2,695 research outputs found
Ultrasonic Doppler measurement of renal artery blood flow
Studies were made of (1) blood flow redistribution during lower body negative pressure (LBNP), (2) the profile of blood flow across the mitral annulus of the heart (both perpendicular and parallel to the commissures), (3) testing and evaluation of a number of pulsed Doppler systems, (4) acute calibration of perivascular Doppler transducers, (5) redesign of the mitral flow transducers to improve reliability and ease of construction, and (6) a frequency offset generator designed for use in distinguishing forward and reverse components of blood flow by producing frequencies above and below the offset frequency. Finally methodology was developed and initial results were obtained from a computer analysis of time-varying Doppler spectra
The effects of seismic blasting on shallow water wells and aquifers in western North Dakota
Seismographic petroleum exploration throughout North Dakota has generated concern over the effects of blasting on groundwater supplies and wells. A preliminary investigation revealed complaints alleging declining productivity and decreased water quality in regions where coal aquifers are extensively used. Unplugged shotholes were frequently cited as a source of problems.
Experimental results indicate that changes due to blasting occur within long term physical the aquifers rather than in specific water wells. Pumping tests conducted in a sand and coal aquifer system showed no apparent physical effects when shots were detonated one quarter mile away from the pumping wells. Shots 500 feet distant resulted in no permanent effects. Shots 100 feet or closer increased the yield from wells finished in the sand aquifer and decreased the yield from the coal aquifer. Fracturing of the poorly indurated sandstone aquifer is suggested as a mechanism for the increase. Collapse of fractures is suggested as the failure mechanism in the coal aquifer. Well casings remained intact after 25 pound charges were detonated as close as 10 feet from a well screen. Currently available methods for evaluating pump test data do not adequately were also provided. Rick Nelson, Environmental Engineer, served as the Health Department liasion. Rod Reetz and Ken Kary of the North Dakota State Department of Health Laboratories were especially helpful in expediting the sample analyses in the face of staggering backlogs of samples from other sources.
The North American Coal Corporation deserves special consideration for their willingness to let us use their land holdings as an experimental site. Site consolidation made the logistics much more manageable than they would have been with multiple sites. Jim Brown, Director of Environmental· Control, was instrumental in obtaining permission within the company and Terry Zich, Hydrologist, served as a cooperative and helpful liaison;
Keith Whittemore of the Amoco Oil Company, and P. D. O\u27Brien of Grant Geophysical Inc., and J. R. Freeman travelled to Grand Forks in midwinter to discuss the project and to offer assistance. Jim Reil of Vibra-Tech Engineers donated the use of a portable seismograph and analyzed the data collected.
My wife and daughters have been especially tolerant of my absences during the fieldwork and preparation of this thesis. Without their cooperation, this endeavor would not have been possible. address coal fracture permeability. Consequently, values for transmissivity, storativity, and specific yield were unobtainable.
During the pumping tests, no significant long term chemical or mineralogical equilibrium changes were observed which could be attributed to the blasting. Water quality changes resulted from pumping during the early time segments of the pump tests. Immediately following a shot 100 feet from a pumping well finished in coal, a short term increase in most chemical parameters was noted. Shots farther away had no apparent effect on chemical quality. Well owners and explorers are advised to collect water quality and pumping drawdown data before any exploration is conducted. The relative productivity of any well can be determined by pumping the well and noting the drawdown with time. If done prior to exploration, these measures provide an excellent basis for evaluation of the effects of blasting
Development of fishery regulations using confounded data: a case study from the south Florida Greater Amberjack fishery
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Impact of Temperature, Ethanol and Cell Wall Material Composition on Cell Wall-Anthocyanin Interactions.
The effects of temperature and ethanol concentration on the kinetics of anthocyanin adsorption and desorption interactions with five cell wall materials (CWM) of different composition were investigated. Using temperatures of 15 °C and 30 °C and model wine with ethanol concentrations of 0% and 15% (v/v) over 120 min, the adsorption and desorption rates of five anthocyanin-glucosides were recorded in triplicate. Small-scale experiments were conducted using a benchtop incubator to mimic a single berry fermentation. Results indicate that more than 90% of the adsorption occurs within the first 60 min of the addition of anthocyanins to CWM. However, desorption appears to occur much faster, with maximum desorption being reached after 30 min. The extent of both adsorption and desorption was clearly dependent not only on temperature and ethanol concentration but also on the CWM composition
Fatigue Strength and Related Characteristics of Joints in 24s-t Alclad Sheet
Report includes tension fatigue test results on the following types of samples of 0.040-inch alclad 24s-t: (1) monoblock sheet samples as received and after a post-aging heat treatment, (2) "sheet efficiency" samples (two equally stressed sheets joined by a single transverse row of spot welds) both as received and after post-aging, (3) spot-welded lap-joint samples as received and after post-aging, and (4) roll-welded lap-joint samples. (author
Fatigue Strength and Related Characteristics of Aircraft Joints II : Fatigue Characteristics of Sheet and Riveted Joints of 0.040-inch 24S-T, 75S-T, and R303-T275 Aluminum Alloys
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