588 research outputs found

    A study of low density, high strength high modulus filaments and composites

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    Filament and whisker reinforcement of low density, high strength, high modulus composites - metallic and ceramic layers alternated in multilaminar composite

    Development of dispersion strengthened chromium alloys Summary report

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    Dispersion strengthened chromium alloys with minimal quantities of interstitial impuritie

    Measuring Diesel Fuel Consumption in a Laboratory Setting

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    Several improvements in diesel engines attribute from additional hardware and calibrations. To continue the improvement of diesel engines, it is necessary to study these increasingly complex systems with accuracy. Specifically, measuring engine fuel consumption requires a system that can account for any fluctuations in fuel properties (e.g., temperature and pressure) to yield accurate results. Current fuel consumption measurement systems on the market are accurate, however they are expensive. This research develops a more affordable design that is capable of measuring fuel consumption at equal accuracy. In this study, an older, retail fuel measurement system was used as a comparison with the newly designed fuel measurement system. A bill of materials was recorded during the building process. For precautionary measures, a controlled amount of water was run through the new measurement system to test safety and functionality. The new measurement system was then attached to a diesel engine, and fuel consumption was measured using the gravimetric method at controlled speeds/torques to test repeatability. Finally, fuel consumption was compared with previously acquired data from the old measurement system to test for accuracy. Results show the new measurement system is about 10 times cheaper than the old measurement system. The new measurement system has a repeatability error of 0.66%, while the old fuel measuring system has a repeatability error of 0.77%. By providing a more cost-effective product for engine testing, a larger range of researchers can conduct engine testing in a laboratory setting. This creates potential for further improvements to be made in diesel engines

    High-Efficiency Control Systems for Connected Class 8 Trucks

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    The Department of Energy–sponsored project Next-Generation Energy Technologies for Connected and Automated On-Road Vehicles (NEXTCAR) aims to develop technologies that utilize emerging connectivity infrastructure. A Purdue University–led team of industry leaders, along with the National Renewable Energy Laboratory, is focusing on technologies that benefit line-haul Class 8 trucks, with an emphasis on platooning vehicles. The goal is an integrated, connectivity-enabled vehicle and powertrain control system for diesel-powered on-highway trucks. Join us for a discussion

    A Chandra Observation of the Obscured Star-Forming Complex W40

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    The young stellar cluster illuminating the W40 H II region, one of the nearest massive star forming regions, has been observed with the ACIS detector on board the Chandra X-ray Observatory. Due to its high obscuration, this is a poorly-studied stellar cluster with only a handful of bright stars visible in the optical band, including three OB stars identified as primary excitation sources. We detect 225 X-ray sources, of which 85% are confidently identified as young stellar members of the region. Two potential distances of the cluster, 260 pc and 600 pc, are used in the paper. Supposing the X-ray luminosity function to be universal, it supports a 600 pc distance as a lower limit for W40 and a total population of at least 600 stars down to 0.1 Mo under the assumption of a coeval population with a uniform obscuration. In fact, there is strong spatial variation in Ks-band-excess disk fraction and non-uniform obscuration due to a dust lane that is identified in absorption in optical, infrared and X-ray. The dust lane is likely part of a ring of material which includes the molecular core within W40. In contrast to the likely ongoing star formation in the dust lane, the molecular core is inactive. The star cluster has a spherical morphology, an isothermal sphere density profile, and mass segregation down to 1.5 Mo. However, other cluster properties, including a \leq{1} Myr age estimate and ongoing star formation, indicate that the cluster is not dynamically relaxed. X-ray diffuse emission and a powerful flare from a young stellar object are also reported.Comment: Accepted for publication in The Astrophysical Journal. 60 pages, 16 figure

    Simple nutrients bypass the requirement for HLH-30 in coupling lysosomal nutrient sensing to survival

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    Lysosomes are ubiquitous acidified organelles that degrade intracellular and extracellular material trafficked via multiple pathways. Lysosomes also sense cellular nutrient levels to regulate target of rapamycin (TOR) kinase, a signaling enzyme that drives growth and suppresses activity of the MiT/TFE family of transcription factors that control biogenesis of lysosomes. In this study, we subjected worms lacking basic helix–loop–helix transcription factor 30 (hlh-30), the Caenorhabditis elegans MiT/TFE ortholog, to starvation followed by refeeding to understand how this pathway regulates survival with variable nutrient supply. Loss of HLH-30 markedly impaired survival in starved larval worms and recovery upon refeeding bacteria. Remarkably, provision of simple nutrients in a completely defined medium (C. elegans maintenance medium [CeMM]), specifically glucose and linoleic acid, restored lysosomal acidification, TOR activation, and survival with refeeding despite the absence of HLH-30. Worms deficient in lysosomal lipase 2 (lipl-2), a lysosomal enzyme that is transcriptionally up-regulated in starvation in an HLH-30–dependent manner, also demonstrated increased mortality with starvation–refeeding that was partially rescued with glucose, suggesting a critical role for LIPL-2 in lipid metabolism under starvation. CeMM induced transcription of vacuolar proton pump subunits in hlh-30 mutant worms, and knockdown of vacuolar H+-ATPase 12 (vha-12) and its upstream regulator, nuclear hormone receptor 31 (nhr-31), abolished the rescue with CeMM. Loss of Ras-related GTP binding protein C homolog 1 RAGC-1, the ortholog for mammalian RagC/D GTPases, conferred starvation–refeeding lethality, and RAGC-1 overexpression was sufficient to rescue starved hlh-30 mutant worms, demonstrating a critical need for TOR activation with refeeding. These results show that HLH-30 activation is critical for sustaining survival during starvation–refeeding stress via regulating TOR. Glucose and linoleic acid bypass the requirement for HLH-30 in coupling lysosome nutrient sensing to survival.</div

    A Physical Model for z~2 Dust Obscured Galaxies

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    We present a physical model for the origin of z~2 Dust-Obscured Galaxies (DOGs), a class of high-redshift ULIRGs selected at 24 micron which are particularly optically faint (24/R>1000). By combining N-body/SPH simulations of high redshift galaxy evolution with 3D polychromatic dust radiative transfer models, we find that luminous DOGs (with F24 > 0.3 mJy at z~2 are well-modeled as extreme gas-rich mergers in massive (~5x10^12-10^13 Msun) halos, with elevated star formation rates (~500-1000 Msun/yr) and/or significant AGN growth (Mdot > 0.5 Msun/yr), whereas less luminous DOGs are more diverse in nature. At final coalescence, merger-driven DOGs transition from being starburst dominated to AGN dominated, evolving from a "bump" to a power-law shaped mid-IR (IRAC) spectral energy distribution (SED). After the DOG phase, the galaxy settles back to exhibiting a "bump" SED with bluer colors and lower star formation rates. While canonically power-law galaxies are associated with being AGN-dominated, we find that the power-law mid-IR SED can owe both to direct AGN contribution, as well as to a heavily dust obscured stellar bump at times that the galaxy is starburst dominated. Thus power-law galaxies can be either starburst or AGN dominated. Less luminous DOGs can be well-represented either by mergers, or by massive ($M_{\rm baryon} ~5x10^11 Msun) secularly evolving gas-rich disc galaxies (with SFR > 50 Msun/yr). By utilising similar models as those employed in the SMG formation study of Narayanan et al. (2010), we investigate the connection between DOGs and SMGs. We find that the most heavily star-forming merger driven DOGs can be selected as Submillimetre Galaxies (SMGs), while both merger-driven and secularly evolving DOGs typically satisfy the BzK selection criteria.Comment: Accepted by MNRAS; major changes include better description of dependency on ISM specification and updated models allowing dust to evolve with metallicity

    Gender-specific aspects in the clinical presentation of cardiovascular disease

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    More than a quarter of a million women die each year in the industrialized countries from cardiovascular diseases (CVD), and current projections indicate that this number will continue to rise with our ageing population. Important sex-related differences in the prevalence, presentation, management and outcomes of different CVD have discovered in the last two decades of cardiovascular research. Nevertheless, much evidence supporting contemporary recommendations for testing, prevention and treatment of CVD in women is still extrapolated from studies conducted predominantly in men. The compendium of CVD indicates that current research and strategy development must focus on gender-specific issues to address the societal burden and costs related to these incremental shifts in female gender involvement. Indeed, this significant burden of CVD in women places unique diagnostic, treatment and financial encumbrances on our society that are only further intensified by a lack of public awareness about the disease on the part of patients and clinicians alike. This societal burden of the disease is, in part, related to our poor understanding of gender-specific pathophysiologic differences in the presentation and prognosis of CVD and the paucity of diagnostic and treatment guidelines tailored to phenotypic differences in women. In this, scenario is of outmost importance to know these differences to provide the best care for female patients, because under-recognition of CVD in women may contribute to a worse clinical outcome. This review will provide a synopsis of available evidence on gender-based differences in the initial presentation, pathophysiology and clinical outcomes of women affected by CVD. © 2010 The Authors Fundamental and Clinical Pharmacology © Société Française de Pharmacologie et de Thérapeutique
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