We report on recent results by the CMS Collaboration on searches for supersymmetry based on a sample of proton-proton collision data at √s = 13 TeV, corresponding to a total integrated luminosity of ...35.9 fb
-1
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The spreading of deicing salt on roads during winter and the consequent migration of chloride ions within concrete exposes structures reinforcement to corrosion. Reinforcement corrosion is ...problematic because it reduces the structure's load carrying capacity and a long-term consequence can be structural failure. The use of Ground Penetrating Radar (GPR) technology is commonly applied to reinforced concrete structural mapping. This paper provides methodologies for the calculation of the electromagnetic parameters from GPR data accounting for chloride content and its distribution within concrete. The previous work showed that they are linked with water and chloride content. A GPR dataset was carried out with bi-static off-ground GPR antennas during an experiment recreating chloride contamination processes in concrete specimens. Two novel solutions are presented in this paper, their use on the dataset returned the electromagnetic parameters of the concrete specimens with knowledge of their thickness. Firstly, a ray-based approach is provided as a fast computational tool to determine average material properties. Thereafter, a novel full-waveform inversion based on a multilayered forward model is presented. It allows the identification of conductivity gradients present inside the concrete. Finally, the results are compared with additional destructive testing; they present a good correspondence.
Processing strategies for high-resolution GPR concrete inspections Hugenschmidt, Johannes; Kalogeropoulos, Alexis; Soldovieri, Francesco ...
NDT & E international : independent nondestructive testing and evaluation,
06/2010, Letnik:
43, Številka:
4
Journal Article
Recenzirano
A high-resolution multi-sensor and multi-polarization Ground Penetrating Radar (GPR) dataset was acquired on a concrete retaining wall. This dataset was characterised as a low pass filter with the ...help of a moving window spectral analysis. In order to examine the benefits and limits of innovative processing strategies, the dataset was processed with three different methods: classical 2-D processing, full 3-D processing followed by data fusion and inverse scattering followed by data fusion. A comparison of the results for two layers of rebar present in the wall shows that the innovative approaches improve the results for near surface structures when compared to classical 2-D processing. For deeper structures, the benefits of the innovative approaches are limited because of the low pass properties of the concrete.
Undisputedly, derivation of theoretical systematic uncertainties is an inseparable ingredient of any robust analysis dealing with experimental data. However, it is not uncommon, even for those ...analyses that use state of the art methods and tools to suffer from insufficient statistics when it comes to the simulated datasets used to estimate systematic uncertainties. This practically limits the power, and sometimes the robustness of the analysis. In this paper, we present SysCalc, a code which is able to derive weights for various important theoretical systematic uncertainties, including those related to the choice of the Parton Distribution Function sets and the various scale choices. SysCalc utilizes the central sample generated events to estimate the related systematic uncertainties, thus, omitting the need for generating dedicated systematics datasets, and with only a minimal added cost in terms of computing resources. In this paper we discuss the working principles of the code accompanied by various validation plots. We also discuss the structure of the code followed by a practical guide for how to use the tool.
To study the sonographic evolutaion of the chorionic tissue projection at the intertwin membrane-placental junction, or lambda sign, or twin-chorionic peak sign, in dichorionic twin pregnancies and ...to determine the effect of placental location on its prevalence during the first half of pregnancy.
We prospectively recruited women with twin pregnancies undergoing sonographic screening for chromosomal abnormalities at 10-14 weeks' gestation for this study. The presence or absence of the lambda sign and the position of the placenta(s) were recorded in all cases. The presence of the lambda sign was evaluated prospectively at 16 and 20 weeks' gestation.
There were 101 twin pregnancies with a lambda sign identified at 10-14 weeks' gestation, 67 with fused placentas and 34 with separate placentas. At 16 weeks, the lambda sign was present in all 67 pregnancies with fused placentas (100%) and in 31 of 34 (91%) pregnancies with separate placentas. At 20 weeks, the lambda sign was present in 25 of the 34 (74%) pregnancies with separate placentas and in 62 of the 67 (93%) with fused placentas. The lambda sign was identified subsequently in none of the 53 pregnancies in which it was absent at 10-14 weeks' gestation.
At 10-14 weeks' gestation, twin pregnancies with the lambda sign can be classified as dichorionic and pregnancies with absent lambda sign can be classified as monochorionic and therefore monozygotic. At 16-20 weeks, the lambda sign is indicative of dichorionicity but its absence does not exclude dizygosity.
The assessment of ageing concrete structures is a major technical challenge faced by the Civil Engineers of today. Concrete bridges are exposed to corrosion from the spreading of de-icing salts on ...roads during winter. Corrosion is problematic because it reduces the reinforcement's load carrying capacity and a long-term consequence can be structural failure. This paper describes an experiment that consisted in exposing a concrete specimen to a controlled wetting-drying cycle using a saline solution. This setup enabled the concentration of chlorides to be distributed in gradients inside the specimen. A novel methodology to estimate material properties, based on ground penetrating radar (GPR) full-waveform inversion, was used to process GPR traces. In this paper, each reflection present in the trace was regarded independently. This procedure was applied to a dataset acquired with bistatic off-ground GPR antennas. Measurements were carried out above the test specimen at regular time lapses. This allowed monitoring of the electromagnetic parameters of the top and bottom concrete specimen surfaces during the wetting-drying cycle.
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