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The Development and Application of Capillary Absorption Cells

Description: Abstract: "Various types of capillary absorption cells have been constructed from a variety of materials. These cells, having volumes as low as 160 microliters, have been used to increase the sensitivity of several colorimetrics methods as much as 1000 fold without appreciable loss of accuracy. Small volumes of solution must be used in order to concentrate the colored material present."
Date: 1951
Creator: Rosenfels, R. S.; Kirk, P. L.; Kitson, R. E.; Patton, R. L. & Curtis, R. E.
Partner: UNT Libraries Government Documents Department

Progress in vacuum-ultraviolet spectroscopy

Description: A photoelectron spectrometer is built which analyzes for the kinetic energy of the photoionized electrons by retardation techniques. The signal to noise ratio is very high due to the use of a new lamp and increasing the aperture of the system. The resolution is found to be extremely low and the sources of difficulties are discussed and are being eliminated.
Date: June 1, 1967
Partner: UNT Libraries Government Documents Department

Measured chromium distributions resulting from cooling tower drift

Description: Useful data concerning the distribution of drift from a mechanical draft cooling tower were derived from field measurements despite the non-ideal conditions which were encountered. Observed chromium fluxes ranged from about 1 mg (m/sup 2/hr)/sup -1/ at a distance of 30 m from the tower to about 1% of that value at a kilometer. Air concentrations of chromium were fairly constant at about 50 ng m/sup -3/ to a distance of about 200 m downwind of the tower, apparently due to thorough mixing in the wake of the tower and a lack of lateral dilution of the effiuent from a crosswind line source. A simplified droplet trajectory model appears capable of estimating drift deposition flux within an order of magnitude. Neither that model nor the experimental data are sufficiently detailed to permit definitive assessment of cooling tower drift. The proper assessment of cooling tower drift deposition for general application would require a comprehensive investigation centered on an isolated cooling lower whose operational characteristics are well-defined and subject ulo cont rol. Documentation of the drift droplet spectrum and properties of the buoyant plume and the adjacent atmosphere are essential to such an effont. (auth)
Date: January 1, 1973
Creator: Alkezweeny, A.J.; Glover, D.W.; Lee, R.N.; Sloot, J.W. & Wolf, M.A.
Partner: UNT Libraries Government Documents Department

Research applications of synchrotron radiation. Proceedings of a study- symposium held at Brookhaven National Laboratory, September 25--28, 1972

Description: The conference covers biological diffraction, x-ray diffraction in biology, protein structure determination by diffraction, x-ray microscopy, uv absorption studies on biophysical systems, biological responses to ionizing radiations, holography, far ultraviolet photochemistry, free atoms and molecules, x-ray astronomy. (JFP)
Date: June 1, 1973
Creator: Watson, R.E. & Perlman, M.L. (eds.)
Partner: UNT Libraries Government Documents Department

Collision Broadening in the Microwave Rotational Spectrum of Gaseous Monomeric Formaldehyde

Description: A source-modulation microwave spectrograph was utilized to measure line width parameters for several spectral lines in the pure rotational spectrum of formaldehyde (H₂CO). The spectrograph featured high-gain ac amplification and phase-sensitive detection, and was capable of measuring microwave lines having absorption coefficients as small as 10⁻⁷ cm⁻¹ with a frequency resolution on the order of 30 kHz. Center frequencies of the measured lines varied from 4,830 MHz to 72,838 MHz; hence, most of the observations were made on transitions between K-doublets in the rotational spectrum. Corrections were applied to the measured line width parameters to account for Doppler broadening and, where possible, for deviations due to magnetic hyperfine structure in some of the K-doubled lines. Low modulation voltages and low microwave power levels were used to minimize modulation and saturation broadenings; other extraneous broadenings were found to be insignificant. The primary broadening mechanism at low gas pressure is pressure broadening, and a review of this topic is included. Line width parameters for the several observed transitions were determined by graphing half-widths versus pressure for each spectral line, and performing a linear least-squares fit to the data points. Repeatability measurements indicated the accuracy of the line width parameters to be better than ±10 percent. The reasons for this repeatability spread are discussed, Broadening of each line was measured for self- and foreign-gas broadening by atomic helium and diatomic hydrogen. Effective collision diameters were calculated for each broadening interaction, based on the observed rates of broadening.
Date: December 1973
Creator: Rogers, David Valmore
Partner: UNT Libraries