1,849 research outputs found
Studies at Oyster Bay in Jamaica, West Indies. I. Intensity patterns of bioluminescence in a natural environment
Night and day patterns in the intensities of stimulable bioluminescense in Pyrodinium bahamense were measured during the period of April 1966 through May 1967 in Oyster Bay, Falmouth Harbor, Jamaica, West Indies…
The Three Component Electronic Structure of the Cuprates Derived from SI-STM
We present a phenomenological model that describes the low energy electronic
structure of the cuprate high temperature superconductor Bi2Sr2CaCu2O8+x as
observed by Spectroscopic Imagining Scanning Tunneling Microscopy (SI-STM). Our
model is based on observations from Quasiparticle Interference (QPI)
measurements and Local Density of States (LDOS) measurements that span a range
of hole densities from critical doping, p~0.19, to extremely underdoped,
p~0.06. The model presented below unifies the spectral density of states
observed in QPI studies with that of the LDOS. In unifying these two separate
measurements, we find that the previously reported phenomena, the Bogoliubov
QPI termination, the checkerboard conductance modulations, and the pseudogap
are associated with unique energy scales that have features present in both the
q-space and LDOS(E) data sets
Biological and physical observations on a phosphorescent bay in Falmouth Harbor, Jamaica, W. I.
A general description of a phosphorescent bay on the northern shore of Jamaica, West Indies, is presented. The brilliant bioluminescence in this embayment is due to the large armored dinoflagellate, Pyrodinium bahamense. It was found in cell densities as high as 200,000 cells/liter. Using a submersible spectrometer, the bioluminescent emission spectrum of these organisms was found to peak at 476 mµ...
Ultraviolet absorption: Experiment MA-059
A technique devised to permit the measurement of atmospheric species concentrations is described. This technique involves the application of atomic absorption spectroscopy and the quantitative observation of resonance fluorescence in which atomic or molecular species scatter resonance radiation from a light source into a detector. A beam of atomic oxygen and atomic nitrogen resonance radiation, strong unabsorbable oxygen and nitrogen radiation, and visual radiation was sent from Apollo to Soyuz. The density of atomic oxygen and atomic nitrogen between the two spacecraft was measured by observing the amount of resonance radiation absorbed when the line joining Apollo and Soyuz was perpendicular to their velocity with respect to the ambient atmosphere. Results of postflight analysis of the resonance fluorescence data are discussed
Space Station Engineering Design Issues
Space Station Freedom topics addressed include: general design issues; issues related to utilization and operations; issues related to systems requirements and design; and management issues relevant to design
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Laboratory test results on the thermal resistance of polyisocyanurate foamboard insulation blown with CFC-11 substitutes: A cooperative industry/government project
The fully halogenated chlorofluorocarbon gases (CFC-11 and CFC-12) are used as blowing agents for foam insulations for building and appliance applications. The thermal resistance per unit thickness of these insulations is greater than that of other commercially available insulations. Mandated reductions in the production of these chemicals may lead to less efficient substitutes and increase US energy consumption by one quad or more. This report describes laboratory thermal and aging tests on a set of industry-produced, experimental polyisocyanurate (PIR) laminate boardstock to evaluate the viability of hydrochlorofluorocarbons (HCFSs) as alternative blowing agents to chlorofluorcarbon-11 (CFC-11). The PIR boards were blown with five gases: CFC-11, HCFC- 123, HCFC-141b, and 50/50 and 65/35 blends of HCFC-123/HCFC-141b. These HCFC gases have a lower ozone depletion potential than CFC-11 or CFC-12. Apparent thermal conductivity (k) was determined from 0 to 50{degrees}C. Results on the laminate boards provide an independent laboratory check on the increase in k observed for field exposure in the Roof Thermal Research Apparatus (RTRA). The measured laboratory increase in k was between 8 and 11% after a 240-d field exposure in the RTRA. Results are reported on a thin-specimen, aging procedure to establish the long-term thermal resistance of gas-filled foams. These thin specimens were planed from the industry-produced boardstock foams and aged at 75 and 150{degrees}F for up to 300 d. The resulting k-values were correlated with an exponential dependency on (diffusion coefficient {times} time){sup {1/2}}/thickness and provided diffusion coefficients for air components into, and blowing agent out of, the foam. This aging procedure was used to predict the five-year thermal resistivity of the foams. The thin-specimen aging procedure is supported with calculations by a computer model for aging of foams. 43 refs., 33 figs., 25 tabs
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