Čerenkov radiation and electromagnetic pulse produced by electron beams traversing a finite path in air

Coherent Čerenkov radiation has been investigated previously in the time domain for an infinite path. The present calculations for a finite path length show an effect analogous to diffraction (in the frequency domain) in which radiation fields appear both at Cerenkov angles and at other angles. The latter have previously been named electromagnetic pulse fields.Hydrodynamics Group, Los Alamos National Laboratory, For Fred R. Buskirk and the U.S. Naval Sea Systems Command.Approved for public release; distribution is unlimited

Balanced Orifice Plate

An orifice plate for use in a conduit through which fluid flows is defined by a central circular region having a radius R, and a ring-shaped region surrounding the central circular region. The ring-shaped region has holes formed therethrough with those holes centered at each radius R thereof satisfying a relationship A(sub R)=al(X(sub R)V(sub R)(sup b)) where A(sub R) is a sum of areas of those holes having centers at radius R, X(sub R) is a flow coefficient at radius R, V(sub R) is a velocity of the fluid that is to flow through the conduit at radius R, b is a constant selected to make at least one process variable (associated with the fluid that is to flow through the conduit) approximately equal at each radius R, and a is a constant that is equal to (X(sub R)A(sub R)V(sub R)(sup b)) at each radius R

Gas volume contents within a container, smart volume instrument

A method for determining the volume of an incompressible gas in a system including incompressible substances in a zero-gravity environment. The method includes inducing a volumetric displacement within a container and measuring the resulting pressure change. From this data, the liquid level can be determined

PRICING AND USE OF DROUGHT-STRESSED AND IMMATURE CORN AS SILAGE FOR BEEF CATTLE

Demand and Price Analysis,

Analysis, Design and Fabrication of centimeter-wave Dielectric Fresnel Zone Plate Lens and reflector

Fresnel lens has a long history in optics. This concept at non-optical wavelengths is also applicable. In this paper we report design and fabrication of a half and quarter wave dielectric Fresnel lens made of Plexiglas, and a Fresnel reflector at 11.1 GHz frequency. We made two lenses and one reflector at same frequency and compare their gain and radiation pattern to simulated results. Some methods for better focusing action will be introduced

Giant multipole resonances in the deformed fissionable nucleus 238U: breakdown of the hydrodynamical models?

The deformed, fissionable nucleus 238u was studied with inelastic scattering of 87.5 MeV electrons between 5 and 40 MeV excitation energy with inelastic momentum transfers ranging from 0.32 fm -1 to 0.58 fm -1 for an excitation energy of 15 MeV. Resonance cross sections extracted were compared with DWBA calculations using the Goldhaber-Teller, Steinwedel-Jensen, and Myers-Swiatecki models of the giant resonance. It is demonstrated that up to the first minimum of the form-factor the cross section is nearly completely determined by one parameter, the transition radius Rtr. Using the known systematics of various multipole resonances in other, non-fissionable, nuclei as a guide, it was found that the assumed ground state radius of 238u had to be enlarged by about 10% for all multipolarities, to bring the strength found in agreement with the systematics and with other experiments in 238u. In particular, while the model-independent values for position and width of the GDR agree well with photon experiments, a scaled version of the Myers-Swiatecki model had to be used to produce agreement in strength. Similarly a scaled Goldhaber-Teller model was used for the isoscalar E2 resonance at 9.9 MeV. The situation for the isovector states above the GDR, E2 and E3 (or EO) is even more complicated. It is argued that with proper caution and consideration of other available data the use of the collective models mentioned above may give valuable insight into the charge distribution of 238u at higher excitation energies

Resonant octupole strength at 13 MeVin (58)Ni and (60)Ni and the character of the 53A(-1/3) state in heavy nuclei

Inelastic electron scattering reveals a concentration of resonant E3 strength at (13.3 ± 0.2) MeV in 51Ni and (12.8 ± 0.2) MeV in 60Ni. The energy agrees closely with the 52 A- 1/ ' MeV predicted by Hamamoto for the isovector (1 hwl E3 mode on the basis of the Bohr-Mottelson self-consistent shell model, but the strength, (13 ± 1)% and (8 ± 2)% of the energy weighted sum rule, respectively, is a factor of 5 too large. This result weakens recent arguments in favor of a monopole assignment for the 53 A-i/ 3 MeV resonance found by (e,e'l in heavy nuclei.National Science FoundationNaval Postgraduate School Foundatio

Unbalanced-flow, fluid-mixing plug with metering capabilities

A fluid mixer plug has holes formed therethrough such that a remaining portion is closed to fluid flow. The plug's inlet face defines a central circuit region and a ring-shaped region with the ring-shaped region including at least some of the plug's remaining portion so-closed to fluid flow. This remaining portion or closed region at each radius R of the ring shaped region satisfies a radius independent, flow-based relationship. Entry openings are defined in the plug's inlet face in correspondence with the holes. The entry openings define an open flow area at each radius of the ring-shaped region. The open flow area at each such radius satisfies the inverse of the flow-based relationship defining the closed regions of the plug

Fish Colonization of a Newly Deployed Vessel-reef off Southeast Florida: Preliminary Results

Fish colonization on the Ebenezer II, a 25.5m merchant marine vessel, was studied from May 2002 - July 2003. The ship was scuttled in May 2002 off Broward County, Florida at a depth of 21m and was censused 10 times during the study period using a modified Bohnsack and Bannerot visual census method. Adjacent natural reefs and the Mcallister, a nearby, 30m tugboat deployed in June 1998, were censused during the same period. Distinct changes in the fish assemblage on the Ebenezer II were observed throughout the sample period. A pioneer assemblage was observed during the first three months, characterized by the settlement of juvenile fishes «5 cm). Subsequently, numbers of juveniles decreased either through emigration, predation or growth. Resident species made up 52.5% of the total abundance but transient fish species made up 78% of the total fish biomass during the study period. Surprisingly, attraction of adult fish from both natural reefs and the Mcallister was not a major factor in assemblage fonnation. The primary adult fishes attracted to the Ebenezer II were herbivores. These fishes steadily increased in abundance throughout the study period, presumably due to increased food availability as benthic algal communities developed. A similar trend of increasing herbivores with increasing soak time was observed on the Spiegel Grove, a 153m vessel-reef sunk off Key Largo in May 2002. The fish assemblages on the artificial reefs were more similar to each other than to natural reefs. Vessel-reefs had sixty species in common, while the Ebenezer II only had thirty-nine species in common with natural reefs. Several species common to vessel-reefs were absent or rare on nearby natural reefs. This may indicate that vessel-reefs are providing early juvenile and adult habitat that is not available on natural reefs