Search results for "Diffusion"

Long-Lived Luminescence and Slow Carrier Diffusion in Metal Halide Perovskites as a result of Multiple Trapping and De-Trapping by Shallow Non-Quench…

2018

Simulation of Order-Disorder Phenomena and Diffusion in Metallic Alloys

1991

The application of the Monte Carlo method to lattice-statistics problems in metallurgy is reviewed. Examples are given for the prediction of phase diagrams from simple model assumptions for effective interatomic potentials and for the calculation of parameters describing long- and short-range order, ordering energy, etc., both for face-centered cubic (fcc) and body-centered cubic (bcc) lattices. Applications to real systems such as Cu—Au and Fe—Al alloys are discussed.

Implementation of non-local boundary layer schemes in the Regional Atmospheric Modeling System and its impact on simulated mesoscale circulations

2016

This paper proposes the implementation of different non-local Planetary Boundary Layer schemes within the Regional Atmospheric Modeling System (RAMS) model. The two selected PBL parameterizations are the Medium-Range Forecast (MRF) PBL and its updated version, known as the Yonsei University (YSU) PBL. YSU is a first-order scheme that uses non-local eddy diffusivity coefficients to compute turbulent fluxes. It is based on the MRF, and improves it with an explicit treatment of the entrainment. With the aim of evaluating the RAMS results for these PBL parameterizations, a series of numerical simulations have been performed and contrasted with the results obtained using the Mellor and Yamada (M…

Determination of eddy diffusivity in the lowermost stratosphere

2005

[1] We present a 2D-advection-diffusion model that simulates the main transport pathways influencing tracer distributions in the lowermost stratosphere (LMS). The model describes slow diabatic descent of aged stratospheric air, vertical (cross-isentropic) and horizontal (along isentropes) diffusion within the LMS and across the tropopause using equivalent latitude and potential temperature coordinates. Eddy diffusion coefficients parameterize the integral effect of dynamical processes leading to small scale turbulence and mixing. They were specified by matching model simulations to observed CO distributions. Interestingly, the model suggests mixing across isentropes to be more important tha…

Applicazione del metodo Monte Carlo a problemi monodimensionali di conduzione termica stazionaria in sistemi con conducibilità dipendente dalla posiz…

2010

Comparison between Disk Diffusion and Microdilution Methods for Determining Susceptibility of Clinical Fungal Isolates to Caspofungin

2007

ABSTRACT We compared the caspofungin (CAS) susceptibility testing results generated by the disk diffusion (DD) assay with the results of the Clinical and Laboratory Standards Institute (CLSI) broth microdilution (BD) reference method for 106 yeast isolates. The isolates represented 11 different fungal species, including Candida albicans ( n = 50), C. parapsilosis ( n = 10), C. glabrata ( n = 10), C. tropicalis ( n = 10), C. guillermondii ( n = 6), C. rugosa ( n = 5), C. krusei ( n = 5), C. kefyr ( n = 2), C. pelliculosa ( n = 2), Saccharomyces cerevisiae ( n = 3), and Geotrichum candidum ( n = 3). The DD assay was performed in supplemented Mueller-Hinton agar with CAS, which was tested at c…

Evaluation of the Disk Diffusion Method Compared to the Microdilution Method in Susceptibility Testing of Anidulafungin against Filamentous Fungi

2008

ABSTRACT Susceptibility testing of anidulafungin (AFG) against 32 mold isolates showed an excellent correlation between disk diffusion (DD) and broth microdilution methods. Based on our data, a 2-μg disk of AFG and a 24-h reading time might represent the best parameters for AFG DD testing against filamentous fungi.

Geochemical Interactions of Plutonium with Opalinus Clay Studied by Spatially Resolved Synchrotron Radiation Techniques

2017

Plutonium plays an important role within nuclear waste materials because of its long half-life and high radiotoxicity. The aim of this study was to investigate with high spatial resolution the reactivity of the more oxidized forms of Pu(V,VI) within Opalinus Clay (OPA) rock, a heterogeneous, natural argillaceous rock considered as a potential repository host. A combination of synchrotron based X-ray microprobe and bulk techniques was used to study the spatial distribution and molecular speciation of Pu within OPA after diffusion and sorption processes. Microscopic chemical images revealed a pronounced impact of geochemical heterogeneities concerning the reactivity of the natural barrier mat…

Force-induced diffusion in microrheology

2012

We investigate the force-induced diffusive motion of a tracer particle inside a glass-forming suspension when a strong external force is applied to the probe (active nonlinear microrheology). A schematic model of mode-coupling theory introduced recently is extended to describe the transient dynamics of the probe particle, and used to analyze recent molecular-dynamics simulation data. The model describes non-trivial transient displacements of the probe before a steady-state velocity is reached. The external force also induces diffusive motion in the direction perpendicular to its axis. We address the relation between the transverse diffusion coefficient D(perpendicular) and the force-depende…

Evaluation of the antibacterial activity of a new ozonized olive oil against oral and periodontal pathogens.

2018

Background In the present study, the antimicrobial properties of a new ozonized olive oil (O-zone gel) against oral and periodontal pathogens will be evaluated and compared with that of common CHX-based agents. Material and methods O-zone gel was compared with two agents based on chlorhexidine digluconate (CHX): Corsodyl Dental Gel and Plak Gel. A. actinomycetemcomitans, P. intermedia and S. mutans, were selected and the antibacterial capability of the compounds was tested by using direct contact agar diffusion test (DCT) and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) evaluations. Differences between specific means were analyzed by a one-way analysis…