3,843 research outputs found
Advanced fiber placement of composite fuselage structures
The Hercules/NASA Advanced Composite Technology (ACT) program will demonstrate the low cost potential of the automated fiber placement process. The Hercules fiber placement machine was developed for cost effective production of composite aircraft structures. The process uses a low cost prepreg tow material form and achieves equivalent laminate properties to structures fabricated with prepreg tape layup. Fiber placement demonstrations planned for the Hercules/NASA program include fabrication of stiffened test panels which represent crown, keel, and window belt segments of a typical transport aircraft fuselage
Development of methodology for thirty-year shoreline projections in the vicinity of beach nourishment projects
The purpose of this report is to develop and illustrate with examples readily applied
methodologies for calculating the response of shorelines in the vicinity of beach nourishment
projects. The need for such methodology is a result of Florida Statutes 161.053(G) and Rule
16B-33.024(3)(e) which require, with minor exceptions, coastal structures to be located
landward of a thirty- year projection of the Seasonal High Water Shoreline (SHWL). (163pp.
Drainage Issues in the Atlantic Canada Offshore Petroleum Industry
In this article, the authors examine the issue of drainage in the Atlantic Canada offshore. The offshore statutory regimes for production of oil and gas, together with the common law, are analyzed for their approaches to dealing with drainage issues. In addition, the law of drainage in Alberta is comprehensively reviewed to provide some guidance as to how the law of drainage may develop in Atlantic Canada
Advanced tow placement of composite fuselage structure
The Hercules NASA ACT program was established to demonstrate and validate the low cost potential of the automated tow placement process for fabrication of aircraft primary structures. The program is currently being conducted as a cooperative program in collaboration with the Boeing ATCAS Program. The Hercules advanced tow placement process has been in development since 1982 and was developed specifically for composite aircraft structures. The second generation machine, now in operation at Hercules, is a production-ready machine that uses a low cost prepreg tow material form to produce structures with laminate properties equivalent to prepreg tape layup. Current program activities are focused on demonstration of the automated tow placement process for fabrication of subsonic transport aircraft fuselage crown quadrants. We are working with Boeing Commercial Aircraft and Douglas Aircraft during this phase of the program. The Douglas demonstration panels has co-cured skin/stringers, and the Boeing demonstration panel is an intricately bonded part with co-cured skin/stringers and co-bonded frames. Other aircraft structures that were evaluated for the automated tow placement process include engine nacelle components, fuselage pressure bulkheads, and fuselage tail cones. Because of the cylindrical shape of these structures, multiple parts can be fabricated on one two placement tool, thus reducing the cost per pound of the finished part
Chabauty-Coleman experiments for genus 3 hyperelliptic curves
We describe a computation of rational points on genus 3 hyperelliptic curves
defined over whose Jacobians have Mordell-Weil rank 1. Using
the method of Chabauty and Coleman, we present and implement an algorithm in
Sage to compute the zero locus of two Coleman integrals and analyze the finite
set of points cut out by the vanishing of these integrals. We run the algorithm
on approximately 17,000 curves from a forthcoming database of genus 3
hyperelliptic curves and discuss some interesting examples where the zero set
includes global points not found in .Comment: 18 page
Outsourcing engineering design in a semiconductor equipment manufacturing company
Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering; in conjunction with the Leaders for Manufacturing Program at MIT, 2003.Includes bibliographical references (p. 97-98).by Robert G. Hacking.S.M.M.B.A
Prescreening and efficiency in the evaluation of integrals over ab initio effective core potentials
New, efficient schemes for the prescreening and evaluation of integrals over effective
core potentials (ECPs) are presented. The screening is shown to give a rigorous,
and close bound, to within on average 10% of the true value. A systematic rescaling
procedure is given to reduce this error to approximately 0.1%. This is then used
to devise a numerically stable recursive integration routine that avoids expensive
quadratures. Tests with CCSD(T) calculations on small silver clusters demonstrate
that the new schemes show no loss in accuracy, while reducing both the power and
prefactor of the scaling with system size. In particular, speedups of roughly 40 times
can be achieved compared to quadrature-based methods
- …