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The State Pharmacopoeia of the Russian Federation, 14th edition provides for determination of sub-visible particles (less than 100 µm in size) in parenteral dosage forms using the Coulter method, in addition to the light obscuration particle count test and microscopy. However, the proposed 100 µm aperture tube does not enable assessment of the whole range of sub-visible particle sizes. Therefore, research is needed to find optimal test conditions for determination of sub-visible particulate matter by the Coulter method. The aim of the study: modification of the Coulter-based procedure using a 200 µm aperture tube, and performance of validation studies. Materials and methods: Multisizer 4e Coulter counter, suspensions of reference latex particles (10 µm, 20 µm, and 43 µm), and a particulate count reference standard containing 0.998 × 106 particles/mL were used in the study. The following parameters were assessed during validation: accuracy, repeatability, linearity. Results: the study confirmed the feasibility of using the modified Coulter-based procedure with a 200 µm aperture tube. The following values were obtained during validation of the modified test procedure: accuracy was 5.3% (deviation from the mean value) as compared to the particulate count reference standard, and 4.2% as compared to the light obscuration method. Repeatability was 1% (relative standard deviation) for the particle concentration of approximately 10000 per 1 mL, and 7.6% for the particle concentration of approximately 300 per 1 mL. The study demonstrated the linearity of the procedure, the linear correlation coefficient was more than 0.99. Conclusions: the studied validation parameters of the modified test procedure were shown to comply with the acceptance criteria. The modified test procedure will enable assessment of the whole range of sub-visible particle sizes when testing parenteral solutions for particulate contamination: sub-visible particles.

Introduction. At present the most accurate estimate of ranges is specific to laser range finders using phase measuring techniques. Design of a pulsed laser range finder with short probe pulses enabling one to gain high resolution and accuracy of estimate of target range close to the phase range finders is the topical problem.Aim. Development of a receiving part of the pulsed laser rangefinder with precision characteristics; determination of the accuracy of the measurements; description of the hardware.Materials and methods. The construction of the receiving part of the precision pulsed laser rangefinder with a two-scale digital range estimation system implemented by counting clock generator pulses and an analog integrator that specifies the discrete range estimation was considered. Using the methods of mathematical statistics, the energy characteristics of the rangefinder were determined: the accuracy of the range estimation and the probability of false alarm were provided by the developed scheme. The hardware of the precision laser rangefinder was described.Results. The principles of implementation of the receiving part of the laser rangefinder with a two-scale digital system for estimating the distance to the object were given. The results of numerical simulation of rangefinder characteristics were obtained, confirming the accuracy of range estimation of the order of millimeters. In the implemented rangefinder scheme, the probability of false alarm was 10-4 during 200 s of observing signal and noise mixture. The hardware of the precision laser rangefinder with a digital two-scale range estimation was proposed.Conclusion. The implemented laser range finder approaches to the capabilities of phase laser rangefinders in terms of potential accuracy of distance up to millimeters, while implementing the specified parameter in rapidly changing phono-target environment. Using of short probing pulses with a duration of 10...20 ns allows one to achieve a resolution of up to 1.5 m. In contrast to the phase rangefinder the range can be estimated from a single probe pulse.

The aim of the work, the results of which are presented in the framework of the article, was to study the of electromagnetic radiation interaction laws in the frequency range 0.7…17 GHz with two-layer structures, the surface layer of which was made using powdered titanium dioxide, and the inner layer was made using a powder material based on oxide ferric iron. The thickness of the layers of the studied structures varied from 0.3 to 1 cm. To achieve this goal, theobjectives associated with the development of a methodology for the manufacture of multilayer structures based on composite materials containing transition metal oxides, as well as with the measurement of such structures samples electromagnetic radiation reflection and transmission coefficients in the frequency range 0.7...17 GHz. These measurements were carried out using a panoramic meter of reflection and transmission coefficients SNA 0.01–17. Based on the obtained measurement results, it was shown that in the frequency range 0.7…2 GHz, the lowest values of electromagnetic radiation reflection coefficient, reaching –20 dB, are characterized by structures whose surface layer thickness is 1 cm, and in the range 2 ... 17 GHz – structures, thickness the surface layer of which is 0.5 or 1 cm (depending on the thickness of the inner layer). The values of electromagnetic radiation transmission coefficient in the frequency range of 0.7...17 GHz of such structures reach –23 dB. Based on the results of the study, it is proposed to use the considered structures in the process of creating shielded rooms or improving the latter (for example, in cases, when it's necessary to reduce the level of passive interference in rooms shielded with metal materials).

Представлена имитационная модель энергоэффективной ячеистой сети дальнего радиуса действия на базе техно- логии передачи данных LoRa. Модель учитывает различные параметры узлов и каналов связи технологии LoRa. Серия компьютерных экспериментов позволила проанализировать время доставки и коэффициент доставленных пакетов. По результатам моделирования сделаны выводы о возможности использования ячеистой сети для приложений умных устойчивых городов ., The article presents a simulation model of energyefficient long-range mesh network based on LoRa technology. The model takes into account various parameters of nodes and communication channels of LoRa technology. A series of computer experiments allowed analyzing the delivery time and packet delivery ratio. Based on the simulation results, conclusions are drawn about the ability to use the mesh network for the application of Smart Sustainable Cities., №6.5 (2020)

The paper presents experimental findings on the influence of caramel color on the UV absorption spectra of tannin-containing liquids. The presence of caramel color in alcohol-containing brandy-type liquids is demonstrated to affect optical density at 280 nm, and therefore the results of spectrophotometric determination of tannins in brandies. A comprehensive approach incorporating a range of techniques, suсh as chemical testing for tannins, UV absorption spectroscopy, and quantitative permanganometric determination of tannins, is shown to be appropriate for the study of phenolic compounds.

The object of the study is acoustic metamaterial, which is a steel matrix with a periodic two-dimensional system of cylindrical cavities filled with hydrocarbon mixture. The induced resonances of fluid in cylindrical cavities of the periodic structure are studied for application in liquid fuel sensors. Theoretical studies of the structure show the possibility of exciting axisymmetric and spinning resonance modes in it in the frequency range with a high reflection coefficient of the structure, which manifest themselves as windows with a narrow bandwidth. Experimental studies confirm the existence of such resonances, and the asymmetric resonance mode is more evident. Measurements of various mixtures of gasoline and ethanol show that the sensor has significant sensitivity for distinguishing between conventional fuels, gasoline-based mixtures and the presence of additives in standard fuels.

Pulsed quartz-jacketed high-pressure xenon lamps, operating in the periodic pulse repetition modes, despite the appearing UV radiation sources of other types, remain a critical component of the processing equipment used in photochemistry, photo-medicine, nanoelectronics, biology, etc. Their main advantages, namely high power and radiation energy are slightly devalued by a relatively low efficiency of the shortwave radiation. Available literature data concerning the influence of various factors on the energy level of short-wave radiation in xenon need to be systematised and generalised because they have been obtained under conditions of uncontrolled quartz-jacketed transmission. The transmission of quartz can degrade after a while and, in addition, undergo great changes during the pulse. Besides, as a rule, in the literature, there is no detailed description of a complete kit of experimental setting. As a result, to analyse the factors affecting the efficiency of studying in the UV range is difficult, and there arises a relevant problem to optimise this type of discharge parameters to increase the efficiency in the range of 220-400 nm. A mathematical model of the radiation source, realistically describing the processes in the xenon plasma and in the stabilising envelope, can be a reliable ground for such a study. The paper shows an impact of the discharge channel diameter and length, the filling pressure of xenon, the pulse duration, the parameters of discharge circuit, and the current of pilot arc on the radiation yield. Based on the simulation-found relationship of internal plasma parameters (temperature distributions, fields of particle concentration and radiation, dynamics of electrical resistance of discharge channel, and plasma emission spectra) with radiation characteristics of discharge, are determined conditions to ensure the greatest radiation yield in the UV region. The experimental data prove the computational results. A material obtained gives practice-critical guidelines for development and correct selection of the short-wave radiation source.

Исследовали эффекты профилактического оптического излучения в синем диапазоне в течение четырех недель на функциональное состояние кардиореспираторной системы человека. При тестировании использовали нагрузочные пробы. Эффекты фототерапии проявились в отсутствии изменений ряда показателей сердечнососудистой системы, характерных для периода максимального прироста светового дня., Effects of preventive optical radiation in the blue range on the functional state of the human cardiorespiratory system were studied for four weeks using loading tests. The effects of phototherapy were evident as the absence of changes in several cardiovascular indexes characteristic for the period of maximum increase in daylight hours., №4 (2019)

Received: 14.11.2018. Accepted: 11.12.2018. Published: 31.12.2018. Studies of oxygen surface exchange kinetics for La0.6Sr0.4Co0.8Fe0.2O3–δ oxide were performed using the technique of isotopic exchange of molecular oxygen with analysis of gas phase isotopic composition in a static circulation system at the temperatures of 600–800 °С in the oxygen pressure range of 0.27–2.13 kPa. The values of interphase exchange rate and oxygen diffusion coefficient were determined. The effective activation energies for oxygen exchange and diffusion processes as well as the exponents in the dependence of these values versus oxygen pressure in the double logarithmic coordinates were calculated. The process of oxygen dissociative adsorption at the surface of La0.6Sr0.4Co0.8Fe0.2O3–δ oxide was found to be the rate-determining stage. This work is partly supported by the Russian Science Foundation (Project No. 17‑73‑10196) using facilities of shared access center “Composition of Compounds” of IHTE UB RAS.

The article presents a statistical mathematical model of a rarefied gas flow based on the method of particles in cells. This approach enables to define basic parameters of gas flow and vacuum systems in a wide range of pressures, including such an important parameter as conductivity of the vacuum system.Key assumptions in designing a mathematical model are: describing the collision of the molecules as hard spheres of elastic collision; considering the collisions to be paired and instant; the molecules velocity distribution corresponding to the Maxwell distribution. The essential feature is simulation of waiting time for the next collision. It depends on the state of the entire system of particles and is independent of what pair is involved in collision.The paper presents a detailed algorithm for implementation of a mathematical model to calculate conductivity. It includes three main stages. The first stage simulates only collisions of particles within the fixed cell of grid. The second stage simulates displacement of particles in accordance with their speed and time step, as well as interaction with the internal surfaces of the vacuum system. The final stage determines system conductivity.As an example, numerical experiments were conducted to determine conductivity of the long cylindrical channel in a wide range of pressures and conductivity of chevron screens too. Obtained data are compared with experimental data, and an error is evaluated. In molecular and transient conditions of gas flow the method of particles in cells gives high accuracy. In the viscous conditions the accuracy decreases because of originating region of continuous medium.This model can be used not only to determine conductivity of vacuum systems, but also to calculate gas flow parameters in systems with large flows (no restrictions for the flow rate value) for the channels and profiles with geometry of any complexity. An important feature is that it allows taking into account the sorption of gas on the channel surface and the temperature gradient in the system.Model based on the method of particles in cells can be used to calculate such systems as power generating channels of thermionic converter-reactors used in space vehicles, where it is necessary to know the parameters of a rarefied gas through a vapor flow of low-melting metal.

To improve the operational conductometric steam quality control at the TPP, CHPP, and NPP, the technique for NaCl and NH4OH concentration in the saturated and superheated steam of the high- and supercritical pressure steam generators is developed, and a device for its implementation is offered. The error of determination in the range of the concentrations specific for the operated power plants is estimated. The equations describing the behavior of the thermodynamic dissociation constant, and limiting equivalent conductance of NH4OH in a wide range of state parameters that can be used in calculating the concentrations according to the proposed technique, as well as in water chemistry organization and management, are proposed. The assessment of the approximation error of dependences for the experimental data on the dissociation constants and limiting equivalent conductance is given.