Fifteen-foot diameter modular space station Kennedy Space Center launch site support definition (space station program Phase B extension definition)

This document defines the facilities, equipment, and operational plans required to support the MSS Program at KSC. Included is an analysis of KSC operations, a definition of flow plans, facility utilization and modifications, test plans and concepts, activation, and tradeoff studies. Existing GSE and facilities that have a potential utilization are identified, and new items are defined where possible. The study concludes that the existing facilities are suitable for use in the space station program without major modification from the Saturn-Apollo configuration

A cycling state that can lead to glassy dynamics in intracellular transport

Power-law dwell times have been observed for molecular motors in living cells, but the origins of these trapped states are not known. We introduce a minimal model of motors moving on a two-dimensional network of filaments, and simulations of its dynamics exhibit statistics comparable to those observed experimentally. Analysis of the model trajectories, as well as experimental particle tracking data, reveals a state in which motors cycle unproductively at junctions of three or more filaments. We formulate a master equation for these junction dynamics and show that the time required to escape from this vortex-like state can account for the power-law dwell times. We identify trends in the dynamics with the motor valency for further experimental validation. We demonstrate that these trends exist in individual trajectories of myosin II on an actin network. We discuss how cells could regulate intracellular transport and, in turn, biological function, by controlling their cytoskeletal network structures locally

Genetic integrity of the Dark European honey bee (Apis mellifera mellifera) from protected populations: a genome-wide assessment using SNPs and mtDNA sequence data

The recognition that the Dark European honey bee, Apis mellifera mellifera, is increasingly threatened in its native range has led to the establishment of conservation programmes and protected areas throughout western Europe. Previous molecular surveys showed that, despite management strategies to preserve the genetic integrity of A. m. mellifera, protected populations had a measurable component of their gene pool derived from commercial C-lineage honey bees. Here we used both sequence data from the tRNAleu-cox2 intergenic mtDNA region and a genome-wide scan, with over 1183 single nucleotide polymorphisms (SNPs), to assess genetic diversity and introgression levels in several protected populations of A. m. mellifera, which were then compared with samples collected from unprotected populations. MtDNA analysis of the protected populations revealed a single colony bearing a foreign haplotype, whereas SNPs showed varying levels of introgression ranging from virtually zero in Norway to about 14% in Denmark. Introgression overall was higher in unprotected (30%) than in protected populations (8%), and is reflected in larger SNP diversity levels of the former, although opposite diversity levels were observed for mtDNA. These results suggest that, despite controlled breeding, some protected populations still require adjustments to the management strategies to further purge foreign alleles, which can be identified by SNPs.Pint

ECCC TEST PROGRAMME AND DATA ASSESSMENT ON GTD111 CREEP RUPTURE, STRAIN AND DUCTILITY

GTD111, a creep resistant Ni-based superalloy developed by GE, is widely used in land-based gas turbine first stage blades. However, there is little published information on its creep properties and microstructure. The European Creep Collaborative Committee (ECCC) Working Group 3C consequently selected GTD111 as a model material for testing and complementary data assessment. The aim of this paper is to present the results from the ECCC test program and data assessment, and to compare equiaxed (EA) and directionally solidified (DS) material performance. Testing and metallographic laboratories from six European nations collaborated to produce strain monitored creep rupture data on four EA and DS materials out to beyond 10,000 hours within a wide range of temperatures, 850-950°C, and stresses, 293-99 MPa. Available (generally short term) results from other sources were also included in the compiled, small but viable, 51-test data set. Assessment was carried out by three different assessors using different tools and adopting different prediction models. Conventional ECCC post-assessment techniques and novel “back-fitting” methods were used to identify a preferred model. It was shown that assessing all the EA and DS data together can lead to non-conservative predictions for EA materials, but separating the two classes creates small data subsets which cannot be modelled effectively. As a pragmatic compromise, the DS data and those EA data which also showed good ductility were included in a final "ductile GTD111" assessment. The resulting creep rupture material models and rupture strength predictions are presented up to 3 times the longest test duration. It was then shown that the performance of lower ductility EA materials can also be predicted effectively with the "ductile" model by truncating the rupture time at the measured fracture strain. For this exercise, a creep strain model based on rupture and time to strain data was fitted. In parallel, microstructural examination was performed to characterize the damage modes involved in the low ductility failures. It was thereby shown that the creep rupture strength shortfall of an EA material compared to its DS equivalent is not a constant factor, but is primarily governed by the reduced creep ductility. Hence, the shortfall varies between different EA casts, and tends to become greater in the longer term.JRC.F.4-Innovative Technologies for Nuclear Reactor Safet

Modeling Stress-Dependent Anisotropic Elastoplastic Unbound Granular Base in Flexible Pavements

Unbound granular base (UGB) has a cross-anisotropic and nonlinear (stress-dependent) modulus with a plastic behavior. Existing UGB models address nonlinear cross-anisotropy and plasticity separately. It is unknown how the two characteristics are coupled into a finite element model (FEM) and how this will affect the pavement responses. This study presents a coupled nonlinear cross-anisotropic elastoplastic (NAEP) constitutive model for the UGB and implements it in a weak form equation-based FEM. No material subroutine is needed to address the circular dependence between the stress-dependent anisotropic modulus, structural stress responses, and elastoplastic deformation. The NAEP model was calibrated by triaxial resilient modulus and strength tests and validated using laboratory measurements in a large-scale soil-tank pavement structural test. It is found that the NAEP model is valid and effective in predicting the UGB responses in flexible pavements. The model predicted less horizontal tensile stresses at the base bottom and introduced compressive stresses in the middle and top of the base course. This is caused by an increasing confinement resulting from a horizontal plastic dilation in the base course, which cannot be modeled without considering plasticity. The stress-dependent modulus for the UGB material decreases with depth and the distance from loading centerline. Compared with a nonlinear anisotropic elastic model, the NAEP model predicted the same tensile strain at asphalt layer bottom, a higher base modulus, and a higher subgrade compressive strain. Thus, the nonlinear anisotropic elastic UGB model results in the same fatigue life as the NAEP model but may riskily under-predict rutting damage

The stock market reaction to losing or gaining foreign private issuer status

The U.S. Securities and Exchange Commission designates foreign-domiciled firms with securities trading in the U.S. markets as either foreign private issuers (FPIs) or domestic filers and permits exemptions from U.S. domestic securities regulation for firms that qualify as FPIs. We study the stock market reaction to foreign-domiciled firms that lose or gain FPI status for an arguably exogenous reason while maintaining their cross-listing status. After loss of FPI status, foreign firms are required to comply with U.S. domestic issuers’ continuous filing requirements, such as filing quarterly financial statements using U.S. GAAP, disclosure of insider trading, and compliance with corporate governance requirements of U.S. domestic issuers. We document a significantly positive market reaction when foreign firms lose their exemptions and must comply with regulatory requirements of U.S. domestic issuers. Further, we find that the market reacts negatively to an increase in financial statement requirements and reacts positively to fully adopting U.S. corporate governance requirements

Loss of testate amoeba functional diversity with increasing frost intensity across a continental gradient reduces microbial activity in peatlands

Soil microbial communities significantly contribute to global fluxes of nutrients and carbon. Their response to climate change, including winter warming, is expected to modify these processes through direct effects on microbial functions through osmotic stress, and changing temperature regimes. Using four European peatlands reflecting different frequencies of frost events, we show that peatland testate amoeba communities diverge among sites with different winter climates, and that this is reflected through contrasting functions. We found that exposure to harder soil frost promoted species β-diversity (species turnover) thus shifting the community composition of testate amoebae. In particular, we found that harder soil frost, and lower water-soluble phenolic compounds, induced functional turnover through the decrease of large species (-68%, > 80 μm) and the increase of small-bodied mixotrophic species (i.e. Archerella flavum; +79%). These results suggest that increased exposure to soil frost could be highly limiting for large species while smaller species are more resistant. Furthermore, we found that β-glucosidase enzymatic activity, in addition to soil temperature, strongly depended (R2 = 0.95, ANOVA) of the functional diversity of testate amoebae. Changing winter conditions can therefore strongly impact peatland decomposition process, though it remains unclear if these changes are carried–over to the growing season

Coupled-mode theory for Bose-Einstein condensates

We apply the concepts of nonlinear guided-wave optics to a Bose-Einstein condensate (BEC) trapped in an external potential. As an example, we consider a parabolic double-well potential and derive coupled-mode equations for the complex amplitudes of the BEC macroscopic collective modes. Our equations describe different regimes of the condensate dynamics, including the nonlinear Josephson effect for any separation between the wells. We demonstrate macroscopic self-trapping for both repulsive and attractive interactions, and confirm our results by numerical simulations.Comment: 4 pages, 5 figures; typos removed, figures amended; submitted to PR

Near-field interactions between metal nanoparticle surface plasmons and molecular excitons in thin-films: part I: absorption

In this and the following paper (parts I and II, respectively), we systematically study the interactions between surface plasmons of metal nanoparticles (NPs) with excitons in thin-films of organic media. In an effort to exclusively probe near-field interactions, we utilize spherical Ag NPs in a size-regime where far-field light scattering is negligibly small compared to absorption. In part I, we discuss the effect of the presence of these Ag NPs on the absorption of the embedding medium by means of experiment, numerical simulations, and analytical calculations, all shown to be in good agreement. We observe absorption enhancement in the embedding medium due to the Ag NPs with a strong dependence on the medium permittivity, the spectral position relative to the surface plasmon resonance frequency, and the thickness of the organic layer. By introducing a low index spacer layer between the NPs and the organic medium, this absorption enhancement is experimentally confirmed to be a near field effect In part II, we probe the impact of the Ag NPs on the emission of organic molecules by time-resolved and steady-state photoluminescence measurements