571 research outputs found

    Oscillatory Behavior of Critical Amplitudes of the Gaussian Model on a Hierarchical Structure

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    We studied oscillatory behavior of critical amplitudes for the Gaussian model on a hierarchical structure presented by a modified Sierpinski gasket lattice. This model is known to display non-standard critical behavior on the lattice under study. The leading singular behavior of the correlation length Ī¾\xi near the critical coupling K=KcK=K_c is modulated by a function which is periodic in lnā”āˆ£lnā”(Kcāˆ’K)āˆ£\ln|\ln(K_c-K)|. We have also shown that the common finite-size scaling hypothesis, according to which for a finite system at criticality Ī¾\xi should be of the order of the size of system, is not applicable in this case. As a consequence of this, the exact form of the leading singular behavior of Ī¾\xi differs from the one described earlier (which was based on the finite-size scaling assumption).Comment: 9 pages (REVTEX), 2 figures (EPS), Phys. Rev. E (accepted

    Dipole representation of half-filled Landau level

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    We introduce a variant of dipole representation for composite fermions in a half-filled Landau level, taking into account the symmetry under exchange of particles and holes. This is implemented by a special constraint on composite fermion and composite hole degree of freedom (of an enlarged space), that makes the resulting composite particle, dipole, a symmetric object. We study an effective Hamiltonian, that commutes with the constraint on the physical space, and fulfills the requirement for boost invariance on the Fermi level. The calculated Fermi liquid parameter F2 is in a good agreement with numerical investigations in [Phys. Rev. Lett. 121, 147601 (2018)].Comment: 9 pages, 4 figure

    Orthodontic Treatment of Dentofacial Deformities

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    Međučeljusni nesklad stvara velike probleme pacijentima i estetski i funkcionalno. Razlog dolaska pacijenata u Kliniku uglavnom je estetske naravi, jer se radi o mlađim osobama, a funkicionalne su smjetnje u drugome planu. Uzimanje hrane, govor i disanje u takvih su osoba znatno otežani. Prikazat ćemo jedan od slučajeva liječenje kombiniranoga dentofacijalnog deformiteta: PROGNATHISMUS ET LATEROGNATHISMUS MANDIBULARIS. Pacijentica, 34 godine. Iz anamnestičkih podataka nismo saznali da sličnih problema ima u obitelji. Motiv dolaska na Kliniku bio je estetske naravi, premda se je pacijentica žalila na bolove u oba čeljusna zgloba, otežano uzimanje hrane i na neÅ”to teži izgovor pojedinih glasova. Plan liječenja donesen je na osnovi sljedećih potanko provedenih postupaka: ā€¢ raŔčlamba lica rađena je na osnovi fotogarafija napravljenih iz profila i en face ā€¢ raŔčlamba okluzije učinjena je na studijskim modelima ā€¢ rentgenkefalometrijska raŔčlamba profilnog i AP kraniograma učinjena računalom i ručno samo je potvrdila već spomenutu dijagnozu Liječenje je provedeno isključivo intraoralnom i ekstraoralnim ortodontskim napravama te smo smatrali korisnim iznijeti naÅ”a iskustva ovakvim načinom liječenja. Izgled pacijentice nakon liječenja vidi se na slikama. Ponovne kefalometrijske raŔčlambe rađene su nakon zavrÅ”etka liječenja. Svi parametri su u granicama normale, kako se vidi iz tabele s prikazanim vrijednostima prije i poslije liječenja. RaŔčlambe mekih česti pacijentice također pokazuju znatne promjene, a odnosi nos, gornja usnica, donja usnica i brada veoma su dobri. Dentofacijalni deformiteti danas se vrlo uspjeÅ”no rjeÅ”avaju. Dobre studijske raŔčlambe, na osnovi kojih se određuje plan liječenja, jamstvo su uspjeÅ”noga liječenja. Vrlo malo je ostalo tajni u liječenju dentofacijalnih deformiteta, ali ona od terapeuta traži visoku profesionalnost i učinkovitost.Disharmony of the jaws presents a great aesthetic and functional problem for patients. The reason for reporting to a clinic is mainly of an aesthetic nature, since most commonly young people are involved, while functional disturbances remain secondary. Such persons have difficulty eating, speaking and breathing. We will present one case of combined dentofacial deformity: PROGNATHISMUS ET LATEROGNATHISMUS MANDIBULARIS. Female patient, 34 years old. From anamnestic data we did not find out whether there were similar problems in the family. The motive for reporting to the clinic was aesthetics, although the patient complained of pain in both temporomandibular joints, difficulty eating and somewhat more difficult pronunciation of certain vocals. A treatment plan was based on: ā€¢ Analysis of the face, based on profile and en face photographs. ā€¢ Analysis of occlusion, based on study models. ā€¢ Roentgen-cephalometry of the profile and AP craniogram, performed on a computer as well as manually, confirmed the above mentioned diagnosis. The treatment was performed exclusively with intraoral and extraoral orthodontic appliances, and we therefore believe that it would be useful to present our experience with such a treatment method. The appearance of the patient after treatment can be seen on the photographs. Repeated cephalometric analyses were performed after completion of the treatment. All parameters were within normal limits, as can be seen from the table presenting pre- and post treatment values. Analysis of the soft tissues also shows significant changes, and relations between the nose, upper lip, lower lip and chin are very good. Today dentofacial deformities are successfully solved. Good study analyses, which serve as the base for planning treatment, guarantee successful treatment. There are very few secrets in ortognatic treatment, but it still requires high professionalism and effectivness

    Numerical research of compressible turbulent swirl flow with energy separation in a cylindrical tube

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    Cilj ovog rada je numerička analiza fenomena raslojavanja polja totalne temperature u turbulentnom stiÅ”ljivom vihornom strujanju u cilindričnoj cevi. U tom smislu, raslojavanje polja totalne temperature u vrtložnoj cevi sa potpuno zatvorenim otvorom za izlaz ohlađenog gasa se analizira numeričkim putem primenom softverom otvorenog tipa - OpenFOAM. Validacija dobijenih numeričkih rezultata je vrÅ”ena poređenjem sa vrednostima dobijenim eksperimentalnim putem. Za numeričke proračune koriste se dvojednačinski model (standardni k-Īµ) i puni naponski model turbulencije (LRR). Proračunski domen se smatra dvodimenzionalnim, a radni fluid - vazduh tretira se kao kalorički idealni gas. Uticaj broja ćelija u mreži je izvrÅ”en pomoću četiri različite veličine mreže. Raspodele jačine vihora, srednjeg vihora i ugaone brzine jasno ukazuju na uticaj prisustva vihora u strujnom polju. Sa druge strane, združeno sa njihovom vrednoŔću upućuju i na fiziku ovog izuzetno kompleksnog strujno-termodinamičkog fenomena kakav je fenomen raslojavanja polja totalne temperature. Na osnovu vrednosti i raspodela ovih strujnih veličina, izvrÅ”eno je i poređenje između stiÅ”ljivog i nestiÅ”ljivog turbulentnog vihornog strujanja.The aim of this paper is to numerically analyze the energy separation phenomenon in turbulent compressible swirling flow in a cylindrical tube. In that sense, the energy separation in a vortex tube with orifice at cold end closed completely is examined numerically using OpenFOAM software. Obtained results are validated with the experimental ones. For numerical calculations, both two-equation (standard k-Īµ) and full Reynolds stress turbulence models (LRR) are used. The computational domain is considered to be two-dimensional, and the working fluid - air is treated as calorically perfect gas. Mesh independence test is carried out for four different mesh sizes. Distributions of swirling flow intensity, average swirl and angular velocity clearly show the influence of the swirl presence in the flow. The values of these quantities point to the physics of this extremely complex flow-thermodynamic phenomenon, such is the energy separation. Based on values and distributions of these flow quantities a comparison between incompressible and compressible turbulent swirling flow is performed

    Numerical research of compressible turbulent swirl flow with energy separation in a cylindrical tube

    Get PDF
    Cilj ovog rada je numerička analiza fenomena raslojavanja polja totalne temperature u turbulentnom stiÅ”ljivom vihornom strujanju u cilindričnoj cevi. U tom smislu, raslojavanje polja totalne temperature u vrtložnoj cevi sa potpuno zatvorenim otvorom za izlaz ohlađenog gasa se analizira numeričkim putem primenom softverom otvorenog tipa - OpenFOAM. Validacija dobijenih numeričkih rezultata je vrÅ”ena poređenjem sa vrednostima dobijenim eksperimentalnim putem. Za numeričke proračune koriste se dvojednačinski model (standardni k-Īµ) i puni naponski model turbulencije (LRR). Proračunski domen se smatra dvodimenzionalnim, a radni fluid - vazduh tretira se kao kalorički idealni gas. Uticaj broja ćelija u mreži je izvrÅ”en pomoću četiri različite veličine mreže. Raspodele jačine vihora, srednjeg vihora i ugaone brzine jasno ukazuju na uticaj prisustva vihora u strujnom polju. Sa druge strane, združeno sa njihovom vrednoŔću upućuju i na fiziku ovog izuzetno kompleksnog strujno-termodinamičkog fenomena kakav je fenomen raslojavanja polja totalne temperature. Na osnovu vrednosti i raspodela ovih strujnih veličina, izvrÅ”eno je i poređenje između stiÅ”ljivog i nestiÅ”ljivog turbulentnog vihornog strujanja.The aim of this paper is to numerically analyze the energy separation phenomenon in turbulent compressible swirling flow in a cylindrical tube. In that sense, the energy separation in a vortex tube with orifice at cold end closed completely is examined numerically using OpenFOAM software. Obtained results are validated with the experimental ones. For numerical calculations, both two-equation (standard k-Īµ) and full Reynolds stress turbulence models (LRR) are used. The computational domain is considered to be two-dimensional, and the working fluid - air is treated as calorically perfect gas. Mesh independence test is carried out for four different mesh sizes. Distributions of swirling flow intensity, average swirl and angular velocity clearly show the influence of the swirl presence in the flow. The values of these quantities point to the physics of this extremely complex flow-thermodynamic phenomenon, such is the energy separation. Based on values and distributions of these flow quantities a comparison between incompressible and compressible turbulent swirling flow is performed
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