Останні повідомлення

Применение принципа максимума для оптимизации цепей

Решение проблемы сокращения затрат машинного времени при оптимизации электронных цепей позволяет улучшить качество проектирования. Обобщенная методология оптимизации цепей, развитая ранее на основе теории оптимального управления, позволила определить множество различных стратегий оптимизации. Определение функции Ляпунова процесса оптимизации и ее анализ для различных стратегий позволили сравнить эти стратегии с точки зрения вычислительных затрат и выбирать наилучшие из них. В то же время, наиболее обоснованным подходом для поиска оптимальной стратегии проектирования, в данной формулировке, является принцип максимума Понтрягина. Однако, использование этого принципа для решения нелинейных задач сопряжено со значительными трудностями. В настоящей работе получено решение задачи оптимизации электронной цепи за минимально возможное время процессора на основе принципа максимума Понтрягина в общем случае Nпеременных. Показано, что изученный ранее эффект ускорения процесса оптимизации совпадает с решением, полученным на основе принципа максимума. Этот факт является теоретическим обоснованием эффекта ускорения. С другой стороны принцип максимума может стать основой для разработки алгоритма оптимизации электронных цепей с минимальными затратами процессорного времени.

The Biosynthesis of Antibiotics as a Taxonomic Marker of Some Species of the Genus Pseudomonas

Наукові вісті - Птн, 06/23/2017 - 00:00

 

Background. The ability to biosynthesis of antibiotics was established for 20 of 250 species of Pseudomonas. The value of the biosynthesis of antibiotics as a taxonomic characteristic for the genus Pseudomonas is not studied. This issue will be analyzed using the experimental results.

Оbjective. The aim of the paper is to identify the ability of usage of antibiotics synthesized by certain types of bacteria of the genus Pseudomonas, as a taxonomic marker.

Methods. Methods of thin-layer chromatography (TLC) and LC/MS-analysis were used to determine the synthesis of antibiotics.

Results. A unique set of antibiotics was determined for some types of bacteria Pseudomonas, which are specific for them only: pyocyanin – P. aeruginosa, 2,4-diacetylphloroglucinol – P. brassicacearum, 2-hydroxyphenazine-1-carbo­xylic acid – P. chlororaphis subsp. aureofaciens, pyrrolnitrin and 2,4-diacetylphloroglucinol – P. protegens, batumin – P. batumici.

Conclusions. The ability to synthesize certain antibiotic substances may serve as a taxonomic marker and be used to identify certain species of Pseudomonas. However, the biosynthesis of antibiotics did not show specificity for several species. This problem requires a deeper study of different types of Pseudomonas

Biotechnological Approaches for Intensification of Ammonium Removal During Drinking Water Treatment

Наукові вісті - Птн, 06/23/2017 - 00:00

Background. Nitrogen-containing substances are the most common components of groundwater of Ukraine. It was detected, that ammonium may impact on the process of water disinfection, the appearance of nitrite in the distribution system and the problem with the taste and smell of water. The presence of high concentrations of nitrites and nitrates in water can cause methemoglobinemia in children that causes cyanosis and asphyxia. So, there is an urgent demand of developing approaches to intensification of ammonia removing from drinking water.

Objective. The aim of these studies is to examine the characteristics of biotechnological processes of nitrogen compounds removing from drinking water in its purification with charge BIOFILTER.

Methods. The object of the study was underground water from wells located in the Khmelnitsky region. The initial concentration of ammonia in water was 2.16 mg/dm3, nitrite – 0.48 mg/dm3, nitrate – 4.5 mg/dm3. Investigation of removing of nitrogen-containing substances was conducted on a pilot plant, consisting of aerator, closed contact tank and model filters with charge BIOFILTER. Water was saturated with oxygen in water aerator then came to closed contact tank, where the following parameters were gauged: the concentration of dissolved oxygen, ammonia, nitrites and nitrates. The concentration of dissolved oxygen, ammonia, nitrites and nitrates were controlled in the output water. The pilot plant was set up and worked on the well.

Results. It is shown that when the concentration of oxygen decreased from 8.0 to 6.4 mg/dm3, a sharp decrease in nitrate concentrations from 4.5 to 3.9 mg/dm3 was observed. A gradual decrease of nitrates concentrations was observed with increasing doses of consumed oxygen. It was suggested that the nitrification process was passing simultaneously with a process of denitrification as evidenced by a sharp decrease in the concentration of nitrates with a decrease in the oxygen dissolved in water.

Conclusions. A decrease in dissolved oxygen concentration violates theoretical ratio of nitrate content in water was experimentally confirmed. The actual content of nitrates in the treated water was less than the theoretical, indicating the passage of denitrification process simultaneously with a process of nitrification. The less concentration of dissolved oxygen in the water at the outlet of the filter, the deeper denitrification is held.

Isolation of Polyclonal Antibodies to Collagen by Ion Exchange Chromatography on Column with DEAE-Sepharose

Наукові вісті - Птн, 06/23/2017 - 00:00

Background. Development of new methods for isolation and purification of polyclonal antibodies.

Objective. Analysis of the efficiency of the ion exchange column with DEAE-Sepharose at isolation of polyclonal antibodies to collagen.

Methods. IgG were isolated from precipitated γ-globulin fraction of serum of immunized rabbit by ion exchange chromatography on column with DEAE-Sepharose.

Results. It was determined that the IgG output at volume ratio of 4:3 of starting material and the carrier applied to the column is 1.67 times higher than the ratio of 2:3. It is shown that IgG goes out of the column together with the protein that has a molecular weight of about 57–60 kDa. We found that 5.123 mg of IgG with minor impurities of serum proteins is obtained from 30 cm3 of rabbit’s serum.

Conclusions. The method of ion exchange chromatography on column with DEAE-Sepharose provides a high yield of IgG with few impurities and can be used as a way of pre-treatment of polyclonal antibodies.

Effect of a Complex Preparation With Polyguanidine and Microelements on Preservation, Growth and Development of Potatoes

Наукові вісті - Птн, 06/23/2017 - 00:00

Background. Preservation and increase in potato growth.

Objective. The aim of the paper is to obtain a composition for potatoes processing increasing preservation effectiveness and potato growth.

Methods. Study of influence of the complex preparation containing polyhexamethyleneguanidine and microelements on preservation, growth and development of potatoes.

Results. Treatment of potatoes using complex preparation containing polyhexamethyleneguanidine and microelements decreased tubers damage 4.3 times during preservation. Spraying tubers with PGMG and microelements solution before planting caused growth stimulation of potato plants in the early stages of growth and increased potato productivity for 12–23 % depending on the concentration of microelements. The greatest effect was observed in cases where potatoes were treated with PGMG (0.1 %) and microelements in total concentration of 0.4 %. Potato productivity was increased by rising tubers number.

Conclusion. Optimal concentration to achieve a positive effect was determined.

Pecularities of Composite Lacto- and Bifidoprobiotic Biotechnology: Determination of Rational Dose Influence upon Chicken Broilers’ Performance

Наукові вісті - Птн, 06/23/2017 - 00:00

Background. The EU decision completely stopped the use of promoter antibiotics as fodder therapeutic and prophylactic additives for animals from 01.01.2006. Therefore, probiotic preparations containing adjuvant microorganisms for the intestine of the individual are actively developed and introduced into the practice of livestock. The use of environmentally compatible probiotic preparations has become a priority in poultry farming.

Objective. The aim of the paper is to identify the features and effectiveness of the rational dose and the temporal regime of using the feed lactobiphidoprobiotic in production conditions on the control and experimental groups in 1000 heads of broiler chickens at poultry farming enterprises.

Methods. The main zootechnical indices were studied in accordance with the generally accepted methods, chemical and biochemical analysis was carried out, the coefficient of energy value, the meat-and-bone quality index and the calorific value of the broiler chicken meat of the control and experimental groups were calculated.

Results. Experimental results on the effectiveness of the rational dose of the complex fodder probiotic supplement are presented on the basis of the functional mixture of Bifidobacterium pullorum, Lactobacillus plantarum, L. paracasei ssp.bacteria. Paracasei and L. rhamnosus for broiler chickens.It was found that with the use of a probiotic composite, the live weight of broiler chickens of the experimental group increased by 6.8%, the average daily gain increased by 6.9 %, safety by 3.2%, the productivity index increased by 37.7 units compared to the control. It was found that the content of protein and ash in carcasses and parts thereof as a result of the use of a functional additive increased, and the moisture and fat content, on the contrary, decreased.

Сonclusions. It has been proved that the use of a complex fodder probiotic based on lacto- and bifidobacteria significantly improves the quality of production of broiler chickens under production conditions. The obtained results on a production scale and conditions confirm the effectiveness of the introduction of a complex probiotic for agricultural birds developed on the broiler chickens model, are the basis for further research and implementation in large-scale production, and also open prospects for its use for Galliformes taxon birds, including meat and ornamental breeds.

Antibacterial Properties of Some Macromycetes

Наукові вісті - Птн, 06/23/2017 - 00:00

Background. The constant emergence of pathogen forms and their new species multi-resistant to existing drugs, and the frequent occurrence of side effects of these drugs cause need to find new antibiotic compounds, especially anti­biotics of natural origin (from plants, fungi, mosses). Fungi are promising object of research because of pro­duction of various biologically active substances.

Objective. The aim of the paper is to analyze the results of research of antibacterial properties of various macromycetes representatives and determine prospects of their practical application.

Methods. The analysis and generalisation of information about objects and methods of macromycetes antibacterial activity research.

Results. Much attention is paid to Basidiomycetes among macromycetes, especially species of the genus Agaricus, Ganoderma, Lentinus, Phellinus, Pleurotus, Polyporus, Trametes. In practice macromycetes are used both as fruiting bodies, biomass and culture liquid and as isolated antibiotic substances. Therefore, edible species of fungi are preferred (Agaricus sp., Pleurotus sp. and Lentinus sp.).

Conclusions. Considering the diversification of investigations dedicated to the search for antibacterial properties of fungi, obtained data on antibiotic activity are quite hard to generalize. Studying of antibacterial activity, action mechanisms is especially important and promising research direction of antibacterial compounds found in macromycetes for further implementation of antibiotics and/or components based on culture liquid, mycelium and fruiting bodies of fungi.

The Effect of Lactic Acid Bacteria and Bifidobacteria on the Number of Natural Killer Cells in Normal Conditions and in Cases of Intravaginal Staphylococcosis in Mice

Наукові вісті - Птн, 06/23/2017 - 00:00

Background. Development of new immunobiotics based on commensal nonpathogenic probiotic bacteria such as lactic acid bacteria and bifidobacteria with antibacterial and immunomodulatory effects is an important area of modern biotechnology.

Оbjective. The aim of this study was to determine the effect of Lactobacillus acidophilus IMV B-7279, L. casei IMV B-7280, L. delbrueckii subsp. bulgaricus ІМV В-7281, Bifidobacterium animalis VKL and B. animalis VKB (individually) or their different compositions on the number of natural killer cells (NKC) in the spleen of BALB/c mice at normal conditions and in the case of the experimental intravaginal staphylococcosis.

Methods. The number of NKC in the spleen was studied using monoclonal phycoerythrin-conjugated antibodies against NKC antigens (MACS, Miltenyi Biotec, Germany). Calculations of NKC as well as analysis of the results were performed using flow cytometry method on a FACStar Plus cytofluorometer.

Results. It is shown that the number of NKC in the spleen of intact mice did not change under the influence of L. acidophilus ІМV В-7279, L. casei ІМV В-7280, B. animalis VKL or B. animalis VKB (individually). But, using L. acido­philus ІМV В-7279, L. casei ІМV В-7280, L. delbrueckii subsp. bulgaricus ІМV В-7281, B. animalis VKL and B. ani­malis VKB (individually) or their different compositions for colonization of the vagina in the case of intravaginal staphylococcosis associated with increasing of the number of NKC in spleen in different periods of observation. The number of NKC in the spleen of staphylococcus-infected mice completely normalized after treatment with some probiotic compositions. The probiotic bacteria (individually) only partially normalized the number of NKC in the spleen of staphylococcus-infected mice.

Conclusions. Thus, L. acidophilus ІМV В-7279, L. casei ІМV В-7280, L. delbrueckii subsp. bulgaricus ІМV В-7281 or B. animalis VKL (individually) or their various compositions are promising to create highly effective immunobiotics, that are able to increase the innate immunity in cases of infections.

Risk Assessment of Technology of Preparation Based on Recombinant Human Interleukin-7 and Its Perspective Validation

Наукові вісті - Птн, 06/23/2017 - 00:00

Background. Quality management is a very important activity of any industrial enterprise, especially when it comes to manufacturing products in health care (drugs, including medical immunobiological preparations, medical devices, cosmetics, dietary supplements, etc.). Risk-oriented thinking enables an organization to identify factors that may cause rejection of its processes and its quality management system for planned results to establish preventive controls to minimize negative impacts and the greatest possible shaft advantage of the opportunities as they arise. The logical continuation of the risk assessment is validation processes. This article is a fragment of the complex scientific and technical work on the development and standardization of biotechnology products based on recombinant human interleukin-7 (rhIL-7).

Objective. Justification for approaches to risk assessment in the technology for getting preparation based on rhIL-7 in the form of nasal spray and particularly risk assessment of the production process, and perspective validation of developed technologies.

Methods. The methodology of risk assessment according to ISO 14971:2009 “Medical devices. Guidelines for risk management” was used. Pharmacopoeial methods were used to control the process and product quality (potentiometric determination of pH, osmolality, sterility). The integrity of the filters was determined by the method according to the manometer producer.

Results. The work consistently study approaches to risk assessment in the technology for getting preparation based on rhIL-7 in the form of nasal spray and particularly risk assessment of the production process, and the validation of promising technologies developed. Selection of guidelines on risk assessment was conducted for Guidelines for Good Manufacturing Practices, ISO 9001:2015, ISO 13485:2005, and ISO 14971:2009. The greater acceptability of the use of the past two standards was showed. Technological production scheme is presented and qualitative approach to analyze the identified risks is applied. For the most critical stage of production (preparation of sterile solution) the validation process is conducted.

Conclusions. The feasibility of risk assessment in the technology for getting preparation based on rhIL-7 in the form of nasal spray according to ISO 14971:2009 together with the system using risk analysis and critical control points is theoretically justified. It was found that the most critical step in the production is part of the preparation of a sterile solution, which includes the preparation of intermediate filtering and sterilizing drug. The conducted prospective validation of the most critical stages of the technology demonstrated its stability and compliance with established eligibility criteria.

Transient Expression of Recombinant Small Interfering RNA to mRNA of \[\delta-Isoform\] Human Protein Kinase C in Lactuca Sativa Biomass

Наукові вісті - Птн, 06/23/2017 - 00:00

Background. The perspective of research of small interfering RNA (siRNA) application in medical practice was proved by its efficiency of chemically synthesized siRNA in the experiment in vitro. The high cost of RNA production through chemical synthesis determines the importance of searching the biotechnological methods of obtaining these compounds. A promising area of biopharmaceuticals creation is a combination of active pharmaceutical substances with innovative tools of delivery, such as bio-encapsulation in plant cells.

Objective.The aim of the paper is testing of capabilities and efficiency of transient expression of the gene encoding the small interfering RNA to mRNA

\[\delta-isoform\]

 of human protein kinase C \[(anti-PKC\delta)\] in edible raw plant biomass of lettuce Lactuca sativa.

Methods. Obtaining the biomass which accumulates anti-PKCd small interfering RNA molecules was carried out by the method that was developed by our research group for the expression of genes encoding recombinant proteins. Evaluation of small interfering RNA accumulation was performed by a reverse transcription method with the subsequent Real-Time Polymerase Chain Reaction (PCR).

Results. The level of accumulation of target product is 22 fmol/g of lyophilized plant biomass.

Conclusions. The method of transient expression allows obtaining the lettuce Lactuca sativa biomass, which contains small interfering RNA recombinant anti-PKCd (detected by a reverse transcription method with the subsequent Real-Time PCR).

New Biosurfactants of Culture Pseudomonas Aureofaciens NB-1

Наукові вісті - Птн, 06/23/2017 - 00:00

Background. Important problems of technologies of biosurfactants production are the search for active strain-producers, optimization of their biosynthesis, as well as elaboration of effective methods of biosurfactants isolation from cultural liquid after fermentation.

Objective. The influence of extractants to release surfactant lipids from the supernatant of cultural liquid of the strain P. aureofaciens NB-1 and investigation of their ability to use for protection of the steel against corrosion.

Methods. Surfactants were isolated by extraction of various solvents and their mixtures, their composition and weight were analyzed. The effectiveness of corrosion inhibition was analyzed by corrosion rate of steel plates.

Results. Microorganisms of strain P. aureofaciens NB-1 synthesize extracellular biosurfactants of rhamnolipid and lipopeptid nature. It was shown that at pH 11, biosurfactants yield using ethylacetate and isopropanol (2:1) was 3.71 g/L, exceeding their output at pH 3 to 54 %. The efficacy of using the supernatant of cultural liquid P. aureofaciens NB-1 (dilution 1:10) for corrosion protection of St3 steel in aggressive medium was shown.

Conclusions. The methods of optimal isolation of surfactant of P. aureofaciens NB-1by the selection solvents and control of pH indicators were elaborated. As a result the synthesis parameters were significantly increased. It was shown that obtained product is perspective as inhibitor of metal corrosion. 

The Critical Temperature Maximum Limit for Basidiomycetes Laetiporus sulphureus

Наукові вісті - Птн, 06/23/2017 - 00:00

Background. Today we can observe an increased attention to the usage of various drugs based on Laetiporus sulphu­reus. However, most part of the literature pays attention to pharmacological properties of the products, but the issue of cultivation and storage of museum culture is insufficiently studied.

Objective. The aim of the paper is to determine the critical temperature of fungal growth, which is an important indicator for keeping the most productive crop strains.

Methods. The study was conducted on 14 strains of Laetiporus sulphureus. Cultivation was carried out for 3 days on the medium with wort agar for temperature control – 35–37 °С.

Results. The survey defined the upper limit of the critical temperature of growth for most strains.

Conclusions. The obtained data indicate that 37 °С temperature for most strains of the fungi  Laetiporus sulphureus is critical, but strains 1518, 1776, 1815 retain poor growth at this temperature that provides the basis for further researches.

Development of Conditions of Submerged Biosynthesis of Landomycin A

Наукові вісті - Птн, 06/23/2017 - 00:00

Background. Development of the process and biotechnology of production of antitumor antibiotic with microbial origin – landomycin A.

Objective. Establishment of the rational parameters for the submerged biosynthesis of landomycin A during the cultivation in the laboratory conditions.

Methods. Cultivation of the producer Streptomyces cyanogenus S136 was performed on shaking devices in the flasks. Antibiotic was extracted from culture fluid with ethyl acetate; the content of antibiotic was determined by measuring optical density of the extract.

Results. Conditions and parameters for antibiotic submerged biosynthesis of the landomycin A by S. cyanogenus S136 were investigated. Alternative nutrient mediums for the biosynthesis of the landomycin A were presented. Mediums that are based on soybean’s flour extract and corn’s flour allow obtaining up to 80 mg/ml of antibiotic. The influence of mixing intensity and temperature on the rate of the product accumulation and its dynamics was established. Rational technological parameters of the producer’s submerged biosynthesis such as temperature 25 ± 1 °С mixing intensity 230–250 U/min, duration of the submerged fermentation 50–60 hours were established.

Conclusions. Variants of the culture media, that were selected (based on the corn’s flour and the extract of the soybean’s flour) and the parameters of the landomycin A biosynthesis, that were set are the basis for optimization and design of the technology for obtaining the antibiotic in industrial conditions.

Antimicrobial Action of Compositions Based on Thiosulfonates and Biosurfactants on Phytopathogens

Наукові вісті - Птн, 06/23/2017 - 00:00

Background. The development of environmentally safe preparations with antimicrobial activity on microorganism-phytopathogens.

Objective. Determination of antimicrobial activity of compositions alilthiosulfonate (ATS) and metylthiosulfonate (MTS) with surface-active rhamnolipid biocomplex (RBC) on phytopathogens Agrobacterium tumefaciens and Сlavibacter michiganensis.

Methods. Investigation in vitro of antimicrobial activity of compositions based on thiosulfonates and rhamnolipid biocomplex on microorganism-phytopathogens A. tumefaciens and C. michiganensis in accordance with the minimum inhibitory concentration and minimum bactericidic concentrations of developed compositions. Studies of biosurfactant effect on permeability of cell membraines.

Results. It is shown that the composition of methyl- and alilthiosulfanilates with RBC are more activе and have lower values of minimum inhibitory and bactericidic concentrations than ATS and MTS alone – on average by 50 %.

Conclusions. The results showed the prospects of rhamnolipid-biosurfactants use for creation of highly effective compositions with biocides for plant protection.

Reception of Nanostructured Materials Based on Illite for Toxic Substances Immobilization

Наукові вісті - Птн, 06/23/2017 - 00:00

Background. Using natural clay sorbents on a wide scale, one of the issues that need further development is the issue of used sorbents utilization. From an economic point of view regeneration is inappropriate. Therefore, one of the most suitable methods of waste silica sorbents disposal is their high temperature processing.

Objective. Establishing of cobalt ions immobilization in the structure of sorbents based on illite and determination of the optimal heat treatment conditions for the formation of nanostructured materials with improved physicomechanical properties and resistance to leaching.

Methods. Refining of illite structural transformation features during heat treatment by NMR spectroscopy and XRD, research of the conditions for obtaining crystallization structures in heat-treated illitic sorbents samples and establishing the relationship between their structure and physicochemical and mechanical properties.

Results. The features of illite structural transformations during heat treatment have been investigated, the mechanism of toxic ions (Со2+) fixation in nanostructured matrix has been determined. Physicomechanical (density, open porosity, water absorption, ultimate tensile strength in compression) and physicochemical (resistance to aggressive leaching reagents) properties of illitic waste sorbents treated at different temperatures have been investigated.

Conclusions. With increasing the temperature of heat treatment aluminum atoms in the structure of illite are moving from octahedral to tetrahedral coordination, which is accompanied by the formation of three-dimensional nanostructured framework that provides a strong fixation of toxicant ions. It was found that the optimum temperature for heat treatment of illite is 900 °C, which produced nanostructured materials with optimal physicomechanical and physicochemical properties.

Defluorination of Water by the “Inline” Coagulation–Ultrafiltration Method

Наукові вісті - Птн, 06/23/2017 - 00:00

Background. The various methods used for water defluorination (sedimentation, coagulation, ion exchange, etc.) cannot be used at high (>10 mg/dm3) content of fluorides. Therefore, the development of new high-performance methods of water purification from ions of F- is extremely important and relevant.

Objective. Determination of the effectiveness of the process of water defluorination by “inline” coagulation–UF method.

Methods. Dosing of coagulant into a stream of “inline” water, followed by using the ultrafiltration method with domestic tubular ceramic membranes from clay minerals.

Results. The influence of duration of process, the initial concentration of the ions F- and Fе3+ in solution and its pH on the concentration of ions F- in permeate and specific performance of the Jv of the membrane has been investigated. It is shown that for water defluorination with the concentration of the starting solution F- value of 5.0–10.5 mg/dm3 and Fе3+ = 17,0–32,0 mg/dm3, with рН 3,0–3,5 and P = 1.0 MPa the concentration of ions F- and Fе3+ permeate was at the level of their MCL in drinking water.

Conclusions. The high efficiency of water defluorination by “inline” coagulation–UF method using coagulant FeCl3∙6H2O has been shown. The parameters of the specified process by which water purification from ions of F- and Fe3+ to norms of maximum permissible concentration in drinking water are determined. The expediency of using the method for water defluorination in an acidic medium followed by its neutralization is justified. 

Comparative Characteristics of Physical, Chemical, and Biochemical Methods for Determining Nitrofuran Metabolites in Food

Наукові вісті - Птн, 06/23/2017 - 00:00

Background. Nitrofurans belong to a class of synthetic antibiotics, which are widely used in various livestock sectors due to their high effectiveness in control over infectious diseases and as a growth activator. Nitrofurans are rapidly metabolized compounds, but the metabolites of these drugs are able to bind to protein structures and accumulate in the body of animals. Nitrofuran metabolites show carcinogenic properties, therefore it is necessary to control their content in food products of animal origin.

Objective. The aim of the paper is to summarise modern methods for nitrofurans analysis.

Methods. The modern methods of sample preparation of food products of animal origin for extracting nitrofuran metabolites and methods for detecting these analytes are systematized and analyzed.

Results. Modern analysis methods have a sufficient sensitivity level of nitrofurans determination in the form of final products – furaltadone and furazolidone metabolites. There are several methods of detection, among which are chro­matographic methods and enzyme immunoassay.

Conclusions. Analysis of the literature has shown that use of combined techniques combining selective removal of nitrofuran metabolites from the sample matrix and their quantification, allows screening and confirmatory test for the presence of nitrofurans in food and also allows detecting analytes at 1 mg/kg.

Influence of Electrokinetic Phenomena on the Mass Transfer of Electrofiltration Disinfection of Water

Наукові вісті - Птн, 06/23/2017 - 00:00

Вackground. The development of a method for increasing the efficiency of an installation for electrochemical water disinfection.

Оbjective. The aim of the paper is the study of the influence of electrokinetic phenomena on the mass transfer in a system with a charged porous diaphragm, aimed at determining the conditions that allow increasing the efficiency of the process of electrofiltration water disinfection while maintaining the parameters of its conduct and ensuring the necessary degree of decontamination.

Methods. The determination of the efficiency of the microporous filter element in various ways of organizing the electrofiltration process is conducted.

Results. The efficiency of the microporous charged element depends on the location of the cathode and the anode, which determines the direction of the electroosmosis with respect to the flow of the treated water. Increasing the strength of the electric field while maintaining the value of the operating pressure leads to an intensification of the processes affecting the efficiency.

Conclusions. The location of electrodes, which ensures the counter motion of the hydrodynamic flow of the treated water and the electroosmotic flow occurring in the pores of the charged diaphragm, allows substantially increasing the productivity of the disinfection process.

Stress concentration in nonlinear viscoelastic composites

Машинобудування - Чтв, 06/22/2017 - 00:00
A nonlinear viscoelastic problem of the mechanics of composites is solved within the framework of a second-order nonlinear theory. A viscoelastic functional is used to construct general defining relations. A stochastic boundary value problem for determining the stress concentration and its relaxation in polymer composite materials (PCM) is solved. To derive the complete system of second-order viscoelastic equations, the method of successive approximation is used. A generalization of the correspondence principle to nonlinear viscoelastic media is obtained. The relaxation functions averaged over the viscoelastic matrix and elastic inclusions and the stress concentration parameters are determined. Examples are given showing the importance of the mutual influence of nonlinear elastic and viscous properties of the components on stress redistribution near inclusions in multicomponent PCMs. As a practical result, one can note the possibility of predicting the long-term strength of a material when a viscoelastic stress field is known near inclusions.

Static calculation of the “Spindle unit” elastic system by using transfer matrices method

Машинобудування - Чтв, 06/22/2017 - 00:00
Abstract. Methodology, that allows to use the transfer matrices method for the static calculation of spindle unit as elastic system, which consists of a few associate subsystems, has been developed. Restrictions of the dynamic compliances method use for static calculations of «spindle unit» system decomposing has been stated. For such calculations it is suggested to conduct the decoupling of the system with the use of mixed method of indefinable beam systems static calculation. The elastically-deformation model of the «Spindle unit» system, that consist of subsystems: tool, spindle, spindle housing elastically mounted on the machine-tool bed, is being presented. The scheme of decoupling of this system for static calculations has been developed. The analytical solution of task of the elastic displacements calculation in the characteristic points of subsystems has been obtained. The algorithm of static calculation of the «Spindle unit» elastic system has been developed. Offered approach allows applying an identical methodological base for the static and dynamic characteristics simulation of the «Spindle unit» elastic system.

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