1,721,061 research outputs found
Catodi ad ossidi di terre alcaline per impieghi spaziali
No full textIl presente lavoro è stato svolto presso Centrospazio / Consorzio Pisa Ricerche nell’ambito delle attività di ricerca di base volte allo studio dei meccanismi di funzionamento e all’ottimizzazione delle tecnologie al sistema di propulsione FEEP. L’attività è stata avviata nel WP 110 con uno studio volto alla comprensione dei fenomeni fisico-chimici alla base del funzionamento dei catodi termoionici rivestiti di ossidi. Lo studio ha comportato l’analisi dei dati disponibili in letteratura sull’emissione di elettroni da ossidi di terre alcaline e sui loro meccanismi di attivazione e la definizione di adeguati modelli di riferimento teorici.
Nel WP 120 è stata condotta una indagine sperimentale su emettitori ad ossidi a filamento reperibili in commercio, caratterizzandoli elettricamente. Tali emettitori, derivati dalla tecnologia delle valvole termoioniche, offrono prestazioni relativamente interessanti a costi molto contenuti, ed il loro studio ha consentito di approfondire alcune questioni relative alle potenzialità d’impiego di sistemi di questo tipo per la neutralizzazione di fasci ionici.
A completamento dell’attività, nel WP 130 sono state gettate le basi per la realizzazione di un emettitore termoionico ad ossidi con geometria planare individuando meccanismi di produzione, trattamento e deposizione degli ossidi su tali tipi di catodi
Sicurezza nella navigazione: il ruolo del fattore umano
No full textThe main aim of this paper is to examine the role of human factors in the safety of ship transport (shipping).
Particularly, we analyzed the personal, psychosocial and organizational factor that intervene in this context and the consequences on the safety performance and workers’ well-being.
In this review, some shipping accidents and their causes are presented and particular attention will be paid to human error, fatigue and stress, non-technical skills and perception of safety. In the final part of the paper the safety performance and its antecedents in the context of shipping will be extensively examined
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
Safety in shipping: The role of the human factor
No full textThe main aim of this paper is to examine the role of human factors in the safety of ship transport (shipping). Particularly, we analyzed the personal, psychosocial and organizational factor that intervene in this context and the consequences on the safety performance and workers' well-being. In this review, some shipping accidents and their causes are presented and a particular attention will be paid to human error, fatigue and stress, non-technical skills and perception of safety. In the final part of the paper the safety performance and its antecedents in the context of shipping will be extensively examined
Experimental Performance of a Low Power Neutralizer for a Micronewton FEEP Thruster
Full text linkThis paper presents the results of a series of electron emission tests carried out on thermionic neutralizers for a micronewton FEEP thruster. Several different sources have been tested in different experimental arrangements, including filaments and planar oxide cathodes. The filament performance was quite satisfactory, allowing the extraction of a 1 mA electron current with a 0.25 W power consumption. This is appropriate for a FEEP emitter of up to 100 uN thrust. The planar configuration presents more technological challenges. The prototype tested produced 3.3 mA at 720 °C, showing no sign of degradation after 20 hours continuous operation. Power consumption and reliability are still to be improved
Internalized sexual stigma and psychological well-being: exploratory research on italian and belgian gay and lesbian people
No full textNumerous researches have shown that in homosexual people the internalized homophobia is a risk factor for mental health, whereas the social support is a protective factor. Internalized homophobia affects the onset of mental disorders and it’s related to less social support (Mc Gregor et al. 2001; Szymanski et al., 2008). The aim of this research is to understand if the legislative context can influence the psychological well-being. For this reasons we have analyzed the levels of internalized homophobia, anxiety, depression and social support in two groups of gay and lesbian people coming from Italy and Belgium. These two European countries are very different in terms of civil rights of the LGBT population. The sample is composed of 194 adults (M=29 years, SD=9.08). From the analyzed questionnaires (MISS- LG, BDI, STAI, MSPSS) has emerged that the investigated constructions are well related to each other and that the levels of internalized homophobia are higher in the Belgian gay group, who enjoy the same civil rights of the heterosexual people, more than in the Italian one. This particular result could be related to a greater frequency of coming out of Belgians compared to Italians or to a sort of defence reaction of the Italian group to the tests, affected by the continuous negations of their civil rights. Future researches should focus both on the several aspects of the coming- out process and on the family support, which plays a huge role in mental health
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
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