The use of NASTRAN in the design of wind tunnel research aircraft

The relationship between NASTRAN and the wind tunnel model design process is discussed. Specific cases illustrating the use of NASTRAN for static, heat transfer, dynamic, and aeroelastic analyses are presented. Advantages and disadvantages of using NASTRAN are summarized

Job-related stress and burnout

Occupational stress is a topic of substantial interest to organizational researchers and managers, as well as society at large. Stress arising from work conditions can be pervasive and significant in its impact on individuals, their families and organizations. There is also a widespread belief that management of job stress is a key factor for enhancing individual performance on the job, hence increasing organizational effectiveness. Sethi and Schuler 1984 outlined four major reasons why job stress and coping have become prominent issues: a concern for individual employee health and well-being; b the financial impact on organizations including days lost due to stress-related illness; c organizational effectiveness; and d legal obligations on employers to provide safe and healthy working environments

Determinants of job satisfaction and dissatisfaction among practitioners employed in intercollegiate sport organizations

The purpose of this study was to gain insight into factors that influence job satisfaction and dissatisfaction among intercollegiate athletics department employees. Factors influencing job satisfaction could impact one’s job performance and willingness to remain in a job. When employees are satisfied with their work, they are more likely to remain at their job and successfully complete tasks in association with the job (Kaltenbaugh, 2009; Dixon & Warner, 2010). In order to gain insight with regard to factors influencing job satisfaction, five individuals who were employed within intercollegiate athletics departments participated in this study. Four of the participants worked at NCAA Division I institutions. One participant worked at an NCAA Division II institution. Two themes responsible for feelings of satisfaction and two themes connected to feelings of dissatisfaction emerged from the interview data. The themes related to satisfaction were: (a) student development and achievement and (b) workplace relationships and environment. The themes related to dissatisfaction were: (a) personnel management and (b) financial pressures /lack of resources. Further examination of perspectives and experiences of current employees could be beneficial to those who are interested in pursuing a career in this profession. Understanding the elements that contribute to job satisfaction could help upper level management attract and retain quality employees. In addition, these findings can help individuals who possess an interest in entering the sport industry be better prepared for the challenges and circumstances they might encounter

Real Estate Securities and a Filter-based, Short-term Trading Strategy

Anecdotal evidence provides overwhelming support to the belief that sophisticated real estate investors profit by timing long-run real estate cycles. This article examines the investment performance benefits that sophisticated investors may derive from short-run cycles in real estate, specifically, through the publicly traded real estate markets. Using a simple strategy that filters out noise in real estate investment trust (REIT) price reversals, this study shows that a contrarian strategy is many times more profitable than the associated execution costs. Furthermore, the study demonstrates that the REIT market has been sufficiently liquid to execute this trading strategy. This last point is directly related to the filter strategy since only REITs with large price movements satisfy the hypothetical investor’s selection criteria.

The Local Group: The Ultimate Deep Field

Near-field cosmology -- using detailed observations of the Local Group and its environs to study wide-ranging questions in galaxy formation and dark matter physics -- has become a mature and rich field over the past decade. There are lingering concerns, however, that the relatively small size of the present-day Local Group ($\sim 2$ Mpc diameter) imposes insurmountable sample-variance uncertainties, limiting its broader utility. We consider the region spanned by the Local Group's progenitors at earlier times and show that it reaches $3' \approx 7$ co-moving Mpc in linear size (a volume of $\approx 350\,{\rm Mpc}^3$) at $z=7$. This size at early cosmic epochs is large enough to be representative in terms of the matter density and counts of dark matter halos with $M_{\rm vir}(z=7) \lesssim 2\times 10^{9}\,M_{\odot}$. The Local Group's stellar fossil record traces the cosmic evolution of galaxies with $10^{3} \lesssim M_{\star}(z=0) / M_{\odot} \lesssim 10^{9}$ (reaching $M_{1500} > -9$ at $z\sim7$) over a region that is comparable to or larger than the Hubble Ultra-Deep Field (HUDF) for the entire history of the Universe. It is highly complementary to the HUDF, as it probes much fainter galaxies but does not contain the intrinsically rarer, brighter sources that are detectable in the HUDF. Archaeological studies in the Local Group also provide the ability to trace the evolution of individual galaxies across time as opposed to evaluating statistical connections between temporally distinct populations. In the JWST era, resolved stellar populations will probe regions larger than the HUDF and any deep JWST fields, further enhancing the value of near-field cosmology.Comment: 6 pages, 5 figures; MNRAS Letters, in pres

Metal-poor, Strongly Star-Forming Galaxies in the DEEP2 Survey: The Relationship between Stellar Mass, Temperature-based Metallicity, and Star Formation Rate

We report on the discovery of 28 $z\approx0.8$ metal-poor galaxies in DEEP2. These galaxies were selected for their detection of the weak [OIII]$\lambda$4363 emission line, which provides a "direct" measure of the gas-phase metallicity. A primary goal for identifying these rare galaxies is to examine whether the fundamental metallicity relation (FMR) between stellar mass, gas metallicity, and star formation rate (SFR) holds for low stellar mass and high SFR galaxies. The FMR suggests that higher SFR galaxies have lower metallicity (at fixed stellar mass). To test this trend, we combine spectroscopic measurements of metallicity and dust-corrected SFRs, with stellar mass estimates from modeling the optical photometry. We find that these galaxies are $1.05\pm0.61$ dex above the z~1 stellar mass-SFR relation, and $0.23\pm0.23$ dex below the local mass-metallicity relation. Relative to the FMR, the latter offset is reduced to 0.01 dex, but significant dispersion remains (0.29 dex with 0.16 dex due to measurement uncertainties). This dispersion suggests that gas accretion, star formation and chemical enrichment have not reached equilibrium in these galaxies. This is evident by their short stellar mass doubling timescale of $\approx100^{+310}_{-75}$ Myr that suggests stochastic star formation. Combining our sample with other z~1 metal-poor galaxies, we find a weak positive SFR-metallicity dependence (at fixed stellar mass) that is significant at 94.4% confidence. We interpret this positive correlation as recent star formation that has enriched the gas, but has not had time to drive the metal-enriched gas out with feedback mechanisms.Comment: Resubmitted to ApJ on March 6, 2015. Revised to discuss selection biases and methodologies, and address the former by including more metal-rich galaxies with robust non-detections of [OIII]4363. Primary results on FMR analyses are unchanged. Additional figures are included to illustrate selection biases; previous figures have been revised to improve presentatio

Experiences with the use of axisymmetric elements in cosmic NASTRAN for static analysis

Discussed here are some recent finite element modeling experiences using the axisymmetric elements CONEAX, TRAPAX, and TRIAAX, from the COSMIC NASTRAN element library. These experiences were gained in the practical application of these elements to the static analysis of helicopter rotor force measuring systems for two design projects for the NASA Ames Research Center. These design projects were the Rotor Test Apparatus and the Large Rotor Test Apparatus, which are dedicated to basic helicopter research. Here, a genetic axisymmetric model is generated for illustrative purposes. Modeling considerations are discussed, and the advantages and disadvantages of using axisymmetric elements are presented. Asymmetric mechanical and thermal loads are applied to the structure, and single and multi-point constraints are addressed. An example that couples the axisymmetric model to a non-axisymmtric model is demonstrated, complete with DMAP alters. Recommendations for improving the elements and making them easier to use are offered