Sunspot: A program to model the behavior of hypervelocity impact damaged multilayer insulation in the Sunspot thermal vacuum chamber of Marshall Space Flight Center

The development of a computer program to predict the degradation of the insulating capabilities of the multilayer insulation (MLI) blanket of Space Station Freedom due to a hypervelocity impact with a space debris particle is described. A finite difference scheme is used for the calculations. The computer program was written in Microsoft BASIC. Also described is a test program that was undertaken to validate the numerical model. Twelve MLI specimens were impacted at hypervelocities with simulated debris particles using a light gas gun at Marshall Space Flight Center. The impact-damaged MLI specimens were then tested for insulating capability in the space environment of the Sunspot thermal vacuum chamber at MSFC. Two undamaged MLI specimens were also tested for comparison with the test results of the damaged specimens. The numerical model was found to adequately predict behavior of the MLI specimens in the Sunspot chamber. A parameter, called diameter ratio, was developed to relate the nominal MLI impact damage to the apparent (for thermal analysis purposes) impact damage based on the hypervelocity impact conditions of a specimen

Empirical predictions of hypervelocity impact damage to the space station

A family of user-friendly, DOS PC based, Microsoft BASIC programs written to provide spacecraft designers with empirical predictions of space debris damage to orbiting spacecraft is described. The spacecraft wall configuration is assumed to consist of multilayer insulation (MLI) placed between a Whipple style bumper and the pressure wall. Predictions are based on data sets of experimental results obtained from simulating debris impacts on spacecraft using light gas guns on Earth. A module of the program facilitates the creation of the data base of experimental results that are used by the damage prediction modules of the code. The user has the choice of three different prediction modules to predict damage to the bumper, the MLI, and the pressure wall. One prediction module is based on fitting low order polynomials through subsets of the experimental data. Another prediction module fits functions based on nondimensional parameters through the data. The last prediction technique is a unique approach that is based on weighting the experimental data according to the distance from the design point

Accurate guidance with large optical equipment

Review of telescope accuracy technique, and performance criteria for ground-based optical telescope

The once and future information society

In the late twentieth century, many social scientists and other social commentators came to characterize the world as evolving into an “information society.” Central to these claims was the notion that new social uses of information, and particularly application of scientific knowledge, are transforming social life in fundamental ways. Among the supposed transformations are the rise of intellectuals in social importance, growing productivity and prosperity stemming from increasingly knowledge-based economic activity, and replacement of political conflict by authoritative, knowledge-based decision-making. We trace these ideas to their origins in the Enlightenment doctrines of Saint Simon and Comte, show that empirical support for them has never been strong, and consider the durability of their social appeal

Airborne Multidrug-Resistant Bacteria Isolated from a Concentrated Swine Feeding Operation

The use of nontherapeutic levels of antibiotics in swine production can select for antibiotic resistance in commensal and pathogenic bacteria in swine. As a result, retail pork products, as well as surface and groundwaters contaminated with swine waste, have been shown to be sources of human exposure to antibiotic-resistant bacteria. However, it is unclear whether the air within swine operations also serves as a source of exposure to antibiotic-resistant bacterial pathogens. To investigate this issue, we sampled the air within a concentrated swine feeding operation with an all-glass impinger. Samples were analyzed using a method for the isolation of Enterococcus. A total of 137 presumptive Enterococcus isolates were identified to species level using standard biochemical tests and analyzed for resistance to erythromycin, clindamycin, virginiamycin, tetracycline, and vancomycin using the agar dilution method. Thirty-four percent of the isolates were confirmed as Enterococcus, 32% were identified as coagulase-negative staphylococci, and 33% were identified as viridans group streptococci. Regardless of bacterial species, 98% of the isolates expressed high-level resistance to at least two antibiotics commonly used in swine production. None of the isolates were resistant to vancomycin, an antibiotic that has never been approved for use in livestock in the United States. In conclusion, high-level multidrug-resistant Enterococcus, coagulase-negative staphylococci, and viridans group streptococci were detected in the air of a concentrated swine feeding operation. These findings suggest that the inhalation of air from these facilities may serve as an exposure pathway for the transfer of multidrug-resistant bacterial pathogens from swine to humans

Quantum phase transitions and decoupling of magnetic sublattices in the quasi-two-dimensional Ising magnet Co3V2O8 in a transverse magnetic field

The application of a magnetic field transverse to the easy axis, Ising direction in the quasi-two-dimensional Kagome staircase magnet, Co3V2O8, induces three quantum phase transitions at low temperatures, ultimately producing a novel high field polarized state, with two distinct sublattices. New time-of-flight neutron scattering techniques, accompanied by large angular access, high magnetic field infrastructure allow the mapping of a sequence of ferromagnetic and incommensurate phases and their accompanying spin excitations. At least one of the transitions to incommensurate phases at \mu 0Hc1~6.25 T and \mu 0Hc2~7 T is discontinuous, while the final quantum critical point at \mu 0Hc3~13 T is continuous.Comment: 5 pages manuscript, 3 pages supplemental materia

Commensurate Fluctuations in the Pseudogap and Incommensurate spin-Peierls Phases of TiOCl

X-ray scattering measurements on single crystals of TiOCl reveal the presence of commensurate dimerization peaks within both the incommensurate spin-Peierls phase and the so-called pseudogap phase above T_c2. This scattering is relatively narrow in Q-space indicating long correlation lengths exceeding ~ 100 A below T* ~ 130 K. It is also slightly shifted in Q relative to that of the commensurate long range ordered state at the lowest temperatures, and it coexists with the incommensurate Bragg peaks below T_c2. The integrated scattering over both commensurate and incommensurate positions evolves continuously with decreasing temperature for all temperatures below T* ~ 130 K.Comment: To appear in Physical Review B: Rapid Communications. 5 page

Hands-on Materials for Teaching about Global Climate Change through Graph Interpretation

Teachers need to address global climate change with students in their classrooms as evidence for consequences from these environmental changes mounts. One way to approach global climate change is through examination of authentic data. Mathematics and science may be integrated by interpreting graphs from the professional literature. This study examined the types of errors 72 preservice elementary teachers made in producing hands-on materials for teaching graph interpretation skills through graphed evidence of global climate change from the literature. The teaching materials consisted of a graph electronically manipulated on a colored background and enhanced with clip art related to the graph’s topic that was then printed and mounted on colored cardboard. The graph was accompanied by six graph interpretation statements printed on cards that were to be sorted as true or false. Additionally, a topic-related object was provided for each graph for an initial activity that focused student attention and aroused interest. Four graphs with their accompanying statements and four related objects were combined into one box of materials to be used by a small group of students. Preservice teachers practiced with example sets of materials made by the course instructor and then worked to each create a new, unique set. An appendix of many sets of correct materials is provided in this ERIC document. About half of the teaching materials produced were errorfree. The most common errors preservice teachers made were misuse of vocabulary and over generalizing a graph’s information. Other frequent errors included not supplying enough specific information in a statement to allow its verification and misinterpreting a major trend on a graph. These problems can be attributed to preservice teachers’ lack of sufficient experience in graph interpretation. Therefore, the authors conclude that the materials-making exercise was beneficial to preservice teachers and the resulting materials (with any errors corrected) can effectively be used with upper elementary and secondary students. [1 Table, 1 Appendix containing 18 graphs accompanied by interpretation statements.