Simulation Study of the Use of AlGaN/GaN Ultra-Thin-Barrier HEMTs with Hybrid Gates for Achieving a Wide Threshold Voltage Modulation Range

In this work, novel hybrid gate Ultra-Thin-Barrier HEMTs (HG-UTB HEMTs) featuring a wide modulation range of threshold voltages (VTH) are proposed. The hybrid gate structure consists of a p-GaN gate part and a MIS-gate part. Due to the depletion effect assisted by the p-GaN gate part, the VTH of HG-UTB HEMTs can be significantly increased. By tailoring the hole concentration of the p-GaN gate, the VTH can be flexibly modulated from 1.63 V to 3.84 V. Moreover, the MIS-gate part enables the effective reduction in the electric field (E-field) peak at the drain-side edge of the p-GaN gate, which reduces the potential gate degradation originating from the high E-field in the p-GaN gate. Meanwhile, the HG-UTB HEMTs exhibit a maximum drain current as high as 701 mA/mm and correspond to an on-resistance of 10.1 Ω mm and a breakdown voltage of 610 V. The proposed HG-UTB HEMTs are a potential means to achieve normally off GaN HEMTs with a promising device performance and featuring a flexible VTH modulation range, which is of great interest for versatile power applications.

Monitoring, Predicting, and Optimizing Energy Consumptions

Energy consumption and, consequently, the associated costs (e.g., environmental and monetary) concern most individuals, companies, and institutions. Platforms for the monitoring, predicting, and optimizing energy consumption are an important asset that can contribute to the awareness about the ongoing usage levels, but also to an effective reduction of these levels. A solution is to leave the decisions to smart system, supported for instance in machine learning and optimization algorithms. This chapter involves those aspects and the related fields with emphasis in the prediction of energy consumption to optimize its usage policies.

Measurement and Mitigation of Radon Concentration in a Traditional Dwelling in Galicia, Spain

Radon is a naturally occurring radioactive gas which tends to build up within structures. It is therefore necessary to include techniques to mitigate radon concentration when undertaking refurbishment. The goal of this study is to assess the effectiveness of a mitigation technique based on pressurizing the interior of a building, by testing a prototype of the mitigating device, developed by Siglo 21 Consultores and the LaRUC of the University of Cantabria, under real conditions, to determine its effectiveness during refurbishment. The methodology involved installing the proposed solution in a traditional country dwelling in an area characterized by high radon concentration, on the coast of Galicia, Spain. In order to measure the effectiveness of the solution, continuous measurement sensors, set in an ionization chamber, and properly calibrated by the LaRUC laboratory, were installed. The results obtained show that pressurizing the living quarters brings about an effective reduction in the radon concentration, with a relatively simple building solution. This solution, which is compatible with the principle of minimum intervention, is seen to be especially appropriate when work is undertaken in structures recognized as heritage.

Are Women Less Likely to Ask than Men Partly Because They Work Fewer Hours? A Commentary on Artz et al. (2018)

A long debate in negotiation research concerns the question of whether gender differences in the propensity to initiate negotiations, in behaviors shown during negotiations, and in negotiation performance actually exist. Whereas past negotiation research suggested that women are less likely to initiate negotiations than men, a recent study by Artz et al. (2018) seems to suggest that women are as likely as men to “ask” for higher pay. However, this finding by Artz et al. (2018) was obtained once the number of weekly hours worked was added as a covariate in the statistical analysis. Following extant work, we suggest that the number of weekly hours worked could be—and, from a theoretical stand-point, perhaps should be—considered a mediator of gender differences. Conducting a Monte Carlo analysis based on the results and statistics provided by Artz et al. (2018) also yielded empirical evidence suggesting that weekly hours could be a mediator. Thus, women may be less likely than men to ask for higher pay, among other potential reasons, because they work fewer weekly hours. Based on this alternative conceptualization of the role of weekly hours, our commentary has theoretical implications for the understanding of gender differences in the propensity to initiate negotiations and practical implications for the effective reduction of gender inequalities.

The Use of Natural Sorbents to Reduce Ammonia Emissions from Cattle Faeces

Intensification of animal production leads to an increase in ammonia emissions into the environment. For this reason, various methods and strategies are sought to reduce ammonia emissions from faeces. The aim of the study was to test the possibility of using natural sorbents and sorbent mixtures to reduce ammonia emissions from cattle faeces. Faecal samples for analysis were collected from Holstein-Friesian dairy cows during the winter. The amount of ammonia emissions from cow faeces was determined every seven days, after mixing the faeces with a mixture of selected sorbents. All of the sorbents used have the potential to remove ammonia. The most effective reduction in ammonia was achieved using biochar and a mixture of bentonite with zeolite. The reduction in these groups was 42.56% and 24.56%, respectively, relative to the control group. The results indicate that these sorbents can be used to reduce ammonia emissions from cattle farms.

A Dynamic Technique of Oral Rehabilization Using Fixed Prosthesis and CSC Telescopic Denture for Severe Advanced Periodontitis with Secondary Occlusal Traumatism – A Long-term Case Report

Clinical reports of many literatures had documented that meticulous non-surgical periodontal therapy (NSPT) and combined with periodontal prosthesis application might not only improve periodontal parameters, but also provide effective reduction of microbiological organisms associated with periodontal pathogen. A 54-year old female individual visited with chief complains of gingival bleeding and mobile teeth, and recurrent periodontal abscess over # 13, # 11, # 21, and # 22. Periapical radiographs disclosed moderate periodontal bone loss on the total remained teeth of maxilla and mandible arches. A diagnosis of generalized severe advanced periodontitis (SAP) with secondary occlusal traumatism (SOT) was established. This present case was to document the treatment of a 6 years longitudinally retrospective evaluation of case affected SAP with SOT using treatment of the combination of periodontal and perio-prosthetic design. Results showed that the remarkable improvement of periodontal tissues, reconstruction of posterior bite occlusion and recovery of esthetic appearance. It can be concluded that the Sandwich’s technique in treating patients affected SAP with SOT is an effective and valuable option.

Effective reduction of magnetisation losses in copper-plated multifilament coated conductors using spiral geometry

We wound copper-plated multifilament coated conductors spirally on a round core to decouple filaments electromagnetically under ac transverse magnetic fields and measured their magnetisation losses. Although the coated conductors were plated with copper, which connects all filaments electrically and allows current sharing among them, the spiral geometry decoupled filaments similar to the twist geometry, and the magnetisation loss was reduced effectively by the multifilament structure. The measured magnetisation loss of a 4 mm-wide, 10-filament coated conductor with a 20 μm-thick copper wound spirally on a 3 mm-core was only 7% of that of the same 10-filament coated conductor with a straight shape under an ac transverse magnetic field with an amplitude and frequency of 100 mT and 65.44 Hz, respectively. We separated the measured magnetisation losses into hysteresis and coupling losses and discussed the influence of filament width, copper thickness, and core diameter on both losses. We compared the hysteresis losses with the analytical values given by Brandt and Indenbom and compared the coupling losses with the values calculated using a general expression of coupling loss with the coupling time constants and geometry factors.

TEM in toroidal plasmas with anisotropic electron temperature

Trapped electron modes (TEMs) in tokamak plasmas with anisotropies of electron temperature and its gradient are studied by solving the gyrokinetic integral eigenmode equation. Detailed numerical analyses indicate that, in comparison with that in plasmas of isotropic electron temperature, TEMs are enhanced (weakened) by the anisotropy with temperature in the direction perpendicular to magnetic field higher (lower) than that in the direction parallel to the magnetic field when the latter is kept constant. However, the enhancement is limited such that TEMs are weakened rapidly and even stabilized when the anisotropy is higher than a critic value owing to an effective reduction of bounce movement of the trapped electrons. In addition, it is found that the gradients of perpendicular and parallel temperatures of electrons have driving and suppressing effects on the TEMs, respectively. The overall effects of the temperature gradients of electrons and ions, magnetic shear, safety factor, density gradient on TEMs in the presence of the anisotropies are presented in detail.