1,354,581 research outputs found
Light pollution is a compound threat to the movement ecology of nocturnal arthropod taxa
No full textSee bottom of 'Meah, R. et al 2025 - README.txt' file
Modelling for turbulent autoignition with split fuel injection
No full textSplit-injection is applied in automotive diesel engines in order to control heat release and pollution production. Injecting fuel prior to the main fuel injection, known as pilot injection, increases premixing and tends to reduce NOx emission. Injecting a portion of the fuel after the main injection has potential for reducing particulate emissions. In order to meet increasingly stringent emission and fuel consumption regulations, modern automotive diesel injectors have been developed with the capacity to deliver of the order of ten separate injection pulses during a single engine stroke. Simulation methods for split-injection engines are required in order to develop more advanced injection strategies with two or more separate fuel-injections. A range of additional combustion applications involve mixing and combustion between multiple streams such as Exhaust Gas Recirculation (EGR) and dual fuel injections. Modelling for the turbulent combustion interactions in multi-stream problems is developed in this thesis in the context of Conditional Moment Closure (CMC) methods.The CMC approach provides modelling of chemical processes in turbulent flows by linking composition fluctuations to the variation of a small number of conditioning variables such as mixture fraction. In order to achieve good accuracy, the conditioning variables must be chosen to minimise compositional fluctuations around the conditional mean. Split-injection diesel engine operation results in complex combustion behaviour in which a single conditioning variable may be insufficient. However multiple-conditioned moment closures, or even double conditional moment closures (DCMC) have not been exploited previously. The objective of this study is to identify the most appropriate conditioning variables for modelling of split-injection diesel engines and to formulate, validate and demonstrate a practical implementation of the DCMC approach for engine-relevant simulations.The thesis begins by developing a new formulation of the DCMC approach that is applicable to a general set of non-conserved conditioning variables, and a set of numerical solution approaches is demonstrated and verified. The choice of conditioning variables is then investigated through direct numerical simulations of autoignition in a turbulent flow with up to three separate fuel injections. In the case with a single injection, fluctuations around the mixture fraction-conditioned mean arise due to variation in mixture fraction dissipation rate affecting the progress of ignition differently at different points in space. In cases with multiple injections, the repeated addition of unreacted fuel also adds to fluctuations around the conditional mean. The high level of conditional fluctuations leads to large errors when employing singly-conditioned first-order conditional moment closure. Alternative doubly conditional moment closure approaches are tested using a priori and a posteriori analyses. Single conditioned first order closure gives extremely poor agreement with the DNS, and the study indicates that double conditioning on mixture fraction and progress variables, such as the sensible enthalpy, outperforms double conditioning on multiple mixture fractions.The feasibility of the zero-dimensional DCMC approach for practical predictive design calculations is then assessed further through simulations of n-heptane spray ignition in constant volume research vessels with single or multiple injections. The experimental flows are simulated by coupling the zero-dimensional first order double conditional moment closure (0D-DCMC) with a commercial CFD code and an efficient Operator Splitting solution method is demonstrated. The predictions show the same trends as the experimental observations, however ignition delays and lift off lengths agree with the measurements only approximately. Reasons for the discrepancies include the uncertainty in the chemical modelling as well as in the ambient temperature surrounding the spray in the experiments. The modelling of conditional cross-scalar dissipation rate is also found to have a significant influence on the flame evolution, with the limiting cases of modelling corresponding to zero correlation or unity correlation between mixture fraction and progress variable giving unrealistic predictions. Conditional cross-dissipation rate modelling corresponding to negative unity correlation gives reasonable predictions, and an argument for why negative mixture fraction–progress variable correlation is expected to be dominant in autoignitive lifted jet flames involving multiple fuel injections is presented. Other aspects of modelling uncertainty with regard to conditional dissipation rates, presumed joint mixture fraction-progress variable probability density functions and first order source term closures will also contribute to the model error, and further development of models suitable for spray autoignition cases would be beneficial.In comparison with the established three-dimensional singly-conditioned moment closure (3D-CMC), the 0D-DCMC model is a promising approach which is expected to be substantially faster than the 3D-CMC approach in most problems of engineering interest. Not withstanding the imperfect predictions, the ability of the zero-dimensional DCMC to describe the whole split-injection process and to provide new insight into the mechanisms involved is encouraging: this implies that only a few DCMC control volumes may be needed in order to model a wide range of flows involving very complex physics, of which split-injection is just one example, and the DCMC approach is therefore recommended for further development.<br/
Noticias MEAH Sección Árabe-Islam, 2024
No full textTesis Doctorales defendidas en el Departamento de Estudios Semíticos (Área de Estudios Árabes e Islámicos)
AÑO 2023:
Paola LUQUE VARGAS. El mustajlaṣ nazarí: génesis, evolución y transmisión (siglos XIII-XVI). Director: Antonio Peláez Rovira. (9 de mayo).
Anas Literatura marroquí expresada en español: indagando en los orígenes. Director: Carmelo Pérez Beltrán. (1 de diciembre).
LIBROS RECIBIDOS EN MISCELÁNEA DE ESTUDIOS ÁRABES Y HEBRAICOS, SECCIÓN ÁRABE-ISLAM
ABU-TARBUSH, José y BARREÑADA, Isaías. Palestina: de los acuerdos de Oslo al apartheid. Madrid: Los Libros de la Catarata, 2023.
AZAOLA, Bárbara, DESRUES, Thierry, H. DE LARRAMENDI, Miguel, PLANET, Ana I. y RAMÍREZ, Ángeles. (eds.). Cambio, crisis y movilizaciones en el Mediterráneo Occidental. Granada: Comares, 2022.
DUCÈNE, Jean-Charles y PREVOST, Virginie. Dictionaire géographique de l’Afrique médiévale. Yāqūt, al-Qazwīnī et al-Ḥimyarī. París: Éditions de la Sorbonne, 2023.
MACÍAS AMORETTI, Juan A. (ed.). Dámqraṭa. Una antología árabe de la de- mocracia en el Norte de África.Colección Madrasa. Granada: Comares, 2022
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
No full text“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
No full textWe 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
Pharmacological insights on the antidepressant, anxiolytic and aphrodisiac potentials of Aglaonema hookerianum Schott
No full textEthnopharmacological relevance: Aglaonema hookerianum Schott is an ethnomedicinally important plant used to treat a variety of diseases, including sexual and depression-like disorders. However, the scientific basis underlying the aforesaid properties have not been well justified. Aim of the study: The present investigation aimed to investigate the anxiolytic, antidepressant and aphrodisiac potentials of methanol leaves extract of A. hookerianum (MEAH) in Swiss albino mice. Materials & methods: Swiss albino mice (20–30 g) were orally administrated with MEAH at the doses ranging from 100 to 400 mg/kg, b.w. The elevated plus maze (EPM) and hole board test (HBT) were performed to determine the anxiolytic activity and the forced swimming test (FST) and tail suspension test (TST) were performed to determine the antidepressant activity of MEAH. Besides, the aphrodisiac activity of MEAH was conducted through the mounting behaviour and orientation behaviour analysis. Diazepam (1 mg/kg, b.w., i.p.) for EPM and HBT; fluoxetine HCl (20 mg/kg, b.w., p.o.) for FST and TST, and sildenafil (5 mg/kg, b.w., p.o.) for the mounting behaviour analysis and orientation behaviour analysis were used as reference drugs. Results: The administration of the MEAH produced a strong (p < 0.001) dose-dependent anxiolytic effects in both HBT and EPM tests. Likewise, the extract revealed a significant (p < 0.001) reduction in the immobility time in both FST and TST as compared to the control group. Besides, the MEAH also found to possess marked aphrodisiac activity complying several facets such as an increase in the sexual performance at the highest dose (400 mg/kg, p.o.) as well as the orientation toward female mice (p < 0.001) at all tested doses. Conclusion: Taken together, MEAH can be recommended as a potent source of neuroprotective and a libido-boosting drug candidate for the management of neurological and sexual disorders
Dispelling the Myths Behind First-author Citation Counts
No full textWe 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
Author, publisher and bookseller : a tripartite synergy in Nigerian book industry
No full textThis work is about the roles of Author, Publisher and Bookseller in Book development in
Nigeria. The paper started by delving into the history of Book Publishing in Nigeria after
which it proceeded by defining who an author, a publisher, and a bookseller is and
expatiated on the indispensable roles of these key actors in Nigerian Book Industry and in
the emerging Information Society. Furthermore, the various constraints to book
development were identified while the paper advised on how the Book Industry can be
further promoted in Nigeria. However, the paper concluded and made recommendations
on how the Book sector can help in enhancing scholarship in the country
The Thursday Murder Club: Launching a megabrand author - a publishing case study
No full textIn 2020, the Christmas book charts in the UK made headlines: Barack Obama’s eagerly awaited autobiography, The Promised Land, was beaten to the top spot by The Thursday Murder Club by Richard Osman, a debut cosy crime novel set in a retirement village. Not only did Osman’s book beat the former US president’s expected bestseller, it also broke records, becoming the fastest-selling debut crime novel of all time. Although Osman has a certain level of fame in the UK from his TV appearances on shows such as Pointless, his celebrity status does not entirely explain the novel’s huge sales. This article tracks the acquisition, publication, and promotion journey of The Thursday Murder Club in order to understand the industry and cultural context of its success and to interrogate the role of celebrity in the creation of author brands. The findings suggest that the unexpected scale of the success of the book owed to a number of factors, including in-depth editing by the novel’s agent, editor, and author to tighten up the plot, an extensive and strategic promotional campaign, the pandemic (which drove interest in the book’s genre and themes), and the quality of the writing. We find that the book’s success was accentuated by Osman’s celebrity status rather than being entirely reliant on it. This research adds to the growing scholarship on celebrity authorship by means of an in-depth case study and provides insight into the processes behind publishing a ‘celebrity’ book and launching a megabrand author
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