Proračun geometrijske osjetljivosti turbo-profila korištenjem numeričke mehanike fluida i jednadžbi kontinuiranog adjointa

U radu je provedena simulacija strujanja kroz turbinsku rešetku pomoću dvodimenzionalnog modela presjeka lopatica primjenom algoritma SIMPLE uz izračun osjetljivosti ukupnog pada zaustavnog tlaka na promjenu oblika lopatice. Za izračun osjetljivosti obzirom na oblik lopatice korišten je sustav adjungiranih Navier-Stokesovih jednadžbi u k-epsilon modelu turbulencije. Analizirane su dvije geometrije od kojih bi jedna trebala pokazati kako izgleda osjetljivost za dobro konstruirani a druga za loše konstruirani profil. Kvalitetniji je profil konstruiran isključivo pomoću kružnih lukova, dok na manje kvalitetnom profilu osim kružnih lukova, izlazni dio lopatice definiran pravcima Simulacija je provedena u programskom paketu OpenFOAM . Napravljena je također usporedba odražaja dvaju adjungiranih modela turbulencije: adjungirani k-epsilon i "frozen turbulence"

POLITICAL ELECTIONS FOR MARKETERS

SrFe12O19 coatings, intended as electromagnetic wave absorbers, were produced by atmospheric plasma spraying (APS) using two different kindsof feedstock powders: spray-dried agglomerates of micrometric SrFe12O19 particles (type-A) or spray-dried agglomerates of raw materials (SrCO3,Fe2O3), reactively sintered at 1100 ◦C (type-B).During spraying, type-A agglomerates either remain unmelted, producing porous coating regions where crystalline hexaferrite is retained, orare disrupted into smaller granules which melt completely, resulting in dense coating regions with no crystalline hexaferrite.The sintered type-B agglomerates possess higher cohesive strength and do not fall apart: the finer ones melt completely, whereas, in the largerones, the outer region melts and infiltrates the porous unmelted core which retains crystalline hexaferrite. Dense coatings can therefore be obtainedwhile preserving high amounts of crystalline hexaferrite even inside the dense areas. Such coatings show magnetic properties that are promisingfor electromagnetic wave absorption applications

Magneto-optic dynamics in a ferromagnetic nematic liquid crystal

We investigate dynamic magneto-optic effects in a ferromagnetic nematic liquid crystal experimentally and theoretically. Experimentally we measure the magnetization and the phase difference of the transmitted light when an external magnetic field is applied. As a model we study the coupled dynamics of the magnetization, M, and the director field, n, associated with the liquid crystalline orientational order. We demonstrate that the experimentally studied macroscopic dynamic behavior reveals the importance of a dynamic cross-coupling between M and n. The experimental data are used to extract the value of the dissipative cross-coupling coefficient. We also make concrete predictions about how reversible cross-coupling terms between the magnetization and the director could be detected experimentally by measurements of the transmitted light intensity as well as by analyzing the azimuthal angle of the magnetization and the director out of the plane spanned by the anchoring axis and the external magnetic field. We derive the eigenmodes of the coupled system and study their relaxation rates. We show that in the usual experimental set-up used for measuring the relaxation rates of the splay-bend or twist-bend eigenmodes of a nematic liquid crystal one expects for a ferromagnetic nematic liquid crystal a mixture of at least two eigenmodes.Comment: 20 pages, 23 figures, 42 reference

Why implusive behaviour may be good for your health

__Abstract__ Just as we can give in to our oh-so guilty impulses in moments of weakness, new research shows that under the right circumstances these impulses can in fact lead us to engage in behaviour that is actually more conducive to our health

Charism: The Gift That Keeps On Giving

We hear the word “charism” used frequently in Catholic education circles today. Sometimes that word is used and interpreted differently by different people. For some of us, this can make charism difficult to understand. Even when we understand it, it can seem to be something beyond us, something we don’t know how to tap into to enhance the Catholic identity of our school. In this session, we will talk about what charism is, why learning about the particular charism that enlivens your school is important, what you might do if your school is not identified with a particular charism, and how, in some very practical ways, a charism can shape the way things happen in your school every day