98,654 research outputs found
Carbon dioxide concentrator
Passed exhaled air through electrochemical cell containing alkali metal carbonate aqueous solution, and utilizes platinized electrodes causing reaction of oxygen at cathode with water in electrolyte, producing hydroxyl ions which react with carbon dioxide to form carbonate ions
A Study of Display Integration for Hypersonic Research Vehicles First Quarterly Progress Report, 16 May - 16 Aug. 1963
Contact analog television display for X-15 pilot flight control informatio
Inflating with Large Effective Fields
We re-examine large scalar fields within effective field theory, in
particular focussing on the issues raised by their use in inflationary models
(as suggested by BICEP2 to obtain primordial tensor modes). We argue that when
the large-field and low-energy regimes coincide the scalar dynamics is most
effectively described in terms of an asymptotic large-field expansion whose
form can be dictated by approximate symmetries, which also help control the
size of quantum corrections. We discuss several possible symmetries that can
achieve this, including pseudo-Goldstone inflatons characterized by a coset
(based on abelian and non-abelian, compact and non-compact symmetries),
as well as symmetries that are intrinsically higher dimensional. Besides the
usual trigonometric potentials of Natural Inflation we also find in this way
simple {\em large-field} power laws (like ) and exponential
potentials, . Both of these can
describe the data well and give slow-roll inflation for large fields without
the need for a precise balancing of terms in the potential. The exponential
potentials achieve large through the limit and so
predict ; consequently gives but not much larger (and so could be ruled out as measurements on
and improve). We examine the naturalness issues for these models and
give simple examples where symmetries protect these forms, using both
pseudo-Goldstone inflatons (with non-abelian non-compact shift symmetries
following familiar techniques from chiral perturbation theory) and
extra-dimensional models.Comment: 21 pages + appendices, 3 figure
On direction of spontaneous magnetization in a "cubic" ferromagnet
The magnetic properties of anisotropic films have been studied using
3D-neutron polarization analysis. The experimental facts refer to essential
distinction of the sample states, magnetized in opposite directions. For an
explanation of asymmetrical effects the model is offered, in which the
fundamental theoretical principles of structural phase transitions are used.Comment: 4 pages LaTeX (phbauth) and 4 figures (epsfig
Space telescope observatory management system preliminary test and verification plan
The preliminary plan for the Space Telescope Observatory Management System Test and Verification (TAV) is provided. Methodology, test scenarios, test plans and procedure formats, schedules, and the TAV organization are included. Supporting information is provided
Rotor redesign for a highly loaded 1800 ft/sec tip speed fan. 3: Laser Doppler velocimeter report
Laser Doppler velocimeter (LDV) techniques were employed for testing a highly loaded, 550 m/sec (1800 ft/sec) tip speed, test fan stage, the objective to provide detailed mapping of the upstream, intrablade, and downstream flowfields of the rotor. Intrablade LDV measurements of velocity and flow angle were obtained along four streamlines passing through the leading edge at 45%, 69%, 85%, and 95% span measured from hub to tip, at 100% of design speed, peak efficiency; 100% speed, near surge; and 95% speed, peak efficiency. At the design point, most passages appeared to have a strong leading edge shock, which moved forward with increasing strength near surge and at part speeds. The flow behind the shock was of a complex mixed subsonic and supersonic form. The intrablade flowfields were found to be significantly nonperiodic at 100% design speed, peak efficiency
Monitoring the defoliation of hardwood forests in Pennsylvania using LANDSAT
An automated system for conducting annual gypsy moth defoliation surveys using LANDSAT MSS data and digital processing techniques is described. A two-step preprocessing procedure was developed that uses multitemporal data sets representing forest canopy conditions before and after defoliation to create a digital image in which all nonforest cover types are eliminated or masked out of a LANDSAT image that exhibits insect defoliation. A temporal window for defoliation assessment was identified and a statewide data base was established. A data management system to interface image analysis software with the statewide data base was developed and a cost benefit analysis of this operational system was conducted
Variational semi-blind sparse deconvolution with orthogonal kernel bases and its application to MRFM
We present a variational Bayesian method of joint image reconstruction and point spread function (PSF) estimation when the PSF of the imaging device is only partially known. To solve this semi-blind deconvolution problem, prior distributions are specified for the PSF and the 3D image. Joint image reconstruction and PSF estimation is then performed within a Bayesian framework, using a variational algorithm to estimate the posterior distribution. The image prior distribution imposes an explicit atomic measure that corresponds to image sparsity. Importantly, the proposed Bayesian deconvolution algorithm does not require hand tuning. Simulation results clearly demonstrate that the semi-blind deconvolution algorithm compares favorably with previous Markov chain Monte Carlo (MCMC) version of myopic sparse reconstruction. It significantly outperforms mismatched non-blind algorithms that rely on the assumption of the perfect knowledge of the PSF. The algorithm is illustrated on real data from magnetic resonance force microscopy (MRFM)
Mapping Low-Density Intergalactic Gas: a Third Helium Lyman-alpha Forest
We present a new HST/STIS spectrum of the z=3.18 quasar PKS 1935-692 and
summarize the spectral features shortwards of 304A in the rest frame likely to
be caused by foreground HeII Lyman-alpha absorption. In accord with previous
results on two other quasars at similar redshifts, we demonstrate a correlation
with the HI Lyman-alpha forest absorption, and show that much of the helium
absorption is caused by a comparable quantity of more diffuse gas with
Omega~0.01, that is not detected in HI. The helium ionization zone around the
quasar is detected as well as a void seen in both HI and HeII. The properties
of the absorption are in broad agreement with those of the other quasars and
with models of the protogalactic gas distribution and ionization at this
redshift.Comment: 17 pages including 5 figures. As accepted for publication in The
Astronomical Journal (minor revisions
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