Coolant passage fin heat transfer and pressure drop performance

Coolant passage fin heat transfer and pressure drop in hypersonic research engine test

A Three-Dimensional Tight-Binding Model and Magnetic Instability of KFe2e2

For a newly discovered iron-based high T_c superconducting parent material KFe2Se2, we present an effective three-dimensional five-orbital tight-binding model by fitting the band structures. The three t2g-symmetry orbitals of the five Fe 3d orbitals mainly contribute to the electron-like Fermi surface, in agreement with recent angle-resolved photoemission spectroscopy experiments. To understand the groundstate magnetic structure, the two- and three-dimensional dynamical spin susceptibilities within the random phase approximation are investigated. It obviously shows a sharp peak at wave vector $\mathbf{Q}$ $\thicksim$ ($\pi$, $\pi$), indicating the magnetic instability of {\it N$\acute{e}$el}-type antiferromagnetic rather than ($\pi$/2, $\pi$/2)-type antiferromagnetic ordering. While along \emph{c} axis, it exhibits a ferromagnetic coupling between the nearest neighboring FeSe layers. The difference between the present results and the experimental observation in KxFe2-ySe2 is attributed to the presence of Fe vacancy in the latter.Comment: 14 pages, 8 figure

Did the Late Paleozoic Ice Age cause reduced evolutionary rates in marine invertebrates? : A test using the crinoid fossil record

A 2003 paper by Stanley and Powell reported depressed rates of origination and extinction in marine invertebrates during the Late Paleozoic Ice Age (LPIA) as compared to background rates during the Paleozoic. In their paper, trilobites were used as a specific example to support the hypothesis of sluggish evolutionary rates. Thus, can their hypothesis be tested using a different fossil group? Using an updated version of the crinoid database from Sepkoski\u27s 2002 compendium of fossil marine genera, adding data from multiple sources, rates of origination, extinction, and genus duration were calculated at the stage level for the interval from the Early Devonian (419 Ma) to the Late Permian (254 Ma). This 165 m.y. time span includes non-glacial intervals before and after the LPIA, which spanned the Serpukhovian (331 Ma) to Sakmarian (290 Ma), providing background rates for comparison. The data generated on crinoid evolutionary rates during the Middle to Late Paleozoic were analyzed and compared to Stanley and Powell\u27s data to determine if crinoid evolutionary patterns support their findings or suggest an alternative hypothesis.;The results of the analysis performed on the updated crinoid database support Stanley and Powell\u27s hypothesis of depressed evolutionary rates in marine invertebrates during the LPIA. Rates of origination and extinction in all crinoid clades were reduced during the LPIA compared to the intervals examined before and after the LPIA. However, crinoid diversity was higher during the LPIA than the surrounding time intervals as origination rates exceeded extinction rates. This increased diversity does not follow Stanley and Powell\u27s findings of reduced diversity in marine invertebrates during the LPIA. The increased diversity of crinoids through the LPIA indicates that taphonomic bias is not responsible for the depressed evolutionary rates. A lower diversity count would be expected during a glacial interval due to lower sea levels, which would result in reduced outcrop volume.;The difference in diversity trends between crinoids and other marine invertebrates is due to factors specific to the advanced cladids crinoid clade. Unstable, fluctuating environmental conditions during the LPIA created habitats suitable for opportunistic crinoid genera, which reduced both the probability of origination and extinction. Advanced cladids were solely responsible for the high diversity of crinoids during the LPIA because they represented the majority of crinoids. The increased diversity of the advanced cladids is due to their unique adaptation of muscular articulation, which allowed them to thrive in marine settings with increased siliciclastic influx. The advanced cladids responded opportunistically to the environmental change brought on by the Alleghenian orogeny, which caused an increase in siliciclastic dominated marine environments. Despite the advanced cladids\u27 departure from the expected diversity count, the results of analyses performed on the updated crinoid database support Stanley and Powell\u27s original hypothesis of depressed evolutionary rates in marine invertebrates during the LPIA

The 2006 Reform of the EU Domestic Policy Regime for Bananas. An Assessment of its Impact on Trade.

The paper provides a quantitative assessment of the possible market implications of the December 2006 reform of the EU domestic policy regime for bananas. It is shown that, depending on implementation choices to be made at the member country level, the impact of the domestic policy reform on trade can be of a larger order of magnitude than that of the controversial tariff-only regime the EU introduced earlier in the same year. The simulations presented in this paper show that, ceteris paribus, if France, Portugal and Spain decide to decouple payments to their banana producers EU imports will increase by 13% and MFN exports to the EU by 16%; if they decide for a 2005 Memorandum-like option, EU imports still increase by 9% and MFN exports to the EU by 11%.International Relations/Trade,

Research Of Sensomotor Reaction, Memory And Attention Indicies Under Sensory Deprivation

The article considers the influence of sensory (visual and auditory) deprivation on a sensorimotor response, memory, and attention among 8-11 years old children. The literature review concludes that sensory deprivation causes discomfort and problems in perceiving of reality. Also, under the influence of various factors that damage body structures, compensatory reactions are launched to compensate for impaired functions. The processes that provide the body with the restoration of lost structures and impaired functions of the pathology are called «compensatory-adaptive processes». Having conducted statistical analysis of the obtained data of latent periods of different sensomotor responses among children with sensory deprivation and the control group, it is seen, that the level of stimuli in the form of figures was higher among children with hearing impairments, and in the form of sounds – in the group of children with visual impairments. According to the results of our study, we can assume that in groups of children with sensory deprivation the process of compensating the impaired function of a particular analyzer takes place at the expense of another one

Charmed-strange Mesons Experimental Results

Two new states in the charm strange sector, DsJ(2317) and DsJ(2460), have recently been discovered at electron positron collider experiments. The new states are first observed in the dominant Ds pi0 and Ds* pi0 modes respectively and are very narrow. They are consistent with 0+ and 1+ P-wave charm anti-strange mesons. The DsJ(2460) meson is also observed in Ds gamma and Ds pi+ pi- modes. A review of the discoveries and possible explanations is given.Comment: 5 pages, 5 figures and 1 table. To appear in the AIP proceedings of Beauty 2003, Carnegie Mellon University, Pittsburgh, Oct14-18, 200