705 research outputs found
Stochastic evaluation of sewer inlet capacity on urban pluvial flooding
In this paper we present an innovative methodology to stochastically assess the impact of sewer inlet conditions on urban pluvial flooding. The results showed that sewer inlet capacity can have a large impact on the occurrence of urban pluvial flooding. The methodology is a useful tool for dealing with uncertainties in sewer inlet operational conditions and contribute to comprehensive assessment of urban pluvial risk assessment
Stochastic urban pluvial flood hazard maps based upon a spatial-temporal rainfall generator
It is a common practice to assign the return period of a given storm event to the urban pluvial flood event that such storm generates. However, this approach may be inappropriate as rainfall events with the same return period can produce different urban pluvial flooding events, i.e., with different associated flood extent, water levels and return periods. This depends on the characteristics of the rainfall events, such as spatial variability, and on other characteristics of the sewer system and the catchment. To address this, the paper presents an innovative contribution to produce stochastic urban pluvial flood hazard maps. A stochastic rainfall generator for urban-scale applications was employed to generate an ensemble of spatially—and temporally—variable design storms with similar return period. These were used as input to the urban drainage model of a pilot urban catchment (~9 km2) located in London, UK. Stochastic flood hazard maps were generated through a frequency analysis of the flooding generated by the various storm events. The stochastic flood hazard maps obtained show that rainfall spatial-temporal variability is an important factor in the estimation of flood likelihood in urban areas. Moreover, as compared to the flood hazard maps obtained by using a single spatially-uniform storm event, the stochastic maps generated in this study provide a more comprehensive assessment of flood hazard which enables better informed flood risk management decisions
Entanglement for all quantum states
It is shown that a state that is factorizable in the Hilbert space
corresponding to some choice of degrees of freedom, becomes entangled for a
different choice of degrees of freedom. Therefore, entanglement is not a
special case but is ubiquitous in quantum systems. Simple examples are
calculated and a general proof is provided. The physical relevance of the
change of tensor product structure is mentioned.Comment: 9 page
Probing a spin transfer controlled magnetic nanowire with a single nitrogen-vacancy spin in bulk diamond
The point-like nature and exquisite magnetic field sensitivity of the
nitrogen vacancy (NV) center in diamond can provide information about the inner
workings of magnetic nanocircuits in complement with traditional transport
techniques. Here we use a single NV in bulk diamond to probe the stray field of
a ferromagnetic nanowire controlled by spin transfer (ST) torques. We first
report an unambiguous measurement of ST tuned, parametrically driven,
large-amplitude magnetic oscillations. At the same time, we demonstrate that
such magnetic oscillations alone can directly drive NV spin transitions,
providing a potential new means of control. Finally, we use the NV as a local
noise thermometer, observing strong ST damping of the stray field noise,
consistent with magnetic cooling from room temperature to 150 K.Comment: 6 pages, 5 figures, plus supplementary informatio
The effect of operational conditions on the hydrodynamic characteristics of the sludge bed in UASB reactors.
Multi-agent system specification for distributed scheduling in home health care
Nowadays, scheduling and allocation of resources and tasks becomes a huge and complex challenge to the most diverse industrial areas, markets, services and health. The problem with current scheduling systems is that their management is still done manually or using classical optimization methods (usually static, time-consuming) and centralized approaches. However, opportunities arise to decentralize solutions with smart systems, which enable the distribution of the computational effort, the flexibility of behaviours and the minimization of operating times and operational planning costs. The paper proposes the specification of a Multi-agent System (MAS) for the Home Health Care (HHC) scheduling and allocation. The MAS technology enables the scheduling of intelligent behaviours and functionalities based on the interaction of agents, and allows the evolution of current strategies and algorithms, as it can guarantee the fast response to condition changes, flexibility and responsiveness in existing planning systems. An experimental HHC case study was considered to test the feasibility and effectiveness of the proposed MAS approach, the results demonstrating promising qualitative and quantitative indicators regarding the efficiency and responsiveness of the HHC scheduling.This work has been supported by FCT—Fundação para a Ciência e a Tecnologia within the R&D Units Projects Scope: UIDB/00319/2020 and UIDB/05757/2020. Filipe Alves is supported by FCT Doctorate Grant Reference SFRH/BD/143745/2019
Hydrodynamic obstruction to bubble expansion
We discuss a hydrodynamic obstruction to bubble wall acceleration during a
cosmological first-order phase transition. The obstruction results from the
heating of the plasma in the compression wave in front of the phase transition
boundary. We provide a simple criterion for the occurrence of the obstruction
at subsonic bubble wall velocity in terms of the critical temperature, the
phase transition temperature, and the latent heat of the model under
consideration. The criterion serves as a sufficient condition of subsonic
bubble wall velocities as required by electroweak baryogenesis.Comment: 18 pages, 4 figures; comments and reference added, published versio
Produção de biogás a partir do glicerol oriundo do biodiesel.
bitstream/item/55346/1/COT11018.pd
Geração de metano a partir de resíduos lignocelulósicos oriundos da produção do biocombustível: revisão.
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