bluuebunny/crossref_metadata_2025 huggingface dataset:
Improvement of Consumer Properties and Stability of the Technological Process of Hot Rod Stock Production
Authors: Mazur Igor
Published: March 2009

High-speed automated systems of management and control which include mathematical
models of technological processes nowadays serve as a basis in the manufacture of competitive
products in different fields, including metallurgy. A reliability of such systems and reproducibility
of results finally provide for the stability of complicated metallurgical processes. To secure the
stability of the technological process of manufacture of high quality products and introduction of
new product ranges, the issues of revamping of a Hot Rolling Mill are still one of the priorities of
modernization of the JSC «NLMK» (NLMK).
Commissioned at the end of the 60s, 2000 Mill during the last years was subject to fundamental
modernization when new equipment and automated systems were installed to measure parameters,
collect and process information. However, these means are sometimes used for a local control based
on the disturbance principle to return the process parameters to the set range, while the information
systems exist only for the operative registration of the production flow. This is in fact necessary, but
nowadays it is evidently not enough. Especially, at introduction of end-to-end technologies of metal
production. To effectively manage the quality of metal production at all stages of end-to-end
technology, we witness at present a shortage not of technical means, but of artificial intelligence,
that is, a set of algorithms and monitoring programs which can solve the following basic tasks:
− forecasting the structure and qualities of the ready products based on the actual
parameters of treatment at each process stage;
− preventing adverse results of disturbances by correcting the further technological
operations (regimes);
− designing technologies during expansion of production range.
The Lipetsk State Technical University (LSTU) jointly with the NLMK Information Technologies
Department has developed a number of PC applications which have been successfully introduced at
2000 Wide Strip Continuous Mill [1]. Within the frameworks of this publication, we analyze two
main systems which determine the factors of the consumer qualities of the rolled stock, namely,
«Hot Rolled Stock Structure and Qualities Forecast System» and «Strip Surface Quality Control
System». The applications realized in these systems have a set of their own program modules.
Strength Analysis of Elastic Bar Based on ANSYS Simulation
Authors: Wu Sheng Nan , Yang Zhi Heng , Dai Guang Ze , Zhang Zhen Jiang , Zhang Lei , Dong Li Xin , Liu Li Ling , He Feng
Published: March 2009

This paper presents a simulation analysis of stress and strain of an underground rail
elastic bar using the commercial finite-element simulator ANSYS-10. Under constant compression
displacement of 10.4 mm or the fixed-plug-in displacement of 84 mm, the stress distributions are
examined by varying the boundary condition of the corresponding fixed-plug-in displacement or the
compression displacement. Results show that the maximum stress which is 1,490 Mpa occurs as the
compression displacement is 10.4 mm while the fixed-plug-in displacement is 84 mm. In addition,
in both group of scenarios the maximum stress is at the end of the arc of the elastic bar and exceeds
the strength limit of 60Si2Mn. While both the compression displacement and the fixed-plug-in
displacement affect the stress distribution and the maximum stress, it appears that the effect due to
compression displacement is much more significant.
Numerical Simulation on Temperature Field in Laser Welding for Aluminum Alloy with Different Thickness
Authors: Rong Yu Shu , Hui Xiong Jin , Ding Fan
Published: March 2009

By using FEA software-ANSYS, distribution of 3D temperature field in laser welding for
aluminum alloy with different thickness was simulated. In order to improve solution accuracy and
efficiency, the transition mesh was used. In view of the characters of laser welding, a travel heat
source combined with Gauss function was designed by analyzing both the temperature relativity of
the thermal physical parameters of material latent heat of fusion and the effect of convection
radiation and characteristics of different thickness on temperature field. By using high-temperature
thermocouple, the temperature field was measured. It is shown that the simulation results are in
accordance with the experimental results.
Study on Computer Emulation of PTFE’s Wearability Improvement by Al3+ Ion Implantation
Authors: Shao Jun Peng , Tang Hui , Zhang Yan Qin
Published: March 2009

The surface material of Elastic-metal pads(EMP) is PTFE which has poor wearability .
Ion implantation can improve the wearability of EMP surface .This paper investigated the
wearability improvement of the EMP’s surface by Al2O3/PTFE film which generated by ion
implantation. The accelerating voltage of the ion implantation apparatus is 40KV and the ion
emitting energy of aluminum is 20KeV. The dosages of three kinds of Al3+ ion beams in the study
are 1×1015 ions/cm2, 5×1015 ions/cm2 and 1×1016 ions/cm2 respectively. The aluminum ion’s
density is 10uA/cm2. The vacuum pressure of the ion implantation is 3×10-3Pa. The experimental
specimens modified by Al3+ ion implantation were tested by ESCA, XRD, AFM/FFM and
nanometer probe , which got the chemical bond, phase structure and friction coefficient of the film.
According to the experimental results, the mathematical model was built using the Fesow
Geometric Model and the Halind Rang Theory. The computer simulation was made in which SRIM
simulator program was employed. The ion implantation’s energy for the simulation is 20keV and
the material density of PTFE is 2.56g/cm³. In addition, the dose is 5×1015 ions/cm², the time interval
is 230 minutes and the velocity of Al3+ ion implantation is 2.15-2.20×1013 ions/minute. Finally the
simulation curves of particle distribution, energy distribution and impairment etc. were plotted and
discussed.
Deformation Twins and Stacking Faults in an AA5182 Al-Mg Alloy Processed by High Pressure Torsion
Authors: Liu M. , Roven Hans Jørgen , Murashkin Maxim Yu. , Valiev Ruslan
Published: March 2009

High-resolution transmission electron microscopy investigations revealed different types
of deformation structures in a nanostructured commercial Al–Mg alloy processed by high pressure
torsion at room temperature. Microtwins and stacking faults were detected within both
nanocrystalline grains and ultrafine grains. Full dislocations in the form of dipoles were observed
within grains and near the grain boundaries. Two twinning mechanisms previously predicted by
molecular-dynamics simulations were directly verified including the heterogeneous twins nucleated
by the successive emission of Shockley partials from grain boundaries and homogeneous twins
formed in the grain interiors by the dynamic overlapping of stacking faults. Hence, the formation of
full dislocations, stacking faults and twins in the present aluminum alloy subjected to severe plastic
deformation may be interpreted in terms of molecular-dynamics simulations based on generalized
planar fault energy curves for pure metal systems.
Implementation Status of Performance Demonstration for Nuclear Power Plant Piping Weld Ultrasonic Examination in Korea
Authors: Kim Yong Sik , Lee Hee Jong , Kim Se Kyoung
Published: March 2009

The ASME B&PV code section XI adopted the performance demonstration requirements
(Appendix VIII) for the ultrasonic examination of nuclear power plant piping weld in the 1989
winter addenda for the first time. Korea Electric Power Research Institute(KEPRI) and Korea
Hydro and Nuclear Power Company(KHNP) finished developing Korean Performance
Demonstration(KPD) system for the ultrasonic examination to apply pressurized light-water and
pressurized heavy-water reactor power plants piping weld in accordance with ASME code section
XI, appendix VIII on January 2004. KEPRI has been accomplishing the performance demonstration
for nuclear power plant piping weld ultrasonic examination in Korea from April 2004. This paper
describes the implementation status of the performance demonstration for nuclear power plant
piping weld ultrasonic examination in Korea.
An Investigation on Wetting Characteristics of Solder Particle for Solderable Electrically Conductive Adhesives (ECAs)
Authors: Kim Jong Min , Yang K.C. , Lee S.B. , Lee Seong Hyuk , Shin Young Eui , Chang Kyong Ho , Han J.G. , Eom Y.S. , Moon J.T. , Baek J.W. , Nam Jae Do
Published: March 2009

A novel electrically conductive adhesives (ECAs) with solder particle have been
developed. The kinetics of the curing reaction were investigated using isothermal differential
scanning calorimeter (DSC). The dynamic DSC scans were also conducted to investigate the
temperature dependant curing degree. The temperature dependant viscosity characteristic of
polymer was investigated using rheometer. The wetting characteristic of two solders on two kinds
of metals were investigated using an optical microscope. It was found that developed resin material
showed good fluxing capacity against Sn-Bi solder on Ni/Au and the wetting angles was about 24º.
Finite Element Analysis of the Formation Mechanism of Electrode Pitting in Resistance Spot Welding of an Aluminum Alloy
Authors: Chang Bao Hua , Du Dong , Zhou Y.
Published: March 2009

A finite element analysis was conducted to study the roles of temperature and pressure in
the formation of electrode pitting in resistance spot welding of an aluminum alloy. The distributions
of pressure and temperature were computed at the electrode tip surface. Results showed that the
highest temperature is always located at the center of electrode tip surface, while electrode pressure
is concentrated mainly at the edge of contact region. The location of the concentrated electrode
pressure coincides with that of electrode pitting, which indicates that the pressure concentration
plays a more significant role than the temperature in the formation of pitting.
The Failure Strength Evaluation on Resistance Welding Mixed Adhesive Bonding
Authors: Yoon Ho Chel , Kim Yon Jig , Park Han Ju , Lim Jae Kyoo
Published: March 2009

Failure strength evaluation on resistance welding mixed adhesive bonding was studied.
Tensile-shear tests were carried out with the single-lap specimen, using both resistance welding and
adhesive bonding. Peel tests were also carried out with DCB specimen. Composites were
manufactured using the polyester as a matrix and bamboo natural fiber layer as a reinforcement.
Adhesive bond, having bonding strength that remains unaffected by heat at resistance welding, were
selected. Generally, adhesive bond require a long curing time and have little strength before hardening.
Resistance welding helps weakness of adhesive bond both curing time and peel strength. And the
spew fillet of adhesive bonding also helps to release stress intensity of edge of joining. The failure
mechanism was discussed in order to explain higher peel and tensile-shear strength of resistance
welding mixed adhesive bonding.
Friction Stir Welding of Oxygen Free Copper and 60%Cu-40%Zn Copper Alloy
Authors: Park Hwa Soon , Lee Byung Woo , Murakami Taichi , Nakata Kazuhiro , Ushio Masao
Published: March 2009

The mechanical properties of the friction stir welds of the oxygen free copper (OFC) and
60%Cu-40%Zn copper alloy(60/40 brass) were investigated. The defect-free welds were obtained in
a relatively wide range of welding conditions; the tool rotation speed had rpm of 1000 to 2000 in
the OFC and 1000 to 1500 in the 60/40 brass, with the welding speed of 500 to 2000 mm/min. The
SZ hardness values of the OFC welds were almost the same or slightly lower than those of the base
metal. However, the SZ hardness values of the 60/40 brass in all welding conditions were much
higher than those of the base metal. The SZ hardness values of both metals increase with a decrease
in heat input. The tensile properties of the all-SZ showed relative correspondence to the variation of
the SZ hardness values.
Effect of Interstitial Elements on the Toughness of Ferritic Stainless Steel Weld
Authors: Lee Won Bae , Kim Jeong Kil , Park Joon Sik , Woo In Su , Lee Jong Bong
Published: March 2009

In this study, the toughness of 11Cr ferritic stainless steel weld was evaluated by DBTT
(Ductile-Brittle-Transition-Temperature) with the interstitial elements level. DBTT of the weld
increased with increasing interstitial level due to the formation of martensite phase and solidsolution
strengthening. Interstitial elements level should be limited by the adoption of back
shielding gas during welding process because increased C+N level detrimentally affects the
toughness of ferritic stainless weld. Adoption of Ar as back shielding gas lowered N content in the
weld.
Equivalent Pulsed GMA Power to 2 kW CW Nd:YAG Laser Power in Welding of Carbon Steel and Al Alloy
Authors: Qin Guo Liang , Wang Xu You , Lin Shang Yang
Published: March 2009

Based on the bead on plate test and the effects of heat input on weld penetration, the
equivalence between 2 kW CW (Continuous Wave) Nd:YAG laser power and pulsed GMA(Gas
Metal Arc) power and the effect of welding speed on their equivalent ratios in welding carbon steel
and Al alloy were studied. The studied results show that 9.8 kW pulsed GMA power is needed to
reach the same weld penetration depth with 2 kW CW Nd:YAG laser power for welding of low
carbon steel at v=1.2 m/min; for Al alloy, it is 3.92 kW pulsed GMA power. The equivalent ratios
of 2 kW Nd:YAG laser power and pulsed GMA power are 4.9~6.4 and 1.85~2.1 times at different
welding speed for low carbon steel and Al alloy, respectively. But their equivalent ratios have
different variations with welding speed; at which the equivalent ratio of low carbon steel increases
with welding speed and that of Al alloy decreases. The studied results offer the experimental
boundary of heat input for analyzing the effect of Nd:YAG laser power and pulsed GMA power on
laser+pulsed GMA hybrid welding process.
Development of Remote Welding System Using Fiber Laser
Authors: Kim Ki Soon , Jung Chang Ho , Chang In Sung , Lee Heui Bom
Published: March 2009

In recent years, many of automotive companies are using laser welding in car body
assembly shop. Even though laser welding is better than resistance spot welding in many points, its
application has been limited in special manufacturing areas. This paper describes a new laser
welding system named by Remote Welding System (RWS) developed at Hyundai Motor Company
and comprised of fiber laser, industrial robot and remote welding head. In this technology, welding
efficiency can be dramatically improved since its remote welding head where laser continuously
finds next welding stitches in advance. Therefore, positioning time of laser is near to zero. It is a
good solution for welding in mass production.
Laser Peening without Coating to Mitigate Stress Corrosion Cracking and Fatigue Failure of Welded Components
Authors: Sano Yuji , Sakino Yoshihiro , Mukai Naruhiko , Obata Minoru , Chida Itaru , Uehara Takuya , Yoda Masaki , Kim You Chul
Published: March 2009

The authors have applied laser peening without coating (LPwC) to metallic materials.
Compressive residual stress nearly equal to the yield strength of the materials was imparted on the
surface. Accelerating stress corrosion cracking (SCC) tests showed that LPwC had a significant
effect to prevent the SCC initiation of sensitized materials of SUS304, Alloy 600 and the weld
metal, Alloy 182. Push-pull type fatigue testing demonstrated that LPwC drastically enhanced the
fatigue strength of fillet-welded rib-plates of SM490A.
Optimization of Welding Conditions for Sealing of Lithium-Ion Battery by Pulsed Nd:YAG Laser
Authors: Kim Jong Do , Yoo Seung Jo , Kim Jang Soo
Published: March 2009

Laser material processing is a very rapidly advancing technology for various industrial
applications, because of its many advantages. A few of its major advantages, less yet better
controlled heat input, have been successfully exploited for the very critical application of aluminum
alloy welding. This study suggested the source of weld-defects and its solution methods in welding
a lithium ion battery with pulsed Nd:YAG laser. In the experiment, battery case has changed over
joint geometry from side welding to flat welding. In the case of an electrolyte inlet seal welding,
welding was carried out after pressing an Al ball and the degree of eccentricity, the contact length
and the gap are presented as major parameters. With the Al ball indent improvement, the
eccentricity and the gap were reduced and the contact length was increased. As a result of an
experiment, a sound weld bead shape and crack-free weld bead were obtained.
4th Wave of Modernization by Photon/Electron Technology and Development of Advanced Laser Integrated Manufacturing System (ALIMS)
Authors: Kutsuna Muneharu
Published: March 2009

High power lasers, including CO2 laser, Nd:YAG laser, Excimer laser, Diode laser, LD pumped
YAG laser, LD pumped Disk laser, LD pumped Fiber laser and Femto second laser, are now used as a modern
tool for industries as well as a computer alike in the 4th wave of modernization. Lasers are currently used
for welding, cutting, drilling, cladding, direct fabrication, marking, cleaning, micro-machining peening and
forming of materials in modernized factories. The joining speed (= product of welding speed and penetration
depth) of 45,000mm2/min for steel sheet can be obtained by a 10kW Yb: fiber laser and is that
of 50kW electron beam welding, which require the vacuum chamber. As a result of large numbers of research
and developments the Advanced Laser Integrated Manufacturing System (ALIMS) using high power diode
lasers has been developed and used for modernization in many industrialized countries.
The laser materials processing is now penetrated as a machining tool into many industries. In the
present paper, an advanced laser integrated manufacturing systems and its applications to industries such as
automotive, electronics, ship building and steel making industry are introduced. In addition, development of an
advanced laser integrated manufacturing system using a 2kW fiber laser for welding a car panel and “Laser
Roll Welding” system for dissimilar metal joints such as mild steel/high strength steel to aluminium alloys,
titanium to aluminium and steel to titanium, is described for modernization of industries. It will be a magnificent
for the industries. And the 4th wave of modernization and opto-mechatronics will be promoted more by
laser/photon technology in the future.
Fatigue Crack Growth Characteristics in Dissimilar Weld Metal Joint
Authors: Ki Ho , Kim C.S. , Jeon Y.C. , Kwun S.I.
Published: March 2009

The fatigue crack growth (FCG) in dissimilar weld metal joints between SA 508 Cl.3
low-alloy steel and AISI 316L stainless steel (SS) was investigated. The dissimilar weld metal joint
was made after buttering alloy 82 on the SA 508 Cl.3 side by gas tungsten arc welding (GTAW).
Alloy 82 welding consumable was selected to join these two metals. The fatigue crack growth rate
(FCGR) in each material in the dissimilar weld metal joint increased in the order: weldment, AISI
316L SS and SA 508 Cl.3, at the same stress intensity factor range, /K. As the crack propagated
across the AISI 316L SS and heat affected zone (HAZ) into the weldment or across the SA 508 Cl.3
and HAZ, into the weldment, the FCGR in the HAZ region did not change or decrease, in spite of
the increase in /K. The retardation in the FCGR in the HAZ region was discussed in terms of the
welding residual stress.
Weldability Studies on the Replacement Repair Welded Joints of a Damaged Steel Bridge
Authors: Chang Kyong Ho , Park H.C. , Lee Chin Hyung , Jang Gab Chul , Lee Sang Hyong , Choi E.H. , Shin Young Eui , Kim Jong Min , Lee J.H.
Published: March 2009

In recent years, the replacement repair welding, through which damaged bridges are
repaired by replacing of the damaged sections with new steel plates through cutting and welding
under in-service conditions, has been highlighted for its brilliant features i.e. it can be achieved
without incurring traffic dislocation. However, the validity of the repair method is not fully verified
because of its lack of safety and reliability. Moreover, repair method by welding inevitably involves
cutting and welding process, and the weldability of the replacement repair welded joints has not yet
been clarified. In this paper, the weldability of the replacement-repair-welded joints was
investigated in order to improve reliability in the repair welded joints of the aged steel bridge. A
Steel plate was extracted from the steel bridge after the period of prolonged service, and was
welded with a new plate, using replacement repair welding technique, in order to construct a
specimen. Flux Cored Arc Welding (FCAW) process was used to fabricate the double "V" butt
joints. Welded joints were characterized on the basis of chemical composition analysis, hardness
test and micro-structural analysis.
Effect of Strain Rate on Microstructural Evolution of Nano-Grained Copper in Accumulative Roll-Bonding Process
Authors: Lee Seong Hee , Kim Sang Shik , Han Seung Zeon , Lim Cha Yong
Published: March 2009

The effects of strain rate in rolling on microstructures and mechanical properties of a
nano-grained high purity copper processed by accumulative roll bonding (ARB) were studied. The
rolling during ARB was conducted with two kinds of strain rates (2.6sec-1 and 37sec-1). The
microstructural evolution of the copper with ARB proceeding was somewhat different in both
methods. However, the variation of mechanical properties with ARB was very similar to each other.
Microstructure of Magnetic Shape-Memory Alloys: Between Magnetoelasticity and Magnetoplasticity
Authors: Müllner Peter , Kostorz G.
Published: March 2009

Magnetic shape-memory alloys owe their exceptional properties primarily to the
accompanying effects of a martensitic phase transformation. The twinning disconnection as
elementary carrier of magnetic-field-induced deformation is the starting point of the present study.
A disconnection is a line defect similar to a dislocation but located at an interface and exhibiting a
step character besides a dislocation character. The mutual interaction of disconnections is fully
tractable by the theory of dislocations. Due to the martensitic transformation, a hierarchical twin
microstructure evolves, details of which are controlled through disconnection-disconnection
interaction. Depending on the mutual orientation of twin boundaries on different hierarchical levels,
twinning disconnections are incorporated in higher hierarchical twin boundaries forming
disclination walls, or they stand off individually from those interfaces. Disconnections which stand
off from interfaces contribute to magnetoelasticity, i.e. recoverable magnetic-field-induced
deformation. Disconnections in disclination walls contribute to magnetoplasticity, i.e. permanent
magnetic-field-induced deformation, if the twin thickness is large. In self-accommodated martensite
with very thin twins, resulting from a martensitic transformation without training, the deformation is
fully magnetoelastic and small. In single-domain crystals, resulting from effective thermo-magnetomechanical
training, the deformation is fully magnetoplastic and large. Between these limiting
cases, there is a continuous spectrum where, as a rule, the fraction of magnetoplastic strain and the
total strain increase with increasing effectiveness of training.
Effect of Nanocrystalline Structure and Polygonized Dislocation Substructure on Ti-Ni Martensite Lattice Parameters and Transformation Lattice Strain
Authors: Prokoshkin Sergey , Korotitskiy Andrey , Brailovski Vladimir , Inaekyan K.E.
Published: March 2009

The Ti-50.26 and 50.61at.%Ni alloys were cold-rolled with true strains from e=0.3 to 2.1.
Post-deformation annealing in the 200 to 500°C temperature range after a moderate deformation
(e=0.3) produced a polygonized dislocation substructure with various dislocation density and
subgrain size, while after severe plastic deformation (e=1.7-1.9), a nanocrystalline structure with
various grain size was formed in the B2-austenite. An X-ray diffraction study shows that lattice
parameters of B19'-martensite formed from (a) partially recovered and polygonized or (b)
nanocrystalline austenites differ from the corresponding parameters of the martensite formed from
quenched (recrystallized) austenite. This difference increases with nanocrystalline grain refinement
and with an increase in residual dislocation density and subgrain refinement. The maximum
martensitic transformation strain has the highest value for the martensite formed in recrystallized
austenite, and this value decreases with nanograin refinement and with an increase in dislocation
density and subgrain refinement.
Extending the Lifetime of Weldable Primers by Means of Chemical Inhibitors
Authors: Bastos A.C. , Lamaka Sviatlana V. , Zheludkevich Mikhail L. , Ferreira Mário G.S.
Published: March 2009

Pre-painted metal sheets (coil-coatings) are widely used in casings of household
appliances, roofs and side walls in buildings and body parts for the automotive industry. One of the
main problems of this type of material is the difficulty to weld it. In an attempt to overcome this
problem weldable organic coatings are being experimented. Primers with heavy loads of zinc
powder are being employed with success to spot-weld different components of an article. These
primers may also present an anticorrosive effect through the galvanic protection offered by the zinc
powder. However in aggressive conditions the zinc containing primers can corrode very fast and be
consumed in a short period of time. Work has been undertaken in order to extend the lifetime of
these primers but maintaining the welding and anticorrosive capabilities. The approach followed
here was the modification of primers by corrosion inhibitors that can provide additional active
protective effect. A set of organic and inorganic corrosion inhibitors was tested in order to partially
passivate the primer. The inhibition of corrosion of zinc and iron was also investigated.
Electrochemical testing was done with Electrochemical Impedance Spectroscopy (EIS) and the
Scanning Vibrating Electrode Technique (SVET). Results showed that soluble inorganic salts of
Ce(III) and La(III) and organic inhibitors like benzotriazole and mercaptobenzothiazole are good
candidates to increase the service life of weldable primers.
SRET Visualisation of Pyrite Corrosion and its Inhibition in Aerated Solution
Authors: Araújo L.P.S. , Santos Diogo M.F. , Sequeira César A.C.
Published: March 2009

In this work, the Scanning Reference Electrode Technique (SRET) was used to visualise
the pyrite corrosion by atmospheric oxygen and its inhibition by a thymol derivative. SRET has the
advantage over the potentiostatic and galvanostatic techniques of enabling in situ operation without
imposing any potential or current to the sample under study. SRET revealed that the inhibiting
effect is effective only if the sample is oxidised beforehand. It also revealed that pyrite corrosion by
oxygen is a localised process whereas that by Fe(III) is not local, thus the oxidation of pyrite by
atmospheric oxygen is not only due to the oxidative role of Fe(III). Adsorption of oxygen plays
probably a determining role. Studies are now carried on to evidence the intervention of galvanic
processes or catalysis phenomena occurring during the corrosion of natural conducting minerals and
industrial wastes. Their aim is to better understand the mechanisms and to propose remediation
processes.
Characterisation of the Mural Paintings from the Misericordia Church of Odemira (Portugal)
Authors: Valadas Sara , Tavares Deolinda , Coroado João , Silva António Santos , Pedro Jorge , Mirão José , Candeias António Estevao
Published: March 2009

Several mortars from mural paintings were collected from the Misericórdia Church of
Odemira and analysed by using different techniques namely X-ray diffraction, thermogravimetric
analysis with differential thermal analysis, SEM-EDX, optical microscopy, CHNS elemental
analysis and chemical analysis. Microfragments of paint layers were collected and analysed by
microchemical analysis. The results showed that the mortars are aerial lime mortars with siliceous
aggregates and that the pigments used were mainly pigments from local sources (red and yellow
ochre’s and malachite) and small blue.
Nanostructured Cermet Coatings with Enhanced Properties Produced by HVOF Thermal Spray
Authors: Dosta Sergi , Miguel J.R. , Guilemany J.M.
Published: March 2009

There is an increasing interest in the last years for materials with nanometric grain size
because of the enhanced properties that could be achieved when reducing to the nanometric
scale. Three coatings using conventional, nanostructured and bimodal (mixture of conventional
and nano) WC-Co powders were obtained through High Velocity Oxygen-Fuel (HVOF)
technique. The powders were sprayed under different spraying conditions in order to improve
trybological properties for nanostructured powders. The relationship between spraying
conditions and decomposition has been studied using in-flight measurements and XRD
techniques. The nanostructured coating showed more decomposition than the other ones during
spraying process, but this decomposition was reduced through the new conditions.
Nanostructured coating showed more hardness using producer conditions, but the bimodal
coating showed better abrasive and friction wear resistance. Nanostructured and bimodal
coatings also provided an enhanced corrosion protection to the substrate when compared with the
conventional one. An important improvement in the abrasive wear resistance for the
nanostructured coating was obtained with the new conditions, due to the reduction in the
decomposition.
Application of a Novel Modified Electrode Based on NaY-Encapsulated Co(PAN) Complex
Authors: Teixeira C. , Parpot P. , Neves Isabel , Fonseca António Maurício C.
Published: March 2009

CoPAN complex has been entrapped in the supercages of Y zeolite and the redox
properties of this zeolite-encapsulated complex were investigated by cyclic voltammetry with a new
method for the preparation of carbon toray-zeolite-modified electrode. Formation of the CoPAN
complex was ascertained by surface analysis (SEM, XRD), chemical analysis (CA), spectroscopy
methods (FTIR and UV/vis) and cyclic voltammetry in aqueous medium with zeolite-modified
electrodes. The cyclic voltammetry studies obtained with a zeolite-modified electrode shows
evidence for electroactivity restricted to boundary associated CoPAN complex.
Strength Improvement of Cordierite Foams by a Dip Coating Method
Authors: Silva Elisabete R. , Silva J.M. , Oliveira Fernando A. Costa , Ribeiro F.R. , Bordado João C. , Vaz M. Fatima , Ribeiro M. Filipa
Published: March 2009

The structure and morphological aspects of highly porous (higher than 90%) cordierite
(Mg2Al4Si5O18) foams, prepared by a direct foaming method, have been evaluated by Scanning
Electron Microscopy analysis. The resulting ceramic foams consisted of a three-dimensional array
of struts forming a well-defined open-cell structure. This type of structure seems very attractive for
catalyst support purposes. Attempts have been made in order to control the pore structure since it
directly affects the physical properties, namely the mechanical strength. In this respect, the use of a
dip coating method to improve the strength of the resulting foams was found to be effective in
reducing defects (e.g. pores, flaws) in the struts. Based on image analysis, estimated mean cell sizes
were about 550 µm whereas strut thicknesses varied in the range of 60-70 µm. The compressive
strength of the developed foams increased by one order of magnitude (0.1 to 1 MPa) by increasing
the relative density from 0.06 to 0.18.
MPT Influence on the Rheological Behaviour of Self-Flow Refractory Castables
Authors: Silva Abílio P. , Segadães Ana M. , Devezas Tessaleno C.
Published: March 2009

The success of a refractory castable is largely due to the quality of its properties and ease
of application. Self-flow refractory castables (SFRC), with high flowability index (>130%), can be
easily accommodated in a mould without the application of external energy, being ideal for the
manufacture of monolithic linings. SFRC castables without cement require a matrix of very fine
particles, which guarantees improved rheological behaviour and performs the role of the binder in
the absence of the refractory cement. The presence of the aggregate (coarse particles) hinders the
flowability index, but improves the castable mechanical strength and reduces firing shrinkage, and
also contributes to the reduction of the castable costs. The control of the maximum paste thickness
(MPT) allows the reduction of the coarse particles interference, minimizing the number of contact
points among the grains and avoiding the formation of an aggregate skeleton that impairs the
flowability of the mixture.
In the present work, 100% alumina SFRCs without cement were produced with a fixed matrix of
fine particles, whose particle size distribution was optimized using statistical techniques (mixtures
design and triangular response surfaces). Different aggregate particle size distributions were used,
with several MPT values, with the objective of evaluating which was the mean distance that
maximized the flowability index, simultaneously ensuring good mechanical strength for the
refractory castable. Ensuring a minimum surface area of 2.22m2/g, the mixtures reach the self-flow
turning point with a minimum water content and the maximum flowability is obtained for an
aggregate particle size distribution modulus of q=0.22, and consequently an optimized MPT value.
SFRC with high mechanical strength (>60MPa) were obtained.
Effect of TiO2 and SiO2 on Surface Reactivity of Calcium Phosphate Glasses in Simulated Body Fluid
Authors: Silva A.M.B. , Correia Rui N. , Oliveira J.M. , Fernandes Maria Helena F.V.
Published: March 2009

This study compares the in vitro behaviour in SBF of glasses from two different systems,
TiO2-CaO-P2O5 and SiO2-CaO-P2O5 with the same TiO2 and SiO2 molar content, in order to
evaluate the effect of TiO2 and SiO2 on the surface reactivity of those glasses.
The glass formation regions in both systems were observed for compositions with less than 40
mol% TiO2 and 40 mol% SiO2, respectively. Four glasses with similar TiO2 and SiO2 molar
contents have been selected for comparison. These glasses are equimolar in CaO and P2O5 with
TiO2 or SiO2 varying from 4 to 33 mol %.
Powder glasses were immersed in Simulated Body Fluid (SBF) and kept at 37°C for different times,
up to 14 days. Surfaces were observed by Scanning Electron Microscopy (SEM) and specimen ion
leaching to SBF was studied by Inductively Coupled Plasma (ICP) spectroscopy. Preliminary
spectroscopic studies by Raman were performed to identify the structure of the glasses.
For glasses of the SiO2-CaO-P2O5 system a significant dissolution of all ions was observed together
with the formation of phosphoric acid. In opposition, the immersion of TiO2-CaO-P2O5 glasses
produced a small Ca consumption and stable Ti and P concentrations, indicating the formation of a
Ca-P rich layer on these glasses.
The observed differences in the dissolution behaviour are tentatively explained in terms of the glass
structures obtained by spectroscopy.
Production and Characterisation of Metastable Al2O3-TiO2 Coatings Obtained by APS + Quench
Authors: Cano Irene G. , Dosta Sergi , Caldeira R. , Miguel J.R. , Guilemany J.M.
Published: March 2009

It is well known that microstructure evolution during rapid solidification depends on the
rate between undercooling and solidification velocity. Microstructural evolution in a nonequilibrium
solidification process depends critically on the melt undercooling and growth
(solidification) velocities of competing phases.
One way of obtaining metastable structures is by Thermal Spray Technology. Metastable coatings
can be produced starting from microstructured powders through Atmospheric Plasma Spray (APS)
technique, followed by a quenching route.
The initial powders are melted during the spraying and deposited over a substrate that is quenched
with nitrogen feeders, producing metastable coatings. The obtained coatings were characterized
using XRD, SEM, FESEM and TEM in the Thermal Spray Centre (CPT) of the University of
Barcelona. The properties of such coatings were studied by hardness, obtaining promising results.
Biodegradable Composites Applied to the Automotive Industry: The Development of a Loudspeaker Front
Authors: Campos Ana Rita , Cunha António M. , Tielas Alberto , Mateos António
Published: March 2009

The interest of the automotive industry on biodegradable and green composites is
increasing dramatically due two environmental legislation that obliges automakers to reduce the
disposal of waste from vehicles [1]. As an answer to this recent demand several research groups are
working on the development of these composites. This work shows the development of a
loudspeaker front made of two different biodegradable composites: PLA (polylactic acid) and SCA
(blend of starch and cellulose acetate) reinforced with different percentages of cellulose spent fibres.
The composites were previously extruded on a counter-rotating twin screw extruder and injection
moulded into tensile specimens. The mechanical properties of the produced tensile specimens were
assessed with an Instron Universal Testing Machine as well as the morphological aspects of the
materials, studied with optical and scanning electron microscopies. After these preliminary set of
tests, the best composites were chosen to produce the final parts (loudspeaker front). These parts
were injection moulded on a Ferromatik Milacron K85 injection moulding machine (850 kN
clamping force) and subjected to a wide set of automotive tests to evaluate their performance. The
best materials for this application proved to be the PLA reinforced composites, although there is still
a large window for improvement of properties, based on the engineering of the
matrix/reinforcement interface and also on the improvement of the thermal properties of the PLA
material.
Development of Boron Hydrides as Reinforcing Components for Composite Materials
Authors: Popov Vladimir A. , Zhizhin K.Y. , Malinina E.A. , Retivov V.M. , Staudhammer K.P. , Kuznetsov N.T.
Published: March 2009

In recent years, industries have increasingly demanded novel materials of low density
(and, therefore, weight) and high strength. Such materials are required for all kinds of transport,
especially for automobile and aviation industries. Lower weight vehicles would allow for reduced
fuel consumption, which increases the transportation efficiency (the economical point of view) and
a corresponding decrease of emission of pollutants to the atmosphere (the ecological point of view).
This is why the development of materials with decreased densities is of great importance. The aim
of this study was to develop novel materials as reinforcing elements for metal matrix composites.
Boron crystalline compounds are proposed to be used, including the derivatives of higher boron–
hydrogen anions BnXn
2- n = 10,12, X = H (in some cases – halogen, for example, Cl) as their
respective densities meet the criteria. The study pursued two goals: (i) to develop a method for
producing these boron hydrides and (ii) to investigate the structure and properties of these boron
hydrides.
Interfaces in Alfa Fibre-Polypropylene Matrix Composites
Authors: Paiva M.C. , El Gaied Anissa , Cheikh R.Ben , Cunha António M.
Published: March 2009

Model composites with Polypropylene (PP) as matrix and alfa fibres (cellulose-based
fibres obtained from the esparto grass of the subsaarian dry regions of Tunisia) were prepared for
fibre/matrix interfacial characterization studies. The matrices tested were PP and PP combined with
PP modified with maleic anhydride (PP-g-MA). The surface of the alfa fibres was treated by air
plasma treatment. The adhesion between the untreated and treated fibres and both matrices was
studied using the fragmentation test method. Composites with 10% weight of fibres were prepared
by melt extrusion and injection moulding, and the specimens obtained tested for tensile properties.
The fracture surfaces of the composites, obtained at low temperature, were observed by scanning
electron microscopy. The presence of a small concentration of maleic anhydride grafted to the
polymer matrix was found to be of the utmost importance for the establishment of a good
fibre/matrix interface. The air plasma treatment had a cleaning effect of the fibre’s surface.
Dynamic Mechanical Thermal Analysis of Flame-Retardant Unsaturated Polyester Nanocomposites: The Effect of Aluminum Hydroxide (ATH) and Nanoclays
Authors: Pereira Celeste M.C. , Nóvoa Paulo J.R.O. , Marques António Torres
Published: March 2009

This work reports the effects of nanoclays and aluminium hydroxide (ATH) on the
thermomechanical properties of an unsaturated polyester resin. Dynamic mechanical thermal
analysis in the temperature range from 25 to 150 °C has indicated the formation of different
structures for the different clay (1, 5 and 10 wt. %) and ATH loadings (50 and 100 wt. %)
investigated. The rubbery modulus increases with nanoclay and ATH content which indicates that
both nanoclays and ATH act positively on the final network density and consequently lead to
systems showing higher stiffness at higher temperatures. The mechanical loss peak value decreases
with either nanoclay or ATH content which seems to indicate that both nanoclays and ATH
improve network density. The glass transition temperature and the mechanical loss peak value
changes linearly with ATH content.
New PVC Matrix Towpregs and Composites
Authors: Torres L.M. , Nunes João Pedro , Silva João F. , Marques António Torres
Published: March 2009

A cost efficient powder coating technology developed in previous work [1-3] was
modified to produce glass fibre/polyvinyl chloride (GF/PVC) towpregs that were subsequently
processed by compression moulding and filament winding. The production of GF/PVC towpregs
was optimized and a process window established. The composite structures obtained were
submitted to mechanical testing and the results compared with the theoretical predictions made
using the classical laminate theory (CLT). The obtained results showed that the GF/PVC
composites properties are compatible with all major engineering applications.
Concentration-Dependent Photoluminescence and Raman of p-Type GaAs Grown in a Metallic-Arsenic-Based-MOCVD System
Authors: Díaz-Reyes J. , Galvan-Arellano Miguel , Peña-Sierra R.
Published: March 2009

This work presents the optical and structural characterization of p-type GaAs epilayers.
The gallium precursor was the organometallic compound trimethylgallium (TMG). The influence of
the doping in the optical and structural properties of the GaAs layers has been studied by
photoluminescence (PL) and Raman dispersion measurements. The range of analyzed hole
concentration was from 1017 to 1019 cm-3 as measured by the Hall-van der Pauw method. For
carrying out doping p-type, it was necessary to modify the hydrogen activity in the growth
atmosphere with the control of a H2+N2 mixture, which was used like transporting gas. The
photoluminescence response and Raman dispersion of the layers are strongly dependence of the
growth temperature, which were investigated based on the hole concentration. The PL response of
the layers shows two radiative transitions, band-to-band and band-to-C-acceptor at low hole
concentration and disappears at high concentrations. Raman scattering spectra show LO mode at
270 cm-1 for low doped samples and a LO-like mode at 290 cm-1 produced by the phonon-holeplasmon
coupling for high doped samples.
Electrochromic Studies of Prussian Blue Intercalated Compounds
Authors: Rodrigues L.F.F.T.T.G. , Sequeira César A.C.
Published: March 2009

The electrochromic response of the Prussian blue (PB) system is produced by the
electrochemical reaction of the colourless Everitt’s salt (ES), K2FeFe(CN)6, to form the blue
oxidation product, KFeFe(CN)6. Reviews on the electrochemistry of PB and related compounds are
available. Very little work, however, has been published on the quantitative aspects that affect film
stability. The reported electrochemical deposition conditions for PB film formation vary
considerably in terms of the electrochemical technique, pH, ferricyanide concentration, supporting
electrolyte, as well as composition and concentration of the iron (III) salt. In this study, most PB
films were prepared at ambient temperature from acidic K2SO4/H2SO4 (pH ≅ 2.0) solutions
containing either Fe(ClO4)3 or FeCl3 and K3Fe(CN)6, using potentiostatic conditions. Dramatic
increases in the film stability are obtained by simple acidifying; in fact, the switching speed
increased from about 2 seconds at a pH of 7 to about 0.2 seconds at a pH of 2. Cycle lifetimes of at
least 100,000 cycles were obtained in all of the acidified solutions. Factors such as the solution pH
and heat treatment of the PB film also affect the position and shape of the observed cyclic
voltammetric peaks. Summarizing, the PB films prepared by an electrodeposition method appear to
be very promising for reaching stable, reversible and fast switching time (2 Hz) materials.
New Experimental Facts Concerning the Thermally Stimulated Discharge Current in Dielectric Materials
Authors: Neagu Eugen R. , Carmo Lança M. , Marat-Mendes José N.
Published: March 2009

The thermally stimulated discharge current (TSDC) method is a very sensitive and a very
selective technique to analyze dipole disorientation and the movement of de-trapped space charge
(SC). We have proposed a variant of the TSDC method, namely the final thermally stimulated
discharge current (FTSDC) technique. The experimental conditions can be selected so that the
FTSDC is mainly determined by the SC de-trapping. The temperatures of the maximum intensity of
the fractional polarization peaks obtained at low temperature, in the range of the local (secondary)
relaxation, are in general about 10 to 20 K above the poling temperature. Measurements of the
FTSDC in a wide temperature range demonstrate the existence of an apparent peak at a temperature
Tma shifted with about 10 to 30 K above the charging temperature Tc. The shift of Tma with respect
to Tc depends on the experimental conditions. The peak width at the half maximum intensity
decreases as Tc increases and the thermal apparent activation energy increases. The variations are
not monotonous revealing the temperature range where the molecular motion is stronger and
consequently the charge trapping and de-trapping processes are affected. Our results demonstrate
that there is a strong similarity between the elementary peaks obtained by the two methods, and the
current is mainly determined by SC de-trapping. Even the best elementary peaks are not fitted very
well by the analytical equation, indicating that the hypothesis behind this equation have to be
reconsidered.
New Amorphous Oxide Semiconductor for Thin Film Transistors (TFTs)
Authors: Fortunato Elvira , Barquinha Pedro , Gonçalves Gonçalo , Pereira Luís , Martins Rodrigo
Published: March 2009

Thin film transistors (TFTs) have been produced by rf magnetron sputtering at room
temperature, using non conventional oxide materials like amorphous indium-zinc-oxide (IZO)
semiconductor, for the channel as well as for the drain and source regions. The obtained TFTs
operate in the enhancement mode with threshold voltages of 2.4 V, saturation mobility of 22.7
cm2/Vs, gate voltage swing of 0.44 V/dec and an ON/OFF current ratio of 7×107. The high
performances presented by these TFTs associated to a high electron mobility, at least two orders of
magnitude higher than that of conventional amorphous silicon TFTs and a low threshold voltage,
opens new doors for applications in flexible, wearable, disposable portable electronics as well as
battery-powered applications.