Journal of Mathematical and Fundamental Sciences
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The Non Linear Finite Element Model for Characterization of Brick Masonry Infill Wall under Cyclic Lateral Forces
Get PDFBrick masonries as the infill walls between columns, for some degree of horizontal loading, are capable of resisting the horizontal load as shear walls. The different behavior of the structure due to the existence of the brick masonries in this case will change the stiffness as well as the strength of the structure. Ignoring this contribution of the brick masonries develops a misleading concept and design for the structure. In this study, a mathematical model representing the relationship between uniaxial stress vs. strain and the failure envelope of the infill brick wall masonry is developed. The implementation of the model is expected to be capable for analyzing the behavior of the structures subjected to external load in particular under cyclic loading. The model assumes that the contribution of the infill walls are taken into account for the analysis and the brick material used is considered as a compression dominated material. Analysis was carried out using non-linear discrete finite element method. Eight nodal isoparametric elements are developed representing concrete and brick masonry elements. Steel reinforcement and linkage elements are modeled as three nodal plane truss element. The variables studied in the analysis are degree of energy dissipation and stiffness degradation. The result showed that the model gives satisfactory results. However, some improvement needs to be considered in the linkage element model
Pengaruh Dua Macam Perlakuan Mikroorganisme terhadap Kemudahan Degradasi Poliuretan Hasil Sintesis dari Monomer Polietilen Glikol Berat Molekul 400 dengan Metilen-4,4â- difenildiisosianat
Get PDFDegradation of polyurethane sheets using two types of microorganism treatment has been carried out. In this research, the polyurethane sheets were prepared by polyethylene glycol with a molecular weight of 400 and methylene-4,4'-diphenyldiisocyanate at room temperature, followed by heat-pressed at temperature of 180oC. Characterization of polyurethane sheets was based on functional groups using Fourier Transform Infra Red spectrophotometry and thermal properties using Differential Thermal Analysis, and also for physical properties using X-Ray Diffraction. Degradation treatment was carried out by exposing polyurethane to activated sludge and compared to Pseudomonas aeruginosa in a Luria Bertani liquid media at 37oC. The variation of incubation time was 5, 10, 15, 20, 25, and 30 days, respectively with changes of media every 5 days. After degradation, weight loss of polyurethane sheets was determined. The result showed that polyurethane was biodegradable, although at different degradation rate. Weight loss of polyurethanes by activated sludge was higher than by Pseudomonas aeruginosa. Thus, activated sludge was more effective than Pseudomonas aeruginosa in degradating polyurethane. Identification with X-Ray Diffraction showed that degradation decreased the degree of crystallinity of the polyurethane material. Fourier Transform Infra Red spectra after degradation showed that the specific peak for the urethane group disappeared. Variation of the incubation time showed that the polyurethane product had the highest weight loss during the first five days
Effect of pretreatment to the formation of cake layer and membrane structure in the application of ultra filtration cross-flow Membrane for the treatment of oil-water emulsion waste
Get PDFA study on the effect of pretreatment on the use of cellulose acetate (CA) membrane using cross-flow system to treat oil-water emulsion waste came from metal cutting process of an automotive industry has been done. The objectives of this research are to see the impact of pretreatment process to flux and cake forming, indicated by cake forming constant (k'), and to study membrane structure. The ultra filtration process performance was determined by obtaining the values of permeate flux and rejection. The material of membrane used in this process was cellulose acetate membrane with 12 % of cellulose acetate composition for first stage operation and 15 % for second stage operation. The duration of the process was 90 minutes operation time, by applying operation pressure at 3, 5 Bar. There were two types of feeding mode applied, the first was feeding without pretreatment and the second was feeding with pretreatment. After some operation periods, the permeate flux decreases due to fouling. On the first stage of membrane operation, for waste without pretreatment, we obtained the value of k'= 0,0004 m2/L and for waste with pretreatment k'= 0,0001 m2/L. On the second stage membrane operation, for waste without pretreatment the value of k'= 0,0009 m2/L and for waste with pretreatment k'= 0,0002 m2/L. The results mean that pretreatment reduce significantly formation of the cake. It was also obtained that the structure of the membrane is asymmetric. It was shown that deposition of contaminant also occurs within the spinger of the membrane (inner structure of the membrane). Deformation of the membrane spinger was also observed. It is concluded that pretreatment applied to feeding solution increase the running time of the membrane. The benefit of membrane operation used feed with pretreatment, beside increases permeate fluks also decreases the cake forming constant which will longer operation time of membrane
Penggunaan Matrix Analytic Technique pada Perhitungan Parameter Kinerja Proses Handoff
Get PDFThis paper discusses performance evaluation of mobile cellular telecommunication system that is related to the handoff process. We focus our discussion to the system with fixed channel assignment and homogeneous traffic. Performance parameters we discuss in this paper are the blocking probability and the dropping probability of handoff signals, and the blocking probability of new originating call signals.The operator of the system usually gives a service priority to handoff signals compare to new originating call signals. In this paper, the priority is given through channels reservation. A number of channels are reserved so that they can be used only for serving handoff signals. The remaining channels are used for serving new originating call signals and if there is an idle channel, it also can be used for serving handoff signals. With this priority, the arrival process and the service process of both types of signals can be modelled as a queueing network that consists of two queueing systems: one system for handoff signals and one system for both signals.The performance of the queueing network is analyzed by deriving the a two-dimensional Markov process. The system of balance equations of the process, which is needed for obtaining the stationary probability distribution of the process, is a large system. We solve this system by applying Matrix Analytic Technique to the two sub-systems simultaneously. The performance parameter values, which are expressed by the stationary probability distribution, are obtained from the solution
Studi Komparatif Sistem Kendali Bising Aktif Umpan Maju Menggunakan Filter Adaptif Berbasis LMS
Get PDFIn this paper, we discuss simulation and experimental study of the application of Least Mean Square (LMS) based adaptive filter algorithm in active noise control. A number of adaptive filter algorithm based on LMS are investigated, namely Preconditioned Least Mean Square (PLMS), Filtered-reference LMS (FxLMS) and two variants of Filtered-error LMS (FeLMS) algorithms. Active noise control simulation for attenuating recorded blower noise is performed. In case of active noise control experiment, a disturbance is generated by adding three sinus waves with different amplitudes and phases using digital signal processor TMS320C6701, and passing them through primary path. Comparison of the four algorithms is carried out by measuring the performance (in terms of resulting attenuation level) and speed of convergence. Simulation and experiment results demonstrate that PLMS provides the best performance and speed of convergence
Total Edge Irregularity Strength of the Disjoint Union of Helm Graphs
No full textThe total edge irregular k-labeling of a graph G=(V,E) is the labeling of vertices and edges of G in such a way that for any different edges their weights are distinct. The total edge irregularity strength, tes (G), is defined as the minimum k for which G has a total edge irregular k-labeling. In this paper, we consider the total edge irregularity strength of the disjoint union of m special types of helm graphs
Effect of Stimulants on Biogenic Methane Formation and Dynamics of Bacterial Population
No full textCoal bed methane (CBM) is a renewable energy source produced through thermogenic and biogenic activity during the coal formation process. The aim of this research was to stimulate biogenic methane formation using simple carbon as stimulant. The microcosm set-up was done using subbituminous coal at 37°C in an anaerobic chamber. Stimulation with Na-acetate, methanol, formic acid, and no additions, respectively, was carried out for 54 days; observation took place on day 2, 15, 24, 45, and54. The results of all treatments showed differences in the initial pH of the basal medium: 7.76 (Na-acetate), 6.69 (methanol), 4.06 (formic acid), and 8.95 (no stimultant), respectively. Addition of Na-acetate resulted in the highest methane formation rate (5.034 mmol/g coal on day 24 of incubation), followed by methanol (4.377 mmol/g on day 24 of incubation), formic acid (2.520 mmol/g on day 22 of incubation), and no addition (1.2 mmol/g on day 15 of incubation). Using denatured gradient gel electrophoresis (DGGE) it was observed that the microbial population dynamics of the microcosm depended on the stimulant. A decrease of bands indicated that the addition of Na-acetate and methanol had caused a decrease of bacterial diversity during the stimulation process compared to the control treatment (without stimulant)
Studi Penurunan Kandungan Besi Organik dalam Air Tanah dengan Oksidasi H2O2-UV
Get PDFFe(II) terlarut dapat bergabung dengan zat organik dan membentuk senyawa kompleks yang sulit untuk dihilangkan dengan aerasi biasa. Salah satu teknologi alternatif untuk menghilangkan besi tersebut adalah dengan Advanced Oxidation Processes (AOPs) yang dapat menghasilkan radikal hidroksil (OH"¢). OH radikal yang terbentuk mempunyai potensial oksidasi yang tinggi sehingga diharapkan mampu mengoksidasi senyawa besi kompleks zat organik. Penelitian ini bertujuan untuk mengetahui efisiensi penurunan besi menggunakan H2O2-UV, kinetika reaksi yang terjadi, dan melihat pengaruh masing-masing faktor serta interaksi setiap faktor terhadap reaksi oksidasi besi melalui uji statistik. Penelitian ini dilakukan secara batch dengan variasi konsentrasi besi total awal: 3, 5, dan 10 mg/l; Fe:H2O2 = 1:5, 1:8, dan 1:10 (mol/mol); dengan perlakuan menggunakan UV 3x10 watt dan tanpa UV. Hasil penelitian menunjukkan bahwa kombinasi H2O2-UV 3x10 watt memberikan efisiensi penurunan besi yang paling baik pada dosis Fe:H2O2 = 1:5, yaitu 99% dan H2O2 menghasilkan efisiensi paling baik pada dosis Fe:H2O2 = 1: 8, yaitu 84%. Semakin besar konsentrasi besi total awal semakin kecil persen penurunan besi. Tetapi tidak selamanya penambahan dosis H2O2 akan meningkatkan efisiensi. Sedangkan sinar UV memberikan pengaruh yang lebih besar terhadap oksidasi besi apabila dikombinasikan dengan H2O2. Reaksi oksidasi besi ini menghasilkan orde pertama-semu untuk penurunan besi kompleks zat organik dan konstanta laju reaksi semakin besar apabila oksidasi menggunakan H2O2-UV 3 x10 watt. Proses oksidasi dengan H2O2-UV 3x10 watt ini akan menghasilkan persen penurunan Fe-R sebesar 67% setelah diujikan pada air sumur di daerah Bandung
Seismogram Analysis of the Earthquakes in Sumatra on WRAB Observation Station: S Wave Velocity Structure on Subduction Zone of Sumatra-Java.
Get PDFThe S wave velocity structure at subduction zone under Sumatra-Java was investigated through seismogram analysis in time domain and three Cartesian's components simultaneously. The main data set was the comparison between the measured seismogram and the synthetic one, not the travel time data. The synthetic seismogram was calculated with the GEMINI method. The seismogram comparison shows that the global earth mantle of PREMAN gives deviating synthetic seismogram and has later arrival times than the measured one. The gradient âh in the upper mantle is altered to positive from its negative slope as in the PREMAN model, and positive corrections are added to the zero order of polynomial's coefficients in all earth mantle layers. The excellent fitting, as well as travel time or waveform, were obtained on the surface waves of Love and Rayleigh, the S and SS mantle and repetitive depth waves. The additional positive corrections were also confirmed by a well fitting on the repetitive depth waves. This result expresses that part of the earth mantle that due to tectonic processes has positive anomaly on S wave velocity and vertical anisotropy in all of the earth mantle layers
Effect of Growth Temperature and Mn Incorporation on GaN:Mn Thin Films Grown by Plasma-Assisted MOCVD
Get PDFIn this paper, the growth of GaN:Mn thin films by plasma-assisted metalorganic chemical vapor deposition (PAMOCVD) method is reported. The method used in this study, utilizes a microwave cavity as a cracking cell to produce nitrogen radicals, which in turn reduce the growth temperature. Trimethylgallium (TMGa), nitrogen (N2) and cyclopentadienyl manganese tricarbonyl (CpMnT) were used as a source of Ga, N and Mn, respectively, while hydrogen gas was used as a carrier gas for both TMGa and CpMnT. The effect of growth temperature and Mn incorporation on structural properties and surface morphology of GaN:Mn films are presented. The growth of GaN:Mn thin films were conducted at varied growth temperature in range of 625 oC to 700 oC and the Mn/Ga molar fraction in the range of 0.2 to 0.5. Energy dispersive of X-ray (EDX) and X-ray diffraction (XRD) methods were used to analyze atomic composition and crystal structure of the grown films, respectively. The surface morphology was then characterized using both atomic force microscopy (AFM) and scanning electron microscopy (SEM) images. A systematic XRD analysis reveal that maximum Mn incorporation that still produces single phase GaN:Mn (0002) is 6.4 % and 3.2 % for the film grown at 650 oC and 700 oC, respectively. The lattice constant and full width at half maximum (FWHM) of the single phase films depend on the Mn concentration. The decrease in lattice constant accompanied by the increase in FWHM is due to incorporation of substitutional Mn on the Ga sub-lattice. The maximum values of doped Mn atoms incorporated in the wurtzite structure of GaN:Mn as substitutional atoms on Ga sub-lattice are 2.0 % and 2.5 % at 650 oC and 700 oC, respectively. AFM and SEM images show that the film grown at lower growth temperature and Mn concentration has a better surface than that of film grown at higher growth temperature and Mn concentration