scholarly journals Virtual paleontology: computer-aided analysis of fossil form and function

2014 ◽  
Vol 88 (4) ◽  
pp. 633-635 ◽  
Author(s):  
Imran A. Rahman ◽  
Selena Y. Smith

‘Virtual paleontology’ entails the use of computational methods to assist in the three-dimensional (3-D) visualization and analysis of fossils, and has emerged as a powerful approach for research on the history of life. Three-dimensional imaging techniques allow poorly understood or previously unknown anatomies of fossil plants, invertebrates, and vertebrates, as well as microfossils and trace fossils, to be described in much greater detail than formerly possible, and are applicable to a wide range of preservation types and specimen sizes (Table 1). These methods include non-destructive high-resolution scanning technologies such as conventional X-ray micro-tomography and synchrotron-based X-ray tomography. In addition, form and function can be rigorously investigated through quantitative analysis of computer models, for example finite-element analysis.

2019 ◽  
Vol 56 (6) ◽  
pp. 885-892 ◽  
Author(s):  
Louis King ◽  
Abdelmalek Bouazza ◽  
Anton Maksimenko ◽  
Will P. Gates ◽  
Stephen Dubsky

The measurement of displacement fields by nondestructive imaging techniques opens up the potential to study the pre-failure mechanisms of a wide range of geotechnical problems within physical models. With the advancement of imaging technologies, it has become possible to achieve high-resolution three-dimensional computed tomography volumes of relatively large samples, which may have previously resulted in excessively long scan times or significant imaging artefacts. Imaging of small-scale model piled embankments (142 mm diameter) comprising sand was undertaken using the imaging and medical beamline at the Australian Synchrotron. The monochromatic X-ray beam produced high-resolution reconstructed volumes with a fine texture due to the size and mineralogy of the sand grains as well as the phase contrast enhancement achieved by the monochromatic X-ray beam. The reconstructed volumes were well suited to the application of digital volume correlation, which utilizes cross-correlation techniques to estimate three-dimensional full-field displacement vectors. The output provides insight into the strain localizations that develop within piled embankments and an example of how advanced imaging techniques can be utilized to study the kinematics of physical models.


2017 ◽  
Vol 24 (1) ◽  
pp. 240-247 ◽  
Author(s):  
M. Álvarez-Murga ◽  
J. P. Perrillat ◽  
Y. Le Godec ◽  
F. Bergame ◽  
J. Philippe ◽  
...  

X-ray tomography is a non-destructive three-dimensional imaging/microanalysis technique selective to a wide range of properties such as density, chemical composition, chemical states and crystallographic structure with extremely high sensitivity and spatial resolution. Here the development of in situ high-pressure high-temperature micro-tomography using a rotating module for the Paris–Edinburgh cell combined with synchrotron radiation is described. By rotating the sample chamber by 360°, the limited angular aperture of ordinary high-pressure cells is surmounted. Such a non-destructive high-resolution probe provides three-dimensional insight on the morphological and structural evolution of crystalline as well as amorphous phases during high pressure and temperature treatment. To demonstrate the potentials of this new experimental technique the compression behavior of a basalt glass is investigated by X-ray absorption tomography, and diffraction/scattering tomography imaging of the structural changes during the polymerization of C60 molecules under pressure is performed. Small size and weight of the loading frame and rotating module means that this apparatus is portable, and can be readily installed on most synchrotron facilities to take advantage of the diversity of three-dimensional imaging techniques available at beamlines. This experimental breakthrough should open new ways for in situ imaging of materials under extreme pressure–temperature–stress conditions, impacting diverse areas in physics, chemistry, geology or materials sciences.


Author(s):  
Erik Gray

Love begets poetry; poetry begets love. These two propositions have seemed evident to thinkers and poets across the Western literary tradition. Plato writes that “anyone that love touches instantly becomes a poet.” And even today, when poetry has largely disappeared from the mainstream of popular culture, it retains its romantic associations. But why should this be so—what are the connections between poetry and erotic love that lead us to associate them so strongly with one another? An examination of different theories of both love and poetry across the centuries reveals that the connection between them is not merely an accident of cultural history—the result of our having grown up hearing, or hearing about, love poetry—but something more intrinsic. Even as definitions of them have changed, the two phenomena have consistently been described in parallel terms. Love is characterized by paradox. Above all, it is both necessarily public, because interpersonal, and intensely private; hence it both requires expression and resists it. In poetry, especially lyric poetry, which features its own characteristic paradoxes and silences, love finds a natural outlet. This study considers both the theories and the love poems themselves, bringing together a wide range of examples from different eras in order to examine the major structures that love and poetry share. It does not aim to be a comprehensive history of Western love poetry, but an investigation into the meaning and function of recurrent tropes, forms, and images employed by poets to express and describe erotic love.


2021 ◽  
Vol 1 ◽  
pp. 3219-3228
Author(s):  
Koray Benli ◽  
Jonathan Luntz ◽  
Diann Brei ◽  
Wonhee Kim ◽  
Paul Alexander ◽  
...  

AbstractPneumatically activated systems enable myriad types of highly functional inflatables employing a wide range of architectural approaches affecting their form and function, making systematic conceptual design difficult. A new architectural class of pneumatically activated systems, constrained layer inflatable systems, consists of hierarchically architected flat layers of thin airtight bladders that are internally and/or externally constrained to generate a variety of functionalities. The highly hierarchical architectural structure of constrained layer inflatable systems coincides with the hierarchy of produced functions, providing an opportunity for the development of a functional architectural decomposition, capturing the inherent relationship between architectural and functional hierarchies. The basis of the approach is conveyed through the design of an example constrained layer inflatable system. This approach empowers the systematic understanding of the interrelated architectural and functional breakdown of constrained layer inflatable systems, enabling designers to iteratively analyze, synthesize, and re-synthesize the components of the system improving existing designs and exploring new concepts.


1995 ◽  
Vol 39 ◽  
pp. 109-117
Author(s):  
Burkhard Beckhoff ◽  
Birgit Kanngießer

X-ray focusing based on Bragg reflection at curved crystals allows collection of a large solid angle of incident radiation, monochromatization of this radiation, and condensation of the beam reflected at the crystal into a small spatial cross-section in a pre-selected focal plane. Thus, for the Bragg reflected radiation, one can achieve higher intensities than for the radiation passing directly to the same small area in the focal plane. In that case one can profit considerably from X-ray focusing in an EDXRF arrangement. The 00 2 reflection at Highly Oriented Pyrolytic Graphite (HOPG) crystals offers a very high intensity of the Bragg reflected beam for a wide range of photon energies. Furthermore, curvature radii smaller than 10 mm can be achieved for HOPG crystals ensuring efficient X-ray focusing in EDXRF applications. For the trace analysis of very small amounts of specimen material deposited on small areas of thin-filter backings, HOPG based X-ray focusing may be used to achieve a very high intensity of monochromatic excitation radiation.


2021 ◽  
pp. 096739112199822
Author(s):  
Ahmed I Abou-Kandil ◽  
Gerhard Goldbeck

Studying the crystalline structure of uniaxially and biaxially drawn polyesters is of great importance due to their wide range of applications. In this study, we shed some light on the behaviour of PET and PEN under uniaxial stress using experimental and molecular modelling techniques. Comparing experiment with modelling provides insights into polymer crystallisation with extended chains. Experimental x-ray diffraction patterns are reproduced by means of models of chains sliding along the c-axis leading to some loss of three-dimensional order, i.e. moving away from the condition of perfect register of the fully extended chains in triclinic crystals of both PET and PEN. This will help us understand the mechanism of polymer crystallisation under uniaxial stress and the appearance of mesophases in some cases as discussed herein.


Transilvania ◽  
2021 ◽  
pp. 75-84
Author(s):  
Mona Arhire

Emphasis, a well-acknowledged stylistic device, is a carrier of a considerable load of emotional content in the fictional dialogue. Its manifestation can take sundry forms and can be attached to a wide range of feelings and can take different degrees of intensity, all of which determines the creation of the atmosphere and impacts the reception by the readership. This paper reports on the investigation of the occurrence of emphasis embedded in the dialogic utterances of John Fowles’ novel Mantissa. The focus lies on the relation between the formal construction of emphatic sentences and the functional values deriving therefrom. The study entails a comparative analysis of emphatic utterances depicted from the English original text and its translation into Romanian. The three research questions refer to the comparative-contrastive realization of emphatic sentences in the two languages, to the extent to which the functional component succeeds in being transferred to the target language and to possible means of compensation when structural differences pose translational problems. The analysis is structured along a typology of sentences adapted to the nature of the text under scrutiny and to the aims of this study. The findings and conclusions ultimately indicate the importance of establishing a relation between form and function in matter of emphasis in the literary dialogue as an act of communication depending on linguistic devices for its effectiveness.


2019 ◽  
Author(s):  
Tilman Venzl

In the 18th century, as many as 300 German-language plays were produced with the military and its contact and friction with civil society serving as focus of the dramatic events. The immense public interest these plays attracted feeds not least on the fundamental social structural change that was brought about by the establishment of standing armies. In his historico-cultural literary study, Tilman Venzl shows how these military dramas literarily depict complex social processes and discuss the new problems in an affirmative or critical manner. For the first time, the findings of the New Military History are comprehensively included in the literary history of the 18th century. Thus, the example of selected military dramas – including Lessing's Minna von Barnhelm and Lenz's Die Soldaten – reveals the entire range of variety characterizing the history of both form and function of the subject.


2017 ◽  
Vol 77 (11) ◽  
pp. 447-455 ◽  
Author(s):  
Chun Tan ◽  
Sohrab Randjbar Daemi ◽  
Daniel J.L. Brett ◽  
Paul R. Shearing

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