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Online since: May 2012
Authors: Geng Ren, Dun Wu Chen, Shu Li Wang, Man Gen Mu
Specifications of soilcrete columns that are achieved from the jet grouting procedures from the diameter and strength aspect depend on jet grouting parameters such as grout pressure, lifting speed, number and diameter of nozzles and c/w ratio and specifications of local soil.
It is formed by the sediments overflowed from the riverbed and is sorted by waters, its grains are small and even with horizontal bedding and organic matters.
The parameters that should be assigned in single fluid system include grout pressure, number and dimensions of nozzles, W/C rate, rotating speed and lifting speed.
Specifications of soilcrete columns that are achieved from the jet grouting procedures from diameter and strength point depend on jet grouting parameters such as grout pressure, lifting speed, rotating speed, number and diameter of nozzles, cement/water ratio and specifications of local soil.
The air pressure, air flow, water pressure, water flow, number and diameter of nozzles and local soil specification were held constant and then the value of the grout pressure, cement/water ratio, lifting speed and rotating speed, respectively, were changed and the jet grouting parameters are shown in Table 3 and Table 4.
It is formed by the sediments overflowed from the riverbed and is sorted by waters, its grains are small and even with horizontal bedding and organic matters.
The parameters that should be assigned in single fluid system include grout pressure, number and dimensions of nozzles, W/C rate, rotating speed and lifting speed.
Specifications of soilcrete columns that are achieved from the jet grouting procedures from diameter and strength point depend on jet grouting parameters such as grout pressure, lifting speed, rotating speed, number and diameter of nozzles, cement/water ratio and specifications of local soil.
The air pressure, air flow, water pressure, water flow, number and diameter of nozzles and local soil specification were held constant and then the value of the grout pressure, cement/water ratio, lifting speed and rotating speed, respectively, were changed and the jet grouting parameters are shown in Table 3 and Table 4.
Online since: May 2006
Authors: Vladislav V. Kharton, Jorge R. Frade, Fernando M.B. Marques, Ivan P. Marozau
The oxygen transference numbers of SrCe(Y)O3-δ in air vary in
the range 0.37-0.80, decreasing when temperature increases.
The scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and picnometry confirmed a high quality of the ceramic materials, in particular low porosity and absence of secondary phase segregation at the grain boundaries (Fig.1).
Hence, in the temperature range 973-1223 K where the faradaic efficiency and oxygen permeability measurements were performed, the proton transference numbers are low, in agreement with literature [3].
Considering these data in combination with the transference numbers (Fig.4D), one can conclude that the permeation through SrCe(Y)O3-δ ceramics is heavily affected by the hole transport processes, both in the membrane bulk and at the surface.
Although the latter is very low, one can estimate its upper level by comparing the p(O2)-independent contribution to the total conductivity and the results of faradaic efficiency measurements, enabling to determine oxygen ion transport numbers without protonic contribution [5].
The scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and picnometry confirmed a high quality of the ceramic materials, in particular low porosity and absence of secondary phase segregation at the grain boundaries (Fig.1).
Hence, in the temperature range 973-1223 K where the faradaic efficiency and oxygen permeability measurements were performed, the proton transference numbers are low, in agreement with literature [3].
Considering these data in combination with the transference numbers (Fig.4D), one can conclude that the permeation through SrCe(Y)O3-δ ceramics is heavily affected by the hole transport processes, both in the membrane bulk and at the surface.
Although the latter is very low, one can estimate its upper level by comparing the p(O2)-independent contribution to the total conductivity and the results of faradaic efficiency measurements, enabling to determine oxygen ion transport numbers without protonic contribution [5].
Online since: April 2010
Authors: Y.L. Hsu, C.H. Lee, S.M. Chiu, Y.C. Sung, K.Y. Yang, C.W. Chu
From the angle view of the AFM
image, the ZrOx coating shows the smallest and most uniform grain size.
The CrWNx coating had the same surface morphology while some deviations in grain size appeared.
Each cone-like structure comprised many nano-size grains.
The surface OH group density of the film increases with increasing the number of NBOs [19].
Indicating CrOx coatings had more the number of NBOs as well as surface OH group density than ZrOx coatings.
The CrWNx coating had the same surface morphology while some deviations in grain size appeared.
Each cone-like structure comprised many nano-size grains.
The surface OH group density of the film increases with increasing the number of NBOs [19].
Indicating CrOx coatings had more the number of NBOs as well as surface OH group density than ZrOx coatings.
Online since: March 2013
Authors: K.H. Zhang, Shuang Lu, Zhi Qiang Liu, Yong Chao Xu
The simulation results show that the abrasive grains near the addendum, tooth surface and tooth root can be subjected to corresponding shear stress.
Introduction In order to meet the needs of high-speed, heavy duty, low noise and high life expectancy of modern mechanical transmission, a growing number of helical gear transmissions using hardened precision gear, perfection and application of hard-toothed surface finishing are the main development direction of modern gear manufacturing technology.
Helical gear is an involute-column-bevel gear, number of teeth Z=26,helix angle β=15°, normal plane modulus mn=1.25mm, normal plane pressure angle αn=20°, normal plane addendum coefficienth , normal plane headspace coefficient , tooth width B=48mm.
The experimental results display that the surface roughness Ra decreases when the number of machining cycles increases, and Ra value downward trend has slowed with the increase in the number of machining cycles.
Effects of number of working cycles on surface roughness at three positions.
Introduction In order to meet the needs of high-speed, heavy duty, low noise and high life expectancy of modern mechanical transmission, a growing number of helical gear transmissions using hardened precision gear, perfection and application of hard-toothed surface finishing are the main development direction of modern gear manufacturing technology.
Helical gear is an involute-column-bevel gear, number of teeth Z=26,helix angle β=15°, normal plane modulus mn=1.25mm, normal plane pressure angle αn=20°, normal plane addendum coefficienth , normal plane headspace coefficient , tooth width B=48mm.
The experimental results display that the surface roughness Ra decreases when the number of machining cycles increases, and Ra value downward trend has slowed with the increase in the number of machining cycles.
Effects of number of working cycles on surface roughness at three positions.
Online since: May 2020
Authors: Kyrylo Ziborov, Kostiantyn Bas, Olena Svietkina, Jamil Haddad, Valentyna Olishevska
As for Transdniestr, increased lithium content (up to 0.16%) is determined within thin-layered fine-grained feldspar-quartz sandstones.
Lithium ore is light-grey, almost white, fine-grained rock of massive or not clearly maculose structure (sometimes maculose-band structure) consisting mostly of interconnected and interblending quartz-microcline-albite-petalite and quartz-microcline-albite structural-mineral complexes being characteristic metasomatic formations of metamorphosed original pegmatites.
The height of a grinding chamber and a number of passes of the material through it determine L value.
Obviously, crystallites are formed in the mineral due to the destruction process within the high-angle boundaries of the grains.
Mechanochemical ore activation for complete or partial release of mineral grains. 2.
Lithium ore is light-grey, almost white, fine-grained rock of massive or not clearly maculose structure (sometimes maculose-band structure) consisting mostly of interconnected and interblending quartz-microcline-albite-petalite and quartz-microcline-albite structural-mineral complexes being characteristic metasomatic formations of metamorphosed original pegmatites.
The height of a grinding chamber and a number of passes of the material through it determine L value.
Obviously, crystallites are formed in the mineral due to the destruction process within the high-angle boundaries of the grains.
Mechanochemical ore activation for complete or partial release of mineral grains. 2.
Online since: July 2011
Authors: Wen Hua Li, Shi Sheng Zhou, Xu Dong Chen
Abstract: High-strength flowing concrete is made of large volume of gelled materials and high rate of sand, but low content of coarse aggregate and small grain diameter, which makes it easy to have a greater contraction, resulting in reduced strength and durability of concrete[4] .So the right amount of expansion admixture is needed to ensure that there is no shrinkage or micro-expansion of the concrete.
Table1-1 The cement clinker composition of Huaxin ordinary silicon 42.5 chemical composition (%) SiO2 Al2O3 Fe2O3 CaO MgO SO3 Loss 22.56 5.10 3.52 60.05 3.41 2.26 3.10 Table 1-2 Physical and mechanical performance index of Huaxin 42.5 ordinary silicon cement name of samples result Normal consistency water consumption% setting time rupture strength (MPa) compressive strength (MPa) Proportion (g/cm3) Initial set Final set Three days Twenty-eight days Three days Twenty-eight days national standard / ≮45min ≯10h ≥3.5 ≥6.5 ≥16.0 ≥42.5 / Results of observation 24.5 140min 4h10min 4.0 7.0 18.9 44.9 3.18 Table 1-3 List of cement species Number Name of manufacture factory Brand Varieties 1 Hubei Xinhua Cement Plant Fort Brand 42.5P.O Cement 2 Guangzhou Cement Plant Golden sheep Brand 42.5P.Ⅱ Cement 3 Cement Plant of Yao County, Xi’an Province Qin Ling Brand 42.5P.O Cement 4 Tianjin Cement Plant Camel Brand 42.5P.O Cement 5 Tianjin Building Materials Group Zheng Tong Brand
number The amount of gelled materials (kg/m3) Water (kg/m3) Share of additive in the total gelled materials (%) Sand (kg/m3) Limesone (kg/m3) cement Fly ash Silica fume Expansion admixture 1 435 83 / 32 163 CAN 1.50 688 1032 2 427 83 / 40 165 CAN 1.50 688 1032 3 455 35 / 40 165 CAN 1.50 692 1038 4 430 71 36 58 170 CAN 1.50 638 1041 5 428 60 / 60 170 CAN 1.50 688 1032 6 461 105 84 70 165 CAN 1.55 566 1003 7 496 70 84 70 165 CAN 1.55 566 1003 3.1 Concrete workability and mechanical properties The properties of the concrete mixture and the mechanical properties of concrete in different ages are shown in Table 3-1 [5].
Table 3-1 Performance test of the flowable high strength concrete number Initial concrete properties Concrete properties after 90min Compressive strength (MPa) Slump flow (cm) Time for flowing to 50cm(s) Time for funnel to flow down (s) Fill density (%) Slump flow (cm) Time for flowing to 50cm (s) Time for funnel to flow down (s) Fill density (%) f3 f7 f28 1 64×65 13.1 14.5 85.7 59×53 15.0 15.4 79.2 39.7 50.5 59.7 2 67×68 9.8 10.1 95.4 65×66 11.1 11.5 92.7 41.7 55.9 62.1 3 59×61 10.5 12.4 80.1 54×56 12.5 13.5 90.1 45.9 61.5 73.5 4 66×63 9.0 11.4 90.5 66×65 109 13.2 88.5 57.8 62.8 65.7 5 68×69 8.9 10.4 95.6 67×67 11.3 12.7 93.9 61.0 68.7 74.7 6 66×67 8.5 9.2 93.7 66×65 10.9 11.5 90.8 54.6 62.8 90.3 7 68×62 8.7 10.1 95.7 64×65 11.0 13.3 92.4 56.0 65.3 92.5 Note: ordinary portland cement 42.5 is adopted in group one to five, and ordinary portland cement 52.5 is adopted in group six to seven.
Table 3-2 The limited swelling rate of the high-strength fluid concrete Number 7d 14d 28d 60d 180d 1 0.017 0.019 -0.008 -0.021 -0.022 2 0.015 0.020 -0.006 -0.016 -0.017 3 0.016 0.018 -0.005 -0.017 -0.020 Note: The mixture ratio can be seen in Table 3-1 as 1,2,3.
Table1-1 The cement clinker composition of Huaxin ordinary silicon 42.5 chemical composition (%) SiO2 Al2O3 Fe2O3 CaO MgO SO3 Loss 22.56 5.10 3.52 60.05 3.41 2.26 3.10 Table 1-2 Physical and mechanical performance index of Huaxin 42.5 ordinary silicon cement name of samples result Normal consistency water consumption% setting time rupture strength (MPa) compressive strength (MPa) Proportion (g/cm3) Initial set Final set Three days Twenty-eight days Three days Twenty-eight days national standard / ≮45min ≯10h ≥3.5 ≥6.5 ≥16.0 ≥42.5 / Results of observation 24.5 140min 4h10min 4.0 7.0 18.9 44.9 3.18 Table 1-3 List of cement species Number Name of manufacture factory Brand Varieties 1 Hubei Xinhua Cement Plant Fort Brand 42.5P.O Cement 2 Guangzhou Cement Plant Golden sheep Brand 42.5P.Ⅱ Cement 3 Cement Plant of Yao County, Xi’an Province Qin Ling Brand 42.5P.O Cement 4 Tianjin Cement Plant Camel Brand 42.5P.O Cement 5 Tianjin Building Materials Group Zheng Tong Brand
number The amount of gelled materials (kg/m3) Water (kg/m3) Share of additive in the total gelled materials (%) Sand (kg/m3) Limesone (kg/m3) cement Fly ash Silica fume Expansion admixture 1 435 83 / 32 163 CAN 1.50 688 1032 2 427 83 / 40 165 CAN 1.50 688 1032 3 455 35 / 40 165 CAN 1.50 692 1038 4 430 71 36 58 170 CAN 1.50 638 1041 5 428 60 / 60 170 CAN 1.50 688 1032 6 461 105 84 70 165 CAN 1.55 566 1003 7 496 70 84 70 165 CAN 1.55 566 1003 3.1 Concrete workability and mechanical properties The properties of the concrete mixture and the mechanical properties of concrete in different ages are shown in Table 3-1 [5].
Table 3-1 Performance test of the flowable high strength concrete number Initial concrete properties Concrete properties after 90min Compressive strength (MPa) Slump flow (cm) Time for flowing to 50cm(s) Time for funnel to flow down (s) Fill density (%) Slump flow (cm) Time for flowing to 50cm (s) Time for funnel to flow down (s) Fill density (%) f3 f7 f28 1 64×65 13.1 14.5 85.7 59×53 15.0 15.4 79.2 39.7 50.5 59.7 2 67×68 9.8 10.1 95.4 65×66 11.1 11.5 92.7 41.7 55.9 62.1 3 59×61 10.5 12.4 80.1 54×56 12.5 13.5 90.1 45.9 61.5 73.5 4 66×63 9.0 11.4 90.5 66×65 109 13.2 88.5 57.8 62.8 65.7 5 68×69 8.9 10.4 95.6 67×67 11.3 12.7 93.9 61.0 68.7 74.7 6 66×67 8.5 9.2 93.7 66×65 10.9 11.5 90.8 54.6 62.8 90.3 7 68×62 8.7 10.1 95.7 64×65 11.0 13.3 92.4 56.0 65.3 92.5 Note: ordinary portland cement 42.5 is adopted in group one to five, and ordinary portland cement 52.5 is adopted in group six to seven.
Table 3-2 The limited swelling rate of the high-strength fluid concrete Number 7d 14d 28d 60d 180d 1 0.017 0.019 -0.008 -0.021 -0.022 2 0.015 0.020 -0.006 -0.016 -0.017 3 0.016 0.018 -0.005 -0.017 -0.020 Note: The mixture ratio can be seen in Table 3-1 as 1,2,3.
Online since: September 2013
Authors: Tao Zhang, Zhen Xiu Wu, Zhao Hui Sun
The high-density ammonium polyvanadate was prepared by means of fine-grained ammonium polyvanadate (APV) produced in vanadium plant.
So far, APV is mostly used to smelting ferrovanadium alloys, which requires the density of APV above 0.6g/cm3 and the denser the better [3], but a number of low-density APV is unfavorable to smelt V-Fe alloys.
[3] Yi Peng, Qianwen Li, Qingrong Xia, Xiaojiang Wang, Mingfu Peng, Shengyou Zhu, Ronghua Liao, Publication Number CN1594106A, in Chinese
So far, APV is mostly used to smelting ferrovanadium alloys, which requires the density of APV above 0.6g/cm3 and the denser the better [3], but a number of low-density APV is unfavorable to smelt V-Fe alloys.
[3] Yi Peng, Qianwen Li, Qingrong Xia, Xiaojiang Wang, Mingfu Peng, Shengyou Zhu, Ronghua Liao, Publication Number CN1594106A, in Chinese
Online since: March 2007
Authors: Tim P. Mitchell, Ruth Sanderson, Bruce G.I. Dance
FEA modelling of the process has
been used to reduce the total number of practical tests, and hence, to conserve the limited material
supply.
At present the full capabilities of this approach are unknown and the number of variables is extensive making experimental investigation complex and time consuming.
To reduce the number of practical trials, FEA welding simulations were produced using sequentially coupled thermal and elastic-plastic stress analyses.
Numerous alloying additions are needed to achieve this high strength and high temperature resistance and each one contributes to the overall performance of the alloy, be it in the form of the matrix, gamma prime, grain boundaries, carbide formation, or oxide scale.
This increased the complexity of the pattern and increased the number of programmed points to over 4500.
At present the full capabilities of this approach are unknown and the number of variables is extensive making experimental investigation complex and time consuming.
To reduce the number of practical trials, FEA welding simulations were produced using sequentially coupled thermal and elastic-plastic stress analyses.
Numerous alloying additions are needed to achieve this high strength and high temperature resistance and each one contributes to the overall performance of the alloy, be it in the form of the matrix, gamma prime, grain boundaries, carbide formation, or oxide scale.
This increased the complexity of the pattern and increased the number of programmed points to over 4500.
Online since: November 2014
Authors: Pei Huang
Statistics show that, with the gradual improvement of power grid construction, power systems has obtains significantly higher levels of security and stability, which undermines the stability of the power system significantly and decreases the number of accidents.
However, the way of increasing the number of reactive-load compensation equipment could cause the big investment, which is not economic.
The crossover is creating new offspring from two chromosomes, and the crossover manipulation is single point operator in this paper, which is generating a random number to determine the position of each integer encoding exchanged individuals.
Fig.1 IEEE30 nodes system wiring diagram The grain is used to calculate the effect of parity on genetic algorithm, if standard transformer IEEE30 node data base ratio and the number of shunt capacitor bank switching operation of the system are beyond limit, the genetic algorithm optimization is taken.
The genetic algorithm to calculate the parameters is set as follows: population size is 40, the maximum number of iterations is 30, the probability of 0.8 hybridization, mutation probability is 0.001, the range of the node voltage constraints are as: 0.95 ~ 1.0 (5p.u.)0.
However, the way of increasing the number of reactive-load compensation equipment could cause the big investment, which is not economic.
The crossover is creating new offspring from two chromosomes, and the crossover manipulation is single point operator in this paper, which is generating a random number to determine the position of each integer encoding exchanged individuals.
Fig.1 IEEE30 nodes system wiring diagram The grain is used to calculate the effect of parity on genetic algorithm, if standard transformer IEEE30 node data base ratio and the number of shunt capacitor bank switching operation of the system are beyond limit, the genetic algorithm optimization is taken.
The genetic algorithm to calculate the parameters is set as follows: population size is 40, the maximum number of iterations is 30, the probability of 0.8 hybridization, mutation probability is 0.001, the range of the node voltage constraints are as: 0.95 ~ 1.0 (5p.u.)0.
Online since: April 2014
Authors: Xiong Wei, Zhi Ying Wang, Min Hua Jiang
In terms of the active demand on data parallel processing by rapid rise magnanimous data storage, this paper has adopted GPU accelerator on active memory system node to improve parallel processing capability of mass data, monitored and analyzed resources of data transmission in the system, processor use ratio, I/O operation and system speed-up ratio etc. during the runtime of application programs and adopted methods of rational task partitioning strategy and thread parallel grain size etc. to optimize system performance.
Task arriving process is to describe the task source and arriving laws, finite set or infinite set of task source number and task totality.
Queuing rule refers to the processing rule when arriving task number is larger than processor number, generally divided into loss type, waiting type and mixing type.
Processing pattern of processor mainly includes the processor number, parallel, serial or mixing mode among processors and random or parallel task processing time etc. 1. 2. 3. 3.1. 3.2. 2.
Classification of task queue model A queue model has task arriving process, processing time distribution, processor number, system capacity, client source number and processing rule, which can be represented as: Formula1 In which X represents for the interval time distribution of new tasks’ successive arriving, Y for the task processing time distribution in processor, Z for processor number, A for system capacity limitation, B for task source number and C for processing rule. 3.
Task arriving process is to describe the task source and arriving laws, finite set or infinite set of task source number and task totality.
Queuing rule refers to the processing rule when arriving task number is larger than processor number, generally divided into loss type, waiting type and mixing type.
Processing pattern of processor mainly includes the processor number, parallel, serial or mixing mode among processors and random or parallel task processing time etc. 1. 2. 3. 3.1. 3.2. 2.
Classification of task queue model A queue model has task arriving process, processing time distribution, processor number, system capacity, client source number and processing rule, which can be represented as: Formula1 In which X represents for the interval time distribution of new tasks’ successive arriving, Y for the task processing time distribution in processor, Z for processor number, A for system capacity limitation, B for task source number and C for processing rule. 3.