Search

During the long-term operation of main run-of-river head powerhouses for hydroelectric power plants, technical changes that deteriorate the operational properties of their reinforced concrete structures can occur. Therefore, in order to substantiate the application of prestressed basalt composite reinforcements to strengthen reinforced concrete hydraulic structures in operation, a set of computational and experimental studies was carried out, taking into account their characteristic features. After 4 years of ageing, the serviceability and reliability of the beams with prestressed basalt composite reinforcements were demonstrated through stabilisation of the prestress losses and the values obtained for bearing capacity, deflection, and the width of the opening of the inter-bay construction joints and the deformations of the metal reinforcements and the basalt composite reinforcements. The bearing capacity of the investigated reinforced concrete beams reinforced with external transverse reinforcements was increased 1.4–2.5 times over that of the variants reinforced with longitudinal prestressed basal composite reinforcements. Furthermore, in this study, the impacts of static loads and seismic effects with a magnitude greater than 8 on the run-of-river hydroelectric power plant powerhouse were calculated based on dynamic design theory. Regarding applications to hydroelectric power plant structures and constructions, for which it is not always possible to determine the location of compressed or tensile zones during their operation nor under seismic action, our research results are suggestive of a reasonably positive effect. [ABSTRACT FROM AUTHOR]

Parallel–serial (hybrid) manipulators represent robotic systems composed of kinematic chains with parallel and serial structures. These manipulators combine the benefits of both parallel and serial mechanisms, such as increased stiffness, high positioning accuracy, and a large workspace. This study discusses the existing architectures and applications of parallel–serial robots and the methods of their design and analysis. The paper reviews around 500 articles and presents over 150 architectures of manipulators used in machining, medicine, and pick-and-place tasks, humanoids and legged systems, haptic devices, simulators, and other applications, covering both lower mobility and kinematically redundant robots. After that, the paper considers how researchers have developed and analyzed these manipulators. In particular, it examines methods of type synthesis, mobility, kinematic, and dynamic analysis, workspace and singularity determination, performance evaluation, optimal design, control, and calibration. The review concludes with a discussion of current trends in the field of parallel–serial manipulators and potential directions for future studies. [ABSTRACT FROM AUTHOR]

In Russia, a significant number of power facilities built in the 1960s and 1970s are located in regions where seismic effects were revised upward. This has led to an increase in the seismicity of the sites of facilities' locations by magnitude 1–2 (MSK-64) in comparison with the data of design documentation. During the long-term operating period of power facilities, the load-bearing capacity of building structures, as a rule, decreases. This article presents the results of computational and experimental studies of reinforced concrete structures of thermal power plants and hydroelectric power plants for seismic effects in the range of magnitude 4–10 (MSK-64). The computational studies were carried out using ANSYS 16.0 software, and experimental studies were carried out on stands modeling seismic impacts with the help of hydraulic cylinders. The results of the studies showed that cracking of reinforced concrete structures without strengthening occurs at magnitude 6.0 (MSK-64) of seismic impact, and destruction occurs at magnitude 7.5. Thus, the seismic resistance of structures without reinforcement does not meet the requirements for seismic resistance, and strengthening is required. This study considers a variant of strengthening based on external composite reinforcement with CFRP. It is shown that the strengthening of structures with composite material increases their earthquake resistance up to magnitude 9–10 (MSK-64). This article presents recommendations on the CFRP strengthening of building structures of power facilities, both after receiving damage under seismic impact and in a planned manner to increase seismic resistance. The novelty of this work lies in the fact that quantitative results of increasing the seismic resistance of structures depending on the placement and number of layers of composite material are given. [ABSTRACT FROM AUTHOR]

The report will address the main problem in risk measurement, namely the lack of a sufficiently long series of data for the various variables, so that the trend of their development can be formed with negligible error. A model will be made through a mathematical calculation in order to derive a long enough series with statistics reflecting the correlation between the individual variable indices and the standard deviation (volatility) to be able to obtain results with greater accuracy.

We live in a digital era. Nowadays almost all accounting and production project information are collected into long electronic spreadsheets that are easily accessible for the production managers so they can extract the data and analyze it according to their needs. In every work project, especially in long project production, IT or manufacturing, there is the need to perform an elaborated risk management, just because there is a gap of uncertainty from the process of planning to the final workflow cost. One main task that often causes problems is the quantitative risk analysis. In this article we will show how to use a well-known standard product, that is easily accessible even to micro entrepreneur – Microsoft Office/Excel. With the help of MS-Excel it will be cost effective and easy to extract the data and create standard risk simulations, which will help managers to take decisions and reduce their risk exposition.

This paper offers an overview of the verb system and person marking in a hitherto poorly described Sino-Tibetan language. We posit the existence of six verb classes based upon alternations of the final stem vowel, both for transitive and intransitive verbs. Person marking is described in comparison with that of closely related Rgyalrongic languages is found to be of interest for the reconstruction of the protosystem. The data analysed show that Rtau is also interesting from a typological point of view as it illustrates of a hitherto undescribed subtype of hierachical agreement.

Relevance. For more than 100 years, medical practice has used imaging methods to observe pathological changes localized in the human body. The first method was radiography, which became popular among doctors, but later it turned out that high radiation exposure increases the incidence of tumor diseases, which is why standards for permissible radiation doses were developed for patients and radiologists. The introduction of radiocontrast agents also had contraindications that should be taken into account. Ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), and angiography methods have significantly increased the diagnostic capabilities of instrumental methods. The purpose of this review is to analyze the advantages and disadvantages of modern imaging methods in medicine. Methods. To achieve the purpose of the review, a literature search was conducted in Google Scholar and PubMed databases. Results. 1) The main indication for the X-ray method is visualization of bone structures. 2) X-ray contrast methods are optimal for studying hollow organs and blood vessels. 3) The advantage of MRI is the ability to visualize soft tissue well. 4) CT helps to reconstruct the spatial architecture of organs. 5) Ultrasound allows you to observe the condition of the embryo and fetus, as well as internal organs. [ABSTRACT FROM AUTHOR]

The paper presents the results of studies of the linear and nonlinear dielectric properties of (R) -3-quinuclidinol embedded in porous aluminum oxide with a pore size of 300 nm, in comparison with the properties of bulk (R) -3-quinuclidinol. A decrease in the Curie temperature in the nanocomposite, both upon heating and cooling, in comparison with a bulk sample is revealed. A decrease in the phase transition temperature can be interpreted on the basis of known theoretical models for ferroelectric small particles.

The management of transport flows is based on transmitting, receiving and processing the information related to them by applying the principles of the system approach. In a theoretical-applied aspect, it manifests itself as an economic activity for the development and implementation of methods for collecting, storing, processing and distributing information for specific functions and operations in transport infrastructure systems. [ABSTRACT FROM AUTHOR]

The prerequisite for the study was a significant increase during a pandemic in the number of cyber crimes against property, caused by forced isolation, a reduction in the use of cash and an expansion of the scope of computer technology when concluding civil transactions. Purpose of the study: to identify trends in the criminalization of cyber crimes against property in foreign and Russian criminal law. To achieve the goal, the following methods were used: general scientific – analysis, synthesis, generalization, special scientific – statistical, formal logical, comparative legal, content analysis, the method of expert assessments. The results of the work were the classification of cyber crimes against property, the novelty is the definition of the most common type of these crimes – fraud, the identification of the growth of its individual forms during a pandemic. The issues related to the observed expansion of the scope of application of the liability for fraud, both in international law and in the national legislation of individual states, which are no longer limited to such traditional methods of committing it as deception and breach of trust. Cyber crimes in the Russian criminal legislation are investigated in their relation to crimes against property, recommendations are given for further optimization of the criminal legislation of the Russian Federation. In Russia, as in the rest of the world, during the period of the pandemic, an increase was recorded in crimes against property committed remotely, in relation to non-cash funds, using bank cards. When committing such acts, computer information, electronic data and programs are used as a method or means of committing them, which allows them to be classified as cyber crimes. Previously, cyber crimes were considered separately from traditional socially dangerous encroachments, but the massive use of information technology in the commission of certain types of crimes (in particular, crimes against property) requires a new approach to their description in national legislation.