Inelastic collision processes of low-energy protons in liquid water

Production probabilities of ions and excited particle species along the proton beam track in liquid water are estimated around the Bragg peak region, taking into account charge-changing processes and energetic secondary electron (δ-ray) behavior. Ionization and excitation processes are divided into two categories in this study: primary processes associated with direct proton (or hydrogen) interaction and secondary processes arising from the electrons ejected by the primary process. We show that the number of events in the secondary processes producing ions and excited particles is larger than that of the primary processes around the Bragg peak while neutralized protons (i.e., hydrogen) with low energy have a large contribution to direct ionization. Effects of charge-changing processes on ionization and excitation are also discussed.     

Electron attachment processes in halomethanes

We have investigated thermal electron capture processes in the mixtures of halomethanes and carbon dioxide (in excess) using the electron swarm method. We have found that except the very slow second order reactions (single collision) there occur processes involving homo-(RX)₂ or heterogeniouos (RX·CO₂) van der Waals complexes (multi-body pressure dependent processes) which are at least a few times faster at atmospheric pressures. The mechanism and the kinetics of some of these processes are presented.     

Recent advances in electrochemical water technologies for the treatment of antibiotics: A short review

This short review presents a critical overview of the most recent works published in the literature related to the use of electrochemical advanced oxidation processes (EAOPs) for the treatment of antibiotics present in synthetic and real wastewaters. The first section focuses on novelties within the traditional EAOPs, including electrochemical oxidation and electrochemical Fenton-based processes. The second section is devoted to new electrochemical technologies, including heterogeneous electro-Fenton, electrochemically activated persulfate processes, and combined processes. Future perspectives about these processes are also presented to aid the continuous evolution of research in the area.     

Analysis of the efficiency of liquid membranes in extraction processes

Calculations were made to study the processes of purification of substances in a series of extraction and stripping columns or in a battery of mixer-settlers using a combination of free and supported liquid membranes. It was found that the efficiency of recovery or separation of substances in processes using liquid membranes exceeds that in conventional processes even after breaking up a series of columns or a battery of mixer-settlers into as few as two extractant-circulation loops. Investigation of the dependence of the purification processes on various parameters showed that the maximal effect on the processes is exerted by the distribution coefficients of substances at the stripping stage.     

Nuclear excitation in atomic processes

We have introduced a model of two indistinguishable quantum oscillators (IQO) and examined several processes of nuclear excitations in atomic transitions. These processes are: (i) nuclear excitation in an electron transition, (ii) radiationless transitions in muonic atoms, (iii) nuclear excitation in positron-electron annihilation, and (iv) inelastic photoelectric effect. Predictions of our IQO model for these processes are in very good agreement with the available experimental data.     

Study of conversion processes in multicomponent systems in manufacture of complex magnesium-containing fertilizers

Conversion processes occurring upon introduction of various kinds of magnesium-containing raw materials in separate technological stages of fabrication of complex NP fertilizers based on ammonium phosphates and NPK fertilizers produced by acid decomposition of phosphate raw materials were studied. It was found that there occur exchange interaction processes yielding double magnesium-ammonium sulfates, magnesium hydroand dihydrophosphates, and double magnesium-ammonium hydrophosphate. The involvement of magnesium chlorides in the conversion processes is confirmed by the formation of polyhalite.     

The special features of heat conversion into work in solar cell energy reemission

The absorption of radiant energy in solar cells is divided into parallel reversible and irreversible circular processes. Their fractions correlate with the known thermodynamic limits of the efficiency of heat conversion into work provided the conversion of solar energy is divided into antenna and work processes. (An analogue of antenna processes is the selective absorption of solar radiation by pigment molecules of plant cells, and an example of work processes is the work of chlorophyll molecules in plant photosynthesis.) It is shown that an efficiency of solar cells close to limiting cannot be achieved without reversible antenna processes.     

Quality planning in the ’in vitro diagnostic’ industry

In vitro diagnostic (IVD) manufacturers play an important role in helping to provide laboratory results that meet the needs of patient care. Industry, the primary source of new technologies, uses established processes to assure a continuous supply of products that satisfies health care needs. The processes include validation of user needs, with well-controlled procedures that are used to manufacture quality products. Management uses routine audits and customer complaint monitoring to identify improvement opportunities. The processes used in the IVD industry are recognized quality practices that should be, and often are, used in the clinical laboratory.     

Noncovalent associations in fluorous fluids

Perfluorocarbons (PFCs) are emerging as a new type of liquid phase in which molecular recognition processes can effectively take place. The combination of perfluorocarbons (PFCs) and noncovalent associations, mostly hydrogen bonds, ion pairing, halogen bonds or coordination bonds, has already been successfully exploited for applications in organic synthesis (catalyst recycling, by-product removal), electrochemical sensing, selective extraction/titration processes or to prepare gels. Due to the extreme solvophobic effect in PFCs, the least polar existing fluids, noncovalent associations tend to be enhanced. For instance, quantitative data on the increase in association strength occurring in PFCs have recently been reported for ion-pairing interactions or encapsulation processes. Moreover, several examples show that confining a receptor in a fluorous phase leads to recognition processes with improved selectivity.     

Mechanistic implications of the equality of compensation temperatures in chromatography

A common interpretation of the observation that two processes exhibit similar compensation temperatures in an enthalpy-entropy plot is that the two processes occur via the same "mechanism". We show that this interpretation is not rigorously allowed. In fact, the only thing that can be concluded from the observation of identical compensation temperatures is that the relative contributions of enthalpy and entropy to the overall free energy are the same in the two processes. Since it is possible that two processes occur via different mechanisms that, by chance, result in the same relative blends of enthalpy and entropy, the observation of identical compensation temperatures cannot be used as evidence for mechanistic identity. If two processes exhibit different compensation temperatures, however, it can logically be concluded that the two processes are mechanistically distinct.     

Photophysical processes and the photodissociation of chemical bonds in polyatomic molecules

The main concepts of the nature of electronically excited states in polyatomic molecules and the intramolecular and intermolecular processes of their evolution are reported. The dependence of the probabilities of these processes on the electronic structure of the molecule is considered. Possible mechanisms of the dissociation of electronically excited molecules with bond cleavage are discussed, and the theoretical results of this consideration are given. The experimental data obtained by the authors are interpreted. In this case, attention is focused on C-H-bond photodissociation processes in a condensed phase, which are the best studied processes. The dissociation of other bonds is briefly discussed.     

Erosion processes in anthropogenic systems in the South of the Russian Far East

The results of studying erosion processes in anthropogenic systems in the South of the Russian Far East are given. The surface of tailings dumps has been shown to be subjected to not only air and wind but also chemical erosion, which creates a great hazard to the environment and human health. A direct relation has been found between the anthropogenic material discharge and precipitation amount. Its maximal value during intense erosion processes has been estimated. A set of measures has been proposed to reduce the impact of erosion processes in mining anthropogenic systems.     

Spin-lattice relaxation in biopolymeric sorbents in the presence of water

The effects of water on relaxation processes in polysaccharides were investigated by the NMR, adsorption, and comparative methods. It was shown that the relaxation vitrification transition that occurred in polysaccharides during the formation of an adsorption layer about two water molecules thick made the largest contribution to the spin-relaxation processes in the polymer-water system.     

Trend in using TiO2 nanotubes as photoelectrodes in PEC processes for wastewater treatment

Photoelectrocatalytic (PEC) processes represent an effective way to exploit renewable energy in response to the sustainable development objectives. The synergy between photo and electrochemical processes inspired several papers and stimulated research toward new systems that could be increasingly adapted to work under visible or solar radiation, and with minimum bias potential. Since the first appearance of articles on PEC processes in the literature, titanium dioxide has been one of the most studied semiconductor materials: nanostructured electrodes have been especially considered such as nanotubes (NT), which are the main subject of the present article. The software VOSviewer is used to a preliminary analysis of metadata, related to the trend of the research on PEC processes; attention is then paid on the trend of NT-TiO₂ electrodes for application in wastewater treatment in the past year.     

Elimination of spin diffusion effects in saturation transfer experiments: application to hydrogen exchange in proteins

The NMR saturation transfer experiment is widely used to characterize exchange processes in proteins that take place on the ms-s timescale. However, spin diffusion effects are inherently associated with the saturation transfer experiment and may overshadow the effect of the exchange processes of interest. As shown here, the effects from spin diffusion and exchange processes can be separated by varying the field strength of the saturation pulse, thereby allowing correct exchange rates to be obtained. The method is demonstrated using the hydrogen exchange process in the protein Escherichia coli thioredoxin as an example.     

Multinanoparticle Translocations in Phospholipid Membranes:Translocation Modes and Dynamic Processes

Multinanoparticles interacting with the phospholipid membranes in solution were studied by dissipative particle dynamics simulation. The selected nanoparticles have spherical or cylindrical shapes, and they have various initial velocities in the dynamical processes. Several translocation modes are defined according to their characteristics in the dynamical processes, in which the phase diagrams are constructed based on the interaction strengths between the particles and membranes and the initial velocities of particles. Furthermore, several parameters, such as the system energy and radius of gyration, are investigated in the dynamical processes for the various translocation modes. Results elucidate the effects of multiparticles interacting with the membranes in the biological processes.     

Correlation and compatibility in multivariate data analysis

Eigenvectors reflect active processes (real principal components or factors). The concepts of inherent compatibility and global compatibility are introduced. The inherent compatibility coefficient is used to study individual processes, whereas the global compatibility coefficient is used to study the combined nature and effect of each of the processes. The inherent and global variable compatibility of triterpanes is derived from a data base of 216 oil samples, and important pathways of the formation of oil from sedimentary kerogen are elucidated. The inefficiency of conventional data analysis is demonstrated.     

Time resolved laser spectroscopy of excited state processes in photoinduced polymerization reactions

During the last years, the use of photoinduced radical chain polymerization of unsatured monomers has increased considerably because of the vide applications of these processes in photoactive polymer-based systems. The present paper is mainly concerned with an investigation of the processes involved. For this purpose, time resolved laser spectroscopy (which appears to be a very convenient method for investigating directly the experimental behaviour of selectively excited chromophores) has been used. The utility of such a technique for the investigation of the primary processes which occur in the excited states of the photoinitiators immediately after the absorption of photons is demonstrated. As examples, main outlines corresponding to the classical processes observed in radical photoinitiated polymerization are considered and discussed: excited state processes in photoinitiators; mechanism of excitation transfer in combination of photosensitive systems; visible laser light induced polymerization; holographic recording.     

Supramolecular click procedures in liquid crystals

ABSTRACT

Click reactions have been introduced as highly reliable chemical processes, in which even complex molecular building blocks can be connected irreversibly by covalent bonds. Although reversible processes like supramolecular aggregation controlled by specific interactions like hydrogen bonding or metal complexation are also highly reliable and omnipresent in nature, they are rarely considered as click reactions. Mechanical processes in daily life associated with a click procedure depending only on shape recognition and space-filling are snap fasteners, snap fit buckels and ball detents and they are almost unknown in the nanoworld. This account defines such processes on a molecular basis and highlights some recent examples of star-shaped, shape-persistent mesogens designed to control the nanostructure of columnar liquid crystals for future photovoltaic applications. The click procedure leading to these structures is compared to related systems like the CPI and the LC shuttlecock.     

False multiple exciton recombination and multiple exciton generation signals in semiconductor quantum dots arise from surface charge trapping

Multiple exciton recombination (MER) and multiple exciton generation (MEG) are two of the main processes for assessing the usefulness of quantum dots (QDs) in photovoltaic devices. Recent experiments, however, have shown that a firm understanding of both processes is far from well established. By performing surface-dependent measurements on colloidal CdSe QDs, we find that surface-induced charge trapping processes lead to false MER and MEG signals resulting in an inaccurate measurement of these processes. Our results show that surface-induced processes create a significant contribution to the observed discrepancies in both MER and MEG experiments. Spectral signatures in the transient absorption signals reveal the physical origin of these false signals.