1,273 research outputs found
Shearfree Condition and dynamical Instability in gravity
The implications of shearfree condition on instability range of anisotropic
fluid in are studied in this manuscript. A viable model is
chosen to arrive at stability criterion, where is Ricci scalar and is
the trace of energy momentum tensor. The evolution of spherical star is
explored by employing perturbation scheme on modified field equations and
contracted Bianchi identities in . The effect of imposed shearfree
condition on collapse equation and adiabatic index is studied in
Newtonian and post-Newtonian regimes.Comment: 16 page
A general purpose subroutine for fast fourier transform on a distributed memory parallel machine
One issue which is central in developing a general purpose Fast Fourier Transform (FFT) subroutine on a distributed memory parallel machine is the data distribution. It is possible that different users would like to use the FFT routine with different data distributions. Thus, there is a need to design FFT schemes on distributed memory parallel machines which can support a variety of data distributions. An FFT implementation on a distributed memory parallel machine which works for a number of data distributions commonly encountered in scientific applications is presented. The problem of rearranging the data after computing the FFT is also addressed. The performance of the implementation on a distributed memory parallel machine Intel iPSC/860 is evaluated
Size dependent magnetic and electrical properties of Ba-doped nanocrystalline BiFeO
Improvement in magnetic and electrical properties of multiferroic BiFeO
in conjunction with their dependence on particle size is crucial due to its
potential applications in multifunctional miniaturized devices. In this
investigation, we report a study on particle size dependent structural,
magnetic and electrical properties of sol-gel derived
BiBaFeO nanoparticles of different sizes ranging from
12 to 49 nm. The substitution of Bi by Ba significantly suppresses
oxygen vacancies, reduces leakage current density and Fe state. An
improvement in both magnetic and electrical properties is observed for 10 %
Ba-doped BiFeO nanoparticles compared to its undoped counterpart. The
saturation magnetization of BiBaFeO nanoparticles increase
with reducing particle size in contrast with a decreasing trend of
ferroelectric polarization. Moreover, a first order metamagnetic transition is
noticed for 49 nm BiBaFeO nanoparticles which
disappeared with decreasing particle size. The observed strong size dependent
multiferroic properties are attributed to the complex interaction between
vacancy induced crystallographic defects, multiple valence states of Fe,
uncompensated surface spins, crystallographic distortion and suppression of
spiral spin cycloid of BiFeO.Comment:
Eksistensi Akad dalam Transaksi Keuangan Syariah
This paper will explore the existence of the contract has a crucial role in Islamic financial transactions with a number of implications posed. One of that in Islam there is freedom to determine the contract with all the terms and forms of contract desired by the parties, provided that the contract is voluntary and is not included in the prohibition of sharia\u27. On this basis, the core of the contract which is carried out in Islam is to create benefits for the parties to the agreement for an Islamic financial transactions
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Modulation of Sri Lankan Maha rainfall by the Indian Ocean Dipole
Investigating the September to December rainy season in Sri Lanka associated with the Maha rice growing season provides insights into the Asian monsoon during the boreal fall. Here, the modulation of the Maha rainfall by the tropical air-sea coupled phenomenon referred to as the Indian Ocean Dipole (IOD) is documented. The Maha rainfall has a strong and robust association with the IOD from 1869 to 2000. The anomalously warm sea surface in the western Indian Ocean associated with the positive IOD phase induces large scale convergence in the lower troposphere extending to Sri Lanka leading to the preponderant enhancement of Maha rainfall
Ewald methods for inverse power-law interactions in tridimensional and quasi-two dimensional systems
In this paper, we derive the Ewald method for inverse power-law interactions
in quasi-two dimensional systems. The derivation is done by using two different
analytical methods. The first uses the Parry's limit, that considers the Ewald
methods for quasi-two dimensional systems as a limit of the Ewald methods for
tridimensional systems, the second uses Poisson-Jacobi identities for lattice
sums. Taking into account the equivalence of both derivations, we obtain a new
analytical Fourier transform intregral involving incomplete gamma function.
Energies of the generalized restrictive primitive model of electrolytes
(-RPM) and of the generalized one component plasma model (-OCP) are
given for the tridimensional, quasi-two dimensional and monolayers systems. Few
numerical results, using Monte-Carlo simulations, for -RPM and -OCP
monolayers systems are reported.Comment: to be published in Journal of Physics A: Mathematical and Theoretical
(19 pages, 2 figures and 3 tables
Coliform Distribution Around The Antang Landfill Soil Makassar City, South Sulawesi
Tamangapa Antang landfill in its operation was conducted by open dumping, which potentially contaminate the surrounding soil. Research has been conducted on the distribution of Coliform bacteria as soil contaminants around Antang Landfill in Makassar City. This research aimed to determine to what extent the distribution of Coliform bacteria contaminate the soil around Antang Landfill. The sampling was divided into 4 Lines, 2 Lines were in the direction of the groundwater flow (Line A and Line C) and 2 Lines were perpendicular to the groundwater flow (Line B and Line D), at the depth of 0 to 10 cm, 10 to 20 cm and 20 to 30 cm. Samples were analyzed using Nutrient Agar and Biochemical Test method. The results show that Coliform Bacteria have spread vertically on Topsoil. The highest abundance population of Coliform bacteria was detected in Line B (240 cfu/gr) at 10 to 20 cm depth, Line D (210 cfu/gr) at 0 to 10 cm depth, Line A (110 cfu/gr) at 10 to 20 cm depth and Line B (23 cfu/gr) at 0 to 10 cm depth. The abundance of Coliform bacteria in the soil is very potential to contaminate the bio-soil environment, plants, damage the soil surface and structure around the Antang Landfill
Controlled access to cloud resources for mitigating economic denial of sustainability (EDoS) attacks
Cloud computing is a paradigm that provides scalable IT resources as a service over the Internet. Vulnerabilities in the cloud infrastructure have been readily exploited by the adversary class. Therefore, providing the desired level of assurance to all stakeholders through safeguarding data (sensitive or otherwise) which is stored in the cloud, is of utmost importance. In addition, protecting the cloud from adversarial attacks of diverse types and intents, cannot be understated. Economic Denial of Sustainability (EDoS) attack is considered as one of the concerns that has stalled many organizations from migrating their operations and/or data to the cloud. This is because an EDoS attack targets the financial component of the service provider. In this work, we propose a novel and reactive approach based on a rate limit technique, with low overhead, to detect and mitigate EDoS attacks against cloud-based services. Through this reactive scheme, a limited access permission for cloud services is granted to each user. Experiments were conducted in a laboratory cloud setup, to evaluate the performance of the proposed mitigation technique. Results obtained show that the proposed approach is able to detect and prevent such an attack with low cost and overhead. © 2016 Elsevier B.V. All rights reserved
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