1,720,990 research outputs found
Systemic design for sustainable territorial development: ecosystem definition to support autopoietic local economies
Full text linkTo meet the current challenges to fight global and interconnected problems as waste production, systemic thinking is needed to provide a new cultural paradigm to create Sustainable, Circular and Blue Economies. One action can be done spotlighting the local territory in which we are living every day enhancing cultural and natural resources, indeed of considering it as a place where the products are manufactured, travel everywhere and leave only waste. Systemic Design can
provide an answer creating eco-innovation and environmental, social and economic sustainability, especially at the local level. A multiple case-study analysis on previous projects on Systemic Design has conducted to understand the principal barriers in their implementation and their outcomes to reach sustainable territorial development. After the identification of the new opportunities created at the entrepreneurial level, finally, it is designing the entrepreneurial ecosystem of innovation to foster Systemic sustainable projects framed in a specific context of referenc
Design of an ecosystem to foster systemic eco-innovation. Systemic design for autopoietic local economies
Full text linkThe current global environmental situation, with its interconnected problems, requires holistic approaches to provide a cultural paradigm shift and a different economy to overcome the linear one. Systemic Design (SD) can represent a solution creating opportunities for eco- and system innovation, especially in the manufacturing sector, which will soon face a revolution in the production model. Thus, SD can help achieve environmental and economic sustainability at the local level. A multiple case study analysis on SD projects was developed to understand the significant eco-entrepreneurial opportunities that have emerged and the barriers for their
implementation. Finally, an ecosystem is designed to foster systemic innovation based on helix innovation models and identify the facilitator for its creation, namely, the ‘local systemic network booster’
Injection and combustion modelling in hydrogen internal combustion engines
No full textThis thesis focuses on the numerical analysis of the injection, mixing, and combustion
in direct injection internal combustion engines fueled by hydrogen.
Most likely, the current transition towards a sustainable mobility will be achieved only
through a combination of different technologies. For specific applications, such as heavyduty
road transport, hydrogen-powered internal combustion engines—particularly those
based on direct injection — represent a competitive powertrain solution in terms of cost
and reliability compared to more innovative alternatives like fuel cells.
Although internal combustion engines have been in use for over a century, the unique
chemical and physical properties of hydrogen necessitate a renewed analysis of the fundamental
processes governing engine operation, such as injection, fuel-air mixing, and
combustion.
For this reason, the first step of this thesis is the characterization of the fluid dynamics
of high-pressure hydrogen direct injection into the combustion chamber. The study analyzes
the fluid-dynamic structures characterizing these flows, with particular attention
to the numerical setup required to accurately resolve them. With respect to the state of
art, the analysis focuses on the effect of the typical combustion chamber conditions on
the jet phenomenology. More specifically, an analysis is proposed by varying the cylinder
pressure over time to determine the possible presence of dynamic phenomena that
could alter the flow configuration compared to what is observed under constant pressure
ratios.
As a second step, focus has been posed on the influence of the injector exit section geometry,
to determine whether specific configurations are more suitable for use in internal
combustion engines. Although the injector outlet sections are primarily circular or annular,
new geometries (triangular, star-shaped, rectangular, and elliptical) have been
studied to understand their effect on the mixing between the jet and the surrounding
environment. While some of these geometric configurations have already been analyzed
in the aerospace field, their applicability in the automotive sector has been tested in
this thesis work. Significant differences have been observed in the shock and expansion
system characterizing these flows, for which a detailed explanation has been provided.
Subsequently, the analysis has been extended to the design space of key variables affecting
the mixing process, such as the injection pressure, timing, and nozzle geometry.
The goal has been to extend the engine operability under increasingly lean mixtures
compared to the current state of the art. More specifically, focus has been placed on
mixtures featured by an equivalence ratio of 0.25, which help to reduce wall heat losses
while limiting nitrogen oxide emissions. It has been demonstrated that the mixture
stratification under these conditions is the key to increasing the combustion process
speed. In particular, multi-injection strategies have been tested, showing the potential
to optimize the combustion speed and NOx emissions.
Finally, in an effort to improve internal combustion engine modeling, a procedure has
been developed to account for the effects of thermodiffusive instabilities in hydrogen
flames within the framework of the G-equation combustion model. Preliminary results
show the potential to effectively capture pressure trends with a single preliminary calibration
process regarding the interaction between the flame front and the in-cylinder
turbulence
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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