Structural identification of Humber Bridge for performance prognosis

Copyright © 2015 Techno-Press, Ltd.Structural identification or St-Id is 'the parametric correlation of structural response characteristics predicted by a mathematical model with analogous characteristics derived from experimental measurements'. This paper describes a St-Id exercise on Humber Bridge that adopted a novel two-stage approach to first calibrate and then validate a mathematical model. This model was then used to predict effects of wind and temperature loads on global static deformation that would be practically impossible to observe. The first stage of the process was an ambient vibration survey in 2008 that used operational modal analysis to estimate a set of modes classified as vertical, torsional or lateral. In the more recent second stage a finite element model (FEM) was developed with an appropriate level of refinement to provide a corresponding set of modal properties. A series of manual adjustments to modal parameters such as cable tension and bearing stiffness resulted in a FEM that produced excellent correspondence for vertical and torsional modes, along with correspondence for the lower frequency lateral modes. In the third stage traffic, wind and temperature data along with deformation measurements from a sparse structural health monitoring system installed in 2011 were compared with equivalent predictions from the partially validated FEM. The match of static response between FEM and SHM data proved good enough for the FEM to be used to predict the un-measurable global deformed shape of the bridge due to vehicle and temperature effects but the FEM had limited capability to reproduce static effects of wind. In addition the FEM was used to show internal forces due to a heavy vehicle to to estimate the worst-case bearing movements under extreme combinations of wind, traffic and temperature loads. The paper shows that in this case, but with limitations, such a two-stage FEM calibration/validation process can be an effective tool for performance prognosis.Engineering and Physical Sciences Research Council (EPSRC

The identification of a novel, high frequency variant in the Cytochrome b gene in an isolated population of a rare fish, Spined Loach Cobitis taenia, in England: A population worth protecting?

The spined loach Cobitis taenia, is listed as a protected species under Appendix 3 of the Bern Convention and Annex II of the European Council Directive (92/43/EEC) on the conservation of natural habitats and of wild fauna and flora. It is desirable therefore to understand the genetic diversity within European populations. In a molecular genetic analysis of the cytochrome b gene in Cobitis taenia from three sites in the upper reaches of the River Trent catchment, a novel high frequency variant was identified which has not been previously reported in any European or Non-European population

Attracted Diffusion-Limited Aggregation

In this paper, we present results of extensive Monte Carlo simulations of diffusion-limited aggregation (DLA) with a seed placed on an attractive plane as a simple model in connection with the electrical double layers. We compute the fractal dimension of the aggregated patterns as a function of the attraction strength \alpha. For the patterns grown in both two and three dimensions, the fractal dimension shows a significant dependence on the attraction strength for small values of \alpha, and approaches to that of the ordinary two-dimensional (2D) DLA in the limit of large \alpha. For non-attracting case with \alpha=1, our results in three dimensions reproduce the patterns of 3D ordinary DLA, while in two dimensions our model leads to formation of a compact cluster with dimension two. For intermediate \alpha, the 3D clusters have quasi-2D structure with a fractal dimension very close to that of the ordinary 2D-DLA. This allows one to control morphology of a growing cluster by tuning a single external parameter \alpha.Comment: 6 pages, 6 figures, to appear in Phys. Rev. E (2012

Safety Issues Improvement in Ceramic Lined Composite Pipe Produced Using SHS Method

Abstract Self-Propagating High-Temperature Synthesis (SHS) or combustion synthesis (CS) is an advanced method for producing high temperature materials such as refractory materials, intermetallics, and cermets. Combustion synthesis is characterized by extremely heating rate, high temperatures, and short reaction times. Centrifugal force densification was employing to produce dense ceramic-lined steel pipes. The centrifugal force facilitates phase separation of multi-component products during the process. In this research the safety matters in producing ceramiclined composite pipes from Fe 2 O 3 -Al powder mixture is studied. A SHS centrifugal machine with the acceleration up to a = 350g was developed. Thermite reaction of Fe 2 O 3 and Al was occurred inside the pipe to produce Al 2 O 3 ceramic in the innermost layer and Fe layer at a region between the outer steel pipe and the ceramic layer

Shock-Boundary Layer Interactions in Supersonic Turbine Cascades

The physics of shock-boundary layer interactions in a supersonic turbine cascade is investigated through a wall-resolved large eddy simulation. Special attention is given to the characterization of the low-frequency dynamics of the separation bubbles using flow visualization, spectral analysis, space-time cross correlations, and flow modal decomposition. The mean flowfield shows different shock structures formed on both sides of the airfoil. On the suction side, an oblique shock impinges on the turbulent boundary layer, whereas a Mach reflection interacts with the pressure side boundary layer. Instantaneous flow visualizations illustrate elongated streamwise structures on the incoming boundary layers and their interactions with the shocks and separation bubbles. The passage of high-speed (low-speed) streaks through the recirculation bubbles leads to the downstream (upstream) motion of the separation point on both suction and pressure sides, resulting in spanwise modulation of the bubbles. Space-time cross-correlations reveal that the near-wall streaks drive the suction side separation bubble motion, which in turn promotes the oscillations of the reattachment shock and shear layer flapping. Space-time correlations also indicate the existence of a $\pi$ phase jump in the pressure fluctuations along the separation bubble on the suction side. After this phase jump, a downstream propagating pressure disturbance is observed, while prior to this point, the pressure disturbances dominantly propagate in the upstream direction. Finally, the organized motions in the shock-boundary layer interactions and their corresponding characteristic frequencies are identified using proper orthogonal decomposition.Comment: 40 pages, 19 figures. Submitted to Physical Review Fluid

Transduction‐Specific ATLAS Reveals a Cohort of Highly Active L 1 Retrotransposons in Human Populations

L ong IN terspersed E lement‐1 ( LINE ‐1 or L 1) retrotransposons are the only autonomously active transposable elements in the human genome. The average human genome contains ∼80–100 active L1s, but only a subset of these L1s are highly active or ‘hot’. Human L1s are closely related in sequence, making it difficult to decipher progenitor/offspring relationships using traditional phylogenetic methods. However, L1 m RNA s can sometimes bypass their own polyadenylation signal and instead utilize fortuitous polyadenylation signals in 3′ flanking genomic DNA . Retrotransposition of the resultant m RNA s then results in lineage specific sequence “tags” (i.e., 3′ transductions) that mark the descendants of active L1 progenitors. Here, we developed a method (Transduction‐Specific Amplification Typing of L1 Active Subfamilies or TS ‐ ATLAS ) that exploits L1 3′ transductions to identify active L1 lineages in a genome‐wide context. TS ‐ ATLAS enabled the characterization of a putative active progenitor of one L1 lineage that includes the disease causing L1 insertion L1 RP , and the identification of new retrotransposition events within two other “hot” L1 lineages. Intriguingly, the analysis of the newly discovered transduction lineage members suggests that L1 polyadenylation, even within a lineage, is highly stochastic. Thus, TS ‐ ATLAS provides a new tool to explore the dynamics of L1 lineage evolution and retrotransposon biology. Long INterspersed Element‐1 (L1) retrotransposons are the only independently mobile elements in the human genome. We developed Transduction‐Specific Amplification Typing of L1 Active Subfamilies (TS‐ATLAS), which utilizes L1‐transduced genomic sequences, to identify a subset of highly active L1s genome‐wide. TS‐ATLAS enabled the characterization of the putative progenitor of an active disease‐causing L1 lineage, and identified new retrotransposition events within two other “hot” L1 lineages.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98809/1/humu22327.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/98809/2/humu22327-sup-0001-si.pd

Attitudes toward brushing children's teeth—A study among parents with immigrant status in Norway

Background Early childhood caries (ECC) is a common chronic childhood disease with multifactorial etiology including poor parental dietary and hygiene behaviors. Aim This study aimed to assess toothbrushing‐related perceptions among parents with immigrant background living in Norway. Design A structured interview was performed with immigrant parents to assess their oral health‐related knowledge, beliefs, and attitude toward toothbrushing. Immigrant parents of non‐Western origin with newborn infants (0‐6 months) were included in this study. Results Of those interviewed, 66% chose to participate and they were found to have an average favorable attitudes, subjective norms, and strong perceptions of control related to child's tooth brushing with reported means of (3.3), (3.6), and (4.6), respectively. They had on average low indulgence (mean 7.8) with respect to this behavior and a relatively high level of knowledge (mean 6.9). Parents with strong intention toward toothbrushing (61%) had on average more frequent oral hygiene behavior than parents with weak intentions. Conclusion Parents with non‐Western origin have adequate knowledge and intention toward toothbrushing, although some have an unsatisfactory attitude, which might affect the oral health of their children negatively. Culture and habits are contributing factors in ECC and should be addressed in oral health prevention policies.publishedVersio

Facile Preparation of Drug-Loaded Tristearin Encapsulated Superparamagnetic Iron Oxide Nanoparticles Using Coaxial Electrospray Processing

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link