A tow concept for the space shuttle orbiter approach and landing test

The tow concept provides the means for evaluating the orbiter aerodynamic performance and handling qualities in the same configuration as expected in actual space shuttle flight operation. A Boeing 747-100 aircraft has engine-out capability to tow the orbiter to an altitude that permits a safe orbiter approach and landing. The tow concept also provides a means for conducting a comprehensive ground test program before proceeding into the actual ALT flight operations. The implementation of the tow concept requires only a minor structural modification in the nose section of the orbiter vehicle; requires minor modifications in the 747 cargo bay; and makes use of those orbiter onboard systems installed in the ALT orbiter vehicle. The 747 wake turbulence does not constitute a problem for the orbiter during take-off or climb to altitude. The impact that the tow concept would have on the cost and schedule of the space shuttle program was not evaluated in this study

Certified Nursing Assistants’ Perceptions of Nursing Home Patient Safety Culture: Is There a Relationship to Clinical or Workforce Outcomes?: A Dissertation

Patient safety culture (PSC) is a critical factor in creating high reliability healthcare organizations. However, few studies to date have correlated PSC measures with actual safety outcomes. In particular, nursing home studies have only recently appeared in the literature. Nursing homes differ from hospitals in that the vast majority of direct care is provided by certified nursing assistants (CNAs), not licensed nurses. Thus nursing home PSC could differ in important ways from PSC in acute care institutions. This dissertation was a secondary data analysis that examined whether CNAs’ perceptions of patient safety culture were correlated with clinical outcomes in a random sample of 74 nursing homes in five randomly selected states. This study matched CNA PSC survey data using the Hospital Survey of Patient Safety Culture (HSOPSC) with Minimum Data Set (MDS), Area Resource File (ARF) and Online Survey Certification and Reporting (OSCAR) data from those same homes during the first two quarters of 2005. In the original study, 1579 nurse aides out of 2872 completed the survey, for a 55% response rate. In addition to clinical outcomes, this study examined the relationship between CNA PSC scores and staff turnover. The relationship between certain demographic variables, such as level of education, tenure as a CNA, and PSC scores was evaluated. The relationship between certain facility characteristics, such as profit status and bed occupancy was also assessed. An exploratory factor analysis of the original HSOPSC instrument was re-run for this nursing home CNA sample. Data were analyzed using Poisson regression and multilevel techniques; descriptive statistics were compiled for demographic data. Major findings from the regression analyses and combined GEE models suggest that certain factors, such as CNA turnover and LPN staffing may predict CNA PSC scores. CNA PSC scores were associated with rates of falls and restraint use, but were not associated with differences in pressure ulcer rates in this sample. Few associations for CNA PSC with individual subscales were identified. The exploratory factor analysis revealed some potential differences in how items and subscales factored in this nursing home CNA population. This dissertation represents an important step in the evaluation of CNA PSC in nursing homes and the relationship of PSC to safety outcomes. Future work on nursing home PSC and clinical and workforce outcomes is described

Total Chiral Symmetry Breaking during Crystallization: Who needs a "Mother Crystal"?

Processes that can produce states of broken chiral symmetry are of particular interest to physics, chemistry and biology. Chiral symmetry breaking during crystallization of sodium chlorate occurs via the production of secondary crystals of the same handedness from a single "mother crystal" that seeds the solution. Here we report that a large and "symmetric" population of D- and L-crystals moves into complete chiral purity disappearing one of the enantiomers. This result shows: (i) a new symmetry breaking process incompatible with the hypothesis of a single "mother crystal"; (ii) that complete symmetry breaking and chiral purity can be achieved from an initial system with both enantiomers. These findings demand a new explanation to the process of total symmetry breaking in crystallization without the intervention of a "mother crystal" and open the debate on this fascinating phenomenon. We present arguments to show that our experimental data can been explained with a new model of "complete chiral purity induced by nonlinear autocatalysis and recycling".Comment: 5 pages, 4 figures, Added reference

Aircraft energy efficiency laminar flow control wing design study

An engineering design study was performed in which laminar flow control (LFC) was integrated into the wing of a commercial passenger transport aircraft. A baseline aircraft configuration was selected and the wing geometry was defined. The LFC system, with suction slots, ducting, and suction pumps was integrated with the wing structure. The use of standard aluminum technology and advanced superplastic formed diffusion bonded titanium technology was evaluated. The results of the design study show that the LFC system can be integrated with the wing structure to provide a structurally and aerodynamically efficient wing for a commercial transport aircraft

Spin Gap of S=1/2 Heisenberg Model on Distorted Diamond Chain

We study the spin gap of the S=1/2 Heisenberg model on the distorted diamond chain, which is recently proposed to represent magnetic properties of Cu_3 Cl_6 (H_2 O)_2 2H_8 C_4 SO_2. This model is composed of stacked trimers and has three kinds of exchange interactions J_1, J_2 and J_3. Using the numerical diagonalization, we obtain a contour map of the spin gap in the J_2/J_1-J_3/J_1 plane. We argue possible values of the exchange constants based on the contour map and the observed value of the spin gap.Comment: 2 pages, 4 figure

Phase Behavior of Models with Competing Interactions

Models with competing nearest-neighbor and very long-range interactions are solved exactly for several one-dimensional cases, including the usual Ising chain (lCCI) , the X Y model (XYCI) , the transverse Ising model (TICCI), and the spherical model (SCCI). For certain ratios of the competing interaction strengths, ICCI and XYCI display triple points and two critical points in a field. In addition TICCI has an apparently enclosed phase in an H-T phase diagram; however, this phase is really paramagnetic as can be seen when an extended phase diagram is used. The extended phase diagrams for ICCI, XYCI, and TICCI display tricritical points and the tricritical exponents have different values from the usual classical values. In contrast to the rich phase behavior of the preceding models, SCCI shows very simple phase behavior, which is directly related to the ground state. Finally, the introduction of a staggered field to ICCI and a simple transformation allows reinterpretation as a metamagnetic model. Using ICCI as a guide the observability of the tricritical exponents is discussed

Ising Chain with Competing Interactions in a Staggered Field

Work on the Ising chain with competing interactions is extended to the case where a staggered field is included as well as the usual direct field. A simple transformation enables one to interpret the behavior of this model as a metamagnet. Tricritical points are found and analyzed, and the observability of the tricritical exponents, as distinguished from the usual critical exponents, is discussed