Multi-scale characteristics of vibration acceleration signals in vapor-liquid- solid fluidized bed evaporator

In this work, the multi-value phenomenon of correlation dimension and its relationship with multi-scale flow behavior were investigated by using chaos analysis of time series of vibration acceleration as well as pressure drop obtained from vapor-liquid-solid fluidized bed evaporator. Modified methods of Grassberger & Procaccia were applied in the chaos analysis. Results indicate that multi- (generally three) value of correlation dimension in the pressure drop original signals results from the multi-scale behavior in the systems of vapor-liquid and vapor-liquid-solid flow boiling. However, only one value of correlation dimension can be found in the vibration acceleration original signals. The reason is that the energy of the high frequency vibration signal is very strong, and it can cover up the multi-scale phenomena. When the vibration acceleration signals were analyzed using the Daubechies 8 wavelet, the dual effects of solid particles on the local hydrodynamics can be obtained

Charging and Discharging Mechanism of Polyimide under Electron Irradiation and High Voltage

Polyimide has been widely used as insulating and structural materials in spacecraft due to its excellent electrical, thermal and mechanical properties. However, its charging and discharging problem in harsh space environment has been a major limit to the development of high-voltage and high-power spacecraft. In this chapter, charging and discharging phenomena of dielectric materials under electron irradiation environment were presented. First, the electrical properties of polyimide consisting of dielectric properties, trap properties, conductivity and electrical breakdown properties were investigated, which have great influences on charging and discharging characteristics. Then, a surface charging model under relatively low-energy electron irradiation was proposed for polyimide, based on the synergistic effects of electron movement above surface and charge transport in surface layer. The DC surface flashover of polyimide under electron irradiation with different energies, fluxes and incident angles was investigated. Furthermore, a deep charging model under high-energy electron irradiation with the Fluence Model for Internal Charging (FLUMIC) spectrum was established. The effects of electron flux enhancement and operating voltage on charging characteristics were discussed in different grounding modes. It indicates that the processes of discharging under electron irradiation have a close link with the charge transport characteristics of polyimide

Heat transfer characteristics of the vapor-liquid-solid boiling flow in a fluidized bed evaporator

The heat transfer enhancement mechanism of the vapor-liquid-solid three-phase boiling flow in a fluidized bed evaporator was explained in a new way. The subject was investigated with comprehensive standard deviation, power spectral density, wavelet decomposition analyses of differential pressure, vibration acceleration, volume flow and temperature signals. Main results are as follows. The generation of big vapor bubbles and the length of vaporization section can be reflected in the downward spikes and standard deviation of differential pressure signals, which responds to boiling heat transfer process. The main influence of solid particles on tube wall is axial shear force and the volume flow of the mixing flow is balanced by the driving force and flow resistance, which relate to the convective heat transfer process. As the steam pressure grows, the heat transfer process is enhanced due to the increased vaporization section length and volume flow of mixing flow. The improvement of heat transfer process with solid holdup is mainly attributed to the collision of solid particles to tube walls

Scanning-fluorescence Reader Based on Embedded System

To measure the concentration of C-reactive protein (CRP) in serum, a portable, scanning-fluorescence reader based on time-resolved fluoroimmunoassays was developed. The scanning-fluorescence reader integrates with the AD7707 converter, which performs at a high accuracy. The photosensitive diode acts as the photoelectric conversion device, an optical module based on optical fibers, which is able to concentrate the excitation light from an LED into a line-shape beam, was designed to sendand receive the optical signal. The device subsequently addresses waveform data using a gradient, smoothing, and binarization method. When the device measures the CRP fluorescence test strip, the results exhibited a good linearity (0.99998) and the CVs (coefficient of variation) were below 5%, which indicate high accuracy. At the same time the system is low cost and small size

FOREARC MANTLE METASOMATISM BY 11B-DEPLETED FLUIDS FROM A HIGHLY DEHYDRATED SLAB: A SNAPSHOT OF SLAB ROLL-BACK?

Accretionary orogens form along convergent plate margins due to the ongoing subduction of oceanic lithosphere, and comprise accretionary prisms, magmatic arcs, back-arc domains, ophiolitic mélanges and possibly oceanic plateaus and continental fragments [Condie, 2007; Cawood et al., 2009]. Based on the dips and velocities of subducting slabs, accretionary orogens can be divided into retreating and advancing type, as exemplified by modern SW Pacific and Andes, respectively [Royden, 1993; Cawood et al., 2009].Accretionary orogens form along convergent plate margins due to the ongoing subduction of oceanic lithosphere, and comprise accretionary prisms, magmatic arcs, back-arc domains, ophiolitic mélanges and possibly oceanic plateaus and continental fragments [Condie, 2007; Cawood et al., 2009]. Based on the dips and velocities of subducting slabs, accretionary orogens can be divided into retreating and advancing type, as exemplified by modern SW Pacific and Andes, respectively [Royden, 1993; Cawood et al., 2009]