9,143 research outputs found
The Density Matrix Renormalization Group and the Nuclear Shell Model
We summarize recent efforts to develop an angular-momentum-conserving variant
of the Density Matrix Renormalization Group method into a practical truncation
strategy for large-scale shell model calculations of atomic nuclei. Following a
brief description of the key elements of the method, we report the results of
test calculations for Cr and Ni. In both cases we consider
nucleons limited to the 2p-1f shell and interacting via the KB3 interaction.
Both calculations produce a high level of agreement with the exact shell-model
results. Furthermore, and most importantly, the fraction of the complete space
required to achieve this high level of agreement goes down rapidly as the size
of the full space grows
Capture of manufacturing uncertainty in turbine blades through probabilistic techniques
Efficient designing of the turbine blades is critical to the performance of an aircraft engine.
An area of significant research interest is the capture of manufacturing uncertainty in the
shapes of these turbine blades. The available data used for estimation of this manufacturing
uncertainty inevitably contains the effects of measurement error/noise. In the present work,
we propose the application of Principal Component Analysis (PCA) for de-noising the
measurement data and quantifying the underlying manufacturing uncertainty. Once the
PCA is performed, a method for dimensionality reduction has been proposed which utilizes
prior information available on the variance of measurement error for different
measurement types. Numerical studies indicate that approximately 82% of the variation in
the measurements from their design values is accounted for by the manufacturing
uncertainty, while the remaining 18% variation is filtered out as measurement error
Density Matrix Renormalization Group study of Cr and Ni
We discuss the development of an angular-momentum-conserving variant of the
Density Matrix Renormalization Group (DMRG) method for use in large-scale
shell-model calculations of atomic nuclei and report a first application of the
method to the ground state of Ni and improved results for Cr. In
both cases, we see a high level of agreement with the exact results. A
comparison of the two shows a dramatic reduction in the fraction of the space
required to achieve accuracy as the size of the problem grows.Comment: 4 pages. Published in PRC Rapi
Aquacrops of Darbhanga District in north Bihar and their commercial significance
Darbhanga district in North Bihar is characterised by thick alluvial soil, moderately good rainfall, high humidity, ample sunshine and numerous water resources in the form of perennial rivers, tributaries, streams, lakes, ponds, pools and puddles. The aquacrops of this district include several species of commercially important fishes, aquatic cash crops such as makhana (Euryale ferox), singhara (Trapa spp.), lotus, lilly, Khubi etc. and molluscs. This paper highlights the commercial significance of these aquacrops and offers suggestions for their sustained development
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