bluuebunny/crossref_metadata_2025 huggingface dataset:
Intelligent AGV Control of Autonomous Decentralized FMS by Oblivion and Memory
Authors: Yamamoto Hidehiko , Yamada Takayoshi
Published: September 2010

This paper describes a method to control Autonomous decentralized Flexible Manufacturing System (AD-FMS) by using a memory to determine a priority ranking for competing hypotheses. The aim is to increase the reasoning efficiency of a system the author calls reasoning to anticipate the future (RAF) which controls automatic guided vehicles (AGVs) in AD-FMSs. The system includes memory data of past production conditions and AGV actions. The system was applied to an AD-FMS that was constructed on a computer. The results showed that, compared with conventional reasoning, this reasoning system reduced the number of hypothesis replacements until a true hypothesis was reached.
Micro Incremental Forming Characteristics of Stainless Foil
Authors: Sekine Tsutomo , Obikawa Toshiyuki
Published: September 2010

Single point micro incremental forming (SPMIF) was applied to the forming of a meso-scale pyramid. A type 304 stainless foil with a thickness of 8 μm and a household aluminum foil with a thickness of 12 μm were used as blanks. It was found that the elongation of stainless foil was relatively large in SPMIF although it is negligibly small in tensile test. Consequently, stainless foil exhibited larger ratio of elongation in SPMIF to that in tensile test than the ratio of aluminum foil. The enhancement of formability of stainless foil in SPMIF was discussed from a viewpoint of martensitic transformation. The surface condition associated with the process of SPMIF was inspected through AFM diagnosis.
Manufacturing of High-Grade Micro Components by Powder Injection Molding
Authors: Piotter Volker , Plewa Klaus , Mueller Tobias , Ruh Andreas , Vorster Elvira , Ritzhaupt-Kleissl Hans Joachim , Hausselt Juergen
Published: September 2010

Powder injection molding (MicroPIM) has a considerable potential for the production of high-value metal and ceramic micro components. This does not only apply to technical aspects but, due to the deployability of mass production, also to economic ones.
The current status can be summed up by the following key data: latest trials revealed smallest struc-tural details in the 10µm range or lower. Theoretical densities of up to 99% were achieved depend-ing on the particular powder applied. Typical materials processed are metals (Fe, Cu, 316L, 17-4PH, W and W-alloys etc.) or ceramics (aluminum/zirconium oxide etc.). Best surface qualities were obtained with ultrafine or even nano-doped ceramic powders.
Another major line of development is multi-component or assembly injection molding. These proc-esses do not only reduce assembly expenditure, but also allow for the use of new functional material combinations. Interesting examples are ceramic micro heating elements or gear wheel/shaft samples which can be performed as fixed or movable combinations. Micro inmold-labelling using PIM feed-stocks offers further promising opportunities.
Process and Material Property Effects in the Progressive Forming of Micro-Pins
Authors: Lim Samuel C.V. , Aue-U-Lan Yingyot , Atsushi Danno , Chew Mei Qian , Wong Chow Cher
Published: September 2010

A progressive forming process for micro-components was developed to circumvent the issue of handling of small micro-parts while keeping in mind the need for high manufacturing through-put. The mechanical properties and microstructure of the material have been found to play a significant role in the forming of micro-components. In this work, the effect of mechanical property on the forming of copper micro-pins by the progressive forming process is highlighted. Empirical results show that the forming load decreases for forming micro-pin with 0.3mm diameter after annealing but the pin height obtainable decreases as well compared to that prior to the heat treatment.
Sub Micron Poly-Dimethyl Siloxane (PDMS) Replication Using Proton Beam Fabricated Nickel Moulds
Authors: Shao Pei Ge , van Kan Jeroen A. , Watt Frank
Published: September 2010

We present a process to fabricate Ni moulds on proton beam written (PBW) PMMA structures. These Ni mould are use to replicate PDMS lab on a chip devices featuring 300 nm details of high verticality, smooth sidewalls and high aspect ratios. The lifespan of the Ni mould can be extended and the functionality improved by means of introducing a 5 nm thick Teflon AF release layer. Following this method, PDMS chips have been fabricated for microfluidic experiments.
Ultra Precision Machining of Non-Ferrous Metals and Nitrocarburized Tool Steel
Authors: Osmer Jen , Meier A. , Gläbe R. , Riemer O. , Brinksmeier E.
Published: September 2010

This paper presents results for the machining of materials typically applied in ultra precision machining in comparison to a nitrocarburized tool steel. Analyzing and evaluating the machining results regarding surface integrity lead to recommendations for the ultra precision machining of this new mold material. The influence of feed, depth of cut and cutting speed on surface quality, resulting cutting forces and tool wear have been investigated. The results show that the decisive factor for the ultra precision machining of nitrocarburized tool steel are the significantly higher cutting forces. In some cases the high cutting forces lead to vibrations during the turning process deteriorating the surface integrity. Therefore, tool nose radius and depth of cut have to be reduced to minimize the cutting forces and avoid the vibrations.
Piezo Actuator and its Hysteresis Compensation for an Active Clamping System in Wood Machining
Authors: Hoffmeister Hans Werner , Loeis Kingliana , Schuller Bernd Christian
Published: September 2010

The modeling and compensation of hysteresis in piezoelectrically driven systems are very important for positioning and noise and vibration reduction applications. An active vacuum clamping system for a stationary wood machining center with piezo actuators for the purpose of vibration control has been developed. This active system is intended to reduce workpiece vibrations, which are excited during machining. However, the piezo actuators have an inherent hysteresis effect between input voltage and output position of the vacuum plate. The Bouc-Wen and the Classical Preisach methods are studied in this paper to model the hysteresis curves and to compensate the hysteresis effect of the integrated piezo actuator.
Automatic Surface Characterization for Micro-Structured Surfaces Fabricated by Fast Tool Servo Diamond Turning
Authors: Yu De Ping , Wong Yoke San , Hong Geok Soon
Published: September 2010

Fast tool servo diamond turning is a promising machining method for precision and complex micro-structured surfaces with spatial wavelength above tens of microns. It is crucial to measure and characterize the micro-structured surfaces to sub-micrometer form accuracy. The general purpose measurement instruments are not able to evaluate the true form accuracy between the measured surface and designed surface. Therefore, in this paper an automatic surface characterization method is proposed to evaluate the form accuracy for micro-structured surfaces. The fabricated surfaces can be measured by any high-resolution measurement instruments. After the surface measurement, an iterative closest point (ICP) algorithm is modified to align the measured surfaces to the designed surfaces with the form error evenly distributed over the whole surface. After alignment, the designed surface height corresponding to each measured point is calculated to form the areal error map. 3D surface parameters are chosen and calculated from the error map to characterize the surface form error. Experimental results demonstrate the effectiveness of the proposed surface characterization method.
Deformation Mode Construction Using Photoresist Microstructure Devices Produced with Nanoindention Technology
Authors: Weng Yung Jin , Weng Yung Chun , Liu Hsu Kang , Chiu Lin Hsiung
Published: September 2010

In this study, we try to produce SU-8 photoresist microstructure devices using
nano-imprint technology, and try to conduct nano-indention tests on SU-8 photoresist with
nano-indention detector, in order to describe the behaviors and characteristics of nano-indentions on
SU-8 microstructure devices and establish the deformation mode for the indention under
nano-meter level. The tests tell us that, after nano-indention tests, the result indention hardness
increases with the loading rate, indention repeats, and reduction of load or depth. Similarly, the
indention hardness decreases because of reduction of loading rate, extension of loading time, and
increase of load, and depth. Finally, we propose a deformation mode for nano-indention. This mode
can also be used to explain the deformation behavior of SU-8 under nano-indention.
Measurement of Spindle Thermal Growth on a Machine Intended for Micro/Meso Scale Milling
Authors: Saedon J.B. , Soo Sein Leung , Aspinwall David K.
Published: September 2010

Micro milling is gaining ground as the preferred process for the manufacture of micro/meso-scale components in conventional workpiece materials, in particular for miniature moulds and tooling inserts (~ 60HRC), for the plastics injection moulding industry. Following a brief literature review on microscale milling and associated machine tool/tooling developments, experimental results are presented in relation to spindle thermal growth for a compensated/cooled spindle operating at up to 60,000 rpm, designed to accommodate the machining of meso-scale/micro-scale components. The work involved investigation of spindle warm up and cool down rates for speeds ranging from 30,000 - 60,000 rpm and subsequently the evaluation of spindle growth using both non-contact and contact measuring systems. Growth levels of up to 16µm were detected despite active spindle cooling and the incorporation of a standard compensation algorithm within the control system. Modification to spindle acceleration and deceleration rates reduced error levels by up to 50%.
Design Models of Polymer Electrolyte Membrane Fuel Cell System
Authors: Mulyazmi  , Wan Daud Wan Ramli , Majlan Edy Herianto
Published: September 2010

One important aspect to develop fuel cell design is to use the concept of computational models. Mathematical modeling can be used to help research complex, estimates the optimal performance of fuel cells stack, compare several different processes, save costs and time in the investigation. This paper focuses on several reviews of research models to develop the system design of the Proton Exchange Membrane Fuel Cell (PEMFC). Purposes of this study are to determine the factors that affect system performance include: stack of PEMFC system, water management system and Supply of reactants to the PEMFC stack.
Quality Control Method Based on Gear Tooth Contact Evaluation Using Near-Infrared Ray Imagery
Authors: Nagata Masaki , Hirogaki Toshiki , Aoyama Eiichi , Iida Takahiro , Uenishi Yasuhiro , Matsubara Masami , Usui Yoshitaka
Published: September 2010

Conventionally, tooth contact evaluation has been performed visually by machine operators in gear manufacturing fields when finishing a gear or during assembly. With automation, the contact area’s boundary is unclear due to scattered light when visible light is used to obtain an image for tooth contact evaluation. We therefore focused on using near-infrared to prevent scattered light. First, we confirmed that the tooth contact image obtained by image binarization is hardly affected by the image threshold. Second, we propose a new method to extract the boundary part of the tooth contact by differential calculation of the fine near-infrared image. These methods allow automatic division of near-infrared images into the contact area, the boundary, and the non-contact area. Finally, the obtained result is compared with the tooth contact calculated from the measured tooth surface. We demonstrated that the near-infrared image method is effective for automatic tooth contact evaluation.
A Novel High-Resolution Optical Displacement Encoder Design Based on Double-Concave Lens
Authors: Fan Yi Hua , Lee Ying Tsun , Chen Chun Yu , Liao Yi Lin , Chen Ching En
Published: September 2010

A novel optical displacement encoder was proposed in this paper. An optical mechanism was designed by the equations of thick lens to change and modify the paths of light, and then to get a more visible position change in the optical detector to improve the measurement accuracy. The simulation results indicated that the optical mechanism with 5 mm stroke, which the lens radii of curvature of the incident and the exit surface on the lens were -0.625 cm and 1.25 cm, respectively, and the magnification was 50 times in imaging distance of 38 cm, could make the 1 nm movement intervals of light source to be about 50 nm movement intervals in the detecting surface. Thus we can combine the optical mechanism and a photo-detector array with 50 nm resolution and 25 cm total detecting length to form the optical displacement encoder with 1 nm measuring accuracy.
Video-Based Interferogram Analysis for Measuring Influence of Vibration to White Light Interferometry
Authors: Chong Wee Keat , Li Xiang , Wijesoma Sardha
Published: September 2010

In this paper, we present a video-based interferogram analysis method for measuring the influence of vibration on white light interferometer in terms of undesired change in optical path difference between reference and sample arms. The measurement principle is based on the analysis of interferograms which involves tracking and converting change in interferograms to physical change in optical path difference. The method proposed uses the original sensor in interferometer for data acquisition as such no additional hardware is required. Such an approach ensures that the properties of interferometer such as the bandwidth of sensor are considered and the vibration pattern recorded is close to the effective influence of vibration. With our method, the influence of vibration on white light interferometer and the performance of vibration isolation system can be objectively quantified and measured.
Molecular Interactions in PA6, LCP and their Blend Incorporated with Functionalized Carbon Nanotubes
Authors: Cheng Henry Kuo Feng , Sahoo Nanda Gopal , Li Lin , Chan Siew Hwa , Zhao Jian Hong
Published: September 2010

Multi-walled carbon nanotubes (MWCNTs) were functionalized with a carboxyl group (-COOH) to improve their dispersion in a nylon6 (PA6) matrix, a liquid crystal polymer (LCP) and their blend. This functionalized MWCNTs also achieved better interfacial adhesions with both polymer matrices and with both phases in the blend. The dispersion of MWCNT-COOH in the polymer matrices and their interfacial interactions with polymer molecules were found to be the most important factors affecting the properties of composites. Moreover, studies on morphological, rheological, and mechanical properties confirmed that a better miscibility between PA6 and LCP had been constituted in the presence of MWCNT-COOH. Therefore, it is observed that the functionalized MWCNTs not only played the traditional role as reinforcing fillers in the polymer matrices, but also performed a novel role as compatibilizers for their blend.
Atomic-Scale Planarization of Single Crystal Diamond Substrates by Ultraviolet Rays Assisted Machining
Authors: Touge Mutsumi , Anan Satoru , Wada Shogo , Kubota Akihisa , Nakanishi Yoshitaka , Watanabe Junji
Published: September 2010

The ultra-precision polishing assisted by the ultraviolet rays irradiation was performed to achieve the atomic-scale planarization of the single crystal diamond substrates. This polishing method is a novel and simple polishing method characterizing by a quartz disk and an ultraviolet irradiation device. The principle three crystal planes of the diamond substrate were polished by this method. The polished surfaces were evaluated by an optical interferometric profilers (Wyko), an atom force microscope (AFM) and LEED (low-energy electron diffraction). The surface roughness of the polished diamond substrates was evaluated as 0.2 ~ 0.4 nmRa in (100), (110) and (111) crystal planes. The LEED (low-energy electron diffraction) patterns indicated the almost perfect crystallographic structure without the residual processed strain beneath the polished surface. In this paper, the optimum polishing condition to achieve the atomic-scale planarization of the diamond substrates has been investigated by the evaluation of LEED patterns, Wyko and AFM images. The mechanismof the ultraviolet rays assisted polishing is discussed in detail.
Surface Micro-Structuring Using Polymer Elongation
Authors: Kaneko Arata , Kobayashi Hayato , Moronuki Nobuyuki
Published: September 2010

High-aspect structures are fabricated by photo-polymer elongation using a template. The template, tungsten wire of sub-mm diameter, makes SU-8 film locally stretched and deformed in long and fine fibrous geometry. The aspect ratio of fabricated structure becomes over 8, while the finest diameter is less than 10μm. Both of surface tension and viscosity of SU-8 film determines the yield of fibrous micro-structure. The wire diameter and drawing distance allow one to obtain desired profile of structure. Fibrous structures can be hexagonally aligned utilizing appropriate template with specific diameter and pitch of wire designed based on an analysis of surface energy.
Safe and Comfort Design of Micro-Structured Surfaces for Artifacts in Contact with Human
Authors: Moronuki Nobuyuki , Kaneko Arata
Published: September 2010

This paper discusses a design of micro-structure on the surface in contact with human from the standpoint of frictional property and feeling. Coefficient of friction on a floor varies with sliding speed in wet environment. At some condition where hydrodynamic pressure becomes dominant, the coefficient decreases and causes slip. Experiments were carried out on a special setup and structural design to decrease this pressure was discussed. It was found that structures of sub-millimeter pitch are effective in floor design. Then, the surface structure for handles was discussed. In this case, feeling becomes important rather than the change in sliding speed condition. It was found that sub-millimeter sized structure can improve the feeling while keeping high coefficient of friction under wet condition.
Flexible Transparent Conducting Film by Hot Embossing
Authors: Suparerk Aukkaravittayapun , Kerk Wai Tat , Wu Hu , Lu Hai Jing
Published: September 2010

Flexible transparent conducting (TC) film is a key element as the transparent electrode of the flexible electronics such as touch screen, solar cell, display or lighting. Current commercial flexible sputtered ITO films have shown some limitations; high sheet resistance (> 10 ohm/sq), deterioration of ITO film during repeatedly bending, indium scarce, and expensive fabrication process (sputtering). In this report, a new simple and cheap process to make such flexible TC film by using hot embossing and forming micro metal mesh underneath transparent conducting layer is proposed. This simple process has yielded a promising result with sheet resistance as low as 4 ohm/sq and the light transmission of 68% (@550nm). Future improvement on light transmission is discussed.
Chemical Surface Treatment for Enhanced Bonding Strength between Polymer Coating and Aluminum Alloy
Authors: Wu Linda Y.L. , Feng Y.Y. , Qi G.J.
Published: September 2010

Polymer materials are sometimes molded to aluminum alloy to form integrated industrial parts for special applications, such as high strength, heavy duty applications. To ensure the bonding strength for long term applications, chemical treatment of aluminum surface is a quick and efficient method prior to polymer injection molding onto aluminum part. In this study, chemical etching and anodizing processes were studied to obtain suitable surface roughness and porous structures to enhance the penetration of polymer into the pores leading to interfacial anchoring and high bonding strength. Surface roughness, surface contact angles, and surface porous structures were investigated by surface Profilometer, contact angle tester, and scanning electron microscopy. Bending tests and cracking analyses were carried out to determine the bonding strength. Optimized chemical treatment recipe and process parameters were established. Preferred surface characteristics are defined. The failure mechanism of bending test was analysed and correlated to the bending fracture phenomina.
Thermal Stablility and Oxidation Resistance of CrAlSiN Nano-Structured Coatings Deposited by Lateral Rotating Cathode Arc
Authors: Cheong Jhun Yew , Ding Xing Zhao , Tay Beng Kang , Zeng Xian Ting
Published: September 2010

In this paper, CrAlSiN coatings are deposited by a lateral rotating cathode arc technique. The high temperature oxidation behaviors of these coatings are studied in ambient atmosphere at temperatures ranging from 800°C-1000°C for an hour. The ternary TiAlN coating is used as the benchmark in this study. The surface morphology and chemical composition of the coating samples before and after oxidation at different temperatures are analyzed by scanning electron microscopy (SEM) equipped by energy dispersive X-ray spectrometer (EDX), glow discharge optical spectrometry (GDOS) and X-ray diffraction (XRD). The CrAlSiN coatings show much better oxidation resistance than the TiAlN coatings. TiAlN starts to oxidize from 800oC and forms a complete surface oxide layer after oxidation at 1000oC for an hour. However, CrAlSiN shows a relatively good oxidation resistance below 1000oC and only is oxidized to form a thin oxide scale with a thickness of 0.3 µm at 1000oC for one hour. It is found that the oxidation of both coatings is triggered from the surface metallic droplets generated by the arc deposition process.
Biodegradable Microfluidic Device: Hydrolysis, Decomposition and Surface Modification
Authors: Low Jia En , Koh Wei Xiang , Lai Joon Kit , Lee Yan Jie , Li Xu , Chen Ge , Juay Yang Kay , Zhao Jian Hong
Published: September 2010

Poly(lactic acid) (PLA) is a biodegradable and biocompatible aliphatic polyester whose lactic acid monomers are derived from renewable resources such as corn and sugar beet. As a thermal plastic it can be processed through compounding and injection. As such, we have developed a microfludic device using PLA aimed at blood dialysis application. To quantify the degradation of PLA, its hydrolysis at different pH value was studied. To study the bioresorbable property of these fabricated devices, its decomposition was tested by morphology observation and weight change measurements after embedding in soil under simulated environmental conditions. Upon contact with a hydrophobic surface, platelets and prothrombin are always activated to attach to the surface, resulting in blood clot. This would block the blood flow through the dialysis channels in the microfluidic device. To improve the hydrophilicity, hence the blood compatibility, chemical grafting of a hydrophilic polymer, poly(ethylene oxide) methacrylate (PEGmA), onto the surface of PLA microfluidic device was carried out and the changes in hydrophilicity was monitored through measuring the water contact angle. Our results indicate that chemical grafting of PEGmA significantly improves the hydrophilicity of the device surface.
Multi-Axis Control Ultraprecision Micromilling
Authors: Takeuchi Yoshimi
Published: September 2010

In recent years, ultraprecision micromachining technology draws wide attention. In particular, multi-axis control ultraprecision machine tools are playing an important role in producing complicated microparts made of a variety of materials. In addition, CAM software is also an essential element to control these machine tools. The paper deals not only with the current state of multi-axis control ultraprecision machine tools but also with the manufacture of two workpieces consisting of complicated shapes by means of micromilling.
A Feasibility Study on Laser-Mechanical Drilling of SiC Ceramics
Authors: Nath Chandra , Ng Gary Ka Lai , Lim Gnian Cher , Ko Jeong Hoon
Published: September 2010

Structural SiC (α-type) is believed to be widely applied in hostile environments such as high-temperature, high-corrosive applications in the semiconductor industries due to its superior thermo-physical and mechanical properties. However, the extremely high hardness and brittleness of SiC makes hole drilling difficult by the conventional mechanical drilling (CMD) technique. Laser can be used to drill SiC; but the resultant holes are often tapered and uneven, with tendency for microcracks and thermal damage to occur at the hole entry due to the high thermal shock from the laser. This paper reports on the experimental results of a sequential laser-mechanical drilling (LMD) technique for drilling α-SiC. At first, an Nd:YAG laser was used to drill a series of pilot holes on a 3 mm thick SiC plate. Then a diamond-coated carbide drill was sequentially applied to these holes to obtain desired hole diameter of 0.5 mm. A number of through holes on SiC (aspect ratio: 6) were successfully obtained using this approach. The quality of the drilled holes were assessed in terms of the entrance and exit sizes and conditions, hole taper angle, hole edge shapes, and microcracks. Finally, comparisons of the LMD performances were also made against the holes predrilled by the laser itself and holes of the similar size drilled separately with the CMD technique. The experiment results show that the proposed drilling approach can effectively drill α-SiC ceramics.
Effect of Machining Parameters and MQL Liquids on Surface Integrity of High Speed Drilling Ti-6Al-4V
Authors: Rahim Erween Abdul , Sasahara Hiroyuki
Published: September 2010

Surface integrity is particularly important for the aerospace industry components in order to permit longer service life and maximized its reliability. This present work compares the performance of palm oil and synthetic ester on surface roughness, surface defect, microhardness and subsurface deformation when high speed drilling of Ti-6Al-4V under MQL condition. The drilling tests were conducted with AlTiN coated carbide tool. The surface roughness decreased with increasing in cutting speed and thicker subsurface deformation was formed underneath the machined surface. Grooves, cavities, pit holes, microcracks and material smearing were the dominant surface damages thus deteriorated the machined surface. For both lubricants, the machined surface experienced from thermal softening and work hardening effect thus gave a variation in microhardness values. The results indicated the substantial benefit of MQL by palm oil on surface integrity.
New Type MEDM Machine Tool and its Control Technology
Authors: Zhang Lian Xin , Ji Fang , Zhang Yong Bin , Tang Xiao Hui , He Jian Guo
Published: September 2010

Open architecture NC orienting MEDM application was studied and the “IPC + UMAC motion controller” architecture was presented. And then, the integration method and principle, that the motion system, WEDG (Wire Electrical Discharge Grinding) system, coolant system, visual supervising and measuring system, micro-energy pulse Generator with NC, were investigated. Based on the PComm32, control software with general NC machine tool HMI style, was developed and whole machine tool was integrated successfully. At last, a lot of experiments were carried out, and the results demonstrated that the MEDM machine tool has the capabilities of manufacturing micro- electrode, micro hole, complex 2D micro workpiece and milling 3D model.
Stationary Position for Hybrid Journal Bearing with Horizontal Point Injection Ports
Authors: Nossov V.R. , Gómez-Mancilla J.C. , Ramirez-Vargas I. , Rivera-Arreola D.E.
Published: September 2010

This paper deals with the modeling and identification of a stationary eccentricity and attitude angle for a short journal bearing with horizontal point injection port. In modeling we use the Dirac spatial delta function which allows to obtain a pressure field in a close analytical form. After using the pressure force components in the oil film, which is the addition of the Ocvirck force in the classic case and pressure force we obtain a non linear equations system with respect to stationary eccentricity and attitude angle. We found the solution equation system by obtaining the roots using the program MATHEMATICA 6 and by iteration. We developed and analyzed the work by both point pressurizing ports π/2 and 3π/2 in the journal bearing. The results are presented in tables that show the relation between eccentricity, attitude angle and the Sommerfeld´s number S.
The Boundary Element Method Applied to Visco-Plastic Analysis
Authors: Pineda E. , Aliabadi M.H. , Zapata Janis
Published: September 2010

This paper presents a new formulation of the Dual Boundary Element Method to visco-plastic problems in a two-dimensional analysis. Visco-plastic stresses and strains around the crack tip are obtained until the visco-plastic strain rate reaches the steady state condition. A perfect visco-plastic analysis is also carried out in linear strain hardening (H’=0) materials. Part of the domain, the part that is susceptible to yield is discretized into quadratic, quadrilateral continuous cells. The loads are used to demonstrate time effects in the analysis carried out. Numerical results are compared with solution obtained from the Finite Element Method (FEM).
Material Characterization for Dynamic Simulation of Non-Homogeneous Structural Members
Authors: Quintana-Rodríguez J.A. , Doyle J.F. , Carrión-Viramontes F.J. , Samayoa-Ochoa Didier , López-López J. Alfredo
Published: September 2010

Generally, simulation of non-homogeneous materials requires a homogeneous representation with equivalent properties different from the constitutive elements. Determination of the equivalent properties for dynamic simulation is not always a direct and straightforward calculation, as they have to represent, not only the static reactions, but also the dynamic behavior, which depends on a more complex relation of the geometrical (area, inertia moment), mechanical (elastic modulus) and physical (density) properties. In this context, the Direct Sensitivity Method (DSM) is developed to calibrate structural parameters of a finite element model using a priori information with an inverse parameter identification scheme, where parameters are optimized through an error sensitivity function using experimental data with the dynamic responses of the model. Results demonstrate that parameters of materials can be calibrated efficiently from the DSM and that key aspects for this calibration are noise, sensitivity (structural and sensor), and the finite element model representation.
Surface Stress Concentration Analysis of Shot Peened Aluminium Alloys
Authors: Solis-Romero J. , Oseguera-Peña J. , Verduzco-Martínez J. , González-Sánchez J.
Published: September 2010

Fatigue limit for surface crack initiation on shot peened Aluminium Alloys resulted to be determined by surface residual stress and stress concentration, according to the magnitude of the applied stress. The effect of surface roughness considered as micro-notches (dents) has been analysed by using the Vallellano and Navarro’s formulation. It was also determined that the stress gradient associated to those dents dominates over the closure stress effect.
Alloying Effects on Wetting Ability of Diluted Ag-Based Melts on Ceramic Substrates
Authors: Weltsch Z. , Lovas A.
Published: September 2010

The wetting angles (Θ) of Ag-M based melts (M: Cd, Sn, Sb) on graphite and Al2O3 substrates are compared. Despite of the inert chemical character and the similar surface roughness of substrate materials, the wetting angle is smaller on the Al2O3. The compositional and concentration dependence of Θ exhibits similar trends, than that, observed in the bulk transport properties such as the specific electrical resistance or the thermopower obtained on the same alloys in solid state. No segregation effects can be detected on the solidified metal drops.
Aptitude for Cold Rolling of Laser Welded Joints and their Environment in the Case of Steel Sheets
Authors: Buza Gábor , Janovszky Dóra , Zupkó I. , Tomolya K. , Sveda M. , Naszrai T. , Puskás Cs. , Szabados O. , Kálazi Z.
Published: September 2010

In order to perform a continuous cold rolling of steel sheets, hot rolled coils need to be attached to each other in order to get an endless sheet. This process can be achieved by laser key-hole welding as well. The structure and mechanical properties (e.g. hardness) of the welded joint without added metal, as well its heat affected zone differs significantly from the base metal. During our laboratory experiments the aptitude of cold rolling of joints and their environment, as well as the change in the features of materials was analyzed. During the rolling phases the hardness of the joint is higher than the ground structure, the strip thickness is modified depending on the difference of the hardness during the passes. According to our findings, the significant difference in measured hardness profile and texture structure prior to cold rolling and during cold rolling is minimized due to a recrystallisation annealing treatment following the cold rolling procedure. It is obvious that the normalization before cold rolling has advantageous effect to the properties of the welded joint. Elongation of the normalized samples is bigger than elongation of the non normalized samples.
Evaluation of Cooling Characteristics of Quenchants by Using Inverse Heat Conduction Methods and Property Prediction
Authors: Felde Imre , Réti Tamás
Published: September 2010

A sequential numerical method for characterization of hardening performance of quenchants applied for steel quenching is outlined here. This novel method is based on the specific processing of measured time–temperature samples performed as a result of cooling curve tests. The heat transfer coefficient, as a function of surface temperature, characterises the heat transfer during cooling and is calculated using an iterative inverse algorithm. The heat transfer coefficient is used for calculation of the microstructural constituents and the hardness profile of cylindrical samples of arbitrary diameters. The hardening performance of the media is evaluated by the estimated hardness of the specimen obtained by heat treatment.
Effect of the Infiltration Pressure on the Properties of Composite Wires
Authors: Kientzl Imre , Dobránszky János , Németh Árpád
Published: September 2010

Nowadays the development of composite materials has increasing importance. In this study Nextel 440 type alumina fibre reinforced aluminium matrix composite wires were investi-gated. Composite wires produced using the continuous process are suitable to simplify the introduc-tion of fibre reinforcements into aluminium castings as well as the production of double composite, sandwich and preferentially reinforced structures. This paper focuses on the porosity of composite wires because minimizing porosity is the primary condition of good mechanical properties. Compo-site wires were produced with different infiltration pressures (0.83 MPa, 1.03 MPa, 1.24 MPa, 1.52 MPa, 1.65 MPa 1.86 MPa and 2.07 MPa) and different diameters (1 mm and 2 mm) to determine the correlation between infiltration pressure and the porosity of wires. 10 grinded cross-sectional samples were made from each type of composite wires. Based on the micrographs of these samples the volume fraction of aluminium was determined by image analysis, which also yielded informa-tion on the porosity of wires. The results show that there is direct linear correlation between the infiltration pressure and the change in porosity. These findings, however, are valid only for the in-vestigated range of pressure.
Mechanochemical Phenomena during Fine Comminution of Clay Minerals for Ceramic Bricks and Roof-Tiles
Authors: Gömze László A.
Published: September 2010

During the fine comminution of clay minerals and layered silicate materials with relative large volume of specific surface area appreciable changes in chemical and minerological compositions can be observed. In this paper is described the mechanochemical investigation of conventional clay minerals from „Lenti” region (Hungary), having natural BET specific surface larger than 35-40 square metres per grams. The laboratory experiments made by author had shown an intensive reduction of specific surface volume at the beginning of grinding, further relatively slow growth and reduction of BET and Langmuir surfaces were observed. The content of mineral Muscovite–2M1 – (K, NH4Na)Al2(SiAl)4O10(OH)2 – has decreased and the contents of Quartz – SiO2 – and Illite-1M (NR) – KO.7Al2(SiAl)4O10(OH)2 – have increased considerable depending on grinding time. Increasing the milling time the amount of Albite – NaAlO.91Si3O8 – and other mineral components were also not stable, but their content have varied not so strong as Muscovite–2M1 or Quartz and Illite–1M. The examined clay minerals had a certain proportion of amorphous particles as well, but in this contribution only the changes in proportions of crystalline particles are described.
Third Neighbor Analytic Tight-Binding Solutions for Electronic Structure of Carbon Nanosystems
Authors: László István
Published: September 2010

Third neighbor analytic tight-binding formulae were obtained for graphene sheets and
nanotubes. After fitting the corresponding of-diagonal matrix elements can be used in numerical
electronic structure calculations of nanotubes and corrugated graphene.
Nano-Micro Pigment Composites for High Performance Paints
Authors: Mara Mária , Csanády Ágnes , Tolnai Gyula , Németh Péter , Bertóti Imre , Sajó István E. , Papp Katalin , Hargitai Hajnalka
Published: September 2010

In this work, novel types of colored, organic and water based paints have been developed. These paints can be produced less expensively and have equivalent or better properties compared to existing paints in the market. These new paints use organic nanocrystalline dyes (about 10 nm in size), which produce the various colors by absorption. The results are achieved with pigment composites containing nano-Cu-phthalocyanine (CuPC) pigment crystallites and finely precipitated and ground micro Al(OH)3 distance-holder (“spacer”) disks.
Tribology Study of Silicon Nitride-Based Nanocomposites with Carbon Additions
Authors: Pfeifer Judit , Sáfrán György , Wéber Ferenc , Zsigmond Valéria , Koszor Orsolya , Arató Péter , Balázsi Csaba
Published: September 2010

Tribology tests were conducted on silicon nitride-based nanocomposites with various carbon additions to explore the effects of microstructure, the type and quantity of carbon additives and the preparation routes on the behavior. The nanocomposites consisted of Si3N4 and C in the proportions of 1 – 10 wt % carbon nanotube (CNT), or carbon black (CB), or graphite, or graphene. Specimens were produced by hot isostatic pressing. X-ray diffraction and scanning electron microscopy were used to reveal phase composition and microstructure. Unlubricated ball-on-disk tribology tests with silicon nitride counter face were carried out at room temperature in ambient atmosphere. Contact profilometer was used to profile the wear tracks. The friction coefficients of the pure Si3N4 and Si3N4 samples with 3% CNT varied between 0,77-0,81. Addition of 10% graphite and 3% CB to Si3N4 resulted in friction coefficients of 0,83 and 0,72 respectively. Si3N4 samples with 3% graphene showed distinctly lower friction levels of 0,52 and smaller scatter of the measured values. The wear track study revealed that high graphene content in the Si3N4 matrix caused relatively big wear particles and an uneven wear track.
Effect of Crucible Diameter and Wall Roughness on the Melt Flow Generated by Rotating Magnetic Field
Authors: Rónaföldi Arnold , Kovács Jenő , Roósz András
Published: September 2010

The effect of flow on the structure of solidified alloys can be investigated by the unidirectional solidification of alloys stirred with a magnetic (magnetohydrodynamics – MHD) method. This MHD method is a rotating magnetic field (RMF)-type. The paper deals with the melt flow generated by this RMF.
Production of Single Crystal Thermoelectric Bismuth Telluride Alloys
Authors: Vallasek Stefan I. , Veres Zsolt , Roósz András , Szőke János , Szirovicza Péter , Bárczy Pál
Published: September 2010

Thermoelectric (TE) semiconductor materials are widely used for miniaturized versatile cooling devices in a wide spectrum of equipments and energy generation in space vehicles. The bismuth telluride pseudobinary alloy family presents the best characteristics for room temperature TE cooling applications. Using appropriately oriented single crystals instead of the well known polycrystalline materials made by powder metallurgy methods, the efficiency of the TE device (Thermoelectric Cooler – TEC or Thermoelectric Generator – TEG) could be almost doubled. For having good quality TE material it is required to produce equally doped single crystals by the controlled crystallization process, namely with the Bridgman-Stockbarber method. Our experiments were made in the Universal Multizone Crystallizator Type UMC, developed by the ADMATIS Ltd., Miskolc, using a quartz tube under high vacuum conditions and automatically controlled thermal field parameters. The crystallographic analysis of the obtained samples was made by Scanning Electron Microscopy – (SEM), X Ray Diffraction – (XRD), and neutron diffraction (TOF spectrometry).
Effect of Texture on Hydrogen Permeability in Low Carbon Al-Killed Steels
Authors: Enikő-Réka Fábián , Szabó Péter János
Published: September 2010

The susceptibility to fish-scale formation of cold rolled Al-killed low carbon enamel grade steel sheets is mainly determined by the hydrogen permeability.
The role of the grain orientation in the hydrogen permeation time was investigated using scanning electron microscope based electron backscatter diffraction measurements. The fragmentations of massive cementite phase have a significant influence not only on the hydrogen permeability but also on the evolution of texture during the cold rolling process. Results showed that {111}[uvw] texture act as trapping site for hydrogen.
Grain Boundary Investigation of AISI 304 Type Steel Using EBSD
Authors: Gaál Zoltán , Szabó Péter János , Ginsztler János , Dévényi László
Published: September 2010

This paper deals with the investigation of grain boundary engineering processes in case of AISI 304 type austenitic stainless steel. The effects of the thermo-mechanical treatments for the modification of the grain boundary structure are demonstrated on the special grain boundaries. The proper thermo-mechanical treatments can increase the fraction of the CSL-boundaries. Since the CSL-boundaries are resistant against intergranular degradation processes, materials owning enhanced properties can be developed due to these treatments. The investigation of the grain boundary character distribution is carried out by automated electron back scattered diffraction (EBSD) measurements after different thermo-mechanical treatment processes. The effect of the heat treatment duration on the grain boundary structure is examined; the optimal treatment is represented. It is shown by experimental results, that the parameter settings of the evaluation method strongly influence the obtained results.
Nondestructive Inspection of Ductile Cast Iron by Measurement of Minor Magnetic Hysteresis Loops
Authors: Vértesy Gábor , Uchimoto Tetsuya , Takagi Toshiyuki , Tomáš Ivan
Published: September 2010

Systematic measurement of minor magnetic hysteresis loops of traditional hysteresis tests requires substantially lower magnetization of samples and offers higher sensitivity of detection of changes in the ferromagnetic materials’ microstructure. The keynote idea of this method, called Magnetic Adaptive Testing (MAT) is utilization of sensitive correlations between the varied microstructure of the magnetized material and the corresponding, highly sensitive modifications of some of the minor hysteresis loops. The paper presents some of the recent results of the MAT measurement performed on specially prepared series of cast iron samples. Results of the non-destructive magnetic tests were compared with the destructive mechanical measurements of Brinell hardness and linear correlation was found between them. A very good correlation was also found between magnetic descriptors and conductivity and chill/ferrite area fraction. Based on these results, Magnetic Adaptive Testing is suggested as a highly promising non-destructive method for monitoring structural changes in different types of ferromagnetic materials.
On Modeling of Portevin - Le Chatelier Effect
Authors: Béda Peter B.
Published: September 2010

There are several self-sustained oscillatory phenomena observed at plastic deformation of metals. One of them happens at the beginning of plastic behavior and leads to appearance of the famous Lüders-Hartmann bands. However, it can also be found self-sustained oscillations well beyond the yield stress like Portevin and Le Chatelier did in the early 20th century. This paper presents a simple model of that by using continuum approach and the theory of dynamical systems.
Approximation of the Temperature and Time Dependence of the Stress versus Rupture Life Curves by Power Functions
Authors: Dudás Zoltán
Published: September 2010

This paper explains and demonstrates an approximation method for the calculation of the stress values depending on the temperature and time, or time values depending on the stress and temperature using time dependent and temperature dependent power functions. The approximation is based on measured data and the paper shows the verification of the power function approximation.
On the Relation between the Matensite Start Stress and the Temperature in Single Crystalline Cu-11.5wt%Al-5.0wt%Ni Shape Memory Alloy
Authors: Elrasasi Tarek Y. , Daróczi L. , Beke Dezső L.
Published: September 2010

General form of the well known-relation between the critical stress, necessary to start/finish martensite/austenite formation, and the test temperature is simply and plausibly obtained from our local equilibrium model of phase transformation [1], and compared to the classical forms of the Clausius-Clapeyron relation. Although in general, first of all because of the stress and temperature dependence of the transformation strain, εtr, the above relations are not inevitably linear, in most of the cases linear functions were observed. Using the results of our experiments carried out on single crystalline Cu-11.5wt%Al-5.0wt%Ni samples for the strain stress hysteretic loops at constant temperatures [2], the slopes of these functions are analyzed on the basis of the relations obtained and it is shown that these are different due to different stress dependence of the elastic energy contributions.
Real-Time HIL Closed Loop System of Rolling Mill’s Electro-Hydraulic Gap Adjustment
Authors: Kővári Attila
Published: September 2010

Hardware-in-the-loop (HIL) test is a good ground for examine the dynamic model of
rolling to observe the movement of the mill and monitor dynamic behavior of the hydraulic system
and the mill. Nowadays hydraulic actuators/capsules are used to control the gap in rolling mills
which determines the strip thickness, profile and flatness. Using HIL simulation, dynamic
parameters of rolling mill stand and hydraulic gap adjustment system can be tested together in realtime.
It has possibility to examine the dynamic phenomena inside the mill stand and hydraulic
system using trials to test how system dynamic behavior changes when system’s parameters are
shifted. In this paper a HIL real-time model was developed and realized to test the dynamic behavior
of the complete rolling mill system which enables us to observe the system’s parameter variations
for example when seals are worn out in the hydraulic actuator.