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Online since: October 2009
Authors: Munekazu Ohno, Ying Chen, Tetsuo Mohri
The resultant free energy formulae can be written as follows,
{ }( ) ( )( )
∫ ∑
∇∇⋅+
=
'
'
' dV
f
L
F
uII
IIuII
ICVM
chem
,,
,,
0
3
1
φφκφ , (1)
where L is the unit length of the coarse-grained cell, φI is the independent variable of the free energy,
which describes the atomic configuration in the system.
f0CVM is the conventional CVM free energy for the uniform system and is generally expressed as [13], ( ) ( )∑∑ ∑ ⋅ +⋅= m J m m m m B m mm CVM JxJxT�kv�f 2 0 ln γ ξ , (2) where � is the number of the lattice points, vm is the effective cluster interaction energy for a cluster m, kB is the Boltzmann constant, T is the absolute temperature, γm is a coefficient related to the symmetry of the crystal lattice and the size of the cluster considered in the formulation. ξm is the correlation function of m-body cluster, xm(J) is the cluster probability of finding the atomic configuration J on the cluster m.
(12) where � is the number of lattice points, θ is the spin flipping probability per unit time, ∆E represents the change of the internal energy in ∆t and the notation, L(x) =xlnx-x, is used in eq. (12) for convenience.
The calculated results below T* =1.7 are missing in Fig. 3, since the solutions of real numbers for L11* and L22* were not obtained below this temperature.
f0CVM is the conventional CVM free energy for the uniform system and is generally expressed as [13], ( ) ( )∑∑ ∑ ⋅ +⋅= m J m m m m B m mm CVM JxJxT�kv�f 2 0 ln γ ξ , (2) where � is the number of the lattice points, vm is the effective cluster interaction energy for a cluster m, kB is the Boltzmann constant, T is the absolute temperature, γm is a coefficient related to the symmetry of the crystal lattice and the size of the cluster considered in the formulation. ξm is the correlation function of m-body cluster, xm(J) is the cluster probability of finding the atomic configuration J on the cluster m.
(12) where � is the number of lattice points, θ is the spin flipping probability per unit time, ∆E represents the change of the internal energy in ∆t and the notation, L(x) =xlnx-x, is used in eq. (12) for convenience.
The calculated results below T* =1.7 are missing in Fig. 3, since the solutions of real numbers for L11* and L22* were not obtained below this temperature.
Online since: June 2013
Authors: Gerhard Hirt, Markus Daamen, Michele Vidoni
Due to economic viability and technological factors, the welding method is limited in the maximum number of thickness transitions.
In the case of the tailor rolled products, the number of rolling passes required for wide profiles represents the main restriction [3].
The high solidification rate achievable in this process reduces significantly the segregation problems compared to other casting methods and results in a fine-grained and homogeneous microstructure [5].
Experiment number Profile depth Δhroll Minimum casting gap - h Profile slope β [mm] [mm] [-] E1 0.15 1.5, 1.7, 2.0 1:10, 1:20 E2 0.15 1.5, 1.2, 1.0 1:10, 1:20 E3 0.25 1.7 , 2.0 1:10, 1:20 E4 0.25 1.5, 1.2, 1.0 1:10, 1:20 E5 0.5 1.5, 1.7, 1.9 1:1 Numerical model.
In the case of the tailor rolled products, the number of rolling passes required for wide profiles represents the main restriction [3].
The high solidification rate achievable in this process reduces significantly the segregation problems compared to other casting methods and results in a fine-grained and homogeneous microstructure [5].
Experiment number Profile depth Δhroll Minimum casting gap - h Profile slope β [mm] [mm] [-] E1 0.15 1.5, 1.7, 2.0 1:10, 1:20 E2 0.15 1.5, 1.2, 1.0 1:10, 1:20 E3 0.25 1.7 , 2.0 1:10, 1:20 E4 0.25 1.5, 1.2, 1.0 1:10, 1:20 E5 0.5 1.5, 1.7, 1.9 1:1 Numerical model.
Online since: April 2015
Authors: Chun Peng Wen, Rui Bo Zhang, Qi Xiu Pang
Winterwerp et al.[9], Alberle et al.[10] and Houwing[3] considered that an increase of density increased the number of bonds between the sediment particles and induced the increase of bed strength.
Table 1 Characteristics of sediment particle size Sample Content[%] Parameters of grain size sand silt clay D50[mm] Qdφ Skφ No.1 17.3 70.9 11.8 0.0377 0.78 0.22 No.2 13.1 66.4 20.5 0.0227 1.43 0.60 No.3 13.0 56.8 30.2 0.0164 1.82 0.56 Experimental instruments.
Butfor engineering practice, it is significant only when a large number of sediment is suspended to water.Therefore, in these experiments, the sediment incipient motion is defined as the sediment suspending generally and the concentration surveyed by the OBS increasing evidently.The experimental phenomena are as followed
While the clay content in the fine sediment sample is about 30.2%, and the number of bonds between the sediment particles are large which induce the increase of bed strength, resulting that it needs larger velocity of flow to lift the sediment.
Table 1 Characteristics of sediment particle size Sample Content[%] Parameters of grain size sand silt clay D50[mm] Qdφ Skφ No.1 17.3 70.9 11.8 0.0377 0.78 0.22 No.2 13.1 66.4 20.5 0.0227 1.43 0.60 No.3 13.0 56.8 30.2 0.0164 1.82 0.56 Experimental instruments.
Butfor engineering practice, it is significant only when a large number of sediment is suspended to water.Therefore, in these experiments, the sediment incipient motion is defined as the sediment suspending generally and the concentration surveyed by the OBS increasing evidently.The experimental phenomena are as followed
While the clay content in the fine sediment sample is about 30.2%, and the number of bonds between the sediment particles are large which induce the increase of bed strength, resulting that it needs larger velocity of flow to lift the sediment.
Online since: February 2019
Authors: M.Y. Elistratkin, M.V. Absimetov, V.V. Voronov, E.S. Glagolev
This is due to a relatively small number of profile enterprises even on a national scale and uneven distribution across certain regions [3, 4].
Interest to this material from private producers is well marked by the number of Internet forums devoted to this issue.
At the same time the maximum possible number of ingredients (taking into account the compatibility factor) should be added during binder preparation [13-15].
Scheme of obtaining and using composite binder for the production of non-autoclaved aerated concrete Such approach: - solves the problem of the molding mass grain composition heterogeneity, which is particularly acute when using various local natural and technogenic raw materials (e.g. screening and crushing stone rocks, ashes, slag, brick masonry cuttings, concrete structures, etc.).; - ensures the distribution uniformity and the one-time commitment of work introduced in relatively small quantities, organic and inorganic additives (lime, gypsum, etc.); - simplifies molding mixture preparation procedure, reduces the probability of quality fluctuations due to possible dosing errors; - increases the adding components activity (portland cement in particular) due to their mutual mechanochemical activation.
Interest to this material from private producers is well marked by the number of Internet forums devoted to this issue.
At the same time the maximum possible number of ingredients (taking into account the compatibility factor) should be added during binder preparation [13-15].
Scheme of obtaining and using composite binder for the production of non-autoclaved aerated concrete Such approach: - solves the problem of the molding mass grain composition heterogeneity, which is particularly acute when using various local natural and technogenic raw materials (e.g. screening and crushing stone rocks, ashes, slag, brick masonry cuttings, concrete structures, etc.).; - ensures the distribution uniformity and the one-time commitment of work introduced in relatively small quantities, organic and inorganic additives (lime, gypsum, etc.); - simplifies molding mixture preparation procedure, reduces the probability of quality fluctuations due to possible dosing errors; - increases the adding components activity (portland cement in particular) due to their mutual mechanochemical activation.
Online since: September 2015
Authors: Akio Kokubu, Hiroshi Tanaka, Fumiharu Ikai, Kazutaka Okumoto, Shoichi Kikuchi, Tatsuo Sakai
Thus, a number of loadings would be applied with very high frequency to tips of a couple of compressing punches.
As indicated in Fig. 6, the fatigue limit for the usual surface-initiated fracture mode is determined as σw=1050MPa and the number of stress cycles at the knee point of the corresponding S-N curve is given as Nw=3.782×105 by applying the JSMS standard [7].
F=99% F=90% F=50% F=10% F=1% Number of cycles to failure Nf Stress amplitude σa (MPa) ○ Fatigue data in usual fracture ● Fatigue data in VHCF region ◇ Specimens measured residual stress Fig. 8 P-S-N curves for mechanically finished specimens Fractography of the fracture surface.
Accordingly, the slip band at the surface grain is supposed to be origin of the fatigue crack.
Main conclusions obtained in this study are summarized as follows; 1) Fatigue limit of this steel in the conventional concept for the surface-initiated fracture was determined as =1050MPa, and the number of stress cycles at the knee point of the conventional S-N curve was given as N=3.782×105. 2) Fracture surfaces of failed specimens along the sloped portion of the conventional S-N curve were carefully observed by using a SEM.
As indicated in Fig. 6, the fatigue limit for the usual surface-initiated fracture mode is determined as σw=1050MPa and the number of stress cycles at the knee point of the corresponding S-N curve is given as Nw=3.782×105 by applying the JSMS standard [7].
F=99% F=90% F=50% F=10% F=1% Number of cycles to failure Nf Stress amplitude σa (MPa) ○ Fatigue data in usual fracture ● Fatigue data in VHCF region ◇ Specimens measured residual stress Fig. 8 P-S-N curves for mechanically finished specimens Fractography of the fracture surface.
Accordingly, the slip band at the surface grain is supposed to be origin of the fatigue crack.
Main conclusions obtained in this study are summarized as follows; 1) Fatigue limit of this steel in the conventional concept for the surface-initiated fracture was determined as =1050MPa, and the number of stress cycles at the knee point of the conventional S-N curve was given as N=3.782×105. 2) Fracture surfaces of failed specimens along the sloped portion of the conventional S-N curve were carefully observed by using a SEM.
Online since: July 2011
Authors: Zhang Luo
This seems to be appropriate as the steel fiber lengths are usually larger than the grain size of concrete (Hassan Ahmad et al., 1991[4]).
The mechanical properties of SFRC are determined by a number of factors including the elastic modulus and strengths of constituents; the aspect ratio, volume fraction, orientation and distribution of steel fibers; and the nature of the interface of steel fiber/matrix bond.
The mechanical properties of SFRC are determined by a number of factors including the elastic modulus and strengths of constituents; the aspect ratio, volume fraction, orientation and distribution of steel fibers; and the nature of the interface of steel fiber/matrix bond.
Online since: July 2011
Authors: Keishi Nishio, Koya Arai, Hiroyuki Akimoto, Tohru Kineri, Tsutomu Iida
A large number of studies have investigated the thermoelectric characteristics of Mg2Si, and the output characteristics of Mg2Si and modules have been reported by Iida and others[3,4].
The Co3O4 phase disappeared at x=1.5, and a single phase of NaCo2O4 was obtained because a small amount of Na became localized at the grain boundary or evaporated during the heat treatment in the electrical furnace.
The Co3O4 phase disappeared at x=1.5, and a single phase of NaCo2O4 was obtained because a small amount of Na became localized at the grain boundary or evaporated during the heat treatment in the electrical furnace.
Online since: May 2011
Authors: Zheng Jun Liu, Lin Zong
The microstructure of alloy A consists of lamellar martensite, retained austenite, VC particles with exploded shape and (Fe,Cr,V)7C3 complex carbides, the (Fe,Cr,V)7C3 complex carbides are distributed on the grain boundaries with a interrupted netted structure, as illustrated in.
In Fig.3c, when the Cr content is 25% , it was found that there are a number of (Fe,Cr,V)7C3 complex carbides with hexagonal shape distributed dispersely and uniformly in the matrix.
In Fig.3c, when the Cr content is 25% , it was found that there are a number of (Fe,Cr,V)7C3 complex carbides with hexagonal shape distributed dispersely and uniformly in the matrix.
Online since: June 2012
Authors: Zhi Hui Sui, Lei Zhang, Jia Song
After liming, symmetrically cutting the whole limed pelt along the ridge line, then cutting to a number of small leather pieces, weighing, and then adding different deliming materials to implement deliming experiment according to the following processes.
Measuring the content of calcium ion in the grain layer, middle layer and meat layer of the leather sample; specifically splitting the leather sample with an operating knife blade according to the method specified in 1.2.1, and respectively calculating the content of calcium ion of each layer.
Measuring the content of calcium ion in the grain layer, middle layer and meat layer of the leather sample; specifically splitting the leather sample with an operating knife blade according to the method specified in 1.2.1, and respectively calculating the content of calcium ion of each layer.
Controlled Synthesis of Mn3O4 and MnOOH by a Hydrothermal Method and Their Electrochemical Behaviors
Online since: June 2011
Authors: Zi Cheng Zhou, Sheng Tao Xing, Zi Chuan Ma, Yin Su Wu
The third vibration band, located at a weaker wave number, 410 cm-1, can be attributed to the vibration of manganese species (Mn3+) in an octahedral site [22].
The average grain size found by the intercept method ranged from 20 to 40 nm in diameter.
The average grain size found by the intercept method ranged from 20 to 40 nm in diameter.