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Articles 991 - 1020 of 1187

Full-Text Articles in Mechanical Engineering

Utilization Of Bagasse Cellulose For Ethanol Production Through Simultaneous Saccharification And Fermentation By Xylanase, M. Samsuri, Misri Gozan, R. Mardias, M. Baiquni, Heri Hermansyah, Anondho Wijanarko, Bambang Prasetya, M. Nasikin Apr 2007

Utilization Of Bagasse Cellulose For Ethanol Production Through Simultaneous Saccharification And Fermentation By Xylanase, M. Samsuri, Misri Gozan, R. Mardias, M. Baiquni, Heri Hermansyah, Anondho Wijanarko, Bambang Prasetya, M. Nasikin

Makara Journal of Technology

Utilization of Bagasse Cellulose for Ethanol Production through Simultaneous Saccharification and Fermentation by Xylanase. Bagasse is a solid residue from sugar cane process, which is not many use it for some product which have more added value. Bagasse, which is a lignosellulosic material, be able to be use for alternative energy resources like bioethanol or biogas. With renewable energy resources a crisis of energy in Republic of Indonesia could be solved, especially in oil and gas. This research has done the conversion of bagasse to bioethanol with xylanase enzyme. The result show that bagasse contains of 52,7% cellulose, 20% hemicelluloses, …

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Construction Of Short-Length High-Rates Ldpc Codes Using Difference Families, Deny Hamdani, Ery Safrianti Apr 2007

Construction Of Short-Length High-Rates Ldpc Codes Using Difference Families, Deny Hamdani, Ery Safrianti

Makara Journal of Technology

Low-density parity-check (LDPC) code is linear-block error-correcting code defined by sparse parity-check matrix. It is decoded using the massage-passing algorithm, and in many cases, capable of outperforming turbo code. This paper presents a class of low-density parity-check (LDPC) codes showing good performance with low encoding complexity. The code is constructed using difference families from combinatorial design. The resulting code, which is designed to have short code length and high code rate, can be encoded with low complexity due to its quasi-cyclic structure, and performs well when it is iteratively decoded with the sum-product algorithm. These properties of LDPC code are …

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Kinetic Model For Triglyceride Hydrolysis Using Lipase:Review, Heri Hermansyah, A. Wijanarko, Dianursanti Dianursanti, Misri Gozan, Praswasti P. D.K Wulan, Rita Arbianti, Roekmijati W. Soemantojo, Tania Surya Utami, Yuliusman Yuliusman, Momoji Kubo, Naomi Shibasaki Kitakawa, Toshiy Yonemoto Apr 2007

Kinetic Model For Triglyceride Hydrolysis Using Lipase:Review, Heri Hermansyah, A. Wijanarko, Dianursanti Dianursanti, Misri Gozan, Praswasti P. D.K Wulan, Rita Arbianti, Roekmijati W. Soemantojo, Tania Surya Utami, Yuliusman Yuliusman, Momoji Kubo, Naomi Shibasaki Kitakawa, Toshiy Yonemoto

Makara Journal of Technology

Triglyceride hydrolysis using lipase has been proposed as a novel method to produce raw materials in food and cosmetic industries such as diacylglycerol, monoacylglycerol, glycerol and fatty acid. In order to design a reactor for utilizing this reaction on industrial scale, constructing a kinetic model is important. Since the substrates are oil and water, the hydrolysis takes place at oil-water interface. Furthermore, the triglyceride has three ester bonds, so that the hydrolysis stepwise proceeds. Thus, the reaction mechanism is very complicated. The difference between the interfacial and bulk concentrations of the enzyme, substrates and products, and the interfacial enzymatic reaction …

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Sulfonation Of Cptfe Film Grafted Styrene For Proton Exchange Membrane Fuel Cell, Yohan Yohan Apr 2007

Sulfonation Of Cptfe Film Grafted Styrene For Proton Exchange Membrane Fuel Cell, Yohan Yohan

Makara Journal of Technology

Sulfonation of cPTFE Film grafted Styrene for Proton Exchange Membrane Fuel Cell. Sulfonation of γ-ray iradiated and styrene-grafted crosslinked polytetrafluoroethylene film (cPTFE-g-S film) have been done. The aim of the research is to make hydropyl membrane as proton exchange membrane fuel cell. Sulfonation was prepared with chlorosulfonic acid in chloroethane under various conditions. The impact of the percent of grafting, the concentration of chlorosulfonic acid, the reaction time,and the reaction temperature on the properties of sulfonated film is examinated. The results show that sulfonation of surface-grafted films is incomplete at room temperature. The increasing of concentration of chlorosulfonic acid and …

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Thermoeconomics Of Seasonal Latent Heat Storage System, Yaşar Demirel, H. Hüseyin Öztürk Mar 2007

Thermoeconomics Of Seasonal Latent Heat Storage System, Yaşar Demirel, H. Hüseyin Öztürk

Papers in Thermal Mechanics

A simple thermoeconomic analysis is performed for a seasonal latent heat storage system for heating a greenhouse. The system consists of three units that are a set of 18 packed-bed solar air heaters, a latent heat storage tank with 6,000 kg of technical grade paraffin wax as phase-changing material, and a greenhouse of 180m2. The cost rate balance for the output of a unit is used to estimate the specific cost of exergy for a yearly operation. Based on the cost rate of exergy, fixed capital investment, operating cost, and economic data, approximate cash-flow diagrams have been prepared. The systems …

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Mechanical Characterization Of Spherical Hydrogels: Contact Diameter Measurement, Joshua Bunch Jan 2007

Mechanical Characterization Of Spherical Hydrogels: Contact Diameter Measurement, Joshua Bunch

Opportunities for Undergraduate Research Experience Program (OURE)

In an effort to develop new ophthalmic treatments revolving around the ocular lens, the mechanical characteristics of natural ocular lenses and synthetic models must be determined and compared. One mechanical characteristic that is necessary when making comparisons is the variation of contact circle diameter or contact area with varying strains. A method was used in this experiment to measure the varying contact circle diameter of spherical hydrogels at strains up to 15%. This method could be used to estimate the varying contact diameter of other similar materials such as natural ocular lenses if the precision of the method is improved. …

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Thermal Effectiveness Characteristics Of Low Approach Indirect Evaporative Cooling Systems In Buildings, Ben Costelloe, Donal Finn Jan 2007

Thermal Effectiveness Characteristics Of Low Approach Indirect Evaporative Cooling Systems In Buildings, Ben Costelloe, Donal Finn

Articles

Meteorological enthalpy analysis of temperate and maritime climates above latitude 45°N suggests that the water-side evaporative cooling technique has considerable unrealised potential with contemporary “high temperature” building cooling systems—such as chilled ceilings and displacement ventilation. As low approach conditions are the key to exploiting the cooling potential of the ambient air, thermal performance at such conditions needs to be investigated. To address the research issues, an industrial scale test rig, based on a low approach open cooling tower and plate heat exchanger and designed to maximise evaporative cooling potential, has been constructed. The thermal effectiveness of such systems (as a …

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Accelerated Testing Method For Pem Fuel Cell Based Uninterrupted Power Supply Systems, Xinyu Huang, Xiaofeng Wang Jan 2007

Accelerated Testing Method For Pem Fuel Cell Based Uninterrupted Power Supply Systems, Xinyu Huang, Xiaofeng Wang

Faculty Publications

Proton exchange membrane fuel cell based power systems are on the verge of commercialization for a number of niche applications where batteries are traditionally used. Uninterrupted power supply (UPS) for wireless communication towers and broadband network relay utilities is one of the targeted application of fuel cell power systems with capacity ranging from one to serveral kilowatts. It is believed that fuel cell based UPS systems can offer considerable advantage when extended backup time is desirable. In order to replace the well-known battery based UPS systems, the reliability and perofrmance of fuel cell based UPS system need to be thoroughly …

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Biogasoline Production From Palm Oil Via Catalytic Hydrocracking Over Gamma-Alumina Catalyst, Anondho Wijanarko, Dadi Ahmad Mawardi, Mohammad Nasikin Nov 2006

Biogasoline Production From Palm Oil Via Catalytic Hydrocracking Over Gamma-Alumina Catalyst, Anondho Wijanarko, Dadi Ahmad Mawardi, Mohammad Nasikin

Makara Journal of Technology

Biogasoline Production from Palm Oil Via Catalytic Hydrocracking over Gamma-Alumina Catalyst. Bio gasoline conversion from palm oil is an alternative energy resources method which can be substituted fossil fuel base energy utilization. Previous research resulted that palm oil can be converted into hydrocarbon by catalytic cracking reaction with γ-alumina catalyst. In this research, catalytic cracking reaction of palm oil by γ-alumina catalyst is done in a stirrer batch reactor with the oil/catalyst weight ratio variation of 100:1, 75:1, and 50:1; at suhue variation of 260 to 340oC and reaction time variation of 1 to 2 hour. Post cracking reaction, bio …

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Segmental Sinusoidal Model For Speech Signal Coding, Florentinus Budi Setiawan, Soegijardjo Soegijoko, Sugihartono Sugihartono, Suhartono Tjondronegoro Nov 2006

Segmental Sinusoidal Model For Speech Signal Coding, Florentinus Budi Setiawan, Soegijardjo Soegijoko, Sugihartono Sugihartono, Suhartono Tjondronegoro

Makara Journal of Technology

Segmental Sinusoidal Model for Speech Signal Coding. Periodic signal can be decomposed by sinusoidal component with Fourier series. With this characteristic, it can be modeled referring by sinusoidal form. By the sinusoidal model, signal can be quantized in order to encode the speech signal at the lower rate. The recent sinusoidal method is implemented in speech coding. By using this method, a block of the speech signal with 20 ms to 30 ms width is coded based on Fourier series coefficients. The new method proposed is quantization and reconstruction of speech signal by the segmental sinusoidal model. A segment is …

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A Study On Parallel Computation Tools On Networked Pcs, Heru Suhartanto Nov 2006

A Study On Parallel Computation Tools On Networked Pcs, Heru Suhartanto

Makara Journal of Technology

A Study on Parallel Computation Tools on Networked PCs. Many models for natural phenomena, engineering applications and industries need powerfull computing resources to solve their problems. High Performance Computing resources were introduced by many researchers. This comes in the form of Supercomputers and with operating systems and tools for development such as parallel compiler and its library. However, these resources are expensive for the investation and maintenance, hence people need some alternatives. Many people then introduced parallel distributed computing by using available computing resource such as PCs. Each of these PCs is treated as a processors, hence the cluster of …

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Crude Oil Sludge Degradation In Microcosmic Scale: Simple Simulation As Preliminary Study On Land Treatment Bioremediation., Astri Nugroho Nov 2006

Crude Oil Sludge Degradation In Microcosmic Scale: Simple Simulation As Preliminary Study On Land Treatment Bioremediation., Astri Nugroho

Makara Journal of Technology

Crude Oil Sludge Degradation in Microcosmic Scale: Simple Simulation as Preliminary Study on Land Treatment Bioremediation. A study in microcosmic condition has been carried out to evaluate the bacterial hydrocarbonoclastic capability in increasing the oil sludge degradation being mixed with NPK fertilizer as nitrogen resources. Aerobic test was carried out by putting erlenmeyers in a shaker incubator, 120 rpm shaking speed, at 50°C temperature. While 150 days in microcosmic one observation showed that the consortium has the potential to grow up to 50% (v/v) sludge oil load. Maximum growth and maximum growth rate of the consortium occurred in the III …

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Determination Of Operation Condition And Product Dimension Accuracy Optimization Of Filament Deposition Modelling On Layer Manufacturing Application, Slamet A. Widyanto, Alva Edy Tontowi, Jamasri Jamasri, Heru Santoso Budi Rochardjo Nov 2006

Determination Of Operation Condition And Product Dimension Accuracy Optimization Of Filament Deposition Modelling On Layer Manufacturing Application, Slamet A. Widyanto, Alva Edy Tontowi, Jamasri Jamasri, Heru Santoso Budi Rochardjo

Makara Journal of Technology

Layer manufacturing process has proven as a process that can produce a high complexity mechanical part. Now, Improvement of LM methods continuously conduct that is aimed to increase precessions and efficiency of these processes. Pressure filament deposition modelling is a form of layer manufacturing process that is designed to produce a plastic part with controlling its semisolid phase. In this research, the equipment of filament depositor is designed and tested to make the product filament deposition. With operation condition observation, the optimal temperature and pressure of deposition process was determined. These experiments used PVC as crystalline material and polypropylene as …

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Magnetic Field Effects On Caco3 Precipitation Process In Hard Water, Nelson Saksono, Setijo Bismo, Elsa Krisanti, Azwar Manaf, Roekmijati Widaningrum Nov 2006

Magnetic Field Effects On Caco3 Precipitation Process In Hard Water, Nelson Saksono, Setijo Bismo, Elsa Krisanti, Azwar Manaf, Roekmijati Widaningrum

Makara Journal of Technology

Magnetic Field Effects on CaCO3 Precipitation Process in Hard Water. Magnetic treatment is applied as physical water treatment for scale prevention especially CaCO3, from hard water in piping equipment by reducing its hardness. Na2CO3 and CaCl2 solution sample was used in to investigate the magnetic fields influence on the formation of particle of CaCO3. By changing the strength of magnetic fields, exposure time and concentration of samples solution, this study presents quantitative results of total scale deposit, total precipitated CaCO3 and morphology of the deposit. This research was run by comparing magnetically and non-magnetically treated samples. The results showed an …

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Stress Corrosion Cracking Behavior Of Stainless Steel 304 In The Sulfuric Acid Environment Due To Prestrain, Mohammad Badaruddin, Ahmad Suudi, Arinal Hamni Nov 2006

Stress Corrosion Cracking Behavior Of Stainless Steel 304 In The Sulfuric Acid Environment Due To Prestrain, Mohammad Badaruddin, Ahmad Suudi, Arinal Hamni

Makara Journal of Technology

Stress Corrosion Cracking Behavior of Stainless Steel 304 in the Sulfuric Acid Environment Due to Prestrain. The aim of research is to investigate the effect of prestrain on the stress corossion cracking behavior of AISI 304 stainless steel in the sulfuric acid of 10% concentration under the static cantilever loading according to ASTM E-1681 standart. The specimen of 304 Stainless steel was strain up over the yield strength until reaching the uniform strain of 5% and 10% using servopulser UTM 9506 under the displacement control of 0,3 mm/sec. The results of test show that the prestrain of 5% specimen is …

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A Study Correlating Entropy Generation To Parameters Characterizing Thermal Comfort In A Conditioned Room, Sai Shrinivas Sreedharan Oct 2006

A Study Correlating Entropy Generation To Parameters Characterizing Thermal Comfort In A Conditioned Room, Sai Shrinivas Sreedharan

Mechanical & Aerospace Engineering Theses & Dissertations

Although significant advances have been made to analyze and study a room as an open thermodynamic system experiencing indoor airflow and heat exchanges with surroundings, studies incorporating entropy generation in the analysis have been sparse. This study focuses on correlating indoor thermal comfort with entropy generation, which hopefully will result in efficient utilization of energy supplied to the system. The problem that this thesis attempts to solve involves calculation of entropy production in conditioned space and its correlation to parameters that characterize thermal comfort. Thermal comfort in a conditioned space is governed by many thermal, mechanical and psychrometric parameters. The …

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Socio-Economic Impacts Of Computer Viruses In Tanzania, M Victor Jun 2006

Socio-Economic Impacts Of Computer Viruses In Tanzania, M Victor

Tanzania Journal of Engineering and Technology (TJET)

This paper reports on a research project conducted with an objective of identifying and assessing various approaches used by different computer users (Management, System Administrators and end users) in Tanzania to combat computer viruses (CVs), and to assess users' awareness level on CVs. Specifically, the study aimed at assessing the awareness level on CVs to the Tanzanian business community; analyze the socio -economic impact caused by CVs in Tanzania and; assess existing methods, capacity and limitations on controlling CVs in Tanzania. Data was collected using both questionnaires and interview from financial institutions such as NBC and BOT, and telecommunications sector …

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Non-Isothermal Reaction-Diffusion Systems With Thermodynamically Coupled Heat And Mass Transfer, Yaşar Demirel May 2006

Non-Isothermal Reaction-Diffusion Systems With Thermodynamically Coupled Heat And Mass Transfer, Yaşar Demirel

Papers in Analytical Chemistry

Non-isothermal reaction-diffusion (RD) systems control the behavior of many transport and rate processes in physical, chemical, and biological systems. A considerable work has been published on mathematically coupled nonlinear differential equations of RD systems by neglecting the possible thermodynamic couplings among heat and mass fluxes, and reaction velocities. Here, the thermodynamic coupling refers that a flux occurs without its primary thermodynamic driving force, which may be gradient of temperature, or chemical potential, or reaction affinity. This study presents the modeling equations of non-isothermal RD systems with coupled heat and mass fluxes excluding the coupling of chemical reactions using the linear …

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2nd Annual Undergraduate Research Conference Abstract Book, University Of Missouri--Rolla Apr 2006

2nd Annual Undergraduate Research Conference Abstract Book, University Of Missouri--Rolla

Undergraduate Research Conference at Missouri S&T

No abstract provided.

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Effect Of Firing Temperature And Holding Time On Characterization Of Al/Sic Metal Matrix Composites Produced By Pressureless Infiltration., Anne Zulfia, Myrna Ariati Apr 2006

Effect Of Firing Temperature And Holding Time On Characterization Of Al/Sic Metal Matrix Composites Produced By Pressureless Infiltration., Anne Zulfia, Myrna Ariati

Makara Journal of Technology

Effect of Firing Temperature and Holding Time on Characterization of Al/SiC Metal Matrix Composites Produced by Pressureless Infiltration. The production of Al-SiC metal matrix composite can be carried out by pressureless metal infiltration processs (PRIMEX). The experiment was conducted using aluminium AC2B ingot as a matrix and 50%Vf SiC powder as a reinforcement which is mixed with 10% Mg powder for wetting agent. The variables of this experiment are holding time and firing temperature to investigate the effect of these conditions on mechanical properties of Al-SiC metal matrix composites. Holding time was conducted for 2,5,8,10,12 hours and firing temperatures was …

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Modification Of Bonding Strength Test Of Wc Hvof Thermal Spray Coating On Rocket Nozzle, Bondan T. Sofyan, Haposan J. Pardede, Marizki Stefano, Edi Sofyan Apr 2006

Modification Of Bonding Strength Test Of Wc Hvof Thermal Spray Coating On Rocket Nozzle, Bondan T. Sofyan, Haposan J. Pardede, Marizki Stefano, Edi Sofyan

Makara Journal of Technology

Modification of Bonding Strength Test of WC HVOF Thermal Spray Coating on Rocket Nozzle. One way to reduce structural weight of RX-100 rocket is by modifying the nozzle material and processing. Nozzle is the main target in weight reduction due to the fact that it contributes 30 % to the total weight of the structur. An alternative for this is by substitution of massive graphite, which is currently used as thermal protector in the nozzle, with thin layer of HVOF (High Velocity Oxy-Fuel) thermal spray layer. This paper presents the characterization of nozzle base material as well as the modification …

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Development Of Fiber-Optic Humidity Sensor Probe With Gelatin Cladding, Akhiruddin Maddu, Kun Modjahidin, Sar Sardy, Hamdani Zain Apr 2006

Development Of Fiber-Optic Humidity Sensor Probe With Gelatin Cladding, Akhiruddin Maddu, Kun Modjahidin, Sar Sardy, Hamdani Zain

Makara Journal of Technology

Development of Fiber-Optic Humidity Sensor Probe with Gelatin Cladding. Humidity sensor based on optical fiber with gelatin cladding has been developed. In this humidity sensor probe, the origin cladding of optical fiber is replaced by gelatin coating as humidity sensitive cladding. Testing of the optical fiber sensor probe was conducted by measuring of light intensity transmitted on the optical fiber probe for each variation of different humidity treatments. Response of the optical fiber sensor probe measured from 42%RH to 99%RH, the results show an optical transmission curve varied with relative humidity (RH). Optical transmission in the optical fiber probe increase …

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Retrofit Of Distillation Columns Using Thermodynamic Analysis, Yaşar Demirel Apr 2006

Retrofit Of Distillation Columns Using Thermodynamic Analysis, Yaşar Demirel

Papers in Physical Properties

Thermodynamic analysis provides the column grand composite curves and exergy loss profiles, which are becoming readily available for a converged distillation column simulation. For example, the Aspen Plus simulator performs the thermodynamic analysis through its Column–Targeting tool for rigorous column calculations. This study uses the column grand composite curves and the exergy loss profiles obtained from Aspen Plus to assess the performance of the existing distillation columns, and reduce the costs of operation by appropriate retrofits in a methanol plant. Effectiveness of the retrofits is also assessed by means of thermodynamics and economics. The methanol plant utilizes two distillation columns …

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On The Performance Of Imt-2000 Communication Link Based On Stratospheric Platforms, Iskandar Iskandar, Shigeru Shimamoto Apr 2006

On The Performance Of Imt-2000 Communication Link Based On Stratospheric Platforms, Iskandar Iskandar, Shigeru Shimamoto

Makara Journal of Technology

A new means for providing wireless communication has been currently proposed. It is based on aerial vehicle known as High Altitude Platform or Stratospheric Platforms (SPF). The SPF will be operated at an altitude of 17-22 km above the ground. Therefore, the channel condition may be different compared with those of the conventional terrestrial or satellite wireless channel. In this paper, the channel propagation characteristic of such a system is firstly investigated by means of ray tracing algorithm. We emphasize our investigation in a typical urban environment, in which the mobile users mostly exist. We developed building block model for …

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Analysis Of Technical Energy Losses By Using Simulation, Betrianis Betrianis, Randite Herawan Apr 2006

Analysis Of Technical Energy Losses By Using Simulation, Betrianis Betrianis, Randite Herawan

Makara Journal of Technology

Model is a representation of a system. Through model, it can be easier to forecast and control the changing of each element system. Electricity distribution is also a system. Losses are general problem that exist in a distribution network system. But with the right methods, specifically technical energy losses can be reduced in order to increase the efficiency. By making model of the distribution network, the value of technical energy losses in the whole network as well as in every line can be observed. Simulation can also be used to see all losses reduction alternatives. By comparing results from each …

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Modeling Of Coupled-Tank System Using Fuzzy Takagi-Sugeno Model, Aries Subiantoro Apr 2006

Modeling Of Coupled-Tank System Using Fuzzy Takagi-Sugeno Model, Aries Subiantoro

Makara Journal of Technology

Modeling of Coupled-Tank System Using Fuzzy Takagi-Sugeno Model. This paper describes modeling of coupledtank system based on data measurement using fuzzy Takagi-Sugeno model. The fuzzy clustering method of Gustafson- Kessel algorithm is used to classify input-output data into several clusters based on distance similarity of a member of input-output data from center of cluster. The formed clusters are projected orthonormally into each linguistic variables of premise part to determine membership function of fuzzy Takagi-Sugeno model. By estimating data in each cluster, the consequent parameters of fuzzy Takagi-Sugeno model are calculated using weighted least-squares method. The resulted fuzzy Takagi-Sugeno model is …

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Design Of Induction Motor Drive Without Velocity Sensor Using Current Vector Controller With Full And Reduced Observer Moving To Dq Axis, Ridwan Gunawan, Feri Yusivar, Wahidin Wahab, Zuhal A. Kadir Apr 2006

Design Of Induction Motor Drive Without Velocity Sensor Using Current Vector Controller With Full And Reduced Observer Moving To Dq Axis, Ridwan Gunawan, Feri Yusivar, Wahidin Wahab, Zuhal A. Kadir

Makara Journal of Technology

Design of Induction Motor Drive Without Velocity Sensor Using Current Vector Controller with Full and Reduced Observer Moving to DQ Axis. The observer is used in estimation velocity sensor usually in α-β axis, therefore this situation will need an extra transformation when we want to add compensator because the flux model is in direct and quadrature-axis dq. Every used the transformation to make possible emerge an error. So in this simulation is used a method to estimate the velocity of induction motor drive with observer that is moved to dq-axis. The model of actual motor used is in alfa-beta axis, …

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Hybrid Identification System With Arx And Fast Fourier Transform In Application Of A Quarter Of Vehicle Half Active Suspension, Noveri Lysbetti M, Antonius R. Apr 2006

Hybrid Identification System With Arx And Fast Fourier Transform In Application Of A Quarter Of Vehicle Half Active Suspension, Noveri Lysbetti M, Antonius R.

Makara Journal of Technology

Hybrid Identification System with ARX and Fast Fourier Transform in Application of a Quarter of Vehicle Half Active Suspension. In a control system problem, identification system mechanism is a absolute thing, especially in adaptation controlling to disturbance changing. For that case, is needed an identification method which can identify the changing of disturbance in that system. The aim of this research is to give an alternative in system/plant identification which is a combination (hybrid) of ARX and Fast Fourier Transform. So, it is needed an algorithm design for identification process. In this case, the designed algorithm will be implemented in …

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High-Pressure Torsion-Induced Grain Growth In Electrodeposited Nanocrystalline Ni, X. Z. Liao, A. R. Kilmametov, R. Z. Valiev, Hongsheng Gao, Xiaodong Li, A. K. Mukherjee, J. F. Blingert, Y. T. Zhu Jan 2006

High-Pressure Torsion-Induced Grain Growth In Electrodeposited Nanocrystalline Ni, X. Z. Liao, A. R. Kilmametov, R. Z. Valiev, Hongsheng Gao, Xiaodong Li, A. K. Mukherjee, J. F. Blingert, Y. T. Zhu

Faculty Publications

Deformation-induced grain growth has been reported in nanocrystalline (nc) materials under indentation and severe cyclic loading, but not under any other deformation mode. This raises an issue on critical conditions for grain growth in nc materials. This study investigates deformation-induced grain growth in electrodeposited nc Ni during high-pressure torsion (HPT). Our results indicate that high stress and severe plastic deformation are required for inducing grain growth, and the upper limit of grain size is determined by the deformation mode and parameters. Also, texture evolution suggests that grain-boundary-mediated mechanisms played a significant role in accommodating HPT strain.

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Synthesis Of Fuel Cell Membrane: Copolymerization Of Styrene On Etfe Film By Grafted Pre-Irradiation, Yohan Yohan, Rifai M. Nur, Lilik Hendrajaya, E. S. Siradj Nov 2005

Synthesis Of Fuel Cell Membrane: Copolymerization Of Styrene On Etfe Film By Grafted Pre-Irradiation, Yohan Yohan, Rifai M. Nur, Lilik Hendrajaya, E. S. Siradj

Makara Journal of Technology

Synthesis of Fuel Cell Membrane: Copolymerization of Styrene on ETFE Film by Grafted pre-Irradiation. Preirradiation Grafting styrene monomer on ETFE film has been prepared. Research has been performed by γ-ray radiation at various total dose from 2.5 – 12.5 kGy and various dose rate from 1.3 – 1.9 kGy/hour. Irradiated copolymer is then grafted by styrene monomer in various solvent: ethanol, 2-propanol, and toluene, various concentration from 20 – 70% volume, various temperature from 50 – 90oC, and various grafting time from 2 – 12 hours. The results showed that percent of grafting is increase with increase of total dose …

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