Remarks on explicit strong ellipticity conditions for anisotropic or pre-stressed incompressible solids

We present a set of explicit conditions, involving the components of the elastic stiffness tensor, which are necessary and sufficient to ensure the strong ellipticity of an orthorhombic incompressible medium. The derivation is based on the procedure developed by Zee & Sternberg (Arch. Rat. Mech. Anal., 83, 53-90 (1983)) and, consequently, is also applicable to the case of the homogeneously pre-stressed incompressible isotropic solids. This allows us to reformulate the results by Zee & Sternberg in terms of components of the incremental stiffness tensor. In addition, the resulting conditions are specialized to higher symmetry classes and compared with strong ellipticity conditions for plane strain, commonly used in the literature.The first author’s work and the second author’s visit to Brunel University were partly supported by Brunel University’s ‘BRIEF’ award scheme

A cometary ion mass spectrometer

The development of flight suitable analyzer units for that part of the GIOTTO Ion Mass Spectrometer (IMS) experiment designated the High Energy Range Spectrometer (HERS) is discussed. Topics covered include: design of the total ion-optical system for the HERS analyzer; the preparation of the design of analyzing magnet; the evaluation of microchannel plate detectors and associated two-dimensional anode arrays; and the fabrication and evaluation of two flight-suitable units of the complete ion-optical analyzer system including two-dimensional imaging detectors and associated image encoding electronics

Absorption spectrum of iron in the vacuum ultraviolet 2950 - 1588 angstrom

Absorption spectrum of iron in vacuum ultraviole

Experimental atmospheric absorption values from aircraft flyover noise signals

Analysis of aircraft noise recordings to determine experimental values of atmospheric sound absorptio

Search for quarks in cosmic rays

The characteristics of a scintillation counter - neon flash tube telescope have been investigated. The response of the scintillation counter and the efficiency of the neon flash tube trays for relativistic muons was measured. The equivalent characteristics for relativistic ⅓e and ⅔e quarks were evaluated from the above data. The efficiency of the telescope for detecting relativistic ⅓e and ⅔e quarks was thus obtained. The telescope was operated in a search for ⅓ and ⅔e quarks in cosmic rays at sea-level. The telescope was sensitive to ⅓e quarks in the β range 0.4 to 1.0 and to ⅔e quarks in the β range 0.8 to 1,0. In the running time obtained no quarks were detected. The rate of relativistic quarks is given with 90% confidence as: < 1.2.'. x 10(^-10) cm(^- 2) sterad (^-1) sec (^-1) for ⅓e quarks and <8.0 x 10(^-11) cm(^-2) sterad(^-1) sec(^-1) for ⅔e quarks. From these rates the upper limit of the production cross-section for quarks as a function of quark mass was evaluated and compared with theoretical predictions. The characteristics of a glass plate spark chamber and a stack of neon flash tubes operated in the localised discharge regime were investigated

Energy loss of high energy cosmic rays in a liquid scintillator

The characteristics of a large-area liquid scintillation counter are investigated and the uniformity of response of the counter over its area is measured and compared with theory. Using a paraffin phosphor the uniformity is ±8% when the scintillation light is collected by total internal reflection and ±4% when the bottom face of the counter is covered with a diffusing surface. The response of the paraffin phosphor is found to be increased by a factor of 4 by the addition of 10% shellsol A, which makes the response comparable with that of plastic NE 102. The large area scintillation counter is used in an energy loss experiment with a horizontal cosmic ray spectrograph as a "source" of relativistic muons. The results are consistent with conventionally accepted theory to the highest momenta investigated. No evidence is found for a decrease in ionisation loss of high energy muons (momenta >10 GeV/c) as recently predicted by Tsytovich

Biochemical diagnosis of ventricular dysfunction in elderly patients in general practice: observational study

Objective: To investigate the usefulness of measuring plasma concentrations of B type natriuretic peptide in the diagnosis of left ventricular systolic dysfunction in an unselected group of elderly people. Design: Observational study. Setting: General practice with four centres in Poole, Dorset. Participants: 155 elderly patients aged 70 to 84 years. Main outcome measures: Diagnostic characteristics of plasma B type natriuretic peptide measured by radioimmunoassay as a test for left ventricular systolic dysfunction assessed by echocardiography. Results: The median plasma concentration of B type natriuretic peptide was 39.3 pmol/l in patients with left ventricular systolic dysfunction and 15.8 pmol/l in those with normal function. The proportional area under the receiver operator curve was 0.85. At a cut-off point of 18.7 pmol/l the test sensitivity was 92% and the predictive value 18%. Conclusions: Plasma concentration of B type natriuretic peptide could be used effectively as an initial test in a community screening programme and, possibly, using a low cut-off point, as a means of ruling out left ventricular systolic dysfunction. It is, however, not a good test to “rule in” the diagnosis, and access to echocardiography remains essential for general practitioners to diagnose heart failure early

Diffuse gamma radiation

An examination of the intensity, energy spectrum, and spatial distribution of the diffuse gamma-radiation observed by SAS-2 satellite away from the galactic plane in the energy range above 35 MeV has shown that it consists of two components. One component is generally correlated with galactic latitudes, the atomic hydrogen column density was deduced from 21 cm measurements, and the continuum radio emission, believed to be synchrotron emission. It has an energy spectrum similar to that in the plane and joins smoothly to the intense radiation from the plane. It is therefore presumed to be of galactic origin. The other component is apparently isotropic, at least on a coarse scale, and has a steep energy spectrum. No evidence is found for a cosmic ray halo surrounding the galaxy in the shape of a sphere or oblate spheroid with galactic dimensions. Constraints for a halo model with significantly larger dimensions are set on the basis of an upper limit to the gamma-ray anisotropy