1,720,964 research outputs found
Invited commentary to 'Effect of resected lung lobe on the prediction of postoperative pulmonary function'
No full textA mathematical model for hybrid-electric propulsion system for regional propeller-driven aircraft
Full text linkTo address the environmental challenges in aviation, this research presents a novel mathematical model for simulating hybrid-electric powerplants in regional propeller-driven aircraft from the early design stages. The model integrates conventional thermal engines with battery and fuel cell systems, supporting up to two independent propulsion lines. Using a throttle-based approach, a linear mathematical formulation estimates power distribution within the architecture. A powerplant management algorithm enhances adaptability to varying power demands while ensuring a physically consistent solution. This approach enables rapid performance evaluation, allowing designers to optimize configurations from the earliest design stages. Case studies validate the model’s effectiveness in meeting diverse power requirements while maintaining a consistent solution. Ultimately, this study provides innovative analytical method for early-stage exploration and optimization of complex propulsion systems, contributing to a more sustainable aviation sector
Sub-lobar lung resection of peripheral T1N0M0 NSCLC does not affect local recurrence rate
No full textDesign proposal and optimization potential for an electric drive motor in a 50 PAX hybrid-electric regional aircraft application
No full textElectric propulsion systems are considered one possibility to reach the ambitious goals of the European Union’s Flightpath 2050 concerning greenhouse gas emissions and noise. This paper proposes an engineering architecture design of an electric motor for a propulsion system in a hybrid-electric regional aircraft. The project partners defined the performance requirements for the thrust of the propulsion system. The electric drive motor for the propellers was calculated and then simulated. The motor is specified in this paper, with the materials possible for construction
Greening Regional Airports: A Vision for Carbon Neutral Infrastructure
No full textThis study provides an overview of the energy demand of a regional airport, divided into individual time horizons. The electrification of aircraft systems raises the question of whether airports will be among the largest electricity consumers in our infrastructure in the future. Sustainability and especially emission reductions are significant challenges for airports that are currently being addressed. The Clean Sky 2 project GENESIS addresses the environmental sustainability of hybrid-electric 50-passenger aircraft systems in a life cycle perspective to support the development of a technology roadmap for the transition to sustainable and competitive electric aircraft systems. This article originates from the GENESIS research and describes various options for ground power supply at a regional airport. Potential solutions for airport infrastructure with a short (2030), medium (2040), and long (2050) time horizon are proposed. In addition to the environmental and conservation benefits, switching from fossil fuels to sustainably produced fuels is also financially attractive for airports, airlines, and travelers. This analysis includes estimating the future energy demand per day, month, and year. In addition, the current flight plan based on conventional aircraft is adapted to the needs of a 50-PAX regional aircraft. The findings confirm that airports will require an enormous amount of electrical energy due to the electrification of air traffi
Efficient Gas Turbine Modeling for Low Emission Aircraft Preliminary Design Workflows
Full text linkA major issue, which has prevented aircraft manufacturers from implementing efficient and cost-effective design processes, is the loose integration of engine models into iterative aircraft design workflows. Modern civil transport aircraft involve several subsystems which are designed, in general, to have the lowest possible weight and the highest possible energy efficiency, so as to minimize their impact on the overall aircraft performance. This same criterion applies to the powerplant system of a modern aircraft, which needs to be specifically designed and built, to meet all the necessary requirements and constraints in terms of performance (thrust and fuel consumption), emissions, noise and costs.
Actually, an effective integration between the design of the aircraft and that of the engines is something which has started to be radically implemented only in recent years.
Traditionally, the design of a new aircraft has always been decoupled from the engine design. Even for supersonic military applications, for which the matching between the two designs represents a crucial aspect, an integrated approach supported by dedicated tools has started to be adopted only from the 1990s. For civil transport aircraft, this radical change in the overall design process has been effectively put into practice only for the latest development programs, such as the ones for the Boeing 787 or the Bombardier C Series (now Airbus A220), during which the engine manufacturers, Rolls-Royce/GE and Pratt & Whitney respectively, have been directly involved in the overall design process of the aircraft since the earliest stages.
Based on these observations, the work described in this thesis addresses the following research question:
How to improve preliminary design workflows focused on the optimization of low-emission aircraft by including detailed effects related to changes to the propulsion system?
In order to enable a radical change, aircraft designers should be supported by dedicated tools, allowing to easily and promptly perform, even at conceptual and preliminary design stages, trade-off studies involving information related to the behaviour of the powerplant system in terms of performance, emissions, dry mass, main dimensions, environmental noise, and costs, by linking these changes to key engine design parameters, such as the overall pressure ratio, the bypass ratio, and the burner exit temperature. This type of approach, from one side, would allow aircraft designers to have, since from early design stages, more precise figures on the powerplant, significantly increasing the number and the quality of information available on the aircraft-engine integration process. On the other side, aircraft designers would be allowed to provide important indications to engine designers on which set of design input variables should grant the matching of aircraft requirements, while minimizing mission fuel burn, emissions, noise, or costs.
The generation of a tool with these characteristics, supporting aircraft preliminary design phases, was the main objective of the collaboration between UNINA and MTU Aero
Engines AG for a three-month internship, involving the author of this thesis and engine design experts from MTU. This work was carried out within the context of the Clean Sky 2 project ADORNO (call H2020-CS2-CFP07-2017-02, project number 821043).
The activities related to the tasks of ADORNO served as proving ground of the capabilities in terms of powerplant system modelling of JPAD, a preliminary aircraft design tool designed at UNINA, in whose development the author of this thesis was directly involved. Observations on the gaps and on the margins for improvement related to the implemented modelling of the powerplant characteristics, that emerged during the execution of the project tasks, motivated even further the need for a new tool accounting specifically for the engine.
For this reason, the first section of this thesis is dedicated to the description of the activities carried out by the author for ADORNO. A second section is dedicated to illustrating the work performed for GENESIS, another Clean Sky 2 project (call H2020-CS2-CFP11-2020-01, project number 101007968), for which the author had the possibility to set up a first version of this new tool for preliminary engine design, specifically dedicated to turboprop engines. A detailed description of the implemented methodology is provided in this section. The last chapter of this thesis is dedicated to a generalization of the previously mentioned methodology for preliminary design to the case of turbofan engines, and to a description of its implementation in JPAD. Finally, several examples of application are provided, for an aircraft similar to the Airbus A320neo
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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