scholarly journals A Kinetic Description of How Interfaces Accelerate Reactions in Micro-Compartments

Author(s):  
Kevin Wilson ◽  
Alexander Prophet ◽  
Grazia Rovelli ◽  
Megan Willis ◽  
Rebecca Rapf ◽  
...  

A kinetic expression is derived to explain how interfaces alter bulk chemical equilibria and accelerate reactions in micro-compartments. This description, aided by the development of a stochastic model, quantitatively predicts previous experimental observations of accelerated imine synthesis in micron-sized emulsions.

2020 ◽  
Author(s):  
Kevin Wilson ◽  
Alexander Prophet ◽  
Grazia Rovelli ◽  
Megan Willis ◽  
Rebecca Rapf ◽  
...  

A kinetic expression is derived to explain how interfaces alter bulk chemical equilibria and accelerate reactions in micro-compartments. This description, aided by the development of a stochastic model, quantitatively predicts previous experimental observations of accelerated imine synthesis in micron-sized emulsions.


Author(s):  
Randall W. Smith ◽  
John Dash

The structure of the air-water interface forms a boundary layer that involves biological ,chemical geological and physical processes in its formation. Freshwater and sea surface microlayers form at the air-water interface and include a diverse assemblage of organic matter, detritus, microorganisms, plankton and heavy metals. The sampling of microlayers and the examination of components is presently a significant area of study because of the input of anthropogenic materials and their accumulation at the air-water interface. The neustonic organisms present in this environment may be sensitive to the toxic components of these inputs. Hardy reports that over 20 different methods have been developed for sampling of microlayers, primarily for bulk chemical analysis. We report here the examination of microlayer films for the documentation of structure and composition.Baier and Gucinski reported the use of Langmuir-Blogett films obtained on germanium prisms for infrared spectroscopic analysis (IR-ATR) of components. The sampling of microlayers has been done by collecting fi1ms on glass plates and teflon drums, We found that microlayers could be collected on 11 mm glass cover slips by pulling a Langmuir-Blogett film from a surface microlayer. Comparative collections were made on methylcel1ulose filter pads. The films could be air-dried or preserved in Lugol's Iodine Several slicks or surface films were sampled in September, 1987 in Chesapeake Bay, Maryland and in August, 1988 in Sequim Bay, Washington, For glass coverslips the films were air-dried, mounted on SEM pegs, ringed with colloidal silver, and sputter coated with Au-Pd, The Langmuir-Blogett film technique maintained the structure of the microlayer intact for examination, SEM observation and EDS analysis were then used to determine organisms and relative concentrations of heavy metals, using a Link AN 10000 EDS system with an ISI SS40 SEM unit. Typical heavy microlayer films are shown in Figure 3.


Author(s):  
Arezki Tagnit-Hamou ◽  
Shondeep L. Sarkar

All the desired properties of cement primarily depend on the physicochemical characteristics of clinker from which the cement is produced. The mineralogical composition of the clinker forms the most important parameter influencing these properties.Optical microscopy provides reasonably accurate information pertaining to the thermal history of the clinker, while XRDA still remains the proven method of phase identification, and bulk chemical composition of the clinker can be readily obtained from XRFA. Nevertheless, all these microanalytical techniques are somewhat limited in their applications, and SEM/EDXA combination fills this gap uniquely by virtue of its high resolution imaging capability and possibility of instantaneous chemical analysis of individual phases.Inhomogeneities and impurities in the raw meal, influence of kiln conditions such as sintering and cooling rate being directly related to the microstructure can be effectively determined by SEM/EDXA. In addition, several physical characteristics of cement, such as rhcology, grindability and hydraulicity also depend on the clinker microstructure.


1964 ◽  
Vol 9 (7) ◽  
pp. 273-276
Author(s):  
ANATOL RAPOPORT
Keyword(s):  

1996 ◽  
Vol 6 (4) ◽  
pp. 445-453 ◽  
Author(s):  
Roberta Donato
Keyword(s):  

1987 ◽  
Vol 26 (03) ◽  
pp. 117-123
Author(s):  
P. Tautu ◽  
G. Wagner

SummaryA continuous parameter, stationary Gaussian process is introduced as a first approach to the probabilistic representation of the phenotype inheritance process. With some specific assumptions about the components of the covariance function, it may describe the temporal behaviour of the “cancer-proneness phenotype” (CPF) as a quantitative continuous trait. Upcrossing a fixed level (“threshold”) u and reaching level zero are the extremes of the Gaussian process considered; it is assumed that they might be interpreted as the transformation of CPF into a “neoplastic disease phenotype” or as the non-proneness to cancer, respectively.


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