Development of new materials for turbopump bearings

The life requirement for the angular contact ball bearings in the Space Shuttle Main Engine (SSME) high pressure oxygen turbopump (HPOTP) is 7.5 hours. In actual operation, significantly shorter service life was experienced. The objective is to identify bearing materials and/or materials processing techniques offering signficant potential for extending HPOTP bearing performance life. Interactive thermomechanical analysis of the HPOTP bearing-shaft system was performed with the SHABERTH computer program. Bearing fatigue life, ball-race contact stress, heat generation rate, bulk ring temperatures and circumferential stress in the inner rings were quantified as functions of radial load, thrust load and ball-race contact friction. Criteria established from the output of this analysis are being used for material candidate selection

Synthetic aperture radar/LANDSAT MSS image registration

Algorithms and procedures necessary to merge aircraft synthetic aperture radar (SAR) and LANDSAT multispectral scanner (MSS) imagery were determined. The design of a SAR/LANDSAT data merging system was developed. Aircraft SAR images were registered to the corresponding LANDSAT MSS scenes and were the subject of experimental investigations. Results indicate that the registration of SAR imagery with LANDSAT MSS imagery is feasible from a technical viewpoint, and useful from an information-content viewpoint

Voting behaviour and public employment in Nazi Germany

This paper analyses whether the German National Socialists used economic policies to reward their voters after their rise to power in 1933. Using data on public employment in the armed forces, public administrations and related professions from the German occupational censuses in 1925, 1933 and 1939 and addressing the potential endogeneity of the National Socialist vote share in 1933 by way of an instrumental variables strategy based on a similar party in Imperial Germany 1912, I find that cities with higher National Socialist vote shares experienced a relative increase in public employment: for every additional percentage point in the vote share, the number of public employment jobs increased by around 3.5 percent. When measured relative to the total population, a one standard-deviation increase in the 1933 vote share led to an increase in the share of public employment of a quarter of a standard deviation

Age-related impairment of human T lymphocytes' activation: specific differences between CD4+ and CD8+ subsets

The relevance of physiological immune aging is of great interest with respect to determining disorders with pathologic immune function in aging individuals. In recent years, the relevance of changes in peripheral lymphocytes in age-associated neurologic diseases has become more evident. Due to the lack of immunological studies, covering more than one event after mitogenic activation, we envisaged a new concept in the present study, aiming to investigate several events, starting from T cell receptor (TCR) ligation up to T cell proliferation. In addition, we addressed the question whether changes are present in the subsets (CD4, CD8) with aging. Phosphorylation of tyrosine residues declines with increasing age in CD4+ cells. Fewer levels of CD69 positive cells after 4 h mitogenic activation, altered expression of cytokines (IL2, IFN-gamma and TNF-alpha; 22 h) and lower proliferation (72 h) were determined in aging. Moreover, it could be shown that CD8+ lymphocytes react more effectively to mitogenic stimulation with reference to CD69 expression and proliferation in both age groups (60 years old). These data indicate that T cell activation, mediated by TCR engagement, is significantly impaired in aging and both subsets are affected. However, bypassing the TCR does not fully restore T cell function, indicating that there are more mechanisms involved than impaired signal transduction through TCR only. The results will be discussed in relation to their relevance in neurodegenerative and psychiatric disorders

Clinical Research Challenges: Insight from a Pilot Study at an Academic Healthcare Center

An investigational clinical research study was conducted at an academic healthcare center evaluating memantine as an adjunct to opioid therapy for treatment of chronic low back pain. The N-Methyl-D-Aspartate (NMDA) receptor is located in pain signaling neuronal synapses of the central nervous system. The receptor binds the excitatory neurotransmitter glutamate in addition to NMDA, to increase the magnitude of the perception of pain. Memantine (Namenda©) is a highly tolerated NMDA receptor antagonist which is currently prescribed in the treatment of Alzheimer’s disease. The purpose of the non-randomized pilot study without placebo was to evaluate the use of adding memantine as an adjunctive pain medication to the regimen of patients who use an oxycodone/acetaminophen combination daily for treatment of chronic low back pain (LBP). The effect of Memantine was evaluated using diaries where patients record on a daily basis the amount of oxycodone/acetaminophen used, pain scores, and number of bowel movements. Data was to be collected for six weeks with a two-week preliminary phase, followed by a four-week treatment phase, and then analyzed. The objective is to evaluate, on a preliminary basis, whether patients benefit from addition of memantine to their daily oxycodone/acetaminophen treatment by increased analgesia, a reduction of oxycodone/acetaminophen used, and less constipation. Consequently, limitations to the process of clinical research in an academic healthcare center are evaluated as a result of reduced protected time for researchers and lack of patient participation

Doctor of Philosophy

dissertationSnow cover directly influences soil temperature (Tsoil) and water content (θ), two primary drivers of ecosystem processes such as primary production and soil biogeochemical cycling. Variations in seasonal snowpack size, duration, and other characteristics therefore have the potential to significantly impact ecosystem structure and function. In the mountain ranges of the interior western United States, a region with abundant snowfall and complex topography, there is great temporal and spatial variability in snowpack characteristics. Interactions between snow and ecosystems are poorly quantified here, and with significant hydroclimatic (and snowpack) change occurring in the western U.S., it is increasingly critical to understand how this regional snowpack variability influences ecosystem structure and function. In three complementary research projects I tested the hypothesis that seasonal snowpack characteristics influence ecohydrological and biogeochemical processes in the montane ecosystems of this region. Using data from a large network of automated snowpack monitoring stations (252 sites), I quantified interannual and spatial patterns in Tsoil and θ, and their dependence on regional snowpack variation over an 11 year period. Below-snowpack and warm season Tsoil and θ were significantly related to snowpack size, melt date, and early season snow accumulation. In a 3-year manipulative experiment I compared the impacts of aeolian dust deposition, canopy structure, and interannual snowfall variability on snowpack ablation and ecosystem processes in a subalpine conifer forest. Canopy structure had a larger impact (through interception and shading) on snow accumulation and ablation than dust addition treatments. Dust and canopy structure effects on Tsoil, θ, and ecosystem processes were small compared to the effects of interannual variability in snowpack size and melt timing. In a study of 21 conifer forests in the Wasatch and Uinta ranges of Utah, I tested whether climatic drivers, including snowpack characteristics, explained spatial patterns in soil and detrital organic matter stock size and isotopic composition (13C and 15N). The climate of these sites explained only a small portion of variability in stock sizes and isotope ratios, suggesting that site-specific factors (disturbance, species, soil texture) are predominant controllers of the production and decomposition of forest organic matter stocks

Relinquishment of Prior Residence for State Income Tax Purposes: Wishing to Change Residence Does Not Make It So

We live in an increasingly mobile and global society. Individuals move from one state to another for a variety of reasons. When the move is from a state which imposes income tax, particularly to a jurisdiction which does not, questions may arise about whether the individual remains a resident of the state from which he departed for income tax purposes. In the quest for revenue, certain states are aggressive in pursuing efforts to collect income tax from persons who claim to have changed their permanent residence.These states may assert that for income tax purposes the individual remains a resident of the state he left. This article examines the law applicable to a New York State resident who believes he established permanent residence elsewhere and may be unpleasantly surprised to find that he remains a New York State resident for income tax purposes. The distinction between residents and nonresidents of New York affects whether any income tax is owed to New York, and if taxes are due, whether taxes are to be computed on a resident’s entire income or a nonresident’s New York source income. While taxpayers with considerable income have the most at risk, states such as New York pursue taxpayers even when small sums are claimed due