Search Results - (Author, Cooperation:R. Tanner)

2014-10-04

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Animals ; Enzyme Inhibitors/*pharmacology ; Humans ; Jumonji Domain-Containing Histone Demethylases/*antagonists & inhibitors ; Macrophages/*drug effects/*immunology

2012-07-31

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Amino Acid Sequence ; Animals ; Biocatalysis/drug effects ; Catalytic Domain ; Cells, Cultured ; Enzyme Inhibitors/metabolism/*pharmacology ; Evolution, Molecular ; Histones/chemistry/metabolism ; Humans ; Inhibitory Concentration 50 ; Jumonji Domain-Containing Histone Demethylases/*antagonists & ; inhibitors/chemistry/classification/metabolism ; Lysine/metabolism ; Macrophages/*drug effects/enzymology/*immunology/metabolism ; Methylation/drug effects ; Mice ; Models, Molecular ; Substrate Specificity ; Tumor Necrosis Factor-alpha/biosynthesis

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] THE Microscopical Society of London, now the Royal Microscopical Society, was founded in 1839, and it was proposed to celebrate its centenary this October with a special meeting. This function has been postponed for the present, but papers on the progress of microscopy during the last hundred ...

Electronic Resource

0142-2421

Chemistry ; Polymer and Materials Science

Wiley InterScience Backfile Collection 1832-2000

Physics

The determination of pH value at a cathode surface requires the use of a technique capable of detecting the initial precipitation of a tracer ion. It is shown that XPS fulfils this role and that thicknesses of deposit may be estimated. The results can be correlated well with simple hydrodynamic theory and may be related to deposits formed on power station condenser tubes operating in sea water.

3 Ill.

Electronic Resource

1468-2265

Blackwell Publishing Journal Backfiles 1879-2005

Philosophy

Theology and Religious Studies

Electronic Resource

1468-2265

Blackwell Publishing Journal Backfiles 1879-2005

Philosophy

Theology and Religious Studies

Electronic Resource

1468-2265

Blackwell Publishing Journal Backfiles 1879-2005

Philosophy

Theology and Religious Studies

Electronic Resource

1468-2265

Blackwell Publishing Journal Backfiles 1879-2005

Philosophy

Theology and Religious Studies

Electronic Resource

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

A molecular dynamics simulation of a thin liquid film as it is sheared between two planar walls is reported. The model liquid is composed of linear chain molecules of hexadecane (C16H34) with intramolecular architecture such as bond stretching, angle bending and dihedral potentials included in the model. Designing a model that can mimic the planar shear flow enables us to study important questions on the effects of the wall properties on the slip between the liquid film and the wall. Different properties of the wall such as wall density, wall stiffness and wall–fluid interaction strength have been studied to determine the slip between the wall and fluid. The slip has been investigated for strong and weak adsorbing surfaces at various shear rates. The results emphasize the importance of adsorption on the degree of slip. The dependence of slip on the film thickness is also demonstrated. © 1999 American Institute of Physics.

Electronic Resource

1089-7666

AIP Digital Archive

Physics

A viscous jet is not usually observed to separate from a sharp edge in the manner expected theoretically. In the present paper the separation of a creeping jet emerging from a tube with a rounded exit is considered. As a separation criterion, in the absence of surface tension, we propose that the traction normal to the nozzle surface drops to zero at the separation point. Boundary-element calculations then show a behavior that agrees with experimental data and with previous finite-element computations. They also permit the Michael condition to be observed at separation, so that the discrepancy between finite-element calculations and theory is removed.

Electronic Resource

0026-7074

Classical Studies

0030-5383

Linguistics and Literary Studies

Ethnic Sciences

History

Besprechungen

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] The experiment has now been performed in Sydney, Australia. For this we should like to express appreciation for assistance from the University of Sydney, Tufts University, and the U.S. National Science Foundation. The apparatus was modelled on Shapiro's. It was a tank, 6 ft. in diameter and 9 in. ...

Electronic Resource

0007-0904

Art History

0004-8402

Philosophy

REVIEWS

0004-8402

Philosophy

REVIEWS

0004-8402

Philosophy

CRITICAL NOTICES

1435-1528

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Physics

Zusammenfassung Dieser Bericht behandelt eine Methode zur Messung der zweiten Normalspannungsdifferenz in einer viskoelastischen Strömung in einem offenen, halbkreisförmigen, geneigten Kanal. Die theoretische Behandlung des Problems ist ebenfalls angegeben und zeigt die einfachen Zusammenhänge auf, welche zwischen der zweiten Normalspannungsdifferenz, der Schubspannung und dem Profil (Wölbung) der freien Oberfläche der Strömung bestehen. Der Einfluß der Oberflächenspannung, in einer früheren Untersuchung vernachlässigt, ist jetzt berücksichtigt und in die mathematische Behandlung einbezogen worden. Polyisobutylen/Cetan, einige wäßrige Lösungen sowie eine Probe N.B.S. No. 1 wurden untersucht. Als Kanal gelangten zwei Röhren verschiedener Größe und aus verschiedenem Material bei veränderlicher Neigung zur Anwendung. Übereinstimmung der Resultate von verschiedenen Kanalgrößen und Neigungswinkeln zeigen, daß Theorie und Experiment im Einklang stehen. Die hier veröffentlichten Ergebnisse zeigen weiter, daß das Verhältnis der zweiten zur ersten Normalspannungsdifferenz negativ ist, und die funktionale Form der zweiten Normalspannungsdifferenz mit guter Näherung dem Quadrat der Schubspannung folgt. Relativ betrachtet ergibt sich für verdünnte Lösungen ein höherer Wert |N 2 /N 1|. Abschließend wird eine Übersicht über die verfügbaren Messungen vonN 2 an Polyisobutylen gegeben und vernünftige Übereinstimmung zwischen den Resultaten verschiedener Autoren festgestellt. Eine Darstellung vonN 2 als Funktion der Konzentration für verschiedene Polymerlösungen vervollständigt den Bericht.

Summary This paper deals with the measurement of the second normal stress difference in a viscoelastic flow in an open semi-circular inclined channel; associated theory is also given. The theory shows that simple correlations exist for the second normal stress difference, the shear stress, and the profile (or the deflection) of the free surface of the flow. It leads to a method for deducing the second normal stress from the measured surface profile. A treatment of surface tension, whose effect has been ignored in previous analyses is given as an integral part of the formulation. Samples of polyisobutylene/cetane and some aqueous solutions of different concentrations were used for measurements using two tubes of different materials and sizes tilted at different angles. The N.B.S. No. 1 nonlinear sample was also tested. Agreements between results for different tube sizes and angles indicate the consistency of the theory and measurements. The results presented here show that the ratio of the second to the first normal stress differences is negative and the functional form of the second normal stress difference is close to a square law in shear stress in the range investigated. Relatively speaking, we find the ratio |N 2 /N 1| to be greater for more dilute solutions. A summary of available data onN 2 is given for polyisobutylene, and reasonable consistency between various investigators is demonstrated for this material. Besides, a correlation ofN 2 for various polymer solutions is also shown.

Electronic Resource

1435-1528

Time-temperature superposition ; extrusion swell ; Péclet number

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Physics

Abstract A pseudo-time integral scheme based on a finite streamline element method is developed to combine variable temperature with viscoelasticity. A specific KBKZ integral model for isothermal flow is transformed to its non-isothermal version by introducing a pseudo-time and applying the Morland-Lee hypothesis. The coupling between momentum and energy equations is through the time-temperature shifting factor by which the pseudo-time is defined. The observer time and the pseudo-time are simultaneously calculated when tracing the strain history for the stress calculation in a non-homogeneous temperature field. Using this scheme, a full non-isothermal numerical simulation of some IUPAC extrusion experiments is carried out. Results show that while the temperature distribution near the die exit plane is an important factor controlling extrudate swell, either self-heating inside the die tube or external cooling on the free surface dominantly determines the temperature distribution near the die exit when the wall temperature is kept constant, depending on whether the Péclet number is large or small. The hot layer effect predicted by the inelastic swell mechanism is confirmed and well illustrated by the computation. Calculations with reasonable thermal boundary conditions further convince us that the isothermal assumption in our earlier numerical simulation is a good approximation in this particular case.

Electronic Resource

1435-1528

Separability ; irreversibility ; KBKZ model ; reversing step strains

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Physics

Abstract The hypotheses of separability and irreversibility, which have greatly improved the accuracy of constitutive models of the KBKZ type are tested in reversing step shear and elongational deformations. A reversing double-step deformation is a severe test for constitutive models and a new rheometer has been developed to perform this type of deformation, both in shear and elongation, in a single machine. Test results of a commercial low-density polyethylene melt are reported here with model predictions. In particular, the performance of the KBKZ-type integral model and a differential analogue is considered. Wagner's idea of irreversibility and the KBKZ-equivalent ideas of Larson are tested with these data. While these versions show a moderate agreement with experiment, the irreversible integral model gives an accurate fit and emerges clearly as the best description of polymer melts in these flows.

Electronic Resource