Power management and distribution considerations for a lunar base

Design philosophies and technology needs for the power management and distribution (PMAD) portion of a lunar base power system are discussed. A process is described whereby mission planners may proceed from a knowledge of the PMAD functions and mission performance requirements to a definition of design options and technology needs. Current research efforts at the NASA LRC to meet the PMAD system needs for a Lunar base are described. Based on the requirements, the lunar base PMAD is seen as best being accomplished by a utility like system, although with some additional demands including autonomous operation and scheduling and accurate, predictive modeling during the design process

A synthetic and computational approach to the design of new photoactive organometallic materials.

Chapter one serves as an introduction to organometallic chemistry, specifically metal carbonyl complexes. The principles of photophysics are also introduced. This is followed by an outline of the techniques of matrix isolation and time-resolved infrared (TRIR) spectroscopy. The rapidly developing area of computational chemistry is then introduced. Specific emphasis is placed on the ab-intio and Density Functional Theory (DFT) levels of theory as well as the method of Time-dependent Density Functional Theory (TDDFT), used for predicting excited states. Chapter two begins with an introduction to the properties of the carbon-fluorine bond and a short review of recent reports of C-F bond activation in the literature. This is followed by a literature survey, which focuses on photochemistry and computational studies of a number of metal carbonyl compounds. The photochemistry of a series of fluorinated metal carbonyls of the type XMn(CO)5 (X = fluorinated substituent), was probed via matrix isolation studies at 20 K, using both IR and UV-vis as detectionmethods. Theoretical studies were performed, and compared to the experimental data. Chapter three involves a review of the photochemistry of M(C0)5 systems, where M = W, Cr, bound to pyridine or substituted pyridines. The photochemistry of systems of the type FpyW(CO)5, as then investigated using matrix isolation at 20 K in a number of matrix gases. Spectroscopic changes were monitored via UV-Vis and IR spectroscopy. Theoretical studies using TDDFT were also preformed. These are compared to the experimental data observed in matrix isolation studies. Chapter four begins with a review of the literature of cis-trans/trans-cis isomerisation, particularly in stilbene and butadiene type compounds. This is then followed by a literature review of the photochemistry of (arene)M(CO)s type compounds. For comparison a review of the photochemistry of a number of photoisomerisable Re(C0)3L complexes is also included, as these systems contain both isomerisable stilbene-like units and carbonyl units. .Predominantly the chapter centres on the photoinduced cis-trans isomerisation of ci~-(~~-1,2-di~hen~lethene)~r(~T0)h3e. photochemistry of these compounds is then examined using techniques such as, matrix isolation, time resolved infia red (TRLR) spectroscopy, and steady-state photolysis. These results are then compared to theoretical results achieved using quantum chemical calculations. The electrochemistry of these metal carbonyl systems is then briefly examined. Chapter five begins with a general introduction to Sonogashira-Hagihara type cross coupling reactions. This is then followed by a literature survey on the synthesis and photochemistry of luminescent organometallic dyad systems. The synthesis of these novel systems using the Sonogashira-Hagihara method is described. The photophysical properties are then examined using room and low temperature fluorescence and life-time studies. The photochemistry of the C02(C0)6 complexes are examined by steady-state photolysis studies in the presence of a trapping ligand. Electrochemical data is also included. Chapter six involves the study of organometallic pyrenyl-ferrocenyl dyad systems. This chapter begins with a brief review of the literature of organometallic ferrocene compounds as luminescent pyrenyl dyad systems are discussed in detail in chapter four. The effect, on the excited state, of the ferrocenyl moiety and the level of conjugation present is examined using fluorescence spectroscopy and electrochemistry. The results of photoinduced CO loss of the Co2(C0)6 complexes in the presence of the trapping ligand triphenylphisphine and are also discussed. Appendix: Experimental details for a number of metal carbonyl complexes and cyclopentenone complexes formed by a photochemically induced Pauson-Khand reaction. Matrix isolation sample preparation and matrix isolation studies for (n6-phenanthrene)Cr(CO)a~re also discussed

Use of an audio-paced incremental swimming test in young national-level swimmers

Purpose:To evaluate the reliability and sensitivity to training of an audio-paced incremental swimming test.Methods:Eight young national-level male swimmers (age 15 ± 1 year) performed a 7 × 200-m incremental swimming test (velocities 1.19, 1.24, 1.28, 1.33, 1.39, and 1.45 m/s and maximal sprint pace) using an audio-pacing device. The same test was performed 4 times by each participant, 1 wk apart to assess reliability (WK1, WK2) and after 9 and 20 wk of training (WK9, WK20). Blood lactate concentration ([La−]) and heart rate (HR) were recorded after each stage. Outcome measures were the velocity (v) and HR at lactate markers of 2 mM, 4 mM, and Δ1 mM.Results:Velocities at the lactate markers proved to be more reliable than HR, with typical errors ranging from 0.66% to 2.30% and 1.28% to 4.50%, respectively (shifts in mean ranged –0.91% to 0.73% and –0.84% to 1.79%, respectively). Across WK1, WK9, and WK20 there were significant improvements in peak velocity (P &lt; .001) and each of the velocities associated with the lactate markers (P &lt; .05), whereas only HR at Δ1 mM improved (P &lt; .05).Conclusions:This article demonstrates that an audio-paced incremental swimming test is reliable for use with junior swimmers and is sensitive to changes observed after training. The postswimming measurement of HR in the pool was comparatively less reliable.</jats:sec

Racial Differences in Hypertension Claims Rates for Medicaid Patients: Has it Changed Since 1991?

The purpose of this study was to determine whether the racial differences hypertension claim rates for Medicaid patients has changed since 1991. Age-specific and age-adjusted prevalence rates of hypertension in 2015, and the first 2015 claim rates by race and gender were calculated and compared to age-specific and age-adjusted prevalence rates of hypertension in 1991 and the first 1991 claim rates by race and gender. Gender-specific black-to-white risk ratios were also calculated. The comparison reveled that in both study groups, African-American females were more likely than African-American males, or whites of either sex to have hypertension diagnoses. Using Medicaid data from 12 unknown states for the 2015 calculations represented a significant limitations due to the possibility that any, most, or all of the 12 states could be excluded from the stroke belt, as well as the early 20th century phenomena such as the Great Migration, which may have caused underestimation of comparison in the prevalence and incidence of hypertension among Medicaid recipients in 2015; however, significant racial differences in the occurrence of hypertension still existed among them

Life-history and ecology of the greenback cutthroat trout

Prepared for: the Greenback Cutthroat Trout Recovery Team.Includes bibliographical references

Macroeconomic and Industry Determinants of Interest Rate Spread-Empirical Evidence

This paper examines bank-specific, industry-specific and macroeconomic factors that influence interest rate spreads (IRS) in commercial banks in Ghana using unbalanced panel data set from 33 commercial banks covering the 21-year period 1990 to 2010. The study employed annual time series data from 1990 to 2010. Results suggest that interest rate spread in Ghana is significantly influenced by bank- specific and macroeconomic variables. These are bank ownership, Management inefficiency, Gross Domestic Product Per Capita (GDPPC) and Government Securities which all have positive relationship with IRS. Government borrowing on the other hand also influences IRS significantly but has a negative effect. The paper's findings are important for central banks, the commercial banks and managers of the economy for efficiency and effectiveness. The paper is the first of its kind in Ghana a developing country with emphasis on macroeconomic variables. Keywords: Ghana, Interest Rate Spread, Bank-specific factors, Industry-Specific factors, Macroeconomic variable

Emerging technologies of polymeric nanoparticles in cancer drug delivery

Polymeric nanomaterials have the potential to improve upon present chemotherapy delivery methods. They successfully reduce side effects while increasing dosage, increase residence time in the body, offer a sustained and tunable release, and have the ability to deliver multiple drugs in one carrier. However, traditional nanomaterial formulations have not produced highly therapeutic formulations to date due to their passive delivery methods and lack of rapid drug release at their intended site. In this paper, we have focused on a few “smart” technologies that further enhance the benefits of typical nanomaterials. Temperature and pHresponsive drug delivery devices were reviewed as methods for triggering release of encapsulating drugs, while aptamer and ligand conjugation were discussed as methods for targeted and intracellular delivery, with emphases on in vitro and in vivo works for each method

The Development of a Highly Reliable Power Management and Distribution System for Civil Transport Aircraft

NASA is pursuing a program in Advanced Subsonic Transport (AST) to develop the technology for a highly reliable Fly-By-Light/Power-By-WIre aircraft. One of the primary objectives of the program is to develop the technology base for confident application of integrated PBW components and systems to transport aircraft to improve operating reliability and efficiency. Technology will be developed so that the present hydraulic and pneumatic systems of the aircraft can be systematically eliminated and replaced by electrical systems. These motor driven actuators would move the aircraft wing surfaces as well as the rudder to provide steering controls for the pilot. Existing aircraft electrical systems are not flight critical and are prone to failure due to Electromagnetic Interference (EMI) (1), ground faults and component failures. In order to successfully implement electromechanical flight control actuation, a Power Management and Distribution (PMAD) System must be designed having a reliability of 1 failure in 10(exp +9) hours, EMI hardening and a fault tolerance architecture to ensure uninterrupted power to all aircraft flight critical systems. The focus of this paper is to analyze, define, and describe technically challenging areas associated with the development of a Power By Wire Aircraft and typical requirements to be established at the box level. The authors will attempt to propose areas of investigation, citing specific military standards and requirements that need to be revised to accommodate the 'More Electric Aircraft Systems'

Asset quality in a crisis period: An empirical examination of Ghanaian banks

AbstractThis paper examines the factors that account for the deterioration in the asset quality of Ghanaian banks during a period of financial crises using a unique dataset on 25 banks from 2005 to 2010. Based on system Generalized Method of Moments estimations, we find that the persistence of non-performing loans in addition to loan growth, bank market structure, bank size, inflation, real exchange rate and GDP growth are the significant determinants of banks asset quality in Ghana. The findings have implications for both bank management and regulators in emerging economies