scholarly journals Fluid dynamic instabilities: theory and application to pattern forming in complex media

2017 ◽  
Vol 375 (2093) ◽  
pp. 20160155 ◽  
Author(s):  
François Gallaire ◽  
P.-T. Brun
Keyword(s):  
Stability Analysis ◽  
Pattern Formation ◽  
Fluid Dynamic ◽  
Fluid Flows ◽  
Review Article ◽  
Media Theory ◽  
Complex Media ◽  
Theoretical Methods ◽  
Pattern Forming ◽  
Potential Use

In this review article, we exemplify the use of stability analysis tools to rationalize pattern formation in complex media. Specifically, we focus on fluid flows, and show how the destabilization of their interface sets the blueprint of the patterns they eventually form. We review the potential use and limitations of the theoretical methods at the end, in terms of their applications to practical settings, e.g. as guidelines to design and fabricate structures while harnessing instabilities. This article is part of the themed issue ‘Patterning through instabilities in complex media: theory and applications’.

scholarly journals Recent Advancements in the Understanding of the Surface Chemistry in TiO2 Photocatalysis

Surfaces ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 72-92 ◽  
Author(s):  
Alexander V. Vorontsov ◽  
Héctor Valdés ◽  
Panagiotis G. Smirniotis ◽  
Yaron Paz
Keyword(s):  
Surface Chemistry ◽  
Surface Science ◽  
Oxygen Vacancies ◽  
Anatase Phase ◽  
Review Article ◽  
Theoretical Research ◽  
Synthesis Methods ◽  
Theoretical Methods ◽  
Structure Of Nanoparticles ◽  
Nanoscale Level

Surface chemistry plays a major role in photocatalytic and photoelectrochemical processes taking place with the participation of TiO2. The synthesis methods, surface characterizations, theoretical research methods, and hardware over the last decade generated opportunities for progress in the surface science of this photocatalyst. Very recently, attention was paid to the design of photocatalysts at the nanoscale level by adjusting the types of exposed surfaces and their ratio, the composition and the surface structure of nanoparticles, and that of individual surfaces. The current theoretical methods provide highly detailed designs that can be embodied experimentally. The present review article describes the progress in the surface science of TiO2 and TiO2-based photocatalysts obtained over the last three years. Such aspects including the properties of macro- and nano-scale surfaces, noble-metal-loaded surfaces, doping with Mg and S, intrinsic defects (oxygen vacancies), adsorption, and photoreactions are considered. The main focus of the article is on the anatase phase of TiO2.

Development of phthalocyanines for photodynamic therapy

2006 ◽  
Vol 10 (09) ◽  
pp. 1116-1124 ◽  
Author(s):  
Shun-ichiro Ogura ◽  
Kenji Tabata ◽  
Kaoru Fukushima ◽  
Toshiaki Kamachi ◽  
Ichiro Okura
Keyword(s):  
Photodynamic Therapy ◽  
Review Article ◽  
Synthetic Activity ◽  
Potential Use

Photodynamic therapy is a method for treating several diseases, most notably cancer. Recent synthetic activity has created a number of phthalocyanines for potential use as photodynamic therapy photosensitizers. In this mini-review article, the background and the concepts in the development of new phthalocyanines are introduced.

scholarly journals Regimes of wrinkling in pressurized elastic shells

2017 ◽  
Vol 375 (2093) ◽  
pp. 20160330 ◽  
Author(s):  
Matteo Taffetani ◽  
Dominic Vella
Keyword(s):  
Finite Element ◽  
Stability Analysis ◽  
Detailed Analysis ◽  
Indentation Depth ◽  
Elastic Shell ◽  
Analytical Techniques ◽  
Finite Element Simulations ◽  
Media Theory ◽  
Threshold Analysis ◽  
Elastic Shells

We consider the point indentation of a pressurized elastic shell. It has previously been shown that such a shell is subject to a wrinkling instability as the indentation depth is quasi-statically increased. Here we present detailed analysis of this wrinkling instability using a combination of analytical techniques and finite-element simulations. In particular, we study how the number of wrinkles observed at the onset of instability grows with increasing pressurization. We also study how, for fixed pressurization, the number of wrinkles changes both spatially and with increasing indentation depth beyond onset. This ‘Far from threshold’ analysis exploits the largeness of the wrinkle wavenumber that is observed at high pressurization and leads to quantitative differences with the standard ‘Near threshold’ stability analysis. This article is part of the themed issue ‘Patterning through instabilities in complex media: theory and applications.’

Improvements in Lightly Loaded Rotor/Bearing and Rotor/Seal Models

1988 ◽  
Vol 110 (2) ◽  
pp. 129-136 ◽  
Author(s):  
A. Muszynska
Keyword(s):  
Stability Analysis ◽  
Fluid Dynamic ◽  
Velocity Ratio ◽  
Nonlinear Function ◽  
Circumferential Velocity ◽  
Rotating Shaft ◽  
Model Adequacy ◽  
Dynamic Forces ◽  
Key Factor ◽  
Lateral Mode

A model for lightly loaded steadily rotating shaft/bearing/seal systems is proposed in this paper. The model is based on modal characteristics for the rotor, and rotational characteristics for the fluid dynamic forces generated in bearings and/or seals. The fluid average circumferential velocity ratio as a nonlinear function of shaft eccentricity represents a key factor in the model. The model is extremely useful for rotor stability analysis. The model adequacy was proved for one and two lateral mode models of rotors.

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