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Online since: February 2012
Authors: Ming Sen Zheng, Quan Feng Dong, Jun Zang
The average grain size of MnO is 86nm as estimated by Scherrer equation based on the (200) peak.
As the comparison, the profile of the capacity of the MnO powder vs cycle number at the current density of 1C rate is shown in Fig.5.
As the comparison, the profile of the capacity of the MnO powder vs cycle number at the current density of 1C rate is shown in Fig.5.
Online since: July 2015
Authors: Ru Feng Cen, Kun Yan Wang, Wen Wen Shu
A large number of waste polyacrylonitrile fibers were produced in the production process every year.
Finally, the resulting product was treated with grain alcohol and dried at 85℃ in a vacuum drying chamber.
Finally, the resulting product was treated with grain alcohol and dried at 85℃ in a vacuum drying chamber.
Online since: December 2011
Authors: S. Banumathy, A.K. Singh, Rajiv Kumar Mandal
A large number of components used in these applications are in plate, sheet or extruded rod forms which are produced by thermomechanical processing/treatments.
It has been observed that the final texture evolved during α→β→α transformation at the scale of a grain either during α→β transformation on heating or/and during β→α transformation during cooling.
It has been observed that the final texture evolved during α→β→α transformation at the scale of a grain either during α→β transformation on heating or/and during β→α transformation during cooling.
Online since: June 2021
Authors: Fu Qiang He, Xia Ling Liao, Hong Huang, Chang Hui Yang
With the help of SO3 adjustment in cement with DEIPA, a great number of hydro-sulfoaluminates precipitated at the early stage of hydration to decrease the porosity of hardened cement pastes, which contributed to the strength gain of cement.
The BSE image of blank sample shows the typical morphology of Portland cement (Fig. 7a), in which the inner product of C-S-H (also known as high density C-S-H) covers the surfaces of unreacted clinker grains whilst the outer product (alternatively low-density C-S-H) fills in the pores.
In addition, the inner product of C-S-H tends to disappear, being replaced by a small amount of AFm on the boundaries of clinker grains (Fig. 7b), and this is an important feature to differentiate the morphology of blank sample.
In this sample, AFm phase covering the surfaces of unreacted clinker grains is more pronounced, which is rarely reported by the existing literature and deserves further investigation.
The BSE image of blank sample shows the typical morphology of Portland cement (Fig. 7a), in which the inner product of C-S-H (also known as high density C-S-H) covers the surfaces of unreacted clinker grains whilst the outer product (alternatively low-density C-S-H) fills in the pores.
In addition, the inner product of C-S-H tends to disappear, being replaced by a small amount of AFm on the boundaries of clinker grains (Fig. 7b), and this is an important feature to differentiate the morphology of blank sample.
In this sample, AFm phase covering the surfaces of unreacted clinker grains is more pronounced, which is rarely reported by the existing literature and deserves further investigation.
Online since: April 2018
Authors: Zoran Radaković, Simon Sedmak, Sanja Petronić, Srdjan Tadić, Emina Džindo, Branislav Đorđević, Blagoj Petrovski
In order to satisfy statistical analyses, a large number of specimens were tested.
Effects of martensite-аustenite constituent (MA) and effective grain size on fracture toughness in the transition region was analyzed from the standpoint of cleavage crack initiation and propagation fracture toughness analysis in transition temperature region of API X70 pipeline steels. [1] Lower fracture toughness assessment in the transition temperature area, wherein fracture by cleaving is assumed, requires a known value of fracture stress, as well as the location of crack initiation [2].
The value of N from eq. (3), in fraction form, was rounded to the first higher number, before included in the eq. (5)
Effects of martensite-аustenite constituent (MA) and effective grain size on fracture toughness in the transition region was analyzed from the standpoint of cleavage crack initiation and propagation fracture toughness analysis in transition temperature region of API X70 pipeline steels. [1] Lower fracture toughness assessment in the transition temperature area, wherein fracture by cleaving is assumed, requires a known value of fracture stress, as well as the location of crack initiation [2].
The value of N from eq. (3), in fraction form, was rounded to the first higher number, before included in the eq. (5)
Online since: May 2011
Authors: Ying Guang Fang, Ren Guo Gu, Wei Dong Pan
Micro particles of clay possess a very large specific surface area, and a large number of charges are assembled on the particle surfaces, with the result that electric potential on the particle surface is generally in the range from tens to hundreds of mV[2].
Besides, in a thin film flow, while the film thickness is less than ten-molecule-thick layer (about 5 nm), the equivalent viscosity coefficient of polarity water will depend generally on the number of molecule layers and can be increased by 105 times[3].
Pore solutions in the samples are NaCl solutions with different molar concentration, which means the number of moles of solute dissolved in one liter of solution.
Table 1 Geotechnical Properties of the Samples Used in Tests Composition Number e0 ρd (g/cm3) w (%) Averagediameter() CEC cmol/kg Total surface area ( m2/g) Outer surface area ( m2/g) Charge density C/m2 Plasticity index Ip ( %) 1-1 1.64 0.94 67.3 2.5 73.5 456 39.8 0.1554 00% Bentonite 1-2 1.61 0.96 67.0 93.7 2-1 1.62 0.95 65.8 2-2 1.63 0.95 66.3 3-1 1.66 0.94 66.0 3-2 1.65 0.94 65.4 4-1 1.64 0.94 63.8 4-2 1.63 0.95 64.1 5-1 1.63 0.95 63.3 5-2 1.63 0.95 63.4 Table 2 Permeability Coefficient from the Seepage Consolidation Test Results Number NaCl solution concentration ni (mol) Consolidation coefficient Cv(cm2/s) permeability coefficient ka (cm/s) Average permeability coefficient (cm/s) 1-1 0 1.88E-4 5.04E-08 4.89E-08 1-2 1.85E-4 4.75E-08 2-1 8.3E-3 1.77E-4 4.98E-08 5.08E-08 2-2 1.76E-4 5.17E-08 3-1 8.3E-2 1.09E-4 5.18E-08 5.22E-08 3-2 1.41E-4 5.25E-08 4-1 8.3E-1 1.70E-4 8.42E-08 8.23E-08 4-2 1.70E-4 8.03E-08 5-1 2 1.03E-3 5.13E-07 5.10E-07 5-2 1.03 E-3 5.06E
In coarse grained soils, the thickness of the diffuse double layer is much less than the effective pore diameter and has little effects on the flow of pore water, thus hardly creating MEFES.
Besides, in a thin film flow, while the film thickness is less than ten-molecule-thick layer (about 5 nm), the equivalent viscosity coefficient of polarity water will depend generally on the number of molecule layers and can be increased by 105 times[3].
Pore solutions in the samples are NaCl solutions with different molar concentration, which means the number of moles of solute dissolved in one liter of solution.
Table 1 Geotechnical Properties of the Samples Used in Tests Composition Number e0 ρd (g/cm3) w (%) Averagediameter() CEC cmol/kg Total surface area ( m2/g) Outer surface area ( m2/g) Charge density C/m2 Plasticity index Ip ( %) 1-1 1.64 0.94 67.3 2.5 73.5 456 39.8 0.1554 00% Bentonite 1-2 1.61 0.96 67.0 93.7 2-1 1.62 0.95 65.8 2-2 1.63 0.95 66.3 3-1 1.66 0.94 66.0 3-2 1.65 0.94 65.4 4-1 1.64 0.94 63.8 4-2 1.63 0.95 64.1 5-1 1.63 0.95 63.3 5-2 1.63 0.95 63.4 Table 2 Permeability Coefficient from the Seepage Consolidation Test Results Number NaCl solution concentration ni (mol) Consolidation coefficient Cv(cm2/s) permeability coefficient ka (cm/s) Average permeability coefficient (cm/s) 1-1 0 1.88E-4 5.04E-08 4.89E-08 1-2 1.85E-4 4.75E-08 2-1 8.3E-3 1.77E-4 4.98E-08 5.08E-08 2-2 1.76E-4 5.17E-08 3-1 8.3E-2 1.09E-4 5.18E-08 5.22E-08 3-2 1.41E-4 5.25E-08 4-1 8.3E-1 1.70E-4 8.42E-08 8.23E-08 4-2 1.70E-4 8.03E-08 5-1 2 1.03E-3 5.13E-07 5.10E-07 5-2 1.03 E-3 5.06E
In coarse grained soils, the thickness of the diffuse double layer is much less than the effective pore diameter and has little effects on the flow of pore water, thus hardly creating MEFES.
Online since: December 2010
Authors: Jun Guo, Yun Sheng Wang, Bin Zhang, Xin Ya Song, Xian Li Li
We define sampling period as t. the main factors causing memory consumption is call frequency of web services, basic consumption of memory resources in server systems’ running and the total server memory consumption in last interval, the k+2 input nodes of BP network is, and the server’s total consumption memory in period t-1; the hidden layer 1 and hidden layer nodes number (2k+5); the output node number 1 as the server’s total memory consumption of the period t.
Choosing of hidden nodes number seriously influences the performance of BP network, fewer nodes will lead to poor approximation ability and weak fault tolerance, and more nodes will lead to large scale of BP, long learning time and not minimum error.
In this paper, we initially set the hidden nodes as 2N+1 and eliminate the useless hidden units through continuous learning, until find the best reasonable numbers.
The aging degrees of different stages are different, and we propose an adaptive fine-grained rejuvenation strategy for related services based on the rejuvenation queue and the server ageing state.
First, automatically collecting the total server memory consumption and the number of each service’s calls of multiple cycles in the high reliable stage, initially establishing and fixing the aging model; secondly judging the server status by the server memory consumption.
Choosing of hidden nodes number seriously influences the performance of BP network, fewer nodes will lead to poor approximation ability and weak fault tolerance, and more nodes will lead to large scale of BP, long learning time and not minimum error.
In this paper, we initially set the hidden nodes as 2N+1 and eliminate the useless hidden units through continuous learning, until find the best reasonable numbers.
The aging degrees of different stages are different, and we propose an adaptive fine-grained rejuvenation strategy for related services based on the rejuvenation queue and the server ageing state.
First, automatically collecting the total server memory consumption and the number of each service’s calls of multiple cycles in the high reliable stage, initially establishing and fixing the aging model; secondly judging the server status by the server memory consumption.
Online since: November 2012
Authors: Alexanders Urbahs, Mukharbiy Banov, Vladislav Turko
Physical Basis
In works sanctified to the physical processes of endurance and fatigue stregnth, the following stages of cracks’ origin and propagation are distinguished: the origin of microcracks at the level of size of grain, confluence of microcracks and formation of the magistral main crack’s focus, growth of this main crack to its critical length, and lead to resulting speed-up destruction of inspected unit [3].
To the well-known models that describe the fatigue destruction phenomenological, and that is why are most applied at fatigue strength design, takes the Weibull model of “weak link”: (2) where N – number of load cycles, a, b, m –CDF parameters (respectively position, scale and mode parameters), model of casual accumulation of plural fatigues modest damages (H.Kordonsky, M.Stepnov, V.Kogaev and other): (3) where N - number of load cycles, N0 –cycle sensibility factor, a,b - CDF parameters (respectively position and scale) Evidently, that for satisfactory description of fatigue durability three parameters of CDF are required.
In papers [6, 8] it is shown that at the low levels of loading (large values of the fatigue endurance or the high level of reliability) the CDF is well described by two-parameter expression: (4) where τ = lgN – the logarithm of number of load cycles, а, b – CDF parameters of position and scale Comparing different CDF with fracture character of fatigue destruction it is possible to mark the following, that the model of Weibull “weak link” (2) describes brittle and semibrittle destruction, while the model of an accumulation of many modest fatigue damages (3) is semiductile destruction.
So it results in the model of maximums distribution [6] or to CDF expression (4), where а –position parametrs, b – scale parametrare, Г’(1) = -0,5772…Euiler constant tied with mathimatical expectation Mτ and variance D{τ}: Mτ=a+bГ'1 (5) D{τ}=π2b2/6 (6) Summary A hypothesis on that a full-size construction can be presented as an association of eventual number of some local zones is offered.
Simplest model of the scale effect based on the hypothesis of local volumes Strength of Materials, 1986, Volume 18, Number 4, Pages 455-460
To the well-known models that describe the fatigue destruction phenomenological, and that is why are most applied at fatigue strength design, takes the Weibull model of “weak link”: (2) where N – number of load cycles, a, b, m –CDF parameters (respectively position, scale and mode parameters), model of casual accumulation of plural fatigues modest damages (H.Kordonsky, M.Stepnov, V.Kogaev and other): (3) where N - number of load cycles, N0 –cycle sensibility factor, a,b - CDF parameters (respectively position and scale) Evidently, that for satisfactory description of fatigue durability three parameters of CDF are required.
In papers [6, 8] it is shown that at the low levels of loading (large values of the fatigue endurance or the high level of reliability) the CDF is well described by two-parameter expression: (4) where τ = lgN – the logarithm of number of load cycles, а, b – CDF parameters of position and scale Comparing different CDF with fracture character of fatigue destruction it is possible to mark the following, that the model of Weibull “weak link” (2) describes brittle and semibrittle destruction, while the model of an accumulation of many modest fatigue damages (3) is semiductile destruction.
So it results in the model of maximums distribution [6] or to CDF expression (4), where а –position parametrs, b – scale parametrare, Г’(1) = -0,5772…Euiler constant tied with mathimatical expectation Mτ and variance D{τ}: Mτ=a+bГ'1 (5) D{τ}=π2b2/6 (6) Summary A hypothesis on that a full-size construction can be presented as an association of eventual number of some local zones is offered.
Simplest model of the scale effect based on the hypothesis of local volumes Strength of Materials, 1986, Volume 18, Number 4, Pages 455-460
Online since: May 2014
Authors: Mats Karlberg
i = 1…n, n= number of el
To include strip profile effects the strip width is in the model approximated to consist of a discrete number of fibres.
Eq. 10 has been implemented to the FE model where all temperature trajectories inside the discretised domain continuously are computed whereas the absolute strength level can be formulated as (12) The base strength parameter, σb is typically dependent on chemical composition, ferrite grain size and phase composition etc. which are to be evaluated in the ROT section.
The yield stress was measured at a number of positions along the head and tail parts of the strip where deviations normally are expected.
Number Grade Length [m] Coil radius[m] Width [m] Thickness [mm] Head samples [pcs] Tail samples [pcs] ÄS 110471 HSLA-grade 199 0.72 1.538 6 12 11 The calculations were made for 10800s (3h) on a mesh consisting of 20x20 elements.
To include strip profile effects the strip width is in the model approximated to consist of a discrete number of fibres.
Eq. 10 has been implemented to the FE model where all temperature trajectories inside the discretised domain continuously are computed whereas the absolute strength level can be formulated as (12) The base strength parameter, σb is typically dependent on chemical composition, ferrite grain size and phase composition etc. which are to be evaluated in the ROT section.
The yield stress was measured at a number of positions along the head and tail parts of the strip where deviations normally are expected.
Number Grade Length [m] Coil radius[m] Width [m] Thickness [mm] Head samples [pcs] Tail samples [pcs] ÄS 110471 HSLA-grade 199 0.72 1.538 6 12 11 The calculations were made for 10800s (3h) on a mesh consisting of 20x20 elements.
Online since: March 2014
Authors: Atsushi Sugeta, Jinta Arakawa, Motoki Kakuta, Yoshiichirou Hayashi, Ryota Tanegashima, Hiroyuki Akebono, Masahiko Kato
The run-out number is N=1×107 cycle.
C Si Mn P S Ni Cr N Al Ca O 0.049 0.50 0.83 0.040 0.004 3.62 12.82 0.027 0.010 <0.0005 0.00063 HV σ0.2[MPa] σB[MPa] 280 594 829 Amplitude Vibrational frequency shot distance shot extent shot material shot grain size Time 50mm 20kHz 20mm 76mm×26mm SUJ2 f4.0mm 20sec Fig. 1 Schematic illustration of specimen.
Fatigue tests Figure. 5 shows the results of fatigue tests, which indicates the relationship between stress amplitude at the notch root and number of cycles to failure.
The results of simulation are shown in Fig. 8, which indicates the relationship between crack length, 2a, and number of cycles normalized by simulated number of cycles to failure of Virgin specimen, N/Nf|Virgin.
In Fig. 8, it was assumed that both fatigue cracks in USP specimen and Virgin specimen initiated at the same number of cycles based on experimental results of fatigue crack propagation behavior.
C Si Mn P S Ni Cr N Al Ca O 0.049 0.50 0.83 0.040 0.004 3.62 12.82 0.027 0.010 <0.0005 0.00063 HV σ0.2[MPa] σB[MPa] 280 594 829 Amplitude Vibrational frequency shot distance shot extent shot material shot grain size Time 50mm 20kHz 20mm 76mm×26mm SUJ2 f4.0mm 20sec Fig. 1 Schematic illustration of specimen.
Fatigue tests Figure. 5 shows the results of fatigue tests, which indicates the relationship between stress amplitude at the notch root and number of cycles to failure.
The results of simulation are shown in Fig. 8, which indicates the relationship between crack length, 2a, and number of cycles normalized by simulated number of cycles to failure of Virgin specimen, N/Nf|Virgin.
In Fig. 8, it was assumed that both fatigue cracks in USP specimen and Virgin specimen initiated at the same number of cycles based on experimental results of fatigue crack propagation behavior.