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The risks of property losses caused by terrorist activities have not been isolated by insurers for a very long time. The situation has changed dramatically due to the events of September 11, 2001, which demonstrated the need to form a new approach to solving the problem of insurance coverage of damage caused by terrorist attacks. Accordingly, the purpose of this particular study was to determine the optimal model of insurance against terrorist risks. Therefore, several approaches, based on the analysis of Russian and foreign legislation, to solving this problem have been identified. At the same time, reinsurance has become a common mechanism aimed at protecting the interests of insurers, which in most cases is carried out with the participation of the state. However, state resources are formed for these purposes and are used in such cases in different ways. The targeted use of funds is ensured through the use of special funds, the funds of which in some states (France, Israel) are formed at the expense of targeted tax deductions. In addition, differences can be traced in the scope and procedure of State participation in covering the damage caused. In some countries (for example, in Belgium), this obligation arises only if the problem cannot be solved through a reinsurance system.

Rational synthesis and simple methodology for the purification of large (35-45 nm in lateral size) and flat (1.0-1.5 nm of height) nitrogen-doped graphene oxide quantum dots (GOQDs) are presented. The methodology allows robust metal-free and acid-free preparation of N-GOQDs with a yield of about 100% and includes hydrothermal treatment of graphene oxide with hydrogen peroxide and ammonia. It was demonstrated that macroscopic impurities can be separated from N-GOQD suspension by their coagulation with 0.9% NaCl solution. Redispersible in water and saline solutions, particles of N-GOQDs were characterized using tip-enhanced Raman spectroscopy (TERS), photoluminescent, XPS, and UV-VIS spectroscopies. The size and morphology of N-GOQDs were studied by dynamic light scattering, AFM, SEM, and TEM. The procedure proposed allows nitrogen-doped GOQDs to be obtained, having 60-51% of carbon, 34-45% of oxygen, and up to 7.2% of nitrogen. The N-GOQD particles obtained in two hours of synthesis contain only pyrrolic defects of the graphene core. The fraction of pyridine moieties grows with the time of synthesis, while the fraction of quaternary nitrogen declines. Application of TERS allows demonstration that the N-GOQDs consist of a graphene core with an average crystallite size of 9 nm and an average distance between nearest defects smaller than 3 nm. The cytotoxicity tests reveal high viability of the monkey epithelial kidney cells Vero in the presence of N-GOQDs in a concentration below 60 mg L

This paper presents a recently developed variant of phase-resolved Optical Coherence Elastography (OCE) enabling non-contact visualization of transient local strains of various origins in biological tissues and other materials. In this work, we demonstrate the possibilities of this new technique for studying dynamics of osmotically-induced strains in cartilaginous tissue impregnated with optical clearing agents (OCA). For poroelastic water-containing biological tissues, application of non-isotonic OCAs, various contrast additives, as well as drug solutions administration, may excite transient spatially-inhomogeneous strain fields of high magnitude in the tissue bulk, initiating mechanical and structural alterations. The range of the strain reliably observed by OCE varied from ±10−3 to ±0.4 for diluted and pure glycerol, correspondingly. The OCE-technique used made it possible to reveal previously inaccessible details of the complex spatio-temporal evolution of alternating-sign osmotic strains at the initial stages of agent diffusion. Qualitatively different effects produced by particular hydrophilic OCAs, such as glycerol and iohexol, are discussed, as well as concentration-dependent differences. Overall, the work demonstrates the unique abilities of the new OCE-modality in providing a deeper insight in real-time kinetics of osmotically-induced strains relevant to a broad range of biomedical applications.

The purpose of this work is to perform numerical simulation of particle motion in a cylindrical drum of a grain separator based on solving three-dimensional systems of force analysis and determining the influence of the main acting factors. The research methodology included the force analysis of particles motion along the inner cylindrical part of the rotating drum of the grain separator on the basis of three-dimensional force analysis system, determining the conditions of particles falling out of the cells and determining the trajectory of the flight. As a result of mathematical modelling, the influence of structural, kinematic and technological factors on the angle of rise of particles not included in the cell, the angle of beginning of particle exit from the cell and the trajectory of particle flight was established. The main factor influencing the violation of the nature of particle flow is the coefficient of friction, which is determined by both the type of plant (seed parameters) and its moisture content. An increase in moisture content leads to an increase in the friction coefficient and an additional rise of the granulate. This causes wheat grains to enter the short impurity fraction or oat seeds to enter the cleaned wheat grain fraction, which causes malfunctioning of the grain separator.

Here we present the first example of excitation-independent blue-emitting carbon dots (iC-dots) obtained by pyrolysis of citric acid (CA) without post-treatment chromatographic separation. To confi...

A method of dispersive liquid-liquid microextraction (DLLME) with gas chromatographic separation has been developed and applied for the determination of phthalate esters in water samples and liquid pharmaceuticals. The method allows the determination of various phthalate esters with different polarities, namely: dimethyl phthalate, diethyl phthalate, di-iso-butyl phthalate, di-n-butyl phthalate, di(2-ethylhexyl) phthalate and di-n-octyl phthalate, with high values for the enrichment factors (370–390) and extraction recoveries (91–97%). Almost complete isolation of the phthalate esters from water samples was achieved by DLLME using chloroform as the extracting phase containing a minimum of 5–10% acetonitrile, isopropanol, or acetone as the disperser solvent and 10% sodium chloride as the salting-out agent. The results showed that increasing the amount of disperser solvent in the extracting phase leads to the growth in the phase polarity and thus improves the extractability of the polar analytes. The limits of detection determined for a signal-to-noise ratio equal to 3 were in the range from 1.0 to 1.6 µg L−1 and the relative standard deviations for 10.0 µg L−1 were below 9.7% (n = 3). The developed method demonstrates good repeatability and linearity and will be useful for the screening and quantitative determination of phthalate esters in various water samples and liquid pharmaceuticals.

Titania (TiO

In bone surgery and orthopedics, bioresorbable materials can be helpful in bone repair and countering post-op infections. Explicit antibacterial activity, osteoinductive and osteoconductive effects are essential to achieving this objective. Nonwoven electrospun (ES) fibers are receiving the close attention of physicians as promising materials for wound dressing and tissue engineering, potentially, in high contrast with dense materials, ES mats hamper regeneration of the bone extracellular matrix to a lesser extent. The use of the compositions of inherently biodegradable polyesters (poly(ε-caprolactone) PCL, poly(lactoglycolide), etc.), calcium phosphates and antibiotics is highly prospective, but the task of forming ES fibers from such compositions is complicated by the incompatibility of the main organic and inorganic ingredients, polyesters and calcium phosphates. In the present research we report the synthesis of hydroxyapatite (HAp) nanoparticles with uniform morphology, and demonstrate high efficiency of the block copolymer of PCL and poly(ethylene phosphoric acid) (PEPA) as an efficient compatibilizer for PCL/HAp mixtures that are able to form ES fibers with improved mechanical characteristics. The materials obtained in the presence of vancomycin exhibited incremental drug release against Staphylococcus aureus (St. aureus).

In bone surgery and orthopedics, bioresorbable materials can be helpful in bone repair and countering post-op infections. Explicit antibacterial activity, osteoinductive and osteoconductive effects are essential to achieving this objective. Nonwoven electrospun (ES) fibers are receiving the close attention of physicians as promising materials for wound dressing and tissue engineering; potentially, in high contrast with dense materials, ES mats hamper regeneration of the bone extracellular matrix to a lesser extent. The use of the compositions of inherently biodegradable polyesters (poly(ε-caprolactone) PCL, poly(lactoglycolide), etc.), calcium phosphates and antibiotics is highly prospective, but the task of forming ES fibers from such compositions is complicated by the incompatibility of the main organic and inorganic ingredients, polyesters and calcium phosphates. In the present research we report the synthesis of hydroxyapatite (HAp) nanoparticles with uniform morphology, and demonstrate high efficiency of the block copolymer of PCL and poly(ethylene phosphoric acid) (PEPA) as an efficient compatibilizer for PCL/HAp mixtures that are able to form ES fibers with improved mechanical characteristics. The materials obtained in the presence of vancomycin exhibited incremental drug release against Staphylococcus aureus (St. aureus).

Composition of the immobilized layer plays a crucial role in metal adsorption properties of complexing organo-mineral materials. Ignoring the specific features of chemical reactions on solid surface can lead to a significant deterioration in the target properties of the resulted materials. In this research we demonstrated that rationally designed surface-assembling synthesis of organo-silica with covalently immobilized fragments of dipicolinic acid (DPA) resulted in the adsorbent that is capable quantitively recover almost all Rare Earth elements (REEs) from multielement solution with pH > 1.7. In ten consecutive adsorption/desorption cycles no noticeable loss of its efficiency was found, with a mean value of REEs recovery larger than 97%. The adsorbent has been used to recover REEs from model solutions (22 metal ions in 0.5 mol L−1 NaCl) and real leaching solution of waste of fluorescent lamps. It was demonstrated that even 3200-fold excess of Fe and Cu ions only slightly reduces REEs recovery. The adsorbent is capable to recover above 80% of all (except La) REEs from acidic leaching solution from fluorescent lamps with enrichment factors above 600. After adsorption of Eu3+ and Tb3+, the resulting materials exhibited strong red and green luminescence, respectively, indicating chelating mechanism of REEs adsorption on SiO2-DPA.

Gold nanoparticles (Au NPs) and reduced graphene oxide (rGO) mediated hyperthermia are the two most widely explored systems used for the photothermal ablation of cancer cells. We show that the photothermal conversion and efficiency of these nanomaterials can be improved not only by combining them into one material, but also by forming bimetallic AuPd embedded on rGO. The AuPd NPs–rGO nanocomposites were prepared by a simple one-step chemical reduction technique using the individual metallic salts, graphene oxide (GO) and ascorbic acid as a green reducing agent. The AuPd NPs–rGO nanocomposites were covalently functionalized with poly(ethylene glycol) (PEG) chains and characterized by high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and UV/Vis spectrophotometry. Covalent attachment of PEG units to the AuPd NPs–rGO nanocomposites greatly improved the solubility and stability of the nanocomposites in biological media and ensured its biocompatibility towards cancer cells such as HeLa cells. The near-infrared photothermal properties of AuPd NPs–rGO–PEG nanocomposites were evaluated using a continuous laser at 800 nm with power densities between 0.5 and 2 W cm−2. The nanocomposite was successfully used for the in vitro photothermal ablation of HeLa cells. At 1 W cm−2, the total killing of HeLa cells was achieved through irradiation of AuPd NPs–rGO–PEG nanocomposites incubated cells for 10 min at a particle concentration of 20 μg mL−1. Such high efficiency was principally assigned to the synergetic effects of rGO and AuPd NPs.

3D printing technology has an enormous potential to apply to chemical engineering education. In this paper, we describe several designs of 3D printed mesoreactors (Y-shape, T-shape, and Long channel shape) using the following steps: reactor sketching, CAD modeling, and reactor printing. With a focus on continuous plug flow mesoreactors (PFRs, i.d. = 2 mm), fluid mixing phenomena were explored by using a passive mixing method. The small channel of mesoreactors facilitates the stability of a laminar flow in the system at low Reynolds number. With changes in flow rates (0.2 and 4.0 mL/min) and channel geometry (0° and 90° outlet angle), fluid mixing was controlled. Our results provided that 3D printed mesoreactors can be possibly used in teaching fluid dynamics, chemical kinetics, and reaction engineering, which are main courses of the chemical engineering undergraduate program. Furthermore, the cost of mesoreactor printing was suitable (

The electrochemical properties of triamcinolone acetonide on carbon-paste electrodes have been studied. By the cyclic voltammetry method it was revealed that this steroid is irreversibly reduced at a potential from -0.9 to -1.4 V, depending on the solution pH and the potential sweep rate, while an increase in the sweep rate results in a shift of the peak position to more negative potentials. The limiting stage of the process of reducing triamcinolone acetonide on carbon-paste electrodes is diffusion. The calibration graph was linear in the concentration range from 2 to 46 μmol/L, the detection limit was 1.5 μmol/L. The possibility of using differential pulse voltammetry on carbon-paste electrodes for the determination of the active substance content in ampoules of a suspension of Kenalog 40 was shown.

A set of samples of novel colorized zinc oxide-nanosilica composites was synthesized and analyzed. The color and optical properties are directly dependent on ZnO concentration in the composites. Visible light-driven (λ = 550 nm) catalytic activity on the degradation of pharmaceuticals was tested and indicated that the most active sample with 9 mmol of ZnO per 1 g of SiO2 was ca. 13 times (toward propanolol), 24 times (toward carbamazepine) and ca. 37 times (toward metoprolol) more effective than blank (catalyst-free photolysis) decontamination. Besides showing a typical charge transfer band on the UV–Vis spectra, all the samples demonstrated a visible light absorbance at ca. 500 nm. Due to the diminution of ZnO particles size, the sample with the minimal concentration of zinc oxide exhibited pronounced luminescence at the region of >500 nm. The microscopy confirmed the decrease of ZnO agglomerated crystalline phase with diminution of ZnO concentration over SiO2 matrix. XPS studies provided information about the chemical species contributing to the formation of nanocomposites, including the presence of some unexpected trace elements, and also the surface effects of incorporating ZnO nanoparticles into SiO2 matrix also. With the help of elemental analysis, certain impurities in ZnO were identified, which might be responsible for the outstanding optical and catalytic behavior of the samples. The toxicity results confirmed that applied process can be used for detoxification of wastewater.

A nanocomposite material with an EDTA counterpart, ethylenediamine triacetate (ED3A), covalently fixed on the surface according to the core–shell technique is obtained in order to develop adsorbents for reversible analytical concentration of heavy-metal ions from solutions. The material is characterized using the methods of IR spectroscopy, X-ray phase analysis, elemental analysis, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. It is shown that magnetite nanocrystallites with a size of 8–10 nm in Fe3O4@SiO2@ED3A are coated by a layer of silicon oxide that enhances 200- to 10-fold the stability of nanoparticles in the aqueous solutions in the range of pH 1–8. It is shown that the separation time of nanocomposites using a NbFeB magnet does not exceed 10 s. According to the data of elemental analysis, the concentration of functional groups on the nanocomposite surface is 0.32 mmol/g. Sorption isotherms of a number of metals on Fe3O4@SiO2@ED3A are studied. They indicate the chemical character of the metal adsorption processes due to their complexation with functional groups. The conditions of sorption concentration of the Fe(IIІ), Cu(II), Pb(II), Zn(II), and Cd(II) ions from aqueous solutions and their desorption are studied. The affinity of the obtained nanocomposite to heavy-metal ions decreases in the series of Fe(IIІ) > Cu(II) > Pb(II) > Cd(II) ~ Zn(II). It is shown that all the studied metals (except for Zn(II)) are quantitatively recovered on Fe3O4@SiO2@ED3A from weakly acidic aqueous solutions and are completely desorbed into the solution of 1.0 M HCl or HNO3.

Afacile and robust synthesis of carbon dots (CDs) emitting blue-light in water without activation and stabilization has been developed by pyrolysis of citric acid (CA) adsorbed in silica gel (SiO2) pores. Effect of the host pore size on luminescent properties of SiO2@CDs nanocomposite as well as water suspension of CDs has been studied. The synthesis conditions such as concentration of the precursor, duration of synthesis also have been investigated. It has been demonstrated that upon the thermal treatment of silica gels saturated withCA (60% of maximum loading) at 170 °Cfor 5–600 min, luminescent CDs are shaped inside the nanoreactor pores. These SiO2@CDs emit photoluminescence centered at 450 nm. Silica-immobilized CDs can be separated from the source molecules and sideproducts by centrifugation, which allows avoiding the dialysis of the resulted mixture and so improve the scaling of the synthesis. The CDs can be easily released from SiO2@CDs by washing it with water. Water-eluted CDs demonstrate photoluminescence at 447 nm. The smaller pore size of the host and longer time of thermal treatment promote the formation of the CDs with better photoluminescent peak symmetry and higher quantum yield up to 10.1%.

Electrochemically-derived well-crystalline mesoporous silicon carbide (pSiC) was used as a host for cobalt nanoparticles to demonstrate superior catalytic performance during the CO hydrogenation according to Fischer-Tropsch. Colloidal Co nanoparticles (9 ± 0.4 nm) were prepared independently using colloidal recipes before incorporating them into pSiC and, for comparison purposes, into commercially available silica (Davisil) as well as foam-like MCF-17 supports. The Co/pSiC catalyst demonstrated the highest (per unit mass) catalytic activity of 117 µmol.g(CO)-1.g-1(Co).s-1 at 220 °C which was larger by about one order of magnitude as compared to both silica supported cobalt catalysts. Furthermore, a significantly higher C5+ hydrocarbons selectivity was observed for Co/pSiC. The stable performance of the catalyst is attributed to the high dispersion of the active phase and the use of pSiC acting as a thermally conductive and chemically inert mesoporous support., info:eu-repo/semantics/published

In the course of the study, methods for ensuring the centeringof particlesofbulkmaterialintheairflowmovinginthepneumaticductofthe seeder were investigated. To solve this problem, it is proposed to use a conical confusor. The aim of the study was to obtain the functional dependences of the movement of particles in a conical airflow guide (confusor) for the conditions of transportation of the sown particles on the basis of force analysis and to identify the nature of the movement of the sownparticlesinataperingairflow.Duringthestudy,todescribethemotion of particles in a vertical tapering pipe, a system of expressions was substantiated. The developed mathematical model of particle motion in a conical air flow, implemented in the MathCAD mathematical package, allowscalculatingboththeparticletrajectoryandthevelocityparametersof the air flow and the particles to be sown. The digital calculation results in the MathCAD program are in good agreement with the finite element calculations. The magnitude of the error in air velocity is less than 1%. The differences in the velocities of the transported particles in the calculation options do not exceed 7%. The installation of a conical guide helps tofocus the flow of particles in the central part of the narrowed air line. In this case, part of the particles in the central part of the guide will retain the initial longitudinaltrajectory.Theangleattheapexoftheconeandtheparameters of the particles affect the speed and angle of the tangent contact of the particle with theguide.

Organosilica materials containing λ-carrageenan on their surface are synthesized. The conditions for the immobilization of the polysaccharide, such as phase contact time and pH and concentration of solutions, are optimized. It is shown that the chemisorption of the polysaccharide passes through ion exchange multipoint immobilization, which provides a high hydrolytic stability of the prepared organosilica. The rate of washing of λ-carrageenan to the solution does not exceed 0.5%. The physical and chemical characteristics of the new material are studied. In particular, it is shown that the material is completely stable up to 200°C and reversibly desorbs water at 120°C; it well adsorbs 1,4-dioxane from the gas phase and desorbs it under heating to 70°C. This ensures the use of the prepared carrageenan-containing material as an adsorbent for a solid-phase cartridge designed for the adsorption preconcentration of 1,4-dioxane in its headspace gas chromatographic determination in samples of nonionic surfactants. The developed procedure ensures the determination of 1,4-dioxane by gas chromatography with a flame ionization detector in the concentration range 0.012–3.750 mg/L with a limit of detection of 0.0014 mg/L. Preconcentration lowers the limit of detection in the determination of 1,4-dioxane by 50 times.

It was demonstrated that traces of rare earth elements (REEs) can be quantitatively preconcentrated from contaminated water with pH ≥ 3 on a silica-based adsorbent with covalently immobilized amino-di(methylenephosphonic) acid (SiO2-AdPA). However, recovery of REEs from the adsorbent required utilization of a strong mineral acid. In order to reduce environmental impact and increase the reusability of the adsorbent, a ligand-exchange approach that includes treatment of the adsorbent with strong complexing ligands was used. The eluting potential of several ligands was investigated, namely EDTA, 5-sulfosalicylic acid (SSA), citric acid (CiA), aminosulfonic acid (AmSA), α-hydroxyisobutyric acid (HBA), oxalic acid (OxA) and ascorbic acid (AsA). The results were compared to those obtained by acidic treatment (HCl or HNO3). It was demonstrated that the complete desorption of all REEs can be achieved by using 10−2 mol L-1 EDTA solution with pH = 8.0, while acidic treatment requires 1.0 mol L-1 HNO3. Reusability tests demonstrated complete stability of the adsorbent for at least five consecutive adsorption/desorption cycles with no decrease in its adsorption characteristics.

Porous SiC with uniformly sized 12 nm and 22 nm spherical mesopores was synthesized from nanocomposites of polycarbosilane (PCS) preceramic polymer and xerogels of Ludox® SiO2 nanoparticles as templates. The influence of PCS type (Mw 800 and 2000 Da), PCS : SiO2 ratio, pyrolysis temperature 1200–1400 °C, and addition of Ni complex to the preceramic composite was studied with respect to the SiC porous morphology, crystalline structure and chemical properties. We found that the pore walls of Ni-free por-SiC are composed of relatively large (20 nm) crystallites embedded inside a poorly crystalline SiC/SiC1+x phase. Increasing the pyrolysis temperature resulted in an increase of the large crystallites fraction, as well as of the stability with regard to air oxidation; however, some degradation of the porous morphology was noted too. The presence of Ni (1.5% wt relatively to PCS) noticeably improved the crystallinity of por-SiC prepared at 1200–1300 °C, with no degradation of the porous morphology occurring. On the other hand, higher Ni loadings and temperatures led to the transformation of the porous morphology into aggregates of irregularly packed large crystallites.

New silica-based adsorbent with covalently immobilized groups of triton X-100 has been proposed for extraction and concentration of 2,4-dichlorophenoxyacetic acid (2,4-D) from water bodies. The recovery of this pesticide into adsorbent phase occurs in the form of its ionic associate with cationic surfactants (CSAS). It was shown that the application of cetyltrimethylammonium bromide made it possible to achieve the pesticide extraction ratio as high as 94%. Elution with acetonitrile allows us to achieve a 50-fold absolute concentration of 2,4-D making it possible to perform its determination by the high performance liquid chromatography method with ultraviolet detection, where the detection level is 0.07 mg/dm3 and the linearity range is from 0.09 to 0.20 mg/dm3.

Advances in nanotechnology have seen the development of several microbiocidal nanoparticles displaying activity against biofilms. These applications benefit from one or more combinations of the nanoparticle properties. Nanoparticles may indeed concentrate drugs on their surface resulting in polyvalent effects and improved efficacy to fight against bacteria. Nanodiamonds (NDs) are among the most promising new materials for biomedical applications. We elucidate in this paper the effect of menthol modified nanodiamond (ND-menthol) particles on bacterial viability against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. We show that while ND-menthol particles are non-toxic to both pathogens, they show significant antibiofilm activity. The presence of ND-menthol particles reduces biofilm formation more efficiently than free menthol, unmodified oxidized NDs and ampicillin, a commonly used antibiotic. Our findings might be thus a step forward towards the development of alternative non antibiotic based strategies targeting bacterial infections.

Diamond nanoparticles (NDs) have demonstrated great promise as useful materials in a variety of biomedical settings. In this paper, the antimicrobial and antibiofi lm activities of variously functionalized NDs against two common bacterial targets Gram-negative bacterium Escherichia coli and Gram-positive bacterium Staphylococcus aureus are compared. Hydroxylated (ND-OH), aminated (ND-NH 2 ), carboxylated (ND-COOH), mannose (ND-Mannose), tri-thiomannoside (ND-Man 3 ), or tri-thiolactoside (ND-Lac 3) - modifi ed NDs are fabricated and evaluated in the present work. Of these, the mannose-modified NDs are found to interfere most strongly with the survival of S. aureus, but not to influence the growth of E. coli . In contrast, particles featuring lactosyl units have the opposite effect on S. aureus growth. Sugar-functionalized NPs reported to display antibacterial effects are rare. Only ND-COOH particles are seen to have any effect on the growth profile of E. coli, but the effects are moderate. On the other hand, both ND-NH 2 and ND-COOH are found to inhibit E. coli -induced biofilm formation at levels comparable to the known E. coli biofilm disruptor, ampicillin (albeit at concentrations of 100 μg mL -1). However, none of the modified particles examined here reveal any significant activity as disruptors of S. aureus -induced biofilm formation even at the highest concentrations studied.

A technique for phthalate extraction from water samples has been proposed. This technique is based on the preconcentration of target substances using the dispersive liquid-phase microextraction with subsequent determination of these substances using a gas chromatograph with flame ionization detector. Under the optimal conditions of microextraction (involving 0.25 cm3 of acetonitrile and 0.05 cm3 of chloroform in 10% NaCl solution for water sample volume of 8 cm3) concentration factors of phthalates amount to 360–393 at their extraction degree of 91–98%, while the detection limit can reach 3–8 μg/dm3. The proposed technique is characterized by a high accuracy and reproducibility.

Tungsten oxides, including WO3 and mixed valent oxides, are formed in unpolished porous Vycor glass (PVG) by ultraviolet photolytic decomposition of adsorbed tungsten hexacarbonyl. The relative amounts of the oxides formed are determined by a competition between aggregation and oxidation, and both are influenced by CO pressure gradients created by the photoinduced release of CO within the nanoporous silica matrix. These gradients sweep the hexacarbonyl precursor into the outer regions of the PVG, increasing amounts of tungsten nearer the surface, thereby enhancing the rate of aggregation relative to the rate of oxidation and promoting the formation of the mixed valent oxides. Thermolysis of the physisorbed hexacarbonyl, on the other hand, produces predominantly WO3. Thermolysis promotes desorption of the physisorbed W(CO)6, reducing the amount of tungsten available, permitting oxidation to be the predominant process over aggregation, leading to WO3 formation.

The quantification of peroxynitrite (ONOO−, PON) and hydrogen peroxide (H2O2) is intrinsically difficult as both species show similar oxidative features located within a narrow potential. The sub-second lifetime of ONOO− at neutral pH further complicates the analysis. In this paper, we examine the electrocatalytic activity of cobalt phthalocyanine tetracarboxylic acid (CoPc–COOH) loaded reduced graphene oxide (rGO) films towards peroxynitrite and hydrogen peroxide detection. The rGO/CoPc–COOH matrix is synthesized by the reaction of graphene oxide (GO) and CoPc–COOH at 90 °C for 5 h under ultrasonication. The integration of CoPc–COOH and the reduction of GO to rGO was confirmed by X-ray photoelectron spectroscopy, FTIR, Raman, UV-vis spectroscopy and electrochemistry. The rGO/CoPc–COOH film showed high electrocatalytic activity and specificity for ONOO− at anodic potential with a sensitivity of ≈11.5 ± 1 nA nM−1 and a peroxynitrite detection limit of ≈1.7 nM. The rGO/CoPc–COOH films further exhibited electrocatalytic reduction of H2O2 with a sensitivity of 14.5 μA mM−1 and a detection limit of ≈60 μM for H2O2.

A facile and robust synthesis of carbon dots (CDs) emitting blue-light in water without activation and stabilization has been developed by pyrolysis of citric acid (CA) adsorbed in silica gel (SiO2) pores. Effect of the host pore size on luminescent properties of SiO2@CDs nanocomposite as well as water suspension of CDs has been studied. The synthesis conditions such as concentration of the precursor, duration of synthesis also have been investigated. It has been demonstrated that upon the thermal treatment of silica gels saturated with CA (60% of maximum loading) at 170 °C for 5–600 min, luminescent CDs are shaped inside the nanoreactor pores. These SiO2@CDs emit photoluminescence centered at 450 nm. Silica-immobilized CDs can be separated from the source molecules and side-products by centrifugation, which allows avoiding the dialysis of the resulted mixture and so improve the scaling of the synthesis. The CDs can be easily released from SiO2@CDs by washing it with water. Water-eluted CDs demonstrate photoluminescence at 447 nm. The smaller pore size of the host and longer time of thermal treatment promote the formation of the CDs with better photoluminescent peak symmetry and higher quantum yield up to 10.1%.

Silica gel with covalently immobilized N-Benzoyl-N-phenylhydroxylamine fragments (SiO2-BPHA) has been successfully prepared using surface assembling approach. The SiO2-BPHA is characterized by FTIR, high-resolution X-ray photoelectron spectroscopy, by SEM and BET measurements, and by elemental and thermogravimetric analysis. It has been demonstrated that SiO2-BPHA can be successfully used as an adsorbent for dispersive solid-phase extraction (DSPE) and separation of Rare Earth Elements (REE) from aqueous solution. The adsorbent capacities toward La3+, Ce3+, Pr3+, Nd3+, Sm3+, Eu3+, Gd3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3+, Yb3+, Lu3+, and Y3+ ions have been determined from the adsorption isotherms. Adsorption kinetics and competitive adsorption of REEs from multielement solution have been studied as a function of pH. Sharp changes of REEs recovery on SiO2-BPHA have been observed in the pH range 3.3–5.0 with more than 95% of the metal adsorption at pH ≥ 5.0. The complete desorption of all REEs from SiO2-BPHA can an in 0.1 mol L−1 of HNO3. Reusability test has demonstrated that SiO2-BPHA can be used for quantitative adsorption of almost all (average adsorption of Ce and Pr ions is about 90%) REEs from multielement solution with pH = 5.0, without loss in adsorption capacity and selectivity for at least ten consecutive cycles. It has been found that essential (more than 100 times) growth of distribution coefficient in respect to the atomic number of REE is observed for multielement solution analyzed. In optimal conditions, the selectivity factor is about 80 for Lu/La and Yb/La pairs and takes about 60 for Tm/La pair, which serves as an evidence of the high potential of SiO2-BPHA in REEs separation.

The aim of the research was to establish the influence of the number and height of blades of a drum mixer on the quality of the prepared mixture of concentrated feed. The research method of the drum mixer provided for the experimental determination of the coefficient of variation (unevenness) of the mixture with a three-level combination of the blades height and their number. The absence of an extremum according to the obtained data required the use of a fourth level of the number of blades. Computer processing of the results made it possible to establish a functional dependence of the influence of design factors on the quality of the mixture. The implementation of the used research methodology for the operation of the drum mixer made it possible to establish an adequate functional dependence of the influence of the number of blades and their height on the quality of the mixture. The number of blades used practically does not affect the coefficient of variation of the content of the control component. The values change less than experimental error. However, existing trends indicate a slight (about 1%) decrease in the coefficient of variation of the mixture with an increase in the number of blades from 2 to 8 pcs. For 50 kg of feed in a drum capacity of 0.26 m3, the height of the blades is about 0.15 m. The increase or decrease in the height to 0.125 m or 0.175 m affects the quality of the mixture, increasing the coefficient of variation from 20.6% to 34-50% at the proportion of the control component of 1% and the mixing time of 200 seconds.

The conditions of liquid microextraction of diphenylketones for two variants of such microextraction (capillary and dispersive) have been optimized and compared. A technique was developed for the preliminary separation and concentration of diphenylketones by the dispersive microextraction from different waters with their subsequent gas-chromatographic determination.

Optical sensor element for the determination of tetracycline (Tc) based on europium-sensitized luminescence of the SiO2–polyelectrolyte (PE)–Eu(III) hybrid film was worked out. The morphology of the hybrid films and their adsorption capacity towards Tc were function of PE and non-ionic surfactants content in silica coating solution. The presence of a mixture of Tween 20 and triblock copolymer Pluronic F-127 in a molar ratio Tween 20:Pluronic F-127 = 35:2.5 in silica sol resulted in the formation of films with uniform and ordered mesoporous structure. The use of polyvinyl- and polystyrene sulfonic acids during sol–gel synthesis greatly increased Tc adsorption within the hybrid films. SiO2–PE–Eu(III) films were used for Tc determination in milk with a linear response range in 0.6–10 μmol L−1and LOD 0.3 μmol L−1 of Tc. The sensitivity and selectivity of determination increased in the presence of citrate ions in solution.