Abstract: The concrete is a solid and porous composite materials, when the concrete exposure to moisture environment for a long-term, the pore water will penetrate into concrete cause hydration products leaching. Leaching of calcium ions increase in porosity and resulting in harmful ions ingress into concrete to reduce strength and durability of concrete. The purpose of this study is to evaluate the effect of water-binder ratio on calcium ion leaching behavior of cement-based material. The ammonium nitrate solution was used to accelerate leaching process. Leaching duration was 56 days, 91 days and 140 days, respectively. The leaching depth and compressive strength were measured. The results showed that leaching resistance increased with a decrease in water/binder ratio. The leaching depth showed that leaching behavior of the specimens without minerals admixtures can be divided into two stages, the first stage was leaching of calcium hydroxide and than the C-S-H gel were leaching.
Abstract: The molten salt heat receiver performance of a solar power tower plant is analyzed in this paper. The numerical model of the heterogeneous heat flux boundary of which a half of the single heat receiver is heating and the other half of that is adiabatic heating, and of the heat convection and heat transfer in the molten salt heat receiver on condition of the convective heat loss and the radiation loss boundary conditions is established. In the numerical model, the wall heat conduction and variable property of the molten salt are considered as well as the roughness of the wall. The flow velocity, the temperature distribution and the heat transfer characteristics of the molten salt heat receiver under the conditions of high temperature and high heat flux are presented as important basis for the design and the operation control of the molten salt heat receiver.
Abstract: In collaborative design, it is very important to effectively express complex parts information. In this paper, the several expressions for parts information are analyzed, the expressions are parts information expressions of geometry-oriented model, the multi-view expressions of parts information, the exchange of parts information between heterogeneous systems, and share of parts information geographically distributed. And the expressions are used to describe the parts information.
Abstract: Influenza is a common acute viral disease that has caused massive harm to human, so a rapid pathogen-detecting method is required for monitoring the status of the disease. Quantum dots are promising emerging fluorescent probe for diagnostic assay. In this work, water soluble ZnO quantum dots were covalently conjugated to rabbit anti-chicken IgY antibody to prepare the quantum dots-linked secondary antibody. The conjugate was characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorescence spectrophotometer. Fluorescent quantum dots-based immunosorbent assay was conducted to determine the concentration of influenza B virus. We found that rabbit anti-chicken IgY antibody augmented its molecular weight while coupled to ZnO quantum dots, but the emission spectrum didn’t change. More importantly, the luminescence intensity of QDs correlated to viral concentration in a linear relationship. These results may suggest a potential new approach for quantifying virus, pathogenic bacteria and toxic molecule.
Abstract: The effective propagation constants of coherent elastic SH wave in composites with random distributed parallel cylindrical nanoholes in host material are studied. The surface elastic theory is used to consider the surface stress effects and to derive the nontraditional boundary condition on the surface of nanoholes. The plane wave expansion method is applied to obtain the scattering waves from the individual cylindrical nanohole. The multiple scattering effects are taken into consideration by the configuration averaging of random distributed scatterers. The effective velocity and attenuation of coherent SH wave are numerically evaluated. The influence of surface stress is discussed based on the numerical results.
Abstract: With the adoption of ABAQUS/Explicit as the simulation platform, a 3D finite element model has been established to simulate the stretch bending of square tube aluminum profile which is used as the door frame of fork lifter. Four characteristic points are put forward to evaluate the distortion of cross section during deformation, and the influence to distortion of cross section from some key parameters, such as bending radius and thickness of profile, is analyzed. An orthogonal experiment is designed to evaluate the influence to deformation from other forming parameters, including preload, fill rally and filling pressure which occurred in the stretch bending process. Then neural network based response surface method and genetic algorithm are used to optimize the parameters mentioned above. Finite element simulation proved that the optimized result is valuable to reduce the distortion of cross section of profile and improve formability.
Abstract: Two classification methods for fine recycled aggregate used in asphalt concrete were investigated in this paper, respectively classifying by fine recycled aggregate properties and asphalt concrete properties. When classifying by fine recycled aggregate properties, all test results of fine recycled aggregate properties can meet the technical requirements of China with obvious differences in quality. When classifying by asphalt concrete properties, fine recycled and natural aggregate was respectively used to prepare asphalt concrete with the same gradation, the same asphalt, the same limestone mineral filler and the same coarse natural aggregate. Some related properties of asphalt concrete were discussed to classify fine recycled aggregate. It is proposed in this paper that fine recycled aggregate should be classified into three types by asphalt concrete properties and the proposed classification criterion is given.
Abstract: The main purpose of this work was to study the applicability of an image texture analysis method, namely, the grey level co-occurrence matrix (GLCM) method for the examination of the smoothness of the images of a turned surface. The effect of the variation of the pixel pair spacing (pps) on the construction of the GLCM was also considered and then, contrast and homogeneity were calculated from the GLCMs which served as texture descriptors for the quality of the machined surface. Finally, the variation of these texture descriptors with cutting time was analyzed and compared with the variation of tool wear and surface roughness with cutting time.
Abstract: The application of High Strength Low Alloy (HSLA) steels has expanded to almost all fields viz. automobile industry, ship building, line pipe, pressure vessels, building construction, bridges, storage tanks. HSLA steels were developed primarily for the automotive industry to replace low-carbon steels in order to improve the strength-to-weight ratio and meet the need for higher-strength materials. Due to higher-strength and added excellent toughness and formability, demand for HSLA steel is increasing globally. With the increase of demand; other issues like the selection of filler grade and selection of suitable welding process for the joining of these steels have become very significant. This paper discusses the various issues regarding selection of suitable grade and selection of suitable welding process for joining of HSLA steels and issues concerning the structural integrity of HSLA steel welds.