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Online since: September 2014
Authors: Sheng Guo Cheng, Xiao Hu Chen, Shan Lin
Introduction With the development and understanding of engineering practice field deepening awareness of that structural planes such as geological fault fracture zone in the rock,soft interlayer,joints and fissures tend to become jointed dam stability and security control factor.A large number of engineering practice shows that Can directly use after dam foundation surface for the excavation to good rock mass is rarely more complex geological defects,such as faults and fissures,at this time if you continue to deepen the depth of excavation of the dam foundation,is contrary to the economic rationality of the project.Practice shows that the geological defects after some treatment measures such as consolidation grouting and curtain grouting to meet the requirements of the construction group[1][4].
Clearing is the foundation in soft soil,part of the table with rock or shallow weak intercalations remove broken dam foundation rock weathering,so that a more complete fresh dam located denser solid rock or soil above[3].Yueliangwan Reservoir according to the basic geological conditions after excavation,foundation and existing geological features of two dam toe slab foundation clear foundation Quaternary residual and completely weathered rock and some strong weathered rock,river clear Quaternary deposit and weakly upper weathered broken rock.clear base depth:the depth of the left abutment clear base 5~10m,clear river segment plinth base depth of 13~18m,right abutment clear base depth 3~7m.Silt layer of dam cross 0+161.419~0+071.419 section must be clear to its gravel layer.After the excavation of compacted layered roller compacted backfill.Backfill with maximum diameter≤30cm,particle size of less than 10cm should be greater than 15%,the content of particles with grain size less than 5mm
(1) Consolidation grouting layout and engineering Consolidation grouting holes arranged in the dam toe and spillway and dam axis intersection range,when toe slab width is 7m,6m,consolidation grouting with 3 rows,row spacing of 3.0m and 1.0m of two,pitch 2m,hole depth 8m;When toe board width is 5m,with 2 rows of consolidation grouting,row spacing is 3.0m,pitch 2m,hole depth 8m,spillway and dam axis intersects with 2 rows of consolidation grouting,row spacing is 2.0m,pitch 2m,hole depth 8m.Consolidation Grouting axis length of 429m,the total number of holes 574 holes,consolidation grouting total hole depth 4592m,filling segment length 4592m.The toe slab foundation by deep hole grouting,hole depth 8m
(2) Curtain grouting layout and engineering The range of curtain grouting:The left abutment of curtain grouting for dam is left along the existing traffic platform to extend 220m,curtain grouting on,the right abutment of the dam along the right endpoint for the right end of the existing traffic platform to extend the 150m,total length curtain 770m.Grout curtain along the base plinth furnished 2,row pitch is 2m,row spacing 1.2m.The total number of holes 573,total pore 19251.4m,including non-irrigation segment 2511.8m,irrigation segment 16739.6m.To ensure the dam foundation grouting include locally strong permeable layer,riverbed toe 0+060~0+320 curtain grouting depth required 5Lu bottom interface and design of deep hole control[5].
Online since: December 2013
Authors: Yeon Wook Kim, Jae Hoon Kim, Bo Hwi Seo, Hoon Seok Choi, Sung Han Park, Hwan Kyu Lee
(a) Upper Specimen (b) Lower Specimen (c) Reciprocating wear test Fig.1Schematic Diagram of test specimens and reciprocating wear test Table 1 The mechanical properties of graphite, HK-6 Density [g/cm3] Flexural Strength [MPa] Grain Size [μm] Shore Hardness [Hs] 1.86 85 3 68 Table 2 The mechanical properties of W-25Re Density [g/cm3] Tensile Strength [MPa] Poission Ratio Shear Modulus [GPa] Shore Hardness [Hs] 19.7 1370 0.29 159 43 Experimental work Experimental Materials.Graphite HK-6, the test material, is made by the Tokai Carbon Co.
There have been many attempts to predict sliding wear rate and the wear formula of Archard is the most acknowledged in the field[8]: V=kSFNH (1) Where V is the volumetric wear, k is the dimensionless wear coefficient, s is the sliding distance, FN is the applied normal load, and H is the hardness number of the softer material.
Ltd, Korea) Experimental Design.The response surface methodology (RSM) consists of agroup of techniques used in the empirical study of relationshipsbetween one or more measured responses and a number of inputfactors.
(3) Where X1, X2, . . , Xk are the input factors which affect the response Y andk is the number of input factors asβ0, βi(i=1, 2, . . , k) and βij(i=1,2, . . , k, j=1,2, . . , k)are the unknown parameters (regression coefficients or parameters) and ε is random error.
Online since: April 2014
Authors: Joanna Przondziono, Witold Walke, Janusz Szala, Eugeniusz Hadasik, Jakub Wieczorek
It results both from the number of technological problems during plastic working (which is connected with their low formability at ambient temperature) and high production costs.
Thanks to favorable thermo-mechanical conditions, the hydrostatic extrusion process can be performed at lower temperatures and it is possible to obtain greater magnesium alloy grain size reduction.
When the time of exposure increases, the number of pits increases substantially.
During the process, anodic dissolution of the alloy surface takes place and a large number of pits can be observed.
Online since: March 2014
Authors: Dietmar Eifler, Marek Smaga, Robert Skorupski
The microstructure is homogeneous with a small grain size of 17 µm determined including twins.
The same number of cycles did not cause any change of the surface topography of the MSLp specimens (comp.
In contrast, the specimens with MSLp achieved the same number of cycles without failure.
Already after 10 cycles (about 1 % fatigue life) a higher number of slip bands was observed at ASLp specimens.
Online since: August 2014
Authors: Manuel François, Fabien Lefebvre, C. Fischer, L. Desmas, A. Ouakka, M.J. Moya, Y. Bordiec, H. Hamdi, E. Wasniewski, J. Cacot, P. Le-Bec, E. Baumhauer, D. Bouscaud, T. Bergey, D. Blaize, D. Gloaguen, A. Cosson, S. Jegou, Y. Cheynet, S. Leray, M. Meheux, J.C. Monvoisin, P. Allain, J.C. Vidal, J.M. Sprauel, P. Goudeau, C. Charles, L. Daflon
[6] EN_15305 – 2009 Non-destructive testing – Test method for residual stress analysis by X-ray diffraction [7] ISO 5725-1993 1993 Accuracy (Trueness and Precision) of Measurement Methods and Results, Parts 1–6 (Geneva: International Standardization Organization) APPENDIX : Certificate APPENDIX GFAC Certificat Reference sample for residual stress analyses by X-ray diffraction 10mm 25mm Direction d'analyse · Sample: GFAC2013I01 · Sample fabrication: Electricité de France (EDF) · Material: NiCr30Fe (Inconel 690) · Metallurgical state: recristallised at 1040 °C + 5h 700 °C · Grain size: 40 à 60 µm · Mechanical state: shot peened (Metal Improvement Compagny MIC) / Parameters: BC210/F18-F26N/125%/spécif.
stress for all batches: 20 samples (MPa) rt: Repeatability of the shear stress of the material (MPa) Rt: Reproducibility of the shear stress of the material (MPa) · Sample Characteristics: σe rσe Rσe te rte Rte -741 39 67 -11 16 28 σe: normal stress for this given sample (MPa) rσ: Repeatability of the normal stress of this given sample (MPa) Rσ: Reproducibility of the normal stress of this given sample (MPa) te: Shear stress for this given sample (MPa) rt: Repeatability of the shear stress of this given sample (MPa) Rt: Reproducibility of the shear stress of this given sample (MPa) · Nota: the Repeatability and Reproducibility are respectively equal to 2,8 times the standard deviation of repeatability and 2,8 times the standard deviation of reproducibility in the case of simple comparison · Experimental conditions Crystallographic plane: {311} Radiation: Mn Ka Spot size (on the sample surface and at ψ = 0°): 2,7mm² Location of measurement: Center of the spotted face Minimum number
Choice of the number n of measurements to be carried out on this sample in the repeatability conditions for the qualification or verification of the system.
The number n (n ≥ 1 for the verification or n ≥ 4 for qualification) depends on the quality system of the laboratory. 3.
Online since: January 2017
Authors: Zhi Tong, Rui Hua Mu, Jing Yang, Bao Song Li
The total number of Pd(NO3)2·2H2O and AgNO3 moles was kept constant during the synthesis, namely, [Pd(NO3)2·2H2O+AgNO3]/TEOS=0.1.
In Fig.5(a), for the sample of nPd/Ag=0, the diffraction peaks at 2θ = 38.18, 44.33, 64.36, 77.39 and 81.50° are assigned to the (111), (200), (220), (311) and (222) planes of a face centered cubic (fcc) lattice of metallic Ag0, respectively, with the PDF card number of 65-2871.
When the nPd/Ag is increased to 9:1, we can observed the diffraction peaks of metallic Pd0 with the PDF card number of 46-1043, which are located at 2θ=40.1, 46.6, 68.1, 79.62 and 82.1°, respectively.
It means the formed grain size of Pd/Ag/SiO2 materials after calcining at 350°C increases according to the Scherer’s equation [31].
Online since: September 2013
Authors: Guo Fang Kuang, Chun Lin Kuang
IPv6 security mechanisms and their performance trends: on the one hand, the network dramatic development caused by the IPv4 limited resources design highlights directly caused by the network address shortage crisis, and this crisis is increasingly showing exacerbate existing network security system; the other hand, for the security and privacy considerations, a growing number of commercial organizations and government departments are no longer willing to send their sensitive information and the exchange of information in plaintext in an insecure network, leading to encryption and authentication needs of rapid growth.
Due to the great number of nodes in the same subnet support (up to the order of magnitude of a billion billion), hackers found through the scanned host the difficulty greatly increased.
Because of the very large number of addresses, and even if it is a grain of sand, can have its own IP address.
Online since: June 2015
Authors: R. Szatanik, Halyna Klym, O. Shpotyuk, A. Ingram, E. Petracovschi, L. Calvez, C. Lin
HOWEVER, THE NUMBER OF PROBES AVAILABLE TO STUDY ATOMIC-DEFICIENT DISTRIBUTION IS RATHER LIMITED, ESPECIALLY AT A SUB-NANOMETER DOMAIN.
ONE OF THE BEST TECHNIQUES APPLICABLE TO DIFFERENT SOLIDS WHATEVER THEIR STRUCTURAL ORGANIZATION (CRYSTALS OR GLASSES, FINE-GRAINED OR COARSE POWDERS, CERAMICS, BULK ALLOYS OR THICK-FILM STRUCTURES) [8-10] IS POSITRON ANNIHILATION (PA).
Each spectrum was measured with a channel width of 6.15 ps (the total number of channels was 8000) and contained at least ~106 coincidences in a total, which can be considered as conditions for normal PAL measurement statistics.
In addition, the (t2 - tb) difference was accepted as a size measure for extended free-volume defects where positrons are trapped (in terms of equivalent number of monovacancies), as well as the t2/tb ratio was taken in a direct correlation to the nature of these defects [17-20].
Online since: August 2016
Authors: Lakhdar Taleb, Crescent Kpodekon
Stress amplitude versus the number of cycles for SC tests Fig. 4.
Plastic strain amplitude versus the number of cycles for SC and LC tests From these results, it appears that contrary to LC conditions, the pre-hardening reduces significantly the fatigue life under SC even in presence of compressive mean stress (Table 2).
Relaxation of the mean stresses according to the number of cycles in SC tests As it is shown in Fig. 3, the stress amplitudes of pre-hardened specimens are significantly more important than the amplitudes of virgin ones.
As it has been earlier pointed out in other work about 316L SS [20], the evolution of all stress components is directly related to the modification of dislocation densities and distributions in the grains.
Online since: September 2017
Authors: Peter Olegovich Rusinov, Etibar Yusif O. Balaev, Maria Evgenievna Bezmogorychnaya, Anna Pavlovna Yurkova, Zhesfina Blednova
HVOF process was carried out on the modernized GLC (patent number 2,535,432), equipped with a vacuum chamber, a device for moving the flame burner, technology module for ion cleaning of components surfaces, the device supplying the liquid nitrogen, gas supply system, a device for surface plastic deformation of the coating.
The investigations have shown that the SM of TiNi allows you to manage the technological heredity [8] and achieve stable quantitative result of a number of characteristics (surface roughness, grain size, fractal dimension, adaptability), and a complex of properties (microhardness, cyclic durability, endurance limit, wear rate).
The technological process of surface layers formation with shape memory materials in a single technological cycle (Pat number 2,502,829) provides for SPD operation training.
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