50,203 research outputs found
Aluminium or copper substrate panel for selective absorption of solar energy
A method for making panels which selectively absorb solar energy is disclosed. The panels are comprised of an aluminum substrate, a layer of zinc thereon, a layer of nickel over the zinc layer and an outer layer of solar energy absorbing nickel oxide or a copper substrate with a layer of nickel thereon and a layer of solar energy absorbing nickel oxide distal from the copper substrate
Method for making an aluminum or copper substrate panel for selective absorption of solar energy
A panel is described for selectively absorbing solar energy comprising an aluminum substrate. A zinc layer was covered by a layer of nickel and an outer layer of solar energy absorbing nickel oxide or a copper substrate with a nickel layer. A layer of solar energy absorbing nickel oxide distal from the copper substrate was included. A method for making these panels is disclosed
Prevalence of working smoke alarms in local authority inner city housing: randomised controlled trial
Objectives To identify which type of smoke alarm is most likely to remain working in local authority inner city housing, and to identify an alarm tolerated in households with smokers. Design Randomised controlled trial. Setting Two local authority housing estates in inner London. Participants 2145 households. Intervention Installation of one of five types of smoke alarm (ionisation sensor with a zinc battery; ionisation sensor with a zinc battery and pause button; ionisation sensor with a lithium battery and pause button; optical sensor with a lithium battery; or optical sensor with a zinc battery). Main outcome measure Percentage of homes with any working alarm and percentage in which the alarm installed for this study was working after 15 months. Results 54.4% (1166/2145) of all households and 45.9% (465/1012) of households occupied by smokers had a working smoke alarm. Ionisation sensor, lithium battery, and there being a smoker in the household were independently associated with whether an alarm was working (adjusted odds ratios 2.24 (95% confidence interval 1.75 to 2.87), 2.20 (1.77 to 2.75), and 0.62 (0.52 to 0.74)). The most common reasons for non-function were missing battery (19%), missing alarm (17%), and battery disconnected (4%). Conclusions Nearly half of the alarms installed were not working when tested 15 months later. Type of alarm and power source are important determinants of whether a household had a working alarm
Prehension and perception of size in left visual neglect
Right hemisphere damaged patients with and without left visual neglect, and age-matched controls had objects of various sizes presented within left or right body hemispace. Subjects were asked to estimate the objectsâ sizes or to reach out and grasp them, in order to assess visual size processing in perceptual-experiential and action-based contexts respectively. No impairments of size processing were detected in the prehension performance of the neglect patients but a generalised slowing of movement was observed, associated with an extended deceleration phase. Additionally both patient groups reached maximum grip aperture relatively later in the movement than did controls. For the estimation task it was predicted that the left visual neglect group would systematically underestimate the sizes of objects presented within left hemispace but no such abnormalities were observed. Possible reasons for this unexpected null finding are discussed
Fluctuation-induced interactions between dielectrics in general geometries
We study thermal Casimir and quantum non-retarded Lifshitz interactions
between dielectrics in general geometries. We map the calculation of the
classical partition function onto a determinant which we discretize and
evaluate with the help of Cholesky factorization. The quantum partition
function is treated by path integral quantization of a set of interacting
dipoles and reduces to a product of determinants. We compare the approximations
of pairwise additivity and proximity force with our numerical methods. We
propose a ``factorization approximation'' which gives rather good numerical
results in the geometries that we study
Shear dispersion along circular pipes is affected by bends, but the torsion of the pipe is negligible
The flow of a viscous fluid along a curving pipe of fixed radius is driven by
a pressure gradient. For a generally curving pipe it is the fluid flux which is
constant along the pipe and so I correct fluid flow solutions of Dean (1928)
and Topakoglu (1967) which assume constant pressure gradient. When the pipe is
straight, the fluid adopts the parabolic velocity profile of Poiseuille flow;
the spread of any contaminant along the pipe is then described by the shear
dispersion model of Taylor (1954) and its refinements by Mercer, Watt et al
(1994,1996). However, two conflicting effects occur in a generally curving
pipe: viscosity skews the velocity profile which enhances the shear dispersion;
whereas in faster flow centrifugal effects establish secondary flows that
reduce the shear dispersion. The two opposing effects cancel at a Reynolds
number of about 15. Interestingly, the torsion of the pipe seems to have very
little effect upon the flow or the dispersion, the curvature is by far the
dominant influence. Lastly, curvature and torsion in the fluid flow
significantly enhance the upstream tails of concentration profiles in
qualitative agreement with observations of dispersion in river flow
The final results of the ARTISTIC trial: A randomised trial of HPV testing and primary cervical screening
Angular dependence of domain wall resistivity in artificial magnetic domain structures
We exploit the ability to precisely control the magnetic domain structure of
perpendicularly magnetized Pt/Co/Pt trilayers to fabricate artificial domain
wall arrays and study their transport properties. The scaling behaviour of this
model system confirms the intrinsic domain wall origin of the
magnetoresistance, and systematic studies using domains patterned at various
angles to the current flow are excellently described by an angular-dependent
resistivity tensor containing perpendicular and parallel domain wall
resistivities. We find that the latter are fully consistent with Levy-Zhang
theory, which allows us to estimate the ratio of minority to majority spin
carrier resistivities, rho-down/rho-up~5.5, in good agreement with thin film
band structure calculations.Comment: 14 pages, 3 figure
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