Search results for "Wedge"

Os-isotope constraints on the dynamics of orogenic mantle: The case of the Central Balkans

2015

Abstract We used Os isotopic systematics to assess the geochemical relationship between the lithospheric mantle beneath the Balkans (Mediterranean), ophiolitic peridotites and lavas derived from the lithospheric mantle. In our holistic approach we studied samples of Tertiary post-collisional ultrapotassic lavas sourced within the lithospheric mantle, placer Pt alloys from Vardar ophiolites, peridotites from nearby Othris ophiolites, as well as four mantle xenoliths representative for the composition of the local mantle lithosphere. Our ultimate aim was to monitor lithospheric mantle evolution under the Balkan part of the Alpine-Himalayan belt. The observations made on Os isotope and highly …

Evidence for boron incorporation into the serpentine crystal structure

2011

Serpentinite mud volcanoes from the Mariana forearc comprise B-rich mantle wedge peridotites serpentinized by slab fluids. The major component of these rocks are serpentine group minerals [Mg 3 Si 2 O 5 (OH) 4 ], showing highly variable textural and geochemical features. Micro-Raman spectroscopy reveals that the serpentine minerals are well-crystallized lizardite and chrysotile. In situ SIMS spot analyses and element mapping via ToF-SIMS show that B is evenly distributed across serpentine grains, suggesting that serpentine, both lizardite and chrysotile in different textural regions, can host significant amounts of B (up to ~200 μg/g) into its crystal structure. As such structurally bound B…

New Challenges of Economic and Business Development – 2012 : Conference Proceedings (May 10 - 12, 2012, Riga, University of Latvia)

2012

Support for Conference Proceedings by ERAF Project "Support for the international cooperation projects and other international cooperation activities in research and technology at the University of Latvia" No. 2010/0202/2DP/2.1.1.2.0/10/APIA/VIAA/013

Ultrasonic phased array inspection of wire plus arc additive manufacture samples using conventional and total focusing method imaging approaches

2019

In this study, three aluminium samples produced by wire + arc additive manufacture (WAAM) are inspected using ultrasonic phased array technology. Artificial defects are machined using a centre drill, ø 3 mm, and electrical discharge machining (EDM), ø 0.5-1 mm, in a cylindrical through-hole topology. The samples are first inspected using a single-element wheel probe mounted on a KUKA robot in order to investigate the feasibility of using a conventional ultrasonic transducer approach. Unfortunately, the wheel probe is found to be unsuitable for scanning the WAAM specimens and ultrasonic phased arrays are employed next. The set-up includes 5 MHz and 10 MHz arrays (128 elements) in direct cont…

2006

The objective was to study the effects of a lung recruitment procedure by stepwise increases of mean airway pressure upon organ blood flow and hemodynamics during high-frequency oscillatory ventilation (HFOV) versus pressure-controlled ventilation (PCV) in experimental lung injury. Lung damage was induced by repeated lung lavages in seven anesthetized pigs (23–26 kg). In randomized order, HFOV and PCV were performed with a fixed sequence of mean airway pressure increases (20, 25, and 30 mbar every 30 minutes). The transpulmonary pressure, systemic hemodynamics, intracranial pressure, cerebral perfusion pressure, organ blood flow (fluorescent microspheres), arterial and mixed venous blood ga…

A comparative study on the phase behaviour of highly charged colloidal spheres in a confining wedge geometry

2005

We studied the structures formed in aqueous dispersions of charged colloidal spheres under a constant low salt concentration of c = 6 × 10−6 mol l−1. Particles of diameter 2a = 1000 nm were confined to a low angle wedge geometry with plate separation 0<S<50 µm and observed with video microscopy. Irrespective of the initial particle density n we reproducibly observe the particles to migrate to the narrow wedge side on the timescale of a few days. Thereby an interface between a crystalline structure and a near particle free region is formed, which propagates slowly until the dilute region is exhausted of particles. While the origin of this separation is still unclear, the final extension of t…

Degassing vs. eruptive styles at Mt. Etna volcano (Sicily, Italy). Part I: Volatile stocking, gas fluxing, and the shift from low-energy to highly ex…

2018

International audience; Basaltic magmas can transport and release large amounts of volatiles into the atmosphere, especially in subduction zones, where slab-derived fluids enrich the mantle wedge. Depending on magma volatile content, basaltic volcanoes thus display a wide spectrum of eruptive styles, from common Strombolian-type activity to Plinian events. Mt. Etna, in Sicily, is a typical basaltic volcano where the volatile control on such a variable activity can be investigated. Based on a melt inclusion study in products from Strombolian or lava-fountain activity to Plinian eruptions, here we show that for the same initial volatile content, different eruptive styles reflect variable dega…

Eigenvectors of k–ψ-contractive wedge operators

2008

Abstract We present new boundary conditions under which the fixed point index of a strict- ψ -contractive wedge operator is zero. Then we investigate eigenvalues and corresponding eigenvectors of k – ψ -contractive wedge operators.

Biomechanical Study of the Osteoporotic Spine Fracture: Optical Approach

2021

Background and objectives: Osteoporotic spine fractures represent a significant factor for decreasing quality of life in the elderly female population. Understanding the mechanisms involved in producing these fractures can improve their prevention and treatment. This study presents a biomechanical method to produce a vertebral fracture, conducted on a human spine segment, observing the displacements and strains in the intervertebral disc, endplate, and vertebral body. Materials and Methods: We performed two tests, one corresponding to an extension loading, and the second to an axial loading. Results: The maximum displacement in the target vertebral body presented higher values in the case o…

Structural framework and crustal characteristics of the Sardinia Channel Alpine transect in the central Mediterranean

2000

Abstract The submerged area located between the Sardinia Channel and the western Sicily offshore has been investigated based on deep crustal and conventional seismic lines with the aim of illustrating the relationships between the crust and its overlying crystalline and sedimentary thrust wedge. Analyses of seismic attributes and reflector pattern, supported by dredge hauls, also provided data in areas where stratigraphic and lithologic control is absent. Crustal geometries, tectonic processes and timing of the deformation are discussed here. North of the Elimi chain (central Sardinia Channel) the reflecting body consists of superposed tectonic wedges of crystalline rocks and their Meso-Cen…