Investigation into maximizing component availability for superconducting cables in turbo-electric distributed propulsion aircraft

The commercial aviation industry is growing at a substantial rate, with demand doubling every 15 years and this trend is set to continue well into the 21st Century. At the same time regulatory pressures are being exerted on the industry as governments around the world seek to reduce their greenhouse gas emissions in an effort to contain global temperature rise to 2°C . Combined with existing infrastructure challenges, these issues are forcing air-framers to develop new, novel designs that support sustainable approaches to future aviation to meet environmental, social and economic demands. The pathway to decarbonisation of aviation will involve a combination of fuel, technology and operational measures. Many of the proposed technologies, such as electrical propulsion, are inherently disruptive and require changes to supply-chains,ground operations, maintenance standards and procedures, and pilot training. Such disruption is unavoidable given the scale of the challenge of electrical propulsion: a typical widebody jet engine for passenger aircraft can output over 22 MW fully loaded; an equivalent electrical system must be able to generate, distribute, and produce same amount of thrust with equal or greater reliability than the existing drivetrain that has been perfected over the course of the last century. Turbo-electric Distributed Propulsion (TeDP) is an approach for the electrification of propulsion systems on aircraft that aims to do this. Instead of large turbofan engines used to generate thrust, power in the engines is converted to electricity using electrical generators, and then distributed electrically through a network to propulsion motors placed in aerodynamically advantageous locations, significant fuel savings and performance benefits may be realised. Electrification of the propulsion system comes with large weight penalties. It is critical that the weight of the electrical power system does not mitigate the benefits of electrification. Superconducting electrical machines have been proposed as a route to lightweighting the electrical power system due to their promising high power densities compared to conventional electrical machines. It is proposed that the rest of the electrical power system be superconducting as far as technically possible to minimise heat sinks within the system. Integration of superconducting materials into the most safety critical aspects of commercial aviation raises multiple research questions regarding the design of resilient systems and how appropriate electrical protection strategies can be designed given the strict electric, magnetic, and thermal operating requirements that these components have. All electrical systems experience faults. This Thesis investigates how these faults manifest within a compact, power-electronically interfaced, superconducting network. The research presented in this thesis captures electrical protection requirements through modelling, simulation, and experimentation to develop requirements for TeDP feeder cables. By building on these requirements this thesis will then show how cable design can be optimised to withstand faults and present a control method which enables maximising throughput of cables during temperature rise events. This knowledge aims to improve availability, in terms of reducing the amount of superconducting network de-rating required, and power provision of superconducting feeder cables during adverse conditions encountered by superconducting TeDP aircraft.The commercial aviation industry is growing at a substantial rate, with demand doubling every 15 years and this trend is set to continue well into the 21st Century. At the same time regulatory pressures are being exerted on the industry as governments around the world seek to reduce their greenhouse gas emissions in an effort to contain global temperature rise to 2°C . Combined with existing infrastructure challenges, these issues are forcing air-framers to develop new, novel designs that support sustainable approaches to future aviation to meet environmental, social and economic demands. The pathway to decarbonisation of aviation will involve a combination of fuel, technology and operational measures. Many of the proposed technologies, such as electrical propulsion, are inherently disruptive and require changes to supply-chains,ground operations, maintenance standards and procedures, and pilot training. Such disruption is unavoidable given the scale of the challenge of electrical propulsion: a typical widebody jet engine for passenger aircraft can output over 22 MW fully loaded; an equivalent electrical system must be able to generate, distribute, and produce same amount of thrust with equal or greater reliability than the existing drivetrain that has been perfected over the course of the last century. Turbo-electric Distributed Propulsion (TeDP) is an approach for the electrification of propulsion systems on aircraft that aims to do this. Instead of large turbofan engines used to generate thrust, power in the engines is converted to electricity using electrical generators, and then distributed electrically through a network to propulsion motors placed in aerodynamically advantageous locations, significant fuel savings and performance benefits may be realised. Electrification of the propulsion system comes with large weight penalties. It is critical that the weight of the electrical power system does not mitigate the benefits of electrification. Superconducting electrical machines have been proposed as a route to lightweighting the electrical power system due to their promising high power densities compared to conventional electrical machines. It is proposed that the rest of the electrical power system be superconducting as far as technically possible to minimise heat sinks within the system. Integration of superconducting materials into the most safety critical aspects of commercial aviation raises multiple research questions regarding the design of resilient systems and how appropriate electrical protection strategies can be designed given the strict electric, magnetic, and thermal operating requirements that these components have. All electrical systems experience faults. This Thesis investigates how these faults manifest within a compact, power-electronically interfaced, superconducting network. The research presented in this thesis captures electrical protection requirements through modelling, simulation, and experimentation to develop requirements for TeDP feeder cables. By building on these requirements this thesis will then show how cable design can be optimised to withstand faults and present a control method which enables maximising throughput of cables during temperature rise events. This knowledge aims to improve availability, in terms of reducing the amount of superconducting network de-rating required, and power provision of superconducting feeder cables during adverse conditions encountered by superconducting TeDP aircraft

Gold-NHC complexes in catalysis

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Law-Based Arguments and Messages to Advocate for Later School Start Time Policies in the United States

The increasing scientific evidence that early school start times are harmful to the health and safety of teenagers has generated much recent debate about changing school start times policies for adolescent students. Although efforts to promote and implement such changes have proliferated in the United States in recent years, they have rarely been supported by law-based arguments and messages that leverage the existing legal infrastructure regulating public education and child welfare in the United States. Furthermore, the legal bases to support or resist such changes have not been explored in detail to date. This article provides an overview of how law-based arguments and messages can be constructed and applied to advocate for later school start time policies in U.S. public secondary schools. The legal infrastructure impacting school start time policies in the United States is briefly reviewed, including descriptions of how government regulates education, what legal obligations school officials have concerning their students\u27 welfare, and what laws and public policies currently exist that address adolescent sleep health and safety. On the basis of this legal infrastructure, some hypothetical examples of law-based arguments and messages that could be applied to various types of advocacy activities (e.g., litigation, legislative and administrative advocacy, media and public outreach) to promote later school start times are discussed. Particular consideration is given to hypothetical arguments and messages aimed at emphasizing the consistency of later school start time policies with existing child welfare law and practices, legal responsibilities of school officials and governmental authorities, and societal values and norms

PENGARUH KEPEMIMPINAN TRANSFORMASIONAL DAN QUALITY PRODUCT TRAINING DALAM MENINGKATKAN KINERJA KARYAWAN DENGAN MOTIVASI SEBAGAI VARIABEL INTERVENING (STUDI PADA BANK CENTRAL ASIA KCU GANG TENGAH)

This study aimed to analyze the effect of Transformational Leadership, Training of Product Quality, and Motivation on Employee Performance. The selected research object in this study are employees of BCA KCU Gang Tengah, Semarang. Data were collected through questionnaires filled out independently by 120 respondents selected by random sampling method Proportionate Startified. Measurement of exogenous and endogenous constructs were tested using confirmatory factor analysis, and the results showed that the full feasibility test models are in the range of expected values. The results of this study prove and the conclusions that: (1) Transformational leadership has significant effect on the motivation, (2) Training of Product Quality has significant impact on the motivation, (3) Transformational Leadership significant effect on the performance of employees, (4 ) Training of Product Quality has significant impact on the performance of employees, (5) Motivation has significant impact on the performance of employees, (6) transformational leadership has significant impact on the performance of employees through employee motivation, and (7) Training of Product Quality has significant impact on employee performance through motivation

Diritti sociali e obblighi giuridici

Molti interpreti attribuiscono ai diritti sociali uno status giuridico incerto, fino ad escluderli dal novero dei diritti fondamentali. In particolare, si sostiene che ai diritti sociali non corrispondano adeguate garanzie e che di conseguenza non si possa agire in giudizio per la loro tutela. Questa impostazione trova ulteriori argomenti basati sulla nota tesi della correlatività che, sulla scorta della tipologia di Wesley N. Hohfeld, identifica il contenuto dei diritti con quello dei doveri correlativi. Luigi Ferrajoli aderisce alla tesi della correlatività ma introduce una variazione che dovrebbe permettere di “salvare” i diritti sociali: fra diritti e garanzie (obblighi e divieti correlativi) vi è un nesso non ontico ma deontico; se l’ordinamento non prevede tali garanzie, esse devono venire introdotte, ma ciò non significa che i diritti non esistano. Tuttavia anche Ferrajoli esclude il “cosiddetto” diritto al lavoro – storicamente, il progenitore dei diritti sociali – dalla sua teoria assiomatizzata. Nell’articolo si suggerisce che per “prendere sul serio” i diritti sociali occorre ricostruire una diversa visione dei diritti come nozione non riducibile al correlativo dei doveri, espressione dei processi sociali di rivendicazione

Coordinatively unsaturated ruthenium complexes as efficient alkyne-azide cycloaddition catalysts

The performance of 16-electron ruthenium complexes with the general formula Cp*Ru(L)X (in which L = phosphine or N-heterocyclic carbene ligand; X = Cl or OCH2CF3) was explored in azide−alkyne cycloaddition reactions that afford the 1,2,3- triazole products. The scope of the Cp*Ru(PiPr3)Cl precatalyst was investigated for terminal alkynes leading to new 1,5-disubstituted 1,2,3-triazoles in high yields. Mechanistic studies were conducted and revealed a number of proposed intermediates. Cp*Ru- (PiPr3)(η2-HCCPh)Cl was observed and characterized by 1H, 13C, and 31P NMR at temperatures between 273 and 213 K. A rare example of N,N-κ2-phosphazide complex, Cp*Ru(κ2-iPr3PN3Bn)Cl, was fully characterized, and a single-crystal X-ray diffraction structure was obtained. DFT calculations describe a complete map of the catalytic reactivity with phenylacetylene and/or benzylazide.Publisher PDFPeer reviewe

University of North Dakota Physical Therapy Alumni Preferences for a Transitional Doctorate of Physical Therapy Degree

The purposes of this study are to assess whether University of North Dakota Physical Therapy (UND-PT) graduates desire a transitional Doctorate of Physical Therapy (t-DPT) degree and to determine their preferences regarding this proposed educational program. The survey was sent to 1136 alumni of the UND-PT program spanning from its first graduating class in 1970 to the class of 2002. It consisted of 8 demographic questions and 12 questions regarding areas such as curriculum content, program implementation, and personal views about the Doctorate of Physical Therapy degree. Frequencies for all responses were determined. The respondent data were also analyzed for variation across the demographic groups based on the type of physical therapy degree held, the respondents\u27 American Physical Therapy Association (APT A) membership status, the respondents\u27 primary work position and setting, the number of years of experience, the number of continuing education hours within the past year, and the level of exposure of the DPT degree. Open-ended narrative comments were also analyzed in order to obtain a general idea of alumni\u27s attitudes and feelings toward a t-DPT degree. There were 635 surveys returned for a response rate of 58%. Of these respondents, 67% were female and 32% were male. Eighty-three percent of the respondents are between the ages of 26 and 50. Forty-nine percent held a Master\u27s degree with 9% of respondents earning degrees beyond the MPT level. Fifty-four percent of alumni are currently APTA members. Respondents are employed in 43 of 50 states with a large number (46%) employed in either North Dakota or Minnesota. The majority of alumni are staff physical therapists (62%) working in outpatient/private practice settings (49%) treating mostly the orthopaedic population. Forty percent of respondents are interested in obtaining a t-DPT degree from the University of North Dakota. Respondents indicate online instruction is their preferred mode of delivery (69%). Sixty-one percent of respondents ranked weekend-only classes as their first or second choice. The alumni identify Specialty Physical Therapy, Research/Evidence Based Practice, and Business Management/ Administration as the desired areas of curriculum content. Respondents also indicated family obligations, lack of interest, and time away from work as the potential obstacles preventing them from completing the t-DPT degree. In conjunction with the narrative comments, alumni seem to be unclear about the differences between the t-DPT degree, the advanced clinical doctorate degree, and the clinical specialist certification. The information from this survey will be used by the UND-PT Department to form a t-DPT program which will attempt to correspond with its alumni\u27s needs. Current program content is subject to change and will take into account the results of this scholarly project