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Online since: February 2008
Authors: Mohamad El Mehtedi, M. Simoncini, Carlo Bruni, Lorenzo Donati
Experimental procedures
The AZ31 alloy was investigated in the as-extruded condition and after an heat treatment at 500°C
for 2h in order to achieve a fully equiaxed and coarse grain structure [10].
Equivalent stresses (σ) and strains (ε) were derived from τ and γ using the von Mises criterion: (1) (2) where Γ is the torque, N the number of revolutions, p ( T,NNlogd/logd & Γ= )the work hardening rate and q ( T,NNlogd/logd &Γ= ) the revolution rate sensitivity of torque.
Equivalent stresses (σ) and strains (ε) were derived from τ and γ using the von Mises criterion: (1) (2) where Γ is the torque, N the number of revolutions, p ( T,NNlogd/logd & Γ= )the work hardening rate and q ( T,NNlogd/logd &Γ= ) the revolution rate sensitivity of torque.
Online since: August 2008
Authors: Bussarin Ksapabutr, M. Panapoy, M. Saengsil
Introduction
The growing attention has been dedicated to intrinsically conducting polymers (ICPs) during the
last decade due to their availability of a diverse range of monomer analogues, possible
modifications of basic polymer and dopant systems, and formation of film coating on various
substrates These properties may be useful in the realization of a number of devices, such as
electronic circuit components, light-emitting diodes, and sensors [1].
At higher EG concentration, the electrical conductivity decreased owing to a reduction of PEDOT/PSS concentration, which lowers the density of connections between the grains.
At higher EG concentration, the electrical conductivity decreased owing to a reduction of PEDOT/PSS concentration, which lowers the density of connections between the grains.
Online since: January 2009
Authors: Robert Panowicz, Jacek Janiszewski
Zerilli-Armstrong model for fcc metals is based on dislocation mechanics:
( )
1 2 1 2
1 2 3
exp ln
G s s T s T kd
σ σ ε ε
−
'= ∆ + − + +& ,
where ∆σ'G, s1, s2, s3, and k are the material constants and d is the average grain diameter.
Conclusions On the basis of the presented work, general conclusions may be drawn: • dynamic material behaviour for electromagnetic expansion is quite well described by the presented above electro-mechanical model; • from among the analysed constitutive models, SG and PTW equations seem to be the most appropriate for freely expanding ring test, however, SG model needs smaller number of constitutive relation parameters than PTW model and material parameters for SG equation is easier to find relatively in specialistic literature; • despite the fact that JC model gave the worse results, modifications of this simple and the most popular model by application of Gurson-Tvergaard-Needleman yield condition with the evolution of porosity as the sum of the rate of growth and rate of nucleation of voids should allow us to receive better agreement between the calculated and experimental data.
Conclusions On the basis of the presented work, general conclusions may be drawn: • dynamic material behaviour for electromagnetic expansion is quite well described by the presented above electro-mechanical model; • from among the analysed constitutive models, SG and PTW equations seem to be the most appropriate for freely expanding ring test, however, SG model needs smaller number of constitutive relation parameters than PTW model and material parameters for SG equation is easier to find relatively in specialistic literature; • despite the fact that JC model gave the worse results, modifications of this simple and the most popular model by application of Gurson-Tvergaard-Needleman yield condition with the evolution of porosity as the sum of the rate of growth and rate of nucleation of voids should allow us to receive better agreement between the calculated and experimental data.
Online since: October 2008
Authors: R.A. Ikegami, B. de M. Purquerio, C.A. Fortulan, Claudia C. Camilo, Arnaldo R. Santos
The sucrose
particles were poured and mixed into the alumina ceramic slurry and dried in hot air to obtain the
sucrose-powder grains.
Quantitatively, the results showed that cell numbers on the non coated alumina and coated alumina scaffolds were very close to the negative toxicity control, as shown in Fig.2.
Quantitatively, the results showed that cell numbers on the non coated alumina and coated alumina scaffolds were very close to the negative toxicity control, as shown in Fig.2.
Online since: July 2019
Authors: Tri Widodo Besar Riyadi, Tjipto Sujitno, Bambang Waluyo Febriantoko, Tri Tjahjono, Margono Margono, Suprapto Suprapto
However, the nitriding occurred at high temperatures and long durations can lead to the high deposition and undesirable grain growth of nitrogen atoms which could decrease both strength and corrosion resistance [1].
Thus, further increase of gas pressure can only increase the number of the ionized nitrogen atom in the Al surface, as also occur in the increased nitriding time.
Thus, further increase of gas pressure can only increase the number of the ionized nitrogen atom in the Al surface, as also occur in the increased nitriding time.
Online since: October 2006
Authors: Debora Fino, Nunzio Russo, Emanuele Cauda, Davide Mescia, Simone Solaro, Guido Saracco, Vito Specchia
Meeting the emission levels imposed for NOx and particulate matter (PM) by the legislation (Euro
IV in 2005 and, in the 2008 perspective, Euro V) requires the development of a number of critical
technologies, so as to fulfil these very stringent emission limits (e.g. 0.025 g/km for PM).
Wall-flow filters (materials: partially sintered SiC or cordierite grains; pore size: 10 μm) are very efficient (>90%) since they are based on a shallow-bed filtration mechanism, whereas foam (materials: zirconiatoughened-alumina or -mullite, SiC; pore size: 100-400 μm) and fibre filters (materials: dopedalumina; fibre size: 10 μm) are somehow less efficient as a consequence of the deep filtration mechanism they enable.
Wall-flow filters (materials: partially sintered SiC or cordierite grains; pore size: 10 μm) are very efficient (>90%) since they are based on a shallow-bed filtration mechanism, whereas foam (materials: zirconiatoughened-alumina or -mullite, SiC; pore size: 100-400 μm) and fibre filters (materials: dopedalumina; fibre size: 10 μm) are somehow less efficient as a consequence of the deep filtration mechanism they enable.
Online since: June 2007
Authors: Shou Hashiba, Michiaki Kobayashi, Setsuo Miura, Junichi Shibano, Naohiro Aoyama
Here, we
denote the slip amounts of primary slip
system in crystal i as
p
iγ& (i=1~n, n=729:
number of FEM elements), and slip amounts
of secondary slip systems crossing with the
primary slip system in the same crystal i as
s
iγ& (s=1~8); then the multiplicative amounts
Γ of intersected slides between primary and
secondary slip systems is defined as [4]
(3)
in which .avΓ is average of Γ per element.
Fig.8 Comparison of localized deformation diagram between simulated result and experimental data of A1070 with grain size 74µm Fig. 7 Example of fractal dimension changes of laser speckle pattern on Aluminum specimens under proportional strain paths References [1] M.
Fig.8 Comparison of localized deformation diagram between simulated result and experimental data of A1070 with grain size 74µm Fig. 7 Example of fractal dimension changes of laser speckle pattern on Aluminum specimens under proportional strain paths References [1] M.
Online since: June 2007
Authors: Nam Ihn Cho, Yo Seung Song, Deuk Yong Lee, Se Jong Lee
The thick films have 96% purity
of Al2O3 and 4-7 micrometers of grain size.
The number of the layer of the Cr-Si multilayer structure was 6 or 10, and thicknesses were estimated as 700 - 1200nm by an alpha step method.
The number of the layer of the Cr-Si multilayer structure was 6 or 10, and thicknesses were estimated as 700 - 1200nm by an alpha step method.
Online since: September 2009
Authors: Yu Hong Huang, Yu Gang Zhao, Xian Jin Yu, Zeng Dian Zhao
The definition of
durability, in accordance with the R10/3 of the priority number system, in the series, based on the
surface roughness value before grinding, if the decline of the surface roughness value can not
reached up to one lever, that is considered as the loss of abrasive grinding capacity [8].
He: The Analysis and Research on Sintering Preparation and Finishing Characteristic of Magnetic Abrasive Grains (M.S.
He: The Analysis and Research on Sintering Preparation and Finishing Characteristic of Magnetic Abrasive Grains (M.S.
Online since: May 2006
Authors: António Castanhola Batista, Altino Loureiro, António Rodrigues
A cellular microstructure
is displayed in the central zone of the welds done using low current, see Figs. 1a) and 1c), while
columnar grain growth is observed close the fusion line.
The technique for determination of the ferrite volume fraction by systematic point count is sensitive to the observer, but the accuracy of the estimation can be increased by increasing the number of fields counted.
The technique for determination of the ferrite volume fraction by systematic point count is sensitive to the observer, but the accuracy of the estimation can be increased by increasing the number of fields counted.