Monte Carlo Calculations of Neutron Number Spectra and Buildup Factors in Infinite Conical Configurations

A Monte Carlo code simulating neutron transport in infinite cones of water and water-equivalent hydrogen was prepared for an IBM 704 computer. The code was essentially a modification of the point-source, infinite-medium code used in NASA TN D-850. Studies were made of differential neutron number spectra and associated buildup factors for infinite cones having apex half-angles of 15 degrees, 30 degrees, 45 degrees, and 60 degrees. The buildup factors obtained were compared with those for the appropriate infinite medium, which allowed an examination of the effect of solid angle subtended by material on the transport of 6-Mev source neutrons emanating from the cone apex. The variation of number buildup factor with distance for the various cones shows that neutron scattering out of the cones is predominant in the first 30 t o 40 centimeters of material, and that transport beyond this distance is of a similar nature in all the cones

Improved consolidation of silicon carbide

Alpha silicon carbide powder was consolidated by both dry and wet methods. Dry pressing in a double acting steel die yielded sintered test bars with an average flexural strength of 235.6 MPa with a critical flaw size of approximately 100 micro m. An aqueous slurry pressing technique produced sintered test bars with an average flexural strength of 440.8 MPa with a critical flaw size of approximately 25 micro m. Image analysis revealed a reduction in both pore area and pore size distribution in the slurry pressed sintered test bars. The improvements in the slurry pressed material properties are discussed in terms of reduced agglomeration and improved particle packing during consolidation

A new Lyropecten (Pectinidae, Bivalvia, Mollusca) from the central California Miocene, USA

A new pectinid, Lyropecten terrysmithae n. sp., has been recognized in middle to late Miocene rock units referred to as the Monterey Formation and Santa Margarita Sandstone in the southern Salinas Valley, central California. Previously, L. terrysmithae had been identified as a flat form belonging to either L. estrellanus or L. catalinae, then more recently to Argopecten sp. The earlier assignments were based on its moderate size and a radial rib count nearly identical to these taxa. However, its hinge, flat unledged valves, looped lamellar growth lines, and hinge crura set L. terrysmithae apart from Argopecten and all species of Lyropecten. Localities where it occurs in the Salinas Valley that can be accurately dated are from the late middle to middle late Miocene “Margaritan” California provincial molluscan stage. While L. terrysmithae has been collected at other sites, those localities lack diagnostic age-specific species necessary to determine an accurate geological age and maybe older

Induction Furnace Smelting of Montana Chromite

In 1939 the total world production of crude chromite was approximately 1,167,000 metric tons; of which the United States produced only 3,672 metric tons and imported over 317,500 metric tons. Imports came mostly from the Philippine Islands, Cuba, South Africa, and Rhodesia

Section 254 of the Telecommunications Act of 1996: A Hidden Tax?

Congress has the sole power to levy and collect taxes. The Supreme Court has ruled that Congress may delegate this authority to administrative agencies so long as the will of Congress is clearly defined in the legislation. However, section 254 of the Telecommunications Act of 1996 operates as an unconstitutional delegation of Congress\u27 authority to tax. This legislation provides the FCC with unfettered discretion in defining the boundaries of universal service and the authority to mandate that all consumers of telecommunications services subsidize the cost for low-income and rural consumers, as well as schools, libraries, and health care providers

Ideal and Practice in a State Constitution: The Case of Minnesota

Minnesota badly needs a revised constitution that generally and broadly defines and distributes powers, responsibilities and rights, and sets up a general frame of government. While this might be accomplished through the amendment process, it has been painfully slow and up to now inadequate to meet \u27the needs for modern, flexible and responsive state government. A constitutional convention may still be the best and most practical way of achieving needed revisions

Development and test of video systems for airborne surveillance of oil spills

Five video systems - potentially useful for airborne surveillance of oil spills - were developed, flight tested, and evaluated. The systems are: (1) conventional black and white TV, (2) conventional TV with false color, (3) differential TV, (4) prototype Lunar Surface TV, and (5) field sequential TV. Wavelength and polarization filtering were utilized in all systems. Greatly enhanced detection of oil spills, relative to that possible with the unaided eye, was achieved. The most practical video system is a conventional TV camera with silicon-diode-array image tube, filtered with a Corning 7-54 filter and a polarizer oriented with its principal axis in the horizontal direction. Best contrast between oil and water was achieved when winds and sea states were low. The minimum detectable oil film thickness was about 0.1 micrometer

Infrared-temperature variability in a large agricultural field

The combined effect of water carved gullies, varying soil color, moisture state of the soil and crop, nonuniform phenology, and bare spots was measured for commercially grown barley planted on varying terrain. For all but the most rugged terrain, over 80% of the area within 4, 16, 65, and 259 ha cells was at temperatures within 3 C of the mean cell temperature. The result of using relatively small, 4 ha instantaneous field of views for remote sensing applications is that either the worst or the best of conditions is often observed. There appears to be no great advantage in utilizing a small instantaneous field of view instead of a large one for remote sensing of crop canopy temperatures. The two alternatives for design purposes are then either a very high spatial resolution, of the order of a meter or so, where the field is very accurately temperature mapped, or a low resolution, where the actual size seems to make little difference

Planning applications in east central Florida

There are no author-identified significant results in this report

LANDSAT planning applications in east central Florida

There are no author-identified significant results in this report