NASA/GE quiet engine C acoustic test results

The acoustic investigation and evaluation of the C propulsion turbofan engine are discussed. The engine was built as a part of the Quiet Engine Program. The objectives of the program are as follows: (1) to determine the noise levels produced turbofan bypass engines, (2) to demonstrate the technology and innovations which will reduce the production and radiation of noise in turbofan engines, and (3) to acquire experimental acoustic and aerodynamic data for high bypass turbofan engines to provide a better understanding of noise production mechanisms. The goals of the program called for a turbofan engine 15 to 20 PNdB quieter than currently available engines in the same thrust class

Acoustic testing of a 1.5 pressure ratio, low tip speed fan (QEP fan B scale model)

A scale model (0.484 scale factor) of a single stage fan designed for a 1.5 pressure ratio and 1160 ft/sec tip speed was tested to determine its noise characteristics. The fan had 26 blades and 60 outlet guide vanes, with vanes spaced two rotor blade aerodynamic chords from the blades. The effects of speed, exhaust nozzle area and fan frame acoustic treatment on the scale model's noise characteristics were investigated

Clustering of Photometric Luminous Red Galaxies II: Cosmological Implications from the Baryon Acoustic Scale

A new determination of the sound horizon scale in angular coordinates is presented. It makes use of ~ 0.6 x 10^6 Luminous Red Galaxies, selected from the Sloan Digital Sky Survey imaging data, with photometric redshifts. The analysis covers a redshift interval that goes from z=0.5 to z=0.6. We find evidence of the Baryon Acoustic Oscillations (BAO) signal at the ~ 2.3 sigma confidence level, with a value of theta_{BAO} (z=0.55) = (3.90 \pm 0.38) degrees, including systematic errors. To our understanding, this is the first direct measurement of the angular BAO scale in the galaxy distribution, and it is in agreement with previous BAO measurements. We also show how radial determinations of the BAO scale can break the degeneracy in the measurement of cosmological parameters when they are combined with BAO angular measurements. The result is also in good agreement with the WMAP7 best-fit cosmology. We obtain a value of w_0 = -1.03 \pm 0.16 for the equation of state parameter of the dark energy, Omega_M = 0.26 \pm 0.04 for the matter density, when the other parameters are fixed. We have also tested the sensitivity of current BAO measurements to a time varying dark energy equation of state, finding w_a = 0.06 \pm 0.22 if we fix all the other parameters to the WMAP7 best-fit cosmology.Comment: 7 pages, 7 figures, Accepted for publication to MNRA

Acoustic testing of a 1.5 pressure ratio low tip speed fan with a serrated rotor (QEP fan B scale model)

A scale model of the bypass flow region of a 1.5 pressure ratio, single stage, low tip speed fan was tested with a serrated rotor leading edge to determine its effects on noise generation. The serrated rotor was produced by cutting teeth into the leading edge of the nominal rotor blades. The effects of speed and exhaust nozzle area on the scale models noise characteristics were investigated with both the nominal rotor and serrated rotor. Acoustic results indicate the serrations reduced front quadrant PNL's at takeoff power. In particular, the 200 foot (61.0 m) sideline noise was reduced from 3 to 4 PNdb at 40 deg for nominal and large nozzle operation. However, the rear quadrant maximum sideline PNL's were increased 1.5 to 3 PNdb at approach thust and up to 2 PNdb at takeoff thust with these serrated rotor blades. The configuration with the serrated rotor produced the lowest maximum 200 foot (61.0 m) sideline PNL for any given thust when the large nozzle (116% of design area) was employed

ФОРМИРОВАНИЕ ПРИСПОСОБИТЕЛЬНЫХ РЕАКЦИЙ УЧАЩИХСЯ В ЗАВИСИМОСТИ ОТ ТИПА ПСИХОВЕГЕТАТИВНОЙ РЕГУЛЯЦИИ

The purpose of the students (12 to 15 years old) examination was to identify the integrative criteria of assessing the nature of the functional relationships between the parameters of the psychosocial and physiological adaptation of students, depending on age, individual-typological peculiarities of vegetative regulation, personal potential at different stages of school education.The study of the characteristics of vegetative regulation of the cardiovascular system was made with a help of an automatic cardiac-rhythm programs. The research of psychophysiological parameters was fulfiled using an automatic complex. The measurement of the speed of simple visual-motor reaction (PSMR), reaction to a moving object (WFD), the level of functional mobility of nervous processes (WFP) and health brain (DDM) were made before. Features psychosocial adaptation was analyzed using 8-color Luscher test.All examinee were divided into three groups on the basis of the statistical characteristics of the cardiac rhythm by the tone source autonomic tone: “vagotonia” (with a predominance of parasympathetic sistems), “somatotonic” (with domination of the sympatholytic effects), “atonic” (balanced type of vegetative nervous system).Based on the analysis of psychodynamic, neurodynamic and vegetative functions showed that students with initial vagotonies tone are characterized by high levels of situational and personal anxiety, low psychosocial adaptation, decreased activity of neurodynamic functions and psychodynamic processes in the learning dynamics, whereas the individuals with dominance of sympatotonics type regulation have high level of neurodynamic processes, psychosocial adaptation, against the background of significant stress mechanisms of vegetative regulation.Students with initial vegetative tone demonstrate a sufficient level of psychosocial adaptation, activity psychodynamic and neuromotor processes, accompanied by the preservation of the functionality of the body according to the parameters myocardial-hemodynamic homeostasis.It is established that the formation process of psychosocial and physiological adaptation and disadaptation of students is largely determined by the type of vegetative (autonomic) tone, degree of stress, behaviour strategies in stressful situations.Целью проведенного среди учащихся в возрасте от 12 до 15 лет исследования явилось выявление интегративных критериев показателей, позволяющих оценить характер функциональных взаимосвязей между параметрами психосоциальной и физиологической адаптации учащихся в зависимости от возрастных, индивидуально-типологических особенностей вегетативной регуляции, личностного потенциала на различных этапах обучения школьников.Изучение особенностей вегетативной регуляции сердечно-сосудистой системы проводилось по показателям автоматизированной кардиоритмографической программы. Исследование психофизиологических показателей осуществлялось при помощи автоматизированного комплекса, также было произведено измерение скорости простой зрительно-моторной реакции, реакции на движущийся объект, уровня функциональной подвижности нервных процессов и работоспособности головного мозга. Особенности психосоциальной адаптации анализировались при помощи восьмицветового теста Люшера.Все обследуемые лица на основании статистических характеристик сердечного ритма были разделены на три группы по тону исходного вегетативного тонуса: «ваготоников» (с преобладанием парасимпатической готовности), «симпатотоников» (с доминированием симпатолитических воздействий), «эйтоников» (сбалансированный тип вегетативной нервной системы).На основании исследования психодинамических, нейродинамических и вегетативных функций показано, что учащиеся с исходным ваготоническим тонусом характеризуются высоким уровнем ситуативной и личностной тревожности, низкой психосоциальной адаптацией, снижением активности нейродинамических функций и психодинамических процессов в динамике обучения, тогда как у лиц с доминированием симпатотонического типа регуляции отмечается высокий уровень нейродинамических процессов, психосоциальной адаптации на фоне выраженного напряжения механизмов вегетативной регуляции эйтонических.Школьники с исходным вегетативным тонусом демонстрируют достаточный уровень психосоциальной адаптации, активности психодинамических и нейромоторных процессов, сопровождающихся сохранением функциональных возможностей организма, судя по параметрам миокардиально-гемодинамического гомеостаза

Very large scale correlations in the galaxy distribution

We characterize galaxy correlations in the Sloan Digital Sky Survey by measuring several moments of galaxy counts in spheres. We firstly find that the average counts grows as a power-law function of the distance with an exponent D= 2.1+- 0.05 for r in [0.5,20] Mpc/h and D = 2.8+-0.05 for r in [30,150] Mpc/h. In order to estimate the systematic errors in these measurements we consider the counts variance finding that it shows systematic finite size effects which depend on the samples sizes. We clarify, by making specific tests, that these are due to galaxy long-range correlations extending up to the largest scales of the sample. The analysis of mock galaxy catalogs, generated from cosmological N-body simulations of the standard LCDM model, shows that for r<20 Mpc/h the counts exponent is D~2.0, weakly dependent on galaxy luminosity, while D=3 at larger scales. In addition, contrary to the case of the observed galaxy samples, no systematic finite size effects in the counts variance are found at large scales, a result that agrees with the absence of large scale, r~100 Mpc/h, correlations in the mock catalogs. We thus conclude that the observed galaxy distribution is characterized by correlations, fluctuations and hence structures, which are larger, both in amplitude and in spatial extension, than those predicted by the standard model LCDM of galaxy formation.Comment: 6 pages, 7 figures to be published in Europhysics Letter

Clustering of photometric luminous red galaxies I : Growth of Structure and Baryon Acoustic Feature

The possibility of measuring redshift space (RSD) distortions using photometric data have been recently highlighted. This effect complements and significantly alters the detectability of baryon acoustic oscillations (BAO) in photometric surveys. In this paper we present measurements of the angular correlation function of luminous red galaxies (LRGs) in the photometric catalog of the final data release (DR7) of the Sloan Digital Sky Survey II (SDSS). The sample compromise ~ 1.5 x 10^6 LRGs distributed in 0.45 < z < 0.65, with a characteristic photometric error of ~ 0.05. Our measured correlation centered at z=0.55 is in very good agreement with predictions from standard LCDM in a broad range of angular scales, $0.5^\circ < \theta < 6^\circ$. We find that the growth of structure can indeed be robustly measured, with errors matching expectations. The velocity growth rate is recovered as $f \sigma_8 = 0.53 \pm 0.42$ when no prior is imposed on the growth factor and the background geometry follows a LCDM model with WMAP7+SNIa priors. This is compatible with the corresponding General Relativity (GR) prediction $f \sigma_8 = 0.45$ for our fiducial cosmology. If we adopt a parametrization such that $f=\Omega ^\gamma_m(z)$, with $\gamma \approx 0.55$ in GR, and combine our $f\sigma_8$ measurement with the corresponding ones from spectroscopic LRGs at lower redshifts we obtain $\gamma=0.54 \pm 0.17$. In addition we find evidence for the presence of the baryon acoustic feature matching the amplitude, location and shape of LCDM predictions. The photometric BAO feature is detected with 98 % confidence level at z=0.55.Comment: 16 pages, 19 figures, minor changes to text to match accepted version by MNRA

A Strategy to Measure the Dark Energy Equation of State using the HII galaxy Hubble Relation & X-ray AGN Clustering: Preliminary Results

We explore the possibility of setting stringent constraints to the Dark Energy equation of state using alternative cosmic tracers like: (a) the Hubble relation using HII galaxies, which can be observed at much higher redshifts (z~3.5) than those currently traced by SNIa samples, and (b) the large-scale structure using the clustering of X-ray selected AGN,which have a redshift distribution peaking at z~1. We use extensive Monte-Carlo simulations to define the optimal strategy for the recovery of the dark-energy equation of state using the high redshift (z~2) Hubble relation, but accounting also for the effects of gravitational lensing, which for such high redshifts can significantly affect the derived cosmological constraints. Based on a "Figure of Merit" analysis, we provide estimates for the number of 2<z<3.5 tracers needed to reduce the cosmological solution space, presently provided by the Constitution SNIa set, by a desired factor. We find that it is much more efficient to increase the number of tracers than to reduce their individual uncertainties. Finally, we propose a framework to put constraints on the dark energy equation of state by using the joint likelihood of the X-ray AGN clustering and of the Hubble relation cosmological analyses. A preliminary joint analysis using the X-ray AGN clustering of the 2XMM survey and the Hubble relation of the Constitution SNIa set provide: Omega_m= 0.31+-0.01 and w=-1.06+-0.05. We also find that the joint SNIa-2XMM analysis provides significantly more stringent cosmological constraints, increasing the Figure of Merit by a factor ~2, with respect to that of the joint SNIa-BAO analysis.Comment: MNRAS in press, 12 colour figure