Step-graded AlGaN vs superlattice: Role of strain relief layer in dynamic on-resistance degradation

In this work, we study the impacts of different types of strain relief layer (SRL) on dynamic on-resistance (Ron) degradation of GaN power devices on Si by back-gate ramping and vertical leakage measurement. Our study reveals that the SRL has important effects on the dynamic Ron. Compared with step-graded AlGaN SRL, the superlattice SRL possesses much more energy barriers, which can more effectively block the leakage of holes from GaN buffer and the injection of electrons from Si substrate. Enhancing the carrier blocking ability of SRL could contribute to the suppression of dynamic Ron degradation.

The heat leakage measurement of dewars for infrared detector arrays

Consideration is given to the analysis of a number of implementation of calorimetry method of infrared detector array dewar’s heat leakage measurements. The heat leakage measurements were made both with and without nitrogen vapor heat capacity consideration. The heat exchange process between nitrogen vapor and Dewar’s well walls was analyzed. The most reliable results were achieved by means of approach with calibration.

Interpretable noninterference measurement and its application to processor designs

Noninterference measurement quantifies the secret information that might leak to an adversary from what the adversary can observe and influence about the computation. Static and high-fidelity noninterference measurement has been difficult to scale to complex computations, however. This paper scales a recent framework for noninterference measurement to the open-source RISC-V BOOM core as specified in Verilog, through three key innovations: logically characterizing the core’s execution incrementally, applying specific optimizations between each cycle; permitting information to be declassified, to focus leakage measurement to only secret information that cannot be inferred from the declassified information; and interpreting leakage measurements for the analyst in terms of simple rules that characterize when leakage occurs. Case studies on cache-based side channels generally, and on specific instances including Spectre attacks, show that the resulting toolchain, called DINoMe, effectively scales to this modern processor design.

Quantification of noncircular stent expansion after TAVR into a pathological annulus and its impact on paravalvular leakage

Patients undergoing transcatheter aortic valve replacement (TAVR) may suffer severe clinical complications, caused by paravalvular leakage (PVL) which is defined as leakage between TAVR and aortic annulus. PVL is often facilitated by a severely calcified annulus. This limits the expansion of a self-expandable TAVR stent. To assess TAVR performance in terms of leakage, measurement of regurgitation fraction in a pathophysiological annulus is recommended according to ISO 5840. For this purpose, a configuration of a circular annulus with a calcification nodule has been proposed in the recently published ISO 5840. The impact of the proposed pathophysiological annulus model on the expansion of self-expandable TAVR stents and on the regurgitation fraction was investigated in this study. For this purpose, two commercially available selfexpandable TAVRs (Evolut R and Portico) were implanted in a calcified annulus model. Circular expansion of the TAVR stents was investigated based on μCT scans of the implanted TAVR. The calcification-induced area in which retrograde flow can occur during diastole was detected. These results were then compared with the experimentally determined regurgitation fraction obtained from pulse duplicator tests. The results of the μCT scans showed a continuous leakage area in the region of the annulus for the Evolut R compared to a locally larger leakage area of the Portico, which, however, reattaches to the annulus in the distal inflow region. The hydrodynamic measurements confirmed a smaller leakage in the pathological annulus for the Portico. In summary, it can be assumed that a continuous leakage area in the TAVR stent inflow region encourages the PVL of TAVR.

Antifungal Activities of cis-trans Citral Isomers against Trichophyton rubrum with ERG6 as a Potential Target

Trichophyton rubrum causes ringworm worldwide. Citral (CIT), extracted from Pectis plants, is a monoterpene and naturally composed of geometric isomers neral (cis-citral) and geranial (trans-citral). CIT has promising antifungal activities and ergosterol biosynthesis inhibition effects against several pathogenic fungi. However, no study has focused on neral and geranial against T. rubrum, which hinders the clinical application of CIT. This study aimed to compare antifungal activities of neral and geranial and preliminarily elucidate their ergosterol biosynthesis inhibition mechanism against T. rubrum. Herein, the disc diffusion assays, cellular leakage measurement, flow cytometry, SEM/TEM observation, sterol quantification, and sterol pattern change analyses were employed. The results showed geranial exhibited larger inhibition zones (p < 0.01 or 0.05), higher cellular leakage rates (p < 0.01), increased conidia with damaged membranes (p < 0.01) within 24 h, more distinct shriveled mycelium in SEM, prominent cellular material leakage, membrane damage, and morphological changes in TEM. Furthermore, geranial possessed more promising ergosterol biosynthesis inhibition effects than neral, and both induced the synthesis of 7-Dehydrodesmosterol and Cholesta-5,7,22,24-tetraen-3β-ol, which represented marker sterols when ERG6 was affected. These results suggest geranial is more potent than neral against T. rubrum, and both inhibit ergosterol biosynthesis by affecting ERG6.

Drone-Based Cooling Leakage Measurement from Glass Front Towers

Drones are increasingly gaining more attention these days and they are employed in several applications. At the same time, the steps towards saving energy and improving the efficiency of the buildings are significantly increasing as well. This poster introduces an overall design for a system that will be loaded on a quadcopter to measure the cooling leakage from high-rise buildings in Qatar to meet 2030 vision in environmental development. The proposed design is achieved by using a chip thermal camera to detect the cooling leakage locations. In addition, the drone will need proximity sensors, specifically, Lidar sensor to prevent it from any collision that can happen with the towers. Moreover, a mobile application is built to monitor the tested buildings and the position of the drone.

Large Standoff Magnetometry As a Practical Screening and Monitoring Tool for Pipelines Subjected to Geohazards

Large standoff magnetometry (LSM) as a non-intrusive NDE technology has been used many years in commercial trials for above-ground detection of underground pipeline anomalies associated with stress concentration zones (SCZs). As a passive geo-magnetization flux leakage measurement method, it has been mainly targeting common anomalies such as corrosion, gouges/dents and cracks that are often very localized in small scale. Insufficient consistency and reliability are still the major concern due to technical challenges in getting high resolutions and signal strength at large standoff distance. In comparison, geohazard related external forces induce much large-scale elevated stresses/strains with stronger stress-magnetization signals. Lack of economically viable solutions for pipeline screening and monitoring under geohazard conditions provides a good opportunity to establish LSM’s market position. This work is part of Pacific Gas and Electric Company’s effort in better fundamental understanding of the state-of-the-art LSM technology and its potential to enhance the current industrial practices of pipeline assessment under geohazard conditions. Specifically, 3D mapping of pipelines including depth of cover (DOC) measurement, locating girth welds and peak stresses/strains with risk rating, verification of strain relief operation and continuous monitoring afterwards. Inline inspection (ILI) and geotechnical analysis data together with field excavation and strain-gauge data are utilized as references to cross-check the LSM results. The outcomes indicate geohazard application is very likely a viable application for LSM technology in near future.