In-situ steel solidification imaging in continuous casting using magnetic induction tomography

: Solidification process in continuous casting is a critical part of steel production. The speed and quality of the solidification process determines the quality of final product. Computational fluid dynamics (CFD) simulations are often used to describe the process and design of its control system, but so far, there is no any tool that provides an on-line measurement of the solidification front of hot steel during the continuous casting process. This paper presents a new tool based on magnetic induction tomography (MIT) for real time monitoring of this process. The new MIT system was installed at the end of the secondary cooling chamber of a casting unit and tested during several days in a real production process. MIT is able to create an internal map of electrical conductivity of hot steel deep inside the billet. The image of electrical conductivity is then converted to temperature profile that allows the measurement of the solid, mushy and liquid layers. In this study, such a conversion is done by synchronizing in one time step the MIT measurement and the thermal map generated with the actual process parameters available at that time. The MIT results were then compared with the results obtained of the CFD and thermal modelling of the industrial process. This is the first in-situ monitoring of the interior structure during a real continuous casting.The SHELL-THICK project has received funding from EU Research Fund for Coal and Steel under grant number 709830. This study reflects only the author's views and the European Commission is not responsible for any use that may be made of the information contained therein

Ultrasound Brain Tomography:Comparison of Deep Learning and Deterministic Methods

— The general purpose of this document is to develop a lightweight, portable ultrasound computer tomography (USCT) system that enables noninvasive imaging of the inside of the human head with high resolution. The goal is to analyze the benefits of using a deep neural network containing convolutional neural network (CNN) and long short-term memory (LSTM) layers compared to deterministic methods. In addition to the CNN + LSTM and LSTM networks, the following methods were used to create tomographic images of the inside of the human head: truncated singular value decomposition (TSVD), linear backprojection (LB), Gauss–Newton (GN) with regularization matrix, Tikhonov regularization (TR), and Levenberg–Marquardt (LM). A physical model of the human head was made. Based on synthetic and real measurements, images of the inside of the brain were reconstructed. On this basis, the CNN + LSTM and LSTM methods were compared with deterministic methods. Based on the comparison of images and quantitative indicators, it was found that the proposed neural network is much more tolerant of noisy and nonideal synthetic data measurements, which is manifested in the lack of the need to apply filters to the obtained images. An important finding confirmed by hard evidence is the confirmation of the greater usefulness of neural models in medical ultrasound tomography, which results from the generalization abilities of the deep hybrid neural network. At the same time, research has shown a deficit of these abilities in deterministic methods. Considering the human head’s specificity, using hybrid neural networks containing both CNN and LSTM layers in clinical trials is a better choice than deterministic methods.</p

A 3D multi-frequency response electrical mesh phantom for validation of the planar structure EIT system performance

Assessment and validation of the Electrical Impedance Tomography (EIT) system performance and calibration of systematic errors in the electrical field generated inside of the interrogated volume is an important requirement. System instabilities can be caused by the EIT design and must be characterized before and during the clinical trials. Evaluation of the Sussex EIT system used in the clinical study can be based on a realistic electronic phantom. We designed a mesh phantom based on the electrode configuration and mesh structures of the image reconstruction. The phantom has the capability of modelling the cellular electrical properties that are operative within a circular homogeneous medium. The design is optimized to assess the planar topology of the internal impedance distribution. The system employs the information from the electrical properties of biological tissues to evaluate the Cole-Cole dispersion data. This mesh phantom is capable of producing localized conductivity perturbations between each arbitrary channel in the electrode placement planar phantom topology by measuring all 1416 combinations that are to be used in the image reconstruction. The phantom is especially designed for the Sussex EIT system to validate system performance of measurements consisting of SNR, and modelling system accuracy

Safety evaluation of chloramine-T on ornamental zebra fish (Danio rerio) using LC50 calculation and organ pathology

The need of aquarists for proper and safe disinfection of fish with Chloramine-T (CL-T) necessitates toxico/pathologic examinations. This study assays toxicity level of CL-T and histopathologic changes of gills, liver, kidney and brain of treated zebrafish (Danio rerio). Groups of 10 Zebrafish were treated with 0 (control), 5, 10, 15, 30, 50, 100 and 200 mg/L of CL-T. Mortality was recorded at every 6 hours until 96h after the beginning of the treatment and lethal concentration for 50% of population (LC50 at 24h and 96h) was calculated. The histopathologic samples were taken from dying fish during the exposure period. Histopathological changes were not evident in organs of the control group. In the gills of treatment groups, congestion, edema, separation of epithelium of secondary lamella from basal membrane, fusion and hypertrophy of secondary lamella, telangiectasis and necrosis of lamella epithelium were observed. In the liver of treatment groups degenerative changes and necrosis of hepatocytes were visible. The kidney samples represented hydropic degeneration, necrosis, dilation of periglomerular urinary space and hyaline droplets in renal tubules in high concentration. The brain of treatment groups showed spongiosis and increase in glial cells. Severity of these lesions was related to the concentration of CL-T. LC50 24h for CL-T was 428.649 mg/L and LC50 96h was 11.044 mg/L which reveals the low level of toxicity for few hours of treatment. The concentrations below 15mg/L are reasonably safe and recommended for usage in D. rerio treatment during 24h of bath

Motion-compensated cone beam computed tomography using a conjugate gradient least-squares algorithm and electrical impedance tomography imaging motion data

Cone beam computed tomography (CBCT) is an imaging modality that has been used in image-guided radiation therapy (IGRT). For applications such as lung radiation therapy, CBCT images are greatly affected by the motion artefacts. This is mainly due to low temporal resolution of CBCT. Recently, a dual modality of electrical impedance tomography (EIT) and CBCT has been proposed, in which the high temporal resolution EIT imaging system provides motion data to a motion-compensated algebraic reconstruction technique (ART)-based CBCT reconstruction software. High computational time associated with ART and indeed other variations of ART make it less practical for real applications. This paper develops a motion-compensated conjugate gradient least-squares (CGLS) algorithm for CBCT. A motion-compensated CGLS offers several advantages over ART-based methods, including possibilities for explicit regularization, rapid convergence and parallel computations. This paper for the first time demonstrates motion-compensated CBCT reconstruction using CGLS and reconstruction results are shown in limited data CBCT considering only a quarter of the full dataset. The proposed algorithm is tested using simulated motion data in generic motion-compensated CBCT as well as measured EIT data in dual EIT–CBCT imaging.</jats:p

SUSY dark matter and lepton flavor violation

We study lepton flavor-violating (LFV) processes within a supersymmetric type-I seesaw framework with flavor-blind universal boundary conditions, properly accounting for the effect of the neutrino sector on the dark matter relic abundance. We consider several possibilities for the neutrino Yukawa coupling matrix and show that in regions of SUSY parameter space that yield the correct neutralino relic density, LFV rates can differ from naive estimates by up to two orders of magnitude. Contrary to common belief, we find that current LFV limits do not exclude neutrino Yukawa couplings larger than top Yukawa couplings. We introduce the ISAJET-M program that was used for the computations.Comment: 37 pages, 9 figures, 6 tables. Version to appear in PR