Search

• This paper describes an application of ultrasound techniques to solid–liquid fluidized beds. • The ultrasonic methods are used for obtaining velocity profiles, particle size distribution, and solids volume fraction. • The solid velocity profiles and particle size distributions were measured for four different sizes of glass particles ranging from 500 μm to 1250 μm at a solid volume fraction of 35%. • The importance of the techniques as a diagnostic tool to investigate the particles segregation behaviour in solid–liquid fluidized beds at different fluidization conditions are reported. This paper describes an application of ultrasound techniques to solid–liquid fluidized beds. The ultrasonic methods, experimental setups, and the signal processing for obtaining velocity profiles, particle size distribution, and solids volume fraction are discussed. The techniques are based on the measurement of the ultrasound attenuation coefficient, sound speed, and frequency shift of the propagated sound wave. The ultrasound propagation speed in solid–liquid fluidized bed was measured to be between 1504 m/s and 1565 m/s for glass particles with volume fractions spanning from 27% to 70% in water. The solid velocity profiles were measured for liquid superficial velocities varying from 0.84 cm/s to 4.24 cm/s. The particle size distributions were measured for four different sizes of glass particles ranging from 500 μm to 1250 μm at a solid volume fraction of 35%. This paper also reports the importance of the techniques as a diagnostic tool to investigate the particles segregation behaviour in solid–liquid fluidized beds at different fluidization conditions. The results indicated that ultrasound techniques are a powerful tool that can characterise in real-time highly concentrated solid–liquid systems. [ABSTRACT FROM AUTHOR]

This paper presents development and implementation of a novel digital signal processing algorithm for on-line estimation of peak value of the fundamental component of a non-sinusoidal power system signal. The algorithm relies on stable band-pass first and second degree digital integrator based rigorous mathematical deduction and recombines itself with zero-crossing avoiding technique. Compared with the well-established technique such as the enhanced phase-locked-loop (EPLL) based system, the proposed algorithm provides higher degree of immunity and insensitivity to harmonics and noise, and faster response. Based on simulation studies, performances of the proposed algorithm at different operating conditions have been presented and its accuracy and response time have been compared with the EPLL systems. Moreover, a simple laboratory setup implemented by MATLAB and dedicated hardware is built to verify the performance of the proposed algorithm in real time applications. The framework of laboratory prototype has been given out and the necessary modification in proposed algorithm for on-line implementation has been discussed. [ABSTRACT FROM AUTHOR]

Crude oil, with relatively high viscosity, freezing-point and content of wax, is usually transported by heated oil pipelines (HOP) containing many pumping and heating stations. There are many different selections of operation parameters or values of pumps and heating furnaces, but all these different “selections” can satisfy output task and safety requirements. The power and fuel cost of pumping and heating account for 1–3% of the total energy consumption. For the energy saving purpose, it is necessary to optimize the HOP operations. In this paper a dynamic model of HOP was proposed and used to calculate the soil temperature field outside HOP, and then both the spatial and temporal distributions of pressure and temperature of field inside HOP. Using this calculation method and its results, an optimization model is established aiming at minimizing energy cost of running HOP, with outlet temperatures of each heating station, on–off states of each pump, and their head matrix of delivery as the optimization variables. Then a mixed algorithm combining differential evolution algorithm with particle swarm optimization algorithm is used to solve this model. The optimization results are applied to Rizhao–Yizheng digital long distance HOP (375 km). Research shows that: verified by real time data acquired by the SCADA, the relative error of the dynamic model’s result is 4.042%, much less than that of the steady-state model’s result (22.67%). The optimized operation scheme can save 17.59% of energy cost for oil transportation task of 2640 m 3 /h. Energy saving effect is remarkable. [ABSTRACT FROM AUTHOR]

Abstract: Since the empirical mode decomposition (EMD) lacks strict orthogonality, a new method for multicomponent signal decomposition, orthogonal empirical mode decomposition (OEMD), is proposed by this paper. The essential principle of this method is to obtain the intrinsic mode functions (IMFs) and the residue by self-adaptive band-pass filtering. Firstly, the feasibility of OEMD is theoretically analyzed, then its strict orthogonality and completeness is proved, and the orthogonal basis used in OEMD is generated. Secondly, the method of analytical band-pass filtering which preserves perfect band-pass feature in the frequency domain is presented, then two fast algorithms to implement OEMD are proposed, i.e. IMF sequential searching (ISS) algorithm and IMF binary searching (IBS) algorithm. The speed of IBS is faster than that of ISS, whereas IBS algorithm may obtain much more false IMFs than ISS when signals are of complex spectral constitutions. Finally, OEMD is applied to both synthetic signals and mechanical vibration signals, the results show that compared with EMD, OEMD better solves mode aliasing, avoids the occurrence of false mode, is free of end extension, and can be effectively applied to mechanical fault diagnosis. [Copyright &y& Elsevier]

[Display omitted] • Non-contact measurement method is proposed for hexagonal shaft bending deflection. • The valid data is extracted within the allowable incident angle of laser sensor. • The measurement accuracy can reach the same level as ZEISS Calypso scanner. • High precision, high efficiency, non-rotation speed limited are method advantages. The hexagonal shaft is often used as the important transmission component. Its bending deflection is a main factor affecting the working capability and fatigue life. In this paper, a contactless continuous measurement method based on contour reconstruction is proposed, which only uses a laser displacement sensor moving at a constant speed to collect the profile information. According to the allowable incident angle, the valid data with high precision is extracted. An algorithm seeking for section center is deduced according to the hexagon edge equations fitted by the least square method, then, the three-dimensions blending axis is obtained. The method precision is analyzed by theoretical error analysis. Finally, the feasibility and high accuracy of the novel method are demonstrated by comparing with ZEISS Calypso scanner results and the repeatability and reproducibility (R&R) analysis. [ABSTRACT FROM AUTHOR]

In this paper, we develop an algorithm (hereby referred to as the S-function generator: SFG) for the automatic generation of dynamic S-function blocks which can be used for geometrical error compensation of precision machines. The function block is composed of neural network approximations of the geometrical errors of the machines which will serve as the basis for error compensation. It is generated automatically based on only raw calibration data obtained from a laser interferometer and simple user specifications in terms of approximation accuracy requirements. No coding is necessary on the part of the user. This tremendously simplifies the use of the functional error compensation approach which has clear advantages over a traditional look-up table approach. The SFG has been applied to the compensation of two XY tables and the evaluation tests show that the overall geometrical errors can be significantly reduced. [Copyright &y& Elsevier]

• Introduction of an algorithm to identify water ponding zones upon road surfaces. • The algorithm can produce analysis at global and local scales of a route. • The global scale analysis of a route can consider several road sections. • And produces results like the area covered and/or volume of water on the road. • The local scale analysis produces results like water distribution on the road. In this paper, an algorithm to identify the water that will be incident upon road surfaces during rainfall events is introduced to predict the likely areas of water ponding. This program can produce a global and local analysis of a route. The analysis on a global scale can consider several road sections and produces basic results such as the water-covered surface percentage. This is effectively a network-level tool. The analysis at a local scale in which only one section is considered, the program can produce results like water distribution. Even if the algorithm, in its current state, does not take into account such factors as gradient, drainage, locations of gullies, road type, and local features such as intersections with other roads, it represents a very promising first step for future developments of a more complete tool. [ABSTRACT FROM AUTHOR]