Search results for "Geometrie"

Genesi geometrica delle volte centriche

1996

Un'analisi completa degli organismi voltati comporta lo studio delle molteplici componenti necessarie alla loro definizione: configurazione geometrica, sistema costruttivo, area storico-geografica di appartenenza, interpretazioni Stilistiche. L’obiettivo di questo studio è indirizzato all' analisi delle volte continue su pianta centrica definibili attraverso le leggi della geometria euclidea. L’indagine si pone all'interno dei confini relativi alla loro configurazione geometrica e il criterio adottato, svincolato da classificazioni di carattere tipologico o stilistico, propone l'identificazione di famiglie geometriche in base alla figura del poligono di base dell'impianto. Si può identifica…

L’ A B S I D E. COSTRUZIONE E GEOMETRIE

2015

Le absidi costituiscono solitamente la prima parte di una fabbrica che viene posta in opera. L'aspettativa di tempi lunghi del cantiere spinge a realizzare immediatamente opere fastose e decorate in grado di gratificare committenti che non vedranno mai conclusi i lavori. Dal punto di vista geometrico i progetti prodotti nell'Europa del Sud hanno seguito, nei secoli, schemi per lo più convenzionali (strutture semicircolari, quadrangolari o generate da poligoni ottagonali) ma non mancano le eccezioni e i tentativi di definire soluzioni alternative (valgano per tutte la struttura treboladas castigliane, la scelta di usare l'abside come base per un campanile o le conformazioni derivanti da poli…

Analytische Geometrie nach Prof. Dr. F. Schur

1892

Observation of a superfluid component within solid helium

2011

We demonstrate by neutron scattering that a localized superfluid component exists at high pressures within solid helium in aerogel. Its existence is deduced from the observation of two sharp phonon-roton spectra which are clearly distinguishable from modes in bulk superfluid helium. These roton excitations exhibit different roton gap parameters than the roton observed in the bulk fluid at freezing pressure. One of the roton modes disappears after annealing the samples. Comparison with theoretical calculations suggests that the model that reproduces the observed data best is that of superfluid double layers within the solid and at the helium-substrate interface. peerReviewed

Seminararbeiten von Semester 71/72, 72, 72/73

1801

Angle Factors and Projected Area Factors for Comfort Analysis of Subjects in Complex Confined Enclosures: Analytical Relations and Experimental Resul…

2008

This paper addresses an important problem in the evaluation of the thermal comfort of people living or working in the sort of confined spaces typical of current architecture. In the details, a new algorithm is proposed for the evaluation of the angle factors of people within rooms characterized by complex shapes, where the envelope components are not always mutually orthogonal. The algorithm is based on field data obtained by means of an experimental photographic apparatus which allows measurements of projected area factors of seated or standing people in such complex confined environments.

Radiative heat exchanges of people in complex geometry buildings: An experimentally based algorithm for computing angle factors

2008

Thermal comfort of people working or living in confined spaces depends, to a large extent, on the radiative thermal exchanges. These contributions are expressed, among other things, as a function of the mean radiant temperature that, in the general cases where there is a presence of high intensity sources, must be expressed as a function of the angle factors between subjects and the surrounding surfaces of enclosures. Angle factors, in turn, depend on the projected area factors. Despite this evidence, at the present there is a lack in the availability of simple and reliable methods capable of computing angle factors of people in assigned postures with respect to complex geometry buildings. …

Fraktale Geometrie – Ästhetisches Spielzeug oder Weg zur Naturerkenntnis?

1994

Modeling of a continuous photocatalytic reactor for isovaleraldehyde oxidation: Effect of different operating parameters and chemical degradation pat…

2013

International audience; An investigation of isovaleraldehyde (ISOV) photocatalytic oxidation was conducted at initial concentrations ranging from 25 to 150 mg/m3 and different relative humidities (5-90% RH) in order to characterize the process performances close to indoor air conditions. Experiments were carried out in two different reactors: cylinder and flat-plate photoreactor (planar reactor) at different air gap (20-60 mm) and gas residence times (0.67-5.0 s). A plug flow reactor system was developed in order to perform kinetic studies of (i) isovaleraldehyde removal, (ii) selectivity of CO2, (iii) byproducts formation and removal. It appears that ISOV removal efficiencies increased wit…

A High-Resolution Penalization Method for large Mach number Flows in the presence of Obstacles

2009

International audience; A penalization method is applied to model the interaction of large Mach number compressible flows with obstacles. A supplementary term is added to the compressible Navier-Stokes system, seeking to simulate the effect of the Brinkman-penalization technique used in incompressible flow simulations including obstacles. We present a computational study comparing numerical results obtained with this method to theoretical results and to simulations with Fluent software. Our work indicates that this technique can be very promising in applications to complex flows.