2,484 research outputs found

    Heat transfer on a flat plate in helium at Mach numbers 67.3 and 87.6 and in hypersonic corner flow with air at Mach number of 19

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    Hypersonic heat transfer rates on flat plates in helium and in corner flow region with ai

    Heat Transfer on a Flat Plate in Continuum to Rarefied Hypersonic Fows at Mach Numbers of 19.2 and 25.4

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    Surface heat transfer rates measured on flat plates in hypervelocity shock tunne

    Method and apparatus for monitoring oxygen partial pressure in air masks

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    Method and apparatus are disclosed for monitoring an oxygen partial pressure in an air mask and providing a tactile warning to the user. The oxygen partial pressure in the air mask is detected using an electrochemical sensor, the output signal from which is provided to a comparator. The comparator compares the output signal with a preset reference value or range of values representing acceptable oxygen partial pressures. If the output signal is different than the reference value or outside the range of values, the air mask is vibrated by a vibrating motor to alert the user to a potentially hypoxic condition

    Wetland vegetation monitoring, 1998 survey: Gnangara wetlands

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    Water regimes, both groundwater and surface water components dil\u27ectly effect distribution, health and species composition of wetland fringing vegetation. In the area of the northern Swan Coastal Plain overlying the Gnangara groundwater mound, wetland water levels and therefore the vegetation can be intimately connected to underlying groundwater levels. The Water Corporation (formerly Water Authority of Western Australia) has been drawing water from the Gnangara mound for domestic water supply for a number of years. The main objective of this study is to monitor the changes in the vegetation fringing these wetlands and to determine if this is related to changes in groundwater or other factors affecting the lakes. Wetlands of specific interest in 1998, because of breached guidelines for groundwater drawdown through abstraction, have been summarized in detail in this report. These wetlands include Lakes Joondalup, Jandabup, Mariginup and Nowergup. Raw data from the 1998 survey for the other wetlands monitored in 1997, as well as the wetlands mentioned above, are presented in Appendix 1..

    Meltwater Intrusions Reveal Mechanisms for Rapid Submarine Melt at a Tidewater Glacier

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    Submarine melting has been implicated as a driver of glacier retreat and sea level rise, but to date melting has been difficult to observe and quantify. As a result, melt rates have been estimated from parameterizations that are largely unconstrained by observations, particularly at the near-vertical termini of tidewater glaciers. With standard coefficients, these melt parameterizations predict that ambient melting (the melt away from subglacial discharge outlets) is negligible compared to discharge-driven melting for typical tidewater glaciers. Here, we present new data from LeConte Glacier, Alaska, that challenges this paradigm. Using autonomous kayaks, we observe ambient meltwater intrusions that are ubiquitous within 400 m of the terminus, and we provide the first characterization of their properties, structure, and distribution. Our results suggest that ambient melt rates are substantially higher (×100) than standard theory predicts and that ambient melting is a significant part of the total submarine melt flux. We explore modifications to the prevalent melt parameterization to provide a path forward for improved modeling of ocean-glacier interactions.This work was funded by NSF OPP Grants 1503910, 1504191, 1504288, and 1504521 and National Geographic Grant CP4-171R-17. Additionally, this research was supported by the NOAA Climate and Global Change Postdoctoral Fellowship Program, administered by UCAR’s Cooperative Programs for the Advancement of Earth System Science (CPAESS) under award #NA18NWS4620043B. These observations would not be possible without the skilled engineering team who developed the autonomous kayaks—including Jasmine Nahorniak, June Marion, Nick McComb, Anthony Grana, and Corwin Perren—and also the Captain and crew of the M/V Amber Anne. We thank Donald Slater and an anonymous reviewer for valuable feedback that improved this manuscript. Data availability: All of the oceanographic data collected by ship and kayak have been archived with the National Centers for Environmental Information (Accession 0189574, https://accession.nodc.noaa.gov/ 0189574). The glacier data have been archived at the Arctic Data Center (https://doi.org/10.18739/A22G44).Ye

    Emergence: Key physical issues for deeper philosophical inquiries

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    A sketch of three senses of emergence and a suggestive view on the emergence of time and the direction of time is presented. After trying to identify which issues philosophers interested in emergent phenomena in physics view as important I make several observations pertaining to the concepts, methodology and mechanisms required to understand emergence and describe a platform for its investigation. I then identify some key physical issues which I feel need be better appreciated by the philosophers in this pursuit. I end with some comments on one of these issues, that of coarse-graining and persistent structures.Comment: 16 pages. Invited Talk at the Heinz von Foerster Centenary International Conference on Self-Organization and Emergence: Emergent Quantum Mechanics (EmerQuM11). Nov. 10-13, 2011, Vienna, Austria. Proceedings to appear in J. Phys. (Conf. Series

    The Right Wrong‐Makers

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    Right- and wrong-making features ("moral grounds") are widely believed to play important normative roles, e.g. in morally apt or virtuous motivation. This paper argues that moral grounds have been systematically misidentified. Canonical statements of our moral theories tend to summarize, rather than directly state, the full range of moral grounds posited by the theory. Further work is required to "unpack" a theory's criterion of rightness and identify the features that are of ground-level moral significance. As a result, it is not actually true that maximizing value is the relevant right-making feature even for maximizing consequentialists. Focusing on the simple example of utilitarianism, I show how careful attention to the ground level can drastically influence how we think about our moral theories

    Emergence: Key physical issues for deeper philosophical inquiries

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    A sketch of three senses of emergence and a suggestive view on the emergence of time and the direction of time is presented. After trying to identify which issues philosophers interested in emergent phenomena in physics view as important I make several observations pertaining to the concepts, methodology and mechanisms required to understand emergence and describe a platform for its investigation. I then identify some key physical issues which I feel need be better appreciated by the philosophers in this pursuit. I end with some comments on one of these issues, that of coarse-graining and persistent structures.Comment: 16 pages. Invited Talk at the Heinz von Foerster Centenary International Conference on Self-Organization and Emergence: Emergent Quantum Mechanics (EmerQuM11). Nov. 10-13, 2011, Vienna, Austria. Proceedings to appear in J. Phys. (Conf. Series

    Flight Readiness of Mochii S: Portable Spectroscopic Scanning Electron Microscope Facility on the International Space Station (ISS)

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    The ISS (International Space Station) currently lacks the capability to image and chemically analyze nano-to-micron scale particles from numerous engineering systems. To identify these particles, we must wait for a re-entry vehicle to return them from low earth orbit for ground-based SEM (Scanning Electron Microscope) / EDS (Energy Dispersive X-Ray Spectroscopy) analysis. This may take months, potentially delaying the affected system. Having an EDS-equipped SEM (Mochii S) aboard the ISS will accelerate response time thereby enhancing crew and vehicle safety by rapid and accurate identification of microscopic threats, especially in time-critical situations.The Mochii S payload will be stationed in the Japanese Experiment Module (JEM) powered by 120 VAC (Volts Alternating Current) inverter and connected to station Ethernet and WiFi (Fig. 1). To date the Mochii S payload has undergone testing for command and data handling, power quality, flight vibration, and radiation testing at Johnson Space Center (JSC). Mochii's high-RPM (Revolutions Per Minute) rotating vacuum pumps and high voltage systems have been reviewed to meet safety standards by JSC (Johnson Space Center) Engineering. Topology of the system in the JEM module has been baselined by ISS Safety and JAXA (Japan Space Exploration Agency). Digital controls to and from ISS over Joint Station LAN (Local Area Network) uplink have been simulated and the latencies and data rates have been found to be sufficient for successful operation of the payload from ground.Transporting sensitive electron optical instruments aboard a rocket that sustains 7G acceleration for 8 minutes and then operating it the unique microgravity (micro-g) environment is no trivial matter. To meet strict safety requirements and increase robustness for mission success, over 500 unique verifications must be completed before the payload is certified for spaceflight. Two of which will be discussed in detail are: vibroacoustic testing and magnetic susceptibility shielding and validation
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