1,721,040 research outputs found
Advanced Techniques for Border Security: Contributions to the ENTRANCE and MULTISCAN 3D Projects.
No full textL'obiettivo di questa tesi di dottorato è fornire contributi significativi all'avanzamento delle tecniche di interrogazione a neutroni e fotofissione nell'ambito dei progetti ENTRANCE e MULTISCAN 3D. Entrambi sono iniziative finanziate dall'UE dedicate allo sviluppo e alla sperimentazione di sistemi innovativi di ispezione non invasivi per contrastare il traffico illecito di materiali pericolosi o merci di contrabbando all'interno di container merci transfrontalieri. Questa ricerca comprende studi di simulazione, test sperimentali, partecipazione a campagne sul campo e lo sviluppo di nuovi sistemi di rilevamento.
In primo luogo, questo lavoro ha realizzato uno studio di simulazione dettagliato del sistema di interrogazione a neutroni etichettati utilizzando neutroni da 14 MeV all'interno del progetto ENTRANCE. La simulazione si è concentrata sull'ottimizzazione della geometria del sistema e ha fornito importanti intuizioni su aspetti chiave come gli spettri di tempo di volo, la deposizione di energia e gli effetti dei neutroni retro-diffusi. Inoltre, questa tesi presenta i risultati dei test sul campo condotti per valutare le prestazioni del sistema di interrogazione a neutroni sviluppato come parte del progetto ENTRANCE. Questi test, svolti al Porto di Rijeka nel maggio 2023, hanno dimostrato l'alta precisione del sistema nell'identificare esplosivi e una moderata efficacia nel rilevare droghe, su un totale di 18 container simulati e 18 container commerciali.
Questa ricerca ha anche esplorato l'uso della reazione nucleare 9Be(d,n)10B per generare la sorgente di neutroni necessaria per la tecnica di interrogazione nel progetto MULTISCAN 3D. Questo approccio è stato motivato dalla necessità di sostituire la sorgente di neutroni a base di trizio (14 MeV) utilizzata in ENTRANCE, affrontando così le problematiche di sicurezza e logistiche associate ai sistemi a base di trizio. Gli esperimenti condotti all'acceleratore Van de Graaff (INFN di Legnaro) hanno dimostrato con successo la capacità di questa reazione di produrre uno spettro continuo di neutroni. Il rilevamento di picchi di raggi gamma in determinati materiali ha ulteriormente confermato l'efficacia della reazione e il suo potenziale per le applicazioni di interrogazione a neutroni.
Inoltre, questa tesi introduce due innovativi sistemi di rilevamento per applicazioni di fotofissione in entrambi i progetti. Il primo è uno scintillatore a neutroni ZnS:Ag/LiBO/PDMS, che ha dimostrato eccellente efficienza di rilevamento dei neutroni termici, flessibilità e forti capacità di rifiuto dei raggi gamma. Il secondo sistema è un'unità compatta di rilevamento dei raggi gamma costituita da uno scintillatore organico accoppiato con un array SiPM. Questa configurazione è stata valutata in diverse configurazioni, comprese due scintillatori organici (EJ-276G e EJ-309) e tre array SiPM (AdvanSiD-NUV, Hamamatsu e Ketek). Ogni configurazione è stata studiata in termini di risoluzione energetica, risoluzione temporale e discriminazione neutroni/raggi gamma.The objective of this Ph.D. thesis is to make significant contributions to the advancement of neutron interrogation and photofission techniques within the framework of the ENTRANCE and MULTISCAN 3D projects. Both are EU-funded initiatives dedicated to developing and testing innovative, non-intrusive inspection systems to combat the illicit trafficking of hazardous materials or contraband items in cross-border cargo containers. This research encompasses simulation studies, experimental testing, participation in field campaigns, and the development of novel detection systems.
First, this work involved a detailed simulation study of the tagged neutron interrogation system using 14 MeV neutrons within the ENTRANCE project. The simulation focused on optimizing the system’s geometry and provided valuable insights into key aspects such as time-of-flight spectra, energy deposition, and back-scattered neutron effects. Furthermore, this thesis presents the results of field tests conducted to evaluate the performance of the neutron interrogation system developed as part of the ENTRANCE project. These tests, carried out at the Port of Rijeka in May 2023, demonstrated the system's high accuracy in identifying explosives and moderate effectiveness in detecting drugs across a total of 18 mock-up containers and 18 commercial containers.
This research also explored the use of the 9Be(d,n)10B nuclear reaction to generate the neutron source needed for the interrogation technique in the MULTISCAN 3D project. This approach was motivated by the need to replace the tritium-based neutron source (14 MeV) employed in ENTRANCE, thereby addressing safety and logistical challenges associated with tritium-based systems. Experiments conducted at the Van de Graaff accelerator (INFN in Legnaro) successfully demonstrated the ability of this reaction to produce a continuous neutron spectrum. The detection of gamma-ray peaks in certain materials further confirmed the reaction’s effectiveness and its potential for neutron interrogation applications.
Additionally, this thesis introduces two innovative detection systems for photofission applications in both projects. The first is a ZnS:Ag/LiBO/PDMS neutron scintillator, which demonstrated excellent thermal neutron detection efficiency, flexibility, and strong gamma-ray rejection capabilities. The second system is a compact gamma-ray detection unit consisting of an organic scintillator coupled with a SiPM array. This setup was evaluated in various configurations, including two organic scintillators (EJ-276G and EJ-309) and three SiPM arrays (AdvanSiD-NUV, Hamamatsu, and Ketek). Each configuration was studied in terms of its energy resolution, time resolution, and neutron/gamma-ray discrimination
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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