356 research outputs found
SSR⢠Semi-Solid Rheocasting
Il processo IdraPrince SSR⢠(Semi-Solid Rheocasting) è una nuova tecnologia sviluppata da Idraprofondamente diversa da tutti gli altri processi sviluppati precedentemente nellâarea delle leghe allostato semi-solido. A differenza delle altre tecnologie il vantaggio competitivo dellâSSR⢠è di utilizzareleghe commerciali secondarie quali EN 46000, senza aggravio di costi della materia prima permigliorare la qualitĂ dei getti utilizzando macchine di pressofusione tradizionali.In questo modo la tecnologia SSR⢠diventa giustificata non solo per particolari ad alta integritĂ prodottiin leghe primarie ma il risparmio dovuto alla riduzione del tempo ciclo, alla maggior durata degli stampie allâeliminazione totale dellâimpregnazione o quanto meno una sua drastica riduzione come di certe fasidella lavorazione meccanica, giustifica economicamente lâuso dellâSSR⢠con un tempo di ritornodellâinvestimento, in qualche caso inferiore ai 12 mesi
Commercial development of the semi-solid rheocasting (ssrtm) process
Rheocasting processes create non-dendritic, equiaxed microstructure suitable for semi-solid forming directly from liquid aluminum alloy. A new rheocasting technology that efficiently creates non-dendritic material was developed at the Massachusetts Institute of Technology in 2000 and discussed at the previous NADCA Congress in Cincinnati in 2001. In early 2002, Idra Casting Machines acquired the exclusive license from M.I.T. to develop and sell casting equipment utilizing the technology.Now known as Semi-Solid Rheocasting (SSRTM), the process has undergone development from the laboratory to a commercial machine. Designed as a retrofit for die casting machines, the rheocast machine allows die casters to not only increase part quality and make safety critical castings, but also to decrease cycle time and increase tool life. In this paper, the SSRTM station will be described in detail, and advantages of the process will be discussed
Uniqueness of the potential function for the vectorial Sturm-Liouville equation on a finite interval
[[abstract]]In this paper, the vectorial Sturm-Liouville operator L Q =âd 2 dx 2 +Q(x) is considered, where Q(x) is an integrable mĂm matrix-valued function defined on the interval [0,Ď] . The authors prove that m 2 +1 characteristic functions can determine the potential function of a vectorial Sturm-Liouville operator uniquely. In particular, if Q(x) is real symmetric, then m(m+1) 2 +1 characteristic functions can determine the potential function uniquely. Moreover, if only the spectral data of self-adjoint problems are considered, then m 2 +1 spectral data can determine Q(x) uniquely.[[notice]]čŁćŁĺŽç˘[[incitationindex]]SCI[[cooperationtype]]ĺĺ¤[[booktype]]éťĺ
Inverse spectral problems for Sturm-Liouville operators with singular potentials
The inverse spectral problem is solved for the class of Sturm-Liouville
operators with singular real-valued potentials from the space .
The potential is recovered via the eigenvalues and the corresponding norming
constants. The reconstruction algorithm is presented and its stability proved.
Also, the set of all possible spectral data is explicitly described and the
isospectral sets are characterized.Comment: Submitted to Inverse Problem
Inverse spectral problems for Sturm--Liouville operators with matrix-valued potentials
We give a complete description of the set of spectral data (eigenvalues and
specially introduced norming constants) for Sturm--Liouville operators on the
interval with matrix-valued potentials in the Sobolev space
and suggest an algorithm reconstructing the potential from the spectral data
that is based on Krein's accelerant method.Comment: 39 pages, uses iopart.cls, iopams.sty and setstack.sty by IO
Structure of the icosahedral Ti-Zr-Ni quasicrystal
The atomic structure of the icosahedral Ti-Zr-Ni quasicrystal is determined
by invoking similarities to periodic crystalline phases, diffraction data and
the results from ab initio calculations. The structure is modeled by
decorations of the canonical cell tiling geometry. The initial decoration model
is based on the structure of the Frank-Kasper phase W-TiZrNi, the 1/1
approximant structure of the quasicrystal. The decoration model is optimized
using a new method of structural analysis combining a least-squares refinement
of diffraction data with results from ab initio calculations. The resulting
structural model of icosahedral Ti-Zr-Ni is interpreted as a simple decoration
rule and structural details are discussed.Comment: 12 pages, 8 figure
Flavor-Specific Inclusive B Decays to Charm
We have measured the branching fractions for B -> D_bar X, B -> D X, and B ->
D_bar X \ell^+ \nu, where ``B'' is an average over B^0 and B^+, ``D'' is a sum
over D^0 and D^+, and``D_bar'' is a sum over D^0_bar and D^-. From these
results and some previously measured branching fractions, we obtain Br(b -> c
c_bar s) = (21.9 3.7)%, Br(b -> s g) K^-
\pi^+) = (3.69 0.20)%. Implications for the ``B semileptonic decay
problem'' (measured branching fraction being below theoretical expectations)
are discussed. The increase in the value of Br(b -> c c_bar s) due to eliminates 40% of the discrepancy.Comment: 12 page postscript file, postscript file also available through
http://w4.lns.cornell.edu/public/CLN
Measurement of using Partila Reconstruction of
We present a measurement of the absolute branching fraction for using the reconstruction of the decay chain , where only the lepton and the low-momentum pion from
the are detected. With data collected by the CLEO II detector at the
Cornell Electron Storage Ring, we have determined .Comment: 10 page postscript file, postscript file also available through
http://w4.lns.cornell.edu/public/CLN
- âŚ