Search results for "Ridge"
showing 10 items of 531 documents
NaI/CuI–II heterometallic cages interconnected by unusual linear 2-coordinate OCN-Cu(I)-NCO links: synthesis, structural, magnetostructural correlati…
2009
A new Na(I)/Cu(I-II) heterometallic coordination complex [Cu(2)L(2)Na(NCO)(2)Cu](n) (1) with an unusual architecture has been synthesised. In 1 cyclic Na-O-Cu-O-Cu cages constructed by the tetradentate N(2)O(2) donor Schiff base ligand (H(2)L = N, N'-bis(2-hydroxyacetophenone) propylenediimine) are interconnected to each other by a rare singly end-to-end bridged OCN-Cu(I)-NCO link generating 1D chain. The complex has been characterised by elemental, spectral and structural analysis. The cyclic voltammogram of 1 has been compared with the analogous complexes. Cryomagnetic susceptibility studies indicate the copper(II) centers in the cyclic Na-O-Cu-O-Cu cages are antiferromagnetically coupled…
BROWNIAN DYNAMICS SIMULATIONS WITHOUT GAUSSIAN RANDOM NUMBERS
1991
We point out that in a Brownian dynamics simulation it is justified to use arbitrary distribution functions of random numbers if the moments exhibit the correct limiting behavior prescribed by the Fokker-Planck equation. Our argument is supported by a simple analytical consideration and some numerical examples: We simulate the Wiener process, the Ornstein-Uhlenbeck process and the diffusion in a Φ4 potential, using both Gaussian and uniform random numbers. In these examples, the rate of convergence of the mean first exit time is found to be nearly identical for both types of random numbers.
The (micro) processes of integration as dialectic of structure and agency : the case of seconded national experts within the European Commission
2008
Masteroppgave i offentlig politikk og ledelse - Universitetet i Agder 2008 Micro-processes of integration – i.e. how agents develop identities, properties and decision-making behaviours preferred by a particular institution – have been a topic of significant scholarly debate. Most previous work builds on one underlying theoretical framework and thereby excludes (potentially important) elements lying outside it. My thesis attempts to contribute to the ongoing debate by developing a more holistic understanding of these processes, based on the dialectics of structure and agency and thereby positions actors’ decision-making behaviour on a continuum between ‘structural idiocy’ and ‘structural en…
Stress generation at ridge axes by plate divergence and magma rise
1995
Abstract A model is explored for the rifting process particularly at the divergent plate boundary in Iceland, based on direct observations of the Krafla rifting episode 1975–1984. Magma accumulates near the axial crust-mantle transition as the plates diverge from each other and compression on the boundary decreases. Two-dimensional finite-element modelling is applied to investigate how divergence and buoyant rise of magma interact in triggering rifting. Both processes are found to be important, but long intervals between rifting episodes require the time-average deviatoric stress to be compressible normal to the axis.
Ridge-enhanced optical transmission through a continuous metal film
2004
Optical transmission through a continuous (without holes) metal film with a periodic structure of metal or dielectric ridges on one or both interfaces was numerically studied. The dependencies of the transmission on the ridge width and height as well as the ridge arrangements on the opposite interfaces were investigated in weak- and strong-coupling regimes. The transmission enhancement was shown to depend on the relative position of the ridge gratings on the opposite interfaces of a film, confirming the role of resonant tunneling processes involving states of the surface polariton Bloch modes.
Intervention strategies for the enhancement of the Peruvian route of the Inca royal path Qhapaq Ñan
2023
Qhapaq Ñan, a UNESCO World Heritage Site, was a complex administrative communication and transport system that connected the immense territory of the Inca empire for over 30 thousand km, intercepting sites of great historical and cultural interest today, first of all the Sanctuary of Machu Picchu. The consequences of climate change and the high tourist presence, which is mostly concentrated in Machu Picchu, are seriously jeopardizing the survival of this precious asset. The heavy rains that hit the monuments produce dangerous infiltrations of water between the masonry structures, compromising their stability; the transit of people along the paths and stairways erodes the rock and the soil. …
Focal adhesions are hotspots for keratin filament precursor formation
2006
Recent studies showed that keratin filament (KF) formation originates primarily from sites close to the actin-rich cell cortex. To further characterize these sites, we performed multicolor fluorescence imaging of living cells and found drastically increased KF assembly in regions of elevated actin turnover, i.e., in lamellipodia. Abundant KF precursors (KFPs) appeared within these areas at the distal tips of actin stress fibers, moving alongside the stress fibers until their integration into the peripheral KF network. The earliest KFPs were detected next to actin-anchoring focal adhesions (FAs) and were only seen after the establishment of FAs in emerging lamellipodia. Tight spatiotemporal …
Autogenous teeth used for bone grafting: A systematic review
2018
Background Recently, bone graft materials using permanent teeth have come to light, and clinical and histological outcomes of this material have been confirmed by some studies. The aim of this systematic review was to evaluate the reliability of the autogenous tooth bone graft material applied to alveolar ridge augmentation procedures. Material and Methods A systematic review of literature was conducted analyzing articles published between 2007 and 2017. The following four outcome variables were defined: a) implant stability b) post-operative complication c) evaluation of implant survival and failure rates, and d) histological analysis. A total of 108 articles were identified; 6 were select…
Análisis de métodos de validación cruzada para la obtención robusta de parámetros biofísicos
2015
[EN] Non-parametric regression methods are powerful statistical methods to retrieve biophysical parameters from remote sensing measurements. However, their performance can be affected by what has been presented during the training phase. To ensure robust retrievals, various cross-validation sub-sampling methods are often used, which allow to evaluate the model with subsets of the field dataset. Here, two types of cross-validation techniques were analyzed in the development of non-parametric regression models: hold-out and k-fold. Selected non-parametric linear regression methods were least squares Linear Regression (LR) and Partial Least Squares Regression (PLSR), and nonlinear methods were…
Stressing Sequence for Hanger Replacement of Tied-Arch Bridges with Rigid Bars
2022
The construction of bridges with suspenders, such as cable-stayed or tied-arch bridges, needs deep study of the prestressing forces to be applied to stays or hangers in all stages, depending on the construction technique adopted. In these cases, the main issue is the determination of the initial forces and optimization of the prestressing system in terms of stressing values and sequence. When the bridge is already built and suspenders have to be replaced for maintenance, a different problem has to be faced by the engineer, because the sequence of replacements and the values of the axial stresses depend very much on the service conditions of the bridge and on its historical evolution from co…