2,414 research outputs found
Spherical Tuples of Hilbert Space Operators
We introduce and study a class of operator tuples in complex Hilbert spaces,
which we call spherical tuples. In particular, we characterize spherical
multi-shifts, and more generally, multiplication tuples on RKHS. We further use
these characterizations to describe various spectral parts including the Taylor
spectrum. We also find a criterion for the Schatten -class membership of
cross-commutators of spherical -shifts. We show, in particular, that
cross-commutators of non-compact spherical -shifts cannot belong to
for .
We specialize our results to some well-studied classes of multi-shifts. We
prove that the cross-commutators of a spherical joint -shift, which is a
-isometry or a -expansion, belongs to if and only if . We
further give an example of a spherical jointly hyponormal -shift, for which
the cross-commutators are compact but not in for any .Comment: a version close to final on
A Novel Fault Tolerant Full Bridge DC/DC Converter for Photovoltaic application
Abstract: Power switches in converters are prone to open and short circuit faults. Faulty power switch in converters worsens the converter performance and it may result in failure of other devices also. Further when main power switch fails, it results in breakdown of entire system. Therefore for reliability improvement of full bridge DC/DC converter in PV system, this research paper presents a novel fault tolerant converter topology for exact faulty power switch localization and isolation from main path so that redundant faulty power switch can be brought in action and still system will provide desired output power. The converter presented here need two redundant power switches and relays to provide fault tolerant competence. It has four operating states which are normal state, faulty state, fault diagnostic state and fault recovery state. In the technique presented here RMS current at given test points is computed and compared with threshold RMS current for determination of faulty power switch. Graph theory is used to show the topological equivalence of converter in normal and fault recovery states. Simulation and experimental results have shown that converter efficiency remains same in both normal and fault recovery state
Proximate analysis and mineral characterization of Barringtonia species
The study about material contained in Barringtonia seeds were conducted at the first time using the standard procedure of AOAC. For present work, two species of Barringtonia were selected viz., B. acutangula and B. racemosa . The proximate composition and mineral constituents of Barringtonia seeds were evaluated. The B. acutangula seeds contained ash 4.24%, crude protein 9.23%, crude lipids 0.68%, crude fibre13.54% and carbohydrates 66.17%. While in seeds of B. racemosa, ash 4.02%, crude protein 12.09%, crude lipids 0.75%, crude fibre15.18% and carbohydrates: 64.67% were observed. Both the species have a high energy value on dry basis. Comparing the mineral content with recommended dietary allowances (RDA), the results indicated that seeds of B. acutangula fruits could be a good supplement for some nutrients such as calcium, fibre and carbohydrates, whereas the B. racemosa seeds could be a good supplement for some nutrients such as fibre, potassium, zinc and carbohydrates. The seeds of Barringtonia could be promoted as a carbohydrate supplement. Hence, this piece of work acclaims the potential of Barringtonia species indicating its proximate and mineral composition
Copper(I) complexes with N-(2-quinolinylmethylene)-1, 5-dimethyl- 2-phenyl-1-pyrazole-3-(2H)-one and phosphine as ligands: Effective catalyst for Sonogashira cross-coupling reaction
598-607A new series of copper(I) complexes of the type [Cu(L)(PPh3)2]X (1a-c) and [Cu(L)(dppe)]X (2a-c) have been prepared by the reaction of Cu(MeCN)4]X (where X = ClO, BF and PF) with N-(2-quinolinylmethylene)-1,5-dimethyl-2-phenyl-1-pyrazole-3-(2H)-one (L) in presence of triphenylphosphine (PPh3) or 1,2-bis(diphenylphosphino)ethane (dppe) as an ancillary ligand. The UV-visible spectra indicate that, the ancillary phosphine ligands significantly perturb the MLCT state of copper(I) complexes. The thermally stable 1a-c and 2a-c complexes exhibit quasireversible redox behaviour corresponding to Cu(I)/Cu(II) couple. All complexes are tested as catalyst for Sonogashira cross-coupling of phenylacetylene with aryl iodide. The results show that all complexes worked as an effective catalyst at low temperature yielding substituted aryl alkynes as a product. The nature of phosphine ligands and size of counter anions shows marked effect on catalytic properties of all the complexes
Program Transformations for Asynchronous and Batched Query Submission
The performance of database/Web-service backed applications can be
significantly improved by asynchronous submission of queries/requests well
ahead of the point where the results are needed, so that results are likely to
have been fetched already when they are actually needed. However, manually
writing applications to exploit asynchronous query submission is tedious and
error-prone. In this paper we address the issue of automatically transforming a
program written assuming synchronous query submission, to one that exploits
asynchronous query submission. Our program transformation method is based on
data flow analysis and is framed as a set of transformation rules. Our rules
can handle query executions within loops, unlike some of the earlier work in
this area. We also present a novel approach that, at runtime, can combine
multiple asynchronous requests into batches, thereby achieving the benefits of
batching in addition to that of asynchronous submission. We have built a tool
that implements our transformation techniques on Java programs that use JDBC
calls; our tool can be extended to handle Web service calls. We have carried
out a detailed experimental study on several real-life applications, which
shows the effectiveness of the proposed rewrite techniques, both in terms of
their applicability and the performance gains achieved.Comment: 14 page
A Critical Review of Katishoola in Ayurvedic Science
Kati Shoola is one of the Vataja Nanatamaja Vikara explained by Acharya Charaka. Kati Shoola noticed in females and young population. Kati Shoola is not a harmful disease but it effects a large population. In primary stages it will subside with the basic therapies, folklore medicine and along with the bed rest
Subdued Voices: Women Characters and their Author in Inside the Haveli
Rama Mehta is an eminent novelist who contributed significantly to Indian English fiction by bringing female issues to the fore through her exemplary novel, Inside the Haveli. The novel shows a predominant concern with the subjugating condition of women characters shackled in the Indian patriarchal structure and brings, particularly, into light the repressed state of female characters and the elements that determine their submission. Simultaneously, based on the incident, the novel reveals silence and submission on the part of the novelist as well. Nevertheless, the work seems stifled when dealing with women's issues; its movements are confusing, contradicting and oscillating. The characters and their author appear tense under pressure showing a disinclination to adopt a bold stance. This cramped and oscillating situation speaks of their helplessness and repressed situation
Influence of Waterlogging on Carbohydrate Metabolism in Ragi and Rice Roots
Effect of different durations of waterlogging (4, 8 and 12 days) stress on carbohydrate status and activities of some related enzymes in ragi and rice roots was studied. In both ragi and rice roots there was decrease in starch and total sugar content in response to waterlogging conditions. Activity of α amylase was decrease in ragi roots while opposite trend was noticed in case of rice roots. The activity of pyruvate kinase was markedly increased due to 4, 8 and 12 days waterlogging in ragi roots while such increase was noticed in rice roots due to 12 days stress. Treatment of waterlogging caused enhancement in the activity of alkaline inorganic pyrophosphatase in the roots of both ragi and rice
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