Advanced Materials Research Vols. 482-484

Abstract: During the severe accident in nuclear power plant (NPP), large amounts of fission products are released with accident progression, including In-vessel and Ex-vessel release. Thus, the Source term evaluation is essential for the probability risk assessment (PRA) and is still imperative for the licensing and operation of NPPs. Iodine is one of the most reactive fission products emitting in a large amount to containment and have a severe impact on health and sounding environment. Therefore, the iodine source term has been evaluated for 1000MW Reactor, by considering the TMI-2 as the reference reactor. The modeling and simulation of released radioactivity have been carried out by developing a MATLAB computer-based program. For post 1100 operation days, with the instantaneous release of radioactivity to the containment has been studied under LOCA. The dependency of radioiodine on ventilation exhaust rates has been studied in normal, emergency and isolation mode of containment. Moreover, the containment retention factor is also evaluated in said states of containment.

Abstract: All-weather solar water heater, which makes the most use of direct and indirect solar, can provide hot water in all weather. Heating at the day’s highest temperature enhances greatly the energy efficient ratio，Cooling at the day’s lowest temperature enhances greatly refrigeration coefficient to save electric energy. In summer, it is able to supply hot water and relevant cooling, avoiding heat pollution and cooling loss. In winter, it is able to supply hot water and relevant heating. The water cycle system which is adapted to store and supply of heating and cooling, reduces the area of solar collector and links of heat exchanging to reduce cost. All-weather solar water heater with advantages such as high conversion efficiency of solar energy and heat energy, initial cost, operating cost and power saving which are better than traditional solar water heater of the same volume, has a great potential for future application.

Abstract: This paper presents a 3D FEM computation model for a power transformer structure, where several conductor disks in series are used to constitute each winding, this is different from the normal cylindrical shape models. Base on such model the simulated ohmic losses in windings can be the same as that of measured. Then the stray magnetic fields in the transformer, the eddy losses in tank, the effect of magnetic shunts on tank losses are all studied, the calculated decrease of eddy losses in tank when magnetic shunts are properly used is compared with that of measured, they are coincide in some degree, which imply this model is reasonable for the simulation

Abstract: TiN protective coating was prepared on NdFeB by DC magnetron sputtering to improve the corrosion resistance and scratch resistance of the magnetic. During deposition, the nitrogen/argon mixture gas was introduced into the chamber with the nitrogen partial pressure at 20 % and 10 % and the bias of 200 V was applied to subtract, respectively. At a lower nitrogen partial pressure of 10%, TiN coating was composed of many particles with an irregular shape. With increasing the nitrogen pressure to 20%, composing particles become small and show as the regular trihedron shape. All TiN coatings have a cubic structure. The bias makes the depositing TiN coating denser and preferential growth become no obvious. By the nitrogen partial pressure of 20 % and bias of 200 V, the dense TiN coating has best corrosion resistance and excellent wear resistance.

Abstract: Objective The present study aimed to introduce the manufracture process of the suction tube special for the Piezoelectric surgery and explore its effect in the surgical extraction of impacted lower third molars. Methods The sample consisted of 114 patients undergoing surgical third molar removal. The special suction tube was periodically used during the whole process of Piezoelectric surgery. Results The suction tube can quickly clear the mouth, essentially vacuuming up the excess liquid, splatter particles and aerosol away from the area of concern, offering a clear surgical field for the dentists. Meanwhile, the tube can be used as a retractor to raise the mucoperiosteum flap, to expose the operation field more clearly. Conclusion The suction tube special for the Piezoelectric surgery can be a simple and practical tool for the Piezoelectric surgery.

Abstract: According to mechanical characteristics of space truss structure, the dynamic characteristics of boom system of crawler crane in derricking condition are simulated based on positional FEM. FEM simplified analytical method is established basing on engineering algorithm, only a few units and small amount of calculation are needed when using variable cross-section beam to simulate boom integral structure. The dynamic response time curves of boom system in derricking conditions are obtained, and compared with the existing literature. This further confirms the simplified model is feasible in theory and easy to realize in engineering, it also shows that positional FEM is feasible in dynamic analysis of complex structure.

Abstract: A kind of flexible, conductive polypyrrole–coated polyurethane (PPy/PU) fibers was fabricated by controlled chemical polymerization and its strain sensing ability was evaluated. The as-prepared fibers possessed high conductivity with a maximum value of 10^-1 (Ω•cm)^-1, and highly elastic nature of the PU matrix. It is further found that dense PPy layer was covered uniformly onto PU fiber surface, and an interpenetrating interface and strong hydrogen bonding interaction could be observed, which greatly benefited their high structural stability. More importantly, the composite fibers exhibited a wide strain deformation range up to 250% and high strain sensitivity of over 20 (at the large strain of 50%), and good reversible resistance response on cyclic force loading, which would open a high opportunity for fabricating strain sensing material in large volume for future smart device applications.

Abstract: The buffering properties of honeycomb material are analyzed in the presented work. Theoretical analysis based on energy method is first presented, the buffering process of honeycomb material can be divided into three phases, honeycomb material can be equivalent to orthotropic material and the equivalent material properties are given. Being good at soil mechanics, Abaqus can simulate lunar soil very well. Using a constitutive model for honeycomb material, which is a built-in user material model, the presented work developed a honeycomb material simulation model and verified with a practical example. Now we can analysis the entire landing buffer process in Abaqus, which is a complement to existing analysis processes.

Abstract: To study the relationship among the height amplitude of surface roughness , assessed area and assessed direction, the height amplitudes SRa, SRq, SRsk and SRku based on area-direction character are defined in the paper. And on the foundation of these parameters, relative assessed area indexes, assessed direction indexes and assessed total indexes are established. SRa, SRq, SRsk and SRku are the natural extension of 2D height amplitudes Ra, Rq, Rsk and Rku. They are different from 3D height amplitudes Sa, Sq, Ssk and Sku. They provide an evidence to study the quantitative relationship among surface roughness, assessed area and assessed direction. Relative assessed area indexes, assessed direction indexes and assessed total indexes can be used to assess the distribution situation of height amplitudes of surface roughness related to area, direction and entireness.

Abstract: After a short introduction about aerodynamic noise generation mechanisms, frequency and velocity characteristics of interior and exterior aerodynamic noise for a production automobile under different wind speeds are investigated through 1:1 aeroacoustic wind tunnel tests. The results show that: Both for the interior and exterior aerodynamic noise, the frequency characteristics keep almost the same as wind speed goes up. The linear OASPL for the interior aerodynamic noise increases at about 4.5th power of wind speed, for the pseudo noise on the vehicle body surface at 4.1th power, for the exterior noise out-of-flow also at 4.1th power. However, the A-weighted OASPL for the interior aerodynamic noise increases at about 5.2th power of wind speed, for the exterior noise out-of-flow at 6.0th power.