Alfred nobel.

Science.gov (United States)

Holmin, L R

1996-10-01

Alfred Nobel never spoke publicly about his problems of ill health, but a detailed, subjective record has recently been published in the form of 216 letters written to his mistress during an 18-year period. His descriptions of constant pain, debilitating migraine, and "paralyzing" fatigue permit a hypothesis that he might have had a long struggle with fibromyalgia. This does not preclude his having suffered other illnesses as well. He thought he had heart disease, which his physicians denied until his final years, when he was diagnosed with angina pectoris. He died of a cerebral hemorrhage in 1896 at the age of 63. His letters describe a 30-year search for diagnosis from the best physicians in Europe. He was ridiculed by many people as a hypochondriac, and he never received a diagnosis for "the pain that will not go away." This may well have contributed to the bitterness and depression of his final years. Increasing worldwide interest and research in this elusive syndrome will hopefully prevent a repetition of the Nobel story of a century ago.

Transitions between Taylor vortices and spirals via wavy Taylor vortices and wavy spirals

International Nuclear Information System (INIS)

Hoffmann, Ch; Altmeyer, S; Pinter, A; Luecke, M

2009-01-01

We present numerical simulations of closed wavy Taylor vortices and of helicoidal wavy spirals in the Taylor-Couette system. These wavy structures appearing via a secondary bifurcation out of Taylor vortex flow and out of spiral vortex flow, respectively, mediate transitions between Taylor and spiral vortices and vice versa. Structure, dynamics, stability and bifurcation behaviour are investigated in quantitative detail as a function of Reynolds numbers and wave numbers for counter-rotating as well as corotating cylinders. These results are obtained by solving the Navier-Stokes equations subject to axial periodicity for a radius ratio η=0.5 with a combination of a finite differences method and a Galerkin method.

Alfred Adler y la psicología académica / Alfred Adler and the academic psychology

OpenAIRE

Lück, Helmut E.; Universidad de Distancia-Hagen (Alemania)

2016-01-01

El presente trabajo tiene como tema las conflictivas relaciones entre Alfred Adler y la psicología académica de su época. La actitud ambivalente del fundador de la psicología individual fue causada, muy probablemente, por su fracaso para conseguir el permiso oficial para dictar clases en la Universidad de Viena, y se fortaleció por las actitudes decididamente antiacadémicas de algunos de sus seguidores. En el marco del presente estudio se contrasta esto con los planteamientos de dos important...

Alfred Kongo, intiimse maalilaadi meister / Juta Kivimäe

Index Scriptorium Estoniae

Kivimäe, Juta, 1952-

2001-01-01

Alfred Kongost, tema loomingust. A. Kongo 95. sünniaastapäeva tähistav näitus Adamson-Ericu muuseumis 10. X-11. XI ja 9. XI toimub mälestusteõhtu. Näha saab Tiina Pargi 1984. a. filmi A. Kongost

Preliminary hard and soft bottom seafloor substrate map derived from an unsupervised classification of gridded backscatter and bathymetry derivatives at Swains Island, Territory of American Samoa, USA.

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Preliminary hard and soft seafloor substrate map derived from an unsupervised classification of multibeam backscatter and bathymetry derivatives at Swains Island,...

Taylor-Made Libraries

Science.gov (United States)

Lonergan, David

2011-01-01

Frederick Winslow Taylor (1856-1915) was an efficiency expert whose concerns were less about avoiding worker fatigue and more about increasing profit margins by any means necessary. Taylor was devoted to finding the One Best Way to carry out a task and then training workers to do that task unvaryingly; attempts by employees to improve their own…

Ceramic superconductivity research at Alfred Univ

International Nuclear Information System (INIS)

Snyder, R.L.

1990-01-01

A survey of the science and technology advances made by the research groups at Alfred will be presented. These ranges on the technology side from the first melt-textured and glass ceramic superconductors to recently demonstrating that 123 thin films can be deposited below the superconducting transition at atmospheric pressure using an aerosol plasma deposition technique. On the science side advances in understanding have come from looking at the crystal structures, high and low temperature reactions, phase equilibria, effects of doping and XRD standards. Recent advances will be summarized

Alfred Jules Aver's induction and Marxian historical evolution: It's ...

African Journals Online (AJOL)

Alfred Jules Aver's induction and Marxian historical evolution: It's lessons for the current economic global crisis. ... Economic liberalism, political manipulation and gross capitalism have been given as the major causes of the present situation in the world economy. It is on this touchstone that we tried to examine the Marxian ...

Who believes in the Taylor Principle?

DEFF Research Database (Denmark)

Stadtmann, Georg; Pierdzioch; Rülke

2012-01-01

The Livingston survey data are used to investigate whether economists’ forecasts are consistent with the Taylor principle. Consistency with the Taylor principle is strong for academics and Federal Reserve economists, and less strong for private-sector economists.......The Livingston survey data are used to investigate whether economists’ forecasts are consistent with the Taylor principle. Consistency with the Taylor principle is strong for academics and Federal Reserve economists, and less strong for private-sector economists....

Apostle of Freedom: Alfred Adler and His British Disciples

Science.gov (United States)

Hirsch, Pam

2005-01-01

The psychology of Alfred Adler is traditionally considered to be one of the three so-called in-depth or psychoanalytic therapies, the other two being the theories of Sigmund Freud and Carl Gustav Jung. This article demonstrates that Adler's Individual Psychology was especially influential on teachers in Vienna between the two world wars. There…

Kurt Alfred Georg Mendelssohn 7 January 1906 - 18 September 1980

International Nuclear Information System (INIS)

Shoenberg, D.

1983-01-01

The life, career and main themes of scientific achievement of Kurt Alfred Georg Mendelssohn are described in detail under the headings: early life in Germany, scientific work, early work in Germany, superconductivity, transport properties of metals, liquid helium, medical physics, Oxford and later life. (U.K.)

Non-Taylor magnetohydrodynamic self-organization

International Nuclear Information System (INIS)

Zhu, Shao-ping; Horiuchi, Ritoku; Sato, Tetsuya.

1994-10-01

A self-organization process in a plasma with a finite pressure is investigated by means of a three-dimensional magnetohydrodynamic simulation. It is demonstrated that a non-Taylor finite β self-organized state is realized in which a perpendicular component of the electric current is generated and the force-free(parallel) current decreases until they reach to almost the same level. The self-organized state is described by an MHD force-balance relation, namely, j perpendicular = B x ∇p/B·B and j parallel = μB where μ is not a constant, and the pressure structure resembles the structure of the toroidal magnetic field intensity. Unless an anomalous perpendicular thermal conduction arises, the plasma cannot relax to a Taylor state but to a non-Taylor (non-force-free) self-organized state. This state becomes more prominent for a weaker resistivity condition. The non-Taylor state has a rather universal property, for example, independence of the initial β value. Another remarkable finding is that the Taylor's conjecture of helicity conservation is, in a strict sense, not valid. The helicity dissipation occurs and its rate slows down critically in accordance with the stepwise relaxation of the magnetic energy. It is confirmed that the driven magnetic reconnection caused by the nonlinearly excited plasma kink flows plays the leading role in all of these key features of the non-Taylor self-organization. (author)

Alfred: Dvořák’s first opera and its fate

Czech Academy of Sciences Publication Activity Database

Kratochvílová, Markéta

-, č. 3 (2014), s. 7-11 ISSN 1211-0264 Institutional support: RVO:68378076 Keywords : Gerd Albrecht * Adolf Heller * Karl Theodor Körner * opera * Antonín Dvořák * Alfred Subject RIV: AL - Art, Architecture, Cultural Heritage

Alfred North Whitehead's Approach to Education: Its Value for Religious Education.

Science.gov (United States)

Hill, Brennan

1990-01-01

Examines Alfred North Whitehead's educational theories and the value these theories possess for religious education. Outlines the application of Whitehead's theories to religious education. Expounds on Whitehead's theory of the threefold rhythm of the educational process: romance, precision, and generalization. (RW)

Taylor instability in rhyolite lava flows

Science.gov (United States)

Baum, B. A.; Krantz, W. B.; Fink, J. H.; Dickinson, R. E.

1989-01-01

A refined Taylor instability model is developed to describe the surface morphology of rhyolite lava flows. The effect of the downslope flow of the lava on the structures resulting from the Taylor instability mechanism is considered. Squire's (1933) transformation is developed for this flow in order to extend the results to three-dimensional modes. This permits assessing why ridges thought to arise from the Taylor instability mechanism are preferentially oriented transverse to the direction of lava flow. Measured diapir and ridge spacings for the Little and Big Glass Mountain rhyolite flows in northern California are used in conjunction with the model in order to explore the implications of the Taylor instability for flow emplacement. The model suggests additional lava flow features that can be measured in order to test whether the Taylor instability mechanism has influenced the flows surface morphology.

Le Corbusier, Alfred Roth y el color

Directory of Open Access Journals (Sweden)

Angelica Fernández-Morales

2014-07-01

Full Text Available This article discusses the relationship between Le Corbusier and Alfred Roth, a member of the Paris office between 1927 and 1928. It also deals with the influence that this period had with reference to an important factor in Roth’s professional development, as in Le Corbusier’s later works: the use of colour in his architecture. This article takes the position that Roth, given his close friendship with Mondrian, was an important figure in turning Le Corbusier’s work towards greater use of primary colours and aesthetic neoplasticism.

[Alfred Ritscher. Reval an der schwelle zur neuzeit. T. 2] / Paul Kaegbein

Index Scriptorium Estoniae

Kaegbein, Paul

2006-01-01

Arvustus: Ritscher, Alfred. Reval an der schwelle zur neuzeit. T. 2: Vom tode Wolters von Plettenberg bis zum Untergang des Deutschen Ordens in Livland (1535-1561). Bonn: Kulturstiftung der deutshen Vertriebenen 2001. (Historische Forschungen).

Archive of Geosample Information from the Alfred-Wegener-Institut (AWI) Core Repository

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Alfred-Wegener-Institut (AWI) made a one-time contribution to the Index to Marine and Lacustrine Geological Samples (IMLGS) database of metadata describing 1820...

"Kaj" je Frederick Winslow Taylor = “What” is Frederick Winslow Taylor

OpenAIRE

Andrej Markovic

2006-01-01

Raising the issue of Taylor and his scientific management after less than a hundred years seems at first glance to be quite anachronistic. Today we are more likely to find Taylor’s works in antique shops than in the libraries of the schools of management. Has the memory of utilitarian and pragmatic managerial knowledge of a century back faded, or are we in a way ashamed of Taylor, the protagononist of management? How does the research into the origin and nature of management affect the effici...

Rayleigh-Taylor mixing in supernova experiments

International Nuclear Information System (INIS)

Swisher, N. C.; Abarzhi, S. I.; Kuranz, C. C.; Arnett, D.; Hurricane, O.; Remington, B. A.; Robey, H. F.

2015-01-01

We report a scrupulous analysis of data in supernova experiments that are conducted at high power laser facilities in order to study core-collapse supernova SN1987A. Parameters of the experimental system are properly scaled to investigate the interaction of a blast-wave with helium-hydrogen interface, and the induced Rayleigh-Taylor instability and Rayleigh-Taylor mixing of the denser and lighter fluids with time-dependent acceleration. We analyze all available experimental images of the Rayleigh-Taylor flow in supernova experiments and measure delicate features of the interfacial dynamics. A new scaling is identified for calibration of experimental data to enable their accurate analysis and comparisons. By properly accounting for the imprint of the experimental conditions, the data set size and statistics are substantially increased. New theoretical solutions are reported to describe asymptotic dynamics of Rayleigh-Taylor flow with time-dependent acceleration by applying theoretical analysis that considers symmetries and momentum transport. Good qualitative and quantitative agreement is achieved of the experimental data with the theory and simulations. Our study indicates that in supernova experiments Rayleigh-Taylor flow is in the mixing regime, the interface amplitude contributes substantially to the characteristic length scale for energy dissipation; Rayleigh-Taylor mixing keeps order

Kuidas Alfred Adler läks tülli Sigmund Freudiga / Aivar Kull

Index Scriptorium Estoniae

Kull, Aivar, 1955-

1996-01-01

Arvustus: Adler, Alfred. Inimesetundmine : Inimeste iseloomude peategurid ja nende areng / Tlk. Debora Hint. 2.tr. Tln. : Kupar, 1995. Vaata ka: Kull, Aivar. Kulli pilk. - Tartu : Ilmamaa, 2005, lk. 97-100

Towards an Ecology of Participation: Process Philosophy and Co-Creation of Higher Education Curricula

Science.gov (United States)

Taylor, Carol A.; Bovill, Catherine

2018-01-01

This article brings together the authors' previous work on co-created curricula (Bovill, 2013a, 2014; Bovill et al., 2011) and on partnership and ethics (Taylor, 2015; Taylor and Robinson, 2014), to develop the concept of co-created curricula as an ecology of participation. In doing so, it deploys Alfred North Whitehead's process philosophy to…

Confessions of a serial entrepreneur: a conversation with Alfred E. Mann. Interview by Molly Joel Coye.

Science.gov (United States)

Mann, Alfred E

2006-01-01

In this wide-ranging interview, Alfred Mann describes the activities of several medical technology enterprises with which he is engaged. Several of them are companies that he formed; one is a nonprofit foundation, the Alfred E. Mann Foundation for Biomedical Engineering, founded to establish research-oriented institutes on a dozen university campuses and support their work in developing marketable innovations. Mann discusses the need to consider the cost implications of technology, in the context of U.S. health system reform, and describes several important innovations that have emerged from his companies over the years.

33 CFR 207.170d - Taylor Creek, navigation lock (S-193) across the entrance to Taylor Creek at Lake Okeechobee...

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Taylor Creek, navigation lock (S-193) across the entrance to Taylor Creek at Lake Okeechobee, Okeechobee, Fla.; use, administration..., DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE NAVIGATION REGULATIONS § 207.170d Taylor Creek, navigation lock...

THE VISIBLE HAND? THE ECONOMICS OF ALFRED CHANDLER

Directory of Open Access Journals (Sweden)

Don Matthews

2000-01-01

Full Text Available In his great work The Visible Hand: The Managerial Revolution in American Business, Alfred Chandler argues that the modern managerial enterprise replaced the invisible hand of the market in coordinating the activities and allocating the resources of the U.S. economy. But Chandler’s view of the invisible hand of the market is much too narrow. The modern managerial enterprise is not a substitute for the invisible hand of the market but an integral part of it. The Visible Hand is actually a history of the invisible hand of the market.

Spanish contribution in the design of the Alfred Reactor inside the ESNII+ Project

Energy Technology Data Exchange (ETDEWEB)

Romojaro, P.; García-Herranz, N.; Álvarez-Velarde, F.; López, D.

2015-07-01

Significant efforts are being devoted in order to boost R&D on advanced nuclear reactors due to their sustainability and improved safety characteristics. The main drawbacks for the industrial deployment of a Lead-cooled Fast Reactor (LFR) are the lack of operational experience and the technological uncertainties. In order to measure the robustness of the design and improve the safety characteristics of the ALFRED reactor -the demonstration reactor of the European LFR technology- a detailed analysis is envisaged within the EU FP7 ESNII+ project (project to support the European Sustainable Industrial Initiative) (ESNII+, 2013). One key research goal for ALFRED is the demonstration of favourable transient behaviour under accident conditions. Such behaviour depends primarily on the reactivity coefficients of the core. For evaluation of those coefficients, computational tools capable of providing results with a high level of accuracy are available. But the results will be affected by different sources of uncertainty, such as uncertainties on the engineering design, on the nuclear data, model uncertainties, etc. The objective of this work is to perform a sensitivity/uncertainty analysis of ALFRED reactor to assess the impact on the core reactivity of the uncertainties in nuclear data as well as the uncertainties in geometrical tolerances. This will allow having an exhaustive picture of their influence on the core performance, identifying key parameters and proposing specific R&D actions to achieve an improved safety level. (Author)

76 FR 76689 - Cibola National Forest, Mount Taylor Ranger District, NM, Mount Taylor Combined Exploratory Drilling

Science.gov (United States)

2011-12-08

... National Forest, Mount Taylor Ranger District, NM, Mount Taylor Combined Exploratory Drilling AGENCY... proposed action is to approve two Plans of Operations for exploratory uranium drilling on the Cibola... San Mateo. In total, there are up to 279 drill holes that would be drilled over a period not to exceed...

Cuidar em oncologia na perspectiva de Alfred Schütz Cuidado en oncología segundo Alfred Schütz Oncological care according Alfred Schütz

Directory of Open Access Journals (Sweden)

Regina Célia Popim

2005-10-01

Full Text Available O estudo foi realizado com enfermeiros oncológicos em seu cotidiano de trabalho. O objetivo foi compreender a ação subjetiva desses profissionais a partir de sua relação enfermeiro-doente. O referencial fenomenológico, fundamentado nas idéias de Alfred Schütz, possibilitou essa compreensão. Diante de uma questão orientadora: o que significa para você cuidar em oncologia? descreva para mim, foram obtidos depoimentos, os quais, depois de analisados, permitiram chegar ao típico da ação do cuidador enfermeiro neste cotidiano. O estudo revelou que cuidar em oncologia implica em lidar com o humano em situação de fragilidade; requer uma relação de afetividade; é um cuidado que traz consigo a gênese do desgaste profissional. O cuidado em oncologia reveste-se de grande complexidade, requerendo do profissional uma competência que vai para além da esfera técnico-científica. Nesse sentido, o enfermeiro necessita buscar por estratégias que lhe possibilitem o enfrentamento do desgaste a que é submetido em seu trabalho.El estudio fue realizado con enfermeros oncológicos en su cotidiano de trabajo. El objetivo fue comprender la acción subjetiva de esos profesionales desde la relación enfermero-enfermo. El referencial fenomenológico, fundamentado en las ideas de Alfred Schütz, posibilitó esa comprensión. Delante de una cuestión orientadora: ¿qué significa para usted el cuidado en oncología? Descríbame, se obtuvo declaraciones que, tras análisis, permitieron llegar a lo que es típico en la acción cotidiana del cuidador enfermero. El estudio reveló que cuidar en oncología implica tratar con el ser humano en situación de fragilidad; requiere una relación de afectividad; es un cuidado que trae consigo la génesis del desgaste profesional. El cuidado en oncología se reviste de gran complejidad y requiere del profesional una competencia que va más allá de la esfera técnico-científica. En ese sentido, el enfermero

Alfred Bentz - Erdölgeologe in schwieriger Zeit, 1938-1947

Science.gov (United States)

Seibold, E.; Seibold, I.

2002-12-01

Alfred Bentz was the leading oil geologist in Germany during the Third Reich, the World War II and thereafter. His relevant activities are treated here mainly on the base of documents in the Geologenarchiv Freiburg. In spite of his prominent position during the Nazi Regime he can obviously not be blamed for personal guilt. As a loyal civil servant he was embedded in the tragic German fate in these years.

"Kaj" je Frederick Winslow Taylor = “What” is Frederick Winslow Taylor

Directory of Open Access Journals (Sweden)

Andrej Markovic

2006-06-01

Full Text Available Raising the issue of Taylor and his scientific management after less than a hundred years seems at first glance to be quite anachronistic. Today we are more likely to find Taylor’s works in antique shops than in the libraries of the schools of management. Has the memory of utilitarian and pragmatic managerial knowledge of a century back faded, or are we in a way ashamed of Taylor, the protagononist of management? How does the research into the origin and nature of management affect the efficiency of a particular manager, which seems to be the objective of management education? What is the difference between Taylor's management and contemporary management? Is it merely less scientific in approach? And where is modern management developing, if no longer in the field of exact science? And where do key notions of contemporary management, like ‘mission’ and ‘vision’ belong? Has management since its beginings proved to be only knowledge for managing organizations, or does it go beyond that? In a brief analysis of Taylor’s scientific management the author of the article tries to answer the above mentioned questions. Some of the questions are, however, only touched upon, awaiting an answer in the future.

33 CFR 117.987 - Taylor Bayou.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Taylor Bayou. 117.987 Section 117.987 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Texas § 117.987 Taylor Bayou. The draws of the Union Pacific...

O salário na obra de Frederick Winslow Taylor Frederick Winslow Taylor's oeuvre: an analysis of wages

Directory of Open Access Journals (Sweden)

Victor Paulo Gomes da Silva

2011-08-01

Full Text Available O presente artigo analisa e explica a perspectiva de Frederick Winslow Taylor sobre o salário, tal como enunciada em suas duas grandes obras: Shop management (1903 e Principles of scientific management (1911. A primeira parte consubstancia-se na apresentação de aspectos econômicos relevantes que caracterizaram o tempo em que ele viveu e o quanto influenciaram suas obras. Na segunda parte, é efetuada uma análise da forma como o salário é apresentado nas duas obras de F. W. Taylor. O artigo termina com um comentário sobre as obras supracitadas no que se refere à perspectiva taylorista do salário.This paper analyses and explains Frederick Winslow Taylor's perspective on wages, as it is presented in his main literary works: Shop management (1903 and Principles of scientific management (1911. The first part presents the main economic aspects that characterized his lifetime, which undoubtedly influenced his literary works. The second part analyses F. W. Taylor's two main books in which the author's perspective about wages is discussed. The paper concludes with a critical view of F. W. Taylor's view on wages.

Assessment of the implementation risks for ALFRED demonstrator

International Nuclear Information System (INIS)

Constantin, M.; Diaconu, D.

2016-01-01

The risks related to the implementation of ALFRED demonstrator in Romania are discussed. The assessment is based on the risk matrix approach. Two groups of experts were used in the investigation: participants in FP7 ARCADIA projects and members of the FALCON consortium. The results consist of the hierarchy of the risks obtained based on the appreciations of the two groups. They are comparatively presented and discussed in terms of the identified critical risks and possible measures for prevention and mitigation. Additionally, some elements derived from the experience of similar project such as SUSEN and ELI-NP are discussed. (authors)

33 CFR 117.335 - Taylor Creek.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Taylor Creek. 117.335 Section 117.335 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.335 Taylor Creek. The draw of US441 bridge, mile 0...

The European Lead Fast Reactor Strategy and the Roadmap for the Demonstrator ALFRED

International Nuclear Information System (INIS)

Alemberti, A.; De Bruyn, D.; Grasso, G.; Mansani, L.; Mattioli, D.; Roelofs, F.

2013-01-01

Expected impacts: → To ensure that nuclear energy remains a long-term contributor to a low carbon economy it is necessary to increase its sustainability through demonstrating the technical, industrial and economic viability of Gen IV fast nuclear reactors; → With the construction and operation of MYRRHA and ALFRED, Europe will be in an excellent position to secure the development of a safe, sustainable and competitive fast nuclear technology; → ALFRED Demonstrator Roadmap will: • play a key role by involving European industry and maintaining and developing European leadership in nuclear technologies worldwide; • allow to investigate and address the main technological issues that can be implemented in the LFR prototype (2035); • make possible commercial deployment, by the European industry, of these technologies by 2050 and beyond; • contribute significantly to the development of a sustainable and secure energy supply for Europe from the second half of this century onwards

A spherical Taylor-Couette dynamo

Science.gov (United States)

Marcotte, Florence; Gissinger, Christophe

2016-04-01

We present a new scenario for magnetic field amplification in the planetary interiors where an electrically conducting fluid is confined in a differentially rotating, spherical shell (spherical Couette flow) with thin aspect-ratio. When the angular momentum sufficiently decreases outwards, a primary hydrodynamic instability is widely known to develop in the equatorial region, characterized by pairs of counter-rotating, axisymmetric toroidal vortices (Taylor vortices) similar to those observed in cylindrical Couette flow. We characterize the subcritical dynamo bifurcation due to this spherical Taylor-Couette flow and study its evolution as the flow successively breaks into wavy and turbulent Taylor vortices for increasing Reynolds number. We show that the critical magnetic Reynolds number seems to reach a constant value as the Reynolds number is gradually increased. The role of global rotation on the dynamo threshold and the implications for planetary interiors are finally discussed.

String-theoretic deformation of the Parke-Taylor factor

Science.gov (United States)

Mizera, Sebastian; Zhang, Guojun

2017-09-01

Scattering amplitudes in a range of quantum field theories can be computed using the Cachazo-He-Yuan (CHY) formalism. In theories with color ordering, the key ingredient is the so-called Parke-Taylor factor. In this paper we give a fully SL (2 ,C )-covariant definition and study the properties of a new integrand called the "string Parke-Taylor" factor. It has an α' expansion whose leading coefficient is the field-theoretic Parke-Taylor factor. Its main application is that it leads to a CHY formulation of open string tree-level amplitudes. In fact, the definition of the string Parke-Taylor factor was motivated by trying to extend the compact formula for the first α' correction found by He and Zhang, while the main ingredient in its definition is a determinant of a matrix introduced in the context of string theory by Stieberger and Taylor.

O estilo em Alfred Döblin

Directory of Open Access Journals (Sweden)

Elcio Loureiro Cornelsen

2010-01-01

Full Text Available O objetivo do presente artigo é apresentar alguns aspectos teóricos postulados pelo escritor alemão Alfred Döblin em seus ensaios ao desenvolver sua própria concepção da obra épica na "era da técnica" à luz de questões estilísticas, propondo conceitos como "estilo cinematográfico", "despersonalização", "fantasia factual" e "fantasia cinética". Para uma delimitação conceitual em relação à noção de "estilo", serão tomadas por base as considerações de Antoine Compagnon, postuladas na obra O demônio da teoria (1999, bem como as reflexões de Walter Benjamin, presentes na resenha "A crise do romance" (1930 e no ensaio "O narrador" (1936.

Alfred. První opera Antonína Dvořáka se vrací

Czech Academy of Sciences Publication Activity Database

Kratochvílová, Markéta

2014-01-01

Roč. 19, č. 3 (2014), s. 6-7 Institutional support: RVO:68378076 Keywords : Gerd Albrecht * Adolf Heller * Karl Theodor Körner * opera * Antonín Dvořák * Alfred Subject RIV: AL - Art, Architecture, Cultural Heritage

Contrasting Views of Emotion in Learning: Alfred North Whitehead and Jerome Bruner

Science.gov (United States)

Woodhouse, Howard

2017-01-01

The article analyzes contrasting theories about the role of emotion in learning proposed by Alfred North Whitehead and Jerome Bruner. I argue that Whitehead's account of experience and emotion in his educational philosophy is best understood in the context of the philosophy of organism. Here he takes issue with the empiricists' view that sensa are…

Alfred Russel Wallace’s record of his consignments to Samuel Stevens, 1854-1861

NARCIS (Netherlands)

Baker, D.B.

2001-01-01

An annotated facsimile of those pages of Alfred Russel Wallace’s notebook recording his consignments from the Malay Archipelago to his London agent, Samuel Stevens, is provided. Records of individual consignments are linked with the stages of Wallace’s and Charles Allen’s itineraries to which they

Non-vanishing of Taylor coefficients and Poincaré series

DEFF Research Database (Denmark)

O'Sullivan, C.; Risager, Morten S.

2013-01-01

We prove recursive formulas for the Taylor coefficients of cusp forms, such as Ramanujan's Delta function, at points in the upper half-plane. This allows us to show the non-vanishing of all Taylor coefficients of Delta at CM points of small discriminant as well as the non-vanishing of certain...... Poincaré series. At a "generic" point, all Taylor coefficients are shown to be non-zero. Some conjectures on the Taylor coefficients of Delta at CM points are stated....

Taylor series maps and their domain of convergence

International Nuclear Information System (INIS)

Abell, D.T.; Dragt, A.J.

1992-01-01

This paper tries to make clear what limits the validity of a Taylor series map, and how. We describe the concept of a transfer map and quote some theorems that justify not only their existence but also their advantages. Then, we describe the Taylor series representation for transfer maps. Following that, we attempt to elucidate some of the basic theorems from the theory of functions of one and several complex variables. This material forms the core of our understanding of what limits the domain of convergence of Taylor series maps. Lastly, we use the concrete example of a simple anharmonic oscillator to illustrate how the theorems from several complex variable theory affect the domain convergence of Taylor series maps. There we describe the singularities of the anharmonic oscillator in the complex planes of the initial conditions, show how they constrain our use of a Taylor series map, and then discuss our findings

A biography and obituary of Alfred Traverse (1925–2015)

OpenAIRE

Riding, James B.; Chaloner FRS, William G.; Farley, Martin B.; Rich, Fredrick J.; Strother, Paul K.

2016-01-01

Professor Alfred (‘Al’) Traverse passed away following a long illness at 90 years of age on September 15th 2015 at Juniper Village, State College, Pennsylvania, USA. With his death, the twin sciences of palaeobotany and palynology have lost one of their most influential and productive of practitioners and teachers. He had a stellar student career, was a coal petrologist, an industrial palynologist and held parallel positions in the Episcopal (Anglican) church. However he is principally define...

Taylorism and the Logic of Learning Outcomes

Science.gov (United States)

Stoller, Aaron

2015-01-01

This essay examines the shared philosophical foundations of Fredrick W. Taylor's scientific management principles and the contemporary learning outcomes movement (LOM). It analyses the shared philosophical ground between the focal point of Taylor's system--"the task"--and the conceptualization and deployment of "learning…

‘None but Ourselves Can Free Our Minds’: Review of "A Community Life: Memoirs of Alfred M. Sears"

Directory of Open Access Journals (Sweden)

Ann Victoria Dean

2017-07-01

Full Text Available Review of A Community Life: Memoirs of Alfred M. Sears: A Redemption Story from Reform School to Attorney General and Minister of Education of the Bahamas, Alfred M. Sears. I-EASE Publishack, 2017. ISBN 978-978-8201-14-4 This emotionally charged testimonial to life in the historical colonial and postcolonial Bahamas is a deeply politicized story of personal and political redemption built on Alfred Sears’ decades-long commitment to literacy and education, to the value of family and community and to the practice of speaking truth to power. Sears argues that both the health of Bahamian society and the sovereignty of the nation are dependent on its citizens being able to think for themselves and for that to happen, it is imperative to root out the legacies of colonialism. He makes recommendations for altering the Bahamian Constitution and thematically addresses concerns about government corruption, transparency, and accountability; partisan polarization; the Bahamian politic as a system of patronage and clientelism; the need for constitutional reform; political campaign finance reform; sustained economic development and participatory regionalism.

The Life and Legacy of G. I. Taylor

Science.gov (United States)

Batchelor, G. K.

1996-07-01

G.I. Taylor, one of the most distinguished physical scientists of this century, used his deep insight and originality to increase our understanding of phenomena such as the turbulent flow of fluids. His interest in the science of fluid flow was not confined to theory; he was one of the early pioneers of aeronautics, and designed a new type of anchor that was inspired by his passion for sailing. Taylor spent most of his working life in the Cavendish Laboratory in Cambridge, where he investigated the mechanics of fluid and solid materials; his discoveries and ideas have had application throughout mechanical, civil, and chemical engineering, meteorology, oceanography and materials science. He was also a noted research leader, and his group in Cambridge became one of the most productive centers for the study of fluid mechanics. How was Taylor able to be innovative in so many different ways? This interesting and unusual biography helps answer that question. Professor Batchelor, himself a student and close collaborator of Taylor, is ideally placed to describe Taylor's life, achievements and background. He does so without introducing any mathematical details, making this book enjoyable reading for a wide range of people--and especially those whose own interests have brought them into contact with the legacy of Taylor.

Educar na autenticidade em Charles Taylor = Educating in the authenticity in Charles Taylor

Directory of Open Access Journals (Sweden)

Foschiera, Rogério

2009-01-01

Full Text Available Analiso a perspectiva tayloriana da autencidade através de uma hermenêutica de suas principais obras para propor o significado de educar na autencticidade a partir de Charles Taylor. Com autencidade e ontologia moral Taylor apresenta uma antropologia ancorada na moral e na ontologia. Com autencidade e epistemologia se percebe que a perspectiva da autencidade não exclui o paradigma científico, mas necessita de outros paradigmas, principalmente do hermenêutico. Com autencidade e linguagem evidencio a compreensão de Taylor sobre a natureza da linguagem e o destaque que ele dá á definição de ser humano como "animal portador de logos", bem como o significado e as decorrências da perspectiva expressivista. Duas políticas: a da igualdade de direitos de todos e a do reconhecimento das diferenças estão integradas na perspectiva tayloriana da autencidade. Necessariamente, o ser humano, para ser autêntico, estará em constante referência a horizontes de sentido que transcendem o indivíduo, é o que apresento com autencidade e transcendência

The Alfred Nobel rocket camera. An early aerial photography attempt

Science.gov (United States)

Ingemar Skoog, A.

2010-02-01

Alfred Nobel (1833-1896), mainly known for his invention of dynamite and the creation of the Nobel Prices, was an engineer and inventor active in many fields of science and engineering, e.g. chemistry, medicine, mechanics, metallurgy, optics, armoury and rocketry. Amongst his inventions in rocketry was the smokeless solid propellant ballistite (i.e. cordite) patented for the first time in 1887. As a very wealthy person he actively supported many Swedish inventors in their work. One of them was W.T. Unge, who was devoted to the development of rockets and their applications. Nobel and Unge had several rocket patents together and also jointly worked on various rocket applications. In mid-1896 Nobel applied for patents in England and France for "An Improved Mode of Obtaining Photographic Maps and Earth or Ground Measurements" using a photographic camera carried by a "…balloon, rocket or missile…". During the remaining of 1896 the mechanical design of the camera mechanism was pursued and cameras manufactured. In April 1897 (after the death of Alfred Nobel) the first aerial photos were taken by these cameras. These photos might be the first documented aerial photos taken by a rocket borne camera. Cameras and photos from 1897 have been preserved. Nobel did not only develop the rocket borne camera but also proposed methods on how to use the photographs taken for ground measurements and preparing maps.

On truncated Taylor series and the position of their spurious zeros

DEFF Research Database (Denmark)

Christiansen, Søren; Madsen, Per A.

2006-01-01

A truncated Taylor series, or a Taylor polynomial, which may appear when treating the motion of gravity water waves, is obtained by truncating an infinite Taylor series for a complex, analytical function. For such a polynomial the position of the complex zeros is considered in case the Taylor...

Taylor's series method for solving the nonlinear point kinetics equations

International Nuclear Information System (INIS)

Nahla, Abdallah A.

2011-01-01

Highlights: → Taylor's series method for nonlinear point kinetics equations is applied. → The general order of derivatives are derived for this system. → Stability of Taylor's series method is studied. → Taylor's series method is A-stable for negative reactivity. → Taylor's series method is an accurate computational technique. - Abstract: Taylor's series method for solving the point reactor kinetics equations with multi-group of delayed neutrons in the presence of Newtonian temperature feedback reactivity is applied and programmed by FORTRAN. This system is the couples of the stiff nonlinear ordinary differential equations. This numerical method is based on the different order derivatives of the neutron density, the precursor concentrations of i-group of delayed neutrons and the reactivity. The r th order of derivatives are derived. The stability of Taylor's series method is discussed. Three sets of applications: step, ramp and temperature feedback reactivities are computed. Taylor's series method is an accurate computational technique and stable for negative step, negative ramp and temperature feedback reactivities. This method is useful than the traditional methods for solving the nonlinear point kinetics equations.

76 FR 3570 - Proposed Amendment of Class E Airspace; Taylor, AZ

Science.gov (United States)

2011-01-20

...-1189; Airspace Docket No. 10-AWP-19] Proposed Amendment of Class E Airspace; Taylor, AZ AGENCY: Federal... proposes to modify Class E airspace at Taylor Airport, Taylor, AZ. Controlled airspace is necessary to accommodate aircraft using the CAMBO One Departure Area Navigation (RNAV) out of Taylor Airport. The FAA is...

Application of Taylor-Series Integration to Reentry Problems with Wind

NARCIS (Netherlands)

Bergsma, Michiel; Mooij, E.

2016-01-01

Taylor-series integration is a numerical integration technique that computes the Taylor series of state variables using recurrence relations and uses this series to propagate the state in time. A Taylor-series integration reentry integrator is developed and compared with the fifth-order

Preface to The Diary of Vaslav Nijinsky by Alfred Adler, MD.

Science.gov (United States)

Ansbacher, H L

1981-07-01

This is a previously unpublished work by Alfred Adler that was written in 1936 as a preface to The Diary of Vaslav Nijinsky. A theory of schizophrenia is described in which characteristic prepsychotic features, especially lack of social interest and oversensitivity to real and imagined slights, lead to increasing irrationalism and preoccupation with grandiose ideas. The establishment of a cooperative therapeutic relationship and the instilling of hope are presented as central factors for successful treatment.

Alfred Lee Loomis - last great amateur of science

International Nuclear Information System (INIS)

Alvarex, L.W.

1983-01-01

Alfred Loomis may well be remembered as the last of the great amateurs of science. He had distinguished careers as a lawyer, as an Army officer and as an investment banker before he turned his full energies to the pursuit of scientific knowledge, first in the field of physics and later as a biologist. By any measure that can be employed, he was one of the most influential physical scientists of this century: he was elected to the National Academy when he was 53 years old; he received many honorary degrees from prestigious universities; and he played a crucial role as director of all NDRC-OSRD radar research in World War II

Generalization of the Taylor Principle

International Nuclear Information System (INIS)

Jensen, T.H.

1986-01-01

The usual Taylor Principle can in general only be applied when the system is closed. This paper describes a suggestion of a generalization to cover the case that the plasma is surrounded by a conducting shell with narrow gaps where the external circuits connected to the gaps consist of just inductors. The suggested constraint of the generalized Taylor Principle is that no helicity is absorbed by the plasma. The usual assumption that the stable Taylor Equilibrium is that for which the magnetic energy in the plasma region as well as in the external inductors is minimized subject to the above constraint, again leads to a unique configuration. It is found that this configuration is dependent upon the inductances of the external inductors. For the sake of conceptual simplicity, consider a closed shell of conducting material. The interior of the shell may be divided into various compartments only corrected through narrow gaps in the conducting walls between these compartments. They assume plasma present in only one of the compartments; the neighboring compartments represent the external inductors connected across the gaps of the plasma compartment

The New Taylorism: Hacking at the Philosophy of the University's End

Science.gov (United States)

Goodman, Robin Truth

2012-01-01

This article looks at the critical writings of Mark C. Taylor. It suggests that Mark C. Taylor is rewriting a global imaginary devoid of the kind of citizenship that Henry Giroux claims as the basis for public education. Instead, Taylor wants to see the university take shape as profit-generating. According to Taylor, in lieu of learning to take…

Periodic Reactions: The Early Works of William C. Bray and Alfred J. Lotka

Science.gov (United States)

Cervellati, Rinaldo; Greco, Emanuela

2017-01-01

Oscillating chemical reactions in the homogeneous phase have been studied intensively only since the mid-1960s, but they were known since 1920, having as forerunners the chemist William C. Bray and an "atypical" chemist Alfred J. Lotka. This contribution is the result of a careful reading of their literature and patient research into…

Dynamic Transition and Pattern Formation in Taylor Problem

Institute of Scientific and Technical Information of China (English)

Tian MA; Shouhong WANG

2010-01-01

The main objective of this article is to study both dynamic and structural transitions of the Taylor-Couette flow,by using the dynamic transition theory and geometric theory of incompressible flows developed recently by the authors.In particular,it is shown that as the Taylor number crosses the critical number,the system undergoes either a continuous or a jump dynamic transition,dictated by the sign of a computable,nondimensional parameter R.In addition,it is also shown that the new transition states have the Taylor vortex type of flow structure,which is structurally stable.

76 FR 18378 - Amendment of Class E Airspace; Taylor, AZ

Science.gov (United States)

2011-04-04

...-1189; Airspace Docket No. 10-AWP-19] Amendment of Class E Airspace; Taylor, AZ AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action will amend Class E airspace at Taylor Airport, Taylor, AZ, to accommodate aircraft using the CAMBO One Departure, and the Area Navigation (RNAV...

Fluid Mechanics of Taylor Bubbles and Slug Flows in Vertical Channels

International Nuclear Information System (INIS)

Anglart, Henryk; Podowski, Michael Z.

2002-01-01

Fluid mechanics of Taylor bubbles and slug flows is investigated in vertical, circular channels using detailed, three-dimensional computational fluid dynamics simulations. The Volume of Fluid model with the interface-sharpening algorithm, implemented in the commercial CFX4 code, is used to predict the shape and velocity of Taylor bubbles moving along a vertical channel. Several cases are investigated, including both a single Taylor bubble and a train of bubbles rising in water. It is shown that the potential flow solution underpredicts the water film thickness around Taylor bubbles. Furthermore, the computer simulations that are performed reveal the importance of properly modeling the three-dimensional nature of phenomena governing the motion of Taylor bubbles. Based on the present results, a new formula for the evaluation of bubble shape is derived. Both the shape of Taylor bubbles and the bubble rise velocity predicted by the proposed model agree well with experimental observations. Furthermore, the present model shows good promise in predicting the coalescence of Taylor bubbles

The significance of Alfred Adler for the concept of narcissism.

Science.gov (United States)

Ansbacher, H L

1985-02-01

Alfred Adler's significance for the concept of narcissism is presented with reference to four aspects: 1) Adler's theory of masculine protest was evidently a factor influencing Freud to turn toward the phenomenon of narcissism. 2) Present-day understanding of narcissism shows remarkable similarity to Adler's views on psychodynamics and neurotic egocentricity. 3) Some contemporary criticisms of Freud's theory of narcissism are very similar to Adler's criticism. 4) Adler's theory of social interest permits subsumption of narcissism under lack of social interest rather than acceptance of it as an expression of innate socially negative tendencies.

The Rayleigh-Taylor instability in the spherical pinch

International Nuclear Information System (INIS)

Chen, H.B.; Hilko, B.; Panarella, E.

1994-01-01

The spherical pinch (SP) concept is an outgrowth of the inertial confinement model (ICF). Unlike the ICF where instabilities, especially the Rayleigh-Taylor instability, have been studied extensively, the instability study of the spherical pinch has just begun. The Raleigh-Taylor instability is investigated for the first time in the SP in the present work. By using the simple condition for the Rayleigh-Taylor instability ∇p · ∇p < O (density and pressure gradients have opposite direction), we have qualitatively identified the regions for development of instabilities in the SP. It is found that the explosion phase (central discharge) is stable and instabilities take place in the imploding phase. However, the growth rate for the instability is not in exponential form, and the appearance of the Rayleigh-Taylor instability does not prevent the main shock wave from converging to the center of the sphere

Jean-Alfred Fournier - the founder of the European venereology and dermatology (on the one hundredth death anniversary

Directory of Open Access Journals (Sweden)

O. A. Kisteneva

2014-01-01

Full Text Available The article presents a life story of a great French dermatologist and venereologist, one of the founders of the theory of syphilis Jean-Alfred Fournier (1832-1914. It provides data on the published works by Jean-Alfred Fournier, some of which earned him a doctoral degree. It also provides data on Fournier’s election as a member of the French Academy of Medicine in 1879 as well as on the founding of the French Society of Dermatology and Syphiligraphy by Fournier and other French dermatologists in 1889. The article defines the contribution made by Fournier to the development of venereology and practical medicine in the second half of the 19th century and early 20th century.

G.I. Taylor and the Trinity Test

Science.gov (United States)

Deakin, Michael A. B.

2011-01-01

The story is often told of the calculation by G.I. Taylor of the yield of the first ever atomic bomb exploded in New Mexico in 1945. It has indeed become a staple of the classroom whenever dimensional analysis is taught. However, while it is true that Taylor succeeded in calculating this figure at a time when it was still classified, most versions…

Effects of shock waves on Rayleigh-Taylor instability

International Nuclear Information System (INIS)

Zhang Yongtao; Shu Chiwang; Zhou Ye

2006-01-01

A numerical simulation of two-dimensional compressible Navier-Stokes equations using a high-order weighted essentially nonoscillatory finite difference shock capturing scheme is carried out in this paper, to study the effect of shock waves on the development of Rayleigh-Taylor instability. Shocks with different Mach numbers are introduced ahead or behind the Rayleigh-Taylor interface, and their effect on the transition to instability is demonstrated and compared. It is observed that shock waves can speed up the transition to instability for the Rayleigh-Taylor interface significantly. Stronger shocks are more effective in this speed-up process

Vertigo, poetry and creed of Alfred Hitchcock's cinema

Directory of Open Access Journals (Sweden)

Rafael J. Pascual

2011-09-01

Full Text Available In this article we analyse the film Vertigo -undoubtedly one of the North-American film di- rector Alfred Hitchcock’s masterpiece- as an audiovisual poem we could identify with such a characteristic and defining name as film-poetry. We will try to show some elements very typical of cinema -the use of the light, colour, and music, the aesthetic treatment of image and the camera movement- they all aspects that in- fluence -as well as does plot- the rhythm, form and content in the same way as a poem does, in order to place cinema at the same level as poetry. We will try to describe in a very essential way the relations between cinema and arts such as music, painting and literature.

Why Community Works: The Use of Alfred Adler's Individual Psychology as a Foundational Theory.

Science.gov (United States)

Glenn, Robert K.; Keith, Edwin M.

2002-01-01

Asserts that the Individual Psychology of Alfred Adler should be used as a foundational theory for student affairs work. The success of community building programs is explained and the concepts of Individual Psychology are summarized. Also asserts that the current drive to develop programs to develop community on college campuses is firmly rooted…

“What” is Frederick Winslow Taylor

OpenAIRE

Andrej Markovic

2006-01-01

Raising the issue of Taylor and his scientific management after less than a hundred years seems at first glance to be quite anachronistic. Today we are more likely to find Taylor’s works in antique shops than in the libraries of the schools of management. Has the memory of utilitarian and pragmatic managerial knowledge of a century back faded, or are we in a way ashamed of Taylor, the protagononist of management? How does the research into the origin and nature of management affect the effici...

Bright and durable field emission source derived from refractory taylor cones

Science.gov (United States)

Hirsch, Gregory

2016-12-20

A method of producing field emitters having improved brightness and durability relying on the creation of a liquid Taylor cone from electrically conductive materials having high melting points. The method calls for melting the end of a wire substrate with a focused laser beam, while imposing a high positive potential on the material. The resulting molten Taylor cone is subsequently rapidly quenched by cessation of the laser power. Rapid quenching is facilitated in large part by radiative cooling, resulting in structures having characteristics closely matching that of the original liquid Taylor cone. Frozen Taylor cones thus obtained yield desirable tip end forms for field emission sources in electron beam applications. Regeneration of the frozen Taylor cones in-situ is readily accomplished by repeating the initial formation procedures. The high temperature liquid Taylor cones can also be employed as bright ion sources with chemical elements previously considered impractical to implement.

Experiments on the Taylor system with an axial flow

International Nuclear Information System (INIS)

Tsameret, Avraham.

1993-02-01

This work is an experimental study of the Taylor system with a superimposed axial flow. The convective and absolute instability lines which are associated with the propagating Taylor vortices are measured. A quantitative agreement is found with the theoretical predictions. Noise-sustained structures are found to exist in the convectively unstable region, above a critical value of the through flow. These structures are propagating Taylor vortices that are characterized by a noisy power spectrum and irregular temporal dynamics of velocity amplitude. At the absolute instability line the power spectrum of the propagating Taylor vortices exhibits transition to a sharp peak, and the amplitude of the propagating Taylor vortices becomes stationary. The mechanism that generates the noise-sustained structures is identified with a process of permanent amplification of noise that is generated mainly near the inlet boundary. The intrinsic noise in the system is studied. This study is motivated by the question of whether the noise which generates the noise-sustained structures is thermal. The intensity of the intrinsic noise is estimated by several methods, which includes a comparison of data with numerical simulations of the amplitude equation with a noise term. It is found that the intrinsic noise is not thermal, although its intensity reaches the thermal noise level at small through-flow velocities. Novel states are manifested in the system as a result of interaction between the propagating Taylor vortices and spiral modes. These states are studied and their spatial and temporal properties are analyzed. (author)

Centrifugally Driven Rayleigh-Taylor Instability

Science.gov (United States)

Scase, Matthew; Hill, Richard

2017-11-01

The instability that develops at the interface between two fluids of differing density due to the rapid rotation of the system may be considered as a limit of high-rotation rate Rayleigh-Taylor instability. Previously the authors have considered the effect of rotation on a gravitationally dominated Rayleigh-Taylor instability and have shown that some growth modes of instability may be suppressed completely by the stabilizing effect of rotation (Phys. Rev. Fluids 2:024801, Sci. Rep. 5:11706). Here we consider the case of very high rotation rates and a negligible gravitational field. The initial condition is of a dense inner cylinder of fluid surrounded by a lighter layer of fluid. As the system is rotated about the generating axis of the cylinder, the dense inner fluid moves away from the axis and the familiar bubbles and spikes of Rayleigh-Taylor instability develop at the interface. The system may be thought of as a ``fluid-fluid centrifuge''. By developing a model based on an Orr-Sommerfeld equation, we consider the effects of viscosity, surface tension and interface diffusion on the growth rate and modes of instability. We show that under particular circumstances some modes may be stabilized. School of Mathematical Sciences.

Animating Nested Taylor Polynomials to Approximate a Function

Science.gov (United States)

Mazzone, Eric F.; Piper, Bruce R.

2010-01-01

The way that Taylor polynomials approximate functions can be demonstrated by moving the center point while keeping the degree fixed. These animations are particularly nice when the Taylor polynomials do not intersect and form a nested family. We prove a result that shows when this nesting occurs. The animations can be shown in class or…

[Alfred Adler and the psychology of aesthetic surgery in the United States].

Science.gov (United States)

Gilman, S L

2002-01-01

The quest for a psychological theory to explain the effects of aesthetic surgery reached its high point in the 1920s with the adoption of Alfred Adler's theory of the inferiority complex. The basis for this theory was Adler's early work in the psychological response of the body to disease and "degeneration". Aesthetic surgeons sought out the Adlerian model rather than a Freudian one as purely psychological while its roots, and their own theories, were clearly somatic in origin.

Instabilities with polyacrylamide solution in small and large aspect ratios Taylor-Couette systems

International Nuclear Information System (INIS)

Smieszek, M; Egbers, C; Crumeyrolle, O; Mutabazi, I

2008-01-01

We have investigated the stability of viscoelastic polyacrylamide solution in Taylor-Couette system with different aspect ratios. The first instability modes observed in a Taylor-Couette system with Γ = 10 were TVF and WVF, as for Newtonian fluid. At higher Taylor numbers moving vortices occur, a wavy mode with non-stationary vortex size. In the Taylor-Couette system with Γ = 45.9 we note a coexistence of various instability modes. In addition to TVF, counterpropagating waves developed at the transition from the base state flow. At higher Taylor number values Taylor vortices of different sizes occurred. Reduced amplitude Wavy vortex flow has also been observed.

Repainting, modifying, smashing Taylorism

NARCIS (Netherlands)

H.D. Pruijt (Hans)

2000-01-01

textabstractAbstract Survey data show that post-Tayloristic production concepts are not developing to the extent that many researchers had originally expected. It also is inadequate to portray post-Taylorism as a development that is happening, but just slower than expected. This is inadequate

Rayleigh-Taylor instability and mixing in SN 1987A

International Nuclear Information System (INIS)

Ebisuzaki, T.; Shigeyama, T.; Nomoto, K.

1989-01-01

The stability of the supernova ejecta is compared with the Rayleigh-Taylor instability for a realistic model of SN 1987A. A linear analysis indicates that the layers around the composition interface between the hydrogen-rich and helium zones, and become Rayleigh-Taylor unstable between the helium and metal zones. In these layers, the pressure increases outward because of deceleration due to the reverse shock which forms when the blast shock hits the massive hydrogen-rich envelope. On the contrary, the density steeply decreases outward because of the preexisting nuclear burning shell. Then, these layers undergo the Raleigh-Taylor instability because of the opposite signs of the pressure and density gradients. The estimated growth rate is larger than the expansion rate of the supernova. The Rayleigh-Taylor instability near the composition interface is likely to induce mixing, which has been strongly suggested from observations of SN 1987A. 25 refs

Dynamics of helicity transport and Taylor relaxation

International Nuclear Information System (INIS)

Diamond, P.H.; Malkov, M.

2003-01-01

A simple model of the dynamics of Taylor relaxation is derived using symmetry principles alone. No statistical closure approximations are invoked or detailed plasma model properties assumed. Notably, the model predicts several classes of nondiffusive helicity transport phenomena, including traveling nonlinear waves and superdiffusive turbulent pulses. A universal expression for the scaling of the effective magnetic Reynolds number of a system undergoing Taylor relaxation is derived. Some basic properties of intermittency in helicity transport are examined

High Speed Solution of Spacecraft Trajectory Problems Using Taylor Series Integration

Science.gov (United States)

Scott, James R.; Martini, Michael C.

2008-01-01

Taylor series integration is implemented in a spacecraft trajectory analysis code-the Spacecraft N-body Analysis Program (SNAP) - and compared with the code s existing eighth-order Runge-Kutta Fehlberg time integration scheme. Nine trajectory problems, including near Earth, lunar, Mars and Europa missions, are analyzed. Head-to-head comparison at five different error tolerances shows that, on average, Taylor series is faster than Runge-Kutta Fehlberg by a factor of 15.8. Results further show that Taylor series has superior convergence properties. Taylor series integration proves that it can provide rapid, highly accurate solutions to spacecraft trajectory problems.

Vortex formation in Taylor-Couette flow with weakly spatial modulation

International Nuclear Information System (INIS)

Li, Z.; Khayat, R.E.

2002-01-01

The onset of the vortex structure in axisymmetric Taylor-Couette flow with spatially modulated cylinders is examined. The modulation amplitude is assumed to be small for a regular perturbation solution to be sought at small to moderate Taylor numbers. It is found that the presence of a weak modulation of the outer or inner cylinders leads unavoidably to the emergence of steady vortex flow even for a vanishingly small Taylor number. This situation is reminiscent of the onset of an imperfect bifurcation. The vortex structure of the forced TVF is found to have same periodicity when only one cylinder is modulated or the two modulations are commensurate for the Taylor number measured. The vortex structure is quasi-periodic when the two modulations are incommensurate. For a certain Taylor number, there exists a critical wavelength for the presence of the strongest vortex flow when the modulation is in the form of sinusoidal. This critical wavelength tends to the critical value predicted by the linear stability analysis when Ta approaches the supercritical value. (author)

Alfred Russel Wallace and the antivaccination movement in Victorian England.

Science.gov (United States)

Weber, Thomas P

2010-04-01

Alfred Russel Wallace, eminent naturalist and codiscoverer of the principle of natural selection, was a major participant in the antivaccination campaigns in late 19th-century England. Wallace combined social reformism and quantitative arguments to undermine the claims of provaccinationists and had a major impact on the debate. A brief account of Wallace's background, his role in the campaign, and a summary of his quantitative arguments leads to the conclusion that it is unwarranted to portray Victorian antivaccination campaigners in general as irrational and antiscience. Public health policy can benefit from history, but the proper context of the evidence used should always be kept in mind.

ALFRED: An Allele Frequency Database for Microevolutionary Studies

Directory of Open Access Journals (Sweden)

Kenneth K Kidd

2005-01-01

Full Text Available Many kinds of microevolutionary studies require data on multiple polymorphisms in multiple populations. Increasingly, and especially for human populations, multiple research groups collect relevant data and those data are dispersed widely in the literature. ALFRED has been designed to hold data from many sources and make them available over the web. Data are assembled from multiple sources, curated, and entered into the database. Multiple links to other resources are also established by the curators. A variety of search options are available and additional geographic based interfaces are being developed. The database can serve the human anthropologic genetic community by identifying what loci are already typed on many populations thereby helping to focus efforts on a common set of markers. The database can also serve as a model for databases handling similar DNA polymorphism data for other species.

A design of inverse Taylor projectiles using material simulation

International Nuclear Information System (INIS)

Tonks, Michael; Harstad, Eric; Maudlin, Paul; Trujillo, Carl

2008-01-01

The classic Taylor cylinder test, in which a right circular cylinder is projected at a rigid anvil, exploits the inertia of the projectile to access strain rates that are difficult to achieve with more traditional uniaxial testing methods. In this work we present our efforts to design inverse Taylor projectiles, in which a tapered projectile becomes a right circular cylinder after impact, from annealed copper and show that the self-correcting geometry leads to a uniform compressive strain in the radial direction. We design projectiles using finite element simulation and optimization that deform as desired in tests with minor deviations in the deformed geometry due to manufacturing error and uncertainty in the initial velocity. The inverse Taylor projectiles designed in this manner provide a simple means of validating constitutive models. This work is a step towards developing a general method of designing Taylor projectiles that provide stress–strain behavior relevant to particular engineering problems

Techniques for optimizing nanotips derived from frozen taylor cones

Science.gov (United States)

Hirsch, Gregory

2017-12-05

Optimization techniques are disclosed for producing sharp and stable tips/nanotips relying on liquid Taylor cones created from electrically conductive materials with high melting points. A wire substrate of such a material with a preform end in the shape of a regular or concave cone, is first melted with a focused laser beam. Under the influence of a high positive potential, a Taylor cone in a liquid/molten state is formed at that end. The cone is then quenched upon cessation of the laser power, thus freezing the Taylor cone. The tip of the frozen Taylor cone is reheated by the laser to allow its precise localized melting and shaping. Tips thus obtained yield desirable end-forms suitable as electron field emission sources for a variety of applications. In-situ regeneration of the tip is readily accomplished. These tips can also be employed as regenerable bright ion sources using field ionization/desorption of introduced chemical species.

[Studying at École de pharmacie de Lille with Alfred Giard in the XIXth century].

Science.gov (United States)

Guerriaud, Mathieu

2015-06-01

This article describes a pharmacy student's notebook in Lille in the 1870s. The Medical Natural History course is taught by Alfred Mathieu Giard. Following a brief biography of the latter, excerpts of the manuscript are presented, they reveal the extent of scientific knowledge of the late nineteenth century, especially in the field of Parasitology.

PREFACE: The 15th International Couette-Taylor Worskhop

Science.gov (United States)

Mutabazi, Innocent; Crumeyrolle, Olivier

2008-07-01

The 15th International Couette-Taylor Worskhop (ICTW15) was held in Le Havre, France from 9-12 July 2007. This regular international conference started in 1979 in Leeds, UK when the research interest in simple models of fluid flows was revitalized by systematic investigation of Rayleigh-Bénard convection and the Couette-Taylor flow. These two flow systems are good prototypes for the study of the transition to chaos and turbulence in closed flows. The workshop themes have been expanded from the original Couette-Taylor flow to include other centrifugal instabilities (Dean, Görtler, Taylor-Dean), spherical Couette flows, thermal convection instabilities, MHD, nonlinear dynamics and chaos, transition to turbulence, development of numerical and experimental techniques. The impressive longevity of the ICTW is due to the close interaction and fertile exchanges between international research groups from different disciplines: Physics and Astrophysics, Applied Mathematics, Mechanical Engineering, Chemical Engineering. The present workshop was attended by 100 participants, the program included over 83 contributions with 4 plenary lectures, 68 oral communications and 17 posters. The topics include, besides the classical Couette-Taylor flows, the centrifugal flows with longitudinal vortices, the shear flows, the thermal convection in curved geometries, the spherical Couette-Taylor flow, the geophysical flows, the magneto-hydrodynamic effects including the dynamo effect, the complex flows (viscoelasticity, immiscible fluids, bubbles and migration). Selected papers have been processed through the peer review system and are published in this issue of the Journal of Physics: Conference Series. The Workshop has been sponsored by Le Havre University, the Region Council of Haute-Normandie, Le Havre City Council, CNRS (ST2I, GdR-DYCOEC), and the European Space Agency through GEOFLOW program. The French Ministry of Defense (DGA), the Ministry of Foreign Affairs, the Ministry of

DSM-5 and ADHD - an interview with Eric Taylor.

Science.gov (United States)

Taylor, Eric

2013-09-12

In this podcast we talk to Prof Eric Taylor about the changes to the diagnosis of Attention Deficit Hyperactivity Disorder (ADHD) in DSM-5 and how these changes will affect clinical practice. The podcast for this interview is available at: http://www.biomedcentral.com/sites/2999/download/Taylor.mp3.

The prominent absence of Alfred Russel Wallace at the Darwin anniversaries in Germany in 1909, 1959 and 2009.

Science.gov (United States)

Hossfeld, Uwe; Olsson, Lennart

2013-12-01

It is well known that the contribution of Alfred Russell Wallace (1823-1913) to the development of the "Darwinian" principle of natural selection has often been neglected. Here we focus on how the three anniversaries to celebrate the origin of the Darwin-Wallace theory in Germany in 1909, in 1959 in the divided country, as well as in 2009, have represented Charles Robert Darwin's and Alfred Russell Wallace's contributions. We have analyzed books and proceedings volumes related to these anniversaries, and the main result is that Wallace was almost always ignored, or only mentioned in passing. In 1909, Ernst Haeckel gave a talk in Jena, later published under the title The worldview of Darwin and Lamarck (Das Weltbild von Darwin und Lamarck), but not as the Darwin-Wallace concept. Haeckel mentions Wallace only once. In two important proceedings volumes from the 1959 anniversaries, Wallace was ignored. The only fair treatment of Wallace is given in another book, a collection of documents edited by Gerhard Heberer, for which the author selected nine key documents and reprinted excerpts (1959). Three of them were articles by Wallace, including the Sarawak- and Ternate-papers of 1855 and 1858, respectively. An analysis of the dominant themes during the celebrations of 2009 shows that none of the six topics had much to do with Wallace and his work. Thus, the tendency to exclude Alfred Russell Wallace is an international phenomenon, and largely attributable to the "Darwin industry".

Compression of an Accelerated Taylor State in SSX

Science.gov (United States)

Shrock, J. E.; Suen-Lewis, E. M.; Barbano, L. J.; Kaur, M.; Schaffner, D. A.; Brown, M. R.

2017-10-01

In the Swarthmore Spheromak Experiment (SSX), compact toroidal plasmas are launched from a plasma gun and evolve into minimum energy twisted Taylor states. The plumes initially have a velocity 40 km/s, density 0.4 ×1016 cm-3 , and proton temperature 20 eV . After formation, the plumes are accelerated by pulsed pinch coils with rise times τ1 / 4 = (π / 2) √{ LC } less than 1 μ s and currents Ipeak =V0 / Z =V0 /√{ L / C } on the order of 104 A. The accelerated Taylor States are abruptly stagnated in a copper flux conserver, and over the course of t plasma, the other to particle motion parallel to the field. We observe Taylor state compression most in agreement with the parallel equation of state: d / dt (P∥B2 /n3) = 0 . DOE ARPA-E ALPHA Program.

Nonlinear saturation of the Rayleigh endash Taylor instability

International Nuclear Information System (INIS)

Das, A.; Mahajan, S.; Kaw, P.; Sen, A.; Benkadda, S.; Verga, A.

1997-01-01

A detailed numerical simulation of the nonlinear state of the Rayleigh endash Taylor instability has been carried out. There are three distinct phases of evolution where it is governed by the (i) linear effects, (ii) effects arising from the conventional nonlinear terms and (iii) subtle nonlinear effects arising through the coupling terms. During the third phase of evolution, there is a self-consistent generation of shear flow which saturates the Rayleigh endash Taylor instability even in situations (with periodic boundaries) where, in principle, an infinite amount of gravitational energy can be tapped. The Galerkin approximation is presented to provide an understanding of our numerical findings. Last, there is an attempt to provide a comprehensive understanding of the nonlinear state of the Rayleigh endash Taylor instability by comparing and contrasting this work with earlier studies. copyright 1997 American Institute of Physics

On Using Taylor's Hypothesis for Three-Dimensional Mixing Layers

Science.gov (United States)

LeBoeuf, Richard L.; Mehta, Rabindra D.

1995-01-01

In the present study, errors in using Taylor's hypothesis to transform measurements obtained in a temporal (or phase) frame onto a spatial one were evaluated. For the first time, phase-averaged ('real') spanwise and streamwise vorticity data measured on a three-dimensional grid were compared directly to those obtained using Taylor's hypothesis. The results show that even the qualitative features of the spanwise and streamwise vorticity distributions given by the two techniques can be very different. This is particularly true in the region of the spanwise roller pairing. The phase-averaged spanwise and streamwise peak vorticity levels given by Taylor's hypothesis are typically lower (by up to 40%) compared to the real measurements.

Shapes of an Air Taylor Bubble in Stagnant Liquids Influenced by Different Surface Tensions

Science.gov (United States)

Lertnuwat, B.

2018-02-01

The aim of this work is to propose an empirical model for predicting shapes of a Taylor bubble, which is a part of slug flows, under different values of the surface tension in stagnant liquids by employing numerical simulations. The k - Ɛ turbulence model was used in the framework of finite volume method for simulating flow fields in a unit of slug flow and also the pressure distribution on a Taylor bubble surface. Assuming that an air pressure distribution inside the Taylor bubble must be uniform, a grid search method was exploited to find an appropriate shape of a Taylor bubble for six values of surface tension. It was found that the shape of a Taylor bubble would be blunter if the surface tension was increased. This was because the surface tension affected the Froude number, controlling the flow around a Taylor bubble. The simulation results were also compared with the Taylor bubble shape, created by the Dumitrescu-and-Taylor model and former studies in order to ensure that they were consistent. Finally, the empirical model was presented from the simulation results.

Preliminary study of Rayleigh-Taylor instability in wire-array Z-pinch

International Nuclear Information System (INIS)

He Kaihui; Feng Kaiming; Li Qiang; Gao Chunming

2000-01-01

It is important to research into the MHD Rayleigh-Taylor instability developed in Z-pinch implosion. A snowplough model of the single wire Z-pinch is presented. The perturbation amplitude of Rayleigh-Taylor instability in the wire-array Z-pinch is analyzed quantitatively. Sheared axial flow is put forward to mitigate and reduce the Rayleigh-Taylor instability. And other approaches used to mitigate MHD instability in such a super-fast process are explored

Algumas considerações sobre a sociologia de Alfred Schutz

Directory of Open Access Journals (Sweden)

Márcio Nicory Costa Souza

2012-07-01

Full Text Available http://dx.doi.org/10.5007/1806-5023.2012v9n1p1 O presente artigo apresenta algumas considerações sobre a perspectiva sociológica de Alfred Schutz. Para tal, tecemos breves considerações sobre a fenomenologia, em especial a partir das contribuições de Husserl. Trata-se, portanto, de um esforço para o entendimento de sua importância para as Ciências Sociais. Primeiramente, apresentamos as influências constitutivas do pensamento de Schutz, bem como suas principais ferramentas analíticas. Em seguida, pensando no “fazer ciência”, procedemos para reflexões analíticas da proposta de uma Sociologia Interpretativa.

An algorithm for symplectic implicit Taylor-map tracking

International Nuclear Information System (INIS)

Yan, Y.; Channell, P.; Syphers, M.

1992-10-01

An algorithm has been developed for converting an ''order-by-order symplectic'' Taylor map that is truncated to an arbitrary order (thus not exactly symplectic) into a Courant-Snyder matrix and a symplectic implicit Taylor map for symplectic tracking. This algorithm is implemented using differential algebras, and it is numerically stable and fast. Thus, lifetime charged-particle tracking for large hadron colliders, such as the Superconducting Super Collider, is now made possible

78 FR 12307 - Taylor, G. Tom; Notice of Filing

Science.gov (United States)

2013-02-22

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ID-5705-001] Taylor, G. Tom; Notice of Filing Take notice that on February 14, 2013, G. Tom Taylor filed an application to hold interlocking positions pursuant to section 305(b) of the Federal Power Act, 16 U.S.C. 825d(b), Part 45 of the...

Taylor dispersion of nanoparticles

Science.gov (United States)

Balog, Sandor; Urban, Dominic A.; Milosevic, Ana M.; Crippa, Federica; Rothen-Rutishauser, Barbara; Petri-Fink, Alke

2017-08-01

The ability to detect and accurately characterize particles is required by many fields of nanotechnology, including materials science, nanotoxicology, and nanomedicine. Among the most relevant physicochemical properties of nanoparticles, size and the related surface-to-volume ratio are fundamental ones. Taylor dispersion combines three independent phenomena to determine particle size: optical extinction, translational diffusion, and sheer-enhanced dispersion of nanoparticles subjected to a steady laminar flow. The interplay of these defines the apparent size. Considering that particles in fact are never truly uniform nor monodisperse, we rigorously address particle polydispersity and calculate the apparent particle size measured by Taylor dispersion analysis. We conducted case studies addressing aqueous suspensions of model particles and large-scale-produced "industrial" particles of both academic and commercial interest of various core materials and sizes, ranging from 15 to 100 nm. A comparison with particle sizes determined by transmission electron microscopy confirms that our approach is model-independent, non-parametric, and of general validity that provides an accurate account of size polydispersity—independently on the shape of the size distribution and without any assumption required a priori.

Electrochemical Analysis of Taylor Vortices.

Czech Academy of Sciences Publication Activity Database

Wouahbi, F.; Allaf, K.; Sobolík, Václav

2007-01-01

Roč. 37, 1 (2007) , s. 57-62 ISSN 0021-891X Institutional research plan: CEZ:AV0Z40720504 Keywords : electrodiffusion method * taylor vortices * three-segment electrode Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.417, year: 2007

An endogenous Taylor condition in an endogenous growth monetary policy model

OpenAIRE

Le, Mai Vo; Gillman, Max; Minford, Patrick

2007-01-01

The paper derives a Taylor condition as part of the agent's equilibrium behavior in an endogenous growth monetary economy. It shows the assumptions necessary to make it almost identical to the original Taylor rule, and that it can interchangably take a money supply growth rate form. From the money supply form, simple policy experiments are conducted. A full central bank policy model is derived that includes the Taylor condition along with equations comparable to the standard aggregate-demand/...

New phenomena in variable-density Rayleigh-Taylor turbulence

Energy Technology Data Exchange (ETDEWEB)

Livescu, D; Ristorcelli, J R; Petersen, M R; Gore, R A, E-mail: livescu@lanl.gov [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

2010-12-15

This paper presents several issues related to mixing and turbulence structure in buoyancy-driven turbulence at low to moderate Atwood numbers, A, found from direct numerical simulations in two configurations: classical Rayleigh-Taylor instability and an idealized triply periodic Rayleigh-Taylor flow. Simulations at A up to 0.5 are used to examine the turbulence characteristics and contrast them with those obtained close to the Boussinesq approximation. The data sets used represent the largest simulations to date in each configuration. One of the more remarkable issues explored, first reported in (Livescu and Ristorcelli 2008 J. Fluid Mech. 605 145-80), is the marked difference in mixing between different density fluids as opposed to the mixing that occurs between fluids of commensurate densities, corresponding to the Boussinesq approximation. Thus, in the triply periodic configuration and the non-Boussinesq case, an initially symmetric density probability density function becomes skewed, showing that the mixing is asymmetric, with pure heavy fluid mixing more slowly than pure light fluid. A mechanism producing the mixing asymmetry is proposed and the consequences for the classical Rayleigh-Taylor configuration are discussed. In addition, it is shown that anomalous small-scale anisotropy found in the homogeneous configuration (Livescu and Ristorcelli 2008 J. Fluid Mech. 605 145-80) and Rayleigh-Taylor turbulence at A=0.5 (Livescu et al 2008 J. Turbul. 10 1-32) also occurs near the Boussinesq limit. Results pertaining to the moment closure modelling of Rayleigh-Taylor turbulence are also presented. Although the Rayleigh-Taylor mixing layer width reaches self-similar growth relatively fast, the lower-order terms in the self-similar expressions for turbulence moments have long-lasting effects and derived quantities, such as the turbulent Reynolds number, are slow to follow the self-similar predictions. Since eddy diffusivity in the popular gradient transport hypothesis

The Philosophical Genealogy of Taylor's Social Imaginaries: A Complex History of Ideas and Predecessors.

Science.gov (United States)

Vanheeswijck, Guido M

2017-01-01

The deepest sources of Charles Taylor's use of the concept "social imaginaries" are often related to political philosophy or social anthropology (Anderson, Castoriadis). The purpose of this article is to show that they also form part of Taylor's struggle to overcome the epistemological construal in modern philosophy and culture. Taylor locates the concept "social imaginaries" in the Kantian tradition, identifying their role to that of transcendental schemes. However, there remains a central difference between Kant's transcendental schemes and Taylor's social imaginaries. To elucidate that difference, this article will track the philosophical genealogy of Taylor's concept of "social imaginaries" in three steps.

A Paradoxical Partnership in Higher Education: The Alliance between Alfred C. Kinsey and Herman B Wells

Science.gov (United States)

Beineke, John A.

2015-01-01

Herman B Wells served as president of Indiana University from 1938 to 1962--from the days of the Great Depression into the turbulent 1960s. Alfred C. Kinsey was a professor, zoologist, and human sexuality researcher at Indiana University from 1920 until his death in 1956. A unique and paradoxical professional relationship existed between these two…

Alfred Walter Campbell's return to Australia.

Science.gov (United States)

Macmillan, Malcolm

2018-01-01

Alfred Walter Campbell (1868-1937) established the basic cytoarchitectonic structure of the human brain while he was working as a pathologist at the Rainhill Lunatic Asylum near Liverpool in the United Kingdom. He returned to Australia in 1905 and continued doing research while establishing a neurological practice. His research over the next 17 years focused on four topics: (a) localisation in the cerebellum, (b) the neuroses and psychoses in war, (c) localisation in the cerebral cortex of the gorilla, and (d) the causes and pathology of the mysterious Australian "X" Disease (later known as Murray Valley encephalitis). In this article, I elaborate on his research in these areas, which provided evidence (a) against Louis Bolk's thesis that variation in the size of the cerebellar cortex reflected variation in the amount of cortex controlling various groups of muscle, (b) against the view that the neuroses and psychoses in war were different from those in civilian life, (c) for a parcelation of the cortex of the gorilla brain that supported his earlier findings in the higher apes, and (d) on the cause and pathophysiology of Australian "X" disease. Much of this research was overlooked, but it remains of considerable value and historical significance.

The three faces of bounded reliability: Alfred Chandler and the micro-foundations of management theory

OpenAIRE

Kano, Liena; Verbeke, Alain

2015-01-01

Alfred Chandler, the celebrated business historian, provided detailed descriptions of the reasons for failed human commitments and the managerial tools needed to prevent/remediate such failings in the context of large business firms. Chandler's historical narrative identifies three distinct “faces” of bounded reliability—opportunism, benevolent preference reversal, and identity-based discordance—as the main drivers of commitment failure. Adopting bounded reliability (BRel) as a micro-foundati...

Neo-Taylorism in Educational Administration?

Science.gov (United States)

Gronn, Peter C.

1982-01-01

Reviews eight recent observational studies of school administrators and criticizes the studies' use of "time and motion" assumptions drawn from Frederick Winslow Taylor's ideas. Outlines an alternate approach based on "thick" description of administrators' work, including their talk, as exemplified in James Boswell's biography…

The Interpretation Of Metaphor Found In 20 Songs Of Taylor Swift

OpenAIRE

Desriani, Shella

2015-01-01

This paper entitled The interpretation of metaphor found in 20 of taylor swift. this paper discuss the types and meaning of metaphor in the lyrics of the song taylor swift. The purpose of this paper is to analyze types of metaphor in the form of simile, personification and hyperbole contained in the lyrics of the song taylor swift. In this paper the authors wrote the paper used the method of literature, collect some data from some books, and the internet. the lyric which contained metaphors i...

Rapid Calculation of Spacecraft Trajectories Using Efficient Taylor Series Integration

Science.gov (United States)

Scott, James R.; Martini, Michael C.

2011-01-01

A variable-order, variable-step Taylor series integration algorithm was implemented in NASA Glenn's SNAP (Spacecraft N-body Analysis Program) code. SNAP is a high-fidelity trajectory propagation program that can propagate the trajectory of a spacecraft about virtually any body in the solar system. The Taylor series algorithm's very high order accuracy and excellent stability properties lead to large reductions in computer time relative to the code's existing 8th order Runge-Kutta scheme. Head-to-head comparison on near-Earth, lunar, Mars, and Europa missions showed that Taylor series integration is 15.8 times faster than Runge- Kutta on average, and is more accurate. These speedups were obtained for calculations involving central body, other body, thrust, and drag forces. Similar speedups have been obtained for calculations that include J2 spherical harmonic for central body gravitation. The algorithm includes a step size selection method that directly calculates the step size and never requires a repeat step. High-order Taylor series integration algorithms have been shown to provide major reductions in computer time over conventional integration methods in numerous scientific applications. The objective here was to directly implement Taylor series integration in an existing trajectory analysis code and demonstrate that large reductions in computer time (order of magnitude) could be achieved while simultaneously maintaining high accuracy. This software greatly accelerates the calculation of spacecraft trajectories. At each time level, the spacecraft position, velocity, and mass are expanded in a high-order Taylor series whose coefficients are obtained through efficient differentiation arithmetic. This makes it possible to take very large time steps at minimal cost, resulting in large savings in computer time. The Taylor series algorithm is implemented primarily through three subroutines: (1) a driver routine that automatically introduces auxiliary variables and

Bubble behavior in a vertical Taylor-Couette flow

International Nuclear Information System (INIS)

Murai, Y; Oiwa, H; Takeda, Y

2005-01-01

Bubble distributions organized in a vertical Taylor-Couette flow are experimentally investigated. Modification of shear stress due to bubbles is measured with a torque sensor installed on the rotating inner cylinder. The wall shear stress decreases as bubbles are injected in all the tested range of Re from 600 to 4500. The drag reduction ratio per void fraction measured in the present experiment, which indicates net gain of the drag reduction, has been evaluated. The gain was more than unity for Re 4000. The maximum gain achieved was around 10 at Re = 600, at which point the bubbles dispersed widely on the inner cylinder surface and effectively restrict momentum exchange of fluid between the two walls. The expansion of Taylor vortices in the vertical direction by the presence of bubbles was confirmed by flow visualization including particle tracking velocimetry. Such bubble behaviours interacting with Taylor vortices are discussed in detail in this paper

Photonic arbitrary waveform generator based on Taylor synthesis method

DEFF Research Database (Denmark)

Liao, Shasha; Ding, Yunhong; Dong, Jianji

2016-01-01

Arbitrary waveform generation has been widely used in optical communication, radar system and many other applications. We propose and experimentally demonstrate a silicon-on-insulator (SOI) on chip optical arbitrary waveform generator, which is based on Taylor synthesis method. In our scheme......, a Gaussian pulse is launched to some cascaded microrings to obtain first-, second- and third-order differentiations. By controlling amplitude and phase of the initial pulse and successive differentiations, we can realize an arbitrary waveform generator according to Taylor expansion. We obtain several typical...... waveforms such as square waveform, triangular waveform, flat-top waveform, sawtooth waveform, Gaussian waveform and so on. Unlike other schemes based on Fourier synthesis or frequency-to-time mapping, our scheme is based on Taylor synthesis method. Our scheme does not require any spectral disperser or large...

Taylor Hydro plant goes live

International Nuclear Information System (INIS)

Anon.

2000-01-01

The 12.75 MW Taylor Hydroelectric Plant in Magrath, Alberta, synchronized its generator with the Alberta Power Grid and began production in April 2000. The plant is located on Government of Alberta irrigation works and is owned by Canadian Hydro Developers. During the irrigation season the plant will generate approximately 40 million kilowatt hours of zero-emission 'green' power for consumption, enough to power 5,000 homes for a year. The Taylor plant is a joint venture with EPCOR Power Development Corporation, a wholly-owned subsidiary of EPCOR Inc., the City of Edmonton utility. Canadian Hydro Developers also owns a 19 MW wind plant and a 6 MW gas plant in Alberta and five other 'run of river' hydro plants in Ontario and British Columbia. The company is committed to the concept of low-impact power generation; its ownership of wind run-of-river hydro and gas-fired facilities is proof of that commitment

Micromixer based on Taylor dispersion

International Nuclear Information System (INIS)

Yang, H; Nguyen, N-T; Huang, X

2006-01-01

This paper reports an analytical model, the fabrication and the characterization of a polymeric micromixer based on Taylor dispersion. Due to the distributed velocity field over the channel cross section, the effective dispersion in axial direction in a microchannel is much stronger than the pure molecular diffusion. In our work, squential segmentation was used in the micromixer for improving mixing in a microchannel. The micromixer was designed and fabricated based on lamination of five 100-μm-thick polymer sheets. Rubber valve seats were embedded between the forth and the fifth layers. The polymer layers were machined using a CO 2 laser. The lamination of the five layers was carried out by a commercial hot laminator (Aurora LM-450HC). External solenoid actuators are used for closing the valves at the mixer inlets. The experimental results confirm the effect of Taylor dispersion. Mixing ratio can be adjusted by pulse width modulation of the control signal of the solenoids

Numerical simulation of Rayleigh-Taylor turbulent mixing layers

International Nuclear Information System (INIS)

Poujade, O.; Lardjane, N.; Peybernes, M.; Boulet, M.

2009-01-01

Accelerations in actual Rayleigh-Taylor instabilities are often variable. This article focuses on a particular class of variable accelerations where g(t) ∝ t n . A reference database is built from high resolution hydrodynamic numerical simulations. The successful comparison with a simple OD analytical model and the statistical 2SFK (2-Structure, 2-Fluid, 2-Turbulence) turbulence model is provided. Moreover, we show the difference between the mechanism at play in the Rayleigh-Taylor turbulent mixing zone and Kolmogorov's in the self similar developed turbulent regime. (authors)

Towards finite density QCD with Taylor expansions

International Nuclear Information System (INIS)

Karsch, F.; Schaefer, B.-J.; Wagner, M.; Wambach, J.

2011-01-01

Convergence properties of Taylor expansions of observables, which are also used in lattice QCD calculations at non-zero chemical potential, are analyzed in an effective N f =2+1 flavor Polyakov quark-meson model. A recently developed algorithmic technique allows the calculation of higher-order Taylor expansion coefficients in functional approaches. This novel technique is for the first time applied to an effective N f =2+1 flavor Polyakov quark-meson model and the findings are compared with the full model solution at finite densities. The results are used to discuss prospects for locating the QCD phase boundary and a possible critical endpoint in the phase diagram.

Stability of an expanding cylindrical plasma envelope: Rayleigh--Taylor instability

International Nuclear Information System (INIS)

Han, S.J.

1982-01-01

The stability of a cylindrically symmetric plasma envelope driven outward by blast waves is considered. The plasma fluid is assumed to be a compressible, isentropic gas describable as an ideal gas ( p = arho/sup γ/, γ>1). The stability problem of such an envelope undergoing self-similar motion is solved by considering the initial-value problem. It is shown that in the early phase of an expansion, the envelope is unstable to Rayleigh--Taylor modes which develop at the inner surface. In the later phase of the expansion, the Rayleigh--Taylor modes are weakened due to the geometrical divergence effect. The implications of the time-dependent behavior of the Rayleigh--Taylor instability for plasma switches are discussed

Qualitative Research in Organizational Studies: Phenomenological Contributions of Alfred Schütz Pesquisa Qualitativa nos Estudos Organizacionais: Contribuições Fenomenológicas de Alfred Schütz

Directory of Open Access Journals (Sweden)

Fernando Gomes de Paiva Júnior

2009-03-01

Full Text Available Modern science is in crisis. Today, we live in a scientific paradigm transition motivated by differences and complexities. In the organizational field, qualitative research emerges as a methodological alternative to the researcher. It aids the contemporary understanding of the actor involved with the management phenomenon, as it reveals his/her impressions and feelings related to personal and professional lived experiences. The interpretative approach of Alfred Schütz's social phenomenology constitutes one of the variants of the phenomenological movement that makes knowledge of essences possible, and constitutes a type of "intelligible armor" of the organizational being's understanding, which has its structure and specific laws.

Fluctuation scaling, Taylor's law, and crime.

Directory of Open Access Journals (Sweden)

Quentin S Hanley

Full Text Available Fluctuation scaling relationships have been observed in a wide range of processes ranging from internet router traffic to measles cases. Taylor's law is one such scaling relationship and has been widely applied in ecology to understand communities including trees, birds, human populations, and insects. We show that monthly crime reports in the UK show complex fluctuation scaling which can be approximated by Taylor's law relationships corresponding to local policing neighborhoods and larger regional and countrywide scales. Regression models applied to local scale data from Derbyshire and Nottinghamshire found that different categories of crime exhibited different scaling exponents with no significant difference between the two regions. On this scale, violence reports were close to a Poisson distribution (α = 1.057 ± 0.026 while burglary exhibited a greater exponent (α = 1.292 ± 0.029 indicative of temporal clustering. These two regions exhibited significantly different pre-exponential factors for the categories of anti-social behavior and burglary indicating that local variations in crime reports can be assessed using fluctuation scaling methods. At regional and countrywide scales, all categories exhibited scaling behavior indicative of temporal clustering evidenced by Taylor's law exponents from 1.43 ± 0.12 (Drugs to 2.094 ± 0081 (Other Crimes. Investigating crime behavior via fluctuation scaling gives insight beyond that of raw numbers and is unique in reporting on all processes contributing to the observed variance and is either robust to or exhibits signs of many types of data manipulation.

Fluctuation scaling, Taylor's law, and crime.

Science.gov (United States)

Hanley, Quentin S; Khatun, Suniya; Yosef, Amal; Dyer, Rachel-May

2014-01-01

Fluctuation scaling relationships have been observed in a wide range of processes ranging from internet router traffic to measles cases. Taylor's law is one such scaling relationship and has been widely applied in ecology to understand communities including trees, birds, human populations, and insects. We show that monthly crime reports in the UK show complex fluctuation scaling which can be approximated by Taylor's law relationships corresponding to local policing neighborhoods and larger regional and countrywide scales. Regression models applied to local scale data from Derbyshire and Nottinghamshire found that different categories of crime exhibited different scaling exponents with no significant difference between the two regions. On this scale, violence reports were close to a Poisson distribution (α = 1.057 ± 0.026) while burglary exhibited a greater exponent (α = 1.292 ± 0.029) indicative of temporal clustering. These two regions exhibited significantly different pre-exponential factors for the categories of anti-social behavior and burglary indicating that local variations in crime reports can be assessed using fluctuation scaling methods. At regional and countrywide scales, all categories exhibited scaling behavior indicative of temporal clustering evidenced by Taylor's law exponents from 1.43 ± 0.12 (Drugs) to 2.094 ± 0081 (Other Crimes). Investigating crime behavior via fluctuation scaling gives insight beyond that of raw numbers and is unique in reporting on all processes contributing to the observed variance and is either robust to or exhibits signs of many types of data manipulation.

Stroke, music, and creative output: Alfred Schnittke and other composers.

Science.gov (United States)

Zagvazdin, Yuri

2015-01-01

Alfred Schnittke (1934-1998), a celebrated Russian composer of the twentieth century, suffered from several strokes which affected his left cerebral hemisphere. The disease, however, did not diminish his musical talent. Moreover, he stated that his illness in a way facilitated his work. The composer showed amazingly high productivity after his first and second injuries of the central nervous system. The main topic of this chapter is the effect of strokes on Schnittke's output, creativity, and style of music. A brief biography of the composer with the chronology of his brain hemorrhages is included. In addition, the influence of cerebrovascular lesions on creative potential of other prominent composers such as Benjamin Britten, Jean Langlais, Vissarion Shebalin, Igor Stravinsky, and Ira Randall Thompson is discussed. © 2015 Elsevier B.V. All rights reserved.

Charles Robert Darwin and Alfred Russel Wallace: their dispute over the units of selection.

Science.gov (United States)

Ruse, Michael

2013-12-01

Charles Darwin and Alfred Russel Wallace independently discovered the mechanism of natural selection for evolutionary change. However, they viewed the working of selection differently. For Darwin, selection was always focused on the benefit for the individual. For Wallace, selection was as much something of benefit for the group as for the individual. This difference is traced to their different background political-economic views, with Darwin in favor of Adam Smith's view of society and Wallace following Robert Owen in being a socialist.

Atomic Power | Taylor | Zede Journal

African Journals Online (AJOL)

Zede Journal. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 3 (1968) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register. Atomic Power. D Taylor. Abstract. No Abstract. Full Text: EMAIL FREE FULL TEXT ...

Rayleigh-Taylor instability of cylindrical jets with radial motion

Energy Technology Data Exchange (ETDEWEB)

Chen, Xiang M. [GE Nuclear, Wilmington, NC (United States); Schrock, V.E.; Peterson, P.F. [Univ. of California, Berkeley, CA (United States)

1995-09-01

Rayleigh-Taylor instability of an interface between fluids with different densities subjected to accelleration normal to itself has interested researchers for almost a century. The classic analyses of a flat interface by Rayleigh and Taylor have shown that this type of instability depends on the direction of acceleration and the density differences of the two fluids. Plesset later analyzed the stability of a spherically symmetric flows (and a spherical interface) and concluded that the instability also depends on the velocity of the interface as well as the direction and magnitude of radial acceleration. The instability induced by radial motion in cylindrical systems seems to have been neglected by previous researchers. This paper analyzes the Rayleigh-Taylor type of the spherical case, the radial velocity also plays an important role. As an application, the example of a liquid jet surface in an Inertial Confinement Fusion (ICF) reactor design is analyzed.

Repainting, modifying, smashing Taylorism

OpenAIRE

Pruijt, Hans

2000-01-01

textabstractAbstract Survey data show that post-Tayloristic production concepts are not developing to the extent that many researchers had originally expected. It also is inadequate to portray post-Taylorism as a development that is happening, but just slower than expected. This is inadequate because there are counter-tendencies: the resurgence of the assembly line in the highly paradigmatic automobile assembly; the rise of the McDonalds-type organization; and continuing skills-replacing auto...

Rayleigh-Taylor instability of cylindrical jets with radial motion

International Nuclear Information System (INIS)

Chen, X.M.; Schrock, V.E.; Peterson, P.F.

1997-01-01

Rayleigh-Taylor instability of an interface between fluids with different densities subjected to acceleration normal to itself has interested researchers for almost a century. The classic analyses of a flat interface by Rayleigh and Taylor have shown that this type of instability depends on the direction of acceleration and the density differences of the two fluids. Plesset later analyzed the stability of a spherically symmetric flows (and a spherical interface) and concluded that the instability also depends on the velocity of the interface as well as the direction and magnitude of radial acceleration. The instability induced by radial motion in cylindrical systems seems to have been neglected by previous researchers. This paper analyzes the Rayleigh-Taylor type of instability for a cylindrical surface with radial motions. The results of the analysis show that, like the spherical case, the radial velocity also plays an important role. As an application, the example of a liquid jet surface in an Inertial Confinement Fusion (ICF) reactor design is analyzed. (orig.)

Dynamic stabilization of the imploding-shell Rayleigh-Taylor instability

International Nuclear Information System (INIS)

Boris, J.P.

1977-01-01

A method for dynamic stabilization of the Rayleigh-Taylor (R-T) instability on the surface of an imploding fusion pellet is discussed. The driving laser beams are modulated in intensity so the ablation layer is subject to a rapidly and strongly oscillating acceleration. A substantial band of the Rayleigh-Taylor instability spectrum can be stabilized by this oscillation even though the time average acceleration vector lies in the destabilizing direction. By adjusting the frequency, structure, and amplitude of the modulation, the band of dynamically stabilized modes can be made to include the most unstable and dangerous modes. Thus considerably higher aspect ratio shells (i.e., thinner shells) could implode successfully than had been previously considered stable enough. Both theory and numerical simulations support this conclusion for the case of laser-driven pellet implosions. Similar modulation via transverse beam oscillations or parallel bunching should also work to stabilize the most dangerous surface Rayleigh-Taylor modes in relativistic electron-, ion- and heavy ion-pellet fusion schemes. (U.K.)

The right versus the good? On the right in the Philosophy of Charles Taylor

Directory of Open Access Journals (Sweden)

Javier García Caladín

2013-05-01

Full Text Available The aim of this article is to analyze the famous confrontation between the right and the good. We start with the analysis of Charles Taylor about the different significances of the good and his criticism to a procedural and restrictive approach of the moral (such as Habermas and Kymlicka. Secondly, we review in depth the ethics of Taylor and we stress the vague remark of «the just» in the use of Taylor. Finally, we evaluate the deontological deficiencies of the ethics of Taylor and try to find other ways to complement it.

An Application of Taylor Models to the Nakao Method on ODEs

OpenAIRE

Yamamoto, Nobito; Komori, Takashi

2009-01-01

The authors give short survey on validated computaion of initial value problems for ODEs especially Taylor model methods. Then they propose an application of Taylor models to the Nakao method which has been developed for numerical verification methods on PDEs and apply it to initial value problems for ODEs with some numerical experiments.

Expressing the remainder of the Taylor polynomial when the function lacks smoothness

Czech Academy of Sciences Publication Activity Database

Hošek, Radim

2017-01-01

Roč. 72, č. 3 (2017), s. 126-130 ISSN 0013-6018 Institutional support: RVO:67985840 Keywords : Taylor polynomial * Taylor theorem Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics http://www.ems-ph.org/doi/10.4171/EM/335

Alfred Tarski early work in Poland—geometry and teaching

CERN Document Server

McFarland, Joanna; Smith, James

2014-01-01

Alfred Tarski (1901–1983) was a renowned Polish/American mathematician, a giant of the twentieth century, who helped establish the foundations of geometry, set theory, model theory, algebraic logic, and universal algebra. Throughout his career, he taught mathematics and logic at universities and sometimes in secondary schools. Many of his writings before 1939 were in Polish and remained inaccessible to most mathematicians and historians until now. This self-contained book focuses on Tarski’s early contributions to geometry and mathematics education, including the famous Banach–Tarski paradoxical decomposition of a sphere as well as high-school mathematical topics and pedagogy. These themes are significant since Tarski’s later research on geometry and its foundations stemmed in part from his early employment as a high-school mathematics teacher and teacher-trainer. The book contains careful translations and much newly uncovered social background of these works written during Tarski’s years in Poland....

Discussion of Alfred Alder's preface to The Diary of Vaslav Nijinsky.

Science.gov (United States)

Ansbacher, H L

1981-07-01

In his preface to The Diary of Vaslav Nijinsky, Alfred Adler (1) found his theory of the dynamics of schizophrenia supported in the Diary, (2) alluded to Nijinsky's prepsychotic personality, and (3) briefly touched on the possibility and conditions of recovery. To add to the understanding of Adler's "Preface," this discussion (1) expands his theory of schizophrenia, (2) gives some concrete data of Nijinsky's prepsychotic personality, (3) describes two episodes of recovery subsequent to the "Preface," and (4) introduces an important aspect of Adler's theory, which he had to omit out of consideration for Nijinsky's wife, Romola-namely, her role in her husband's disorder. With the larger theoretical and historical context established. Adler's "Preface" can be appreciated for its predictive validity.

Korsakoff's Syndrome and Modern German Literature: Alfred Döblin's Medical Dissertation

Directory of Open Access Journals (Sweden)

Roland Dollinger

1998-01-01

Full Text Available This essay deals with the historical and cultural interrelationships between the medical and psychiatric discourses on memory and memory disorders at the end of the nineteenth century and the invention of an abstract and highly dissociated literary style in modern German literature. An historical reading of Alfred Döblin's medical dissertation (1905 on Korsakoff's syndrome, an amnestic disorder, shows the confluence of both his psychiatric and aesthetic interests in human memory and its failures. The essay analyzes Döblin's medical dissertation less as the contribution of a young psychiatrist to his discipline but rather as an historical text that challenges us to see where some of the medical and aesthetic concerns of early twentieth-century German culture meet.

Direct numerical simulation of the Rayleigh-Taylor instability with the spectral element method

International Nuclear Information System (INIS)

Zhang Xu; Tan Duowang

2009-01-01

A novel method is proposed to simulate Rayleigh-Taylor instabilities using a specially-developed unsteady three-dimensional high-order spectral element method code. The numerical model used consists of Navier-Stokes equations and a transport-diffusive equation. The code is first validated with the results of linear stability perturbation theory. Then several characteristics of the Rayleigh-Taylor instabilities are studied using this three-dimensional unsteady code, including instantaneous turbulent structures and statistical turbulent mixing heights under different initial wave numbers. These results indicate that turbulent structures of Rayleigh-Taylor instabilities are strongly dependent on the initial conditions. The results also suggest that a high-order numerical method should provide the capability of simulating small scale fluctuations of Rayleigh-Taylor instabilities of turbulent flows. (authors)

Rayleigh Taylor instability of two superposed compressible fluids in un-magnetized plasma

International Nuclear Information System (INIS)

Sharma, P K; Tiwari, A; Argal, S; Chhajlani, R K

2014-01-01

The linear Rayleigh Taylor instability of two superposed compressible Newtonian fluids is discussed with the effect of surface tension which can play important roles in space plasma. As in both the superposed Newtonian fluids, the system is stable for potentially stable case and unstable for potentially unstable case in the present problem also. The equations of the problem are solved by normal mode method and a dispersion relation is obtained for such a system. The behaviour of growth rate is examined in the presence of surface tension and it is found that the surface tension has stabilizing influence on the Rayleigh Taylor instability of two superposed compressible fluids. Numerical analysis is performed to show the effect of sound velocity and surface tension on the growth rate of Rayleigh Taylor instability. It is found that both parameters have stabilizing influence on the growth rate of Rayleigh Taylor instability.

Rayleigh-Taylor instability and mushroom-pattern formation in a two-component Bose-Einstein condensate

International Nuclear Information System (INIS)

Sasaki, Kazuki; Suzuki, Naoya; Saito, Hiroki; Akamatsu, Daisuke

2009-01-01

The Rayleigh-Taylor instability at the interface in an immiscible two-component Bose-Einstein condensate is investigated using the mean field and Bogoliubov theories. Rayleigh-Taylor fingers are found to grow from the interface and mushroom patterns are formed. Quantized vortex rings and vortex lines are then generated around the mushrooms. The Rayleigh-Taylor instability and mushroom-pattern formation can be observed in a trapped system.

Slavnov-Taylor constraints for nontrivial backgrounds

International Nuclear Information System (INIS)

Binosi, D.; Quadri, A.

2011-01-01

We devise an algebraic procedure for the evaluation of Green's functions in SU(N) Yang-Mills theory in the presence of a nontrivial background field. In the ghost-free sector the dependence of the vertex functional on the background is shown to be uniquely determined by the Slavnov-Taylor identities in terms of a certain 1-PI correlator of the covariant derivatives of the ghost and the antighost fields. At nonvanishing background this amplitude is shown to encode the quantum deformations to the tree-level background-quantum splitting. The approach only relies on the functional identities of the model (Slavnov-Taylor identities, b-equation, antighost equation) and thus it is valid beyond perturbation theory, and, in particular, in a lattice implementation of the background field method. As an example of the formalism we analyze the ghost two-point function and the Kugo-Ojima function in an instanton background in SU(2) Yang-Mills theory, quantized in the background Landau gauge.

Contexto y pensamiento de Charles Taylor sobre el consenso

Directory of Open Access Journals (Sweden)

Doris Elena Ospina Muñoz

2017-01-01

Full Text Available El artículo sostiene que el consenso no es un tema de primer orden en la filosofía política de Charles Taylor, pero una lectura orientada al problema puede ofrecer los elementos para establecer una teoría sobre dicha noción e identificar los argumentos para su justificación. Además, se enfatiza en el contexto de discusión que permite introducir la filosofía de Taylor como un modo de pensar sobre el consenso, alternativo al constructivismo.

Rayleigh-Taylor/gravitational instability in dense magnetoplasmas

Energy Technology Data Exchange (ETDEWEB)

Ali, S., E-mail: shahid.ali@ncp.edu.p [National Centre for Physics, Quaid-i-Azam University Campus, Islamabad (Pakistan); IPFN, Instituto Superior Tecnico, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Ahmed, Z. [COMSATS Institute of Information Technology, Department of Physics, Wah Campus (Pakistan); Mirza, Arshad M. [Theoretical Plasma Physics Group, Physics Department, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Ahmad, I. [COMSATS Institute of Information Technology, Department of Physics, Islamabad Campus (Pakistan)

2009-08-10

The Rayleigh-Taylor instability is investigated in a nonuniform dense quantum magnetoplasma. For this purpose, a quantum hydrodynamical model is used for the electrons whereas the ions are assumed to be cold and classical. The dispersion relation for the Rayleigh-Taylor instability becomes modified with the quantum corrections associated with the Fermi pressure law and the quantum Bohm potential force. Numerically, it is found that the quantum speed and density gradient significantly modify the growth rate of RT instability. In a dense quantum magnetoplasma case, the linear growth rate of RT instability becomes significantly higher than its classical value and the modes are found to be highly localized. The present investigation should be useful in the studies of dense astrophysical magnetoplasmas as well as in laser-produced plasmas.

Rayleigh-Taylor/gravitational instability in dense magnetoplasmas

International Nuclear Information System (INIS)

Ali, S.; Ahmed, Z.; Mirza, Arshad M.; Ahmad, I.

2009-01-01

The Rayleigh-Taylor instability is investigated in a nonuniform dense quantum magnetoplasma. For this purpose, a quantum hydrodynamical model is used for the electrons whereas the ions are assumed to be cold and classical. The dispersion relation for the Rayleigh-Taylor instability becomes modified with the quantum corrections associated with the Fermi pressure law and the quantum Bohm potential force. Numerically, it is found that the quantum speed and density gradient significantly modify the growth rate of RT instability. In a dense quantum magnetoplasma case, the linear growth rate of RT instability becomes significantly higher than its classical value and the modes are found to be highly localized. The present investigation should be useful in the studies of dense astrophysical magnetoplasmas as well as in laser-produced plasmas.

Direct Numerical Simulation of the Rayleigh−Taylor Instability with the Spectral Element Method

International Nuclear Information System (INIS)

Xu, Zhang; Duo-Wang, Tan

2009-01-01

A novel method is proposed to simulate Rayleigh−Taylor instabilities using a specially-developed unsteady three-dimensional high-order spectral element method code. The numerical model used consists of Navier–Stokes equations and a transport-diffusive equation. The code is first validated with the results of linear stability perturbation theory. Then several characteristics of the Rayleigh−Taylor instabilities are studied using this three-dimensional unsteady code, including instantaneous turbulent structures and statistical turbulent mixing heights under different initial wave numbers. These results indicate that turbulent structures of Rayleigh–Taylor instabilities are strongly dependent on the initial conditions. The results also suggest that a high-order numerical method should provide the capability of simulating small scale fluctuations of Rayleigh−Taylor instabilities of turbulent flows. (fundamental areas of phenomenology (including applications))

An Attempt to Extend Taylor-Spence Drive Theory to Vocational Choice Behavior

Science.gov (United States)

Sharf, Richard S.

1972-01-01

Predictions were made from Taylor-Spence drive theory about vocational choice behavior. Although the results did not specifically support the predictions made from Taylor-Spence theory, they indicated the potential usefulness of certain concepts in this theory and suggested several lines of inquiry for further research. (Author)

Reconnaissance study of the Taylor Mountains pluton, southwestern Alaska

Science.gov (United States)

Hudson, Travis L.; Miller, Marti L.; Klimasauskas, Edward P.; Layer, Paul W.

2010-01-01

The Taylor Mountains pluton is a Late Cretaceous to early Tertiary (median age 65 + or ? 2 Ma) epizonal, composite biotite granite stock located about 235 km (145 mi) northeast of Dillingham in southwestern Alaska. This 30 km2 (12 mi2) pluton has sharp and discordant contacts with hornfels that developed in Upper Cretaceous clastic sedimentary rocks of the Kuskokwim Group. The three intrusive phases in the Taylor Mountains pluton, in order of emplacement, are (1) porphyritic granite containing large K-feldspar phenocrysts in a coarse-grained groundmass, (2) porphyritic granite containing large K-feldspar and smaller, but still coarse, plagioclase, quartz, and biotite phenocrysts in a fine-grained groundmass, and (3) fine-grained, leucocratic, equigranular granite. The porphyritic granites have different emplacement histories, but similar compositions; averages are 69.43 percent SiO2, 1.62 percent CaO, 5.23 percent FeO+MgO, 3.11 percent Na2O, and 4.50 percent K2O. The fine-grained, equigranular granite is distinctly felsic compared to porphyritic granite; it averages 75.3 percent SiO2, 0.49 percent CaO, 1.52 percent FeO+MgO, 3.31 percent Na2O, and 4.87 percent K2O. Many trace elements including Ni, Cr, Sc, V, Ba, Sr, Zr, Y, Nb, La, Ce, Th, and Nd are strongly depleted in fine-grained equigranular granite. Trace elements are not highly enriched in any of the granites. Known hydrothermal alteration is limited to one tourmaline-quartz replacement zone in porphyritic granite. Mineral deposits in the Taylor Mountains area are primarily placer gold (plus wolframite, cassiterite, and cinnabar); sources for these likely include scattered veins in hornfels peripheral to the Taylor Mountain pluton. The granite magmas that formed the Taylor Mountains pluton are thought to represent melted continental crust that possibly formed in response to high heat flow in the waning stage of Late Cretaceous subduction beneath interior Alaska.

A cosmological Slavnov-Taylor identity

Science.gov (United States)

Collins, Hael; Holman, R.; Vardanyan, Tereza

2014-12-01

We develop a method for treating the consistency relations of inflation that includes the full time-evolution of the state. This approach relies only on the symmetries of the inflationary setting, in particular a residual conformal symmetry in the spatial part of the metric, along with general properties which hold for any quantum field theory. As a result, the consistency relations that emerge, which are essentially the Slavnov-Taylor identities associated with this residual conformal symmetry, apply very generally: they are true of the full Green's functions, hold largely independently of the particular inflationary model, and can be used for arbitrary states. We illustrate these techniques by showing the form assumed by the standard consistency relation between the two and three-point functions for the primordial scalar fluctuations when they are in a Bunch-Davies state. But because we have included the full evolution of the state, this approach works for a general initial state as well and does not need to have assumed that inflation began in the Bunch-Davies state. We explain how the Slavnov-Taylor identity is modified for these more general states.

Quantum effects on the Rayleigh-Taylor instability in a horizontal inhomogeneous rotating plasma

International Nuclear Information System (INIS)

Hoshoudy, G. A.

2009-01-01

The Rayleigh-Taylor instability is studied analytically in inhomogeneous plasma rotating uniformly in an external transverse magnetic field. The influence of the quantum mechanism is considered. For a stratified layer the linear growth rate is obtained. Some special cases that isolate the effect of various parameters on the growth rate of the Rayleigh-Taylor instability are discussed. It is shown that for some cases, the presence of the external transverse magnetic field beside the quantum effect will bring about more stability on the Rayleigh-Taylor instability.

Book Review: McCoy, Alfred, Policing America’s Empire: The United States, the Philippines, and the Rise of the Surveillance State

Directory of Open Access Journals (Sweden)

Salvador Santino F. Regilme, Jr

2010-01-01

Full Text Available Book Review of the Monograph: McCoy, Alfred (2009, Policing America’s Empire: The United States, the Philippines, and the Rise of the Surveillance State, Madison, Wisconsin: The University of Wisconsin Press ISBN 978-0-299-23414-0, 659 pages

Effects of thermal conduction and compressibility on Rayleigh-Taylor instability

International Nuclear Information System (INIS)

Takabe, Hideaki; Mima, Kunioki.

1980-01-01

In order to study the stability of the ablation front in laser driven implosion, the thermal conduction and compressibility effects on the Rayleigh-Taylor instability are considered. It is found that the thermal conduction effect cannot stabilize the Rayleigh-Taylor mode, but reduce the growth rate in the short wavelength case. But, the growth rate is found not to differ from the classical value √gk in the long wavelength limit, where the compressibility is essential. (author)

Taylor Dispersion Analysis as a promising tool for assessment of peptide-peptide interactions.

Science.gov (United States)

Høgstedt, Ulrich B; Schwach, Grégoire; van de Weert, Marco; Østergaard, Jesper

2016-10-10

Protein-protein and peptide-peptide (self-)interactions are of key importance in understanding the physiochemical behavior of proteins and peptides in solution. However, due to the small size of peptide molecules, characterization of these interactions is more challenging than for proteins. In this work, we show that protein-protein and peptide-peptide interactions can advantageously be investigated by measurement of the diffusion coefficient using Taylor Dispersion Analysis. Through comparison to Dynamic Light Scattering it was shown that Taylor Dispersion Analysis is well suited for the characterization of protein-protein interactions of solutions of α-lactalbumin and human serum albumin. The peptide-peptide interactions of three selected peptides were then investigated in a concentration range spanning from 0.5mg/ml up to 80mg/ml using Taylor Dispersion Analysis. The peptide-peptide interactions determination indicated that multibody interactions significantly affect the PPIs at concentration levels above 25mg/ml for the two charged peptides. Relative viscosity measurements, performed using the capillary based setup applied for Taylor Dispersion Analysis, showed that the viscosity of the peptide solutions increased with concentration. Our results indicate that a viscosity difference between run buffer and sample in Taylor Dispersion Analysis may result in overestimation of the measured diffusion coefficient. Thus, Taylor Dispersion Analysis provides a practical, but as yet primarily qualitative, approach to assessment of the colloidal stability of both peptide and protein formulations. Copyright © 2016 Elsevier B.V. All rights reserved.

On generalizations of the series of Taylor, Lagrange, Laurent and Teixeira

Directory of Open Access Journals (Sweden)

L. M. B. C. Campos

1990-01-01

Full Text Available The classical theorems of Taylor, Lagrange, Laurent and Teixeira, are extended from the representation of a complex function F(z, to its derivative F(ν(z of complex order ν, understood as either a ‘Liouville’ (1832 or a ‘Rieman (1847’ differintegration (Campos 1984, 1985; these results are distinct from, and alternative to, other extensions of Taylor's series using differintegrations (Osler 1972, Lavoie & Osler & Tremblay 1976. We consider a complex function F(z, which is analytic (has an isolated singularity at ζ, and expand its derivative of complex order F(ν(z, in an ascending (ascending-descending series of powers of an auxiliary function f(z, yielding the generalized Teixeira (Lagrange series, which includes, for f(z=z−ζ, the generalized Taylor (Laurent series. The generalized series involve non-integral powers and/or coefficients evaluated by fractional derivatives or integrals, except in the case ν=0, when the classical theorems of Taylor (1715, Lagrange (1770, Laurent (1843 and Teixeira (1900 are regained. As an application, these generalized series can be used to generate special functions with complex parameters (Campos 1986, e.g., the Hermite and Bessel types.

Alfred Adler, pioneer in prevention of mental disorders.

Science.gov (United States)

Ansbacher, H L

1990-09-01

Alfred Adler (1870-1937) one of the four original members of what was to become the Vienna Psychoanalytic Society, was the first to accept a humanistic-educational model of man in contrast to Freud's medical model of man. This was in line with his deep involvement with prevention; in fact his original interest was in medical prevention. The present paper describes how his work touched on all the points of the contemporary field of psychological prevention. He developed a personality theory most suitable for application in prevention, education and brief psychotherapy. He identified various categories of children at risk. He advocated the right to abortion partly to prevent the birth of a child severely at risk by being unwanted. He considered the then existing dominance of the male sex to be damaging to both sexes. He engaged in practical prevention work by addressing general audiences and especially teachers and by the establishment of and participation in Educational Counseling Centers. He felt that the honest psychologist for reasons of prevention is bound to social advocacy, and that a true psychology of mental health merges into a corresponding world philosophy. These points are fully documented with quotations and references.

Dominant Taylor Spectrum and Invariant Subspaces

Czech Academy of Sciences Publication Activity Database

Ambrozie, Calin-Grigore; Müller, Vladimír

2009-01-01

Roč. 61, č. 1 (2009), s. 101-111 ISSN 0379-4024 R&D Projects: GA ČR(CZ) GA201/06/0128 Institutional research plan: CEZ:AV0Z10190503 Keywords : Taylor spectrum * Scott-Brown technique * dominant spectrum Subject RIV: BA - General Mathematics Impact factor: 0.580, year: 2009

Salud mental y ética: el concepto de sentimiento de comunidad en la psicología de Alfred Adler

OpenAIRE

Oberst, Úrsula E.

1997-01-01

L'objectiu d'aquest article és presentar la figura del fundador de la psicologia individual, Alfred Adler (1870-1937). L'article se centra fonamentalment en el seu pensament de tipus filosòfic i psicològic i estudia el concepte de sentiment de comunitat (Gemeinschaftsgefühl), que és determinant en l'obra d'aquest autor.

A portrait of prefrontal lobotomy performed at the Royal Prince Alfred Hospital in Sydney by Dr Rex Money.

Science.gov (United States)

White, Richard T; McGee-Collett, Martin

2016-10-01

The objective of this article is to provide a portrait of prefrontal lobotomy performed at the Royal Prince Alfred Hospital, Sydney by the Head of Neurosurgery Dr Rex Money and to describe Dr Money's role in the promotion of psychosurgery in Sydney. We draw attention to an oral presentation by Dr Rex Money in 1951, a journal article written by Money, archival information held at the Royal Prince Alfred Hospital, including Dr Money's accounts of his travels and his reports regarding neurosurgery - both internationally and in Australia. Dr Rex Money performed a series of 13 prefrontal lobotomies between 1945 and 1951, and presented the theoretical basis for his series, his operative procedures and the outcomes at the annual meeting of its medical officers' association. Notwithstanding various deficiencies in his clinical research, Money's descriptions give a relatively comprehensive account of one of the first series of prefrontal lobotomies performed in Australia. The current article also describes Dr Money's contributions to the promotion of psychosurgery in Sydney, and illustrates the participation of a senior neurosurgeon and of a major Sydney teaching hospital during the psychosurgery saga. © The Royal Australian and New Zealand College of Psychiatrists 2016.

Analytical and numerical analysis of finite amplitude Rayleigh-Taylor instability

International Nuclear Information System (INIS)

Meiron, D.I.; Saffman, P.G.

1987-01-01

We summarize the results obtained in the last year. These include a simple model of bubble competition in Rayleigh-Taylor unstable flows which gives results which are in good agreement with experiment. In addition the model has been compared with two dimensional numerical simulations of inviscid Rayleigh-Taylor instability using the cloud-in-cell method. These simulations can now be run into the late time regime and can track the competition of as many as ten bubbles. The improvement in performance over previous applications of the cloud-in-cell approach is due to the application of finite difference techniques designed to handle shock-like structures in the vorticity of the interface which occur at late times. We propose to extend the research carried thus far to Rayleigh-Taylor problems in three dimensional and convergent geometries as well as to two-fluid instabilities in which interface roll-up is observed. Finally we present a budget for the fiscal year 1987-1988. 6 refs

Taylor O(h³) Discretization of ZNN Models for Dynamic Equality-Constrained Quadratic Programming With Application to Manipulators.

Science.gov (United States)

Liao, Bolin; Zhang, Yunong; Jin, Long

2016-02-01

In this paper, a new Taylor-type numerical differentiation formula is first presented to discretize the continuous-time Zhang neural network (ZNN), and obtain higher computational accuracy. Based on the Taylor-type formula, two Taylor-type discrete-time ZNN models (termed Taylor-type discrete-time ZNNK and Taylor-type discrete-time ZNNU models) are then proposed and discussed to perform online dynamic equality-constrained quadratic programming. For comparison, Euler-type discrete-time ZNN models (called Euler-type discrete-time ZNNK and Euler-type discrete-time ZNNU models) and Newton iteration, with interesting links being found, are also presented. It is proved herein that the steady-state residual errors of the proposed Taylor-type discrete-time ZNN models, Euler-type discrete-time ZNN models, and Newton iteration have the patterns of O(h(3)), O(h(2)), and O(h), respectively, with h denoting the sampling gap. Numerical experiments, including the application examples, are carried out, of which the results further substantiate the theoretical findings and the efficacy of Taylor-type discrete-time ZNN models. Finally, the comparisons with Taylor-type discrete-time derivative model and other Lagrange-type discrete-time ZNN models for dynamic equality-constrained quadratic programming substantiate the superiority of the proposed Taylor-type discrete-time ZNN models once again.

Samuel Taylor Coleridge’s

Directory of Open Access Journals (Sweden)

Aslı TEKİNAY

2000-01-01

Full Text Available There is a dark strain which can be traced in the poetry of all the major nineteenth century English romantic poets: a scepticism about the ultimate purpose of man's life, a sense of having lost a metaphysical certainty and faith in the presence of a benevolent power who maintains harmony and order in the universe. Samuel Taylor Coleridge is one of them. In "The Rime of the Ancient Mariner" and "Christabel", he reveals a nightmarish vision of the universe where moral order seems to be replaced by a cosmic "hap".

Characterization of the two-phase Taylor Couette flow

International Nuclear Information System (INIS)

Mehel A; Gabillet B; Djeridi H

2005-01-01

The focus of the present study concerns the effects of a dispersed phase on the structure of a quasi periodic Couette Taylor flow. The two phase flow patterns are investigated experimentally for the Taylor number Ta=780. Small bubbles (0.035 times as small as the gap) are generated by agitation of the upper free surface. Larger bubbles (0.15 times as small as the gap) are produced by injection at the bottom of the apparatus associated with a pressure drop. Void fraction, bubble size and velocity are measured, as well as the azimuthal and axial velocity components of the liquid. A premature transition to turbulence is pointed out and discussed according to the bubble size and their localization in the gap. (authors)

Applicability of Taylor's hypothesis in thermally driven turbulence

Science.gov (United States)

Kumar, Abhishek; Verma, Mahendra K.

2018-04-01

In this paper, we show that, in the presence of large-scale circulation (LSC), Taylor's hypothesis can be invoked to deduce the energy spectrum in thermal convection using real-space probes, a popular experimental tool. We perform numerical simulation of turbulent convection in a cube and observe that the velocity field follows Kolmogorov's spectrum (k-5/3). We also record the velocity time series using real-space probes near the lateral walls. The corresponding frequency spectrum exhibits Kolmogorov's spectrum (f-5/3), thus validating Taylor's hypothesis with the steady LSC playing the role of a mean velocity field. The aforementioned findings based on real-space probes provide valuable inputs for experimental measurements used for studying the spectrum of convective turbulence.

Effect of FLR correction on Rayleigh -Taylor instability of quantum and stratified plasma

International Nuclear Information System (INIS)

Sharma, P.K.; Tiwari, Anita; Argal, Shraddha; Chhajlani, R.K.

2013-01-01

The Rayleigh Taylor instability of stratified incompressible fluids is studied in presence of FLR Correction and quantum effects in bounded medium. The Quantum magneto hydrodynamic equations of the problem are solved by using normal mode analysis method. A dispersion relation is carried out for the case where plasma is bounded by two rigid planes z = 0 and z = h. The dispersion relation is obtained in dimensionless form to discuss the growth rate of Rayleigh Taylor instability in presence of FLR Correction and quantum effects. The stabilizing or destabilizing behavior of quantum effect and FLR correction on the Rayleigh Taylor instability is analyzed. (author)

Rayleigh-Taylor convective overturn in stellar collapse

International Nuclear Information System (INIS)

Bruenn, S.W.; Buchler, J.R.; Livio, M.

1979-01-01

Rayleigh--Taylor convective overturn in collapsing stellar cores is modeled with a one-dimensional parametrization. The results of a numerical hydrodynamic study are very encouraging and indicate that such an overturn could well be a dominant feature in the supernova explosion mechanism

Alfred Rosenberg und die Nordische Gesellschaft – Der „nordische Gedanke“ in Theorie und Praxis

Directory of Open Access Journals (Sweden)

Birgitta Almgren; Jan Hecker-Stampehl; Ernst Piper

2008-12-01

Full Text Available This contribution traces the emergence, Gleichschaltung, expansion and demise of the Nordische Gesellschaft [Nordic Society] with a special focus on its leading protagonist Alfred Rosenberg. In the beginning of the article, the history of ideas and the organisa-tional foundations of the society are being set as a background. In the main part of the text the Nordische Gesellschaft’s activity during the “Third Reich” and under Rosenberg’s auspices is being analysed. Sources used comprise both archival material as well as the NG’s own publications

Frictional Torque Reduction in Taylor-Couette Flows with Riblet-Textured Rotors

Science.gov (United States)

Raayai, Shabnam; McKinley, Gareth

2017-11-01

Inspired by the riblets on the denticles of fast swimming shark species, periodic surface microtextures of different shapes have been studied under laminar and turbulent flow conditions to understand their drag reduction mechanism and to offer guides for designing optimized low-friction bio-inspired surfaces. Various reports over the past four decades have suggested that riblet surfaces can reduce the frictional drag force in high Reynolds number laminar and turbulent flow regimes. Here, we investigate the effect of streamwise riblets on torque reduction in steady flow between concentric cylinders, known as Taylor-Couette Flow. Using 3D printed riblet-textured rotors and a custom-built Taylor-Couette cell which can be mounted on a rheometer we measure the torque on the inner rotor as a function of three different dimensionless parameters; the Reynolds number of the flow, the sharpness of the riblets, and the size of the riblets with respect to the scale of the Taylor-Couette cell. Our experimental results in the laminar viscous flow regime show a reduction in torque up to 10% over a wide range of Reynolds numbers, that is a non-monotonic function of the aspect ratio and independent of Re. However, after transition to the Taylor vortex regime, the modification in torque becomes a function of the Reynolds number, while remaining a non-monotonic function of the aspect ratio. Using finite volume modelling of the geometry we discuss the changes in the Taylor-Couette flow in presence of the riblets compared to the case of smooth rotors and the resulting torque reduction as a function of the parameter space defined above.

Fluid Dynamics And Mass Transfer In Two-Fluid Taylor-Couette Flow

International Nuclear Information System (INIS)

Baier, G.; Graham, M.D.

1998-01-01

The Taylor-Couette instability of a single liquid phase can be used to enhance mass transfer processes such as filtration and membrane separations. We consider here the possibility of using this instability to enhance interphase transport in a two-fluid systems, with a view toward improved liquid-liquid extractions for biotechnology applications. We investigate the centrifugal instability of a pair of radially stratified immiscible liquids in the annular gap between concentric, corotating cylinders: two-fluid Taylor-Couette flow. Experiments show that a two-layer flow with a well-defined interface and Taylor vortices in each phase can be obtained. The experimental results are in good agreement with predictions of inviscid arguments based on a two-phase extension of Rayleigh's criterion, as well as with detailed linear stability calculations. For a given geometry, the most stable configuration occurs for fluids of roughly (exactly in the inviscid limit) equal dynamic viscosities. A number of preliminary mass transfer experiments have also been performed, in the presence of axial counterflow. The onset of Taylor vortices coincides with a clear decrease in the extent of axial dispersion and an increase in the rate of interphase transport, thus suggesting that this flow geometry may provide an effective means for countercurrent chromatographic separations

Ethics, organ donation and tax: a reply to Quigley and Taylor.

Science.gov (United States)

Lippert-Rasmussen, Kasper; Petersen, Thomas Søbirk

2012-08-01

A national opt-out system of post-mortem donation of scarce organs is preferable to an opt-in system. Unfortunately, the former system is not always feasible, and so in a recent JME article we canvassed the possibility of offering people a tax break for opting-in as a way of increasing the number of organs available for donation under an opt-in regime. Muireann Quigley and James Stacey Taylor criticize our proposal. Roughly, Quigley argues that our proposal is costly and, hence, is unlikely to be implemented, while Taylor contests our response to a Titmuss-style objection to our scheme. In response to Quigley, we note that our proposal's main attraction lies in gains not reflected in the figures presented by Quigley and that the mere fact that it is costly does not imply that it is unfeasible. In response to Taylor, we offer some textual evidence in support of our interpretation of Taylor and responds to his favoured interpretation of the Titmuss-style objection that many people seem to want to donate to charities even if they can deduct their donations from their income tax. Finally, we show why our views do not commit us to endorsing a free organ-market.

Number 13 / Part I. Music. 11. Great Contemporary Pianists in Interpretative Dialogue: Alfred Brendel and Murray Perahia

Directory of Open Access Journals (Sweden)

Tudor Brînduşa

2017-03-01

Full Text Available The choice of valuable interpretative versions is highly important for both pianists on their way to performance and teachers in their complex activity of piano training. These become real models of esthetical thinking and artistic inspiration in the approach of a musical work. We shall use Sonata in D minor D 958 by Franz Schubert as an interpretative analysis model in the view of the pianists Alfred Brendel and Murray Perahia.

Alfred Russel Wallace and the road to natural selection, 1844-1858.

Science.gov (United States)

Smith, Charles H

2015-01-01

Conventional wisdom has had it that the naturalist Alfred Russel Wallace and his colleague Henry Walter Bates journeyed to the Amazon in 1848 with two intentions in mind: to collect natural history specimens, and to consider evidential materials that might reveal the causal basis of organic evolution. This understanding has been questioned recently by the historian John van Wyhe, who points out that with regard to the second matter, at least, there appears to be no evidence of a "smoking gun" variety proving it so. In the present essay the circumstances of Wallace's interest in the matter are reviewed, and van Wyhe is taken to task with alternate explanations for the facts he introduces in his argument. The conclusion is that Wallace almost certainly did have the second objective in mind when he left for both the Amazon, and the Far East.

The symbol between ethics and communication in Alfred Schütz

Directory of Open Access Journals (Sweden)

Massimo Vittorio

2018-03-01

Full Text Available This paper focuses on the concept of symbol and tries to out- line its function as a means of communication. In order to describe the communicative qualities of symbol, it is necessary to show its ethical nature. The paper analyses the role symbols play in intersubjective rela- tions, in the construction of the individual’s reality, and in the human ability to attribute meanings and assign functions.The conceptual frame- work for the understanding of what symbol is, how it works, and how it is made is a particular combination of phenomenology and pragma- tism, which lies on the theory of ‘appresentation’, as we can find it in Alfred Schütz’s viewpoint. The paper invites a reflection on the power of symbol, particularly on its power to communicate the incommunicable.

Ekman-Hartmann layer in a magnetohydrodynamic Taylor-Couette flow.

Science.gov (United States)

Szklarski, Jacek; Rüdiger, Günther

2007-12-01

We study magnetic effects induced by rigidly rotating plates enclosing a cylindrical magnetohydrodynamic (MHD) Taylor-Couette flow at the finite aspect ratio HD=10 . The fluid confined between the cylinders is assumed to be liquid metal characterized by small magnetic Prandtl number, the cylinders are perfectly conducting, an axial magnetic field is imposed with Hartmann number Ha approximately 10 , and the rotation rates correspond to Reynolds numbers of order 10(2)-10(3). We show that the end plates introduce, besides the well-known Ekman circulation, similar magnetic effects which arise for infinite, rotating plates, horizontally unbounded by any walls. In particular, there exists the Hartmann current, which penetrates the fluid, turns in the radial direction, and together with the applied magnetic field gives rise to a force. Consequently, the flow can be compared with a Taylor-Dean flow driven by an azimuthal pressure gradient. We analyze the stability of such flows and show that the currents induced by the plates can give rise to instability for the considered parameters. When designing a MHD Taylor-Couette experiment, special care must be taken concerning the vertical magnetic boundaries so that they do not significantly alter the rotational profile.

Numerical study of Taylor bubbles with adaptive unstructured meshes

Science.gov (United States)

Xie, Zhihua; Pavlidis, Dimitrios; Percival, James; Pain, Chris; Matar, Omar; Hasan, Abbas; Azzopardi, Barry

2014-11-01

The Taylor bubble is a single long bubble which nearly fills the entire cross section of a liquid-filled circular tube. This type of bubble flow regime often occurs in gas-liquid slug flows in many industrial applications, including oil-and-gas production, chemical and nuclear reactors, and heat exchangers. The objective of this study is to investigate the fluid dynamics of Taylor bubbles rising in a vertical pipe filled with oils of extremely high viscosity (mimicking the ``heavy oils'' found in the oil-and-gas industry). A modelling and simulation framework is presented here which can modify and adapt anisotropic unstructured meshes to better represent the underlying physics of bubble rise and reduce the computational effort without sacrificing accuracy. The numerical framework consists of a mixed control-volume and finite-element formulation, a ``volume of fluid''-type method for the interface capturing based on a compressive control volume advection method, and a force-balanced algorithm for the surface tension implementation. Numerical examples of some benchmark tests and the dynamics of Taylor bubbles are presented to show the capability of this method. EPSRC Programme Grant, MEMPHIS, EP/K0039761/1.

Process development of starch hydrolysis using mixing characteristics of Taylor vortices.

Science.gov (United States)

Masuda, Hayato; Horie, Takafumi; Hubacz, Robert; Ohmura, Naoto; Shimoyamada, Makoto

2017-04-01

In food industries, enzymatic starch hydrolysis is an important process that consists of two steps: gelatinization and saccharification. One of the major difficulties in designing the starch hydrolysis process is the sharp change in its rheological properties. In this study, Taylor-Couette flow reactor was applied to continuous starch hydrolysis process. The concentration of reducing sugar produced via enzymatic hydrolysis was evaluated by varying operational variables: rotational speed of the inner cylinder, axial velocity (reaction time), amount of enzyme, and initial starch content in the slurry. When Taylor vortices were formed in the annular space, efficient hydrolysis occurred because Taylor vortices improved the mixing of gelatinized starch with enzyme. Furthermore, a modified inner cylinder was proposed, and its mixing performance was numerically investigated. The modified inner cylinder showed higher potential for enhanced mixing of gelatinized starch and the enzyme than the conventional cylinder.

3 CFR - Continuation of the National Emergency With Respect to the Former Liberian Regime of Charles Taylor

Science.gov (United States)

2010-01-01

... to the Former Liberian Regime of Charles Taylor Presidential Documents Other Presidential Documents... of Charles Taylor On July 22, 2004, by Executive Order 13348, the President declared a national... to the former Liberian regime of Charles Taylor, pursuant to the International Emergency Economic...

A petition to Mr Peel: Gideon Mantell and the trial of Hannah Russell.

Science.gov (United States)

Flanagan, R J; Watson, K D

2009-07-01

In the summer of 1826, Hannah Russell was tried for petty treason, viz. the murder of her husband, Benjamin Russell, by poisoning. Their lodger, Daniel Leney, was indicted as her accomplice. The exact circumstances surrounding the death were unclear but Hannah was known to have purchased white arsenic (arsenious oxide). A local surgeon, Thomas Evans, supported at the post-mortem examination by two further surgeons, not only reported severe corrosion of the gastrointestinal tract, but also the recovery of nearly an eighth of an ounce of arsenic from the victim's stomach. Both accused were convicted and sentenced to death. Leney was executed, but Hannah Russell was respited because the trial judge, Sir Robert Graham, had doubts as to a direction he had given to the jury. The surgeon and paleontologist Gideon Mantell took up her case, stressing that death from arsenic could not have taken place as quickly as was alleged and maintaining that the chemical evidence of arsenic poisoning was inconclusive. He gained the support of some eminent chemists and physicians. Subsequently, forensic toxicologists [Sir] Robert Christison and Alfred Swaine Taylor pointed out that Mantell's arguments as to the possible time to death in arsenic poisoning were quite wrong. Moreover, Evans gave details of the analyses he and his colleagues had undertaken to Christison, who pronounced the findings sound, as indeed did Mantell after Evans and his colleagues published details of their investigations in the Sussex Advertiser. Papers in The National Archives show that Hannah was pardoned for the offence for which she was indicted, leaving it open to prefer a lesser charge. That this was never done may have been due to Mantell's campaign, at least in part, but the pardon she did receive was due to the concern of the trial judge as to the implications of the evidence presented at trial.

Student understanding of Taylor series expansions in statistical mechanics

Directory of Open Access Journals (Sweden)

Trevor I. Smith

2013-08-01

Full Text Available One goal of physics instruction is to have students learn to make physical meaning of specific mathematical expressions, concepts, and procedures in different physical settings. As part of research investigating student learning in statistical physics, we are developing curriculum materials that guide students through a derivation of the Boltzmann factor using a Taylor series expansion of entropy. Using results from written surveys, classroom observations, and both individual think-aloud and teaching interviews, we present evidence that many students can recognize and interpret series expansions, but they often lack fluency in creating and using a Taylor series appropriately, despite previous exposures in both calculus and physics courses.

Student understanding of Taylor series expansions in statistical mechanics

Science.gov (United States)

Smith, Trevor I.; Thompson, John R.; Mountcastle, Donald B.

2013-12-01

One goal of physics instruction is to have students learn to make physical meaning of specific mathematical expressions, concepts, and procedures in different physical settings. As part of research investigating student learning in statistical physics, we are developing curriculum materials that guide students through a derivation of the Boltzmann factor using a Taylor series expansion of entropy. Using results from written surveys, classroom observations, and both individual think-aloud and teaching interviews, we present evidence that many students can recognize and interpret series expansions, but they often lack fluency in creating and using a Taylor series appropriately, despite previous exposures in both calculus and physics courses.

Three-dimensional single-mode nonlinear ablative Rayleigh-Taylor instability

International Nuclear Information System (INIS)

Yan, R.; Aluie, H.; Betti, R.; Sanz, J.; Liu, B.; Frank, A.

2016-01-01

The nonlinear evolution of the single-mode ablative Rayleigh-Taylor instability is studied in three dimensions. As the mode wavelength approaches the cutoff of the linear spectrum (short-wavelength modes), it is found that the three-dimensional (3D) terminal bubble velocity greatly exceeds both the two-dimensional (2D) value and the classical 3D bubble velocity. Unlike in 2D, the 3D short-wavelength bubble velocity does not saturate. The growing 3D bubble acceleration is driven by the unbounded accumulation of vorticity inside the bubble. The vorticity is transferred by mass ablation from the Rayleigh-Taylor spikes to the ablated plasma filling the bubble volume

Stand-alone core sensitivity and uncertainty analysis of ALFRED from Monte Carlo simulations

International Nuclear Information System (INIS)

Pérez-Valseca, A.-D.; Espinosa-Paredes, G.; François, J.L.; Vázquez Rodríguez, A.; Martín-del-Campo, C.

2017-01-01

Highlights: • Methodology based on Monte Carlo simulation. • Sensitivity analysis of Lead Fast Reactor (LFR). • Uncertainty and regression analysis of LFR. • 10% change in the core inlet flow, the response in thermal power change is 0.58%. • 2.5% change in the inlet lead temperature the response is 1.87% in power. - Abstract: The aim of this paper is the sensitivity and uncertainty analysis of a Lead-Cooled Fast Reactor (LFR) based on Monte Carlo simulation of sizes up to 2000. The methodology developed in this work considers the uncertainty of sensitivities and uncertainty of output variables due to a single-input-variable variation. The Advanced Lead fast Reactor European Demonstrator (ALFRED) is analyzed to determine the behavior of the essential parameters due to effects of mass flow and temperature of liquid lead. The ALFRED core mathematical model developed in this work is fully transient, which takes into account the heat transfer in an annular fuel pellet design, the thermo-fluid in the core, and the neutronic processes, which are modeled with point kinetic with feedback fuel temperature and expansion effects. The sensitivity evaluated in terms of the relative standard deviation (RSD) showed that for 10% change in the core inlet flow, the response in thermal power change is 0.58%, and for 2.5% change in the inlet lead temperature is 1.87%. The regression analysis with mass flow rate as the predictor variable showed statistically valid cubic correlations for neutron flux and linear relationship neutron flux as a function of the lead temperature. No statistically valid correlation was observed for the reactivity as a function of the mass flow rate and for the lead temperature. These correlations are useful for the study, analysis, and design of any LFR.

Alfred P. Southwick, MDS, DDS: dental practitioner, educator and originator of electrical executions.

Science.gov (United States)

Christen, A G; Christen, J A

2000-11-01

The search for a modern, humane method of criminal execution was triggered by a freak accident which occurred in Buffalo, New York in 1881. Dr. Alfred P. Southwick (a former steam-boat engineer, noted dentist and dental educator) happened to witness an intoxicated man die after he inadvertently touched a live generator terminal. Southwick's initial reaction was shock. Later, as he pondered this tragic event, he concluded that electrocution was, at least, a quick and seemingly painless way to depart from this earth. As his thoughts turned to common methods of capital punishment, Alfred concluded that death by electrocution could become a more humane alternative, as compared with the more grisly methods (e.g., hanging, beheading by guillotine, garroting, suffocation and flaying). Working through the governor of New York and the state legislature, Southwick originated and successfully promoted the passage of laws which mandated electrical executions in New York and in approximately 20 other states. During 1888-1889, Southwick served on the state's three-person Electrical Death Commission, a group who reported that electrical execution was superior to all other methods. On January 1, 1889, the world's first electrical execution law went into effect. On August 6, 1890, William Francis Kemmler, who had murdered his mistress, was the first person to die in the electric chair. However, this public event became an amateurish spectacle: the initial surge of current did not cause Kemmler's immediate death and a second jolt was needed. Those who witnessed this bungled execution were stunned. Graphic and detailed criticism from both the press and the general public ran high. However, Dr. Southwick vigorously continued to support and finally achieve his goal--to humanize capital punishment through the legal use of electrical execution.

Application of the Asymptotic Taylor Expansion Method to Bistable Potentials

Directory of Open Access Journals (Sweden)

Okan Ozer

2013-01-01

Full Text Available A recent method called asymptotic Taylor expansion (ATEM is applied to determine the analytical expression for eigenfunctions and numerical results for eigenvalues of the Schrödinger equation for the bistable potentials. Optimal truncation of the Taylor series gives a best possible analytical expression for eigenfunctions and numerical results for eigenvalues. It is shown that the results are obtained by a simple algorithm constructed for a computer system using symbolic or numerical calculation. It is observed that ATEM produces excellent results consistent with the existing literature.

Approximate expressions for the period of a simple pendulum using a Taylor series expansion

International Nuclear Information System (INIS)

Belendez, Augusto; Marquez, Andres; Ortuno, Manuel; Gallego, Sergi; Arribas, Enrique

2011-01-01

An approximate scheme for obtaining the period of a simple pendulum for large-amplitude oscillations is analysed and discussed. When students express the exact frequency or the period of a simple pendulum as a function of the oscillation amplitude, and they are told to expand this function in a Taylor series, they always do so using the oscillation amplitude as the variable, without considering that if they change the variable (in this paper to the new variable m), a different Taylor series expansion may be performed which is in addition more accurate than previously published ones. Students tend to believe that there is one and only one way of performing a Taylor series expansion of a specific function. The approximate analytical formula for the period is obtained by means of a Taylor expansion of the exact frequency taking into account the Kidd-Fogg formula for the period. This approach based on the Taylor expansion of the frequency about a suitable value converges quickly even for large amplitudes. We believe that this method may be very useful for teaching undergraduate courses on classical mechanics and helping students understand nonlinear oscillations of a simple pendulum.

Approximate expressions for the period of a simple pendulum using a Taylor series expansion

Energy Technology Data Exchange (ETDEWEB)

Belendez, Augusto; Marquez, Andres; Ortuno, Manuel; Gallego, Sergi [Departamento de Fisica, IngenierIa de Sistemas y TeorIa de la Senal, Universidad de Alicante, Apartado 99, E-03080 Alicante (Spain); Arribas, Enrique, E-mail: a.belendez@ua.es [Departamento de Fisica Aplicada, Escuela Superior de IngenierIa Informatica, Universidad de Castilla-La Mancha, Avda de Espana, s/n, E-02071 Albacete (Spain)

2011-09-15

An approximate scheme for obtaining the period of a simple pendulum for large-amplitude oscillations is analysed and discussed. When students express the exact frequency or the period of a simple pendulum as a function of the oscillation amplitude, and they are told to expand this function in a Taylor series, they always do so using the oscillation amplitude as the variable, without considering that if they change the variable (in this paper to the new variable m), a different Taylor series expansion may be performed which is in addition more accurate than previously published ones. Students tend to believe that there is one and only one way of performing a Taylor series expansion of a specific function. The approximate analytical formula for the period is obtained by means of a Taylor expansion of the exact frequency taking into account the Kidd-Fogg formula for the period. This approach based on the Taylor expansion of the frequency about a suitable value converges quickly even for large amplitudes. We believe that this method may be very useful for teaching undergraduate courses on classical mechanics and helping students understand nonlinear oscillations of a simple pendulum.

A numerical study of three-dimensional bubble merger in the Rayleigh endash Taylor instability

International Nuclear Information System (INIS)

Li, X.L.

1996-01-01

The Rayleigh endash Taylor instability arises when a heavy fluid adjacent to a light fluid is accelerated in a direction against the density gradient. Under this unstable configuration, a perturbation mode of small amplitude grows into bubbles of the light fluid and spikes of the heavy fluid. Taylor discovered the steady state motion with constant velocity for a single bubble or periodic bubbles in the Rayleigh endash Taylor instability. Read and Youngs studied the motion of a randomly perturbed fluid interface in the Rayleigh endash Taylor instability. They reported constant acceleration for the overall bubble envelope. Bubble merger is believed to cause the transition from constant velocity to constant acceleration. In this paper, we present a numerical study of this important physical phenomenon. It analyzes the physical process of bubble merger and the relationship between the horizontal bubble expansion and the vertical interface acceleration. A dynamic bubble velocity, beyond Taylor close-quote s steady state value, is observed during the merger process. It is believed that this velocity is due to the superposition of the bubble velocity with a secondary subharmonic unstable mode. The numerical results are compared with experiments. copyright 1996 American Institute of Physics

Advection and Taylor-Aris dispersion in rivulet flow

Science.gov (United States)

Al Mukahal, F. H. H.; Duffy, B. R.; Wilson, S. K.

2017-11-01

Motivated by the need for a better understanding of the transport of solutes in microfluidic flows with free surfaces, the advection and dispersion of a passive solute in steady unidirectional flow of a thin uniform rivulet on an inclined planar substrate driven by gravity and/or a uniform longitudinal surface shear stress are analysed. Firstly, we describe the short-time advection of both an initially semi-infinite and an initially finite slug of solute of uniform concentration. Secondly, we describe the long-time Taylor-Aris dispersion of an initially finite slug of solute. In particular, we obtain the general expression for the effective diffusivity for Taylor-Aris dispersion in such a rivulet, and discuss in detail its different interpretations in the special case of a rivulet on a vertical substrate.

Constructions of legitimacy: the Charles Taylor trial

NARCIS (Netherlands)

Glasius, M.; Meijers, T.

2012-01-01

This article examines the discourses of the prosecution and the defence in the case of Charles Taylor before the Special Court for Sierra Leone. It contributes to current debates about the legitimacy and utility of international criminal justice, which have tended to neglect the examination of

The Rayleigh–Taylor Instability Among the Stars

Indian Academy of Sciences (India)

The Rayleigh–Taylor Instability Among the Stars. Rajaram Nityananda. Rajaram Nityananda works at the School of Liberal. Studies, Azim Premji. University, Bengaluru. Earlier, he spent a decade at the National Centre for Radio. Astrophysics in Pune, and more than two decades at the. Raman Research Institute in.

Mode transition in bubbly Taylor-Couette flow measured by PTV

International Nuclear Information System (INIS)

Yoshida, K; Tasaka, Y; Murai, Y; Takeda, T

2009-01-01

The drag acting to the inner cylinder in Taylor-Couette flow system can be reduced by bubble injection. In this research, relationship between drag reduction and change of vortical structure in a Taylor-Couette flow is investigated by Particle Tracking Velocimetry (PTV). The velocity vector field in the r-z cross section and the bubble concentration in the front view (z-θ plane) are measured. This paper describes the change of vortical structures with bubbles, and the mode transition that is sensitively affected by the bubbles is discussed. The bubbles accumulate in the three parts relative to vortex position by the interaction between bubbles and vortices. The status of bubble's distribution is different depending on position. This difference affects mode transition as its trigger significantly. The presence of bubbles affects the transition from toroidal mode to spiral mode but does not induce the transition from spiral mode to toroidal mode. Further we found that Taylor vortex bifurcates and a pair of vortices coalesces when the flow switches between spiral mode and toroidal mode.

Alfred Donné and Léon Foucault: the first applications of electricity and photography to medical illustration.

Science.gov (United States)

Tobin, William

2006-03-01

The first electric projecting microscope and the first published photomicrographs harnessed recent technological developments to provide improved methods of medical illustration for educational purposes. Both projects were the work of two Frenchmen. The impetus came from the microscopist Dr Alfred Donné (1801-78), discoverer of trichomonas vaginalis and leukaemia. Implementation was primarily by his medical-student assistant, Léon Foucault (1819-68), who later gained fame as a physicist, especially with his pendulum demonstration of the Earth's rotation.

Theoretical and numerical studies of Rayleigh-Taylor instabilities in magnetized plasmas; Etude theorique et numerique des instabilites Rayleigh-Taylor en plasmas magnetises

Energy Technology Data Exchange (ETDEWEB)

Ivanov, A.A

2001-06-01

The instabilities of Rayleigh-Taylor type are considered in the thesis. The topic of the thesis was inspired by recent advances in the physics of plasma compression, especially with the aid of systems like Z-pinch. Rayleigh-Taylor instability (RTI) plays an important role in the evolution of magnetized plasmas in these experiments, as well as in stellar plasmas and classic fluids. For the phenomena concerning the nuclear fusion the RTI is very often the factor limiting the possibility of compression. In the current work we try to examine in detail the characteristic features of the instabilities of this type in order to eliminate their detrimental influence. In this thesis we are studying both the general case of the 'classic' Rayleigh-Taylor instability (in incompressible fluids) and more specific cases of the instabilities of Rayleigh-Taylor type in magnetized plasmas, in the liners or wire array implosions etc. We have studied the influence of the Hall diffusion of magnetic field on the growth rate of the instability. We have obtained in this work a self-similar solution for the widening of the initial profile of the magnetic field and for the wave of the penetration of magnetic field. After that the subsequent evolution of the magnetic field in plasma opening switches (POS) has been examined. We have shown the possibility of the existence of a strong rarefaction wave for collisional and non-collisional cases. This wave can explain the phenomenon of the opening of POS. The effect of the suppression of Rayleigh-Taylor instability by forced oscillations of the boundary between two fluids permits us to propose some ideas for the experiments of inertial fusion. We have considered the general case of the instability, in other words, two incompressible viscous superposed fluids in a gravitational field. We have obtained an exact analytical expression for the growth rate and then we have analyzed the influence of the parameters of external &apos

Disentangling the origins of torque enhancement through wall roughness in Taylor-Couette turbulence

NARCIS (Netherlands)

Zhu, Xiaojue; Verzicco, Roberto; Lohse, Detlef

2017-01-01

Direct numerical simulations (DNS) are performed to analyse the global transport properties of turbulent Taylor-Couette flow with inner rough wall up to Taylor number Ta = 1010. The dimensionless torque Nuω shows an effective scaling of Nuω ∝ Ta0.42±0.01, which is steeper than the ultimate regime

A Taylor weak-statement algorithm for hyperbolic conservation laws

Science.gov (United States)

Baker, A. J.; Kim, J. W.

1987-01-01

Finite element analysis, applied to computational fluid dynamics (CFD) problem classes, presents a formal procedure for establishing the ingredients of a discrete approximation numerical solution algorithm. A classical Galerkin weak-statement formulation, formed on a Taylor series extension of the conservation law system, is developed herein that embeds a set of parameters eligible for constraint according to specification of suitable norms. The derived family of Taylor weak statements is shown to contain, as special cases, over one dozen independently derived CFD algorithms published over the past several decades for the high speed flow problem class. A theoretical analysis is completed that facilitates direct qualitative comparisons. Numerical results for definitive linear and nonlinear test problems permit direct quantitative performance comparisons.

Influence of velocity shear on the Rayleigh-Taylor instability

International Nuclear Information System (INIS)

Guzdar, P.N.; Satyanarayana, P.; Huba, J.D.; Ossakow, S.L.

1982-01-01

The influence of a transverse velocity shear on the Rayleigh-Taylor instability is investigated. It is found that a sheared velocity flow can substantially reduce the growth rate of the Rayleigh-Taylor instability in short wavelength regime (i.e., kL>1 where L is the scale length of the density inhomogeneity), and causes the growth rate to maximize at kL<1.0. Applications of this result to ionospheric phenomena [equatorial spread F (ESF) and ionospheric plasma clouds] are discussed. In particular, the effect of shear could account for, at times, the 100's of km modulation observed on the bottomside of the ESF ionosphere and the km scale size wavelengths observed in barium cloud prompt striation phenomena

Taylor Series-Based Long-Term Creep-Life Prediction of Alloy 617

International Nuclear Information System (INIS)

Yin, Song Nan; Kim, Woo Gon; Kim, Yong Wan; Park, Jae Young; Kim, Soen Jin

2010-01-01

In this study, a Taylor series (T-S) model based on the Arrhenius, McVetty, and Monkman-Grant equations was developed using a mathematical analysis. In order to reduce fitting errors, the McVetty equation was transformed by considering the first three terms of the Taylor series equation. The model parameters were accurately determined by a statistical technique of maximum likelihood estimation, and this model was applied to the creep data of alloy 617. The T-S model results showed better agreement with the experimental data than other models such as the Eno, exponential, and L-M models. In particular, the T-S model was converted into an isothermal Taylor series (IT-S) model that can predict the creep strength at a given temperature. It was identified that the estimations obtained using the converted ITS model was better than that obtained using the T-S model for predicting the long-term creep life of alloy 617

Normalization of the parameterized Courant-Snyder matrix for symplectic factorization of a parameterized Taylor map

International Nuclear Information System (INIS)

Yan, Y.T.

1991-01-01

The transverse motion of charged particles in a circular accelerator can be well represented by a one-turn high-order Taylor map. For particles without energy deviation, the one-turn Taylor map is a 4-dimensional polynomials of four variables. The four variables are the transverse canonical coordinates and their conjugate momenta. To include the energy deviation (off-momentum) effects, the map has to be parameterized with a smallness factor representing the off-momentum and so the Taylor map becomes a 4-dimensional polynomials of five variables. It is for this type of parameterized Taylor map that a mehtod is presented for converting it into a parameterized Dragt-Finn factorization map. Parameterized nonlinear normal form and parameterized kick factorization can thus be obtained with suitable modification of the existing technique

Irregular wall roughness in turbulent Taylor-Couette flow

Science.gov (United States)

Berghout, Pieter; Zhu, Xiaojue; Verzicco, Roberto; Lohse, Detlef; Stevens, Richard

2017-11-01

Many wall bounded flows in nature, engineering and transport are affected by surface roughness. Often, this has adverse effects, e.g. drag increase leading to higher energy costs. A major difficulty is the infinite number of roughness geometries, which makes it impossible to systematically investigate all possibilities. Here we present Direct Numerical Simulations (DNS) of turbulent Taylor-Couette flow. We focus on the transitionally rough regime, in which both viscous and pressure forces contribute to the total wall stress. We investigate the effect of the mean roughness height and the effective slope on the roughness function, ΔU+ . Also, we present simulations of varying Ta (Re) numbers for a constant mean roughness height (kmean+). Alongside, we show the behavior of the large scale structures (e.g. plume ejection, Taylor rolls) and flow structures in the vicinity of the wall.

The Victoria and Alfred Waterfront as playground for Capetonians

Directory of Open Access Journals (Sweden)

Sanette Ferreira

2014-07-01

Full Text Available The paper contributes to the exploration and understanding of the social geographies of public space in the Victoria & Alfred Waterfront (V&AW in Cape Town. The aim is to understand Capetonians’ (visitors and employees perceptions of the V&AW as public, leisure, shopping and working spaces. The appropriate literature on waterfront developments in providing public, working and leisure space is reviewed. Two questionnaire surveys (visitors and employees as well as eight unstructured interviews with important role players in the tourism industry of Cape Town were conducted. Findings revealed the most important reasons for Capetonians to visit or use certain spaces in the V&AW, the public open spaces they liked and how they perceived the V&AW as an inclusive space. The research also sought the respondents’ views on how the certain public spaces can be improved; what new activities and retail shops can be introduced; their opinions about the affordability of restaurants and parking; and how the V&AW can improve to cater for the needs of the Waterfront’s employees. Recommendations are made for making the V&AW more functional and accessible to Capetonians.

A depositional model for the Taylor coal bed, Martin and Johnson counties, eastern Kentucky

Science.gov (United States)

Andrews, W.M.; Hower, J.C.; Ferm, J.C.; Evans, S.D.; Sirek, N.S.; Warrell, M.; Eble, C.F.

1996-01-01

This study investigated the Taylor coal bed in Johnson and Martin counties, eastern Kentucky, using field and petrographic techniques to develop a depositional model of the coal bed. Petrography and chemistry of the coal bed were examined. Multiple benches of the Taylor coal bed were correlated over a 10 km distance. Three sites were studied in detail. The coal at the western and eastern sites were relatively thin and split by thick clastic partings. The coal at the central site was the thickest and unsplit. Two major clastic partings are included in the coal bed. Each represents a separate and distinct fluvial splay. The Taylor is interpreted to have developed on a coastal plain with periodic flooding from nearby, structurally-controlled fluvial systems. Doming is unlikely due to the petrographic and chemical trends, which are inconsistent with modern Indonesian models. The depositional history and structural and stratigraphic setting suggest contemporaneous structural influence on thickness and quality of the Taylor coal bed in this area.

The simultaneous onset and interaction of Taylor and Dean instabilities in a Couette geometry

International Nuclear Information System (INIS)

Hills, C P; Bassom, A P

2005-01-01

The fluid flow between a pair of coaxial circular cylinders generated by the uniform rotation of the inner cylinder and an azimuthal pressure gradient is susceptible to both Taylor and Dean type instabilities. The flow can be characterised by two parameters: a measure of the relative magnitude of the rotation and pressure effects and a non-dimensional Taylor number. Neutral curves associated with each instability can be constructed but it has been suggested that these curves do not cross but rather posses 'kinks'. Our work is based in the small gap, large wavenumber limit and considers the simultaneous onset of Taylor and Dean instabilities. The two linear instabilities interact at exponentially small orders and a consistent, matched asymptotic solution is found across the whole annular domain, identifying five regions of interest: two boundary adjustment regions and three internal critical points. We construct necessary conditions for the concurrent onset of the linear Taylor and Dean instabilities and show that neutral curve crossing is possible

76 FR 24479 - In the Matter of the Taylor Lumber and Treating Superfund Site, Sheridan, Oregon, Amendment to...

Science.gov (United States)

2011-05-02

... ENVIRONMENTAL PROTECTION AGENCY [FRL-9300-9] In the Matter of the Taylor Lumber and Treating... Taylor Lumber and Treating Site, which PWPO was acquiring, in exchange for several obligations related to...-553- 0705. Comments should reference the Taylor Lumber and Treating Superfund Site in Sheridan, Oregon...

The Mantle and Basalt-Crust Interaction Below the Mount Taylor Volcanic Field, New Mexico

Science.gov (United States)

Schrader, Christian M.; Crumpler, Larry S.; Schmidt, Marick E.

2010-01-01

The Mount Taylor Volcanic Field (MTVF) lies on the Jemez Lineament on the southeastern margin of the Colorado Plateau. The field is centered on the Mt. Taylor composite volcano and includes Mesa Chivato to the NE and Grants Ridge to the WSW. MTVF magmatism spans approximately 3.8-1.5 Ma (K-Ar). Magmas are dominantly alkaline with mafic compositions ranging from basanite to hy-basalt and felsic compositions ranging from ne-trachyte to rhyolite. We are investigating the state of the mantle and the spatial and temporal variation in basalt-crustal interaction below the MTVF by examining mantle xenoliths and basalts in the context of new mapping and future Ar-Ar dating. The earliest dated magmatism in the field is a basanite flow south of Mt. Taylor. Mantle xenolith-bearing alkali basalts and basanites occur on Mesa Chivato and in the region of Mt. Taylor, though most basalts are peripheral to the main cone. Xenolith-bearing magmatism persists at least into the early stages of conebuilding. Preliminary examination of the mantle xenolith suite suggests it is dominantly lherzolitic but contains likely examples of both melt-depleted (harzburgitic) and melt-enriched (clinopyroxenitic) mantle. There are aphyric and crystal-poor hawaiites, some of which are hy-normative, on and near Mt. Taylor, but many of the more evolved MTVF basalts show evidence of complex histories. Mt. Taylor basalts higher in the cone-building sequence contain >40% zoned plagioclase pheno- and megacrysts. Other basalts peripheral to Mt. Taylor and at Grants Ridge contain clinopyroxene and plagioclase megacrysts and cumulate-textured xenoliths, suggesting they interacted with lower crustal cumulates. Among the questions we are addressing: What was the chemical and thermal state of the mantle recorded by the basaltic suites and xenoliths and how did it change with time? Are multiple parental basalts (Si-saturated vs. undersaturated) represented and, if so, what changes in the mantle or in the tectonic

Evidence of Rayleigh-Taylor instabilities in tri-layer targets

International Nuclear Information System (INIS)

Galmiche, D.; Holstein, P.A.; Meyer, B.; Rostaing, M.; Wilke, N.

1988-01-01

The results of the experiments carried out on a laser system are reported. The work is performed in order to investigate the problem of target instability under ablative acceleration and to get direct evidence of Rayleigh-Taylor instabilities. Tri-layer experiments assert the validity of X-ray spectroscopy measurements as experimental method to investigate the problem. A mixing zone is evidenced and general trends of mixing development versus target acceleration are coherent with numerical simulations. Results obtained with optical smoothing demonstrate that the apparent mixing is not due to large scale illumination non uniformities. Numerical simulations confirm that Rayleigh-Taylor instability seems to be the dominant process responsible for the mixing. Benefit of time resolved spectroscopy appears attractive and gives a real knowledge of the mixing layer

75 FR 42281 - Continuation of the National Emergency With Respect To the Former Liberian Regime of Charles Taylor

Science.gov (United States)

2010-07-21

... National Emergency With Respect To the Former Liberian Regime of Charles Taylor On July 22, 2004, by... Taylor, pursuant to the International Emergency Economic Powers Act (50 U.S.C. 1701-1706). The President... States constituted by the actions and policies of former Liberian President Charles Taylor and other...

Ruptured peroneal aneurysm after infrapopliteal prosthetic bypass with Taylor patch

Directory of Open Access Journals (Sweden)

Florian Enzmann

Full Text Available Introduction: A 45-year-old mailman underwent an implantation of a femoro-peroneal polytetrafluoroethylene (PTFE bypass with a distal Taylor patch six years prior to admission after two failed autologous reconstructions and extensive fasciotomy. The initial pathology was an acute ischemia due to popliteal entrapment with subsequent popliteal thrombectomy. Report: The patient was examined because of pain, reduction of walking distance and development of a palpable mass at the medial fasciotomy site. A 6-cm pseudoaneurysm with complete disruption of the suture line of the vein patch was discovered and resected. Arterial continuity with a vein interposition graft was established using non-reversed cephalic vein. Conclusion: The etiology of the aneurysm is not entirely clear. One may argue that the fourth revascularization could have been performed with an arm vein instead of a prosthetic graft with the probability of a better long term patency in a young patient. 15 months after the procedure the bypass is patent and the patient is without any symptoms. This complication of a Taylor patch has not been reported before. Keywords: Taylor patch, Pseudoaneurysm, Infrapopliteal bypass

Taylor bubbles at high viscosity ratios: experiments and numerical simulations

Science.gov (United States)

Hewakandamby, Buddhika; Hasan, Abbas; Azzopardi, Barry; Xie, Zhihua; Pain, Chris; Matar, Omar

2015-11-01

The Taylor bubble is a single long bubble which nearly fills the entire cross section of a liquid-filled circular tube, often occurring in gas-liquid slug flows in many industrial applications, particularly oil and gas production. The objective of this study is to investigate the fluid dynamics of three-dimensional Taylor bubble rising in highly viscous silicone oil in a vertical pipe. An adaptive unstructured mesh modelling framework is adopted here which can modify and adapt anisotropic unstructured meshes to better represent the underlying physics of bubble rising and reduce computational effort without sacrificing accuracy. The numerical framework consists of a mixed control volume and finite element formulation, a `volume of fluid'-type method for the interface-capturing based on a compressive control volume advection method, and a force-balanced algorithm for the surface tension implementation. Experimental results for the Taylor bubble shape and rise velocity are presented, together with numerical results for the dynamics of the bubbles. A comparison of the simulation predictions with experimental data available in the literature is also presented to demonstrate the capabilities of our numerical method. EPSRC Programme Grant, MEMPHIS, EP/K0039761/1.

Editorial: Howard Taylor Ricketts

Directory of Open Access Journals (Sweden)

Facultad de Medicina Revista

1941-05-01

Full Text Available Howard Taylor Ricketts nació en Findlay (Ohio el 9 de febrero de 1871. Pasó su niñez en Nebraska, recibió su título de bachiller en la Universidad de ese Estado, en 1894 y se graduó de médico en Northwestern University, en 1897. Hizo su internado en el Cook-County de Chicago. Practicó estdios especiales de dermatología en el Rush Medical College durante dos años. En 1900 contrajo matrimonio con Myra Tubbs, inteligente mujer que colaboró en sus trabajos con rara devoción, ardiente interés y constante estímulo.

Accelerating medical innovation at USC: realizing the dream of Alfred E. Mann.

Science.gov (United States)

Gosset, Nathalie; Lasch, Jonathan G

2012-07-01

Alfred E. Mann's vision is to create organizations that will help medical innovations born in academic environments evolve into commercially fit solutions, without the risk of being abandoned under the financial pressures early stage start-ups often experience. In 1998, Mann worked with Stephen Sample, president of USC, to create the first AMI for Biomedical Engineering, an organization fueled by an endowment valued at approximately US$160 million today. Technology-acceleration centers come in different flavors. AMI USC's recipe has evolved since its creation, with edits that incorporate lessons learned and improvements brought by its expanding network of talented resource people. Its 15-member staff, consisting of three-fourths industry professionals, includes seasoned generalists and specialists in medical technology commercialization. Although the support varies with each invention, some recurring ingredients weave into the AMI approach to accelerating medical innovation.

Spread F bubbles - Nonlinear Rayleigh-Taylor mode in two dimensions

Science.gov (United States)

Hudson, M. K.

1978-01-01

The paper discusses long-wavelength developed bottomside spread F which has been attributed to the Rayleigh-Taylor instability. The nonlinear saturation amplitude and the k spectrum of the inertia-dominated Rayleigh-Taylor instability is found in two directions: east-west and vertical. As in the collisional case (Chaturvedi and Ossakow, 1977), the dominant nonlinearity is found to be two-dimensional. It is found that the linearly most unstable modes, which are primarily horizontal, saturate by the nonlinear generation of vertical spatial harmonics. The harmonics are damped by diffusion or recombination. The resulting amplitude spectrum indicates that bubbles are vertically elongated in both inertial and collisional regimes.

Observation of Rayleigh-Taylor-like structures in a laser-accelerated foil

International Nuclear Information System (INIS)

Whitlock, R.R.; Emery, M.H.; Stamper, J.A.; McLean, E.A.; Obenschain, S.P.; Peckerar, M.C.

1984-01-01

Laser-accelerated targets have been predicted to be subject to the Rayleigh-Taylor hydrodynamic instability. The development of the instability was studied by introducing mass thickness variations in foil targets and observing the development of the target nonuniformities by side-on flash x radiography. Observations were made of target structures and mass redistribution effects which resemble Rayleigh-Taylor bubbles and spikes, including not only advanced broadening of the spike tips on the laser-irradiated side of the foil but also projections of mass on the unirradiated side. The observations compare well with numerical simulations

78 FR 43751 - Continuation of the National Emergency With Respect to the Former Liberian Regime of Charles Taylor

Science.gov (United States)

2013-07-19

... National Emergency With Respect to the Former Liberian Regime of Charles Taylor On July 22, 2004, by... regime of Charles Taylor pursuant to the International Emergency Economic Powers Act (50 U.S.C. 1701-1706... constituted by the actions and policies of former Liberian President Charles Taylor and other persons, in...

Wall Shear Rates in Taylor Vortex Flow

Czech Academy of Sciences Publication Activity Database

Sobolík, V.; Jirout, T.; Havlica, Jaromír; Kristiawan, M.

2011-01-01

Roč. 4, č. 3 (2011), s. 25-31 ISSN 1735-3572 Grant - others:ANR:(FR) ANR-08-BLAN-0184-01 Institutional research plan: CEZ:AV0Z40720504 Keywords : taylor-couette flow * electrodiffusion diagnostics * membrane reactors Subject RIV: CI - Industrial Chemistry, Chemical Engineering http://www.jafmonline.net/modules/journal/journal_browse.php?EJjid=13

Alfred Kubin: un sognatore a vita

Directory of Open Access Journals (Sweden)

Simona Argentieri

2010-12-01

Full Text Available Il saggio considera l’opera grafica e narrativa di Alfred Kubin (1877-1959, artista boemo ai margini del movimento espressionista, che con i suoi scritti fantastici e i suoi disegni onirici ha suscitato infiniti spunti di interpretazione psicologica. Secondo l’autrice, la qualità e l’originalità delle creazioni di Kubin non si può però cercare nella decifrazione simbolica dei contenuti, considerandoli a priori spie di materiali psichici profondi sgorgati dall’inconscio. Più interessante semmai tentare di far ordine tra i diversi livelli di intenzionalità e di coscienza che si intrecciano nelle sue creazioni. Freud e Kubin sono contemporanei; vivono entrambi nel cuore della mitteleuropa, parlano la stessa lingua, respirano lo stesso fervido clima culturale, ma si sono reciprocamente ignorati. Le loro differenze sono irriducibili fin dal piano teorico, poiché per Freud il sogno è solo la via -sia pure regia- per scrutare l’inconscio, ma è in sé materia bruta, ipoevoluta. Per Kubin invece è un fenomeno ipervalutato, un principio creativo autonomo e superiore, quasi metafisico. E’ invece profondamente aderente al più moderno spirito psicoanalitico il metodo secondo il quale Kubin dice come vorrebbe essere guardato: “Il vero fruitore, così come io lo desidero, dovrà guardare i miei fogli non solo apprezzandoli e criticandoli, ma come animato da sensazioni segrete, dovrebbe rivolgere la sua attenzione anche alla ricchissima camera oscura della propria coscienza onirica.” Cioè, detto nei nostri più attuali termini psicoanalitici, lo “spazio transizionale” dell’opera è abitato da artista e fruitore, che vi attribuiscono significati potenzialmente infiniti, più o meno condivisi, ma che comunque nell’incontro con l’altro acquistano senso attivando circuiti sinestetici affettivi e cognitivi.

The aerial view of Cordoba drawn by Alfred Guesdon in 1853

Directory of Open Access Journals (Sweden)

Antonio Gámiz Gordo

2018-02-01

Full Text Available The aerial views by Alfred Guesdon are considered works of special interest due to their quality and beauty. These drawings are a faithful portrait of the great cities of the period, and a mystery in terms of their creation. After reviewing some of the aerial drawings of the mid-19th century, the author considers undocumented hypotheses regarding the relationship of Charles Clifford to the drawings by Guesdon of Spanish cities, and the issues related to their elaboration by means of plans, photographs and hot-air balloons. Some light is shed on this matter thanks to the unpublished drawing of the city of Cordoba (1853, whose accuracy is evident when compared to a city plan drawn by Montis (1851. A journey through the city of Cordoba and its landmarks proves the documentary value of the drawing by Guesdon, who knew how to combine traditional drawing skills with the latest technical advances of his time.

Rayleigh-Taylor mixing with time-dependent acceleration

Science.gov (United States)

Abarzhi, Snezhana

2016-10-01

We extend the momentum model to describe Rayleigh-Taylor (RT) mixing driven by a time-dependent acceleration. The acceleration is a power-law function of time, similarly to astrophysical and plasma fusion applications. In RT flow the dynamics of a fluid parcel is driven by a balance per unit mass of the rates of momentum gain and loss. We find analytical solutions in the cases of balanced and imbalanced gains and losses, and identify their dependence on the acceleration exponent. The existence is shown of two typical regimes of self-similar RT mixing-acceleration-driven Rayleigh-Taylor-type and dissipation-driven Richtymer-Meshkov-type with the latter being in general non-universal. Possible scenarios are proposed for transitions from the balanced dynamics to the imbalanced self-similar dynamics. Scaling and correlations properties of RT mixing are studied on the basis of dimensional analysis. Departures are outlined of RT dynamics with time-dependent acceleration from canonical cases of homogeneous turbulence as well as blast waves with first and second kind self-similarity. The work is supported by the US National Science Foundation.

Alfred Loisy, más allá del ruido y del humo. «Qui perdiderit animan suam salvam faciet eam (Marc, VIII, 35

Directory of Open Access Journals (Sweden)

Robles Muñoz, Cristobal

2007-12-01

Full Text Available Loisy and the modernism were identified during years. This work tries, beyond the noise and the smoke, to contribute not to loose in the forgetfulness neither the person nor the reasons of Alfred Loisy, one of the most affected by the modernist crisis. We have resorted mainly to his Mémoires. Loisy did not need to hope years to receive the tribute that deserves a person who has not betrayed itself.Loisy y el modernismo se identicaron durante años. Este trabajo pretende, más allá del ruido y del humo, contribuir a que no se pierda en el olvido ni la persona ni las razones de Alfred Loisy, uno de los más afectados por la crisis modernista. Hemos recurrido sobre todo a a sus Mémoires. Loisy no necesitó esperar años para recibir el homenaje que merece una persona que no se ha traicionado.

76 FR 43799 - Continuation of the National Emergency With Respect to the Former Liberian Regime of Charles Taylor

Science.gov (United States)

2011-07-21

...--Continuation of the National Emergency With Respect to the Former Liberian Regime of Charles Taylor #0; #0; #0... Continuation of the National Emergency With Respect to the Former Liberian Regime of Charles Taylor On July 22... of Charles Taylor, pursuant to the International Emergency Economic Powers Act (50 U.S.C. 1701-1706...

Boundary effects and the onset of Taylor vortices

Science.gov (United States)

Rucklidge, A. M.; Champneys, A. R.

2004-05-01

It is well established that the onset of spatially periodic vortex states in the Taylor-Couette flow between rotating cylinders occurs at the value of Reynolds number predicted by local bifurcation theory. However, the symmetry breaking induced by the top and bottom plates means that the true situation should be a disconnected pitchfork. Indeed, experiments have shown that the fold on the disconnected branch can occur at more than double the Reynolds number of onset. This leads to an apparent contradiction: why should Taylor vortices set in so sharply at the Reynolds number predicted by the symmetric theory, given such large symmetry-breaking effects caused by the boundary conditions? This paper offers a generic explanation. The details are worked out using a Swift-Hohenberg pattern formation model that shares the same qualitative features as the Taylor-Couette flow. Onset occurs via a wall mode whose exponential tail penetrates further into the bulk of the domain as the driving parameter increases. In a large domain of length L, we show that the wall mode creates significant amplitude in the centre at parameter values that are O( L-2) away from the value of onset in the problem with ideal boundary conditions. We explain this as being due to a Hamiltonian Hopf bifurcation in space, which occurs at the same parameter value as the pitchfork bifurcation of the temporal dynamics. The disconnected anomalous branch remains O(1) away from the onset parameter since it does not arise as a bifurcation from the wall mode.

Identification of Dynamic Loads Based on Second-Order Taylor-Series Expansion Method

OpenAIRE

Li, Xiaowang; Deng, Zhongmin

2016-01-01

A new method based on the second-order Taylor-series expansion is presented to identify the structural dynamic loads in the time domain. This algorithm expresses the response vectors as Taylor-series approximation and then a series of formulas are deduced. As a result, an explicit discrete equation which associates system response, system characteristic, and input excitation together is set up. In a multi-input-multi-output (MIMO) numerical simulation study, sinusoidal excitation and white no...

Search for Rayleigh-Taylor instability in laser irradiated layered thin foil targets

International Nuclear Information System (INIS)

Kilkenny, J.D.; Hares, J.D.; Rumsby, P.T.

1980-01-01

An experiment to measure the Rayleigh-Taylor instability at the vacuum-ablation surface of laser irradiated layered targets by time resolved x-ray spectroscopy is described. The time taken to burn through a layer of material is measured to be the same for massive targets as for thin foil accelerating targets. It is inferred that the thin foil targets might be Rayleigh-Taylor stable despite the values of γtauapproximately equal to15 calculated from classical theory. (author)

Effect of weak geometrical forcing on the stability of Taylor-vortex flow

International Nuclear Information System (INIS)

Pan Xiaolong; Khayat, Roger E

2008-01-01

Linear stability analysis of fully developed axisymmetric steady and spatially modulated Taylor-Couette flow is carried out in the narrow-gap limit. The inner cylinder is sinusoidally modulated and rotating, while the outer cylinder is straight and at rest. The modulation amplitude is assumed to be small, and the base steady flow is determined using a regular perturbation expansion of the flow field coupled to a variable-step finite-difference scheme. The disturbance flow equations are derived within the framework of Floquet theory and solved using a nonlinear two-point boundary-value approach. In contrast to unforced Taylor-Couette flow, only vortical base flow is possible in the forced case. It is found that the forcing tends to generally destabilize the base flow, especially around the critical point. Both the critical Taylor number and wavenumber are found to decrease essentially linearly with modulation amplitude.

Effect of magnetic field on Rayleigh-Taylor instability of two superposed fluids

International Nuclear Information System (INIS)

Sharma, P K; Tiwari, Anita; Chhajlani, R K

2012-01-01

The effect of two dimensional magnetic field on the Rayleigh-Taylor (R-T) instability in an incompressible plasma is investigated to include simultaneously the effects of suspended particles and the porosity of the medium. The relevant linearized perturbation equations have been solved. The explicit expression of the linear growth rate is obtained in the presence of fixed boundary conditions. A stability criterion for the medium is derived and discussed the Rayleigh Taylor instabilities in different configurations. It is found that the basic Rayleigh-Taylor instability condition is modified by the presence of magnetic field, suspended particles and porosity of the medium. In case of an unstable R-T configuration, the magnetic field has a stabilizing effect on the system. It is also found that the growth rate of an unstable R-T mode decreases with increasing relaxation frequency thereby showing a stabilizing influence on the R-T configuration.

Reliability, validity and description of timed performance of the Jebsen-Taylor Test in patients with muscular dystrophies.

Science.gov (United States)

Artilheiro, Mariana Cunha; Fávero, Francis Meire; Caromano, Fátima Aparecida; Oliveira, Acary de Souza Bulle; Carvas, Nelson; Voos, Mariana Callil; Sá, Cristina Dos Santos Cardoso de

2017-12-08

The Jebsen-Taylor Test evaluates upper limb function by measuring timed performance on everyday activities. The test is used to assess and monitor the progression of patients with Parkinson disease, cerebral palsy, stroke and brain injury. To analyze the reliability, internal consistency and validity of the Jebsen-Taylor Test in people with Muscular Dystrophy and to describe and classify upper limb timed performance of people with Muscular Dystrophy. Fifty patients with Muscular Dystrophy were assessed. Non-dominant and dominant upper limb performances on the Jebsen-Taylor Test were filmed. Two raters evaluated timed performance for inter-rater reliability analysis. Test-retest reliability was investigated by using intraclass correlation coefficients. Internal consistency was assessed using the Cronbach alpha. Construct validity was conducted by comparing the Jebsen-Taylor Test with the Performance of Upper Limb. The internal consistency of Jebsen-Taylor Test was good (Cronbach's α=0.98). A very high inter-rater reliability (0.903-0.999), except for writing with an Intraclass correlation coefficient of 0.772-1.000. Strong correlations between the Jebsen-Taylor Test and the Performance of Upper Limb Module were found (rho=-0.712). The Jebsen-Taylor Test is a reliable and valid measure of timed performance for people with Muscular Dystrophy. Copyright © 2017 Associação Brasileira de Pesquisa e Pós-Graduação em Fisioterapia. Publicado por Elsevier Editora Ltda. All rights reserved.

Liz Taylor : minu van Gogh pole natsidele kuulunud

Index Scriptorium Estoniae

2004-01-01

Elizabeth Taylor palus kohtult otsust, et talle kuuluvat 15 miljonit dollarit maksvat Vincent van Goghi maali "Vaade Saint-Remy varjupaigale" pole natsid Margarete Mauthneri juudiperekonna käest vägivaldselt ära võtnud. E. Taylori isa ostis maali 1963. a. Londonis oksjonilt

Taylor vortices in the flow between two coaxial cylinders one of which has a step change in radius

International Nuclear Information System (INIS)

Raju, V R K

2014-01-01

A numerical study of the flow between two coaxial cylinders, where one of the cylinders has a step change in radius, is carried out. The inner cylinder rotates and the outer cylinder is stationary. Computation is restricted to axisymmetric motion since instability in flow between coaxial cylinders is found to first occur in the form of axisymmetric Taylor vortices. In the presence of a step, Taylor vortices are found to appear first in the region where the gap between the cylinders is larger and approximately when the local Taylor number in this region reaches the critical Taylor number for onset of instability. Subsequently, Taylor vortices appear in the region where the gap is narrower, and when the local Taylor number in that region exceeds the critical Taylor number. The Taylor vortices have inward flow at a stationary end plate, and outward flow at an end plate which rotates with the same angular velocity as the inner cylinder. Similar results were obtained by Sprague et al (2008 Phys. Fluids 20 014102) for a step on inner cylinder configuration. The step functions as another end plate, if the step size is large. Whereas, it has no effect, if the step size is small. In most situations, these determine whether the number of Taylor vortices in the wide and narrow gap regions is even or odd. When the end plates rotate synchronously, but at a different speed from the inner cylinder, a change from even to odd or odd to even number of vortices in each region occurs at certain rotation rates of the end plates by sudden appearance or disappearance of a vortex at the end of the column. For a certain range of rotation rates of the end plates, the total number of vortices in the entire fluid column is odd, although the end conditions are symmetrical. (paper)

Predictability of Rayleigh-Taylor instability

International Nuclear Information System (INIS)

Viecelli, J.A.

1986-01-01

Numerical experiments modeling the Rayleigh Taylor instability are carried out using a two-dimensional incompressible Eulerian hydrodynamic code VFTS. The method of integrating the Navier-Stokes equations including the viscous terms is similar to that described in Kim and Moin, except that Lagrange particles have been added and provision for body forces is given. The Eulerian method is 2nd order accurate in both space and time, and the Poisson equation for the effective pressure field is solved exactly at each time step using a cyclic reduction method. 3 refs., 3 figs

Examining the Extent and Nature of Online Learning in American K-12 Education: The Research Initiatives of the Alfred P. Sloan Foundation

Science.gov (United States)

Picciano, Anthony G.; Seaman, Jeff; Shea, Peter; Swan, Karen

2012-01-01

In 1992, the Alfred P. Sloan Foundation began its "Anytime, Anyplace Learning Program", the purpose of which was to explore educational alternatives for people who wanted to pursue an education via Internet technology. Part of this grant activity was a research award to the Babson College Survey Research Group to examine online learning in…

Taylorism, Tylerism, and Performance Indicators: Defending the Indefensible?

Science.gov (United States)

Helsby, Gill; Saunders, Murray

1993-01-01

Explores the antecedents to the growing interest in the use of educational performance indicators. Discusses this issue in relation to the work of economist F. W. Taylor and evaluator Ralph Tyler. Describes a five-year project that demonstrates the promise of teacher-developed performance indicators. (CFR)

Taylor dispersion of colloidal particles in narrow channels

NARCIS (Netherlands)

Sane, J.; Padding, J.T.; Louis, A.A.

2015-01-01

Special issue in Honor of Jean-Pierre Hansen We use a mesoscopic particle-based simulation technique to study the classic convection-diffusion problem of Taylor dispersion for colloidal discs in confined flow. When the disc diameter becomes non-negligible compared to the diameter of the pipe, there

On the validity of Taylor's hypothesis for wall-bounded flows

International Nuclear Information System (INIS)

Piomelli, U.; Balint, J.; Wallace, J.M.

1989-01-01

The results of large eddy simulation (LES) of the Navier--Stokes equations are used to evaluate the validity of Taylor's hypothesis of frozen turbulence, which states that the time derivative of some instantaneous quantity is proportional to its derivative in the streamwise direction, for incompressible plane channel flow. Time and space derivatives in the streamwise direction of the velocity components are, in fact, found to be well correlated. Root-mean-square fluctuations of the terms in Taylor's hypothesis also support the validity of this hypothesis above the buffer layer. The good agreement between LES and experimental results indicates that errors in the evaluation of derivatives in the streamwise direction are due mostly to insufficient resolution

Synchrotron radiation microtomography of Taylor bubbles in capillary two-phase flow

Energy Technology Data Exchange (ETDEWEB)

Boden, Stephan [Helmholtz-Zentrum Dresden - Rossendorf (HZDR), Institute of Fluid Dynamics, P.O. Box 510119, Dresden (Germany); Santos Rolo, Tomy dos; Baumbach, Tilo [Karlsruhe Institute of Technology (KIT), Institute for Photon Science and Synchrotron Radiation (IPS), Eggenstein-Leopoldshafen (Germany); Hampel, Uwe [Helmholtz-Zentrum Dresden - Rossendorf (HZDR), Institute of Fluid Dynamics, P.O. Box 510119, Dresden (Germany); Technische Universitaet Dresden (TUD), AREVA Endowed Chair of Imaging Techniques in Energy and Process Engineering, Dresden (Germany)

2014-07-15

We report on a study to measure the three-dimensional shape of Taylor bubbles in capillaries using synchrotron radiation in conjunction with ultrafast radiographic imaging. Moving Taylor bubbles in 2-mm round and square capillaries were radiographically scanned with an ultrahigh frame rate of up to 36,000 fps and 5.6-μm pixel separation. Consecutive images were properly processed to yield 2D transmission radiographs of high contrast-to-noise ratio. Application of 3D tomographic image reconstruction disclosed the 3D bubble shape. The results provide a reference data base for development of sophisticated interface resolving CFD computations. (orig.)

Synchrotron radiation microtomography of Taylor bubbles in capillary two-phase flow

Science.gov (United States)

Boden, Stephan; dos Santos Rolo, Tomy; Baumbach, Tilo; Hampel, Uwe

2014-07-01

We report on a study to measure the three-dimensional shape of Taylor bubbles in capillaries using synchrotron radiation in conjunction with ultrafast radiographic imaging. Moving Taylor bubbles in 2-mm round and square capillaries were radiographically scanned with an ultrahigh frame rate of up to 36,000 fps and 5.6-µm pixel separation. Consecutive images were properly processed to yield 2D transmission radiographs of high contrast-to-noise ratio. Application of 3D tomographic image reconstruction disclosed the 3D bubble shape. The results provide a reference data base for development of sophisticated interface resolving CFD computations.

Synchrotron radiation microtomography of Taylor bubbles in capillary two-phase flow

International Nuclear Information System (INIS)

Boden, Stephan; Santos Rolo, Tomy dos; Baumbach, Tilo; Hampel, Uwe

2014-01-01

We report on a study to measure the three-dimensional shape of Taylor bubbles in capillaries using synchrotron radiation in conjunction with ultrafast radiographic imaging. Moving Taylor bubbles in 2-mm round and square capillaries were radiographically scanned with an ultrahigh frame rate of up to 36,000 fps and 5.6-μm pixel separation. Consecutive images were properly processed to yield 2D transmission radiographs of high contrast-to-noise ratio. Application of 3D tomographic image reconstruction disclosed the 3D bubble shape. The results provide a reference data base for development of sophisticated interface resolving CFD computations. (orig.)

The Contribution of F.W. Taylor to Industrial and Organizational Psychology

Directory of Open Access Journals (Sweden)

E. C. Thomas

1982-11-01

In die artikel word getoon dat F.W. Taylor die erkende "vader van wetenskaplike bestuur" ook erkenning behoort te geniet as grondlegger van die Bedryf en -organisasiesielkunde. Sy werk op die terreine van prestasiemotivering en tevredenheid, opleiding, plasing van werkers, bestuurs- en organisasieontwikkeling en arbeidsverhoudinge het waarskynlik die werk van erkende sielkundiges op hierdie gebiede vooruitgeloop, of grondslag daarvoor gelê. Daar word tot die slotsom gekom dat alhoewel Taylor nie 'n opgeleide sielkundige was nie, hy en sy kollegas erkenning moet kry vir die praktiese implimentering van die beginsels en teorieë van die moderne Bedryf- en Organisasiesielkunde.

Taylor Series Trajectory Calculations Including Oblateness Effects and Variable Atmospheric Density

Science.gov (United States)

Scott, James R.

2011-01-01

Taylor series integration is implemented in NASA Glenn's Spacecraft N-body Analysis Program, and compared head-to-head with the code's existing 8th- order Runge-Kutta Fehlberg time integration scheme. This paper focuses on trajectory problems that include oblateness and/or variable atmospheric density. Taylor series is shown to be significantly faster and more accurate for oblateness problems up through a 4x4 field, with speedups ranging from a factor of 2 to 13. For problems with variable atmospheric density, speedups average 24 for atmospheric density alone, and average 1.6 to 8.2 when density and oblateness are combined.

Insulin diffusion and self-association characterized by real-time UV imaging and Taylor dispersion analysis

DEFF Research Database (Denmark)

Jensen, Sabrine S; Jensen, Henrik; Cornett, Claus

2014-01-01

, self-association, and apparent size of insulin were further characterized by Taylor dispersion analysis, size exclusion chromatography, and dynamic light scattering. At low insulin concentrations and pH 3.0, the hydrodynamic radius of insulin was determined by Taylor dispersion analysis to 1.5±0.1nm...

The Archaeology and Pottery of Nazca, Peru. Alfred L. Kroeber's 1926 Expedition. Alfred L Kroeber and Donald Collier. edited by Patrick H. Carmichael, Walnut Creek: Altamira Press, 1998

Directory of Open Access Journals (Sweden)

David L. Browman

2000-05-01

Full Text Available This volume is the much delayed publication of the results of the Second Marshall Field Archaeological Expedition to Peru in 1926, sponsored by the Field Museum of Natural History in Chicago, and con­ducted by Alfred Kroeber(1876-1960. It contains some useful short "history of the discipline" remarks both in the preface by Carmichael and in the draft introduction to the original manuscript by Kroeber and Collier. Donald Collier (1911-1995, was curator at the Field Museum from 1941 to 1976, and was working with Kroeber in the late 1950s to help bring the report out, but work stopped with Kroeber's death in 1960. Carmichael ran across the unfinished manuscript in the Field Museum in 1986 while do­ing research on the Nazca assemblages as a graduate student, and with Collier's permission and assis­tance, reassembled the component parts and edited the manuscript for publication.

Effect of magnetic field on the Rayleigh Taylor instability of rotating and stratified plasma

International Nuclear Information System (INIS)

Sharma, PK; Tiwari, Anita; Argal, Shraddha

2017-01-01

In the present study the effect of magnetic field and rotation have been carried out on the Rayleigh Taylor instability of conducting and rotating plasma, which is assumed to be incompressible and confined between two rigid planes z = 0 and z = h. The dispersion relation of the problem is obtained by solving the basic MHD equations of the problem with the help normal mode technique and appropriate boundary conditions. The dispersion relation of the medium is analysed and the effect of magnetic field and angular velocity (rotation effect) have been examined on the growth rate of Rayleigh Taylor instability. It is found that the magnetic field and angular velocity (rotation effect) have stabilizing influence on the Rayleigh Taylor instability. (paper)

Modeling Taylor series approximations for prompt neutron kinetics with lab view simulations

International Nuclear Information System (INIS)

Adzri, E. P.

2012-09-01

The reactor point kinetics equations have been subjected to intense research in an effort to find simple yet accurate numerical solutions methods. The equations are very stiff numerically, meaning that there is a wide variation in the decay constants, so that using a particular time step in the numerical solution may provide sufficient accuracy for the group, but not for another. Several solutions techniques have been presented on the point kinetics equations with varying degrees of complexity. These include Power Series Solutions, CORE, PCA, Genapol and Taylor series methods. In this research, algorithms were developed based on the first and second order Taylor series expansion and simulated in LabVIEW to solve the Reactor Point Kinetics equations using block diagram nodes implemented within stacked sequences. The algorithms developed were fast,accurate and simple to code. Several reactivity insertions were used to simulate the change in neutron population with time. The LabVIEW- Taylor series solutions were compared with other solution techniques such as Power Series Solutions, CORE, PCA, Genapol and McMahon and Pierson's Taylor series approximation. The results of LabVIEW-Taylor series technique used by McMahon and Pearson The LabVIEW-implemented techniques were found to agree very well with these other methods. At 1x10 -8 s the neutron population was 1.000220 neutrons / cm 3 , at 1 x 10 -2 s it was 2.007681 neutrons / cm 3 and at 1x10 -1 s it was 2.075317 neutrons / cm 3 ; same results reported by Genapol for a fast reactor, it produced good and accurate results and compared very favorably with other methods found in the literature. Using much smaller time steps to the order or 10 -8 s commensurate with fast reactor parameters also produced very satisfactory results, indicating that the LabVIEW-based Taylor series technique is suitable for simulating the kinetics of fast reactors as well as thermal reactors. Algorithms developed that included second order terms

Rayleigh-Taylor mixing with space-dependent acceleration

Science.gov (United States)

Abarzhi, Snezhana

2016-11-01

We extend the momentum model to describe Rayleigh-Taylor (RT) mixing driven by a space-dependent acceleration. The acceleration is a power-law function of space coordinate, similarly to astrophysical and plasma fusion applications. In RT flow the dynamics of a fluid parcel is driven by a balance per unit mass of the rates of momentum gain and loss. We find analytical solutions in the cases of balanced and imbalanced gains and losses, and identify their dependence on the acceleration exponent. The existence is shown of two typical sub-regimes of self-similar RT mixing - the acceleration-driven Rayleigh-Taylor-type mixing and dissipation-driven Richtymer-Meshkov-type mixing with the latter being in general non-universal. Possible scenarios are proposed for transitions from the balanced dynamics to the imbalanced self-similar dynamics. Scaling and correlations properties of RT mixing are studied on the basis of dimensional analysis. Departures are outlined of RT dynamics with space-dependent acceleration from canonical cases of homogeneous turbulence as well as blast waves with first and second kind self-similarity. The work is supported by the US National Science Foundation.

Using Taylor Expansions to Prepare Students for Calculus

Science.gov (United States)

Lutzer, Carl V.

2011-01-01

We propose an alternative to the standard introduction to the derivative. Instead of using limits of difference quotients, students develop Taylor expansions of polynomials. This alternative allows students to develop many of the central ideas about the derivative at an intuitive level, using only skills and concepts from precalculus, and…

Taylor dispersion on a fractal

International Nuclear Information System (INIS)

Mazo, R.M.

1998-01-01

Taylor dispersion is the greatly enhanced diffusion in the direction of a fluid flow caused by ordinary diffusion in directions orthogonal to the flow. It is essential that the system be bounded in space in the directions orthogonal to the flow. We investigate the situation where the medium through which the flow occurs has fractal properties so that diffusion in the orthogonal directions is anomalous and non-Fickian. The effective diffusion in the flow direction remains normal; its width grows proportionally with the time. However, the proportionality constant depends on the fractal dimension of the medium as well as its walk dimension. (author)

Study of three-dimensional Rayleigh--Taylor instability in compressible fluids through level set method and parallel computation

International Nuclear Information System (INIS)

Li, X.L.

1993-01-01

Computation of three-dimensional (3-D) Rayleigh--Taylor instability in compressible fluids is performed on a MIMD computer. A second-order TVD scheme is applied with a fully parallelized algorithm to the 3-D Euler equations. The computational program is implemented for a 3-D study of bubble evolution in the Rayleigh--Taylor instability with varying bubble aspect ratio and for large-scale simulation of a 3-D random fluid interface. The numerical solution is compared with the experimental results by Taylor

Beryllium-10 in the Taylor Dome ice core: Applications to Antarctic glaciology and paleoclimatology

Energy Technology Data Exchange (ETDEWEB)

Steig, E.J.

1996-12-31

An ice core was drilled at Taylor dome, East Antarctica, reaching to bedrock at 554 meters. Oxygen-isotope measurements reveal climatic fluctuations through the last interglacial period. To facilitate comparison of the Taylor Dome paleoclimate record with geologic data and results from other deep ice cores, several glaciological issues need to be addressed. In particular, accumulation data are necessary as input for numerical ice-flow-models, for determining the flux of chemical constituents from measured concentrations, and for calculation of the offset in age between ice and trapped air in the core. The analysis of cosmogenic beryllium-10 provides a geochemical method for constraining the accumulation-rate history at Taylor Dome. High-resolution measurements were made in shallow firn cores and snow pits to determine the relationship among beryllium-10 concentrations, wet and dry deposition mechanisms, and snow-accumulation rates. Comparison between theoretical and measured variations in deposition over the last 75 years constrains the relationship between beryllium-10 deposition and global average production rates. The results indicate that variations in geomagnetically-modulated production-rate do not strongly influence beryllium-10 deposition at Taylor Dome. Although solar modulation of production rate is important for time scales of years to centuries, snow-accumulation rate is the dominant control on ice-core beryllium-10 concentrations for longer periods. Results show that the Taylor Dome core can be used to provide new constraints on regional climate over the last 130,000 years, complementing the terrestrial and marine geological record from the Dry Valley, Transantarctic Mountains and western Ross Sea.

Measuring Nominal and Real Convergence of Selected CEE Countries by the Taylor Rule

Directory of Open Access Journals (Sweden)

Böing Tobias

2016-12-01

Full Text Available We propose using a simple Taylor rule to evaluate business cycle convergence of the Czech Republic, Hungary, and Poland with the Eurozone. Our findings indicate an ongoing convergence of those CEE countries to the Eurozone, but with instabilities and heterogeneity between the countries. Especially Poland has shown a high degree of convergence in recent years. But there are still relevant differences in Taylor rates of each country to the Eurozone of about two percentage points.

Liquidity Traps with Global Taylor Rules

OpenAIRE

Stephanie Schmitt-Grohe; Martin Uribe

2000-01-01

A key result of a recent literature that focuses on the global consequences of Taylor-type interest rate feedback rules is that such rules, in combination with the zero-bound on nominal interest rates, can lead to unintended liquidity traps. An immediate question posed by this result is whether the government could avoid liquidity traps by ignoring the zero-bound, that is, by threatening to set the nominal interest rate at a negative value should the inflation rate fall below a certain thresh...

Heat transfer characteristics of liquid-gas Taylor flows incorporating microencapsulated phase change materials

International Nuclear Information System (INIS)

Howard, J A; Walsh, P A

2014-01-01

This paper presents an investigation on the heat transfer characteristics associated with liquid-gas Taylor flows in mini channels incorporating microencapsulated phase change materials (MPCM). Taylor flows have been shown to result in heat transfer enhancements due to the fluid recirculation experienced within liquid slugs which is attributable to the alternating liquid slug and gas bubble flow structure. Microencapsulated phase change materials (MPCM) also offer significant potential with increased thermal capacity due to the latent heat required to cause phase change. The primary aim of this work was to examine the overall heat transfer potential associated with combining these two novel liquid cooling technologies. By investigating the local heat transfer characteristics, the augmentation/degradation over single phase liquid cooling was quantified while examining the effects of dimensionless variables, including Reynolds number, liquid slug length and gas void fraction. An experimental test facility was developed which had a heated test section and allowed MPCM-air Taylor flows to be subjected to a constant heat flux boundary condition. Infrared thermography was used to record high resolution experimental wall temperature measurements and determine local heat transfer coefficients from the thermal entrance point. 30.2% mass particle concentration of the MPCM suspension fluid was examined as it provided the maximum latent heat for absorption. Results demonstrate a significant reduction in experimental wall temperatures associated with MPCM-air Taylor flows when compared with the Graetz solution for conventional single phase coolants. Total enhancement in the thermally developed region is observed to be a combination of the individual contributions due to recirculation within the liquid slugs and also absorption of latent heat. Overall, the study highlights the potential heat transfer enhancements that are attainable within heat exchange devices employing MPCM

The Bible and mission in faith perspective: J.Hudson Taylor and the early China Inland Mission

NARCIS (Netherlands)

Wigram, C.E.M.

2007-01-01

The thesis 'The Bible and Mission in Faith Perspective: J.Hudson Taylor and the Early China Inland Mission' by Christopher E.M. Wigram analysis the hermeneutical assumptions that underlay Hudson Taylor's approach to biblical interpretation, and the significance of his approach for the mission which

A crítica de Charles Taylor ao naturalismo na Ciência Política

Directory of Open Access Journals (Sweden)

Tiago Losso

2011-06-01

Full Text Available Os mais recentes esforços de revitalização do enfoque interpretativo na Ciência Política têm sua gênese na década de 1960, quando vários autores passaram a advogar a centralidade do estudo dos significados lingüístico e hermenêutico dos fenômenos políticos. Dentre tais autores, destaca-se o filósofo e politólogo Charles Taylor, cujos textos dos anos 1960 e 1970 desferem críticas contundentes ao naturalismo subjacente ao mainstream da Ciência Política da época. Meu objetivo é explorar a crítica de Taylor ao naturalismo, pensadas no contexto de uma proposta de abordagem interpretativa para a Ciência Política. Primeiramente, contextualizarei as contribuições de Taylor no âmbito mais amplo do interpretive turn nas Ciências Sociais. Em seguida, sumarizarei as reservas que Quentin Skinner e Clifford Geertz apresentam à crítica de Taylor.

Politics and naturalism in the 20th century psychology of Alfred Binet.

Science.gov (United States)

Foschi, Renato; Cicciola, Elisabetta

2006-11-01

Alfred Binet is internationally recognized as the "father" of the first intelligence test as well as the most faithful French representative of laboratory experimentalism. A historical analysis of his work is therefore necessary to get to a thorough comprehension of 20th century psychology. The present article, starting from Binet's intellectual path and from the suggestions of the previous historical literature, aims at providing fresh insights into Binet's work by trying to capture the intersections between Binet, his naturalistic culture and the political context in which he worked in the early 20th century, when he actively tried to apply experimental psychology to the pedagogical area. In fact, it is possible to underline, with reference to those years, an evident turn towards applications in Binet's psychological production. The article reconstructs the political and institutional background of Binet's research and shows how the naturalism and experimentalism he promoted were complementary to the solidarist conceptions that were particularly prevalent among those who supported his work during the Third Republic.

[Doctor and poet as rivals. Sigmund Freud, Alfred von Berger and the narrative of female homosexuality].

Science.gov (United States)

Goldmann, Stefan

2011-01-01

Starting from a passage in the Dora case history where Freud suggests some differences between a literary and a clinical narrative of female homosexuality, this paper presents examples which he might have had in mind. Besides Balzac's "La fille aux yeux d'or" (1834/35) it is in particular Alfred v. Berger's novella "Die Italienerin [The Italian woman]" (1904) which may have served as a model and counterpoint to the literary strategies used in Freud's case history. Freud had a relationship of long standing with Berger. This newly discovered source may provide a clue for the date at which Freud finalized the Dora manscript which he had held back for years.

Pediatric and adolescent applications of the Taylor Spatial Frame.

Science.gov (United States)

Paloski, Michael; Taylor, Benjamin C; Iobst, Christopher; Pugh, Kevin J

2012-06-01

Limb deformity can occur in the pediatric and adolescent populations from multiple etiologies: congenital, traumatic, posttraumatic sequelae, oncologic, and infection. Correcting these deformities is important for many reasons. Ilizarov popularized external fixation to accomplish this task. Taylor expanded on this by designing an external fixator in 1994 with 6 telescoping struts that can be sequentially manipulated to achieve multiaxial correction of deformity without the need for hinges or operative frame alterations. This frame can be used to correct deformities in children and has shown good anatomic correction with minimal morbidity. The nature of the construct and length of treatment affects psychosocial factors that the surgeon and family must be aware of prior to treatment. An understanding of applications of the Taylor Spatial Frame gives orthopedic surgeons an extra tool to correct simple and complex deformities in pediatric and adolescent patients. Copyright 2012, SLACK Incorporated.

Taylor-Made Education: The Influence of the Efficiency Movement on the Testing of Reading Skills.

Science.gov (United States)

Allen, JoBeth

Much of what has developed in the testing of reading harkens back to the days of the "Cult of Efficiency" movement in education that can be largely attributed to Frederick Winslow Taylor. Taylor spent most of his productive years studying time and motion in an attempt to streamline industrial production so that people could work as…

Rayleigh-Taylor instability in multi-structured spherical targets

International Nuclear Information System (INIS)

Gupta, N.K.; Lawande, S.V.

1986-01-01

An eigenvalue equation for the exponential growth rate of the Rayleigh-Taylor instability is derived in spherical geometry. The free surface and jump boundary conditions are obtained from the eigenvalue equation. The eigenvalue equation is solved in the cases where the initial fluid density profile has a step function or exponential variation in space and analytical formulae for growth rate of the instability are obtained. The solutions for the step function are generalized for any number N of spherical zones forming an arbitrary fluid density profile. The results of the numerical calculations for N spherical zones are compared with the exact analytical results for exponential fluid density profile with N=10 and a good agreement is observed. The formalism is further used to study the effects of density gradients on Rayleigh-Taylor instability in spherical geometry. Also analytical formulae are presented for a particular case of N=3 and shell targets. The formalism developed here can be used to study the growth of the instability in present day multi-structured shell targets. (author)

Nonlinear interaction of Rayleigh--Taylor and shear instabilities

International Nuclear Information System (INIS)

Finn, J.M.

1993-01-01

Results on the nonlinear behavior of the Rayleigh--Taylor instability and consequent development of shear flow by the shear instability [Phys. Fluids B 4, 488 (1992)] are presented. It is found that the shear flow is generated at sufficient amplitude to reduce greatly the convective transport. For high viscosity, the time-asymptotic state consists of an equilibrium with shear flow and vortex flow (with islands, or ''cat's eyes''), or a relaxation oscillation involving an interplay between the shear instability and the Rayleigh--Taylor instability in the presence of shear. For low viscosity, the dominant feature is a high-frequency nonlinear standing wave consisting of convective vortices localized near the top and bottom boundaries. The localization of these vortices is due to the smaller shear near the boundary regions. The convective transport is largest around these convective vortices near the boundary and there is a region of good confinement near the center. The possible relevance of this behavior to the H mode and edge-localized modes (ELM's) in the tokamak edge region is discussed

Taylor Dispersion Analysis as a promising tool for assessment of peptide-peptide interactions

DEFF Research Database (Denmark)

Høgstedt, Ulrich B; Schwach, Grégoire; van de Weert, Marco

2016-01-01

solutions increased with concentration. Our results indicate that a viscosity difference between run buffer and sample in Taylor Dispersion Analysis may result in overestimation of the measured diffusion coefficient. Thus, Taylor Dispersion Analysis provides a practical, but as yet primarily qualitative......Protein-protein and peptide-peptide (self-)interactions are of key importance in understanding the physiochemical behavior of proteins and peptides in solution. However, due to the small size of peptide molecules, characterization of these interactions is more challenging than for proteins...

Autenticitet og kritisk sprogfællesskab hos Charles Taylor

DEFF Research Database (Denmark)

Crone, Manni

2002-01-01

Lever vi i individualistiske samfund, hvor autenticitet og selvrealisering er blevet de højeste værdier? Den canadiske kommunitarist Charles Taylor argumenterer for, at selv om autenticitet og selvrealisering er vigtige værdier for det moderne menneske, kan en excessiv individualisme alligevel...

Surfactants and the Rayleigh-Taylor instability of Couette type flows

Science.gov (United States)

Frenkel, A. L.; Halpern, D.; Schweiger, A. S.

2011-11-01

We study the Rayleigh-Taylor instability of slow Couette- type flows in the presence of insoluble surfactants. It is known that with zero gravity, the surfactant makes the flow unstable to longwave disturbances in certain regions of the parameter space; while in other parametric regions, it reinforces the flow stability (Frenkel and Halpern 2002). Here, we show that in the latter parametric sectors, and when the (gravity) Bond number Bo is below a certain threshold value, the Rayleigh-Taylor instability is completely stabilized for a finite interval of Ma, the (surfactant) Marangoni number: MaL Ma2. For Ma Ma2, and also for MaL Ma2 as functions of the Bond number. We note that (for an interval of the Bond number) there are two distinct criticalities with nonzero (and distinct) critical wavenumbers.

Quantitative investigation of the transition process in Taylor-Couette flow

International Nuclear Information System (INIS)

Tu, Xin Cheng; Kim, Hyoung Bum Kim; Liu, Dong

2013-01-01

The transition process from circular Couette flow to Taylor vortex flow regime was experimentally investigated by measuring the instantaneous velocity vector fields at the annular gap flow region between two concentric cylinders. The proper orthogonal decomposition method, vorticity calculation, and frequency analysis were applied in order to analyze the instantaneous velocity fields to identify the flow characteristics during the transition process. From the results, the kinetic energy and corresponding reconstructed velocity fields were able to detect the onset of the transition process and the alternation of the flow structure. The intermittency and oscillation of the vortex flows during the transition process were also revealed from the analysis of the instantaneous velocity fields. The results can be a measure of identifying the critical Reynolds number of the Taylor-Couette flow from a velocity measurement method.

Clinical utility of the Taylor spatial frame for limb deformities

Directory of Open Access Journals (Sweden)

Keshet D

2017-05-01

Full Text Available Doron Keshet, Mark Eidelman Pediatric Orthopedics Unit, Rambam Health Care Center, Haifa, Israel Abstract: The Taylor spatial frame (TSF is a hexapod external fixator that can correct six-axis deformities. The mathematical base of all hexapod systems is projective geometry, which describes complex repositioning of an object in space. The Taylor brothers developed one of the first six-axis correction systems, which is known today as TSF. Over the years, this system has become the most used six-axis deformity correction device. In this review, we describe the history behind TSF development, and describe the principles and clinical utility for application of the TSF in different settings, such as acute trauma, malunions, and various deformities of the lower and upper limb. Keywords: external fixator, deformity correction, hexapod

Investigation of the Taylor vortices in electrovortex flow

Science.gov (United States)

Vinogradov, D. A.; Ivochkin, Yu P.; Teplyakov, I. O.

2017-10-01

The structure of the electrovortex flow appearing when the electric current passing through the liquid metal interacts with own and external magnetic fields was investigated numerically. It was shown that axial external magnetic field leads to the rotation of the liquid and generates secondary flow similar to Taylor vortex. Calculations were carried out for various ratios of electrode sizes.

Influence of a magnetic field on the Taylor instability in magnetic fluids

International Nuclear Information System (INIS)

Vislovich, A.N.

1986-01-01

The influence of a magnetic field on the stability of Couette flow between rotating cylinders is investigated in the narrow gap approximation. The governing mechanism of the instability is the classical Taylor mechanism. It was shown that rotation of the outer cylinder in the same direction as the inner does not result in a qualitative change in the structure of the theshold perturbations. When the cylinders rotate in different directions in an ordinary fluid, the Taylor vortices develop in the domain of the gap between the inner cylinder and the fluid layer for which v 0 = 0

LASNEX simulations of the classical and laser-driven Rayleigh-Taylor instability

International Nuclear Information System (INIS)

Mikaelian, K.O.

1990-01-01

We present the results of two-dimensional LASNEX simulations of the classical and laser-driven Rayleigh-Taylor instability. Our growth rates and eigenmodes for classical two- and three-fluid problems agree closely with the exact analytic expressions. We illustrate in several examples how perturbations feed through from one interface to another. For targets driven by a 1/4-μm laser at I=2x10 14 W/cm 2 our growth rates are 40--80 % of the classical case rates for wavelengths between 5 and 100 μm. We find that radiation transport has a stabilizing effect on the Rayleigh-Taylor instability, particularly at high intensities. A brief comparison with a laser-driven experiment is also presented

Theoretical and numerical study of Rayleigh-Taylor instabilities in magnetized plasmas; Etude theorique et numerique des instabilites rayleigh-taylor en plasmas magnetises

Energy Technology Data Exchange (ETDEWEB)

Andrei, A. Ivanov

2001-06-15

In this thesis we're studying both the general case of the 'classic' Rayleigh-Taylor instability (in incompressible fluids) and more specific cases of the instabilities of Rayleigh-Taylor type in magnetized plasmas, in the liners or wire array implosions etc. We have studied the influence of the Hall diffusion of magnetic field on the growth rate of the instability. We have obtained in this work a self-similar solution for the widening of the initial profile of the magnetic field and for the wave of the penetration of magnetic field. After that the subsequent evolution of the magnetic field in plasma opening switches (POS) has been examined. We have shown the possibility of the existence of a strong rarefaction wave for collisional and non-collisional cases. This wave can explain the phenomenon of the opening of POS. The effect of the suppression of Rayleigh-Taylor instability by forced oscillations of the boundary between two fluids permits us to propose some ideas for the experiments of inertial fusion. We have considered the general case of the instability, in other words - two incompressible viscous superposed fluids in a gravitational field. We have obtained an exact analytical expression for the growth rate and then we have analyzed the influence of the parameters of external 'pumping' on the instability. These results can be applied to a wide range of systems, starting from classic hydrodynamics and up to astrophysical plasmas. The scheme of wire arrays has become recently a very popular method to obtain a high power X-radiation or for a high quality implosion in Z-pinches. The experimental studies have demonstrated that the results of implosion are much better for the case of multiple thin wires situated cylindrically than in a usual liner scheme. We have examined the problem modeling the stabilization of Rayleigh-Taylor instability for a wire array system. The reason for instability suppression is the regular spatial modulation of

Saffman-Taylor fingers with kinetic undercooling

KAUST Repository

Gardiner, Bennett P. J.

2015-02-23

© 2015 American Physical Society. The mathematical model of a steadily propagating Saffman-Taylor finger in a Hele-Shaw channel has applications to two-dimensional interacting streamer discharges which are aligned in a periodic array. In the streamer context, the relevant regularization on the interface is not provided by surface tension but instead has been postulated to involve a mechanism equivalent to kinetic undercooling, which acts to penalize high velocities and prevent blow-up of the unregularized solution. Previous asymptotic results for the Hele-Shaw finger problem with kinetic undercooling suggest that for a given value of the kinetic undercooling parameter, there is a discrete set of possible finger shapes, each analytic at the nose and occupying a different fraction of the channel width. In the limit in which the kinetic undercooling parameter vanishes, the fraction for each family approaches 1/2, suggesting that this "selection" of 1/2 by kinetic undercooling is qualitatively similar to the well-known analog with surface tension. We treat the numerical problem of computing these Saffman-Taylor fingers with kinetic undercooling, which turns out to be more subtle than the analog with surface tension, since kinetic undercooling permits finger shapes which are corner-free but not analytic. We provide numerical evidence for the selection mechanism by setting up a problem with both kinetic undercooling and surface tension and numerically taking the limit that the surface tension vanishes.

Saffman-Taylor fingers with kinetic undercooling

KAUST Repository

Gardiner, Bennett P. J.; McCue, Scott W.; Dallaston, Michael C.; Moroney, Timothy J.

2015-01-01

© 2015 American Physical Society. The mathematical model of a steadily propagating Saffman-Taylor finger in a Hele-Shaw channel has applications to two-dimensional interacting streamer discharges which are aligned in a periodic array. In the streamer context, the relevant regularization on the interface is not provided by surface tension but instead has been postulated to involve a mechanism equivalent to kinetic undercooling, which acts to penalize high velocities and prevent blow-up of the unregularized solution. Previous asymptotic results for the Hele-Shaw finger problem with kinetic undercooling suggest that for a given value of the kinetic undercooling parameter, there is a discrete set of possible finger shapes, each analytic at the nose and occupying a different fraction of the channel width. In the limit in which the kinetic undercooling parameter vanishes, the fraction for each family approaches 1/2, suggesting that this "selection" of 1/2 by kinetic undercooling is qualitatively similar to the well-known analog with surface tension. We treat the numerical problem of computing these Saffman-Taylor fingers with kinetic undercooling, which turns out to be more subtle than the analog with surface tension, since kinetic undercooling permits finger shapes which are corner-free but not analytic. We provide numerical evidence for the selection mechanism by setting up a problem with both kinetic undercooling and surface tension and numerically taking the limit that the surface tension vanishes.

Monetary Policy and the Taylor Principle in Open Economies

NARCIS (Netherlands)

Linnemann, L.; Schabert, A.

2006-01-01

Nowadays, central banks mostly conduct monetary policy by setting nominal interest rates. A widely held view is that central banks can stabilize inflation if they follow the Taylor principle, which requires raising the nominal interest rate more than one-for-one in response to higher inflation. Is

Coherent structures in ablatively compressed ICF targets and Rayleigh-Taylor instability

International Nuclear Information System (INIS)

Pant, H.C.; Desai, T.

1996-01-01

One of the major issues in laser induced inertial confinement fusion (ICF) is a stable ablative compression of spherical fusion pellets. The main impediment in achievement of this objective is Rayleigh-Taylor instability at the pellet's ablation front. Under sufficiently high acceleration this instability can grow out of noise. However, it can also arise either due to non-uniform laser intensity distribution over the pellet surface or due to pellet wall areal mass irregularity. Coherent structures in the dense target behind the ablation front can be effectively utilised for stabilisation of the Rayleigh-Taylor phenomenon. Such coherent structures in the form of a super lattice can be created by doping the pellet pusher with high atomic number (Z) micro particles. A compressed-cool pusher under laser irradiation behaves like a strongly correlated non ideal plasma when compressed to sufficiently high density such that the non ideality parameter exceeds unity. Moreover, the nonideality parameter for high Z microinclusions may exceed a critical value of 180 and as a consequence they remain in the form of intact clusters, maintaining the superlattice intact during ablative acceleration. Micro-hetrogeneity and its superlattice plays an important role in stabilization of Rayleigh-Taylor instability, through a variety of mechanisms. (orig.)

La ética de la autoconservación y la teoría de los deberes políticos en el Leviatán de Hobbes*

OpenAIRE

Francisco Cortéz Rodas

2002-01-01

“The Ethics of Self-Preservation and the Theory of Political Duties in Hobbes’ Leviathan”. In order to present the political argument in Thomas Hobbes’ Leviathan, the author proposes an interpretation of his doctrine developed by Alfred Taylor, Howard Warrender and Michael Oakeshott. According to this interpretation, Hobbesian ethics, as developed in his theory of the laws of nature, once distinguished from his selfish psychology, shows itself as a strict deontological ethics, very close to K...

Stochastic model of Rayleigh-Taylor turbulent mixing

International Nuclear Information System (INIS)

Abarzhi, S.I.; Cadjan, M.; Fedotov, S.

2007-01-01

We propose a stochastic model to describe the random character of the dissipation process in Rayleigh-Taylor turbulent mixing. The parameter alpha, used conventionally to characterize the mixing growth-rate, is not a universal constant and is very sensitive to the statistical properties of the dissipation. The ratio between the rates of momentum loss and momentum gain is the statistic invariant and a robust parameter to diagnose with or without turbulent diffusion accounted for

A taylor series approach to survival analysis

International Nuclear Information System (INIS)

Brodsky, J.B.; Groer, P.G.

1984-09-01

A method of survival analysis using hazard functions is developed. The method uses the well known mathematical theory for Taylor Series. Hypothesis tests of the adequacy of many statistical models, including proportional hazards and linear and/or quadratic dose responses, are obtained. A partial analysis of leukemia mortality in the Life Span Study cohort is used as an example. Furthermore, a relatively robust estimation procedure for the proportional hazards model is proposed. (author)

Taylor Law in Wind Energy Data

Directory of Open Access Journals (Sweden)

Rudy Calif

2015-10-01

Full Text Available The Taylor power law (or temporal fluctuation scaling, is a scaling relationship of the form σ ~  (Pλ where !! is the standard deviation and hPi the mean value of a sample of a time series has been observed for power output data sampled at 5 min and 1 s and from five wind farms and a single wind turbine, located at different places. Furthermore, an analogy with the turbulence field is performed, consequently allowing the establishment of a scaling relationship between the turbulent production IP and the mean value (P.

Validity of the Taylor hypothesis for linear kinetic waves in the weakly collisional solar wind

International Nuclear Information System (INIS)

Howes, G. G.; Klein, K. G.; TenBarge, J. M.

2014-01-01

The interpretation of single-point spacecraft measurements of solar wind turbulence is complicated by the fact that the measurements are made in a frame of reference in relative motion with respect to the turbulent plasma. The Taylor hypothesis—that temporal fluctuations measured by a stationary probe in a rapidly flowing fluid are dominated by the advection of spatial structures in the fluid rest frame—is often assumed to simplify the analysis. But measurements of turbulence in upcoming missions, such as Solar Probe Plus, threaten to violate the Taylor hypothesis, either due to slow flow of the plasma with respect to the spacecraft or to the dispersive nature of the plasma fluctuations at small scales. Assuming that the frequency of the turbulent fluctuations is characterized by the frequency of the linear waves supported by the plasma, we evaluate the validity of the Taylor hypothesis for the linear kinetic wave modes in the weakly collisional solar wind. The analysis predicts that a dissipation range of solar wind turbulence supported by whistler waves is likely to violate the Taylor hypothesis, while one supported by kinetic Alfvén waves is not.

Traveling waves in a magnetized Taylor-Couette flow

International Nuclear Information System (INIS)

Liu Wei; Ji Hantao; Goodman, Jeremy

2007-01-01

We investigate numerically a traveling wave pattern observed in experimental magnetized Taylor-Couette flow at low magnetic Reynolds number. By accurately modeling viscous and magnetic boundaries in all directions, we reproduce the experimentally measured wave patterns and their amplitudes. Contrary to previous claims, the waves are shown to be transiently amplified disturbances launched by viscous boundary layers, rather than globally unstable magnetorotational modes

Theoretical and numerical studies of Rayleigh-Taylor instabilities in magnetized plasmas

International Nuclear Information System (INIS)

Ivanov, A.A.

2001-06-01

The instabilities of Rayleigh-Taylor type are considered in the thesis. The topic of the thesis was inspired by recent advances in the physics of plasma compression, especially with the aid of systems like Z-pinch. Rayleigh-Taylor instability (RTI) plays an important role in the evolution of magnetized plasmas in these experiments, as well as in stellar plasmas and classic fluids. For the phenomena concerning the nuclear fusion the RTI is very often the factor limiting the possibility of compression. In the current work we try to examine in detail the characteristic features of the instabilities of this type in order to eliminate their detrimental influence. In this thesis we are studying both the general case of the 'classic' Rayleigh-Taylor instability (in incompressible fluids) and more specific cases of the instabilities of Rayleigh-Taylor type in magnetized plasmas, in the liners or wire array implosions etc. We have studied the influence of the Hall diffusion of magnetic field on the growth rate of the instability. We have obtained in this work a self-similar solution for the widening of the initial profile of the magnetic field and for the wave of the penetration of magnetic field. After that the subsequent evolution of the magnetic field in plasma opening switches (POS) has been examined. We have shown the possibility of the existence of a strong rarefaction wave for collisional and non-collisional cases. This wave can explain the phenomenon of the opening of POS. The effect of the suppression of Rayleigh-Taylor instability by forced oscillations of the boundary between two fluids permits us to propose some ideas for the experiments of inertial fusion. We have considered the general case of the instability, in other words, two incompressible viscous superposed fluids in a gravitational field. We have obtained an exact analytical expression for the growth rate and then we have analyzed the influence of the parameters of external 'pumping' on the instability

[Alfred Kohn, professor of histology at German University in Prague].

Science.gov (United States)

Nanka, O; Grim, M

2008-01-01

Prof. Kohn (1867-1959) was the head of the Institute of Histology at the Medical Faculty of German University in Prague for 26 years. In 2007 we commemorated his 140th birthday, and 2009 we will remember the 50th anniversary of his death. He entered the history of medicine by discovery of nature and origin of parathyroid glands and by pioneer research into chromaffin cells and sympathetic paraganglia. Kohn's papers on the pituitary, interstitial cells of testes, and ovaries are also related to endocrinology. All his studies are based on descriptive and comparative histological and embryological observations. Kohn was twice the dean of German Medical Faculty, and a member or honorary member of many important scientific societies. He was repeatedly nominated for Nobel Prize for physiology and medicine. For his Jewish origin he was expelled from Deutsche Gesellschaft der Wissenschaften und Künste für die Tschechoslowakische Republik in 1939 and transported to Terezin ghetto in 1943. After the war he lived in Prague. On the occasion of his 90th birthday he was elected honorary president of Anatomische Gesellschaft and awarded by the Czechoslovak Order of Labour. Alfred Kohn died in 1959. He was one of the outstanding personalities that Prague gave to the world of science.

Development of Rayleigh-Taylor and bulk convection instabilities in the dynamics of plasma liners and pinches

International Nuclear Information System (INIS)

Bud'ko, A.B.; Velikovich, A.L.; Liberman, M.A.; Felber, F.S.

1989-01-01

A solution is derived for the problem of the initial, linear stage of the growth of small perturbations in the course of the cylindrically symmetric compression and expansion of a plasma liner and a Z-pinch with a sharp boundary. In these systems, Rayleigh-Taylor instabilities localized near the plasma boundaries are the most dangerous. Bulk convective instabilities develop in addition to these Rayleigh-Taylor instabilities. The various instability modes, including local and global Rayleigh-Taylor modes, which grown in an accelerated plasma with distributed profiles of hydrodynamic variables, are classified. The spectra of the instability growth rates are calculated for plasma liners and Z-pinches. The shape of these spectra reveals an explanation of the stratification and filamentation of the plasma observed experimentally in pinches and liners. The imposition of a longitudinal magnetic field gives rise to a stability window in the space of the flow parameters. In this window, the Rayleigh-Taylor modes are suppressed completely by magnetic shear, while the bulk convective modes are suppressed to a significant extent

Effect of magnetic field on Rayleigh-Taylor instability of quantum and stratified plasma in porous medium

International Nuclear Information System (INIS)

Sharma, P.K.; Tiwari, Anita; Argal, Shraddha; Chhajlani, R.K.

2013-01-01

This paper is devoted to an investigation of Quantum effects and magnetic field effects on the Rayleigh Taylor instability of two superposed incompressible fluids in bounded porous medium. The Quantum magneto hydrodynamic equations are solved by using normal mode method and a dispersion relation is obtained. The dispersion relation is derived for the case where plasma is bounded by two rigid planes z = 0 and z = h. The Rayleigh Taylor instability growth rate and stability condition of the medium is discussed in the presence of quantum effect, magnetic field, porosity and permeability. It is found that the magnetic field and medium porosity have stabilizing influence while permeability has destabilizing influence on the Rayleigh Taylor instability. (author)

A Brief Discussion on the Outlook on Life and Death——A Comparative Analysis of Emily Dickinson and Alfred Tennyson

Institute of Scientific and Technical Information of China (English)

龚玉龙; 张华园

2015-01-01

Since ancient times,large numbers of poets throughout the world have elaborated their outlook on life and death through their works.Among them are Emily Dickinson and Alfred Tennyson,the outstanding poetess and poet in the 19th century,who have a unique and thorough meditation on life and death.From the comparative analysis of their view on life and death we could extract a good deal of spiritual treasure to provide a scientific guidance for people in modern society.

From Taylor to Drucker: Management and Managing

OpenAIRE

Primoz Turk

2008-01-01

The article discusses the question of management and managing, focusing on the changes which took place in the period from Taylor to Drucker. In this period two turning points dramatically changed the nature of management. Management which started within the organization was at first concerned with the organization’s inner workings. This concern with the organization’s ‘inside’ is gradually projected to the outside, to society as a whole. Simultaneously, changes occur in managing. Managing wh...

Liquidity Trap and Stability of Taylor Rules

OpenAIRE

Le Riche , Antoine; Magris , Francesco; Parent , Antoine

2016-01-01

We study a productive economy with fractional cash-in-advance constraint on consumption expenditures. Government issues safe bonds and levies taxes to finance public expenditures, while the Central Bank follows a feedback Taylor rules by pegging the nominal interest rate. We show that when the nominal interest rate is bound to be non-negative, under active policy rules a Liquidity Trap steady state does emerge besides the Leeper (1991) equilibrium. The stability of the two steady states depen...

Direct numerical simulations of type Ia supernovae flames II: The Rayleigh-Taylor instability

International Nuclear Information System (INIS)

Bell, J.B.; Day, M.S.; Rendleman, C.A.; Woosley, S.E.; Zingale, M.

2004-01-01

A Type Ia supernova explosion likely begins as a nuclear runaway near the center of a carbon-oxygen white dwarf. The outward propagating flame is unstable to the Landau-Darrieus, Rayleigh-Taylor, and Kelvin-Helmholtz instabilities, which serve to accelerate it to a large fraction of the speed of sound. We investigate the Rayleigh-Taylor unstable flame at the transition from the flamelet regime to the distributed-burning regime, around densities of 10e7 gm/cc, through detailed, fully resolved simulations. A low Mach number, adaptive mesh hydrodynamics code is used to achieve the necessary resolution and long time scales. As the density is varied, we see a fundamental change in the character of the burning--at the low end of the density range the Rayleigh-Taylor instability dominates the burning, whereas at the high end the burning suppresses the instability. In all cases, significant acceleration of the flame is observed, limited only by the size of the domain we are able to study. We discuss the implications of these results on the potential for a deflagration to detonation transition

Measurement of the Rayleigh-Taylor instability in targets driven by optically smoothed laser beams

International Nuclear Information System (INIS)

Desselberger, M.; Willi, O.; Savage, M.; Lamb, M.J.

1990-01-01

Growth rates of the Rayleigh-Taylor instability were measured in targets with imposed sinusoidal modulations irradiated by optically smoothed 0.53-μm laser beams. A hybrid optical smoothing technique utilizing induced-spatial-incoherence and random-phase-plate technology was used for the first time. The wave-number dependence and the nonlinear behavior of Rayleigh-Taylor growth were investigated by using targets with a range of modulation periodicities and depths. The results are compared to 2D hydrodynamic-code simulations

James Alfred Loader: ’n Huldeblyk aan ’n krities-solidêre profeet in die eties-teologiese tradisie/James Alfred Loader: A tribute to a critical-solidary prophet in the ethical theological tradition

Directory of Open Access Journals (Sweden)

Andries G. van Aarde

2013-11-01

Full Text Available This article is the introduction to the James Alfred Loader Dedication. It consists of a tribute to Professor Loader’s academic contribution to Old Testament, Middle-Eastern religio-literary studies and the Rabbinical background of the Old- and New Testament. The article is modelled after the tribute published in German in the annual publication of the Evangelisch-Theologische Fakultät Wien (Vienna, Austria due to the honorary doctorate conferred on Professor Loader by the University of Pretoria (South Africa in 2009. The tribute is combined with a comprehensive curriculum vitae, in part written in German, Afrikaans and English, and consisting of referencing Professor Loader’s personal data, his role as minister of religion, his academic awards, participation in scholarly societies, professional academic positions, academic reviewing, editorial activity, presentation of academic papers and a list of publications.

A riposte for a fencer. The residency appointment of Alfred Edmund Finckh to Sydney Hospital in 1905. Was it just a matter of male chauvinism?

Science.gov (United States)

Finckh, E S; Finckh, A S

Alfred Finckh gained a residency at Sydney Hospital in 1905 in preference to a more academically successful female medical graduate, amid some controversy over the place of female doctors in hospitals. Here, two of his descendants argue his cause: that he was an experienced scientist with qualities that merited his selection for the post.

The carbon stable isotope biogeochemistry of streams, Taylor Valley, Antarctica

International Nuclear Information System (INIS)

Lyons, W.B.; Leslie, D.L.; Harmon, R.S.; Neumann, K.; Welch, K.A.; Bisson, K.M.; McKnight, D.M.

2013-01-01

Highlights: ► δ 13 C-DIC reported from McMurdo Dry Valleys, Antarctica, streams. ► Stream water δ 13 C PDB values range −9.4‰ to +5.1‰, largely inorganic in character. ► Atmospheric exchange is the dominant control on δ 13 C-DIC. - Abstract: The McMurdo Dry Valleys region of Antarctica is the largest ice-free region on the continent. This study reports the first C stable isotope measurements for dissolved inorganic C present in ephemeral streams in four dry valleys that flow for four to twelve weeks during the austral summer. One of these valleys, Taylor Valley, has been the focus of the McMurdo Dry Valleys Long-Term Ecological Research (MCM-LTER) program since 1993. Within Taylor Valley, numerous ephemeral streams deliver water to three perennially ice-covered, closed-basin lakes: Lake Fryxell, Lake Hoare, and Lake Bonney. The Onyx River in the Wright Valley, the longest river in Antarctica, flows for 40 km from the Wright Lower Glacier and Lake Brownworth at the foot of the glacier to Lake Vanda. Streamflow in the McMurdo Dry Valley streams is produced primarily from glacial melt, as there is no overland flow. However, hyporheic zone exchange can be a major hydrogeochemical process in these streams. Depending on landscape position, these streams vary in gradient, channel substrate, biomass abundance, and hyporheic zone extent. This study sampled streams from Taylor, Wright, Garwood, and Miers Valleys and conducted diurnal sampling of two streams of different character in Taylor Valley. In addition, transect sampling was undertaken of the Onyx River in Wright Valley. The δ 13 C PDB values from these streams span a range of greater than 14‰, from −9.4‰ to +5.1‰, with the majority of samples falling between −3‰ and +2‰, suggesting that the C stable isotope composition of dissolved C in McMurdo Dry Valley streams is largely inorganic in character. Because there are no vascular plants on this landscape and no groundwater input to these

Parametric modulation in the Taylor-Couette ferrofluid flow

International Nuclear Information System (INIS)

Singh, Jitender; Bajaj, Renu

2008-01-01

A parametric instability of the Taylor-Couette ferrofluid flow excited by a periodically oscillating magnetic field, has been investigated numerically. The Floquet analysis has been employed. It has been found that the modulation of the applied magnetic field affects the stability of the basic flow. The instability response has been found to be synchronous with respect to the frequency of periodically oscillating magnetic field.

Rayleigh-Taylor instability in an equal mass plasma

Energy Technology Data Exchange (ETDEWEB)

Adak, Ashish, E-mail: ashish-adak@yahoo.com [Department of Instrumentation Science, Jadavpur University, Kolkata 700 032 (India); Ghosh, Samiran, E-mail: sran-g@yahoo.com [Department of Applied Mathematics, University of Calcutta 92, Acharya Prafulla Chandra Road, Kolkata 700 009 (India); Chakrabarti, Nikhil, E-mail: nikhil.chakrabarti@saha.ac.in [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064 (India)

2014-09-15

The Rayleigh-Taylor (RT) instability in an inhomogeneous pair-ion plasma has been analyzed. Considering two fluid model for two species of ions (positive and negative), we obtain the possibility of the existence of RT instability. The growth rate of the RT instability as usual depends on gravity and density gradient scale length. The results are discussed in context of pair-ion plasma experiments.

Alfred Russel Wallace's medical libertarianism: state medicine, human progress, and evolutionary purpose.

Science.gov (United States)

Flannery, Michael A

2015-01-01

Alfred Russel Wallace (1823-1913), naturalist and explorer of South America and the Malay Archipelago, secured his place in history by independently discovering the theory of natural selection. His letter outlining the theory was sent from Ternate in eastern Indonesia and received at Down House, according to Charles Darwin (1809-82), on June 18, 1858, prompting the now-famed evolutionist to rush his languishing manuscript to press. Wallace's contributions to evolutionary biology, biogeography, and anthropology are well known, but his medical views have received far less attention. Within the context of a strident populist antivaccination movement and an ominous elitist eugenics campaign, Wallace took his stand, which revealed itself in a libertarianism that defended traditional socialist constituencies (the working poor, the lumpenproletariat, and feminist reformers) against state-mandated medical interventions. Rather than viewing Wallace as a heterodox contrarian, this article argues that his positions were logical outgrowths of his medical libertarianism and evolutionary and social theories. © The Author 2013. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Taylor-expansion Monte Carlo simulations of classical fluids in the canonical and grand canonical ensemble

International Nuclear Information System (INIS)

Schoen, M.

1995-01-01

In this article the Taylor-expansion method is introduced by which Monte Carlo (MC) simulations in the canonical ensemble can be speeded up significantly, Substantial gains in computational speed of 20-40% over conventional implementations of the MC technique are obtained over a wide range of densities in homogeneous bulk phases. The basic philosophy behind the Taylor-expansion method is a division of the neighborhood of each atom (or molecule) into three different spatial zones. Interactions between atoms belonging to each zone are treated at different levels of computational sophistication. For example, only interactions between atoms belonging to the primary zone immediately surrounding an atom are treated explicitly before and after displacement. The change in the configurational energy contribution from secondary-zone interactions is obtained from the first-order term of a Taylor expansion of the configurational energy in terms of the displacement vector d. Interactions with atoms in the tertiary zone adjacent to the secondary zone are neglected throughout. The Taylor-expansion method is not restricted to the canonical ensemble but may be employed to enhance computational efficiency of MC simulations in other ensembles as well. This is demonstrated for grand canonical ensemble MC simulations of an inhomogeneous fluid which can be performed essentially on a modern personal computer

CBR Operations in Cold Weather: A Bibliography. Volume 1

Science.gov (United States)

1989-11-01

JOHNSTON R C SWAMP OAK TEST DATA DOD/DROLS ; HANNEMANN M M D ANALYSIS. 514727L ;HALLANGER N L ;KROTH J R ;WESTLAKE WILFRED J ; HAMILTON WILLIAM M 1953...E 1963 HANNA ALFRED E; SIMULATED COLD WEATHER DOD/DROLS RADIOLOGICAL DECONTAMINATION 296248 OF RECOVERY EQUIPMENT. HANNEMANN M M D 1967 JOHNSTON R C...SWAMP OAK TEST DATA DOD/DROLS ; HANNEMANN M M D ANALYSIS. 514727L ;HALLANGER N L ;KROTH J R ;WESTLAKE WILFRED J : 37 HELLBERG E N 1961 TAYLOR D

Inward propagating chemical waves in Taylor vortices.

Science.gov (United States)

Thompson, Barnaby W; Novak, Jan; Wilson, Mark C T; Britton, Melanie M; Taylor, Annette F

2010-04-01

Advection-reaction-diffusion (ARD) waves in the Belousov-Zhabotinsky reaction in steady Taylor-Couette vortices have been visualized using magnetic-resonance imaging and simulated using an adapted Oregonator model. We show how propagating wave behavior depends on the ratio of advective, chemical and diffusive time scales. In simulations, inward propagating spiral flamelets are observed at high Damköhler number (Da). At low Da, the reaction distributes itself over several vortices and then propagates inwards as contracting ring pulses--also observed experimentally.

Taylor Principle Supplements the Fisher Effect: Empirical Investigation under the US Context

Directory of Open Access Journals (Sweden)

Mohammed Saiful ISLAM

2012-06-01

Full Text Available This paper reviews the short- and long-run dynamics of interest rate and inflation of the United States. Basing upon quarterly as well as monthly data over the period 1957 to 2010, we find evidence that interest rate behaviour of the Federal Reserve is consistent with the Taylor principle in short run and with the Fisher hypothesis in long run. Entire sample justifies the existence of a long run cointegrating relationship between federal funds rate and inflation characterised as the Fisher effect. When data are split into different subsamples, the cointegrating relationship disappears. Interest rate dynamics of pre-1980 and post-2001 neither track Fisher hypothesis nor Taylor principle, rather represent substantial discretion.

Daring to disturb the universe: Heidegger’s authenticity and The love song of J. Alfred Prufrock

Directory of Open Access Journals (Sweden)

D. Griffiths

2009-07-01

Full Text Available In Heidegger’s “Being and time” certain concepts are discussed which are central to the ontological constitution of “Dasein”. This article demonstrates the interesting way in which some of these concepts can be used in a reading of T.S. Eliot’s “The love song of J. Alfred Prufrock”. A comparative analysis is performed, explicating the relevant Heideggerian terms and then relating them to Eliot’s poem. In this way strong parallels are revealed between the two men’s respective thoughts and distinct modernist sensibilities. Prufrock, the protagonist of the poem, and the world he inhabits illustrate poetically concepts such as authenticity, inauthenticity, the “they”, idle talk and angst, which Heidegger develops in “Being and time”.

Identità e riconoscimento in Charles Taylor

Directory of Open Access Journals (Sweden)

Francesca Caputo

2013-06-01

Full Text Available The model of the politic of difference, proposed by Charles Taylor, in the wake of a conception of liberalism ‘hospitable’, unfolds in a journey aimed to comply with the ontological dimensions of the dignity of different cultures, of cultural traditions and ways of life. Being a self, constructed in terms of dialogue and dialectic of mutual recognition between cultures, refers, in the Charles Taylor’s reflection, to the safeguarding of single, intersubjective or common meanings of specific social, moral, narrative spaces.

Hydromagnetic Rayleigh-Taylor instability in cylindrical implosions

International Nuclear Information System (INIS)

Hwang, C.S.; Roderick, N.F.; Wu, M.W.

1986-01-01

Rayleigh-Taylor Instability in the (r,Θ) plane has been solved by the variational approach. Results are compared to the analytical solutions of two-region and three-region problems at the infinite radius. They show the magnetic stabilization effect. Growth rates in this plane are decreased by the effects of plasma shell thickness, plasma shell radius, magnetic tension, magnetic diffusion and finite density gradient of the plasma magnetic field interface. The most unstable mode number decreases when the radius of the plasma shell decreases

The solution of the point kinetics equations via converged accelerated Taylor series (CATS)

Energy Technology Data Exchange (ETDEWEB)

Ganapol, B.; Picca, P. [Dept. of Aerospace and Mechanical Engineering, Univ. of Arizona (United States); Previti, A.; Mostacci, D. [Laboratorio di Montecuccolino, Alma Mater Studiorum - Universita di Bologna (Italy)

2012-07-01

This paper deals with finding accurate solutions of the point kinetics equations including non-linear feedback, in a fast, efficient and straightforward way. A truncated Taylor series is coupled to continuous analytical continuation to provide the recurrence relations to solve the ordinary differential equations of point kinetics. Non-linear (Wynn-epsilon) and linear (Romberg) convergence accelerations are employed to provide highly accurate results for the evaluation of Taylor series expansions and extrapolated values of neutron and precursor densities at desired edits. The proposed Converged Accelerated Taylor Series, or CATS, algorithm automatically performs successive mesh refinements until the desired accuracy is obtained, making use of the intermediate results for converged initial values at each interval. Numerical performance is evaluated using case studies available from the literature. Nearly perfect agreement is found with the literature results generally considered most accurate. Benchmark quality results are reported for several cases of interest including step, ramp, zigzag and sinusoidal prescribed insertions and insertions with adiabatic Doppler feedback. A larger than usual (9) number of digits is included to encourage honest benchmarking. The benchmark is then applied to the enhanced piecewise constant algorithm (EPCA) currently being developed by the second author. (authors)

Pinch instabilities in Taylor-Couette flow.

Science.gov (United States)

Shalybkov, Dima

2006-01-01

The linear stability of the dissipative Taylor-Couette flow with an azimuthal magnetic field is considered. Unlike ideal flows, the magnetic field is a fixed function of a radius with two parameters only: a ratio of inner to outer cylinder radii, eta, and a ratio of the magnetic field values on outer and inner cylinders, muB. The magnetic field with 0rotation. The unstable modes are located into some interval of the axial wave numbers for the flow stable without magnetic field. The interval length is zero for a critical Hartmann number and increases with an increasing Hartmann number. The critical Hartmann numbers and length of the unstable axial wave number intervals are the same for every rotation law. There are the critical Hartmann numbers for m=0 sausage and m=1 kink modes only. The sausage mode is the most unstable mode close to Ha=0 point and the kink mode is the most unstable mode close to the critical Hartmann number. The transition from the sausage instability to the kink instability depends on the Prandtl number Pm and this happens close to one-half of the critical Hartmann number for Pm=1 and close to the critical Hartmann number for Pm=10(-5). The critical Hartmann numbers are smaller for kink modes. The flow stability does not depend on magnetic Prandtl numbers for m=0 mode. The same is true for critical Hartmann numbers for both m=0 and m=1 modes. The typical value of the magnetic field destabilizing the liquid metal Taylor-Couette flow is approximately 10(2) G.

De la ilegibilidad de lo ajeno. lectura mágica y escritura mimética en Alfred Döblin

Directory of Open Access Journals (Sweden)

Sven Werkmeister

2012-12-01

Full Text Available The article discusses and questions the concept of "cultural text" developed by anthropologists such as Clifford Geertz. The theory of culture as text opens the possibility of a semiotic reading of the cultural text, giving the anthropologist the role of hermeneutic interpreter of foreign cultures as systems of symbols. The paper shows, through analysis the literary of trilogy Amazons from German writer Alfred Dóblin, that the ethnographic approach is not always characterized by processes of understanding and interpretation, but is just the reflection of illegibility phenomena can be a fruitful basis for a cultural approach.

Life stages of wall-bounded decay of Taylor-Couette turbulence

NARCIS (Netherlands)

Ostilla-Mónico, Rodolfo; Zhu, Xiaojue; Arza, Vamsi Spandan; Verzicco, Roberto; Lohse, Detlef

2017-01-01

The decay of Taylor-Couette turbulence, i.e., the flow between two coaxial and independently rotating cylinders, is numerically studied by instantaneously stopping the forcing from an initially statistically stationary flow field at a Reynolds number of Re=3.5×104. The effect of wall friction is

Evidence for mate guarding behavior in the Taylor's checkerspot butterfly

Science.gov (United States)

Victoria J. Bennett; Winston P. Smith; Matthew G. Betts

2011-01-01

Discerning the intricacies of mating systems in butterflies can be difficult, particularly when multiple mating strategies are employed and are cryptic and not exclusive. We observed the behavior and habitat use of 113 male Taylor's checkerspot butterflies (Euphydryas editha taylori). We confirmed that two distinct mating strategies were...

Horizontally viscous effects in a tidal basin: extending Taylor's problem

NARCIS (Netherlands)

Roos, Pieter C.; Schuttelaars, H.M.

2009-01-01

The classical problem of Taylor (Proc. Lond. Math. Soc., vol. 20, 1921, pp. 148–181) of Kelvin wave reflection in a semi-enclosed rectangular basin of uniform depth is extended to account for horizontally viscous effects. To this end, we add horizontally viscous terms to the hydrodynamic model

The verification of the Taylor-expansion moment method in solving aerosol breakage

Directory of Open Access Journals (Sweden)

Yu Ming-Zhou

2012-01-01

Full Text Available The combination of the method of moment, characterizing the particle population balance, and the computational fluid dynamics has been an emerging research issue in the studies on the aerosol science and on the multiphase flow science. The difficulty of solving the moment equation arises mainly from the closure of some fractal moment variables which appears in the transform from the non-linear integral-differential population balance equation to the moment equations. Within the Taylor-expansion moment method, the breakage-dominated Taylor-expansion moment equation is first derived here when the symmetric fragmentation mechanism is involved. Due to the high efficiency and the high precision, this proposed moment model is expected to become an important tool for solving population balance equations.

LAS CIUDADES EN EL CINE DE ALFRED HITCHCOCK. UNA APROXIMACIÓN A LOS ESTUDIOS FÍLMICOS DESDE EL AMBITO DE LA GEOGRAFÍA

Directory of Open Access Journals (Sweden)

Aurelio Nieto Codina

2015-01-01

Full Text Available En este artículo se proponen pautas en relación a la influencia de lo audiovisual en nuestra percepción de la ciudad, seleccionando para este objetivo algunas películas de Alfred Hitchcock. La relación del cineasta con la ciudad es ambivalente, unas veces muestra la ciudad como fuente de referencias emblemáticas, mientras en otros casos no duda en estigmatizar la ciudad tradicional compacta (centros urbanos tradicionales y apostar por modelos de urbanismo extensivo (periferias urbanas. Se describe también una nueva forma de turismo urbano, que explota los escenarios que aparecen en las películas como recurso turístico.Abstract. In this paper we propose guidelines regarding the influence of the audiovisual in our perception of the city, selecting for this purpose some of Alfred Hitchcock´s movies. The filmmaker's relationship with the city is ambivalent, sometimes shows the city as a source of symbolic references, while in other cases does not hesitate to stigmatize traditional compact city (downtowns and go for extensive planning models (suburb. It also describes a new form of urban tourism that exploits the scenarios that appear in movies as a tourism resource.

Rayleigh-Taylor instability of a self-similar spherical expansion

International Nuclear Information System (INIS)

Bernstein, I.B.; Book, D.L.

1978-01-01

The self-similar motion of a spherically symmetric isentropic cloud of ideal gas driven outward by an expanding low-density medium (e.g., radiation pressure from a pulsar) is shown to be unstable to Rayleigh-Taylor modes which develop in the neighborhood of the interface. A complete solution of the linearized equations of motion is obtained. The implications for astrophysical phenomena are discussed

Capturing the will: Imposture, delusion, and exposure in Alfred Russel Wallace's defence of spirit photography.

Science.gov (United States)

Mitchell, Benjamin David

2014-06-01

The co-discoverer of natural selection, Alfred Russel Wallace, found himself deeply embroiled in a range of controversies surrounding the relationship between science and spiritualism. At the heart of these controversies lay a crisis of evidence in cases of delusion or imposture. He had the chance to observe the many epistemic impasses brought about by this crisis while participating in the trial of the American medium Henry Slade, and through his exchanges with the physiologist William Benjamin Carpenter and the psychical researcher Frederic Myers. These contexts help to explain the increasing value that Wallace placed on the evidence of spirit photography. He hoped that it could simultaneously break these impasses, while answering once and for all the interconnected questions of the unity of the psyche and the reliability of human observation. Copyright © 2014 Elsevier Ltd. All rights reserved.

On stabilization of the Rayleigh-Taylor instability for the imploding liner on account of ion-ion collisions

International Nuclear Information System (INIS)

Gordeev, Alexander V.

2002-01-01

The stabilization of the Rayleigh-Taylor instability for the imploding cylindrical liner in the limit of a low plasma density Π ω pi 2 δ2/c2 << 1 (δ -- the characteristic size of the current layer) is investigated, when the electron currents are much greater than the ion currents. The stabilization of the Rayleigh-Taylor instability for the parameter diapason νii/ωBi < (Z2M/m)1/2 is considered, when the plasma dissipation connected with the ion-ion collisions considerably superior the usual dissipation due to the electron-ion collisions. For the electric conductivity, caused by the ion-ion collisions and resulted in the minimum value σ ∼ enc/B, the effect of the partial stabilization of the Rayleigh-Taylor instability is demonstrated

On the CFD Analysis of a Stratified Taylor-Couette System Dedicated to the Fabrication of Nanosensors

Directory of Open Access Journals (Sweden)

Duccio Griffini

2017-02-01

Full Text Available Since the pioneering work of Taylor, the analysis of flow regimes of incompressible, viscous fluids contained in circular Couette systems with independently rotating cylinders have charmed many researchers. The characteristics of such kind of flows have been considered for some industrial applications. Recently, Taylor-Couette flows found an innovative application in the production of optical fiber nanotips, to be used in molecular biology and medical diagnostic fields. Starting from the activity of Barucci et al., the present work concerns the numerical analysis of a Taylor-Couette system composed by two coaxial counter-rotating cylinders with low aspect ratio and radius ratio, filled with three stratified fluids. An accurate analysis of the flow regimes is performed, considering both the variation of inner and outer rotational speed and the reduction of fiber radius due to etching process. The large variety of individuated flow configurations provides useful information about the possible use of the Taylor-Couette system in a wide range of engineering applications. For the present case, the final objective is to provide accurate information to manufacturers of fiber nanotips about the expected flow regimes, thus helping them in the setup of the control process that will be used to generate high-quality products.

Taylor-Couette fluid flow with force oscillation in the inner-cylinder using the immersed boundary method

Energy Technology Data Exchange (ETDEWEB)

Borges, Jonatas Emmanuel; Lourenco, Marcos Antonio de Souza; Padilla, Elie Luis Martinez; Silveira Neto, Aristeu da [Federal University of Uberlandia , MG (Brazil)], e-mails: lourenco@mecanica.ufu.br, epadilla@mecanica.ufu.br, aristeus@mecanica.ufu.br; Leibsohn, Andre Martins [CENPES/Petrobras, Rio de Janeiro, RJ (Brazil)], e-mail: aleibsohn@petrobras.com

2010-07-01

As new challenges arise in the exploration of deep and ultra-deep water oil fields by PETROBRAS more knowledge and research are needed, so that tools could be developed to assist in the critical operations and make things practicable. In the context of the drilling process, the complexity of the fluid flow inside the riser is associated with the nature of the non-Newtonian flow, immersed solid particles, variable eccentricity and the superimposed traveling azimuthal waves on the inflow and outflow boundaries of the Taylor vortices. This work presents the numerical three-dimensional results of the following simplified fluid flows: Taylor-Couette, Taylor-Couette with varying imposed eccentricity and Taylor-Couette with forced oscillation in the inner cylinder. Using the Navier-Stokes equations, a finite volume method discretization with second order accuracy in both time and space was utilized to simulate the Newtonian, single-phase incompressible fluid flow in the three cases. The circular walls of the inner and outer cylinders are represented by the immersed boundary method, with the direct multi-forcing model. The determined results allow to evidence the flow structures in the three cases in a very qualitative way, even so in the presence of the inner cylinder oscillation. (author)

RADIATIVE RAYLEIGH-TAYLOR INSTABILITIES

International Nuclear Information System (INIS)

Jacquet, Emmanuel; Krumholz, Mark R.

2011-01-01

We perform analytic linear stability analyses of an interface separating two stratified media threaded by a radiation flux, a configuration relevant in several astrophysical contexts. We develop a general framework for analyzing such systems and obtain exact stability conditions in several limiting cases. In the optically thin, isothermal regime, where the discontinuity is chemical in nature (e.g., at the boundary of a radiation pressure-driven H II region), radiation acts as part of an effective gravitational field, and instability arises if the effective gravity per unit volume toward the interface overcomes that away from it. In the optically thick a diabaticregime where the total (gas plus radiation) specific entropy of a Lagrangian fluid element is conserved, for example at the edge of radiation pressure-driven bubble around a young massive star, we show that radiation acts like a modified equation of state and derive a generalized version of the classical Rayleigh-Taylor stability condition.

Alfred Nobel and His Prizes: From Dynamite to DNA.

Science.gov (United States)

Lichtman, Marshall A

2017-07-01

Alfred Nobel was one of the most successful chemists, inventors, entrepreneurs, and businessmen of the late nineteenth century. In a decision later in life, he rewrote his will to leave virtually all his fortune to establish prizes for persons of any nationality who made the most compelling achievement for the benefit of mankind in the fields of chemistry, physics, physiology or medicine, literature, and peace among nations. The prizes were first awarded in 1901, five years after his death. In considering his choice of prizes, it may be pertinent that he used the principles of chemistry and physics in his inventions and he had a lifelong devotion to science, he suffered and died from severe coronary and cerebral atherosclerosis, and he was a bibliophile, an author, and mingled with the literati of Paris. His interest in harmony among nations may have derived from the effects of the applications of his inventions in warfare ("merchant of death") and his friendship with a leader in the movement to bring peace to nations of Europe. After some controversy, including Nobel's citizenship, the mechanisms to choose the laureates and make four of the awards were developed by a foundation established in Stockholm; the choice of the laureate for promoting harmony among nations was assigned to the Norwegian Storting, another controversy. The Nobel Prizes after 115 years remain the most prestigious of awards. This review describes the man, his foundation, and the prizes with a special commentary on the Nobel Prize in Physiology or Medicine.

Taylorism given a helping hand

DEFF Research Database (Denmark)

Tolsby, June

2000-01-01

of the IT system was perceived by some of the employees. Shows how, instead of increasing employees' work engagement, the IT system had the opposite effect. Demonstrates that the new It system contributed to a deskilling of the employees, to a more task-oriented approach to their work, and to increased employees......Illustrates how th implementation of a major information technology (IT) system within the Norwegian Army affected the way the employees perceived their flexibility and personal involvement in their work. By employing Taylor's initial works, this paper illustrates how the introduction......' interdependence. Instead of increasing employees' personal flexibility and involvement in their jobs, the research shows how the new IT system in fact contributed to a reduction in the freedom to choose when and how quickly to do their jobs....

Suppression of the Rayleigh-Taylor instability due to self-radiation in a multiablation target

International Nuclear Information System (INIS)

Fujioka, Shinsuke; Sunahara, Atsushi; Nishihara, Katsunobu; Johzaki, Tomoyuki; Shiraga, Hiroyuki; Shigemori, Keisuke; Nakai, Mitsuo; Ikegawa, Tadashi; Murakami, Masakatsu; Nagai, Keiji; Norimatsu, Takayoshi; Azechi, Hiroshi; Yamanaka, Tatsuhiko; Ohnishi, Naofumi

2004-01-01

A scheme to suppress the Rayleigh-Taylor instability has been investigated for a direct-drive inertial fusion target. In a high-Z doped-plastic target, two ablation surfaces are formed separately--one driven by thermal radiation and the other driven by electron conduction. The growth of the Rayleigh-Taylor instability is significantly suppressed on the radiation-driven ablation surface inside the target due to the large ablation velocity and long density scale length. A significant reduction of the growth rate was observed in simulations and experiments using a brominated plastic target. A new direct-drive pellet was designed using this scheme

Local Nusselt number enhancement during gas-liquid Taylor bubble flow in a square mini-channel: An experimental study

International Nuclear Information System (INIS)

Majumder, Abhik; Mehta, Balkrishna; Khandekar, Sameer

2013-01-01

Taylor bubble flow takes place when two immiscible fluids (liquid-liquid or gas-liquid) flow inside a tube of capillary dimensions within specific range of volume flow ratios. In the slug flows where gas and liquid are two different phases, liquid slugs are separated by elongated Taylor bubbles. This singular flow pattern is observed in many engineering mini-/micro-scale devices like pulsating heat pipes, gas-liquid-solid monolithic reactors, micro-two-phase heat exchangers, digital micro-fluidics, micro-scale mass transfer process, fuel cells, etc. The unique and complex flow characteristics require understanding on local, as well as global, spatio-temporal scales. In the present work, the axial stream-wise profile of the fluid and wall temperature for air-water (i) isolated single Taylor bubble and, (ii) a train of Taylor bubbles, in a horizontal square channel of size 3.3 mm x 3.3 mm x 350 mm, heated from the bottom (heated length = 175 mm), with the other three sides kept insulated, are reported at different gas volume flow ratios. The primary aim is to study the enhancement of heat transfer due to the Taylor bubble train flow, in comparison with thermally developing single-phase flows. Intrusion of a bubble in the liquid flow drastically changes the local temperature profiles. The axial distribution of time-averaged local Nusselt number (Nu z ) shows that Taylor bubble train regime increases the transport of heat up to 1.2-1.6 times more as compared with laminar single-phase liquid flow. In addition, for a given liquid flow Reynolds number, the heat transfer enhancement is a function of the geometrical parameters of the unit cell, i.e., the length of adjacent gas bubble and water plug. (authors)

N TAALTOETS EVALUEER? M. Viljoen Venda Onderwyskollege ...

African Journals Online (AJOL)

Swain 1985: 35-38; Canale en Swain 1980), en daarna sal die Bachman-model van .... morfologie, sintaksis, semantiek, spelling en fonologie (Canale 1983: 7; Canale en. Swain 1980: 29). Sosiolinguistiese kompetensie is die kennis waaroor die ...... "The structure of foreign language competence," in Hughs and Porter.

Rayleigh-Taylor instability in a visco-plastic fluid

International Nuclear Information System (INIS)

Demianov, A Yu; Doludenko, A N; Son, E E; Inogamov, N A

2010-01-01

The Rayleigh-Taylor and Richtmyer-Meshkov instabilities of a visco-plastic fluid are discussed. The Bingham model is used as an effective rheological model which takes into account plastic effects. For the purposes of numerical simulation a one-mode disturbance of the contact surface between two fluids is considered. The main goal of this work is to construct numerical 2D and 3D models and to obtain the relationship between yield stress and the development of instability.

Rayleigh-Taylor instability in a visco-plastic fluid

Science.gov (United States)

Demianov, A. Yu; Doludenko, A. N.; Inogamov, N. A.; Son, E. E.

2010-12-01

The Rayleigh-Taylor and Richtmyer-Meshkov instabilities of a visco-plastic fluid are discussed. The Bingham model is used as an effective rheological model which takes into account plastic effects. For the purposes of numerical simulation a one-mode disturbance of the contact surface between two fluids is considered. The main goal of this work is to construct numerical 2D and 3D models and to obtain the relationship between yield stress and the development of instability.

Mixing and axial dispersion in Taylor-Couette flow: experimental and numerical study

International Nuclear Information System (INIS)

Nemri, M.

2013-01-01

Taylor-Couette flows between two concentric cylinders have great potential applications in chemical engineering. They are particularly convenient for two-phase small scale devices enabling solvent extraction operations. An experimental device was designed with this idea in mind. It consists of two concentric cylinders with the inner one rotating and the outer one fixed. Taylor-Couette flows take place in the annular gap between them, and are known to evolve towards turbulence through a sequence of successive instabilities. Macroscopic quantities, such as axial dispersion and mixing index, are extremely sensitive to these flow structures, which may lead to flawed modelling of the coupling between hydrodynamics and mass transfer. This particular point has been studied both experimentally and numerically. The flow and mixing have been characterized by means of flow visualization and simultaneous PIV (Particle Imaging Velocimetry) and PLIF (Planar Laser Induced Fluorescence) measurements. PLIF visualizations showed clear evidences of different transport mechanisms including 'intra-vortex mixing' and 'inter-vortex mixing'. Under WVF and MWVF regimes, intra-vortex mixing is controlled by chaotic advection, due to the 3D nature of the flow, while inter-vortex transport occurs due to the presence of waves between neighboring vortices. The combination of these two mechanisms results in enhanced axial dispersion. We showed that hysteresis may occur between consecutive regimes depending on flow history and this may have a significant effect on mixing for a given Reynolds number. The axial dispersion coefficient Dx evolution along the successive flow states was investigated thanks to dye Residence Time Distribution measurements (RTD) and particle tracking (DNS). Both experimental and numerical results have confirmed the significant effect of the flow structure and history on axial dispersion. Our study confirmed that the commonly used 1-parameter chemical engineering models (e

Adult-onset epilepsy in focal cortical dysplasia of Taylor type

NARCIS (Netherlands)

Siegel, A. M.; Cascino, G. D.; Elger, C. E.; Devinsky, O.; Laff, R.; Najjar, S.; Sperling, M. R.; LoRusso, G.; Cossu, M.; Urbach, H.; Aronica, E.; Meyer, F. B.; Scheithauer, B. W.; Dubeau, F.; Andermann, F.

2005-01-01

Focal cortical dysplasia of Taylor type (FCDT) usually presents with seizures at an early age, whereas adult onset of epilepsy is uncommon. We reviewed the medical records of 213 patients with FCDT. In 21 patients (10%), age at seizure onset ranged from 18 to 55 years (mean 25.3). The outcome of

Alfred Russel Wallace and the destruction of island life: the Iguana tragedy.

Science.gov (United States)

Kutschera, Ulrich; Kleinhans, Simon

2013-12-01

The Galápagos Islands (Ecuador) are usually associated with the explorations and theoretical deductions of Charles Robert Darwin (1809-1882), but Alfred Russel Wallace (1823-1913) also investigated these islands and published several reports on the living world of this unique archipelago. In contrast to Darwin, Wallace described the destruction of natural ecosystems by humans and foresaw the resulting extinction of species. Here, we outline two case studies pertinent to Wallace's prediction. First, we summarize the behavior of the predator-naive marine iguanas (Amblyrhynchus cristatus) on the Galápagos Islands, which are threatened by feral dogs and cats imported by humans. We also describe the unique life cycle of the spiny-tailed iguana (Ctenosaura bakeri) from the island of Utila (Honduras), a rare species whose populations are declining because of habitat destructions. In contrast to these threatened, endemic island species, the Green iguana (Iguana iguana) is still widely distributed, although, as a result of de-forestation, in some areas of South America local populations have disappeared. We conclude that Wallace was correct in his prediction that, because of human activities, numerous species of animals and plants will be driven to extinction, notably on islands.

Rayleigh-Taylor and wind-driven instabilities of the nighttime equatorial ionosphere

International Nuclear Information System (INIS)

Chiu, Y.T.; Straus, J.M.

1979-01-01

We have made a thorough re-examination of the Rayleigh-Taylor instability in the nighttime equatorial ionosphere from approx.100 km to the bottomside F region. We have taken into account explicitly the following effects which have been ignored by other workers in various combinations: (1) The eastward drift of the ionosphere caused by the nighttime polarization electric field, (2) the eastward nighttime neutral wind, and (3) recombination in the F and E regions. We found that, well below the bottomside F region, the Rayleigh-Taylor mode can be unstable and is driven by an eastward neutral wind rather than by gravitational drift. Formation of ionospheric bubbles below the bottomside F region is consistent with the observation of lower ionospheric ions in F region ionospheric holes; furthermore, seasonal and shorter term variations in spread-F occurrence may be associated with variations in the neutral wind and polarization electric field

Neumayer III and Kohnen Station in Antarctica operated by the Alfred Wegener Institute

Directory of Open Access Journals (Sweden)

Christine Wesche

2016-08-01

Full Text Available The Alfred Wegener Institute operates two stations in Dronning Maud Land, Antarctica. The German overwintering station Neumayer III is located on the Ekström Ice Shelf at 70°40’S and 08°16’W and is the logistics base for three long-term observatories (meteorology, air chemistry and geophysics and nearby research activities. Due to the vicinity to the coast (ca. 20 km from the ice shelf edge, the Neumayer III Station is the junction for many German Antarctic expeditions, especially as the starting point for the supply traverse for the second German station Kohnen. The summer station Kohnen is located about 600 km from the coast and 750 km from Neumayer III Station on the Antarctic plateau at 75°S and 00°04’E. It was erected as the base for the deep-drilling ice core project, which took place between 2001 and 2006. Since then Kohnen Station is used as a logistics base for different research projects.

Identification of Dynamic Loads Based on Second-Order Taylor-Series Expansion Method

Directory of Open Access Journals (Sweden)

Xiaowang Li

2016-01-01

Full Text Available A new method based on the second-order Taylor-series expansion is presented to identify the structural dynamic loads in the time domain. This algorithm expresses the response vectors as Taylor-series approximation and then a series of formulas are deduced. As a result, an explicit discrete equation which associates system response, system characteristic, and input excitation together is set up. In a multi-input-multi-output (MIMO numerical simulation study, sinusoidal excitation and white noise excitation are applied on a cantilever beam, respectively, to illustrate the effectiveness of this algorithm. One also makes a comparison between the new method and conventional state space method. The results show that the proposed method can obtain a more accurate identified force time history whether the responses are polluted by noise or not.

Effect of resistivity on the Rayleigh-Taylor instability in an accelerated plasma

International Nuclear Information System (INIS)

Castillo, J.L.; Huerta, M.A.

1993-01-01

We study the Rayleigh-Taylor instability in finite-conductivity accelerated plasma arcs of the type found in electromagnetic rail launchers. For a plasma of length l, acceleration a, and thermal speed v T we consider the case where v T 2 /al much-gt 1, which is valid when the projectile mass is large compared to the plasma mass. The conductivity σ enters via a magnetic Reynolds number R=σμ(al 3 ) 1/2 . The fourth-order mode equation is solved analytically using an asymptotic WKB expansion in 1/R. We find the first-order 1/R correction to the classical Rayleigh-Taylor dispersion relation for large wave number K but with K much-lt R 2 /l. The analytical results show good agreement with previous numerical calculations

James Taylor (1859-1946): favourite disciple of Hughlings Jackson and William Gowers.

Science.gov (United States)

Eadie, M J

2013-01-01

In neurological circles today the name James Taylor (1859-1946) is probably remembered mainly for his role in editing the Selected Writings of John Hughlings Jackson, the most readily available source of Jackson's contributions to neurological knowledge. Taylors' own neurological achievements are largely or entirely forgotten, but in his day he was an influential figure whose career linked the great figures of the golden era of late nineteenth century British neurology to the neurology of the first half of the twentieth century. Not only was he a junior professional colleague and close friend of both John Hughlings Jackson and William Gowers, he also produced a substantial corpus of neurological writings in his own right, including a textbook of child neurology and the first English language account of subacute combined degeneration of the spinal cord.

The Rayleigh-Taylor instability in a self-gravitating two-layer viscous sphere

Science.gov (United States)

Mondal, Puskar; Korenaga, Jun

2018-03-01

The dispersion relation of the Rayleigh-Taylor instability in the spherical geometry is of profound importance in the context of the Earth's core formation. Here we present a complete derivation of this dispersion relation for a self-gravitating two-layer viscous sphere. Such relation is, however, obtained through the solution of a complex transcendental equation, and it is difficult to gain physical insights directly from the transcendental equation itself. We thus also derive an empirical formula to compute the growth rate, by combining the Monte Carlo sampling of the relevant model parameter space with linear regression. Our analysis indicates that the growth rate of Rayleigh-Taylor instability is most sensitive to the viscosity of inner layer in a physical setting that is most relevant to the core formation.

Measurement of local heat transfer coefficient during gas–liquid Taylor bubble train flow by infra-red thermography

International Nuclear Information System (INIS)

Mehta, Balkrishna; Khandekar, Sameer

2014-01-01

Highlights: • Infra-red thermographic study of Taylor bubble train flow in square mini-channel. • Design of experiments for measurement of local streamwise Nusselt number. • Minimizing conjugate heat transfer effects and resulting errors in data reduction. • Benchmarking against single-phase flow and three-dimensional computations. • Local heat transfer enhancement up to two times due to Taylor bubble train flow. -- Abstract: In mini/micro confined internal flow systems, Taylor bubble train flow takes place within specific range of respective volume flow ratios, wherein the liquid slugs get separated by elongated Taylor bubbles, resulting in an intermittent flow situation. This unique flow characteristic requires understanding of transport phenomena on global, as well as on local spatio-temporal scales. In this context, an experimental design methodology and its validation are presented in this work, with an aim of measuring the local heat transfer coefficient by employing high-resolution InfraRed Thermography. The effect of conjugate heat transfer on the true estimate of local transport coefficients, and subsequent data reduction technique, is discerned. Local heat transfer coefficient for (i) hydrodynamically fully developed and thermally developing single-phase flow in three-side heated channel and, (ii) non-boiling, air–water Taylor bubble train flow is measured and compared in a mini-channel of square cross-section (5 mm × 5 mm; D h = 5 mm, Bo ≈ 3.4) machined on a stainless steel substrate (300 mm × 25 mm × 11 mm). The design of the setup ensures near uniform heat flux condition at the solid–fluid interface; the conjugate effects arising from the axial back conduction in the substrate are thus minimized. For benchmarking, the data from single-phase flow is also compared with three-dimensional computational simulations. Depending on the employed volume flow ratio, it is concluded that enhancement of nearly 1.2–2.0 times in time

The mitigation effect of sheared axial flow on the rayleigh-taylor instability in Z-pinch plasma

International Nuclear Information System (INIS)

Zhang Yang

2005-01-01

A magnetohydrodynamic formulation is derived to investigate the mitigation effects of the sheared axial flow on the Rayleigh-Taylor (RT) instability in Z-pinch plasma. The dispersion relation of the compressible model is given. The mitigation effects of sheared axial flow on the Rayleigh-Taylor instability of Z-pinch plasma in the compressible and incompressible models are compared respectively, and the effect of compressible on the instability of system with sheared axial flow is discussed. It is found that, compressibility effects can stabilize the Rayleigh-Taylor/Kelvin-Helmholtz (RT/KH) instability, and this allows the sheared axial flow mitigate the RT instability far more effectively. The authors also find that, at the early stage of the implosion, if the temperature of the plasma is not very high, the compressible model is much more suitable to describing the state of system than the incompressible one. (author)

Inertial migration of particles in Taylor-Couette flows

Science.gov (United States)

Majji, Madhu V.; Morris, Jeffrey F.

2018-03-01

An experimental study of inertial migration of neutrally buoyant particles in the circular Couette flow (CCF), Taylor vortex flow (TVF) and wavy vortex flow (WVF) is reported. This work considers a concentric cylinder Taylor-Couette device with a stationary outer cylinder and rotating inner cylinder. The device has a radius ratio of η = ri/ro = 0.877, where ri and ro are the inner and outer radii of the flow annulus. The ratio of the annular width between the cylinders (δ = ro - ri) and the particle diameter (dp) is α = δ/dp = 20. For η = 0.877, the flow of a Newtonian fluid undergoes transitions from CCF to TVF and TVF to WVF at Reynolds numbers Re = 120 and 151, respectively, and for the dilute suspensions studied here, these critical Reynolds numbers are almost unchanged. In CCF, particles were observed to migrate, due to the competition between the shear gradient of the flow and the wall interactions, to an equilibrium location near the middle of the annulus with an offset toward the inner cylinder. In TVF, the vortex motion causes the particles to be exposed to the shear gradient and wall interactions in a different manner, resulting in a circular equilibrium region in each vortex. The radius of this circular region grows with increase in Re. In WVF, the azimuthal waviness results in fairly well-distributed particles across the annulus.

Bifurcating fronts for the Taylor-Couette problem in infinite cylinders

Science.gov (United States)

Hărăguş-Courcelle, M.; Schneider, G.

We show the existence of bifurcating fronts for the weakly unstable Taylor-Couette problem in an infinite cylinder. These fronts connect a stationary bifurcating pattern, here the Taylor vortices, with the trivial ground state, here the Couette flow. In order to show the existence result we improve a method which was already used in establishing the existence of bifurcating fronts for the Swift-Hohenberg equation by Collet and Eckmann, 1986, and by Eckmann and Wayne, 1991. The existence proof is based on spatial dynamics and center manifold theory. One of the difficulties in applying center manifold theory comes from an infinite number of eigenvalues on the imaginary axis for vanishing bifurcation parameter. But nevertheless, a finite dimensional reduction is possible, since the eigenvalues leave the imaginary axis with different velocities, if the bifurcation parameter is increased. In contrast to previous work we have to use normalform methods and a non-standard cut-off function to obtain a center manifold which is large enough to contain the bifurcating fronts.

Alfred Owre: revisiting the thought of a distinguished, though controversial, early twentieth-century dental educator.

Science.gov (United States)

Nash, David A

2013-08-01

Many in dental education are unfamiliar with the professional life and thought of Dr. Alfred Owre, a distinguished though controversial dental educator in the early twentieth century. Owre served as dean of dentistry at both the University of Minnesota, 1905-27, and Columbia University, 1927-33. He was also a member of the Carnegie Foundation's commission that developed the report Dental Education in the United States and Canada, written by Dr. William J. Gies. Owre was a controversial leader due to his creative and original ideas that challenged dental education and the profession. His assessment and critique of the problems of dental education in his era can readily be applied to contemporary dental education and the profession, just as his vision for transformative change resonates with ideas that continue to be advocated by some individuals today. This article also documents his tumultuous relationship with Gies.

Bias Correction with Jackknife, Bootstrap, and Taylor Series

OpenAIRE

Jiao, Jiantao; Han, Yanjun; Weissman, Tsachy

2017-01-01

We analyze the bias correction methods using jackknife, bootstrap, and Taylor series. We focus on the binomial model, and consider the problem of bias correction for estimating $f(p)$, where $f \\in C[0,1]$ is arbitrary. We characterize the supremum norm of the bias of general jackknife and bootstrap estimators for any continuous functions, and demonstrate the in delete-$d$ jackknife, different values of $d$ may lead to drastically different behavior in jackknife. We show that in the binomial ...

Slavnov-Taylor1.0: A Mathematica package for computation in BRST formalism

CERN Document Server

Picariello, Marco; Picariello, Marco; Torrente-Lujan, Emilio

2004-01-01

Slavnov-Taylor1.0 is a Mathematica package which allows us to perform automatic simbolic computation in BRST formalism. This article serves as a self-contained guide to prospective users, and indicates the conventions and approximations used.

On Taylor-Series Approximations of Residual Stress

Science.gov (United States)

Pruett, C. David

1999-01-01

Although subgrid-scale models of similarity type are insufficiently dissipative for practical applications to large-eddy simulation, in recently published a priori analyses, they perform remarkably well in the sense of correlating highly against exact residual stresses. Here, Taylor-series expansions of residual stress are exploited to explain the observed behavior and "success" of similarity models. Until very recently, little attention has been given to issues related to the convergence of such expansions. Here, we re-express the convergence criterion of Vasilyev [J. Comput. Phys., 146 (1998)] in terms of the transfer function and the wavenumber cutoff of the grid filter.

Nonlinear saturation of the Rayleigh Taylor instability

International Nuclear Information System (INIS)

Das, A.; Mahajan, S.; Kaw, P.; Sen, A.; Benkadda, S.; Verga, A.

1997-01-01

The problem of the nonlinear saturation of the 2 dimensional Rayleigh Taylor instability is re-examined to put various earlier results in a proper perspective. The existence of a variety of final states can be attributed to the differences in the choice of boundary conditions and initial conditions in earlier numerical modeling studies. Our own numerical simulations indicate that the RT instability saturates by the self consistent generation of shear flow even in situations (with periodic boundaries) where, in principle, an infinite amount of gravitational energy can be tapped. Such final states can be achieved for suitable values of the Prandtl number. (author)

Method of generalized coordinates and an application to Rayleigh-Taylor instability

International Nuclear Information System (INIS)

Dienes, J.K.

1978-01-01

The method of generalized coordinates is extended to the analysis of continuous bodies for which the degrees of freedom are independent velocity distributions in the spatial coordinates. The corresponding Lagrange equations contain generalized convective terms as well as the usual generalized forces and masses. Since the existence of a potential is not assumed, the equations of motion can be applied to media with arbitrary (possible dissipative) constitutive laws. Material deformation is characterized by the rate of strain, which is taken as the symmetric part of the velocity gradient, making the approach valid for arbitrarily large deformations. As an example, infinitesimal Rayleigh-Taylor instability is considered by analytic methods. Then, large amplitude Rayleigh-Taylor instability is represented with a single-degree-of-freedom analysis that shows the development (by numerical integration) of the known spike-and-bubble configuration of the unstable interface. The infinitesimal stability of a plastically deforming solid and the growth of the instability to large amplitudes are also considered

Solution of the agglomerate Brownian coagulation using Taylor-expansion moment method.

Science.gov (United States)

Yu, Mingzhou; Lin, Jianzhong

2009-08-01

The newly proposed Taylor-expansion moment method (TEMOM) is extended to solve agglomerate coagulation in the free-molecule regime and in the continuum regime, respectively. The moment equations with respect to fractal dimension are derived based on 3rd Taylor-series expansion technique. The validation of this method is done by comparing its result with the published data at each limited size regime. By comparing with analytical method, sectional method (SM) and quadrature method of moments (QMOMs), this new approach is shown to produce the most efficiency without losing much accuracy. At each limited size regime, the effect of fractal dimension on the decay of particle number and particle size growth is mainly investigated, and especially in the continuum regime the relation of mean diameters of size distributions with different fractal dimensions is first proposed. The agglomerate size distribution is found to be sensitive to the fractal dimension and the initial geometric mean deviation before the self-preserving size distribution is achieved in the continuum regime.

Taylor's Theorem: The Elusive "c" Is Not So Elusive

Science.gov (United States)

Kreminski, Richard

2010-01-01

For a suitably nice, real-valued function "f" defined on an open interval containing [a,b], f(b) can be expressed as p[subscript n](b) (the nth Taylor polynomial of f centered at a) plus an error term of the (Lagrange) form f[superscript (n+1)](c)(b-a)[superscript (n+1)]/(n+1)! for some c in (a,b). This article is for those who think that not…

Interpreted Modernity. Weber and Taylor on Values and Modernity

OpenAIRE

Reckling, Falk

2001-01-01

The writings of Weber and Taylor have some strong affinities. Both start from the anthropological idea that man evaluates his position in the world and constitutes the social world by values. Their analyses of values aim at an understanding of those intersubjective meanings that have constituted western modernity. But, at the same time, their anthropological starting point leads to different interpretations of modernity. Historically, both argue that rationalization (as instrumental rationali...

Effect of gas expansion on the front shape of a Taylor bubble: an experimental contribution

Directory of Open Access Journals (Sweden)

Santos Laura

2014-03-01

Full Text Available An experimental study where an individual Taylor bubble rises through water with different bubble volume expansion rates is presented with the (front bubble shape determination as main objective. A combination of two techniques, Particle Image Velocimetry (PIV and Pulsed Shadowgraphy (PS, was used to collect images for further treatment in order to characterize the liquid flow pattern in front of the bubble and the bubble shape. Processing the images acquired with pulsed illumination from behind the bubble it was possible to define with precision the bubble shape at different stages when it was expanding. The operation conditions used allowed a wide range of volume expansion rates (0 to 28.5 × 10-6 m3/s with a significant effect on the Taylor bubble velocity; increases in bubble velocity up to 21% were observed relatively to constant volume system condition. Nevertheless, it seems that the front shape of Taylor bubbles does not change significantly with the upward liquid flow rates induced by gas expansion, at least for the volume expansion rates used in the experiments.

Designs for highly nonlinear ablative Rayleigh-Taylor experiments on the National Ignition Facility

International Nuclear Information System (INIS)

Casner, A.; Masse, L.; Liberatore, S.; Jacquet, L.; Loiseau, P.; Poujade, O.; Smalyuk, V. A.; Bradley, D. K.; Park, H. S.; Remington, B. A.; Igumenshchev, I.; Chicanne, C.

2012-01-01

We present two designs relevant to ablative Rayleigh-Taylor instability in transition from weakly nonlinear to highly nonlinear regimes at the National Ignition Facility [E. I. Moses, J. Phys.: Conf. Ser. 112, 012003 (2008)]. The sensitivity of nonlinear Rayleigh-Taylor instability physics to ablation velocity is addressed with targets driven by indirect drive, with stronger ablative stabilization, and by direct drive, with weaker ablative stabilization. The indirect drive design demonstrates the potential to reach a two-dimensional bubble-merger regime with a 20 ns duration drive at moderate radiation temperature. The direct drive design achieves a 3 to 5 times increased acceleration distance for the sample in comparison to previous experiments allowing at least 2 more bubble generations when starting from a three-dimensional broadband spectrum.

Designs for highly nonlinear ablative Rayleigh-Taylor experiments on the National Ignition Facility

Energy Technology Data Exchange (ETDEWEB)

Casner, A.; Masse, L.; Liberatore, S.; Jacquet, L.; Loiseau, P.; Poujade, O. [CEA, DAM, DIF, F-91297 Arpajon (France); Smalyuk, V. A.; Bradley, D. K.; Park, H. S.; Remington, B. A. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Igumenshchev, I. [Laboratory of Laser Energetics, University of Rochester, Rochester, New York 14623-1299 (United States); Chicanne, C. [CEA, DAM, VALDUC, F-21120 Is-sur-Tille (France)

2012-08-15

We present two designs relevant to ablative Rayleigh-Taylor instability in transition from weakly nonlinear to highly nonlinear regimes at the National Ignition Facility [E. I. Moses, J. Phys.: Conf. Ser. 112, 012003 (2008)]. The sensitivity of nonlinear Rayleigh-Taylor instability physics to ablation velocity is addressed with targets driven by indirect drive, with stronger ablative stabilization, and by direct drive, with weaker ablative stabilization. The indirect drive design demonstrates the potential to reach a two-dimensional bubble-merger regime with a 20 ns duration drive at moderate radiation temperature. The direct drive design achieves a 3 to 5 times increased acceleration distance for the sample in comparison to previous experiments allowing at least 2 more bubble generations when starting from a three-dimensional broadband spectrum.

An integral equation-based numerical solver for Taylor states in toroidal geometries

Science.gov (United States)

O'Neil, Michael; Cerfon, Antoine J.

2018-04-01

We present an algorithm for the numerical calculation of Taylor states in toroidal and toroidal-shell geometries using an analytical framework developed for the solution to the time-harmonic Maxwell equations. Taylor states are a special case of what are known as Beltrami fields, or linear force-free fields. The scheme of this work relies on the generalized Debye source representation of Maxwell fields and an integral representation of Beltrami fields which immediately yields a well-conditioned second-kind integral equation. This integral equation has a unique solution whenever the Beltrami parameter λ is not a member of a discrete, countable set of resonances which physically correspond to spontaneous symmetry breaking. Several numerical examples relevant to magnetohydrodynamic equilibria calculations are provided. Lastly, our approach easily generalizes to arbitrary geometries, both bounded and unbounded, and of varying genus.

Self-similarity in high Atwood number Rayleigh-Taylor experiments

Science.gov (United States)

Mikhaeil, Mark; Suchandra, Prasoon; Pathikonda, Gokul; Ranjan, Devesh

2017-11-01

Self-similarity is a critical concept in turbulent and mixing flows. In the Rayleigh-Taylor instability, theory and simulations have shown that the flow exhibits properties of self-similarity as the mixing Reynolds number exceeds 20000 and the flow enters the turbulent regime. Here, we present results from the first large Atwood number (0.7) Rayleigh-Taylor experimental campaign for mixing Reynolds number beyond 20000 in an effort to characterize the self-similar nature of the instability. Experiments are performed in a statistically steady gas tunnel facility, allowing for the evaluation of turbulence statistics. A visualization diagnostic is used to study the evolution of the mixing width as the instability grows. This allows for computation of the instability growth rate. For the first time in such a facility, stereoscopic particle image velocimetry is used to resolve three-component velocity information in a plane. Velocity means, fluctuations, and correlations are considered as well as their appropriate scaling. Probability density functions of velocity fields, energy spectra, and higher-order statistics are also presented. The energy budget of the flow is described, including the ratio of the kinetic energy to the released potential energy. This work was supported by the DOE-NNSA SSAA Grant DE-NA0002922.

Taylor-series method for four-nucleon wave functions

International Nuclear Information System (INIS)

Sandulescu, A.; Tarnoveanu, I.; Rizea, M.

1977-09-01

Taylor-series method for transforming the infinite or finite well two-nucleon wave functions from individual coordinates to relative and c.m. coordinates, by expanding the single particle shell model wave functions around c.m. of the system, is generalized to four-nucleon wave functions. Also the connections with the Talmi-Moshinsky method for two and four harmonic oscillator wave functions are deduced. For both methods Fortran IV programs for the expansion coefficients have been written and the equivalence of corresponding expressions numerically proved. (author)

Resurrecting Democracies : Secularity Recast in Charles Taylor, Paul Valadier, and Joseph Ratzinger

NARCIS (Netherlands)

Ossewaarde-Lowtoo, Roshnee

In this article, the alternative conception of secularity of Charles Taylor, Paul Valadier and Joseph Ratzinger (former Benedict XVI) is explored. A secularized society, which they take as an established condition, does not necessarily exclude religion, Christianity or Christian transcendence, in

Taylor-plasticity-based analysis of length scale effects in void growth

KAUST Repository

Liu, Junxian

2014-09-25

We have studied the void growth problem by employing the Taylor-based strain gradient plasticity theories, from which we have chosen the following three, namely, the mechanism-based strain gradient (MSG) plasticity (Gao et al 1999 J. Mech. Phys. Solids 47 1239, Huang et al 2000 J. Mech. Phys. Solids 48 99-128), the Taylor-based nonlocal theory (TNT; 2001 Gao and Huang 2001 Int. J. Solids Struct. 38 2615) and the conventional theory of MSG (CMSG; Huang et al 2004 Int. J. Plast. 20 753). We have addressed the following three issues which occur when plastic deformation at the void surface is unconstrained. (1) Effects of elastic deformation. Elasticity is essential for cavitation instability. It is therefore important to guarantee that the gradient term entering the Taylor model is the effective plastic strain gradient instead of the total strain gradient. We propose a simple elastic-plastic decomposition method. When the void size approaches the minimum allowable initial void size related to the maximum allowable geometrically necessary dislocation density, overestimation of the flow stress due to the negligence of the elastic strain gradient is on the order of lεY/R0 near the void surface, where l, εY and R0 are, respectively, the intrinsic material length scale, the yield strain and the initial void radius. (2) MSG intrinsic inconsistency, which was initially mentioned in Gao et al (1999 J. Mech. Phys. Solids 47 1239) but has not been the topic of follow-up studies. We realize that MSG higher-order stress arises due to the linear-strain-field approximation within the mesoscale cell with a nonzero size, lε. Simple analysis shows that within an MSG mesoscale cell near the void surface, the difference between microscale and mesoscale strains is on the order of (lε/R0)2, indicating that when lε/R0 ∼ 1.0, the higher-order stress effect can make the MSG result considerably different from the TNT or CMSG results. (3) Critical condition for cavitation instability

Theoretical and numerical study of Rayleigh-Taylor instabilities in magnetized plasmas

International Nuclear Information System (INIS)

Andrei, A. Ivanov

2001-06-01

In this thesis we're studying both the general case of the 'classic' Rayleigh-Taylor instability (in incompressible fluids) and more specific cases of the instabilities of Rayleigh-Taylor type in magnetized plasmas, in the liners or wire array implosions etc. We have studied the influence of the Hall diffusion of magnetic field on the growth rate of the instability. We have obtained in this work a self-similar solution for the widening of the initial profile of the magnetic field and for the wave of the penetration of magnetic field. After that the subsequent evolution of the magnetic field in plasma opening switches (POS) has been examined. We have shown the possibility of the existence of a strong rarefaction wave for collisional and non-collisional cases. This wave can explain the phenomenon of the opening of POS. The effect of the suppression of Rayleigh-Taylor instability by forced oscillations of the boundary between two fluids permits us to propose some ideas for the experiments of inertial fusion. We have considered the general case of the instability, in other words - two incompressible viscous superposed fluids in a gravitational field. We have obtained an exact analytical expression for the growth rate and then we have analyzed the influence of the parameters of external 'pumping' on the instability. These results can be applied to a wide range of systems, starting from classic hydrodynamics and up to astrophysical plasmas. The scheme of wire arrays has become recently a very popular method to obtain a high power X-radiation or for a high quality implosion in Z-pinches. The experimental studies have demonstrated that the results of implosion are much better for the case of multiple thin wires situated cylindrically than in a usual liner scheme. We have examined the problem modeling the stabilization of Rayleigh-Taylor instability for a wire array system. The reason for instability suppression is the regular spatial modulation of the surface plasma

High-Speed Solution of Spacecraft Trajectory Problems Using Taylor Series Integration

Science.gov (United States)

Scott, James R.; Martini, Michael C.

2010-01-01

It has been known for some time that Taylor series (TS) integration is among the most efficient and accurate numerical methods in solving differential equations. However, the full benefit of the method has yet to be realized in calculating spacecraft trajectories, for two main reasons. First, most applications of Taylor series to trajectory propagation have focused on relatively simple problems of orbital motion or on specific problems and have not provided general applicability. Second, applications that have been more general have required use of a preprocessor, which inevitably imposes constraints on computational efficiency. The latter approach includes the work of Berryman et al., who solved the planetary n-body problem with relativistic effects. Their work specifically noted the computational inefficiencies arising from use of a preprocessor and pointed out the potential benefit of manually coding derivative routines. In this Engineering Note, we report on a systematic effort to directly implement Taylor series integration in an operational trajectory propagation code: the Spacecraft N-Body Analysis Program (SNAP). The present Taylor series implementation is unique in that it applies to spacecraft virtually anywhere in the solar system and can be used interchangeably with another integration method. SNAP is a high-fidelity trajectory propagator that includes force models for central body gravitation with N X N harmonics, other body gravitation with N X N harmonics, solar radiation pressure, atmospheric drag (for Earth orbits), and spacecraft thrusting (including shadowing). The governing equations are solved using an eighth-order Runge-Kutta Fehlberg (RKF) single-step method with variable step size control. In the present effort, TS is implemented by way of highly integrated subroutines that can be used interchangeably with RKF. This makes it possible to turn TS on or off during various phases of a mission. Current TS force models include central body

Charles Taylor na Haia: limites da justiça internacional?

Directory of Open Access Journals (Sweden)

IZADORA XAVIER DO MONTE

2010-11-01

Full Text Available Recentemente o julgamento de Charles Taylor, um dos protagonistas no conflito civil na Libéria, atraiu a corte internacional em Haia para o foco da comunidade internacional. Assim, o presente artigo busca delimitar as conseqüências políticas e jurídicas que advirão desse processo para a comunidade internacional como um todo.

A Study of Heat Transfer and Flow Characteristics of Rising Taylor Bubbles

Science.gov (United States)

Scammell, Alexander David

2016-01-01

Practical application of flow boiling to ground- and space-based thermal management systems hinges on the ability to predict the systems heat removal capabilities under expected operating conditions. Research in this field has shown that the heat transfer coefficient within two-phase heat exchangers can be largely dependent on the experienced flow regime. This finding has inspired an effort to develop mechanistic heat transfer models for each flow pattern which are likely to outperform traditional empirical correlations. As a contribution to the effort, this work aimed to identify the heat transfer mechanisms for the slug flow regime through analysis of individual Taylor bubbles.An experimental apparatus was developed to inject single vapor Taylor bubbles into co-currently flowing liquid HFE 7100. The heat transfer was measured as the bubble rose through a 6 mm inner diameter heated tube using an infrared thermography technique. High-speed flow visualization was obtained and the bubble film thickness measured in an adiabatic section. Experiments were conducted at various liquid mass fluxes (43-200 kgm2s) and gravity levels (0.01g-1.8g) to characterize the effect of bubble drift velocityon the heat transfer mechanisms. Variable gravity testing was conducted during a NASA parabolic flight campaign.Results from the experiments showed that the drift velocity strongly affects the hydrodynamics and heat transfer of single elongated bubbles. At low gravity levels, bubbles exhibited shapes characteristic of capillary flows and the heat transfer enhancement due to the bubble was dominated by conduction through the thin film. At moderate to high gravity, traditional Taylor bubbles provided small values of enhancement within the film, but large peaks in the wake heat transfer occurred due to turbulent vortices induced by the film plunging into the trailing liquid slug. Characteristics of the wake heat transfer profiles were analyzed and related to the predicted velocity field

COMIC AGENTS: FROM A POETIC TO AN ANTHROPOLOGICAL PARADIGM OF COMEDY (ARISTOTLE AND ALFRED GELL

Directory of Open Access Journals (Sweden)

ANNA KAWALEC

2016-05-01

Full Text Available Aristotle was concerned with the comedy genre as a kind of poetry. Its creators, the comic poets, interested him only marginally. This genological approach to its subject-matter dominated the theory and philosophy of art for subsequent centuries as evidenced by the subsequent elaborations of interpretations of Aristotle’s catharsis. The alternative approach focused instead on subjects as creators of art. As a consequence of the long-term development of anthropocentrism in the humanities, however, this approach took over. The “ performative turn” represents its more recent version. It allows one to interpret Poetics and other classical works not in the context of an object (comedy, but in the context of the acting subject. I claim that social anthropology further explores the concept of comedy and itself presumes it in its conceptual foundations and research approach. I elaborate the argument on the basis of the concept of the “spirit of comedy” coined by Alfred Gell .

Numerical analyses of a Couette-Taylor flow in the presence of a magnetic field

International Nuclear Information System (INIS)

Tagawa, T; Kaneda, M

2005-01-01

An axisymmetric Couette-Taylor flow of liquid metal in the presence of a magnetic field has been numerically studied. An inner cylinder of a coaxial container is rotating at a constant angular velocity whereas the outer cylindrical wall is at rest. An axial or a toroidal magnetic field is applied to this configuration to investigate the influence of such magnetic fields on the liquid metal Couette-Taylor flow. The toroidal magnetic field can be produced with a straight wire along the central axis in which electric current passes. The governing equations of mass conservation, momentum, Ohm's law and conservation of electric charge for an axisymmetric cylindrical coordinate system have been numerically solved with a finite difference method using the HSMAC algorithm. In the numerical analyses, since the Joule heating and the induced magnetic field are neglected, the system parameters are the Hartmann number and the Reynolds number. The numerical results reveal significant difference in the Couette-Taylor flow depending on whether the applied magnetic field is axial or toroidal as well as on the Hartmann and Reynolds numbers. The axial magnetic field damps out the secondary flow efficiently and velocity gradient in the direction of the magnetic field tends to diminish while the toroidal magnetic field does not have such an efficient damping

Rayleigh-Taylor instability in accelerated elastic-solid slabs

Science.gov (United States)

Piriz, S. A.; Piriz, A. R.; Tahir, N. A.

2017-12-01

We develop the linear theory for the asymptotic growth of the incompressible Rayleigh-Taylor instability of an accelerated solid slab of density ρ2, shear modulus G , and thickness h , placed over a semi-infinite ideal fluid of density ρ110.1007/s000330050121] to arbitrary values of AT and unveil the singular feature of an instability threshold below which the slab is stable for any perturbation wavelength. As a consequence, an accelerated elastic-solid slab is stable if ρ2g h /G ≤2 (1 -AT) /AT .

The Psychological Concepts in Taylor Swift's "Blank Space"

OpenAIRE

Anindhita, Novia Putri

2016-01-01

“Blank Space” is a song that is sung by a singer, Taylor Swift. The lyrics tell about the lonely woman who dates a lot but always fails to manage her relationship. However, it does not make her worry to start a new relationship. The purpose of this study is to analyze the elements of the poetry in the lyrics and to show the readers the psychological contents as portrayed in the music video. The study uses intrinsic and extrinsic theories to analyze the data and library research to compile the...

Analysis of weakly nonlinear three-dimensional Rayleigh--Taylor instability growth

International Nuclear Information System (INIS)

Dunning, M.J.; Haan, S.W.

1995-01-01

Understanding the Rayleigh--Taylor instability, which develops at an interface where a low density fluid pushes and accelerates a higher density fluid, is important to the design, analysis, and ultimate performance of inertial confinement fusion targets. Existing experimental results measuring the growth of two-dimensional (2-D) perturbations (perturbations translationally invariant in one transverse direction) are adequately modeled using the 2-D hydrodynamic code LASNEX [G. B. Zimmerman and W. L. Kruer, Comments Plasma Phys. Controlled Fusion 11, 51 (1975)]. However, of ultimate interest is the growth of three-dimensional (3-D) perturbations such as those initiated by surface imperfections or illumination nonuniformities. Direct simulation of such 3-D experiments with all the significant physical processes included and with sufficient resolution is very difficult. This paper addresses how such experiments might be modeled. A model is considered that couples 2-D linear regime hydrodynamic code results with an analytic model to allow modeling of 3-D Rayleigh--Taylor growth through the linear regime and into the weakly nonlinear regime. The model is evaluated in 2-D by comparison with LASNEX results. Finally the model is applied to estimate the dynamics of a hypothetical 3-D foil

Changing Course: Thurgood Marshall College Fund President Johnny Taylor Seeks New Partnerships and Avenues of Support for Public HBCUs

Science.gov (United States)

Stuart, Reginald

2011-01-01

When veteran educator Dr. N. Joyce Payne handed the reins of the organization she founded, the Thurgood Marshall College Fund, to entertainment lawyer and board member Johnny Taylor, Taylor began pursuing a remake of the prestigious group that has turned it on its head in just a matter of months. Today, with just more than a year of leading the…

Cyclic and seasonal features in the behaviour of linear growth increment of Rayleigh-Taylor instability in equatorial F-region

International Nuclear Information System (INIS)

Farkullin, M.N.; Nikitin, M.A.; Kashchenko, N.M.

1989-01-01

Calculations of linear increment of the Rayleigh-Taylor instability for various geophysical conditions are presented. It is shwn that space-time characteristics of increment depend strongly on conditions of solar activity and seasons. The calculation results are in a good agreement with statistical regularities of F-scattering observation in equatorial F-area, which points to the Rayleigh-Taylor natur of the penomena

Growth of Rayleigh-Taylor and bulk convective instabilities in dynamics of plasma liners and pinches

International Nuclear Information System (INIS)

Bud'ko, A.B.; Velikovich, A.L.; Liberman, M.A.; Felber, F.S.

1989-01-01

Perturbation growth is studied for the initial, linear stage of an instability development in the course of a cylindrically-symmetric compression and expansion of plasma liners and Z-pinches with a sharp boundary. The hydrodynamic instabilities are Rayleigh-Taylor and bulk convective ones, the former being the most dengerous. Classification of the instability modes developing in accelerated plasmas, inclusing the local and global Rayleigh-Taylor modes, is given. The spectra of the instability growth rates are calculated for plasma liners and Z-pinches. The properties of the spectra appear to explain the filamentation and stratification of plasmas observed in the experiments with liners and Z-pinches. An axial magnetic field is shown to create a window of stability in the space of the flow parameters, where th Rayleigh-Taylor modes are fully suppressed by the magnetic shear, and the bulk convective ones - to a considerable extent. The axial magnetic field required to stabilize the implosion of a liner is estimated as B z0 =(10-30 kG)I(MA)/R 0 (cm), where I is the average current, R 0 - the initial radius of the liner

The Taylor relation in compression deformed Ge single crystals

International Nuclear Information System (INIS)

Nyilas, K; Ungar, T; Dupas, C; Martin, J L; Kruml, T

2010-01-01

Ge single crystals are deformed in compression at 850K and the same strain rate to various extents of strains. In each sample, the internal stress is measured through stress reduction tests and the dislocation densities by X-ray measurements. Data about these two parameters follow fairly well the Taylor-Saada relation, provided a correction term is added. It probably corresponds to dislocations which are seen by X-rays, though they do not contribute to crystal hardening.

An experimental study of the connection between the hydrodynamic and phase-transition descriptions of the Couette-Taylor instability

International Nuclear Information System (INIS)

Berland, T.; Joessang, T.; Feder, J.

1986-04-01

The laser doppler velocimetry technique has been used to measure the radial flow velocity in the Taylor vortex flow at several Taylor numbers close to and above the critical value. The first four harmonics of the flow field have been analyzed using a model described by Davey. The analysis demonstrates that the amplitude of the first harmonic of the super-critical flow field can be regarded as the ''order parameter'' of the transition from the laminar Couette flow to the Taylor vortex flow. This transition is described by a generalized Landau theory for classical second order mean-field phase transitions. The analysis of the results of carefully performed experiments not only confirms the findings of earlier experimental work, but in addition all the significant parameters of the full Davey model for this hydrodynamic instability are determied

Two-equation and multi-fluid turbulence models for Rayleigh–Taylor mixing

International Nuclear Information System (INIS)

Kokkinakis, I.W.; Drikakis, D.; Youngs, D.L.; Williams, R.J.R.

2015-01-01

Highlights: • We present a new improved version of the K–L model. • The improved K–L is found in good agreement with the multi-fluid model and ILES. • The study concerns Rayleigh–Taylor flows at initial density ratios 3:1 and 20:1. - Abstract: This paper presents a new, improved version of the K–L model, as well as a detailed investigation of K–L and multi-fluid models with reference to high-resolution implicit large eddy simulations of compressible Rayleigh–Taylor mixing. The accuracy of the models is examined for different interface pressures and specific heat ratios for Rayleigh–Taylor flows at initial density ratios 3:1 and 20:1. It is shown that the original version of the K–L model requires modifications in order to provide comparable results to the multi-fluid model. The modifications concern the addition of an enthalpy diffusion term to the energy equation; the formulation of the turbulent kinetic energy (source) term in the K equation; and the calculation of the local Atwood number. The proposed modifications significantly improve the results of the K–L model, which are found in good agreement with the multi-fluid model and implicit large eddy simulations with respect to the self-similar mixing width; peak turbulent kinetic energy growth rate, as well as volume fraction and turbulent kinetic energy profiles. However, a key advantage of the two-fluid model is that it can represent the degree of molecular mixing in a direct way, by transferring mass between the two phases. The limitations of the single-fluid K–L model as well as the merits of more advanced Reynolds-averaged Navier–Stokes models are also discussed throughout the paper.

Stability of force-free Taylor states in a new version of magnetic flux-averaged magnetohydrodynamics

International Nuclear Information System (INIS)

Pfirsch, D.; Sudan, R.N.

1996-01-01

It is observed that the recently developed magnetic flux-averaged magnetohydrodynamics (AMHD) [Phys. Plasmas 1, 2488 (1994)] is incompatible with Taylor close-quote s theorem, which states that the lowest-energy state of force-free equilibria based on the conservation of the helicity integral is absolutely stable for vanishingly small resistivity. By a modification of the Lagrangian from which AMHD is derived, a modified version of AMHD that is compatible with Taylor close-quote s theorem is obtained. It also provides an energy principle for examining the linear instability of resistive equilibria, which has a great advantage over resistive MHD. copyright 1996 American Institute of Physics

Detection of Life Threatening Ventricular Arrhythmia Using Digital Taylor Fourier Transform.

Science.gov (United States)

Tripathy, Rajesh K; Zamora-Mendez, Alejandro; de la O Serna, José A; Paternina, Mario R Arrieta; Arrieta, Juan G; Naik, Ganesh R

2018-01-01

Accurate detection and classification of life-threatening ventricular arrhythmia episodes such as ventricular fibrillation (VF) and rapid ventricular tachycardia (VT) from electrocardiogram (ECG) is a challenging problem for patient monitoring and defibrillation therapy. This paper introduces a novel method for detection and classification of life-threatening ventricular arrhythmia episodes. The ECG signal is decomposed into various oscillatory modes using digital Taylor-Fourier transform (DTFT). The magnitude feature and a novel phase feature namely the phase difference (PD) are evaluated from the mode Taylor-Fourier coefficients of ECG signal. The least square support vector machine (LS-SVM) classifier with linear and radial basis function (RBF) kernels is employed for detection and classification of VT vs. VF, non-shock vs. shock and VF vs. non-VF arrhythmia episodes. The accuracy, sensitivity, and specificity values obtained using the proposed method are 89.81, 86.38, and 93.97%, respectively for the classification of Non-VF and VF episodes. Comparison with the performance of the state-of-the-art features demonstrate the advantages of the proposition.

Turnerellina, a new name for Turnerella Taylor & McKinney, 2006 (Bryozoa, Cheilostomata)

NARCIS (Netherlands)

Taylor, P.D.; McKinney, F.K.

2007-01-01

Turnerella Taylor & McKinney, 2006, p. 164, introduced for a new genus of cribrimorph Cheilostomata (Bryozoa), is preoccupied by Turnerella Cockerell, 1910, a genus of Hymenoptera, and two other introductions of the same name for new insect genera. We propose Turnerellina as a new name to replace

Torque scaling in small-gap Taylor-Couette flow with smooth or grooved wall

Science.gov (United States)

Zhu, Bihai; Ji, Zengqi; Lou, Zhengkun; Qian, Pengcheng

2018-03-01

The torque in the Taylor-Couette flow for radius ratios η ≥0.97 , with smooth or grooved wall static outer cylinders, is studied experimentally, with the Reynolds number of the inner cylinder reaching up to Rei=2 ×105 , corresponding to the Taylor number up to Ta =5 ×1010 . The grooves are perpendicular to the mean flow, and similar to the structure of a submersible motor stator. It is found that the dimensionless torque G , at a given Rei and η , is significantly greater for grooved cases than smooth cases. We compare our experimental torques for the smooth cases to the fit proposed by Wendt [F. Wendt, Ing.-Arch. 4, 577 (1993), 10.1007/BF02084936] and the fit proposed by Bilgen and Boulos [E. Bilgen and R. Boulos, J Fluids Eng. 95, 122 (1973), 10.1115/1.3446944], which shows both fits are outside their range for small gaps. Furthermore, an additional dimensionless torque (angular velocity flux) N uω in the smooth cases exhibits an effective scaling of N uω˜T a0.39 in the ultimate regime, which occurs at a lower Taylor number, Ta ≈3.5 ×107 , than the well-explored η =0.714 case (at Ta ≈3 ×108 ). The same effective scaling exponent, 0.39, is also evident in the grooved cases, but for η =0.97 and 0.985, there is a peak before this exponent appears.

Validation Study of Unnotched Charpy and Taylor-Anvil Impact Experiments using Kayenta

Energy Technology Data Exchange (ETDEWEB)

Kamojjala, Krishna [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lacy, Jeffrey [Idaho National Lab. (INL), Idaho Falls, ID (United States); Chu, Henry S. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Brannon, Rebecca [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2015-03-01

Validation of a single computational model with multiple available strain-to-failure fracture theories is presented through experimental tests and numerical simulations of the standardized unnotched Charpy and Taylor-anvil impact tests, both run using the same material model (Kayenta). Unnotched Charpy tests are performed on rolled homogeneous armor steel. The fracture patterns using Kayenta’s various failure options that include aleatory uncertainty and scale effects are compared against the experiments. Other quantities of interest include the average value of the absorbed energy and bend angle of the specimen. Taylor-anvil impact tests are performed on Ti6Al4V titanium alloy. The impact speeds of the specimen are 321 m/s and 393 m/s. The goal of the numerical work is to reproduce the damage patterns observed in the laboratory. For the numerical study, the Johnson-Cook failure model is used as the ductile fracture criterion, and aleatory uncertainty is applied to rate-dependence parameters to explore its effect on the fracture patterns.

Civil-Military Relations and Gen. Maxwell Taylor: Getting It Right and Getting It Wrong

National Research Council Canada - National Science Library

Tart, Randal

1997-01-01

... are paid. In the first situation, Taylor got his civil-military relations right, even though he fought a losing battle with President Eisenhower over Ike's dangerous defense strategy of 'massive retaliation...

A CFD analysis of flow blockage phenomena in ALFRED LFR demo fuel assembly

Energy Technology Data Exchange (ETDEWEB)

Di Piazza, Ivan, E-mail: ivan.dipiazza@enea.it [Italian National Agency for New Technologies, Energy and Sustainable Economic Development, C.R. ENEA Brasimone (Italy); Magugliani, Fabrizio [Ansaldo Nucleare, ANN, Corso Perrone n.25, Genova (Italy); Tarantino, Mariano [Italian National Agency for New Technologies, Energy and Sustainable Economic Development, C.R. ENEA Brasimone (Italy); Alemberti, Alessandro [Ansaldo Nucleare, ANN, Corso Perrone n.25, Genova (Italy)

2014-09-15

Highlights: • URANS simulations were performed on internal flow blockage in HLM fuel assemblies. • Comparison with RELAP results for foot blockage shows a very good agreement. • The temperature peak behind the blockage is dominant for large blockages. • A blockage of ∼15% leads to a maximum clad temperature around 800 °C in 3–4 s. • Local clad temperatures around 1000 °C are reached for blockages of 30% or more. - Abstract: A CFD study was carried out on fluid flow and heat transfer in the Lead-cooled Fuel Pin Bundle of the ALFRED LFR DEMO. In the context of GEN-IV heavy liquid metal-cooled reactors safety studies, the flow blockage in a fuel sub-assembly is considered one of the main issues to be addressed and the most important and realistic accident for LFR fuel assembly. The present paper is a first step toward a detailed analysis of such phenomena, and a CFD model and approach are presented to have a detailed thermo-fluid dynamic picture in the case of blockage. In particular the closed hexagonal, grid-spaced fuel assembly of the LFR ALFRED was modeled and computed. At this stage, the details of the spacer grids were not included, but a conservative analysis has been carried out based on the current main geometrical and physical features. Reactivity feedback, as well as axial power profile, were not included in this analysis. Results indicate that critical conditions, with clad temperatures around ∼900 °C, are reached with blockage larger than 30% in terms of area fraction. Two main effects can be distinguished: a local effect in the wake/recirculation region downstream the blockage and a global effect due to the lower mass flow rate in the blocked subchannels; the former effect gives rise to a temperature peak behind the blockage and it is dominant for large blockages (>20%), while the latter effect determines a temperature peak at the end of the active region and it is dominant for small blockages (<10%). The blockage area was placed at

Firm-specific investment, sticky prices and the Taylor principle

OpenAIRE

Sveen, Tommy; Weinke, Lutz

2005-01-01

According to the Taylor principle a central bank should adjust the nominal interest rate by more than one-for-one in response to changes in current inflation. Most of the existing literature supports the view that by following this simple recommendation a central bank can avoid being a source of unnecessary fluctuations in economic activity. The present paper shows that this conclusion is not robust with respect to the modelling of capital accumulation. We use our insights to discuss the desi...

The Ekman-Hartmann layer in MHD Taylor-Couette flow

OpenAIRE

Szklarski, Jacek; Rüdiger, Günther

2007-01-01

We study magnetic effects induced by rigidly rotating plates enclosing a cylindrical MHD Taylor-Couette flow at the finite aspect ratio $H/D=10$. The fluid confined between the cylinders is assumed to be liquid metal characterized by small magnetic Prandtl number, the cylinders are perfectly conducting, an axial magnetic field is imposed $\\Ha \\approx 10$, the rotation rates correspond to $\\Rey$ of order $10^2-10^3$. We show that the end-plates introduce, besides the well known Ekman circulati...

Arbuscular mycorrhizal fungi enhance both absorption and stabilization of Cd by Alfred stonecrop (Sedum alfredii Hance) and perennial ryegrass (Lolium perenne L.) in a Cd-contaminated acidic soil.

Science.gov (United States)

Hu, Junli; Wu, Shengchun; Wu, Fuyong; Leung, Ho Man; Lin, Xiangui; Wong, Ming Hung

2013-10-01

A greenhouse pot experiment was conducted to compare the phytoextraction efficiencies of Cd by hyper-accumulating Alfred stonecrop (Sedum alfredii Hance) and fast-growing perennial ryegrass (Lolium perenne L.) from a Cd-contaminated (1.6 mg kg(-1)) acidic soil, and their responses to the inoculations of two arbuscular mycorrhizal (AM) fungal strains, Glomus caledonium 90036 (Gc) and Glomus mosseae M47V (Gm). Ryegrass and stonecrop were harvested after growing for 9 and 27 wk, respectively. Without AM fungal inoculation, the weekly Cd extraction by stonecrop (8.0 μg pot(-1)) was 4.3 times higher than that by ryegrass (1.5 μg pot(-1)). Both Gc and Gm significantly increased (P soil acid phosphatase activities, and available P concentrations, and thereby plant P absorptions (except for Gm-inoculated ryegrass), shoot biomasses, and Cd absorptions (except for Gm-inoculated stonecrop), while only Gc-inoculated stonecrop significantly accelerated (P soil pH. The results suggested the potential application of hyper-accumulating Alfred stonecrop associated with AM fungi (notably Gc) for both extraction and stabilization of Cd in the in situ treatment of Cd-contaminated acidic soil. Copyright © 2013 Elsevier Ltd. All rights reserved.

Taylor-Couette flow stability with toroidal magnetic field

International Nuclear Information System (INIS)

Shalybkov, D

2005-01-01

The linear stability of the dissipative Taylor-Couette flow with imposed azimuthal magnetic field is considered. Unlike to ideal flow, the magnetic field is fixed function of radius with two parameters only: a ratio of inner to outer cylinder radii and a ratio of the magnetic field values on outer and inner cylinders. The magnetic field with boundary values ratio greater than zero and smaller than inverse radii ratio always stabilizes the flow and called stable magnetic field below. The current free magnetic field is the stable magnetic field. The unstable magnetic field destabilizes every flow if the magnetic field (or Hartmann number) exceeds some critical value. This instability survives even without rotation (for zero Reynolds number). For the stable without the magnetic field flow, the unstable modes are located into some interval of the vertical wave numbers. The interval length is zero for critical Hartmann number and increases with increasing Hartmann number. The critical Hartmann numbers and the length of the unstable vertical wave numbers interval is the same for every rotation law. There are the critical Hartmann numbers for m = 0 sausage and m = 1 kink modes only. The critical Hartmann numbers are smaller for kink mode and this mode is the most unstable mode like to the pinch instability case. The flow stability do not depend on the magnetic Prandtl number for m = 0 mode. The same is true for critical Hartmann numbers for m = 0 and m = 1 modes. The typical value of the magnetic field destabilizing the liquid metal Taylor-Couette flow is order of 100 Gauss

Alfred Walter Campbell and the visual functions of the occipital cortex.

Science.gov (United States)

Macmillan, Malcolm

2014-07-01

In his pioneering cytoarchitectonic studies of the human brain, Alfred Walter Campbell identified two structurally different areas in the occipital lobes and assigned two different kinds of visual functions to them. The first area, the visuosensory, was essentially on the mesial surface of the calcarine fissure. It was the terminus of nervous impulses generated in the retina and was where simple visual sensations arose. The second area, the visuopsychic, which surrounded or invested the first, was where sensations were interpreted and elaborated into visual perceptions. I argue that Campbell's distinction between the two areas was the starting point for the eventual differentiation of areas V1-V5. After a brief outline of Campbell's early life and education in Australia and of his Scottish medical education and early work as a pathologist at the Lancashire County Lunatic Asylum at Rainhill near Liverpool, I summarise his work on the human brain. In describing the structures he identified in the occipital lobes, I analyse the similarities and differences between them and the related structures identified by Joseph Shaw Bolton. I conclude by proposing some reasons for how that work came to be overshadowed by the later studies of Brodmann and for the more general lack of recognition given Campbell and his work. Those reasons include the effect of the controversies precipitated by Campbell's alliance with Charles Sherrington over the functions of the sensory and motor cortices. Copyright © 2012 Elsevier Ltd. All rights reserved.

Mode coupling in nonlinear Rayleigh--Taylor instability

International Nuclear Information System (INIS)

Ofer, D.; Shvarts, D.; Zinamon, Z.; Orszag, S.A.

1992-01-01

This paper studies the interaction of a small number of modes in the two-fluid Rayleigh--Taylor instability at relatively late stages of development, i.e., the nonlinear regime, using a two-dimensional hydrodynamic code incorporating a front-tracking scheme. It is found that the interaction of modes can greatly affect the amount of mixing and may even reduce the width of the mixing region. This interaction is both relatively long range in wave-number space and also acts in both directions, i.e., short wavelengths affect long wavelengths and vice versa. Three distinct stages of interaction have been identified, including substantial interaction among modes some of which may still be in their classical (single mode) ''linear'' phase

Rayleigh-Taylor-instability evolution in colliding-plasma-jet experiments with magnetic and viscous stabilization

Energy Technology Data Exchange (ETDEWEB)

Adams, Colin Stuart [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Univ. of New Mexico, Albuquerque, NM (United States); Univ. of Washington, Seattle, WA (United States)

2015-01-15

The Rayleigh-Taylor instability causes mixing in plasmas throughout the universe, from micron-scale plasmas in inertial confinement fusion implosions to parsec-scale supernova remnants. The evolution of this interchange instability in a plasma is influenced by the presence of viscosity and magnetic fields, both of which have the potential to stabilize short-wavelength modes. Very few experimental observations of Rayleigh-Taylor growth in plasmas with stabilizing mechanisms are reported in the literature, and those that are reported are in sub-millimeter scale plasmas that are difficult to diagnose. Experimental observations in well-characterized plasmas are important for validation of computational models used to make design predictions for inertial confinement fusion efforts. This dissertation presents observations of instability growth during the interaction between a high Mach-number, initially un-magnetized plasma jet and a stagnated, magnetized plasma. A multi-frame fast camera captures Rayleigh-Taylor-instability growth while interferometry, spectroscopy, photodiode, and magnetic probe diagnostics are employed to estimate plasma parameters in the vicinity of the collision. As the instability grows, an evolution to longer mode wavelength is observed. Comparisons of experimental data with idealized magnetohydrodynamic simulations including a physical viscosity model suggest that the observed instability evolution is consistent with both magnetic and viscous stabilization. These data provide the opportunity to benchmark computational models used in astrophysics and fusion research.

Experiment of ablative Rayleigh-Taylor instability in a strongly non linear regime on the National Ignition Facility

International Nuclear Information System (INIS)

Casner, A.; Masse, L.; Liberatore, S.; Delorme, B.; Jacquet, L.; Loiseau, P.; Smalyuk, V. A.; Martinez, D.; Remington, B. A.

2012-01-01

As the control of the development of Rayleigh-Taylor-type hydrodynamic instabilities is crucial to achieve efficient implosions on the Laser Megajoule, and as the complexity of these instabilities requires an experimental validation of theoretical models and of the associated numerical simulations, the authors briefly present a proposition of experiments aimed at studying the strongly non linear Rayleigh-Taylor instability on the National Ignition Facility (NIF). This should allow a regime of competition between bubbles to be achieved for the first time in direct attack. They evoke the first experiment performed in March 2013

Reflexión sobre la revisoría fiscal desde la sociología fenomenológica de Alfred Schütz

OpenAIRE

Cuenú Cabezas, Jairo Emiro

2014-01-01

El presente artículo pretende realizar una reflexión sobre la revisoría fiscal, tomando como referencia la teoría socio-fenomenológica del austríaco Alfred Schütz; la cual analiza, entre otras categorías, las relaciones de alteridad en el mundo de la vida cotidiana; mundo que caracteriza como la realidad primaria o fundamental, porque en ésta se da la comunicación, la acción y la intersubjetividad. La intersubjetividad es abordada a partir de la matriz espacio-tiempo, la cual determina que cu...

Equation of state at finite net-baryon density using Taylor coefficients up to sixth order

International Nuclear Information System (INIS)

Huovinen, Pasi; Petreczky, Péter; Schmidt, Christian

2014-01-01

We employ the lattice QCD data on Taylor expansion coefficients up to sixth order to construct an equation of state at finite net-baryon density. When we take into account how hadron masses depend on lattice spacing and quark mass, the coefficients evaluated using the p4 action are equal to those of hadron resonance gas at low temperature. Thus the parametrised equation of state can be smoothly connected to the hadron resonance gas equation of state. We see that the equation of state using Taylor coefficients up to second order is realistic only at low densities, and that at densities corresponding to s/n B ≳40, the expansion converges by the sixth order term

Self-consistent model of the Rayleigh--Taylor instability in ablatively accelerated laser plasma

International Nuclear Information System (INIS)

Bychkov, V.V.; Golberg, S.M.; Liberman, M.A.

1994-01-01

A self-consistent approach to the problem of the growth rate of the Rayleigh--Taylor instability in laser accelerated targets is developed. The analytical solution of the problem is obtained by solving the complete system of the hydrodynamical equations which include both thermal conductivity and energy release due to absorption of the laser light. The developed theory provides a rigorous justification for the supplementary boundary condition in the limiting case of the discontinuity model. An analysis of the suppression of the Rayleigh--Taylor instability by the ablation flow is done and it is found that there is a good agreement between the obtained solution and the approximate formula σ = 0.9√gk - 3u 1 k, where g is the acceleration, u 1 is the ablation velocity. This paper discusses different regimes of the ablative stabilization and compares them with previous analytical and numerical works

Chebyshev-Taylor Parameterization of Stable/Unstable Manifolds for Periodic Orbits: Implementation and Applications

Science.gov (United States)

Mireles James, J. D.; Murray, Maxime

2017-12-01

This paper develops a Chebyshev-Taylor spectral method for studying stable/unstable manifolds attached to periodic solutions of differential equations. The work exploits the parameterization method — a general functional analytic framework for studying invariant manifolds. Useful features of the parameterization method include the fact that it can follow folds in the embedding, recovers the dynamics on the manifold through a simple conjugacy, and admits a natural notion of a posteriori error analysis. Our approach begins by deriving a recursive system of linear differential equations describing the Taylor coefficients of the invariant manifold. We represent periodic solutions of these equations as solutions of coupled systems of boundary value problems. We discuss the implementation and performance of the method for the Lorenz system, and for the planar circular restricted three- and four-body problems. We also illustrate the use of the method as a tool for computing cycle-to-cycle connecting orbits.

Numerical simulation of Rayleigh-Taylor instability in ablation driven systems

International Nuclear Information System (INIS)

Verdon, C.P.

1984-01-01

Two-dimensional numerical simulations of ablatively accelerated thin shells subject to Rayleigh-Taylor instability are presented. Results for both single wavelength and multiwavelength perturbations show that the nonlinear effects of the instability are evident mainly in the bubble rather than the spike. Approximate roles for predicting the dominant nonlinear mode-mode interactions, which limit shell performance, are also discussed. The work concludes with a discussion of recommendations for future work in this area

FLANDES, Flange Design for He Circuits by Taylor-Forge Method

International Nuclear Information System (INIS)

Pitchford, B.E.

1977-01-01

1 - Nature of the physical problem solved: Flange design for helium circuits. 2 - Method of solution: This is a flange design programme based on the Taylor forge method with an additional calculation of flange rotation and bolt load change during the application of internal pressure. The method relates only to the integral hub type of flange, with or without a secondary O-ring seal but will deal also with the flange and cover plate case

The World of Barilla Taylor: Bringing History to Life through Primary Sources.

Science.gov (United States)

Stearns, Liza

1997-01-01

Presents a lesson plan using material from a primary source-based curriculum kit titled "The World of Barilla Taylor." The kit uses personal letters, maps, hospital and work records, and other primary sources to document the life of a young woman working in the textile mills in 19th-century Massachusetts. (MJP)

Effect on Non-Newtonian Rheology on Mixing in Taylor-Couette Flow

Science.gov (United States)

Cagney, Neil; Balabani, Stavroula

2017-11-01

Mixing processes within many industry applications are strongly affected by the rheology of the working fluid. This is particularly relevant for pharmaceutical, food and waste treatment industries, where the working fluids are often strongly non-Newtonian, and significant variations in rheology between batches may occur. We approach the question of how rheology affects mixing by focussing on a the classical case of Taylor-Couette flow, which exhibits a number of instabilities and flow regimes as a function of Reynolds number. We examine Taylor-Couette flow generated for a range of aqueous solutions of xantham gum or corn starch, such that the rheology varies from shear-thinning to shear-thickening. For each case, we measure the power consumption using a torque meter and the flow field using high speed, time-resolved Particle-Image Velocimetry. The mixing characteristics are quantified using a number of Lagrangian and Eulerian approaches, including the coarse grained density method and vortex strength. By comparing these metrics to the power number, we discuss how the mixing efficiency (ratio of mixing effectiveness to power input) varies with the flow index of the fluid.

The Taylor-expansion method of moments for the particle system with bimodal distribution

Directory of Open Access Journals (Sweden)

Liu Yan-Hua

2013-01-01

Full Text Available This paper derives the multipoint Taylor expansion method of moments for the bimodal particle system. The collision effects are modeled by the internal and external coagulation terms. Simple theory and numerical tests are performed to prove the effect of the current model.

T. S. Eliot’s ‘Obscurity’ in The Love Song of J. Alfred Prufrock

Directory of Open Access Journals (Sweden)

Longxing Wei

2016-07-01

Full Text Available T. S. Eliot's earliest verse is composed of observations, detached, ironic, and alternatively disillusioned and nostalgic in tone. Eliot's mingling of subtle observation with unexpected cliché represents a difficulty that is often magnified because too much 'obscurity' is assumed. This paper aims at clarifying the 'obscurity' by means of a stylistic analysis of the linguistic devices that the poet used to create "The Love Song of J. Alfred Prufrock" and its intended meaning. Adopting the concept of style as 'foregrounding', the idea that style is constituted by departures from linguistic norms, it analyzes the poem in terms of its lexical foregrounding, and adopting the concept of style as 'choice', the idea that style is constituted by choices of linguistic devices, it analyzes the poem in terms of its syntactic choices. It claims that it is the systematic foregrounding or violation of the norm of the standard which makes possible the poetic utilization of language. Without seeing foregrounding as a poet's linguistic device, there could be no poetry for the poet or no possible understanding of poems for the reader. It also claims that stylistically significant syntactic choices by the poet serve effectively the intended meaning.

Alfred Schütz: do referencial teórico-filosófico aos princípios metodológicos de pesquisa fenomenológica

OpenAIRE

Zeferino,Maria Terezinha; Carraro,Telma Elisa

2013-01-01

Se trata de una reflexión sobre el referencial teórico-filosófico de la sociología fenomenológica, presentando los principios metodológicos de la investigación de Alfred Schütz, entendiendo que este referencial permite la composición completa de la investigación fenomenológica. Cada principio es presentado detalladamente usando la investigación que condujo a la propuesta como referencia, ejemplificando la forma en que fueron trabajadas las etapas para lograr una actitud fenomenológica. Se per...

Statistical approach of weakly nonlinear ablative Rayleigh-Taylor instability

International Nuclear Information System (INIS)

Garnier, J.; Masse, L.

2005-01-01

A weakly nonlinear model is proposed for the Rayleigh-Taylor instability in presence of ablation and thermal transport. The nonlinear effects for a single-mode disturbance are computed, included the nonlinear correction to the exponential growth of the fundamental modulation. Mode coupling in the spectrum of a multimode disturbance is thoroughly analyzed by a statistical approach. The exponential growth of the linear regime is shown to be reduced by the nonlinear mode coupling. The saturation amplitude is around 0.1λ for long wavelengths, but higher for short instable wavelengths in the ablative regime

Comments on the Huang and Taylor model of ion-implanted silicon-gate depletion-mode IGFET

International Nuclear Information System (INIS)

Marciniak, W.; Madura, H.

1985-01-01

Recently the Huang and Taylor model (HT model) of built-in channel MOS transistors has been widely used in the analysis of electronic circuits because of its relative simplicity. Huang and Taylor assumed that the effects of the finite channel thickness may be represented by an average semiconductor capacitance in series with the gate oxide capacitance. The derivation of the current-voltage characteristics is based on a linear equation of surface depleted charge density Qsub(s), which is calculated as the sheet charge of constant capacitance C-bar. This is done instead of using the exact solution of the Poisson equation, which has a rather complex form of nonlinear relationship between the charge Qsub(s) and the gate voltage. The basic equation is given. (author)

Taylor expansion of luminosity distance in Szekeres cosmological models: effects of local structures evolution on cosmographic parameters

Energy Technology Data Exchange (ETDEWEB)

Villani, Mattia, E-mail: villani@fi.infn.it [Sezione INFN di Firenze, Polo Scientifico Via Sansone 1, 50019, Sesto Fiorentino (Italy)

2014-06-01

We consider the Goode-Wainwright representation of the Szekeres cosmological models and calculate the Taylor expansion of the luminosity distance in order to study the effects of the inhomogeneities on cosmographic parameters. Without making a particular choice for the arbitrary functions defining the metric, we Taylor expand up to the second order in redshift for Family I and up to the third order for Family II Szekeres metrics under the hypotesis, based on observation, that local structure formation is over. In a conservative fashion, we also allow for the existence of a non null cosmological constant.

Taylor impact of glass rods

International Nuclear Information System (INIS)

Willmott, G.R.; Radford, D.D.

2005-01-01

The deformation and fracture behavior of soda-lime and borosilicate glass rods was examined during classic and symmetric Taylor impact experiments for impact pressures to 4 and 10 GPa, respectively. High-speed photography and piezoresistive gauges were used to measure the failure front velocities in both glasses, and for impact pressures below ∼2 GPa the failure front velocity increases rapidly with increasing pressure. As the pressure was increased above ∼3 GPa, the failure front velocities asymptotically approached maximum values between the longitudinal and shear wave velocities of each material; at ∼4 GPa, the average failure front velocities were 4.7±0.5 and 4.6±0.5 mm μs -1 for the soda-lime and borosilicate specimens, respectively. The observed mechanism of failure in these experiments involved continuous pressure-dependent nucleation and growth of microcracks behind the incident wave. As the impact pressure was increased, there was a decrease in the time to failure. The density of cracks within the failed region was material dependent, with the more open-structured borosilicate glass showing a larger fracture density

Breakup of an accelerated shell owing to Rayleigh--Taylor instability

International Nuclear Information System (INIS)

Suydam, B.R.

1978-06-01

A simplified model for the Rayleigh-Taylor instability of an accelerated shell is examined, and it is found that the most dangerous wavelength to be about that of the shell thickness. The shell material is assumed to be an inviscid, incompressible fluid. Effects of finite compressibility and of surface tension are found to be negligible, but the effects of viscosity are shown to be very large. The need for better knowledge of viscosity at high pressure is pointed out

The Taylor-Proudman column in a rapidly-rotating compressible fluid I. energy transports

International Nuclear Information System (INIS)

Park, Jun Sang

2014-01-01

A theoretical study is made of the steady flow of a compressible fluid in a rapidly rotating finite cylinder. Flow is generated by imposing mechanical and/or thermal disturbances at the rotating endwall disks. Both the Ekman and Rossby numbers are small. An examination is made of the energy budget for a control volume in the Ekman boundary layer. A combination of physical variables, which is termed the energy flux content, consisting of temperature and modified angular momentum, emerges to be relevant. The distinguishing features of a compressible fluid, in contrast to those of an incompressible fluid, are noted. A plausible argument is given to explain the difficulty in achieving the Taylor-Proudman column in a compressible rotating fluid. For the Taylor-Proudman column to be sustained, in the interior, it is shown that the net energy transport between the solid disk wall and the interior fluid should vanish. Physical rationalizations are facilitated by resorting to the concept of the afore-stated energy flux content.

Taylor dispersion in wind-driven current

Science.gov (United States)

Li, Gang; Wang, Ping; Jiang, Wei-Quan; Zeng, Li; Li, Zhi; Chen, G. Q.

2017-12-01

Taylor dispersion associated with wind-driven currents in channels, shallow lakes and estuaries is essential to hydrological environmental management. For solute dispersion in a wind-driven current, presented in this paper is an analytical study of the evolution of concentration distribution. The concentration moments are intensively derived for an accurate presentation of the mean concentration distribution, up to the effect of kurtosis. The vertical divergence of concentration is then deduced by Gill's method of series expansion up to the fourth order. Based on the temporal evolution of the vertical concentration distribution, the dispersion process in the wind-driven current is concretely characterized. The uniform shear leads to a special symmetrical distribution of mean concentration free of skewness. The non-uniformity of vertical concentration is caused by convection and smeared out gradually by the effect of diffusion, but fails to disappear even at large times.

Determination of the diffusion coefficient of salts in non-Newtonian liquids by the Taylor dispersion method

Energy Technology Data Exchange (ETDEWEB)

Mey, Paula; Varges, Priscilla R.; Mendes, Paulo R. de Souza [Dept. of Mechanical Engineering. Pontificia Universidade Catolica do RJ (PUC-Rio), RJ (Brazil)], e-mails: prvarges@puc-rio.br, pmendes@puc-rio.br

2010-07-01

This research looked for a method to determine the binary diffusion coefficient D of salts in liquids (especially in drilling fluids) not only accurately, but in a reasonable time. We chose to use the Taylor Dispersion Method. This technique has been used for measuring binary diffusion coefficients in gaseous, liquid and supercritical fluids, due to its simplicity and accuracy. In the method, the diffusion coefficient is determined by the analysis of the dispersion of a pulse of soluble material in a solvent flowing laminarly through a tube. This work describes the theoretical basis and the experimental requirements for the application of the Taylor Dispersion Method, emphasizing the description of our experiment. A mathematical formulation for both Newtonian and non-Newtonian fluids is presented. The relevant sources of errors are discussed. The experimental procedure and associated analysis are validated by applying the method in well known systems, such as NaCl in water.D of salts in liquids (especially in drilling fluids) not only accurately, but in a reasonable time. We chose to use the Taylor Dispersion Method. This technique has been used for measuring binary diffusion coefficients in gaseous, liquid and supercritical fluids, due to its simplicity and accuracy. In the method, the diffusion coefficient is determined by the analysis of the dispersion of a pulse of soluble material in a solvent flowing laminarly through a tube. This work describes the theoretical basis and the experimental requirements for the application of the Taylor Dispersion Method, emphasizing the description of our experiment. A mathematical formulation for both Newtonian and non-Newtonian fluids is presented. The relevant sources of errors are discussed. The experimental procedure and associated analysis are validated by applying the method in well known systems, such as NaCl in water. (author)

Nonlinear theory of the collisional Rayleigh-Taylor instability in equatorial spread F

International Nuclear Information System (INIS)

Chaturvedi, P.K.; Ossakow, S.L.

1977-01-01

The nonlinear behavior of the collisional Rayleigh-Taylor instability is studied in equatorial Spread F by including a dominant two-dimensional nonlinearity. It is found that on account of this nonlinearity the instability saturates by generating damped higher spatial harmonics. The saturated power spectrum for the density fluctuations is discussed. A comparison between experimental observations and theory is presented

Interaction between ground water and surface water in Taylor Slough and vicinity, Everglades National Park, South Florida; study methods and appendixes

Science.gov (United States)

Harvey, Judson W.; Jackson, J.M.; Mooney, R.H.; Choi, Jungyill

2000-01-01

The data presented in this report are products of an investigation that quantified interactions between ground water and surface water in Taylor Slough in Everglades National Park. Determining the extent of hydrologic interactions between wetland surface water and ground water in Taylor Slough is important because the balance of freshwater flow in the lower part of the Slough is uncertain. Although freshwater flows through Taylor Slough are quite small in comparison to Shark Slough (the larger of the two major sloughs in Everglades National Park), flows through Taylor Slough are especially important to the ecology of estuarine mangrove embayments of northeastern Florida Bay. Also, wetland and ground- water interactions must be quantified if their role in affecting water quality is to be determined. In order to define basic hydrologic characteristics of the wetland, depth of wetland peat was mapped, and hydraulic conductivity and vertical hydraulic gradients in peat were determined. During specific time periods representing both wet and dry conditions in the area, the distribution of major ions, nutrients, and water stable isotopes throughout the slough were determined. The purpose of chemical measurements was to identify an environmental tracer could be used to quantify ground-water discharge.

Power Laws and Similarity of Rayleigh-Taylor and Richtmyer-Meshkov Mixing Fronts at All Density Ratios

International Nuclear Information System (INIS)

Alon, U.; Hecht, J.; Ofer, D.; Shvarts, D.

1995-01-01

The nonlinear evolution of large structure in Rayleigh-Taylor and Richtmyer-Meshkov bubble and spike fronts is studied numerically and explained theoretically on the basis of single-mode and two-bubble interaction physics at Atwood numbers (A). Multimode Rayleigh-Taylor bubble (spike) fronts are found as h B =α B Agt 2 [h s =α s (A)gt 2 ] with α B =0.05, while Richtmyer-Meshkov bubble (spike) fronts are found as h B =a B t θ B (h s =a s t θ s (A) ) with θ B =0.4 at all A's. The dependence of these scaling laws and parameters on A and on initial conditions is explained

Wall Shear Rate in the Taylor-Couette-Poiseuille Flow at Low Axial Reynolds Number

Czech Academy of Sciences Publication Activity Database

Dumont, E.; Fayolle, F.; Sobolík, Václav; Legrand, J.

2002-01-01

Roč. 45, č. 3 (2002), s. 679-689 ISSN 0017-9310 Institutional research plan: CEZ:AV0Z4072921 Keywords : Taylor vortices * electrodiffusion diagnostics * model fluid s Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.268, year: 2002

An optimized formulation for Deprit-type Lie transformations of Taylor maps for symplectic systems

International Nuclear Information System (INIS)

Shi, Jicong

1993-01-01

An optimized iterative formulation is presented for directly transforming a Taylor map of a symplectic system into a Deprit-type Lie transformation, which is a composition of a linear transfer matrix and a single Lie transformation, to an arbitrary order

The Rayleigh-Taylor instability under electrical pulse discharge in water

International Nuclear Information System (INIS)

Kononov, A.V.; Porytskyy, P.V.; Starchyk, P.D.; Voitenko, L.M.

1999-01-01

The development of the Rayleigh-Taylor instability is studied on the interface between both the plasma channel and liquid medium under an electrical pulse discharge in water.It is shown that,growth of the irregularities of the contact interface leads to the increasing of heat flux from the discharge channel due to the growth of an interfacial area and the incoming of water matter into a discharge channel.As a result of these processes the characteristics of the discharge may be strongly varied

Theory of current instability experiments in magnetic Taylor-Couette flows

OpenAIRE

Ruediger, G.; Schultz, M.; Shalybkov, D.; Hollerbach, R.

2006-01-01

We consider the linear stability of dissipative MHD Taylor-Couette flow with imposed toroidal magnetic fields. The inner and outer cylinders can be either insulating or conducting; the inner one rotates, the outer one is stationary. The magnetic Prandtl number can be as small as 10-5, approaching realistic liquid-metal values. The magnetic field destabilizes the flow, except for radial profiles of B$_\\phi$(R) close to the current-free solution. The profile with B$_{in}$=B$_{out}$ (the most un...

Some investigations on the mean and fluctuating velocities of an oscillating Taylor bubble

International Nuclear Information System (INIS)

Madani, Sara; Caballina, Ophelie; Souhar, Mohamed

2012-01-01

Highlights: ► The unsteady motion of an oscillating Taylor bubble has been studied. ► A non-dimensionalized velocity differential equation is numerically solved. ► The role of dimensionless numbers on the dynamics of the bubble is highlighted. ► Mean and fluctuating velocities and the phase shift are experimentally investigated. ► Correlations allowing the prediction of these latter parameters are proposed. - Abstract: The slug flow characterized by large elongated bubbles also called Taylor bubbles is widely encountered in nuclear reactor steam generators, cooling plants, reboilers, etc. The analysis of slug flow is very important as the instability caused by such flows can affect the safety features of nuclear reactors and other two-phase flow equipments. In this paper, we study the motion of a Taylor bubble rising in stagnant fluids in a vertical oscillating pipe. The investigation is restricted to high Reynolds numbers and to an intermediate range of Bond numbers where the effects of surface tension can be considered. The Froude number ranged between 0.22 and 0.33. Firstly, detailed analysis of models proposed in the literature for the motion of a Taylor bubble in an unsteady acceleration field is realized. The velocity differential equation obtained in the case of potential and axisymmetric flow without surface tension given in the literature is first non-dimensionalized to highlight dimensionless numbers. Then, the instantaneous velocity of the bubble is numerically determined. Mean and fluctuating velocities as well as the phase shift (U ¯ b , U f and φ) are estimated by using a technique based on the nonlinear least squares method. Results enable a discussion on the role played by dimensionless numbers on the dynamics of the bubble. It is found that the two parameters, the relative acceleration and the Bond number (a and Bo) have a governing role on the evolution of mean and fluctuating velocities while the ratio of the oscillation amplitude to

Reverse Taylor Tests on Ultrafine Grained Copper

International Nuclear Information System (INIS)

Mishra, A.; Meyers, M. A.; Martin, M.; Thadhani, N. N.; Gregori, F.; Asaro, R. J.

2006-01-01

Reverse Taylor impact tests have been carried out on ultrafine grained copper processed by Equal Channel Angular Pressing (ECAP). Tests were conducted on an as-received OFHC Cu rod and specimens that had undergone sequential ECAP passes (2 and 8). The average grain size ranged from 30 μm for the initial sample to less than 0.5 μm for the 8-pass samples. The dynamic deformation states of the samples, captured by high speed digital photography were compared with computer simulations run in AUTODYN-2D using the Johnson-Cook constitutive equation with constants obtained from stress-strain data and by fitting to an experimentally measured free surface velocity trace. The constitutive response of copper of varying grain sizes was obtained through quasistatic and dynamic mechanical tests and incorporation into constitutive models

Cylindrical Taylor states conserving total absolute magnetic helicity

Science.gov (United States)

Low, B. C.; Fang, F.

2014-09-01

The Taylor state of a three-dimensional (3D) magnetic field in an upright cylindrical domain V is derived from first principles as an extremum of the total magnetic energy subject to a conserved, total absolute helicity Habs. This new helicity [Low, Phys. Plasmas 18, 052901 (2011)] is distinct from the well known classical total helicity and relative total helicity in common use to describe wholly-contained and anchored fields, respectively. A given field B, tangential along the cylindrical side of V, may be represented as a unique linear superposition of two flux systems, an axially extended system along V and a strictly transverse system carrying information on field-circulation. This specialized Chandrasekhar-Kendall representation defines Habs and permits a neat formulation of the boundary-value problem (BVP) for the Taylor state as a constant-α force-free field, treating 3D wholly-contained and anchored fields on the same conceptual basis. In this formulation, the governing equation is a scalar integro-partial differential equation (PDE). A family of series solutions for an anchored field is presented as an illustration of this class of BVPs. Past treatments of the constant-α field in 3D cylindrical geometry are based on a scalar Helmholtz PDE as the governing equation, with issues of inconsistency in the published field solutions discussed over time in the journal literature. The constant-α force-free equation reduces to a scalar Helmholtz PDE only as special cases of the 3D integro-PDE derived here. In contrast, the constant-α force-free equation and the scalar Helmholtz PDE are absolutely equivalent in the spherical domain as discussed in Appendix. This theoretical study is motivated by the investigation of the Sun's corona but the results are also relevant to laboratory plasmas.

Unstable Titan-generated Rayleigh-Taylor Lakes Impact Ice

Science.gov (United States)

Umurhan, O. M.; Korycansky, D. G.; Zahnle, K. J.

2014-12-01

The evolution of surface morphology on Titan, Triton, and other worlds is strongly influenced by the interplay of various fluid dynamical processes. Specifically, overturning instabilities can easily arise due to the special circumstances of landform evolution that probably occurred on these worlds. On Titan, large impacts that formed basins like Menrva crater (and possibly Hotei Regio) would have generated impact-melt ice lakes unstably arranged over less dense ice. Cantaloupe terrains, for example as seen on Triton, may be the result of condensation of volatiles (methane, nitrogen) leading to unstably stratified layers of different compositions and densities. In each of these cases, Rayleigh-Taylor instabilities leading to large scale diapirism may be at play. In addition to the dynamics of these instabilities, other physical effects (e.g. heat diffusion, freezing/melting, porosity, temperature dependent viscosity) likely play an important role in the evolution of these features. In this ongoing study, we examine the properties of unstably stratified fluids in which the lower less-dense ice has a temperature dependent viscosity. Surprisingly, we find that there exists an optimal disturbance length scale corresponding to the fastest growth of the Rayleigh-Taylor instability. For unstably stratified layers of water (low viscosity heavy liquid lying above an ice whose viscosity increases with depth) the fastest growing mode corresponds to 40-60 km scales with overturn times of approximately 100 days. We present a detailed numerical stability analysis in a corresponding Boussinessq model (in the creeping flow limit) incorporating thermal conduction and latent heat release and we examine the stability properties surveying a variety of parameters. We have also developed a two-dimensional numerical code (a hybrid spectral/compact-differencing scheme) to model the evolution of such systems for which we shall present preliminary numerical results depicting the outcome of

Hannah Arendt and Charles Taylor: For the Recovery of the Meaning of the World

Directory of Open Access Journals (Sweden)

Gabriel Guedes Rossatti

2017-12-01

Full Text Available Hannah Arendt and Charles Taylor are two of the philosophers who have most seriously tackled the problem of individualism in the contemporary world and, thus, my proposal is to approximate their respective theories. I shall argue, therefore, that both depart from the very same premise, i.e. the massive presence of individualism at the heart of the ideology of Modernity, as well that both propose fundamentally the same sets of solutions for this problem: 1 the need for a retrieval of republican principles in order to reanimate politics under the conditions of modernity and 2 this in order to recuperate the meaning of the world as something common to human beings. Thus, my proposal aims at the discussion of certain key-elements present in the theory of Taylor in order to throw light on the “communitarian” or dialogical aspects present in the theory of Arendt.

Theory of current-driven instability experiments in magnetic Taylor-Couette flows.

Science.gov (United States)

Rüdiger, Günther; Schultz, Manfred; Shalybkov, Dima; Hollerbach, Rainer

2007-11-01

We consider the linear stability of dissipative magnetic Taylor-Couette flow with imposed toroidal magnetic fields. The inner and outer cylinders can be either insulating or conducting; the inner one rotates, the outer one is stationary. The magnetic Prandtl number can be as small as 10(-5) , approaching realistic liquid-metal values. The magnetic field destabilizes the flow, except for radial profiles of B(phi)(R) close to the current-free solution. The profile with B(in)=B(out) (the most uniform field) is considered in detail. For weak fields the Taylor-Couette flow is stabilized, until for moderately strong fields the m=1 azimuthal mode dramatically destabilizes the flow again so that a maximum value for the critical Reynolds number exists. For sufficiently strong fields (as measured by the Hartmann number) the toroidal field is always unstable, even for the nonrotating case with Re=0 . The electric currents needed to generate the required toroidal fields in laboratory experiments are a few kA if liquid sodium is used, somewhat more if gallium is used. Weaker currents are needed for wider gaps, so a wide-gap apparatus could succeed even with gallium. The critical Reynolds numbers are only somewhat larger than the nonmagnetic values; hence such experiments would work with only modest rotation rates.

Manipulating Rayleigh-Taylor Growth Using Adjoints

Science.gov (United States)

Kord, Ali; Capecelatro, Jesse

2017-11-01

It has been observed that initial interfacial perturbations affect the growth of Rayleigh-Taylor (RT) instabilities. However, it remains to be seen to what extent the perturbations alter the RT growth rate. Direct numerical simulations (DNS) provide a powerful means for studying the effects of initial conditions (IC) on the growth rate. However, a brute-force approach for identifying optimal initial perturbations is not practical via DNS. In addition, identifying sensitivity of the RT growth to the large number of parameters used in defining the IC is computationally expensive. A discrete adjoint is formulated to measure sensitivities of multi-mode RT growth to ICs in a high-order finite difference framework. The sensitivity is used as a search direction for adjusting the initial perturbations to both maximize and suppress the RT growth rate during its non-linear regime. The modes that contribute the greatest sensitivity are identified, and optimized perturbation energy spectrum are reported. PhD Student, Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI.

Taylor-Lagrange regularization scheme and light-front dynamics

International Nuclear Information System (INIS)

Grange, P.; Mathiot, J.-F.; Mutet, B.; Werner, E.

2010-01-01

The recently proposed renormalization scheme based on the definition of field operators as operator valued distributions acting on specific test functions is shown to be very convenient in explicit calculations of physical observables within the framework of light-front dynamics. We first recall the main properties of this procedure based on identities relating the test functions to their Taylor remainder of any order expressed in terms of Lagrange's formulae, hence the name given to this scheme. We thus show how it naturally applies to the calculation of state vectors of physical systems in the covariant formulation of light-front dynamics. As an example, we consider the case of the Yukawa model in the simple two-body Fock state truncation.

A New NPGS Special Collection: Norman L. Taylor University of Kentucky Clover Collection

Science.gov (United States)

Dr. Norman L. Taylor was a world renowned Professor and clover breeder in the Department of Plant and Soil Sciences at the University of Kentucky for 48 years. Following retirement in 2001, he continued working on clovers up until his death in 2010. Dr. Taylor’s entire career was devoted to enhancin...

Observation of Magnetocoriolis Waves in a Liquid Metal Taylor-Couette Experiment

International Nuclear Information System (INIS)

Nornberg, M. D.; Ji, H.; Schartman, E.; Roach, A.; Goodman, J.

2010-01-01

The first observation of fast and slow magnetocoriolis (MC) waves in a laboratory experiment is reported. Rotating nonaxisymmetric modes arising from a magnetized turbulent Taylor-Couette flow of liquid metal are identified as the fast and slow MC waves by the dependence of the rotation frequency on the applied field strength. The observed slow MC wave is damped but the observation provides a means for predicting the onset of the magnetorotational instability.

Observation of magnetocoriolis waves in a liquid metal Taylor-Couette experiment.

Science.gov (United States)

Nornberg, M D; Ji, H; Schartman, E; Roach, A; Goodman, J

2010-02-19

The first observation of fast and slow magnetocoriolis (MC) waves in a laboratory experiment is reported. Rotating nonaxisymmetric modes arising from a magnetized turbulent Taylor-Couette flow of liquid metal are identified as the fast and slow MC waves by the dependence of the rotation frequency on the applied field strength. The observed slow MC wave is damped but the observation provides a means for predicting the onset of the magnetorotational instability.

Early East Asian art history in Vienna and its trajectories: Josef Strzygowski, Karl With, Alfred Salmony

Directory of Open Access Journals (Sweden)

Julia Orell

2015-12-01

Full Text Available In 1912 Josef Strzygowski founded the ‘Section for East Asian Art History’ at the University of Vienna, which attracted many students who would continue their careers in museums and at universities and thus established East Asian art history as an academic field. This paper examines these early art historical engagements with East Asian art: First, I discuss the role of East Asian art in Strzygowski’s agenda of broadening art history’s geographical scope beyond Europe and in his argument about the dominance of ‘Nordic’ artistic traditions in Europe and in Asia. Secondly, I introduce the work of two early students at the ‘Section for East Asian Art History’ in Vienna, Karl With and Alfred Salmony. Their respective approaches to East Asian art exemplify a range of methodological concerns of their time, from stylistic narratives, the concept of ars una, comparative frameworks, to ideas about cultural or national ‘purity’ in the arts, and an interest in cross-cultural adaption and transformation of motifs and symbolism.

Lattice QCD for Baryon Rich Matter – Beyond Taylor Expansions

Energy Technology Data Exchange (ETDEWEB)

Bornyakov, V. [ITEP, B. Cheremushkinskaya 25, Moscow, 117218 (Russian Federation); School of Biomedicine, Far Eastern Federal University, Sukhanova 8, Vladivostok 690950 (Russian Federation); Boyda, D. [School of Biomedicine, Far Eastern Federal University, Sukhanova 8, Vladivostok 690950 (Russian Federation); Goy, V. [School of Natural Sciences, Far Eastern Federal University, Sukhanova 8, Vladivostok 690950 (Russian Federation); Molochkov, A. [School of Biomedicine, Far Eastern Federal University, Sukhanova 8, Vladivostok 690950 (Russian Federation); Nakamura, A. [School of Biomedicine, Far Eastern Federal University, Sukhanova 8, Vladivostok 690950 (Russian Federation); Research Center for Nuclear Physics (RCNP), Osaka University, Ibaraki, Osaka, 567-0047 (Japan); Theoretical Research Division, Nishina Center, RIKEN, Wako 351-0198 (Japan); Nikolaev, A. [School of Biomedicine, Far Eastern Federal University, Sukhanova 8, Vladivostok 690950 (Russian Federation); Zakharov, V.I. [ITEP, B. Cheremushkinskaya 25, Moscow, 117218 (Russian Federation); School of Biomedicine, Far Eastern Federal University, Sukhanova 8, Vladivostok 690950 (Russian Federation); Moscow Inst Phys & Technol, Dolgoprudny, Moscow Region, 141700 (Russian Federation)

2016-12-15

We discuss our study for exploring the QCD phase diagram based on the lattice QCD. To go beyond the Taylor expansion and to reach higher density regions, we employ the canonical approach. In order to produce lattice data which meet experimental situation as much as possible, we propose a canonical approach with the charge and baryon number. We present our lattice QCD GPU code for this project which employs the clover improved Wilson fermions and Iwasaki gauge action to investigate pure imaginary chemical potential.

Lattice QCD for Baryon Rich Matter – Beyond Taylor Expansions

International Nuclear Information System (INIS)

Bornyakov, V.; Boyda, D.; Goy, V.; Molochkov, A.; Nakamura, A.; Nikolaev, A.; Zakharov, V.I.

2016-01-01

We discuss our study for exploring the QCD phase diagram based on the lattice QCD. To go beyond the Taylor expansion and to reach higher density regions, we employ the canonical approach. In order to produce lattice data which meet experimental situation as much as possible, we propose a canonical approach with the charge and baryon number. We present our lattice QCD GPU code for this project which employs the clover improved Wilson fermions and Iwasaki gauge action to investigate pure imaginary chemical potential.

Numerical simulations of thermal convection in a rotating spherical fluid shell at high Taylor and Rayleigh numbers

International Nuclear Information System (INIS)

Sun, Z.; Schubert, G.

1995-01-01

In this study, we carry out numerical simulations of thermal convection in a rapidly rotating spherical fluid shell at high Taylor number Ta and Rayleigh number R with a nonlinear, three-dimensional, time-dependent, spectral-transform code. The parameters used in the simulations are chosen to be in a range which allows us to study two different types of convection, i.e., single column and multi-layered types, and the transition between them. Numerical solutions feature highly time-dependent north--south open columnar convective cells. The cells occur irregularly in longitude, are quasi-layered in cylindrical radius, and maintain alternating bands of mean zonal flow. The complex convective structure and the banded mean zonal flow are results of the high Taylor and Rayleigh numbers. The transition between the two types of convection appears to occur gradually with increasing Rayleigh and Taylor numbers. At a Taylor number of 10 7 the differential rotation pattern consists of an inner cylindrical region of subrotation and an outer cylindrical shell of superrotation manifest at the outer boundary as an equatorial superrotation and a high latitude subrotation. The differential rotation pattern is similar at Ta=10 8 and low Rayleigh number. Cylindrical shells of alternately directed mean zonal flow begin to develop at Ta=10 8 and R=50R c and at Ta=10 9 and R=25R c . This pattern is seen on the outer surface as a latitudinally-banded zonal flow consisting of an equatorial superrotation, a middle and high latitude subrotation, and a polar superrotation. At Ta=10 9 and R=50R c the differential rotation appears at the surface as a broad eastward flow in the equatorial region with alternating bands of westward and eastward flow at high latitudes. copyright 1995 American Institute of Physics

On the ""early-time"" evolution of variables relevant to turbulence models for Rayleigh-Taylor instability

Energy Technology Data Exchange (ETDEWEB)

Rollin, Bertrand [Los Alamos National Laboratory; Andrews, Malcolm J [Los Alamos National Laboratory

2010-01-01

We present our progress toward setting initial conditions in variable density turbulence models. In particular, we concentrate our efforts on the BHR turbulence model for turbulent Rayleigh-Taylor instability. Our approach is to predict profiles of relevant parameters before the fully turbulent regime and use them as initial conditions for the turbulence model. We use an idealized model of the mixing between two interpenetrating fluids to define the initial profiles for the turbulence model parameters. Velocities and volume fractions used in the idealized mixing model are obtained respectively from a set of ordinary differential equations modeling the growth of the Rayleigh-Taylor instability and from an idealization of the density profile in the mixing layer. A comparison between predicted initial profiles for the turbulence model parameters and initial profiles of the parameters obtained from low Atwood number three dimensional simulations show reasonable agreement.

A numerical study of Taylor vortex flow in a finite length tapered annulus

International Nuclear Information System (INIS)

Noui-Mehidi, M N; Ohmura, N; Wu, J

2005-01-01

The transient evolution and steady state analysis of Taylor vortex flow in a tapered annulus was conducted by numerical experiments in the case where the inner cylinder was rotated and the outer one fixed. The gap between the cylinders was linearly tapered from a supercritical value at the upper base to the critical value at the lower base. The wavelength adjustment depended on the variation of Reynolds number in the spatially ramped gap. The axisymmetric conservative governing equations were solved by the use of an simplified marker and cell (SMAC) algorithm. A coordinate transformation function allowed us to numerically solve the problem in a rectangular computational domain. The results have shown that Taylor vortices growth was sensitive to the spatial ramp of the gap even with tapering angle values less than one degree. The interaction between the inflow and outflow boundaries could be clearly seen as the taper angle was increased. The investigation of the transient dynamics related to the flow system also revealed a characteristic dependence on the taper angle

Ablative stabilization of the Rayleigh-Taylor instability in regimes relevant to inertial confinement fusion

International Nuclear Information System (INIS)

Kilkenny, J.D.

1994-01-01

As shown elsewhere an ablatively imploded shell is hydrodynamically unstable, the dominant instability being the well known Rayleigh-Taylor instability with growth rate γ = √Akg where k = 2π/λ is the wave number, g is the acceleration and A the Attwood number (ρ hi - ρ lo )/(ρ hi + ρ lo ) where ρ hi is the density of the heavier fluid and ρ lo is the density of the lighter fluid. A theoretical understanding of ablative stabilization has gradually evolved, confirmed over the last five years by experiments. The linear growth is very well understood with excellent agreement between experiment and simulation for planar geometry with wavelengths in the region of 30--100μm. There is an accurate, albeit phenomenological dispersion relation. The non-linear growth has been measured and agrees with calculations. In this lecture, the authors go into the fundamentals of the Rayleigh-Taylor instability and the experimental measurements that show it is stabilized sufficiently by ablation in regimes relevant to ICF

Non-Newtonian Hele-Shaw Flow and the Saffman-Taylor Instability

International Nuclear Information System (INIS)

Kondic, L.; Shelley, M.J.; Palffy-Muhoray, P.

1998-01-01

We explore the Saffman-Taylor instability of a gas bubble expanding into a shear thinning liquid in a radial Hele-Shaw cell. Using Darcy close-quote s law generalized for non-Newtonian fluids, we perform simulations of the full dynamical problem. The simulations show that shear thinning significantly influences the developing interfacial patterns. Shear thinning can suppress tip splitting, and produce fingers which oscillate during growth and shed side branches. Emergent length scales show reasonable agreement with a general linear stability analysis. copyright 1998 The American Physical Society

Onset of secondary flow in the modulated Taylor-Couette system

International Nuclear Information System (INIS)

Wu, X.; Swift, J.B.

1989-01-01

The critical Reynolds number for the linear instability of primary flow is calculated for a Taylor-Couette system in which the rotation rate of either cylinder is modulated sinusoidally in time. The method used is based on that of Hall [J. Fluid Mech. 67, 29 (1975)] and is restricted to small amplitudes of modulation but allows for a finite gap. For the case of outer-cylinder modulation, we find that the critical Reynolds number is larger than that for the unmodulated system, while, if the inner cylinder is modulated, it is smaller

Gauge Symmetry and Slavnov-Taylor Identities for Randomly Stirred Fluids

International Nuclear Information System (INIS)

Berera, Arjun; Hochberg, David

2007-01-01

The path integral for randomly forced incompressible fluids is shown to have an underlying Becchi-Rouet-Stora (BRS) symmetry as a consequence of Galilean invariance. This symmetry must be respected to have a consistent generating functional, free from both an overall infinite factor and spurious relations amongst correlation functions. We present a procedure for respecting this BRS symmetry, akin to gauge fixing in quantum field theory. Relations are derived between correlation functions of this gauge-fixed, BRS symmetric theory, analogous to the Slavnov-Taylor identities of quantum field theory

The ATOMFT integrator - Using Taylor series to solve ordinary differential equations

Science.gov (United States)

Berryman, Kenneth W.; Stanford, Richard H.; Breckheimer, Peter J.

1988-01-01

This paper discusses the application of ATOMFT, an integration package based on Taylor series solution with a sophisticated user interface. ATOMFT has the capabilities to allow the implementation of user defined functions and the solution of stiff and algebraic equations. Detailed examples, including the solutions to several astrodynamics problems, are presented. Comparisons with its predecessor ATOMCC and other modern integrators indicate that ATOMFT is a fast, accurate, and easy method to use to solve many differential equation problems.

Stationary solution of the Rayleigh-Taylor instability for spatially periodic flows: questions of uniqueness, dimensionality, and universality

International Nuclear Information System (INIS)

Abarzhi, S.I.

1996-01-01

The stationary solutions of the Rayleigh-Taylor instability for spatially periodic flows with general symmetry are investigated here for the first time. The existence of a set of stationary solutions is established. The question of its dimensionality in function space is resolved on the basis of an analysis of the symmetry of the initial perturbation. The interrelationship between the dimensionality of the solution set and the symmetry of the flow is found. The dimensionality of the solution set is established for flows invariant with respect to one of five symmorphic two-dimensional groups. The nonuniversal character of the set of stationary solutions of the Rayleigh-Taylor instability is demonstrated. For flows in a tube, on the contrary, universality of the solution set, along with its independence of the symmetry of the initial perturbation, is assumed. The problem of the free boundary in the Rayleigh-Taylor instability is solved in the first two approximations, and their convergence is investigated. The dependence of the velocity and Fourier harmonics on the parameters of the problem is found. Possible symmetry violations of the flow are analyzed. Limits to previously studied cases are investigated, and their accuracy is established. Questions of the stability of the solutions obtained and the possibility of a physically correct statement of the problem are discussed

Developpement of a numerical method for Navier-Stokes equations in anelastic approximation: application to Rayleigh-Taylor instabilities

International Nuclear Information System (INIS)

Hammouch, Z.

2012-01-01

The 'anelastic' approximation allows us to filter the acoustic waves thanks to an asymptotic development of the Navier-Stokes equations, so increasing the averaged time step, during the numerical simulation of hydrodynamic instabilities development. So, the anelastic equations for a two fluid mixture in case of Rayleigh-Taylor instability are established.The linear stability of Rayleigh-Taylor flow is studied, for the first time, for perfect fluids in the anelastic approximation. We define the Stokes problem resulting from Navier-Stokes equations without the non linear terms (a part of the buoyancy is considered); the ellipticity is demonstrated, the Eigenmodes and the invariance related to the pressure are detailed. The Uzawa's method is extended to the anelastic approximation and shows the decoupling speeds in 3D, the particular case k = 0 and the spurious modes of pressure. Passing to multi-domain allowed to establish the transmission conditions.The algorithms and the implementation in the existing program are validated by comparing the Uzawa's operator in Fortran and Mathematica languages, to an experiment with incompressible fluids and results from anelastic and compressible numerical simulations. The study of the influence of the initial stratification of both fluids on the development of the Rayleigh-Taylor instability is initiated. (author) [fr

Rayleigh-Taylor analysis in a laser-induced plasma

International Nuclear Information System (INIS)

Marin, R A; Gonzales, C A; Riascos, H

2012-01-01

We report the conditions (plasma parameters) under which the Rayleigh-Taylor Instability (RTI) develops in an Al plasma produced by a Nd:Yag pulsed laser with a fluence range of 1 to 4 J/cm 2 , wavelength of 1064nm and 10Hz repetition rate. The used data correspond to different pressure values of the ambient N atmosphere. From previous works, we took the RTI growth rate form. From the perturbation theory the instability amplitude is proportional to e -ηt . Using the drag model, we calculated the plume dynamics equations integrating the instability term and plotted the instability growth profile with the delay time values to get critical numbers for it, in order to show under which conditions the RTI appears.

Alfred Klaar: berlínské reflexe rodných končin // Alfred Klaar: Berlin Reflections on the Homeland Landscape

Directory of Open Access Journals (Sweden)

Michal Topor

2017-07-01

Full Text Available The aim of the paper is to develop at least a part of a voice which is still difficult to understand in the Czech language environment, the voice of the others, (ex-rivals, the ‘expelledʼ, and to anchor it in the work and politics of remembering, registering and writing history of one specific author (we are talking about the continuity of perspective: about fidelity to images, local mythology, its logic. For thirty years, Alfred Klaar (born as Karpeles in 1848 in Prague co-established Prague discourse in German language from various positions (as a journalist, theatre critic, representative of various societies, ceremony speaker, associate professor of the local German polytechnic etc.. When he moved to Berlin in July 1899, he was almost fifty-one years old. He left his home (both in the narrow sense of the word, as well as the wider sense of ‘Austrian homeʼ, so important to him, but he always kept the world he had lived in for so long in his mind and preserved many links with it in spite of the geographical distance. He also returned to his homeland on various occasions (funerals and other ceremonies, lectures and he also remained talked about primarily among the Prague German circles; as a piece of memorabilia he was dusted and remembered in stories, and at the same time rightfully seen and honoured as a foreign envoy and speaker of compatriot cultural and political interests. Klaar spoke about Prague, his ‘father townʼ, and the lands near the Prussian border through the history of the German-speaking enclave, while Czechs only occurred sporadically in his retrospect writing. He repeated his thesis about an environment destroyed by ‘Slavic egoismʼ and belligerence, he spoke of the role of the German community in Czech lands as a heroic cultural mission, ungratefully displaced by the dominant policy of Czechisation in the second half of the 19th century, which strived to ‘impress upon the city a unilateral Slavic character

Technical requirements for Na¹⁸F PET bone imaging of patients being treated using a Taylor spatial frame.

Science.gov (United States)

Hatherly, Robert; Brolin, Fredrik; Oldner, Åsa; Sundin, Anders; Lundblad, Henrik; Maguire, Gerald Q; Jonsson, Cathrine; Jacobsson, Hans; Noz, Marilyn E

2014-03-01

Diagnosis of new bone growth in patients with compound tibia fractures or deformities treated using a Taylor spatial frame is difficult with conventional radiography because the frame obstructs the images and creates artifacts. The use of Na(18)F PET studies may help to eliminate this difficulty. Patients were positioned on the pallet of a clinical PET/CT scanner and made as comfortable as possible with their legs immobilized. One bed position covering the site of the fracture, including the Taylor spatial frame, was chosen for the study. A topogram was performed, as well as diagnostic and attenuation correction CT. The patients were given 2 MBq of Na(18)F per kilogram of body weight. A 45-min list-mode acquisition was performed starting at the time of injection, followed by a 5-min static acquisition 60 min after injection. The patients were examined 6 wk after the Taylor spatial frame had been applied and again at 3 mo to assess new bone growth. A list-mode reconstruction sequence of 1 × 1,800 and 1 × 2,700 s, as well as the 5-min static scan, allowed visualization of regional bone turnover. With Na(18)F PET/CT, it was possible to confirm regional bone turnover as a means of visualizing bone remodeling without the interference of artifacts from the Taylor spatial frame. Furthermore, dynamic list-mode acquisition allowed different sequences to be performed, enabling, for example, visualization of tracer transport from blood to the fracture site.

Shear flow stabilization of the hydromagnetic Rayleigh-Taylor instability

International Nuclear Information System (INIS)

Roderick, N.F.; Shumlak, U.; Douglas, M.; Peterkin, R.E. Jr.; Ruden, E.

1997-01-01

Numerical simulations have indicated that shear flow may help stabilize the hydromagnetic Rayleigh-Taylor instability in imploding plasma z-pinches. A simple extension to a model presented in Chandrasekhar has been developed to study the linear stability of incompressible plasma subjected to both a shear flow and acceleration. The model has been used to investigate the stability plasma implosion schemes using externally imposed velocity shear which develops from the plasma flow itself. Specific parameters were chosen to represent plasma implosions driven by the Saturn and PBFA-Z, pulsed power generators at Sandia National Laboratories. Results indicate a high shear is necessary to stabilize the z-pinch implosions studied

Theoretical and Experimental Studies of Magneto-Rayleigh-Taylor Instabilities

International Nuclear Information System (INIS)

Lau, Yue Ying; Gilgenbach, Ronald

2013-01-01

Magneto-Rayleigh-Taylor instability (MRT) is important to magnetized target fusion, wire-array z-pinches, and equation-of-state studies using flyer plates or isentropic compression. It is also important to the study of the crab nebula. The investigators performed MRT experiments on thin foils, driven by the mega-ampere linear transformer driver (LTD) facility completed in their laboratory. This is the first 1-MA LTD in the USA. Initial experiments on the seeding of MRT were performed. Also completed was an analytic study of MRT for a finite plasma slab with arbitrary magnetic fields tangential to the interfaces. The effects of magnetic shear and feedthrough were analyzed

Theoretical and Experimental Studies of Magneto-Rayleigh-Taylor Instabilities

Energy Technology Data Exchange (ETDEWEB)

Lau, Yue Ying [University of Michigan, Ann Arbor, MI (United States); Gilgenbach, Ronald [University of Michigan, Ann Arbor, MI (United States)

2013-07-07

Magneto-Rayleigh-Taylor instability (MRT) is important to magnetized target fusion, wire-array z-pinches, and equation-of-state studies using flyer plates or isentropic compression. It is also important to the study of the crab nebula. The investigators performed MRT experiments on thin foils, driven by the mega-ampere linear transformer driver (LTD) facility completed in their laboratory. This is the first 1-MA LTD in the USA. Initial experiments on the seeding of MRT were performed. Also completed was an analytic study of MRT for a finite plasma slab with arbitrary magnetic fields tangential to the interfaces. The effects of magnetic shear and feedthrough were analyzed.

Role of parallel flow curvature on the mitigation of Rayleigh-Taylor instability

International Nuclear Information System (INIS)

Sarmah, D.; Sen, S.; Cairns, R.A.

2001-01-01

The effect of a radially varying parallel equilibrium flow on the stability of the Rayleigh-Taylor (RT) mode is studied analytically in the presence of a sheared magnetic field. It is shown that the parallel flow curvature can completely stabilize the RT mode. The flow curvature also has a robust effect on the radial structure of the mode. Possible implications of these theoretical findings to recent experiments are also discussed

Taylor-series and Monte-Carlo-method uncertainty estimation of the width of a probability distribution based on varying bias and random error

International Nuclear Information System (INIS)

Wilson, Brandon M; Smith, Barton L

2013-01-01

Uncertainties are typically assumed to be constant or a linear function of the measured value; however, this is generally not true. Particle image velocimetry (PIV) is one example of a measurement technique that has highly nonlinear, time varying local uncertainties. Traditional uncertainty methods are not adequate for the estimation of the uncertainty of measurement statistics (mean and variance) in the presence of nonlinear, time varying errors. Propagation of instantaneous uncertainty estimates into measured statistics is performed allowing accurate uncertainty quantification of time-mean and statistics of measurements such as PIV. It is shown that random errors will always elevate the measured variance, and thus turbulent statistics such as u'u'-bar. Within this paper, nonlinear, time varying errors are propagated from instantaneous measurements into the measured mean and variance using the Taylor-series method. With these results and knowledge of the systematic and random uncertainty of each measurement, the uncertainty of the time-mean, the variance and covariance can be found. Applicability of the Taylor-series uncertainty equations to time varying systematic and random errors and asymmetric error distributions are demonstrated with Monte-Carlo simulations. The Taylor-series uncertainty estimates are always accurate for uncertainties on the mean quantity. The Taylor-series variance uncertainty is similar to the Monte-Carlo results for cases in which asymmetric random errors exist or the magnitude of the instantaneous variations in the random and systematic errors is near the ‘true’ variance. However, the Taylor-series method overpredicts the uncertainty in the variance as the instantaneous variations of systematic errors are large or are on the same order of magnitude as the ‘true’ variance. (paper)

Development of an empirical model of turbine efficiency using the Taylor expansion and regression analysis

International Nuclear Information System (INIS)

Fang, Xiande; Xu, Yu

2011-01-01

The empirical model of turbine efficiency is necessary for the control- and/or diagnosis-oriented simulation and useful for the simulation and analysis of dynamic performances of the turbine equipment and systems, such as air cycle refrigeration systems, power plants, turbine engines, and turbochargers. Existing empirical models of turbine efficiency are insufficient because there is no suitable form available for air cycle refrigeration turbines. This work performs a critical review of empirical models (called mean value models in some literature) of turbine efficiency and develops an empirical model in the desired form for air cycle refrigeration, the dominant cooling approach in aircraft environmental control systems. The Taylor series and regression analysis are used to build the model, with the Taylor series being used to expand functions with the polytropic exponent and the regression analysis to finalize the model. The measured data of a turbocharger turbine and two air cycle refrigeration turbines are used for the regression analysis. The proposed model is compact and able to present the turbine efficiency map. Its predictions agree with the measured data very well, with the corrected coefficient of determination R c 2 ≥ 0.96 and the mean absolute percentage deviation = 1.19% for the three turbines. -- Highlights: → Performed a critical review of empirical models of turbine efficiency. → Developed an empirical model in the desired form for air cycle refrigeration, using the Taylor expansion and regression analysis. → Verified the method for developing the empirical model. → Verified the model.

Experimental study of single taylor bubbles rising in stagnant liquid mixtures inside of vertical tubes

International Nuclear Information System (INIS)

Azevedo, Marcos B. de; Faccini, Jose L.H.; Su, Jian

2015-01-01

The present work reports an experimental study of single Taylor bubbles rising in vertical tubes filled with water-glycerin mixtures by using the pulse-echo ultrasonic technique. A 2m long acrylic tube with inner diameter of 24 mm was used in the experiments. Initially, the tube was sealed at the ends and filled partially with the liquid mixtures to leave an air pocket of length L 0 at the top end. A Taylor bubble was formed by the inversion of the tube. The rising bubbles were detected by ultrasonic transducers located at the upper part of the tube. The velocity, the length and the pro le of the bubbles and the thickness of the liquid lm around them were obtained from the ultrasonic signals processing. The liquid lm thickness in the vertical tube was also determined by a graphic method that relates the bubble length L b with the initial length of the air pocket L 0 . It was observed that the bubble velocity decreased with increasing viscosity, while the lm thickness increased. It was shown that the liquid lm thickness determined by the graphic method fitted well the higher viscosities data, but overestimated the lower viscosities data. Additionally, the results indicated that some correlations developed to estimate the thickness of liquid films falling down inside/outside of tubes and down a plane surface could be applied to estimate the thickness of liquid films falling around Taylor bubbles in an Inverse Viscosity Number (N f ) range different to those considered in the literature. (author)

Three-dimensional, nonlinear evolution of the Rayleigh--Taylor instability of a thin layer

International Nuclear Information System (INIS)

Manheimer, W.; Colombant, D.; Ott, E.

1984-01-01

A numerical simulation scheme is developed to examine the nonlinear evolution of the Rayleigh--Taylor instability of a thin sheet in three dimensions. It is shown that the erosion of mass at the top of the bubble is approximately as described by two-dimensional simulations. However, mass is lost into spikes more slowly in three-dimensional than in two-dimensional simulations

Three-dimensional Rayleigh-Taylor convection of miscible fluids in a porous medium

Science.gov (United States)

Suekane, Tetsuya; Nakanishi, Yuji; Wang, Lei

2017-11-01

Natural convection of miscible fluids in a porous medium is relevant for fields, such as geoscience and geoengineering, and for the geological storage of CO2. In this study, we use X-ray computer tomography to visualize 3D fingering structures associated with the Rayleigh-Taylor instability between miscible fluids in a porous medium. In the early stages of the onset of the Rayleigh-Taylor instability, a fine crinkling pattern gradually appears at the interface. As the wavelength and amplitude increase, descending fingers form on the interface and extend vertically downward; moreover, ascending and highly symmetric fingers form. The adjacent fingers are cylindrical in shape and coalesce to form large fingers. Fingers appearing on the interface tend to become finer with increasing Rayleigh number, which is consistent with linear perturbation theory. If the Péclet number exceeds 10, the transverse dispersion increases the finger diameter and enhances finger coalescence, strongly impacting the decay in finger number density. When mechanical dispersion is negligible, the finger-extension velocity, the mass-transfer rate, and the onset time scale with Rayleigh number. Mechanical dispersion not only reduces the onset time but also enhances mass transport, which indicates that mechanical dispersion influences the long-term dissolution process of CO2 injected into aquifers.

On the ""early-time"" evolution of variables relevant to turbulence models for the Rayleigh-Taylor instability

Energy Technology Data Exchange (ETDEWEB)

Rollin, Bertrand [Los Alamos National Laboratory; Andrews, Malcolm J [Los Alamos National Laboratory

2010-01-01

We present our progress toward setting initial conditions in variable density turbulence models. In particular, we concentrate our efforts on the BHR turbulence model for turbulent Rayleigh-Taylor instability. Our approach is to predict profiles of relevant variables before fully turbulent regime and use them as initial conditions for the turbulence model. We use an idealized model of mixing between two interpenetrating fluids to define the initial profiles for the turbulence model variables. Velocities and volume fractions used in the idealized mixing model are obtained respectively from a set of ordinary differential equations modeling the growth of the Rayleigh-Taylor instability and from an idealization of the density profile in the mixing layer. A comparison between predicted profiles for the turbulence model variables and profiles of the variables obtained from low Atwood number three dimensional simulations show reasonable agreement.

An h-p Taylor-Galerkin finite element method for compressible Euler equations

Science.gov (United States)

Demkowicz, L.; Oden, J. T.; Rachowicz, W.; Hardy, O.

1991-01-01

An extension of the familiar Taylor-Galerkin method to arbitrary h-p spatial approximations is proposed. Boundary conditions are analyzed, and a linear stability result for arbitrary meshes is given, showing the unconditional stability for the parameter of implicitness alpha not less than 0.5. The wedge and blunt body problems are solved with both linear, quadratic, and cubic elements and h-adaptivity, showing the feasibility of higher orders of approximation for problems with shocks.

Experimental investigation of turbulent mixing by Rayleigh-Taylor instability

International Nuclear Information System (INIS)

Youngs, D.L.

1992-01-01

A key feature of compressible turbulent mixing is the generation of vorticity via the ∇px ∇(1/ρ) term. This source of vorticity is also present in incompressible flows involving the mixing of fluids of different density, for example Rayleigh-Taylor unstable flows. This paper gives a summary of an experimental investigation of turbulent mixing at a plane boundary between two fluids, of densities ρ 1 , and ρ 2 . (ρ 1 > ρ 2 ) due to Rayleigh-Taylor instability. The two fluids are near incompressible and mixing occurs when an approximately constant acceleration, g, is applied normal to the interface with direction from fluid 2 to fluid 1. Full details of the experimental programme are given in a set of three reports. Some of the earlier experiments are also described by Read. Previous experimental work and much of the theoretical research has concentrated on studying the growth of the instability from a single wavelength perturbation rather than turbulent mixing. Notable exceptions are published in the Russian literature. A related process, turbulent mixing induced by the passage of shock waves though an interface between fluids of different density is described by Andronov et al. The major purpose of the experiments described here was to study the evolution of the instability from small random perturbations where it is found that large and larger structures appear as time proceeds. A novel technique was used to provide the desired acceleration. The two fluids were enclosed in a rectangular tank, the lighter fluid 2 initially resting on top of the denser fluid 1. One or more rocket motors were then used to drive the tank vertically downwards. The aim of the experimental programme is to provide data for the calibration of a turbulence model used to predict mixing in real situations

Front propagation in Rayleigh-Taylor systems with reaction

International Nuclear Information System (INIS)

Scagliarini, A; Biferale, L; Sbragaglia, M; Mantovani, F; Pivanti, M; Schifano, S F; Tripiccione, R; Pozzati, F; Toschi, F

2011-01-01

A special feature of Rayleigh-Taylor systems with chemical reactions is the competition between turbulent mixing and the 'burning processes', which leads to a highly non-trivial dynamics. We studied the problem performing high resolution numerical simulations of a 2d system, using a thermal lattice Boltzmann (LB) model. We spanned the various regimes emerging at changing the relative chemical/turbulent time scales, from slow to fast reaction; in the former case we found numerical evidence of an enhancement of the front propagation speed (with respect to the laminar case), providing a phenomenological argument to explain the observed behaviour. When the reaction is very fast, instead, the formation of sharp fronts separating patches of pure phases, leads to an increase of intermittency in the small scale statistics of the temperature field.

The ornithologist Alfred Russel Wallace and the controversy surrounding the dinosaurian origin of birds.

Science.gov (United States)

Ibrahim, Nizar; Kutschera, Ulrich

2013-12-01

Over many years of his life, the British naturalist Alfred Russel Wallace (1823-1913) explored the tropical forests of Malaysia, collecting numerous specimens, including hundreds of birds, many of them new to science. Subsequently, Wallace published a series of papers on systematic ornithology, and discovered a new species on top of a volcano on Ternate, where he wrote, in 1858, his famous essay on natural selection. Based on this hands-on experience, and an analysis of an Archaeopteryx fossil, Wallace suggested that birds may have descended from dinosaurian ancestors. Here, we describe the "dinosaur-bird hypothesis" that originated with the work of Thomas H. Huxley (1825-1895). We present the strong evidence linking theropod dinosaurs to birds, and briefly outline the long and ongoing controversy around this concept. Dinosaurs preserving plumage, nesting sites and trace fossils provide overwhelming evidence for the dinosaurian origin of birds. Based on these recent findings of paleontological research, we conclude that extant birds indeed descended, with some modifications, from small, Mesozoic theropod dinosaurs. In the light of Wallace's view of bird origins, we critically evaluate recent opposing views to this idea, including Ernst Mayr's (1904-2005) arguments against the "dinosaur-bird hypothesis", and document that this famous ornithologist was not correct in his assessment of this important aspect of vertebrate evolution.

Using a High-Resolution Ensemble Modeling Method to Inform Risk-Based Decision-Making at Taylor Park Dam, Colorado

Science.gov (United States)

Mueller, M.; Mahoney, K. M.; Holman, K. D.

2015-12-01

The Bureau of Reclamation (Reclamation) is responsible for the safety of Taylor Park Dam, located in central Colorado at an elevation of 9300 feet. A key aspect of dam safety is anticipating extreme precipitation, runoff and the associated inflow of water to the reservoir within a probabilistic framework for risk analyses. The Cooperative Institute for Research in Environmental Sciences (CIRES) has partnered with Reclamation to improve understanding and estimation of precipitation in the western United States, including the Taylor Park watershed. A significant challenge is that Taylor Park Dam is located in a relatively data-sparse region, surrounded by mountains exceeding 12,000 feet. To better estimate heavy precipitation events in this basin, a high-resolution modeling approach is used. The Weather Research and Forecasting (WRF) model is employed to simulate events that have produced observed peaks in streamflow at the location of interest. Importantly, an ensemble of model simulations are run on each event so that uncertainty bounds (i.e., forecast error) may be provided such that the model outputs may be more effectively used in Reclamation's risk assessment framework. Model estimates of precipitation (and the uncertainty thereof) are then used in rainfall runoff models to determine the probability of inflows to the reservoir for use in Reclamation's dam safety risk analyses.

Estimativa do coeficiente Priestley-Taylor em floresta monodominante Cambarazal no Pantanal Estimation of the Priestley-Taylor coefficient in the monospecific forest in northern Pantanal, Brazil

Directory of Open Access Journals (Sweden)

Luciana Sanches

2010-12-01

Full Text Available O coeficiente Priestley-Taylor (α foi calculado baseado na estimativa da evapotranspiração pelo método de Bowen para floresta monodominante Vochysia divergens no Pantanal, Brasil. A área em estudo estava localizada no noroeste do Pantanal a aproximadamente 160 km de Cuiabá, Mato Grossso, Brasil (16º39'50''S; 56º47'50''O. Medições micrometeorológicas contínuas, em uma torre a uma altura de 32 m de altura, foram feitas de janeiro a dezembro de 2007. A evapotranspiração variou de 2,50 mm dia-1 (estação seca a 4,10 mm dia-1 (estação úmida. O coeficiente Pristley-Taylor (α variou durante o ano com valores máximos e mínimos nas estações seca e úmida, respectivamente, com média anual de 0,65 ± 0,18 de acordo com o padrão climático da área em estudo em função do aumento do conteúdo de água no solo/lâmina d'água de inundação e/ou diminuição na demanda evaporativa. Com a determinação empírica das dimensões de α, as estimativas da evapotranspiração podem ser melhoradas para florestas de Vochysia divergens na planície de inundação do Pantanal.The Priestley-Taylor coefficient (α was calculated based on the Bowen method evapotranspiration estimative for Vochysia divergens monospecific forests in Pantanal, Brazil. The study area was located at the northeastern Pantanal, approximately 160 km from Cuiabá city, Mato Grosso State, Brazil (16º39'50''S; 56º47'50''W. Continuous micrometeorological flux measurements at a 32 m tower height were made from January to December of 2007. The evapotranspiration ranged from 2.26 mm day-1 (dry season to 4.50 mm day-1 (wet season. The average estimated α value ranged along the year from a maximum and a minimum during the dry and wet season respectively, with an annual average of 0.65±0.18 according to the weather pattern over the study area due to the increase of water content in soil/water flooding depth and/or decrease in evaporative demand. Based on empirical α values

Taylor dispersion in premixed combustion: Questions from turbulent combustion answered for laminar flames

Science.gov (United States)

Daou, Joel; Pearce, Philip; Al-Malki, Faisal

2018-02-01

We present a study of Taylor dispersion in premixed combustion and use it to clarify fundamental issues related to flame propagation in a flow field. In particular, simple analytical formulas are derived for variable density laminar flames with arbitrary Lewis number Le providing clear answers to important questions arising in turbulent combustion, when these questions are posed for the case of one-scale laminar parallel flows. Exploiting, in the context of a laminar Poiseuille flow model, a thick flame distinguished asymptotic limit for which the flow amplitude is large with the Reynolds number Re fixed, three main contributions are made. First, a link is established between Taylor dispersion [G. Taylor, Proc. R. Soc. London Ser. A 219, 186 (1953), 10.1098/rspa.1953.0139] and Damköhler's second hypothesis [G. Damköhler, Ber. Bunsen. Phys. Chem. 46, 601 (1940)] by describing analytically the enhancement of the effective propagation speed UT due to small flow scales. More precisely, it is shown that Damköhler's hypothesis is only partially correct for one-scale parallel laminar flows. Specifically, while the increase in UT due to the flow is shown to be directly associated with the increase in the effective diffusivity as suggested by Damköhler, our results imply that UT˜Re (for Re≫1 ) rather than UT˜√{Re} , as implied by Damköhler's hypothesis. Second, it is demonstrated analytically and confirmed numerically that, when UT is plotted versus the flow amplitude for fixed values of Re, the curve levels off to a constant value depending on Re. We may refer to this effect as the laminar bending effect as it mimics a similar bending effect known in turbulent combustion. Third, somewhat surprising implications associated with the dependence of UT and of the effective Lewis number Leeff on the flow are reported. For example, Leeff is found to vary from Le to Le-1 as Re varies from small to large values. Also, UT is found to be a monotonically increasing function

Conditional sampling technique to test the applicability of the Taylor hypothesis for the large-scale coherent structures

Science.gov (United States)

Hussain, A. K. M. F.

1980-01-01

Comparisons of the distributions of large scale structures in turbulent flow with distributions based on time dependent signals from stationary probes and the Taylor hypothesis are presented. The study investigated an area in the near field of a 7.62 cm circular air jet at a Re of 32,000, specifically having coherent structures through small-amplitude controlled excitation and stable vortex pairing in the jet column mode. Hot-wire and X-wire anemometry were employed to establish phase averaged spatial distributions of longitudinal and lateral velocities, coherent Reynolds stress and vorticity, background turbulent intensities, streamlines and pseudo-stream functions. The Taylor hypothesis was used to calculate spatial distributions of the phase-averaged properties, with results indicating that the usage of the local time-average velocity or streamwise velocity produces large distortions.

Modified Taylor series method for solving nonlinear differential equations with mixed boundary conditions defined on finite intervals.

Science.gov (United States)

Vazquez-Leal, Hector; Benhammouda, Brahim; Filobello-Nino, Uriel Antonio; Sarmiento-Reyes, Arturo; Jimenez-Fernandez, Victor Manuel; Marin-Hernandez, Antonio; Herrera-May, Agustin Leobardo; Diaz-Sanchez, Alejandro; Huerta-Chua, Jesus

2014-01-01

In this article, we propose the application of a modified Taylor series method (MTSM) for the approximation of nonlinear problems described on finite intervals. The issue of Taylor series method with mixed boundary conditions is circumvented using shooting constants and extra derivatives of the problem. In order to show the benefits of this proposal, three different kinds of problems are solved: three-point boundary valued problem (BVP) of third-order with a hyperbolic sine nonlinearity, two-point BVP for a second-order nonlinear differential equation with an exponential nonlinearity, and a two-point BVP for a third-order nonlinear differential equation with a radical nonlinearity. The result shows that the MTSM method is capable to generate easily computable and highly accurate approximations for nonlinear equations. 34L30.

Evaluation of Dynamic Deformation Behaviors in Metallic Materials under High Strain-Rates Using Taylor Bar Impact Test

Energy Technology Data Exchange (ETDEWEB)

Bae, Kyung Oh; Shin, Hyung Seop [Andong National Univ., Andong (Korea, Republic of)

2016-09-15

To ensure the reliability and safety of various mechanical systems in accordance with their high-speed usage, it is necessary to evaluate the dynamic deformation behavior of structural materials under impact load. However, it is not easy to understand the dynamic deformation behavior of the structural materials using experimental methods in the high strain-rate range exceeding 10{sup 4} s{sup -1}. In this study, the Taylor bar impact test was conducted to investigate the dynamic deformation behavior of metallic materials in the high strain-rate region, using a high-speed photography system. Numerical analysis of the Taylor bar impact test was performed using AUTODYN S/W. The results of the analysis were compared with the experimental results, and the material behavior in the high strain-rate region was discussed.

Differences between Experts' and Students' Conceptual Images of the Mathematical Structure of Taylor Series Convergence

Science.gov (United States)

Martin, Jason

2013-01-01

Taylor series convergence is a complicated mathematical structure which incorporates multiple concepts. Therefore, it can be very difficult for students to initially comprehend. How might students make sense of this structure? How might experts make sense of this structure? To answer these questions, an exploratory study was conducted using…

Approximate Expressions for the Period of a Simple Pendulum Using a Taylor Series Expansion

Science.gov (United States)

Belendez, Augusto; Arribas, Enrique; Marquez, Andres; Ortuno, Manuel; Gallego, Sergi

2011-01-01

An approximate scheme for obtaining the period of a simple pendulum for large-amplitude oscillations is analysed and discussed. When students express the exact frequency or the period of a simple pendulum as a function of the oscillation amplitude, and they are told to expand this function in a Taylor series, they always do so using the…

Direct Numerical Simulations of Rayleigh-Taylor instability

International Nuclear Information System (INIS)

Livescu, D; Wei, T; Petersen, M R

2011-01-01

The development of the Rayleigh-Taylor mixing layer is studied using data from an extensive new set of Direct Numerical Simulations (DNS), performed on the 0.5 Petaflops, 150k compute cores BG/L Dawn supercomputer at Lawrence Livermore National Laboratory. This includes a suite of simulations with grid size of 1024 2 × 4608 and Atwood number ranging from 0.04 to 0.9, in order to examine small departures from the Boussinesq approximation as well as large Atwood number effects, and a high resolution simulation of grid size 4096 2 × 4032 and Atwood number of 0.75. After the layer width had developed substantially, additional branched simulations have been run under reversed and zero gravity conditions. While the bulk of the results will be published elsewhere, here we present preliminary results on: 1) the long-standing open question regarding the discrepancy between the numerically and experimentally measured mixing layer growth rates and 2) mixing characteristics.

What is certain and what is not so certain in our knowledge of Rayleigh-Taylor mixing?

International Nuclear Information System (INIS)

Anisimov, Sergei I.; Drake, R. Paul; Gauthier, Serge; Meshkov, Evgeny E.; Abarzhi, Snezhana I.

2013-01-01

Past decades significantly advanced our understanding of Rayleigh-Taylor (RT) mixing. We briefly review recent theoretical results and numerical modelling approaches and compare them with state of the art experiments focusing the reader's attention on qualitative properties of RT mixing. (authors)

PSYCHOLOGY IN FRENCH ACADEMIC PUBLISHING IN THE LATE NINETEENTH CENTURY: ALFRED BINET, EDITORIAL DIRECTOR AT THE SCHLEICHER PUBLISHING HOUSE.

Science.gov (United States)

Nicolas, Serge

2015-01-01

To date, historians of psychology have largely ignored the role of academic publishing and the editorial policies of the late nineteenth century. This paper analyzes the role played by academic publishing in the history of psychology in the specific case of France, a country that provides a very interesting and unique model. Up until the middle of the 1890s, there was no collection specifically dedicated to psychology. Alfred Binet was the first to found, in 1897, a collection of works specifically dedicated to scientific psychology. He chose to work with Reinwald-Schleicher. However, Binet was soon confronted with (1) competition from other French publishing houses, and (2) Schleicher's management and editorial problems that were to sound the death knell for Binet's emerging editorial ambitions. The intention of this paper is to encourage the efforts of the pioneers of modern psychology to have their work published and disseminated. © 2015 Wiley Periodicals, Inc.

Critical condition for the transformation from Taylor cone to cone-jet

International Nuclear Information System (INIS)

Wei Cheng; Zhao Yang; Gang Tie-Qiang; Chen Li-Jie

2014-01-01

An energy method is proposed to investigate the critical transformation condition from a Taylor cone to a cone-jet. Based on the kinetic theorem, the system power allocation and the electrohydrodynamics stability are discussed. The numerical results indicate that the energy of the liquid cone tip experiences a maximum value during the transformation. With the proposed jetting energy, we give the critical transformation condition under which the derivative of jetting energy with respect to the surface area is greater than or equal to the energy required to form a unit of new liquid surface

Viète's Formula and an Error Bound without Taylor's Theorem

Science.gov (United States)

Boucher, Chris

2018-01-01

This note presents a derivation of Viète's classic product approximation of pi that relies on only the Pythagorean Theorem. We also give a simple error bound for the approximation that, while not optimal, still reveals the exponential convergence of the approximation and whose derivation does not require Taylor's Theorem.

The Magnetic Rayleigh-Taylor Instability in Astrophysical Discs

Science.gov (United States)

Contopoulos, I.; Kazanas, D.; Papadopoulos, D. B.

2016-01-01

This is our first study of the magnetic Rayleigh-Taylor instability at the inner edge of an astrophysical disc around a central back hole. We derive the equations governing small-amplitude oscillations in general relativistic ideal magnetodydrodynamics and obtain a criterion for the onset of the instability. We suggest that static disc configurations where magnetic field is held by the disc material are unstable around a Schwarzschild black hole. On the other hand, we find that such configurations are stabilized by the space-time rotation around a Kerr black hole. We obtain a crude estimate of the maximum amount of poloidal magnetic flux that can be accumulated around the centre, and suggest that it is proportional to the black hole spin. Finally, we discuss the astrophysical implications of our result for the theoretical and observational estimations of the black hole jet power.

The incept of ejection from a fresh Taylor cone and subsequent evolution

Science.gov (United States)

Lopez-Herrera, Jose M.; Ganan-Calvo, Alfonso

2017-11-01

Within a certain range of applied voltages, a pendant drop suddenly subject to an intense electric field develops a cusp from which a fast liquid ligament issues. The incept of this process has common roots with other related phenomena like the Worthington jets, the jet issued after surface bubble bursting or the impact of a drop on a liquid pool. This is experimentally and numerically demonstrated. However, given the electrohydrodynamic nature of the driver in the formation of a Taylor cone, a number of electrokinetic processes take place in the rapid tapering flow, whose characteristic times should be carefully compared to the ones of the flow. As a result, universal scaling laws for the size and charge of the top drop have been obtained. Subsequently, sustaining the applied electric field, the ejection continues and the issuing liquid ligament releases a train of droplets of varying size and charge. Under appropriate conditions and if the liquid suctioned by the electric field is replenished, the system reaches a (quasi)steady state asymptotically. The degree of compliance of the size and charge of those subsequent droplets with previously proposed scaling laws of steady Taylor cone-jets has been studied. Computational code Gerris and an extended electrokinetic module is used. This work was supported by the Ministerio de Economia y Competitividad, Plan Estatal 2013-2016 Retos, project DPI2016-78887-C3-1-R.

Experimental Study on Momentum Transfer of Surface Texture in Taylor-Couette Flow

Science.gov (United States)

Xue, Yabo; Yao, Zhenqiang; Cheng, De

2017-05-01

The behavior of Taylor-Couette (TC) flow has been extensively studied. However, no suitable torque prediction models exist for high-capacity fluid machinery. The Eckhardt-Grossmann-Lohse (EGL) theory, derived based on the Navier-Stokes equations, is proposed to model torque behavior. This theory suggests that surfaces are the significant energy transfer interfaces between cylinders and annular flow. This study mainly focuses on the effects of surface texture on momentum transfer behavior through global torque measurement. First, a power-law torque behavior model is built to reveal the relationship between dimensionless torque and the Taylor number based on the EGL theory. Second, TC flow apparatus is designed and built based on the CNC machine tool to verify the torque behavior model. Third, four surface texture films are tested to check the effects of surface texture on momentum transfer. A stereo microscope and three-dimensional topography instrument are employed to analyze surface morphology. Global torque behavior is measured by rotating a multi component dynamometer, and the effects of surface texture on the annular flow behavior are observed via images obtained using a high-speed camera. Finally, torque behaviors under four different surface conditions are fitted and compared. The experimental results indicate that surface textures have a remarkable influence on torque behavior, and that the peak roughness of surface texture enhances the momentum transfer by strengthening the fluctuation in the TC flow.

78 FR 61451 - Endangered and Threatened Wildlife and Plants; Determination of Endangered Status for the Taylor...

Science.gov (United States)

2013-10-03

...); and Pesticide use (potential threat for the Taylor's checkerspot butterfly). Peer Review and Public... scientifically sound data, assumptions, and analyses. We invited these peer reviewers to comment on our listing... known as iridoid glycosides, which have been recognized to influence the selection of oviposition sites...

Elaboration of a neural network for classification of Taylors bubbles in vertical pipes using Monte Carlo simulation for the training phase

Energy Technology Data Exchange (ETDEWEB)

Schuabb, Pablo G.; Medeiros, Jose A.C.C.; Schirru, Roberto, E-mail: pablogs@poli.ufrj.br, E-mail: canedo@lmp.ufrj.br, E-mail: schirru@lmp.ufrj.br [Corrdenacao dos Programas de Pos-Graduacao em Engenharia (PEN/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear

2015-07-01

The increase of the diameter of a spherical bubble deforms its shape, after which it moves along the vertical center of the pipeline. The Taylor's flow has bubbles with the form of a bullet and increases in the bubble's volume are seen by an enlargement of their length making that kind of bubble easily identified using gamma ray attenuation which is simulated via the software MCNPX that uses the Monte Carlo probabilistic method to simulate radiation-matter interactions. The simulations show that there exists a relation among the counts of a detector and the rising movement of a Taylor's Bubble. A database could be made to answer queries on the dimensions of a Taylor bubble for given readings of a detector, approach that would require a huge database. To make that association an Artificial Neural Network is proposed. The network can be trained with a finite number of samples that is enough to make the network able to classify data of not known bubbles simulated via MCNPX or measured on field. (author)

Elaboration of a neural network for classification of Taylors bubbles in vertical pipes using Monte Carlo simulation for the training phase

International Nuclear Information System (INIS)

Schuabb, Pablo G.; Medeiros, Jose A.C.C.; Schirru, Roberto

2015-01-01

The increase of the diameter of a spherical bubble deforms its shape, after which it moves along the vertical center of the pipeline. The Taylor's flow has bubbles with the form of a bullet and increases in the bubble's volume are seen by an enlargement of their length making that kind of bubble easily identified using gamma ray attenuation which is simulated via the software MCNPX that uses the Monte Carlo probabilistic method to simulate radiation-matter interactions. The simulations show that there exists a relation among the counts of a detector and the rising movement of a Taylor's Bubble. A database could be made to answer queries on the dimensions of a Taylor bubble for given readings of a detector, approach that would require a huge database. To make that association an Artificial Neural Network is proposed. The network can be trained with a finite number of samples that is enough to make the network able to classify data of not known bubbles simulated via MCNPX or measured on field. (author)

Pade approximants for entire functions with regularly decreasing Taylor coefficients

International Nuclear Information System (INIS)

Rusak, V N; Starovoitov, A P

2002-01-01

For a class of entire functions the asymptotic behaviour of the Hadamard determinants D n,m as 0≤m≤m(n)→∞ and n→∞ is described. This enables one to study the behaviour of parabolic sequences from Pade and Chebyshev tables for many individual entire functions. The central result of the paper is as follows: for some sequences {(n,m(n))} in certain classes of entire functions (with regular Taylor coefficients) the Pade approximants {π n,m(n) }, which provide the locally best possible rational approximations, converge to the given function uniformly on the compact set D={z:|z|≤1} with asymptotically best rate

Initial value problem for Rayleigh--Taylor instability of viscous fluids

International Nuclear Information System (INIS)

Menikoff, R.; Mjolsness, R.C.; Sharp, D.H.; Zemach, C.; Doyle, B.J.

1978-01-01

The initial value problem associated with the development of small amplitude disturbances in Rayleigh--Taylor unstable, viscous, incompressible fluids is studied. Solutions to the linearized equations of motion which satisfy general initial conditions are obtained in terms of Fourier--Laplace transforms of the hydrodynamic variables, without restriction on the density or viscosity of either fluid. When the two fluids have equal kinematic viscosities, these transforms can be inverted explicitly to express the fluid variables as integrals of Green's functions multiplied by initial data. In addition to normal modes, a set of continuum modes, not treated explicitly in the literature, makes an important contribution to the development of the fluid motion

Circulation of electrolyte in an electrochemical cell, using Taylor vortices

Energy Technology Data Exchange (ETDEWEB)

Thornton, J D

1990-05-30

In an electrochemical cell for decomposition of organic waste liquids having an anode compartment and a cathode compartment separated by a porous pot, the anode is driven by a shaft having an axial passage extending from an upper inlet in the vicinity of the liquid level to a lower outlet adjacent a turbine. The rotating anode produces Taylor vortices in annular space and liquid is drawn from layer through passage and emerges to contact the anode. In one use, organic solvent such as tributyl phosphate/odourless kerosene is destroyed. Fresh solvent is added through an inlet. A helical cooler may also be provided. (author).

Earth's core formation due to the Rayleigh-Taylor instability

International Nuclear Information System (INIS)

Ida, S.; Nakagawa, Y.; Nakazawa, K.

1987-01-01

A protoearth accretion stage configuration consisting of an undifferentiated solid core, an intermediate metal-melt layer, and an outer silicate-melt layer, is presently taken as the initial state in an investigation of Rayleigh-Taylor instability-induced core formation. The Ida et al. (to be published) quantitative results on the instability in a self-gravitating fluid sphere are used. The instability is found to occur through the translational mode on a time-scale of about 10 hr, in the case where the metal-melt layer is greater than about 1 km; this implies that the earth's core formed due to the undifferentiated solid core's translation upon the outer layer's melting. Differentiation would then have occurred in the late accretion stage. 17 references

First observation of density profile in directly laser-driven polystyrene targets for ablative Rayleigh-Taylor instability research

International Nuclear Information System (INIS)

Fujioka, Shinsuke; Shiraga, Hiroyuki; Nishikino, Masaharu; Shigemori, Keisuke; Sunahara, Atsushi; Nakai, Mitsuo; Azechi, Hiroshi; Nishihara, Katsunobu; Yamanaka, Tatsuhiko

2003-01-01

The temporal evolution of the density profile of a directly laser-driven polystyrene target was observed for the first time using an x-ray penumbral imaging technique coupled with side-on x-ray backlighting at the GEKKO XII [C. Yamanaka et al., IEEE J. Quantum Electron. QE-17, 1639 (1981)]-High Intensity Plasma Experimental Research laser facility (I L =0.7x10 14 W/cm 2 , λ L =0.35 μm). This density measurement makes it possible to experimentally confirm all physical parameters [γ(k),k,g,m,ρ a ,L m ] appearing in the modified Takabe formula for the growth rate of the ablative Rayleigh-Taylor instability. The measured density profiles were well reproduced by a one-dimensional hydrodynamic simulation code. The density measurement contributes toward fully understanding the ablative Rayleigh-Taylor instability

On power series expansions of the S-resolvent operator and the Taylor formula

Science.gov (United States)

Colombo, Fabrizio; Gantner, Jonathan

2016-12-01

The S-functional calculus is based on the theory of slice hyperholomorphic functions and it defines functions of n-tuples of not necessarily commuting operators or of quaternionic operators. This calculus relays on the notion of S-spectrum and of S-resolvent operator. Since most of the properties that hold for the Riesz-Dunford functional calculus extend to the S-functional calculus, it can be considered its non commutative version. In this paper we show that the Taylor formula of the Riesz-Dunford functional calculus can be generalized to the S-functional calculus. The proof is not a trivial extension of the classical case because there are several obstructions due to the non commutativity of the setting in which we work that have to be overcome. To prove the Taylor formula we need to introduce a new series expansion of the S-resolvent operators associated to the sum of two n-tuples of operators. This result is a crucial step in the proof of our main results, but it is also of independent interest because it gives a new series expansion for the S-resolvent operators. This paper is addressed to researchers working in operator theory and in hypercomplex analysis.

Statistic derivation of Taylor factors for polycrystalline metals with application to pure magnesium

International Nuclear Information System (INIS)

Shen, J.H.; Li, Y.L.; Wei, Q.

2013-01-01

We have investigated the Taylor factors of textured as well as texture-free polycrystalline aggregates. We begin with examining the Schmid factors of single crystals. A statistical model is then introduced to describe the distribution of grain orientations as well as the Schmid factor of individual grains of the polycrystalline system. The grains are classified into “soft” and “hard” ones. Based on this, a model is proposed for the derivation of the Taylor factors of textured as well as texture-free polycrystalline metals, and as a case study it is applied to polycrystalline magnesium. The model predictions are in very good agreement with the available experimental results. No free parameters have been involved in the development of this model, and the physical processes are clearly defined. Based on the fundamental assumption that grains can be classified into “soft” and “hard” in metals, this model should also be applicable to other hexagonal close packed metals such as α-titanium, beryllium and zirconium, as well as metals of other lattice structures such as face-centered cubic and body-centered cubic. It will also be interesting to see if this model can be incorporated into existing crystal plasticity models for the prediction of texture evolution under mechanical loading

¿Por qué existe el Estado y no más bien la anarquía? (El anarco-comunitarismo de Michael Taylor

Directory of Open Access Journals (Sweden)

Rivera, Juan Antonio

1996-04-01

Full Text Available Not available.

Se expone la perspectiva anarco-comunitarísta de Michael Taylor, y se la distingue de la anarco-capitalista de autores como Murray Rothbard, David Friedman o, en menor medida, Robert Nozick. El anarco- comunitarismo de Taylor está sólidamente asentado en la teoría de juegos; concretamente, en los análisis dinámicos del Dilema del Prisionero. Sobre la base de estos análisis, a los que el propio autor ha hecho contribuciones sustanciales, se pone de relieve la inviabilidad práctica de una anarquía perfecta, sin controles sociales externos. Pero Taylor muestra que hay, con todo, lugar para un orden social sostenido en controles informales y ampliamente descentralizados, es decir, fundado en vínculos comunitarios, y que ésta ha sido la solución al problema del orden social durante la mayor parte de la historia de la especie. Se discuten luego las circunstancias que presumiblemente dieron lugar a la crisis y obsolescencia de la solución anarco-comunitarista y su sustitución por la respuesta institucional basada en la presencia del Estado. Se concluye el escrito ensalzando los méritos teóricos de Taylor pero poniendo en duda la validez de los presupuestos valorativos que animan sus modestas proposiciones de cambio social.

Census Report: Volume V, 1986. Sanitized Version.

Science.gov (United States)

1991-04-01

0. 0599 OWAIS, MUHAMMAD 0954 OWEN, STEVEN R. 0916 OWENS, CLINT G. 0599 OWENS, GREGORY 0599 OWENS, RUSSELL E. 0837 OZDEMIR, LEVENT 0916 PACHECO, ERNEST...ORG NAME CODE SUSHINSKI, THOMAS C. 0916 SUTHERLAND , DEAN R. 0837 SVADBA, KEITH A. 0599 SVOBODA, THOMAS R. 0637 SWAIN, JEFFREY MANNING 0916 SWAIN

Rayleigh-Taylor instabilities in indirect laser drive with rugby-shaped hohlraums; Experiences d'instabilites Rayleigh-Taylor en attaque indirecte avec des cavites rugby

Energy Technology Data Exchange (ETDEWEB)

Casner, A.; Galmiche, D.; Huser, G.; Jadaud, J.P.; Richard, A.; Liberatore, S.; Vandenboomgaerde, M. [CEA Bruyeres-le-Chatel, 91 (France)

2009-07-01

The mastering of the development of hydrodynamic instabilities like Rayleigh-Taylor instabilities is an important milestone on the way to perform efficient laser implosions. The complexity of these instabilities implies an experimental validation of the theoretical models and their computer simulations. An experimental platform involving the Omega laser has allowed us to perform indirect drive with rugby-shaped hohlraums. The experiments have validated the growth of 2- and 3-dimensional initial defects as predicted by theory. We have shown that the 3-dimensional defect saturates for an higher amplitude than the 2-dimensional one does. The experiments have been made by using a plastic shell doped with Germanium (CH:Ge). (A.C.)

Predicting Urban Medical Services Demand in China: An Improved Grey Markov Chain Model by Taylor Approximation.

Science.gov (United States)

Duan, Jinli; Jiao, Feng; Zhang, Qishan; Lin, Zhibin

2017-08-06

The sharp increase of the aging population has raised the pressure on the current limited medical resources in China. To better allocate resources, a more accurate prediction on medical service demand is very urgently needed. This study aims to improve the prediction on medical services demand in China. To achieve this aim, the study combines Taylor Approximation into the Grey Markov Chain model, and develops a new model named Taylor-Markov Chain GM (1,1) (T-MCGM (1,1)). The new model has been tested by adopting the historical data, which includes the medical service on treatment of diabetes, heart disease, and cerebrovascular disease from 1997 to 2015 in China. The model provides a predication on medical service demand of these three types of disease up to 2022. The results reveal an enormous growth of urban medical service demand in the future. The findings provide practical implications for the Health Administrative Department to allocate medical resources, and help hospitals to manage investments on medical facilities.

The feed-out process: Rayleigh-Taylor and Richtmyer-Meshkov instabilities in thin, laser-driven foils

Energy Technology Data Exchange (ETDEWEB)

Smitherman, D.P.

1998-04-01

Eight beams carrying a shaped pulse from the NOVA laser were focused into a hohlraum with a total energy of about 25 kJ. A planar foil was placed on the side of the hohlraum with perturbations facing away from the hohlraum. All perturbations were 4 {micro}m in amplitude and 50 {micro}m in wavelength. Three foils of pure aluminum were shot with thicknesses and pulse lengths respectively of 86 {micro}m and 2. 2 ns, 50 {micro}m and 4.5 ns, and 35 {micro}m with both 2.2 ns and 4. 5 ns pulses. Two composite foils constructed respectively of 32 and 84 {micro}m aluminum on the ablative side and 10 {micro}m beryllium on the cold surface were also shot using the 2.2 ns pulse. X-ray framing cameras recorded perturbation growth using both face- and side-on radiography. The LASNEX code was used to model the experiments. A shock wave interacted with the perturbation on the cold surface generating growth from a Richtmyer-Meshkov instability and a strong acoustic mode. The cold surface perturbation fed-out to the Rayleigh-Taylor unstable ablation surface, both by differential acceleration and interface coupling, where it grew. A density jump did not appear to have a large effect on feed-out from interface coupling. The Rayleigh-Taylor instability`s vortex pairs overtook and reversed the direction of flow of the Richtmyer-Meshkov vortices, resulting in the foil moving from a sinuous to a bubble and spike configuration. The Rayleigh-Taylor instability may have acted as an ablative instability on the hot surface, and as a classical instability on the cold surface, on which grew second and third order harmonics.

Generalized Slavnov-Taylor, BRST and covariance identities from the geometry of the gauge surface. (corrigendum)

International Nuclear Information System (INIS)

Jarvis, P.D.; Thompson, G.

1987-04-01

We establish the equivalence between the extended BRST invariances, and the conventional Slavnov-Taylor transformations together with a new ''dual'' analogue. However, the latter (a non-local gauge transformation, generating an A-dependent translation of the gauge-fixing surface) is not an invariance of the Faddeev-Popov determinant, contrary to the published claim. (author)

NON-DETECTION OF L-BAND LINE EMISSION FROM THE EXOPLANET HD189733b

International Nuclear Information System (INIS)

Mandell, Avi M.; Deming, L. Drake; Mumma, Michael J.; Villanueva, Geronimo L.; Blake, Geoffrey A.; Knutson, Heather A.; Salyk, Colette

2011-01-01

We attempt to confirm bright non-local thermodynamic equilibrium (non-LTE) emission from the exoplanet HD 189733b at 3.25 μm, as recently reported by Swain et al. based on observations at low spectral resolving power (λ/δλ ∼ 30). Non-LTE emission lines from gas in an exoplanet atmosphere will not be significantly broadened by collisions, so the measured emission intensity per resolution element must be substantially brighter when observed at high spectral resolving power. We observed the planet before, during, and after a secondary eclipse event at a resolving power λ/δλ = 27, 000 using the NIRSPEC spectrometer on the Keck II telescope. Our spectra cover a spectral window near the peak found by Swain et al., and we compare emission cases that could account for the magnitude and wavelength dependence of the Swain et al. result with our final spectral residuals. To model the expected line emission, we use a general non-equilibrium formulation to synthesize emission features from all plausible molecules that emit in this spectral region. In every case, we detect no line emission to a high degree of confidence. After considering possible explanations for the Swain et al. results and the disparity with our own data, we conclude that an astrophysical source for the putative non-LTE emission is unlikely. We note that the wavelength dependence of the signal seen by Swain et al. closely matches the 2ν 2 band of water vapor at 300 K, and we suggest that an imperfect correction for telluric water is the source of the feature claimed by Swain et al.

Alfred Russel Wallace (1823-1913): the forgotten co-founder of the Neo-Darwinian theory of biological evolution.

Science.gov (United States)

Kutschera, Ulrich; Hossfeld, Uwe

2013-12-01

The British naturalist Alfred Russel Wallace (1823-1913), who had to leave school aged 14 and never attended university, did extensive fieldwork, first in the Amazon River basin (1848-1852) and then in Southeast Asia (1854-1862). Based on this experience, and after reading the corresponding scientific literature, Wallace postulated that species were not created, but are modified descendants of pre-existing varieties (Sarawak Law paper, 1855). Evolution is brought about by a struggle for existence via natural selection, which results in the adaptation of those individuals in variable populations who survive and reproduce (Ternate essay, 1858). In his monograph Darwinism (1889), and in subsequent publications, Wallace extended the contents of Darwin's Origin of Species (1859) into the Neo-Darwinian theory of biological evolution, with reference to the work of August Weismann (1834-1914). Wallace also became the (co)-founder of biogeography, biodiversity research, astrobiology and evolutionary anthropology. Moreover, he envisioned what was later called the anthropocene (i.e., the age of human environmental destructiveness). However, since Wallace believed in atheistic spiritualism and mixed up scientific facts and supernatural speculations in some of his writings, he remains a controversial figure in the history of biology.

Pramana – Journal of Physics | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Pramana – Journal of Physics. ABHAYA KUMAR SWAIN. Articles written in Pramana – Journal of Physics. Volume 89 Issue 4 October 2017 pp 56 Special Issue. Mass restricting variables in semi-invisible production at the LHC · PARTHA KONAR ABHAYA KUMAR SWAIN · More Details Abstract Fulltext ...

Rayleigh-Taylor and Kelvin-Helmholtz instabilities in targets accelerated by laser ablation

International Nuclear Information System (INIS)

Emery, M.H.; Gardner, J.H.; Boris, J.P.

1982-01-01

With use of the fast2d laser-shell model, the acceleration of a 20-μm-thick plastic foil up to 160 km/s has been simulated. It is possible to follow the Rayleigh-Taylor bubble-and-spike development far into the nonlinear regime and beyond the point of foil fragmentation. Strong shear flow develops which evolves into the Kelvin-Helmholtz instability. The Kelvin-Helmholtz instability causes the tips of the spikes to widen and as a result reduce their rate of ''fall.''

Collisional Rayleigh-Taylor instability and shear-flow in equatorial Spread-F plasma

Directory of Open Access Journals (Sweden)

N. Chakrabarti

2003-05-01

Full Text Available Collisional Rayleigh-Taylor (RT instability is considered in the bottom side of the equatorial F-region. By a novel nonmodal calculation it is shown that for an applied shear flow in equilibrium, the growth of the instability is considerably reduced. Finite but small amounts of diffusion enhances the stabilization process. The results may be relevant to the observations of long-lived irregularities at the bottom-side of the F-layer.Key words. Ionosphere (ionospheric irregularities, equatorial ionosphere, plasma waves and instabilities

Size invariance of the granular Rayleigh-Taylor instability.

Science.gov (United States)

Vinningland, Jan Ludvig; Johnsen, Øistein; Flekkøy, Eirik G; Toussaint, Renaud; Måløy, Knut Jørgen

2010-04-01

The size scaling behavior of the granular Rayleigh-Taylor instability [J. L. Vinningland, Phys. Rev. Lett. 99, 048001 (2007)] is investigated experimentally, numerically, and theoretically. An upper layer of grains displaces a lower gap of air by organizing into dense fingers of falling grains separated by rising bubbles of air. The dependence of these structures on the system and grain sizes is investigated. A spatial measurement of the finger structures is obtained by the Fourier power spectrum of the wave number k. As the size of the grains increases the wave number decreases accordingly which leaves the dimensionless product of wave number and grain diameter, dk, invariant. A theoretical interpretation of the invariance, based on the scaling properties of the model equations, suggests a gradual breakdown of the invariance for grains smaller than approximately 70 microm or greater than approximately 570 microm in diameter.

Torque balance, Taylor's constraint and torsional oscillations in a numerical model of the geodynamo

Science.gov (United States)

Dumberry, Mathieu; Bloxham, Jeremy

2003-11-01

Theoretical considerations and observations suggest that, to a first approximation, the Earth's dynamo is in a quasi-Taylor state, where the axial Lorentz torque on cylindrical surfaces co-axial with the rotation axis vanishes, except for the part involved in torsional oscillations. The latter are rigid azimuthal accelerations of cylindrical surfaces which oscillate with typical periods of decades. We present a solution of a numerical model of the geodynamo in which rigid accelerations of cylinder surfaces are observed. The underlying dynamic state in the model is not a Taylor state because the Reynolds stresses and viscous torque remain large and provide an effective way to balance a large Lorentz torque. This is a consequence of the limited parameter regime which can be attained numerically. Nevertheless, departures in the torque equilibrium are primarily counterbalanced by rigid accelerations of cylindrical surfaces, which, in turn, excite rigid azimuthal oscillations of the surfaces. We show that the azimuthal motion is indeed quasi-rigid, though the torsional oscillations that are produced in the model probably differ from those in the Earth's core because of the large influence of the Reynolds stresses on their dynamics. We also show that the continual excitation of rigid cylindrical accelerations is produced by the advection of the non-axisymmetric structure of the fields by a mean differential rotation of the cylindrical surfaces which produces disconnections and reconnections and continual fluctuations in the Lorentz torque and Reynolds stresses. We propose that the torque balance in Earth's core may evolve in a similar chaotic fashion, except that the influence of the Reynolds stresses is probably weaker. If this is the case, the Lorentz torque on a cylindrical surface is continually fluctuating, even though its time-averaged value vanishes and satisfies Taylor's constraint. Rigid accelerations of cylindrical surfaces are continually excited by the

Un punto de partida. Los trabajos de Paul S.Taylor sobre la migración mexicana a Estados Unidos

Directory of Open Access Journals (Sweden)

Jorge Durand

2000-01-01

Full Text Available Este artículo ofrece una mirada a los trabajos de Paul S. Taylor, principalmente, pero también se hace referencia a la labor de uno de los epígonos del investigador estadunidense, Manuel Gamio, con quien tuvo alguna relación. Ambos son referencia obligada para todos aquellos que estén interesados en el tema de la migración de mexicanos a Estados Unidos. Sin grandes teorías, Taylor dio cuenta de un fenómeno social complejo y dinámico mediante la interpretación y el análisis de sus propios datos, y este recurso metodológico quizá sea lo más sorprendente de sus análisis.

Evidence for a bubble-competition regime in indirectly driven ablative Rayleigh-Taylor instability experiments on the NIF.

Science.gov (United States)

Martinez, D A; Smalyuk, V A; Kane, J O; Casner, A; Liberatore, S; Masse, L P

2015-05-29

We investigate on the National Ignition Facility the ablative Rayleigh-Taylor instability in the transition from weakly nonlinear to highly nonlinear regimes. A planar plastic package with preimposed two-dimensional broadband modulations is accelerated for up to 12 ns by the x-ray drive of a gas-filled Au radiation cavity with a radiative temperature plateau at 175 eV. This extended tailored drive allows a distance traveled in excess of 1 mm for a 130  μm thick foil. Measurements of the modulation optical density performed by x-ray radiography show that a bubble-merger regime for the Rayleigh-Taylor instability at an ablation front is achieved for the first time in indirect drive. The mutimode modulation amplitudes are in the nonlinear regime, grow beyond the Haan multimode saturation level, evolve toward the longer wavelengths, and show insensitivity to the initial conditions.

An Instability in Stratified Taylor-Couette Flow

Science.gov (United States)

Swinney, Harry

2015-11-01

In the late 1950s Russell Donnelly began conducting experiments at the University of Chicago on flow between concentric rotating cylinders, and his experiments together with complementary theory by his collaborator S. Chandrasekhar did much to rekindle interest in the flow instability discovered and studied by G.I. Taylor (1923). The present study concerns an instability in a concentric cylinder system containing a fluid with an axial density gradient. In 2005 Dubrulle et al. suggested that a `stratorotational instability' (SRI) in this system could provide insight into instability and angular momentum transport in astrophysical accretion disks. In 2007 the stratorotational instability was observed in experiments by Le Bars and Le Gal. We have conducted an experiment on the SRI in a concentric cylinder system (radius ratio η = 0 . 876) with buoyancy frequency N / 2 π = 0.25, 0.50, or 0.75 Hz. For N = 0.75 Hz we observe the SRI onset to occur for Ωouter /Ωinner > η , contrary to the prediction of Shalybkov and Rüdiger. Research conducted with Bruce Rodenborn and Ruy Ibanez.

Processo de trabalho e eficiência produtiva: Smith, Marx, Taylor e Lênin

Directory of Open Access Journals (Sweden)

Benedito Rodrigues de Moraes Neto

2009-09-01

Full Text Available A partir de reflexão sobre uma hipotética transição do capitalismo em sua natureza manufatureira ao socialismo, procura-se deixar marcada a razão pela qual, seguindo a proposta de Marx, essa transição exige que a produção se realize sob a égide da maquinaria. Consegue-se, como parte dessa reflexão, identificar, para o caso da manufatura, um trade-off entre eficiência produtiva e humanização das atividades de trabalho. Procura-se esclarecer que, dada a natureza do taylorismo-fordismo como "reinvenção da manufatura", o exercício de início especulativo passa a ter sentido histórico. Busca-se argumentar que a ampla assimilação do taylorismo-fordismo pela experiência de implantação do socialismo na União Soviética a aprisionou ao mencionado trade-off , fazendo com que a primeira experiência de superação do capitalismo se impregnasse perversamente da mediocridade imanente ao taylorismo-fordismo. Finalmente, são feitos rápidos comentários acerca dos desdobramentos da recente automação de base microeletrônica sobre a natureza de um projeto socialista.From an analysis of a hypothetical transition from manufacture capitalism to socialism, we intend to stress the reason why, according to Marx´s proposition, it is demanded that this transition takes place under machinery´s domain. In the case of manufacture it is possible to identify a trade-off between the productive efficiency and the humanization of the labor activities. We then intend to clarify that the initially hypothetical speculation acquires a historic sense in as much as taylorism-fordism´s nature can be understood as a "reinvention of the manufacturing system". We shall then argue that the wide assimilation of taylorism-fordism in the Soviet Union´s experience of socialism implementation imprisoned it within the mentioned trade-off, which caused the first experience of capitalism´s surmount to be perversely impregnated with the immanent mediocrity of