Search results for "Propagation"
showing 10 items of 676 documents
Data Treatment and Error Analysis in Kinetics
2000
Methods of data treatment in kinetics are reviewed from a practical viewpoint. The equations to describe the kinetics of chemical reactions and the methodology to obtain the models are presented. Moreover, the integration methods that are needed for the simulation of complex reactions are explained, from the simple first-order reaction to the complex general mechanism. However, it is essential to know the main sources of error in data treatment in order to reduce their effects on the results. Stress is put on the analysis of the errors due to the simplification of complex models. The different factors that influence the kinetics of the reaction are reviewed. How to take advantage of the kin…
Near-Real-Time Estimation of Water Vapor Column From MSG-SEVIRI Thermal Infrared Bands: Implications for Land Surface Temperature Retrieval
2015
The Meteosat Second Generation-Spinning Enhanced Visible and Infrared Imager (MSG-SEVIRI) instrument provides observations of half the globe every 15 min, at low spatial resolution. These data are an invaluable tool to observe daily to yearly cycle of land surface temperature (LST), as well as for various early warning systems. However, advanced algorithms for LST estimation requires a previous estimation of the water vapor (WV) column above the observed pixel, for which no instantaneous retrieval methods are yet available, and therefore hinders their implementation in a near-real-time processing chain for MSG-SEVIRI data. This work analyzes three different formulations for such WV retrieva…
Charge dynamics in molecular junctions: nonequilibrium Green's function approach made fast
2014
Real-time Green's function simulations of molecular junctions (open quantum systems) are typically performed by solving the Kadanoff-Baym equations (KBE). The KBE, however, impose a serious limitation on the maximum propagation time due to the large memory storage needed. In this work we propose a simplified Green's function approach based on the Generalized Kadanoff-Baym Ansatz (GKBA) to overcome the KBE limitation on time, significantly speed up the calculations, and yet stay close to the KBE results. This is achieved through a twofold advance: first we show how to make the GKBA work in open systems and then construct a suitable quasi-particle propagator that includes correlation effects …
Hyperconcentrated flow and men velocity estimation: a study case
2015
Due to the complexity of the debris-flow process, numerical models to simulate propagation phenomenon are still limited. Different approaches (either monophase or two-phase) have been proposed in literature to solve the set of governing equations. But, the difficulty is due to the fact that these equations require suitable closure relations that should be valid in a very wide range of slope and materials characteristics. The point is that, in order to perform a hazard assessment and/or to design protective measures against debris flows, it is necessary to estimate important parameters such as mean flow velocity, peak discharge and runout distance. Experimental program has been recently cond…
Transcriptomic and proteomic insights of the wine yeast biomass propagation process
2010
Transcriptome and proteome profiles have been established for the commercial wine yeast strain T73 during an important industrial process: yeast biomass propagation. The data from both analyses reveal that the metabolic transition from fermentation to respiration is the most critical step in biomass propagation. We identified 177 ORFs and 56 proteins among those most expressed during the process, thus highlighting cell stress response, mitochondrial and carbohydrate metabolism as the most represented functional categories. A direct correlation between mRNA changes and protein abundance was observed for several functional categories such as tricarboxylic acid cycle proteins, heat shock prote…
Analytical calculation of the Peierls-Nabarro barriers for the Remoissenet-Peyrard substrate potential
1999
We derive analytically the pinning potential and the pinning barrier of kinks due to discreteness of lattices for the Remoissenet-Peyrard substrate potential by means of the residue method. The theoretical analysis in the low discreteness effect regime is compared in detail with numerical results of Peyrard and Remoissenet [Phys. Rev. B 26, 2886 (1982)], yielding a very satisfactory agreement.
RSS-eye: Human-assisted Indoor Localization without Radio Maps
2015
The pervasive diffusion of smartphones is boosting indoor positioning solutions and location-based services. We propose a novel methodology to perform indoor positioning of mobile users by the estimation of angles of arrival from access points whose locations are known. Angles of arrival are estimated by correlating WiFi RSSI measurements with data coming from a digital compass, which is provided by most current handsets. Our system has minimal requirements in terms of infrastructure and mobile hardware. The system neither needs calibration, nor radio maps but requires the user to perform a gesture when an estimation is needed. The resulting on-demand localization has advantages in terms of…
River water quality assessment: a hydrodynamic water quality model for propagation of pollutants
2010
A hydrodynamic river water quality model is presented. The model consists of a quantity and a quality sub-model. The quantity sub-model is based on the Saint Venant equations. The solution of the Saint Venant equations is obtained by means of an explicit scheme based on space-time conservation. The method considers the unification of space and time and the enforcement of flux conservation in both space and time. On the other hand the quality sub-model is based on the advection dispersion equation. Particularly, the principle of upstream weighting applied to finite difference methods is employed. Such a method enables us to reduce the numerical dispersion, avoiding oscillation phenomenon. Th…
Solving ultrasonic ray tracing in parts with multiple material layers through Root-Finding methods
2022
Ultrasonic testing has been used for material analysis and inspection since 1930's. Nevertheless, the applicability of ultrasonic waves to new complex cases is still growing, thanks to the availability of powerful electronics and software. However, the complication that slows down the deployment of ultrasonic inspection to geometric complex parts and structures arises from the wave refraction phenomenon. A clear understanding of the ultrasound wave propagation, impacted by refractions, is crucial to interpret the data obtained from the inspection of multi-layered/multi-medium test subjects as it is not always possible to assume that mechanical waves travel in straight lines. This work prese…
In vitro Shoot Regeneration from Flower and Leaf Explants in Rhododendron
2003
Rhododendron shoot regeneration was accomplished using either flower explants (each consisting of ovary with pedicel) of Rhododendron cvs. Nova Zembla and Irina or leaves isolated from in vitro grown Rhododendron catawbiense Michx. Multiple shoot tip clumps were obtained on Anderson's medium containing 0.5 to 1.5 mg dm−3 thidiazuron (TDZ) in combination with 12 to 15 mg dm−3 N6-[2-isopentenyl]adenine (2iP) and 1 to 3 mg dm−3 indole-3-butyric acid (IBA). After 16 weeks on the regeneration media, explants with shoot tip clumps were transferred for shoot elongation to Anderson's medium with 3 mg dm−3 2iP. Two months later, the shoots have reached 5 to 40 mm in length and were fit for subcultiv…