Relation of Experiments to Mathematical Theories of Plasticity

1949 ◽  
Vol 16 (4) ◽  
pp. 349-357
Author(s):  
D. C. Drucker
Keyword(s):  
Plastic Deformation ◽  
Work Hardening ◽  
Bauschinger Effect ◽  
Point Of View ◽  
General Point ◽  
Shearing Stress ◽  
Series Of Experiments ◽  
Thin Walled ◽  
Incremental Strain ◽  
Stress Criteria

Abstract Several classes of mathematical theories of plasticity for work-hardening materials are surveyed and their advantages, disadvantages, and agreement with experiment discussed. Consideration is given to the proper correlation of tests on thin-walled tubes subjected to tension, torsion, and internal pressure in fixed but arbitrary ratio. The continuing debate between octahedral-shearing-stress and maximum-shearing-stress criteria of plastic deformation is re-examined and the more general alternatives are restated. Through an analysis of Osgood’s experimental results, it is made apparent that the more general point of view is required for the best correlation. A series of experiments are outlined which make the distinction between the various criteria of loading or deformation very large instead of just a few per cent as in previous work. In the evaluation of present mathematical theories it is shown that incremental-strain theories avoid obvious drawbacks of the so-called deformation type of theory. The concept of isotropic work hardening, assumed in practically all stress-strain relations, is explored and generalized. Strong limitations indicated by the Bauschinger effect, which cannot appear properly in such theories, are pointed out.

Do Event-Related Brain Potentials Reflect Mental (Cognitive) Operations?

2002 ◽  
Vol 16 (3) ◽  
pp. 129-149 ◽  
Author(s):  
Boris Kotchoubey
Keyword(s):  
Cognitive Processes ◽  
Point Of View ◽  
Internal Variables ◽  
Brain Potentials ◽  
Cognitive Operations ◽  
External Variables ◽  
Series Of Experiments ◽  
Mental Operations ◽  
A Chain ◽  
Processing Mechanisms

Abstract Most cognitive psychophysiological studies assume (1) that there is a chain of (partially overlapping) cognitive processes (processing stages, mechanisms, operators) leading from stimulus to response, and (2) that components of event-related brain potentials (ERPs) may be regarded as manifestations of these processing stages. What is usually discussed is which particular processing mechanisms are related to some particular component, but not whether such a relationship exists at all. Alternatively, from the point of view of noncognitive (e. g., “naturalistic”) theories of perception ERP components might be conceived of as correlates of extraction of the information from the experimental environment. In a series of experiments, the author attempted to separate these two accounts, i. e., internal variables like mental operations or cognitive parameters versus external variables like information content of stimulation. Whenever this separation could be performed, the latter factor proved to significantly affect ERP amplitudes, whereas the former did not. These data indicate that ERPs cannot be unequivocally linked to processing mechanisms postulated by cognitive models of perception. Therefore, they cannot be regarded as support for these models.

Thanato-Laboratorien. Theorien von Tod und Sterben und Elias Canettis Buch gegen den Tod

2020 ◽  
Vol 4 (1) ◽  
pp. 67-86
Author(s):  
Elisabeth Heyne
Keyword(s):  
Human Life ◽  
Death And Dying ◽  
Point Of View ◽  
Visual Images ◽  
Elias Canetti ◽  
History Of ◽  
Series Of Experiments ◽  
First Time ◽  
Textual Form ◽  
Or History

AbstractAlthough visual culture of the 21th century increasingly focuses on representation of death and dying, contemporary discourses still lack a language of death adequate to the event shown by pictures and visual images from an outside point of view. Following this observation, this article suggests a re-reading of 20th century author Elias Canetti. His lifelong notes have been edited and published posthumously for the first time in 2014. Thanks to this edition Canetti's short texts and aphorisms can be focused as a textual laboratory in which he tries to model a language of death on experimental practices of natural sciences. The miniature series of experiments address the problem of death, not representable in discourses of cultural studies, system theory or history of knowledge, and in doing so, Canetti creates liminal texts at the margins of western concepts of (human) life, science and established textual form.

On effect of surface hardening on impact and abrasive wear resistance of Hadfi eld steel

2020 ◽  
pp. 252-255
Author(s):  
V.I. Bolobov ◽  
V.S. Bochkov ◽  
E.V. Akhmerov ◽  
V.A. Plashchinsky ◽  
E.A. Krivokrisenko E.A.
Keyword(s):  
Plastic Deformation ◽  
Wear Resistance ◽  
Abrasive Wear ◽  
Work Hardening ◽  
Surface Hardening ◽  
Cold Work ◽  
Abrasive Wear Resistance ◽  
Hadfield Steel ◽  
Mining Equipment ◽  
Effect Of Surface

On the example of Hadfield steel, as the most common material of fast-wearing parts of mining equipment, the effect of surface hardening by plastic deformation on their impact and abrasive wear resistance is considered. Wear test is conducted on magnetic ironstone as typical representative of abrasive and hard rock. As result of wear of initial samples with hardness of ∼200 HB and samples pre-hardened with different intensities to the hardness of 300, 337 and 368 HB, it is found that during the initial testing period, the initial samples pass the “self-cold-work hardening” stage with increase in hardness to ∼250 HB, which remains virtually unchanged during further tests; the hardness of the pre-hardened samples does not change significantly throughout the tests. It is established that the rate of impact-abrasive wear of pre-hardened samples is significantly (up to 1.4 times) lower than the original ones that are not subjected to plastic deformation, and decreases with increasing degree of cold-work hardening. Preliminary surface hardening by plastic deformation can serve as effective way to increase the service life of fast-wearing working parts of mining equipment.

Deformation Behaviour and Ultrafine Grained Structure Development in Steels with Different Carbon Content Subjected to Severe Plastic Deformation

2007 ◽  
Vol 345-346 ◽  
pp. 45-48 ◽  
Author(s):  
Jozef Zrník ◽  
Sergey V. Dobatkin ◽  
Ondrej Stejskal
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Work Hardening ◽  
Favourable Effect ◽  
Tensile Behaviour ◽  
Dislocation Network ◽  
Strength Increase ◽  
Subgrain Structure ◽  
Low Carbon ◽  
Channel Angle

The article focuses on the results from recent experimental of severe plastic deformation of low carbon (LC) steel and medium carbon (MC) steel performed at increased temperatures. The grain refinement of ferrite respectively ferrite-pearlite structure is described. While LC steel was deformed by ECAP die (ε = 3) with a channel angle φ = 90° the ECAP severe deformation of MC steel was conducted with die channel angle of 120° (ε = 2.6 - 4). The high straining in LC steel resulted in extensively elongated ferrite grains with dense dislocation network and randomly recovered and polygonized structure was observed. The small period of work hardening appeared at tensile deformation. On the other side, the warm ECAP deformation of MC steel in dependence of increased effective strain resulted in more progressive recovery process. In interior of the elongated ferrite grains the subgrain structure prevails with dislocation network. As straining increases the dynamic polygonization and recrystallization became active to form mixture of polygonized subgrain and submicrocrystalline structure. The straining and moderate ECAP temperature caused the cementite lamellae fragmentation and spheroidzation as number of passes increased. The tensile behaviour of the both steels was characterized by strength increase however the absence of strain hardening was found at low carbon steel. The favourable effect of ferrite-pearlite structure modification due straining was reason for extended work hardening period observed at MC steel.

scholarly journals Lessons from the COVID-19 Pandemic on the Use of Artificial Intelligence in Digital Radiology: The Submission of a Survey to Investigate the Opinion of Insiders

Healthcare ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 331
Author(s):  
Daniele Giansanti ◽  
Ivano Rossi ◽  
Lisa Monoscalco
Keyword(s):  
Artificial Intelligence ◽  
General Purpose ◽  
Point Of View ◽  
General Point ◽  
Thoracic Radiography ◽  
Digital Radiology ◽  
Electronic Survey ◽  
Radiology Technicians ◽  
Medical Radiology ◽  
Great Development

The development of artificial intelligence (AI) during the COVID-19 pandemic is there for all to see, and has undoubtedly mainly concerned the activities of digital radiology. Nevertheless, the strong perception in the research and clinical application environment is that AI in radiology is like a hammer in search of a nail. Notable developments and opportunities do not seem to be combined, now, in the time of the COVID-19 pandemic, with a stable, effective, and concrete use in clinical routine; the use of AI often seems limited to use in research applications. This study considers the future perceived integration of AI with digital radiology after the COVID-19 pandemic and proposes a methodology that, by means of a wide interaction of the involved actors, allows a positioning exercise for acceptance evaluation using a general purpose electronic survey. The methodology was tested on a first category of professionals, the medical radiology technicians (MRT), and allowed to (i) collect their impressions on the issue in a structured way, and (ii) collect their suggestions and their comments in order to create a specific tool for this professional figure to be used in scientific societies. This study is useful for the stakeholders in the field, and yielded several noteworthy observations, among them (iii) the perception of great development in thoracic radiography and CT, but a loss of opportunity in integration with non-radiological technologies; (iv) the belief that it is appropriate to invest in training and infrastructure dedicated to AI; and (v) the widespread idea that AI can become a strong complementary tool to human activity. From a general point of view, the study is a clear invitation to face the last yard of AI in digital radiology, a last yard that depends a lot on the opinion and the ability to accept these technologies by the operators of digital radiology.

Changes in the Prognosis of Functional Psychoses Since the Days of Kraepelin

1967 ◽  
Vol 113 (501) ◽  
pp. 813-822 ◽  
Author(s):  
Örnulv Ödegård
Keyword(s):  
Special Problem ◽  
Point Of View ◽  
General Point ◽  
Course Of Illness ◽  
Dynamic Reasoning ◽  
Starting Point ◽  
Functional Psychoses ◽  
External Conditions ◽  
Point Of Departure ◽  
The Universe

My choice of Kraepelin as a point of departure for this lecture has definite reasons. If one wants to stay within the field of clinical psychiatry (as opposed to psychiatric history), that is as far back as one can reasonably go. By this no slight is intended upon the pre-Kraepelinian psychiatrists. For our topic Henry Maudsley would indeed have been a most appropriate starting point, and by no means for reasons of courtesy. His general point of view is admirably sound as a basis for the scientific study of prognosis in psychiatry. I quote: “There is no accident in madness. Causality, not casualty, governs its appearance in the universe, and it is very far from being a good and sufficient practice simply to mark its phenomena and straightway to pass on as if they belonged not to an order but to a disorder of events that called for no explanation.” On the special problem of prognosis he shows his clinical acumen by stating that the outlook is poor when the course of illness is insidious, but this only means that these cases develop their psychoses on the basis of mental deviations which go very far back in the patient's life, so that in fact they are generally in a chronic stage at the time of their first admission to hospital. Here he actually corrects a mistake which is still quite often made. He shows his dynamic attitude when he says that prognosis is to a large extent modified by external conditions, in particular by the attitude of friends and relatives. Maudsley's dynamic reasoning was limited by the narrow framework of the degeneration hypothesis of those days. He had a sceptical attitude towards classification, which he regarded as artificial and dangerously pseudo-exact. His own classification was deliberately provisional, with very wide groups. He held that a description of various sub-forms of chronic insanity was useless, as it would mean nothing but a tiresome enumeration of unconnected details.

Cyclopean Vision, Size Estimation, and Presence in Orthostereoscopic Images

2001 ◽  
Vol 10 (3) ◽  
pp. 312-330 ◽  
Author(s):  
Bernard Harper ◽  
Richard Latto
Keyword(s):  
Visual System ◽  
Three Dimensional ◽  
Point Of View ◽  
Psychophysical Experiment ◽  
Size Estimation ◽  
Human Form ◽  
Image Capture ◽  
Series Of Experiments ◽  
Abstract Shapes ◽  
And Control

Stereo scene capture and generation is an important facet of presence research in that stereoscopic images have been linked to naturalness as a component of reported presence. Three-dimensional images can be captured and presented in many ways, but it is rare that the most simple and “natural” method is used: full orthostereoscopic image capture and projection. This technique mimics as closely as possible the geometry of the human visual system and uses convergent axis stereography with the cameras separated by the human interocular distance. It simulates human viewing angles, magnification, and convergences so that the point of zero disparity in the captured scene is reproduced without disparity in the display. In a series of experiments, we have used this technique to investigate body image distortion in photographic images. Three psychophysical experiments compared size, weight, or shape estimations (perceived waist-hip ratio) in 2-D and 3-D images for the human form and real or virtual abstract shapes. In all cases, there was a relative slimming effect of binocular disparity. A well-known photographic distortion is the perspective flattening effect of telephoto lenses. A fourth psychophysical experiment using photographic portraits taken at different distances found a fattening effect with telephoto lenses and a slimming effect with wide-angle lenses. We conclude that, where possible, photographic inputs to the visual system should allow it to generate the cyclopean point of view by which we normally see the world. This is best achieved by viewing images made with full orthostereoscopic capture and display geometry. The technique can result in more-accurate estimations of object shape or size and control of ocular suppression. These are assets that have particular utility in the generation of realistic virtual environments.

Microstructural Change of Beta Type Titanium Alloy by Intense Plastic Deformation

2006 ◽  
Vol 503-504 ◽  
pp. 705-710 ◽  
Author(s):  
Goroh Itoh ◽  
Hisashi Hasegawa ◽  
Tsing Zhou ◽  
Yoshinobu Motohashi ◽  
Mitsuo Niinomi
Keyword(s):  
Plastic Deformation ◽  
Work Hardening ◽  
Static Recrystallization ◽  
True Strain ◽  
Microstructural Change ◽  
Intense Plastic Deformation ◽  
Rolled Plate ◽  
Al Alloy ◽  
Hot Rolled ◽  
Zr Alloy

Usual static recrystallization treatment and a method to provide intense plastic deformation, ARB namely Accumulative Roll-Bonding, have been applied to two beta type titanium alloys, i.e. Ti-29Nb-13Ta-4.6Zr and Ti-15V-3Cr-3Sn-3Al. Microstructural change as well as work-hardening behavior was examined as a function of plastic strain. Both the work-hardening rate and the hardness at the initial as-hot-rolled state were smaller in the Ti-Nb-Ta-Zr alloy than in the Ti-V-Cr-Sn-Al alloy. Recrystallized grains of 14μm in size were obtained by the usual static recrystallization treatment, which was significantly smaller than that of the starting as-hot-rolled plate of 38μm. No significant change other than flattening and elongating of the original grains was found in the optical microscopic scale. It was revealed, however, from a TEM observation combined with selected area diffraction technique that geometric dynamic recrystallization occurred in the Ti-Nb-Ta-Zr alloy deformed at room temperature by a true strain of 5, resulting in an ultra-fine-grained microstructure where the grain size was roughly estimated to be about 100nm.

scholarly journals I.—The Metamorphosis of the Lizard Gabbros

1886 ◽  
Vol 3 (11) ◽  
pp. 481-489 ◽  
Author(s):  
J. J. H. Teall
Keyword(s):  
Mechanical Energy ◽  
Earth Pressure ◽  
Careful Consideration ◽  
Point Of View ◽  
Igneous Rocks ◽  
General Point ◽  
Present Moment ◽  
General View ◽  
Original Rock ◽  
The Subject

If we take a general view of the present position of geological science, we are struck by the fact that, although there is substantial agreement amongst geologists on matters relating to the origin of the rocks usually designated as aqueous and igneous, the greatest diversity of opinion prevails with regard to the circumstances under which the so-called metamorphic rocks have been produced. Every fragment of evidence calculated to throw light on the origin of these rocks, therefore, deserves the most careful consideration. Of recent years special attention has been directed to the effects of mechanical energy in modifying the mineralogical and structural characters of rocks originally formed by aqueous and igneous agencies; and a suspicion has been aroused that it is in this direction that we must look for a solution of many of the problems connected with the origin of the crystalline schists. A visit to the Lizard Peninsula of Cornwall during the present summer has convinced me of the immense importance of this view so far as that district is concerned. That portion of the peninsula which lies south of a line drawn from Porthalla on the east to Polurrian Cove on the west is formed.partly of igneous rocks—such as gabbro, greenstone, serpentine, and granite—and partly of crystalline schists. The igneous rocks, in certain places, become foliated and sohistose and sometimes show a definite banding due to a variation in the relative proportions of the different constituents. In other words they present characters which are usually regarded as distinctive of the crystalline schists. There is, moreover, evidence to show that these characters are mainly the result of a yielding to earth-pressure subsequent to the consolidation of the original rock. At the present moment, having just returned from the district, I am unable to treat the subject from a general point of view with any prospect of success; but it has occurred to me that some details with regard to one of the rocks may not be without interest to members of the Association.

scholarly journals Local Participation in Tourism Development—Roles of Non-Tourism Related Residents of the Alpine Destination Bad Reichenhall

2019 ◽  
Vol 11 (24) ◽  
pp. 6947 ◽  
Author(s):  
Markus Kantsperger ◽  
Hannes Thees ◽  
Christian Eckert
Keyword(s):  
Developing Countries ◽  
Content Analysis ◽  
Qualitative Content Analysis ◽  
Stakeholder Participation ◽  
Qualitative Interviews ◽  
Tourism Development ◽  
Point Of View ◽  
General Point ◽  
Local Participation ◽  
Important Target

This study applies an adapted approach of the traditional view on local participation in tourism development. First, the study mainly focuses on exploring the patterns behind participation instead of the reasons for participation. Second, a case is chosen that transcends the interest in researching participation in developing countries. Third, the study focuses on non-tourism related residents, an under-researched group of stakeholders. It is thus investigated how non-tourism related residents face the process of participation in tourism development and what the main barriers and drivers are in this regard. To discuss this issue, the study takes a closer look at the case of Bad Reichenhall, an Alpine Destination in Germany. 15 qualitative interviews are conducted with non-tourism related residents and further evaluated through a qualitative content analysis. The results underline that tourism represents a public domain that concerns all stakeholders of a destination. The typology derived throughout the study reflects the heterogeneity of non-tourism related residents, coming up with four types of non-tourism related residents facing participation in tourism development rather differently. Various barriers and drivers are revealed that impact non-tourism related residents from both a personal and general point of view. Non-tourism related residents turn out as a promising and important target group in the discourse of stakeholder participation in tourism development.

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