1,721,161 research outputs found
Elaborazione dell’indice SMR mediante overlay di carte tematiche: un caso applicativo nella Valle del Serchio (Toscana nord-occidentale)
No full textThis study was carried out after the realization of numerous geomechanical analyses, finalized to the stability analysis of rock walls during a carriageway widening in a mountainous area. With this aim, a cartography based on SMR Index of Romana was realized, through a spatial analysis of both geomechanical parameters and the distribution of the discontinuities. This approach therefore allowed the estimation of the potentially unstable zones for each area and their classification on the basis of the resulting stability degree. Such methodological approach could find an important application above all in scarcely accessible zones, where, however, a good structural homogeneity exists. This methodology was elaborated during geomechanical surveys, aimed at the realization of structural engineering works in the Middle Valley of the Serchio River. The purpose of the study consisted in the determination of the corrected profile of the slope based on the stability conditions of the rock masses and the consequent planning of eventual works as support. The data elaboration allowed the individuation of the most critical areas, prone to sliding or toppling. This study revealed particularly suitable to experimentation, because it regarded a meaningful area with spatially homogenous geological/geomechanical/structural situation. The data obtained, appropriately compared with traditional methods, showed a good degree of reliability
Geomechanical features and landslide susceptibility of rock formations in Northern Tuscany (Italy)
No full textSeveral different geological formations crop out in the Northern Tuscany (Italy), where the geological, morpho-climatic and seismic characteristics determine high landslide susceptibility. This study particularly focuses on the upper Serchio River basin, where slope instability severely threatens population, villages and facilities. Geo-engineering survey and characterization with in situ and laboratory tests were performed, in order to define rock mass classification and geotechnical properties of the most widespread rocky formations cropping out in the basin, and assess their relationships with slope instability.
Therefore, several properties were investigated, mainly referring to rock strength, structure, spacing and conditions of discontinuities, alteration. Field and laboratory tests were performed and included Schmidt Hammer Test, Point Load Strength Test and Unconfined Compressive Strength, aiming at defining the main rock and rock mass parameters. Then, the Bieniawski’s RMR (Rock Mass Rating) and the Hoek’s GSI (Geological Strength Index) were applied, in order to obtain an overall rock mass parameterization.
Thus many dozens of geotechnical units were established and grouped according to their behaviour. Figure 1 in the next page depicts the areal distribution of the 13 main geotechnical units. Table 1 lists these units together with some related lithostratigraphic unit, and summarizes their geotechnical properties.
Subsequently, the study area was classified and subdivided into several classes, mainly based on their physical-mechanical properties. This allowed to realize a GIS-based geotechnical map of the considered area, representing the areal distribution of the geotechnical properties of the classified rock formations. Finally, this map was compared with the landslide distribution of the area, in order to assess the landslide susceptibility of the considered formations
An intramural hematoma of the ascending aorta. The radiological trap [Ematoma intramurale dell'aorta ascendente. Insidia radiologica.]
No full text[No abstract available
[The computed tomographic and magnetic resonance aspects of melorheostosis. A report of 2 cases]
No full textPulmonary function, smoking habits, and high resolution computed tomography (HRCT) early abnormalities of lung and pleural fibrosis in shipyard workers exposed to asbestos.
No full textTo evaluate the presence of asbestos-related pleural and parenchymal abnormalities and their correlation with pulmonary function and smoking habits, 119 asbestos-exposed asymptomatic workers (mean age, 46.2 years; mean duration of asbestos exposure, 8.6 years; mean latency time, 21.6 years) with normal standard P.A chest radiographs were submitted to HRCT, CO-diffusing capacity and pulmonary function tests. HRCT scans were normal only in 31 (26%) examined workers; 31 (26%) subjects showed both pleural and parenchymal involvement, and 50 (42%) and seven (6%) had exclusively pleural and parenchymal abnormalities, respectively. Based on CO-diffusing capacity and pulmonary function tests, no significant difference was demonstrated between workers with pleural lesions and subjects with normal pleura; however, lower values of FVC were observed in the nonsmoking workers with parenchymal abnormalities in comparison with nonsmoking subjects with normal parenchyma (78.2 vs. 89.7% of predicted values; p = 0.03 by student's two-tailed t test), and lower values of FEV1/FVC in the smokers with parenchymal lesions with respect to smokers with normal parenchyma (93.7 vs. 100.2% of predicted values; p = 0.005 by students' two-tailed t test). In conclusion, our results demonstrate that HRCT may detect early parenchymal abnormalities which correlate with exposure to asbestos and respiratory function impairment, including a reduction in obstructive indices in smokers occupationally exposed to asbestos, without any clinically evident disease
Direct and indirect signs of chronic pulmonary hypertension shown by computer tomography
No full textAm. Rev. Resp. Dis
La TAC come mezzo di indagine del circolo polmonare in pazienti normali e con ipertensione post-embolica
No full textLa Radiologia Medic
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