6,126 research outputs found
Combining Harmonic Generation and Laser Chirping to Achieve High Spectral Density in Compton Sources
Recently various laser-chirping schemes have been investigated with the goal
of reducing or eliminating ponderomotive line broadening in Compton or Thomson
scattering occurring at high laser intensities. As a next level of detail in
the spectrum calculations, we have calculated the line smoothing and broadening
expected due to incident beam energy spread within a one-dimensional plane wave
model for the incident laser pulse, both for compensated (chirped) and
unchirped cases. The scattered compensated distributions are treatable
analytically within three models for the envelope of the incident laser pulses:
Gaussian, Lorentzian, or hyperbolic secant. We use the new results to
demonstrate that the laser chirping in Compton sources at high laser
intensities: (i) enables the use of higher order harmonics, thereby reducing
the required electron beam energies; and (ii) increases the photon yield in a
small frequency band beyond that possible with the fundamental without
chirping. This combination of chirping and higher harmonics can lead to
substantial savings in the design, construction and operational costs of the
new Compton sources. This is of particular importance to the the widely popular
laser-plasma accelerator based Compton sources, as the improvement in their
beam quality enters the regime where chirping is most effective.Comment: 5 pages, 4 figure
The Hymenopterous Parasites Agathis Pumila (Braconidae) and Epilampsis Laricinellae (Eulophidae) on the Larch Casebearer (Lepidoptera: Coleophoridae) in the Northern Lake States
Excerpt: The larch casebearer Coleophora laricella (Hübner) is a defoliator of larch (Larix spp.). The insect was introduced into North America from Europe at some time prior to 1886, and since has spread steadily westward. It was causing heavy defoliation by the early 1920\u27s near Ann Arbor in southern Michigan and was recorded in northeast Wisconsin in 1939, at Sault Ste. Marie, Ontario in 1942, and Port Arthur, Ontario in 1947.
Many native parasites attack the case bearer but seem to effect little control. Parasites were imported from Europe beginning in 1928, but the first attempts to establish them were unsuccessful. In 1932, the United States Bureau of Entomology and Plant Quarantine made releases of Agathis pumila (Ratz.) at Lynwood, Massachusetts, and Epilampsis laricinellae (Ratz.) in Lunenburg Township, Massachusetts. These two species were successfully established
Susceptibility of a spinon Fermi surface coupled to a U(1) gauge field
We study the theory of a U(1) gauge field coupled to a spinon Fermi surface.
Recently this model has been proposed as a possible description of the organic
compound . We calculate the susceptibility of
this system and in particular examine the effect of pairing of the underlying
spin liquid. We show that this proposed theory is consistent with the observed
susceptibility measurements.Comment: 5 pages, 4 figure
A Study of the Demographic and Socioeconomic Factors Influencing the Placement of Retail and Urgent Care Clinics
Urgent care and retail care clinics are a developing model of health care providers that focuses on immediate walk-in care. This paper explores the influence that hospitals, demographic, and socioeconomic factors have on the placement of these clinics. This study employs a comparative quantitative design to explore the association of these variables with the placement of urgent care and retail clinics in Mississippi’s Public Health Districts I and II, which comprise the northernmost twenty counties in the state. The findings show that a high population size, high median household income, low percent of families in poverty, and a low uninsured rate in the counties were strong indicators of whether a retail or urgent care clinic would be present in a county. The findings also showed that there was a weak association between the presence of hospitals and the presence of urgent care and retail care clinics. This study demonstrates that urgent care and retail clinics are generally not serving the most rural and poor counties
Design of a foldable sunshade as an attachment to a sports bag
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, June 2011."June 2011." Cataloged from PDF version of thesis.The purpose of this project was to design a foldable, lightweight, inexpensive addition to an existing duffel bag that will provide enough shade to cover the user's head and upper torso. The intended user for this product is an athlete who plays the sport of Ultimate Frisbee, as this typically involves bye rounds which some use for napping on the sidelines. The existing products to fill this need are too expensive, heavy, bulky or uncomfortable. The process for designing this feature included an extensive ideation phase, potential user interviews, prototype mock-ups, and the production of a final working prototype. This final prototype is made with the roll-out mat that comes attached to the Under Armour Medium Team Duffel bag and the metal support hoops from a collapsible laundry hamper. This prototype meets all of the product specifications that were based on the requirements of the interviewed users.by Cody A. Rebholz.S.B
Performance statistics of the FORTRAN 4 /H/ library for the IBM system/360
Test procedures and results for accuracy and timing tests of the basic IBM 360/50 FORTRAN 4 /H/ subroutine library are reported. The testing was undertaken to verify performance capability and as a prelude to providing some replacement routines of improved performance
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