2,335 research outputs found
Department of Defense Operational Energy Strategy: A Content Analysis of Energy Literature from 1973-2014
Since the 1970s, the U.S. Congress has been concerned with energy policy as a result of the 1973 oil crisis due to the Arab oil embargo. With the Department of Defense (DoD) being the major consumer of energy within the federal government, specifically as it relates to petroleum-related products (gasoline, diesel, and JP8...), it has been directed to implement cost cutting measures related to energy dependence through numerous Executive orders and Congressional Acts. Therefore, the DoD has mandated that each military service find ways to reduce energy requirements in order to meet both Presidential and Congressional mandates. This thesis provides a historical review (1973-2014) of energy related literature and identifies current gaps between strategy and research through the use of content analysis. It focuses primarily on operational energy research, but briefly discusses installation energy as it relates to the DoD Operational Energy Strategy
Scaling relation for determining the critical threshold for continuum percolation of overlapping discs of two sizes
We study continuum percolation of overlapping circular discs of two sizes. We
propose a phenomenological scaling equation for the increase in the effective
size of the larger discs due to the presence of the smaller discs. The critical
percolation threshold as a function of the ratio of sizes of discs, for
different values of the relative areal densities of two discs, can be described
in terms of a scaling function of only one variable. The recent accurate Monte
Carlo estimates of critical threshold by Quintanilla and Ziff [Phys. Rev. E, 76
051115 (2007)] are in very good agreement with the proposed scaling relation.Comment: 4 pages, 3 figure
Effect of spatial inhomogeneity on the mapping between strongly interacting fermions and weakly interacting spins
A combined analytical and numerical study is performed of the mapping between
strongly interacting fermions and weakly interacting spins, in the framework of
the Hubbard, t-J and Heisenberg models. While for spatially homogeneous models
in the thermodynamic limit the mapping is thoroughly understood, we here focus
on aspects that become relevant in spatially inhomogeneous situations, such as
the effect of boundaries, impurities, superlattices and interfaces. We consider
parameter regimes that are relevant for traditional applications of these
models, such as electrons in cuprates and manganites, and for more recent
applications to atoms in optical lattices. The rate of the mapping as a
function of the interaction strength is determined from the Bethe-Ansatz for
infinite systems and from numerical diagonalization for finite systems. We show
analytically that if translational symmetry is broken through the presence of
impurities, the mapping persists and is, in a certain sense, as local as
possible, provided the spin-spin interaction between two sites of the
Heisenberg model is calculated from the harmonic mean of the onsite Coulomb
interaction on adjacent sites of the Hubbard model. Numerical calculations
corroborate these findings also in interfaces and superlattices, where
analytical calculations are more complicated.Comment: 7 pages, 6 figure
Integrating the affective domain when interpreting understanding in mathematics: an operational approach
We present here an integrative proposal allowing to interpret the different systems of the affective domain and its relationship with understanding when performing mathematical activity. A conceptualisation of the affective domain is advanced based on the emotional system, which serves as a central point of reference, and a functional perspective of understanding relating to the uses given to mathematical knowledge. We also provide a specific interpretive method and exemplify it with a practical case of a preservice elementary teacher engaged in solving a flat surface measurement task. To conclude, by incorporating affective phenomena into the interpretation, we found complementary reasons that accounted for the student’s mathematical understanding
Broken time-reversal symmetry probed by muon spin relaxation in the caged type superconductor Lu5Rh6Sn18
The superconducting state of the caged type compound Lu5Rh6Sn18 has been investigated by using magnetization, heat capacity, and muon spin relaxation or rotation (?SR) measurements, and the results interpreted on the basis of the group theoretical classifications of the possible pairing symmetries and a simple model of the resulting quasiparticle spectra. Our zero-field ?SR measurements clearly reveal the spontaneous appearance of an internal magnetic field below the transition temperature, which indicates that the superconducting state in this material is characterized by broken time-reversal symmetry. Further, the analysis of the temperature dependence of the magnetic penetration depth measured using the transverse-field ?SR measurements suggests an isotropic s?wave character for the superconducting gap. This is in agreement with the heat capacity behavior, and we show that it can be interpreted in terms of a nonunitary triplet state with point nodes and an open Fermi surface
A semi-automated method for daily age estimation in larval populations by discriminant function models
Discriminant analysis including the best age-correlated variables selected by SMLR’s to construct a predictive
model based on somatic and otolith biometry was applied. Age of anchovy larvae ranging from
10 to 12 mm collected along Western Mediterranean coasts during MEDIAS209 survey were estimated
by otolith microstructure analysis and compared with the number of daily increments estimated by the
model. The model compound by Perimeter2 + Area2 was able to estimate correctly the age of the otoliths
in 75% of the cases assuming
±1 day of error increasing to 90% assuming
±2 days of error with mean
values of APE (3.33%) and CV (4.71%) systematically low. The results indicate the precision of the increment
estimates. Moreover, no differences between the estimated ages from direct readings and those
estimated by the model were observed. The proposed method implies a reduction in the subjectivity
factor and the cost/benefit ratio for ageing studies in fish larvae.Postprint1,586
On the stability in phase-lag heat conduction with two temperatures
We investigate the well-posedness and the stability of the solutions for several Taylor approximations of the phase-lag two-temperature equations.We give conditions on the parameters which guarantee
the existence and uniqueness of solutions as well as the stability and the instability of the solutions for each approximationPeer ReviewedPostprint (author's final draft
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