 : 1 while the variation of inoculum were 5%, 10%, and 15% (v/v). Optimization in temperature, pH and sugar concentration at the variation of temperature 250C, 280C, 300C, and 350C, pH of 4, 5, and 6, and sugar concentration 5%, 10%, and 15% (w/v) respectively. The pH, acid concentration, reducing sugar concentration and alcohol concentration were analized at 48 hours interval during 14 days fermentation. The product was tested for antimicrobial effect using agar diffusion method and for organoleptic. The result showed that mixed microbial culture which were actively involved in "Tea-cider" fermentation were yeast Schizosaccharomyces pombe (K1) dan Brettanomyces sp (K2), and a species af aceticacid Acetobacter xylinum (B). The optimum condition of "Tea-cider" fermentation were as follows, the ratio of B : K1 : K2 optimum mixed culture inoculum at 5 : 1 : 1 and 10% (v/v) for the inoculum. The incubation temperature was 300C, the medium initial pH was 5 and the intial sugar concentration was 10% (w/v). The "Tea-cider" product was able to inhibit the growth of some pathogenic bacteria such as Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli and had a good preferred taste
Studi Pengembangan Model Turbulen κ-ε untuk Sirkulasi Arus I: Aliran Dua Dimensi pada Sebuah Tampungan Air
Get PDFThis paper present the results of the κ-ε model development for simulating two dimensions flow in a small reservoir. The study was aimed to see wether the turbulent component could be better accounted by using the κ- ε model. The numerical model was developed using finite difference method where hydrodynamic equation was solved by the combination of Mc Cormack and splitting methods. The mirror method is used as the boundary condition of the model.Comparison study were done by using the field measurement result on fishery ponds and model results by other methods. Better agreement is found between field measuremenst and model results due to the increasing accuracy in turbulent model prediction
Biodegradation of Poly(R,S)-β-hydroxybutyrate and its copolymer with δ-Valerolactone Synthesized by Aluminoxane Catalyst
Get PDFPoly(R,S)-β-hydroxybutyrate (PHB) and its copolymers with δ-valerolactone were synthesized by ring-opening copolymerization of (R,S)-β-butyrolactone (β-BL) and δ-valerolactone (δ-VL) monomers in the presence of a tetraisobutyldialuminoxane catalyst. The biodegradability of these polymers by using activated sludge was studied in an aerobic medium. The objective of this work was to determine the influence of structure and crystallinity of polymers on their degree of biodegradation and initial degradation rate. It was shown that the degradation rate for bacterial P(R)-HB with 100 % (R) isotactic structure was the highest and the final biodegradation was reached around 94 % after incubation time of 35 days. Whereas the final biodegradation about 88 % was obtained for atactic P(R,S)-β-HB synthesized by using aluminoxane catalyst. The influence of the structure and crystallinity on the initial biodegradation rate were observed for the copolymers in various composition of comonomers. All these copolymers with the PHB ratio more than 10 % exhibit highly degree of biodegradation, about 85 % after 35 days of incubation time
Pengukuran Medan Magnet Lemah Menggunakan Sensor Magnetik Fluxgate dengan Satu Koil Pick-Up
Get PDFA magnetic sensor has been developed for measuring a very low magnetic field. The sensor consists of two primary coils (excitation coil) and one secondary coil (pick-up coil). Primary coil that wound at ferromagnetic core is made symmetry each other. Whereas secondary coil is wound to both of cores. Primary coil drives the core until it saturated. The generated magnetic field from excitation have the contrary direction, so if there is no external magnetic field, the magnetic field inside the secondary coil is symmetry, but if there is an external magnetic field, there will be magnetic field changes inside secondary coil. These changes will induce secondary coil, as a consequence, there will be an induction voltage that acts as signal at the ends of secondary coil. The signal is then differentiated, amplified, inserted to controlled rectifier, integrated, and amplified for the last time. From measurement results, it can be obtained that magnetic sensor can measure magnetic field in the range of measurement from -40 μT to 40 μT, with sensitivity about 346.47 mV/μT and relative error less than 4%