142,507 research outputs found
Method and apparatus for eliminating luminol interference material
A method and apparatus for removing porphyrins from a fluid sample which are unrelated to the number of bacteria present in the sample and prior to combining the sample with luminol reagent to produce a light reaction is disclosed. The method involves a pre-incubation of the sample with a dilute concentration of hydrogen peroxide which inactivates the interfering soluble porphyrins. Further, by delaying taking a light measurement for a predetermined time period after combining the hydrogen peroxide-treated water sample with a luminol reagent, the luminescence produced by the reaction of the luminol reagent with ions present in the solution, being short lived, will have died out so that only porphyrins within the bacteria which have been released by rupturing the cells with the sodium hydroxide in the luminol reagent, will be measured. The measurement thus obtained can then be related to the concentration of live and dead bacteria in the fluid sample
The utilization of solar energy to help meet our nation's energy needs
The nation's energy needs, domestic energy resources, and possible future energy resources are briefly discussed in this paper. Three potential solutions, coal, nuclear and solar are compared as to benefits and problems. The paper primarily discusses the options available in using solar energy as a natural energy resource. These options are discussed under the generation of electricity, heating and cooling of buildings, and the production of clean fuel
DOE/NASA Lewis large wind turbine program
An overview of the large wind turbine activities managed by NASA is given. These activities include resuls from the first and second generation field machines (Mod-0A, -1, and -2), the status of the Department of Interior WTS-4 machine for which NASA is responsible for technical management, and the design phase of the third generation wind turbines (Mod-5)
An experimental 100 kilowatt wind turbine generator
Experimental generator consists of two blades mounted on 100 foot tower, driving transmission train and electric generator mounted on top of tower. Machine generates 100 kW of electricity at wind speeds from 18 to 60 miles per hour. Yaw control mechanism automatically orients machine into wind
Large wind turbine generators
The development associated with large wind turbine systems is briefly described. The scope of this activity includes the development of several large wind turbines ranging in size from 100 kW to several megawatt levels. A description of the wind turbine systems, their programmatic status and a summary of their potential costs is included
Phase Structure of Non-Compact QED3 and the Abelian Higgs Model
We review the phase structure of a three-dimensional, non-compact Abelian
gauge theory (QED3) as a function of the number of 4-component massless
fermions. There is a critical up to which there is dynamical fermion
mass generation and an associated global symmetry breaking. We discuss various
approaches to the determination of , which lead to estimates ranging from
to . This theory with N=2 has been employed as an effective
continuum theory for the 2D quantum antiferromagnet where the observed Neel
ordering corresponds to dynamical fermion mass generation. Thus the value of
is of some physical interest. We also consider the phase structure of the
model with a finite gauge boson mass (the Abelian Higgs model).Comment: 14 pages, corrected the normalization of the fermion condensate in
section V, corrected a typo in the reference
Constraints on galaxy formation from alpha-enhancement in luminous elliptical galaxies
We explore the formation of alpha-enhanced and metal-rich stellar populations
in the nuclei of luminous ellipticals under the assumption of two extreme
galaxy formation scenarios based on hierarchical clustering, namely a fast
clumpy collapse and the merger of two spirals. We investigate the parameter
space of star formation time-scale, IMF slope, and stellar yields. In
particular, the latter add a huge uncertainty in constraining time-scales and
IMF slopes. We find that -- for Thielemann, Nomoto & Hashimoto nucleosynthesis
-- in a fast clumpy collapse scenario an [alpha/Fe] overabundance of approx.
0.2 dex in the high metallicity stars can be achieved with a Salpeter IMF and
star formation time-scales of the order 10^9 yr. The scenario of two merging
spirals which are similar to our Galaxy, instead, fails to reproduce
alpha-enhanced abundance ratios in the metal-rich stars, unless the IMF is
flattened during the burst ignited by the merger. This result is independent of
the burst time-scale. We suggest that abundance gradients give hints to
distinguish between the two extreme formation scenarios considered in this
paper.Comment: Accepted for publication in MNRAS, LaTex 2.09 with mn.sty, 13 pages,
5 figure
Laboratory evaluation of a pilot cell battery protection system for photovoltaic applications
An energy storage method for the 3.5 kW battery power system was investigated. The Pilot Cell Battery Protection System was tested for use in photovoltaic power systems and results show that this is a viable method of storage battery control. The method of limiting battery depth of discharge has the following advantages: (1) temperature sensitivity; (2) rate sensitivity; and (3) state of charge indication. The pilot cell concept is of interest in remote stand alone photovoltaic power systems. The battery can be protected from damaging overdischarge by using the proper ratio of pilot cell capacities to main battery capacity
Error in total ozone measurements arising from aerosol attenuation
A generalized least squares method for deducing both total ozone and aerosol extinction spectrum parameters from Dobson spectrophotometer measurements was developed. An error analysis applied to this system indicates that there is little advantage to additional measurements once a sufficient number of line pairs have been employed to solve for the selected detail in the attenuation model. It is shown that when there is a predominance of small particles (less than about 0.35 microns in diameter) the total ozone from the standard AD system is too high by about one percent. When larger particles are present the derived total ozone may be an overestimate or an underestimate but serious errors occur only for narrow polydispersions
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