bluuebunny/crossref_metadata_2025 huggingface dataset:
Transport and Relaxation Study of Ionic Phosphate Glasses
Authors: Bury Peter , Hockicko Peter , Jamnický Miroslav
Published: March 2009

Dynamic processes in glassy materials with ionic conductivity are extremely important
since the ion transport significantly affects their practical performance. Conductivity measurement
and dielectric relaxation spectroscopy are powerful techniques that reflect the essential features of
the transport and relaxational dynamics of the mobile ions that encounter different kinds of site and
ionic hopping motion connected with charge mobility. Acoustic spectroscopy is another technique
for the study of relaxations in glasses. In this contribution the acoustic and electrical relaxation
processes are compared on identical ionic phosphate glasses of the systems CuI-CuBr-Cu2O-P2O5
and CuI-CuBr-Cu2O-P2O5-MoO3 containing Cu+ ions. The acoustic attenuation spectra indicate
various relaxation processes and at least two conductivity regimes of transport mechanisms were
observed. Both the acoustic and electrical measured data were analyzed using suitable model
representations.
Formation and Passive Q-Switch Performance of Glass-Ceramics Containing Co2+-Doped Spinel Nanocrystals
Authors: Dymshits Olga , Shashkin Alexander , Zhilin Alexander A. , Volk Yury , Malyarevich Alexander , Yumashev Konstantin
Published: March 2009

Compositions and heat treatment conditions were determined at which absorption and
luminescence properties of aluminosilicate transparent glass-ceramics are defined mainly by
tetrahedrally coordinated Co2+ ions located in spinel nanocrystals. Optical properties of cobaltdoped
aluminosilicate transparent glass-ceramics have been studied in visible – near infrared (IR)
spectral range. It was demonstrated that the concentration of tetrahedrally coordinated Co2+ ions in
the spinel nanocrystals is determined by the CoO content in the initial glass and is independent of
the heat-treatment schedule. Absorption saturation and bleaching relaxation under excitation of the
4A2→4T1(4F) transition of tetrahedrally coordinated Co2+ ions were studied. The value of groundstate
and excited state absorption cross-sections of tetrahedrally coordinated Co2+ ions was
estimated. Comparative study of output pulse parameters of Q-switched Er:glass laser using cobaltdoped
glass-ceramics and Co2+:MgAl2O4 single crystal is presented.
Joining by Compression and Expansion of (None-) Reinforced Profiles
Authors: Marré Michael , Brosius Alexander , Tekkaya A. Erman
Published: March 2009

One major objective of the Collaborative Research Center SFB/TR10 is the flexible and
competitive production of frame structures which meet the requirements of lightweight design. The
development of composite extrusion by embedding continuous reinforcing elements, like e.g. steel
wires, in profiles during the extrusion process illustrates one approach to fulfill these conditions. To
assemble such composite profiles, joining processes and strategies have to be developed taking into
account the special composite material characteristics. In addition, the flexible production of lightweight
frame structures in small quantities generates more requirements on the joining technology.
The feasibility of joining by forming has been carried out investigating experimentally both conventionally
extruded and reinforced profiles. Therefore, joining profiles to lightweight frame structures
by both expansion and compression has been examined. The necessary forming pressure for the
joining by forming processes was applied to tubular workpieces by a medium (hydroforming) and
by a magnetic field (electromagnetic compression). Joints have been manufactured by these two
processes to transmit axial loads either by force- or form-fit.
Experimental Investigation and Elastic-Plastic Analysis on Connection Strength of Zirconium Tube-Tubesheet Joints
Authors: Yuan Biao , Wang Y.Z. , Ma X. , Zheng Yang Yan , Tu Shan Tung
Published: March 2009

Zirconium tube is widely used in heat exchanger equipments in petrochemical process for
significant corrosion resistance. The connection joint of tube-tubesheet is the weakest parts in a heat
exchanger. The experiment and numerical analysis of different materials (zirconium tubes, titanium
tubes and 16MnR tubesheets, 316L tubesheet) joints were performed in this paper. The expansion
joints specimens were prepared at the pressure ranging from 28MPa to 38MPa. And pulling out test
was performed from 20°C to 300°C. The finite element model of tube-tubesheet joint was
established. The effect of expansion pressure, temperature and groove on the pulling out strength of
joints was analyzed. Both the experiments and the finite element analysis show that the pull-out
strength increases with the increasing expansion pressures. Working temperature also has a great
effect on the connection strength of tube-to-tubesheet joints, especially for the zirconium and 316L
joints, which have the most significant difference of thermal expansion coefficient between tube and
tubesheet. The residual contacting pressure on the contact surface between tubes and the tubesheet is
not uniformly distributed and two tightness bands are found near the surfaces of the tubesheet or at
the two brinks of the groove on the tubesheet hole. Compared with the ungrooved joint, the residual
contacting pressure on the tightness bands for the grooved joint is much higher, indicating a grooved
joint has better tightness.
Blending of Natural Fibres and Thermoplastics by Screwless Extrusion
Authors: Jayaraman Krishnan , Halliwell Rex
Published: March 2009

Natural fibres, such as sisal, flax and woodfibres, are relatively inexpensive and originate
from renewable resources. Thermoplastic polymers, such as polypropylene (PP), high density
polyethylene (HDPE) and waste plastics, possess shorter manufacturing cycle times and
reprocessability. Natural fibre-reinforced thermoplastic composite materials exhibit favourable
values of modulus and strength when the fibres are properly compounded with the polymers.
Common methods for manufacturing natural fibre-reinforced thermoplastic composites, injection
moulding and extrusion, require pre-compounding of the fibres and the thermoplastic due to the
large difference in densities of the loose fibres and thermoplastic materials. Development and
analysis of a screwless extruder that employs a reliable and low technology process for melt
blending natural fibres and thermoplastic polymers is the main objective of this study.
Homogenization, Numerical Analysis & Optimal Design of MR Fluids
Authors: Muc Aleksander , Barski Marek
Published: March 2009

Usually magnetorheological fluids are dispersions of micronic magnetic particles in a
carrier liquid. We shall present the basic phenomena related to the numerical description of
homogenization for such type of composite structures. Our attention is mainly focused on the
prediction of the effective permeabilities that can play a fundamental role in the aggregation of
magnetic particles and are responsible for the gelation of the suspension and will allow the
suspension to flow. We shall also give some information on the optimal design of the effective
permeabilities taking into account the shape of magnetic particles.
Date Palm Tree Fiber as Polymeric Matrix Reinforcement, DPF-Polypropylene Composite Characterization
Authors: Alawar Ahmad , Hamed Ahmed M. , Al-Kaabi Khalifa
Published: March 2009

Recently, the interest has increased to recycle things after use. In addition, the pressure of
the environment defence organizations has increased in the same direction. Accordingly, the
composite industry has begun investigating the possibility of increasing the proportion of recycled
or biodegradable composites. This leaded to search about environment eco-friendly reinforcement
and resins systems while providing the same performance as their man made counterparts. Natural
fibers offer the possibility to play the role of the reinforcing material. In this study, we mix the 25%
untreated date palm tree fibers with 75% polypropylene using double screw extruder. Comparison
between plane polypropylene and 25 % raw date palm fiber was done. Tensile test and water
absorption test were done upon plain polypropylene and 25% raw date palm fiber specimens.
Tensile strength of reinforced polypropylene was about 20% lower than plain polypropylene. In the
other hand, modulus of elasticity of composite showed an increase of about 30% compared to plane
polypropylene. Water absorption was less sound in deterioration of the composite.
Miscibility Behaviour of Polyethylene Oxide/Hydroxypropyl Methyl Cellulose Blends
Authors: Swamy T.M. Mruthyunjaya , Siddaramaiah  , Lee Joong Hee
Published: March 2009

A series of aqueous solutions of blends based on polyethylene oxide (PEO) and
hydroxypropyl methyl celloulose (HPMC) were prepared. The solution of the blends thus obtained
was analyzed for miscibility. The effects of compositions of blends and temperature (30 and 500C)
on miscibility have been reported. The Huggin plots deviate from linearity according to the degree
of compatibility of PEO/HPMC blends at entire concentration range. Interaction parameters have
been evaluated for all blends to probe the miscibility. The blends were also characterized by
sophisticated techniques such as FTIR, DSC, TGA and SEM.
Analysis of the Novel Strain Responsive Actuators of Silicone Dielectric Elastomer
Authors: Liu Li Wu , Fan Jiu Ming , Zhang Zhen , Shi Liang , Liu Yan Ju , Leng Jin Song
Published: March 2009

The acrylic acid and silicone are common dielectric elastomer materials. These actuators
have shown excellent activate properties including large strains up to 380% and high energy densities
up to 3.4 J/g, high efficiency, high responsive speed , good reliability and durability, etc. When a
voltage is applied on the compliant electrodes of the dielectric elastomers, the polymer shrinks along
with the electric field and expands in the plain area which erects the orientation of the line. In this
paper, we synthesize a novel silicone dielectric elastomer with high dielectric constant, large strain
and high force output. Pre-strain and certain driving electric field are applied on the novel silicone
film, respectively. The strain responsing to the Maxwell stress is measured. Using the large
deformation theory of finite element method to simulate the deformable behavior of materials, the
simulation results agree with the experiment. The coupling effect of the mechanics and electric fields
applied on the electrode of the dielectric elastomers is inverstigated. The finite element simulation of
large deformation theory can be used to describe the dielectric elastomers materials large deformation
that induced by the static electric field.
Superdeep Penetration as the New Physical Tool for Creation of Composite Materials
Authors: Usherenko Sergey , Figovsky Oleg
Published: March 2009

Search of new physical tools for change of structure and properties in volume of a solid
body an actual problem is. A composite material at which the chemical compound is constant on all
volume, it is possible to make. Reinforcing devices in this material are the structures differing from
matrix material on micro- and nano levels. If little-studied phenomenon - the superdeep penetration
to use as the physical tool much factorial action in volume of a matrix material is implemented.
Thus the design of a specific composite material and unusual properties can be received.
Impact Behavior of Cracked Plate Repaired with Composite and FML Patches
Authors: Sadeghinia Mehdi , Khalili Seyyed Mohammad Reza , Ghadjar R.
Published: March 2009

In this paper, the impact behavior of repaired cracked plates was investigated
experimentally. single edge cracked aluminum plate having crack length to width ratios of 0.1, 0.3
and 0.5 was repaired with four different patch configurations namely: 3 layer GRP, 5 layer GRP
patch, 2/1 FML patch and 3/2 FML patches tested in Charpy impact and the energy absorbed by
specimens were compared together and compared with the unrepaired cracked plate. FML patches
were made of thin layers of glass/epoxy composites of 0.2 mm thickness with phosphor bronze
sheets of 0.2 mm thickness. The patching was single side. The composite and FML patching was
more effective in repairing the specimens with greater crack length. Placing 3 GRP and 5 GRP
patches increased the absorbed energy by only 3 to 4 joules respectively as compared to unrepaired
plate. The use of 2/1 and 3/2 FML patches could increase the absorbed energy two to four times
depend on crack length.
Imaging Laminar Damage in Plates Using Lamb Wave Beamforming
Authors: Veidt Martin , Ng C.T. , Hames S. , Wattinger Thomas
Published: March 2009

This paper presents the application of Lamb waves to detect and locate laminar damages
using a beam forming imaging methodology. Beam forming is using a network of transducers that are
used to sequentially scan the structure before and after the presence of damage by transmitting and
receiving guided wave pulses. An image of the damage is reconstructed by analysing the cross
correlation of the scatter signal with the excitation pulse and enables the detection and location of
potential damage areas. The results of simulation and experimental studies show that the method
enables the reliable detection of structural damages with locating inaccuracies in the order of a few
millimeters within inspection areas of 300 x 300 mm2 using a transducer network of only four
transducer elements.
Preparation and Characterization of Polyurethane/Multi-Walled Carbon Nanotubes Composites with Multi Functional Performance
Authors: Jiang Feng Dan , Hu Guo Hua , Zhang Li Qun
Published: March 2009

A melt blending process was employed to prepare nano-composites based on
thermoplastic polyurethane (TPU) and multi-walled carbon nanotubes (MWNT). The content of
MWNT filled in TPU was increased till 40phr (parts per hundreds of rubber). Scanning electron
microscope (SEM) and transmission electron microscope (TEM) showed that the unmodified
MWNT were dispersed uniformly in the TPU matrix beyond expectation. Dynamic mechanical
thermal analysis (DMTA) test demonstrated that the nano-composites possessed greatly increased
modulus, and the flowing temperature moved to higher temperature with increasing MWNT content.
Moreover, the nano-composites exhibited improved wear resistance, evidently increased thermal
conductivity, and prominently raised electrical conductivity that might mean the TPU/MWNT
nano-composites have potential application as multi-functional materials.
Intermartensitic Transformations in Ni-Mn-Ga Alloys: A General View
Authors: Seguí Concepcio , Cesari Eduard , Pons Jaume
Published: March 2009

Off-stoichiometric Ni2MnGa ferromagnetic shape memory alloys undergo a martensitic
transformation (MT) from the L21 cubic phase to a martensitic crystal lattice consisting, in the
majority of cases, of a periodic stacking sequence of nearly closed-packed planes with periodicity
of 5, 7 or 2 planes, denoted as 10M (five layered tetragonal), 14M (seven layered orthorhombic) and
2M (non-modulated tetragonal).
In addition to the parent to martensite transformation, Ni-Mn-Ga alloys tend to show stress or
temperature induced intermartensitic transformations (IMTs) towards the most stable 2M phase,
through the sequences 10M→14M→2M or 14M→2M depending on the first formed martensite.
The IMTs reported in the literature show a variety of characteristics such as reversibility,
completeness, hysteresis and temperature of occurrence, but, as a general trend, the role of internal
stresses in favouring the occurrence of IMTs is recognised.
Recently it has been shown that the L21 order degree favours the occurrence of the
intermartensitic transformation from 14M to 2M martensite, stabilising the non modulated
martensite through a decrease of its free energy with respect to the layered martensite. From this
point of view, the occurrence of intermartensitic transformations in Ni-Mn-Ga alloys appears as a
“chemical“ free energy effect. Aiming to go deeply into this aspect, in this work the occurrence of
IMTs and their properties have been examined for an extensive set of off-stoichiometric Ni2MnGa.
The results show the existence of a relationship between the IMTs temperatures and the alloys
composition, as well as the dependence of all observed IMTs (i.e., 10M→14M, 14M→2M and their
corresponding reverse transformations) on the L21 order degree.
Numerical Study of the Effect of Tool Wear on Burr Formation in Blanking Process
Authors: Zhang Juan
Published: March 2009

Numerical simulation of the blanking process of a sheet metal, i.e. the formation of
roll-over and a burnished surface, and crack initiation and propagation, is done using an elastic plastic
finite element model. The Normalized Cockcroft and Latham’s expression is used as a ductile fracture
criterion. Numerical study was conducted to investigate how the tool-wear affects the burr height by
varying the punch nose radius. The simulation results obtained under the effect of the same process
variables are in good agreement with the experimental results. Six punches with various nose edges,
0.00mm, 0.05mm, 0.10mm, 0.20mm, 0.30mm and 0.40mm were used for blanking simulations. The
results indicate that the burr height is directly proportional to the punch nose radius.
Induced Internal Bubble Shapes Affected Piezoelectric Behaviors of PVDF Films
Authors: Suwansumpan Ditthapun , Manuspiya H. , Laoratanakul Pitak , Bhalla A.S.
Published: March 2009

Poly (vinylidene fluoride), Piezoelectric, Dielectric constant, Microporous PVDF films, Bubble shapes.
Effects of Starting Materials on Molten Salt Synthesis of Bi4Ti3O12
Authors: Setasuwon Paisan , Kijamnajsak S.
Published: March 2009

Na0.5Bi0.5TiO3 is one of the potential candidates for non-lead piezoelectric materials to replace existing lead-based ones. Properties of BNT could be enhanced by reactive templated grain growth (RTGG) technique through induction of grain orientation with crystals of Bi4Ti3O12. Controlling the size of Bi4Ti3O12 crystals during the synthesis with molten salt is a major factor in optimizing RTGG. It was found that molten salt synthesis of Bi4Ti3O12 crystals with NaCl-KCl yielded larger particles, compared with Na2SO4-3K2SO4. Varying the proportion of chloride salt did not produce noticeable changes in crystal size. Bi4Ti3O12 crystals were significantly affected by raw materials treatment. Non-milling of starting powders could approximately double the crystal size
Effect of Direct Electric Resistance Heat Treatment on Mechanical Properties of NiTi Orthodontic Arch Wires
Authors: Kiattiwongse W. , Khantachawana Anak , Santiwong P.
Published: March 2009

Two types of rectangular orthodontic archwires; NiTiTM and 40oCuNiTi, were heat treated by Direct Electric Resistance Heat Treatment (DERHT) using different electric currents for 4 s. Their mechanical properties were then evaluated by micro hardness and three-point bending tests. After applying 4.5-5.5 A current, the hardness of NiTiTM increased with the increased current, whereas the change in hardness of 40oCuNiTi was slight. When 6 A current was applied, the hardness of the midspan of both wires significantly decreased. From the three-point bending test, unloading forces of NiTiTM increased after treating with 5.5 A current, while those of 40oCuNiTi decreased. However, both specimens lost their superelasticity when applied with 6 A current. In conclusion, after DERHT, various changes in mechanical properties can be noted in the different types of nickel titanium archwire.
Mechanochemical Treated Multi-Walled Carbon Nanotubes for Incorporation of Metal Ions
Authors: Rinzin U. , Singjai Pisith , Wilairat P. , Meejoo S.
Published: March 2009

Ni catalyst was removed from as received multi-walled Carbon Nanotubes (MWNTs) by acid treatment. Then, the nanotubes were treated with 4M HCl during a ball milling processing yielding mechanochemical treated MWNTs (mech-MWNTs). TEM micrographs indicate that the mech-MWNTs were still of a tubular form but with much shorter length. The equilibrium adsorption of metal ions, e.g Cu2+ and Ni2+, on the mech-MWNTs was investigated at room temperature. The adsorption isotherms gave excellent consistence with the Langmuir theory and the best fit values of K-1 and Κmax can be evaluated using non-linear least-squares. As results, the maximum of Cu2+ and Ni2+ ions uptake on to the mech-MWNTs are 0.93 ± 0.004 mg/g and 2.11 ± 0.01 mg/g respectively. There is no evidence indicating that the pore structure and layer surfaces at both ends of the mech-MWNTs are appropriate sites for metal ions adsorption.
Oily Soil Detergency under Microemulsion Conditions: Effects of Oil Loading and Surfactant Adsorption
Authors: Kaewpukpa R. , Chavadej Sumaeth , Scamehorn J.F.
Published: March 2009

Detergency process of oily soil removal from fabrics is of interest and the mechanisms of oily soil removal are very complicated involving several factors: interfacial tension, oil loading and surfactant adsorption. In this study, the effects of oil loading and the surfactant adsorption on the detergency performance of oily soil removal were investigated. Mixed surfactant systems of branched alcohol propoxylate sulfate sodium salt (Alfoterra 145-3PO), an extended anionic surfactant, and secondary alcohol ethoxylate (Tergitol 15-S-5), a nonionic surfactant, were used to form microemulsions with motor oil. The CMC and CµC values of the mixed surfactants were 0.015 and 0.04 % total active mixed surfactants concentration, respectively. A polyester/cotton blend [65/35] was selected to use as a testing fabric in detergency experiments. The results showed that the oil loading and fabric weight did not affect the efficiency of oil removal. Furthermore, with the selected formulation (0.1 wt.% Alfoterra 145-3PO and 5 wt.% Tergitol 15-S-5), the oil detachment time was investigated at different temperatures (30-50°C) and different total surfactant concentrations (0.04-0.5 %). The results showed that increasing temperature and surfactant concentration were found to decrease the oil detachment time, leading to increasing oil removal.
Preparation and Characterization of Surface Modification of Sphalerite Concentrate with Sodium Lignosulfonate
Authors: Peng Peng , Ke Jia Xiong , Zhang Liang Hua , Fu Ping Feng , Liu Xiao Hua
Published: March 2009

In order to prevent sphalerite particles from coming together in leaching solution, and to reduce the loss of organic solvent, the surface modification of sphalerite concentrate with sodium lignosulfonate was investigated. The modified sphalerite concentrate particles were characterized by dispersion experiments, determination of adsorption rate of oil, determination of contact angle, FT-IR spectra and X-ray photoelectron spectra. The results showed that the modified sphalerite concentrate particles exhibited good dispersibility in water. The sedimentation volume reduced from 0.85 ml•g-1 to 0.61 ml•g-1. The adsorption rate of oil reduced from 0.15 ml•g-1 to 0.06 ml•g-1. The contact angle between sphalerite concentrate particles and water changed from 86.9˚ before modification to 32.7˚ after modification with sodium lignosulfonate. The checking results of FT-IR and XPS spectra indicated that some modification regents were coated on the particle surface. The modifier combined to sphalerite concentrate particle surface through the chemical bond, resulting in the comprehensive stability action of static and steric effect.
Synthesis and Analysis of the Thermal Behavior of SiC-Fibre Reinforced Copper Matrix Composites as Heat Sink Material
Authors: Paffenholz Verena , Lindig Stefan , Brendel Annegret , Bolt Harald
Published: March 2009

Copper matrix composites reinforced with silicon carbide fibres (SiCf/Cu) are considered as heat sink materials for the divertor of DEMO as they combine high thermal conductivity and good mechanical strength at high temperature. A new method was developed to synthesise a metal matrix composite (MMC) consisting of about 3-6 unidirectional reinforced layers (UD-layers). The UD-layers were prepared by two subsequent electroplating processes which allow to adjust various fibre volume fractions. These single UD layers were stacked with different relative fibre orientations (0°/0° and 0°/90°) and consolidated by vacuum hot pressing to form the MMC specimen. The thermal conductivity perpendicular to fibre direction was obtained by laser flash apparatus (LFA) measurements. It is about 310 Wm-1K-1 for electroplated copper (Cu) and above 200 Wm-1K-1 for MMC specimens with a fibre volume fraction of 8-13%. Due to the manufacturing process, boundaries within the matrix were found resulting in a reduction of the values. In addition, DSC (differential scanning calorimetry) measurements were performed which gave similar results.
The Effects of Different Architectures on Thermal Fatigue in Particle Reinforced MMC for Heat Sink Applications
Authors: Schöbel Michael , Fiedler G. , Degischer Hans Peter , Altendorfer W. , Vaucher Sebastien
Published: March 2009

Particle reinforced metal matrix composites are developed for heat sink applications. For power electronic devices like IGBT modules (Insulated Gate Bipolar Transistor) a baseplate material with high thermal conductivity combined with a low coefficient of thermal expansion is needed. Commonly AlSiC MMC are used with a high volume content of SiC particles (~ 70 vol.%). To improve the performance of these electronic modules particle reinforced materials with a higher thermal conductivity are developed for an advanced thermal management. For this purpose highly conducting diamond particles (TC ~ 1000 W/mK) are embedded in an Al matrix. These new diamond reinforced MMC were investigated concerning their thermal fatigue mechanisms compared to the common AlSiC MMC. Differences in reinforcement architecture and their effects on thermal fatigue damage were studied by in situ synchrotron tomography during thermal cycling.
Two-Scale Finite Element Modelling of Microstructures
Authors: Brocks Wolfgang , Cornec Alfred , Steglich Dirk
Published: March 2009

Modelling the constitutive behaviour of metallic materials based on their microstructural features and the micromechanical mechanisms in the framework of continuum mechanics is addressed. Deformation at the lengthscale of grains is described by crystal plasticity. The macroscopic behaviour is obtained either by a homogenisation process yielding phenomenological equations or by a submodel technique. The modelling processes for two light-weight materials, namely magnesium and titanium aluminides are presented.
Surface Modification and Deuterium Retention in Tungsten and Molybdenum Exposed to Low-Energy, High Flux Deuterium Plasmas
Authors: Alimov Vladimir K. , Shu Wataru M. , Roth J. , Komarov D.A. , Lindig Stefan , Isobe Kanetsugu , Nakamura Hirofumi , Yamanishi Toshihiko
Published: March 2009

Deuterium retention in single crystal and polycrystalline tungsten and molybdenum exposed to low-energy (38200 eV/D), high ion flux (10211022 D/m2s) deuterium plasmas at various temperatures were examined with the D(3He,p)4He nuclear reaction at a 3He energy varied from 0.69 to 4.0 MeV, and with thermal desorption spectroscopy. The surface morphology was examined by scanning electron microscope. Blisters formed on the Mo surfaces under plasma exposure are significantly larger in size than those for W. The D retention in the W and Mo samples increases with the exposure temperature, reaching its maximum at about 500 and 530 K (for ion fluxes of 1021 and 1022 D/m2/s), respectively, and then decreases as the temperature grows further. For polycrystalline W and Mo exposed at temperatures above 400 K, the D retention in the bulk (far beyond the ion implanted zone) is dominant. Plastic deformation caused by deuterium super-saturation within the near-surface layer is suggested as a mechanism for blister formation and creation of defects responsible for deuterium trapping at depths up to several micrometers.
TiC Reinforced Steel Matrix Composite Layers Produced by Laser Surface Alloying
Authors: Fernández-Vicente A. , Castro Regal Gemma , Arias J.L. , Montealegre Maria Angeles
Published: March 2009

In the present work, laser surface alloying of H13 tool steel by using TiC has been performed by means of DHPDL (Direct high power diode laser). Different layers were produced by varying laser beam power and powder feeding rate. Several alloying degrees were obtained depending on the laser parameters employed. Laser surface alloyed layers were analyzed by using optical and scanning electron microscopy. Wear resistance was evaluated through pin-on-disk tests at room temperature. In general, it was observed that dilution of TiC powders into the molten H13 substrate decreased as the powder-feeding rate increased and particles size of the titanium carbide precipitates was larger for the higher feeding rates. Wear measurements showed lower values for the wear resistance coefficient of laser alloying layers produced at higher values of the powder injection (feeding) rate. Analysis of the wear surface track was conducted and the specific contribution of the microstructural features on the wear coefficient was assessed. Thus, it was found that larger particles sizes and particle contents protected the martensitic and dendritic steel matrix from being deeply worn. Lower TiC contents in the alloyed layer gave rise to a higher contribution of the plastic deformation in the wear track.
Investigation of the Possibility of Application of Boron Clusters in Composite Materials with Metal Matrix
Authors: Popov Vladimir A. , Zhizhin K.Y. , Kuznetsov N.T. , Staudhammer K.P. , Retivov V.M.
Published: March 2009

The main results of the investigation of boron-containing compounds that are planed
to use as light components for creation of metal-matrix composites (MMC) are presented in the
paper. A number of new general procedures have been developed, physical-chemical properties
of boron cluster anions BnHn
2- (n = 10, 12) were investigated. Method of MMC fabrication is
based on mechanical alloying and following compaction.
Process Characteristics of Laser Brazing Aluminium Alloys
Authors: Klocke Fritz , Castell-Codesal A. , Donst D.
Published: March 2009

Compared to welding, laser brazing offers a suitable possibility to lower the working
temperature and to join unweldable material combinations, while maintaining the numerous advantages of the laser joining process. Beside an acceptable joint strength, the brazed joints are characterised by a smooth surface and seams with almost no pores. As a result of this laser brazing combines the advantages of conventional brazing and laser welding. Within the scope of this paper the laser brazing process and its characteristics are explained in detail. In particular the interrelation of temperature progress, available processing time for brazing/diffusion and the thickness of the diffusion layer is discussed. Subsequently the material
specific particularities of laser brazing aluminium alloys are described and discussed with respect to recently gained results.
Numerical-Stochastic Modeling and Simulation of Deep Drawing Tinplate Rings
Authors: Barisic Branimir , Pepelnjak Tomaz , Kuzman Karl
Published: March 2009

Deep drawing process, although deceptively simple, involves a complex interplay
between material properties, die geometry, process variables and also friction (lubrication) conditions. Numerical and stochastic modeling and simulation of this process means defining the correlation among the variables of the process in order to improve the existing processes. Using the Box-Wilson¢s multi factorial experimental design the stochastic, numerical and experimental investigations on the thinwalled tinplate rings (material: TS 260, TS 275, TH 415, TH 435, TH 520
according to the European Standard EN 10202) were performed. The FEM analysis applying ABAQUS Explicit code as well as stochastic analysis have been used in order to predict the influences of wall thickness and lubrication on reducing drawing force and estimate its influence on process consumed energy. The accuracy of the numerical and stochastic results is confirmed through the comparison with the experimental results.
Force Measurements for Single Point Incremental Forming: An Experimental Study
Authors: Duflou Joost R. , Szekeres Alexander , Vanherck P.
Published: March 2009

In this paper an experimental platform capable of measuring forces in process during an incremental forming procedure is described and the results garnered from it are presented. Some of the earliest measurements of forces in incremental forming and the changes induced on the measured load are reported. Using a table type force dynamometer with incremental forming fixture mounted on top, three components of force were measured throughout the forming process. They were found to vary as the parts were made. The reported experimental test program was focused on
the influence of three different process parameters on the forming forces: the vertical step size between consecutive contours, the diameter of the tool and the steepness of the part’s wall. For the tested material, analytical results demonstrating the relationship between the respective process parameters and the induced forces are presented in this paper.
A New Robot-Based Sheet Metal Forming Process
Authors: Meier Horst , Dewald O. , Zhang Jian
Published: March 2009

This paper describes a new sheet metal forming process for the production of sheet metal components for limited-lot productions and prototypes. The kinematic based generation of the shape is implemented by means of a new forming machine comprising of two industrial robots. Compared to conventional sheet metal forming machines this newly developed sheet metal forming process offers a high geometrical form flexibility and also shows comparatively small deformation forces
for high deformation degrees. The principle of the procedure is based on flexible shaping by means of a freely programmable path-synchronous movement of the two robots. The sheet metal components manufactured in first attempts are simple geometries like truncated pyramids and cones as well as spherical cups. Among other things the forming results could be improved by an adjustment of the movement strategy, a variation of individual process parameters and geometric modifications of the tools. Apart from a measurement of the form deviations of the sheet metal with
a Coordinate Measurement Machine rasterised and deformed sheet metals were used for deformation analyses. In order to be able to use the potential of this process, a goal-oriented process design is as necessary as specific process knowledge. In order to achieve process stability and safety the essential process parameters and the process boundaries have to be determined.
FE Simulation of Laser Assisted Bending
Authors: Pitz M. , Merklein Marion
Published: March 2009

Steel has a long tradition and is used in nearly every application. In order to be able to compete with other lightweight materials over and over again new steel grades are developed. Interesting steel grades, which are especially suitable for the lightweight construction in the automotive industry, are the multi-phase steels. Multi-phase steels reach already yield strengths over 1000 MPa. This is a challenge for the production engineering. Drawing, forming and cutting tools must be stiff and hard and/or coated, lubricants have to decrease friction to avoid damages induced by the high surface pressures. The designers have to consider the small forming capability by large radii or reduced drawing depths. To overcome these disadvantages new, innovative forming processes, e.g. laser assisted bending or roll forming, have to be developed. In the forming technique it is known that the forming limits can be increased by warm forming. But the conventional heating systems may cause unwanted changes of the material regarding to the structure and the mechanical properties. In the case of multi-phase steels e.g. the hard phases martensite and
bainit can be transformed into ferrite and therefore the yield stresses can be changed clearly. In contrast to this laser assisted bending minimizes structural changes due to the local heating of the forming area. Beside the advantage, that only a small area of the bending part is exposed with a thermal load, the heating up with the laser permits high heating rates and also a controlling of the heating and cooling rates, so that the heating and cooling can be adapted to the material and its properties. In the context of this paper parameter studies with FE simulations of the laser assisted bending process are presented.
Methods for Monitoring of Laser Cutting by Means of Acoustic and Photodiode Sensors
Authors: De Keuster Johan , Duflou Joost R. , Kruth Jean Pierre
Published: March 2009

Laser cutting is a well-established sheet metal processing method. Nowadays a trend towards the cutting of thick plates (> 15 mm) can be observed. However for these thick plates the process window in which good cutting results can be obtained is more narrow compared to that for thin sheets due to the very difficult balance to be found between the different process parameters. Even after determination of the process window, a good cutting quality cannot always be guaranteed. Therefore cutting of thick plates is still characterized by a large scrap percentage, which impedes a breakthrough to large scale industrial use. A solution to this problem is to incorporate a sensor system in the laser cutting machine that monitors the cut quality on-line. This monitoring system could then be integrated in a process control system, which adapts the process parameters in function of the observed cut quality in real time. In this way a good cut quality could always be guaranteed. In this study, the first step in this direction, the determination of an appropriate monitoring system, is dealt with. The applicability for monitoring purposes of two types of sensors is investigated: a microphone and a photodiode. For both types, correlation between the sensor output and the cut quality is investigated in a qualitative way. The scope of the reported research was not limited to contour cutting, also piercing is covered in the study.
Tribology in Sheet Metal Forming with Regard to Challenges in Lightweight Construction
Authors: Groche Peter , Callies T.
Published: March 2009

Today’s sheet metal forming is affected by several trends concerning sheet metal
material. The sheet metal forming industry is thereby influenced by the reinforced demand of drawn components made of high strength steels, aluminum or magnesium because of economical and ecological reasons. Besides shifted mechanical properties, changing the sheet metal material influences the entire tribological system and therefore raises questions concerning the suitability of the tool material as well as the lubrication.
Towards Multi-Classification of Human Motions Using Micro IMU and SVM Training Process
Authors: Shi Guang Yi , Zou Yue Xian , Li Wen J. , Jin Yu Feng , Guan Pei
Published: March 2009

This paper introduces a novel approach for human motion recognition via motion feature vectors collected by A Micro Inertial Measurement Unit (µIMU). First, µIMU that is 56x23x15mm3 in size was built. The unit consists of three dimensional MEMS accelerometers, gyroscopes, a Bluetooth module and a Micro Controller Unit (MCU), which can transmit human motion information through a serial port to a computer. Second, a human motion database was setup by recording the motion data from the µIMU. The motions include fall, walk, stand, run and step upstairs. Third, Support Vector Machine (SVM) training process was used for human motion multi-classification. FFT was used for feature generation and optimal parameter searching process was done for the best SVM kernel function. Experimental results showed that for the given 5 different motions, the total correct recognition rate is 92%, of which the fall motion can be classified from others with 100% recognition rate.
Inducing Layer Dependence of BiFeO3 Based Multilayer Capacitors
Authors: Luo Ya Feng , Xie Dan , Zang Yong Yuan , Song Rui , Ren Tian Ling , Liu Li Tian
Published: March 2009

Multifunctional BiFeO3 (BFO) thin films were deposited on Bi3.15Nd0.85Ti3O12 (BNdT)/Pt and Pb(Zr1−x,Tix)O3 (PZT)/Pt substrates respectively by sol-gel process. The ferroelectric properties were studied for Metal-Ferroelectric-Mental (MFM) capacitors. The MFM structure exhibited well clockwise capacitance-voltage hysteresis loops due to the ferroelectric polarization of multilayer thin films achieved. The remnant polarization (2Pr) of the BFO/PZT and BFO/PZT multilayer capacitors were 45.1μC/cm2 and 23.2μC/cm2, respectively at the applied voltage of 8V. The leakage current of Pt/BFO/BNdT/Pt is about 3×10-5A/㎝2 at applied voltage of 4V, one order smaller than Pt/BFO/PZT/Pt capacitor. For the BFO/BNdT/Pt, it exhibited a weak saturated ferromagnetic response at room temperature and the multilayer was anti-ferromagnetic. However, for the BFO/PZT/Pt, well-developed M-H loops together with remnant magnetizations can be observed in at room temperature. The highest saturation magnetizations (Ms) of both capacitors were measured to be 2.47emu/cm3.
Investigation of Thermal Bonding on PMMA Capillary Electrophoresis Chip
Authors: Zhang Hai Feng , Liu Xiao Wei , Peng Zhi Cheng , Wang Wei , Chen Yu Feng
Published: March 2009

PMMA, Capillary Electrophoresis, Thermal bonding, Factor, Deformation.
Abstract. In this paper, using the powder hot embossing machine, the effects of the bonding temperature, pressure and time on the deformation of microchannel dimensions is studied systematically. The bonding temperature is mainly influence factor on the deformation of microchannel determined by the method of orthogonal experiment. Some mathematical models are described to optimize the thermal bonding process parameters. According theory and experimental curve, the optimal experimental model (83°C, 0.4Mpa and 7 min) is suggested. Under the process parameters the deformation of crossing section dimension before and after thermal bonding is 37.8%. The channel is successfully sealed underneath with a thin foil 30μm thickness PMMA for contactless conductivity detection. The entire fabrication methodology may also be useful for preparation of other polymer microfluidic systems. Finally, the performance of the PMMA chip is demonstrated to separate continuously K+ ions using the contactless conductivity detection.
Active Finite Element Method for Simulating the Contraction Behavior of a Muscle-Tendon Complex
Authors: Tsui Chi Pong , Tang Chak Yin , Chow Chi Loong , Hui S.C. , Hong Y.L.
Published: March 2009

A three-dimensional finite element analysis was conducted to simulate the effects of the varying material parameters on the contraction behaviors of a muscle-tendon complex using an active finite element method. The material behavior of the skeletal muscle was assumed to be orthotropic and the muscle model consists of two parts: the active and the passive parts. An active finite element method was then used for accommodating both the active and passive behaviors of the muscle into the muscle model. In this active-passive muscle model, the active component is governed by an activation level, a time period, a muscle sensitivity parameter and a strain rate. The material property of the passive component was assumed to be viscoelastic and the tendon is assumed to be linear elastic. The effects of activation amplitude and viscoelastic material parameters on the active, passive and total force-length relationship of the cat muscle under isometric contraction were predicted. The predicted results were found to be close to the experimental data reported in the available literature. Hence, the active-passive muscle model was extended to simulate the stress distribution of the cat muscle subject to shortening contraction and different activation amplitude. By varying the magnitude of the material parameters, different muscle behaviors could be generated. The proposed active finite element method lays a good foundation for simulation of human musculoskeletal motion.
Zeolite Coatings on Porous Monoliths
Authors: Scheffler Michael , Scheffler Franziska
Published: March 2009

Zeolites find various applications in heterogeneous catalysis, microreactor techniques, sorption techniques, ion exchange and more recently in heat pump applications. In common processes zeolites are used as shaped bodies with a size in the millimeter range. Novel processes made it necessary to apply zeolites as coating on inert or reactive bulk or porous substrate materials. In the past fifteen years various methods for zeolite coatings have been developed and adapted to the specific requirements with respect to the process they are to be used and to the specific physical and chemical properties of the support material.
Fast Photonic Switches with Ferroelectric Films
Authors: Glebov Alexei L. , Lee Michael G. , Yokouchi Kishio
Published: March 2009

Fir st prototypes of electrooptic (EO) planar deflector switches (PDS) are fabricated with hybrid integration on Si substrates. Planar optical modules, made in silica-on-silicon technology, consist of input and output waveguide microlenses facing each other and slab waveguides in between. The modules interconnect the input and output fibers with laterally collimated light beams less than 400 m in width at distances up to 100 mm with losses lower than 3 dB. Thin lead lanthanum zirconium titanate (PLZT) films with prism-shaped electrodes grown on SrTiO3 substrates form the deflector elements. The PLZT films are more than 10 m thick with EO coefficients about 40 pm/V. The deflector assembly technology provides chip vertical positioning accuracy better than 1 m. The deflector chips are attached to the optical substrates with thermocompression flip-chip bonding. The optical power losses of the modules with test silica chips can be as low as 3.6 dB. However, the lowest module losses achieved with PLZT are about 10 dB. The channel-to-channel switching operations are demonstrated at about 40 V and switching times less than 300 ns.
Numerical Study of Grain Boundary Diffusion in Nanocrystalline Materials
Authors: Gryaznov D. , Fleig J. , Maier Joachim
Published: March 2009

Diffusion in nanocrystalline materials is becoming an increasingly important topic. The analysis of diffusion profiles obtained in nanocrystalline materials with enhanced grain boundary diffusion, however, is not straightforward since assumptions made in the deviation of the conventional models are often not fulfilled. In this contribution numerical diffusion studies are performed in order to investigate effects caused by the high density of interfaces in nanocrystalline material. A continuum model based on the 2D 2-nd Fick’s law was solved by means of the finite element method. This allows us to analyze diffusion profiles for different geometrical situations such as a single boundary, square grains with the grain size of 80 nm and 25 nm and geometries comprising differently oriented boundaries of the average length of 30 nm . The analysis was carried out for different diffusion lengths corresponding to Harrison type A and type B kinetic regimes. For the isolated boundary a very good agreement was achieved in comparison with the classical Whipple’s solution. For nanocrystalline material, however, considerable errors can occur when analyzing the averaged diffusion profiles in the conventional Harrison type A and B kinetics.
Iron Diffusion Near Surface of Fe3Si is Fast- and Decays to Bulk Values within 3 nm
Authors: Kmiec D. , Sepiol B. , Sladecek M. , Vogl G. , Korecki J. , Slezak T. , Rüffer R. , Vanormelingen K. , Vantomme A.
Published: March 2009

Nuclear resonant scattering (NRS) methods allow to determine diffusion coefficients and jump directions. The capability to measure the diffusion mechanism in ordered intermetallics on atomic scale by mean of NRS was shown in various experiments and in different geometries (transmission [1,2], Bragg [3], grazing incidence [4]). A combination of NRS and grazing incidence geometry can be used as a very sensitive tool to investigate thin films or near-surface-regions [4]. Fe3Si with a D03 structure stable at high temperature and with a well known diffusion mechanism was chosen for this investigation.