1,739 research outputs found
Simulation of transient energy distributions in sub-ns streamer formation
Breakdown and streamer formation is simulated in atmospheric pressure nitrogen for a 2D planar electrode system. A PIC code with multigrid potential solver is used to simulate the evolution of the non-equilibrium ionization front on sub-nanosecond timescales. The ion and electron energy distributions are computed, accounting for the inclusion of inelastic scattering of electrons, and collisionally excited metastable production and ionization. Of particular interest is the increased production of metastable and low-energy ions and electrons when the applied field is reversed during the progress of the ionization front, giving insight into the improved species yields in nanosecond pulsed systems
Wind-Tunnel Tests of a 1/6-Scale Model of Republic XF-12 Vertical Tail Incorporating a De-Icing Air Duct
A 1/6-scale model of the Republic XF-12 vertical tail with stub fuselage, stub horizontal tail, and a de-icing air duct was tested in the Langley stability tunnel. The investigation consisted of a study of the effects of the duct, with and without air flow, on the aerodynamic characteristics of the model. The model tested was a revision of a model previously tested in the Langley stability tunnel. The revised model differed from the original model in that it incorporated a de-icing air duct, included a dorsal fin, and had a larger stub fuselage. A comparison of data obtained form tests of the original and revised models was made. The results of the investigation indicated that the air duct had very little effect on the aerodynamic characteristics of the model. A small change occurred in the variation of rudder hinge-moment coefficient with angle of attack but it is believed that this change can be corrected by a properly applied spring tab
Grey and white matter differences in Chronic Fatigue Syndrome : A voxel-based morphometry study
Conflicts of interest and source of funding The authors declare no conflicts of interest. This research was funded by the Medical Research Council (MR/J002712/1). AF is supported by Research Capability Funding from the Newcastle upon Tyne Hospitals NHS Foundation Trust and the Northumberland, Tyne and Wear NHS Foundation Trust.Peer reviewedPublisher PD
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Modelling the moistening of the free troposphere during the northwestward progression of Indian monsoon onset
Understanding and prediction of the Indian monsoon onset is of paramount importance for agricultural planning that affects food production and the gross domestic product of the country. A recent observational study suggests that the progression of the Indian monsoon onset in a northwestward direction, which is perpendicular to the mean flow, is reinforced by the moistening of the free troposphere by pre-monsoon showers and wetting of the land surface. As the onset progresses, the mid-tropospheric dry layer is thought to be constantly moistened from below by detrainment from shallow cumulus and congestus clouds from the southeast. The dry layer becomes much shallower towards southeast India, making the profile closer to moist adiabatic, providing favourable conditions for deep cumulus convection. Increased moistening of the free troposphere thereby pushes the northern limit of moist convection to move northwestwards. Here we examine the representation of this process in hindcast simulations from the fully coupled atmosphere-ocean seasonal forecast system of the UK Met Office, GloSea5. The model effectively captures the mid-level dry air intrusion from the northwest which suppresses convection over the northwestern parts of India. We also show that detrainment from shallow convection, measured by moisture tendencies around the freezing level, acts to saturate the free troposphere ahead of the monsoon onset, eroding the dry-layer from the southeast. This work suggests that initialized coupled models are capable of simulating dynamic and thermodynamic processes inherent in monsoon progression during the onset
Corrections to Gravity due to a Sol Manifold Extra Dimensional Space
The corrections to the gravitational potential due to a Sol extra dimensional
compact manifold, denoted as , are studied. The total spacetime is of
the form . The range of the Sol corrections is investigated
and compared to the range of the corrections.Comment: 13 pages, 10 figures, published versio
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