2,226 research outputs found
Interplanetary Electric Propulsion Uranus Mission Trades Supporting the Decadal Survey
The Decadal Survey Committee was tasked to develop a comprehensive science and mission strategy for planetary science that updates and extends the National Academies Space Studies Board s current solar system exploration decadal survey. A Uranus orbiter mission has been evaluated as a part of this 2013-2022 Planetary Science Decadal Survey. A comprehensive Uranus orbiter mission design was completed, including a broad search of interplanetary electric propulsion transfer options. The scope of interplanetary trades was limited to electric propulsion concepts, both solar and radioisotope powered. Solar electric propulsion offers significant payloads to Uranus. Inserted mass into the initial science orbit due is highly sensitive to transfer time due to arrival velocities. The recommended baseline trajectory is a 13 year transfer with an Atlas 551, a 1+1 NEXT stage with 15 kW of power using an EEJU trajectory and a 1,000km EGA flyby altitude constraint. This baseline delivers over 2,000kg into the initial science orbit. Interplanetary trajectory trades and sensitivity analyses are presented herein
Internal Markets for Supply Chain Capacity Allocation
This paper explores the possibility of solving supply chain capacity allocation problems using internal markets among employees of the same company. Unlike earlier forms of transfer pricing, IT now makes it easier for such markets to involve many employees, finegrained transactions, and frequently varying prices. The paper develops a formal model of such markets, proves their optimality in a baseline condition, and then analyzes various potential market problems and solutions. Interestingly, these proposed solutions are not possible in a conventional market because they rely on the firm's ability to pay market participants based on factors other than just the profitability of their market transactions. For example, internal monopolies can be ameliorated by paying internal monopolists on the basis of corporate, not individual, profits. Incentives for collusion among peers can be reduced by paying participants based on their profits relative to peers. Profit-reducing competition among different sales channels can be reduced by imposing an internal sales tax. And problems caused by fixed costs can be avoided by combining conditional internal markets with a pivot mechanism
The tensile elastic properties at low temperatures of 18:8 Cr-Ni steel as affected by heat treatment and slight plastic deformation
The Effects of Pre- and Post-Exercise Whey vs. Casein Protein Consumption on Body Composition and Performance Measures in Collegiate Female Athletes
Two of the most popular forms of protein on the market are whey and casein. Both proteins are derived from milk however the two differ concerning their absorption in the body. This difference between whey and casein proteins could affect the response seen in conjunction with training. PURPOSE: To investigate the potential effects of two types of protein ingestion in conjunction with a controlled resistance training program utilizing college female basketball players. METHODS: 16 NCAA Division III female basketball players were matched according to weight and double-blind randomly assigned to consume 24 grams whey protein (WP) (N = 8, 20 ± 1.9 years, 158 ± 27.3 cm, 66 ± 4.9 kg, 27 ± 4.9 %BF) or 24 grams casein protein (CP) (N = 8, 21 ± 2.8 years, 153 ± 2.9 cm, 68 ± 2.9 kg, 25 ± 5.7 %BF) pre- and post-exercise for eight weeks. Subjects participated in a supervised 4-day per week undulating periodized training program. At 0, 4, and 8 weeks, subjects underwent DEXA body composition analysis. At 0 and 8 weeks subjects underwent 1RM strength, muscle endurance, vertical jump, 5-10-5 and broad jump testing sessions. Data analysis using repeated measures ANOVA are presented as mean ± SD changes from baseline after 60 days. RESULTS: No significant group x time interaction effects were observed among groups in changes in any variable (p \u3e 0.05). A significant time effect was observed for body fat (WP: -2 ± 1.1 %BF; CP: -1 ± 1.6 %BF, p \u3c 0.001), lean mass (WP: 1.5 ± 1 kg; CP: 1.4 ± 1 kg, p \u3c 0.001), fat mass (WP: -1.3 ± 1.2 kg; CP: -0.6 ± 1.4 kg, p \u3c 0.001), leg press 1RM (WP: 88.7 ± 43.9 kg; CP: 90 ± 48.5 kg, p \u3c 0.001), bench press 1RM (WP: 7.5 ± 4.6 kg; CP: 4.3 ±4.5 kg, p = 0.01), vertical jump (WP: 1.6 ± 0.74 in; CP: 1.4 ± 3 in, p \u3c 0.001), 5-10-5 (WP: -0.3 ± 0.2 sec; CP: -0.09 ± 0.42 sec, p \u3c 0.001), and broad jump (WP: 4.1 ± 2.6 in; CP: 5.1 ± 2.8 in, p \u3c 0.001). CONCLUSION: The combination of a controlled undulating resistance training program with pre- and post-exercise protein supplementation is capable of inducing significant changes in performance and body composition. There does not appear to be a difference in the performance enhancing effects of whey versus casein proteins
The Pleistocene geoarchaeology and geochronology of Con Moong Cave, North Vietnam: Site formation processes and hominin activity in the humid tropics
This paper presents the results of geoarchaeological and geochronological investigations at Con Moong Cave, North Vietnam. Beneath the published, terminal Pleistocene sequence, recent excavations have uncovered a ~5 m stratigraphic sequence containing flaked stone artifacts and sedimentary features that indicate extensive post-depositional change. As the effects of tropical conditions on Pleistocene cave sediments are poorly resolved, a range of complementary techniques was selected to reconstruct the nature of on-site sedimentation and occupation, while assessing the taphonomy of archaeological and palaeoecological materials. Our approach incorporates microstratigraphic, geochemical and sedimentological analyses, using optically stimulated luminescence (OSL) dating to estimate the time of sediment deposition in the cave. This case study has broad application to tropical zones worldwide. Sedimentation began in early Marine Isotope Stage (MIS) 4, while micromorphologically observed human occupation commenced before 42 thousand years ago (ka). By placing our results within the context of published, high-resolution regional records of climate, we demonstrate that on-site rhythms of Pleistocene occupation correlated with environmental changes in the region. During MIS 3, episodic abandonment of the site coincided with periods of drier conditions, while rapid climate fluctuations in MIS 2 corresponded with short-lived occupation events and a switch to predominantly geogenic deposition in the cave
What determines auditory similarity? The effect of stimulus group and methodology.
Two experiments on the internal representation of auditory stimuli compared the pairwise and grouping methodologies as means of deriving similarity judgements. A total of 45 undergraduate students participated in each experiment, judging the similarity of short auditory stimuli, using one of the methodologies. The experiments support and extend Bonebright's (1996) findings, using a further 60 stimuli. Results from both methodologies highlight the importance of category information and acoustic features, such as root mean square (RMS) power and pitch, in similarity judgements. Results showed that the grouping task is a viable alternative to the pairwise task with N > 20 sounds whilst highlighting subtle differences, such as cluster tightness, between the different task results. The grouping task is more likely to yield category information as underlying similarity judgements
Transitions Induced by the Discreteness of Molecules in a Small Autocatalytic System
Autocatalytic reaction system with a small number of molecules is studied
numerically by stochastic particle simulations. A novel state due to
fluctuation and discreteness in molecular numbers is found, characterized as
extinction of molecule species alternately in the autocatalytic reaction loop.
Phase transition to this state with the change of the system size and flow is
studied, while a single-molecule switch of the molecule distributions is
reported. Relevance of the results to intracellular processes are briefly
discussed.Comment: 5 pages, 4 figure
Acute glycemic and blood lipid response to the ingestion of a candy bar-like protein supplement compared to its candy bar counterpart
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