Effects of aircraft noise on flight and ground structures

Acoustic loads measured on jet-powered STOL configurations are presented for externally blown and upper surface blown flap models ranging in size from a small laboratory model up to a full-scale aircraft model. The implications of the measured loads for potential acoustic fatigue and cabin noise are discussed. Noise transmission characteristics of light aircraft structures are presented. The relative importance of noise transmission paths, such as fuselage sidewall and primary structure, is estimated. Acceleration responses of a historic building and a residential home are presented for flyover noise from subsonic and supersonic aircraft. Possible effects on occupant comfort are assessed. The results from these three examples show that aircraft noise can induce structural responses that are large enough to require consideration in the design or operation of the aircraft

Thermal and Non-thermal Plasmas in the Galaxy Cluster 3C 129

We describe new Chandra spectroscopy data of the cluster which harbors the prototypical "head tail" radio galaxy 3C 129 and the weaker radio galaxy 3C 129.1. We combined the Chandra data with Very Large Array (VLA) radio data taken at 0.33, 5, and 8 GHz (archival data) and 1.4 GHz (new data). We also obtained new HI observations at the Dominion Radio Astrophysical Observatory (DRAO) to measure the neutral Hydrogen column density in the direction of the cluster with arcminute angular resolution. The Chandra observation reveals extended X-ray emission from the radio galaxy 3C 129.1 with a total luminosity of 1.5E+41 erg/s. The X-ray excess is resolved into an extended central source of ~2 arcsec (1 kpc) diameter and several point sources with an individual luminosity up to 2.1E+40 erg/s. In the case of the radio galaxy 3C 129, the Chandra observation shows, in addition to core and jet X-ray emission reported in an earlier paper, some evidence for extended, diffuse X-ray emission from a region east of the radio core. The 12 arcsec x 36 arcsec (6 kpc x 17 kpc) region lies "in front" of the radio core, in the same direction into which the radio galaxy is moving. We use the radio and X-ray data to study in detail the pressure balance between the non-thermal radio plasma and the thermal Intra Cluster Medium (ICM) along the tail of 3C 129 which extends over 15 arcmin (427 kpc). Depending on the assumed lower energy cutoff of the electron energy spectrum, the minimum pressure of the radio plasma lies a factor of between 10 and 40 below the ICM pressure for a large part of the tail. We discuss several possibilities to explain the apparent pressure mismatch.Comment: Accepted for publication in MNRAS. Refereed manuscript. 14 pages, 8 figures, additional panel of Fig. 3 shows asymmetric ICM distributio

Anaerobic Nitrogen Fixation in Some Iowa Soils

Data secured by various investigators have proven quite conclusively that the aerobic nitrogen-fixing bacteria of the genus Azotobacter are not active or even present in soils more acid than pH 6.0. Many of the soils in Iowa are more strongly acid than this, and while no Azotobacter have been found in them, some nitrogen fixation certainly occurs. It appears, therefore, that some other organisms or groups of organisms must be responsible

ULEAD: The Effects of a Civics-Based Educational Program on Urban Youth

ABSTRACT Urban Legal Education and Academic Development: The Effects of a Civics-Based Educational Program on Urban Youth There is a critical need for urban youth to have working knowledge of the legal and civic nuances of their communities and political state that affects their daily lives. The pressing problems of the daily existence that these students face inhibit them from utilizing this understanding to exhibit appropriate behavior and engage in civil discourse. Urban Legal Education and Academic Development (ULEAD) provided these students with the knowledge of the functions of the legal and civic processes that facilitate behavior modification to allow them to take advantage of the social order in which they are enmeshed. Through hands-on, interactive and problem-based curricula, ULEAD presented to urban youth positive and productive ways to engage their communities and respond in socially acceptable ways to modulate the forces that they identified as oppressive. ULEAD offered young minds pathways to character development through first-hand involvement with law enforcement, judicial systems, constitutional history and socio-economic structures. The program provided students the opportunity to understand that they are part of the process that makes their communities work for the betterment of all. Students were presented with options they may never have considered to strengthen their academic, social and economic states. The ULEAD intervention demonstrated that attitudes, sense of agency, and civic understanding of urban youth could be influenced

Non-degenerate four-wave mixing in rubidium vapor: transient regime

We investigate the transient response of the generated light from Four-Wave Mixing (FWM) in the diamond configuration using a step-down field excitation. The transients show fast decay times and oscillations that depend on the detunings and intensities of the fields. A simplified model taking into account the thermal motion of the atoms, propagation, absorption and dispersion effects shows qualitative agreement with the experimental observations with the energy levels in rubidium (5S1/2, 5P1/2, 5P3/2 and 6S1/2). The atomic polarization comes from all the contributions of different velocity classes of atoms in the ensemble modifying dramatically the total transient behavior of the light from FWM.Comment: 11 pages, 11 figures, to be published in Physical Review

Effects of propeller rotation direction on airplane interior noise levels

Interior noise measurements for upsweeping and downsweeping movement of the propeller blade tips past the fuselage were made on a twin-engine airplane and on two simplified fuselage models. Changes in interior noise levels of as much as 8 dB reversal of propeller rotation direction were measured for some configurations and test conditions

Design study of the deepsky ultraviolet survey telescope

Preliminary mechanical design and specifications are presented for a wide field ultraviolet telescope and detector to be carried as a Spacelab payload. Topics discussed include support structure stiffness (torsional and bending), mirror assembly, thermal control, optical alignment, attachment to the instrument pointing pallet, control and display, power requirements, acceptance and qualification test plans, cost analysis and scheduling. Drawings are included

Sex and the Cinema: What American Pie Teaches the Young

This paper focuses upon the wildly successful blockbuster American Pie teenpics, especially American Pie 3 – the Wedding. I argue that these films, which are sited so securely within the visual and pedagogical machinery of Hollywood culture, are specifically designed to appeal to teenage male audiences, and to provide lessons in sex and romance. Movies like this are especially important as they are experienced by far more teenagers than, for example, instructional films or other classroom materials; indeed, as Henry Giroux has observed, "teens and youth learn how to define themselves outside of the traditional sites of instruction, such as the home and the school… Learning in the postmodern age is located elsewhere – in popular spheres that shape their identities, through forms of knowledge and desires that appear absent from what is taught in schools" (Giroux, 1997, p.49). In this paper I discuss whether the American Pie series is actually a "new age" effort which, via insubordinate performances of gender, contests the hegemonic field of signification which regulates the production of sex, gender and desire, or whether it is more accurately described as a retrogressive hetero-conservative opus with a veneer of sexual radicalism. In short, I intend to probe whether this filmic vector for sex education is all about the shaping of responsible, caring, vulnerable men, or is it guiding them to become just like their heterosexual, middle-class fathers? And whether, despite its riotous and raunchy advertising, American Pie really dishes up something spicy or something terribly wholesome instead

Regional Development: An Econometric Study of the Role of Water Development in Effectuating Population and Income Changes

Twelve measures of regional economic growth, including populations and three measures of income were compared for areas with and without water investment in 246 counties and 42 water resources subareas in the states of Utah, Colorado, New Mexico, Montana, Wyoming, Idaho, and Nevada. Simple mean omparisons for these measures compiled for the decades of 1940-1950, 1950-1960, and 1960-1970 failed to support the hypothesis that economic growth of those counties and subareas receiving water investment was significantly highter than in those areas which did not, with the possible exception of the 1940-1950 decade. This result is obciously tempered by the fact that with-without comparisons taken on a cross-sectional basis may be inaccurage to the extent that spatial units used in the analysis are not homogenous in all respects but the presence or absence of water investment. Population, farm income, median family income, and per acre agricultural land values as measures of economic growth were regressed on various classes of water investment (Total, M&1, Recreation, and Irrigation investment, and other related variables) for the spatial units. Results obtained from this analysis were inconclusive with respect to the hypothesized role of water investment in effectuating economic growth. For small areas in New Mexico where more detailed records of water investment were available, a nine equation econometric model was estimated using a three-stage least squares analysis. As specified, this model facilitated an examination of the interactive effect of water development as a causal variable and as an endogenous variable which responds to other growth inducements. Test statistics for multi-equation systems are only indicative, and the statistical results were nonconclusive, although expected signs on the coefficients were obtained in most instances. Input-output and economic base-models were used to examine two case studies of water investment in Western Coloado. The objective was to demonstrate the methodology and the magnitudes of change in regional economic activity (gross regional output, exports, income, and employment) which could be associated with major irrigation-type water developments. In this analysis it was found that total gross output attributable to the projects ranged from zero in the petroleum and mining sectors to a high of 260,302 in the dairy industry. Multiplicative effects on employment income and gross economic activity ranged from 1.06 to 2.30 times their initial magnitude. Income and employment multipliers were of similar magnitude. it should be recognized that these estimates cannot e viewed in the same manner as similar growth increments at the national level, as would typically be done, because of the strong possibility of regional offsets occurring in other regions not participating in water development. To the extent that growth in other areas is reduced by the growth of a particular region, these reductions should be subtracted from the growth measured in the latter set of regions. In all tests conducted no conclusive evidence was found taht water development causes regions to grow faster than those regions which did not receive water investment. This is not to say that growth in those regions receiving water investment was not higher than it would have been had the investment not been made. However, it does provide evidence that, an average among the regions included within this analysis, that those areas which did not receive major water investments grow at a faster rate than those which did. Thus, the input-output approach shows potential inpacts from water investment in a general equilibrium context, but rest son the assumption that other concurrent events which could produce similar or offsetting effects in the region are held constant. The cross-section analysis measures total changes in a regional economy overtime, but the multiplicity of events, other than water investment, may obscure the effects of water investment

DA495 - an aging pulsar wind nebula

We present a radio continuum study of the pulsar wind nebula (PWN) DA 495 (G65.7+1.2), including images of total intensity and linear polarization from 408 to 10550 MHz based on the Canadian Galactic Plane Survey and observations with the Effelsberg 100-m Radio Telescope. Removal of flux density contributions from a superimposed \ion{H}{2} region and from compact extragalactic sources reveals a break in the spectrum of DA 495 at 1.3 GHz, with a spectral index ${\alpha}={-0.45 \pm 0.20}$ below the break and ${\alpha}={-0.87 \pm 0.10}$ above it (${S}_\nu \propto{\nu^{\alpha}}$). The spectral break is more than three times lower in frequency than the lowest break detected in any other PWN. The break in the spectrum is likely the result of synchrotron cooling, and DA 495, at an age of $\sim$20,000 yr, may have evolved from an object similar to the Vela X nebula, with a similarly energetic pulsar. We find a magnetic field of $\sim$1.3 mG inside the nebula. After correcting for the resulting high internal rotation measure, the magnetic field structure is quite simple, resembling the inner part of a dipole field projected onto the plane of the sky, although a toroidal component is likely also present. The dipole field axis, which should be parallel to the spin axis of the putative pulsar, lies at an angle of {\sim}50\degr east of the North Celestial Pole and is pointing away from us towards the south-west. The upper limit for the radio surface brightness of any shell-type supernova remnant emission around DA 495 is $\Sigma_{1 GHz} \sim 5.4 \times 10^{-23}$ OAWatt m$^{-2}$ Hz$^{-1}$ sr$^{-1}$ (assuming a radio spectral index of $\alpha = -0.5$), lower than the faintest shell-type remnant known to date.Comment: 25 pages, accepted by Ap