5,791 research outputs found
Chimera states: The Existence Criteria Revisited
Chimera states, representing a spontaneous break-up of a population of
identical oscillators that are identically coupled, into sub-populations
displaying synchronized and desynchronized behavior, have traditionally been
found to exist in weakly coupled systems and with some form of nonlocal
coupling between the oscillators. Here we show that neither the weak-coupling
approximation nor nonlocal coupling are essential conditions for their
existence. We obtain for the first time amplitude-mediated chimera states in a
system of globally coupled complex Ginzburg-Landau oscillators. We delineate
the dynamical origins for the formation of such states from a bifurcation
analysis of a reduced model equation and also discuss the practical
implications of our discovery of this broader class of chimera states.Comment: 5 pages, 5 figure
Study of fragmentation and momentum correlations in heavy-ion collisions
The role of momentum correlations is studied in the production of light and
medium mass fragments by imposing momentum cut in clusterization the phase
space. Our detailed investigation shows that momentum cut has major role to
play in the emission of fragments.Comment: 16 pages, 7 figure
Stability of networks of delay-coupled delay oscillators
Dynamical networks with time delays can pose a considerable challenge for
mathematical analysis. Here, we extend the approach of generalized modeling to
investigate the stability of large networks of delay-coupled delay oscillators.
When the local dynamical stability of the network is plotted as a function of
the two delays then a pattern of tongues is revealed. Exploiting a link between
structure and dynamics, we identify conditions under which perturbations of the
topology have a strong impact on the stability. If these critical regions are
avoided the local stability of large random networks can be well approximated
analytically
CP Violation and Flavour Mixings in Orbifold GUTs
We address the flavour problem by incorporating the hypothesis of universal
strength of Yukawa couplings in the framework of a 5D GUT model compactified on
an orbifold. We show that a quantitatively
successful picture of fermion masses and mixings emerges from the interplay
between the bulk suppression factors of geometric origin and the phases of the
Yukawa matrices. We give an explicit example, where we obtain a good fit for
both the CKM and PMNS matrices.Comment: 8 pages, no figures; v2: minor changes, published in Phys Rev D
(Rapid Communication
On the Balance of Intercalation and Conversion Reactions in Battery Cathodes
We present a thermodynamic analysis of the driving forces for intercalation
and conversion reactions in battery cathodes across a range of possible working
ion, transition metal, and anion chemistries. Using this body of results, we
analyze the importance of polymorph selection as well as chemical composition
on the ability of a host cathode to support intercalation reactions. We find
that the accessibility of high energy charged polymorphs in oxides generally
leads to larger intercalation voltages favoring intercalation reactions,
whereas sulfides and selenides tend to favor conversion reactions. Furthermore,
we observe that Cr-containing cathodes favor intercalation more strongly than
those with other transition metals. Finally, we conclude that two-electron
reduction of transition metals (as is possible with the intercalation of a
ion) will favor conversion reactions in the compositions we studied
Operation of Induction Motor Open-delta Transformer Banks
Induction motors and transformers are among the earliest electrical equipment to be manufactured. The squirrel-cage induction motor has been studied very widely from the time of Tesla and Ferraris in 1889. The operation of a squirrel-cage induction motor with an unbalanced supply voltage has also been studied in great detail. Yet there is little mention of an induction motor operating on an open-delta or vee-connected transformer bank in textbooks. The open-delta transformer connection is the equivalent of the delta-delta connection with one transformer removed. The vee-connection is equivalent to a star-delta connection with one transformer removed; the primary neutral must be connected. However, both of these connections behave identically as far as the output is concerned. Hence, as a general term open-delta will be used throughout the discussion. Open-delta connections are used in emergencies where one of a group of three delta-delta connected transformers becomes defective and has to be removed from service. The remaining two transformers transmit three-phase power with a reduced load capacity. Such connections are also used in areas where the load is expected to increase. A third transformer can be readily added converting the open-delta to a delta-delta or wye-delta, thereby increasing the load ca pa city. Open-delta transformer banks are quite commonly used by rural electric co-operatives. It is cheaper to install an open-wye open-delta bank. The loads are often house-hold loads, small motors, and seasonal pumps; the slight unbalance introduced due to an open-delta secondary is usually not serious. Open-delta transformer banks, as can be seen, are used to supply three-phase induction motors. However, due to the lack of sufficient published works and detailed studies, there may be a substantial waste in transformers and/or motor capacity. The author, therefore, chose to investigate the development of an equivalent circuit for an induction motor supplied by an open-delta transformer bank, and to study the performance of the induction motor. Finally, a family of curves was developed for easy evaluation of the voltage unbalance factor. Unbalance factor plays an important part in determining the performance of the motor operating under unbalanced voltage conditions. Unbalance factor is defined as the ratio of the negative to positive-sequence voltage
Draft genome sequence of the naturally competent Bacillus simplex strain WY10
ABSTRACT
We sequenced a naturally competent bacterial isolate, WY10, cultured from a Wyoming soil sample. Sequence analysis revealed that WY10 is a novel strain of
Bacillus simplex
. To our knowledge, WY10 is the first
B. simplex
strain to be characterized as naturally competent for DNA uptake by transformation.
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Mistakes, Miscalculations and the Search for Middle Ground: An Exit Strategy for Nepal
Although he may have had good intentions, King Gyanendra miscalculated the effect of his draconian measures on February 1, 2005. The King and his advisors miscalculated the capacity of the military, the response from the international community, the effectiveness of loyalists, the appeal to Hindus, the role of China, as well as attitudes towards corruption and censorship. In order to return to a democratic path, a path that is also the only viable option for the survival of the constitutional monarchy, Nepals three political protagonists — the King, the Maoists, and the political parties — must compromise. An exit strategy is possible, but it requires that these three protagonists put the interests of Nepal above their own narrow, parochial interests.\u2
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