Advanced mission analysis programs

Computer programs provide preliminary trajectory and guidance information required for feasibility studies in space mission analysis. The advanced mission analysis computer programs include programs for approximate solutions, programs for targeting and output, and programs for Monte Carlo and linear guidance analysis

Effect of blockage ratio on drag and pressure distributions for bodies of revolution at transonic speeds

Experimental data were obtained in two wind tunnels for 13 models over a Mach number range from 0.70 to 1.02. Effects of increasing test-section blockage ratio in the transonic region near a Mach number of 1.0 included change in the shape of the drag curves, premature drag creep, delayed drag divergence, and a positive increment of pressures on the model afterbodies. Effects of wall interference were apparent in the data even for a change in blockage ratio from a very low 0.000343 to an even lower 0.000170. Therefore, models having values of blockage ratio of 0.0003 - an order of magnitude below the previously considered safe value of 0.0050 - had significant errors in the drag-coefficient values obtained at speeds near a Mach number of 1.0. Furthermore, the flow relief afforded by slots or perforations in test-section walls - designed according to previously accepted criteria for interference-free subsonic flow - does not appear to be sufficient to avoid significant interference of the walls with the model flow field for Mach numbers very close to 1.0

Advances in Moire interferometry for thermal response of composites

An experimental technique for the precise measurement of the thermal response of both sides of a laminated composite coupon specimen uses Moire interferometry with fringe multiplication which yields a sensitivity of 833 nm (32.8 micro in.) per fringe. The reference gratings used are virtual gratings and are formed by partially mirrorized glass prisms in close proximity to the specimen. Results are compared with both results obtained from tests which used Moire interferometry on one side of composite laminates, and with those predicted by classical lamination theory. The technique is shown to be capable of producing the sensitivity and accuracy necessary to measure a wide range of thermal responses and to detect small side to side variations in the measured response. Tests were conducted on four laminate configurations of T300/5208 graphite epoxy over a temperature range of 297 K (75 F) to 422 K (300 F). The technique presented allows for the generation of reference gratings for temperature regimes well outside that used in these tests

Development, validation and reliability of a questionnaire to evaluate coaches' and players' perceptions, learning, and resources regarding the ruck in rugby union

Background: The absence of a valid and reliable research tool for evaluating the attitudes, behaviours, and learning resources of rugby coaches and players concerning the ruck event presents a critical gap in the current rugby research landscape. Objectives: The objective of this study was twofold: firstly, to adapt an existing questionnaire that focussed on the tackle event, and secondly, to validate and establish the reliability of the instrument. The questionnaire is designed to explore the attitudes, behaviours, and learning resources of rugby coaches and players, with a particular emphasis on the ruck event and its potential impact on the field of rugby coach development, coaching practices, and player development. Methods: To assess content, construct, clarity, and relevance validation, a seven-step design process was followed, resulting in a high-quality questionnaire evaluated by a panel of 12 experts. Subsequently, a test-retest procedure involving 15 coaches and 16 players highlights the effectiveness of this questionnaire, emphasising its potential to generate data that can impact the field of rugby coaching and player development. Results: The validity and reliability assessment revealed that the expert panel found the questionnaire to be appropriate, and clear, and the mean time for completion was approximately 22 minutes. The ICC Agreement scores of 0.71 for players and 0.88 for coaches indicate moderate and good agreement respectively, further corroborated by narrow 95% Confidence Intervals. ICC Consistency scores (0.71 for players and 0.87 for coaches) affirmed high response consistency. In Kendall’s W scores, players achieved 0.85, while coaches reached 0.93, with significant F-statistics (p < 0.01) supporting strong agreement. Conclusion: This study introduces a methodically developed questionnaire, recognised for its clarity, reliability, and consistency. It serves as a valuable resource for future research in rugby, possessing the potential to influence coach development, coaching practices, and player development. Therefore, it makes an important contribution to the field

Medium Modifications of Hadron Properties and Partonic Processes

Chiral symmetry is one of the most fundamental symmetries in QCD. It is closely connected to hadron properties in the nuclear medium via the reduction of the quark condensate , manifesting the partial restoration of chiral symmetry. To better understand this important issue, a number of Jefferson Lab experiments over the past decade have focused on understanding properties of mesons and nucleons in the nuclear medium, often benefiting from the high polarization and luminosity of the CEBAF accelerator. In particular, a novel, accurate, polarization transfer measurement technique revealed for the first time a strong indication that the bound proton electromagnetic form factors in 4He may be modified compared to those in the vacuum. Second, the photoproduction of vector mesons on various nuclei has been measured via their decay to e+e- to study possible in-medium effects on the properties of the rho meson. In this experiment, no significant mass shift and some broadening consistent with expected collisional broadening for the rho meson has been observed, providing tight constraints on model calculations. Finally, processes involving in-medium parton propagation have been studied. The medium modifications of the quark fragmentation functions have been extracted with much higher statistical accuracy than previously possible.Comment: to appear in J. Phys.: Conf. Proc. "New Insights into the Structure of Matter: The First Decade of Science at Jefferson Lab", eds. D. Higinbotham, W. Melnitchouk, A. Thomas; added reference

Exploratory Insights into Cross-Cultural On-line Shopping Differences between U.S. and French Millennials and Generation Zs

Online retail sales have shown double-digit growth in the U.S. for the last decade lead by millennials and more recently generation Z. While extensive research has been done exploring U.S. online shopping behaviors of these generations, little cross-cultural work has been done. This paper explores the differences between the U.S. and French millennial and gen z online shoppers. The research focused on four questions; was there a difference in the number of times per week that individuals shopped online, the percentage of shopping funds spent online versus in store, the types of products purchased online, and the percentage of low priced products (below $25 or €25. Results showed significant differences between the online shopping and purchasing behaviors between French and U.S. online shoppers