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Online since: April 2016
Authors: Leila Mahdavian, Nasim Sarami
The compressive strength (product Toni tecknik Germany with device number PR41004).
The flexural strength (number of products, Toni tecknik Germany (RB421002).
With the addition of titanium dioxide nanoparticles, properties of samples increase, but the effect of TiO2 nanoparticles in SSCF are more because depends to expansion of the surface and the crystal structure of titanium dioxide nanoparticles and grain size of the lesions.
[19]ISO 8486-1: 1996, Bonded abrasives - Determination and designation of grain size distribution - Part 1: Macrogrits F4 to F220
Online since: August 2006
Authors: Sayuri Matsuoka, Satoru Takahashi, Masayuki Yoshiba, Yoshio Harada, Wataru Kakuta
On the other hand, C2S-CZ system (MSV) is characterized by the TC bearing a great number of the dispersive micro-cracks which should be Table 1 Coating processing and reheat treatment for Mar-M247 (MB) and various TBC systems.
Under the static creep loading, it was confirmed that typical creep rupture is caused of TBC systems according to typical creep failure manner; by the nucleation and coalescence of the grain boundary cracks in the alloy substrate interior by the manner essentially similar to the MB specimen without TBC.
the TC surface of such an interfacial crack by the coalescence with a number of dispersive TC cracks.
Conclusions (1) Under static creep loading, all kinds of TBC systems exhibited the typical creep rupture behavior regardless of the environmental condition, with the manner of the nucleation and coalescence of mainly the grain boundary cracks in the alloy substrate interior.
Online since: November 2014
Authors: Xin Yi Zhao, Shi Bao Li, Xu Gong
It is known that backscattered electrons (BSE) image of SEM is able to distinguish areas with different atomic, since the brightness of the BSE image tends to increase with a higher atomic number [9,10].
Therefore the brighter areas in the BSE image represent the existence of silver atoms beacause the atomic number of silver is much higher than other elements existed in dentin and resin.
In contrast to BSE, the power of electron beam for secondary electron image is lower, resulting in a less bright in areas containing silver atoms or grains.
Taking example for Clearfil SE Bond, Suppa et al [12] and Reis et al [13] observed silver grains dis- continuously distributed within hybrid layer, whereas Duarte et al [14] presented clusters of silver aggregated in zone within hybrid layer, the difference was significant.
Online since: October 2014
Authors: Hai Jun Xing, Zi Fu Zhang, Bin Rong Zhu, Zhen Fu Li, Xin Tuo Hou
Testing Results of Silica Fume Compositions SiO2 Fe2O3 AL2O3 CaO MgO K2O Na2O SiC SO3 Ignition loss Content (%) 92.22 1.81 0.97 0.36 1.31 0.84 0.16 0.92 0.27 1.45 Aggregate: Take medium and coarse grained river sand as fine aggregate.
Therefore, take medium and coarse grained river sand as fine aggregate, and particle size range of coarse aggregate shall be controlled within 10-25mm
For meanings of serial number, take 48-F1 as an example: 48 - Total amount of cementation materials is 480kg/m3, 52 - Total amount of cementation materials is 520kg/m3, F - Mineral admixture is fly ash, S - Mineral admixture is silica fume, FS - Mineral admixtures are fly ash and silica fume.
Comparing the strengths after 12h steam curing and 3d standard curing, the former is higher than the latter mostly, and only a small number of 3d strengths are a little higher than 12h strengths, indicating that steam curing can obviously improve early strength of concrete.
Online since: October 2006
Authors: Vito Raineri, Salvatore Lombardo, Patrick Fiorenza, Roberta G. Toro, Graziella Malandrino, Ignazio L. Fragalà, Raffaella Lo Nigro
In the cross-section HR-TEM image three layers are clearly visible: a SiO2 layer in direct contact with the Si substrate, a bottom 8 nm Pr-oxide based layer having a different contrast than the SiO2 layer and no long range order, and well defined Pr2O3 crystalline grains.
The shift value can be used to quantify the number of fixed or trapped charges (Nf, Not [cm -2]) in the dielectric films using the equation: eA VC N ∆ = where C is the accumulation capacitance, e is the electron charge, A is the area of the gate and ∆V is the flat band shift.
The number of trapped (negative) charges (Not [cm -2]) has been evaluated from the hysteresis observed in the C-V curve and it is quantified as Not = 1.6×1011 cm -2.
These defects can be mainly referred as bulk defects and appear not to be related to morphological defects such as the presence of grain boundaries.
Online since: November 2023
Authors: Alena Sicakova, Stefan Kusnir
A substantial number of researchers have reviewed the improvement ways of properties of recycled concrete aggregates.
The properties of concrete with treated RBA will however also be influenced by other parameters, especially by the character of grain sur-face after treatment and by properties of interfacial transition zone.
Sicakova, Methods of strengthening the grains of recycled aggregates, In: IOP Conf.
Akrami, Performance of concrete produced with crushed bricks as the coarse and fine aggregate, In IAEG 2006, The Geological Society of London: London, UK, 2006; p. 10, paper number 616.
Online since: May 2011
Authors: Nai Qi Jiao, Di Tao Niu, Yan Wang
In recent years, many researchers at home and abroad make a number of experiments and theoretical analysis on structural performance of steel fiber reinforced shotconcrete[1-6].Among them, Professor Du Guoping researches the enhancement mechanism of steel fiber reinforced shotconcrete from the viewpoint of its mechanical property [7] ; Professor Liu Xin carried out experimental study of basic mechanical properties of steel fiber reinforced shotconcrete from the viewpoint of this actual work [8]; But the research about the influence on concrete micro pore structure under different construction technology is still small.
In this paper, we do experiments on pore structure of steel fiber reinforced shotconcrete , use mercury intrusion method to test pore structure ,analyse and compare effect on concrete matrix pore structure with sprayed build and model build , and then from the microscopic point of view, analyze the effect on the mechanical properties and durability of steel fiber reinforced concrete under thus different construction technology. 2 raw materials and test methods. 2.1 raw materials Steel fibers used as shear waving steel fibers, produced by Chongqing Yizhu Trading Company , slenderness ratio is 60, tensile strength is greater than 500 MPa; Huaxin cement 42.5R ordinary portland cement is used to meet the requirements; coarse aggregate used machine processed gravel at the scene of the tunnel,for the Crossing site mechanism gravel, grain diameter is 6.0 ~ 10.8 mm continuous grading ; fine aggregate used compound with machine processed gravel and Yichang middle-thick river sand at the scene
Admixtures used highly active alkali-free liquid accelerating agent and highly active water reducing agent produced by Germany BASF corporation; ganister sand uesd silica fume produced in Chongqing, the average grain diameter is 0.1 microns; mixing water used on-site drinking water. 2.2 test method The commonly used gaging pore methods are of optical microscopy, electron microscopy, mercury intrusion method, adsorption methods, X-ray small angle diffraction method and so on.
Based on the pore distribution curve of mercury intrusion test, is the quantitative characterized form between pore diameter of steel fiber reinforced concrete and pore size, number.The curve is a cumulative distribution curve, can visually and quantitatively show the composition and distribution of pores, as Figure 2.Table 4 in which the critical pore size is defined as the amount of mercury pressed into the corresponding significant increases of steel fiber reinforced concrete maximum pore size; most probable pore size refers to the corresponding peak value of pore size.
Online since: April 2014
Authors: Lin Yang, Ya Ling Han, Li Qiang Deng, Yang Han
Test condition of wear resistance are as follows: the abrasive grains are 40 purpose, the most-positive pressure is 23kg, the standard speed is 240r/min, testing time is 5 min, the size of the sample is 10mm×20mm×60mm .
Table 2 Heat treatment processes Serial number Heat treatment processes Process one Process two Process three Process four Diffusion annealing+880℃×2h×oil quenching+180℃×2h×air cooling Diffusion annealing+880℃×2h×oil quenching+220℃×2h×air cooling Diffusion annealing+880℃×2h×oil quenching+260℃×2h×air cooling Diffusion annealing+880℃×2h×oil quenching+500℃×2h×air cooling Results and Analysis Microstructure and Hardness at Cast and Diffusion Annealing States.
Without any indication of brittle flake or the form of loose sediments of multiple carbide and WC ceramic phase,there is a large number of parallel cutting grooves, and the grooves orientation are identical basically, no present the transverse or oblique furrows, showing that the surface hardness is large under the process, wear sands cannot transverse or oblique cutting, wear-resisting performance is better.
The wear resistance is higher with tempering sorbite + WC grains dues to the evenly distributed carbide particles between the short ferrite lath bundle skeleton matrix in the tempered sorbite, The fatigue crack is not only hampered by ferrite phase interface when extending from surface layer to the surface during wear process, but also occurs plastic deformation, which makes the crack tip stress relaxation and inhibits the extension [15].
Online since: May 2014
Authors: Anthony D. Rollett, Mark Iadicola, Adam Creuziger, Tim Foecke, Minh Son Pham
Constitutive equations At the grain level, the plastic strain rate is given by the sum of the shear strain rates from all the active slip systems , (3) where N is the number of slip systems, is the Schmid tensor of the slip system .
Stable multi-junctions can undergo a maximum number of three serial higher-order non-coplanar interaction types during deformation.
Self-consistent polycrystal models: a directional compliance criterion to describe grain interactions.
Online since: October 2016
Authors: Masaaki Otsu
Since a number of reports about friction stir incremental forming are not so many and most of them are presented by the authors’ group, results about friction stir incremental forming by the authors’ group are introduced in this paper.
Area of occurring dynamic recrystallization and grain refinement by friction stir incremental forming is considerable to be limited to certain depth from the surface.
AZ80 sheet was thicker and the effect of dynamic recrystallization and grain refinement on the improvement of formability was smaller than those of AZ31 ones.
Acknowledgement Researches introduced in this paper are financially supported by JSPS KAKENHI Grant Number 22360309 and 25289261, and Cross-ministerial Strategic Innovation Promotion Program from Japanese government.
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