Over the past decade, wavelets provided a powerful and flexible set of tools for handling fundamental problems in science and engineering. Wavelet analyses are being used for solving problems in different engineering ...Over the past decade, wavelets provided a powerful and flexible set of tools for handling fundamental problems in science and engineering. Wavelet analyses are being used for solving problems in different engineering areas like audio de-noising, signal compression, object detection, image decomposition, speech recognition etc. Wavelet analysis employs orthonormal as well as non-orthonornal functions. This research investigates the effectiveness of wavelet analysis in detecting defects in underground steel pipe networks. Continuous Wavelet Transforms （CWT） has been performed on the received signals of cylindrical guided waves. Cylindrical Guided waves are generated and propagated through the pipe wall boundaries in a pitch-catch system. Piezo-electric transducers are used to generate as well as receive guided waves. Several mother wavelet functions such as Daubechies, Symlet, Coiflet and Meyer have been used for the Continuous Wavelet Transform to investigate the most suitable function for defect detection. This research also investigates the effect of surrounding soil on wavelet transforms for different mother wavelet functions.展开更多
This work deals with an application in parametric modeling of problems regarding pipelines buried in static system, written in C＋＋ using ObjectARX functions. The application is fully integrated with AutoCAD through ...This work deals with an application in parametric modeling of problems regarding pipelines buried in static system, written in C＋＋ using ObjectARX functions. The application is fully integrated with AutoCAD through saproms.dll and saproms.arx libraries where the stages of pre-processing, processing and post-processing are done in AutoCAD sotlware environment itself without having to export data to another processing environment. The analysis processing is done by functions whose algorithms are based on the solution of the coupling between the FEM （finite element method） and the BEM （boundary element method）. The representation of the homogeneous pipeline is made by the FEM using a finite element in the form of a cylindrical panel called CYS （cylindrical shell）, developed from the homogeneous isotropic model proposed initially by Djoudi Bahai, who uses the philosophy of the assumed deformation model （assumed strain based model）. The soil is taken to be a continuum infinite or semi-infinite elastic solid patterned by BEM where special boundary elements are proposed with curved surface or curved edges to represent the soil-structure interaction mainly in the areas of contact with the pipeline.展开更多
This paper presents a new sonochemistry reactor, which consists of a cylindrical tube with a certain length and piezoelectric transducers at tube’s end with the longitudinal vibration. The tube can effectively transf...This paper presents a new sonochemistry reactor, which consists of a cylindrical tube with a certain length and piezoelectric transducers at tube’s end with the longitudinal vibration. The tube can effectively transform the longitudinal vibration into the radial vibration and thereby generates ultrasound. Furthermore, ultrasound can be focused to form high-intensity ultrasonic field inside tube. The reactor boasts of simple structure and its whole vessel wall can radiate ultrasound so that the electroacoustic transfer efficiency is high. The focused ultrasonic field provides good condition for sonochemical reaction. The length of the reactor can be up to 2 meters, and liquids can pass through it continuously, so it can be widely applied in liquid processing such as sonochemistry.展开更多
This paper presents a combination of the hybrid spectral collocation technique and the spectral homotopy analysis method(SHAM for short) for solving the nonlinear boundary value problem(BVP for short) for the electroh...This paper presents a combination of the hybrid spectral collocation technique and the spectral homotopy analysis method(SHAM for short) for solving the nonlinear boundary value problem(BVP for short) for the electrohydrodynamic flow of a fluid in an ion drag configuration in a circular cylindrical conduit. The accuracy of the present solution is found to be in excellent agreement with the previously published solution. The authors use an averaged residual error to find the optimal convergence-control parameters. Comparisons are made between SHAM generated results, results from literature and Matlab ode45 generated results, and good agreement is observed.展开更多
文摘Over the past decade, wavelets provided a powerful and flexible set of tools for handling fundamental problems in science and engineering. Wavelet analyses are being used for solving problems in different engineering areas like audio de-noising, signal compression, object detection, image decomposition, speech recognition etc. Wavelet analysis employs orthonormal as well as non-orthonornal functions. This research investigates the effectiveness of wavelet analysis in detecting defects in underground steel pipe networks. Continuous Wavelet Transforms （CWT） has been performed on the received signals of cylindrical guided waves. Cylindrical Guided waves are generated and propagated through the pipe wall boundaries in a pitch-catch system. Piezo-electric transducers are used to generate as well as receive guided waves. Several mother wavelet functions such as Daubechies, Symlet, Coiflet and Meyer have been used for the Continuous Wavelet Transform to investigate the most suitable function for defect detection. This research also investigates the effect of surrounding soil on wavelet transforms for different mother wavelet functions.
文摘This work deals with an application in parametric modeling of problems regarding pipelines buried in static system, written in C＋＋ using ObjectARX functions. The application is fully integrated with AutoCAD through saproms.dll and saproms.arx libraries where the stages of pre-processing, processing and post-processing are done in AutoCAD sotlware environment itself without having to export data to another processing environment. The analysis processing is done by functions whose algorithms are based on the solution of the coupling between the FEM （finite element method） and the BEM （boundary element method）. The representation of the homogeneous pipeline is made by the FEM using a finite element in the form of a cylindrical panel called CYS （cylindrical shell）, developed from the homogeneous isotropic model proposed initially by Djoudi Bahai, who uses the philosophy of the assumed deformation model （assumed strain based model）. The soil is taken to be a continuum infinite or semi-infinite elastic solid patterned by BEM where special boundary elements are proposed with curved surface or curved edges to represent the soil-structure interaction mainly in the areas of contact with the pipeline.
基金National Natural Science Foundation of China (Grant No. 10574094)
文摘This paper presents a new sonochemistry reactor, which consists of a cylindrical tube with a certain length and piezoelectric transducers at tube’s end with the longitudinal vibration. The tube can effectively transform the longitudinal vibration into the radial vibration and thereby generates ultrasound. Furthermore, ultrasound can be focused to form high-intensity ultrasonic field inside tube. The reactor boasts of simple structure and its whole vessel wall can radiate ultrasound so that the electroacoustic transfer efficiency is high. The focused ultrasonic field provides good condition for sonochemical reaction. The length of the reactor can be up to 2 meters, and liquids can pass through it continuously, so it can be widely applied in liquid processing such as sonochemistry.
文摘This paper presents a combination of the hybrid spectral collocation technique and the spectral homotopy analysis method(SHAM for short) for solving the nonlinear boundary value problem(BVP for short) for the electrohydrodynamic flow of a fluid in an ion drag configuration in a circular cylindrical conduit. The accuracy of the present solution is found to be in excellent agreement with the previously published solution. The authors use an averaged residual error to find the optimal convergence-control parameters. Comparisons are made between SHAM generated results, results from literature and Matlab ode45 generated results, and good agreement is observed.
