961 research outputs found
Geodesic motions in extraordinary string geometry
The geodesic properties of the extraordinary vacuum string solution in (4+1)
dimensions are analyzed by using Hamilton-Jacobi method. The geodesic motions
show distinct properties from those of the static one. Especially, any freely
falling particle can not arrive at the horizon or singularity. There exist
stable null circular orbits and bouncing timelike and null geodesics. To get
into the horizon {or singularity}, a particle need to follow a non-geodesic
trajectory. We also analyze the orbit precession to show that the precession
angle has distinct features for each geometry such as naked singularity, black
string, and wormhole.Comment: 15 pages, 11 figure
Efficient recovery of nitrate from municipal wastewater via MCDI using anion-exchange polymer coated electrode embedded with nitrate selective resin
Counteracting Selfish Nodes Using Reputation Based System in Mobile Ad Hoc Networks
A mobile ad hoc network (MANET) is a group of nodes constituting a network of mobile nodes without predefined and pre-established architecture where mobile nodes can communicate without any dedicated access points or base stations. In MANETs, a node may act as a host as well as a router. Nodes in the network can send and receive packets through intermediate nodes. However, the existence of malicious and selfish nodes in MANETs severely degrades network performance. The identification of such nodes in the network and their isolation from the network is a challenging problem. Therefore, in this paper, a simple reputation-based scheme is proposed which uses the consumption and contribution information for selfish node detection and cooperation enforcement. Nodes failing to cooperate are detached from the network to save resources of other nodes with good reputation. The simulation results show that our proposed scheme outperforms the benchmark scheme in terms of NRL (normalized routing load), PDF (packet delivery fraction), and packet drop in the presence of malicious and selfish attacks. Furthermore, our scheme identifies the selfish nodes quickly and accurately as compared to the benchmark scheme
Creation of a black hole pair with a domain wall
We study the creation of a black hole (BH) pair separated by a domain wall,
in the presence of a cosmological constant. We construct the solution
representing a BH pair with a domain wall and compute the Euclidean action to
evaluate the probability of the pair creation in the background with a
preexisting domain wall. The BHs can be either neutral or magnetically charged
ones. We compare the results of the charged case with those of the neutral case
with the same cosmological constant. We find that the production rate of a
charged BH pair is always suppressed in comparison with that of the neutral one
in both four and five dimensions, irrespective of the sign of the cosmological
constant. The Euclidean action is equal to the minus of the entropy. Since the
horizon area of a BH is decreased as the magnitude of its charge is increased
in general, the decreasing creation rate can be understood in terms of the
increasing charge. We obtain the explicit confirmation on the relation between
the pair creation rate of the charged BHs and the area of horizons in both the
four- and five-dimensional cases in the presence of a cosmological constant.
The singularity of the domain wall universe with charged BHs, as distinct from
that with neutral BHs, can be avoided.Comment: 23 pages, 11 figures, Some typos corrected and references added with
respect to the published versio
Production and optical properties of liquid scintillator for the JSNS experiment
The JSNS (J-PARC Sterile Neutrino Search at J-PARC Spallation Neutron
Source) experiment will search for neutrino oscillations over a 24 m short
baseline at J-PARC. The JSNS inner detector will be filled with 17 tons
of gadolinium-loaded liquid scintillator (LS) with an additional 31 tons of
unloaded LS in the intermediate -catcher and outer veto volumes.
JSNS has chosen Linear Alkyl Benzene (LAB) as an organic solvent because
of its chemical properties. The unloaded LS was produced at a refurbished
facility, originally used for scintillator production by the RENO experiment.
JSNS plans to use ISO tanks for the storage and transportation of the LS.
In this paper, we describe the LS production, and present measurements of its
optical properties and long term stability. Our measurements show that storing
the LS in ISO tanks does not result in degradation of its optical properties.Comment: 7 pages, 4 figures
Moduli Dynamics of AdS_3 Strings
We construct a general class of solutions for a classical string in AdS_3
spacetime. The construction is based on a Pohlmeyer type reduction, with the
sinh-Gordon model providing the general N-soliton solutions. The corresponding
exact spiky string configurations are then reconstructed through the inverse
scattering method. It is shown that the string moduli are determined entirely
by those of the solitons.Comment: 22 pages, no figures; references adde
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