LADEE Satellite Modeling and Simulation Development

As human activity on and around the Moon increases, so does the likelihood that our actions will have an impact on its atmosphere. The Lunar Atmosphere and Dust Environment Explorer (LADEE), a NASA satellite scheduled to launch in 2013, will orbit the Moon collecting composition, density, and time variability data to characterize the current state of the lunar atmosphere. LADEE will also test the concept of the "Modular Common Bus" spacecraft architecture, an effort to reduce both development time and cost by designing reusable, modular components for use in multiple missions with similar requirements. An important aspect of this design strategy is to both simulate the spacecraft and develop the flight code in Simulink, a block diagram-style programming language that allows easy algorithm visualization and performance testing. Before flight code can be tested, however, a realistic simulation of the satellite and its dynamics must be generated and validated. This includes all of the satellite control system components such as actuators used for force and torque generation and sensors used for inertial orientation reference. My primary responsibilities have included designing, integrating, and testing models for the LADEE thrusters, reaction wheels, star trackers, and rate gyroscopes

Assessment of desalination treatment processes for future water supplies

Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2003.Includes bibliographical references (leaves 65-67).by Chad Howard Stevens.M.Eng

A culture-based entrepreneurship program: Impact on student interest in business ownership

This paper reports the results of a study that examined the impact of a culture-based entrepreneurship study abroad program on interest in business ownership. Forty-three students were asked to complete a pre and post program questionnaire that asked about their understanding of a variety of program activities and to gauge their interest in starting a business. Almost no similar research has been reported in the literature. Pre- and postprogram mean rankings of the variables are reported The results indicated that post-program mean rankings tend to be higher than pre-program mean rankings. Twelve of the post-program mean values are significantly different from pre-program mean values. Logit regression analysis indicated that the culture variable was positively associated with interest in starting a business while the Spanish business and entrepreneurial skills, and program structure variables were negatively associated with business ownership. The results of this study may be of interest to educators involved in developing entrepreneurship and study abroad courses and programs. The study may be of special interest to those involved in developing integrative entrepreneurship programs

Evidence for the Direct Detection of the Thermal Spectrum of the Non-Transiting Hot Gas Giant HD 88133 b

We target the thermal emission spectrum of the non-transiting gas giant HD 88133 b with high-resolution near-infrared spectroscopy, by treating the planet and its host star as a spectroscopic binary. For sufficiently deep summed flux observations of the star and planet across multiple epochs, it is possible to resolve the signal of the hot gas giant's atmosphere compared to the brighter stellar spectrum, at a level consistent with the aggregate shot noise of the full data set. To do this, we first perform a principal component analysis to remove the contribution of the Earth's atmosphere to the observed spectra. Then, we use a cross-correlation analysis to tease out the spectra of the host star and HD 88133 b to determine its orbit and identify key sources of atmospheric opacity. In total, six epochs of Keck NIRSPEC L band observations and three epochs of Keck NIRSPEC K band observations of the HD 88133 system were obtained. Based on an analysis of the maximum likelihood curves calculated from the multi-epoch cross correlation of the full data set with two atmospheric models, we report the direct detection of the emission spectrum of the non-transiting exoplanet HD 88133 b and measure a radial projection of the Keplerian orbital velocity of 40 $\pm$ 15 km/s, a true mass of 1.02$^{+0.61}_{-0.28}M_J$, a nearly face-on orbital inclination of 15${^{+6}_{-5}}^{\circ}$, and an atmosphere opacity structure at high dispersion dominated by water vapor. This, combined with eleven years of radial velocity measurements of the system, provides the most up-to-date ephemeris for HD 88133.Comment: 9 pages, 6 figures; accepted for publication in Ap

Effects of Telluric Contamination in Iodine-calibrated Precise Radial Velocities

We characterized the effects of telluric absorption lines on the radial velocity (RV) precision of stellar spectra taken through an iodine cell. To isolate the effects induced by telluric contamination from other stellar, instrumental, or numerical systematic RV noise, we extracted RVs from simulated iodine-calibrated spectra of three RV standard stars regularly observed by Keck/HIRES. We add in water absorption lines according to measured precipitable water vapor (PWV) contents over a one-year period. We conclude that telluric contamination introduces additional RV noise and spurious periodic signals at the level of 10–20 cm s⁻¹, consistent with similar previous studies. Our findings show that forward modeling the telluric lines effectively recovers the RV precision and accuracy, with no prior knowledge of the PWV needed. Such a recovery is less effective when the water absorption lines are relatively deep in the stellar template used in the forward modeling. Overall, telluric contamination plays an insignificant role in typical iodine-calibrated RV programs aiming at ~1–2 m s⁻¹, but we recommend adding modeling of telluric lines and taking stellar template observations on nights with low humidity for programs aiming to achieve a precision of better than 1 m s⁻¹

A Comparison of Association Methods for Cytotoxicity Mapping in Pharmacogenomics

Cytotoxicity assays of immortalized lymphoblastoid cell lines (LCLs) represent a promising new in vitro approach in pharmacogenomics research. However, previous studies employing LCLs in gene mapping have used simple association methods, which may not adequately capture the true differences in non-linear response profiles between genotypes. Two common approaches summarize each dose-response curve with either the IC50 or the slope parameter estimates from a hill slope fit and treat these estimates as the response in a linear model. The current study investigates these two methods, as well as four novel methods, and compares their power to detect differences between the response profiles of genotypes under a variety of different alternatives. The four novel methods include two methods that summarize each dose-response by its area under the curve, one method based off of an analysis of variance (ANOVA) design, and one method that compares hill slope fits for all individuals of each genotype. The power of each method was found to depend not only on the choice of alternative, but also on the choice for the set of dosages used in cytotoxicity measurements. The ANOVA-based method was found to be the most robust across alternatives and dosage sets for power in detecting differences between genotypes

Turnover-Dependent Inactivation of the Nitrogenase MoFe-Protein at High pH

Proton uptake accompanies the reduction of all known substrates by nitrogenase. As a consequence, a higher pH should limit the availability of protons as a substrate essential for turnover, thereby increasing the proportion of more highly reduced forms of the enzyme for further study. The utility of the high-pH approach would appear to be problematic in view of the observation reported by Pham and Burgess [(1993) Biochemistry 32, 13725–13731] that the MoFe-protein undergoes irreversible protein denaturation above pH 8.65. In contrast, we found by both enzyme activity and crystallographic analyses that the MoFe-protein is stable when incubated at pH 9.5. We did observe, however, that at higher pHs and under turnover conditions, the MoFe-protein is slowly inactivated. While a normal, albeit low, level of substrate reduction occurs under these conditions, the MoFe-protein undergoes a complex transformation; initially, the enzyme is reversibly inhibited for substrate reduction at pH 9.5, yet in a second, slower process, the MoFe-protein becomes irreversibly inactivated as measured by substrate reduction activity at the optimal pH of 7.8. The final inactivated MoFe-protein has an increased hydrodynamic radius compared to that of the native MoFe-protein, yet it has a full complement of iron and molybdenum. Significantly, the modified MoFe-protein retains the ability to specifically interact with its nitrogenase partner, the Fe-protein, as judged by the support of ATP hydrolysis and by formation of a tight complex with the Fe-protein in the presence of ATP and aluminum fluoride. The turnover-dependent inactivation coupled to conformational change suggests a mechanism-based transformation that may provide a new probe of nitrogenase catalysis

To bend or not to bend – are heteroatom interactions within conjugated molecules effective in dictating conformation and planarity?

We consider the roles of heteroatoms (mainly nitrogen, the halogens and the chalcogens) in dictating the conformation of linear conjugated molecules and polymers through non-covalent intramolecular interactions. Whilst hydrogen bonding is a competitive and sometimes more influential interaction, we provide unambiguous evidence that heteroatoms are able to determine the conformation of such materials with reasonable predictability

SYSTEMS ANALYSIS OF ARMY MATERIEL REPORTING FOR THE MIDDLE TIER OF ACQUISITION PATHWAY

The Acquisition Modernization Integration (AMI) team within the ASA(ALT) office is critical in the Army decision-making process. The AMI creates reports that include actionable knowledge rendered to Army strategic leaders. These reports include vital data on critical Army programs integrated into the modernization efforts. Part of this necessary data are the First Unit Issued (FUI) and the First Unit Equipped (FUE) dates. These reported dates directly affect Army units’ training, deployment, and logistics support timelines as they become part of the data-driven analytics on reports provided to decision-makers. Because of the initiatives to improve efficiency in the acquisition process, realignment, and creation of new organizations, the AMI needs a system that facilitates accurate and consistent FUI and FUE dates reporting. This research used several systems engineering (SE) concepts and methods such as stakeholders’ analysis, functional analysis, mapping of functions to systems’ parameters, modeling-based systems engineering, and analysis of alternatives. The application of these SE tools resulted in identifying a system/process that will accurately and consistently facilitate FUI and FUE date reporting to meet the AMI’s needs. This system/process provides a reporting capability for current and future acquisition programs and could be implemented across the DOD and all other government agencies and departments.Major, United States ArmyCaptain, United States ArmyCaptain, United States ArmyCaptain, United States ArmyCaptain, United States ArmyApproved for public release. Distribution is unlimited

Texas 4-H Quiz Bowl Guide

86 pp., 2 figuresDeveloped to help 4-H project leaders develop and run a quiz bowl, this publication covers the philosophy of instruction and competition, quiz bowl basics, contest rules, team selection, site criteria, equipment and supplies, team preparation, job descriptions, question development and elimination tournaments