Engineering topics
Publications and source records attributed to Peterson, J. B..
In this paper we present a similar analysis of the Tucker at al. (1993, hereafter T93) White Dish CMB anisotropy data collected at the South Pole. The white dish detector and telescope are described in Tucker et al. (1994).
Observations of a low-background region of sky at high Galactic latitude in a frequency band centered at nu = 90 GHz reveal highly significant detections of anisotropy on intermediate (aprroximately 1 deg) angular scales. The instrument is a 2 x 2 array of bolometric detectors operating at 50 mK, coupled to a 0.75 m off-axis parabolic telescope by single-mode corrugated feedhorns. The FWHM beamwidth of the instrument is 0.75 deg, with a beamswitch of +/- 2.75 deg on the sky. Interpreting the detected fluctuations as due to anisotropy in the cosmic microwave background, a likelihood analysis assuming a Gaussian correlation function in the temperature fluctuations yields most likely values of (delta T)/T of 3.1(sub -0.9)(sup +2.5) x 10(exp -5) and 3.8(sub -1.2)(sup +2.9) x 10(exp -5) at a coherence angle of 1.0 deg, for the left- and right-hand detectors, respectively. The stated errors are 95% confidence limits. Confirmation at other frequencies is required to rule out the possibility of foreground contamination.
The U.S. Bureau of Mines has developed a technique for dewatering mineral waste slurries which utilizes polymer and a static screen. A variety of waste slurries from placer gold mines and crushed stone operations have been successfully treated using the system. Depending on the waste, a number of polymers have been used successfully with polymer costs ranging from $0.05 to $0.15 per 1,000 gal treated. The dewatering is accomplished using screens made from either ordinary window screen or wedge wire. The screens used are 8 ft wide and 8 ft long. The capacity of the screens varies from 3 to 7 gpm/sq. ft. The water produced is acceptable for recycling to the plant or for discharge to the environment. For example, a fine grain dolomite waste slurry produced from a crushed stone operation was dewatered from a nominal 2.5 pct solids to greater than 50 pct solids using $0.10 to $0.15 worth of polymer per 1,000 gal of slurry. The resulting waste water had a turbidity of less than 50 NTU and could be discharged or recycled. The paper describes field tests conducted using the polymer-screen dewatering system.
The brightness temperature of the sky is measured in five bands from 1 to 3 mm using apparatus related to that of Woody and Richards (1981) and Peterson et al. (1985). Examination of the data reveals the presence of two previously unknown systematic effects which limit the accuracy of the measurements. Similar systematic effects are most likely present in the data obtained previously with this apparatus. Upper limits to the temperature of the cosmic background radiation are set in four bands; the most stringent is T(CBR) less than 2.88 K at 1.1 mm (95 percent CL).
The anisotropy of the diffuse background radiation has been measured with a 10-deg FWHM beam in a broad spectral band from 0.6 to 4.0 mm. A dipole anisotropy is detected with magnitude consistent with previous measurements; the present data may, however, be contaminated by atmospheric emission. Upper limits are set to fluctuations at higher-order multipoles. The most stringent limit is at l = 4, where a 95-percent confidence-level limit of less than 0.00025 is set. The observed level of isotropy sharply constrains the possibility of local astronomical origin for the submillimeter excess.
The spectrum of the cosmic background radiation in five frequency bands extending from 2.3 to 11.0 cm with a balloon-borne liquid-helium-cooled photometer. The photometer compares the flux from the sky to the flux from an internal blackbody at 3.2 K. All five measurements are consistent with temperatures in the range 2.78 + or = 0.11 K, which is in good agreement with tempratures measured at lower frequencies. No significant deviation from a thermal spectrum was found.
The present cryogenic blackbody reference, or 'cold load', for mm-wavelength radiation has an emissivity of more than 0.99 over a two-octave wavelength range and can be used as a calibrating standard for sensitive IR photometers. The transmittance spectrum obtained indicates that wave impedance and index do not vary significantly over the 80-360 GHz range.
Airfoil has least amount of drag under given restrictions of boundary layer transition position, lift coefficient, thickness ratio, and Reynolds number based on airfoil chord. It is suitable for use as wing and propeller aircraft sections operating at subsonic speeds and for hydrofoil sections and blades for fans, compressors, turbines, and windmills.
The continuity of a narrow meandering strip of Udoll (prairie) soils running east and west for approximately 40 miles across north central Indiana in an area predominantly of Udalfs (timber soils) was detected from LANDSAT-1 data taken on June 9, 1973. This data was processed through a clustering procedure and classified with resulting increased definition of the boundaries among soils grouped according to nine categories and vegetation to two categories of reflectance. This dark stretch of prairie soil is believed to have formed in the heavy textured, poorly drained glacial debris which filled a major pre-glacial tributary of the Teays River System. Ready identification and location of the valley has significance to soil survey and land classification people as a guide to soil classification and land use and to geologists as a guide to location of a potentially economically significant aquifer.