Home – Home – Jornals – Chemistry for Sustainable Development 2017 number 5

The problems and the possibility of using diffractive elements with a sawtooth relief-phase microstructure in imaging optical systems are analyzed. Particular attention is paid to minimizing the negative adverse effect of diffraction orders on the quality of the image formed by an optical system with a diffractive element due to the transition from single-layer microstructures to structure containing several layers and reliefs. Requirements to the design parameters of the microstructure and operating conditions of the diffractive element in the optical system are formulated that ensure the absence of the visually observable halo due to adverse diffraction orders. A number of examples have shown that incorporation of a diffractive element in a plastic-lens imaging optical system corrects chromatic aberration and provides high resolution in the generated image.

This paper considers the features of the surface structure shapes of multifocal intraocular lenses (IOLs) which, unlike bifocal IOLs form additional foci or increase the depth of focus, which provides good vision not only near and far but also at intermediate distances. The field of clear vision is achieved on the basis of the effects of diffraction, interference, and refraction (change in the radius of curvature of the lens surface). The optical characteristics of the best-known multifocal IOLs (trifocal and quadrifocal lenses and lenses with an extended focal region) are given.

Manufacturing processes and design features of modern diffractive-refractive intraocular lenses are presented. The implantation of multifocal intraocular lenses is the most optimal method of restoring the accommodative function lost after removal of the lens. Diffractive-refractive intraocular lenses are the most widely used implantable multifocal lenses worldwide. Existing methods for manufacturing such lenses implement various design solutions to achieve the best visual measures after surgery. The variety of modern designs of diffractive-refractive Intraocular lenses reflects the demand for this method of vision correction in clinical practice and the importance of further applied research and the development of new technology solutions to design improved lens models.

An improved method of structural lighting for increasing the efficiency of inspection of the cylindrical object surface appearance is considered. The method is based on using a diffractive optical element to reduce the amount of recorded data due to illuminating the test object at an angle to the image recording plane, which is normal to the inspected surface. Implementation of the proposed method implies the use of several identical channels. For this reason, one channel is considered in the present study. Calculations of diffractive elements, a description of the experimental setup, and results of experiments aimed at determining the depth of surface defects on objects simulating fuel pellets and fuel elements are presented. Implementation of the investigated method with defect depth determination in industrial systems of inspection of fuel pellets and fuel elements is expected to improve the quality of the fuel for atomic power stations.

Various issues of creation of diffractive optical elements transforming one laser beam with small divergence to a matrix of converging beams with a diffraction size of focused spots in the plane of object illumination and their application for problems of DNA sequencing and microscopy are considered. The parameters of diffractive elements are calculated and optimized in the approximation of the Fresnel-Kirchhoff diffraction theory. Diffractive elements are fabricated by the method of direct laser writing on a photoresist by using a circular laser writing system. Experimental characteristics of a diffractive element creating a matrix consisting of 33 × 33 beams, which are focused in one plane at a distance of 210 mm, are presented. The degree of nonuniformity of beam intensities determined by the ratio of beam intensities in the central region to intensities of peripheral beams is 1/2.5, which is potentially sufficient to be used in DNA sequencing problems. The maximum distortions of spot positions in the entire focusing field is <0.15 %.

This paper describes a study of the optical methods of the formation of multilevel microrelief in the layers of a Gibrimer-TATS hybrid photopolymer material based on thiol-siloxane and acrylate oligomers. Halftone photolithography and direct laser recording are used to form multilevel structures 3.5 and 6 μm in height, respectively. The characteristic curves and photosensitivity of the material are determined. The process of preparation and treatment of the films is optimized, and it is discovered that the addition of the stages of pre- and post-exposure significantly affects the photosensitive properties of Gibrimer-TATS. The photopolymer is promising as a structural material for the formation of microstructured optical components.

This paper is a review of the studies carried out by the staff of the National Research University of Information Technologies, Mechanics and Optics (ITMO University, Saint-Petersburg) and the Institute of Automation and Electrometry of the Siberian Branch of the Russian Academy of Sciences (Novosibirsk) in the field of development of laser technogical processes for the formation of the structure of diffraction optical elements (DOEs) and photomasks with amplitude binary and semitone transmission. The paper also describes the results of the study of laser thermochemical technology for manufacturing chrome DOEs, technologies for the manufacture of halftone DOEs, and photomasks based on the use of amorphous silicon and LDW glass.

This paper presents a short analysis of papers devoted to the nonparaxial effects arising from the use of the lensacon proposed by Koronkevich with coworkers in 1993, as well as its analogs in a substantially nonparaxial mode. In this case, accounting for the vector character of electromagnetic radiation is required, allowing new effects to be detected, which, in turn, provides an additional impetus to expand the range of applications of the lensacon.

Results of investigations of diffraction phenomena on constant-thickness three-dimensional objects with plane internal surfaces (thick plates) are summarized on the basis of our constructive theory of their calculation as applied to dimensional inspection. It is based on diffraction models of 3D objects with the use of equivalent diaphragms (distributions), which allows the Kirchhoff-Fresnel approximation to be effectively used. In contrast to available rigorous and approximate methods, the present approach does not require cumbersome calculations; it is a clearly arranged method, which ensures sufficient accuracy for engineering applications. It is found that the fundamental diffraction parameter for 3D objects of constant thickness d is the critical diffraction angle _кр = √/ d at which the effect of three-dimensionality on the spectrum of the 3D object becomes appreciable. Calculated Fraunhofer diffraction patterns (spectra) and images of constant-thickness 3D objects with absolutely absorbing, absolutely reflecting, and gray internal faces are presented. It is demonstrated that selection of 3D object fragments can be performed by choosing an appropriate configuration of the wave illuminating the object (plane normal or oblique waves, spherical waves).

A comparative analysis of spatial variations in the energy characteristics of longitudinally polarized, extremely focused, needle laser beams generated by an optical system with selective thin-film transformation of the linear polarization of the beams into the radial one, followed by their subsequent spatial filtering and sharp ring focusing to subwave sizes. For the important special case of ideal radial polarization of a focused beam, longitudinal sections of spatial distributions of the electric energy density and the Poynting vector modulus in the vicinity of the focus were compared by numerical simulation. It is shown that the degree of their difference increases substantially with decreasing angular zone of ring focusing and with the introduction of space-frequency filtering. It is established that the dimensions of the axial zone of beam focusing determined for their central lobes in the first approximation do not depend on the energy characteristics in which they are measured.

This paper describes the development and manufacture of diffraction corrector and simulator for the interferometric control of the surface shape of the 6-m main mirror of the Big Azimuthal Telescope of the Russian Academy of Sciences. The effect of errors in manufacture and adjustment on the quality of the measurement wavefront is studied. The corrector is controlled with the use of an off-axis diffraction simulator operating in a reflection mode. The measured error is smaller than 0.0138λ(RMS).

This paper describes the interferometric method for controlling the assembly quality of a three-lens unit of an optical system of a non-centered nine-component optical system of an aircraft helmet wide-angle display collimator. It is shown that this adjustment method makes it possible to establish optical components, including the off-center aspherical lens, with an error of one micron. The method is contactless and allows for the control of the position of lenses inside the body of the device.

A review of advanced equipment for automated interference measurements developed at the All-Russian Research Institute for Optical and PHysical Measurements is given. Three types of interference microscopes based on the Linnik, Twyman-Green, and Fizeau interferometers with the use of the phase stepping method are presented.

On the basis of long-term (1995-2010 and 2013-2014) microbiological monitoring of the various water areas of the Volga Delta and perch pelagic predator, four dominant groups of bacteria Enterobacteriaceae, pp. Aeromonаs, Flavo, Pseudomonаs were identified. Summarizing results of studies of species composition of microflora of water and fish from natural populations and artificial breeding are given. It was established that conditionally pathogenic microflora in the water and fish prevailed over the indicator one. The role of water temperature governing the seasonal cycles of microorganisms and pathogenicity factors that determine their fast adaptation to living in different ecological niches is shown.

The article presents physical modeling of geomechanical processes in outer zones of coal beds with the main roof caveable with difficulty. The scope of the modeling embrace the effect exerted on gas release by gas temperature and pressure variation during stage-wise outlet of gas from a pressure bomb, which simulates cyclical mechanical impact on a coal bed in the zones of a gas pocket. It is found that the low-frequency (2.0-4.5 Hz) attenuating vibrations generated in the main roof can induce both secondary rock mass disintegration as well as methane desorption and decomposition of gas hydrates (if present) accompanied by an increases in gas pressure and in number of gas-dynamic events in outer zones of coal beds.

The author proposes a new analytical approach to the description of statics, kinematics and dynamics of interaction between mine support and enclosing rock mass in the course of stoping. Inclusion of the static component suggests the classical construction of a probable line of fracture. The kinematic aspect means accounting for the influence of the overlying rock weight on the process of failure. The dynamics of failure during growth of mined-out area is illustrated in terms of a unit event of production heading advance. These components of the damage accumulation process in rock mass allow more accurate monitoring of destructions due to rock pressure.

Mechanisms of change in the spectra of acoustic emission in specimens of mineral coal from Kuznetsk and Pechora Basins are experimentally determined in uniaxial and triaxial (Karman scheme) compression tests. It is shown that at the pre-failure stage in a specimen under uniaxial compression, the spectrum pattern of acoustic emission changes considerably, the amplitudes of low frequencies grow while the amplitudes of high frequencies reduce. Under the Karman scheme loading of specimens, the amplitudes of the low-frequency signals grow without the decrease in the high-frequency amplitudes, which is connected with the prevented opening of fractures under the influence of the hydrostatic pressure in the horizontal plane.

The object of the numerical study is the travel of pendulum waves in a blocky medium under nonstationary impact of deep-seated charge blasting on the surface of the expansion chamber. The blocky model is simulated by a two-dimensional lattice of masses connected by elastic springs along the axes and diagonals. The displacements and velocities of the masses at different half-space points are calculated using the finite-difference method.

The article describes the theoretical and experimental research into the strength of cylindrical specimens made of layered and anisotropic geomaterials exposed to axial compression and lateral pressure. The tests used INSTRON 8802 versatile servohydraulic fatigue testing system. The experimental results are the relationships between the ultimate strength and bedding angle in specimens of an artificial material, meta-siltstone and shale. The experimental data agree well with the theoretical calculations.

Fracturing efficiency of fluids in specific mining processes depends on reliability of data on structure and state of rocks, on pre-setting the location of fracturing origin, on choice of a fluid and its injection regime, as well as on the accepted engineering solutions. Fracturing by fluids are the processes that alter properties, structure, composition and state of rocks. Investigation of such processes offers a deeper insight into the multi-phase media (earth crust) and promotes advancement in nonconventional mining technologies.

In focus of the studies is the influence exerted by the radial displacement of the hammering unit on the air distribution in the air hammer drill with the ring-shape elastic valve. The minimal allowable volume of the backstroke chamber at the frontmost position of the hammering unit when it contacts the anvil is calculated with regard to the limited maximum pressure in the impact stroke chamber at the moment of the blow. In the capacity of the air hammer drill efficiency criterion, it is suggested to use the length of the powered closure of the elastic valve, that compensates rotation of the hammering unit in the body when the radial clearance between these parts grows. The parameters of the air distribution system are estimated for all sizes of air hammer drills with the ring-shaped elastic valves.

The article presents the procedure and algorithm for selecting basic characteristics of a positive-displacement hydraulic hammering system. The procedure is based on the dimensional analysis of equations of the system, selected similarity criteria and calculations of output characteristics in the space of the similarity criteria. The program offers a user the options of setting initial parameters and characteristics of hydraulic impact systems in the form of values and constraints and, then, table values for the dimensionless characteristics to be inserted in the similarity formulas for the selection of a hydraulic impact system. For a selected system, geometry of the hammer head is calculated. The Java-based program has a graphical multi-window interface, including menu, toolbox, windows for setting parameters, and limitations, input of source data and calculated data, computation of hammer head sizes and output of plotted dynamic characteristics of limit cycles of the hydraulic system.

The review of accidents connected with explosions in gently dipping and inclined coal bed mining with mechanized equipment is presented. It is shown that the most probable cause of the explosions is inflammation of methane-and-air mixture induced by the sources of coal self-ignition in mines. The explosion wave brings burning gas in the production heading and adjacent tunnels and causes blasting of coal dust. The mechanism of coal self-ignition in edge areas in inter-panel pillars exposed to high rock pressure is described.

The complicated geology and geomechanics in Tashtagol, Sheregesh and Kaz mines induce geodynamic events during transition to deeper level mining. Mining advance from the higher stress concentration areas from the hanging wall of a fault towards the lower stress concentration areas contributes to the reduction in rockburst hazard. The use of the self-propelled equipment allows higher volume of preparatory driving per 1000 t of ore production by 10-20% as compared with the portable equipment. The mechanism of rock mass movements in deeper level stoping is revealed. High mining depth and high strength of enclosing rocks are favorable for starting extraction of ore reserves left in pillars. The combination of these factors and the efficient mining system design enable mining of blind ore bodies without backfill and allows extraction of ore reserves from pillars under the rivers and ground surface infrastructure.

The methods and means of dumping overburden at open pit coal mines in Kuzbass are reviewed. Specific features of dumping are highlighted, and the dependence of dump stability on geological conditions and physical properties of overburden is determined. The priority lines of development in the dumping technology are aimed at efficient utilization of mined-out areas in open pits and idle hydraulic fills. The issues of the environmental safety of dumping are addressed.

The article gives testing data on the effect exerted by energy impacts (ultrasonic, electrochemical and thermal) on the recovery of zirconium and rare earth elements from eudialyte concentrate to pregnant solution by acid leaching. An original installation is developed for the implementation of leaching. Based on the research findings on the kinetics of acid leaching of eudialyte concentrate and on the change in the concentrate micro-structure and phase composition, the mechanism of the influence of integrated energy impacts on the efficiency of recovery of zirconium and rare earths in pregnant solution is substantiated.

The interaction of fatty acid sodium oleate collector and higher isoalcohols in liquid phase and on the surface of separated minerals of scheelite and calcite is investigated. The research findings on monophase calcite and scheelite are presented with their X-ray patterns and IR spectra. The experimental data show the contribution of the intramolecular interactions in combinations of differently ionizable oxyhydryl collectors on the increase in the contrast between floatabilities of scheelite and calcite. The IR spectroscopy states that the maximum strength of the intramolecular hydrogen bridges between oleate and isoalcohols in the range of 300-3200 cm-1 fits with the molar ratio 2. Isoalcohols in the surface layer of scheelite neutralize hydrophilic behavior of oleate micells by means of generation of heteromolecular associates through hydrogen bridges, loosen hydtrated layer and enhance air bubble attachability; adhesion of isoalcohol drops improves floatability of scheelite; higher isoalcohols reduce flotation activity of calcite. The maximum contrast in flotation properties is observed in slimes at oleate concentrations fit the micelle formation process.

The experimental research into intensification of copper-nickel ore concentration by flotation and magnetic separation shows that pre-treatment of ore before milling by accelerated electrons results in the increased yield of - 0.071 mm size and in enhanced recovery of useful components in the concentrate. Magnetic separation improves complexity of use of mineral raw materials.

Mine water at some mineral deposits in Transbaikalia contains valued metals commercially recoverable from solutions using zeolite rocks. Experimental impregnation of metal-bearing mine water from Sherlovaya Gora and Bom-Gorphon areas with sodium and ammonium kinds of clinoptilolite rocks from Shivyrtui deposit has been carried out. In the laboratory conditions, metals adsorbed by zeolite rocks are extracted by means of displacement by concentrated ammonium salts with the further calcinations of the filtrate up to 500 °С. The metal content of the obtained cakes is conditioned by metal concentrations in solutions, by methods of impregnation and by the eluents applied. Saturation of ammonium types of zeolites with mine water solutions from the Sherlovaya Gora lake and the further extraction of adsorbed metals by ammonium acetate yields the recovery of lantanoids of 73%. The obtained results, considering multiple recycling of the sorbent, can be used in development of an efficient technology for extraction of rare earth elements from mine solutions.

The article describes features of ore reserves and development of processing technologies at Mikhailovsky MPP. New approaches to disintegration of ore and to improvement of dry magnetic separation of unoxidized ferruginous quartzite are evaluated. The scope of the discussion embraces the process of finishing magnetite concentrate, extracted from unoxidized ferruginous quartzite by wet magnetic separation, using the flotation flow chart with the closed and open circuits, as well as the reverse cation flotation of hematite concentrate from tailings of wet magnetic separation. The authors present process solutions aimed at designing energy-saving conveyor roasting machine MOK-1-592 and the technologies of production of different purpose iron ore pellets.

A Stefan problem is analyzed for the case of rock freezing during shaft sinking, It is shown that the rate of thermal diffusion in rock mass is comparable with the velocity of the boundary between different phases. The Stefan problem is solved for a single shaft using the finite difference method. The procedure for the generalization of the calculation data on thickness of an ice-and-rock shield in a single shaft for the case of many shafts is improved. The ice-and-rock shield thickness forming around freezing pipes is calculated in terms of shaft 1 in the mine of Petrikovsky Mining and Processing plant of Belaruskali.

The authors propose to assess air pollution in mining regions using the integrated instrumental monitoring, calculation and remote sensing. The algorithms for experimental data processing for the calculation and remote monitoring of snow cover pollution as a universal indicator of the pollution distribution in air are substantiated. The article presents the integrated monitoring data on the induced load in the air in the large mining industry cluster in Kuzbass.

The authors propose the approach to validation of the surveying control accuracy in safety monitoring of earth dams in terms of liquid waste receivers at mines. Based on the system structuring of types of earth dams and their elements, estimation of influence of loads and effects exerted to these structures, as well as the analysis of accident The article presents the installation meant for the determination of gas permeability of rock specimens placed in a testing cell with the adjustable axial and lateral compression. The installation includes a measurement system for the automated long-term investigation of rock permeability in accordance with the preset program. It is also possible to test specimens with a fracture filled with a propping material. The reported data of the permeability tests of porous quartz-containing material and coal demonstrate the capacity of the installation and the experimentation specificity.

The article presents the review of the current methods used in Russia and abroad to predict accidents in underground mines based on the monitoring of stresses, strains and seismic and electromagnetic events. The phenomenon of emission of submicron particles is reveled in rocks and the submicron particle emission under compression of rock specimens is modeled physically. A conclusion is drawn on the possibility of developing a new method and equipment for the prediction of accidents during underground mining.

The method of the empirical model decomposition and its application to the analysis of data obtained using a laser strain meter is described. The issues of adaptation of the method to the real data are discussed. The method enables identification of a monotone trend and a slow component of deformation process much more efficiently than the conventional techniques. The method shows reliable operation in cleaning of signals from noise and high frequencies.

The paper carried out distilling off hydrofluoric acid from model and process acid fluoride-sulphate solutions. Conditions for the most complete distilling off process of hydrofluoric acid from fluoride-sulphate solutions were determined and proposed. Fluorosulphonic acid is formed in large amounts, as demonstrated for model solutions containing hydrofluoric and sulphuric acids. Herewith, with increasing the concentration of acids, their interaction degree rises and fluorosulphonic acid is formed, as demonstrated. An increase in heating temperature of the mixture leads to a substantial increase in acidity due to HSO₃F content decrease. The larger the concentration of acids (especially, sulphuric) is, the higher heating temperatures are required to decompose HSO₃F, as established. The formation of fluorosulphonic acid may have a significant effect on the degree of distilling off hydrofluoric acid, as shown. The energetic and economic costs in processing of 1 m³ of process acid fluoride-sulphate solution are calculated with account of the initial concentration of HF of 78 g/L. Considering sulphuric acid regeneration and having excluded lime content for its neutralization, energy costs for processing of the same solution upon heating to 140 ℃ do not exceed 4500 RUB. The findings explain high solubility of lanthanide fluorides compared to their dissolution in monobasic acids, as noted in a series of papers. Our earlier observations of decreasing the concentration of fluorine determinable by potentiometric titration relatively to initially introduced one at pH correction by using sulphuric acid, unlike that with nitric or hydrochloric ones were also explained.

Distribution analysis of lithium, uranium, and arsenic in water of mineral lakes of Eastern Transbaikalia that are different by mineralization degree, macrocomponent composition, and water pH was performed. Lithium is mainly concentrated in more mineralized chloride lakes, and arsenic and uranium - in less saline, i.e. soda, as established. According to thermodynamic calculations, lithium is mainly present in lakes as Li⁺ ion; LiCO₃^- acts as second biggest in soda water bodies, and LiCl - in chloride. Uranium is mainly found as uranyl tricarbonate ([UO₂(CO₃)₃]^4-) and bicarbonate ([UO₂(CO₃)₂]^2-). Arsenic in oxidative environment of lakes is presented by hydroarsenate (HAsO₄^2-), and in reductive hydrosulphuric - dihydrogen arsenite (H₂AsO₃^-). Lithium does not form its own minerals in lakes. Reducing environment, in which it is precipitated as uranium hydroxide (U(OH)₄), may be a geochemical barrier for uranium. Sodium uranospinite (NaUO₂AsO₄) that may limit arsenic content in water too is likely to form under oxidative conditions. A single focus in the distribution of their contents in chloride lakes is observed for lithium and chlorine. Direct dependence of the concentrations of uranium and arsenic on the contents of hydrocarbonate and carbonate ions is typical of soda lakes. The lack of appropriate specialization in the catchment areas of most lakes with a wide variation of contents of lithium, uranium and arsenic in their water, and also the presence of direct dependencies on the contents of the main macrocomponents indicates the prevailing influence of geochemical environment in their accumulation, the formation of which is mainly determined by evaporative concentration of water and hydrolysis of aluminosilicate rocks. The prevalence of this or that process ensures the formation of a certain chemical type of lakes and the appropriate set of microelements.

The Ni/ZSM-5 samples were prepared by dry mechanical stirring of ZSM-5 zeolite with Ni nanopowder with 50 nm average particle size in terms of 0.5 mass %. Based on them, zeolite-containing catalysts with pseudoboehmite and hydrargillite containing 10, 20, 30 and 40 mass % of Al₂O₃ were obtained. Acid characteristics of the resulting samples were studied by the technique of temperature-programmed desorption of ammonia. The strength and concentration of catalyst acid sites were determined. Acidity decreased with increasing binder amount in zeolite, as established. Catalytic activity of nickel-containing samples with binder was studied during transformation of the straight-run gasoline fraction of oil. A part of pseudoboehmite used as binder to prepare catalysts could be replaced with its precursor, i.e . hydrargillite, as demonstrated. The yield of the liquid product, in the composition of which the aromatic hydrocarbon fraction decreased and the proportion of isoalkanes increased, rose during increasing binder content in the catalyst and carrying out transformation of the straight-run gasoline fraction of oil under high hydrogen pressure conditions.

Resistance of biocomposite fertilizers (BF) obtained via impregnation of porous substrates of bast and birch bark by an aqueous solution of K₂НРО₄ to washing-out of potassium was studied. The effect of drying temperature, acid treatment conditions, and initial potassium contents on its aqueous washing-out from the resulting fertilizers was found. Washing-out of potassium and phosphates from BF obtained under different conditions was compared. Fertilizers based on a substrate from the bast exceed those produced using birch bark by their resistance to washing-out of potassium by an average of 1.2 times, as demonstrated. Fertilizers production with maximum resistance to washing-out of potassium and phosphates requires that the amount of salt applied onto substrates should not exceed 29.5 mass %, as established. The resulting BF were characterized by the ability to slow isolation of the active components. After aqueous washing-out for 30 days, no less than 19.5 mass % of phosphates and potassium remained therein, which ensured the effect of prolonged action. The introduction of BF into peat soil in the amount of 5.0-15 mass % had little effect on its acidity. It was shown that BF based on substrates of bast and birch bark were not inferior to industrial granular fertilizer on their resistance to washing-out of phosphates, and on resistance to washing-out of potassium, on the contrary, surpassed it.

The paper presents the results of tar biochemical oxidation of Novokuybyshevsk Refinery with high contents of heteroelements in a model of the soil system. The microorganism population is restored to the initial level, and then increases in 20-30 times on the 4-5th day after pollution, as demonstrated. Enzyme activity of polluted soil increases in 1.5-1.8 times, which attests to an increase in oxygenase activity of microorganisms and consequently assimilation of different hydrocarbon compounds (HC). The formation and accumulation of incomplete HC oxidation products happens, as determined during biodegradation of tar components. The disposal of the studied oil product was 50 % of initial pollution on the 180th day of the experiment, as established. Native soil microflora is able to mineralization of almost all HC that are a part of the HC composition, as established by the GC/MS method. High molecular mass heteroatom tar components are also subjected to microbial degradation, as demonstrated. The structure of these species undergoes profound changes during degradation.