16,233 research outputs found
Coil ignition
Coil Ignition 1. â˘
Magneto Ignition 32. â˘
Automobile Electric Starting and Lighting apparatus 67. â˘
Appendix 90. â˘
Appended are also copies of 4 patent
specifications and 7 Applications for
Patents
Tradeoff between short-term and long-term adaptation in a changing environment
We investigate the competition dynamics of two microbial or viral strains
that live in an environment that switches periodically between two states. One
of the strains is adapted to the long-term environment, but pays a short-term
cost, while the other is adapted to the short-term environment and pays a cost
in the long term. We explore the tradeoff between these alternative strategies
in extensive numerical simulations, and present a simple analytic model that
can predict the outcome of these competitions as a function of the mutation
rate and the time scale of the environmental changes. Our model is relevant for
arboviruses, which alternate between different host species on a regular basis.Comment: 9 pages, 3 figures, PRE in pres
Disorder-induced microscopic magnetic memory
Using coherent x-ray speckle metrology, we have measured the influence of
disorder on major loop return point memory (RPM) and complementary point memory
(CPM) for a series of perpendicular anisotropy Co/Pt multilayer films. In the
low disorder limit, the domain structures show no memory with field cycling--no
RPM and no CPM. With increasing disorder, we observe the onset and the
saturation of both the RPM and the CPM. These results provide the first direct
ensemble-sensitive experimental study of the effects of varying disorder on
microscopic magnetic memory and are compared against the predictions of
existing theories.Comment: 4 pages, 4 figures. Accepted for publication in Physical Review
Letters in Nov. 200
SIMBOL-X : a new generation hard X-ray telescope
SIMBOL-X is a hard X-ray mission, operating in the 0.5-70 keV range, which is
proposed by a consortium of European laboratories for a launch around 2010.
Relying on two spacecraft in a formation flying configuration, SIMBOL-X uses a
30 m focal length X-ray mirror to achieve an unprecedented angular resolution
(30 arcsec HEW) and sensitivity (100 times better than INTEGRAL below 50 keV)
in the hard X-ray range. SIMBOL-X will allow to elucidate fundamental questions
in high energy astrophysics, such as the physics of accretion onto Black Holes,
of acceleration in quasar jets and in supernovae remnants, or the nature of the
hard X-ray diffuse emission. The scientific objectives and the baseline
concepts of the mission and hardware design are presented.Comment: 12 pages, 16 fig., Proc. SPIE conf. 5168, San Diego, Aug. 200
X-ray observations of the compact central object in supernova remnant G347.3-0.5
We present Chandra, XMM-Newton and RXTE observations of 1WGA J1713.4-3949, a
compact source at the center of the galactic supernova remnant (SNR)
G347.3-0.5. The X-ray spectrum of the source is well-fitted by the sum of a
blackbody component with a temperature of about 0.4 keV plus a power law
component with photon index about 4. We found no pulsations down to 4% in the
0.01-0.16 Hz range and down to 25% in the 0.01-128 Hz range. This source
resembles other compact central objects (CCOs) in SNRs, and we suggest that
1WGA J1713.4-3949 is the associated neutron star for G347.3--0.5. We also
measured the properties of the adjacent radio pulsar PSR J1713-3945 with a 392
ms period and show that it is not associated with 1WGA J1713.4-3949 nor, most
probably, with SNR G347.3-0.5 as well.Comment: 8 pages, 2 figures, accepted for publication in ApJ Letter
A Submillimeter HCN Laser in IRC+10216
We report the detection of a strong submillimeter wavelength HCN laser line
at a frequency near 805 GHz toward the carbon star IRC+10216. This line, the
J=9-8 rotational transition within the (04(0)0) vibrationally excited state, is
one of a series of HCN laser lines that were first detected in the laboratory
in the early days of laser spectroscopy. Since its lower energy level is 4200 K
above the ground state, the laser emission must arise from the inner part of
IRC+10216's circumstellar envelope. To better characterize this environment, we
observed other, thermally emitting, vibrationally excited HCN lines and find
that they, like the laser line, arise in a region of temperature approximately
1000 K that is located within the dust formation radius; this conclusion is
supported by the linewidth of the laser. The (04(0)0), J=9-8 laser might be
chemically pumped and may be the only known laser (or maser) that is excited
both in the laboratory and in space by a similar mechanism.Comment: 11 pages, 3 figure
Spitzer/IRS Observations of Seyfert 1.8s and 1.9s: A Comparison with Seyfert 1s and Seyfert 2s
We present Spitzer Space Telescope mid-infrared spectra of 12 Seyfert 1.8 and
1.9 galaxies over the 5-38 um region. We compare the spectral characteristics
of this sample to those of 58 Seyfert 1 and Seyfert 2 galaxies from the Spitzer
archives. An analysis of the spectral shapes, the silicate 10 um feature and
the emission line fluxes have enabled us to characterize the mid-IR properties
of Seyfert 1.8/1.9s. We find that the equivalent widths of the 10 um silicate
feature are generally weak in all Seyfert galaxies, as previously reported by
several studies. The few Seyfert galaxies in this sample that show deep 10 um
silicate absorption features are highly inclined and/or merging galaxies. It is
likely that these absorption features originate primarily in the dusty
interstellar medium of the host galaxy rather than in a dusty torus on parsec
scales close to the central engine. We find that the equivalent width of the
polycyclic aromatic hydrocarbon (PAH) band at 6.2 um correlates strongly with
the 20-30 um spectral index. Either of these quantities are good indicators of
the amount of starburst contribution to the mid-IR spectra. The spectra of
Seyfert 1.8 and 1.9s are dominated by these starburst features, similar to most
Seyfert 2s. They show strong PAH bands and a strong red continuum toward 30 um.
The strengths of the high-ionization forbidden narrow emission lines [O IV]
25.89 um, [Ne III] 15.56 um and [Ne V] 14.32 um relative to [Ne II] 12.81 um
are weaker in Seyfert 1.8/1.9s and Seyfert 2s as compared to Seyfert 1s. The
weakness of high-ionization lines in Seyfert 1.8-1.9s is suggestive of
intrinsically weak active galactic nuclei (AGN) continua, and/or stronger star
formation activity leading to enhanced [Ne II]. We discuss the implications of
these observational results in the context of the Unified Model of AGN.Comment: 36 pages, 4 tables, 6 figures, Accepted for publication in The
Astrophysical Journal, December 200
Commissioning of the electron injector for the AWAKE experiment
The advanced wakefield experiment (AWAKE) at CERN is the first proton beam-driven plasma wakefield acceleration experiment. The main goal of AWAKE RUN 1 was to demonstrate seeded self-modulation (SSM) of the proton beam and electron witness beam acceleration in the plasma wakefield. For the AWAKE experiment, a 10-meter-long Rubidium-vapor cell together with a high-power laser for ionization was used to generate the plasma. The plasma wakefield is driven by a 400 GeV/c proton beam extracted from the super proton synchrotron (SPS), which undergoes a seeded self-modulation process in the plasma. The electron witness beam used to probe the wakefields is generated from an S-band RF photo-cathode gun and then accelerated by a booster structure up to energies between 16 and 20 MeV. The first run of the AWAKE experiment revealed that the maximum energy gain after the plasma cell is 2 GeV, and the SSM mechanism of the proton beam was verified. In this paper, we will present the details of the AWAKE electron injector. A comparison of the measured electron beam parameters, such as beam size, energy, and normalized emittance, with the simulation results was performed
- âŚ