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Heat exchangers are important components of cryogenic installations. The modern and advanced cryogenic systems have bulky heat exchangers, weigh tens of tons, are made of copper and its alloys, stainless steel or aluminum. The main challenge in the field is related to the need to reduce size and weight of the heat exchangers by using appropriate construction shape and modern materials. Heat exchangers used in cryogenics can be divided into three main groups: tubular, spiral and efficient or compact exchangers. In ...

The bactericidal properties of silver and its compounds are known for a long time. Silver has antimicrobial properties against a wide range of microorganisms, not only bacteria, but also some fungi, as well as viruses. However, several mechanisms have been identified for the formation of resistance to silver in bacteria. It?s relevant to search for new reagents, which would increase the aggressive stability of the argentum?s compounds. Purpose is study of the influence of various chemical nature SAS on the aggrega...

It is shown that the corrosion-electrochemical behavior of coatings with iron (cobalt) tungsten alloys depends on the content of the refractory component, and the increase in chemical resistance in an acidic medium is due to the formation of acidic tungsten oxides on the surface. The use of artificial neural networks allowed us to identify the most significant parameters that determine the corrosion resistance of alloys. Electrolysis was carried out in a glass cell for a two-electrode scheme using planar positione...

In this study, the antibacterial properties of pharmaceutical grade kaolin modified with copper were tested to determine its suitability to be used in pharmaceutical and cosmetic applications. Both kaolin?s and copper?s antimicrobial activity have been highlighted by multiple researches. The sample was prepared by submerging the kaolin into saturated CuCl2 solution in order to load the nanoparticles with copper, utilizing the cation exchange capacity (CEC). Mineralogical analysis was conducted by X-ray diffraction...

The purpose of the paper is to obtain a new composite material based on chemically functionalized nanoparticles dispersed in plastomer matrix. The dispersion of the ZnO nanoparticles in a plastomer matrix (PETr) leads to a high-performance polymeric material with multi-functional, antibacterial, and plastomer-specific processing properties. In this paper, elastomeric nanocompound materials were selected, due to performance properties such as: antimicrobial, resistance to aggressive chemical agents, mechanical prop...

Nowadays, emulsions have been increasingly studied due to their application in different fields such us cosmetic, agriculture, pharmaceutical, paint and oil industries. Essential oils were widely used in the cosmetic industry as antimicrobial and antioxidant agents. This study investigated essential oil entrapment in beeswax in order to prolong its biological activities as oil in water (O/W) emulsion. Moreover, one of this work aim was to achieve stable beeswax-essential oil (extracted from Rosmarinus Officinalis,...

The ultimate goal of this study is to obtain antimicrobial textiles, useful in various skin infections with different bacterial strains, due to the unique properties of contained essential oils, such as: antimicrobial and antiinflamatory effects. Four different matrices of biologic active systems in forms of stable emulsions were used in this study, namely: bee wax ? essential oil, chitosan ? agar ? essential oil, xanthan gum ? essential oil, xanthan gum ? gelatin ? essential oil and four different types of essent...

Noble metallic nanoparticles, silver (Ag) and gold (Au) especially, are very important in modern nanotechnology due to their various applications in medicine, pharmacy and diagnosis especially due to their proven antimicrobial and antioxidant activity. Both silver (AgNPs) and gold (AuNPs) nanoparticles can be synthesized using conventional or unconventional methods and, in recent years, the unconventional methods that rely on the biosynthesis of metallic nanoparticles from different plants and plant parts are cons...

This article describes the design of a compact Wilkinson coupler with an operating frequency of 1000 MHz. This device belongs to the class of power dividers, which are widely used in various microwave systems. The classical design consists of two segments of the transmission line with a length of a quarter of the wavelength, which are connected through the resistance R with a nominal value of 100 Ohms. The presence of resonant segments leads to the fact that the device has large dimensions at low frequencies of th...

In this paper, an original design of a directional coupler with five connected quarter-wave plumes is proposed. This number of loops allowed to increase the bandwidth of operating frequencies, but at the same time the length of such a device becomes large. This leads to the fact that it is necessary to use more dielectric material on which the micro-plane couplers are made. In order to reduce the cost of manufacturing the device can be used miniaturization of microplane devices. In this article the design of the c...

Directional couplers implemented on two pairwise identical segments of the transmission line, have only one working bandwidth. In order to organize the performance of the structure on two ranges or more, it is necessary to make design changes to the standard device. For example, for operation at two frequencies, idle plumes are added to the design of the coupler. However, this has further increased the dimensions of the coupler, especially at low frequencies, and in some cases the design may be practically unsuita...

We studied the effect of Cu and Ni nanoparticles on the plant Triticum vulgare. Observing the germination energy, we faced a decrease 16.7 times for Ni? and total suppression for Cu. These nanoparticles reduced the growth of seedlings and affected the placement of lateral roots, which grew like a ?goose-paw?. The total sum of reactive oxygen species ended up with an increase in the roots after exposure to Cu? (up to 35.8% compared to the negative control). Expressed statistically significant (in comparison with th...

Currently the problem of surface water quality is relevant and requires urgent solution. There is an intensive growth of rivers? water using those results in deterioration of water quality and hydrological regime. In the conditions of the Mykolaiv region (Ukraine) local water resources are limited. The present situation is aggravated by anthropogenic pollution of surface and groundwater by utilities and agrarian sector. Monitoring surveys of surface water quality are an important tool for environmental assessment ...

The energy consumes for district or industrial heating and electrical energy are in most of cases concomitant. The paper analyses from the point of view of the First and Second Laws of Thermodynamics the advantages of producing heat and mechanical power each one individually or through cogeneration. It is clearly pointed out that the energy balance induces the idea that the most efficient conversion process is to produce heat in an individual boiler while the mechanical power production in a steam turbine system i...

The global burden of diabetes has elevated significantly during last decades. It has highly been appreciated that appropriate animal models that familiarly resemble the hyperglycemia and type 2 diabetes are urgently needed for understanding and seeking of concepts cover biochemical and molecular mechanism implicated early in the development and progression of the disease. To this purpose we studied the response of Cyprinus carpio red blood cells (RBC) to high glucose exposure in vitro and potentials of medicinal h...

The main purpose of this scientific work is to review the current methods of multifunctional material design, and to establish approaches based on multiscale non-deterministic analyzes that can be used to model composite coatings. Analyzing of the literature data showed that methods of computer modeling of materials can be classified by the following. The first group represents approaches in which for selected values of functional properties the process of selecting materials is based on a combinatorial search in ...

Using the open-source library for calculations in the field of kinetics and thermodynamics Cantera, a software module has been developed. Computer simulation of dry reforming of methane in a membrane reactor-contactor has been performed. The one-dimensional mathematical model of gas flow in a porous catalytic coating is used. The influence of a number of parameters, such as characteristics of pores of catalytic membrane coating, and the temperature and the flow rate of the gas mixture on the dry reforming of metha...

Atmospheric air is the primary component used in air separation plants. Wet air is a mixture of dry air particles and vaporous water particles, a mixture in which the components do not chemically interact and are thought to be approximately perfect gases. Atmospheric air to be processed in a separation unit needs to be cleaned of all impurities that can cause damages in the main components of the plant. The hazardous impurities that can be found in the atmospheric air used to generate oxygen, nitrogen and rare gas...

The creation of in vitro model of human BBB, completely identical to the real BBB, was necessary for the possibility of studying the transport and penetration of drugs and xenobiotics and is still very popular and urgent task. In order to reproduce the most close to the real in vitro model of BBB, a microfluidic platform is used, which allows more carefully reproduce the structure of BBB, as well as physiological tangential stress on the surface of endothelial cells (0.3 - 2 PA). An innovative development was a ne...

Silicon carbide is a promising material for heat-loaded units due to its high strength at elevated (up to 1500 °C) temperatures and good thermal conductivity. However, when heated in oxidising media SiC tends to lose its properties, and development of SiC-based materials able to withstand such conditions is a challenging issue. The present research discusses development of a heat- and oxidation-resistant structural ceramics based on SiC with oxide sintering aids. Sintering aids were chosen in ternary systems CaO-A...

The possibility of applying biological macromolecules, especially DNA, in nanobioelectronics currently attracts attention of researchers. For example, DNA can be used when designing electronic microarrays and as a molecular wire. Therefore, the study of the conducting properties of polynucleotide chains is of great interest. In a number of publications about biophysical experiments on the charge transfer along DNA it is assumed that a charge is transferred via a super-exchange mechanism at short distances of 2?3 n...

An electrolyte for chromium based nano-composite electrolytic coatings (nano-CE?) obtaining has been developed. Nano-CEC was applied on steel of the St 3 brand with constant exposure to ultrasound, electrolyte temperature 50?60°?, current density 7kA/m2 for 1 and 2 hours from two variants of chromium-plating electrolytes, differing in the fact that one electrolyte contained strontium sulfate, in the other ? without it. Quantitative assessment of the corrosion resistance of nano - CEC deposited on steel St.3, was e...

Hyaluronic acid (HA) is rightfully considered as a promising and advanced polymer for development and producing a variety of applications in medicine, biotechnology and tissue engineering. One such trend is electrospun fiber materials obtained from HA solutions. However, HA has absolutely highly resistance to volatile organic solvents (such solvents are strongly encouraged for utilizing in case of electrospinning), that make the obtaining of polymer fibers difficult. Despite this, some authors could elaborate nano...

Presently, energy efficiency (EE) improvement is considered a part of the state environmental policy in Russian Federation, an instrument for modernization of national industry and a tool to enhance its environmental performance. This approach holds much promise regarding ceramics manufacturers, where industrial sites are most energy-intensive and are classified as category I objects in terms of negative environmental impact. Since 2010s Russian practitioners have tended to evaluate energy efficiency and environme...

This study aims to investigate the functionalization by pad-dry-cure method of 100% cotton fabrics with colloidal dispersions based on TiO2:N and SiO2 nanoparticles (NPs) in different molar ratios (1:0.5, 1:1, 1:1.5 and 1:2). For the preparation of colloidal dispersions the chitosan was used as stabilizing agent. Self-cleaning performance of the functionalized samples was qualitatively assessed based on Methylene Blue and Brilliant Green stain removal ability under UV radiation. Stain photodegradation efficiency w...

In this paper we present the results obtained regarding the functionalization of the surface of sheepskins using nanocomposites based on reduced graphene oxide - TiO2-Ag and reduced graphene oxide - TiO2-Cu in order to obtain leather with antimicrobial and photocatalytic properties. The nanocomposites were integrated in film forming polymer composites and were applied by spraying on sheepskin surfaces. Sheepskin surfaces were characterized using scanning electron microscopy (SEM), physico-mechanical methods, photo...

The aim of this work was to obtain new medical biomaterials based on a biocompatible polymer polytetrafluoroethylene (PTFE), modified with the drug, ketoprofen (KP), and gold nanoparticles (Au NPs). The biological inertness of PTFE, hydrophobicity, elasticity, low weight prevents sticking to wounds and makes fibrous materials based on it ideal for dressing and obturators. Ketoprofen gives anti-inflammatory properties to the material, while Au NPs provides it with antibacterial ones. Biomaterials based on porous PT...

New materials based on Au and Ag nanoparticles stabilized in a matrix of microcrystalline and bacterial cellulose were prepared for medical applications. Au and Ag nanoparticles were synthesized in i-PrOH by metal vapor synthesis (MVS) and incorporated into the polysaccharide matrix using metal-containing organosol. The MVS is an efficient route of purposeful synthesis of metallic nanoparticles and their derived composites. Microcrystalline cellulose brand Avicel PH-101 with a polymerization degree of 180 and an a...

Wood protection is carried out in accordance with the requirements for the specific applications. It is commonly admitted to perform class 2 and 3 coatings for surface finish according to EN 335. The effect and interaction between wood mass and amorphous titanium dioxide are investigated in order to improve the quality of surface finish. Coatings with planar particles of titanium dioxide were used for dispersions applied on wooden surface in a transparent layer. The interaction between the wood surface and TiO2 wa...

Molecular simulation methods were used to describe the spiral-structure of halloysite (7 A) loaded with irinotecan in Materials Studio modeling environment. Halloysite is a clay mineral commonly used as a drug delivery system for a variety of molecules due to its suitable characteristics and its morphology. Irinotecan is a semi-synthetic drug used in the treatment of colorectal cancer and exists in an active lactone form and an inactive hydroxyl-acid anion form[1]. In this work, the anionic form of the irinotecan ...

In this research we have obtained mathematical relations between elastic constants, such as Young's modulus and Poisson's ratio, using single-crystalline silicon as an example. When the obtained relations are fulfilled, the influence of misalignment of the crystallographic directions and the coordinate axes associated with the sensing element of microelectromechanical sensors on the stress-strain state and natural frequencies of sensing element will be minimal. Therefore, the influence of such misalignment on the ...

The qualitative and quantitative composition of biomass of microorganisms has been studied in key points of artificial biocenosis: water filter, duckweed and pond snail. Metagenomic studies have shown the presence of Bacteroides and Proteobacteria types in all examined systems, however, specific representatives - Actinobacteria, Cyanobacteria, and Bacilliwere also found, respectively. A microflora peculiarity of water filter was the presence of actinobacteria. In the intestine of the pond snail (Lymnaea stagnalis ...

Micro and nanoparticles of titanium dioxide are nowadays produced worldwide for a range of applications. In our project we focus on potential use of titanium dioxide particles as UV absorber (anti-UV protective coating) for wooden construction structures. We investigate the influence of different synthesis methods on particles? morphology. Hence, material characterization has an important place in our research. Electron microscopy is a powerful tool to obtain information about the morphology of particles and their...

Inhalation delivery is a promising route of drug administration, including systemic action. It should be considered that the particles of drug aerosol should have a diameter in the range of 1 to 3 ?m. Microspherical particles based on protein molecules can provide increased bioavailability of drugs with poor water solubility. In the present work, microspherical particles of sodium caseinate with a model hydrophobic drug ? phenacetin were obtained using spray drying method. Average aerodynamic diameter of resulting...

This article describes the design of a crossover whose dimensions are miniaturized using compact elements. Crossover is a directional coupler that allows you to transmit the incoming power to the input diagonally to one output, the rest can be considered untied. Compact units are designed in such a way as to achieve identical characteristics with replaceable lines. The number of connected loops in the crossover design will affect the dimensions and bandwidth of the device. With the help of mathematical modeling, t...

The paper deals with a design and a method of milling of the invention called ?Milling device for mechanical treatment process of fine particles?. The milling device for mechanical treatment process of fine particles according to the present invention consists of a lower flange with a milling chamber having an external part and an internal part being fixedly attached to said lower flange wherein an elastic doctor blade with brushes is arranged within said internal part. The elastic doctor blade with brushes is fas...

Directional couplers can divide the input power between its outputs in different proportions. This is due to the ratio of wave resistances between two pairs of quarter-wave segments. Due to the fact that at frequencies of 2 GHz and lower couplers are also actively used, it is necessary to take care that their dimensions satisfy the radio system where they will be installed. Due to the fact that it is not always possible was investigated miniaturization as an opportunity to reduce the area occupied by the branch wh...

This study focuses on natural fiber nano-coatings - hemp and cotton modification and coating surface structure. For surface modification sol - gel technology is used. To predict the quality of the sols and the surface structure, the coatings were initially applied to different materials and tested with optical microscopy and atomic force microscopy. Samples were analyzed before and after washing as well as before modification with Fourier - transform infrared spectroscopy and energy-dispersive X-ray spectroscopy. ...

One of the most important characteristics investigated during the obtaining of polymer nanofibers is the mean fiber diameter, which depends on the technological parameters of the electrospinning process. Polyvinyl chloride (PVC) nanofibres were obtained on the NANON-01A, Japan. The following technological parameters were used to obtain nanofibers: voltage is in the range 15 to 30 kV, a solution feed rate is in the range of 0.3 to 1.0 mL/h, a distance between the collector and the tip of the syringe is in range 7.5...

It is known that one of the methods for purifying gas fraction from hydrogen sulfide is amine treatment. Various types of amines are used to remove hydrogen sulphide, carbon dioxide and carbon dioxide from petroleum gases. The choice of specific amine depends on the needs of the process. Mono-ethanolamine (MEA) (C2H4OH) NH2 and diethanolamine (DEA) (C2H4OH) 2NH are commonly used. Both are ammonia derivatives. To develop recommendations on the choice of material from which to make equipment for amine plants, compar...

New ways in the field of extinguishing by solid extinguishing is aerosol fire fighting originally developed in the 1970s by the Russian space research agency called ?SOJUZ?. More significant development in the aerosol fire extinguishers usage occured in Europe in the 1990s. Carbon as basic element of organic compounds with two allotropic modifications can be found in various modifications like diamond and graphite. Fullerenes as the third modification was discovered in 1985. Detailed analytical researches have fou...

The process of mixed oxide coatings forming on a high-silicon aluminum alloy in the cobalt-containing pyrophosphate electrolyte by the plasma-electrolytic oxidizing (PEO) method is studied. It was shown that AL25 chemical composition heterogeneity causes the consumption of part of the anode current to homogenize the treated surface, which is reflected in minimizing the content of doping components at the initial processing stage. It was established the growth of mixed oxides Al2O3·CoxOy relative mass to be a funct...

Inorganic arsenic is in very small concentrations a common constituent of surface and groundwater. However, its increased concentration may pose a significant risk to human health in connection with its carcinogenicity (a proven human carcinogen). Therefore, it is necessary to address the reduction of its concentration in drinking water using the most efficient and financially undemanding techniques. The paper analyzes current and new trends in the field of removal of arsenic from drinking water. It focuses mainly...

Treating depression is a complex process, which includes medical treatment and also psychotherapeutic approach. These two approaches are working together. There is a large scale of known treatments for depressive disorders, which had been developed since the 1950s and the therapeutic effectiveness and patient tolerance were assessed through generations. Among the studied variants, anorganic products had been Among the studied variants, anorganic products had been Among the studied variants, anorganic products had ...

Adjustment of compositions and processing techniques, mainly ? firing conditions, has been a key route for ceramics performance improvement. The present research addresses sintering process of alumina ceramics with an additive in system that was studied by non-isothermal method. Experimental samples shaped as cylinders 25 ? 6 mm in size were obtained and sintered by consequtive firings in air at heating rates q1 = 1,0 and q2 = 3,0 °?/min without curing and quenched in air. Linear shrinkage (? = ??/?, hereon ? ?) a...

Novel micro and nanostructured bioemulsions were created by innovative technologies based on fibrillar cellulose/titanium dioxide/(surfactants mixture: dodecandioyl-diglycine and sucrose diester/ethanol/water, for improved surface properties development with applications in leather industry. The high potential of using cellulose as a material for various applications: in membrane technologies for pollutant absorption, in pharmacy, etc. opens the way to obtaining new added value materials (hybrid micro and nanocomp...

Ni-P-Sn layers were deposited on the steel strip, with less carbon, by electroless method. An electrolyte based on nickel chloride, sodium hypophosphite, tin chloride and additions for bath optimizing were utilized. The influence on the deposited layers characteristics of different amounts of tin chloride in the nickel bath, respectively, 0.1g/L and 0.4g/L was studied. The conditions for electrolyte formation and optimum working parameters: pH and temperature were set. Ni-P-Sn layers were characterized by comparis...

Currently, the issue of the possible negative influence of nanoparticles on human health is inadequate in comparison with the presentation of their positives. Although there is no questioned their undeniable importance on the other hand experts agree that the precautionary principle and related measures are missing and necessary. The paper presents the pilot results of a grant project focused at the creating a methodological guideline aimed at increasing the level of occupational health and safety management at wo...

Silver and gold nanoparticles have unique antimicrobial and antifungal properties that make them excellent candidates for applications in nanomedicine, tissue engineering and bio-imaging. Green synthesis of metallic nanoparticles is preferred over conventional chemical routes because is eco-friendly, requires no reducing agents and no toxic chemicals result. In the present research study, one-pot green synthesis of noble metallic nanoparticles, namely silver (AgNPs) and gold (AuNPs) nanoparticles, from aqueous ext...

The influence of ?-ferrite amount ferrite in AISI 321 steel on its general corrosion, critical pitting temperature and potential in simulated circulating waters. The samples were made in the form of rectangular 3x3x1 mm parallelepipeds by cold mechanical method. Surface of the samples was subjected to electro-polishing. The amount of ferrite phase was determined by empirical formula. It was established, that after electromagnetic saturation of the samples, ?-ferrite content in five heats of AISI 321 steel was calc...