Search results

Shrinkage ratio was denoted by the ratio of length variation value to original length, positive number indicating shrinkage and negative indicating swell. 2.2.2 Volume measurement After mixed, the fresh concrete was poured into a glass bottle with a 5 L or 2.5 L capacity, and the concrete mass was about the 4/5 of the bottle capacity, then, Liquid paraffin was poured at the top of the concrete, cork the bottle, there was a glass tube in the middle of the cork, and then sealed the cork with Vaseline immediately, as shown in Fig.1. the glass tube had a scale, with the decrease of the concrete volume, the liquid level in tube will drop, the dropped value was used to express the volume change of concrete.
The maximum diameter and grain diameter distribution of aggregate have no direct influence on shrinkage.
However, the aggregates with larger diameter and good grain diameter distribution can reduce the mixing water, which reduce the cement paste content, and leads to a smaller shrinkage for concrete.

Though FSP has been basically advanced as a grain refinement technique, it is a very attractive process for also fabricating composites.
Also results revels that with the increase in sinteringtemperature, the number of pores decreased and therate of grain growth apparently increased.However, this method requires alloy powders that are generally more expensive than bulk material, and involves complicated processes during the material fabrication.

To date, a large number of studies have been carried out to address corrosion issues and to improve the corrosion performance of Mg alloys [1,2].
All samples were mechanically ground for surface standardization with silicon carbide (SiC) papers with the decreasing of the grain size of the abrasive material down to 15 μm and further polished with aluminum oxide paper with the grain size down to 3 μm.

Fig. 1 – Grain size distribution of the different aggregates used.
However, limewater usually contains not more than 2 g/L of calcium hydroxide, that only guarantees a low consolidation effect, with a poor cementing action [2], unless it is applied in a high number of cycles.
According to previous studies [11], the carbonation of nanolime particles originate oriented crystal grains, which promote the agglomeration of particles, improving the cementing action, the cohesion of the particles and thus the mechanical strength of the treated surface.

In 1986, Babcock & Wilcox Company designed and built the portable, ultrasonic Nondestructive Oxide Thickness Inspection System (NOTIS®) for measuring oxide scale in the inner surface of tubes[3], which makes it possible to nondestructively assess a large number of tubes in a relatively short time.
Schematic representation of the tube configuration with oxide scale grown on steam side The alloy was assumed to be T22 (2¼Cr-1Mo), a ferritic alloy commonly used for boiler superheater and reheater tubes, which forms oxide scales in steam that typically consist of two main layers: an inner layer next to the alloy (usually fine-grained) consisting of Fe-Cr spinel [(Fe,Cr)3O4], and an outer layer which has a columnar-grained structure, and consists of essentially magnetite(Fe3O4).

To obtained the iron ore concentration, the tailings is usually handled by the methods of “magnetic roasting—low intensity magnetic separation” or flotation because the tailings have the disadvantage of low iron grade, lots of impurity and fine grain size.
Production practices and a large number of studies have shown that the best magnetic roasting temperature is about 750~850˚{TTP}730 C under conventional heating [12~14], and at this temperature range, the result of magnetic roasting is best and the productivity is higher.
In addition, because the molecule and atom of the minerals vibrate at high speed in microwave filed and the dielectric property of iron ore and Nb minerals are different from each other, there would be internal stress in the mineral grain [15, 16].

Lastly, the quality scalability or Signal to Noise Ratio (SNR) scalability is approached by two different methods, coarse grain scalability (CGS) and medium grain scalability (MGS).
The GOP 16 was used which also automatically define the number of I, and P frames.

Introduction Self-compacting concrete (SCC) is a new kind of high performance concrete materials, which can be close-grained molding in its own weight without vibration.
They were numbered from PC1 to PC5 according to the difference of SCC strength and reinforcement ratio.
Among them number PC1, number PC4, and number PC5 series beams had the same reinforcement ratio, and the experimental beams of number PC2, number PC3, and number PC4 had the same strength grade.
Test beams material parameters Beam number PC1 PC2 PC3 PC4 PC5 Concrete strength C20 C30 C30 C30 C40 b(mm)×h(mm) 105×153 102×153 104×155 100×158 100×159 fcu (N/mm2) 22.4 30.9 32.5 31.4 42.3 Ec(×104N/mm2) 2.67 3.03 3.03 3.03 3.31 Non-prestressed rebar 2Φ8+2Φ12 2Φ8+2Φ8 2Φ8+2Φ10 2Φ8+2Φ12 2Φ8+2Φ12 ρc (%) 2.43 1.59 1.97 2.43 2.43 Note: b, h, fcu and Ec are the physical width, physical height, compressive strength of cube test blocks and elastic modulus.
The characteristic parameters of experimental beams Beam number Pu /kN Mcr /kN·m My /kN·m Mu /kN·m Wm /mm Wmax /mm PC1 26 6.3 9.1 16.5 0.32 0.7 PC2 30 7.6 10.4 19.0 0.45 0.82 PC3 36 6.3 13.6 22.8 0.53 1.5 PC4 33 10.8 15.4 20.9 0.41 0.84 PC5 44 11.4 19.2 27.7 0.48 1.2 where , are the stiffness of applied not vertical load and applied grading vertical load; λ is a reflection of the test beam dynamic, static stiffness parameters.

Considering the opposite side of the phenomenon, a secured ignition, start-up and sustained combustion could only be obtained by providing a sufficiently high initial pressure and temperature around the propellant grain in the chamber, by means of an adequate ignition device, or igniter.
Most of these species are formed through thermal dissociation from a reduced number of main products, which are compulsory formed, regardless the dissociation, under the direct action of the law of masses.
From the action of the law of masses and simple stoichiometry the theoretical oxygen content in gram-atoms per unit mass of BP mixture AOt that would produces a complete combustion is equal to , (1) provided the number of sulfur gram-atoms is higher than half the number of potassium gram-atoms, . (2) This is the basic case.
When the theoretical oxygen content in the powder is not available, , (5) besides the main products of combustion given above a limited number of main products of incomplete combustion occur.
However, when the shift from the molar participations nj to the partial pressures pj is done, the additional variable π appears, as the still unknown ration between the total pressure and the total number of moles of gaseous products, , (7) where the total pressure pc is usually given and the total number of gaseous moles nG is still unknown.

Plot the histogram of gray image exported from profile filled with the color, gray level is between [0,255], the histogram is a discrete function , here,is the K-level gray degrees,is the number of the pixels with gray-scale level of.
The sharpness of the image is related with the number of pixels and resolution ratio; if pixels is a certain number of, the higher the resolution ratio, the image are more clear, and vice versa.
As Figure 4, by setting the coarse grid as 4 pixels, calculate the remainder of the total number of same pixels in the same region of this row, an integer used to divide the coarse grid; the remainder is used in the fine grid at the boundary
Figure 5 shows the total pixel number is 441×599, actual size is 221m×300m, proportional conversion factor R is 0.61475m/pixel, actual area of each pixel is 0.25083 m2.
The initial mining is started from the 2220m level, boundary pillar above the mine is about 30m, the ore body is divided into five excavation, the stope number ranges 1~5, respectively, seen as Figure 7a~7e.