Propulsion system mathematical model for a lift/cruise fan V/STOL aircraft

A propulsion system mathematical model is documented that allows calculation of internal engine parameters during transient operation. A non-realtime digital computer simulation of the model is presented. It is used to investigate thrust response and modulation requirements as well as the impact of duty cycle on engine life and design criteria. Comparison of simulation results with steady-state cycle deck calculations showed good agreement. The model was developed for a specific 3-fan subsonic V/STOL aircraft application, but it can be adapted for use with any similar lift/cruise V/STOL configuration

Majorana spinors and extended Lorentz symmetry in four-dimensional theory

An extended local Lorentz symmetry in four-dimensional (4D) theory is considered. A source of this symmetry is a group of general linear transformations of four-component Majorana spinors GL(4,M) which is isomorphic to GL(4,R) and is the covering of an extended Lorentz group in a 6D Minkowski space M(3,3) including superluminal and scaling transformations. Physical space-time is assumed to be a 4D pseudo-Riemannian manifold. To connect the extended Lorentz symmetry in the M(3,3) space with the physical space-time, a fiber bundle over the 4D manifold is introduced with M(3,3) as a typical fiber. The action is constructed which is invariant with respect to both general 4D coordinate and local GL(4,M) spinor transformations. The components of the metric on the 6D fiber are expressed in terms of the 4D pseudo-Riemannian metric and two extra complex fields: 4D vector and scalar ones. These extra fields describe in the general case massive particles interacting with an extra U(1) gauge field and weakly interacting with ordinary particles, i.e. possessing properties of invisible (dark) matter.Comment: 24 page

Radial Redshift Space Distortions

The radial component of the peculiar velocities of galaxies cause displacements in their positions in redshift space. We study the effect of the peculiar velocities on the linear redshift space two point correlation function. Our analysis takes into account the radial nature of the redshift space distortions and it highlights the limitations of the plane parallel approximation. We consider the problem of determining the value of \beta and the real space two point correlation function from the linear redshift space two point correlation function. The inversion method proposed here takes into account the radial nature of the redshift space distortions and can be applied to magnitude limited redshift surveys that have only partial sky coverage.Comment: 26 pages including 11 figures, to appear in Ap

The cosmological origin of the Tully-Fisher relation

We use high-resolution cosmological simulations that include the effects of gasdynamics and star formation to investigate the origin of the Tully-Fisher relation in the standard Cold Dark Matter cosmogony. Luminosities are computed for each model galaxy using their full star formation histories and the latest spectrophotometric models. We find that at z=0 the stellar mass of model galaxies is proportional to the total baryonic mass within the virial radius of their surrounding halos. Circular velocity then correlates tightly with the total luminosity of the galaxy, reflecting the equivalence between mass and circular velocity of systems identified in a cosmological context. The slope of the relation steepens slightly from the red to the blue bandpasses, and is in fairly good agreement with observations. Its scatter is small, decreasing from \~0.45 mag in the U-band to ~0.34 mag in the K-band. The particular cosmological model we explore here seems unable to account for the zero-point of the correlation. Model galaxies are too faint at z=0 (by about two magnitudes) if the circular velocity at the edge of the luminous galaxy is used as an estimator of the rotation speed. The Tully-Fisher relation is brighter in the past, by about ~0.7 magnitudes in the B-band at z=1, at odds with recent observations of z~1 galaxies. We conclude that the slope and tightness of the Tully-Fisher relation can be naturally explained in hierarchical models but that its normalization and evolution depend strongly on the star formation algorithm chosen and on the cosmological parameters that determine the universal baryon fraction and the time of assembly of galaxies of different mass.Comment: 5 pages, 4 figures included, submitted to ApJ (Letters

Progress Report of the Kansas Basement Rocks Committee and Additional Precambrian Wells

The Kansas Basement Rocks Committee is actively collecting data pertaining to Precambrian rocks of Kansas. An additional 84 wells known to encounter the Precambrian bring the total number of known Precambrian tests in Kansas to about 2,200 as of December 31, 1961. A generalized configuration map of the surface of Precambrian rocks shows major post-Mississippian structural features in the state. Potassium-argon age dates for five samples range from 1165 to 1460 million years

Progress Report of the Kansas Basement Rocks Committee and Additional Precambrian Wells

The Kansas Basement Rocks Committee is actively collecting data pertaining to Precambrian rocks of Kansas. An additional 84 wells known to encounter the Precambrian bring the total number of known Precambrian tests in Kansas to about 2,200 as of December 31, 1961. A generalized configuration map of the surface of Precambrian rocks shows major post-Mississippian structural features in the state. Potassium-argon age dates for five samples range from 1165 to 1460 million years

Nonlinear interplay of Alfven instabilities and energetic particles in tokamaks

The confinement of energetic particles (EP) is crucial for an efficient heating of tokamak plasmas. Plasma instabilities such as Alfven Eigenmodes (AE) can redistribute the EP population making the plasma heating less effective, and leading to additional loads on the walls. The nonlinear dynamics of toroidicity induced AE (TAE) is investigated by means of the global gyrokinetic particle-in-cell code ORB5, within the NEMORB project. The nonperturbative nonlinear interplay of TAEs and EP due to the wave-particle nonlinearity is studied. In particular, we focus on the nonlinear modification of the frequency, growth rate and radial structure of the TAE, depending on the evolution of the EP distribution in phase space. For the ITPA benchmark case, we find that the frequency increases when the growth rate decreases, and the mode shrinks radially. This nonlinear evolution is found to be correctly reproduced by means of a quasilinear model, namely a model where the linear effects of the nonlinearly modified EP distribution function are retained.Comment: Submitted to Plasma Phys. Control. Fusio

Bloch-Redfield equations for modeling light-harvesting complexes

We challenge the misconception that Bloch-Redfield equations are a less powerful tool than phenomenological Lindblad equations for modeling exciton transport in photosynthetic complexes. This view predominantly originates from an indiscriminate use of the secular approximation. We provide a detailed description of how to model both coherent oscillations and several types of noise, giving explicit examples. All issues with non-positivity are overcome by a consistent straightforward physical noise model. Herein also lies the strength of the Bloch-Redfield approach because it facilitates the analysis of noise-effects by linking them back to physical parameters of the noise environment. This includes temporal and spatial correlations and the strength and type of interaction between the noise and the system of interest. Finally we analyze a prototypical dimer system as well as a 7-site Fenna-Matthews-Olson (FMO) complex in regards to spatial correlation length of the noise, noise strength, temperature and their connection to the transfer time and transfer

Dark Halo and Disk Galaxy Scaling Laws in Hierarchical Universes

We use cosmological N-body/gasdynamical simulations that include star formation and feedback to examine the proposal that scaling laws between the total luminosity, rotation speed, and angular momentum of disk galaxies reflect analogous correlations between the structural parameters of their surrounding dark matter halos. The numerical experiments follow the formation of galaxy-sized halos in two Cold Dark Matter dominated universes: the standard Omega=1 CDM scenario and the currently popular LCDM model. We find that the slope and scatter of the I-band Tully-Fisher relation are well reproduced in the simulations, although not, as proposed in recent work, as a result of the cosmological equivalence between halo mass and circular velocity: large systematic variations in the fraction of baryons that collapse to form galaxies and in the ratio between halo and disk circular velocities are observed in our numerical experiments. The Tully-Fisher slope and scatter are recovered in this model as a direct result of the dynamical response of the halo to the assembly of the luminous component of the galaxy. We conclude that models that neglect the self-gravity of the disk and its influence on the detailed structure of the halo cannot be used to derive meaningful estimates of the scatter or slope of the Tully-Fisher relation. Our models fail, however, to match the zero-point of the Tully-Fisher relation, as well as that of the relation linking disk rotation speed and angular momentum. These failures can be traced, respectively, to the excessive central concentration of dark halos formed in the Cold Dark Matter cosmogonies we explore and to the formation of galaxy disks as the final outcome of a sequence of merger events. (abridged)Comment: submitted to The Astrophysical Journa

Global Alfven Eigenmodes in the H-1 heliac

Recent upgrades in H-1 power supplies have enabled the operation of the H-1 experiment at higher heating powers than previously attainable. A heating power scan in mixed hydrogen/helium plasmas reveals a change in mode activity with increasing heating power. At low power (<50 kW) modes with beta-induced Alfven eigenmode (BAE) frequency scaling are observed. At higher power modes consistent with an analysis of nonconventional Global Alfven Eigenmodes (GAEs) are observed, the subject of this work. We have computed the mode continuum, and identified GAE structures using the ideal MHD solver CKA and the gyrokinetic code EUTERPE. An analytic model for ICRH-heated minority ions is used to estimate the fast ion temperature from the hydrogen species. Linear growth rate scans using a local flux surface stability calculation, LGRO, are performed. These studies demonstrate growth from circulating particles whose speed is significantly less than the Alfven speed, and are resonant with the mode through harmonics of the Fourier decomposition of the strongly-shaped heliac magnetic field. They reveal drive is possible with a small, hot energetic tail of the hydrogen species. Local linear growth rate scans are also complemented with global calculations from CKA and EUTERPE. These qualitatively confirm the findings from the LGRO study, and show that the inclusion of finite Larmor radius effects can reduce the growth rate by a factor of three, but do not affect marginal stability. Finally, a study of damping of the global mode with the thermal plasma is conducted, computing continuum, and the damping arising from parallel electric fields. We find that continuum damping is of order 0.1% for the configuration studied. The inclusion of resistivity lifts the damping to 19%. Such large damping is consistent with experimental observations that in absence of drive the mode decays rapidly (~0.1 ms).Comment: 18 pages, 15 figures, submitted 07/04/2017 to Plasma Physics and Controlled Fusio