Introduction of laser initiation for the 48-inch Advanced Solid Rocket Motor (ASRM) test motors at Marshall Space Flight Center (MSFC)

The Advanced Solid Rocket Motor is a new design for the Space Shuttle Solid Rocket Booster. The new design will provide more thrust and more payload capability, as well as incorporating many design improvements in all facets of the design and manufacturing process. A 48-inch (diameter) test motor program is part of the ASRM development program. This program has multiple purposes for testing of propellent, insulation, nozzle characteristics, etc. An overview of the evolution of the 48-inch ASRM test motor ignition system which culminated with the implementation of a laser ignition system is presented. The laser system requirements, development, and operation configuration are reviewed in detail

The Labor Force Participation Rate: A Rexamination Of The Determinants Of Its Decline

The U.S. Labor Force Participation Rate (LFPR) is defined as the number of people in the labor force as a percentage of the civilian noninstitutional population 16 years and over.  In a paper published in November, 2013, we examined the determinants of the decline in the LFPR from a 1998 peak of 67.2% to then, 63.3%.  Consensus of a number of economic studies at that time was that the primary determinant of the decline was cyclical and that an improving economy would stop, if not reverse, the downward trend. Since that time the unemployment rate has declined from 7.2% to 5.3%.  However, the LFPR has continued its decline to 62.6%.  Structural issues in the economy would appear to have far greater effect on LFPR decline than previously believed. In this paper we examine the following classes of structural determinants and their effects on LFPR: demographics, including not only the prime working cohort of ages 25 to 54, but also those of retirement age; the impact of a welfare system that appropriately provides a critical safety net, but one that reduces incentive to work through disability payments, extended unemployment benefits, and other subsidies;  education for both those of a higher level of attainment, as well as an underclass that no longer receives training by business, but must rely on both public and private vocational education; and finally the consequences of globalization on the economy, including the virtual disappearance of semi-skilled industries in the United States that heretofore have provided jobs for high school graduates

The Labor Force Participation Rate: An Examination Of The Determinants Of Its Recent Precipitous Decline

The Labor Force Participation Rate (LFPR) is defined as those Americans in the labor force, i.e. above the age of sixteen, below retirement age, who are either actively employed or actively seeking employment.  From 1950 until 1998 it rose from 59.2% to 67.2%.  Given the near doubling of the U.S. population, its impact on our economy was enormous.  However, since 1998 the LFPR has declined steadily to 63.3%.  Parallel to this decline, we have seen a polarization of both wealth and income in the U.S.  Many economists have examined both trends – the decline of LFPR and inequality – and have put forth a variety of determinants.  These include technology and globalization – a decline or “hollowing out” of the middle class, if you will.  Also included are the demographics of an ageing society, and the increased racial and gender participation, but also a workforce that has become only marginally prepared by today’s educational institutions.  Another class of determinants is the welfare “safety net” at both the Federal and state levels, including extended unemployment benefits, disability payments and other subsidies.  The authors examine each class of determinants, including whether their aspects are cyclical, structural or even part of an ominous trend for our economy

The Megamaser Cosmology Project. VII. Investigating disk physics using spectral monitoring observations

We use single-dish radio spectra of known 22 GHz H$_2$O megamasers, primarily gathered from the large dataset observed by the Megamaser Cosmology Project, to identify Keplerian accretion disks and to investigate several aspects of the disk physics. We test a mechanism for maser excitation proposed by Maoz & McKee (1998), whereby population inversion arises in gas behind spiral shocks traveling through the disk. Though the flux of redshifted features is larger on average than that of blueshifted features, in support of the model, the high-velocity features show none of the predicted systematic velocity drifts. We find rapid intra-day variability in the maser spectrum of ESO 558-G009 that is likely the result of interstellar scintillation, for which we favor a nearby ($D \approx 70$ pc) scattering screen. In a search for reverberation in six well-sampled sources, we find that any radially-propagating signal must be contributing $\lesssim$10% of the total variability. We also set limits on the magnetic field strengths in seven sources, using strong flaring events to check for the presence of Zeeman splitting. These limits are typically 200--300 mG ($1\sigma$), but our most stringent limits reach down to 73 mG for the galaxy NGC 1194.Comment: Accepted for publication in Ap

Casino Stocks and Katrina: An Example of Market Over-Reaction?

How efficient was the market in anticipating the impact of Hurricane Katrina on the Gulf coast casino industry? This study uses the event study methodology to investigate the stock market’s reaction affecting equity prices of small casino companies with operations on the Gulf Coast centered on Biloxi, Mississippi. Cumulative Abnormal Returns (CARs) for 1 day, 3 day, and 6 day event windows are examined.. As such the impact of Katrina on stock prices of casino firms in the Gulf Coast is better understood

Radio continuum of galaxies with H2_{2}O megamaser disks: 33 GHz VLA data

We investigate the nuclear environment of galaxies with observed 22 GHz water megamaser in their subparsec edge-on accretion disks, using 33 GHz (9mm) radio continuum data from VLA, with a resolution of ~ 0.2-0.5 arcsecs, and relate the maser and host galaxy properties to those of its radio continuum emission. Eighty-seven percent (21 out of 24) galaxies in our sample show 33 GHz radio continuum emission at levels of 4.5-240 $\sigma$. Five sources show extended emission, including one source with two main components and one with three main components. The remaining detected 16 sources exhibit compact cores within the sensitivity limits. Little evidence is found for extended jets (>300 pc) in most sources. Either they do not exist, or our chosen frequency of 33 GHz is too high for a detection of these supposedly steep spectrum features. In only one source among those with known maser disk orientation, NGC4388, we found an extended jet-like feature that appears to be oriented perpendicular to the water megamaser disk. Smaller 100-300 pc sized jets might also be present, as is suggested by the beam-deconvolved morphology of our sources. Whenever possible, central positions with accuracies of 20-280 mas are provided. A correlation analysis shows that the 33 GHz luminosity weakly correlates with the infrared luminosity. The 33 GHz luminosity is anticorrelated with the circular velocity of the galaxy. The black hole masses show stronger correlations with water maser luminosity than with 1.4 GHz, 33 GHz, or hard X-ray luminosities. Furthermore, the inner radii of the disks show stronger correlations with 1.4 GHz, 33 GHz, and hard X-ray luminosities than their outer radii, suggesting that the outer radii may be affected by disk warping, star formation, or peculiar density distributions.Comment: 18 pages, 10 figures, Accepted for publication in A&

Monitoring PSR B1509–58 with RXTE: Spectral analysis 1996–2010

We present an analysis of the X-ray spectra of the young, Crab-like pulsar PSR B1509–58 (pulse period P ~ 151ms) observed by RXTE over 14 years since the beginning of the mission in 1996. The uniform dataset is especially well suited for studying the stability of the spectral parameters over time as well as for determining pulse phase resolved spectral parameters with high significance. The phase averaged spectra as well as the resolved spectra can be well described by an absorbed power law

The lean oxidation of iso-octane at elevated pressures

Both spark-ignition and compression-ignition engines burn large molecular-weight blended fuels, a class to which the primary reference fuels (PRF), n-heptane and iso-octane belong. In this study experiments were performed using iso-octane in a high pressure flow reactor at a temperature of 925 K, at 3, 6 and 9 atm pressure and with a fuel/air equivalence ratio of approximately 0.05. Many hydrocarbon and oxygenated hydrocarbon intermediates were identified and quantified as a function of time. These experimental results provide a strin- gent test of the low temperature chemistry portion of a kinetic model as they emphasise the importance of alkyl radical addition to molecular oxygen and internal H-atom isomerization reactions relative to alkyl radical decomposition reactions. A detailed chemical kinetic mechanism is used to simulate these experiments. We provide comparisons of model predictions with experimentally measured species profiles and describe how each species is formed as predicted by the detailed model

School-Based Prevention Of Depressive Symptoms: A Randomized Controlled Study Of The Effectiveness And Specificity Of The Penn Resiliency Program

The authors investigated the effectiveness and specificity of the Penn Resiliency Program (PRP; J. E. Gillham, L. H. Jaycox, K. J. Reivich, M. E. P. Seligman, & T. Silver, 1990), a cognitive-behavioral depression prevention program. Children (N = 697) from 3 middle schools were randomly assigned to PRP, Control (CON), or the Penn Enhancement Program (PEP; K. J. Reivich, 1996; A. J. Shatté, 1997), an alternate intervention that controls for nonspecific intervention ingredients. Children\u27s depressive symptoms were assessed through 3 years of follow-up. There was no intervention effect on average levels of depressive symptoms in the full sample. Findings varied by school. In 2 schools, PRP significantly reduced depressive symptoms across the follow-up relative to both CON and PEP. In the 3rd school, PRP did not prevent depressive symptoms. The authors discuss the findings in relation to previous research on PRP and the dissemination of prevention programs. (PsycINFO Database Record (c) 2013 APA, all rights reserved)(journal abstract