558 research outputs found
Intercomparison of 3D turbulence parameterizations for dispersion models in complex terrain derived from a circulation model
A procedure for estimating 3D turbulent parameters from the outputs of a circulation model to be used as input of a random flight model for complex terrain dispersion simulation is presented. It is based on parameterization schemes for surface layer parameters and wind velocity standard deviation profiles available in the literature. The predictions of various schemes (two for surface layer quantities and three either for the PBL depth or standard deviation profiles) have been compared to observations carried out in the alpine region (south Switzerland) during
the second TRANSALP campaign by three Doppler Sodar and two sonic anemometers
Two-Point Versus Multipartite Entanglement in Quantum Phase Transitions
We analyze correlations between subsystems for an extended Hubbard model
exactly solvable in one dimension, which exhibits a rich structure of quantum
phase transitions (QPTs). The T=0 phase diagram is exactly reproduced by
studying singularities of single-site entanglement. It is shown how comparison
of the latter quantity and quantum mutual information allows one to recognize
whether two-point or shared quantum correlations are responsible for each of
the occurring QPTs. The method works in principle for any number D of degrees
of freedom per site. As a by-product, we are providing a benchmark for direct
measures of bipartite entanglement; in particular, here we discuss the role of
negativity at the transition.Comment: 4 pages, 2 figures, 1 tabl
An intercomparison of two turbulence closure schemes and four parameterizations for stochastic dispersion models
Two Lagrangian particle models, developed by Luhar and Britter (Atmos. Environ., 23 (1989) 1191) and Weil (J. Atmos. Sci., 47 (1990) 501), satisfying the âwell-mixedâ condition as prescribed by Thomson (J. Fluid. Mech., 180 (1987) 529), are compared. They differ in the closure scheme used in calculating the probability density function of the random forcing in a convective boundary layer. Four different turbulent parameterizations were used as input to both models. Their performances are evaluated against one of the well-known Willis and Deardorff water tank experiments (Atmos. Environ., 12 (1978) 1305). Predicted and measured ground-level concentrations (g.l.c.), maximum g.l.c. distance, mean plume height and plume vertical spread are presented and discussed
Single-site entanglement at superconductor-insulator transition in the Hirsch model
We investigate the transition to the insulating state in the one-dimensional
Hubbard model with bond-charge interaction x (Hirsch model), at half-filling
and T=0. By means of the density-matrix renormalization group algorithm the
charge gap closure is examined by both standard finite size scaling analysis
and looking at singularities in the derivatives of single-site entanglement.
The results of the two techniques show that a quantum phase transition takes
place at a finite Coulomb interaction u_c(x) for x>0.5. The region 0<u<u_c
turns out to have a superconducting nature, at least for not too large x>x_c.Comment: 5 pages, 6 figure
Ten years of lateral flow immunoassay technique applications: Trends, challenges and future perspectives
The Lateral Flow Immunoassay (LFIA) is by far one of the most successful analytical platforms to perform the on-site detection of target substances. LFIA can be considered as a sort of lab-in-a-hand and, together with other point-of-need tests, has represented a paradigm shift from sample-to-lab to lab-to-sample aiming to improve decision making and turnaround time. The features of LFIAs made them a very attractive tool in clinical diagnostic where they can improve patient care by enabling more prompt diagnosis and treatment decisions. The rapidity, simplicity, relative cost-effectiveness, and the possibility to be used by nonskilled personnel contributed to the wide acceptance of LFIAs. As a consequence, from the detection of molecules, organisms, and (bio)markers for clinical purposes, the LFIA application has been rapidly extended to other fields, including food and feed safety, veterinary medicine, environmental control, and many others. This review aims to provide readers with a 10-years overview of applications, outlining the trends for the main application fields and the relative compounded annual growth rates. Moreover, future perspectives and challenges are discussed
MICROSPRAY SIMULATION OF DENSE GAS DISPERSION IN COMPLEX TERRAIN
An extended validation of the new Lagrangian particle model MicroSpray version for dense gas simulation is proposed.
MicroSpray simulates the dense gas dispersion in situations characterized by the presence of buildings, other obstacles, complex
terrain, and possible occurrence of low wind speed conditions. Its performances are compared to a chlorine railway accident
(Macdona), to a field experiment (Kit Fox) and to an atmospheric CFD model
NanoMIP-based solid phase extraction of fluoroquinolones from human urine: A proof-of-concept study
NanoMIPs that are prepared by solid phase synthesis have proven to be very versatile, but to date only limited attention has been paid to their use in solid phase extraction. Thus, since nanoMIPs show close similarities, in terms of binding behavior, to antibodies, it seems relevant to verify if it is possible to use them as mimics of the natural antibodies that are used in immunoextraction methods. As a proof-of-concept, we considered prepared nanoMIPs against fluoroquinolone ciprofloxacin. Several nanoMIPs were prepared in water with polymerization mixtures of different compositions. The polymer with the highest affinity towards ciprofloxacin was then grafted onto a solid support and used to set up a solid phase extractionâHPLC method with fluorescence detection, for the determination of fluoroquinolones in human urine. The method resulted in successful selection for the fluoroquinolone antibiotics, such that the nanoMIPs were suitable for direct extraction of the antibiotics from the urine samples at the ”g mLâ1 level. They required no preliminary treatment, except for a 1 + 9 (v/v) dilution with a buffer of pH 4.5 and they had good analyte recovery rates; up to 85% with precision in the range of 3 to 4.5%, without interference from the matrix. These experimental results demonstrate, for the first time, the feasibility of the use of nanoMIPs to develop solid phase extraction methods
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