Search results for "Spiral"
showing 8 items of 138 documents
Drei-Phasen-Spiral-CT in der Diagnostik von Lebererkrankungen: Vergleich mit CT-Arteriographie und -Arterioportographie
1996
PURPOSE Assessment of the diagnostic efficacy of triphasic spiral-CT scanning (TPS-CT) for liver disease evaluation. CT arteriography (CTA) and CT arterio-portography (CTAP) were used as reference, methods which together have the highest sensitivity for detecting tumours and the perfusion conditions of the liver. MATERIAL AND METHODS 50 TPS-CT and CTA/CTPA were performed in 49 patients. After an initial examination without enhancement the first scan was initiated 15-25s after the peripheral bolus injection of contrast medium, the second after an interscan delay of 20-25s. By this means the liver was imaged in different phases of perfusion. In the course of the CTA/CTPA-exam the imaging was …
I testi dell'analogia: introduzione alla prima edizione americana de L'architettura della città
2012
La tradizione dell’architetto-scrittore ha molti precedenti nella storia dell’architettura italiana. Dal Rinascimento all’Ottocento era caratteristica di certi architetti il presentare le loro idee in forma di trattati sistematici. Sul modello di Vitruvio, Alberti produsse il modello rinascimentale per tale tipo di scrittura. Fu seguito dalla trattatistica di Serlio e Palladio. Serlio compose una serie di volumi che costituirono veri e propri manuali per l’architettura, iniziando dall’edificio antico sino ad arrivare a riflessioni su lavori futuri non ancora realizzati. La rilevanza di tali progetti non costruiti, destinati a diventare più importanti dei modesti progetti effettivamente real…
GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
2017
On August 17, 2017 at 12-41:04 UTC the Advanced LIGO and Advanced Virgo gravitational-wave detectors made their first observation of a binary neutron star inspiral. The signal, GW170817, was detected with a combined signal-to-noise ratio of 32.4 and a false-alarm-rate estimate of less than one per 8.0×104 years. We infer the component masses of the binary to be between 0.86 and 2.26 M, in agreement with masses of known neutron stars. Restricting the component spins to the range inferred in binary neutron stars, we find the component masses to be in the range 1.17-1.60 M, with the total mass of the system 2.74-0.01+0.04M. The source was localized within a sky region of 28 deg2 (90% probabili…
Il simbolismo della spirale nella panificazione cerimoniale
2008
Il saggio analizza, attraverso un'ampia ricerca transculturale, la ricorrenza del simbolismo della spirale in rapporto ai temi della maternità e della commemorazione dei defunti al fine di evidenziare eventuali comuni contenuti semantici, e non rapporti meramente formali, tra i diversi contesti in cui appaiono simboli spiraliformi.
LA SCALA DI MOMO AI MUSEI VATICANI. Curve coniche gobbe e superfici rigate da esse generate.
2014
This study is part of a more vast research that aims to examine in depth the geometrical-spatial origin of skew curves belonging to conical surfaces of revolution: conical spiral and conical helix. The study begins with an investigation concerning the geometrical tracing, and the spatial origin of both the skew curves and the ruled surfaces they generate, carrying out a comparison of the different formal characteristics through a number of algorithms that control the reference properties, written within the renown Rhinoceros plug-in, Grasshopper. Then follows an in-depth analysis of an admirable example of architecture dating back to the first thirty years of the past century and made by th…
Broncoscopia virtuale in pazienti con lesioni endobronchiali stenosanti. Ottimizzazione della tecnica con TC spirale monostrato
2004
PURPOSE: To describe an original protocol for single slice spiral Computed Tomography (CT) virtual bronchoscopy in the evaluation of patients with central airway stenoses and compare the results with fibreoptic bronchoscopy. MATERIALS AND METHODS: Ten patients (4 female and 6 male; age range 22-60 years; mean age 44 years) with endobronchial disease diagnosed by fibreoptic bronchoscopy (8 malignant tumours, 1 benign tumour and 1 fibroid stenosis) underwent virtual bronchoscopy with single slice spiral CT. A panoramic spiral CT scan of the whole chest was first obtained. Once the area of interest had been identified, a new contrast enhanced scan was performed, from bottom to top, with the fo…
Study and Simulation of Helicopter Gearboxes Noise
2010
International audience; Main gearbox is one of the main noise sources in helicopter cabin. In order to improve the comfort of customers and reduce the health impact, acoustic and vibration mechanisms of gearboxes have to be understood and simulated during development phases. Thus, we first present the global methodology chosen to compute main gearboxes noise in helicopter cabins. Secondly, we described the way we compute mechanical excitation sources induced from gear mesh, static transmission error and meshing stiffness. Depending on the type of gear, we compute those using either analytical specially developed code or EC codes. Thirdly, we propose a modeling to compute dynamic loads on be…