Heat sterilizable Ni-Cd battery development Quarterly report, 1 Apr. - 30 Jun. 1968

Development of heat sterilizable, hermetically sealed nickel cadmium batteries for space application

Thermotropic Nematic and Smectic Order in Silica Glass Nanochannels

Optical birefringence measurements on a rod-like liquid crystal (8OCB), imbibed in silica channels (7 nm diameter), are presented and compared to the thermotropic bulk behavior. The orientational and positional order of the confined liquid evolves continuously at the paranematic-to-nematic and sizeably broadened at the nematic-to-smectic order transition, resp., in contrast to the discontinuous and well-defined second-order character of the bulk transitions. A Landau-de-Gennes analysis reveals identical strengths of the nematic and smectic ordering fields (imposed by the walls) and indicates that the smectic order is more affected by quenched disorder (originating in channel tortuosity and roughness) than the nematic transition.Comment: 3 pages, 4 figure

Heat sterilizable and impact resistant Ni-Cd battery development Quarterly report, 1 Apr. - 30 Jun. 1969

Electrochemistry, battery engineering, and impact tests of heat sterilizable nickel cadmium cell

Relativistic photoelectron spectra in the ionization of atoms by elliptically polarized light

Relativistic tunnel ionization of atoms by intense, elliptically polarized light is considered. The relativistic version of the Landau-Dykhne formula is employed. The general analytical expression is obtained for the relativistic photoelectron spectra. The most probable angle of electron emission, the angular distribution near this angle, the position of the maximum and the width of the energy spectrum are calculated. In the weak field limit we obtain the familiar non-relativistic results. For the case of circular polarization our analytical results are in agreement with recent derivations of Krainov [V.P. Krainov, J. Phys. B, {\bf 32}, 1607 (1999)].Comment: 8 pages, 2 figures, accepted for publication in Journal of Physics

A Comparison of Measured Crab and Vela Glitch Healing Parameters with Predictions of Neutron Star Models

There are currently two well-accepted models that explain how pulsars exhibit glitches, sudden changes in their regular rotational spin-down. According to the starquake model, the glitch healing parameter, Q, which is measurable in some cases from pulsar timing, should be equal to the ratio of the moment of inertia of the superfluid core of a neutron star (NS) to its total moment of inertia. Measured values of the healing parameter from pulsar glitches can therefore be used in combination with realistic NS structure models as one test of the feasibility of the starquake model as a glitch mechanism. We have constructed NS models using seven representative equations of state of superdense matter to test whether starquakes can account for glitches observed in the Crab and Vela pulsars, for which the most extensive and accurate glitch data are available. We also present a compilation of all measured values of Q for Crab and Vela glitches to date which have been separately published in the literature. We have computed the fractional core moment of inertia for stellar models covering a range of NS masses and find that for stable NSs in the realistic mass range 1.4 +/- 0.2 solar masses, the fraction is greater than 0.55 in all cases. This range is not consistent with the observational restriction Q < 0.2 for Vela if starquakes are the cause of its glitches. This confirms results of previous studies of the Vela pulsar which have suggested that starquakes are not a feasible mechanism for Vela glitches. The much larger values of Q observed for Crab glitches (Q > 0.7) are consistent with the starquake model predictions and support previous conclusions that starquakes can be the cause of Crab glitches.Comment: 8 pages, including 3 figures and 1 table. Accepted for publication in Ap

ELKO Spinor Fields: Lagrangians for Gravity derived from Supergravity

Dual-helicity eigenspinors of the charge conjugation operator (ELKO spinor fields) belong -- together with Majorana spinor fields -- to a wider class of spinor fields, the so-called flagpole spinor fields, corresponding to the class-(5), according to Lounesto spinor field classification based on the relations and values taken by their associated bilinear covariants. There exists only six such disjoint classes: the first three corresponding to Dirac spinor fields, and the other three respectively corresponding to flagpole, flag-dipole and Weyl spinor fields. Using the mapping from ELKO spinor fields to the three classes Dirac spinor fields, it is shown that the Einstein-Hilbert, the Einstein-Palatini, and the Holst actions can be derived from the Quadratic Spinor Lagrangian (QSL), as the prime Lagrangian for supergravity. The Holst action is related to the Ashtekar's quantum gravity formulation. To each one of these classes, there corresponds a unique kind of action for a covariant gravity theory. Furthermore we consider the necessary and sufficient conditions to map Dirac spinor fields (DSFs) to ELKO, in order to naturally extend the Standard Model to spinor fields possessing mass dimension one. As ELKO is a prime candidate to describe dark matter and can be obtained from the DSFs, via a mapping explicitly constructed that does not preserve spinor field classes, we prove that in particular the Einstein-Hilbert, Einstein-Palatini, and Holst actions can be derived from the QSL, as a fundamental Lagrangian for supergravity, via ELKO spinor fields. The geometric meaning of the mass dimension-transmuting operator - leading ELKO Lagrangian into the Dirac Lagrangian - is also pointed out, together with its relationship to the instanton Hopf fibration.Comment: 11 pages, RevTeX, accepted for publication in Int.J.Geom.Meth.Mod.Phys. (2009

Discovery of Two High-Magnetic-Field Radio Pulsars

We report the discovery of two young isolated radio pulsars with very high inferred magnetic fields. PSR J1119-6127 has period P = 0.407 s, and the largest period derivative known among radio pulsars, Pdot = 4.0e-12. Under standard assumptions these parameters imply a characteristic spin-down age of only tau = 1.6 kyr and a surface dipole magnetic field strength of B = 4.1e13 G. We have measured a stationary period-second-derivative for this pulsar, resulting in a braking index of n = 2.91+-0.05. We have also observed a glitch in the rotation of the pulsar, with fractional period change Delta_P/P = -4.4e-9. Archival radio imaging data suggest the presence of a previously uncataloged supernova remnant centered on the pulsar. The second pulsar, PSR J1814-1744, has P = 3.975 s and Pdot = 7.4e-13. These parameters imply tau = 85 kyr, and B = 5.5e13 G, the largest of any known radio pulsar. Both PSR J1119-6127 and PSR J1814-1744 show apparently normal radio emission in a regime of magnetic field strength where some models predict that no emission should occur. Also, PSR J1814-1744 has spin parameters similar to the anomalous X-ray pulsar (AXP) 1E 2259+586, but shows no discernible X-ray emission. If AXPs are isolated, high magnetic field neutron stars (``magnetars''), these results suggest that their unusual attributes are unlikely to be merely a consequence of their very high inferred magnetic fields.Comment: 7 pages, 3 embedded EPS figures, to be published in Ap

X-ray observations of the compact central object in supernova remnant G347.3-0.5

We present Chandra, XMM-Newton and RXTE observations of 1WGA J1713.4-3949, a compact source at the center of the galactic supernova remnant (SNR) G347.3-0.5. The X-ray spectrum of the source is well-fitted by the sum of a blackbody component with a temperature of about 0.4 keV plus a power law component with photon index about 4. We found no pulsations down to 4% in the 0.01-0.16 Hz range and down to 25% in the 0.01-128 Hz range. This source resembles other compact central objects (CCOs) in SNRs, and we suggest that 1WGA J1713.4-3949 is the associated neutron star for G347.3--0.5. We also measured the properties of the adjacent radio pulsar PSR J1713-3945 with a 392 ms period and show that it is not associated with 1WGA J1713.4-3949 nor, most probably, with SNR G347.3-0.5 as well.Comment: 8 pages, 2 figures, accepted for publication in ApJ Letter

Abelian Magnetic Monopoles and Topologically Massive Vector Bosons in Scalar-Tensor Gravity with Torsion Potential

A Lagrangian formulation describing the electromagnetic interaction - mediated by topologically massive vector bosons - between charged, spin-(1/2) fermions with an abelian magnetic monopole in a curved spacetime with non-minimal coupling and torsion potential is presented. The covariant field equations are obtained. The issue of coexistence of massive photons and magnetic monopoles is addressed in the present framework. It is found that despite the topological nature of photon mass generation in curved spacetime with isotropic dilaton field, the classical field theory describing the nonrelativistic electromagnetic interaction between a point-like electric charge and magnetic monopole is inconsistent.Comment: 18 pages, no figure