31,931 research outputs found

    An efficient prebreathing apparatus for humans during decompression

    Get PDF
    Portable prebreathing system was developed which recirculates and reconditions respiratorily exhaled oxygen. Apparatus reduces fire hazards, simplifies prebreathing procedures, and does not require extensive enclosure venting system usage

    The June 2012 transit of Venus. Framework for interpretation of observations

    Get PDF
    Ground based observers have on 5/6th June 2012 the last opportunity of the century to watch the passage of Venus across the solar disk from Earth. Venus transits have traditionally provided unique insight into the Venus atmosphere through the refraction halo that appears at the planet outer terminator near ingress/egress. Much more recently, Venus transits have attracted renewed interest because the technique of transits is being successfully applied to the characterization of extrasolar planet atmospheres. The current work investigates theoretically the interaction of sunlight and the Venus atmosphere through the full range of transit phases, as observed from Earth and from a remote distance. Our model predictions quantify the relevant atmospheric phenomena, thereby assisting the observers of the event in the interpretation of measurements and the extrapolation to the exoplanet case. Our approach relies on the numerical integration of the radiative transfer equation, and includes refraction, multiple scattering, atmospheric extinction and solar limb darkening, as well as an up to date description of the Venus atmosphere. We produce synthetic images of the planet terminator during ingress/egress that demonstrate the evolving shape, brightness and chromaticity of the halo. Guidelines are offered for the investigation of the planet upper haze from vertically-unresolved photometric measurements. In this respect, the comparison with measurements from the 2004 transit appears encouraging. We also show integrated lightcurves of the Venus/Sun system at various phases during transit and calculate the respective Venus-Sun integrated transmission spectra. The comparison of the model predictions to those for a Venus-like planet free of haze and clouds (and therefore a closer terrestrial analogue) complements the discussion and sets the conclusions into a broader perspective.Comment: 14 pages; 14 figures; Submitted on 02/06/2012; A&A, accepted for publication on 30/08/201

    Thermal infrared spectroscopy of Europa and Callisto

    Get PDF
    The trailing hemispheres of Europa and Callisto were observed at 9–13 μm, and a spectrum of Europa with better spectral resolution and a better signal-to-noise ratio than was previously possible has been derived. The ratio spectrum of the two satellites has a signal-to-noise ratio of approximately 30 for a spectral resolving power of approximately 50. The disk-integrated, effective color temperature ratio for the two satellites is consistent with broadband, thermal infrared photometry from previous ground-based studies and from the Galileo photopolarimeter radiometer. The ratio spectrum was combined with the average Voyager 1 spectrum of Callisto to obtain a 9–13 μm spectrum of Europa with a signal-to-noise ratio that is a factor of 10 better than that in the average Voyager spectrum of Europa. After convolving the measured spectrum to the expected width of water ice emissivity features, ∼1 μm, no spectral features that could be attributed to water ice on the surface of Europa are apparent at the 0.6–0.7% level. The absence of spectral features attributable to water ice is consistent with the proposal that the equatorial region of Europa that was observed may be composed primarily of a heavily hydrated mineral. The absence of water ice features may also be the result of a large fractional abundance of fine particles, such as that found on the surface of the Moon

    Computer modeling of rocket engine ignition transients Final report

    Get PDF
    Computer modeling of rocket engine ignition transient

    Raised serum transaminases during treatment with pegylated interferon for chronic hepatiti C

    Get PDF
    Introduction : Serum transaminases rose significantly in 7 patients with chronic hepatitis C, genotypes 2 and 3, who were treated with pegylated interferon and ribavirin. Methods : 219 patients with chronic hepatitis C, genotypes 2 and 3, were treated between 2005 and 2011 following the same protocol. For the 7 patients presented in this paper, the initial liver screen revealed chronic hepatitis C infection only. The same liver screen was repeated following the transaminase rise during the treatment period and failed to reveal additional comorbidity. Results : 5 male and 2 female patients with chronic hepatitis C experienced a rise in serum transaminases after commencement on treatment with pegylated interferon and ribavirin. They all achieved rapid and end of treatment virological responses. 3 of the patients achieved sustained virological response and 4 relapsed. There was no evidence to suggest that steatosis, development of autoimmunity or intercurrent illness was the cause of the liver injury. In 3 out of 7 patients, the level of transaminases exhibited a downward trend after pegylated interferon was changed to non pegylated interferon. Additionally, it is evident that in those patients whose treatment was temporarily or permanently aborted, the rise in transaminases rapidly improved and returned to baseline. Conclusion : Our experience suggests the possibility of a toxic reaction to polyethylene glycol in a small number of patients being treated with pegylated interferon, resulting in an acute hepatitic response which resolved when therapy was stopped or switched to non-pegylated interferon

    A critical analysis of the hydrino model

    Full text link
    Recently, spectroscopic and calorimetric observations of hydrogen plasmas and chemical reactions with them have been interpreted as evidence for the existence of electronic states of the hydrogen atom with a binding energy of more than 13.6 eV. The theoretical basis for such states, that have been dubbed hydrinos, is investigated. We discuss both, the novel deterministic model of the hydrogen atom, in which the existence of hydrinos was predicted, and standard quantum mechanics. Severe inconsistencies in the deterministic model are pointed out and the incompatibility of hydrino states with quantum mechanics is reviewed.Comment: 9 page

    Induction of disease resistance to anthracnose in cucumber

    Get PDF
    Imperial Users onl
    • …
    corecore