Picosecond molecular relaxations: the role of the fluid in electron solvation

1977 ◽  
Vol 55 (11) ◽  
pp. 2009-2016 ◽  
Author(s):  
G. A. Kenney-Wallace
Keyword(s):  
Experimental Data ◽  
Room Temperature ◽  
Fluid Layer ◽  
Liquid Structure ◽  
Polar Fluid ◽  
Electron Solvation ◽  
Orientational Polarization ◽  
Excess Electrons ◽  
Electron Migration

The role of the fluid is considered for a model of electron solvation in liquid alcohols. The events that lead to trapping and solvation of excess electrons are reconstructed from experimental data on the time and frequency-dependent electron absorptions (kmol) and the appropriate molecular rotational relaxations (τ2, τc), local liquid structure, viscosity (η), and orientational polarization (β) of the supporting fluid. The quasifree electron is captured at subpicosecond times in a preexisting trap in the liquid, which in alcohols is identified as an alcohol cluster whose local configurational fluctuations will be frozen in on this timescale. Rapid configurational relaxation of the cluster molecules, including multi-phonon processes, then occurs in the field of the excess electron at times ≤10−12 s. Finally, the molecules in the fluid layer adjacent to the initial trapping site align in the now screened field of the localized electron in a manner comparable to solvation of an ion embedded in a polar fluid. The relaxation may occur in competition with electron migration and reaction. The observed rate constant of the final step kmol is shown to be proportional to βη−1 for a range of alcohols at room temperature. The implications of this model for photobleaching experiments in liquids are briefly discussed.

scholarly journals Role of Sawdust in the Removal of Iron from Aqueous Solution

2017 ◽  
Vol 23 (3) ◽  
pp. 223 ◽  
Author(s):  
H.B. Senin ◽  
O. Subhi ◽  
R. Rosliza ◽  
N. Kancono ◽  
M.S. Azhar ◽  
...  
Keyword(s):  
Experimental Data ◽  
Aqueous Solution ◽  
Langmuir Isotherm ◽  
Room Temperature ◽  
Freundlich Isotherm ◽  
Batch Test ◽  
Freundlich Isotherms ◽  
Langmuir And Freundlich Isotherms ◽  
Better Than

Sawdust, inexpensive material has been utilized as an absorbent for the removal of iron from aqueous solution for their safe disposal. The adsorption experiments of untreated sawdust (SD) and treated sawdust (SDC) have been carried out at room temperature using the batch test. The Langmuir and Freundlich isotherms were used to observe sorption phenomena of sawdust in the removal of iron. The results indicate that the sawdust was capable in removing iron in aqueous solution. The results have shown that the Langmuir isotherm was found well fitted into the experimental data as compared to the Freundlich isotherm. It was found that, chemisorptions and physisorption were the prime mechanism for the process of adsorption to occur between the sawdust and iron. The results also proved that the acid sulphuric treated sawdust is much better than that of untreated sawdust as an adsorbent for iron.

Optical absorption of Cu2O in the near infrared and the role of metallic inclusions

1980 ◽  
Vol 58 (3) ◽  
pp. 325-333 ◽  
Author(s):  
F. L. Weichman ◽  
J. M. Reyes
Keyword(s):  
Experimental Data ◽  
Optical Absorption ◽  
Scattering Theory ◽  
Room Temperature ◽  
Near Infrared ◽  
Copper Films ◽  
Nonspherical Particles ◽  
Metallic Inclusions ◽  
Absorption Characteristics

We have measured the optical absorption characteristics of copper oxide single crystals in the range from 1.1 to 2.0 eV. The crystals were annealed at various oxygen pressures at high temperatures and quenched to room temperature. A major, broad, previously unknown absorption peak was found at 1.6 eV which we relate to the formation of copper inclusions in the oxide. Although experimental data on thin copper films agree with our assumptions, we cannot reconcile our results with scattering theory of small metal spheres embedded in a dielectric. Agreement between scattering theory and optical absorption may be achieved for nonspherical particles for which as yet no other experimental evidence exists.

Fracture Mechanisms in SiC-Whisker Reinforced Alumina

1988 ◽  
Vol 120 ◽  
Author(s):  
Christophe H. Boulanger ◽  
Yih-Cherng Chiang ◽  
Azar P. Majidi ◽  
Tsu-Wei Chou
Keyword(s):  
Experimental Data ◽  
Fracture Toughness ◽  
Room Temperature ◽  
Crack Deflection ◽  
Fracture Mechanisms ◽  
Alumina Composite ◽  
Good Agreement

AbstractThe fracture mechanisms involved in the toughening of alumina by whisker reinforcement are studied at room temperature. The fracture toughness of a hot pressed SiC-whisker/alumina composite is measured and good agreement is found between the experimental data and a model that takes into account the effects of crack deflection and whisker pullout mechanisms. From the model, it is seen that the role of whisker pullout is negligible compared to that of crack deflection.

Evidence for ordered Fe3Ni

1987 ◽  
Vol 45 ◽  
pp. 216-217
Author(s):  
K.B. Reuter ◽  
D.B. Williams ◽  
J.I. Goldstein
Keyword(s):  
Experimental Data ◽  
Martensitic Transformation ◽  
Electron Diffraction ◽  
Room Temperature ◽  
Direct Evidence ◽  
Transformation Product ◽  
Iron Meteorites ◽  
X Ray ◽  
Ni Content ◽  
Temperature Transformation

In the Fe-Ni system, although ordered FeNi and ordered Ni3Fe are experimentally well established, direct evidence for ordered Fe3Ni is unconvincing. Little experimental data for Fe3Ni exists because diffusion is sluggish at temperatures below 400°C and because alloys containing less than 29 wt% Ni undergo a martensitic transformation at room temperature. Fe-Ni phases in iron meteorites were examined in this study because iron meteorites have cooled at slow rates of about 10°C/106 years, allowing phase transformations below 400°C to occur. One low temperature transformation product, called clear taenite 2 (CT2), was of particular interest because it contains less than 30 wtZ Ni and is not martensitic. Because CT2 is only a few microns in size, the structure and Ni content were determined through electron diffraction and x-ray microanalysis. A Philips EM400T operated at 120 kV, equipped with a Tracor Northern 2000 multichannel analyzer, was used.

Clustering-Triggered Efficient Room Temperature Phosphorescence from Nonconventional Luminophores

2019 ◽  
Author(s):  
Shuyuan Zheng ◽  
Taiping Hu ◽  
Xin Bin ◽  
Yunzhong Wang ◽  
Yuanping Yi ◽  
...  
Keyword(s):  
Room Temperature ◽  
High Efficiency ◽  
Spin Orbit Coupling ◽  
Design Rationale ◽  
Emission Mechanism ◽  
Room Temperature Phosphorescence ◽  
Electronic Interactions ◽  
Energy Gaps ◽  
Theoretical Results

Pure organic room temperature phosphorescence (RTP) and luminescence from nonconventional luminophores have gained increasing attention. However, it remains challenging to achieve efficient RTP from unorthodox luminophores, on account of the unsophisticated understanding of the emission mechanism. Here we propose a strategy to realize efficient RTP in nonconventional luminophores through incorporation of lone pairs together with clustering and effective electronic interactions. The former promotes spin-orbit coupling and boost the consequent intersystem crossing, whereas the latter narrows energy gaps and stabilizes the triplets, thus synergistically affording remarkable RTP. Experimental and theoretical results of urea and its derivatives verify the design rationale. Remarkably, RTP from thiourea solids with unprecedentedly high efficiency of up to 24.5% is obtained. Further control experiments testify the crucial role of through-space delocalization on the emission. These results would spur the future fabrication of nonconventional phosphors, and moreover should advance understanding of the underlying emission mechanism.<br>

РОЛЬ ФИЗИЧЕСКОЙ РАЗМИНКИ В ПОДГОТОВКЕ К ТРЕНИРОВОЧНЫМ ЗАНЯТИЯМ И СОРЕВНОВАНИЯМ ШАХМАТИСТОВ БГУ

2019 ◽  
pp. 63-65
Author(s):  
Судоргин Е.П. ◽  
Карсакова И.Н.
Keyword(s):  
Experimental Data ◽  
Sport Performance ◽  
Warm Up ◽  
Physical Exercises ◽  
Methods Of Evaluation ◽  
Mental Fitness ◽  
Physical Preparation ◽  
Tools And Methods

Аннотация: О роли разминки перед тренировкой и соревнованиями написано много научных статьей и диссертаций. Ещё больше о значимости физической подготовки спортсменов, в том числе и шахматистов. В то же время авторы считают, что вопросу физической подготовки шахматистов и в частности разминке в научной и научно-методической литературе уделяется недостаточно внимания. В своей статье авторы приводят собственные экспериментальные данные о влиянии физических упражнений (разминки) на умственную работоспособность студентов-шахматистов БГУ и как следствие на спортивные результаты команды. Ключевые слова: Шахматы, разминка, умственная работоспособность, средства и методы разминки, методы оценки результатов. Аннотация: Машыгуунун жана мелдештердин алдында даярдоонун ролу жөнүндө көптөгөн илимий макала жана диссертация жазылган. Ошондой эле илимий жана илимий-методикалык адабияттарда шахматка даярдоого көп көңүл бурулбай жатат. Макаланын авторлору шахмат ойногон студенттерге физикалык көнүгүүлөрдүн тийгизген таасири жөнүндө өздөрүнүн эксперименталдык маалыматтарын көргөзүштү. Түйүндүү сөздөр: Шахмат, акыл-дарамет, курулуштар жана ыкмалар, баа берүү жыйынтыгы боюнча кабыл алынат. Abstract: on the role of warm-up before training and competitions written many scientific articles and theses. More about the significance of the physical preparation of athletes, including players. At the same time, the authors believe that the issue of fit- ness players and in particular workout in scientific and scientific-methodical literature neglected. In his article the authors cite their own experimental data on the influence of physical exercises (warm-up) on the mental fitness of students-BSU players and as a result the sport performance team. Keywords: chess, warm-up, mental fitness, workout tools and methods, methods of evaluation results.

Sewage sludge as a precursor of adsorbents/catalysts for environmental applications

2007 ◽  
Vol 2 (1) ◽  
Author(s):  
A. Ros ◽  
C. Canals-Batlle ◽  
M.A. Lillo-Ródenas ◽  
E. Fuente ◽  
M. A. Montes-Morán ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Room Temperature ◽  
Waste Water Treatment ◽  
Textural Properties ◽  
Active Species ◽  
Elemental Sulphur ◽  
Gaseous Emissions ◽  
Removal Experiments ◽  
Catalytically Active

This paper focuses on the valorisation of solid residues obtained from the thermal treatment of sewage sludge. In particular, sewage sludge samples were collected from two waste water treatment plants (WWTPs) with different sludge line basic operations. After drying, sludges were heated up to 700 °C in appropriate ovens under diluted air (gasification) and inert (pyrolysis) atmospheres. The solids obtained, as well as the dried (raw) sludges, were characterised to determine their textural properties and chemical composition, including the speciation of their inorganic fraction. All the materials under study were employed as adsorbents/catalysts in H2S removal experiments at room temperature. It was found that, depending on the particular sludge characteristics, outstanding results can be achieved both in terms of retention capacities and selectivity. Some of the solids outperform commercially available sorbents specially designed for gaseous emissions control. In these adsorbents/catalysts, H2S is selectively oxidised to elemental sulphur most likely due to the presence of inorganic, catalytically active species. The role of the carbon-enriched part on these solids is also remarked.

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