How Physical and Chemical Information Predicts the Action of Molecules: A Historical Overview

2021 ◽  
pp. 97-116
Author(s):  
Myron L. Toews ◽  
JoEllyn M. McMillan ◽  
David B. Bylund
Keyword(s):  
Chemical Information ◽  
Historical Overview ◽  
Physical And Chemical

scholarly journals Potential of spectroscopic analyses for non-destructive estimation of tea quality-related metabolites in fresh new leaves

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hiroto Yamashita ◽  
Rei Sonobe ◽  
Yuhei Hirono ◽  
Akio Morita ◽  
Takashi Ikka
Keyword(s):  
Short Wave ◽  
Machine Learning Algorithms ◽  
Estimation Methods ◽  
Chemical Information ◽  
Tea Quality ◽  
The Mean ◽  
Processing Techniques ◽  
Spectral Patterns ◽  
Physical And Chemical ◽  
Non Destructive

AbstractSpectroscopic sensing provides physical and chemical information in a non-destructive and rapid manner. To develop non-destructive estimation methods of tea quality-related metabolites in fresh leaves, we estimated the contents of free amino acids, catechins, and caffeine in fresh tea leaves using visible to short-wave infrared hyperspectral reflectance data and machine learning algorithms. We acquired these data from approximately 200 new leaves with various status and then constructed the regression model in the combination of six spectral patterns with pre-processing and five algorithms. In most phenotypes, the combination of de-trending pre-processing and Cubist algorithms was robustly selected as the best combination in each round over 100 repetitions that were evaluated based on the ratio of performance to deviation (RPD) values. The mean RPD values were ranged from 1.1 to 2.7 and most of them were above the acceptable or accurate threshold (RPD = 1.4 or 2.0, respectively). Data-based sensitivity analysis identified the important hyperspectral regions around 1500 and 2000 nm. Present spectroscopic approaches indicate that most tea quality-related metabolites can be estimated non-destructively, and pre-processing techniques help to improve its accuracy.

The Application of 57FE Mössbauer Spectroscopy to the Characterization of Nuclear Waste Forms

1981 ◽  
Vol 6 ◽  
Author(s):  
Paul G. Huray ◽  
M. T. Spaar ◽  
S. E. Nave ◽  
J. M. Legan ◽  
L. A. Boatner ◽  
...  
Keyword(s):  
Nuclear Waste ◽  
Chemical Properties ◽  
Electronic Charge ◽  
Chemical Information ◽  
Waste Forms ◽  
Charge States ◽  
Physical And Chemical ◽  
Nuclear Waste Forms

The electronic charge states and site symmetries of the radioactive ions incorporated in nuclear waste forms are of considerable importance in determining the physical and chemical properties of these materials. An in situ characterization of these ions is, unfortunately, often difficult – especially when a mixture of charge states and local crystal symmetries exist. The application of Mbssbauer spectroscopy represents a powerful technique for obtaining solid state chemical information.

Nanostructured sensors for molecular recognition

1995 ◽  
Vol 353 (1703) ◽  
pp. 333-354 ◽  
Keyword(s):  
Molecular Recognition ◽  
Chemical Sensors ◽  
Surface Structures ◽  
Chemical Information ◽  
New Materials ◽  
Top Down ◽  
Molecular Scale ◽  
The Common ◽  
Nanostructured Sensors ◽  
Physical And Chemical

A survey is given on typical ‘top-down’ and ‘bottom-up’ approaches to design nanostructured sensors which monitor different physical and chemical quantities. Particular emphasis is put on new materials and transducers for molecular recognition by chemical sensors. These convert chemical information into electronic signals by making use of suitable ‘key-lock’ structures. This requires the control of surface structures of chemically sensitive materials down to the molecular scale under thermodynamically or kinetically controlled conditions. This in turn requires the molecular understanding of sensor mechanisms which is deduced from comparative microscopic, spectroscopic and sensor test studies on ‘prototype materials’. Selected case studies illustrate the common mechanisms of molecular recognition with electron conductors, ion conductors, mixed conductors, molecular cages, polymers and selected biomolecular function units.

scholarly journals DEVELOPMENT OF REACTION-RECTIFICATION PROCESS OF OBTAINING MESITYL OXIDE. I. SIMULATION OF KINETICS AND PHASE EQUILIBRIUM IN THE REACTION SYSTEM

2018 ◽  
Vol 13 (5) ◽  
pp. 5-13 ◽  
Author(s):  
M. A. Yakhyaev ◽  
V. S. Gutenkov ◽  
Yu. A. Pisarenko
Keyword(s):  
Phase Equilibrium ◽  
Chemical Transformation ◽  
Equilibrium Model ◽  
Equilibrium Constants ◽  
Reaction System ◽  
Mesityl Oxide ◽  
Chemical Information ◽  
Thermochemical Parameters ◽  
Physical And Chemical ◽  
Rectification Process

Mesityl oxide is an important product of organic synthesis, which is used in the manufacture of pharmaceuticals and as a solvent. The demand for mesityl oxide is growing, which determines the need for further improvement of its production. The disadvantages of the traditional methods of obtaining mesityl oxide are low values of reagent conversion and selectivity. To eliminate them, it is proposed to obtain mesityl oxide in a combined reaction-rectification process. The combination of chemical transformation and separation of the resulting reaction mixture by means of rectification in one apparatus allows for a continuous withdrawal of the formed products from the reaction zone, which increases the rate of the target reaction, conversion and selectivity. In accordance with the modern strategy for the development of chemical-technological processes, the collection and processing of physical and chemical information on the properties of the components and mixtures contained in the reaction system was performed. Based on the experimental data, the parameters of the phase equilibrium model are determined, and its adequacy is estimated. The phase equilibrium model was used to construct a distillation diagram, to verify its consistency, and to conduct computational studies of the reaction-rectification process. The thermochemical parameters of the target reactions are calculated, the equilibrium constants are determined, and their temperature dependence is established. On the basis of the analysis of the literature data, a kinetic model of the process is proposed, and the conditions favorable for the course of the desired chemical transformation are determined with the use of this model. The obtained data are necessary for carrying out the analysis of the statics, constructing the basic technological scheme and calculating its static parameters.

Artificial intelligence for discrimination of sediment facies based on high-resolution elemental and colour data from coastal sediments of the East Frisian Wadden Sea, Germany

2020 ◽  
Author(s):  
An-Sheng Lee ◽  
Dirk Enters ◽  
Sofia Ya Hsuan Liou ◽  
Bernd Zolitschka
Keyword(s):  
Machine Learning ◽  
High Resolution ◽  
Wadden Sea ◽  
Environmental Variability ◽  
Conventional Approach ◽  
Coastal Sediments ◽  
Supervised Machine Learning ◽  
Chemical Information ◽  
Xrf Core Scanner ◽  
Physical And Chemical

<p>Sediment facies provide vital information for the reconstruction of past environmental variability. Due to rising interest for paleoclimate data, sediment surveys are continually growing in importance as well as the amount of sediments to be discriminated into different facies. The conventional approach is to macroscopically determine sediment structure and colour and combine them with physical and chemical information - a time-consuming task heavily relying on the experience of the scientist in charge. Today, rapidly generated and high-resolution multiproxy sediment parameters are readily available from down-core scanning techniques and provide qualitative or even quantitative physical and chemical sediment properties. In 2016, an interdisciplinary research project WASA (Wadden Sea Archive) was launched to investigate palaeo-landscapes and environments of the Wadden Sea. The project has recovered 92 up to 5 m long sediment cores from the tidal flats, channels and off-shore around the island of Norderney (East Frisian Wadden Sea, Germany). Their facies were described by the conventional approach into glacioflucial sands, moraine, peat, tidal deposits, shoreface sediments, etc. In this study, those sediments were scanned by a micro X-ray fluorescence (µ-XRF) core scanner to obtain high-resolution records of multi-elemental data (2000 µm) and optical images (47 µm). Here we propose a supervised machine-learning application for the discrimination of sediment facies using these scanning data. Thus, the invested time and the potential bias common for the conventional approach can be reduced considerably. We expect that our approach will contribute to developing a more comprehensive and time-efficient automatic sediment facies discrimination.</p><p>Keywords: the Wadden Sea, µ-XRF core scanning, machine-learning, sediment facies discrimination</p>

Colloquium 2004: Hydrogeotechnical properties of hard rock tailings from metal mines and emerging geoenvironmental disposal approaches

2007 ◽  
Vol 44 (9) ◽  
pp. 1019-1052 ◽  
Author(s):  
Bruno Bussière
Keyword(s):  
Chemical Stability ◽  
Current Practice ◽  
Hard Rock ◽  
Environmental Risks ◽  
Historical Overview ◽  
Metal Mines ◽  
Tailings Management ◽  
Management Approaches ◽  
Physical And Chemical ◽  
Hard Rock Mines

Tailings are ground rock particles from which the valuable minerals or metals have been extracted. An historical overview on hard rock mines shows that since the 1930s, it has become current practice to pump the tailings into storage areas circumscribed by dykes made of the tailings themselves. However, numerous physical and chemical stability problems were observed mainly owing to the particular hydrogeotechnical and mineralogical properties of the tailings. Therefore, modifications to the conventional methods were proposed, but these were relatively costly, not always efficient, and sometimes difficult to implement. New management methods that improve the physical and (or) chemical stability have hence been developed to reduce environmental risks associated with tailings storage, namely, densified tailings, environmental desulphurization, covers built with tailings, and co-disposal of tailings and waste rock. Even if many aspects need to be optimized, these approaches can be considered today as interesting alternatives to conventional tailings management approaches.

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