Advanced rocket engine cryogenic turbopump bearing thermal model

A lumped node thermal model was developed representing the Space Shuttle Main Engine (SSME) liquid oxygen (LOX) turbopump turbine end bearings operating in a cryogenically cooled bearing tester. Bearing elements, shaft, carrier, housing, cryogen flow characteristics, friction heat, and fluid viscous energy are included in the model. Heat transfer characteristics for the regimes of forced convection boiling are modeled for liquid oxygen (LOX) and liquid nitrogen (LN2). Large temperature differences between the cryogenic fluid and baring contact surfaces require detailed nodal representation in these areas. Internal loads and friction heat are affected by temperature dependent operating clearances requiring iterations between bearing thermal and mechanical models. Analyses indicate a thermal-mechanical coupling resulting in reduced operating clearances, increased loading and heating which can contribute to premature bearing failure. Contact surfaces operate at temperatures above local saturation resulting in vapor rather than liquid in the contacts, precluding possible liquid film lubrication. Elevated temperatures can reduce lubrication, increase friction, and reduce surface hardness supporting a surface failure mode rather than subsurface fatigue

Rural Low-income Families Speak: Living in Rural Louisiana (Research Information Sheet # 109)

After the passage of federal welfare reform legislation in 1996, faculty from land-grant universities organized to conduct a study of the legislation’s impact on rural families. The project began in 1998 and runs through 2008. The intent was to provide policymakers and program directors with up-to-date information about the ability of rural, low-income families to be economically self sufficient. The objectives of this project are included in this publication.https://digitalcommons.lsu.edu/agcenter_researchinfosheets/1000/thumbnail.jp

Probing the dynamics of quasicrystal growth using synchrotron live imaging

The dynamics of quasicrystal growth remains an unsolved problem in condensed matter. By means of synchrotron live imaging, facetted growth proceeding by the tangential motion of ledges at the solid-melt interface is clearly evidenced all along the solidification of icosahedral AlPdMn quasicrystals. The effect of interface kinetics is significant so that nucleation and free growth of new facetted grains occur in the melt when the solidification rate is increased. The evolution of these grains is explained in details, which reveals the crucial role of aluminum rejection, both in the poisoning of grain growth and driving fluid flow

Quantitative assessment of chronic lung disease of infancy using computed tomography

The aims of this study were to determine whether infants and toddlers with chronic lung disease of infancy (CLDI) have smaller airways and lower lung density compared with full-term healthy controls. Multi-slice computed tomography (CT) chest scans were obtained at elevated lung volumes during a brief respiratory pause in sedated infants and toddlers;38 CLDI were compared with 39 full-term controls. For CLDI subjects, gestational age at birth ranged from 25 to 29 weeks. Airway size was measured for the trachea and the next three to four generations into the right lower lobe;lung volumes and tissue density were also measured. The relationship between airway size and airway generation differed between the CLDI and full-term groups;the sizes of the first and second airway generations were larger in the shorter CLDI than in the shorter full-term subjects. The increased size in the airways in the CLDI subjects was associated with increasing mechanical ventilation time in the neonatal period. CLDI subjects had a greater heterogeneity of lung density compared with full-term subjects. Our results indicate that quantitative analysis of multi-slice CT scans at elevated volumes provides important insights into the pulmonary pathology of infants and toddlers with CLDI

Additive manufacturing (AM) capacitive acoustic and ultrasonic transducers using a commercial direct light processing (DLP) printer

In recent years, there has been increasing interest in using additive manufacturing (3D printing) technology to fabricate sensors and actuators due to rapid prototyping, low-cost manufacturing processes, customized features and the ability to create complex geometries at micrometre scale. State of the art additive manufactured acoustic and ultrasonic transducers show limitations in miniaturization, repeatability (defects) and sensitivity. This new work encompasses the development of a capacitive acoustic and ultrasonic transducer, including its fabrication process using a commercial digital light processing printer and output signal characterization with a custom-made amplification circuit. A set of capacitive acoustic and ultrasonic transducers was fabricated and tested using different diaphragm diameters from 1.8 -2.2mm, for comparison, with central operating frequency between 19 -54 kHz, respectively. This capacitive transducer design has a receiving sensitivity of up to 0.4 mV/Pα at its resonant frequency, and a comparison with a commercial reference microphone is provided

Accumulation of Self-Reactive Naive and Memory B Cell Reveals Sequential Defects in B Cell Tolerance Checkpoints in Sjogren's Syndrome

This work was funded by grants number 18237 and 20089 from Arthritis Research UK (http://www.arthritisresearchuk.org) to MB and the William Harvey Research Foundation. EC was recipient of short-term travel fellowships from EMBO (ASTF 318-2010) and EFIS-IL

‘Sell[ing] what hasn’t got a name’: An exploration of the different understandings and definitions of ‘community engagement’ work in the performing arts

Widely known to promote broader involvement in the processes which define the arts and culture (Webster, 1997), community engagement work in the performing arts — despite employing a set of commonly recognised norms — has tended to be conceptualised differently both historically and contemporarily. Drawing on ethnographic research — particularly semi-structured qualitative interview accounts of numerous British practitioners with a track record of work in the sector, the article explores these different conceptualisations. The article finds that it is the actual ‘work that matters’ and not what it is named, and that the diversity of understandings and definitions among sectoral practitioners is reflective of evolving thinking, values and practice, something that may be destabilising for better or worse

Eutectic Colony Formation: A Stability Analysis

Experiments have widely shown that a steady-state lamellar eutectic solidification front is destabilized on a scale much larger than the lamellar spacing by the rejection of a dilute ternary impurity and forms two-phase cells commonly referred to as `eutectic colonies'. We extend the stability analysis of Datye and Langer for a binary eutectic to include the effect of a ternary impurity. We find that the expressions for the critical onset velocity and morphological instability wavelength are analogous to those for the classic Mullins-Sekerka instability of a monophase planar interface, albeit with an effective surface tension that depends on the geometry of the lamellar interface and, non-trivially, on interlamellar diffusion. A qualitatively new aspect of this instability is the occurence of oscillatory modes due to the interplay between the destabilizing effect of the ternary impurity and the dynamical feedback of the local change in lamellar spacing on the front motion. In a transient regime, these modes lead to the formation of large scale oscillatory microstructures for which there is recent experimental evidence in a transparent organic system. Moreover, it is shown that the eutectic front dynamics on a scale larger than the lamellar spacing can be formulated as an effective monophase interface free boundary problem with a modified Gibbs-Thomson condition that is coupled to a slow evolution equation for the lamellar spacing. This formulation provides additional physical insights into the nature of the instability and a simple means to calculate an approximate stability spectrum. Finally, we investigate the influence of the ternary impurity on a short wavelength oscillatory instability that is already present at off-eutectic compositions in binary eutectics.Comment: 26 pages RevTex, 14 figures (28 EPS files); some minor changes; references adde

Combined population genomic screening for three high-risk conditions in Australia: a modelling study

BACKGROUND: No previous health-economic evaluation has assessed the impact and cost-effectiveness of offering combined adult population genomic screening for mutliple high-risk conditions in a national public healthcare system. METHODS: This modeling study assessed the impact of offering combined genomic screening for hereditary breast and ovarian cancer, Lynch syndrome and familial hypercholesterolaemia to all young adults in Australia, compared with the current practice of clinical criteria-based testing for each condition separately. The intervention of genomic screening, assumed as an up-front single cost in the first annual model cycle, would detect pathogenic variants in seven high-risk genes. The simulated population was 18–40 year-olds (8,324,242 individuals), modelling per-sample test costs ranging AU$100–$1200 (base-case AU$200) from the year 2023 onwards with testing uptake of 50 FINDINGS: Over the population lifetime (to age 80 years), the model estimated that genomic screening per-100,000 individuals would lead to 747 QALYs gained by preventing 63 cancers, 31 CHD cases and 97 deaths. In the total model population, this would translate to 31,094 QALYs gained by preventing 2612 cancers, 542 non-fatal CHD events and 4047 total deaths. At AU$200 per-test, genomic screening would require an investment of AU$832 million for screening of 50$23,926 (∼£12,050/€14,110/US$15,345) per QALY gained over the status quo. In scenario analysis with 3$4758/QALY was obtained. Sensitivity analysis for the base case indicated that combined genomic screening would be cost-effective under 70% of simulations, cost-saving under 25% and not cost-effective under 5%. Threshold analysis showed that genomic screening would be cost-effective under the AU$50,000/QALY willingness-to-pay threshold at per-test costs up to AU$325 (∼£164/€192/US$208). INTERPRETATION: Our findings suggest that offering combined genomic screening for high-risk conditions to young adults would be cost-effective in the Australian public healthcare system, at currently realistic testing costs. Other matters, including psychosocial impacts, ethical and societal issues, and implementation challenges, also need consideration. FUNDING: Australian Government, Department of Health, Medical Research Future Fund, Genomics Health Futures Mission (APP2009024). National Heart Foundation Future Leader Fellowship (102604)