scholarly journals Commercial Aircraft Electrification—Current State and Future Scope

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8381
Author(s):  
Liya Tom ◽  
Muhammad Khowja ◽  
Gaurang Vakil ◽  
Chris Gerada
Keyword(s):  
Fault Tolerant ◽  
Cooling System ◽  
High Strength ◽  
Hydraulic Systems ◽  
Commercial Aircraft ◽  
Future Design ◽  
Current State ◽  
Electric Aircraft ◽  
Increasing Demand ◽  
Drive Systems

Electric and hybrid-electric aircraft propulsion are rapidly revolutionising mobility technologies. Air travel has become a major focus point with respect to reducing greenhouse gas emissions. The electrification of aircraft components can bring several benefits such as reduced mass, environmental impact, fuel consumption, increased reliability and quicker failure resolution. Propulsion, actuation and power generation are the three key areas of focus in more electric aircraft technologies, due to the increasing demand for power-dense, efficient and fault-tolerant flight components. The necessity of having environmentally friendly aircraft systems has promoted the aerospace industry to use electrically powered drive systems, rather than the conventional mechanical, pneumatic or hydraulic systems. In this context, this paper reviews the current state of art and future advances in more electric technologies, in conjunction with a number of industrially relevant discussions. In this study, a permanent magnet motor was identified as the most efficient machine for aircraft subsystems. It is found to be 78% and 60% more power dense than switch-reluctant and induction machines. Several development methods to close the gap between existing and future design were also analysed, including the embedded cooling system, high-thermal-conductivity insulation materials, thin-gauge and high-strength electrical steel and integrated motor drive topology.

MECASTEEL 145

Alloy Digest ◽  
2014 ◽  
Vol 63 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Yield Strength ◽  
Tensile Properties ◽  
High Strength ◽  
Hydraulic Systems ◽  
Minimum Yield

Abstract Mecasteel 145 (minimum yield strength 145 ksi) is a high-strength prehardened steel that can be used in substitution for conventional steels, such as AISI 4330, in the manufacture of massive steel components such as machines, hydraulic systems, and pumps. This datasheet provides information on composition and tensile properties as well as fracture toughness. It also includes information on forming. Filing Code: SA-691. Producer or source: Industeel USA, LLC. Revised as Alloy Digest SA-703, July 2014.

MECASTEEL 90

Alloy Digest ◽  
2014 ◽  
Vol 63 (3) ◽  
Keyword(s):  
Fracture Toughness ◽  
Yield Strength ◽  
Physical Properties ◽  
Tensile Properties ◽  
High Strength ◽  
Hydraulic Systems ◽  
Aisi 4130 ◽  
Minimum Yield

Abstract Mecasteel 90 (minimum yield strength 90 ksi) is a high-strength prehardened steel that can be used in substitution for conventional steels, such as AISI 4130, in the manufacture of massive steel components such as machines, hydraulic systems, and pumps. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as fracture toughness. It also includes information on forming and joining. Filing Code: SA-697. Producer or source: Industeel USA, LLC.

Superalloy Cooling System for the Composite Rim of an Inside-Out Ceramic Turbine

2017 ◽  
Author(s):  
N. Courtois ◽  
F. Ebacher ◽  
P. K. Dubois ◽  
N. Kochrad ◽  
C. Landry ◽  
...  
Keyword(s):  
Gas Turbines ◽  
Cooling System ◽  
High Strength ◽  
Carbon Composite ◽  
Flow Rate Ratio ◽  
Small Scale ◽  
Inlet Temperature ◽  
Operating Temperatures ◽  
Critical Components ◽  
Inside Out

The use of ceramics in gas turbines potentially allows for very high cycle efficiency and power density, by increasing operating temperatures. This is especially relevant for sub-megawatt gas turbines, where the integration of complex blade cooling greatly affects machine capital cost. However, ceramics are brittle and prone to fragile, catastrophic failure, making their current use limited to static and low-stress parts. Using the inside-out ceramic turbine (ICT) configuration solves this issue by converting the centrifugal blade loading to compressive stress, by using an external high-strength carbon-polymer composite rim. This paper presents a superalloy cooling system designed to protect the composite rim and allow it to withstand operating temperatures up to 1600 K. The cooling system was designed using one-dimensional (1D) models, developed to predict flow conditions as well as the temperatures of its critical components. These models were subsequently supported with computational fluid dynamics and used to conduct a power scalability study on a single stage ICT. Results suggest that the ICT configuration should achieve a turbine inlet temperature (TIT) of 1600 K with a composite rim cooling-to-main mass flow rate ratio under 5.2% for power levels above 350 kW. A proof of concept was performed by experimental validation of a small-scale 15 kW prototype, using a commercially available bismaleimide-carbon (BMI-carbon) composite rim and Inconel® 718 nickel-based alloy. The combination of numerical and experimental results show that the ICT can operate at a TIT of 1100 K without damage to the composite rim.

scholarly journals Attitude toward second opinions in Germany – a survey of the general population

2022 ◽  
Vol 22 (1) ◽  
Author(s):  
Nadja Könsgen ◽  
Barbara Prediger ◽  
Anna Schlimbach ◽  
Ana-Mihaela Bora ◽  
Simone Hess ◽  
...  
Keyword(s):  
Knee Pain ◽  
Treatment Recommendation ◽  
Federal States ◽  
Future Design ◽  
Online Portal ◽  
Current State ◽  
Stratified Sample ◽  
Survey Results ◽  
Informed Treatment ◽  
State Of Research

Abstract Background Second medical opinions (SOs) can assist patients in making informed treatment decisions and improve the understanding of their diagnosis. In Germany, there are different approaches to obtain a structured SO procedure: SO programs by health insurers and SOs according to the SO Directive. Through a direct survey of the population, we aimed to assess how structured SOs should be provided to fulfil patients’ needs. Methods A stratified sample of 9990 adults (≥18 years) living in the federal states of Berlin and Brandenburg (Germany) were initially contacted by post in April and sent a reminder in May 2020. The survey results were analyzed descriptively. Results Among 1349 participants (response rate 14%), 56% were female and the median age was 58 years (interquartile range (IQR) 44–69). Participants wanted to be informed directly and personally about the possibility of obtaining an SO (89%; 1201/1349). They preferred to be informed by their physician (93%; 1249/1349). A majority of participants would consider it important to obtain an SO for oncological indications (78%; 1049/1349). Only a subset of the participants would seek an SO via their health insurer or via an online portal (43%; 577/1349 and 16%; 221/1349). A personally delivered SO was the preferred route of SO delivery, as 97% (1305/1349) would (tend to) consider this way of obtaining an SO. Participants were asked to imagine having moderate knee pain for years, resulting in a treatment recommendation for knee joint replacement. They were requested to rate potential qualification criteria for a physician providing the SO. The criteria rated to be most important were experience with the recommended diagnosis/treatment (criterion (very) important for 93%; 1257/1349) and knowledge of the current state of research (criterion (very) important for 86%; 1158/1349). Participants were willing to travel 60 min (median; IQR 60–120) and wait 4 weeks (median; IQR 2–4) for their SO in the hypothetical case of knee pain. Conclusion In general, SOs were viewed positively. We found that participants have clear preferences regarding SOs. We propose that these preferences should be taken into account in the future design and development of SO programs.

scholarly journals From Rise to Fall

Politeja ◽  
2019 ◽  
Vol 16 (5(62)) ◽  
pp. 175-192
Author(s):  
Leontiy Georgievich Byzov
Keyword(s):  
Public Opinion ◽  
Comparative Studies ◽  
Social Groups ◽  
Public Opinion Research ◽  
Strong State ◽  
Current State ◽  
Increasing Demand ◽  
Academy Of Sciences ◽  
Value Crisis ◽  
Current Stage

Based on the 2000–2018 comparative studies of the Institute of Sociology of the Russian Academy of Sciences and the Russian Public Opinion Research Center (VTsIOM), the author presents the process of transition of the “Putin era” from the stage of consolidation built upon public consensus achieved at the beginningof the “zero” (нулевых) years to the current stage of value crisis that arose in 2012–14 and lasts to this day. Although the current state of society canno tbe unequivocally interpreted as a split, contradictions in the system of values are growing. Implementation of the idea of a strong state is delegated to social groups that are least modernized. Moreover, within the state itself, frustration has been growing among the whole society. The increasing demand for change has not yet been materialized in the form of any political “body”, which makes the inevitable transit of epochs extremely risky for the country and the society.

Integrated Strategy for Commercial Aircraft Fault-Tolerant Control

2018 ◽  
Vol 41 (6) ◽  
pp. 1423-1434 ◽  
Author(s):  
Yishi Liu ◽  
Zhang Ren ◽  
Jonathan E. Cooper
Keyword(s):  
Fault Tolerant ◽  
Fault Tolerant Control ◽  
Commercial Aircraft ◽  
Integrated Strategy

Resilient and Timely Event Dissemination in Publish/Subscribe Middleware

2012 ◽  
pp. 1-20
Author(s):  
Christian Esposito ◽  
Domenico Cotroneo
Keyword(s):  
Fault Tolerant ◽  
Multicast Tree ◽  
Temporal Constraints ◽  
Multicast Protocol ◽  
Message Dissemination ◽  
Increasing Demand ◽  
To Receive

Recently we have witnessed an increasing demand of fault-tolerant communications in publish/subscribe middleware. Although several reliable solutions have been proposed, none of them address the problem of achieving a resilient and timely event dissemination. We investigate how guaranteeing assured message dissemination despite occurrence of network faults without breaking temporal constraints. The contribution of this article is on devising a FEC approach where encoding functionality is placed at the root and on a subset of interior nodes in the multicast tree. Simulations-based experiments demonstrate that the proposed approach allows all the interested subscribers to receive all the published messages and the adopted resiliency mean does not affect the performance of the multicast protocol.

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