Educational Audiology: Hearing and Speech Management

Non

Automatically Pausing Caller Video When the Caller’s Face is Out-of-frame

Many video communication applications offer a picture-in-picture mode that shows the caller’s video feed that usually includes the caller’s face in addition to that of others that participate in the call. The impulse to check one’s own image as provided in the user interface can distract callers from focusing on the other participants. Further, if the caller moves, the camera may capture and provide a video feed that includes unexpected content, e.g., the room background. This disclosure describes the use of face detection at the caller end of a video call that ensures that the caller’s camera feed includes a face and automatically switches to a static picture being displayed to the call recipient if the face is not detected. At the caller end, the caller\u27s video feed is not displayed if the face is present. In this manner, the described techniques simultaneously safeguard against inadvertent display of other content while removing the distraction of one\u27s own face from the user

Investigation of HTS cable impact on turboelectric aircraft performance

With significant interest in the use of high-temperature superconducting (HTS) components in electric aircraft, there is a need for novel modelling techniques that allow architecture-level studies of the electrical systems including HTS components. In this study, a simple electric network architecture, as proposed in the literature has been considered, which includes generators, dynamic propulsion load and cables. This electric network has been modelled considering conventional technology and using HTS cables by replacing the conventional copper cables, to evaluate the variations in the network performance. The network performance has been studied for the dynamically varying propulsion load, which is nearly equivalent to the aircraft load over the entire flight duration. Following this, electric faults have been applied at various locations, and the impact of HTS cables on the network fault levels has been evaluated. The fault current levels are compared using both conventional and HTS cables, due to the fault current limiting properties of the HTS cables, they are observed to offer lowered fault current values

Collagen Deposition During Wound Repair

Collagen fiber diameters, amount of birefringent collagen (brightness) and birefringence retardation were measured in implanted collagen-based sponges containing hyaluronic acid (HA) and fibronectin (FN). In the presence of HA and FN, increased number of fibroblasts and brightness were observed 6 days after wounding. Increased brightness in the presence of HA and FN reflected increased deposition of oriented collagen fibers. From days 9 to 12, increased fiber diameters were similar in implanted collagen-based sponges with or without HA and FN. Increased birefringence retardation in sponges containing HA and FN was consistent with increased packing density of collagen fibers observed by scanning electron microscopy. Our results suggest that HA and FN are effective in promoting fibroblast movement into a collagen sponge and deposition of collagen fibers during the early phases of wound healing. Use of a collagen-based sponge containing HA and FN may enhance collagen deposition in situations where healing is compromised as in the case of dermal ulcers

Simulation Models for Superconducting Components of the Electric Aircraft

In recent decades, a growing focus has been on reducing fossil fuel consumption and minimizing CO2 emissions in the transportation sector. The aerospace industry, which accounted for more than 2% of global carbon emissions in 2021, has taken measures to address this issue. One promising solution to achieve this objective is the development of fully electric aircraft (FEA). In this regard, superconducting technology offers promising advantages, including compactness, lightweight, and higher efficiency to speed up this transition. This work considers a superconducting propulsion system for an electric aircraft. Among the components, the modeling of resistive superconducting fault current limiter (RSFCL) and superconducting DC cable are studied. These models are simulated by MATLAB programming and SIMULINK, and the results are shown. The models analyze their electrical-thermal behavior in a short short-circuit and in normal operation conditions. Finally, a SIMULINK model containing the fault limiter and cable is simulated, and the results are presented. As a result, different models are compared and suitable designs are presented for both applications

Modeling Superconducting Components of the Electric Aircraft

Electrification of the mobility sector is at the center of attention to reduce CO2 emissions and mitigate man-made climate change. At present, aircraft is responsible for around 2.4 % of the annual global carbon emissions. This is a motivation behind developing fully-electric, zero-emission aircraft. The advantages of superconductivity including compactness, lightweight, and high efficiency make this technology a promising choice to accelerate the transition to electric aircraft. The powertrain for a large electric aircraft includes different components like motors, converters, DC and AC cables, batteries, fuel cells, fault current limiters, power generators and fuel storage. The higher the total power of the electric aircraft, the more interesting it is to use superconducting devices. In this work, the approach to model the overall electric powertrain with MATLAB/SIMULINK is presented. Within the overall model, several superconducting devices are simulated in detail. One component is a resistive superconducting fault current limiter which is modeled via an electrical-thermal lumped-parameter method in MATLAB. The simulation results are given in detail and discussed. In addition, a configurable MATLAB Simulink model of the fault limiter is developed for integration with wider systems models. Another model for a superconducting DC cable has been developed. The electrical-thermal, lumped parameter and two-dimensional modeling of this component are studied and its operation is simulated using MATLAB programming. Finally, the overall simulation methodology is presented and the current status is given

Fibroblast and Epidermal Cell-Type I Collagen Interactions: Cell Culture and Human Studies

Fibroblast and epidermal cell-type I collagen sponge interactions were studied in cell culture as well as in humans. In cell culture, fibroblasts were observed to migrate and proliferate throughout a type I collagen sponge containing either hyaluronic acid (HA) or fibronectin (FN). Fibroblasts accumulated in the center of the pores in sponges containing HA and appeared to surround themselves with newly synthesized extracellular matrix. In sponges containing FN, fibroblasts attached to and elongated along the collagen fibers of the sponge. In the absence of FN or HA protein synthesis of fibroblasts appeared to be inhibited by the presence of the type I collagen sponge. Epidermal cells grown on plastic or on type I collagen, formed sheets. Epidermal cells grown on a collagen sponge morphologically appeared different than cells grown on plastic. The type I collagen matrix studied in cell culture was applied to dermal wounds of patients with pressure ulcers in order to evaluate its effect on dermal wound healing. The areas of ulcers treated for 6 weeks with a type I collagen sponge decreased by about 40% compared with no change in the areas of untreated controls. Preliminary results suggest that a type I collagen sponge is a biocornpatible substrate with fibroblasts and epidermal cells and may be effective in enhancing healing of chronic skin ulcers

Pole-to-Pole Fault Management for Electric Aircraft DC Network with HTS Cables

Full-electric propulsion aircraft is attracting a lot of interests in recent years. To improve the power density of electric propulsion systems, superconducting power devices are attractive due to their high current density and high efficiency. Fault analysis and fault management techniques with the combination of superconducting power devices are critically needed to ensure the safety and reliability of electric propulsion systems. In this paper, pole-to-pole fault analysis is carried out for the DC network in electric aircraft. High temperature superconducting (HTS) cable modeling is taken into consideration for the fault characterization. A system-level pole-to-pole fault management strategy is proposed to detect and isolate the faults at different locations. The analytical results are verified by the simulation models using Matlab/Simscape. The studies in this paper provide valuable guidance for the design and setting of protection systems in electric aircraft

DC line to line short-circuit fault management in a turbo-electric aircraft propulsion system using superconducting devices

Electric aircraft has already become a reality, with demonstration flights at power ratings of less than 1 MVA. Conventional machines and distribution technologies suffer from poor power densities when scaling to large power demands, leading to significant challenges in applying this technology from small (100-seater) planes. Superconducting devices could be an enabler for electric aviation due to their great potential for high efficiency and low weight. However, while the development of the superconducting components presents a significant challenge, the safe and effective combination of such components into a propulsion system also requires a significant area of research. For this purpose, a signal-based MATLAB-Simscape model for a dc network architecture in a turbo-electric aircraft has been established and the highly nonlinear models for the superconducting devices have been developed and integrated. This network model has been used to understand the fault current magnitude and rise time, as well as the stability behavior of the system utilizing the realistic electro-thermal models of superconducting devices in it. The derived network was investigated for a bus bar short circuit fault using both superconducting fault current limiter and fault current limiting high temperature superconducting (FCL HTS) cable. Based on the network characteristics, a fault tolerant dc network design was achieved by utilizing the FCL HTS cables. Similarly, the operation limits of the protection devices have been reduced greatly using superconducting components