12,549 research outputs found
Local cosmic string and C-field
We investigate a local cosmic string with a phenomenological energy momentum
tensor as prescribed by Vilenkin, in presence of C-field . The solutions of
full nonlinear Einstein's equations for exterior and interior regions of such a
string are presented.Comment: 7 page
Digital quantum simulation of spin models with circuit quantum electrodynamics
Systems of interacting quantum spins show a rich spectrum of quantum phases
and display interesting many-body dynamics. Computing characteristics of even
small systems on conventional computers poses significant challenges. A quantum
simulator has the potential to outperform standard computers in calculating the
evolution of complex quantum systems. Here, we perform a digital quantum
simulation of the paradigmatic Heisenberg and Ising interacting spin models
using a two transmon-qubit circuit quantum electrodynamics setup. We make use
of the exchange interaction naturally present in the simulator to construct a
digital decomposition of the model-specific evolution and extract its full
dynamics. This approach is universal and efficient, employing only resources
which are polynomial in the number of spins and indicates a path towards the
controlled simulation of general spin dynamics in superconducting qubit
platforms.Comment: 12 pages, 9 figure
Electric field driven destabilization of the insulating state in nominally pure LaMnO3
We report an electric field driven destabilization of the insulating state in
nominally pure LaMnO3 single crystal with a moderate field which leads to a
resistive state transition below 300 K. The transition is between the
insulating state in LaMnO3 and a high resistance bad metallic state that has a
temperature independent resistivity. The transition occurs at a threshold field
(Eth) which shows a steep enhancement on cooling. While at lower temperatures
the transition is sharp and involves large change in resistance but it softens
on heating and eventually absent above 280K. When the Mn4+ content is increased
by Sr substitution up to x=0.1, the observed transition though observable in
certain temperature range, softens considerably. The observation has been
explained as bias driven percolation type transition between two coexisting
phases, where the majority phase is a charge and orbitally ordered polaronic
insulating phase and the minority phase is a bad metallic phase. The mobile
fraction f of the bad metallic phase deduced from the experimental data follows
an activated kinetics with the activation energy nearly equal to 200 meV and
the prefactor fo is a strong function of the field that leads to a rapid
enhancement of f on application of field leading to the resistive state
transition. We suggest likely scenarios for such co-existing phases in
nominally pure LaMnO3 that can lead to the bias driven percolation type
transition.Comment: Accepted in JPC
On Upward Drawings of Trees on a Given Grid
Computing a minimum-area planar straight-line drawing of a graph is known to
be NP-hard for planar graphs, even when restricted to outerplanar graphs.
However, the complexity question is open for trees. Only a few hardness results
are known for straight-line drawings of trees under various restrictions such
as edge length or slope constraints. On the other hand, there exist
polynomial-time algorithms for computing minimum-width (resp., minimum-height)
upward drawings of trees, where the height (resp., width) is unbounded.
In this paper we take a major step in understanding the complexity of the
area minimization problem for strictly-upward drawings of trees, which is one
of the most common styles for drawing rooted trees. We prove that given a
rooted tree and a grid, it is NP-hard to decide whether
admits a strictly-upward (unordered) drawing in the given grid.Comment: Appears in the Proceedings of the 25th International Symposium on
Graph Drawing and Network Visualization (GD 2017
ISTRAŽIVANJE GENETSKE RAZNOLIKOSTI U UZGOJU KRUMPIRA
With a view to select divergent parents genetic diversity was estimated among twenty genotypes. Thirty F1 progenies developed by line-tester mating were studied from seedling generation to first clonal generation for five important agronomic traits. Cluster analysis reveals that the parents could be grouped into seven different clusters. Cluster means showed wide range of variation for several traits among singles as well as multi genotypic clusters. Considering diversity pattern, parents should select from cluster I, III, IV and V for the improvement of potato. Analysis of variance revealed that all most all the sources of variation were highly significant for all the studied traits in both generations. Parents Challisha, Lalpakri, Patnai, Chamak, Sadagoti, TPS-67 and TPS-364 were found to be good general combiners for tuber yield and yield contribution traits due to their gca effects. The sca effects showed that out of 30 hybrids 12 were found to have specific combining ability for tuber yield and those hybrids also exhibited considerable heterosis for tuber yield and yield contributing traits.U svrhu selekcije različitih roditelja procijenjena je genetska raznolikost među dvadeset genotipova. Trideset potomaka F1 razvijenih spajanjem linija - ispitivača istraživano je od generacije sadnica do prve generacije klona za pet važnih agronomskih osobina. Analizom klastera otkriveno je da se roditelji mogu svrstati u sedam različitih klastera. Prosjeci klustera pokazali su veliki raspon variranja kod nekoliko osobina među pojedinačnim kao i višegenotipskim klasterima. S obzirom na raznolikost uzorka roditelje treba selekcionirati iz klastera I, III, IV i V za oplemenjivanje krumpira. Analizom varijance otkriveno je da su gotovo svi izvori variranja bili veoma značajni za sve istraživane osobine u obje generacije. Roditelji Challisha, Lalpakri, Patnai, Chamak, Sadagoti, TPS-67 i TPS-364 bili su dobri spajatelji za prinos gomolja i osobine prinosa zbog svog gca djelovanja. Djelovanje gca je pokazalo da je od 30 hibrida 12 imalo određene sposobnosti spajanja za prinos gomolja, a ti su hibridi također ispoljili znatnu heterozu za osobine prinosa gomolja i osobine što doprinose prinosu
Review on composite cation exchanger as interdicipilinary materials in analytical chemistry
Green chemistry and technology is the design of chemical manufacturing systems to minimize their adverse affects on the environment. Thus, a primary goal of green chemistry and technology is to reduce the environmental impact of chemical processes and chemical manufacturing while simultaneously enhancing the overall process performance. Although it is beneficial to simply reduce the use of organic solvents in chemical processes, green chemistry and technology goes further, in that it evaluates the entire thing to identify techniques that can be applied to minimize the overall process hazard, while maintaining economic practicality. Evaluation of the environmental impacts of the manufacturing process requires a systematic approach and appropriate metrics that permit quantitative assessment of environmental hazards. Thus, this review begins with a introduction of cation-exchange materials the drivers for green technology and the metrics through which processes can be started. Then, the cation-exchange materials have so many applications described in this review and their many derivative and we describes inorganic to nanocomposite cation exchange materials and their technological improvement from old era to latest age of nano because green chemistry can be applied to real processes. Two elements are specifically highlighted: (a) the use of new materials to facilitate active and selective chemistry and the use of said materials within removal of environment hazardous
Automotive applications of thermoplastic vulcanizates
Thermoplastic vulcanizates (TPVs) are special classes of thermoplastic elastomers, in which dynamic vulcanization of the rubber phase takes place during melt mixing with a semicrystalline thermoplastic matrix phase at elevated temperature. This review article focus on the different types of thermoplastic vulcanizates (TPVs) from various elastomer and thermoplastic blends that are suitable for the automotive applications purpose. A detailed study of the various TPVs based on polypropylene-ethylene propylene diene rubber (PP-EPDM) and polypropylene-ethylene α-olefin has been focused and their application in the automobile sector has been summarized. Most of the commercially available TPVs are PP-EPDM based. Limited applications of that TPVs in high heat and oil resistant application purposes requires new generation of TPVs. High performance TPVs or super TPVs are new generation TPVs that exhibit high heat resistance as well as excellent oil resistance property suitable for automotive under-the-hood applications. Therefore TPVs based on XNBR-PA12, HNBR-PA12 and FKM-PA6 system has also been explored in details in this study and the possibility of the use of those TPV system has been focused for the high temperature application purpose in the automobile sector where high and oil resistant application properties is the prime concern
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