Evaluating the Damage Content of Karbandi Using Frequency Domain Analysis (Case Study: Timche Haj-Mohammad-Qoli of Tabriz Historic Bazaar)

In this study, an alternate method of evaluating structural systems, especially for the sensitive structures with historical importance by applying Fourier Transform (FT) to the damage ratio of time history outcome in the frequency domain has been introduced. The concept of damage content (DC) regarding the mechanical characteristics of the used material, including plastic strain, failure plane, and ultimate load-bearing capacity, along with drift value, record selection criteria, and architectural aspects, have been employed. Due to its valuable aesthetic and architectural view, Timche Haj-Mohammad-Qoli of Tabriz Historic Bazaar, one of the traditional covered spaces with the complicated configuration of spatial masonry intersecting arches, was selected for the assessment in the current study. The required experimental samples for obtaining the mechanical properties and relevant geometrical measurements to prepare the numerical model of the structure obtained. The strong ground motions according to seismological and geological characteristics of the construction site selected. The records with different durations were merged by Fourier Transform (FT) and Damage Content (DC) analysis. According to the outcomes, the damage state of the structure due to the imposed strong motion at every stage of the lateral loading from the failure initiation to the final collapse was observable. As a direct outcome of this study, the vulnerability concerning the near-field earthquakes is more tangible than far-field earthquakes. The provided methodology could have proper use in future similar studies for evaluating the performance of the structures.

Predicting DNA damage foci and their experimental readout with 2D microscopy: a unified approach applied to photon and neutron exposures

The consideration of how a given technique affects results of experimental measurements is a must to achieve correct data interpretation. This might be challenging when it comes to measurements on biological systems, where it is unrealistic to have full control (e.g. through a software replica) of all steps in the measurement chain. In this work we address how the effectiveness of different radiation qualities in inducing biological damage can be assessed measuring DNA damage foci yields, only provided that artefacts related to the scoring technique are adequately considered. To this aim, we developed a unified stochastic modelling approach that, starting from radiation tracks, predicts both the induction, spatial distribution and complexity of DNA damage, and the experimental readout of foci when immunocytochemistry coupled to 2D fluorescence microscopy is used. The approach is used to interpret γ-H2AX data for photon and neutron exposures. When foci are reconstructed in the whole cell nucleus, we obtain information on damage characteristics “behind” experimental observations, as the average damage content of a focus. We reproduce how the detection technique affects experimental findings, e.g. contributing to the saturation of foci yields scored at 30 minutes after exposure with increasing dose and to the lack of dose dependence for yields at 24 hours.

Influence of Ar Implantation on the Precipitation in Au Ion Irradiated AISI 316L Solution Annealed Alloy

ABSTRACT200 μm thick solution annealed AISI 316L stainless steel foils were implanted with Ar ions to produce a 0.25 at. % concentration-depth plateau extending from the near surface to a depth of ≈ 250 nm, and then annealed at 550°C for 2 hours to form small Ar bubbles and Ar-vacancy clusters. Distinct sets of samples (including control ones without Ar) were irradiated at the temperature of 550 °C with Au ions accelerated at 5 MeV to produce an average damage content about ≈36 dpa at the region containing the Ar plateau. These samples were investigated by transmission electron microscopy using plan-view specimens prepared by ion milling. In contrast with the control samples where the irradiation causes the formation of a high concentration of extended defects and large cavities, carbonite precipitation of 1:1 metal-carbon (MC) content with a cubic structure occurs only in the samples containing the Ar bubbles. This precipitation phenomenon is not commonly observed in the literature. The results are interpreted considering that the precipitate growth process requires the emission of vacancies which are synergistically absorbed by the growth of the Ar bubbles.