Turbulens áramlások kísérleti vizsgálata = Experimental investigation of turbulent flows

Megvizsgáltuk kétdimenziós nedvesítési és lassú égési frontok viselkedését a terjedési sebesség gyorsabb és lassabb növekedést okozó perturbációi mellett. A perturbáció térben egy oszlop mentén volt lokalizálva. A kísérleti eredményeket összehasonlítottuk mind számítógépes szimulációk, mind átlagtér elméletek eredményeivel. Kiátlagolásával szétválasztottuk a véletlenszerű és átlagos jellemzőit a felületeknek és az utóbbiak segítségével tisztán kimutattuk, hogy a növekedést leíró hatásos Kardar-Parisi-Zhang típusú egyenletben nem-lineáris tagot is figyelembe kell venni, melynek meghatározását megadtuk. Numerikus eljárásokat gyakran alkalmaznak kísérletekből származó digitális képeken. Ezekben az esetekben sűrűn értékelnek ki valamilyen matematikai függvényt egy adott útvonal mentén, pl. vonalintegrál. Ha a függvény egy 1 értékű konstans, akkor a vonalintegrál az útvonal hosszát méri. Sokszor előforduló téveszme, hogy elég finom felbontás esetén az útvonalat alkotó legközelebbi és második legközelebbi képpontok távolságának mérése megfelelő eredményt ad. Megmutattuk, hogy ez nincs így és hogy például egy kör esetén a sugár bizonyos mágikus értékei esetén a hiba minimális lehet. Kidolgoztunk egy eljárást, amely képes a útvonal előzetes ismerete nélkül meghatározni, hogy van-e optimális mérési eljárás, és ha van, akkor milyen mérési paraméterekkel lehet azt megvalósítani. Elkezdtünk egy vizsgálatot az állatok ultrahangos tájékozódásának felbontásának vizsgálatára. Ez az együttműködésben végzett munka jelenleg is folyik. | We have investigated the behavior of slow-combustion and wetting fronts in the presence of a columnar defect with enhanced or reduced driving, and compare them with those of mean-field theory and with computer simulation results. The study of the averaged surface profile clearly demonstrates the existence of a Kardar-Parisi-Zhang-type nonlinear term in the effective evolution equation. Computer simulations, numerical methods frequently deal with analising digital images of experimental data. In such cases measuring some function (i.e. path integral, etc) along a path is a common practice. In the simplest case the measured function is identical to unity and the result is the length of the path. A common misconception is that simply measuring the distance between the nearest or second nearest neighbor pixels of the path provides acceptable result if the resolution is high enough. We demonstrated that this is not the case and for a circle we show that there are some magic radius where the numerical error is minimal. We also provide a novel numerical method to measure the length of a path. This method helps to decide if optimal method exists and to chose the optimal measurement parameters. A study concerning the resolution of the echolocalisation of animals is initiated. This on-going project is not closed yet

Self-Evaluation Applied Mathematics 2003-2008 University of Twente

This report contains the self-study for the research assessment of the Department of Applied Mathematics (AM) of the Faculty of Electrical Engineering, Mathematics and Computer Science (EEMCS) at the University of Twente (UT). The report provides the information for the Research Assessment Committee for Applied Mathematics, dealing with mathematical sciences at the three universities of technology in the Netherlands. It describes the state of affairs pertaining to the period 1 January 2003 to 31 December 2008

Stochastic Resetting and Applications

In this Topical Review we consider stochastic processes under resetting, which have attracted a lot of attention in recent years. We begin with the simple example of a diffusive particle whose position is reset randomly in time with a constant rate $r$, which corresponds to Poissonian resetting, to some fixed point (e.g. its initial position). This simple system already exhibits the main features of interest induced by resetting: (i) the system reaches a nontrivial nonequilibrium stationary state (ii) the mean time for the particle to reach a target is finite and has a minimum, optimal, value as a function of the resetting rate $r$. We then generalise to an arbitrary stochastic process (e.g. L\'evy flights or fractional Brownian motion) and non-Poissonian resetting (e.g. power-law waiting time distribution for intervals between resetting events). We go on to discuss multiparticle systems as well as extended systems, such as fluctuating interfaces, under resetting. We also consider resetting with memory which implies resetting the process to some randomly selected previous time. Finally we give an overview of recent developments and applications in the field.Comment: 68 pages, Topical Review accepted version to appear in Journal of Physics A: Mathematical and Theoretical 202

Excellentia Eminentia Effectio

"In these pages you will learn about the fascinating research endeavors that each of our faculty members is undertaking. We have divided their research into the broad categories of health, sustainability, information, and systems. While we recognize the imperfect nature of categorizing research that, by its very nature may be interdisciplinary or transdisciplinary, we nonetheless believe it will be helpful as a way to see the depth and breadth of our research endeavors within each grouping. As you read the profiles on these pages, I know you will begin to appreciate that, taken as a whole, the research spectrum at Columbia Engineering is exceptional and that, as our professors go about their work, they are at the cusp of making breakthroughs that will have a major impact on the way we live our lives today and tomorrow.

93rd Annual Meeting of the Virginia Academy of Science: Proceedings

Full proceedings of the 93rd Annual Meeting of the Virginia Academy of Science, May 21-23, 2015, James Madison University, Harrisonburg, Virgini

Accommodation requirements for microgravity science and applications research on space station

Scientific research conducted in the microgravity environment of space represents a unique opportunity to explore and exploit the benefits of materials processing in the virtual abscence of gravity induced forces. NASA has initiated the preliminary design of a permanently manned space station that will support technological advances in process science and stimulate the development of new and improved materials having applications across the commercial spectrum. A study is performed to define from the researchers' perspective, the requirements for laboratory equipment to accommodate microgravity experiments on the space station. The accommodation requirements focus on the microgravity science disciplines including combustion science, electronic materials, metals and alloys, fluids and transport phenomena, glasses and ceramics, and polymer science. User requirements have been identified in eleven research classes, each of which contain an envelope of functional requirements for related experiments having similar characteristics, objectives, and equipment needs. Based on these functional requirements seventeen items of experiment apparatus and twenty items of core supporting equipment have been defined which represent currently identified equipment requirements for a pressurized laboratory module at the initial operating capability of the NASA space station

Clemson Graduate School Catalog, 1971-1972

https://tigerprints.clemson.edu/grad_anncmnt/1031/thumbnail.jp