Investigation of Ceramic, Graphite, and Chrome-plated Graphite Nozzles on Rocket Engine

The use of ceramic material for rocket nozzles and the effectiveness of preventing oxidation and erosion of graphite nozzles by chrome-plating the internal surface were investigated. A supported ceramic nozzle, cracked by initial operation, was operated a second time without further cracking or damage. Chrome-plating the internal surface of graphite nozzles effectively prevented oxidation and erosion that occurred during operation with unprotected graphite

Internal-liquid-film-cooling Experiments with Air-stream Temperatures to 2000 Degrees F. in 2- and 4-inch-diameter Horizontal Tubes

Report presents the results of an investigation conducted to determine the effectiveness of liquid-cooling films on the inner surfaces of tubes containing flowing hot air. Experiments were made in 2- and 4-inch-diameter straight metal tubes with air flows at temperatures from 600 degrees to 2000 degrees F. and diameter Reynolds numbers from 2.2 to 14 x 10(5). The film coolant, water, was injected around the circumference at a single axial position on the tubes at flow rates from 0.02 to .24 pound per second per foot of tube circumference (0.8 to 12 percent of the air flow). Liquid-coolant films were established and maintained around and along the tube wall in concurrent flow with the hot air. The results indicated that, in order to film cool a given surface area with as little coolant flow as possible, it may be necessary to limit the flow of coolant introduced at a single axial position and to introduce it at several axial positions. The flow rate of inert coolant required to maintain liquid-film cooling over a given area of tube surface can be estimated when the gas-flow conditions are known by means of a generalized plot of the film-cooling data

From pre-implementation to institutionalization: Lessons from sustaining a perinatal audit program in South Africa

Maternal and perinatal death surveillance and response (MPDSR), or related forms of maternal and perinatal death audits, can strengthen health systems. We explore the history of initiating, scaling up, and institutionalizing a national perinatal audit program in South Africa. : Data collection involved 56 individual interviews, a systematic document review, administration of a semistructured questionnaire, and 10 nonparticipant observations of meetings related to the perinatal audit program. Fieldwork and data collection in the subdistricts occurred from September 2019 to March 2020. Data analysis included thematic content analysis and application of a tool to measure subdistrict-level implementation. This study expands on case study research applied to 5 Western Cape subdistricts with long histories of implementation

Overview of the NASA Entry, Descent and Landing Systems Analysis Study

NASA senior management commissioned the Entry, Descent and Landing Systems Analysis (EDL-SA) Study in 2008 to identify and roadmap the Entry, Descent and Landing (EDL) technology investments that the agency needed to make in order to successfully land large payloads at Mars for both robotic and human-scale missions. This paper summarizes the approach and top-level results from Year 1 of the Study, which focused on landing 10-50 mt on Mars, but also included a trade study of the best advanced parachute design for increasing the landed payloads within the EDL architecture of the Mars Science Laboratory (MSL) mission

From pre-implementation to institutionalization : lessons From sustaining a perinatal audit program in South Africa

DATA AVAILABILITY STATEMENTS : All data relevant to the study are included in the article or uploaded as supplemental information. Patient identifiable data not applicable.INTRODUCTION : Maternal and perinatal death surveillance and response (MPDSR), or related forms of maternal and perinatal death audits, can strengthen health systems. We explore the history of initiating, scaling up, and institutionalizing a national perinatal audit program in South Africa. METHODS : Data collection involved 56 individual interviews, a systematic document review, administration of a semistructured questionnaire, and 10 nonparticipant observations of meetings related to the perinatal audit program. Fieldwork and data collection in the subdistricts occurred from September 2019 to March 2020. Data analysis included thematic content analysis and application of a tool to measure subdistrict-level implementation. This study expands on case study research applied to 5 Western Cape subdistricts with long histories of implementation. RESULTS : Although established in the early 1990s, the perinatal audit program was not integrated into national policy and guidelines until 2012 but was then excluded from policy in 2021. A network of national and subnational structures that benefited from a continuity of actors evolved and interacted to support uptake and implementation. Intentional efforts to demonstrate impact and enable local adaptation allowed for more ownership and buy-in. Implementation requires continuous efforts. Even in 5 subdistricts with long histories of practice, we found operational gaps, such as incomplete meeting minutes, signaling a need for strengthening. Nevertheless, the tool used to measure implementation may require revisions, particularly in settings with institutionalized practice. CONCLUSION : This article provides lessons on how to initiate, expand, and strengthen perinatal audit. Despite a long history of implementation, the perinatal audit program in South Africa cannot be assumed to be indefinitely sustainable or final in its current form. To monitor uptake and sustainability of MPDSR, including perinatal audit, we need research approaches that allow exploration of context, local adaptation, and underlying issues that support sustainability, such as relationships, leadership, and trust.The South African Research Chair’s Initiative of the Department of Science and Technology, National Research Foundation of South Africa, the South African Medical Research Council, and the Countdown 2030 project funded by the Bill & Melinda Gates Foundation.http://www.ghspjournal.orgObstetrics and GynaecologySDG-03:Good heatlh and well-bein

Ecological characteristics of core-use areas used by Bering–Chukchi–Beaufort (BCB) bowhead whales, 2006–2012

© The Author(s), 2014]. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Progress in Oceanography 136 (2015): 201-222, doi:10.1016/j.pocean.2014.08.012.The Bering–Chukchi–Beaufort (BCB) population of bowhead whales (Balaena mysticetus) ranges across the seasonally ice-covered waters of the Bering, Chukchi, and Beaufort seas. We used locations from 54 bowhead whales, obtained by satellite telemetry between 2006 and 2012, to define areas of concentrated use, termed “core-use areas”. We identified six primary core-use areas and describe the timing of use and physical characteristics (oceanography, sea ice, and winds) associated with these areas. In spring, most whales migrated from wintering grounds in the Bering Sea to the Cape Bathurst polynya, Canada (Area 1), and spent the most time in the vicinity of the halocline at depths <75 m, which are within the euphotic zone, where calanoid copepods ascend following winter diapause. Peak use of the polynya occurred between 7 May and 5 July; whales generally left in July, when copepods are expected to descend to deeper depths. Between 12 July and 25 September, most tagged whales were located in shallow shelf waters adjacent to the Tuktoyaktuk Peninsula, Canada (Area 2), where wind-driven upwelling promotes the concentration of calanoid copepods. Between 22 August and 2 November, whales also congregated near Point Barrow, Alaska (Area 3), where east winds promote upwelling that moves zooplankton onto the Beaufort shelf, and subsequent relaxation of these winds promoted zooplankton aggregations. Between 27 October and 8 January, whales congregated along the northern shore of Chukotka, Russia (Area 4), where zooplankton likely concentrated along a coastal front between the southeastward-flowing Siberian Coastal Current and northward-flowing Bering Sea waters. The two remaining core-use areas occurred in the Bering Sea: Anadyr Strait (Area 5), where peak use occurred between 29 November and 20 April, and the Gulf of Anadyr (Area 6), where peak use occurred between 4 December and 1 April; both areas exhibited highly fractured sea ice. Whales near the Gulf of Anadyr spent almost half of their time at depths between 75 and 100 m, usually near the seafloor, where a subsurface front between cold Anadyr Water and warmer Bering Shelf Water presumably aggregates zooplankton. The amount of time whales spent near the seafloor in the Gulf of Anadyr, where copepods (in diapause) and, possibly, euphausiids are expected to aggregate provides strong evidence that bowhead whales are feeding in winter. The timing of bowhead spring migration corresponds with when zooplankton are expected to begin their spring ascent in April. The core-use areas we identified are also generally known from other studies to have high densities of whales and we are confident these areas represent the majority of important feeding areas during the study (2006–2012). Other feeding areas, that we did not detect, likely existed during the study and we expect core-use area boundaries to shift in response to changing hydrographic conditions.This study is part of the Synthesis of Arctic Research (SOAR) and was funded in part by the U.S. Department of the Interior, Bureau of Ocean Energy Management, Environmental Studies Program through Interagency Agreement No. M11PG00034 with the U.S. Department of Commerce, National Oceanic and Atmospheric Administration (NOAA), Office of Oceanic and Atmospheric Research (OAR), Pacific Marine Environmental Laboratory (PMEL). Funding for this research was mainly provided by U.S. Minerals Management Service (now Bureau of Ocean Energy Management) under contracts M12PC00005, M10PS00192, and 01-05-CT39268, with the support and assistance from Charles Monnett and Jeffery Denton, and under Interagency Agreement No. M08PG20021 with NOAA-NMFS and Contract No. M10PC00085 with ADF&G. Work in Canada was also funded by the Fisheries Joint Management Committee, Ecosystem Research Initiative (DFO), and Panel for Energy Research and Development

Bronchoarterial ratio in never‐smokers adults: Implications for bronchial dilation definition

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135610/1/resp12875_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/135610/2/resp12875.pd

Sloan Digital Sky Survey Imaging of Low Galactic Latitude Fields: Technical Summary and Data Release

The Sloan Digital Sky Survey (SDSS) mosaic camera and telescope have obtained five-band optical-wavelength imaging near the Galactic plane outside of the nominal survey boundaries. These additional data were obtained during commissioning and subsequent testing of the SDSS observing system, and they provide unique wide-area imaging data in regions of high obscuration and star formation, including numerous young stellar objects, Herbig-Haro objects and young star clusters. Because these data are outside the Survey regions in the Galactic caps, they are not part of the standard SDSS data releases. This paper presents imaging data for 832 square degrees of sky (including repeats), in the star-forming regions of Orion, Taurus, and Cygnus. About 470 square degrees are now released to the public, with the remainder to follow at the time of SDSS Data Release 4. The public data in Orion include the star-forming region NGC 2068/NGC 2071/HH24 and a large part of Barnard's loop.Comment: 31 pages, 9 figures (3 missing to save space), accepted by AJ, in press, see http://photo.astro.princeton.edu/oriondatarelease for data and paper with all figure