Key Engineering Materials Vols. 474-476

Abstract: High-pressure becomes the high pressure unit design main consideration factor to compressive load capacity, security, efficiency, economic and manufacturing process of high-pressure equipment. This article proposes a new pressure piping according to the current high-voltage device development tendency and the future requirement. This new type of pressure pipe can be simplified for pipe casing model. Firstly we establish single, double and multilayer pressure piping model. We push out the multilayer pressure pipe stress formula according to stress situation of the analysis of the knowledge of mechanics of each model. We get this pressure piping withstand by the most intrinsic pressure enhance obviously under each layer within the radius of the cylinder reach the initial limitation of materials and other parameters of model are same through the comparison of the theoretical formula calculation with other general. Pressure pipeline calculated value. The multi-layer pressure piping system's circum radius are smaller than other piping with other pressure piping withstand the same most intrinsic pressure and the most interior radius are the same situation.

Abstract: Wireless sensor networks (WSNs) detect and monitor the outside physical state by the sensor nodes organizing automatically. Utilizing clustering algorithm to form hierarchical network topology is the common method which implements managing network and aggregating data in WSNs. Different from the previous clustering algorithms, this article proposes a clustering algorithm for WSNs based on distance and distribution to generate clusters considering residual energy of nods in WSNs with inhomogeneous distribution. The simulation result indicates that the algorithm can establish more balanceable clustering structure effectively and enhance the network life cycle obviously.

Abstract: Wood dyeing requires a non-subjective, repeatable method for determining the color testing and matching. Previously published method used human visual perception to determine the percent of dyestuffs. In this study, computer color matching technique was applied into the dyeing of fast growing wood for the imitation of precious wood species. The process includes measuring the color of wood samples, determining dyeset, preparing and measuring basic color samples, establishing a basic database, calculating and correcting recipes. The recipe of black walnut provided by the system was as follows: acid yellow 2G 0.19%, acid green 0.59%, acid red B 0.29%, with the chromatic difference 0.12%. It could be concluded that dyeing with computer color matching technique allows for a faster, less subjective and easily repeatable procedure that is superior to simple human visual perception.

Abstract: Flow in curved duct is different from that happens in straight pipeline. Affected by the curved duct curvature, the flow field in a curved duct is uneven. The flow in the curved duct suffers serious loss. Considering the flow field characteristic and engineering applications, the characteristic of the flow field in curved duct without guide plate and the curved duct with different guide plates have been studied based on the numerical results. The velocity distribution and unevenness on the outlet of the curved duct have been analyzed too. Then the best conditions for guide plates installed in curved duct are achieved.

Abstract: This paper presents the rehydration performance of binary binders made with dehydrated cement paste (DCP) and phosphogypsum (GP). DCP was obtained by thermal treatment of hardened cement pastes in which the initial water to cement ratio was 0.5. DCP we mixed with phosphogypsum (PG) to prepare the binary binders . The effect of PG on the physical and mechanical properties of the binary binders was investigated. Scanning electron microscope (SEM) was used to indentify the structural characteristics of the rehydration products. The results showed that the setting time was prolonged and the compressive strength increased slightly by mixing DCP with PG. Microstructural observations indicated that an remarkable amount of ettringite intergrows with the hydrated calcium silicate to form a network structure. Thus, the addition of phosphogypsum can not only utilize the industrial by-product, but enhances the hydraulic properties of the DCP.

Abstract: Thunderstorm downburst is a sort of outburst strong wind on or near the ground, and its wind field characteristics are significantly different from boundary layer winds. The study on its effect on the structures was relatively rare, nevertheless numerous structural failures around the world caused by thunderstorm were found. Computational fluid dynamics (CFD) was employed for this stationary downburst simulation, also the wind pressure distributions of the curved-roof in this flow had been surveyed by varying the parameters of the structure. The results show that the wind attack angle has significant effect on the wind pressure of curved-roof, so does the ratio of the rise to span. The predominant impacts of the ratio of wall height to span and the roof span were found at the windward side. Furthermore, by locating the roof beneath the downburst jet, the wind pressure distribution of the roof was also investigated to reveal the significant effects caused by vertical wind of downburst.

Abstract: On the basis of proposing the general ultrasonic testing system, this paper discusses the concept and the composite module of computer aided ultrasonic testing scheme planning. By the thought of ultrasonic testing part family and modularization parameterization design, and the paper induces the needed study to solute the theory question and each key technologies of ultrasonic testing scheme. Finally, it simply introduced the developed computer aided ultrasonic testing scheme planning system of rotational parts.

Abstract: A new unsymmetrical photochromic diarylethene 1-[2-cyanophenyl]-2-[(2-methyl-5-(4- methoxyphenyl)-3-thienyl)]perfluorocyclopentene (1a) was synthesized, its photochromic properties were examined, the result indicated that the Diarylethene 1a changed the color from colorless to purple upon irradiation with 297 nm UV light, in which absorption maxima were observed at 550 and 557 nm in hexane and PMMA film, respectively. This new photochromic system also exhibited remarkable fluorescence switching in hexane solution and remarkable optical storage character in PMMA film.

Abstract: A new photochromic diarylethene compound, 1-[2-methyl-3-benzothiophene]-2- [5-(3-chlorobenzene)-2-methyl-3-thienyl]perfluorocyclopentene(1a), was synthesized and its photochromism and photo-induced anisotropy was investigated. It showed good photochromism and functioned as an effective fluorescent photoswitch in solution. In hexane, the open-ring isomer of the diarylethene 1a exhibited relatively strong fluorescence at 417 nm when excited at 315 nm. In PMMA film, diarylethene 1a also showed good photochromism.

Abstract: This paper investigates a bus waiting problem quantitatively by building a mathematical model. The problem is when a passenger is between two stations, which station to choose is favorable for him to catch a bus Here, several related factors are discussed to explore their influences on the bus-waiting problem, including the original bus position, the average velocity of bus, the length between two bus stations, passenger’s position and his velocity. Finally, some important conclusions are drawn.