Detection of impact damage in CARBON-FIBRE Composites using an electromagnetic sensor

This article presents a comprehensive experimental study of impact damage detection for carbon fiber-reinforced polymer (CFRP) composites using an electromagnetic (EM) sensor with coupled spiral inductors (CSI). Two representative types of damage are detected and evaluated, i.e., barely visible impact damage (BVID) and delamination. A multifrequency inspection is performed, where the resultant images indicate the potential of the CSI sensor in the characterization of damage extent. The accuracy and efficiency of the CSI sensor are compared with the open-ended waveguide imaging, near-field microwave microscopy, microwave time-domain reflectometry, the complementary split-ring resonator, and ultrasonic scanning. Applications and limitations of these nondestructive testing (NDT) methods for identifying impact damage are discussed. There is a free edge effect on the electromagnetic signal, which is illustrated for the first time with the proposed EM technique. Detection of the air gap produced by inserting a thin piece into a machined subsurface groove is carried out. It is found that the developed CSI sensor is able to accurately resolve the location and extent of the air gap. The experimental results demonstrate that the sensor could offer an alternative relatively low cost method that can be fully automated for structural monitoring of aircraft and other composite structures

Modeling pure methane hydrate dissociation using a numerical simulator from a novel combination of X-ray computed tomography and macroscopic data

The numerical simulator TOUGH+HYDRATE (T+H) was used to predict the transient pure methane hydrate (no sediment) dissociation data. X-ray computed tomography (CT) was used to visualize the methane hydrate formation and dissociation processes. A methane hydrate sample was formed from granular ice in a cylindrical vessel, and slow depressurization combined with thermal stimulation was applied to dissociate the hydrate sample. CT images showed that the water produced from the hydrate dissociation accumulated at the bottom of the vessel and increased the hydrate dissociation rate there. CT images were obtained during hydrate dissociation to confirm the radial dissociation of the hydrate sample. This radial dissociation process has implications for dissociation of hydrates in pipelines, suggesting lower dissociation times than for longitudinal dissociation. These observations were also confirmed by the numerical simulator predictions, which were in good agreement with the measured thermal data during hydrate dissociation. System pressure and sample temperature measured at the sample center followed the CH{sub 4} hydrate L{sub w}+H+V equilibrium line during hydrate dissociation. The predicted cumulative methane gas production was within 5% of the measured data. Thus, this study validated our simulation approach and assumptions, which include stationary pure methane hydrate-skeleton, equilibrium hydrate-dissociation and heat- and mass-transfer in predicting hydrate dissociation in the absence of sediments. It should be noted that the application of T+H for the pure methane hydrate system (no sediment) is outside the general applicability limits of T+H

Decision aids for localized prostate cancer in diverse minority men: Primary outcome results from a multicenter cancer care delivery trial (Alliance A191402CD)

Background: Decision aids (DAs) can improve knowledge for prostate cancer treatment. However, the relative effects of DAs delivered within the clinical encounter and in more diverse patient populations are unknown. A multicenter cluster randomized controlled trial with a 2×2 factorial design was performed to test the effectiveness of within-visit and previsit DAs for localized prostate cancer, and minority men were oversampled. Methods: The interventions were delivered in urology practices affiliated with the NCI Community Oncology Research Program Alliance Research Base. The primary outcome was prostate cancer knowledge (percent correct on a 12-item measure) assessed immediately after a urology consultation. Results: Four sites administered the previsit DA (39 patients), 4 sites administered the within-visit DA (44 patients), 3 sites administered both previsit and within-visit DAs (25 patients), and 4 sites provided usual care (50 patients). The median percent correct in prostate cancer knowledge, based on the postvisit knowledge assessment after the intervention delivery, was as follows: 75% for the pre+within-visit DA study arm, 67% for the previsit DA only arm, 58% for the within-visit DA only arm, and 58% for the usual-care arm. Neither the previsit DA nor the within-visit DA had a significant impact on patient knowledge of prostate cancer treatments at the prespecified 2.5% significance level (P =.132 and P =.977, respectively). Conclusions: DAs for localized prostate cancer treatment provided at 2 different points in the care continuum in a trial that oversampled minority men did not confer measurable gains in prostate cancer knowledge

Hydrogen storage

The invention relates to the storage of hydrogen. The invention relates especially to storing hydrogen in a clathrate hydrate. The clathrate hydrate according to the present invention originates from a composition, which comprises water and hydrogen, as well as a promotor compound. The promotor compound provides a large reduction of the pressure needed and/or an increase of the temperature needed to form a clathrate hydrate. Also, the desorption of hydrogen gas from the clathrate hydrate is easily obtainable by decreasing the temperature to room temperatureMechanical, Maritime and Materials Engineerin