1,597 research outputs found
Processing of combined domestic bath and laundry waste waters for reuse as commode flushing water
An experimental investigation of processes and system configurations for reclaiming combined bath and laundry waste waters for reuse as commode flush water was conducted. A 90-min recycle flow was effective in removing particulates and in improving other physical characteristics to the extent that the filtered water was subjectively acceptable for reuse. The addition of a charcoal filter resulted in noticeable improvements in color, turbidity, and suds elimination. Heating and chlorination of the waste waters were investigated for reducing total organism counts and eliminating coliform organisms. A temperature of 335.9 K (145 F) for 30 min and chlorine concentrations of 20 mg/l in the collection tank followed by 10 mg/l in the storage tank were determined to be adequate for this purpose. Water volume relationships and energy-use rates for the waste water reuse systems are also discussed
The chemical/physical and microbiological characteristics of typical bath and laundry waste waters
Chemical/physical and microbiological characteristics are studied of typical bath and laundry waters collected during a 12 day test in which the untreated waste waters were reused for toilet flush. Most significant changes were found for ammonia, color, methylene blue active substances, phosphates, sodium, sulfates, total organic carbon, total solids, and turbidity in comparison with tap water baseline. The mean total number of microorganisms detected in the waste waters ranged from 1 million to 10 to the 7th power cells/m1 and the mean number of possible coliforms ranged from 10 to the 5th power to 1 million. An accumulation of particulates and an objectible odor were detected in the tankage used during the 12 day reuse of the untreated waste waters. The combined bath and laundry waste waters from a family of four provided 91 percent of the toilet flush water for the same family
Preliminary data for the 20 May 1974, simultaneous evaluation of remote sensors experiment
Several remote sensors were simultaneously used to collect data over the tidal James River from Hopewell to Norfolk, Virginia. Sensors evaluated included the Multichannel-Ocean Color Sensor, multispectral scanners, and multispectral photography. Ground truth measurements and remotely sensed data are given. Preliminary analysis indicates that suspended sediment and concentrated industrial effluent are observable from all sensors
A method of predicting variable speed rail corrugation growth using standard statistical moments
Wear-type rail corrugation is a significant problem in the railway transport industry. Some recent work has suggested that speed control can be used as an effective tool to minimize the rate of corrugation growth. This has brought about the need to model corrugation growth under variable passing speed. Variable speed rail corrugation growth modelling normally consists of either numerical simulation of a sequence of varied speed wheel passes or direct integration of a probabilistic passing speed distribution function; both of which are computationally expensive. This paper investigates the use of the statistical moments of the speed probability density function to greatly improve the computational speed of variable speed corrugation growth models and compares results of changing standard deviation and skewness to numerical integration models. It also identifies the effects of individual statistical moments on corrugation growth to provide better insight into control methods. The new modelling method correlated well with the numerical integration models for small standard deviations in speed (less than 10%) and highlighted a need to consider kurtosis in predicting the performance of speed control based corrugation mitigation schemes. For larger standard deviations in speed, higher than 4th order effects need to be considered
Classical Disordered Ground States: Super-Ideal Gases, and Stealth and Equi-Luminous Materials
Using a collective coordinate numerical optimization procedure, we construct
ground-state configurations of interacting particle systems in various space
dimensions so that the scattering of radiation exactly matches a prescribed
pattern for a set of wave vectors. We show that the constructed ground states
are, counterintuitively, disordered (i.e., possess no long-range order) in the
infinite-volume limit. We focus on three classes of configurations with unique
radiation scattering characteristics: (i)``stealth'' materials, which are
transparent to incident radiation at certain wavelengths; (ii)``super-ideal''
gases, which scatter radiation identically to that of an ensemble of ideal gas
configurations for a selected set of wave vectors; and (iii)``equi-luminous''
materials, which scatter radiation equally intensely for a selected set of wave
vectors. We find that ground-state configurations have an increased tendency to
contain clusters of particles as one increases the prescribed luminosity.
Limitations and consequences of this procedure are detailed.Comment: 44 pages, 16 figures, revtek
Planetary systems around close binary stars: the case of the very dusty, Sun-like, spectroscopic binary BD+20 307
Field star BD+20 307 is the dustiest known main sequence star, based on the
fraction of its bolometric luminosity, 4%, that is emitted at infrared
wavelengths. The particles that carry this large IR luminosity are unusually
warm, comparable to the temperature of the zodiacal dust in the solar system,
and their existence is likely to be a consequence of a fairly recent collision
of large objects such as planets or planetary embryos. Thus, the age of BD+20
307 is potentially of interest in constraining the era of terrestrial planet
formation. The present project was initiated with an attempt to derive this age
using the Chandra X-ray Observatory to measure the X-ray flux of BD+20 307 in
conjunction with extensive photometric and spectroscopic monitoring
observations from Fairborn Observatory. However, the recent realization that
BD+20 307 is a short period, double-line, spectroscopic binary whose components
have very different lithium abundances, vitiates standard methods of age
determination. We find the system to be metal-poor; this, combined with its
measured lithium abundances, indicates that BD+20 307 may be several to many
Gyr old. BD+20 307 affords astronomy a rare peek into a mature planetary system
in orbit around a close binary star (because such systems are not amenable to
study by the precision radial velocity technique).Comment: accepted for ApJ, December 10, 200
The effects of passing speed distribution on rail corrugation growth rate
The transportation phenomenon known as wear-type rail corrugation is a significant problem in railway engineering, which manifests as a periodic wear pattern developing on the surface of the wheel and rail with use. Some field studies and recent theoretical results by the current authors have suggested that uniformity in pass speed causes an increase in corrugation growth rate. This paper presents the predicted change in corrugation growth rate and dominant wavelengths with change in passing speed distribution, based on state of the art cornering growth modelling techniques
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