Three-dimensional dynamic response analyses of Cogswell Dam

1995 ◽  
Vol 32 (3) ◽  
pp. 452-464 ◽  
Author(s):  
Ross W. Boulanger ◽  
Jonathan D. Bray ◽  
Scott M. Merry ◽  
Lelio H. Mejia
Keyword(s):  
Dynamic Response ◽  
Dynamic Properties ◽  
Three Dimensional ◽  
Strong Motion ◽  
Topographic Effects ◽  
Embankment Dams ◽  
Rockfill Materials ◽  
Wide Range ◽  
Sierra Madre

The recorded strong motions at Cogswell Dam during the 1987 Whittier Narrows and 1991 Sierra Madre earthquakes provide a valuable opportunity to evaluate the applicability of established engineering procedures for evaluating the dynamic response of dams with highly three-dimensional geometries. In addition, these records provide an opportunity to back-calculate the dynamic properties of rockfill materials, which cannot be easily measured in the laboratory or in situ. Peak transverse crest accelerations of 0.15 g and 0.42 g were recorded during the Whittier Narrows and Sierra Madre earthquakes, respectively. Combined with analyses of the trailing portions of these strong motion records, the field data cover a wide range of induced shear strains. Two-dimensional and three-dimensional dynamic response analyses were performed using established engineering procedures, and their results are compared with the recorded responses. Dam–canyon interaction and topographic effects appear to have influenced the seismic response of the dam significantly. Estimates of the in situ dynamic rockfill properties, including the modulus degradation relationship, are presented. Key words : rockfill, dynamic properties, embankment dams, earthquake response.

Diversity of the sponge fauna associated with white coral banks from two Sardinian canyons (Mediterranean Sea)

2019 ◽  
Vol 99 (8) ◽  
pp. 1735-1751 ◽  
Author(s):  
M. Bertolino ◽  
S. Ricci ◽  
S. Canese ◽  
A. Cau ◽  
G. Bavestrello ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Cold Water ◽  
Three Dimensional ◽  
Western Mediterranean ◽  
Tyrrhenian Sea ◽  
Lophelia Pertusa ◽  
Wide Range ◽  
Santa Maria

AbstractThe three-dimensional coral scaffolds formed by the skeletons of the cold-water corals Madrepora oculata and Lophelia pertusa represent an important deep-sea hard substratum and create an optimal shelter for a rich associated fauna in which the contribution of Porifera has still not been fully considered. The taxonomic analysis of sponges collected from two Sardinian canyons (Nora and Coda Cavallo, 256–408 m) and associated with the dead coral matrix resulted in 28 species, including new records for the Mediterranean Sea, Italian fauna or Central Tyrrhenian Sea. In addition, for many species this is the first finding associated with the coral framework or the first documentation of the in situ morphology. The taxonomic comparison with sponge assemblages associated with coral frameworks from Santa Maria di Leuca, Strait of Sicily and Bari Canyon, gave the opportunity to evaluate the similarities among geographically separated banks. Overall, the percentage of exclusive species (recorded only in one site), is very high (81%) and only one species is shared by all four sites, suggesting a low connectivity among the sponge communities. The percentage of shared species is higher for the Maltese community, supporting the role of the Sicily Channel as a crossroads between the communities of the eastern and western Mediterranean basins. Here, 55% of the sponges associated to the coral framework are also reported in shallow-water coralligenous assemblages, indicating a high bathymetric connectivity as well as an ecological plasticity allowing these species to occupy a wide range of small, dark refuges.

Instrumentation de barrages par accélérographes

1995 ◽  
Vol 22 (1) ◽  
pp. 150-163
Author(s):  
Georges R. Darbre
Keyword(s):  
Key Words ◽  
Dynamic Behaviour ◽  
Dynamic Properties ◽  
Free Field ◽  
Strong Motion ◽  
Gravity Dams ◽  
Arch Dams ◽  
Embankment Dams ◽  
Technical Specifications

A better understanding of the dynamic behaviour of dams requires strong-motion instrumentations. In particular, it is necessary to observe the free-field motions at the dam sites and the effective motions along the abutments, and to determine the dynamic properties of dams and their response to severe earthquakes. Instrumentation schemes are developed for arch dams, gravity dams and embankment dams, considering specific observational needs and objectives. The technical specifications to be satisfied by the accelerographs and the arrays are developed. Four arrays, which have been installed in Swiss dams ranging in height from 120 to 285 m, for a total of 29 triaxial accelerographs, are also presented. Key words: earthquakes, strong motions, instrumentation, accelerographs, dams.

Multiscale 3D Virtual Dissections of 100-Million-Year-Old Flowers Using X-Ray Synchrotron Micro- and Nanotomography

2014 ◽  
Vol 20 (1) ◽  
pp. 305-312 ◽  
Author(s):  
Jean-David Moreau ◽  
Peter Cloetens ◽  
Bernard Gomez ◽  
Véronique Daviero-Gomez ◽  
Didier Néraudeau ◽  
...  
Keyword(s):  
Phase Contrast ◽  
Three Dimensional ◽  
Multiscale Approach ◽  
X Ray ◽  
Local Tomography ◽  
Transmission Electron ◽  
Wide Range ◽  
Fossil Flowers ◽  
High Level

AbstractA multiscale approach combining phase-contrast X-ray micro- and nanotomography is applied for imaging a Cretaceous fossil inflorescence in the resolution range from 0.75 μm to 50 nm. The wide range of scale views provides three-dimensional reconstructions from the external gross morphology of the inflorescence fragment to the finest exine sculptures of in situ pollen. This approach enables most of the characteristics usually observed under light microscopy, or with low magnification under scanning and transmission electron microscopy, to be obtained nondestructively. In contrast to previous tomography studies of fossil and extant flowers that used resolutions down to the micron range, we used voxels with a 50 nm side in local tomography scans. This high level of resolution enables systematic affinities of fossil flowers to be established without breaking or slicing specimens.

A system for the analysis and comparison of oceanographic data from satellite-borne and in-situ sensors

1988 ◽  
Vol 324 (1579) ◽  
pp. 347-363
Keyword(s):  
Satellite Images ◽  
Three Dimensional ◽  
Satellite System ◽  
Input Devices ◽  
Wide Range ◽  
In Situ Sensors ◽  
Modelling Studies ◽  
Machine Interface ◽  
Oceanographic Data

ODESSA is an Oceanographic Database and Environmental Satellite System Application developed for ARE (Portland) by Logica Space and Defence Systems Limited, under Ministry of Defence contract. It is possible to access online or historic satellite images, which may be processed and displayed in a variety of formats. The oceanographic database contains data as a function of depth that have been derived from a wide range of instruments, geographic areas and times. This database may be accessed and the data processed and displayed in a number of ways, some of which can be directly overlaid and compared with the processed satellite images. The system was designed to be flexible, with an emphasis on the man-machine interface, making extensive use of menus and graphic input devices. The flexibility allows for easy expansion to include further processing and display facilities. Examples of output displays are presented to show the application of the ODESSA system in oceanographic modelling studies and in relating sea-surface temperatures to the three-dimensional water-column structure.

scholarly journals Development of synchrotron X-ray micro-tomography under extreme conditions of pressure and temperature

2017 ◽  
Vol 24 (1) ◽  
pp. 240-247 ◽  
Author(s):  
M. Álvarez-Murga ◽  
J. P. Perrillat ◽  
Y. Le Godec ◽  
F. Bergame ◽  
J. Philippe ◽  
...  
Keyword(s):  
High Pressure ◽  
Structural Changes ◽  
Three Dimensional ◽  
Crystallographic Structure ◽  
Three Dimensional Imaging ◽  
X Ray ◽  
Wide Range ◽  
Micro Tomography ◽  
Non Destructive

X-ray tomography is a non-destructive three-dimensional imaging/microanalysis technique selective to a wide range of properties such as density, chemical composition, chemical states and crystallographic structure with extremely high sensitivity and spatial resolution. Here the development of in situ high-pressure high-temperature micro-tomography using a rotating module for the Paris–Edinburgh cell combined with synchrotron radiation is described. By rotating the sample chamber by 360°, the limited angular aperture of ordinary high-pressure cells is surmounted. Such a non-destructive high-resolution probe provides three-dimensional insight on the morphological and structural evolution of crystalline as well as amorphous phases during high pressure and temperature treatment. To demonstrate the potentials of this new experimental technique the compression behavior of a basalt glass is investigated by X-ray absorption tomography, and diffraction/scattering tomography imaging of the structural changes during the polymerization of C60 molecules under pressure is performed. Small size and weight of the loading frame and rotating module means that this apparatus is portable, and can be readily installed on most synchrotron facilities to take advantage of the diversity of three-dimensional imaging techniques available at beamlines. This experimental breakthrough should open new ways for in situ imaging of materials under extreme pressure–temperature–stress conditions, impacting diverse areas in physics, chemistry, geology or materials sciences.

scholarly journals Assessment of human-induced vibrations of a cable-stayed footbridge

2018 ◽  
Vol 211 ◽  
pp. 09001 ◽  
Author(s):  
Izabela Drygała ◽  
Joanna M. Dulinska ◽  
Marek Wazowski
Keyword(s):  
Natural Frequencies ◽  
Dynamic Properties ◽  
Three Dimensional ◽  
Fe Model ◽  
In Situ Tests ◽  
Modal Assurance Criterion ◽  
Comfort Criteria ◽  
Abaqus Software

The primary purpose of this research is the evaluation of human-induced vibrations of a cable-stayed footbridge. The cable-stayed pedestrian bridge with total length of the span equal to 46.90 m located in Czestochowa (Southern Poland) was chosen as a case study. The footbridge consists of two spans (21.10 m and 25.80 m). A three-dimensional (3D) finite element (FE) model of the footbridge was prepared with the ABAQUS software program. The dynamic properties of the structure, i.e. its natural frequencies, modes shapes and damping ratios, were estimated on the basis of the in situ tests results as well as numerical analysis. For the validation of the modal models the modal assurance criterion (MAC) theory was applied. In the next stage of the investigation the dynamic response of the structure to human-induced loading was evaluated. Finally, the vibration comfort criteria for the footbridge were checked.

scholarly journals Development of an arthroscopically compatible polymer additive layer manufacture technique

2017 ◽  
Vol 231 (6) ◽  
pp. 586-594
Author(s):  
Simon W Partridge ◽  
Matthew J Benning ◽  
Matthew J German ◽  
Kenneth W Dalgarno
Keyword(s):  
Three Dimensional ◽  
Proof Of Concept ◽  
Polymer Additive ◽  
Three Dimensional Printing ◽  
Functionally Gradient ◽  
Wide Range ◽  
Layer Manufacture ◽  
Dimensional Printing

This article describes a proof of concept study designed to evaluate the potential of an in vivo three-dimensional printing route to support minimally invasive repair of the musculoskeletal system. The study uses a photocurable material to additively manufacture in situ a model implant and demonstrates that this can be achieved effectively within a clinically relevant timescale. The approach has the potential to be applied with a wide range of light-curable materials and with development could be applied to create functionally gradient structures in vivo.

scholarly journals 3-D views of the expanding CME: from the Sun to 1AU

2012 ◽  
Vol 10 (H16) ◽  
pp. 106-108
Author(s):  
Alexis P. Rouillard
Keyword(s):  
Extreme Ultraviolet ◽  
Three Dimensional ◽  
Flux Rope ◽  
In Situ Measurements ◽  
Magnetic Flux Rope ◽  
Wide Range ◽  
Remote Sensing Techniques ◽  
Vantage Points ◽  
White Light Imaging

AbstractThree-dimensional information on Coronal Mass Ejections (CMEs) can be obtained from a wide range of in-situ measurements and remote-sensing techniques. Extreme ultraviolet (EUV) and white-light imaging sensed from several vantage points can be used to infer the 3-D geometry of the different parts that constitute a CME. High-resolution and high-cadence coronal imaging provides detailed information on the formation and release phase of a magnetic flux rope, the lateral expansion of the CME and the reconfiguration of the corona associated with the effects of pressure variations and reconnection. The evolution of the CME in the interplanetary medium and the connection of its various substructures with in-situ measurements can be obtained from multi-point heliospheric imaging.

scholarly journals Linear dynamic properties in curved laminated glasses

2021 ◽  
pp. 44-47
Author(s):  
Olga Sukhanova ◽  
Олексій Ларін
Keyword(s):  
Finite Element ◽  
Degrees Of Freedom ◽  
Dynamic Properties ◽  
Three Dimensional ◽  
Mesh Size ◽  
Polyvinyl Butyral ◽  
Laminated Glass ◽  
Wide Range ◽  
Curvature Parameter ◽  
Work Model

The study presents the results of linear dynamics of laminated glass panels with different curvatures. This is an actual task in the field of mechanical engineering, aviation, shipbuilding, energy, architecture, etc. Such composites are durable, easy to care for and have a wide range of design options. The aim of the work is to study the influence of the curvature parameter on the frequencies and modes of composites. The paper considers the linear characteristics for laminated glass with polyvinyl butyral interlayer. The article considers behavior of the triplex and the propagation of elastic waves in the linear state. The paper performs calculations using the finite element method in the framework of modal analysis in a three-dimensional formulation in the framework of a physical linear-elastic formulation. The study uses hexagonal finite element with 8 nodes with 3 degrees of freedom in each. This work model laminated glass with a curvature parameter ranging from 0 mm to 250 mm. The composite consisted of three layers: two glass layers thickness of each was 3 mm, and a polyvinyl butyral interlayer with 0.38 mm thickness. The size of the plates was 500×500 mm. As a boundary condition, the laminate was fixed on two opposite sides. The article performs mesh size convergence analysis. The results of natural frequencies in accordance with the curvature parameter are derived. The graphs of natural vibration modes are also shown, that give a clear view about the state of composites.

Correlated Studies of Cellular Interactions Using TEM, Freeze Etching, and SEM

1974 ◽  
Vol 32 ◽  
pp. 320-321
Author(s):  
J. P. Revel
Keyword(s):  
Developmental Stages ◽  
Three Dimensional ◽  
Cell Movement ◽  
Cellular Interactions ◽  
Serial Sections ◽  
Cell Sheets ◽  
Freeze Etching ◽  
Early Developmental

Movement of individual cells or of cell sheets and complex patterns of folding play a prominent role in the early developmental stages of the embryo. Our understanding of these processes is based on three- dimensional reconstructions laboriously prepared from serial sections, and from autoradiographic and other studies. Many concepts have also evolved from extrapolation of investigations of cell movement carried out in vitro. The scanning electron microscope now allows us to examine some of these events in situ. It is possible to prepare dissections of embryos and even of tissues of adult animals which reveal existing relationships between various structures more readily than used to be possible vithout an SEM.

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