bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of Fatigue Life by FEMFAT on the Weld Configuration of Spot Welding
Authors: Lim Bok Kyu , Kim Min Gun , Chung Ku Hyun , Kim Dong Youl , Choi Young Woo
Published: March 2009

The stability of plate structure is a very critical problem. The spot welding is practically
designed by experiential decisions; so, it is inefficient and risks fatigue fracture. In real structure,
multi-spot welded joints are more frequently used than single-spot welded joint. The fatigue
behavior of multi-spot welded joints is different from that of single-spot welded joints. The fatigue
lives of spot-welding specimen and multi points spot-welding structure are predicted using a
FEMFAT 4.4e based on the linear finite element analysis. It is necessary to establish a reasonable
and systematic design criterion for the long life design of the spot-welding body structure. In this
study, relative location of spot welding was chosen as parameter and the stress distribution around
the spot-welding joints’ subjected tensile load was numerically analyzed.
Laser Epitaxial Cladding of Ni-Base Single Crystal Superalloy
Authors: Fujita Yoshihiro , Saida Kazuyoshi , Nishimoto Kazutoshi
Published: March 2009

Microstructure and crystallographic orientation in the overlay weld metal have been
investigated using Ni-base single crystal superalloy CMSX-4. Laser power, laser scanning speed
and wire feeding speed were varied. The microstructure and crystal orientation were analyzed by
microscopy and electron backscattered diffraction pattern. Microstructural observation revealed
that the overlay weld metal grew epitaxially on the substrate and stray crystal tended to be formed
at the conditions of high power and high Vf/Vw (Vf: Wire feeding speed, Vw: Laser scanning speed).
In addition, solidification morphology, dendrite growth direction and single-crystallized condition
were evaluated by combining solidification model to heat conduction model. These predicted
results agreed qualitatively with the experimental ones. Based on the above results, the singlecrystallized
cladding with ten passes could be achieved.
Magnetocaloric Properties and Magnetic Anisotropy by Tailoring Phase Transitions in NiMnGa Alloys
Authors: Albertini Franca , Solzi Massimo , Paoluzi Antonio , Righi Lara
Published: March 2009

The giant magnetocaloric properties of NiMnGa alloys can be enhanced by suitable composition
changes that make structural and magnetic transition temperatures to coincide. In this paper we
report results on critical temperatures, magnetic anisotropy, and magnetocaloric effect in Ni- and
Mn-rich alloys as a function of composition. A phenomenological phase diagram, useful for the
identification by thermomagnetic analysis of magnetic and structural transitions in the vicinity of
their coincidence, is proposed. Particular emphasis is given to the discussion of giant
magnetocaloric effect of those alloys showing a first order magnetostructural transition, the method
of its determination, and the potentialities for applications in the field of magnetic refrigeration.
Dynamic Material Properties of Stainless Steel and Multiphase High Strength Steels
Authors: Durães M. , Peixinho Nuno
Published: March 2009

This work presents results of tensile testing of H400 stainless steel, DP600 and TRIP600
at different strain rates. Mechanical properties were determined from tensile test using flat sheet
specimens and recurring to different test techniques: servo-hydraulic machine and a tensile-loading
Hopkinson bar. The test results were used to compare different mechanical properties of the tested
steels and to validate constitutive equations intended to provide a mathematical description of strain
rate dependence, namely the Cowper-Symonds equation. Following previous research work in
dynamic material proprieties of multiphase and stainless steel grades, the energy absorption in
quasi-static crushing of thin walled section made of the tested materials was subsequently
investigated. Crush tests were performed in top-hat and hexagonal section tubes manufactured using
laser welding. The experimental results were compared in order to assess the efficiency of the
different steel grades for energy absorption.
Hydrogen Storage in Nanocrystalline Mg Powders
Authors: Révész Ádám
Published: March 2009

Conventional polycrystalline MgH2 was ball-milled under hydrogen atmosphere
Afterwards 2 mol % pre-milled Nb2O5 (∼ 40 nm) was added to the MgH2 as a catalyst and the
milling was continued. The effect of the milling duration and microstructure on the temperature of
hydrogen desorption and on the dehydriding kinetics of the ball-milled MgH2 + Nb2O5 powders was
analyzed. In addition, taking into account the microstructural parameters, e.g. the median and
variance of the log-normal grain-size distribution of MgH2 powders, the reaction kinetics can be
modeled by introducing a multi-particle reaction function.
Mechanical and Electrical Testing of Electrically Conductive Silicone Rubber
Authors: Valenta László , Bojtos Attila
Published: March 2009

Silicone rubber is an essential construction material in food industry, medicine and in
some fields of mechanical engineering, because it has good mechanical, electrical, biological and
other special properties. One needs to know these material properties in order to develop silicone
sensors. We performed several standard measurements for rubber, like tensile strength, cyclic
tensile, bending, fatiguing, stress relaxation tests etc. To investigate the electrical properties, we
measured the resistance of silicone during the mechanical tests. The paper summarizes the newest
results of our research in connection with mechanical and electrical properties of conductive
silicone rubber.
Testing and Modeling the Tensile Strength Behavior of Glass Fibers, Fiber Bundles and Fiber Mat
Authors: Molnár Kolos , Gombos Zoltán , Vas László Mihály
Published: March 2009

In this paper glass fibers, chopped roving pieces, and fiber mats were tested in case of
emulsion bonded glass fiber mat samples. Relationships between the tensile strength properties of
the different structural levels of the fiber mats were studied and fiber bundles as structural elements
of fiber mats were modeled by idealized statistical fiber bundles developed by the Department of
Polymer Engineering, BUTE. The geometrical and mechanical measurements were carried out by
image processing methods and a computer aided tensile tester. The results proved that the modeling
method gave a tool in understanding the failure behavior of the fiber mat samples and studying the
effect of the structural parameters. The applicability of the modeling method is demonstrated by the
good agreement with some measurements.
Preparation of MWCNT/Carbon Fabric Reinforced Hybrid Nanocomposite and Examination of its Mechanical Properties
Authors: Romhány Gábor , Szebényi Gábor
Published: March 2009

In our work we have prepared carbon fiber/epoxy composite and carbon fiber/carbon
nanotube/epoxy hybrid nanocomposite laminates by hand laminating assisted by vacuumbag
technology. During the production of the specimens we have encountered the viscosity increasing
effect of nanotube filling, which we characterized by a viscosity test. The results of the test showed,
that in the lowest shear rate range carbon nanotube filling can cause an increase of viscosity by
three orders of magnitude, but also at higher shear rates the viscosity of the nanotube filled epoxy
resin was ten times the viscosity of the unfilled resin. Mechanical properties of the composite and
hybrid composite have been compared by tensile, bending and interlaminar shear tests. During the
tensile tests AE signals have also been recorded. The fracture surfaces have been examined by SEM
micrographs. The nanotube filling has decreased the tensile strength and the modulus of elasticity
by 7-8 percent presumably indirectly, the bending properties didn’t change noticeably, but the
interlaminar shear strength of the composite has increased by 15 percent thanks to nanotube filling
of the matrix. The decrease of the delamination inclination of the hybrid composite has been
affirmed both by the AE and SEM results.
Equations and Verification of New Diffusion Parameters
Authors: Dudás Zoltán
Published: March 2009

This document shows the equations and some calculation results of two new Diffusion
parameters. The Diffusion parameters assist the calculation of different temperature or time values
for equivalent diffusion processes. The Diffusion parameters include temperature dependent and
temperature independent factors. The document shows that the introduced Diffusion parameter is
suitable for the accurate calculations of the temperature and time values for equal simple diffusion
processes. The document shows, that the frequently used Larson-Miller parameter (LMP) does not
give accurate results if we use the temperature and time values of equal simple diffusion equations
for the LMP calculations.
Some Problems in Modelling of the Fast Deformation of Metals
Authors: Pálmai Zoltán
Published: March 2009

We have developed a technological and mathematical model for the fast deformation of
metals, which, as a result of the non-linear nature of the process, is equally suitable for the
description of stable (continuous or periodic) and also chaotic states. In the case of stable solutions,
the various numerical methods generally give consistent results, but in chaotic cases significant
differences can be observed in the space of state characteristics, especially within the range
determined by the strange attractor.
Environmentally Acceptable Pre-Treatment of Zinc with Alkyl Diphosphonates for Corrosion Protection
Authors: Pilbáth A. , Pfeifer É. , Kármán F.H. , Felhősi Ilona , Mink J. , Kálmán Erika
Published: March 2009

The objective of our studies was to investigate the layer formation of 1, 5-diphosphonopentane
(DPP) on zinc surface from aqueous solution. For surface treatment, water based solutions
of 1, 5-diphosphono-pentane was applied with different treatment times. Evidence of the adsorption
of the diphosphonic acid on the zinc surface was obtained using the Infrared Reflection Absorption
Spectroscopy (IRRAS).
Preparation of Si3N4 Composites with Single Wall Carbon Nanotube and Exfoliated Graphite
Authors: Koszor Orsolya , Wéber Ferenc , Vértesy Zófia , Horváth Zsolt E. , Kónya Zoltán , Biró László Péter , Kiricsi Imre , Arató Péter , Balázsi Csaba
Published: March 2009

Silicon nitride based composites with 3wt% of single wall carbon nanotubes and
exfoliated graphite have been prepared. Optimisation of the manufacturing processes has been
conducted to preserve the carbon nanotubes and exfoliated graphite in composites and to avoid
damaging during high temperature processing. The first results show that carbon nanotubes and
exfoliated graphite have a good contact to the surface of silicon nitride grains. In the case of
increase of sintering pressure an increase of bending strength was achieved. It was found that
microstructure features achieved by properly designed sintering parameters are the main responsible
factors for the strength improvements.
Paintability of Traditional and Chromium(VI)-Free Conversion Layers on Galvanized Steels
Authors: Kőszegi Szilvia , Dénes Éva
Published: March 2009

Continuous hot dip galvanized steel samples have been treated with traditional
chromium(VI)-containing passivator and environment friendly rare-earth metal containing ceriumsalt
and lanthanum-salt based solutions using different immersion times. The treated surfaces have
been examined by scanning electron microscope equipped with an energy dispersive X-ray analyser.
After the pre-treatment the samples have been spray-painted with epoxy-based organic paint. The
adhesion was tested with bending and cross-cut test. Thereafter salt spray test was performed on
duplex systems. After 48 hours samples have been taken out from the corrosion chamber in order to
perform electrochemical impedance measurements for 24 hours. Based on the results the most
promising passivation among the chromium(VI)-free solutions has been found to be the cerium-salt
based treatment. The adhesion of the organic coating was better on cerium-chloride treated substrate
than on chromated one, while the anti corrosion properties of the two duplex systems were
comparable.
Developments in the Field of Rapid Prototype Production
Authors: Kovács Norbert Krisztián , Kovács József Gábor
Published: March 2009

Characteristics of 3D printed specimens are porous structure and low mechanical
strength. Due to porous structure post treatment is possible, and in most cases infiltration with an
epoxy resin, wax or cyanoacrylate material takes place. As a result of post treatment, the
mechanical strength can be increased by 100%, although this is strongly influenced by the
infiltration depth that depends on the porous structure and the resin viscosity. In the framework of
the common research of the Department of Polymer Engineering, BME and Varinex Zrt. the
applicability of a 3D printer is examined in the field of direct tool making. As the first step, the
resin uptake ability of specimens prepared with a Z810 3D printer is examined.
ATIG Welding of Duplex Steel
Authors: Sándor Tamás
Published: March 2009

The ATIG welding which is the high productivity version of conventional TIG welding,
parallel with productivity increasing has some advantageous effect both on HAZ and weld joint
grain structure. In this paper the effect of ATIG welding on austenite/ferrite ratio in duplex steel
will be represented with experimental results performed on 8 mm thick 2205 type duplex steel. As
collateral benefit through these results new evidences are originated to prove the “reversed
Marangoni effect” theory.
The Optimization of Heating the Billets in the Mills
Authors: Tóth János
Published: March 2009

The heating of basic material is considered the first step of the plastic hot forming. Most
of the „prescriptions” concerning this process are based on practical data and basically they can be
limited to the checking of the surface temperature of the billet. The model described in this paper
makes it possible to determine the temperature distribution developing inside the billet while the
system of the conditions of warm-up can be planned and optimized as a function of the physical
parameters of the heated material.
Milling and Consolidation by Hot Rolling of Al-Fe-Cr Alloy
Authors: Rodrigues C.A.D. , Tremiliosi-Filho G. , Rollo J.M.D.A. , Yavari Alain Reza , Kiminami Claudio Shyinti , Botta Filho Walter José
Published: March 2009

This paper discusses the preparation of partially amorphous Al90Fe5Cr5 and Al90Fe7Cr3
powder alloys by mechanical milling and their subsequent consolidation by hot milling. Samples
milled for 60 hours showed a microstructure composed of amorphous phase and nanocrystalline Al.
The heat treatment of these powders resulted in the equilibrium phases: fcc-Al + (Al3Fe and Al5Cr
intermetallic phases). Hot rolling these powders at 430°C resulted in consolidated samples with a
fine microstructure composed of Al, Al3Fe and Al5Cr intermetallic phases and high porosity. The
high hardness values of about 417HV of the intermetallic compounds formed during the rolling
process presented the main obstacle to obtaining totally homogenous and consolidated samples.
A Comparison between CoNiCrAlY Bond Coat and Zirconia Plasma Sprayed Coatings on Creep Tests
Authors: Reis Danieli A.P. , de Moura Neto Carlos , Couto Antônio Augusto , Silva Cosme Roberto Moreira , Neto Francisco Piorino , Barboza M.J.R.
Published: March 2009

Thermomechanical and electrical properties of zirconia-based ceramics have led to
a wide range of advanced and engineering ceramic applications like solid electrolyte in
oxygen sensors, fuel cells and furnace elements and its low thermal conductivity has allowed
its use for thermal barrier coatings for aerospace engine components. A comparison
between CoNiCrAlY bond coat and zirconia plasma sprayed coatings on creep tests of the
Ti-6Al-4V alloy was studied. The material used was commercial Ti-6Al-4V alloy. Yttria (8
wt.%) stabilized zirconia (YSZ) with a CoNiCrAlY bond coat was atmospherically plasma
sprayed on Ti-6Al-4V substrates by Sulzer Metco Type 9 MB. Constant load creep tests were
conducted on a standard creep machine in air on coated samples, at stress levels of 520
MPa at 500°C to evaluate the oxidation protection on creep of the Ti-6Al-4V alloy. Results
indicate that the creep resistance of the ceramic coating was greater than metallic coating.
New Method of Controlling the Carbon Content of High Chromium Alloyed Powders during High Temperature Sintering
Authors: Ahonen Sami , Laumen Christoph , Wiberg Sören
Published: March 2009

Atmosphere control in a continuous sintering furnace is one of the most important
variables in a successful sintering process. This statement becomes even more weight when
sintering of high chromium containing powders at elevated temperatures is applied. Depending on
the sintering atmosphere, de-carburization at the surface of a product is almost impossible to avoid.
The production of more highly loaded PM parts by sintering requires higher sintering temperatures,
which in turn increases the need for controlling the carbon level, and limiting surface decarburization.
One way to control the carbon level is to add CO to the sintering atmosphere and increase the
carbon activity of the atmosphere. This idea has been used in conventional carburizing for decades.
But is it applicable for sintering processes at temperatures up to 1250°C? The presented paper
shows results of tests on Astaloy CrM bodies with additions of up to 0.6% carbon that were sintered
at 1250°C in carbon monoxide containing atmospheres with and without hydrogen additions.
Finally, an outlook of how this technology could be implemented in industrial scale sintering
furnaces will be given.
The Study of the Particles Size Influence on the Venturi Scrubbers Perfomance
Authors: Damasceno João Jorge Ribeiro , Gama M.S.C. , Silva N.C.
Published: March 2009

The suspended particles in the air are a factor that causes chronic illnesses to the
respiratory system, which go from allergy to severe pulmonary damage. Particulary, breathable
particles (from 0,5 μm to 5,0 μm sizes) cause damages to the respiratory system. The penetration
and the deposition are the reason for the damages to the pulmonary alveolus.
The industrial activity is the main responsible for the most part of the breathable particles emission.
Because of that, Venturi scrubbers have been incorporated to the industrial process due to their high
efficiency for particle collection.
Venturi scrubbers are gas-atomizing devices. They are mechanical devices which rely on shearing
and impaction forces to break water into fine droplets. Those droplets in contact with the particles,
will collected them.
This work consists of a Venturi scrubber of circular section operating horizontally, with liquid
injection through a single orifice located in the scrubber throat. The experiments will analyse the
influence of the length throat, gas velocity, liquid flow and particles sizes on the Venturi´s
collection efficiency.
Thermal Decomposition and Solid Characterization of Calcium Oxide in Limestone Calcination
Authors: Soares Bruno D. , Hori Carla Eponina , Batista Carlos E.A. , Henrique Humberto Molinar
Published: March 2009

This work is concerning to production of quicklime (CaO) from thermal decomposition
of the calcite limestone (CaCO3) using analytical and instrumental techniques (TGA and MS) to
evaluate kinetic and thermodynamic effects as well as heat/mass transfer associates with the process
operation. On the other hand, experiments of morphologic, structural and textural characterization
(XRD, SEM and BET surface area) were carried out in order to evaluate the quality of the
quicklime produced. Under experimental studied conditions it was observed that carbon dioxide
(CO2) inhibits the thermal decomposition reaction rate. In addition, it was observed that steam
(H2O) can catalyze this reaction but it can also cause sintering of the oxide formed. It was also
observed that the calcination reaction is greatly limited by mass transfer effects and that the
controlled thermal decomposition generates an increase in the solid porosity. The formed CO2 have
also increased the sintering phenomena in the oxide structure, resulting in less reactive quicklime.
Synthesis of Superconducting Ceramics Hg0.82Re0.18Ba2Ca2Cu3O8+δ with Different Values of δ
Authors: Martinez Luís Gallego , Rossi J.L. , Orlando M.T.D. , Passos C.A.C. , de Melo Francisco Cristóvão Lourenço , Correa H.P.S.
Published: March 2009

Samples of the superconducting ceramics Hg0.82Re0.18Ba2Ca2Cu3O8+ were prepared by
solid-vapor reaction technique. The preparation of the ceramic precursor started with a mixture of
Ba2Ca2Cu3Ox and ReO2 powders with molar ratio 1:0.18. The precursor material was submitted to
annealing under three different partial pressures of oxygen using a mixture of oxygen/argon at
ratios: 5/95 (sample A), 10/90 (sample B) and 15/85 (sample C). X-ray powder diffraction analysis
of the precursors identified the phases BaCuO2+x, Ba2Cu3O5+x, Ba4CaCu3O8+x, Ca2CuO3 and
Ca5Re2O12 at different ratios in the samples, indicating an increment in the oxygen content from
sample A to sample C. Finally, the precursors with different oxygen contents were blended with
HgO at molar ratio 1:0.82 and treated in a sealed high pressure furnace to produce the high Tc
superconducting ceramics. Rietveld refinement of XRD data showed differences in the crystal
structures of the samples. The measurement of thermopower at room temperature resulted in distinct
values, confirming the different oxygen sample doping.
Study of Preforms of Quartzite for Production of Ceramic Matrix Composites
Authors: Chinelatto Adriana Scoton Antonio , Justus R. , Chinelatto Adilson Luiz , Nadal F.M.C.N. , Berg E.A.T.
Published: March 2009

The ceramic matrix composites (CMCs) can be fabricated by the pressure infiltration
technique. In this work it was studied porous preforms of quartzite that were infiltrated with
aluminum liquid. For to produce the more resistant preforms of quartzite, it was additioned different
quantities of bentonite (5 and 10%) and the preforms were firing at 1100°C and 1200°C. For the
composites production, the melted aluminum was introduced into preforms under a pressure of 7
MPa. The characterizations of the composites were made by X-ray diffraction, scanning electron
microscopy, and flexure strength. All the preforms studied presented sufficient strength for support
the pressing during the process of squeeze casting. The results of X-ray diffraction of composites
showed the presence of alumina, silicon and aluminum and fully interpenetration aluminum-siliconalumina
composites were obtained by infiltration.
Alumina Porous Ceramics: Mathematical Behavior at Different Commercial Starch Concentration
Authors: Fernandes Rodrigo Sampaio , de Campos Élson , Minatti José Luiz , Santana Jerusa Góes Aragão , Mota Rogério Pinto
Published: March 2009

Several researches have been developed in order to verify the porosity effect over the ceramic
material properties. The starch consolidation casting (SCC) allows to obtain porous ceramics by using
starch as a binder and pore forming element. This work is intended to describe the porous mathematical
behavior and the mechanical resistance at different commercial starch concentration. Ceramic samples
were made with alumina and potato and corn starches. The slips were prepared with 10 to 50 wt% of
starch. The specimens were characterized by apparent density measurements and three-point flexural test
associated to Weibull statistics. Results indicated that the porosity showed a first-order exponential
equation e-x/c increasing in both kinds of starches, so it was confirmed that the alumina ceramic porosity
is related to the kind of starch used.
Study of Alternative Materials to Minimize Erosion in Heat Exchanger Tubes Used in Thermoelectric Generators
Authors: Arnt A.B.C. , da Silva Paula Marcos Marques , da Rocha Márcio Roberto , Angioletto Elidio , Zanini L.C. , Miranda R. , Zanelatto C.C. , Felippe L.
Published: March 2009

The machinery used in coal thermoelectrical plants usually is submitted to erosive wear.
The erosive wear occurs mainly in the metallic pipe set of heat exchangers due the flow of hot gases
carrying erosive particles. Jorge Lacerda’s thermoelectrical complex at Capivari de Baixo city holds
seven power units, where two units use approximately 20 000 ASTM A178 heat pipes. The set is
submitted to a semester maintenance schedule (preventive and corrective) where the damaged pipes
are changed. So, in this work a set of erosive wear accelerated tests according ASTM G76 were
performed in order to develop and specify materials and methods to diminish the erosive action
caused by the combustion gases over the heat pipes. Specimens were coated with WC12Co and
Cr3C2-25NiCr alloys using the HVOF technique and the coated specimens were tested at 450°C, the
heat pipes working temperature. Silica was used as abrasive material at 30° and 45° impact angles,
simulating a harder erosive condition than the real condition. The best performance coating at
laboratory scale was later used in field condition. The results showed the coated specimen
performance is better than the ASTM A178 alloy. The erosion resistance of the Cr3C2-25NiCr and
WC12Co coatings is eight times higher than the uncoated alloy, and the coatings also presented a
better corrosion resistance. This feature is important, because despite the erosive action the
circulating gases also present a large amount of sulfur in their composition. Sulfur at lower
temperatures forms H2SO4, causing intense corrosion of the pipes located at the heat exchangers
colder parts. Based on the results and considering the coating costs the Cr3C2-25NiCr alloy was
selected to coat a set of pipes mounted at the region of the heat exchanger with the most intense
erosive wear. At the moment these coated tubes are in field operation and under observation
regarding their performance in comparison with the uncoated pipes located at the same heat
exchanger. The real operation conditions of the coated pipes will be estimated from the field life
cycle analysis, and after all the cost-benefit of the studied coating.
High Temperature Properties of Silicon Nitride with Neodymium Oxide Additions
Authors: dos Santos Claudinei , Reis Danieli A.P. , Araújo José A. , Silva Cosme Roberto Moreira
Published: March 2009

Silicon nitride samples were formed by pressureless sintering process, using neodymium oxide as
sintering aid. The short term compressive creep behavior was evaluated over a stress range of 50-300 MPa
and temperature range 1200-1350 0C. Post sintering heat treatments in nitrogen with a stepwise decremental
variation of temperature were performed in some samples and microstructural analysis by X-ray
diffractometry and Transmission Electron Microscopy showed that the secondary crystalline phases which
form from the remnant glass is dependent upon heat treatment. For the non heat treated samples, glassy
regions were revealed, by centered dark field images, using diffuse scattered electrons, to be located at three
and four point grain junctions. No direct evidence of microstructural changes involving dislocation
generation or motion was detected in the stress and temperature range studied. Stress exponents near unity,
related to grain boundary accommodation processes were obtained for low temperatures and for heat treated
samples. The behaviors for the heat treated samples were correlated in terms of depletion of metallic rareearth
ions and impurities from grain boundaries and triple junctions, with subsequent crystallization of the
primary glass. The non heat treated samples showed higher creep rates at higher stresses and temperatures.
The deformation processes in these cases were correlated to stress concentrations at grain boundary and
triple point junctions, caused by grains rotation and sliding, accommodated by cavitation.
Effect of the Two-Steps Sintering in the Microstructure of Ultrafine Alumina
Authors: Chinelatto Adriana Scoton Antonio , Manosso Milena K. , Pallone Elíria Maria Jesus Agnolon , Chinelatto Adilson Luiz
Published: March 2009

The control of the heating curve to manipulate microstructure during sintering is a way
that has being studied and it presents advantages such as simplicity and economy. In this work, it
was studied the sintering in two-steps of a commercial ultrafine alumina. For this, the alumina
power was deagglomerated in milling ball and the specimens for sintering were pressed. Sintering
was performed in a dilatometer, with constant heating rate of 15°C/min up to 1500°C. By these
results, heat treatment temperatures for two-step sintering were defined. The sintering specimens
were characterized through the apparent density measures using Archimedes method, the grain size
measures using image analysis program and microstructural analysis using a scanning electron
microscope. The results showed that the two-step sintering influence in the development of the final
microstructure and permit the control of the grain size and density.
Synthesis and Characterization of Ruteno-Cuprates by Solid State Reactions
Authors: Gimenez J.M.A. , Grandini Carlos Roberto , Jurelo A.R.
Published: March 2009

A new class of hybrid ruteno-cuprates – such as Ru-1212 and Ru-1222 – was discovered
in 1995 by Bauerfeind and collaborators. These materials present superconducting and magnetic
states at low temperatures, an atypical duality in other superconductors. The superconductivity is
more easily observed in Ru-1222, while Ru-1212 is a more problematic case, due to the strong
effects of the preparation details in its superconducting properties, becoming the material
superconductor or not. Ru-1212 presents a critical temperature that can vary between 0 and 46 K,
depending on the preparation conditions, and a temperature of magnetic transition of around 132 K.
The samples were prepared through solid state reactions, by using a mixture of high purity powders,
followed by calcination and sinterization in the nitrogen and oxygen atmospheres. This paper shows
the preparation process of Ru-1212 samples, followed by their structural and magnetic
characterization.
Morphological and Luminescent Characteristics of ZnO Nanopowders Doped with Europium
Authors: Barros T.S. , Barros Bráulio Silva , Alves S. , Kiminami Ruth Herta Goldsmith Aliaga , Lira Hélio Lucena , de Melo Costa Ana Cristina Figueiredo
Published: March 2009

Zinc oxide was obtained by combustion reaction synthesis method using microwaves
energy to provide ignition to the mixture of zinc nitrate, europium and urea. The influence of the
europium concentration on the structure, morphology and luminescence characteristics of the ZnO
powders was investigated. The proportion of each reagent and fuel was calculated based on the
propellants chemistry concepts. The solutions were mixed in a vitreous silica basin and submitted of
external heating in a microwaves oven until self-ignition occurred. The resulting powders were
characterized by X-ray diffractometer (XRD), granulometric distribution, scanning electronic
microscopy (SEM) and emission spectroscopy. The XRD results showed the formation of ZnO:Eu3+
as main phase and Eu2O3 as secondary phase. The powder presented morphology constituted of fine
particles agglomerates (<100nm) and red luminescence characteristic from Eu3+ ion.
Study and Optimization of Reaction of Hydration of Calcium Oxide to Produce Slaked Lime Suspension
Authors: Silva Alaine Cardoso , Parreira Priciane Martins , Henrique Humberto Molinar , Avelar Carlos Eduardo Batista , Damasceno João Jorge Ribeiro , Hori Carla Eponina
Published: March 2009

Slaked lime is a suspension of hydrated lime in water that can contain up to 40% of
solids in suspension. The quality of the suspensions of slaked lime depends on the quality of lime
used and on a careful choice of the conditions during the hydration process. A high quality slaked
lime is a product with a small quantity of insoluble residues, high specific surface area, high
alkaline content and small particle size. Therefore, the objective of this work was to study the best
conditions of temperature and concentration to produce a superior slaked lime. A statistic analysis
was performed using the experimental results in order to optimize the operational conditions of the
hydration process. The use of hydration water around 74 °C, of small particles of CaO (0.144 mm)
and of a CaO/H2O ratio around 220 g/L contributed to the production a slaked lime suspension of
fine quality.
Performance of a Quartz Fiber Filter Operating in the Filtration of Gases at High Temperatures
Authors: Silva G.M.C. , Moreira E.A. , Innocentini M.D.M. , Coury José Renato
Published: March 2009

Experimental results describing the pressure drop and collection efficiency of a quartz
micro-fiber filter are presented in this study. The filter utilized had a porosity of 0.698 and mean
fiber diameter of 1.1!m. For the tests performed, the filter was a disk with an effective diameter of
3 cm. The permeability tests of the filters were measured by varying the superficial gas velocity
from 0.013 to 1.49m/s and the temperature from 26.5 to 666oC. The collection efficiency tests were
accomplished for temperatures ranging from ambient to 700oC at a filtration velocity of 0.05 m/s.
The test powder utilized was a phosphate rock concentrate with a density 2973 kg/m3 and average
diameter of 4.6!m. The permeability test results showed that, for the same gas velocity, the pressure
drop increased with the gas temperature. This dependence was reflected in the measured values of
the permeability constant, k1, which increased with temperature. The experimental points were well
fitted by a linear correlation. The filtration tests also showed a clear dependence between filter
efficiency and test temperature: smaller filter efficiencies were obtained as the gas temperature was
increased.
Evaluation of the Metakaolin Pozzolanic Reactivity in Cement Pastes
Authors: da Cunha Armando Lucas Cherem , Gonçalves Jardel Pereira , Cartledge Frank K. , Toledo Filho Romildo Dias , Dweck Jo
Published: March 2009

The pozzolanic reactivity of a commercial metakaolin (MK) manufactured in Brazil, was
evaluated in pastes prepared with a type II Portland cement, when used in cement substitution
degrees from 10 to 40 mass % by thermal analysis techniques. The reactivity during the early stages
of hydration was studied in real time from Non-Conventional Differential Thermal Analysis
curves, normalized by the effect of the specific heats of the raw materials. The total pozzolanic
reactivity after 28 days of hydration was evaluated by the calcium hydroxide consumption,
calculated from thermogravimetric and derivative thermogravimetric curves of the pastes, obtained
on cement oxide calcined basis. This also allows one to a more accurate determination of the
uncombined and total combined water in the pastes than usual procedures. The MK pozzolanic
reactivity during the early stages and after a month is proportional to the cement substitution degree
in the pastes.
Prototyping of Image-Based Inspection Mechanisms by CAD and Virtual Reality Technology
Authors: Hsu Quang Cherng
Published: March 2009

Image-processing technology is widely used in industry for automatic inspection and
measurement through the capturing of object images by CCD (Charge-Couple Device) cameras and
the built-in algorithms. VR (Virtual Reality) is a high-end user interface that involves real-time
simulation and interactions through multiple sensorial channels. Three important characteristics of
VR are: immersion, interaction, and imagination which enable the users more direct and useful
communications with manufacturing prototyping systems.
In this paper, an image processing system was developed for measuring small parts such as 3C
rivets automatically. If using optical sensors to measure such small parts, the mechanism is
complicate. However, if using image process technology, the mechanism is simple and the
measurement is efficient. All we have to do are to develop measuring algorithms as well as
computer programs. A VR-based image processing system was also developed by importing 3D
CAD objects and applying the relationships between these objects. Therefore, the image processing
algorithms as well as the layout of the measurement system can be tested by using the proposed VR
system without any real machine such as transfer mechanism, CCD camera, and computer with
image processing program.
Experimental Studies of Meniscus Dynamic Behaviors in a Squeeze-Mode Piezoelectric Inkjet Printhead
Authors: Leu Tzong Shyng , Lin Jan Hua
Published: March 2009

Meniscus dynamic behaviors, as well as its optimal waveform of driving signal, in a
squeeze mode piezoelectric inkjet device are studied in this paper. To use the squeeze mode
piezoelectric inkjet device as a drop-on-demand dispenser, the driving signal is trapezium waveform.
The parameters in a trapezium waveform of the driving signal include rise time (trise), dwelling time
(tdwell), fall time (tfall) and voltage (Vp). Among these parameters, the most important parameter of
driving signal is the dwelling time. To demonstrate the importance of dwelling time, a LED signal
synchronized with the driving signal is used to visualize the instantaneous meniscus shape under a
microscope. Experimental results show the meniscus oscillation at beginning and droplet ejection at
the later phase. It is found there is an optimal dwelling time. At the optimal dwelling time, droplet
ejects in a minimum time and its ejection velocity reaches the maximum. The optimal dwelling time
can be further identified it relates to a pressure wave oscillation within the device. The optimal
dwelling time can be approximated as the length (L) of the piezoelectric inkjet device divide by the
speed of sound (c) in the dispensed fluid.
Chemical-Mechanical Polishing of Wafers with Copper Film by Nano-Scale Abrasives
Authors: Tsai Jhy Cherng , Kao Jin Fong
Published: March 2009

In this paper, experiments are designed and conducted to investigate the effects of abrasive
size for Chemical-Mechanical Polishing (CMP) of copper film under different additives in
HNO3-based polishing slurries. Alumina modified colloidal silica 100S (φ26nm), 200S (φ40nm) and
Al2O3 (φ90nm), are used as polishing abrasives in this study. Experiments showed the following
results. (1) With citric acid as an additive to slurry, the removal rate (RR) of the CMP process
increases with abrasive size. Surface quality, however, becomes worse at the same time. (2) With
benzotriazole (BTA) as an additive, RR of the slurry with Al2O3 powder is slightly higher but it does
not increase with the abrasive size in general. Surface quality tends to be worse at the same time
though it is not as strong as that in the slurry with citric acid as the additive. (3) The size effect of
abrasive on RR with citric acid as additive is stronger than that with BTA.
Simulation of Dendritic Growth in Solidification of Al-Cu Alloy by Applying the Modified Cellular Automaton Model with the Growth Calculation of Nucleus within a Cell
Authors: Peng Hsiun Chang , Chao Long Sun
Published: March 2009

Rather than designated directly as solid if the micromesh (or cell) larger than a nucleus is
chosen as the nucleation site, the growth of a nucleus in the cell is considered in the application of
the modified cellular automaton model to simulate the evolution of dendritic microstructures in the
solidification of Al-Cu alloy. The growth velocity of a nucleus or a dendrite tip is calculated
according to the KGT (Kurz-Giovanola-Trivedi) model, which is the function of the undercooling.
In this study, the dendritic microstructures, such as the free dendritic growth in an undercooled melt
and the dendritic growth in the directional solidification, are simulated with the modified growth
algorithm in the nucleation cell. The simulated results for the temporal and final morphologies are
shown and are in agreement with the experimental ones.
The Study of Effects of Cutting Parameters and PVD-Coatings on Tool Life of Micro End Drill by Using Taguchi Method
Authors: Liang Yu Teng , Chiou Yih Chih
Published: March 2009

In this study, a serial of dry milling experiments of 6061 aluminium alloy using single
edge rhombus micro end mills were performed. The purpose is to examine the influences of various
control factors on tool wear. Control factors under investigation include coating layer, side
clearance angle, feed rate, and spindle speed. We applied Taguchi method to design the experiment
in order to derive an optimum combination of cutting parameters quickly. During the milling test,
we fixed depth of cut at 0.2 mm and width of cut at 0.50 mm to investigate the correlation among
side clearance angle, feed rate, spindle speed and coating layer. Upon completion of each milling
test, the cutting-edge wear and flank wear were measured in offline by the aforementioned tool
microscope. The experimental results show that among the four control factors, side clearance turns
out to be the most important one. By using TiCN-coating and setting side clearance angle at 10
degree, spindle speed at 6000 rpm, and feed rate at 0.0125 mm/rev, the micro end mills generate
least wear and thus have longer tool life.
Experimental Study on Five-Axis Machining Parameter for NAK80 Die Steel
Authors: Chen Cheng Shun , Huang Chi Hui
Published: March 2009

The surface quality and contouring accuracy of die cavities directly influences the surface
roughness of the products. Different types of complex surfaces of products have become popular in
product design in recent years and consequently 5-axis machining techniques become a mainstream
in the manufacturing of the die and moulds used in products mentioned above, because of their
features and flexibility. This research applies Taguchi method to find out a set of optimal machining
parameters in five-axis milling process. The table rotating-tilting type five-axis machine is used to
perform the experimental cutting. The cavity of die is modeled as convex half spherical surface, and
the material of die is NAK 80 die steel. The four parameters studied are cutting speed, feed rate,
tool paths, and contact points, and each of these factors has three levels. The target of this study is
the feature of smaller-the-better that is minimization of the surface roughness. The experimental
results show that the optimal parameters are moderate cutting speed and contact points, higher feed
rate, five-axis tool path. ANOVA analysis indicates that the tool path influences the surface
roughness most, which accounts for about 86%. Using optimal parameters to machine a roughly
machined concave spherical surface can reach its roughness to 0.234μm, and the roundness error
about 0.0314mm. It is believed that the results and method presented in the paper give a good
reference for industry applied.
Fast Nanometer Positioning of Heavy Loads Using a Hybrid Driver
Authors: Hsieh Chen , Yang Cang Chin , Huang Chen Chiu , Chen Chih Hong
Published: March 2009

Current motion tables can hardly exhibit the capabilities of positioning with nanometer
precision and carrying heavy loads simultaneously. This is mainly because that the driver used to
drive the table cannot fulfill the requirements needed for driving an ultra precision system without
sacrificing the power it can offer. In this research, the concept of a hybrid driver is introduced and
tested. This driver is basically a combination of a linear amplifier and an on-off large power supply.
Although there are still some defects need to be overcome, preliminary experimental tests have shown
that this kind of driver does have potential to carry heavy loads to do fast and long distance
positioning with nanometer precision and in-position vibration.
The Application of Rapid Prototyping for the Design and Manufacturing of Transtibial Prosthetic Socket
Authors: Hsu L.H. , Huang G.F. , Lu C.T. , Lai C.W. , Chen Y.M. , Yu I.C. , Shih H.S.
Published: March 2009

This study aims to employ the technology of rapid prototyping for the development of a
process that is to assist a prosthetist for easily designing and manufacturing a prosthetic socket for
specific transtibial amputee. Currently, the production of prosthetic socket still depends on
prosthetists’ skills and expertise. To improve its tedious process, quality uncertainty, and lack of
experienced prosthetists, the benefits of using rapid prototyping (RP) technology together with
computer-aided systems will be expecting goals. This article demonstrated the feasibility of
producing RP sockets using a fused deposition modeling (FDM) machine, and a prototype system that
allows a prosthetist to easily design prosthetic sockets has been developed. This proposed
computer-aided engineering process, which is plaster-free method, is expected to replace the manual
process of conventional approach of fabricating prosthetic sockets. Furthermore, since thin-layer RP
socket is easily broken, coating a resin layer on RP socket to enforce its strength is underway.
Experimental Analysis for the Low-Temperature Growth of Poly-Si Films by Using Double Excimer Laser
Authors: Chao Long Sun , Chen Yu Ru
Published: March 2009

This paper is to investigate a double splitting excimer laser technique for making poly Si
films. In this research, a KrF excimer laser of 248 nm in wavelength is used to irradiate a-Si films of
0.1 m in thickness on glass substrate to produce poly-Si ones. The control parameters are laser
intensity (200~500 mJ/cm2), laser pulse number (1~2 shots) and delay time between two shots (one
nanosecond). Average grain sizes from SEM photos are used to analyze the effects of these
parameters. Firstly, in the excimer laser experiment, different laser fluences are utilized to study the
effect on the microstructure of the silicon film. Purely from the viewpoint of heat transfer, the Si film
obtains more energy has the slower cooling or solidification rate, which results in the larger grain.
From the experimental results, it can be found that the grain size increases until the laser fluence
increases up to the critical value of complete melting, which limits the grain growth method of energy
increase. In this work, a double-splitting-laser method is proposed. In the method, a laser pulse from
an excimer laser is divided into two pulses by a beam splitter. The cyclic optical path is used to control
the delay time of the second pulse. Optical mirrors and optical attenuators are utilized to adjust the
energy density of these two laser pulses. The delay time between these two pulses is changeable and
controlled in the order of nanosecond. The second pulse is applied when the Si film is solidifying after
the irradiation of the first one. This could enhance the solidification time and enlarge the grain size of
the poly-Si film.
Eliminating Hysteresis Effect of Force Actuator for Profiler Design with Rate Inner Loop Compensation
Authors: Lin Jium Ming , Chang Po Kuang
Published: March 2009

The key point of this research is to use Linear Velocity Transducer (LVT) to detect the
vertical velocity of the stylus probe for the inner-loop damping and transient control of a force
actuator. This improvement has been verified by MATLAB simulation and practical implementation
of a surface profiler to reduce the hysteresis effect of the force actuator.