Search results for "MT"
showing 10 items of 2759 documents
Sun Induced Fluorescence Calibration and Validation for Field Phenotyping
2018
Reliable measurements of Sun Induced Fluorescence (SIF) require a good instrument characterization as well as a complex processing chain. In this paper, we summarize the state of the art SIF retrieval methods and measurements platforms for field phenotyping. Furthermore, we use HyScreen, hyperspectral-imaging system for top of canopy measurements of SIF, as an example of the instrument requirements, data process, and data validation needed to obtain reliable measurements of SIF.
Etude numérique d'équations aux dérivées partielles non linéaires et dispersives
2011
Numerical analysis becomes a powerful resource in the study of partial differential equations (PDEs), allowing to illustrate existing theorems and find conjectures. By using sophisticated methods, questions which seem inaccessible before, like rapid oscillations or blow-up of solutions can be addressed in an approached way. Rapid oscillations in solutions are observed in dispersive PDEs without dissipation where solutions of the corresponding PDEs without dispersion present shocks. To solve numerically these oscillations, the use of efficient methods without using artificial numerical dissipation is necessary, in particular in the study of PDEs in some dimensions, done in this work. As stud…
Zvaigžņotā Debess: 2015, Vasara (228)
2015
Latvijas Universitāte
Thermal analysis applied to the characterization of degradation in soil of polylactide: I. Calorimetric and viscoelastic analyses
2010
[EN] An accelerated soil burial test has been performed on a commercial polylactide (PLA) for simulating non-controlled disposal. Degradation in soil promotes physical and chemical changes in polylactide properties, which can be characterized by Thermal Analysis techniques. Physical changes occurred in polylactide due to the degradation in soil were evaluated by correlating their calorimetric and visco-elastic properties. It is highly remarkable that each calorimetric scan offers specific and enlightening information. Degradation in soil affects the polylactide chains reorganization. A multimodal melting behavior is observed for buried PLA, degradation in soil also promotes the enlarging th…
Density gradient expansion of correlation functions
2013
We present a general scheme based on nonlinear response theory to calculate the expansion of correlation functions such as the pair-correlation function or the exchange-correlation hole of an inhomogeneous many-particle system in terms of density derivatives of arbitrary order. We further derive a consistency condition that is necessary for the existence of the gradient expansion. This condition is used to carry out an infinite summation of terms involving response functions up to infinite order from which it follows that the coefficient functions of the gradient expansion can be expressed in terms the local density profile rather than the background density around which the expansion is ca…
Le Dessoubre: barrière ou trait d'union?
1998
Le Dessoubre n'est qu'une petite rivière dans l'espace franc-comtois. Née essentiellement d'écoulements souterrains à travers les plateaux calcaires de Maîche, Belleherbe et Orchamps-Vennes, elle développe un cours d'un peu plus de 30 kilomètres avant de se jeter dans le Doubs au niveau de Saint-Hippolyte. L'épaisseur des calcaires détermine deux unités paysagères : les plateaux animés par des formes lourdes, la vallée du Dessoubre et de son affluent la Reverotte, coup de scie brutal mais d'ampleur assez modeste, identifiant autour d'elle des espaces montagnards isolés par la raideur des versants.
Simple and sensitive reversed-phase liquid chromatographic assay for analysis of chlorthalidone in urine
1993
Abstract This study describes a rapid method for the determination of chlorthalidone in human urine by reversed-phase liquid chromatography and UV detection at 230 nm, after clean-up over a C8 solid-phase extraction column. Liquid chromatography was carried out on a C18-bonded phase using acetonitrile-phosphate buffer (pH=3) gradient elution. Triamterene was used as internal standard. The system has been applied to the determination of chlorthalidone in the 0.10–10.0 μg/mL concentration interval; the limit of detection was 6 ng/mL.
Klimt artwork: red-pigment material investigation by backscattering Fe-57 Mössbauer spectroscopy, SEM and p-XRF
2017
Material tests were performed on a rediscovered Klimt-artwork "Trompetender Putto". We performed studies on the red colored spots, mainly taken from non-restored parts. MIMOS II Fe-57 Mossbauer spectroscopy (novelty in art-pigment analysis) mainly reveals haematite and crystallized goethite in red colors. Electron microscopy can identify various layers of the original and overpainting of an artwork. The number of layers fluctuates between three and four chemically painted areas. The portable X-ray fluorescence analysis enables to reduce the pigment list to containing mercury (cinnabar), lead, zinc, iron and titanium. Infrared-light-irradiation visualizes the different age of the pigments.
Femtosecond laser induced breakdown spectroscopy of air–methane mixtures
2013
Abstract Femtosecond laser pulses are used in order to induce dielectric breakdown in gaseous mixtures, namely in some reactive air–methane mixtures. The light emitted from the laser induced plasma was analyzed while the main emission features are identified and assigned. From the analysis of the emission spectra, a linear relationship was found to hold between the intensity of some spectral features and methane content. Finally, the use of femtosecond laser induced breakdown as a tool for the in situ determination of the composition of gaseous mixtures (e.g., equivalence ratio) is also discussed.
On critical behaviour in generalized Kadomtsev-Petviashvili equations
2016
International audience; An asymptotic description of the formation of dispersive shock waves in solutions to the generalized Kadomtsev–Petviashvili (KP) equation is conjectured. The asymptotic description based on a multiscales expansion is given in terms of a special solution to an ordinary differential equation of the Painlevé I hierarchy. Several examples are discussed numerically to provide strong evidence for the validity of the conjecture. The numerical study of the long time behaviour of these examples indicates persistence of dispersive shock waves in solutions to the (subcritical) KP equations, while in the supercritical KP equations a blow-up occurs after the formation of the disp…