bluuebunny/crossref_metadata_2025 huggingface dataset:
Hardness Distribution and Effective Case Depth of Low Carbon Steel after Pack Carburizing Process under Different Carburizer
Authors: Negara Dewa Ngakan Ketut Putra , Muku I. Dewa Made Krisnha , Sugita I. Ketut Gede , Astika I. Made , Mustika I. Wayan , Prasetya Dewa Gde Rudy
Published: July 2015

This research is concerned with the effect of different carburizers on hardness distribution, effective case depth and microstructure of low carbon steel after pack carburizing process. Carburizers to be used were combination of energizer (BaCO3), goat bone charcoal and bamboo charcoal with five different compositions. The specimens were heated to temperature of 950°C, soaked at the temperature for 4 hours and quenched in the water. After the process, microstructures of specimen were observed, the hardness was measured using Vikers method and effective case depths were calculated. The results obtained showed that for all types of carburizer used, the hardness were scattered from surface to the core with lower hardness level. Carburizer composition of 20% BaCO3 + 80% goat bone charcoal produced the highest hardness ( 789.273 HV1) at 0.2 mm from the surface, however, it yielded the lowest effective case depth (0.52 mm). The highest effective case depth of 1 mm was obtained using carburizer composition of 20% BaCO3 + 60% goat bone charcoal + 20% bamboo charcoal. Meanwhile, the original structures of raw material which consist of ferrite and pearlite transformed to hard martensite constituent in the surface after pack carburizing.
Morphological Analyses and Crystalline Structures of Anodic TiO2 Thin Film on Ti6Al4V Alloy Using Phosphate and Calcium Containing Electrolyte under Different Voltage and Calcium Molarity
Authors: Antara I. Nyoman Gde , Gatot K.I. Made , Budiana I. Made , Choi Dae Kue
Published: July 2015

This study was aimed at evaluating morphological and crystalline structures of anodic and hydrothermal titanium oxide thin films formed on Ti6Al4V alloy in a mixture of glycerol phosphate disodium salt (GP) and calcium acetate (CA) solution at various forming environments such as CA molarity and applied voltage. Anodic oxide films were hydrothermally treated and their morphological surfaces, crystal structures and chemical compositions were characterized. It was found that TiO2 film was formed in all surfaces of Ti6Al4V alloy specimen with porous and rough morphology and the crystal structures were mainly anatase. The anodized film morphology and the crystals structure were dependent on CA molarity and anodizing voltage. Increasing CA molarity from 0.15 to 0.30M increased the number and size of micro porous and the intensity of anatase crystals, but further increasing to 0.45M, the number and size did not change and the intensity of anatase peaks became weak. Except in 0.45M-CA, the number and size of micro porous and the intensity of anatase crystals increased gradually with increasing anodizing voltage. Ca-P crystals were precipitated on the surface of hydrothermally treated films. CA molarity associated to the crystal shape while anodizing voltage related to the amount and size precipitated crystals. CA molarity was also associated to the atomic compositions of Ca and P that precipitated on the hydrothermally treated surface film.
Hardness Prediction Based on P-h Curves and Inverse Material Parameters Estimation
Authors: Budiarsa I. Nyoman
Published: July 2015

The Finite Element model of Vickers indentation has been developed. The model was validated against published testing data. An approach to predict the P-h curves from constitutive material properties has been developed and evaluated based the relationship between the curvature and material properties and representative stress. The equation and procedure established was then successfully used in predict the full Vickers indentation P-h curve. FE Spherical indentation models of different radius have been developed and replay file model was developed that is able to produce data of different materials properties. Two new approaches to characterise the P-h curves of spherical indentation have been developed and evaluated. One is the full curve fitting approach while the other is depth based approach. Both approaches were proven to be adequate and effective in predicting indentation P-h curves. The concept and methodology developed is successfully used to predict hardness values (HV and HRB) of materials through direct analysis and validated with experimental data on selected sample of steels. The approaches (i.e. predict hardness from P-h curves) established was successfully used to produce hardness values of a wide range of material properties, which is then used to establish the relationship between the hardness values (HV and/or HRB) with representative stress. This provided a useful tool to evaluate the feasibility of using hardness values in predicting the constitutive material parameters with reference to accuracy and uniqueness by mapping through all potential materials ranges
The Development of Slurry Seal Design with Ordinary Portland Cement Replacement by Low Calcium Fly Ash
Authors: Setyawan Ary , Sarwono D. , Adnan M.S.
Published: July 2015

Slurry Seal is an impermeable non-structural thin layer that is used for pavement maintenance consisting of a cold laid mixture of asphalt emulsion with continuous graded fine aggregate, mineral filler, water and other added ingredients. Ordinary Portland Cement (OPC) as the main filler in the application of slurry seal. Due to the relatively high cement prices and the pollution control for the environment; it is required to maintain the quality of the slurry by using a combination of OPC and LCFA (Low Calcium Fly Ash). This research was conducted to determine the value of consistency, setting time and indirect tensile strength (ITS) of slurry seal containing LCFA. A consistency testing used to obtain optimum moisture content to produce the sample for the rest of the test. The results show that with the addition of 5% water for pre-wetting and subsequently 10% of water content, the mixture provide appropriate consistency as required by highways standard. The time settings also meet the requirements of highways standard between 15 to 720 minutes for all types of mixtures. The mixture with composition of 50% OPC and 50% LCFA is considered as an ideal mixture at the optimum density value of 1.769 g/cm3, porosity of 9.55% and the indirect tensile strength of 30.99 kPa. It could be concluded that fly ash can be used as OPC partial replacement and enhance the properties on slurry seal application.
Hardness, Density and Porosity of Al/(SiCw+Al2O3p) Composite by Powder Metallurgy Process without and with Sintering
Authors: Suarsana Ketut , Soenoko Rudy
Published: July 2015

Al/(SiCw+Al2O3p) composite was a blend of fine aluminum powder serving as a matrix while Silicon Carbid whiskers (SiCw) and Alumina (Al2O3p) as a reinforcement. Powder metallurgy was used for the manufacture of composites according to the shape of the test specimen. Parameter testing was conducted with varied sintering holding time of 1 h, 3 h and 6 h at a sintering temperature of 500°C and 600°C. This study was conducted to know hardness properties, density, porosity and SEM analysis. The results show that the sintering process which has been conducted affects the physical and mechanical properties of the composite. Increased hardness and density occur due to the stronger or more dense interface bonding between matrix and reinforcement which are affected by the increase in the holding time and sintering temprature, where the highest is at 6 hours with 600°C, while the porosity decreases inversely proportional to the density and the hardness that occur in composite materials.
Boiling Phenomenon of Tabulate Biomaterial Wick Heat Pipe
Authors: Septiadi Wayan Nata , Putra Nandy
Published: July 2015

This research purposed to know the performance of heat pipe using wick made from biomaterial. Biomaterial (Coral) is the porous media which has the relative homogenous and small porous structures. The homogenous structures and the small biomaterial have the better capillarity and could be used as wick to circulate condensate in heat pipe. The heat pipe made from copper pipe with 50 mm in length and the inside and outer diameter was 25 mm and 24 mm in each, with the wick as thick as 1 mm made from Tabulate. Heat sink was adhered to the condenser part of heat pipe as wide as 637.5 cm2. The study was the observation of phenomena in porous media boiling between biomaterials with solid copper, in which the observations were made by using High Speed ​​Video Camera (HSVC). Tabulate biomaterial has the porous structure which quite homogeny and the best capillary energy. The biomaterial as wick heat pipe could keep the condition of heat pipe from easily reachs the transition condition.
Fluidization Characteristic of Sewage Sludge Particles
Authors: Winaya I. Nyoman Suprapta , Hartati Rukmi Sari , Sujana I. Nyoman Gde
Published: July 2015

The main objective of this study is to determine the basic characteristics of fluidization using sewage sludge particle as non-visual phenomena which can then be modeled physically and numerically with the program of Computational Fluid Dynamic (CFD). CFD modeling using Eulerian model incorporating the kinetic theory for solid particles was applied to the gas-solid flow at various superficial velocities for different particle sizes. The transfer momentum was calculated using Syamlal-O'Brien drag function and Eulerian multiphase model was used for analysis. Two-Dimensional computational domains discretized using rectangular cells (Quad), made within the 20 iteration steps of 0,001s. The gas velocity is found to be the ​​the most important factors that influence the formation process of fluidization; by increasing the rate of fluidization the bed expanse occurs higher as well the time of onset fluidization is shorter. The phenomenon can be explained well by modeling and simulation.
Magnetic Camera and its Applications in Aging Aircraft, Express Train and Pipelines for Green Technology
Authors: Lee Jin Yi , Kim Jung Min
Published: July 2015

Operation of the corresponding large machine is not allowed during the regular NDT period. Therefore, reducing the test period and extending the test frequency, i.e., lowering the machine stoppage time due to an inspection is a very important technique for efficient energy usage. For this reason, IT-based real-time non-destructive testing (IT-NDT) technology has been being developed. This presentation reports on a magnetic camera, which is one IT-NDT technology, including the up-to-date experiences.
Buckling Analysis on Pechiko Field of Fixed Offshore Platform in Makassar Strait
Authors: Alie Muhammad Zubair Muis , Palentek Y.R. , Sesa D.G.
Published: July 2015

One of the most important criterion in the design of fixed offshore platform is to have strength from applied loads which is acting perpendicular to jacket leg section such as axial compression.The axial compressive load acts vertically downward to jacket legs and the deformation on the jacket legs in horizontal direction due to this load is called buckling. In the present study, buckling analysis on pechiko field of fixed offshore platform is performed using Finite Element Analysis (FEA). The fixed jacket platform namely tripod and tetrapod are taken as the object of the analysis. Only the axial compressive load is used in the analysis and the boundary conditions are assumed to be fixed both tripod and tetrapod at the bottom seabed. As a fundamental case, buckling analysis is carried out in plane-section (2D analysis), then the result obtained by FE analysis is compared with the analytical solution.It is found that the result obtained by FE analysis for the critical buckling load is in good agreement with the analytical solution, and the applicability of FE analysis is further used to investigate the deformation of 3D model.
Three Wheel Bike as Physical Therapy Equipment for Post-Stroke Patient
Authors: Batan I Made Londen , Rodika Rodika , Riva'i Muhamad
Published: July 2015

Three wheel bike as a physical therapy equipment for post-stroke patients was designed with length of 1937 mm, 1010 mm in width and height of 905 mm. The bike is designd ergonomic and can be driven by rider foot or hand simultaneously. By using CATIA software the strength of material bike frame was analyst to support 100 kg of load. The design is realized into a prototype. The performance of bike prototype is tested, and the result sows that the function of bike mechanisme is fulfilled. By 10 respondents, who have a standard body mass index, the pedal test was conducted, and the result indicates that, the higher the speed of the pedal, the higher the energy consumption to pedaling. Leg tension muscles is measured by leg-dynamometer before and after pedaling, and the result shows the tension muscle is proportional to the increase of pedal speed. In order to evaluate the ergonomic aspect of bike design, the risk angle of extrem position of body during cycling are measured by goneo-set. By RULA method the risk of injury value of rider body is calculated while pedaling, and the result showed that 70% of respondents have a value of risk injury 2, while 30% had a value of 3. It means that, the bike design is ergonomic and comfortable to ride. In oder to evaluate the benefits of disigned bike, the pedal test is conducted by 4 post-stroke patients for 30 days periodical once every 3 days. The result shows that during 1 month exercise, the average number of cycling to pedal increase up to 100%. This means that the ability of post-stroke patients to pedal the bike increase significantly. That result showed that the bike design is useful as a tool for physical therapy post-stroke patients.
Role of Risk Management in Effective Maintenance
Authors: Yuniarto Hari Agung , Paristiawati Putu Fransisca
Published: July 2015

Every manufacturer requires plant maintenance. Knowing that an effective maintenance system increases sales and decreases maintenance cost of the production facility, maintenance is deemed to be substantial contributions to improved plant profit changing from a necessary evil to a profit centre. Unfortunately, this sometime is a far cry from reality. This paper offers a concept of incorporating risk into maintenance and development of a Decision Support System (DSS) for decision makers in the maintenance department. It helps prioritise critical equipment and select its associated maintenance strategy for optimum results. The results of validating the devised AHP-based software package in a case study company in Indonesia are promising since the company successfully gains 3.65% in Net Line Efficiency and 3.13% in Gross Line Efficiency as well as enjoys an advantage over 4.56 points decrease in Operation Performance Loss.
Model of Carbon Dioxide (CO2) Emission from Motorcycle to the Manufactures, Engine Displacement, Service Life and Travel Speed
Authors: Mulyadi Agah Muhammad , Gunarta Samsi
Published: July 2015

By the end of 2012 the population of motorcycle reached 77.7 million units with their average composition on the road reached 82%. The number of motorcycles produce CO2 emissions which have a negative impact on global warming. Global warming occurs because the greenhouse effect of CO2 in the atmosphere absorb heat energy and obstructed the heat from the atmosphere to the higher surface.The data collected in this research is the data of motorcycles fuel consumption. The method of data processing by converting the fuel consumption data to CO2 emissions using the equation of the Clean Development Mechanism (CDM) AMS-III Methology. The purpose of this research is to create models of CO2 emissions on a motorcycle against several influential independent variables such as manufacture, service life, engine displacement (cc) and travel speed. Method analysis using correlation and regression analysis.Based on the regression analysis, the best combination that produces the lowest value of CO2 is a motorcycle with a combination of manufacture number 2, 5 years service life, engine displacement of 111-149 cc and travel speed of 60 km/h. Whereas from the the correlations analysis obtained the motorcycle of manufacture number 2 able to decrease up to 15% CO2 and motorcycles with engine displacement of 111-149 cc is able to reduce CO2 emission from 17% to 43%. While the service life of one year to six years resulting CO2 emissions which relatively similar with only difference of 15%. Furthermore, the travel speed of 60 km/h able to reduce CO2 emissions by up to 62%.
The Influence of Distance Variation between Rings with Sloping Position on the Cylinder Surface to Drag Coefficient
Authors: Tista Si Putu Gede Gunawan , Ghurri Ainul , Wijaksana Hendra
Published: July 2015

There are so many equipment using cylinder in its application, such as bridge support column, smoke chimney, pole pillar of offshore oil drilling etc. When those kind of equipment is affected by air flow continuously, it would reducing the strength of those equipment construction. This strength reduction is caused by the drag force that is emerged due to the air flow and its direction are having the same direction with flow direction. So that it is necessary to do something to reduce the drag, one of it is by adding the rectangular ring at the cylinder surface. The rings is placed at the cylinder surface in 100 sloping position and then its ring distance would be varied. The aim of this research is to discover the influences of distance variation between the ring with sloping position on the cylinder surface to the drag coefficient. This research is conducted in the wind tunnel that consist of blower, pitot pipe, U manometer, inclined manometer, digital weight, cylinder, quadrangular rings (attached on the cylinder). The cylinder is placed in vertical position within the distance between the rings is varied as L/D = 0.5, 0.67, 0.83, 1.00, and 1.17. The Reynold number based on silinder diameter D = 60 mm is Re = 3.64 X 104 . Pressure distribution is determined by measuring cylinder surface pressure at 36 points with 100 interval. The result of this research showed that the lowest drag coefficient value occurs at the distance between the ring of L/D = 0.5 is 0.485. The large decreasing of the drag coefficient compare to without rings is 43.5%.
Experimental and Theoretical Investigation of Bolted Bamboo Joints without Void Filled Material
Authors: Oka Gusti Made , Triwiyono Andreas , Awaludin A. , Siswosukarto S.
Published: July 2015

An experimental and theoretical are presented to calculate the load capacity of shear single connection (SSC) and shear double connection (SDC) without void filled material. The model presents an extension of the Johansen theory for bamboo connection type, also known as the European Yield Model (EYM). The bamboo of Gigantchloa atroviolacea of the most popular as non-wood has been used as a construction material in some region of Indonesia. The uniqueness bamboo is bamboo non-homogen material, sectional shape non-prismatic, the straighthness stems not same, on the culms guiler node and a cross-section in hollow. The diameter of Gigantochloa atroviolacea bamboo used in this study is ranged from 70 to 90 mm. The diameter of bolt is 12.7 mm. The connection strength can be determined with theoretical and eksperimental. Application theory of the European Yield Model could be developed into theory of connection laterally strength of bamboo without void filler material. Factors that affected of connection laterally strength is bamboo thickness, bolt diameter and spesific gravity. The equation four of connection strength base on European Yield model can calculated of according to yield model of accurred. The connection strength is specified from the value smallest of the equation four of connection yield models.
The Significant Importance to Measure Road Safety
Authors: Caroline Sutandi A.
Published: July 2015

Although road safety is a huge problem in develop and developing countries, road safety measures are not implemented seriously yet, especially in developing countries. Road safety measures are important to be defined and implement before, during, and after road accident occur. Furthermore, evaluation is needed after implementation of road safety measures, in order to find out whether safer road is better or not. The aim of this study is to develop road safety measurement based on existing road condition, traffic condition, accident happened, before and after implementation of road safety measures. Road safety value by indicators as the results should be implemented consistently and hard effort of all stakeholders should be done to provide safer road. Results of this study are important to reduce number and severity of casualties and moreover lead to safer road.
Method of Bending Stiffness Parameter Identification of Stay Cable
Authors: Du Hong , Liu Da Yang , Huang Fu Wei , Liao Jing Bo
Published: July 2015

In order to solve the problem of bending stiffness parameters identification of practical stay-cable, and provide bending stiffness correction for tension measurement. A method to identify cable bending stiffness parameters is proposed, and its basis theory established in paper. The method was applied to Xiazhang Sea-Crossing Bridge, the results showed that: Identification bending stiffness ratio is between 0.33 to 0.54 for relatively short cables of South Branch Bridge, and it tends to decrease with increase of cable length and force. However, the identification bending stiffness is close or equal to 0 EImax for relatively long cable of North Branch Bridge. It testified that the effect of bending stiffness for long cable tension is small in engineering.
Numerical Simulation for Extrusion Process of Thin-Wall Aluminum Profile with Large Flakiness Ratio and Optimization Die Design
Authors: Ma Xiao Fei
Published: July 2015

The numerical simulation of a thin-wall aluminum profile was introduced. Then the velocity and temperature of the extrusion process were given. A die design optimization method was proposed by the velocity analysis. After optimization, a profile with uniform exit velocity was gain. Finally, a method for this profile die design was summarized.
Thin Film Solar Cell: Characteristics and Characterizations
Authors: Hossain Mohammad Kamal
Published: July 2015

In recent decades, due to some urgent and unavoidable issues, such as increasing energy demand, climate change, global warming, etc., the R&D of renewable energies have become inevitable to pave way the sustainable development of human society. In this regard, solar power is widely considered as the most appealing clean energy since there is no other one being as abundant as the sun. The amount of solar energy reaching our earth within one hour equals to the total annual energy need of all of humankind. Since the energy resources on Earth are being exhausted, solar energy have to serve as the main energy source in coming century and beyond. The photovoltaic solar cells developed so far have been based on silicon wafers, with this dominance likely to continue well into the future. The surge in manufacturing volume as well as emerging technologies over the last decade has resulted in greatly decreased costs. Therefore, several companies are now well below the USD 1 W−1 module manufacturing cost benchmark that was once regarded as the lowest possible with this technology. Thin-film silicon, such as hydrogenated amorphous silicon (a-Si), microcrystalline silicon (mc-Si) and related alloys, are promising materials for very low-cost solar cells. Here in this article, a brief description of thin film solar cell technologies followed by deferent state-of-art tools used for characterizing such solar cells are explored. Since characteristics of thin-film solar cells are the main ingredient in defining efficiency, the inherent properties are also mentioned alongside the characterizations.
Chemically Treated Submicron Illite Clays for Product with Improved Strength
Authors: Grase Liga , Mezinskis Gundars , Vitina Inta
Published: July 2015

A variety of industrial minerals, such as kaolinite, feldspars, and etc., have been used as solid raw materials in the geopolymerization technology. The illite-containing raw material in this study was obtained by the use of sedimentation method. Clay and dust fractions was subjected to the treatment with NaOH alkaline solution and afterwards treated at different temperatures. Results obtained by X-ray diffraction, Scanning electron microscopy, nitrogen adsorption method confirmed the usability of Liepas deposit homogenized gray and red clays for possible realization of geopolymer method.
Increase of Electrical Conductivity due to Chemical Reduction of Pre-Exfoliated Graphene Oxide by Sodium Borohydride
Authors: Berzina Astrida , Tupureina Velta , Orlovs Raimonds , Saharovs Dmitrijs , Bitenieks Juris , Knite Maris
Published: July 2015

Graphene oxide (GO) reduction is a promising way for graphene large scale synthesis. Pre-exfoliated graphite was oxidized and reduced. The material was compared to commercial graphene oxide and its reduced sample. The reduction process of graphene oxide is accomplished using sodium borohydride (NaBH4) with variable-valence metal ion – cobalt – assistance. The reduced graphene oxide (RGO) was characterized by Raman spectroscopy. The particle size and suspension stability were determined. Electrical conductivity measurements of GO and RGO samples have been done in temperature range from-150°C to 85°C. Pre-exfoliation effect was determined.
Increase of Photoelectric Response of Ge Nanocones Formed on SiGe by Laser Radiation
Authors: Gorb Alla , Korotchenkov Oleg , Kuryliuk Vasyl , Medvid Artur , Nadtochiy Andriy , Podolian Artem
Published: July 2015

Irradiation of SiGe-on-Si structures by pulsed Nd:YAG laser with intensities 1.0 MW/cm2 leads to the formation of Ge nanocones. As a result increases the surface photovoltage (SPV) signal up to 10 times. The SPV decays do not speed up with the radiation, thus indicating that the laser treatments do not cause an increase in the concentration of recombination centers at interfaces. Therefore the fabrication technique proposes here may be considered to be an effective approach of producing cost-competitive photosensors based on SiGe/Si.
Laser-Induced Formation of Periodic Structures on the Metal Surfaces and Surface Plasmons Excitation
Authors: Dmitruk Igor , Zubrilin Nikolai , Berezovska Nataliya , Dombrovskiy Olexandr , Balanets Sergiy , Grabovsky Eugene , Blonskiy Ivan
Published: July 2015

Quasiperiodic microstructures are formed on the surfaces of metals under irradiation with high-power femtosecond laser pulses. Interpretation of microstructures as a result of interference of the incident plane wave and surface waves leads to the logical conclusion about the relationship of dislocations in the interference fringes with optical vortices in surface wave. Other peculiarities observed in these structures contain different periods and nanogranular fine structure. It is demonstrated that such laser-induced structures can find applications for surface plasmon excitation and surface enhanced Raman scattering.
Synthesis of Chlorine-Silicate Phosphors for White Light-Emitting Diodes
Authors: Keskinova Mariia V. , Ogurtsov Konstantin A. , Sychov Maxim M. , Kolobkova Elena V. , Turkin Igor A. , Nakanishi Yoichiro , Hara Kazuhiko
Published: July 2015

A novel approach to obtaining chlorine-silicate phosphors is developed. This method based on the synthesis in a microwave furnace is shown to provide the following advantages compared with the conventional procedures: (a) “warmer” color, (b) increased brightness, (c) significantly reduced processing time and cost. Phosphors are suitable for white LED and cathodoluminescent lamp applications.
Efficiency Analysis of Gas Turbine Combined-Cycle Fed with Synthetic Natural Gas (SNG) and Mixture of Syngas and SNG
Authors: Chiu Hsiu Mei , Chen Po Chuang , Chyou Yau Pin , Wang Ting
Published: July 2015

The effect of synthetic natural gas (SNG) and mixture of syngas and SNG fed to Natural Gas Combined-Cycle (NGCC) plants is presented in this study via a system-level simulation model. The commercial chemical process simulator, Pro/II® V8.1.1, was used in the study to build the analysis model. The NGCC plant consists of gas turbine (GT), heat recovery steam generator (HRSG) and steam turbine (ST). The study envisages two analyses as the basic and feasibility cases. The former is the benchmark case which is verified by the reference data with the GE 7FB gas turbine. According to vendor’s specification, the typical net plant efficiency of GE 7FB NGCC with two gas turbines to one steam turbine is 57.5% (LHV), and the efficiency is the benchmark in the simulation model built in the study. The latter introduces a feasibility study with actual parameters in Taiwan. The SNG-fed GE 7FB based combined-cycle is evaluated, and the mixture of SNG and syngas is also evaluated to compare the difference of overall performance between the two cases. The maximum ratio of syngas to SNG is 0.14 due to the constraint for keeping the composition of methane at a value of 80 mol%, to meet the minimum requirement of NG in Taiwan. The results show that the efficiency in either case of SNG or mixture of SNG and syngas is slightly lower than the counterpart in the benchmark one. Because the price of natural gas is much higher than that of coal, it results in higher idle capacity of NGCC. The advantage of adopting SNG in Taiwan is that it could increase the capacity factor of combined-cycles in Taiwan. The study shows a possible way to use coal and reduce the CO2 emission, since coal provides nearly half of the electricity generation in Taiwan in recent years.
Oscillation Phenomenon of the Cell Performance for an Anode-Supported Solid Oxide Fuel Cell with a Low-Porosity/High-Thickness Anode Structure
Authors: Kao Wei Xin , Lin Tai Nan , Chang Yang Chuang , Lee Maw Chwain
Published: July 2015

The anode-supported solid oxide fuel cell (SOFC) with low-porosity anode structure is fabricated and the electrochemical characteristics are investigated. The electrochemical characterization of the cell shows a periodic oscillation phenomenon of the cell voltage under the constant current density operation. The low-porosity anode structure results in the decrease in the effective diffusion coefficient and the accumulation of water vapor. The cell voltage oscillation is mainly caused by the concentration polarization as well as the boundary migration of the reaction zone. The profound influence on the concentration polarization can be observed when the cell test is executed with operation condition of higher current density, lower hydrogen concentration, and lower hydrogen flow rate in the anode side.
Viscosity Effects of Spray Characteristics in Air-Blast Atomizer
Authors: Hsu Tien Chiu , Yang S.I.
Published: July 2015

Coal is currently the most widely used and most abundant fossil fuel in the world. It is primarily used for generating electricity at power plants. However, due to problems of pollution and energy consumption, importance has been placed on the development of clean coal technology. Coal-water slurry (CWS), consisting of fine coal and water mixture, is a liquid fuel used to replace heavy fuel oil for boilers and entrained flow gasifiers. Since CWS is a liquid with high viscosity and regular atomizing burners are designed for the use of fossil fuels with low viscosity, it is necessary to design high efficiency atomizing burners specific for CWS. As viscosity is a key factor for atomization characteristics, we used silicon oils of different viscosity as the testing liquids, to study the effect of different atomization parameters on the atomization characteristics. Our results show that, when the gas to liquid ratio (GLR) is high, the existing particle velocity at the central axis is lower than low GLR condition; likewise, the velocity at radial positions is higher of the high-viscosity case. The velocity also increases as the radial distance further increases away from the axis. And decrease as the GLR increases. On the other hand, the distribution of the velocities does not change after the radial distance reaches a certain limit. This limit decreases as the axial length increases. Increasing viscosity increases the inertial force of the liquid fluid, so the momentum of the atomization gas needs to be increased for it to generate enough shear stress on the fluid and to enhance the atomization characteristics.
A Numerical Simulation Study on Machining Performance for Front Face Circular Grooving Using Special Structure Milling Cutters — Part 1: Simulation Method and Examination of Machining Capacity
Authors: Qiu Hua
Published: July 2015

This paper proposes a simple and convenient numerical simulation approach to examining the characteristics and machining capacity of the manufacture process to machine a front face circular groove on a multi-tasking machine tool by a side milling cutter with special structure. In the first part of the paper, the simulation method is explained and then based on the simulation results, several important problems in applications are discussed such as how to design the cutter profile and determine the cutter position in grooving. Furthermore, an improved process is also developed for correctly machining a groove with specific profile in the required shape.
A Numerical Simulation Study on Machining Performance for Front Face Circular Grooving Using Special Structure Milling Cutters — Part 2: Simulation Results and Discussions for Machining a Groove with Rectangular Sectional Profile
Authors: Qiu Hua
Published: July 2015

This paper proposes a simple and convenient numerical simulation approach to examining the characteristics and machining capacity of the manufacture process to machine a front face circular groove on a multi-tasking machine tool by a side milling cutter with special structure. In the second part of the paper, the practicability of the process to machine a groove with rectangular sectional profile is discussed based on the simulation results, and then an improved process is developed for correctly machining the groove profile in the required shape. Furthermore, the effect of cutter feed motion on the profile precision of machined groove is studied; at the same time, a main disadvantage of the process as a finishing cutting method is also identified.
A Study on Tool Damage of Threading Tap in Screw Cutting of Stainless Steel 15-5PH
Authors: Hayashi Jinno , Okuda Koichi , Kodama Hiroyuki
Published: July 2015

In this study, the screw cutting experiments of stainless steel 15-5PH was carried out by employing the tapping center in order to investigate the tool damage of threading tap tool. Mainly, the effect of the machining conditions and the ground chamfer shape of tap tool on the thrust force and the tool wear were discussed. As a result, it was found that the thrust force was strongly influenced by the ground amount of tap tool chamfer. Especially, large change of thrust force occurred when the tap tool engaged to the pilot hole and returned out of hole.
Acidic Treatment of CaO-Based Materials for Medium-High Temperature CO2 Capture
Authors: Lin Kuo Hsin , Chang Po Hsueh , Yu Ching Tsung , Chen San Yuan
Published: July 2015

In this work, a series of CaO-based materials for medium-high temperature (500-800 °C) CO2 capture were synthesized from limestone by acidic treatment. In order to enhance its thermal stability, CaO-based materials were modified with Al(NO3)3. With various stirring time of 24, 48 and 72 hours, three types of CO2 capture sorbent were synthesized, named LA24, LA48 and LA72, respectively. TGA results showed the CaO-based materials were activated in the CO2 capture reaction of temperature range of 500-800 °C. LA24 exhibited the best CO2 capture capacity of 53.8 wt % as well as stability of 93.2 % after 10 cycles test. Furthermore, all of the modified CaO-based materials showed good thermal resistance upon 900 °C. It was consistent with expectation by the contributions of alumina coexistence with calcium oxide. XRD results indicated that CaO dominated in the diffraction spectrum before capturing CO2, and a side diffraction peak of Al2O3 was also observed. The characterization of CaO-based materials was also investigated by BET and SEM, respectively.
Basic Study on Thermo Chemical Turning Method for Metal Bonded Diamond Wheels
Authors: Nagao Kazuma , Yamada Keiji , Sekiya Katsuhiko , Tanaka Ryutaro , Yamane Yasuo
Published: July 2015

In this paper, a new truing method is proposed instead of the conventional mechanical truing that has low truing rate for metal bonded diamond grinding wheels. In the proposed method, the metal-bond diamond grinding wheel is rubbed by a steel truer rotating at high speed. Generated frictional heat increases the oxidization and the diffusion of carbon into the steel truer, then diamond grains are thermally attrited on the wheel surface, so that the machinability of wheel is improved. Subsequently, high truing rate is achieved by mechanical truing with abrasive stones. These experiments are conducted using bronze bonded diamond abrasive stones and stainless steel truers, and the relation between truing resistance, truing temperature, and truing rate are investigated. The truing temperature is measured using the thermo couple embedded in the truer. The thermo couple consists of the steel wire embedded and the bronze which is the bonding material of the abrasive stone. The surface profiles of abrasive stones are measured by scanning stylus before and after truing, then the removal volume of abrasive stones is derived from these profiles. Truing rate is also obtained from the removal volume and the truing time. Experimental results for diamond abrasive stones are as follows: The waviness of bronze bond is decreased by proposed truing method. Truing rate is increased as truing resistance and truing temperature increase.
Damage of PVD-Coated Cutting Tools Due to Interrupted Cutting of Ni-Based Superalloys
Authors: Koseki Shuho , Inoue Kenichi , Uehara Kazutake , Hiroshi Usuki , Yoshinobu Masahiro , Tanaka Ryutaro , Hagino Masahiro
Published: July 2015

Ni-based superalloys are typically difficult-to-cut materials. During machining, the cutting forces and temperatures of these superalloys are generally higher than those of other materials. Therefore, the tool life of the coated carbide cutting tools used for superalloy machining is shortened. This study evaluates the damage of the coated end mills during interrupted cutting of alloy 718 and finds the coating properties necessary for improved cutting of Ni-based superalloys. Damage of the PVD-TiN-coated cutting tools was observed by scanning electron microscopy and transmission electron microscopy of the surfaces and cross sections. In addition, friction forces were measured during turning for some coatings, and hardness of the coatings was measured after annealing. Plastic deformation of the coating and crack formation was shown to occur at the coating cross section. In addition, we determined that the major factor for the damage was high friction force between the coating surface and work material at high temperatures. In summary, coatings with stability at high temperatures and low friction forces during machining can reduce the damage of coated cutting tools, thus increasing the tool life.
Development of the Local Polishing Technique for Single-Crystal SiC Wafer
Authors: Nagae Shin , Kubota Akihisa , Touge Mutsumi
Published: July 2015

We have developed a novel polishing technique by scanning a small magnetic tool in hydrogen peroxide solution for smoothing a 2-inch SiC wafer. Obtained results show that the surface roughness in almost areas on the 2-inch SiC wafer is improved markedly. Our proposed method effects a dramatic improvement in a surface microroughness from 0.699 nm Rms to 0.079 nm Rms.
Effect of Cutting Force Control on Cutting Characteristics of CFRP in Diamond Saw Cutting
Authors: Doi Yuki , Kondo Yasuo , Sakamoto Satoshi , Yamaguchi Kenji
Published: July 2015

We examined the relation between the cutting force and the cutting characteristics of CFRP in diamond saw cutting. When a larger cutting force was applied, the cutting had been propagated with a mixed mechanism of the cutting by cutting edges and the cleaving of carbon fiber by shear force. While a good cutting surface was formed in the case of cutting with less than 23 N of cutting force. In this condition, the cutting had been propagated only by the cutting with cutting edges.
Effects of Supplying Oil Mist and Water Mist with Cold Air on Cutting Force and Temperature in End Milling of Difficult-to-Cut Materials
Authors: Okada Masato , Nikawa Makoto , Tanaka Ryutaro , Asakawa Naoki
Published: July 2015

This paper discusses the cutting temperature and cutting force in end milling difficult-to-cut materials cooled with several types of mists and low-temperature air. The cutting tool was a throwaway end mill with a carbide tip coated with titanium aluminum nitride. The Ti-6Al-4V titanium alloy and AISI D2 hardened steel were used as workpieces. The tool flank temperature and cutting force were measured simultaneously during side milling. The temperature was measured using a two-color pyrometer with an optical fiber. Oil mist and water mist from a mist generator were supplied to the cutting point along with cold air at approximately -27 °C. Compared with dry cutting, the cooling effects of supplying an oil mist and/or cold air were less than for other supply conditions in titanium alloy cutting. However, when water mist was added, the tool flank temperature clearly decreased. The cutting force increased for cases that included water mist. The adhesion of the titanium alloy to the cutting edge of the worn tool was significantly suppressed by supplying water and oil mist with cold air. Tool flank wear also decreased under those lubrication conditions.
Machinability Evaluation of Inclined Planetary Motion Milling System for Difficult-to-Cut Materials
Authors: Tanaka Hidetake , Yoshita Toma
Published: July 2015

CFRP and Titanium alloy, which are known as difficult-to-cut materials have been widely used as structural material in aviation industries. The orbital drilling is one of an effective drilling technique for the industries. However this technique has some disadvantages such as increase of cutting force due to cutting with tool center point, inertial vibration generated by revolution and high installation cost. In order to improve the disadvantages, we have invented a new drilling technique which is called inclined planetary motion milling. The inclined planetary motion milling and the planetary mechanism drilling has two axes of cutting tool rotation axis and revolution axis. Cutting tool rotation axis of the orbital drilling is moved parallel to the revolution axis in eccentric. On the other hand, in the case of the inclined planetary motion milling, eccentric of the cutting tool rotation axis is realized by inclination of a few degrees from the revolution axis. Therefore, the movement of eccentric mechanism can be reduced by comparison with the orbital drilling because inclined angle is smaller than eccentricity of the cutting tool tip. As a result, eccentric mechanism can be downsized and inertial vibration is reduced. In the study, a geometrical cutting model of inclined planetary motion milling was set up. The theoretical surface roughness of the inside of drilled holes by use of two types cutting tool geometry were calculated based on the model. And cutting experiments using the new prototype for CFRP were carried out in order to evaluate the effect on machinability with change of cutting point atmosphere. In addition, optimal cutting condition was derived according to cutting experiments for titanium alloys utilizing the orthogonal array.
Near-Dry Machining of Titanium Alloy with MQL and Hybrid Mist Supply
Authors: Wakabayashi Toshiaki , Kuhara Junji , Atsuta Toshifumi , Tsukuda Akira , Sembongi Norio , Shibata Junichi , Suda Satoshi
Published: July 2015

Near-dry machining attracts increasing attentions for environmental and economical benefits, and MQL machining has been recognized as the most representative near-dry method. It is highly successful in machining of most ordinary steels, and synthetic biodegradable polyol esters play a significant role as an effective cutting fluid with a very small amount. Recent concern for environmentally friendly manufacturing further encourages the attempts at applying near-dry operations to machining of difficult-to-cut materials. Since titanium alloys are typical difficult-to-cut materials, this paper investigates the cutting performance of various near-dry methods in turning of a titanium alloy from the view point of elongating the tool life. Those near-dry methods include regular MQL and hybrid mist supply operations, where the hybrid mist is a mixture of MQL mist and coolant mist which is atomized water-soluble cutting fluid. The regular MQL operation provided considerably long tool life compared with that of dry machining and the hybrid mist operation showed the possibility of making the tool life longer. The cutting performance was largely influenced by the type of MQL lubricants. In particular, a synthetic polyol ester lubricant having low viscosity indicated the successful cutting performance when it was combined with the coolant mist supply in the hybrid mist application.
Stability of Adhered Material to the Cutting Edge of a Cermet Insert in Turning of an Austenitic Stainless Steel
Authors: Sekiya Katsuhiko , Watanabe Sachio , Yamada Keiji , Tanaka Ryutaro , Yamane Yasuo
Published: July 2015

Behavior of the material adhered to the cutting edge of a cermet insert was evaluated based on the profile of the machined surface in continuous turning of an austenite stainless steel SUS304. Height of the adhesion material decreased rapidly with increase of the cutting speed from 10m/min to 20m/min. The behavior of the adhered material was more stable than we expected. The adhered layer near the cutting edge was very stable, while the growth or breakage of the adhered material happened on the surface of the stable layer.
The Research of FPGA-Based Short Current Protection for Micro Electrochemical Machining
Authors: Shiu Chih Cheng , Wu Wen Chieh , Huang Ping Hung
Published: July 2015

During micro electrochemical machining process, the gap between tooling and workpiece is dynamically and mutually influenced by multiple machining parameters, which include machining voltage, feed rate, electrolyte flow rate and others. Once inter-electrode gap could not be kept easily with a stable distance due to spark or short-circuit situation maybe happened to damage the cathode. Hence, it is needed to have a real-time protection function embedded within the μECM machining controller. The study of the short-circuit protection module for electrochemical machining is based on field programmable gate array (FPGA) system architecture. The advantages of the digital logic FPGA chips are programmable, high-response and stable operation, custom development and combination of multiple functions with Silicon Intellectual Property. It can achieve special process control or operation analysis logic to meet specific application requirements process equipment control, logic processing and signal analysis. Through the design and application technology of the digital logic FPGA chip, we can develop customized and combine of multiple functions with Silicon Intellectual Property. These silicon intellectual properties combined with the soft-core embedded processors can form the system on programmable chip control module. With a variety of Silicon Intellectual Properties restructuring integration and use of FPGA programmable features that can programmable short-circuit protection logic for electrochemical machining. This module combines power signal capture circuit device, and continuing to capture current signals during electrochemical machining process. The current signals via analog to digital converters and digital filtering, and based on the selection of the short-circuit logic electrochemical determine whether the establishment of short-circuit conditions. When a short circuit occurs, the module can react immediately turn off the power supply, to protect the machining electrode and enhance precision machining.