1,150 research outputs found
System Energy Assessment (SEA), Defining a Standard Measure of EROI for Energy Businesses as Whole Systems
A more objective method for measuring the energy needs of businesses, System
Energy Assessment (SEA), identifies the natural boundaries of businesses as
self-managing net-energy systems, of controlled and self-managing parts. The
method is demonstrated using a model Wind Farm case study, and applied to
defining a true physical measure of its energy productivity for society
(EROI-S), the global ratio of energy produced to energy cost. The traceable
needs of business technology are combined with assignable energy needs for all
other operating services. That serves to correct a large natural gap in energy
use information. Current methods count traceable energy receipts for technology
use. Self-managing services employed by businesses outsource their own energy
needs to operate, and leave no records to trace. Those uncounted energy demands
are often 80% of the total embodied energy of business end products. The scale
of this "dark energy" was discovered from differing global accounts, and
corrected so the average energy cost per dollar for businesses would equal the
world average energy use per dollar of GDP. Presently the energy needs of paid
services that outsource their own energy needs are counted for lack of
information to be "0". Our default assumption is to treat them as "average".
The result is to assign total energy use and impacts to the demand for energy
services, for a "Scope 4" GHG assessment level. Counting only the energy uses
of technology understates the energy needs of business services, as if services
were more energy efficient than technology. The result confirms a similar
finding by Hall et. al. in 1981 [9]. We use exhaustive search for what a
business needs to operate as a whole, locating a natural physical boundary for
its working parts, to define businesses as physical rather than statistical
subjects of science. :measurement, natural systemsComment: 33 pages, 15 figures, accepted as part of pending special issue on
EROI organized by Charlie Hall for Sustainability (MDPI
Models Learning Change
We live in a complex world, made more complex by the difficulty of distinguishing between our cultural ideas of how things work and the independent physical systems of our world we interact with. Environmental systems are hard to recognize and constantly change their behavior independent of what people think about them. So rules for them we've come to trust can become misleading without notice. Learning how to know when natural system realities are changing, and models will need to change with them, starts with identifying the difference between natural physical systems and our cultural ideas of them, between information and its subjects. The leverage used for doing that is the distinctly different way information models and physical systems use energy, are organized, and display different kinds of limits. Environmental systems often have independent learning parts, for example, and models can't. A useful method for identifying individual environmental systems and tracking their independent changes is found in how the conservation of energy requires developmental processes with a recognizable complex continuity, that does not apply to information models. The characteristic continuities of developmental processes can be identified from recorded measures or implied by models of physical systems, and prompt key questions about approaching changes in organization precipitated by changes in scale, that will require finding new variables or concepts for related models. It builds a new bridge of methodology between theoretical and physical systems, introducing a new kind of empirical research. An example of steering economic systems and their models is used, pertaining to the timing of responses to limits of growth and its feasibility.
Gas Kinematics and Excitation in the Filamentary IRDC G035.39-00.33
Some theories of dense molecular cloud formation involve dynamical
environments driven by converging atomic flows or collisions between
preexisting molecular clouds. The determination of the dynamics and physical
conditions of the gas in clouds at the early stages of their evolution is
essential to establish the dynamical imprints of such collisions, and to infer
the processes involved in their formation. We present multi-transition 13CO and
C18O maps toward the IRDC G035.39-00.33, believed to be at the earliest stages
of evolution. The 13CO and C18O gas is distributed in three filaments
(Filaments 1, 2 and 3), where the most massive cores are preferentially found
at the intersecting regions between them. The filaments have a similar
kinematic structure with smooth velocity gradients of ~0.4-0.8 km s-1 pc-1.
Several scenarios are proposed to explain these gradients, including cloud
rotation, gas accretion along the filaments, global gravitational collapse, and
unresolved sub-filament structures. These results are complemented by HCO+,
HNC, H13CO+ and HN13C single-pointing data to search for gas infall signatures.
The 13CO and C18O gas motions are supersonic across G035.39-00.33, with the
emission showing broader linewidths toward the edges of the IRDC. This could be
due to energy dissipation at the densest regions in the cloud. The average H2
densities are ~5000-7000 cm-3, with Filaments 2 and 3 being denser and more
massive than Filament 1. The C18O data unveils three regions with high CO
depletion factors (f_D~5-12), similar to those found in massive starless cores.Comment: 20 pages, 14 figures, 6 tables, accepted for publication in MNRA
Overture - Object-oriented tools for overset grid applications
The Overture framework is an object-oriented environment for solving partial differential equations in two and three space dimensions. It is a collection of C++ libraries that enables the use of finite difference and finite volume methods at a level that hides the details of the associated data structures. Overture can be used to solve problems in complicated, moving geometries using the method of overlapping grids. It has support for grid generation, difference operators, boundary conditions, data-base access and graphics. Short sample code segments are presented to show the power of this approach
Numerical shock propagation using geometrical shock dynamics
A simple numerical scheme for the calculation of the motion of shock waves in gases based on Whitham's theory of geometrical shock dynamics is developed. This scheme is used to study the propagation of shock waves along walls and in channels and the self-focusing of initially curved shockfronts. The numerical results are compared with exact and numerical solutions of the geometrical-shock-dynamics equations and with recent experimental investigations
Biological removal of hydrogen sulfide from refinery wastewater and conversion to elemental sulfur.
The use of the green sulfur bacterium Chlorobium limnicola forma specialis thiosulfatophilum in a bioreactor is proposed as a means of removing hydrogen sulfide from process water and producing elemental sulfur. For petroleum refineries, this is an alternative to sour water stripping followed by the Claus process. The analytical methods that were found to work without interference from other sulfur species were: methylene blue for sulfide, cyanide for elemental sulfur and turbidimetric for sulfate. Elemental Sulfur was successfully produced from sodium sulfide in a batch reactor by C. thiosulfatophilum. From 1 to 90% of the sulfide consumed was recovered as elemental sulfur. There was a mild correlation between the initial pH and the percent recovery of sulfur. The specific growth rate of C. thiosulfatophilum was found to be higher than that found in previous work. The Haldane equation for substrate inhibition was used to calculate the maximum specific growth rate as 0.45 h\sp{-1}. The maximum tolerable level of sulfide was found to be 300 mg/L. The highest rate of substrate utilization was found to be 17.3 mg/Lh.Dept. of Civil and Environmental Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1990 .H457. Source: Masters Abstracts International, Volume: 30-03, page: 0821. Chairman: G. Abdel-Sayed. Thesis (M.A.Sc.)--University of Windsor (Canada), 1990
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Tracer concentration profiles measured in central London as part of the REPARTEE campaign
There have been relatively few tracer experiments carried out that have looked at vertical plume spread in urban areas. In this paper we present results from two tracer (cyclic perfluorocarbon) experiments carried out in 2006 and 2007 in central London centred on the BT Tower as part of the REPARTEE (Regent’s Park and Tower Environmental Experiment) campaign. The height of the tower gives a unique opportunity to study vertical dispersion profiles and transport times in central London. Vertical gradients are contrasted with the relevant Pasquill stability classes. Estimation of lateral advection and vertical mixing times are made and compared with previous measurements. Data are then compared with a simple operational dispersion model and contrasted with data taken in central London as part of the DAPPLE campaign. This correlates dosage with non-dimensionalised distance from source. Such analyses illustrate the feasibility of the use of these empirical correlations over these prescribed distances in central London
High-frequency urban measurements of molecular hydrogen and carbon monoxide in the United Kingdom
High-frequency measurements of atmospheric molecular hydrogen (H<sub>2</sub>) and carbon monoxide (CO) were made at an urban site in the United Kingdom (UK) from mid-December, 2008 until early March, 2009. Very few measurements of H<sub>2</sub> exist in the urban environment, particularly within the UK, but are an essential component in the assessment of anthropogenic emissions of H<sub>2</sub> and to a certain extent CO. These data provide detailed information on urban time-series, diurnal cycles as well as sources and sinks of both H<sub>2</sub> and CO at urban locations. High-frequency data were found to be strongly influenced by local meteorological conditions of wind speed and temperature. Diurnal cycles were found to follow transport frequency very closely due to the sites proximity to major carriageways, consequently a strong correlation was found between H<sub>2</sub> and CO mole fractions. Background subtracted mean and rush hour molar H<sub>2</sub>/CO emission ratios of 0.53±0.08 and 0.57±0.06 respectively, were calculated from linear fitting of data. The scatter plot of all H<sub>2</sub> and CO data displayed an unusual two population pattern, thought to be associated with a large industrial area 85 km to the west of the site. However, the definitive source of this two branch pattern could not be fully elucidated. H<sub>2</sub> emissions from transport in the UK were estimated to be 188±39 Gg H<sub>2</sub>/yr, with 8.1±2.3 Tg/yr of H<sub>2</sub> produced from vehicle emissions globally. H<sub>2</sub> and CO deposition velocities were calculated during stable night-time inversion events when a clear decay of both species was observed. CO was found to have a much higher deposition velocity than H<sub>2</sub>, 1.3±0.8&times;10<sup>−3</sup> and 2.2±1.5&times;10<sup>&minus;4</sup> m s<sup>−1</sup> (1&sigma;) respectively, going against the law of molecular diffusivity. The source of this unusual result was investigated, however no conclusive explanation was found for increased loss of CO over H<sub>2</sub> during stable night time inversion events
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