Measurement of the Intensity of Turbulence

Spectral broadening of scattered light using Doppler heterodyne technique, and velocity profiles for laminar flow in a duc

Separate reference beam holographic interferometry and its application to the measurement of small phase variations in sub-fringe systems

Application of separate reference beam holographic interferometry for measurement of small phase variations in sub-fringe system

Directional acoustic measurements by laser Doppler velocimeters

Laser Doppler velocimeters (LDVs) were used as velocity microphones to measure sound pressure level in the range of 90-130 db, spectral components, and two-point cross correlation functions for acoustic noise source identification. Close agreement between LDV and microphone data is observed. It was concluded that directional sensitivity and the ability to measure remotely make LDVs useful tools for acoustic measurement where placement of any physical probe is difficult or undesirable, as in the diagnosis of jet aircraft noise

Digital Systems for On-Site Collection for Water Quality Analysis

A prototype system has been developed for recording and transmitting digital data at a remote water quality monitoring station in an unattended manner. As many as eight analog signals from transducers, which measure water quality characteristics such as dissolved oxygen, temperature, pH, chlorides, conductivity, redox, and turbidity, are converted to digital signals and recorded in binary coded decimal format on magnetic tape. This unit may be contacted from a central station for playback of the day\u27s recording. The transmitted data can be recorded at the central station by teletype. Each data record includes a time-of-day word so that all data is identifiable. The techniques developed during this contract period have possible application in many areas of water resource research, particularly for use in making water quality measurements in remote areas or at numerous sites reporting to one central station

Basic experimental research leading to improved cold electron sources and new types of velocity filter mass spectrometers Final report

Long duty cycle mass spectrometer for space research and source of cold electrons for ionizing neutral gas molecules in mass spectromete

Study of the effects of condensation on the performance of Pioneer Venus probe windows

The transmission loss of Pioneer Venus Probe radiation windows if their exposed surfaces become contaminated with droplets of water, hydrochloric acid, sulfuric acid, and mercury which may be found in the Venusian atmosphere was investigated. Transmission loss was studied as a function of mass concentration of liquid droplets deposited on one surface of test window materials while the wavelength of the transmitting radiation is in the range of 0.3 to 30 microns. The parameters that affect the transmittance of radiation through a window are: (1) particle size, (2) surface concentration of particles, (3) wavelength of the radiation, (4) angle of acceptance of the radiation by the detector, and (5) the refractive index of the aerosol

Investigation of laser properties relevant to the measurement of different physical parameters Semiannual status report, 1 Mar. - 1 Sep. 1965

Laser properties relevant to measurement of physical parameters - mapping vibrating surface, frequency response of transducer, sensitive level, pressure determination, and hologram

Investigation of laser properties relevant to the measurement of different physical parameters Informal status progress report

Laser properties relevant to measuring physical parameter

A Study to Improve Dissolved Oxygen Analysis Techniques to Facilitate Water Quality Field Survey Applications

This report describes studies made of the temperature characteristics of dissolved oxygen electrodes having a large surface area. Large area electrodes proved to have much longer lifetime between rejuvenations. Many measurements of dissolved oxygen in water need to be made in field situations where recalibration techniques would be difficult and where making temperature corrections is time consuming for operators who may be making numerous measurements. This study was directed toward design of a compensation circuit for a dissolved oxygen electrode which will give the best possible measurement over a large water temperature range of 5° - 35°C without the necessity of recalibration. Studies were made of the temperature characteristics of dissolved oxygen probes and several electronic circuits with different configurations and components are described. Experimental data using two of the circuits are reported. One method involved using an integrated circuit multiplier module. The best temperature compensation was obtained for a circuit based on a design in which two thermistors were incorporated

The effect of high temperature upon the transmittance and the emission spectrum of infrared window materials

The effect of high temperatures such as those expected to be encountered in the Pioneer Venus Probe mission upon the transmittance of zinc selenide and cadmium telluride infrared window materials was investigated and the radiation emitted by these materials at high temperatures was determined