Search results for "Rodin"
showing 10 items of 101 documents
Sinergia tra mappe di qualità delle acque e correnti superficiali nella determinazione strutture di circolazione
2014
La mappatura delle variabili di qualità delle acque, quali la clorofilla-a (CHL-a) e la Temperatura Superficiale del mare (SST-Sea Surface Temperature) viene effettuata routinariamente dai sensori satellitari per l’osservazione della terra. I satelliti forniscono una visione sinottica di questi parametri, praticamente in tempo reale e su larga scala. Ad ogni modo, le relazioni tra i parametri di qualità delle acque e le forzanti fisiche che ne determinano le variabilità spazio-temporali, quali campi di vento e di correnti, necessitano uno studio approfondito.
Spectral evolution of flaring blazars from numerical simulations
2016
High resolution Very Long Baseline Interferometry (VLBI) observations of Active Galactic Nuclei (AGN) revealed traveling and stationary or quasi-stationary radio-components in several blazar jets. The traveling ones are in general interpreted as shock waves generated by pressure perturbations injected at the jet nozzle. The stationary features can be interpreted as recollimation shocks in non-pressure matched jets if they show a quasi-symmetric bump in the spectral index distribution. In some jets there may be interactions between the two kinds of shocks. These shock--shock interactions are observable with VLBI techniques, and their signature should also be imprinted on the single--dish lig…
Piemaisījumu difūzijas caur šķidra silīcija dinamisku brīvu virsmu pētīšana
2018
Pēdējos gados arvien pieaug pieprasījums pēc augstas (99.9999%) tīrības jeb solāras kvalitātes silīcija, kuru var iegūt, īpaši attīrot šķidru silīciju no tajā esošajiem piemaisījumiem. Šajā nozarē notiek aktīva pētniecība, meklējot veidus, kā attīrīšanas procesu būtu iespējams optimizēt. Šajā darbā tiek pētīta potenciāla iespēja celt piemaisījumu aizvades efektivitāti, uz šķidrā silīcija radot virsmas viļņus. Tādēļ darbā veikti skaitliski aprēķini, kas ļauj konstatēt, kā attīrīšanas gaitā piemaisījumi pamet šķidro silīciju, kā arī ļauj saprast, kāda ietekme uz to ir dažādiem virsmas viļņu parametriem – amplitūdai, frekvencei, viļņa garumam. Izdarot aprēķinus, tiek noskaidrots, ka piemaisīju…
Burbuļu ķēdes magnetohidrodinamiskās plūsmas sadalījums dinamiskajās modās taisnstūrainā traukā
2021
Šis darbs demonstrē dynamic mode decomposition (DMD) analīzes lietderību un potenciālu divfāzu plūsmas analīzei. Tiek demonstrēts izstrādāts DMD algoritms, kas ir labi piemērots lielu, sarežģītu skaitliskās modelēšanas un/vai eksperimentā iegūto datu apstrādei. Tiek apskatīta vertikāla burbuļu ķēdes plūsma, taisnstūrainā traukā, ar šķidro galliju, ar un bez ārēja, statiska horizontāla magnētiska lauka. Magnetohidrodinamiska (MHD) burbuļu plūsma tiek skaitliski modelēta ar galīgo tilpumu (hidrodinamika) un galīgo elementu (elektromagnētisms) metodēm. Tiek apskatīts, kā, mainot burbuļu ieplūdes ātrumu, un magnētiskā lauka stiprumu, tiek ietekmētas burbuļu plūsmas struktūras, un burbuļu astes …
Numerical study of blow-up and stability of line solitons for the Novikov-Veselov equation
2017
International audience; We study numerically the evolution of perturbed Korteweg-de Vries solitons and of well localized initial data by the Novikov-Veselov (NV) equation at different levels of the 'energy' parameter E. We show that as |E| -> infinity, NV behaves, as expected, similarly to its formal limit, the Kadomtsev-Petviashvili equation. However at intermediate regimes, i.e. when |E| is not very large, more varied scenarios are possible, in particular, blow-ups are observed. The mechanism of the blow-up is studied.
The mathematical modeling of the single and ensemble dynamics of magnetic filaments
2016
Biomimētisku sistēmu izmantošana mikrodzinēju un šķidrumu maisītāju izveidei ir aktuāls izpētes objekts mīksto materiālu nozarē. Šiem mērķiem iespējams izmantot magnētiskas stīgas, ko ir viegli kontrolēt mainot ārēja magnētiskā lauka parametrus. Šajā darbā ir izveidots magnētisku stīgu matemātisks modelis, kas ietver gan vērp es, gan hidrodinamisko mijiedarbību ietekmi dažādos tuvinājumos un izveidota praktiska implementācija divu programmatūras bibliotēku formā. Ar izveidotā modeļa palīdzību iegūti rezultāti, kas raksturo individuālu stīgu un stīgu ansambļu dinamika plašā kustību kontrolējošo parametru diapazonā un iegūti jauni rezultāti, kas raksturo feromagnētisku un superparamagnētisku …
In-Cylinder Heat Transfer Determination Using Impulse Response Method with a Two-Dimensional Characterization of the Eroding Surface Thermocouple
2021
Heat transfer from the cylinder of internal combustion engines has been studied for decades, both in motored and fired configurations. Its understanding remains fundamental to the optimization of engine structures and sub-systems due to its direct effect on reliability, thermal efficiency and gaseous emissions. Experimental measurements are usually conducted using fast response surface thermometers, which give the instantaneous cylinder surface temperature. The transient component of heat flux through the cylinder wall was traditionally obtained from a spectral analysis of the surface temperature fluctuation, whereas the steady-state component was obtained from Fourier's law of conduction. …
A Teaching Experience: Aeroelasticity and the Finite Element Method
2015
[EN] The aeroelastic modelling of aircraft structures is a fundamental area for the students of Aerospace Engineering Degree. This subject has a strongly multidisciplinary character and involves other several subjects like mechanics, vibrations, aerodynamics, structural analysis. Consequently, the students find stimulating the challenge of merging their knowledge at different areas. In this paper, a teaching experience on the solution of the aeroelastic problem of a 3D-wing through six different computer tasks is presented. The main objective is to attempt a relatively complex problem using a simple version of the Finite Element Method with only four degrees of freedom. The students begin c…
Relativistic Hydrodynamics and Spectral Evolution of GRB Jets
2017
En la presente tesis hemos estudiado los sistemas progenitores de las erupciones de rayos gamma (ERG, o GRBs por sus siglas en inglés --Gamma-Ray Bursts--) de larga duración mediante modelos numéricos de su evolución dinámica y emisión electromagnética. De todas las posibles clases de eventos, en particular nos centramos en aquellas que muestran una componente prominente de emisión térmica, la cual podría generarse por medio de la interacción de un chorro constituido por plasma relativista con el medio en el que se propaga. La parte central de esta tesis se ha dedicado al modelado de ERG a partir de dos clases diferentes de progenitores: ERG ultra largas dominadas en su espectro de emisión …
Reworking of the Tarim Craton by underplating of mantle plume-derived magmas: Evidence from Neoproterozoic granitoids in the Kuluketage area, NW China
2011
Abstract Most Neoproterozoic granitoids in the Kuluketage area, northern Tarim Craton are characterized by strongly depleted HREE abundances and high Sr/Y and (La/Yb) N ratios, showing typical geochemical features of adakitic rocks. Zircon U–Pb dating of three adakitic plutons yielded Neoproterozoic ages (754 ± 4, 790 ± 3 and 798 ± 3 Ma). The adakitic granitoids exhibit low MgO and TiO 2 contents. Their low Cr, Co and Ni abundances, low ɛ Hf ( t ) values (−21 to −11) and high FeO T /MgO ratios (mostly 2.2–2.9) preclude the possibility of being derived from partial melts of delaminated lower crust. The relatively low ɛ Hf ( t ) values and old Hf two-stage model ages ( T DM 2 = 2 . 42 – 3 .0 …