1,065 research outputs found
Anisotropic Strong Coupling Calculation of the Local Electromagnetic Response of High-Tc Superconductors
The electromagnetic response of the CuO2-planes is calculated within a strong
coupling theory using model tight binding bands and momentum dependent pairing
interactions representing spin fluctuations and phonon exchange. The
superconducting state resulting from these interactions has d-wave symmetry.
With phonon exchange included the order parameter amplitude grows rapidly below
Tc at elevated frequencies which leads to improved agreement with the observed
temperature dependence of the penetration depth. Good agreement between theory
and experiment can only be achieved if it is assumed that the strength of the
quasiparticle interaction decreases with temperature in the superconducting
state. The amount of this reduction depends sensitively on the momentum
dependence of the interactions, the energy dispersion and the position of the
Fermi line.Comment: 3 pages, LaTex, to be published in J.Phys.Chem.Solids, 1997, SNS
Conf., Cape Co
Kalibrace modelu pro optimalizaci systému vytápěnà a chlazenàs akumulacà energie do spodnà vody
Building performance simulation (BPS) is a powerful tool to support building and system designers in emulating how orientation, building type, HVAC system etc. interacts the overall building performance. Currently BPS is used only for code compliance in the detailed design, neither to make informed choices between different design options nor for building and/ or system optimization [Wilde, 2004].BPS could/ should be used in a way of indicating design solutions, introducing an uncertainty and sensitivity analysis and building and/ or system optimization. This research is about enhancing the use of BPS in the detailed design by supporting design and system optimization
Technique of uncertainty and sensitivity analysis for sustainable building energy systems performance calculations
Sustainable buildings design process is typical for modeling and simulation usage. The main reason is because there is generally no experience with such buildings and there is lot of new approaches and technical solutions to be used. Computer simulation could be supporting tool in engineering design process and can bring the good way for reducing energy consumption together with optimalization algorithm. For the optimization process we have to know which most sensitive input parametr from many of them has to be investigate. Therefore at first is necessary to perform the sensitivity analysis and find out the "strongest" input parametrs which most affecting the results under observation. Also still the simulation tools are mainly using to predict energy consumption, boiler and chiller loads, indoor air quality, etc. before the building is build. The information about the building envelope, schedule and HVAC components are unclear and can bring large uncertainty in results by setting this inputs to the simulation tools. Paper presents preview of uncertainty and sensitivity analysis. This techniques are shown on case study concretely BESTEST case600 with DRYCOLD climate conditions. Also systems VAV (variable volume of air) and water fancoil system are compared. For this prototype the simulation tool IES was chosen
Me, Myself, and Future Generations: The Role of Affinity and Effectiveness in the Creation of Consumer Environmental Stewardship (CENS)
Policymakers, consumer advocate groups, and researchers agree that consumers need to increase their proenvironmental behaviors if a decent standard of living is to be ensured for future generations. Despite high levels of environmental concern, consumers still refrain from large-scale adoption of proenvironmental behaviors. Social marketers agree that a change in attitudes is not enough to stimulate the necessary behavioral change and are looking for ways to help consumers overcome the costs (e.g., price premiums, inconvenience) that are often associated with proenvironmental behaviors. Currently, consumers often see proenvironmental behavior as a trade-off between short-term personal benefits and longer term collective benefits. The authors contribute to the social marketing literature on proenvironmental behavior by introducing the concept of Consumer Environmental Stewardship (CENS), which centers on the use of intrinsic motivation to stimulate a personal sense of responsibility for the environment. The findings, based on a survey and three experiments, show that the stimulation of consumers’ affinity with future generations (AFGs) and perceived consumer effectiveness (PCE) can help to promote CENS, which in turn raises proenvironmental behaviors. However, this research also shows that increasing levels of AFGs can backfire and result in lower levels of CENS, if consumers experience low levels of PCE
Coherent photon coincidence spectroscopy of single quantum systems
Non-equilibrium photon correlations of coherently excited single quantum
systems can reveal their internal quantum dynamics and provide spectroscopic
access. Here we propose and discuss the fundamentals of a coherent photon
coincidence spectroscopy based on the application of laser pulses with variable
delay and the detection of an time-averaged two-photon coincidence rate. For
demonstration, two simple but important cases, i.e., an exciton - biexciton in
a quantum dot and two coupled quantum emitters, are investigated based on
quantum dynamics simulations demonstrating that this nonlinear spectroscopy
reveals information specific to the particular single quantum system
Integrated silicon qubit platform with single-spin addressability, exchange control and robust single-shot singlet-triplet readout
Silicon quantum dot spin qubits provide a promising platform for large-scale
quantum computation because of their compatibility with conventional CMOS
manufacturing and the long coherence times accessible using Si enriched
material. A scalable error-corrected quantum processor, however, will require
control of many qubits in parallel, while performing error detection across the
constituent qubits. Spin resonance techniques are a convenient path to parallel
two-axis control, while Pauli spin blockade can be used to realize local parity
measurements for error detection. Despite this, silicon qubit implementations
have so far focused on either single-spin resonance control, or control and
measurement via voltage-pulse detuning in the two-spin singlet-triplet basis,
but not both simultaneously. Here, we demonstrate an integrated device platform
incorporating a silicon metal-oxide-semiconductor double quantum dot that is
capable of single-spin addressing and control via electron spin resonance,
combined with high-fidelity spin readout in the singlet-triplet basis.Comment: 10 pages, 4 figure
Occurrence of marine litter along abyssal areas of the Gloria Fracture Zone (NE Atlantic).
Marine litter pollution is a recognized form of anthropogenic
disturbance that affects widely the marine environment,
particularly near the continental margins, although also
present at abyssal and bathyal depths. This study reports the
occurrence of marine litter distribution and abundance in four
abyssal basins along the Gloria fracture zone in the NE
Atlantic. Litter items occurrences were analysed using TV-CTD
video surveys carried out during the multidisciplinary
activities of the R/V Meteor M162 cruise. The surveys reached
depths between 3500-4500m and covered 16 km of seafloor,
between the Terceira ridge and the Madeira-Tore Rise. Litter
items were annotated and categorized by type (i.e., plastic,
fishing gear, metal, glass, other unknown items). Results
revealed that litter was exclusively found on soft sediment
habitats across all areas, i.e. depositional areas, with the
overwhelming dominance of plastics items (71%), such as
plastic containers, cups and bag fragments. Although less
common (6-8%), metal, glass and lost fishing gear were also
observed. Litter density was on average 9 times higher in the
easternmost area near the Madeira-Tore ridge, when
compared to the other areas. Higher litter densities are likely
explained due to the proximity to the Madeira-Tore
seamount complex targeted by the fishing industry and
nearimportant corridors of marine traffic between various
Atlantic and Mediterranean locations
The benthic carbon mineralization on a global scale
In this study we present a global distribution pattern and budget of the minimum flux of particulate organic carbon to the sea floor (JPOCα). The estimations are based on regionally specific correlations between the diffusive oxygen flux across the sediment-water interface, the total organic carbon content in surface sediments, and the oxygen concentration in bottom waters. For this, we modified the principal equation of Cai and Reimers [1995] as a basic monod reaction rate, applied within 11 regions where in situ measurements of diffusive oxygen uptake exist. By application of the resulting transfer functions to other regions with similar sedimentary conditions and areal interpolation, we calculated a minimum global budget of particulate organic carbon that actually reaches the sea floor of ∼0.5 GtC yr−1 (>1000 m water depth (wd)), whereas approximately 0.002–0.12 GtC yr−1 is buried in the sediments (0.01–0.4% of surface primary production). Despite the fact that our global budget is in good agreement with previous studies, we found conspicuous differences among the distribution patterns of primary production, calculations based on particle trap collections of the POC flux, and JPOCα of this study. These deviations, especially located at the southeastern and southwestern Atlantic Ocean, the Greenland and Norwegian Sea and the entire equatorial Pacific Ocean, strongly indicate a considerable influence of lateral particle transport on the vertical link between surface waters and underlying sediments. This observation is supported by sediment trap data. Furthermore, local differences in the availability and quality of the organic matter as well as different transport mechanisms through the water column are discussed
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