Micro structure Characteristics of Recycled Fine Aggregate and Its Concrete

The characteristics of recycled fine aggregate (RFA) and its concrete (RFAC) were analyzed by SEM, EDXA, XRD, Micro harness and nitrogen absorption. The results show that RFA is an artificial aggregate with complex compositions, certain hydration activity and high permeability. The mineral compositions of RFA include SiO2, CaCO3 and a small quantity of C2S, which has a certain hydration activity and can form hydration productions. The compaction rate of cement paste in RFAC is low because of pores in it. There is obvious interfacial transition zone (ITZ) between RFAC and cement paste, and its width is bigger than that in ordinary concrete. In addition, the values of micro hardness of the interfacial transition zone on both sides of RFA and cement paste are lower. The porous structure of the recycled fine aggregates and defects of ITZ are main reasons for big pores in RFAC, which has bad effect on impermeability of RFAC.     

A Double -edge Sword - -Elementary Analysis on the Overspread of Mass Culture to Architectural Culture

This article sets forth some phenomena occurring in the Architecture domain.It indicates that the Chinese Architectural circle is in the Stop-Suckle period of spirit.The reason for such phenomena enumerated above is analyzed from the aspects of particularity of the era and cultural language circumstance,as well as the impact of mass-culture with the emphasis on the effect of Mass culture.Analysis on the advantage and disadvantage of the overspreading of Mass culture was carried out and it is pointed out that mass-culture overspreading into Architectural culture is a double-edge sword.It has good influence as well as bad one,there should be correct guide to the mass culture to avoid its unfavorable effect.     

Influence of compound retarders on the hydration process of FGD building gypsum and its retarding mechanism

The effect of compound retardant powder P on the hydration process,ion concentration in liuquid and supersaturation degree,and crystal morphology of dehydrate of FGD building gypsum is investigated.Furthormore,by using the SEM,its retarding mechanism is also studied.The results indicate that the addition of powder P retardant the early hydration of FGD building gypsum,which leads to delay of hydration heat evolution.It can also decrease the hydration ratio at early stage and prolong induction period of FGD building gypsum.Powder P has a major effect on the crystal morphology of dehydrate,moreover it enlarges crystal sizes.Retardation effect of powder P is worked by a variety of ways. The ionization of calcium ion from the hydroxyl carboxylic acid calcium salt definitely impedes the early dissolution of hemihydrate FGD building gypsum, delay the formation of nucleus.Also the selective absorption of groups composed of carboxyl and hydroxyl inhibits the growth of nucleus.Moreover the protein also plays a colloid coated role for gypsum,inhibiting the growth of nucleus.     

Hydration Kinetics of Cement based Materials With P2O5 Incorporated

By means of SEM, XRD and calorimeter C 80Ⅱ, the hydration characteristics and hydration kinetics of cement based materials with and without P2O5 incorporated were investigated. It is found that the amount and size of hydration products incorporated with P2O5 were decreased dramatically. When 3.5% P2O5 was added in cement, total amount of hydration heat was decreased by 32.6% and initial and final setting were delayed by 1.10 h and 12.54 h respectively. In terms of mechanism analysis, P2O5 had little impact on cement hydration mechanism, and accelerating stage was controlled by chemical reaction, decreasing stage controlled by both chemical and diffusion reaction while stabilizing stage controlled by diffusion alone. The hydration resistance in both accelerating and decreasing stage was elevated while decreased in stabilizing stage. The activation energy in both accelerating and decreasing stage were reduced and increased in stabilizing stage. P2O5 was favorable to hydration of C3A yet retarded hydration of C3S and C2S.     

Study on Influence of Mineral Admixture on Chloride Ion Penetration and Diffusion in Concrete

In this paper, the influences of different kinds and different amount of mineral admixture to Cl-penetration and diffusion in concrete are studied. The results of experiment show that separate addition of mineral admixture (ground fly ash, slag fines, silica fume) into concrete can improve its resistance to chloride ion penetration and diffusion. Furthermore,the effect of silica fume is the best, fly ash second, and then follows slag fines. Mechanism analysis shows that the pozzolanic effect of mineral admixture improves the interface between the cement and aggregate in concrete, reduces the total porosity, makes pores more smaller, on the other hand it increases the Cl-consolidation capability of concrete with low alkaline C-S-H gel produced. So the resistance to chloride ion penetration of concrete is improved.     

Influence of Macromolecule-type Retarders on the Hydration and Microstructure of Hardened Paste

Influence of one macromolecule-type retarder bone glue on the setting time, strength, ion concentration in liquid phase and supersaturation degree, crystal morphology of dehydrate and microstructure of hardened paste of building gypsum is investigated. Furthermore, internal cause of strength loss of building gypsum with addition of retarder is analyzed, The results indicate that bone glue could retard the hydration of building gypsum markedly, but its negative influence on the strength of building gypsum is far lower than that of low molecule-type retarders. Bone glue has a minor effect on crystal morphology of dehydrate and porosity of hardened paste, but it causes the large crystal size and coarsening of pore size distribution of hardened gypsum paste, which is the very intrinsic reason of strength loss of building gypsum.     

Influence of Monocylic Aromatic High Range Water reducer on Hydration and Microstructure of Cement Pastes

The influences of the monocyclic aromatic high range water reducers on cement hydration were evaluated from four factors, such as hydration heat, hydration products, pore structure, microstructures of cement pastes. With measurement of hydration heat by the TAM Ai, it was found that monocyclic aromatic high range water reducer may delay early hydration and significantly decreased early hydration heat. And the monocyclic aromatic high range water reducers tended to increase porosity and pore volume of cement pastes with MRI analysis, while pore size distribution did not change remarkably. With analysis of XRD、TG DTA and SEM, it was shown that the monocyclic aromatic high range water reducers could restrain the production of Ca(OH)2 and Hydrated Calcium Silicates in the hydration process without affecting the end products, and refine the hydration products, such as Ca(OH)2, C S H gel and ettringite crystals.     

Cementation Effect with Cement during Cold In Place Recycling System of Asphalt Pavement

Different kinds of structures of RAP and different contents of cement were prepared. By means of standard compaction test, unconfined compressive strength, water stability, modulus and SEM test, the cementation effect with cement was studied. It was shown that the maximum dry density of RAP mixture rose from 1.91g/cm3 to 2.00g/cm3 with the increase of cement content when A/S was 0.4. The maximum dry density of RAP mixture would rise when adding more asphalt. The unconfined compressive strength rose from 1.48MPa to 2.63 MPa and then down to 2.28MPa when cement content was 6%. The best property could be got when A/S was 0.4 and the cement content was 6% with 9.5% water. The compressive strength of RAP mixture declined after it was cured in water for 24 h, but it had the same tendency with those of which had not been maintained in water. And it is also found that RAP does not obtain better stabilities in high temperature with modular test. From SEM test, it is shown that ettringite and C S H interlace and form the netted structure, and the aggregate would be enwrapped to increase the strength.     

The influence of retarders in the hydration process of phosphogypsum

The influence of retarders on the hydration process of phosphogypsum is investigated by determining setting time,intensity of hardened anhydrite,hydration rate,hydration temperature increase and the degree of solution supersaturation in combination with observing by scanning electron microscope. The results indicate that S〖JP+5〗G-10 and citric acid retarder can adapt to phosphogypsum well; pH value has a great influence on the retarding effect,5.1 and 6.0 are the best pH values for the effect of S〖JP+5〗G-10 and citric acid in plaster of phosphogypsum respectively. However,citric acid dosage should not exceed 0.1% or the amount of doped-SG-10 should not more than 0.2%. Both S〖JP+5〗G-10 and citric acid lead to a delay in the hydration heat evolution and significantly decrease the hydration ratio in the early stage and the ratio of recede limited in the final hydration.It can also partly change the hydration kinetics process of phosphogypsum at the same time. Initial liquid concentration and over-saturation of phosphogypsum are less than the blank sample after adding retarder,while liquid phase ion concentration and decreased ratio of over-saturation simultaneously are sharply depressed in the hydration reaction process. S〖JP+5〗G-10 causes the large crystal sizes,but it has a minor effect on the crystal morphology of dehydrate. Adding citric acid result in a large influence on the dehydrated crystal morphology of phosphogypsum.     

Intelligent Sliding-mode Control of Switched Reluctance Motor

Base finite element solution for the calculations of flux and torque of Switched Reluctance Motor, the state equation of SRM is thus educed. In addition, according to the fact that it is difficult to attain the ideal effect with the regulatory linear control method because of the double salient pole SRM structure of stator and rotor, fuzzy control is proposed and used in the sliding mode control to form a intelligent sliding mode control. We emphasize the introduction of the design method of the intelligent sliding mode control and present the control diagram. The simulation results show that the method of intelligent sliding mode Variable Structure Control is simple, with good dynamic performance and robust property.     

Resistivity Method for Monitoring the Early Age Pore Structure Evolution of Cement Paste

The changes of electrical resistivity with time of cement pastes with water to cement ratio of 0.23, 0.35 and 0.53 were in situ continuously monitored by using electrodeless resistivity apparatus. Isothermal conduction calorimeter was also used to measure the hydration degree. The quantitative relationship between electrical resistivity evolution of paste and development of pore structure was proposed during hydration process. The results show that four stages (dissolution, induction, acceleration and deceleration) are identified according to the characteristics of electrical resistivity and its differential resistivity curves. In addition, a lower water to cement ratio shows a smaller capillary porosity and constriction factor as well as a higher tortuosity factor, resulting in a higher electrical resistivity of bulk paste, and the reverse phenomenon is observed with the electrical resistivity of pore solution.     

Mechanical and Chloride Diffusion Behavior of Kaolinite Clay Modified Cement-Based Material

The effects of kaolinite clay on the microstructure (pore structure, internal structure) and mechanical properties (workability, early-age and long-term flexural strength, chloride diffusion property) of the cementitious composites were tested. It is shown that the addition of clay improves the micro-pore structure in the cement paste and limits the introduction of chloride ions. As a result, it is suggested that the kaolinite clay would act as both filler and accelerator of cement hydration. Compared with the control specimen, the flexural strength of cement paste with 1% kaolinite clay increased by 30.41%, 39.04%, 36.27% and 38.32% at 1, 3, 7 and 90 curing ages, respectively. The 28-day flexural strength increased slightly. It is observed that the clay modified cement mortar has lower chloride diffusion coefficient values compared to the plain mortar, and the 28-day DCl of cement mortar decreased by 53.03% with 5% clay. Compared with the controlled sample, the increase in compressive strength and the reduction in chloride diffusion coefficient of the concrete with 5% clay addition is 28.4% and 18.87% respectively. The chloride diffusion coefficient of concrete decreases with the amount of clay addition exponentially. The 28-day compressive strength increases linearly with the chloride diffusion coefficient of the concrete.     

Some Discussion On the Calculation of the Discrete Fourier Transform(DFT)

In the field of signal analyies for time frequency, the DFT is a familiar term. Especially,when its efficient algorithm FFT given, the other operations in signal analyses are also usually translated to DFT as soon as possible so as to enhance the calculating speed. But in our exploning the virtual instrument for time frequency analyzing, two sorts of formulas to calculate DFT and its inverse transform (IDFT) are found. These results are in different value of operation from different signal analysts or from different instruments for time frequency analyzing, their physical meaning are also not clear enough.The period extent theory some previous document based on when defined DFT is firstly expatiated. Then, separately with future defining coefficient method and analogy evolvement method, the authors argue that, based on the period extent theory, it is more rational to calculate DFT with the formula given. A shortage is pointed out and corrected is appeared in some previous documents when having given the formula of DFT. The improper view is also clarified that the reason why there are two sorts of formulas is make by custom.The rationality of the authors view with three examples is visually verified in the end.     

Effect of organic carbon on nitrogen removal and microbial community in the completely autotrophic nitrogen removal process

Different synthetic wastewaters are used to analyze the effect of organic carbon on the nitrogen removal and microbial community in the completely autotrophic nitrogen removal process. Results show that the nitrogen removal performance is improved by control of DO at a reasonable C/N ratio. The NH +4-N is removed in several ways. When the influent without any organic carbon, the most of ammonium is removed in nitrification-ANAMMOX metabolic pathway; the contribution of nitrification-ANAMMOX decreases, while the conventional nitrification-denitrification process enhanced with the addition of organic carbon. PCR-DGGE and statistical analyses show that the microbial diversity in SBBR reactor fed with organic wastewater is more abundant than it fed with inorganic wastewater,and this exhibits obvious in the biofilm, which also indicate that it helps to format the aerobic-anaerobic microenvironment,so nitrogen can be removed in different ways in one reactor.     

Pyrolysis and kinetics characteristics of typical crop biomasses

It is necessary to study the process of biomass pyrolysis in order to use it efficiently. The pyrolysis characteristics and pyrolysis kinetics parameters of four typical crop biomasses (rice shell, rice haulm, corn core and corn haulm) are studied using thermo gravimetric analysis (TGA). Results indicate that biomass pyrolysis process may be divided into three stages: the preheating dry stage, the volatile matter separation stage, and the carbonization stage. Thermal weight loss mainly occurs at the volatile matter separation stage. Because the biomass has higher volatile matter and lower fixed carbon, its pyrolysis is quite thorough. The rank order of the synthesized pyrolysis characteristic index is rice shell, corn core, rice haulm, and corn haulm. At the same time, the pyrolysis process can be divided into two stages. The volatile matter separates out fiercely in the initial pyrolysis period with an obvious peak and lower activation energy, while there is no obvious peak and the activation energy reaches higher in the later pyrolysis period. For coal residue, because of its lower volatile matter and higher ash, the ash hinders the volatile matter proliferation to a certain extent in the initial pyrolysis period, causing difficulty in separation of the volatile matter. Secondary volatile matter separations concurrently happen near the end of the pyrolysis period. The pyrolysis characteristics of sludge is similar to biomass. In addition, the pyrolysis reaction follows the R2 model for rice shell and corncob in the first prolysis stage. The pyrolysis reaction is in line with a response model for the other biomasses and the rest various stages. The three dimensional spherical symmetry subordinates to the proliferation mechanism for coal residue in the initial pyrolysis stage. The pyrolysis reaction is governed by the liquefaction reaction. The progression of chemical reaction is 3/2 in the later pyrolysis stage. The sludge adheres to the simple reaction order mechanism.     

Analysis on the Temperature-control Effect of the Particle Improved Roadbed in Qinghai-Tibet Railway

Based on the observerd ground-temperature data of the particle improved roadbed in Beiluhe test site of Qinghai-Tibet railway, the characteristics of the ground temperature to the particle improved roadbed and its temperature-control effect are analyzed ,and compared with other frozen soil protecting means. The result indicated that the ground temperature of the particle improved roadbed changes with the seasons,and its characteristics present as a sinusoidal curve. Compared with the normal roadbed, the paticle improved roadbed has cooling roadbed and the effect of protecting frozen soil in mean annual ground temperature. Compared with the normal duct-ventilation embankment, the cooling effect of the particle improved roadbed in cold season is less than that of the duct-ventilation roadbed,and the thermal shield effect is better than that of the particle improved roadbed in warm season. The ground temperature curve has the better tendency of the frozen soil protection. It is an active means of frozen soil protecton.     

Effect of Stitching on the In-plane Tensile Strength of Stitched Composite Laminates

Some additional effects of stitching on the in-plane mechanical properties of composite laminate is introduced while it was used to improve the interlaminar of plane mechanical properties of the composite laminate. The paper investigates the effect of stitching on in-plane tensile strength of composite laminates. The results show that the effect of stitching is dependent on the stitching parameters. The in-plane tensile strength of laminates is degraded with the decreasing of stitching space and step and increasing diameter of stitching thread. It is found that the initial damage of laminate increased with increasing of stitching parameters such as stitching density. This causes the decrease in the in-plane strength of composite laminate.     

Effect of Mischmetal Additions on the Ignition Temperature ofMolten ZM5 Magnesium Alloy

Magnesium alloy is prone to burning during its melting and casting in air, which is a major factor in obstructing its application. Fluxes and cover gases are currently used for the melting and production processes, and semi solid thixocasting is also used to lower the operation temperature, but there still remain many problems. Alloying is a promising method of preventing Mg from burning. The effect of mischmetal additions on the ignition temperature of ZM5 Mg alloy was investigated and compared with that of pure rare earths. It is shown that an addition of 0.12 % mischmetal can greatly heighten the ignition point and such an alloy can be widely applied.     

Selecting Enterprises for Swap of Debt to Equity and Mechanism Design

The swap of debt to equity in state owned enterprises is dynamic game processes of conflicting and struggling among the concerned parties for the maximization of its payoffs and the seeking of domination for financial resources, and can be accomplished successfully when its being brought into effect is going to be propitious to the concerned parties. This paper analyzes the problem of selecting enterprises for swap of debt to equity under the frame of information economics theory, and argues that the selection of enterprises for swap of debt to equity is a problem of mechanism design. As the expected utility function of enterprises is analyzed and Asset Management Corporations adopts a series of measures to deal with it according to analysis, a policy frame will have been constructed.     

The Effect of the Components of VAE Latex Modified Cementitious Compound Waterproofing Coating on Its Properties

In this paper the effect of the components of VAE latex modified cementitious waterproofing coating on its properties is studied. The results show that the tensile strength, bond strength and water resistance of the compound water proofing coating increase greatly in comparison with those of the coating without addition of cement. This compound coating is a new type of waterproofing material with excellent performance.