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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 9 Documents
Search results for , issue "Vol. 48 No. 1 (2016)" : 9 Documents clear
Oligocene Cyclic Sedimentation Deduced from Taphonomic Analysis of Molluscs in Lacustrine Deposits of the Pematang Group, Pesada Well, Central Sumatra Basin Aswan Aswan; Satia Graha; Dodi Suryadi; Taufan Wiguna; Sri Iman Qivayanti
Journal of Mathematical and Fundamental Sciences Vol. 48 No. 1 (2016)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.math.fund.sci.2016.48.1.7

Abstract

The Oligocene cycle of Pesada Well, Central Sumatra Basin, Indonesia is composed of a deepening-upward series of depositional cycles in a lacustrine environment affected by oscillations of the water level. Taphonomic analysis of gastropod molluscs was used to interpret the cycle architecture of the Brown Shale (Pematang Group). Four types of shell concentrations were identified. The early transgressive deposit has a distinct erosion surface at the base, contains concretions, is formed of coarse-grained sediment with abraded and broken shells, and is interpreted as reworked deposits. The late transgressive deposit contains a hiatal concentration formed by continuing lake level rise, with many complete shells preserved in life position. The maximum transgressive deposit has complete shells in life position or that have been transported, as well as juvenile molluscs and broken shells. The early regressive deposit contains alternating shell-rich and shell-poor layers. Since the lacustrine system shows no tectonic effects and also no marine influenced indications, the seven sedimentary cycles identified in the Pesada Well are likely to have been affected by oscillations between monsoonal and dry periods.
Growth Rates Analysis of Porites Corals from Nusa Penida, Bali Camellia Kusuma Tito; Agus Setiawan; Sri Yudawati Cahyarini; Muji Wasis Indriyawan
Journal of Mathematical and Fundamental Sciences Vol. 48 No. 1 (2016)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.math.fund.sci.2016.48.1.2

Abstract

The annual growth of Porites coral is represented by a pair of high- and low-density bands. Environmental changes in the ambient waters influence the pattern of these annual density bands. Five colonies of Porites corals from Nusa Penida, Bali were investigated to analyze their annual linear growth rates using coral densitometry. From the analysis it was found that the annual linear growth rates of the colonies varied between 0.8924 to 1.0012 cm/yr. The trends of the colonies growth rates also varied. Two colonies showed a decreasing trend, while the others showed an increasing trend. The annual linear growth rates of most of the colonies were notinfluenced by sea surface temperature (SST); only one out of five colonies had a significant correlation with SST (R = 0.66, p-value < 0.05).
Microwave Absorbing Properties of Ba0.6Sr0.4Fe12-zMnzO19 (z = 0 – 3) Materials in XBand Frequencies Yohanes Edi Gunanto; Eric Jobiliong; Wisnu Ari Adi
Journal of Mathematical and Fundamental Sciences Vol. 48 No. 1 (2016)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.math.fund.sci.2016.48.1.6

Abstract

Ba0.6Sr0.4Fe12-zMnzO19 (z = 0,1,2, and 3) were successfully synthesized by solid state reaction through a mechanical milling method. Stoichiometric quantities of analytical-grade MnCO3, BaCO3, Fe2O3, and SrCO3 precursors with purity greater than 99% were mixed. It was found that the best phase composition, having an absorber with high performance, was Ba0.6Sr0.4Fe11MnO19. Refinement of the X-ray diffraction patterns revealed that the Ba0.6Sr0.4Fe11MnO19 was single-phase and had a hexagonal structure (P63/mmc). Mechanical milling of Ba0.6Sr0.4Fe11MnO19 powders produced particles with a mean size of ~850 nm. SEM images revealed the morphology of the particles as being aggregates of fine grains. The magnetic properties of the Ba0.6Sr0.4Fe11MnO19 particles showed a low coercivity and a high remanent magnetization. The Ba0.6Sr0.4Fe11MnO19 has certain microwave absorber properties in the frequency range of 8-14 GHz, with an absorbing peak value of "‘8 dB and -10 dB at frequencies of 8.5 and 12.5 GHz, respectively. The study concludes that the Ba0.6Sr0.4Fe12-zMnzO19 that was successfully synthesized is a good candidate for use as an electromagnetic absorber material.
Influence of Various Precursor Compositions and Substrate Angles on ZnO Nanorod Morphology Growth by Aqueous Solution Method Puenisara Limnonthakul; Daw Yangnoi; Patamas Bintachitt; Manoch Hengwattana; Mati Horprathum
Journal of Mathematical and Fundamental Sciences Vol. 48 No. 1 (2016)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.math.fund.sci.2016.48.1.5

Abstract

ZnO nanorods were synthesized on silicon wafer substrate with a seed zinc layer using the aqueous solution method. The influence of various precursor compositions on the morphology of the ZnO nanorods, with substrate angles at 0° and 90°, was investigated. The various ratios of hexamethylenetetramine in zinc nitrate hexahydrate were used as precursors in the synthesis of ZnO. Scanning electron micrography indicated that the growth of the ZnO nanorods with a 0° substrate angle was smaller than with a 90° substrate angle. The substrate angle is defined as the angle between the plane of the substrate and the horizontal layer of an aqueous solution. When the precursor concentration of hexamethylenetetramine is not equal to the ratio corresponding to the chemical reaction, the effect of the substrate angle on the diameter size and morphology of the ZnO nanorods is evident. Grazing incident X-ray diffraction (GIXRD) was used to characterize the structure of all samples. The diffraction patterns showed that the orientation matched the hexagonal wurtzite structure.
Trees with Certain Locating-chromatic Number Dian Kastika Syofyan; Edy Tri Baskoro; Hilda Assiyatun
Journal of Mathematical and Fundamental Sciences Vol. 48 No. 1 (2016)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.math.fund.sci.2016.48.1.4

Abstract

The locating-chromatic number of a graph G can be defined as the cardinality of a minimum resolving partition of the vertex set V(G) such that all vertices have distinct coordinates with respect to this partition and every two adjacent vertices in G are not contained in the same partition class. In this case, the coordinate of a vertex v in G is expressed in terms of the distances of v to all partition classes. This concept is a special case of the graph partition dimension notion. Previous authors have characterized all graphs of order n with locating-chromatic number either n or n-1. They also proved that there exists a tree of order n, n≥5, having locating-chromatic number k if and only if k âˆˆ{3,4,"¦,n-2,n}. In this paper, we characterize all trees of order n with locating-chromatic number n - t, for any integers n and t, where n > t+3 and 2 ≤ t < n/2.
Approximate Solutions of Linearized Delay Differential Equations Arising from a Microbial Fermentation Process Using the Matrix Lambert Function Agus Yodi Gunawan; Kasbawati Kasbawati; Kuntjoro Adji Sidarto
Journal of Mathematical and Fundamental Sciences Vol. 48 No. 1 (2016)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.math.fund.sci.2016.48.1.3

Abstract

In this paper we present approximate solutions of linearized delay differential equations using the matrix Lambert function. The equations arise from a microbial fermentation process in a metabolic system. The delay term appears due to the existence of a rate-limiting step in the fermentation pathway. We find that approximate solutions can be written as a linear combination of the Lambert function solutions in all branches. Simulations are presented for three cases of the ratio of the rate of glucose supply to the maximum reaction rate of the enzyme that experienced delay. The simulations are worked out by taking the principal branch of the matrix Lambert function as the most dominant mode. Our present numerical results show that the zeroth mode approach is quite reliable compared to the results given by classical numerical simulations using the Runge-Kutta method.
Effect of V Dopant on Physicochemical Properties of Vanadium-Doped Anatase Synthesized via Simple Reflux Technique Hari Sutrisno; Ariswan Ariswan; Dyah Purwaningsih
Journal of Mathematical and Fundamental Sciences Vol. 48 No. 1 (2016)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.math.fund.sci.2016.48.1.8

Abstract

Mesoporous pure TiO2 (M-TiO2) and mesoporous-vanadium-doped TiO2 (M-V-doped TiO2) were successfully synthesized via a facile and simple reflux technique. The purpose of this research was to study the effect of vanadium dopant on the physicochemical properties of all materials obtained. Characterization of the prepared materials was carried out using X-ray diffraction (XRD), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) and N2-adsorption-desorption analysis. The presence of Ti and O elements in M-TiO2 and of Ti, V and O elements in M-V doped TiO2 could be detected by SEM-EDS, while the patterns of X-ray diffraction of all the prepared samples had a well-crystalline surface of anatase type. All mesoporous vanadium-doped TiO2 (M-V-doped TiO2) materials performed in a highly transparent mode in the visible region at 554 nm (Eg = 2.24 eV) and 588 nm (Eg = 2.12 eV) for 3.3 and 4.9 wt% V doped TiO2, respectively. The Rietveld refinement method was applied to extract the structural parameters of the M-TiO2 and M-V-doped TiO2 using the Fullprof program in the WinPlotr package. The prepared materials were refined in the crystal system and space group of anatase (tetragonal, I41/amd (141)). The vanadium ion was successfully doped into TiO2. The isotherm type of M-TiO2 and 2.3 wt% V doped TiO2 were of type IV, with a profile of type H2 hysteresis loops, while the 3.3 and 4.9 wt% vanadium-doped TiO2 reflected isotherm type III. The Brunauer-Emmett-Teller (BET) results showed a significant reduction in surface area due to increased concentrations of vanadium. The highest values of BET-specific surface area, pore volume and average pore size of M-TiO2 were 46 m2/g, 18.45 nm and 0.2572 cm3/g respectively.
On Retention of Eventual Stability of Perturbed Impulsive Differential Systems Anju Sood; Sanjay Kumar Srivastava
Journal of Mathematical and Fundamental Sciences Vol. 48 No. 1 (2016)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.math.fund.sci.2016.48.1.1

Abstract

In this paper, a system of non nonlinear differential equations withimpulse effect at fixed time moments is considered and criteria for retention ofuniform eventual stability of its perturbed impulsive differential systems undervanishing perturbations are established. Sufficient conditions are obtained byusing piecewise continuous Lyapunov functions. An example is also worked outto illustrate the results.AMS Subject Classification: 34CXX, 34DXX, 34A37, 34K45.
Cover Vol. 48 No. 1, 2016 Journal of Mathematical and Fundamental Sciences
Journal of Mathematical and Fundamental Sciences Vol. 48 No. 1 (2016)
Publisher : Institute for Research and Community Services (LPPM) ITB

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