The wave front in a homogeneous anisotropic medium

1980 ◽  
Vol 70 (6) ◽  
pp. 2097-2101
Author(s):  
M. J. Yedlin
Keyword(s):  
Dispersion Relation ◽  
Wave Front ◽  
Group Velocity ◽  
Anisotropic Medium ◽  
Slowness Surface ◽  
Constant Frequency ◽  
Common Notion ◽  
The Common ◽  
Intuitive Method ◽  
Homogeneous Anisotropic Medium

abstract A simple geometric construction is derived for the shape of the wave front in a homogeneous anisotropic medium. It is shown to be equivalent to the intuitive method of constructing a wave front using Huygen's principle. Although this construction has been referred to and tersely described in the literature (Musgrave, 1970; Kraut, 1963; Duff, 1960), it is instructive to demonstrate its relationship to the common notion of the wave front obtained via consideration of the group velocity. The wave front is shown to be the polar reciprocal of the slowness surface (the dispersion relation at constant frequency). An appreciation of the pole-polar correspondence between the two surfaces allows quick inference of some of the important features of the wave front in a homogeneous anisotropic medium.

3D mapping of kinematic attributes in anisotropic media

Geophysics ◽  
2019 ◽  
Vol 84 (3) ◽  
pp. C159-C170 ◽  
Author(s):  
Yuriy Ivanov ◽  
Alexey Stovas
Keyword(s):  
Anisotropic Medium ◽  
Heterogeneous Media ◽  
Homogeneous Medium ◽  
Anisotropic Media ◽  
Transformation Matrix ◽  
3D Mapping ◽  
Slowness Surface ◽  
Point Correspondence ◽  
Geometric Spreading ◽  
Point To Point

Based on the rotation of a slowness surface in anisotropic media, we have derived a set of mapping operators that establishes a point-to-point correspondence for the traveltime and relative-geometric-spreading surfaces between these calculated in nonrotated and rotated media. The mapping approach allows one to efficiently obtain the aforementioned surfaces in a rotated anisotropic medium from precomputed surfaces in the nonrotated medium. The process consists of two steps: calculation of a necessary kinematic attribute in a nonrotated, e.g., orthorhombic (ORT), medium, and subsequent mapping of the obtained values to a transformed, e.g., rotated ORT, medium. The operators we obtained are applicable to anisotropic media of any type; they are 3D and are expressed through a general form of the transformation matrix. The mapping equations can be used to develop moveout and relative-geometric-spreading approximations in rotated anisotropic media from existing approximations in nonrotated media. Although our operators are derived in case of a homogeneous medium and for a one-way propagation only, we discuss their extension to vertically heterogeneous media and to reflected (and converted) waves.

Dispersion relations of dust lattice waves in two-dimensional honeycomb configuration

2013 ◽  
Vol 79 (5) ◽  
pp. 629-633
Author(s):  
B. FAROKHI
Keyword(s):  
Dispersion Relation ◽  
Group Velocity ◽  
Hexagonal Lattice ◽  
Dispersion Relations ◽  
Two Dimensional ◽  
The Third ◽  
Lattice Waves ◽  
The Waves

AbstractThe linear dust lattice waves propagating in a two-dimensional honeycomb configuration is investigated. The interaction between particles is considered up to distance 2a, i.e. the third-neighbor interactions. Longitudinal and transverse (in-plane) dispersion relations are derived for waves in arbitrary directions. The study of dispersion relations with more neighbor interactions shows that in some cases the results change physically. Also, the dispersion relation in the different direction displays anisotropy of the group velocity in the lattice. The results are compared with dispersion relations of the waves in the hexagonal lattice.

scholarly journals On Smart Contracts and Organisational Performance: A Review of Smart Contracts through the Blockchain Technology

2018 ◽  
Vol 11 (2) ◽  
pp. 137-156 ◽  
Author(s):  
Zaheer Allam
Keyword(s):  
Popular Culture ◽  
Resistance To Change ◽  
Business Management ◽  
Smart Contracts ◽  
Business Sector ◽  
Organisational Performance ◽  
Blockchain Technology ◽  
Management Processes ◽  
Common Notion ◽  
The Common

AbstractAs the Blockchain technology is gaining momentum in popular culture through Cryptocurrencies, its full implication and application to businesses, on a concrete and factual level, is still seen to be in its infancy stage. While the technology provides numerous advantages regarding stability, trust, speed and others, the robustness of the technology is not widely disseminated. This is further coupled by the common notion of resistance to change in business management processes. This paper explores the concept of Smart Contracts through the blockchain technology and its relevance to the business sector and further outlines the advantages and limitations of its applicability as of date.

scholarly journals Curating light: daylight-centric design for promoting wellness

2021 ◽  
Author(s):  
Ryan Alexander
Keyword(s):  
Emotional Impact ◽  
Urban Context ◽  
Connection To Nature ◽  
Sensory Awareness ◽  
Direct Light ◽  
Common Notion ◽  
Experiential Process ◽  
The Common ◽  
Diffused Light ◽  
Design Factors

Daylighting in architecture has traditionally been a practice-based, intuitive and experiential process, based on the common notion that daylight enhances our spatial and sensory awareness. This Thesis tests the effectiveness of daylight as a mechanism for creating a psychological and emotional impact, and promoting wellness within the confines of designed spaces. The creation of the project is based on a Maggie’s Cancer Centre model of patient-centric design. Maggie’s Centers have been traditionally located in suburban settings, where they may be ideally oriented for day-light infiltration and outdoor connectivity. The Maggie’s model promotes three primary design factors: i) abundance of daylight, ii) connection to nature, and iii) a de-institutionalized environment. The design project was purposefully situated within the specific constraint of an urban environment, in downtown Toronto, Ontario; where the goal is to achieve a spatial character that embodies these three design factors where daylight and access to views of nature are limited by the urban context. The project demonstrates a method of daylight centric design that utilizes three primary techniques for daylighting that were extracted from precedent analysis: i) Direct light, ii) Bounced light, and iii) Diffused light. Through the methodical harvesting and manipulation of daylight, the project highlights its potential for positively enhancing patient experience and aptly demonstrates the curation of varied experiential narratives in light.

The Nature of Criminal Disenfranchisement

2018 ◽  
pp. 46-68 ◽  
Author(s):  
Milena Tripkovic
Keyword(s):  
Security Measures ◽  
Criminal Offenders ◽  
Significant Discrepancy ◽  
Normative Analysis ◽  
Common Notion ◽  
The Common ◽  
Equal Citizenship

This chapter sets up the frame for the subsequent normative analysis by seeking to establish the nature of criminal disenfranchisement. Departing from the common notion that criminal disenfranchisement is a form of punishment, the chapter first contrasts the traits of these two sanctions. A significant discrepancy between them is uncovered, which is based on the finding that disenfranchisement may never be considered a principal or sufficient response to crime, that it stands against the principle of ultima ratio, and that it fundamentally targets the offender rather than the offense. Moving away from punishment, the chapter next establishes that, due to its non-penal aims, disenfranchisement is more akin to security measures but nevertheless lacks the preventive, “risk-based” element that characterizes these sanctions. Ultimately, the chapter proposes that criminal disenfranchisement is a sui generis sanction that—rather than pursuing penal goals—targets the equal citizenship of criminal offenders.

Resisting subalternity: Palestinian mimicry and passing in the Israeli cultural industries

2020 ◽  
Vol 42 (7-8) ◽  
pp. 1293-1308
Author(s):  
Amal Jamal ◽  
Noa Lavie
Keyword(s):  
Cultural Production ◽  
Cultural Industries ◽  
Media Industry ◽  
Full Compliance ◽  
Subaltern Agency ◽  
Common Notion ◽  
Creative Workers ◽  
The Media ◽  
The Common

This article explores the complexity of minority creative workers in the media industry. It challenges the common notion in the literature that minority creative workers are fully submissive to the dominant power structure and examines whether such workers could still be conceived as active agents by resisting submission and marginalization even when they cannot influence their own representation in hegemonic media texts. To answer this question, it explores the performances of minority creative workers in a hegemonic cultural industry. To determine whether one can speak of subaltern agency and, if possible, examine how it manifests itself in reality, it addresses the daily performances of Palestinian creative workers during the production of the second season of the Israeli television series, Fauda. Observations conducted during production demonstrate that since in such contexts minority creative workers cannot avoid being projected in negative roles in the media text, they adopt creative subversive practices of passing and transgressive mimicry, resisting full compliance with the production, without endangering their own position. By doing so, the article contributes not only to the emerging field of creative entrepreneurship in cultural production, but also enables determination of common practices of creative subversion in the cultural industries.

On-axis triplications in elastic orthorhombic media

2020 ◽  
Vol 224 (1) ◽  
pp. 449-467
Author(s):  
Shibo Xu ◽  
Alexey Stovas ◽  
Hitoshi Mikada ◽  
Junichi Takekawa
Keyword(s):  
Group Velocity ◽  
Transversely Isotropic ◽  
Model Complexity ◽  
Model Parameters ◽  
S Wave ◽  
Slowness Surface ◽  
S Waves ◽  
Redundant Signal ◽  
Velocity Surface ◽  
Offset Curve

SUMMARY Triplicated traveltime curve has three arrivals at a given distance with the bowtie shape in the traveltime-offset curve. The existence of the triplication can cause a lot of problems such as several arrivals for the same wave type, anomalous amplitudes near caustics, anomalous behaviour of rays near caustics, which leads to the structure imaging deviation and redundant signal in the inversion of the model parameters. Hence, triplication prediction becomes necessary when the medium is known. The research of the triplication in transversely isotropic medium with a vertical symmetry axis (VTI) has been well investigated and it has become clear that, apart from the point singularity case, the triplicated traveltime only occurs for S wave. On contrary to the VTI case, the triplication behaviour in the orthorhombic (ORT) medium has not been well focused due to the model complexity. In this paper, we derive the second-order coefficients of the slowness surface for two S waves in the vicinity of three symmetry axes and define the elliptic form function to examine the existence of the on-axis triplication in ORT model. The existence of the on-axis triplication is found by the sign of the defined curvature coefficients. Three ORT models are defined in the numerical examples to analyse the behaviour of the on-axis triplication. The plots of the group velocity surface in the vicinity of three symmetry axes are shown for different ORT models where different shapes: convex or the saddle-shaped (concave along one direction and convex along with another) indicates the existence of the on-axis triplication. We also show the traveltime plots (associated with the group velocity surface) to illustrate the effect of the on-axis triplication.

The bright side of indebtedness

2018 ◽  
Vol 15 (1) ◽  
pp. 26-34
Author(s):  
Guglielmo Faldetta
Keyword(s):  
Social Relationships ◽  
Design Methodology ◽  
Negative Feeling ◽  
Gift Giving ◽  
Content Type ◽  
The Past ◽  
Common Notion ◽  
Positive Meaning ◽  
The Common ◽  
Bright Side

Purpose The purpose of this paper is to show that indebtedness can have a positive meaning for people who are embedded in social relationships in organizations if it is meant in the light of the notion of gratitude, gift-giving and generalized reciprocity. Design/methodology/approach The study reviews the literature on the common notion of indebtedness and integrates it with the literature on gratitude, gift-giving and generalized reciprocity. Findings The study reveals that through the notion of gratitude, gift-giving and generalized reciprocity people may conceive their indebtedness as gratitude for having received something, so triggering giving behaviors that does not necessarily aim to repay the debt, but to develop and feed their social relationships. Originality/value In the past indebtedness has been conceived as a negative feeling. This study reveals that it may have also a bright side when it is applied to people in flesh and bones, as they are immersed in good quality social relationships.

Paradoxical effects of mild hypoxia and moderate altitude on human visual perception

1992 ◽  
Vol 83 (5) ◽  
pp. 633-636 ◽  
Author(s):  
Thomas E. Schlaepfer ◽  
Peter Bärtsch ◽  
Hans U. Fisch
Keyword(s):  
Cognitive Performance ◽  
Chronic Obstructive ◽  
Moderate Altitude ◽  
Human Visual Perception ◽  
Obstructive Pulmonary Disease ◽  
Hypoxic Conditions ◽  
Paradoxical Effects ◽  
Common Notion ◽  
The Common ◽  
Mild Hypoxia

1. Prolonged (> 10h) exposure to hypoxia and high altitude (> 5000 m) invariably have detrimental effects on cognitive performance. Paradoxically, mild improvements in cognitive function in patients with chronic obstructive pulmonary disease after cessation of oxygen therapy have been reported. 2. We studied in each of 10 healthy subjects the effect of an acute altitude challenge [rapid helicopter transport to the Jungfraujoch (3450 m), experiment 1] and of an acute exposure to mild hypoxia (fractional inspiratory oxygen concentration 14.5%, experiment 2) on a simple test of cognitive performance (the time needed to read briefly displayed letters). 3. Under both hypoxic conditions the time needed to read briefly presented letters decreased, from 12.1 ± sd 3.8 ms to 8.3 ± 1.5 ms (P<0.01) in experiment 1, and from 11.9 ± 1.9 ms to 8.1 ± 1.1 ms (P<0.01) in experiment 2. 4. A rapid and mild hypoxic challenge seems to improve a simple measure of cognitive performance above normal values. The common notion that exposure to hypoxia and altitude invariably impairs cognitive performance may have to be re-evaluated.

Thermoelastic Interaction Between Singularities and Interfaces in an Anisotropic Trimaterial

2007 ◽  
Vol 74 (6) ◽  
pp. 1285-1288
Author(s):  
Seung Tae Choi
Keyword(s):  
Analytic Continuation ◽  
Anisotropic Medium ◽  
Dissimilar Materials ◽  
Infinite Body ◽  
Series Form ◽  
Alternating Technique ◽  
Thermoelastic Interaction ◽  
General Plane ◽  
Homogeneous Anisotropic Medium ◽  
Plane Deformations

The method of analytic continuation and Schwarz-Neumann’s alternating technique were applied to the thermoelastic interaction problems of singularities and interfaces in an anisotropic “trimaterial,” which denotes an infinite body composed of three dissimilar materials bonded along two parallel interfaces. It was assumed that the linear thermoelastic materials are under general plane deformations in which the plane of deformation is perpendicular to the planes of the two parallel interfaces. The author then showed that by alternately applying the method of analytic continuation across two parallel interfaces the solution for the thermoelastic singularities in an anisotropic trimaterial can be obtained in a series form from a solution for the same singularities in a homogeneous anisotropic medium.

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