37,746 research outputs found
Aircraft turning ground maneuvers
In this project a fully parameterized mathematical model of an aircraft turning on the ground in order to get the maximum aircraft speed and minimum infrastructure taxiway radius for three different types of aircrafts (A320, A380 and B737) is developed.
The mathematical model takes the form of a system of coupled ordinary differential equations (ODEs). The airframe is considered as a rigid body with six DOF and the equations of motion are derived by balancing the respective forces and moments. Other formulas as Newtonâs second law, centripetal equations, friction formulas and other equations will be used to calculate the safest velocity depending on the radius of the taxiway curvature.
The software Matlab will be used so as to make all the calculations and will enable us to change the parameters such as mass, friction or radius to find new velocities according to the aircraft. Moreover, the use of Microsoft Excel software to insert those results already found in Matlab and create new tables depending on the radius and ground weather conditions (dry or wet). The results show that each aircraft has a different safety velocity although they turn with the same taxiway radius.
There is also a bibliographic and modelling work explaining how to get all the equations and the different types of taxiway entries
Deformation and tension analysis during embryonic development
The aim of this document is to introduce the reader into the process, through microscopic threedimensional
images, of the cellular embryonic deformation of the Drosphila Melanogaster fly through
its development. It will also be exposed a program with which it will be possible to calculate the
tensions through a code of finite elements from a model of lineal material.
In order to carry this study, it will be used the Matlab program, with which a code will be created where
the experimental data will be entered and the tension and the deformation of the affected cells will be
calculated. The study will be carried through two models: one of them will be a cell-centered model
while the other one will be a vertex model.
With the pertinent procedures, it will be obtained a series of documents that, when analyzed with a
tridimensional visualization tool, will offer a representation of both models and the evolution for each
of their meshes. This project will conclude with an appreciation on the efficiency of both
two-dimensional and three-dimensional approaches
Theoretical calculations for precision polarimetry based on Mott scattering
Electron polarimeters based on Mott scattering are extensively used in
different fields in physics such as atomic, nuclear or particle physics. This
is because spin-dependent measurements gives additional information on the
physical processes under study. The main quantity that needs to be understood
in very much detail, both experimentally and theoretically, is the
spin-polarization function, so called analyzing power or Sherman function. A
detailed theoretical analysis on all the contributions to the effective
interaction potential that are relevant at the typical electron beam energies
and angles commonly used in the calibration of the experimental apparatus is
presented. The main contribution leading the theoretical error on the Sherman
function is found to correspond to radiative corrections that have been
qualitatively estimated to be below the 0.5% for the considered kinematical
conditions: unpolarized electron beams of few MeV elastically scattered from a
gold and silver targets at backward angles.Comment: Accepted versio
The exercise of moral imagination in stigmatized work groups.
This study introduces the concept of moral imagination in a work context to provide an ethical approach to the controversial relationships between dirty work and dirty workers. Moral imagination is assessed as an essential faculty to overcome the stigma associated with dirty work and facilitate the daily work lives of workers. The exercise of moral imagination helps dirty workers to face the moral conflicts inherent in their tasks and to build a personal stance toward their occupation. Finally, we argue that organizations with dirty work groups should actively adopt measures to encourage their employeesâ exercise of moral imagination. This study investigates how organizations might create conditions that inspire moral imagination, particularly with regard to the importance of organizational culture as a means to enhance workersâ moral sensitivity. Furthermore, this investigation analyzes different company practices that may derive from a culture committed to moral imagination.Moral imagination; Dirty work; Moral conflicts; Stigma; Work groups;
Subjective Well-Being: Easterlin Paradox, the (decreasing) Return(s)? From log to square, new evidence from wealthier data
The quest for happiness is neither new for human beings, nor for economists. With the systematization of household surveys, Subjective Well-Being studies have flourished. Discussions now focus on the slope of the virtually unchallenged curvilinear functional form between income and life satisfaction. Indeed, if growth positive returns are not -yet- contested for societies that have difficulties satisfying their population?s basic needs, the correlation between income and Subjective Well-Being in wealthier countries has no consensus; from flat to steep, researchers dither? Benefitting from larger datasets, recent papers have attempted to debunk the Easterlin paradox. They show that self-reported well-being is steadily and positively correlated with income and growth, even in developed countries. However, using the most up-to-date global surveys, calculations cast doubt upon the belief in an eternal sunshine relation between income and ?happiness?. Indeed, we observe that the curvilinear relation between income and happiness could be challenged by the quadratic one. Thus, it now appears difficult to reject the possibility of decreasing returns, to the extent that it might be possible to consider, not only a weak, but a negative correlation between income and happiness for wealthier countries. Nevertheless, this perspective is likely dependent on the sample size. Moreover, we claim no direct causality for the uncovered negative slope. Further investigations would be necessary to prove, inform - or disprove - these new findings. La recherche du bonheur n?est pas une quĂȘte nouvelle pour les humains, ni pour les Ă©conomistes ! Avec la systĂ©matisation des enquĂȘtes mĂ©nages, les Ă©tudes sur le bien-ĂȘtre subjectif se sont multipliĂ©es. Si le caractĂšre curvilinĂ©aire de l?association entre revenu et bien-ĂȘtre subjectif n?est pas, jusqu?ici, remise en question, les dĂ©bats se sont rĂ©cemment concentrĂ©s sur la pente de celle-ci. En effet, bien que l?impact positif de la croissance sur le bien-ĂȘtre dans les pays en dĂ©veloppement ne soit pas contestĂ©, pour les pays industrialisĂ©s, la corrĂ©lation entre bien-ĂȘtre subjectif et revenu est loin de faire l?objet d?un consensus. RĂ©cemment, en utilisant des bases de donnĂ©es de plus en plus larges, certaines recherches ont remis en cause le paradoxe d?Easterlin. D?aprĂšs ces travaux, il serait dĂ©sormais clair que le bien-ĂȘtre subjectif soit durablement et positivement corrĂ©lĂ© avec le revenu et la croissance, mĂȘme pour les pays industrialisĂ©s. NĂ©anmoins, nos observations rĂ©alisĂ©es grĂące aux plus complĂštes bases de donnĂ©es actuellement disponibles, montrent que la relation idyllique entre revenu et bien-ĂȘtre subjectif peut ĂȘtre remise en question. La forme curvilinĂ©aire pourrait en effet, cacher une forme quadratique. Il deviendrait alors difficile de rejeter l?existence de gains marginaux dĂ©croissants. NĂ©anmoins, il serait imprudent d?Ă©tablir un lien de causalitĂ© pour la partie dĂ©croissante de la pente ainsi mise Ă jour. De nouvelles recherches et des donnĂ©es plus longues seront nĂ©cessaires pour alimenter, ou rĂ©futer, nos observations. (Full text in english)
Assessing Corruption: Expert Surveys versus Household Surveys, Filling the Gap
La mesure de la gouvernance est une source dâoccupation relativement nouvelle pour les Ă©conomistes. Le World Bank Institute a ouvert la voie Ă la fin des annĂ©es 90 avec la dĂ©sormais cĂ©lĂšbre suite âGovernance Mattersâ, I, II, III, IV⊠Le peu dâimagination de KKZ1 dans le choix du titre de leurs publications cache, en rĂ©alitĂ©, les plus populaires des indicateurs de gouvernance. Lâaccent mis sur la corruption pourrait, lui aussi, revendiquer la paternitĂ© de la Banque mondiale dans la mesure oĂč lâon doit la crĂ©ation de Transparency International Ă Peter Eigen ancien cadre de la Banque, mais Ă©galement, Ă James Wolfensohn, premier directeur de la Banque Ă sâintĂ©resser au flĂ©au de la corruption, dans un contexte de « de-gĂ©opolitisation » de lâaide au dĂ©veloppement. Avec les prĂ©mices de la systĂ©matisation des enquĂȘtes mĂ©nages, une nouvelle maniĂšre de mesurer la gouvernance voit le jour. Si les enquĂȘtes menĂ©es auprĂšs de la population peuvent constituer un outil intĂ©ressant pour Ă©valuer la qualitĂ© des institutions, cette prise en compte de lâopinion des populations introduit de nouveaux Ă©cueils. Cette Ă©tude vise Ă analyser lâĂ©cart de perception entre experts et populations, en matiĂšre de corruption. En effet, les enquĂȘtes dâexperts et les enquĂȘtes mĂ©nages sâaccordent difficilement dans leurs estimations de lâĂ©tendue de la corruption. Nous suggĂ©rons que la libertĂ© de la presse, la culture, la tolĂ©rance et la confiance envers les dirigeants puissent venir fausser les pistes. Governance measurement is a relatively new source of entertainment for economists. The World Bank Institute paved the way in the late 90`s with the now famous suite âGovernance Mattersâ, I, II, III, IV⊠The little imagination of KKZ, regarding the choice of their publications title, hides the most popular aggregated governance indicators. Corruption focus could also claim World Bank parenthood since Transparency International birth was the fruit of a former âaffairâ between James Wolfensohn and Peter Eigen. With the prelude to household surveys systematization, a new way to measure governance and corruption saw the day. If household surveys may stand for an interesting tool for institutional assessment, populationsâ opinions also introduce new pitfalls. This study aims to investigate the gap between expert and household surveys regarding corruption measurement. Indeed, experts and populations barely agree on their estimations of corruption extent. We suggest that press freedom, culture, permissiveness and leadership approval may cover oneâs track.(Full text in french)
Development stakeholders and territorial identity in Portugal
The need to reaffirm the diversity of places and regions in order to make them economically and culturally âmore competitiveâ on the globalised market of goods and services has been widely accepted in regional and local development policies in Portugal, but much more so rhetorically than in operational terms. This largely reflects the fact that policies, as well as their instruments, do not rely on empirical evidence of the changing character of territorial identity. In particular, there are virtually no records regarding representations of territorial identity features and issues by local/regional development stakeholders, both individual and institutional ones. The problem is that appropriate conceptualisations and analytical tools for comprehensive identification and assessing of various dimensions local/regional identity have been lacking. Since it has not been clear what the identity of places and regions means in factual and verifiable terms to different development stakeholders, it is has not been possible to determine what aspects of the identity need to be strengthened, preserved, diversified, or made âmore competitiveâ in regional and local development policy design and implementation. This paper brings forward a methodological framework for the study of the changing character of local identities and the role of local development stakeholders in this change. The region-specific evidence obtained from a nation-wide field survey of Portuguese local development agentsâ knowledge, attitudes and practice in relation to the territorial identity as a regional development issue is presented and discussed.
Measuring corruption: perception surveys or victimization surveys? Towards a better comprehension of populationsâ perception mechanisms: press freedom, confidence and gossip
While methodologies and survey techniques recorded progress over the years, corruption measurement remains a many-headed monster. Since 2003 and the first publication of Transparency Internationalâs Global Corruption Barometer, researchers have access to populationâs feeling about the corruption scourge across institutions. Thereby, wider room emerged for populationsâ perceptions in the field of corruption quantification. In this paper, we analyze the gulf separating perceived corruption from experienced bribe situations using global household surveys in a Panel dataset. We show that the gap between these two types of data can be wide and unevenly distributed across countries. Introducing further objective and subjective data we try to puzzle out perception mechanisms. Bien que les techniques dâenquĂȘte et les mĂ©thodologies se soient amĂ©liorĂ©es au fil des annĂ©es, la mesure corruption demeure problĂ©matique. Depuis 2003 et la premiĂšre publication du BaromĂštre Mondial de la Corruption par Transparency International, les chercheurs ont dorĂ©navant accĂšs aux perceptions des populations pour Ă©valuer lâĂ©tendue de la corruption au sein de diffĂ©rentes administrations. Dans cet article, nous analysons lâĂ©cart entre les perceptions de la corruption et lâexpĂ©rience concrĂšte de celle-ci en utilisant des donnĂ©es de panel issues dâenquĂȘtes mĂ©nages menĂ©es Ă une Ă©chelle mondiale. Nous comparons ainsi, au sein mĂȘme des populations, les Ă©carts entre expĂ©riences et perceptions de la corruption, afin dâisoler au mieux les mĂ©canismes Ă lâoeuvre dans la construction des perceptions. Nous montrons alors que les Ă©carts entre ces deux types de donnĂ©e peuvent ĂȘtre importants et inĂ©galement distribuĂ©s.(Full text in english)
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