3,384 research outputs found
Ultrafast spherulitic crystal growth as a stress-induced phenomenon specific of fragile glass-formers
We propose a model for the abrupt emergence, below temperatures close to the
glass transition, of the ultra-fast (GC) steady mode of spherulitic crystal
growth in deeply undercooled liquids. We interpret this phenomenon as
controlled by the interplay between the generation of stresses by
crystallization and their partial release by flow in the surrounding amorphous
visco-elastic matrix. Our model is consistent with both the observed ratios
() of fast-to-slow velocities and the fact that fast growth emerges
close to the glass transition. It leads us to conclude that the existence of a
fast growth regime requires both (i) a high fragility of the glassformer; (ii)
the fine sub-structure specific of spherulites. It finally predicts that the
transition is hysteretic, thus allowing for an independent experimental test
Independent Orbiter Assessment (IOA): Assessment of the mechanical actuation subsystem, volume 2
The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA approach features a top-down analysis of the hardware to determine draft failure modes, criticality, and potential critical items. To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. The IOA results were then compared to the proposed Post 51-L NASA FMEA/CIL baseline that was available. A resolution of each discrepancy from the comparison was provided through additional analysis as required. These discrepancies were flagged as issues, and recommendations were made based on the FMEA data available at the time. This report documents the results of that comparison for the Orbiter Mechanical Actuation System (MAS) hardware. Specifically, the MAS hardware consists of the following components: Air Data Probe (ADP); Elevon Seal Panel (ESP); External Tank Umbilical (ETU); Ku-Band Deploy (KBD); Payload Bay Doors (PBD); Payload Bay Radiators (PBR); Personnel Hatches (PH); Vent Door Mechanism (VDM); and Startracker Door Mechanism (SDM). Criticality was assigned based upon the severity of the effect for each failure mode. Volume 2 continues the presentation of IOA analysis worksheets and contains the potential critical items list, detailed analysis, and NASA FMEA/CIL to IOA worksheet cross reference and recommendations
Preliminary Results on the Structure and Functioning of a Taiga Watershed
Comprehensive research in ecosystem functioning may logically be
undertaken in the conceptual and physical context of complete drainage
basins (watersheds or catchments). The watershed forms a fundamental,
cohesive landscape unit in terms of water movement following initial
receipt of precipitation. Water itself is a fundamental agent in energy
flux, nutrient transport, and in plant and animal life. The Caribou-Poker
Creeks Research Watershed is an interagency endeavor aimed at
understanding hydrologic and, ultimately, ecological functioning in the
subarctic taiga, the discontinuous permafrost uplands of central Alaska.
Initial work includes acquisition and analysis of data on soils, vegetation,
local climate, hydrology, and stream quality. Information
acquired in the research watershed is summarized here, and implications
for future data acquisition and research are considered
International Rent Sharing in Multinational Firms
We use a unique firm-level panel data set of multinational parents and their foreign affiliates to analyze whether profits are shared across borders within multinational firms. Using both fixed-effects and generalized method-of-moments estimators, affiliate wage levels are estimated to respond to both and parent profitability. The elasticity of affiliate wages to parent profits per worker is approximately 0.03, which can explain over 20 percent of the observed variation in affiliate wages. These results reveal a previously ignored aspect of labor market rent sharing. They also reveal an important micro-level linkage with potential macro-level implications. International rent sharing can transmit economic conditions across national borders, and can thereby provide an implicit cross-country risk-sharing mechanism.
ON EUCLIDEAN NETWORKS FOR IMPROVING CLASSIFICATION ACCURACY
Machine learning is found in nearly every facet of daily life. Large amounts of data are required but not always available for specific problems, precluding the use of advanced methods such as deep learning and convolutional neural networks. The Euclidean Network (EN) can be used to mitigate these issues. The EN was thoroughly tested to prove its viability as a classification algorithm and that its methods may be used to augment data and transform the input data to increase its feature space dimensionality. Originally, it was hypothesized that the EN could be used to synthetically generate data to augment a data set, though this method was proven to be ineffective. The next area of research sought to expand the dimensionality of the input feature space to improve performance with additional classifiers. This area showed positive results, which supported the hypothesis that more complex, dense input would give algorithms more insight into the data and improve performance. The EN has been found to perform exceptionally well as an independent classifier, as it achieved the highest accuracy for 12 of the 21 data sets. For the remaining 9, though it did not have the highest accuracy, the EN performed comparably to more sophisticated algorithms. The EN also proved capable to expand a data set's feature space to further improve performance. This tactic provided a more robust classification technique and saw an average increase in accuracy of 3% between all data sets.Captain, United States Marine CorpsApproved for public release. Distribution is unlimited
Wages and International Rent Sharing in Multinational Firms
We use a unique firm-level panel data set of multinational parents and their foreign affiliates to analyze whether profits are shared across borders within multinational firms. Using both fixed-effects and generalized method-of-moments estimators, affiliate wage levels are estimated to respond to both affiliate and parent profitability. The elasticity of affiliate wages to parent profits per worker is approximately 0.03, which can explain over 20 percent of the observed variation in affiliate wages. These results reveal a previously ignored aspect of labor-market rent sharing. They also reveal an important micro-level linkage with potential macro-level implications. International rent sharing can transmit economic conditions across national borders, and can thereby provide an implicit cross-country risk-sharing mechanism.Wages, Profit Sharing, Multinational Firms
International Rent Sharing in Multinational Firms
We use a unique firm-level panel data set of multinational parents and their foreign affiliates to analyze whether profits are shared across borders within multinational firms. Using both fixed-effects and generalized method-of-moments estimators, affiliate wage levels are estimated to respond to both affiliate and parent profitability. The elasticity of affiliate wages to parent profits per worker is approximately 0.03, which can explain over 20 percent of the observed variation in affiliate wages. These results reveal a previously ignored aspect of labor-market rent sharing. They also reveal an important micro-level linkage with potential macro-level implications. International rent sharing can transmit economic conditions across national borders, and can thereby provide an implicit cross-country risk-sharing mechanism.
Small quantity production of complex chromium alloy sheet /Cr-7Mo-2Ta-0.09C-0.1Y/ Final report
Fabrication of Cr-Mo-Ta-C-Y alloy shee
- …