A trace formula and high energy spectral asymptotics for the perturbed Landau Hamiltonian

A two-dimensional Schr\"odinger operator with a constant magnetic field perturbed by a smooth compactly supported potential is considered. The spectrum of this operator consists of eigenvalues which accumulate to the Landau levels. We call the set of eigenvalues near the $n$'th Landau level an $n$'th eigenvalue cluster, and study the distribution of eigenvalues in the $n$'th cluster as $n\to\infty$. A complete asymptotic expansion for the eigenvalue moments in the $n$'th cluster is obtained and some coefficients of this expansion are computed. A trace formula involving the first eigenvalue moments is obtained.Comment: 23 page

Corrosion inhibitors for steel oilfield equipment

© 2017 Institute of Thermomechanics CAS, v.v.i.The rate of corrosion and protection of steel are determined as a test environment using the model which produces water with the addition of inhibitors or corrosion inhibitors (CaCl2·6H2O, MgCl2·6H2O, NaCl, CaSO4·2H2O). The proposed steel protection "Steel 20" was 77.8 % in comparison to the same conditions conducted for tests of commercially available corrosion inhibitors. The protective properties of the proposed corrosion inhibitor are not inferior with respect to the currently used inhibitors

Effect of the pH of emulsion on ultrafiltration of oil products and nonionic surfactants

© 2017, Pleiades Publishing, Ltd. The structure and properties of a water–oil emulsion have been studied. The ultrafiltration of the water–oil emulsion has been performed with the use of spiral wound and hollow fiber membranes to separate the emulsion into a filtrate and a concentrate. The effect of pH on the following performance characteristics of the ultrafiltration process has been studied: the efficiency and the degree of separation of oil products and nonionic surfactants. It was found that an increase in the pH value of the emulsion decreased the efficiency of membranes and the degree of separation of nonionic surfactants. It has been found that a Raifil UF membrane effectively rejects oil products from acidic emulsion and, on the contrary, an EMU 45-300 membrane is effective in an alkaline medium. This behavior has been associated with to a positive surface charge of the EMU 45-300 membrane. The maximum efficiencies and degrees of separation of oil products and nonionic surfactants from emulsions with the use of the Raifil UF ultrafiltration membrane and the EMU 45-300 membrane have been attained in the pH ranges from 2.1 to 2.9 and from 2.2 to 2.5, respectively. After ultrafiltration, the size of particles in the filtrate increased by a factor of about 18 due to the coalescence of oil particles in the near-membrane layer because of polarization effects. The increase in the particle size of the dispersed phase in the filtrate can also be explained by a positive surface charge of polysulfonamide membranes

Effect of temperaturje and pH value of the liquid shared selectivity cation exchange membrane, nylon-PANI

Ion-exchange membranes are widely used in modern technologies, especially in the field of water treatment, substantially reducing the cost of processing waste water and to ensure their high degree of purification. The ion-exchange processes in membranes affected by various external factors, the most important of which are temperature, pH and salinity, initial solution. The aim of the research is the study of factors affecting selectivity of ion exchange membranes, and the determination of the optimal temperature and pH ranges shared the liquid water purification processes of metal ions using modified polyaniline had fulfilled (PANI) nylon membranes. In this paper, these are composite membrane with modified surface layer of silver nanoparticles on the surface of nylon. Experiments were conducted to determine the effect of temperature and pH on membrane selectivity nylon-PANI. Temperature coefficients were obtained for nylon membranes-PANI of heavy metal ion on changing selectivity membranes with temperature at 1° C

Investigation of the properties and composition of a concentrate of spent Inkam-1 emulsion as a corrosion inhibitor

© 2017, Pleiades Publishing, Ltd. The processing of discharge cutting fluids by membrane methods yields a concentrate consisting of petroleum products and surfactants. A gas chromatography–mass spectrometry study of the chemical composition has revealed the presence in the concentrate of dicyclohexylamine, which is a corrosion inhibitor according to published data. Therefore, it has been proposed to use the concentrate as a steel corrosion inhibitor for oilfield equipment. The physicochemical properties of the inhibitor have been determined, and corrosion tests for steel of Steel 20 grade have been carried out using the gravimetric method. To improve the protective properties of the inhibitor, the spent-coolant concentrate has been treated with a 1 M NaOH solution (to increase the pH) and modified by admixing oxypropylated diethylene glycol. According to the testing data, the degree of protection of Steel 20 was 78.5%. The resulting concentrate can be used as an inhibitor to protect pipelines against the corrosive effects of formation water. The composition of additives that can enhance the inhibitory characteristics of the concentrate has also been determined by testing

Utilization of waste lubricating-cooling fluids by membrane methods

© 2015 Springer Science+Business Media New York. Utilization of waste lubricating-cooling fluids (LCF) cleaned preliminarily by membrane methods is investigated and, based on results of the investigation, an LCF utilization scheme is proposed. The scheme includes the following cleaning stages: coalescence, adsorption, ultrafiltration, nanofiltration, and ion exchange. The first stage is intended for preliminary removal of oil products and suspended matter from the LCF by thin-layer coalescence on polymer plates. In the ultrafiltration stage, oil products, surfactants, and suspended matter are removed by a composite carbon sorbent. Oil products, surfactants, fats, etc. are completely removed, and the mineral content of the water is reduce by roll ultra-nanofiltration membrane elements, and heavy metals are removed from the nanofiltrate by ion-exchange membranes. After the last stage, the cleaned water meets the standards of effluents to be discharged into a drainage system. The overall degree of removal of suspended matter, oil products, surfactants, fats, etc. is 99 % at the outlet

Investigação das propriedades físico-químicas e características estruturais do produto da pirólise de resíduos de madeira

In this paper, the object of investigation is a solid product of pyrolysis of wood waste. The structural characteristics and physical-chemical properties of the solid pyrolysis product obtained in the production conditions, characterizing the sorption properties with respect to pollutants contained in aqueous media - the specific area, surface structure, pore size and size distribution are characterized.The specific surface, volume and radius of the pores were determined by capillary condensation of nitrogen. The specific surface area of the pyrolysis product of wood waste is 310.5 m2/ g. The volume and radius of the pores determined by the t-method and the BJH method are 0.229 cc/g and 19.3 A, respectively. The elemental composition and surface structure of the pyrolysis product were studied by scanning electron and x-ray microscopy. The obtained data indicate the presence of sorption properties.According to the definition of the dispersed composition, the pyrolysis product of wood waste mainly contains particles of sizes from 0.1 to 3 mm (86.6%). The specific value of the bulk density of the pyrolysis product is not inferior to that of known adsorbents. And they are 295 g/dm3. The moisture content of wood waste after treatment with pyrolysis does not exceed the normative value and accounts for 2.7%.It is established that utilization of wood waste by low-temperature pyrolysis makes it possible to obtain a sorption material.En este trabajo, el objeto de investigación es un producto sólido de pirólisis de residuos de madera. Se caracterizan las características estructurales y las propiedades físico-químicas del producto de pirólisis sólido obtenido en las condiciones de producción, que caracterizan las propiedades de sorción con respecto a los contaminantes contenidos en medios acuosos: el área específica, la estructura de la superficie, el tamaño de los poros y la distribución de tamaños.La superficie específica, el volumen y el radio de los poros se determinaron mediante la condensación capilar de nitrógeno. El área superficial específica del producto de pirólisis de los residuos de madera es de 310,5 m2 / g. El volumen y el radio de los poros determinados por el método t y el método BJH son 0.229 cc / gy 19.3 A, respectivamente. La composición elemental y la estructura de la superficie del producto de pirólisis se estudiaron mediante microscopía electrónica y de rayos X de barrido. Los datos obtenidos indican la presencia de propiedades de sorción.Según la definición de la composición dispersa, el producto de pirólisis de los desechos de madera contiene principalmente partículas de tamaños de 0,1 a 3 mm (86,6%). El valor específico de la densidad aparente del producto de pirólisis no es inferior al de los adsorbentes conocidos. Y son 295 g / dm3. El contenido de humedad de los residuos de madera después del tratamiento con pirólisis no excede el valor normativo y representa el 2,7%.Se ha establecido que la utilización de residuos de madera mediante pirólisis a baja temperatura permite obtener un material de sorción.Neste trabalho, o objeto de investigação é um produto sólido de pirólise de resíduos de madeira. As características estruturais e propriedades físico-químicas do produto de pirólise sólido obtido nas condições de produção, caracterizando as propriedades de sorção em relação aos poluentes contidos em meio aquoso - a área específica, estrutura superficial, tamanho de poro e distribuição de tamanho são caracterizadas.A superfície específica, volume e raio dos poros foram determinados por condensação capilar de nitrogênio. A área superficial específica do produto da pirólise de resíduos de madeira é de 310,5 m2 / g. O volume e o raio dos poros determinados pelo método t e pelo método BJH são de 0,229 cc / ge 19,3 A, respectivamente. A composição elementar e a estrutura superficial do produto da pirólise foram estudadas por microscopia eletrônica de varredura e de raios-X. Os dados obtidos indicam a presença de propriedades de sorção.De acordo com a definição da composição dispersa, o produto de pirólise de resíduos de madeira contém principalmente partículas de tamanhos de 0,1 a 3 mm (86,6%). O valor específico da densidade aparente do produto de pirólise não é inferior ao dos adsorventes conhecidos. E eles são 295 g / dm3. O teor de umidade dos resíduos de madeira após o tratamento com pirólise não excede o valor normativo e representa 2,7%.Estabelece-se que a utilização de resíduos de madeira por pirólise a baixa temperatura possibilita a obtenção de um material de sorção

Particle size and zeta potential changes in the disperse phase of water-emulsified waste waters in different treatment stages

© 2015 Springer Science+Business Media New York. We have studied the colloidal properties of stable highly disperse emulsions: fresh and waste lubricant/liquid coolant (LLC) and water-emulsified waste waters. The fresh LLC is monodisperse and the particle size of the disperse phase is equal to 0.086 μm. The particle size for the disperse phase of the waste LLC is 0.05-0.15 μm. We have identified the trends in the variation in colloidal properties of the waste LLC during treatment in different stages: coalescence treatment, sorption of petroleum products by a composite sorbent, ultrafiltration, nanofiltration, final purification on an ion-exchange membrane. After the membrane treatment methods, the average particle size increases and the absolute value of the zeta potential decreases due to breaking of the emulsion; the particles instantaneously become larger due to loss of charge while passing through the pores of the membranes

Removal of oil products and phenol from waste water by composite sorbents under dynamic conditons

Sorption removal of petroleum products and organic pollutants is one of the most efficient methods of cleaning waste water. A high degree of removal with easy regeneration of the sorbent is achieved when porous fluoroplastic is used as the sorbent. In this study, we obtained composite sorbents from porous fluoroplastic and studied their filtration properties with respect to hydrocarbons and phenol in waste water. These sorbents possess a higher phenol-sorption capacity until break-through than activated carbon. The phenol-sorption capacity depends linearly on the carbon content in the composite sorbent, and the hydrocarbons are sorbed by both the carbon and fluoroplastic. An important advantage of the composite sorbents over activated carbon is that they can be repeatedly regenerated. © 2014 Springer Science, Business Media New York

Modified PTFE–PANI membranes for the recovery of oil products from aqueous oil emulsions

© 2017, Pleiades Publishing, Ltd.Composite membranes have been prepared by modifying a polytetrafluoroethylene membrane with aniline hydrochloride, and the effect of polymerization time on the efficiency of the recovery of petroleum products from aqueous oil emulsions was studied. It has been found that the modification leads to an increase in the degree of oil removal from oil-in-water emulsions by 29%. The specific productivity of the original and modified membranes has been determined with distilled water and water–oil emulsions. It has been found that the specific productivity of the membranes decreases with the time of membrane treatment with ammonium persulfate. The surface of the modified membranes has been studied with the aid of a scanning electron microscope, and the elemental composition of composite membrane surfaces has been examined by X-ray fluorescence analysis. It has been determined that the modification of a polytetrafluoroethylene membrane with aniline hydrochloride leads to an increase in the carbon content and the appearance of nitrogen, oxygen, and sulfur atoms