Topological Constant-Intensity Waves

2022 ◽  
Author(s):  
Nicholas Ossi ◽  
Sathyanarayanan Chandramouli ◽  
Ziad Musslimani ◽  
Konstantinos Makris
Keyword(s):  
Author(s):  
J. M. Zuo ◽  
A. L. Weickenmeier ◽  
R. Holmestad ◽  
J. C. H. Spence

The application of high order reflections in a weak diffraction condition off the zone axis center, including those in high order laue zones (HOLZ), holds great promise for structure determination using convergent beam electron diffraction (CBED). It is believed that in this case the intensities of high order reflections are kinematic or two-beam like. Hence, the measured intensity can be related to the structure factor amplitude. Then the standard procedure of structure determination in crystallography may be used for solving unknown structures. The dynamic effect on HOLZ line position and intensity in a strongly diffracting zone axis is well known. In a weak diffraction condition, the HOLZ line position may be approximated by the kinematic position, however, it is not clear whether this is also true for HOLZ intensities. The HOLZ lines, as they appear in CBED patterns, do show strong intensity variations along the line especially near the crossing of two lines, rather than constant intensity along the Bragg condition as predicted by kinematic or two beam theory.


Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1291
Author(s):  
Abram I. Livashvili ◽  
Victor V. Krishtop ◽  
Polina V. Vinogradova ◽  
Yuriy M. Karpets ◽  
Vyacheslav G. Efremenko ◽  
...  

In this study, the nonlinear dynamics of nanoparticle concentration in a colloidal suspension (nanofluid) were theoretically studied under the action of a light field with constant intensity by considering concentration convection. The heat and nanoparticle transfer processes that occur in this case are associated with the phenomenon of thermal diffusion, which is considered to be positive in our work. Two exact analytical solutions of a nonlinear Burgers-Huxley-type equation were derived and investigated, one of which was presented in the form of a solitary concentration wave. These solutions were derived considering the dependence of the coefficients of thermal conductivity, viscosity, and absorption of radiation on the nanoparticle concentration in the nanofluid. Furthermore, an expression was obtained for the solitary wave velocity, which depends on the absorption coefficient and intensity of the light wave. Numerical estimates of the concentration wave velocity for a specific nanofluid—water/silver—are given. The results of this study can be useful in the creation of next-generation solar collectors.


2015 ◽  
Vol 23 (1) ◽  
Author(s):  
A. Montori ◽  
M. De Pas ◽  
M. Giuntini ◽  
M. Siciliani De Cumis ◽  
S. Viciani ◽  
...  

Abstract We describe an all−in−fibre apparatus for Constant Intensity Direct Absorption Spectroscopy (CIDAS) for gas concentration measurements which keeps the power of a diode laser constant along the frequency sweep. The reduction of the large variation of the laser power, connected to the frequency scan, enhances the ability of detecting small variations in a background signal, resulting in an increase of the sensitivity with respect to standard direct absorption techniques. Moreover, CIDAS allows for a real−time observation of the absorption signals without any kind of post−detection processing. The apparatus has been tested with carbon dioxide (CO


1979 ◽  
Vol 16 (4) ◽  
pp. 881-889 ◽  
Author(s):  
Hans Dieter Unkelbach

A road traffic model with restricted passing, formulated by Newell (1966), is described by conditional cluster point processes and analytically handled by generating functionals of point processes.The traffic distributions in either space or time are in equilibrium, if the fast cars form a Poisson process with constant intensity combined with Poisson-distributed queues behind the slow cars (Brill (1971)). It is shown that this state of equilibrium is stable, which means that this state will be reached asymptotically for general initial traffic distributions. Furthermore the queues behind the slow cars dissolve asymptotically like independent Poisson processes with diminishing rate, also independent of the process of non-queuing cars. To get these results limit theorems for conditional cluster point processes are formulated.


2018 ◽  
Vol 43 (4) ◽  
pp. 397-402 ◽  
Author(s):  
Corinne N. Boyd ◽  
Stephanie M. Lannan ◽  
Micah N. Zuhl ◽  
Ricardo Mora-Rodriguez ◽  
Rachael K. Nelson

While hot yoga has gained enormous popularity in recent years, owing in part to increased environmental challenge associated with exercise in the heat, it is not clear whether hot yoga is more vigorous than thermo-neutral yoga. Therefore, the aim of this study was to determine objective and subjective measures of exercise intensity during constant intensity yoga in a hot and thermo-neutral environment. Using a randomized, crossover design, 14 participants completed 2 identical ∼20-min yoga sessions in a hot (35.3 ± 0.8 °C; humidity: 20.5% ± 1.4%) and thermo-neutral (22.1 ± 0.2 °C; humidity: 27.8% ± 1.6%) environment. Oxygen consumption and heart rate (HR) were recorded as objective measures (percentage of maximal oxygen consumption and percentage of maximal HR (%HRmax)) and rating of perceived exertion (RPE) was recorded as a subjective measure of exercise intensity. There was no difference in exercise intensity based on percentage of maximal oxygen consumption during hot versus thermo-neutral yoga (30.9% ± 2.3% vs. 30.5% ± 1.8%, p = 0.68). However, exercise intensity was significantly higher during hot versus thermo-neutral yoga based on %HRmax (67.0% ± 2.3% vs. 60.8% ± 1.9%, p = 0.01) and RPE (12 ± 1 vs. 11 ± 1, p = 0.04). According to established exercise intensities, hot yoga was classified as light-intensity exercise based on percentage of maximal oxygen consumption but moderate-intensity exercise based on %HRmax and RPE while thermo-neutral yoga was classified as light-intensity exercise based on percentage of maximal oxygen uptake, %HRmax, and RPE. Despite the added hemodynamic stress and perception that yoga is more strenuous in a hot environment, we observed similar oxygen consumption during hot versus thermo-neutral yoga, classifying both exercise modalities as light-intensity exercise.


2020 ◽  
Vol 23 (4) ◽  
pp. 161-168
Author(s):  
Sergei A. Nikolsky ◽  

To reveal the theme of Russia after October, 1917, Nickolai Ostrovsky's book «How steel was tempered» is one of the most significant. In it, in its purest form, there is a portrait of an ideal revolutionary – a Bolshevik, merciless not only to the enemy, but to himself and others as well, a man, from whom, according to the poet's figurative expression, there could be made the strongest nails in the world. The book was enthusiastically received by the thirteen million army of party members and Komsomol members. For some, Pavel Korchagin was an ideal to emulate, for others – an image that reinforced their own myths about past heroic deeds, allowing them to settle warmly in the present. For the authorities, the story, cleared by censorship from the Bolshevik democracy of the first years, was an artistic forerunner of the future Stalinist «Short course of the AUCP history». One of the most thoughtful Soviet literary critics, Leo Anninsky, considered the story to be a story about people «engaged to an idea». In a sense, this is true. However, the engagement prevented both Ostrovsky and his Soviet interpreter from seeing the real historical process in its tragic depth and contradictions. For the hero Pavel Korchagin, there are neither the beginnings of Stalinist totalitarianism, nor the tragedy of a collectivized, starving village. Living as if out of time, he preaches the same thing – a class struggle that never fades for a moment. It seems that the fire of struggle will be extinguished and the hero's life will be interrupted. In fact, this is not allowed to happen: the constant intensity of the class struggle, which, as Stalin said, will grow more and more as we move towards socialism, is the secret of Soviet totalitarianism, represented and justified in an artistic form by Nikolai Ostrovsky.


2008 ◽  
Vol 40 (04) ◽  
pp. 919-938 ◽  
Author(s):  
Kasra Alishahi ◽  
Mohsen Sharifitabar

This paper is devoted to the study of some asymptotic behaviors of Poisson-Voronoi tessellation in the Euclidean space as the space dimension tends to ∞. We consider a family of homogeneous Poisson-Voronoi tessellations with constant intensity λ in Euclidean spaces of dimensions n = 1, 2, 3, …. First we use the Blaschke-Petkantschin formula to prove that the variance of the volume of the typical cell tends to 0 exponentially in dimension. It is also shown that the volume of intersection of the typical cell with the co-centered ball of volume u converges in distribution to the constant λ−1(1 − e−λu ). Next we consider the linear contact distribution function of the Poisson-Voronoi tessellation and compute the limit when the space dimension goes to ∞. As a by-product, the chord length distribution and the geometric covariogram of the typical cell are obtained in the limit.


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