Advanced Materials Research Vol. 905

Abstract: In this paper the authors establish the calculus expression of the volume flow rate for a new type of working machine that can work as pump, fan or low pressure compressor.The calculation of volumetric efficiency is established for a new type of machine.The results of the experimental research on the influence of the speed on the volumetric flow rate of the machine are exposed.

Abstract: The purpose of the paper is to demonstrate that the age of porous diffusers manufactured by ceramic, plastic or other porous materials declined. Following theoretical and experimental researches, the author built a new type of fine bubble generator whose nozzle plate is manufactured by spark erosion. The constructive solution of the fine bubble generator is presented; the scheme of the experimental stand developed at POLITEHNICA University of Bucharest is subsequently exposed. The final section of the paper presents the results of the experimental research, which are compared to data existing in specialty literature.

Abstract: We present a pilot study for the first time that microwave-induced thermoacoustic tomography (TAT) has the potential to detect osteoarthritis (OA) in the finger joints in vitro. In this study, we use rabbit hind feet to imitate humans finger joints, one rabbits hind feet was examined carefully by a TAT scanner, and the two-dimensional (2D) thermoacoustic images were reconstructed by the delay-and-sum algorithm. The difference of absorption coefficient of bone and articular cartilage has been displayed clearly in the reconstruction images.

Abstract: A design optimization approach of a solid propellant rocket motor is considered. A genetic algorithm (GA) optimization method has been used. The optimized solid rocket motor (SRM) is intended to use as a booster of a flight vehicle, and delivering a specific payload following a predefined prescribed trajectory. Sensitivity analysis of the optimized solution has been conducted using Monte Carlo method to evaluate the effect of uncertainties in design parameters. The results show that the proposed optimization approach was able to find the convergence of the optimal solution with highly acceptable value for conceptual design phase.

Abstract: For focusing airborne parallel translational variant SAR, an analytical imaging algorithm based on the extended Loffeld bistatic formula (ELBF) is proposed. With the bistatic geometry, point target (PT) position offsets to the transmitter track are expressed in terms of PT position offsets to the receiver track. Then phase terms of spectrum are divided into range and azimuth phase terms. The bistatic deformation (BD) term is compensated in 2-D frequency domain, and space variances of range and azimuth phase terms are eliminated by chirp scaling (CS) method and chirp z-transform (CZT) respectively. The proposed imaging algorithm is verified by simulations.

Abstract: In this paper, we start from the research on the radar simulation technology, adopt a method based on the 4D trajectory module simulation based on the analysis of the advanced technologies abroad and developing status at home. Following detailed descriptions combined with all the major modules, the integrated radar track simulation method is established. Research and implementation of the technology in the field of air traffic control has great practical significance.

Abstract: Radar signal processing often needs complex modulo operation. In order to achieve the integer complex array modulo operation, we discuss two integer complex modulus algorithm, the loop iteration method and the linear approximation method in this paper. The loop iteration method uses the idea of successive approximation. And the linear approximation method uses another approximation formula. Accuracy and efficiency of the two algorithms are compared and analyzed later. These two algorithms have been implemented and optimized in FPGA. Simulation and analysis results show that the loop iteration modulo is more suitable for a higher precision situation while linear approximation method is better for a time-critical situation.

Abstract: A novel fast algorithm for lndependent Component Analysis is introduced, which can be used for blind source separation and machine fault diagnosis feature extraction. It is shown how a neural network learning rule can be transformed into a fixed-point iteration, which provides an algorithm that is very simple, does not depend on any user-defined parameters, and is fast to converge to the most accurate solution allowed by the data. The purpose of this paper is to review the application of blind source separation in the machine fault diagnosis,including the following aspects: noise elimination and extraction of the weak signals,the separation of multi-fault sources,redundancy reduction,feature extraction and pattern classification based on independent component analysis. And its application in machine fault diagnosis is illustrated by the examples. In addition, some prospects about using blind source separation for machine fault diagnosis are discussed.

Abstract: Text document classification is content analysis task of the text document and then giving decision (or giving a prediction) whether this text document belongs to which group among given text document ones. There are many classification techniques such as decision method basing on Naive Bayer, decision tree, k-Nearest neighbor (KNN), neural network, Support Vector Machine (SVM) method. Among those techniques, SVM is considered the popular and powerful one, especially, it is suitable to huge and multidimensional data classification. Text document classification with characteristics of very huge dimensional numbers and selecting features before classifying impact the classification results. Support Vector Machine is a very effective method in this field. This article studies Support Vector Machine and applies it in the problem of text document classification. The study shows that Support Vector Machine method with choosing features by singular value decomposition (SVD) method is better than other methods and decision tree.

Abstract: GRIB code has good features: such as self-description, flexibility and extensibility, and is widely applied in the description, storage and transmission of meteorological data. Wind filed streamline demonstrates the direction and trend of wind to some extent. For visualization of wind field streamline using GRIB Meteorological data, GRIB data are firstly converted into grid data using inverse distance weighted interpolation method, and then this paper proposes an algorithm for determining and tracking the points on streamline by streamline vector value evaluation and direction detection. Finally, the chart of wind field streamline is drawn using real GRIB data. The results have proved that the designed algorithm is feasible and the chart meets the needs of users.