Numerical simulation of a water infiltration test on a proposed backfill material in nuclear waste repositories

A water infiltration test was numerically simulated using the finite element method. The modified Barcelona Basic Model and the double-structure water retention model was used for the numerical analysis. A methodology is presented for parameter identification and calibration purpose. The experimental results highlighted the porosity redistribution and hydration-induced heterogeneity along the hydration-path. The simulation results successfully captured the moisture migration in the soil sample. A comparison between the measured and predicted total stress values revealed the influence of interfacial friction between the soil sample and cell wall.

Neutron spectroscopy from 1 to 15 MeV with Mimac-FastN, a mobile and directional fast neutron spectrometer and an active phantom for BNCT and PFBT

In the frame of direct dark matter search, the fast neutrons producing elastic collisions on the nuclei of the active volume are the ultimate background. The MIMAC (MIcro-tpc MAtrix Chambers) project has developed a directional detector providing the directional signature to discriminate them from the searched events based on 3D nuclear tracks reconstruction. The MIMAC team of the LPSC has adapted one MIMAC chamber as a mobile fast neutron spectrometer, the Mimac-FastN detector, having a wide neutron energy range (10 keV – 600 MeV) working with different gas mixtures and pressures. This presentation will be focused on the MeV range with 4He + 5% CO2 gas mixture at 700 mbar. A boron coating inside the active volume used for calibration purpose opens the possibility to use the active volume as an active phantom for Boron Neutron Capture Therapy (BNCT) and Proton Fusion Boron Therapy (PFBT).

Development Of Test Rig System For Calibration Of Temperature Sensing Fabric

A test rig is described, for the measurement of temperature and resistance parameters of a Temperature Sensing Fabric (TSF) for calibration purpose. The equipment incorporated a temperature-controlled hotplate, two copper plates, eight thermocouples, a temperature data-logger and a four-wire high-resolution resistance measuring multimeter. The copper plates were positioned above and below the TSF and in physical contact with its surfaces, so that a uniform thermal environment might be provided. The temperature of TSF was estimated by the measurement of temperature profiles of the two copper plates. Temperature-resistance graphs were created for all the tests, which were carried out over the range of 20 to 50°C, and they showed that the temperature and resistance values were not only repeatable but also reproducible, with only minor variations. The comparative analysis between the temperature-resistance test data and the temperature-resistance reference profile showed that the error in estimation of temperature of the sensing element was less than ±0.2°C. It was also found that the rig not only provided a stable and homogenous thermal environment but also offered the capability of accurately measuring the temperature and resistance parameters. The Temperature Sensing Fabric is suitable for integration into garments for continuous measurement of human body temperature in clinical and non-clinical settings.

A Method to Calculate the Net Power Delivered into a TEM Cell Using a Directional Coupler in a Probe Calibration Application

In a probe calibration facility employing the TEM cell as the field generator, a method to calculate the net power delivered into the TEM cell is presented through monitoring the coupling power of the directional coupler. The new formula requires the effective reflection coefficient of the dual coupler and takes into consideration the directivity of the coupler, the mismatch between the coupler and the TEM cell, the mismatch between the power sensor and the coupling port of the coupler. The formula can provide sufficient accuracy in calibration purpose application using a TEM cell with a coupler combined with power sensors to monitor the net power.

Embedded Sensor for Detecting Corrosion of Reinforcement in Concrete

Corrosion of reinforcement is a worldwide problem which causes premature degradations in reinforced concrete structures. Monitoring reinforcement corrosion in concrete can be achieved by embedding corrosion sensor within the concrete cover. In this research, capacitance-based embedded sensor was developed to monitor corrosion potential (Ecorr) and corrosion rate (Icorr) parameters of reinforcement continuously. The sensors were tied to the reinforcement and embedded in concrete slab specimens followed by immersion into NaCl solution for 70 days. During this period, corrosion parameters were weekly recorded. At the same time, half-cell corrosion testing using Portable SRI-CMIII was conducted for calibration purpose. From the research, it was observed that the patterns ofEcorrandIcorrshown by the embedded sensors were similar to that of portable SRI-CMIII device - an indication of suitability of the embedded sensor towards sensing existing corrosion activities around the embedded steel bars. Eventually, the bars were found corroded from the broken specimens to confirm the detection of corrosion activities as recorded by the sensors.