Cleaning with Laser Radiation on Istria Stone

1992 ◽  
Vol 267 ◽  
Author(s):  
Pagona Maravelaki ◽  
G. Biscontin ◽  
E. Zendri ◽  
R. Polloni ◽  
W. Cecchetti
Keyword(s):  
Laser Radiation ◽  
Laser Treatment ◽  
Chemical Processes ◽  
Original Material ◽  
Stone Surface ◽  
Stone Conservation ◽  
Physico Chemical

ABSTRACTCleaning treatments necessary for stone conservation consist of removing compounds that were superimposed on the original material by means of physico-chemical processes.,The purpose of this work is to identify the transformation of stone surface by the LASER treatment. Cleaning test on Istria stone with LASER radiation at different energies and in different regimes have been performed. The depletion of the original material has been evaluated by means of SEM microprobe analyses.

Nucleophilicity and its parametrization

1989 ◽  
Vol 54 (1) ◽  
pp. 117-135
Author(s):  
Oldřich Pytela ◽  
Vítězslav Zima
Keyword(s):  
Regression Analysis ◽  
Linear Correlation ◽  
Correlation Equation ◽  
Chemical Processes ◽  
General Tendency ◽  
Orbital Interaction ◽  
Physico Chemical ◽  
Physical And Chemical ◽  
Two Parameter ◽  
Better Than

The method of conjugate deviations based on the regression analysis has been suggested for construction of a new nucleophilicity scale. This method has been applied to a set of 28 nucleophiles participating in 47 physical and chemical processes described in literature. The two-parameter nucleophilicity scale obtained represents-in the parameter denoted as ND-the general tendency to form a bond to an electrophile predominantly on the basis of the orbital interaction and-in the parameter denoted as PD-the ability to interact with a centre similar to the proton (basicity). The linear correlation equation involving the ND, PD parameters and the charge appears to be distinctly better than the most significant relations used. The correlation dependences have the physico-chemical meaning. From the position of individual nucleophiles in the space of the ND and PD parameters, some general conclusions have been derived about the factors governing the reactivity of nucleophiles.

Enzymes at solid surfaces: Nature of the interfaces and physico-chemical processes

2008 ◽  
Vol 54 (1) ◽  
pp. 116-122 ◽  
Author(s):  
Samuel Caillou ◽  
Patrick A. Gerin ◽  
Cristèle J. Nonckreman ◽  
Sandrine Fleith ◽  
Christine C. Dupont-Gillain ◽  
...  
Keyword(s):  
Chemical Processes ◽  
Solid Surfaces ◽  
Physico Chemical

scholarly journals X-ray and UV Radiation Damage of dsDNA/Protein Complexes

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3132
Author(s):  
Paweł Wityk ◽  
Dorota Kostrzewa-Nowak ◽  
Beata Krawczyk ◽  
Michał Michalik ◽  
Robert Nowak
Keyword(s):  
Dna Damage ◽  
Simple Model ◽  
Uv Radiation ◽  
Protein Complexes ◽  
Chemical Processes ◽  
Model Systems ◽  
Degradation Pathways ◽  
X Ray ◽  
Physico Chemical ◽  
Sensitization Process

Radiation and photodynamic therapies are used for cancer treatment by targeting DNA. However, efficiency is limited due to physico-chemical processes and the insensitivity of native nucleobases to damage. Thus, incorporation of radio- and photosensitizers into these therapies should increase both efficacy and the yield of DNA damage. To date, studies of sensitization processes have been performed on simple model systems, e.g., buffered solutions of dsDNA or sensitizers alone. To fully understand the sensitization processes and to be able to develop new efficient sensitizers in the future, well established model systems are necessary. In the cell environment, DNA tightly interacts with proteins and incorporating this interaction is necessary to fully understand the DNA sensitization process. In this work, we used dsDNA/protein complexes labeled with photo- and radiosensitizers and investigated degradation pathways using LC-MS and HPLC after X-ray or UV radiation.

Computational Exploration of Functional Nanoscale Carbonaceous Materials

2021 ◽  
Vol 17 ◽  
Author(s):  
Grigoriy Sereda ◽  
Md Tusar Uddin ◽  
Jacob Wente
Keyword(s):  
Biomedical Applications ◽  
Chemical Processes ◽  
Computational Power ◽  
Carbonaceous Materials ◽  
New Materials ◽  
New Era ◽  
Physico Chemical ◽  
Computational Exploration ◽  
Properties Of Materials ◽  
Computational Research

Background: The unique ability of carbon to form a wide variety of allotrope modifications has ushered a new era in the material science. Tuning the properties of these materials by functionalization is a must-have tool for their design customized for a specific practical use. The exponentially growing computational power available to researchers allows for the prediction and thorough understanding of the underlying physico-chemical processes responsible for the practical properties of pristine and modified carbons using the methods of quantum chemistry. Method: This review focuses on the computational assessment of the influence of functionalization on the properties of carbons and enabling desired practical properties of the new materials. The first section of each part of this review focuses on graphene - nearly planar units built from sp2-carbons. The second section discusses patterns of sp2-carbons rolled-up into curved 3D-structures in a variety of ways (fullerenes). The overview of other types of carbonaceous materials including those with a high abundance of sp3-carbons, including nanodiamonds, can be found in the third section of each manuscript’s part. Conclusion: The computational methods are especially critical for predicting electronic properties of materials such as the band gap, conductivity, optical and photoelectronic properties, solubility, adsorptivity, potential for catalysis, sensing, imaging and biomedical applications. We expect that introduction of defects to carbonaceous materials as a type of their functionalization will be a point of growth in this area of computational research.

scholarly journals Physico-Chemical Processes

2017 ◽  
Vol 89 (10) ◽  
pp. 974-1028 ◽  
Author(s):  
Bin Hua ◽  
Huixin Xiong ◽  
Mohammed Kadhom ◽  
Lei Wang ◽  
Guocheng Zhu ◽  
...  
Keyword(s):  
Chemical Processes ◽  
Physico Chemical

Biological and physico-chemical processes in excrements of soil animals

Geoderma ◽  
1993 ◽  
Vol 56 (1-4) ◽  
pp. 331-347 ◽  
Author(s):  
A. Martin ◽  
J.C.Y. Marinissen
Keyword(s):  
Chemical Processes ◽  
Soil Animals ◽  
Physico Chemical

scholarly journals Recovery of Cerium from Glass Polishing Waste: A Critical Review

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 801 ◽  
Author(s):  
Chenna Borra ◽  
Thijs Vlugt ◽  
Yongxiang Yang ◽  
S. Offerman
Keyword(s):  
Particle Size ◽  
Chemical Properties ◽  
Value Added ◽  
Leach Solution ◽  
Chemical Processes ◽  
Efficient Utilization ◽  
Selective Precipitation ◽  
Physico Chemical ◽  
Main Component ◽  
Glass Polishing

Ceria is the main component in glass polishing powders due to its special physico-chemical properties. Glass polishing powder loses its polishing ability gradually during usage due to the accumulation of other compounds on the polishing powder or due to changes in the particle size distribution. The recovery of cerium from the glass polishing waste results in the efficient utilization of natural resources. This paper reviews processes for the recovery of rare earths from polishing waste. Glass polishing powder waste can be reused via physical, physico-chemical or chemical processes by removing silica and/or alumina. The removal of silica and/or alumina only improves the life span up to some extent. Therefore, removal of other elements by chemical processes is required to recover a cerium or cerium-rich product. However, cerium leaching from the polishing waste is challenging due to the difficulties associated with the dissolution of ceria. Therefore, high acid concentrations, high temperatures or costly reducing agents are required for cerium dissolution. After leaching, cerium can be extracted from the leach solution by solvent extraction or selective precipitation. The product can be used either in glass polishing again or other high value added applications.

scholarly journals Modification of gas-thermal coatings surface by continuous-generation laser radiation

2018 ◽  
Vol 226 ◽  
pp. 01015
Author(s):  
Evgeniy A. Chaschin ◽  
Konstantin I. Kurganov ◽  
Andrey A. Mitrofanov ◽  
Andrey H. Kharakhashev ◽  
Mikhail M. Klimov
Keyword(s):  
Image Processing ◽  
Laser Radiation ◽  
Laser Treatment ◽  
Quantitative Assessment ◽  
Ceramic Coating ◽  
Initial Position ◽  
Average Porosity ◽  
Processing Program ◽  
Continuous Generation ◽  
Thermal Coating

The results of the researches which determine the dependence of gas-thermal coating porosity on the laser radiation parameters are given in the article. The coatings which are based on the metallic (PN-85-U-15) and non-metallic (Al2O3) components were analyzed. The quantitative assessment of porosity modification were realized by means of the based on Visual Studio 2008 program. This image processing program allows to compare the microstructure of the occupied by pores and coating material areas pixel-by-pixel. It has been established that the action of laser radiation leads to reduction of average porosity of gas-thermal coating. This reduction is: 1. the porosity in the initial position for coating of a PN 85-U-15-based alloy is 17%; after the laser treatment it’s 5-8%; 2.- the porosity in the initial position for ceramic coating of Al2O3is 24,5%; after the laser treatment it’s 15-18%.

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