Equation of Energy Injection to a Dielectric Barrier Discharge Reactor

The electric energy injection from a pulsed power supply to a planar type of dielectric barrier discharge（DBD） reactor at atmospheric pressure was studied. Relations of the energy injection with barrier materials, barrier thickness, peak voltage, gap distance, electrode area,and operation temperature were experimentally investigated. The energy injection is a function of relative permittivity, barrier thickness, peak voltage, gap distance, and electrode area. The influence of operation temperature on energy injection is slight in the range of 27-300℃ but becomes obvious in the range of 300-500℃. A model was established using which the energy injection can be easily predicted.

Experiment and simulation of foaming injection molding of polypropylene/nano-calcium carbonate composites by supercritical carbon dioxide

Microcellular injection molding of neat isotactic polypropylene(iPP) and isotactic polypropylene/nano-calcium carbonate composites(i PP/nano-CaCO_3) was performed using supercritical carbon dioxide as the physical blowing agent. The influences of filler content and operating conditions on microstructure morphology of i PP and i PP/nano-CaCO_3 microcellular samples were studied systematically. The results showed the bubble size of the microcellular samples could be effectively decreased while the cell density increased for i PP/nano-CaCO_3 composites, especially at high CO_2 concentration and back pressure, low mold temperature and injection speed, and high filler content. Then Moldex 3D was applied to simulate the microcellular injection molding process, with the application of the measured ScCO_2 solubility and diffusion data for i PP and i PP/nano-Ca CO_3 composites respectively. For neat i PP, the simulated bubble size and density distribution in the center section of tensile bars showed a good agreement with the experimental values. However, for i PP/nano-CaCO_3 composites, the correction factor for nucleation activation energy F and the pre-exponential factor of nucleation rate f_0 were obtained by nonlinear regression on the experimental bubble size and density distribution. The parameters F and f_0 can be used to predict the microcellular injection molding process for i PP/nano-CaCO_3 composites by Moldex 3D.

＂One-for-several＂ rotor VVVF Technique apply to water injection station

In the process of oilfield water injection volume of injection allocation often appear with the pump displacement situation does not match, the widespread adoption of stator frequency technology allows the pump displacement and volume of injection allocation phase matching. But the technology in pump class load application speed range is limited, there is still a reflux valve control blind area,＂ turn off undead＂ problem. ＂ One-for-several＂ rotor frequency Technique in water injection station application, solved the control blind area problem, the full realization of the variable frequency close return voltage injection, at the same time, the successful implementation of the slip power efficient feedback. Stable water injection pressure of the system, and the electric energy is saved, satisfy the oilfield high efficiency, fine water needs, has a high application value.

Induced earthquakes in the development of unconventional energy resources

It has long been known that human activities such as waste fluid disposal and reservoir impoundment may cause earthquakes. Recently, anthropogenic activities to tackle the increasing energy demand and to address climate change issues are also reported to induce earthquakes. These activities have a common attribute in that fluids are injected and extracted underground and induce spatiotemporal changes of pore pressure and stress, which may cause slip on faults. Induced earthquakes not only pose significant impacts on seismic hazard assessment and preparation, but also raise the question to the society as how to balance the economic needs of resources development and the public's concerns about potential environmental impacts. Here we review the observations of fluid-injection/extraction induced earthquakes, ground deformation associated with these activities, and their physical mechanisms. Furthermore, we discuss the influences of induced earthquakes on seismic hazard models, regulatory policies on these anthropogenic activities, and current development of academic, industrial and government initiatives and collaborations in order to understand this intriguing phenomenon and address associated challenges.

Comparison between the ring current energy injection and decay under southward and northward IMF Bz conditions during geomagnetic storms

The geomagnetic storm is one of the most important geomagnetic disturbance phenomena in the geospace.Many studies assume that input of solar wind energy into the Earth's ring current only occurs when IMF Bz in GSM coordinates is southward;the ring current energy injection and decay under northward IMF Bz are not well understood and still need further investigation.In this paper,by using the large amount of data from the year 1964 to 2010,we use the empirical phase space analysis method to study the ring current energy injection and decay under northward IMF Bz and compare the results with those under southward IMF Bz condition.We have found that the largest injection Q under northward IMF Bz condition is only 7% of the largest injection under southward IMF Bz,implying that there is a very limit energy injected into the ring current region when IMF Bz is northward.The decay time decreases as VBz increases and shows a good linear trend for southward IMF Bz;while for the northward IMF Bz,there is not a clear relation between τ varies and VBz.Having taken τ as a function of injection Q instead of VBz,we have obtained the empirical relation of τ with Q for northward and southward IMF Bz conditions:the two categories are further combined together and the empirical relation τ= e(2.6 0.039 Q) is derived.Further,the pressure-corrected Dst formula Dst=Dst b P+c is derived for both southward and northward IMF Bz conditions,where the coefficients b and c are 6.9/10.4 and 10.0/15.2 when IMF Bz is southward and northward respectively.The statistical results on between the different geomagnetic indices(Dst,Kp,AE) and IMF Bz are also obtained.

A 2D DEM-LBM study on soil behaviour due to locally injected fluid

Leakage from underground pipes could result in foundations being undermined and cause damage to adjacent infrastructure. Soil particles surrounding the leaking area could be mobilised, displaced, and even washed out of the soil matrix by the leaking fluid, generating a void or cavity. A two-dimensional simulation using a coupled discrete element method and lattice Boltzmann method （DEM-LBM） has been used to investigate the behaviour of a soil bed subject to a locally injected fluid, which represents a leak in a pipe. Various values of inter-particle surface energy were also adopted to model the mechanical effects of cohesive particles. The results suggest that the inter-particle surface energy greatly influences the bed response with respect to the leaking fluid, including the excess pressure initiating the cavity, the cavity shape and its evolution rate.