25,075 research outputs found
Erratum: Luminosity function, sizes and FR dichotomy of radio-loud AGN
This erratum corrects a number of formulae containing mistakes in the paper
'Luminosity function, sizes and FR dichotomy of radio-loud AGN', 2007, MNRAS,
v. 381, p.1548. The corrections do not alter any of the conclusions in the
original paper.Comment: single page, no figures, erratum to MNRAS, 2007, v. 381, p. 154
Preparation of stable colloidal dispersions in fluorinated liquids
Chemical method for separating oil from water by liquid barrier which can be positioned magnetically is described. Fluorocarbon liquids containing colloidal suspension of magnetite is proposed. Chemical composition of magnetite and fluorinated ether polymer are presented
Research in the synthesis and characterization of magnetic fluids, phase 2 Quarterly report, Jan. - Mar. 1968
Ferrofluids prepared by grinding techniques and studied for viscosity and stability after fatty acid addition and magnetic field applicatio
Research in the synthesis and characterization of magnetic fluids, phase 2 Quarterly report, Jun. - Sep. 1967
Synthesis and characterization of colloids of thermally stable ferrofluids with higher magnetization and susceptibilit
Reducible chiral four-body interactions in nuclear matter
The method of unitary transformations generates five classes of leading-order
reducible chiral four-nucleon interactions which involve pion-exchanges and a
spin-spin contact-term. Their first-order contributions to the energy per
particle of isospin-symmetric nuclear matter and pure neutron matter are
evaluated in detail. For most of the closed four-loop diagrams the occurring
integrals over four Fermi-spheres can be reduced to easily manageable one- or
two-parameter integrals. One observes substantial cancelations among the
different contributions arising from 2-ring and 1-ring diagrams. Altogether,
the net attraction generated by the chiral four-nucleon interaction does not
exceed values of \,MeV for densities .Comment: 13 pages, 6 figures, submitted to European Physical Journal
Large N_c in chiral perturbation theory
The construction of the effective Lagrangian relevant for the mesonic sector
of QCD in the large N_c limit meets with a few rather subtle problems. We
thoroughly examine these and show that, if the variables of the effective
theory are chosen suitably, the known large N_c counting rules of QCD can
unambiguously be translated into corresponding counting rules for the effective
coupling constants. As an application, we demonstrate that the Kaplan-Manohar
transformation is in conflict with these rules and is suppressed to all orders
in 1/N_c. The anomalous dimension of the axial singlet current generates an
additional complication: The corresponding external field undergoes
nonmultiplicative renormalization. As a consequence, the Wess-Zumino-Witten
term, which accounts for the U(3)_R x U(3)_L anomalies in the framework of the
effective theory, contains pieces that depend on the running scale of QCD. The
effect only shows up at nonleading order in 1/N_c, but requires specific
unnatural parity contributions in the effective Lagrangian that restore
renormalization group invariance.Comment: 56 page
Making electromagnetic wavelets
Electromagnetic wavelets are constructed using scalar wavelets as
superpotentials, together with an appropriate polarization. It is shown that
oblate spheroidal antennas, which are ideal for their production and reception,
can be made by deforming and merging two branch cuts. This determines a unique
field on the interior of the spheroid which gives the boundary conditions for
the surface charge-current density necessary to radiate the wavelets. These
sources are computed, including the impulse response of the antenna.Comment: 29 pages, 4 figures; minor corrections and addition
Ferrofluid separator for nonferrous scrap separation
Behavior of nonmagnetic objects within separator is essentially function of density, and independent of size or shape of objects. Results show close agreement between density of object and apparent density of ferrofluid required to float it. Results also demonstrate that very high separation rates are achievable by ferrofluid sink-float separation
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