629 research outputs found
Comprehensive Processing of Fine Metallurgical Dust
The processing of fine metallurgical dust by pyrometallurgical methods leads to the accumulation of impurities and deterioration in the quality of blister copper. Fine dust contains copper, zinc, lead, arsenic and iron. A hydrometallurgical method for the separation of the main components into the following products is proposed: copper-zinc residue, iron-arsenic residue, lead residue. The hydrometallurgical scheme consists of three stages of leaching: neutral and using sulfuric and nitric acids. When processing metallurgical dust according to the proposed scheme, a solution containing copper, zinc, iron and arsenic is formed, as well as a lead containing precipitate. Arsenic and iron are removed from the solution in the form of iron (III) arsenate, after which zinc and copper are precipitated. Lead in sediment is in carbonated form. The developed technology allows the extraction of: 87% copper, 88% zinc, 83% iron, 83% arsenic, 99% lead in individual products.
Keywords: metallurgical dust, arsenic removal, nitric acid leachin
Path Loss Characterization for Intra-Vehicle Wearable Deployments at 60 GHz
In this work, we present the results of a wideband measurement campaign at 60
GHz conducted inside a Linkker electric city bus. Targeting prospective
millimeter-wave (mmWave) public transportation wearable scenarios, we mimic a
typical deployment of mobile high-end consumer devices in a dense environment.
Specifically, our intra-vehicle deployment includes one receiver and multiple
transmitters corresponding to a mmWave access point and passengers' wearable
and hand-held devices. While the receiver is located in the front part of the
bus, the transmitters repeat realistic locations of personal devices (i) at the
seat level (e.g., a hand-held device) and (ii) at a height 70 cm above the seat
(e.g., a wearable device: augmented reality glasses or a head-mounted display).
Based on the measured received power, we construct a logarithmic model for the
distance-dependent path loss. The parametrized models developed in the course
of this study have the potential to become an attractive ground for the link
budget estimation and interference footprint studies in crowded public
transportation scenarios.Comment: 4 pages, 8 figures, 1 table, accepted to EuCAP 201
ML-Assisted Beam Selection via Digital Twins for Time-Sensitive Industrial IoT
In this article, we propose a machine learning (ML)-assisted beam selection framework that leverages the availability of digital twins to reduce beam training overheads and thus facilitate the efficient operation of time-sensitive IoT applications in dynamic industrial environments. Our approach employs a digital twin of the environment to create an accurate map-based channel model and train a beam predictor that narrows the beam search space to a set of candidate configurations. To verify the proposed concept, we perform shooting-and-bouncing ray (SBR) modeling for a reconstructed 3D model of an industrial vehicle calibrated using the real-world millimeter-wave (mmWave) propagation data collected during a measurement campaign. We confirm that lightweight ML models are capable of predicting the optimal beam configuration while enjoying considerably smaller size compared to the map-based channel model.acceptedVersionPeer reviewe
ПОСТРОЕНИЕ МОДЕЛЕЙ ИЗМЕНЕНИЯ ВАЛЮТНОГО КУРСА НА ОСНОВЕ АНАЛИЗА ФУНДАМЕНТАЛЬНЫХ ПОКАЗАТЕЛЕЙ
The article deals with analysis of economic fundamental data and the issue of modeling of change in exchange rate EUR/USD. On the basis of statistical methods from the analysis was developed a model which helps to predict the range of currencies.В статье проводится анализ фундаментальных показателей экономики, исследуется вопрос моделирования изменения валютного курса EUR/USD. На основании статистических методов анализа разработаны модели, позволяющие прогнозировать движение курса на валютном рынке. Представлен анализ построенных моделей
Selection of parameters of optoelectronic systems for monitoring the wear for steam turbine rotor blading based on the value of the total error
Optoelectronic wear monitoring system of rotor blades of steam turbine low-pressure cylinders provide an assessment
of the chord value of the working blade in static conditions on a closed cylinder. However, these systems do not allow
the operator to assess the wear with the necessary error during shaft rotation. The control process is complicated by the
fact that the output edge of the blade is overlapped by the input edge of the next blade; therefore it is necessary to set a
scanning direction for each section that will ensure the formation of blade video frames, including both the input and
output edges. The shaft rotation mode requires the use of pulsed illumination of the edges of the working blades to reduce
the amount of image smudge; therefore it is necessary to select the focal length of the camera lens, the diameter of the
entrance pupil of the lens and the power of pulsed radiation sources. The development of a methodology for selecting
system parameters will help to reduce the complexity of designing systems for various turbine models and application
technologies. Therefore, this is an important task. A methodology has been developed for selecting the parameters of
the wear control systems of the working blades, which is based on the criterion of equality of the main components of
the total error of the chord value. The analytical studies used the relationship of the parameters of the matrix receiver of
optical radiation, illumination sources and the optical circuit with the required characteristics of the system. Computer
modeling of the information conversion process in the system under study took into account the relationship between
the parameters of the moving blades and the parameters of the optical circuit. The experimental estimation of the system
error in statics and dynamics is based on multiple measurements after calibration of the system according to known
parameters of the blades. When using the developed methodology, it is possible to achieve the required field of view and
a given error in controlling the chord value, due to the choice of: matrix optical radiation receiver, focal length of the
camera lens, diameter of the lens entrance pupil, and power of radiation sources. Using the example of the fifth stage of
the vane device of the K-1200 high unit power turbine, which is most susceptible to wear, it is shown that for maximum
values of the rotation angles of the video probe is 19° and the delay time of frame synchronization is up to 0.18 s, the
focal length of the camera lens should be less than 2.4 mm with a pulse illumination time of 0.05 s. Computer modeling
has shown that the marginal error of the system can reach 0.011 mm, which illustrates the possibility of reducing the
total error. Using the developed methodology, the main elements were selected and a layout of the system was created.
The requirements for exposure time and delay time of frame synchronization are formulated. The effectiveness of the
parameter selection methodology was confirmed by experimental studies of the system layout, which showed that
the estimate of the standard deviation of the random component of the chord control error in dynamics was 0.26 mm,
which is three times less than that of the previously developed system and meets the requirements for evaluating the
operability of the rotor blades of steam turbines during operation and repair. The proposed technique can be used by
developers of other optoelectronic means of contactless control of linear dimensions of parts oriented non-perpendicular
to the line of sight
Antimicrobial activity of nanostructured composites produced in Al/Zn nanoparticle oxidation in aqueous-alcoholic solutions
The paper studies the morphology, phase and elemental composition of bimetallic Al/Zn nanoparticles. It is found that metallic Al and Zn phases have interfaces within a single particle. The conversion mechanisms of Al/Zn nanoparticles in aqueous-alcoholic solutions with different water concentration are studied. It is shown that at 7 mass% water content aluminum oxidation and pseudoboehmite formation begin. Aluminum conversion increases with water content growth. At 20 mass% water content aluminum is oxidized completely, giving way to zinc oxidation. Microbiological studies show that samples containing AlOOH-Zn-ZnO phases exhibit the highest antimicrobial activity. Two-component metallic Al/Zn nanoparticles and composite particles in which initial components are completely oxidized to AlOOH-ZnO have the smallest inhibition zone
Potential technological solution for sampling the bottom sediments of the subglacial lake Vostok: relevance and formulation of investigation goals
The subglacial Lake Vostok in Antarctic is a unique natural phenomenon, its comprehensive study involves sampling of water and bottom surface rocks. For further study of the lake, it is necessary to drill a new access well and develop environmentally safe technologies for its exploration. This article discusses existing and potential technologies for sampling bottom surface rocks of subglacial lakes. All these technologies meet environmental safety requirements and are conducive for sampling. The authors have proposed an alternative technology, using a walking device, which, due to its mobility, enables selective sampling of rocks across a large area from a single access well. The principal issues, related to the implementation of the proposed technology, are investigated within this article. This report is prepared by a team of specialists with many years of experience in drilling at the Vostok Station in Antarctic and in experimental work on the design of equipment and non-standard means of mechanization for complicated mining, geological and climatic conditions
The use of immunoglobulins and monoclonal antibodies against COVID-19
Introduction. When a new disease occurs, one of the most affordable remedies is drugs containing specific antibodies to this infectious agent. The use of such drugs is aimed at reducing the amount of the pathogen in the macroorganism and the associated reduction in the severity of the symptoms of the disease or recovery.
The purpose of this review is to analyze the experience of using immunoglobulins and monoclonal antibodies in the treatment of COVID-19 patients during the pandemic.
Results and conclusion. The two main groups of medical protective agents that block the penetration of the SARS-CoV-2 virus into permissive cells are drugs obtained from blood plasma of convalescents (immunoglobulin) and human monoclonal antibodies. The first group of drugs in the treatment of COVID-19 includes blood plasma of convalescents, which can be successfully used for emergency prevention. The main disadvantage of using blood plasma convalescents is the difficulty of standardization due to the different content of specific antibodies in donors. Another disadvantage is the undesirable side effects in recipients that occur after plasma administration. An alternative approach to COVID-19 therapy is the use of humanized and genetically engineered human monoclonal antibodies against certain epitopes of the SARS-CoV-2 virus. For example, monoclonal antibodies against receptor-binding domain of the S-protein, which prevents the virus from entering permissive cells and interrupts the development of infection. The advantages of these drugs are their safety, high specific activity, and the possibility of standardization. However, the complexity of their production and high cost make them inaccessible for mass use in practical medicine
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