3,871 research outputs found
Applying uncertainty considerations to energy conservation equations
When applying computer simulation tools in practice uncertainties abound, for example in material properties and boundary conditions. To facilitate the quantification of the effects of uncertainties, the differential, factorial and Monte Carlo methods have been implemented within a simulation tool, ESP-r. These methods require multiple simulations to extract statistical measures of model uncertainty. An alternative approach is to embed uncertainty considerations within the simulation tool's algorithms. The principle advantages of this approach are that the uncertainty is quantified at all times and therefore requires only a single simulation. Coupled with this, it is possible to take control action based on the prevailing effects of uncertainties. This paper details the mathematical techniques required to integrate uncertainty considerations within the energy conservation equations when applied to the simulation of buildings. A comparison is made between the use of this novel approach and traditional mechanisms of assessing uncertainty
Structure of d(TGCGCA)(2) and a comparison with other DNA Hexamers
The X-ray crystal structure of d(TGCGCA)(2) has been determined at 120 K to a resolution of 1.3 Angstrom. Hexamer duplexes, in the Z-DNA conformation, pack in an arrangement similar to the 'pure spermine form' [Egli et al. (1991). Biochemistry, 30, 11388-11402] but with significantly different cell dimensions. The phosphate backbone exists in two equally populated discrete conformations at one nucleotide step, around phosphate 11. The structure contains two ordered cobalt hexammine molecules which have roles in stabilization of both the Z-DNA conformation of the duplex and in crystal packing. A comparison of d(TGCGCA)(2) with other Z-DNA hexamer structures available in the Nucleic Acid Database illustrates the elusive nature of crystal packing. A review of the interactions with the metal cations Na+, Mg2+ and Co3+ reveals a relatively small proportion of phosphate binding and that close contacts between metal ions are common. A prediction of the water structure is compared with the observed pattern in the reported structure
Simulation-assisted control in building energy management systems
Technological advances in real-time data collection, data transfer and ever-increasing computational power are bringing simulation-assisted control and on-line fault detection and diagnosis (FDD) closer to reality than was imagined when building energy management systems (BEMSs) were introduced in the 1970s. This paper describes the development and testing of a prototype simulation-assisted controller, in which a detailed simulation program is embedded in real-time control decision making. Results from an experiment in a full-scale environmental test facility demonstrate the feasibility of predictive control using a physically-based thermal simulation program
Puffed Noncommutative Nonabelian Vortices
We present new solutions of noncommutative gauge theories in which coincident
unstable vortices expand into unstable circular shells. As the theories are
noncommutative, the naive definition of the locations of the vortices and
shells is gauge-dependent, and so we define and calculate the profiles of these
solutions using the gauge-invariant noncommutative Wilson lines introduced by
Gross and Nekrasov. We find that charge 2 vortex solutions are characterized by
two positions and a single nonnegative real number, which we demonstrate is the
radius of the shell. We find that the radius is identically zero in all
2-dimensional solutions. If one considers solutions that depend on an
additional commutative direction, then there are time-dependent solutions in
which the radius oscillates, resembling a braneworld description of a cyclic
universe. There are also smooth BIon-like space-dependent solutions in which
the shell expands to infinity, describing a vortex ending on a domain wall.Comment: 21 pages, 3 eps figures. v2: published version, analytic solution
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Dynamics with Infinitely Many Time Derivatives and Rolling Tachyons
Both in string field theory and in p-adic string theory the equations of
motion involve infinite number of time derivatives. We argue that the initial
value problem is qualitatively different from that obtained in the limit of
many time derivatives in that the space of initial conditions becomes strongly
constrained. We calculate the energy-momentum tensor and study in detail time
dependent solutions representing tachyons rolling on the p-adic string theory
potentials. For even potentials we find surprising small oscillations at the
tachyon vacuum. These are not conventional physical states but rather
anharmonic oscillations with a nontrivial frequency--amplitude relation. When
the potentials are not even, small oscillatory solutions around the bottom must
grow in amplitude without a bound. Open string field theory resembles this
latter case, the tachyon rolls to the bottom and ever growing oscillations
ensue. We discuss the significance of these results for the issues of emerging
closed strings and tachyon matter.Comment: 46 pages, 14 figures, LaTeX. Replaced version: Minor typos corrected,
some figures edited for clarit
Complexity in Prefix-Free Regular Languages
We examine deterministic and nondeterministic state complexities of regular
operations on prefix-free languages. We strengthen several results by providing
witness languages over smaller alphabets, usually as small as possible. We next
provide the tight bounds on state complexity of symmetric difference, and
deterministic and nondeterministic state complexity of difference and cyclic
shift of prefix-free languages.Comment: In Proceedings DCFS 2010, arXiv:1008.127
Real time antimicrobial resistance surveillance in critical care: Identifying outbreaks of carbapenem resistant gram negative bacteria from routinely collected data
Sulfate Foot Baths on Dairies and Crop Toxicities
A rising concern with the application of dairy wastes to agricultural fields is the accumulation of
copper (Cu) in the soil. Copper sulfate (CuSO4) from cattle footbaths is washed out of dairy
barns and into wastewater lagoons. The addition of CuSO4 baths can increase Cu concentration
significantly in manure slurry, from approximately 5.0 grams per 1,000 liters to 90.0 grams per
1,000 liters. The Cu-enriched dairy waste is then applied to agricultural crops, thus raising
concerns about how soils and plants are impacted by these Cu additions
Copper Sulfate Foot Baths on Dairies and Crop Toxicities – What are the Risks?
A rising concern with the application of dairy wastes to agricultural fields is the accumulation of
copper (Cu) in the soil. Copper
sulfate (CuSO4) from cattle foot
baths are washed out of dairy
barns and into wastewater lagoons. The addition of CuSO4
baths has been reported to increase Cu concentration significantly in manure slurry from 4.8
g/1000 L to 88.6 g/1000 L (Miner
Institute, New York). The Cu-enriched dairy waste is then applied to agricultural crops, thus raising concerns about how soils and
plants are impacted by these Cu additions
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