328 research outputs found
Diffraction by a right-angled no-contrast penetrable wedge: recovery of far-field asymptotics
Get PDFWe provide a description of the far-field encountered in the diffraction
problem resulting from the interaction of a monochromatic plane-wave and a
right-angled no-contrast penetrable wedge. To achieve this, we employ a
two-complex-variable framework and use the analytical continuation formulae
derived in (Kunz Assier, QJMAM, 76(2), 2023) to recover the wave-field's
geometrical optics components, as well as the cylindrical and lateral
diffracted waves. We prove that the corresponding cylindrical and lateral
diffraction coefficients can be expressed in terms of certain
two-complex-variable spectral functions, evaluated at some given points
Diffraction by a right-angled no-contrast penetrable wedge: recovery of far-field asymptotics
Get PDFWe provide a description of the far-field encountered in the diffraction problem resulting from the interaction of a monochromatic plane-wave and a right-angled no-contrast penetrable wedge. To achieve this, we employ a two-complex-variable framework and use the analytical continuation formulae derived in (Kunz & Assier, QJMAM, 76(2), 2023) to recover the wavefield’s geometrical optics components, as well as the cylindrical and lateral diffracted waves. We prove that the corresponding cylindrical and lateral diffraction coefficients can be expressed in terms of certain two-complex-variable spectral functions, evaluated at some given points
A contribution to the mathematical theory of diffraction. Part II: Recovering the far-field asymptotics of the quarter-plane problem
Get PDFWe apply the stationary phase method developed in (Assier, Shanin \&
Korolkov, QJMAM, 76(1), 2022) to the problem of wave diffraction by a
quarter-plane. The wave field is written as a double Fourier transform of an
unknown spectral function. We make use of the analytical continuation results
of (Assier \& Shanin, QJMAM, 72(1), 2018) to uncover the singularity structure
of this spectral function. This allows us to provide a closed-form far-field
asymptotic expansion of the field by estimating the double Fourier integral
near some special points of the spectral function. All the known results on the
far-field asymptotics of the quarter-plane problem are recovered, and new
mathematical expressions are derived for the secondary diffracted waves in the
plane of the scatterer
Memoirs of the life and administration of William Cecil Baron Burleigh, Lord High Treasurer of England in the Reign of Queen Elizabeth; including a parallel between the state of government then and now. To which is prefixed a preface to the people of Britain. Together with an appendix of original papers [electronic resource].
No full textDedication signed: R. C., i.e. Raphael Courteville.Electronic reproduction.English Short Title Catalog,Reproduction of original from British Library
Diffraction by a Right-Angled No-Contrast Penetrable Wedge Revisited: A Double Wiener-Hopf Approach
Get PDFIn this paper, we revisit Radlow's innovative approach to diffraction by a
penetra ble wedge by means of a double Wiener-Hopf technique. We provide a
constructive way of obtaining his ansatz and give yet another reason for why
his ansatz cannot be the true solution to the diffraction problem at hand. The
two-complex-variable Wiener-Hopf equation is reduced to a system of two
equations, one of which contains Radlow's ansatz plus some correction term
consisting of an explicitly known integral operator applied to a yet unknown
function, whereas the other equation, the compatibility equation, governs the
behaviour of this unknown function
Diffraction by a Right-Angled No-Contrast Penetrable Wedge: Analytical Continuation of Spectral Functions
Get PDFWe study the problem of diffraction by a right-angled no-contrast penetrable
wedge by means of a two-complex-variable Wiener-Hopf approach. Specifically,
the analyticity properties of the unknown (spectral) functions of the
two-complex-variable Wiener-Hopf equation are studied. We show that these
spectral functions can be analytically continued onto a two-complex dimensional
manifold, and unveil their singularities in . To do so, integral
representation formulae for the spectral functions are given and thoroughly
used. It is shown that the novel concept of additive crossing holds for the
penetrable wedge diffraction problem and that we can reformulate the physical
diffraction problem as a functional problem using this concept
Author Correction: Trained immunity, tolerance, priming and differentiation: distinct immunological processes
Get PDFIn the version of this article initially published, author Raphael Duivenvoorden’s last name was spelt incorrectly as Duivenwoorden. The error has been corrected in the HTML and PDF versions of the article
Gamasiphis bengalensis Bhattacharyya 1966
No full text202. Gamasiphis bengalensis Bhattacharyya, 1966 Gamasiphis (Neogamasiphis) bengalensis Bhattacharyya, 1966: 151. Gamasiphis bengalensis.— Lee, 1970: 49; Bhattacharyya, 1978: 83; Karg, 1987: 306; 1990: 334; 1993b: 182; 1996: 179; Castilho et al., 2012a: 1992; Marchenko, 2013a: 387; 2013b: 178. Type depository. Author´s private collection. Type locality and habitat. Pond Sitala, Sonarpur, 24 Parganas District, West Bengal, India, 2 December 1963, in litter under decaying Pistia stratiotes [Araceae].Published as part of Castilho, Raphael C., Silva, Edmilson S., De, Gilberto J. & Halliday, Bruce, 2016, Catalogue of the family Ologamasidae Ryke (Acari: Mesostigmata), pp. 1-147 in Zootaxa 4197 (1) on page 59, DOI: 10.5281/zenodo.16844
Gamasiphis sextus Vitzthum 1921
No full text259. Gamasiphis sextus Vitzthum, 1921 Gamasiphis (Gamasiphis) sextus Vitzthum, 1921: 10. Gamasiphis sextus.— Karg, 1971: 352; 1987: 306; 1990: 334; 1993b: 182; 1993c: 373; 1996: 179; 2007: 126; Castilho et al., 2012a: 1993; Marchenko, 2013a: 387. Type depository. Author´s private collection. Type locality and habitat. Weimar, Germany, in a greenhouse where Orchids [Orchidaceae] were grown.Published as part of Castilho, Raphael C., Silva, Edmilson S., De, Gilberto J. & Halliday, Bruce, 2016, Catalogue of the family Ologamasidae Ryke (Acari: Mesostigmata), pp. 1-147 in Zootaxa 4197 (1) on page 68, DOI: 10.5281/zenodo.16844
Strategies of Communication in Agonistic Epigrams
Get PDFInscribed agonistic epigrams of the archaic and classical time represent a privileged field of work on strategies of communication because they share topics and function with another major literary genre: the epinician ode. Victorious athletes, in fact, could choose to celebrate their victory either by dedicating a statue with an inscribed epigram or by commissioning an ode to a poet. The two forms had the same function (celebrating the victory), and shared some common topoi and expressions, but the results are radically different, not only because of the extension. The material support of inscriptions influences the poet, who pays great attention to the visual disposal of words and to the relationship of the epigram with the statue it accompanies. Agonistic statues, in fact, become from the fifth century B.C. more and more lifelike and epigrams gradually assume the function of expressing their words. First-person utterances thus become a mean to express victors’ own voice before the future generations with a continuous play on the absence/presence of the dedicator.
Simonides plays a crucial in role in the relationship between the text and the material support, because he is the first author who gives literary dignity to a genre so far considered as “ancillary” like the epigram. As a lyric poet, author of epinician and encomiastic odes, he intends the epigram as a poetic product and not as a mere “complement” of the statue and its base. At the same time, he is well aware that the material support is a fundamental trait of this genre, which makes his art unique: this is the reason why he never forgets to obey to the laws of the stone and to the stylistic conventions which took place in the epigraphic field. The brevity imposed by the material support forces the poet to invent new modes in order to concentrate all the necessary informations in two lines and, possibly, find some artistic variations to the most essential lists.
Another difference between agonistic epigrams and epinician odes is the context of performance: epigrams we know were mainly dedicated in Panhellenic sanctuaries, whereas the great part of epinicians were performed in the victor’s home town. This implies a different mode of self-presentation of the victor in accordance to the audience (local or panhellenic), which becomes particularly evident in those few lucky cases in which we possess both odes and epigrams of the same dedicator (e.g. Hieron of Syracuse)
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