1,721,207 research outputs found
Microstructural features of roasted coffee beans investigated by synchrotron x-ray microtomography
No full textVascular network organization in posterior atrophic human mandible: a guide for an appropriate surgical approach
No full textBackground: The bone vascularity plays a key role for a successful surgical approach during implant placement on the posterior
atrophic lower jawbone. Although, some very old references are reported on animal studies, to the author best knowledge no
data are present in literature regarding this subject.
Aim/Hypothesis: The aim of this work was to evaluate the vascular arrangement in posterior, edentulous, atrophic mandibular
crests on humans
Preliminary results in the use of synchrotron radiation for small cracks and defects investigation in AA FSW samples
No full textA very good definition of defects position and dimension in welded joints is desirable for application of
fracture mechanics techniques and improvement of industrial acceptability criteria. This paper illustrates the
preliminary results obtained in the investigation of defects in aluminum welded joints at SYRMEP beamline of the
Elettra synchrotron radiation facility in Trieste (Italy). The novel PHase Contrast (PHC) imaging technique
consents a definition of the defects better than the one achievable with conventional welded joints control methods
such as ultrasonic techniques, acoustic emission and radiography
Seismically induced slope instability maps validated at an urban scale by site numerical simulations
No full textMaps of seismically induced instability at the urban scale can be drawn by means of geographic information
system (GIS) tools that integrate different information layers such as (1) a landslide inventory; (2) a digital
elevation model (DEM); (3) geo-hydro-mechanical site characterization, and (4) measured peaks or integral
parameters at seismic stations. These maps are used to guide planning activities and emergency actions, but their main limitation is typically the lack of reliable analyses or calibrations. In this study, a possible method is proposed to control and increase the overall reliability of an hazard scenario map of earthquake-induced slope instability. The procedure can be summarized in the following steps: (1) GIS tools are used to describe the spatial distribution of the hydro-mechanical properties of the surface lithologies; (2) seismically induced instability maps of permanent displacements are drawn from the preceding information layers combined with seismic parameters spatially propagated by means of spatial interpolation tools; (3) point dynamic and stability numerical analyses are carried out by means of a commercial finite element method (FEM) code
(e.g., Geostudio2004) to calculate permanent displacement by the Newmark’s method along representative cross-sections. The numerical analyses are used to calculate a ‘‘depth factor’’, which can be considered as the contribution of the seismic local amplification to the surface calculations addressed by GIS tools. The ratio between the results drawn from the two approaches (GIS-based and FEM-based implementing Newmark’s method) can be assumed as a scale factor related to the in-depth sitespecific geo-lithotechnical characters to be addeded to GIS maps
A strategy to address the task of seismic micro-zoning in landslide-prone areas
Full text linkAs concerns landslide prevention and mitigation policies at the urban scale,
the ability of Geographical Information Systems (GIS) to combine
multi-layered information with high precision enables technicians and
researchers to devote efforts in managing multiple hazards, such as
seismically induced instability in urbanized areas. As a matter of fact,
many villages in the Italian Apennines, placed near high-energy seismic
sources, are characterized by active sliding that are seasonally remobilized
by rainfall. GIS tools can be useful whether accurate Digital Elevation
Models (DEM) are available and detailed mechanical and hydraulic
characterization of superficial deposits over significant portion of the
urban territory is undertaken. Moreover, the classic methods for estimating
the seismic-induced permanent displacements within natural slopes are drawn
from the generalization of Newmark's method. Such method can be applied to
planar sliding mechanism that can be considered still valid wherever shallow
landslides are generated by an earthquake. The failure mechanism depends on
the mechanical properties of the superficial deposits. In this paper, the
town of Castelfranci (Campania, southern Italy) has been studied. This small
town, hosting two thousand inhabitants, suffers from the seasonal
reactivation of landslides in clayey soil deposits due to rainfall.
Furthermore, the site is seismically classified by means of the peak ground
acceleration (PGA) equal to 0.246 g with respect to a 475 yr return period.
Several studies on the evolution of slopes have been undertaken at
Castelfranci and maps have been drawn at the urban scale not taking into any
account the seismic hazard. This paper shows possible seismically induced
hazard scenarios within the Castelfranci municipal territory aimed at
microzonation of level 2, by estimating the slope permanent displacements
comparable to those caused by the strongest historical seismic event that
hit this area: the 1980 Irpinia earthquake. To this aim, geotechnical
characterization of local soils collected over the last 25 yr by local
technicians have been used to predict possible permanent displacements by
means of Newmark's sliding block approach. Two simplified relationships
relating peak ground acceleration and Arias intensity to permanent
displacements have been used and compared. Although similar results are
drawn, the two analyses point out the most hazardous sectors of the
Castelfranci urban area
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
A comparative evaluation of ring artifacts reduction filters for X-ray computed microtomography images
No full textThe X-ray tomography technique for fatigue cracks reconstruction in Al 5083 specimen
No full textThe X-ray tomography technique for fatigue cracks reconstruction in Al 5083 specime
- …
