11,553 research outputs found

    Changes in Sound Characteristics of Rotary Compressor With Run Time

    Get PDF

    Activities of some enzymes associated with oxygen metablolism, lipid peroxidation and cell permeability in dehydrated Malus micromalus seedlings

    Get PDF
    Measurements were made on the relative water content, cell permeability, superoxide dismutase (SOD) activity, catalase (CAT) activity and malondialdehyde (MDA) content in Malus micromalus seedlingduring dehydration in vitro in whole seedling and during dehydration in culture of different PEG 6000 concentration. The results indicated that SOD and CAT activities increased during dehydration from 0 to 3 h and decreased after dehydration for 3 h; MDA content decreased before 3 h dehydration and the MDA content and cell permeability increased significantly after 3 h in various treatments of dehydration (in vitro and in whole seedling). SOD and CAT activities in 20 days seedlings were higher than those in 10 days seedlings whereas the MDA content and cell permeability in 20 days seedlings were lower than those in 10 days seedlings. In 20 days seedlings during dehydration in vitro, SOD and CAT  activities in leaves were higher than those in root and the latter was higher than those in stem. However, the MDA content and cell permeability in leaves were lower than those in root which in turn were lower than those in stem. Significant correlations and regressions exist among the changes observed in the SOD activity, CAT activity, MDA content, cell permeability and the relative water content

    Calculating the transfer function of noise removal by principal component analysis and application to AzTEC observations

    Get PDF
    Instruments using arrays of many bolometers have become increasingly common in the past decade. The maps produced by such instruments typically include the filtering effects of the instrument as well as those from subsequent steps performed in the reduction of the data. Therefore interpretation of the maps is dependent upon accurately calculating the transfer function of the chosen reduction technique on the signal of interest. Many of these instruments use non-linear and iterative techniques to reduce their data because such methods can offer improved signal-to-noise over those that are purely linear, particularly for signals at scales comparable to that subtended by the array. We discuss a general approach for measuring the transfer function of principal component analysis (PCA) on point sources that are small compared to the spatial extent seen by any single bolometer within the array. The results are applied to previously released AzTEC catalogues of the COSMOS, Lockman Hole, Subaru XMM-Newton Deep Field, GOODS-North and GOODS-South fields. Source flux density and noise estimates increase by roughly +10 per cent for fields observed while AzTEC was installed at the Atacama Submillimeter Telescope Experiment and +15-25 per cent while AzTEC was installed at the James Clerk Maxwell Telescope. Detection significance is, on average, unaffected by the revised technique. The revised photometry technique will be used in subsequent AzTEC releases.Comment: 14 pages, 4 figure

    Powerful High Velocity-Dispersion Molecular Hydrogen Associated with an Intergalactic Shock Wave in Stephan's Quintet

    Get PDF
    We present the discovery of strong mid-infrared emission lines of molecular hydrogen of apparently high velocity dispersion (~870 km/s) originating from a group-wide shock wave in Stephan's Quintet. These Spitzer Space Telescope observations reveal emission lines of molecular hydrogen and little else. this is the first time an almost pure H_2 line spectrum has been seen in an extragalactic object. Along with the absence of PAH features and very low excitation ionized gas tracers, the spectra resemble shocked gas seen in Galactic supernova remnants, but on a vast scale. The molecular emission extends over 24 kpc along the X-ray emitting shock-front, but has ten times the surface luminosity as the soft X-rays, and about one-third the surface luminosity of the IR continuum. We suggest that the powerful H_2 emission is generated by the shock wave caused when a high-velocity intruder galaxy collides with filaments of gas in the galaxy group. Our observations suggest a close connection between galaxy-scale shock-waves and strong broad H_2 emission lines, like those seen in the spectra of Ultraluminous Infrared Galaxies where high-speed collisions between galaxy disks are common.Comment: 4 pages, 4 figures and 1 tabl

    Vibration-Acoustics Study of R410A Rotary Compressors

    Get PDF

    Setting the normalcy level of HI properties in isolated galaxies

    Get PDF
    Studying the atomic gas (HI) properties of the most isolated galaxies is essential to quantify the effect that the environment exerts on this sensitive component of the interstellar medium. We observed and compiled HI data for a well defined sample of ~ 800 galaxies in the Catalog of Isolated Galaxies, as part of the AMIGA project (Analysis of the ISM in Isolated GAlaxies, http://amiga.iaa.es), which enlarges considerably previous samples used to quantify the HI deficiency in galaxies located in denser environments. By studying the shape of 182 HI profiles, we revisited the usually accepted result that, independently of the environment, more than half of the galaxies present a perturbed HI disk. In isolated galaxies this would certainly be a striking result if these are supposed to be the most relaxed systems, and has implications in the relaxation time scales of HI disks and the nature of the most frequent perturbing mechanisms in galaxies. Our sample likely exhibits the lowest HI asymmetry level in the local Universe. We found that other field samples present an excess of ~ 20% more asymmetric HI profiles than that in CIG. Still a small percentage of galaxies in our sample present large asymmetries. Follow-up high resolution VLA maps give insight into the origin of such asymmetries.Comment: 4 pages, 2 figures, Conference 'Galaxies in Isolation: Exploring Nature vs. Nurture', Granada, 12-15 May 2009. To be published in the ASP Conference Serie

    Calculations of polarizabilities and hyperpolarizabilities for the Be+^+ ion

    Get PDF
    The polarizabilities and hyperpolarizabilities of the Be+^+ ion in the 22S2^2S state and the 22P2^2P state are determined. Calculations are performed using two independent methods: i) variationally determined wave functions using Hylleraas basis set expansions and ii) single electron calculations utilizing a frozen-core Hamiltonian. The first few parameters in the long-range interaction potential between a Be+^+ ion and a H, He, or Li atom, and the leading parameters of the effective potential for the high-LL Rydberg states of beryllium were also computed. All the values reported are the results of calculations close to convergence. Comparisons are made with published results where available.Comment: 18 pp; added details to Sec. I

    SXDF-UDS-CANDELS-ALMA 1.5 arcmin2^2 deep survey

    Full text link
    We have conducted 1.1 mm ALMA observations of a contiguous 105′′×50′′105'' \times 50'' or 1.5 arcmin2^2 window in the SXDF-UDS-CANDELS. We achieved a 5σ\sigma sensitivity of 0.28 mJy, providing a flat sensus of dusty star-forming galaxies with LIR∼6×1011L_{\rm IR} \sim6\times10^{11} L⊙L_\odot (for TdustT_{\rm dust} =40K) up to z∼10z\sim10 thanks to the negative K-correction at this wavelength. We detected 5 brightest sources (S/N>>6) and 18 low-significance sources (5>>S/N>>4; these may contain spurious detections, though). One of the 5 brightest ALMA sources (S1.1mm=0.84±0.09S_{\rm 1.1mm} = 0.84 \pm 0.09 mJy) is extremely faint in the WFC3 and VLT/HAWK-I images, demonstrating that a contiguous ALMA imaging survey is able to uncover a faint dust-obscured population that is invisible in deep optical/near-infrared surveys. We found a possible [CII]-line emitter at z=5.955z=5.955 or a low-zz CO emitting galaxy within the field, which may allow us to constrain the [CII] and/or the CO luminosity functions across the history of the universe.Comment: 4 pages, 2 figures, 1 table, to appear in the proceedings of IAU Symposium 319 "Galaxies at High Redshift and Their Evolution over Cosmic Time", eds. S. Kaviraj & H. Ferguso
    • …
    corecore