Aerospace nickel-cadmium cell separator qualifications program

The present space qualified nylon separator, Pellon 2505 ML, is no longer available for aerospace nickel-cadmium (NiCd) cells. As a result of this anticipated unavailability, a joint Government program between the Air Force Space Division and the Naval Research Laboratory was established. Four cell types were procured with both the old qualified and the new unqualified separators. Acceptance, characterization, and life cycling tests are to be performed at the Naval Weapons Support Center, Crane, Ind. (NWSC/Crane). The scheduling and current status of this program are discussed and the progress of testing and available results are projected

Two years of on-orbit gallium arsenide performance from the LIPS solar cell panel experiment

The LIPS on-orbit performance of the gallium arsenide panel experiment was analyzed from flight operation telemetry data. Algorithms were developed to calculate the daily maximum power and associated solar array parameters by two independent methods. The first technique utilizes a least mean square polynomial fit to the power curve obtained with intensity and temperature corrected currents and voltages; whereas, the second incorporates an empirical expression for fill factor based on an open circuit voltage and the calculated series resistance. Maximum power, fill factor, open circuit voltage, short circuit current and series resistance of the solar cell array are examined as a function of flight time. Trends are analyzed with respect to possible mechanisms which may affect successive periods of output power during 2 years of flight operation. Degradation factors responsible for the on-orbit performance characteristics of gallium arsenide are discussed in relation to the calculated solar cell parameters. Performance trends and the potential degradation mechanisms are correlated with existing laboratory and flight data on both gallium arsenide and silicon solar cells for similar environments

Mystical orientation and the perceiving process : a study among Anglican clergymen

This study examines the hypothesised link between mystical orientation and the perceiving process within the Jungian model of psychological type. Data were provided by 232 Anglican clergymen serving in the Church in Wales who completed both the Francis-Louden Mystical Orientation Scale and the Francis Psychological Type Scales. The data demonstrated that intuitive types recorded significantly higher scores than sensing types on the index of mystical orientation, supporting the hypothesis based on Ross' thesis

Thermal stress cycling of GaAs solar cells

A thermal cycling experiment was performed on GaAs solar cells to establish the electrical and structural integrity of these cells under the temperature conditions of a simulated low-Earth orbit of 3-year duration. Thirty single junction GaAs cells were obtained and tests were performed to establish the beginning-of-life characteristics of these cells. The tests consisted of cell I-V power output curves, from which were obtained short-circuit current, open circuit voltage, fill factor, and cell efficiency, and optical micrographs, spectral response, and ion microprobe mass analysis (IMMA) depth profiles on both the front surfaces and the front metallic contacts of the cells. Following 5,000 thermal cycles, the performance of the cells was reexamined in addition to any factors which might contribute to performance degradation. It is established that, after 5,000 thermal cycles, the cells retain their power output with no loss of structural integrity or change in physical appearance

Measuring attitude toward theistic faith : assessing the Astley-Francis Scale among Christian, Muslim and secular youth in England

Empirical research within the social scientific study of religion in general and within the psychology of religion in particular remains very conscious of the complex nature of its subject matter. Empirical research in this field needs to take cognisance of the many forms in which religion is expressed (say, Buddhism, Christianity, Hinduism, Islam, Judaism, and Sikhism) and the many facets within the forms (say, beliefs, behaviours and affiliation). Working in the 1970s, Francis (1978a; 1978b) advanced the view that the attitudinal dimension of religion offered a particularly fruitful basis for coordinating empirical enquiry into the correlates, antecedents and consequences of religiosity across the life span

Effective anisotropies and energy barriers of magnetic nanoparticles with Néel surface anisotropy

Magnetic nanoparticles with Néel surface anisotropy, different internal structures, surface arrangements, and elongation are modeled as many-spin systems. The results suggest that the energy of many-spin nanoparticles cut from cubic lattices can be represented by an effective one-spin potential containing uniaxial and cubic anisotropies. It is shown that the values and signs of the corresponding constants depend strongly on the particle's surface arrangement, internal structure, and shape. Particles cut from a simple cubic lattice have the opposite sign of the effective cubic term, as compared to particles cut from the face-centered cubic lattice. Furthermore, other remarkable phenomena are observed in nanoparticles with relatively strong surface effects. (i) In elongated particles surface effects can change the sign of the uniaxial anisotropy. (ii) In symmetric particles (spherical and truncated octahedral) with cubic core anisotropy surface effects can change the sing of the latter. We also show that the competition between the core and surface anisotropies leads to a new energy that contributes to both the second- and fourth-order effective anisotropies. We evaluate energy barriers ΔE as functions of the strength of the surface anisotropy and the particle size. The results are analyzed with the help of the effective one-spin potential, which allows us to assess the consistency of the widely used formula ΔE/V= K∞ +6 Ks /D, where K∞ is the core anisotropy constant, Ks is a phenomenological constant related to surface anisotropy, and D is the particle's diameter. We show that the energy barriers are consistent with this formula only for elongated particles for which the surface contribution to the effective uniaxial anisotropy scales with the surface and is linear in the constant of the Néel surface anisotropy. © 2007 The American Physical Society

Growth or decline in the Church of England during the decade of Evangelism: did the Churchmanship of the Bishop matter?

The Decade of Evangelism occupied the attention of the Church of England throughout the 1990s. The present study employs the statistics routinely published by the Church of England in order to assess two matters: the extent to which these statistics suggest that the 43 individual dioceses finished the decade in a stronger or weaker position than they had entered it and the extent to which, according to these statistics, the performance of dioceses led by bishops shaped in the Evangelical tradition differed from the performance of dioceses led by bishops shaped in the Catholic tradition. The data demonstrated that the majority of dioceses were performing less effectively at the end of the decade than at the beginning, in terms of a range of membership statistics, and that the rate of decline varied considerably from one diocese to another. The only exception to the trend was provided by the diocese of London, which experienced some growth. The data also demonstrated that little depended on the churchmanship of the diocesan bishop in shaping diocesan outcomes on the performance indicators employed in the study

Interpenetration as a Mechanism for Liquid-Liquid Phase Transitions

We study simple lattice systems to demonstrate the influence of interpenetrating bond networks on phase behavior. We promote interpenetration by using a Hamiltonian with a weakly repulsive interaction with nearest neighbors and an attractive interaction with second-nearest neighbors. In this way, bond networks will form between second-nearest neighbors, allowing for two (locally) distinct networks to form. We obtain the phase behavior from analytic solution in the mean-field approximation and exact solution on the Bethe lattice. We compare these results with exact numerical results for the phase behavior from grand canonical Monte Carlo simulations on square, cubic, and tetrahedral lattices. All results show that these simple systems exhibit rich phase diagrams with two fluid-fluid critical points and three thermodynamically distinct phases. We also consider including third-nearest-neighbor interactions, which give rise to a phase diagram with four critical points and five thermodynamically distinct phases. Thus the interpenetration mechanism provides a simple route to generate multiple liquid phases in single-component systems, such as hypothesized in water and observed in several model and experimental systems. Additionally, interpenetration of many such networks appears plausible in a recently considered material made from nanoparticles functionalized by single strands of DNA.Comment: 12 pages, 9 figures, submitted to Phys. Rev.

X-ray properties of the Parkes sample of flat-spectrum radio sources: dust in radio-loud quasars?

We investigate the X-ray properties of the Parkes sample of flat-spectrum radio sources using data from the ROSAT All-Sky Survey and archival pointed PSPC observations. In total, 163 of the 323 sources are detected. For the remaining 160 sources 2 sigma upper limits to the X-ray flux are derived. We present power-law photon indices for 115 sources, which were either determined with a hardness ratio technique or from direct fits to pointed PSPC data. For quasars, the soft X-ray photon index is correlated with redshift and with radio spectral index. Webster et al. (1995) discovered many sources with unusually red optical continua among the quasars of this sample and interpreted this result in terms of extinction by dust. Although the X-ray spectra in general do not show excess absorption, we find that low-redshift optically red quasars have significantly lower soft X-ray luminosities on average than objects with blue optical continua. The difference disappears for higher redshifts, as is expected for intrinsic absorption by cold gas associated with the dust. Alternative explanations are briefly discussed. We conclude, however, that dust does play an important role in some of the radio-loud quasars with red optical continua.Comment: 21 pages, 13 figures, to appear in MNRA

Impurity-assisted Andreev reflection at a spin-active half-metal-superconductor interface

The Andreev reflection amplitude at a clean interface between a half-metallic ferromagnet (H) and a superconductor (S) for which the half metal's magnetization has a gradient perpendicular to the interface is proportional to the excitation energy $\varepsilon$ and vanishes at $\varepsilon=0$ [B\'{e}ri {\em et al.}, Phys.\ Rev.\ B {\bf 79}, 024517 (2009)]. Here we show that the presence of impurities at or in the immediate vicinity of the HS interface leads to a finite Andreev reflection amplitude at $\varepsilon=0$. This impurity-assisted Andreev reflection dominates the low-bias conductance of a HS junction and the Josephson current of an SHS junction in the long-junction limit.Comment: 12 pages, 2 figure