11,060 research outputs found
Buried-Anode Technology Leads to Advanced Lithium Batteries
A technology developed at the National Renewable Energy Laboratory has sparked a start-up company that has attracted funding from the Advanced Projects Research Agency-Energy (ARPA-E). Planar Energy, Inc. has licensed NREL\u27s buried-anode technology and put it to work in solid-state lithium batteries. The company claims its large-format batteries can achieve triple the performance of today\u27s lithium-ion batteries at half the cost, and if so, they could provide a significant boost to the emerging market for electric and plug-in hybrid vehicles
Threshold Resummation in Momentum Space from Effective Field Theory
Methods from soft-collinear effective theory are used to perform the
threshold resummation of Sudakov logarithms for the deep-inelastic structure
function F_2(x,Q^2) in the endpoint region x->1 directly in momentum space. An
explicit all-order formula is derived, which expresses the short-distance
coefficient function C in the convolution F_2=C*phi_q in terms of Wilson
coefficients and anomalous dimensions defined in the effective theory.
Contributions associated with the physical scales Q^2 and Q^2(1-x) are
separated from non-perturbative hadronic physics in a transparent way. A
crucial ingredient to the momentum-space resummation is the exact solution to
the integro-differential evolution equation of the jet function, which is
derived. The methods developed in this Letter can be applied to many other hard
QCD processes.Comment: 4 pages, 1 figure. Version to appear in PR
The location of roots of equations with particular reference to the generalized eigenvalue problem
A survey is presented of algorithms which are in current use for the solution of a single algebraic or transcendental equation in one unknown, together with an appraisal of their practical performance.
The first part of the thesis consists of an account of the theoretical basis of a number of iterative methods and an examination of the problems to be overcome in order to achieve a successful computer implementation.
In the selection of specific programs for testing, the emphasis has been placed on methods which are suitable for use, in conjunction with determinant evaluation, for the solution of standard eigenvalue problems and generalized problems of the form A(λ)x = O, where the elements of A are linear or non-linear functions of λ.
The principal requirements for such purposes are that:
1. the algorithm should not be restricted to polynomial
equations
2. derivative evaluation should not be required.
Examples of eigenvalue problems arising from engineering applications illustrate the potential difficulties of determining roots. Particular attention is given to the problem of calculating a number of roots in cases where a priori estimates for each root are not available. The discussion is extended to give a brief account of possible approaches to the problem of locating complex roots.
Interpolation methods are found to be particularly versatile and can be recommended for their accuracy and efficiency. It is also suggested that such algorithms may often be employed as search strategies in the absence of good initial estimates of the roots. Mention is also made of those features of practical implementation which were found to be particularly useful, together with a list of some outstanding difficulties, associated principally with the automatic computation of several roots of an equation
Biodiesel handling and use guide: Fourth edition (revised)
This document is a guide for those who blend, store, distribute, and use biodiesel and biodiesel blends. It provides basic information on the proper and safe use of biodiesel and biodiesel blends in compression-ignition engines and boilers, and it is intended to help fleets, individual users, blenders, distributors, and those involved in related activities understand procedures for handling and using biodiesel fuels
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