206 research outputs found
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Imperfect inspection characterization for gamma process structural deterioration model
The deterioration of infrastructure facilities such as bridges has raised concerns over objective methodology to quantify the changes in their safety levels during the service life. In this paper the novel modeling of existing reinforced concrete structures likely future deterioration of strength is of interest. It is assumed that inspection outcomes are the source of data about the deterioration process and should provide help with the updating of the deterioration model with respect to the current structural condition. However, the inspection outcomes are associated with uncertainties that need to be taken into account for deterioration modeling. Sample reinforced concrete structure deterioration process is characterized as a time-dependent, non-negative and incremental process. In this paper we follow recent developments and the continuous gamma process has been adopted to represent the mathematical model of the deterioration process. In the current study two data sources were considered, the expert opinion, which is considered to reflect 'perfect inspection' and data obtained through scheduled inspections as 'imperfect inspection'. This paper reports on early development of the model to quantify the measurement error as inspection uncertainty and to establish continuous gamma process parameters for future deterioration prediction
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Stochastic process deterioration modelling for adaptive inspections
In this paper we have considered an option to model deterioration process for infrastructure components using stochastic process representation as an alternative to random variable modelling that is prevalent approach when uncertainty is taken into account. In particular, we have identified that a Gamma process represents a very simple and effective method to establish consistent deterioration models for structures that are subject to inspection. As a result of such approach we see an opportunity to establish adaptive inspection regimes that would account much better for the structure specific deterioration path, site specific environment, in service inspection outcomes, inspection technique effectiveness, etc. An example is presented to demonstrate deterioration modelling and further work is identified
Linear wave dynamics explains observations attributed to dark-solitons in a polariton quantum fluid
We investigate the propagation and scattering of polaritons in a planar GaAs
microcavity in the linear regime under resonant excitation. The propagation of
the coherent polariton wave across an extended defect creates phase and
intensity patterns with identical qualitative features previously attributed to
dark and half-dark solitons of polaritons. We demonstrate that these features
are observed for negligible nonlinearity (i.e., polariton-polariton
interaction) and are, therefore, not sufficient to identify dark and half-dark
solitons. A linear model based on the Maxwell equations is shown to reproduce
the experimental observations.Comment: Article + Supplementary Information (tot. 18 pages
Core promoter short tandem repeats as evolutionary switch codes for primate speciation
Alteration in gene expression levels underlies many of the phenotypic differences across species. Because of their highly mutable nature, proximity to the +1 transcription start site (TSS), and the emerging evidence of functional impact on gene expression, core promoter short tandem repeats (STRs) may be considered an ideal source of variation across species. In a genome-scale analysis of the entire Homo sapiens protein-coding genes, we have previously identified core promoters with at least one STR of ≥6-repeats, with possible selective advantage in this species. In the current study, we performed reverse analysis of the entire Homo sapiens orthologous genes in mouse in the Ensembl database, in order to identify conserved STRs that have shrunk as an evolutionary advantage to humans. Two protocols were used to minimize ascertainment bias. Firstly, two species sharing a more recent ancestor with Homo sapiens (i.e. Pan troglodytes and Gorilla gorilla gorilla) were also included in the study. Secondly, four non-primate species encompassing the major orders across Mammals, including Scandentia, Laurasiatheria, Afrotheria, and Xenarthra were analyzed as out-groups. We introduce STR evolutionary events specifically identical in primates (i.e. Homo sapiens, Pan troglodytes, and Gorilla gorilla gorilla) vs. non-primate out-groups. The average frequency of the identically shared STR motifs across those primates ranged between 0.00005 and 0.06. The identified genes are involved in important evolutionary and developmental processes, such as normal craniofacial development (TFAP2B), regulation of cell shape (PALMD), learning and long-term memory (RGS14), nervous system development (GFRA2), embryonic limb morphogenesis (PBX2), and forebrain development (APAF1). We provide evidence of core promoter STRs as evolutionary switch codes for primate speciation, and the first instance of identity-by-descent for those motifs at the interspecies level. © 2014 Wiley Periodicals, Inc
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Adaptive inspection regime for reinforced concrete short to medium span bridges with stochastic deterioration
Bridge components are subjected to deterioration factors such as aggressive environment, corrosion, chemical attack etc. that can result in a loss of load capacity and life span. In order to keep the safety of the bridge at an appropriate level inspection regimes are followed.
This thesis concern is to establish an adaptive inspection regime for reinforced short to medium span concrete bridges. Our emphasis is mainly on using the information about the deterioration progress to determine efficient inspection regime.
An updatable structural deterioration model that follows the inspection outcomes is developed. A stationary continuous Gamma process is used to develop the structural deterioration model. In order to predict the deterioration profile of bridge slab, deterioration process of a reinforced concrete slab subject to corrosion is modeled using Gamma process through the thesis. Inspection outcomes at specific ages are used to update the deterioration model. The updated deterioration model reflects the latest condition of component at inspection time. Different deterioration condition such as initiation time and deterioration rate are considered in thesis and influence of deterioration condition on deterioration process is represented.
Initially it is assumed that the observed inspection outcomes are perfect. It is identified that the inspection outcomes are associated with uncertainties. In order to characterize the probability of detection and measurement error as inspection outcomes uncertainties, the probabilistic model is implemented. A new probabilistic framework is developed to take into account uncertainties associated with inspection outcomes. The deterioration model is applied following the actual inspection outcomes to reflect the influence of the inspection outcomes uncertainties. Finally a new adaptive inspection regime is established based on the actual deterioration profile. An efficient inspection regime is established as result. The novel probabilistic method is highly flexible and can be implemented in different countries with different environments
Novel designs for Penning ion traps
We present a number of alternative designs for Penning ion traps suitable for
quantum information processing (QIP) applications with atomic ions. The first
trap design is a simple array of long straight wires which allows easy optical
access. A prototype of this trap has been built to trap Ca+ and a simple
electronic detection scheme has been employed to demonstrate the operation of
the trap. Another trap design consists of a conducting plate with a hole in it
situated above a continuous conducting plane. The final trap design is based on
an array of pad electrodes. Although this trap design lacks the open geometry
of the traps described above, the pad design may prove useful in a hybrid
scheme in which information processing and qubit storage take place in
different types of trap. The behaviour of the pad traps is simulated
numerically and techniques for moving ions rapidly between traps are discussed.
Future experiments with these various designs are discussed. All of the designs
lend themselves to the construction of multiple trap arrays, as required for
scalable ion trap QIP.Comment: 11 pages, 10 figure
Ultralong temporal coherence in optically trapped exciton-polariton condensates
Funding: This work was supported by Grant No. EPSRC EP/S014403/1. K.O. acknowledges EPSRC for PhD studentship support through grant no. EP/L015110/1. P.S. acknowledges support by Westlake University (Project No. 041020100118), Program 2018R01002 supported by Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang, and bilateral Greece-Russia Polisimulator project co-financed by Greece and the EU Regional Development Fund.We investigate an optically trapped exciton-polariton condensate and observe temporal coherence beyond 1 ns in duration. Due to the reduction of the spatial overlap with the thermal reservoir of excitons, the coherence time of the trapped condensate is more than an order of magnitude longer than that of an untrapped condensate. This ultralong coherence enables high-precision spectroscopy of the trapped condensate, and we observe periodic beats of the field correlation function due to a fine energy splitting of two polarization modes of the condensate. Our results are important for realizing polariton simulators with spinor condensates in lattice potentials.PostprintPeer reviewe
Molecular study of PKD1 & PKD2 genes by linkage analysis and determining the genotype/phenotype correlations in several Iranian families with autosomal dominant polycystic kidney disease
Background: Autosomal dominant polycystic kidney disease (ADPKD) is an inherited disorder with genetic heterogeneity. Up to three loci are involved in this disease, PKD1 on chromosome 16p 13.3, PKD2 on 4q21, and a third locus of unknown location. Methods: Here we report the first molecular genetic study of ADPKD and the existence of locus heterogeneity for ADPKD in the Iranian population by performing linkage analysis on 15 affected families. Results: Eleven families showed linkage to PKD1 and two families showed linkage to PKD2. In two families, PKD1 markers are common in all affected members but PKD2 markers were not informative. Conclusion: The results of this study demonstrate significant locus heterogeneity in autosomal dominant PKD in Iran. Analysis of clinical data confirms a milder ADPKD phenotype for PKD2 families. Our results showed relatively high heterozygosity rates and PIC values for some markers, while the most informative markers were KG8 and 16AC2.5 for PKD1 gene and AFM224x6 for PKD2 gene
Enhanced frequency up-conversion in Rb vapor
We demonstrate highly efficient generation of coherent 420nm light via
up-conversion of near-infrared lasers in a hot rubidium vapor cell. By
optimizing pump polarizations and frequencies we achieve a single-pass
conversion efficiency of 260% per Watt, significantly higher than in previous
experiments. A full exploration of the coherent light generation and
fluorescence as a function of both pump frequencies reveals that coherent blue
light is generated close to 85Rb two-photon resonances, as predicted by theory,
but at high vapor pressure is suppressed in spectral regions that do not
support phase matching or exhibit single-photon Kerr refraction. Favorable
scaling of our current 1mW blue beam power with additional pump power is
predicted.Comment: 6 pages, 4 figures. Modified to include referees' improvement
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