Key Engineering Materials Vols. 467-469

Abstract: Mechanical parameter analysis is a complicated issue since it is influenced by many factors. Closely related with the influencing factors of compressibility coefficients of rock material (sandstone), this article first introduces the way to process partial least square regression (PLSR) analysis. The process of carrying out PLSR is divided into six steps as for analysis and prediction of the regression model, which are data preparation, principle collection, regression model for first principle component, secondary principle analysis, establishment of final regression model and number determination of principal component l. And then introduces PLSR for application of analysis and prediction of compressibility coefficients with 30 experiment samples. Seven prediction samples are carried out by PLSR with the training process of 30 samples. The result shows PLSR has good accuracy in prediction under the condition that the model is properly deprived based on certain experimental samples. Finally, some conclusions are made for further study on both mechanical parameters and partial least square regression method.

Abstract: Wireless sensors are increasingly adopted in mechanical systems to acquire and wirelessly transmit sensed information for machine condition monitoring. For wireless sensors on spindle, the reliability of the sensors system at high rotary speed is the key factor to guarantee the validity of monitoring. How to identify sensor failure accurately and timely is essential to enhance reliability of monitoring system. To address this issue, a novel method based on the BNs was presented to distinguish sensor failure from other transmission errors. The method described causal relationships of factors inducing sensor failure by graph theory and deduced sensor failure by Bayesian statistical techniques. Experiments carried on NC machining center prove the validity of this approach.

Abstract: A new method was proposed to determine the size and location of the internal deficiency of the standing trees using the acoustic velocity of the ultrasonic, and the method was explained in specific on the process of how to put it into practice. Through the comparison of the experiment on defective Dahurian Larch between the ultrasonography and the Resistance Drilling, the results proved that the method was available and concluded the accuracy of this method when testing deficiency. Meanwhile, the average transmission velocity of the ultrasonic in Dahurian Larch was obtained through large amount of experimental data.

Abstract: The plastic sheet forming technique is simple and easy to realize, that is why, it is widely used for packaging commodities. Similarly, in In-Mold-Decoration (IMD) molding technology, due to the complex geometry of the membrane and the high requirement of the dimensional accuracy, geometric design and molding technique for the product should be focused on controlling the thickness distribution of shell or membrance plastic products in order to achieve high precision manufacturing. This paper started with analyzing the performance data of the plastic sheet molding material, using nonlinear finite element method and multi-physics coupling method to simulate the plastic sheet forming process, and the result gives the required parameters for product design and quality control. For the thickness deviation, the experimental testing shows that the maximum discrepancy between the simulation and actual result is less than15%. The research proved that computer simulation can contribute to control the inhomogeneity of the shell or membrane so as to improve the design and the quality of manufacturing.

Abstract: In modern forest measurement situation that lack of good accuracy, in order to meet the needs of precision forestry and realize the precise measurement of every single tree, this paper introduces an automate technology and software platform of forest measurement in fixed sample. This technology and method can give full play to the precision total station angle measurement range function and PDA data processing and storage function, which are based on the communication system programming development of total station and PDA with WinCE. This automation technology are used to gain 3d coordinate, tree height, DBH and crown of trunks, it can both realize the automation process of testing trees and ensure the accuracy of measurement, improving the work efficiency greatly.

Abstract: Both low-cycle fatigue and high-cycle fatigue exist during torsional vibrations, but the impact of high-cycle fatigue has rarely been considered. In this paper, a torsional fatigue life analyzing method used for torsional vibration of turbo-generator shafts has been developed based on Manson-Coffin equation and high-cycle fatigue theory. The method has been used to estimate the torsional fatigue life in the most dangerous section of the shafts in a power plant. The cumulative torsional fatigue damage under two-phase short circuit simulation has been predicted.

Abstract: First the principle of BP Net Neural Works was introduced, and the Region Classification model based on BP Net Neural Works of Forestry Ecological-Economy System was built. Then the City Forestry Ecological-Economy System of Sichuan province was classified with the model, moreover it was simulated with platform of MATLAB, and the Classification result was perfect, its Classification precision could arrive at above 90%.The emulator result indicated that the BP Net Neural Works pass through training could recognize region character of the Forestry Ecological-Economy System effectively,and could realize auto classification of the Forestry Ecological-Economy System.

Abstract: By the impact of coal mining, coal floor will produce distortion and damage, and make the damage zone which may result in water inrush from the floor of coal seam. CT technology with DC electricity is used to analyze two-dimensional point source current field by employing the forward calculation, inverse iteration, model correction and other methods. On the basis, inverted resistivity image of the detecting zone is obtained, which can help to determine damage law and damage depth of coal seam floor. And then the possibility of water inrush from the coal floor is analyzed. Industry practice shows that the research results are credible and can play an important guiding role in the controlling of water inrush.

Abstract: We have developed a cell-seeded 3-dimension constructs tissue regeneration and used it successfully to repair defects of bone and cartilage. However, improvements of mechanical strength were demanded for clinical usage of reconstruction of gastrointestinal tracts. Rat model was used to evaluate whether PLGA constructs seeded with smooth muscle cells (SMC) could withstand suturing and anastomotic strength. Macrscopic, histological, and immunohistochemical assessment were performed to evaluate regeneration of stomach up to 14 days. SMC-seeded constructs show sufficient strength for suturing, no dehiscence, and better biocompatibility for clinical use, although further examination will be necessary to create a functional digestive tract.

Abstract: The trans-critical CO2 cycle usually involves a regenerative process. The regenerative process used in the trans-critical CO2 cycle is analyzed in this paper. The cycle with regeneration and without regeneration had been compared. The circumstance for the regenerative process set in the trans-critical CO2 cycle is given. The impact regeneration made on the performance of the system in difference operating conditions is also discussed in this article.