279 research outputs found
Particles, string and interface in the three-dimensional Ising model
No full textWe consider the three-dimensional Ising model slightly below its critical temperature, with boundary conditions leading to the presence of an interface. We show how the interfacial properties can be deduced starting from the particle modes of the underlying field theory. The product of the surface tension and the correlation length yields the particle density along the string whose propagation spans the interface. We also determine the order parameter and energy density profiles across the interface, and show that they are in complete agreement with Monte Carlo simulations that we perform
Structure of interfaces at phase coexistence : Theory and numerics
No full textWe compare results of the exact field theory of phase separation in two dimensions with Monte Carlo simulations for the q-state Potts model with boundary conditions producing an interfacial region separating two pure phases. We confirm in particular the theoretical predictions that below critical temperature the surplus of non-boundary colors appears in drops along a single interface, while for q > 4 at critical temperature there is formation of two interfaces enclosing a macroscopic disordered layer. These qualitatively different structures of the interfacial region can be discriminated through a measurement at a single point for different system sizes
Vortex Mass in the Three-Dimensional O(2) Scalar Theory
No full textWe study the spontaneously broken phase of the XY model in three dimensions, with boundary conditions enforcing the presence of a vortex line. Comparing Monte Carlo and field-theoretic determinations of the magnetization and energy density profiles, we numerically determine the mass of the vortex particle in the underlying O(2)-invariant quantum field theory. The result shows, in particular, that the obstruction posed by Derrick's theorem to the existence of stable topological particles in scalar theories in more than two dimensions does not in general persist beyond the classical level
Problemas de contato unilateral em placas semi-espessas, sujeitas a grandes deflexões, utilizando uma teoria de ordem superior
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro TecnologicoNeste trabalho é apresentada uma formulação incremental de elementos finitos para problemas de contato em placas, submetidas a grandes deslocamentos e com restrições unilaterais. Na formulação do problema de contato unilateral, desconsidera-se o efeito do atrito, permitindo a obtenção de uma desigualdade variacional. Para resolver numericamente esta desigualdade variacional utiliza-se o método da penalidade, no qual as condições de contato unilateral são aproximadas utilizando um fator de penalidade. Utilizando esta formulação é desenvolvido um elemento finito isoparamétrico Lagrangiano de nove nós, baseado na teoria de ordem superior de Lo, Christensen e Wu para placas. O elemento finito de placa obtido foi utilizado para resolver alguns problemas estruturais lineares e não-lineares, tais como flexão de vigas, placas retangulares e circulares submetidas a pequenos e grandes deslocamentos. Inicialmente sem restrições unilaterais, e posteriormente sujeitas a restrições unilaterais, tais como fundações rígidas. Os resultados numéricos obtidos são comparados com os resultados e soluções disponíveis na literatura
Nappe Tectonics in the Southeastern Part of the Rheinisches Schiefergebirge
No full textNappe tectonic concepts for the southeastern Rheinisches Schiefergebirge, already proposed by Kossmat (1927), are revived on the basis of new stratigraphic and tectonic findings.
The Gießen Greywacke, a turbidite sequence in the northeastern Lahn Syncline, rests unconformably on Lower through Upper Devonian rocks. Conodonts retrieved from carbonate-cemented greywackes, together with data from the literature, suggest that most (if not all) of the greywacke is Frasnian in age. As the rock units surrounding and underlying the Gießen Greywacke comprise Frasnian sediments in various carbonate and shale facies without intercalation of coarse clastic rocks, the greywackes must be interpreted as a nappe.
The greywacke unit is composed of recumbent, locally overturned folds. Its base is marked by a well-developed shear-zone with mylonites.
A number of exotic rock units, now found at the margins of the greywacke area, are interpreted as allochthonous rafts at the base of the nappe. These are: phyllonitic sediments (much stronger metamorphosed than the surrounding units, with older K/Ar ages of mica), strongly sheared tectonic lenses of spilite (with the trace-element configuration of ocean-ridge basalt), and (near Gießen) slabs of Ordovician, Silurian, Lower Devonian and Lower Carboniferous sedimentary rocks, which do not occur in the surrounding, clearly autochthonous areas.
The Gießen Nappe is probably rooted in the important shear zone which seperates the Mid German Crystalline Rise from the Northern Phyllite Zone.
The “Werra-Grauwackengebirge”, an isolated outcrop of Frasnian/Famennian greywacke, associated with a unit of phyllitic slates, lies to the northeast of the Gießen Greywacke and most likely represents a part of the Gießen Nappe. These greywackes can be regarded as equivalents of the Devonian Südharz- and Selke Greywackes, along the strike in the Southern Harz Mountains, which already since some time have been recognized as nappes.
A nappe concept is also proposed for the Kehna Greywacke and the Hörre/Kellerwald Zone of the Rheinisches Schiefergebirge, its equivalents in the Acker, Tanne and Sieber areas of the Harz Mountains, and the Flechtingen complex to the east of the Harz. All these units are chiefly composed of Upper Devonian through Lower Carboniferous clastic sediments which are seperated from their source area (the Mid German Crystalline Rise) by a belt of time-equivalent limestone/shale facies rocks. This arrangement is best explained by a nappe-tectonic emplacement of the clastic units.
The Hörre/Acker greywackes, together with the Gießen/Werra/Südharz/Selke greywackes, probably represent the infill of a Devonian flysch trough, which was originally situated at the northern margin of the Mid-German Crystalline Rise and was later overthrust on the more external parts of the Rhenohercynian Zone
Selke, John G. (Death, 1879-12-08)
No full textAddress: 27 Franklin St.Age at death: 88 yrsPg 118/1879/87/M W S/Germany/Dr. Richard/Hackman/St.John'sOriginal record filed in drawer labeled 'SEKEL-SHAVLIN'
Fotoglasplatte_Geografie_33.1712_Falkenstein im Harz
No full textGeokart_Nr: 33.1712, Beschreibung: Luftaufnahme von der Burg Falkenstein und der Selke im Selketal, Ort: Deutschland, Harz / Sachsen Anhalt, Medium, Format: Diapositiv s/w, 98x84Medium, Format: Diapositiv s/w, 98x84Erscheinungsdatum auf 19xx geschätzt. Die Fotoglasplatte stammt aus einer Zeit von 1880 bis 1940
Critical Binder cumulant of two-dimensional Ising models
No full textThe fourth-order cumulant of the magnetization, the Binder cumulant,
is determined at the phase transition of
Ising models on square and triangular lattices, using Monte
Carlo techniques. Its value at
criticality depends sensitively on
boundary conditions, details of the
clusters used in calculating the cumulant, and symmetry of the
interactions or, here, lattice structure. Possibilities to
identify generic critical cumulants are discussed
George W. Friedrich Park
No full textIn November 1934, St. Cloud State Teachers College (now St. Cloud State University) President George A. Selke announced the purchase of 51 acres of abandoned granite quarry land in southeast St. Cloud. Added to property the college already owned, the site became what is now known as George W. Friedrich Park. Though officially closed in 1976, the park has been used throughout its existence as was originally intended, as an outdoor education, recreation and conservation area. Located about one mile from campus on the east end of University Drive (then Michigan Avenue) the site has remained intact despite repeated threats to this quiet wilderness from road expansion and development. The City of St. Cloud is currently in the process of reopening the park, having completed a land exchange for a portion of the property and stating its desire to acquire the remainder of the approximately 114 acre site. As it assumes stewardship, the city is acknowledging the value of preserving and sharing a significant cultural resource. A place of quiet grandeur and natural beauty, George W. Friedrich Park holds the distinction of being the birthplace of Minnesota’s granite industry and an early conservation masterpiece
The Standing Rock Sioux, 1874-1890
No full textIt is the purpose of this thesis to prepare the way for further study and consideration of the Indian problem as presented on Standing Rock Indian Reservation. The material is largely from original sources gathered through years of work among the Indians and whites who remember the period 1874 - 1890. This paper was limited to those years because they mark an epoch in the relations of these people with our own. It begins with the drifting of the discontented Indians of the newly created reservation to and from the camp of Sitting Bull and it ends with the death of this great patriot and leader of the Hunkpapa Sioux.
Documentation is therefore confined almost entirely to reports of the United States Commissioner of Indian Affairs from 1874 to 1891, to copies of the original letters of United States Indian agents at Standing Rock during this period, and to works of such men as Major ‘McLaughlin and Stanley Vestal who drew their material from the same sources that I found to be the most authentic available, the people with whom I-have lived and associated with so intimately.
It is to such notables as Chief White Bull, Chief One Bull, Dog Eagle, Kills Pretty Enemy, Male Bear, Little Moon, Jim All Yellow, Has Holy, Two Bulls, and Swift Hawk among the older Indians, Robert Higheagle, Cecelia One Bull Brown, Pius Bigshield, Mrs. Frances Long Chase, and Abraham Buckley of the second generation, Frank Whitebuffaloman, Francis Zahn, Wallace Eagle Shield, and Jesse Taken Alive of the younger generation of Indians that I owe much of my material on the Indians of the older days.
To Ott Black, Charlie Armstrong, Jacob Horner, Col. Mathew F. Steele, Frank B. Fiske, and William Mcflider I am indebted for their stories of life among the Indians during the period with which we are concerned. My first-hand sources, verbal and written, contain both the Indian and the white viewpoint. The material will be presented as given without any attempt to distort or color to obtain the viewpoint of the author
- …
