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Articles 1 - 28 of 28
Full-Text Articles in Mechanical Engineering
Analysis Of Three Phase Controlled Rectifier With The Same Distance Control As Compared To The Same Angle Control, Sudirman S., Sri Kurniati A.
Analysis Of Three Phase Controlled Rectifier With The Same Distance Control As Compared To The Same Angle Control, Sudirman S., Sri Kurniati A.
Makara Journal of Technology
Analysis of three phase controlled rectifier with the same distance control as compared to the same angle control. This research aim to compare the firing of the same distance and the same angle control at three phase controlled rectifier with seen generated harmonic at input (AC side). Then calculate of rectifier efficiency and power factor comparison from both the control type. The rectifier use passive filter with resistance 11 ohm and is analysed with program simulation using PSPICE version 7.1. Result of research indicate that use of the same distance control generates the 5th and 7th harmonics, while the same …
Limiting Maximum Drag Reduction Asymptote For The Moment Coefficient Of An Enclosed Rotating Disk With Fine Spiral Grooves, Budiarso Budiarso, Keizo Watanabe, Satoshi Ogata
Limiting Maximum Drag Reduction Asymptote For The Moment Coefficient Of An Enclosed Rotating Disk With Fine Spiral Grooves, Budiarso Budiarso, Keizo Watanabe, Satoshi Ogata
Makara Journal of Technology
In this study, the limiting maximum drag reduction asymptote for the moment coefficient of an enclosed rotating disk with fine spiral grooves in turbulent flow region were obtained analytically. Analysis which were based on an assumption for a simple parabolic velocity distribution of turbulent pipe flow to represent relative tangential velocity, was carried out using momentum integral equations of the boundary layer. For a certain K- parameter the moment coefficient results agree well with experimental results for maximum drag reduction in an enclosed rotating disk with fine spiral grooves and drag reduction ratio approximately was 15 %. Additionally, the experimental …
Reverse Link Cdma System Capacity Evaluation For Stratospheric Platform Mobile Communications, Iskandar Iskandar
Reverse Link Cdma System Capacity Evaluation For Stratospheric Platform Mobile Communications, Iskandar Iskandar
Makara Journal of Technology
We propose an analysis of reverse link CDMA multispot beam stratospheric platforms (SPF) in this paper. The SPF is currently proposed as a novel wireless technology for the development of the next generation fixed and mobile communications. The geometry of this technology is different from that of the terrestrial but rather similar to the satellite based cellular system. However, evaluation on the CDMA system capacity of this technology has not been much reported. This paper addresses all possible multiple access interference analyses including the effects of channel fading and shadowing in order to evaluate the system capacity. Single SPF and …
Trajectory Shaping Of Surface-To-Surface Missile With Terminal Impact Angle Constraint, S. Subchan
Trajectory Shaping Of Surface-To-Surface Missile With Terminal Impact Angle Constraint, S. Subchan
Makara Journal of Technology
This paper presents trajectory shaping of a surface-to-surface missile attacking a fixed with terminal impact angle constraint. The missile must hit the target from above, subject to the missile dynamics and path constraints. The problem is reinterpreted using optimal control theory resulting in the formulation of minimum integrated altitude. The formulation entails nonlinear, two-dimensional missile flight dynamics, boundary conditions and path constraints. The generic shape of optimal trajectory is: level flight, climbing, diving; this combination of the three flight phases is called the bunt manoeuvre. The numerical solution of optimal control problem is solved by a direct collocation method. The …
Effect Of Contact Time On Interface Reaction Between Aluminum Silicon (7% And 11%) Alloy And Steel Dies Skd 61, Bambang Suharno, Neni Octapiani Nurhayati, Bustanul Arifin, Sri Harjanto
Effect Of Contact Time On Interface Reaction Between Aluminum Silicon (7% And 11%) Alloy And Steel Dies Skd 61, Bambang Suharno, Neni Octapiani Nurhayati, Bustanul Arifin, Sri Harjanto
Makara Journal of Technology
Effect of Contact Time on Interface Reaction between Aluminum Silicon (7% and 11%) Alloy and Steel Dies SKD 61. Die soldering (die sticking) is a defect of metal casting in which molten metal “welds” to the metallic die mold surface during casting process. Die soldering is the result of an interface reaction between the molten aluminum and the die material. Aluminum alloy with 7 and 11% silicon and SKD 61 die steel are the most common melt and die material used in aluminum die casting. This research is done to study the morphology and the characteristics of the formed AlxFeySiz …
Co2 Absorption From Its Mixture With Ch4 Or N2 Through Hollow Fiber Membrane Contactor Using Water As Solvent, Sutrasno Kartohardjono, Anggara Anggara, Subihi Subihi, Yuliusman Yuliusman
Co2 Absorption From Its Mixture With Ch4 Or N2 Through Hollow Fiber Membrane Contactor Using Water As Solvent, Sutrasno Kartohardjono, Anggara Anggara, Subihi Subihi, Yuliusman Yuliusman
Makara Journal of Technology
CO2 Absorption from Its Mixture with CH4 or N2 through Hollow Fiber Membrane Contactor using Water as Solvent. Hollow fiber membrane contactors have been widely used as gas-liquid contactors recently such as in the CO2 absorption process from gas stream. This research aims to evaluate the effectiveness of hollow fiber membrane contactor to absorb CO2 from its mixture with CH4 or N2 using water through mass transfer and hydrodynamic tests. There are 3 membrane modules used in this research with shell diameter of 1.9 cm, length of 40 cm, outer fiber diameter of 2.7 mm and fiber number in the …
The Use Of Red Cabbage’S Anthocyanine Extract As A Photosensitizer On A Dye-Sensitized Nanocrystalline Tio2 Solar Cell, Akhiruddin Maddu, Mahfuddin Zuhri, Irmansyah Irmansyah
The Use Of Red Cabbage’S Anthocyanine Extract As A Photosensitizer On A Dye-Sensitized Nanocrystalline Tio2 Solar Cell, Akhiruddin Maddu, Mahfuddin Zuhri, Irmansyah Irmansyah
Makara Journal of Technology
The use of Red Cabbage’s anthocyanine extract as a photosensitizer on a Dye-Sensitized Nanocrystalline TiO2 Solar Cell. A solid-state dye-sensitized nanocrystalline TiO2 solar cell utilizing anthocyanin extract form red cabbage as photosensitizer was fabricated. The solar cell was formed in sandwich structure, which two electrodes sandwiching polymer electrolyte containing a redox couple (I-/I3 -). One of the electrodes, namely working electrode, TiO2 layer on TCO (transparent conducting oxide) coated glass substrate was sensitized with anthocyanin dye as electron donor in the system. Another electrode was a carbon sheet as a counter electrode. Gel electrolyte based on PEG (polyethylene glycol) containing …
The Potency Of Fire And Explosion Hazard On Premium Oil Storage Tank At Depot X 2007, Fatma Lestari, Warid Nurdiansyah
The Potency Of Fire And Explosion Hazard On Premium Oil Storage Tank At Depot X 2007, Fatma Lestari, Warid Nurdiansyah
Makara Journal of Technology
The Potency of Fire and Explosion Hazard on Premium Oil Storage Tank at Depot X 2007. Premium oil storage tanks have fire and explosion risk because Premium oil is flammable liquid. Because of that, fire and explosion risk assessment on Premium oil storage tank at Depot X is needed as foundation to fire and explosion risk management, and comply with regulations. Method of this research is Dow’s Fire and Explosion Index. This research indicate that F&EI value for Premium oil storage tank is 118,82. Based on that F&EI value, level of risk at Premium oil storage tank is intermediate risk.
Study On The Characteristics Of Tiller Blade Shapes By Spray-Welding Hardening, Jain-Song Ju
Study On The Characteristics Of Tiller Blade Shapes By Spray-Welding Hardening, Jain-Song Ju
Journal of Marine Science and Technology
This study attempts to validate and analyze the mathematical models of the plowing dynamics and trajectory curve for tiller and cultivation blades of a rotary cultivator. Both blades are extensively used in Taiwan. The blade must be protected from intertwisting to ensure high efficiency and uniform resistance of the plow to soil. Theoretical and calculated cutting angles are found to be 85.88° and 84.28°, respectively, while the theoretical and calculated edge-curve angles are 59.70° and 58.31°. The present data confirmed that the tiller blades developed by local companies are suitable for the plowing environment in Taiwan. In order to reduce …
Modeling And Control Of A New 1/4t Servo-Hydraulic Vehicle Active Suspension System, Jyh-Chyang Renn, Tsung-Han Wu
Modeling And Control Of A New 1/4t Servo-Hydraulic Vehicle Active Suspension System, Jyh-Chyang Renn, Tsung-Han Wu
Journal of Marine Science and Technology
Nowadays, the active suspension is the key technology for vehicles to achieve both ride comfort and control performance. In this paper, a new 1/4T servo-hydraulic vehicle active suspension system is developed and two control schemes are utilized. The first one is a conventional PID controller obtained from Ziegler-Nichols method and the second one is the neural network controller. Though these two controllers are quite simple and not new, it is still worth mentioning that this paper emphasizes on the engineering aspects including the design of a servo-hydraulic test rig, the implementation technology of the controllers and the subsequent experimental study. …
Piv Measurements Of Exit Flow Field Of Centrifugal Fans With Conditional Sampling, Shun-Chang Yen, Jung-Hsuan Liu
Piv Measurements Of Exit Flow Field Of Centrifugal Fans With Conditional Sampling, Shun-Chang Yen, Jung-Hsuan Liu
Journal of Marine Science and Technology
In this research, we have experimented with two centrifugal fans with the same geometrical configuration. These two fans are designed to rotate at different speeds driven with the same voltage. The Particle Image Velocimetry (PIV) method is applied to measure the instantaneous flow fields at the near-exit region. The AMCA 210 wind tunnel is used to find the efficiency and the performance coefficients. The velocity vectors, streamlines, vorticity contours, velocity distributions, flow rate, and performances are also presented and discussed. We find that higher rotation speed yields better efficiency.
Stochastic Chaotic Motion Of Ships In Beam Seas, Li-Qin Liu, You-Gang Tang, Hong-Xia Li
Stochastic Chaotic Motion Of Ships In Beam Seas, Li-Qin Liu, You-Gang Tang, Hong-Xia Li
Journal of Marine Science and Technology
The stochastic chaotic motion and the threshold intensity of the external excitation force for onset of chaos of the ships in random beam waves are studied by the nonlinear stochastic dynamics theory. The random differential equation of ships’ rolling motion is established with considering the nonlinear damping, nonlinear restoring moment and the white noise wave excitation. The random Melnikov mean-square criterion is used to determine the threshold intensity for onset of chaos. The probability density function of the rolling response is calculated through solving the stochastic differential equations by applying the path integral method in the chaotic region. It is …
Study Of The Flow Field And Scalar Transport Of Indoor Ventilating Space Under The Impact Of Coanda Vortex, Je-Ee Ho, Hong-Tsu Young
Study Of The Flow Field And Scalar Transport Of Indoor Ventilating Space Under The Impact Of Coanda Vortex, Je-Ee Ho, Hong-Tsu Young
Journal of Marine Science and Technology
The vortex in the flow field will isolate the space to further reduce the indoor air exchange and convective efficiency. The Coanda vortex accompanied by the inlet jet usually has the most active effect on the flow field. Both its location and scalar size which are primary determined by the strength of the injected flow and the arrangement of inlet; outlet will deeply affect the air-exchange volume, even reduce the available ventilation space. A 2-D turbulent model with SIMPLE method is set up to simulate the air motion of indoors; it can easily describe the working of Coanda vortex in …
Simple: System Automatic Essay Assessment For Indonesian Language Subject Examination, Anak Agung Putri Ratna, Bagio Budiardjo, Djoko Hartanto
Simple: System Automatic Essay Assessment For Indonesian Language Subject Examination, Anak Agung Putri Ratna, Bagio Budiardjo, Djoko Hartanto
Makara Journal of Technology
SIMPLE: System Automatic Essay Assessment for Indonesian Language Subject Examination. Evaluation of study of a student is a very important aspect of an educational process. Evaluation is aimed at measuring the level of student understanding of the given lecture materials. Measuring student understanding of the course material, using essay-type exam, is generally used as the evaluation tool. In this essay-type exam, the student has to answer questions using sentences, whereby choices of possible answers are not indicated. The student has to answer the questions with his/her sentences. The answers may vary, since it reflects the student’s best thoughts of the …
Biodesulphurization Within Natural Gas In Oil And Gas Field, Sri Astuti Rahayu, M. Fierdaus, Syafrizal Syafrizal, M. Udiharto
Biodesulphurization Within Natural Gas In Oil And Gas Field, Sri Astuti Rahayu, M. Fierdaus, Syafrizal Syafrizal, M. Udiharto
Makara Journal of Technology
The presence of sulphur compounds in natural gas can interfere to the quality of natural gas. The decline of combustion gas capacity, metal instrument corrosion in gas piping, and the environmental pollution from gas emission can affect by their presence. Bio-filter is one of the methods that selected to reduce sulphur content in natural gas. A lab scale study of hydrogen sulphide reduction in natural gas had conducted in oil and gas field using bio-filter method. The bio-filter system (±1 L volume) contains an active carbon and thiosulphide medium as a substrate, Thiobacillus thioparus as a single culture of sulphur …
Mechanical Study On Using Of Accr Thermal Conductor At 500 Kv Sutet, Suprihadi Prasetyono
Mechanical Study On Using Of Accr Thermal Conductor At 500 Kv Sutet, Suprihadi Prasetyono
Makara Journal of Technology
Mechanical Study on using of ACCR Thermal Conductor at 500 kV SUTET. At the height of electricity demand increasing recently, circumstance of environment more limited and also expense of high investment, making thermal conductor (conductor thermal resistance) considered to be one of alternative in the electricity transmission bottlenecks. These days it has been developed thermal conductor ACCR (Aluminium Conductor Composite Reinforced) which can operate with temperature up to 240oC, so that making the current carrying capacity being higher than conventional conductor. This research aimed to study load current leading to mechanical characteristic ACCR conductor included tension, length of elongation and …
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
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 …
Sulfonation Of Cptfe Film Grafted Styrene For Proton Exchange Membrane Fuel Cell, Yohan Yohan
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 …
Lower Extremity Mechanics During Cutting Tasks In Different Shoe-Turf Combinations, Rafael Garcilazo
Lower Extremity Mechanics During Cutting Tasks In Different Shoe-Turf Combinations, Rafael Garcilazo
McNair Scholars Research Journal
The demands placed on the lower extremity when performing jumping and cutting maneuvers are depending, in part, on the interaction between the playing surface and the athlete's footwear. Higher demands are likely to result in increased incidence of injury, so for safety reasons it is important to quantify how the shoe-turf interface affects joint loads. The purpose of this study is to compare the forces on the lower extremity while landing and side cutting (rapid direction change at approximately 45 degrees) on artificial football turf with different styles of football cleats.
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
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, …
Construction Of Short-Length High-Rates Ldpc Codes Using Difference Families, Deny Hamdani, Ery Safrianti
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 …
Production Of Medium Chain Length Polyhydroxyalkanoates From Oleic Acid Using Pseudomonas Putida Pga1 By Fed Batch Culture, Sidik Marsudi, Irene K.P. Tan, Seng Neon Gan, K. B. Ramachandran
Production Of Medium Chain Length Polyhydroxyalkanoates From Oleic Acid Using Pseudomonas Putida Pga1 By Fed Batch Culture, Sidik Marsudi, Irene K.P. Tan, Seng Neon Gan, K. B. Ramachandran
Makara Journal of Technology
Bacterial polyhydroxyalkanoates (PHAs) are a class of polymers currently receiving much attention because of their potential as renewable and biodegradable plastics. A wide variety of bacteria has been reported to produce PHAs including Pseudomonas strains. These strains are known as versatile medium chain length PHAs (PHAs-mcl) producers using fatty acids as carbon source. Oleic acid was used to produce PHAs-mcl using Pseudomonas putida PGA 1 by continuous feeding of both nitrogen and carbon source, in a fed batch culture. During cell growth, PHAs also accumulated, indicating that PHA production in this organism is growth associated. Residual cell increased until the …
Optimal Allocation Of Heat Transfer Area For A Refrigeration Plant, Tong-Bou Chang
Optimal Allocation Of Heat Transfer Area For A Refrigeration Plant, Tong-Bou Chang
Journal of Marine Science and Technology
For an internally reversible refrigerant plant, Bejan proposed an optimal way of dividing the area ratio of heat transfer for the hot end and cold end heat exchangers. In the present study, an optimal design of a refrigeration plant has been developed by considering both the external and internal irreversibilities. The internal irreversibility is modeled by a heat bypass which represents the actual internal heat leak and the friction losses due to mechanism movement. A more general formulation than previous study of optimal area-ratio is obtained in this study. For the case of no internal irreversibility, this formulation is exactly …
The Relationship Between The Location Of Obstacle And Indoor Particle Deposition, Je-Ee Ho, Hong T. Young
The Relationship Between The Location Of Obstacle And Indoor Particle Deposition, Je-Ee Ho, Hong T. Young
Journal of Marine Science and Technology
An appropriate ventilation system design not only increases the indoor ventilation effect but effectively improves the particle concentration distribution. The locations of indoor furniture are used to analyze the indoor airflow and particle distribution by numerical skill in this study. Also, a 45 cm × 45 cm × 45 cm chamber is setup as experiment apparatus which is made by acrylic resin board with 16 holes connected to supply air flow. In order to simulate the furniture effect, some wooden blocks are located at the chamber. The temperature and humidity sensors are connected to the data acquisition system with a …
Theoretical Exploration Of Characteristics Of Up-Conversion Materials In Photovoltaics, Joel Bordewyk
Theoretical Exploration Of Characteristics Of Up-Conversion Materials In Photovoltaics, Joel Bordewyk
The Journal of Undergraduate Research
Up-conversion materials can be used to greatly enhance the productivity of photovoltaic nanotechnologies. These materials must convert photons from a low energy to a higher energy to fit within the acceptable range of the solar panel. Software is needed to compute the value of these energy levels and to find molecules that produce these values. It must first be determined if the software has these capabilities and if the results are trustworthy. Naphthalamide has been a molecule of interest and serves as a good starting point for these studies.
Vibration Analysis Of A Boat And Dock, Annicka Gunderson
Vibration Analysis Of A Boat And Dock, Annicka Gunderson
The Journal of Undergraduate Research
A structure is designed to withstand the maximum force that will be applied. In this case a boat dock is examined as a spring system. This exercise uses a typical design for a lake side boat dock, tires for buoys, and an average fishing boat. Vibration analysis can predict when the highest forces will occur. A solution can be found to graph the motion of the dock. In addition to the analytical solution, the MATLAB program is used to visualize the vibrations. With these tools the magnitude and timing of forces can be verified.