This review considers the pathobiology of non-impact blast-induced neurotrauma (BINT). The pathobiology of traumatic brain injury (TBI) has been historically studied in experimental models mimicking features seen in the civilian population. These brain injuries are characterized by primary damage to both gray and white matter and subsequent evolution of secondary pathogenic events at the cellular, biochemical, and molecular levels, which collectively mediate widespread neurodegeneration. An emerging field of research addresses brain injuries related to the military, in particular blast-induced brain injuries. What is clear from the effort to date is that the pathobiology of military TBIs, particularly BINT, has characteristics not seen in other types of brain injury, despite similar secondary injury cascades. The pathobiology of primary BINT is extremely complex. It comprises systemic, local, and cerebral responses interacting and often occurring in parallel. Activation of the autonomous nervous system, sudden pressure-increase in vital organs such as lungs and liver, and activation of neuroendocrine-immune system are among the most important mechanisms significantly contributing to molecular changes and cascading injury mechanisms in the brain.

https://journals.sagepub.com/doi/pdf/10.1038/jcbfm.2009.203

Traumatic brain injury: an overview of pathobiology with emphasis on military populations

https://wind-energy.ucoz.com/works/Development_of_a_shrouded_wind_turbine_with_a_flan.pdf

Development of a shrouded wind turbine with a flanged diffuser

We have developed a new wind turbine system that consists of a diffuser shroud with a broad-ring brim at the exit periphery and a wind turbine inside it. The shrouded wind turbine with a brimmed diffuser has demonstrated power augmentation by a factor of about 2–5 compared with a bare wind turbine, for a given turbine diameter and wind speed. This is because a low-pressure region, due to a strong vortex formation behind the broad brim, draws more mass flow to the wind turbine inside the diffuser shroud.

/pdf/a-shrouded-wind-turbine-generating-high-output-power-with-4wnlucezds.pdf

A Shrouded Wind Turbine Generating High Output Power with Wind-lens Technology

History of the development of DAWT's stretches a period of more than 50 years. So far without any commercial success. In the initial years of development the conversion process was not understood very well. Experimentalists strived at maximising the pressure drop over the rotor disk, but lacked theoretical insight into optimising the performance. Increasing the diffuser area as well as the negative back pressure at the diffuser exit was found profitable in the experiments. Claims were made that performance augmentations with a factor of 4 or more were feasible, but these claims were not confirmed experimentally. With a simple momentum theory, developed along the lines of momentum theory for bare windturbines, it was shown that power augmentation is proportional to the mass flow increase generated at the nozzle of the DAWT. Such mass flow augmentation can be achieved through two basic principles: increase in the diffuser exit ratio and/or by decreasing the negative back pressure at the exit. The theory predicts an optimal pressure drop of 8/9 equal to the pressure drop for bare windturbines independent from the mass flow augmentation obtained. The maximum amount of energy that can be extracted per unit of volume with a DAWT is also the same as for a bare wind turbine. Performance predictions with this theory show good agreement with a CFD calculation. Comparison with a large amount of experimental data found in literature shows that in practice power augmentation factors above 3 have never been achieved. Referred to rotor power coefficients values of CP,rotor =2.5 might be achievable according to theory, but to the cost of fairly large diffuser area ratio's, typically values of β >4.5.

/pdf/the-science-of-making-more-torque-from-wind-diffuser-52pe7xaz2p.pdf

The science of making more torque from wind: Diffuser experiments and theory revisited

Two-dimensional, unsteady, compressible flow fields produced by the interactions between a single vortex or a pair of vortices and a shock wave are simulated numerically. The Navier–Stokes equations are solved by a finite difference method. The sixth-order-accurate compact Pade scheme is used for spatial derivatives, together with the fourth-order-accurate Runge–Kutta scheme for time integration. The detailed mechanics of the flow fields at an early stage of the interactions and the basic nature of the near-field sound generated by the interactions are studied. The results for both a single vortex and a pair of vortices suggest that the generation and the nature of sounds are closely related to the generation of reflected shock waves. The flow field differs significantly when the pair of vortices moves in the same direction as the shock wave than when opposite to it.

Sound generation by shock–vortex interactions

Experimental and numerical investigations of flow fields behind a small wind turbine with a flanged diffuser

This paper describes experimental and numerical studies of the focusing process of shock waves reflected from various shapes of a parabolic reflector. The effect of incident shock strength on the focusing process was also investigated. Experiments were carried out in a conventional shock tube and a test gas was air for incident shock Mach numbers ranging from 1.1 to 2.0. In the experiments, the process of shock focusing was visualized by schlieren method. Numerical simulations were conducted for incident shock Mach numbers up to 3.0 by solving the two-dimensional unsteady Euler equations. The numerical results were compared with experiment for various parabolic reflector shapes and for various incident shock Mach numbers. Based on the experimental and computational results, the pattern of shock focusing and shock focusing mechanism are discussed.

Experimental and computational studies focusing processes of shock waves reflected from parabolic reflectors

http://iopscience.iop.org/article/10.1016/S0169-5983(97)00005-1/pdf

Shock formation by compressible vortex ring impinging on a wall

The MUSES-C mission is being prepared at the Institute of Space and Astronautical Science (ISAS). The MUSES-C spacecraft is equipped with four ion engines, and usually three ion engines are operated simultaneously. This paper describes the numerical studies of a plume exhausted from the ion engines of the MUSES-C. The direct simulation Monte Carlo (DSMC) method is employed for determining the flowfield of the neutral atoms, and the particle-in-cell (PIC) method is combined with the DSMC method to deal with the motion of the ions. The simulation results for the operation of a single ion engine are compared with experiments conducted at ISAS. It is revealed that the profiles of the ion beam are sensitive to the ion beam divergence angle at the engine exit and the electron temperature of the flowfield. Based on the simulation results of a single ion engine, a three-dimensional DSMC-PIC simulation for the simultaneous operation of three ion engines is carried out, and the interaction between plumes from the ion engines and the behavior of the CEX ions are investigated.

Michio Nishida

Papers

Experimental and numerical investigations of flow fields behind a small wind turbine with a flanged diffuser

Experimental and computational studies focusing processes of shock waves reflected from parabolic reflectors

Shock formation by compressible vortex ring impinging on a wall

DSMC-PIC Analysis of a Plume from MUSES-C Ion Engines

CHAPTER 4.1 – Shock Tubes