1,721,725 research outputs found
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
Development of the detector control system and instrumentation for the silicon tracking system in the Compressed Baryonic Matter experiment
No full textThermal Management of the Silicon Tracking System of the CBM Experiment at FAIR
Full text linkDie zunehmende Miniaturisierung von Siliziumbasierter Mikroelektronik in Verbindung mit gestiegenen Anforderungen an die Signalverarbeitung der Detektoren hat dazu geführt, dass Siliziumdetektoren zu einem Eckpfeiler moderner Hochenergiephysikexperimente geworden sind. Solche Detektoren sind von zentraler Bedeutung für Experimente, die sich auf ein tieferes Verständnis des Standardmodells bei Hadronenkollisionen und die Untersuchung der Quantenchromodynamik (QCD) unter extremen Bedingungen bei Schwerionenkollisionen konzentrieren. Die vorliegende Forschungsarbeit bezieht sich auf das Silicon Tracking System (STS) des Compressed Baryonic Matter (CBM) Experiments an der Beschleunigeranlage Facility for Antiproton and Ion Research (FAIR), mit dem der Bereich hoher Dichte des QCD-Phasendiagramms und ein möglicher Phasenübergang zum Quark-Gluon Plasma (QGP) erforscht werden soll.
Das Projekt untersucht einen kritischen Aspekt, der in letzter Zeit für die Entwicklung und den dauerhaften Betrieb moderner Silizium-Tracker in Experimenten der Hochenergiephysik von zentraler Bedeutung geworden ist: das Wärmemanagement. Das CBM-STS ist ein Vorwärtsspektrometer, welches Silizium-Mikrostreifensensoren verwendet, die auf die besonders herausfordernde Vermessung von Zerfallsteilchen mit geringem Impuls in Schwerionenkollisionen spezialisiert sind. Die stark bestrahlten STS-Siliziumsensoren müssen mit minimalem Materialeinsatz gekühlt werden, während die Front-End-Elektronik bis zu 40 kW Leistung in dem 3.5 m³ großen Detektorvolumen verbraucht. Durch theoretische Berechnungen und Simulationen wurde ein neuartiges Kühlungskonzept - die flüssigkeitsunterstützte Luftkühlung - entwickelt. Dieses Konzept integriert die Luftkühlung für die Siliziumsensoren und die Flüssigkeitskühlung für die Front-End-Elektronik, um die Anforderungen an das Wärmemanagement auszugleichen und gleichzeitig das Materialbudget zu minimieren.
Das Kühlkonzept wurde experimentell unter realistischen Betriebsbedingungen mit dem CBM-STS Thermal Demonstrator verifiziert, der gemeinsam an der Universität Tübingen und dem GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt entwickelt und gebaut wurde. Dies hat entscheidende Erkenntnisse über die Betriebsparameter für die STS-Kühlung geliefert und die Eignung von Prototyp- und Vorserien-Detektorkomponenten sowie deren Integrationsmethoden unter STS-ähnlichen Randbedingungen bewertet. Die Ergebnisse sind von entscheidender Bedeutung zur Ermöglichung der Serienproduktion der Detektorkomponenten, um die langfristige Zuverlässigkeit des CBM-STS zu gewährleisten. Die Systemintegration ist für 2024-25 geplant und die Datennahme mit hochintensiven Schwerionenstrahlen bei FAIR wird für 2028-29 erwartet.The ever-growing miniaturisation of silicon microelectronics, coupled with detector signal processing requirements, has established silicon detectors as a cornerstone in modern high-energy physics experiments. These detectors are pivotal for experiments focused on a deeper understanding of the Standard Model in hadron collisions and the study of Quantum Chromodynamics (QCD) in extreme conditions with heavy-ion collisions. This research is focused on the Silicon Tracking System (STS) of the Compressed Baryonic Matter (CBM) experiment at the Facility for Antiproton and Ion Research (FAIR), designed to explore the high-density regime of the QCD phase diagram and a potential phase transition to the Quark-Gluon Plasma (QGP).
This project is focused on a critical aspect that has recently become central to the design and sustained operation of modern silicon trackers in high-energy physics experiments - Thermal Management. The CBM-STS, a forward spectrometer using silicon microstrip sensors specialised in tracking of low-momentum particles produced in heavy-ion collisions, presents a distinctive challenge. The highly irradiated STS silicon sensors must be cooled by introducing minimal material, while the nearby front-end electronics dissipate up to 40 kW of power within a 3.5 m³ detector volume. Through theoretical calculations and simulations, a novel cooling concept - Liquid-Assisted Air Cooling - was developed. This concept integrates air cooling for the silicon sensors and liquid cooling for the front-end electronics to balance thermal management needs while minimising material budget.
The cooling concept was experimentally verified under realistic operational conditions using the CBM-STS Thermal Demonstrator, jointly designed and built at the University of Tübingen and GSI Helmholtz Centre for Heavy Ion Research in Darmstadt. This has provided critical insights into the operating parameters for STS cooling, and assessed the suitability of prototype and pre-production detector components, along with their integration methods in STS-like boundary conditions. The findings are essential for ensuring the long-term reliability of the CBM-STS as it approached its series production phase, with system integration scheduled for 2024-25 and data-taking with high-intensity heavy-ion beams at FAIR expected in 2028-29
Investigation of thermal and structural integrity of modules and ladders of Silicon Tracking System of the CBM experiment
No full textThe Compressed Baryonic Matter (CBM) at the Facility for Antiproton and Ion Research (FAIR) is a fixed target experiment designed to investigate the properties of strongly interacting matter in the region of high net-baryon density. The Silicon Tracking System (STS) is the core detector of the CBM experiment and aims to track and measure the momentum of the charged particles. The STS detector comprises of 876 double sided silicon micro-strip sensors connected via micro cables to the Front-End Boards (FEBs) which are kept outside the detector acceptance of 2.5° to 25°. These sensors are mounted on 106 carbon fiber ladders which includes standard ladders and central ladders with an opening for the beam-pipe. For good particle tracking accuracy in the CBM, the silicon sensors must be mounted on the ladders with extremely high precision, minimizing misalignment and optimizing the spatial resolution of the detector.
The experimental operating conditions of STS present challenges to the electronics due to a highly variable thermal environment. A significant portion of the thesis focuses on the thermal studies of the STS components. This involves a detailed investigation of the requirements for thermal interface materials (TIMs) between the FEBs and the cooling shelves. The study includes optimization techniques for adhesive application and thermal testing to ensure the effectiveness of the TIMs. To ensure the reliable functioning of FEBs under significant temperature variations, thermal cycling tests were conducted, and potential failure scenarios have been analyzed.
The main focus of the thesis is the understanding of the structural integrity of the STS detector. It is investigated how the STS ladders, essential for supporting the silicon sensors, are put together and how they perform. The design and quality assurance processes for carbon fiber ladders are examined, followed by a step-by-step description of the ladder assembly procedure. The evolution of the ladder assembly procedures, from initial prototypes to fully functional ladders with the required mounting precision are highlighted. The developed procedure is designed to be iterative and easily adaptable for producing 106 STS ladders.
The final section of the thesis addresses the vibration challenges encountered by the STS ladders due to air cooling, which is essential for maintaining the sensor performance. It describes the experimental setups used to measure the eigenfrequencies and vibrations on the sensor surface under airflow conditions. The study uses a perforated tube to direct airflow onto the sensor surfaces and highlights the performance differences between the standard and central ladders.
Through the analysis of vibration magnitude, the impact of airflow on the stability of the
silicon sensors once they are mounted on the ladders, is evaluated. These findings underline the significance of effective vibration control to maintain sensor stability. This thesis provides a comprehensive understanding of both thermal management and structural integrity of the STS. Through extensive testing of TIM and thermal cycling of the FEBs, the last step of the module assembly process has been optimized, resulting in a reliable TIM now used in the series production of the modules. Along this work, significant progress has been made in developing the ladder assembly procedure, which is now being implemented for all the ladders, with series production already underway. The central ladder assembly procedure has been optimized and validated with a prototype ladder. The vibration measurements have established the boundary conditions for airflow through the perforated tube, ensuring the mechanical integrity and necessary cooling to prevent thermal runaway
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
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
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