9,173 research outputs found
Why metaphysics matters for the science-theology debate – an incarnational case study
This article examines the relationship between science and theology within a critical realist framework. Focusing on the role of metaphysics as a unifying starting point, especially in consideration of theological issues that are concerned with corporeality and temporality (such as in the incarnation). Some metaphysical challenges that lead to the appearance of “paradox” in the incarnation are highlighted, and the implications of two forms of holistic scientific ontology on the appearance of a paradox in the incarnation are explored. It is concluded that ultimately both science and theology are concerned with the nature of reality, and the search for coherent models that can describe the unseen. Whilst one should maintain a criticality to any realist conception of theological and scientific theories, a shared metaphysics ensures theological doctrine can continue to be interpreted with relevance in a world in which scientific thought is increasingly stretching into the meta-scientific
Shell tile thermal protection system
A reusable, externally applied thermal protection system for use on aerospace vehicles subject to high thermal and mechanical stresses utilizes a shell tile structure which effectively separates its primary functions as an insulator and load absorber. The tile consists of structurally strong upper and lower metallic shells manufactured from materials meeting the thermal and structural requirements incident to tile placement on the spacecraft. A lightweight, high temperature package of insulation is utilized in the upper shell while a lightweight, low temperature insulation is utilized in the lower shell. Assembly of the tile which is facilitated by a self-locking mechanism, may occur subsequent to installation of the lower shell on the spacecraft structural skin
Fitting the Viking lander surface pressure cycle with a Mars General Circulation Model
We present a systematic attempt to fit the Viking lander surface pressure cycle using a Mars General Circulation Model, MarsWRF. Following the earlier study by Wood and Paige (1992) using a one-dimensional model, high-precision fitting was achieved by tuning five time-independent parameters: the albedo and emissivity of the seasonal caps of the two hemispheres and the total CO_2 inventory in the atmosphere frost system. We used a linear iterative method to derive the best fit parameters: albedo of the northern cap = 0.795, emissivity of the northern cap = 0.485, albedo of the southern cap = 0.461, emissivity of the southern cap = 0.785, and total CO_2 mass = 2.83 Ă— 10^(16) kg. If these parameters are used in MarsWRF, the smoothed surface pressure residual at the VL1 site is always smaller than several Pascal through a year. As in other similar studies, the best fit parameters do not match well with the current estimation of the seasonal cap radiative properties, suggesting that important physics contributing to the energy balance not explicitly included in MarsWRF have been effectively aliased into the derived parameters. One such effect is likely the variation of thermal conductivity with depth in the regolith due to the presence of water ice. Including such a parameterization in the fitting process improves the reasonableness of the best fit cap properties, mostly improving the emissivities. The conductivities required in the north to provide the best fit are higher than those required in the south. A completely physically reasonable set of fit parameters could still not be attained. Like all prior published GCM simulations, none of the cases considered are capable of predicting a residual southern CO_2 cap
Neutral Kaon Production From One-prong Tau Decays
The branching ratio for the decay of the tau lepton into at least one neutral kaon meson was measured from a sample of 201850 tau decays recorded by the OPAL detector from 1991 to 1995. The selection yielded 305 t-→X- K0 Lnt candidates (the charge conjugate is implied for all reactions), where X- is any charged hadron possibly accompanied by a neutral particle, giving a branching ratio of B&parl0;t-→X- K 0Lnt&parr0;=&parl0; 10.01±0.79±0.64&parr0;Ă—10- 3, where the first error is statistical and the second is systematic. From the sample of t-→X- K0 Lnt decays, three exclusive decay modes were identified and their branching ratios were measured to be B&parl0;t-→p- K0nt&parr0; =9.1±0.9± 0.6Ă—10-3, B&parl0;t-→p- K0≥1p0n t&parr0;=3.6± 1.3±1.0Ă—10-3, B&parl0;t-→K- K 0≥0p0nt&parr0; =3.3±0.9±0.7 Ă—10-3, where the first error is statistical and the second is systematic. The t- →K*892 -nt branching ratio was determined to be 0.0140 ± 0.0013 using the t- →p-K 0nt branching ratio and assuming isospin conservation. Finally, the ratio of the non-strange decay constant fr to the strange decay constant fK* was measured to be 0.93 ± 0.05
A V-Diagram for the Design of Integrated Health Management for Unmanned Aerial Systems
Designing Integrated Vehicle Health Management (IVHM) for Unmanned Aerial Systems (UAS) is inherently complex. UAS are a system of systems (SoS) and IVHM is a product-service, thus the designer has to take into account many factors, such as: the design of the other systems of the UAS (e.g. engines, structure, communications), the split of functions between elements of the UAS, the intended operation/mission of the UAS, the cost verses benefit of monitoring a system/component/part, different techniques for monitoring the health of the UAS, optimizing the health of the fleet and not just the individual UAS, amongst others. The design of IVHM cannot sit alongside, or after, the design of UAS, but itself be integrated into the overall design to maximize IVHM’s potential.
Many different methods exist to help design complex products and manage the process. One method used is the V-diagram which is based on three concepts: decomposition & definition; integration & testing; and verification & validation. This paper adapts the V-diagram so that it can be used for designing IVHM for UAS. The adapted v-diagram splits into different tracks for the different system elements of the UAS and responses to health states (decomposition and definition). These tracks are then combined into an overall IVHM provision for the UAS (integration and testing), which can be verified and validated. The stages of the adapted V-diagram can easily be aligned with the stages of the V-diagram being used to design the UAS bringing the design of the IVHM in step with the overall design process. The adapted V-diagram also allows the design IVHM for a UAS to be broken down in to smaller tasks which can be assigned to people/teams with the relevant competencies. The adapted V-diagram could also be used to design IVHM for other SoS and other vehicles or products
An Exposition and Calibration of the Ho-Lee Model of Interest Rates
The purpose of this paper is to create an easily understandable version of the Ho-Lee interest rate model. The first part analyzes the model in detail, and the second part calibrates it to demonstrate how it can be applied to real market data
Disparities in the Health Care Status of Women: Implications for Research
Even a cursory review of data on the health status of women reveals striking differences by race. According to data from the National Center for Health Statistics, death rates among Black women from the three leading causes of death (cardiac disease, cancer and cerebrovascular disease) exceed those of white, Asian, Native American and Latina women for each age category from 45-84. With the exception of Black women, the death rates among white women from these diseases exceed those of other ethnic groups of women. Data on two of the risk factors for cardiac and cerebrovascular diseases (hypertension and obesity), show that rates among Black women exceed those of white women by a ratio of 2:1. Overall, the age-adjusted obesity rate between 1976-1980 was 44% among Black women and 24% among white women between the ages 20-74. The 1988-1991 obesity rates for Black and white women were 50% and 34% respectively
A mapping approach to synchronization in the "Zajfman trap". II: the observed bunch
We extend a recently introduced mapping model, which explains the bunching
phenomenon in an ion beam resonator for two ions [Geyer, Tannor, J. Phys. B 37
(2004) 73], to describe the dynamics of the whole ion bunch. We calculate the
time delay of the ions from a model of the bunch geometry and find that the
bunch takes on a spherical form at the turning points in the electrostatic
mirrors. From this condition we derive how the observed bunch length depends on
the experimental parameters. We give an interpretation of the criteria for the
existence of the bunch, which were derived from the experimental observations
by Pedersen et al [Pedersen etal, Phys. Rev. A 65 042704].Comment: 25 pages, 6 figures; added new section 5 and clarified text;
submitted to J. Phys.
Quantum oscillations in topological superconductor candidate CuBiSe
Quantum oscillations are generally studied to resolve the electronic
structure of topological insulators. In CuBiSe, the prime
candidate of topological superconductors, quantum oscillations are still not
observed in magnetotransport measurement. However, using torque magnetometry,
quantum oscillations (the de Hass - van Alphen effect) were observed in
CuBiSe . The doping of Cu in BiSe increases the
carrier density and the effective mass without increasing the scattering rate
or decreasing the mean free path. In addition, the Fermi velocity remains the
same in CuBiSe as that in BiSe. Our results imply that
the insertion of Cu does not change the band structure of BiSe.Comment: 5 pages, 4 figure
Seniority conservation and seniority violation in the g_{9/2} shell
The g_{9/2} shell of identical particles is the first one for which one can
have seniority-mixing effects. We consider three interactions: a delta
interaction that conserves seniority, a quadrupole-quadrupole (QQ) interaction
that does not, and a third one consisting of two-body matrix elements taken
from experiment (98Cd) that also leads to some seniority mixing. We deal with
proton holes relative to a Z=50,N=50 core. One surprising result is that, for a
four-particle system with total angular momentum I=4, there is one state with
seniority v=4 that is an eigenstate of any two-body interaction--seniority
conserving or not. The other two states are mixtures of v=2 and v=4 for the
seniority-mixing interactions. The same thing holds true for I=6. Another point
of interest is that the splittings E(I_{max})-E(I_{min}) are the same for three
and five particles with a seniority conserving interaction (a well known
result), but are equal and opposite for a QQ interaction. We also fit the
spectra with a combination of the delta and QQ interactions. The Z=40,N=40 core
plus g_{9/2} neutrons (Zr isotopes) is also considered, although it is
recognized that the core is deformed.Comment: 19 pages, 9 figures; RevTeX4. We have corrected the SDI values in
Table1 and Fig.1; in Sect.VII we have included an explanation of Fig.3
through triaxiality; we have added comments of Figs.10-12 in Sect.IX; we have
removed Figs.7-
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