19,117 research outputs found
A Novel Jet Model: Magnetically Collimated, Radiation-Pressure Driven Jet
Relativistic jets from compact objects are ubiquitous phenomena in the
Unvierse, but their driving mechanism has been an enigmatic issue over many
decades. Two basic models have been extensively discussed: magnetohydrodynamic
(MHD) jets and radiation-hydrodynamic (RHD) jets. Currently, the former is more
widely accepted, since magnetic field is expected to provide both the
acceleration and collimation mechanisms, whereas radiation field cannot
collimate outflow. Here, we propose a new type of jets,
radiation-magnetohydrodynamic (RMHD) jets, based on our global RMHD simulation
of luminous accretion flow onto a black hole shining above the Eddington
luminosity. The RMHD jet can be accelerated up to the relativistic speed by the
radiation-pressure force and is collimated by the Lorentz force of a magnetic
tower, inflated magnetic structure made by toroidal magnetic field lines
accumulated around the black hole, though radiation energy greatly dominates
over magnetic energy. This magnetic tower is collimated by a geometrically
thick accretion flow supported by radiation-pressure force. This type of jet
may explain relativistic jets from Galactic microquasars, appearing at high
luminosities.Comment: 5 pages, 2 figures, accepted for publication in PAS
Manufacture and evaluation of Li/BCX DD cells
This project is divided into four main tasks: cell manufacture, acceptance, and lot certification of cells, performance testing of cells, and abuse testing of cells. Lithium/bromine chloride in thionyl chloride (Li/BCX) 149 DD cells (PN 3B2085-XA) were built according to the provisions of Electrochem Industries Quality Plan 17096. Acceptance and lot certification testing was performed according to NASA JSC Document EP5-83-025, Revision B. Acceptance testing included open circuit and load voltage check, visual examination, size and weight measurements, and high temperature exposure. Lot certification tests were performed for capacity performance and for performance under conditions of thermal and electrical abuse. These tests included 149 C exposure, capacity discharge, fuse check, high temperature exposure, high rate discharge, short circuit, vibration, and overdischarge testing. A quantity of 200 cells was delivered to Johnson Space Center for life test evaluation. A parametric evaluation of the capacity discharge of Li/BCX DD cells was performed over a variety of temperatures and discharge rates. This testing served to map the performance capability of the cell. Tests were also performed over a variety of electrical and thermal abuse conditions. Abuse tests included short circuit, charging, overdischarge, high temperature exposure, shock, and vibration
Distribution of Snow and Maximum Snow Water Equivalent Obtained by LANDSAT Data and Degree Day Method
Maximum snow water equivalence and snowcover distribution are estimated using several LANDSAT data taken in snowmelting season over a four year period. The test site is Okutadami-gawa Basin located in the central position of Tohoku-Kanto-Chubu District. The year to year normalization for snowmelt volume computation on the snow line is conducted by year to year correction of degree days using the snowcover percentage within the test basin obtained from LANDSAT data. The maximum snow water equivalent map in the test basin is generated based on the normalized snowmelt volume on the snow line extracted from four LANDSAT data taken in a different year. The snowcover distribution on an arbitrary day in snowmelting of 1982 is estimated from the maximum snow water equivalent map. The estimated snowcover is compared with the snowcover area extracted from NOAA-AVHRR data taken on the same day. The applicability of the snow estimation using LANDSAT data is discussed
Morita equivalences induced by bimodules over Hopf-Galois extensions
Let be a Hopf algebra, and be -Galois extensions. We investigate
the category of relative Hopf bimodules, and the Morita
equivalences between and induced by them.Comment: 32 page
Quantum phase gate for photonic qubits using only beam splitters and post-selection
We show that a beam splitter of reflectivity one-third can be used to realize
a quantum phase gate operation if only the outputs conserving the number of
photons on each side are post-selected.Comment: 6 pages RevTex, including one figur
CP,T and/or CPT Violations in the K0-K0bar System --Implications of the KTeV,NA48 and CPLEAR Results
Possible violation of CP, T and/or CPT symmetries in the \ko-\kob system
is studied from a phenomenological point of view. For this purpose, we first
introduce parameters which represent violation of these symmetries in mixing
parameters and decay amplitudes in a convenient and well-defined way and,
treating these parameters as small, derive formulas which relate them to the
experimentally measured quantities. We then perform numerical analyses, with
the aid of the Bell-Steinberger relation, to derive constraints to these
symmetry-violating parameters, firstly paying particular attention to the
results reported by KTeV Collaboration and NA48 Collaboration, and then with
the results reported by CPLEAR Collaboration as well taken into account. A case
study, in which either CPT symmetry or T symmetry is assumed, is also carried
out. It is demonstrated that CP and T symmetries are violated definitively at
the level of 10^{-4} in decays and presumably at the level of 10^{-3} in
the \ko-\kob mixing, and that the Bell-Steinberger relation helps us to
establish CP and T violations being definitively present in the \ko-\kob
mixing and to test CPT symmetry to a level of 10^{-4} ~ 10^{-5}.Comment: 21 pages, 1 figure
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