The article discusses the features of the casting process of non-ferrous metals, the basic properties of various alloys, affecting the appearance of various defects of the resulting casting. The ...proposals to improve the efficiency of the casting of non-ferrous metals in metal molds and specific recommendations for improving the performance properties of metal depending on the melt being poured are given.
The results of approbation of new approach to monitoring soil salinization in irrigated massifs are presented. It is based on the indirect detection of soil salinization using long-term archive ...satellite data. The research was carried out by the example of irrigated lands in Maktaaral district, Turkestan oblast of the Republic of Kazakhstan. The frequency and terms of salt removal from soils were used as indicators of soil salinization level and were determined from the long-term (2016 to 2022) archive satellite data Sentinel-1,2 and Landsat-8. Information about the frequency of soil leaching from salts and the year of the last leaching allowed ranking fields by soil salinization degree. Comparison of the information obtained from the small-scale soil map with statistical data on field survey revealed a high similarity of soil salinization in the test region. The same approach may be used for other regions with irrigated soils subjected to secondary salinization. It does not require any additional adaptation and is based on simple algorithms of recognizing water surface by satellite data.
Features of the process of injection molding of non-ferrous metals and zinc alloys, in particular, consisting in the rate of crystallization of the process of melting, as well as cyclically ...repetitive temperature and shock loads of the forming surfaces of the mold, cause most defects, in which the form can be considered unfit for further use.
On the example of the test field located in the Tula region (Russia), the possibility of using remote sensing data for mapping the fertility of arable soils is considered. Analysis of ground-based ...spectrometry data showed that the correlation between the spectral reflectance of the surface of arable soils and fertility indicators increases with an increase in wavelength. The maximum value of the correlation coefficient for mobile phosphorus was 0.84, for humus content – -0.83, for mobile potassium – -0.7, for pH – -0.86, for exchangeable calcium – -0.88, for exchangeable magnesium – 0.67. When analysing the Sentinel-2 satellite data, the correlation coefficients turned out to be higher than in the case of ground-based spectrometry data. Band 5 of Sentinel-2 was found to be the most informative for the detection of most of the analysed parameters of soil fertility. Depending on the property, the R2cv of the models varied from 0.47 to 0.93. The best models were obtained for pH, humus, mobile phosphorus, and exchangeable calcium. Based on regression models, maps of fertility indicators of arable soils for the test field were produced. The obtained models can be used to organize operational monitoring of the main parameters of soil fertility in the field.
Modern polymeric materials have properties that, in some respects, exceed the properties of traditionally used materials (steel, aluminum and titanium alloys, wood). The uniqueness of the Rimamide ...polymer material is that it is possible to pre-design the material in such a way as to give the product from it the properties necessary for a particular application. The production of blanks and the use of Rimamide material for the manufacture of sliding and rolling bearings, bushings for wheels and rollers, pulleys, blocks, brackets, wheel hubs, gears, sprockets, gears and worm wheels and other parts to reduce weight, noise and vibrations. The characteristics of the material, examples of the manufacture of blanks, the advantages and disadvantages of the RIMAMID material for the manufacture of machine parts, prospects for use in mechanical engineering are shown. Due to their properties, they can be used in almost all industries. For example, modern aviation and space technology is characterized by the intensive use of new materials, technologies, and promising designs based on them. When using RIMAMID material using antifriction components (molybdenum sulfide, graphite, etc.), the friction coefficient is significantly reduced and the friction units can be operated without lubrication. The main advantages of this material is a low coefficient of friction for steel, which provides a 3-4-fold increase in the service life of parts in the friction units, as well as low weight, high strength, good machinability on metal cutting machines, resistance to aggressive environments, and environmental safety.
Joint plastic deformation of the components of bimetal 1 according to OST 3-6648-91 brass L90-steel 18JUA-brass L90 should be produced with the greatest possible compression to obtain the necessary ...strength of the joining of the layers, ensuring the strip looking into a roll without stratification. Preparation of contact surfaces before cold cladding is one of the most important technological operations. The influence of such factors on the strength of the bonding of bimetal layers as the surface hardening of contact surfaces, the microgeometry of contact surfaces, the temperature of diffusion annealing after cladding, the influence of the ratio of the thicknesses of bimetal layers was investigated. Technological recommendations for the production of bimetal 1 on OST 3-6648-91 brass L90-steel 18JUA-brass L90 by the method of cold cladding are developed.
The influenza NS1 protein is involved in suppression of the host immune response. Recently, there is growing evidence that prion-like protein aggregation plays an important role in cellular signaling ...and immune responses. In this work, we obtained a recombinant, influenza A NS1 protein and showed that it is able to form amyloid-like fibrils in vitro. Using proteolysis and subsequent mass spectrometry, we showed that regions resistant to protease hydrolysis highly differ between the native NS1 form (NS1-N) and fibrillar form (NS1-F); this indicates that significant structural changes occur during fibril formation. We also found a protein fragment that is capable of inducing the process of fibrillogenesis at 37 °C. The discovery of the ability of NS1 to form amyloid-like fibrils may be relevant to uncovering relationships between influenza A infection and modulation of the immune response.
•Recombinant NS1 protein is capable of forming amyloid-like fibrils.•Native form NS1 features a protease-resistant fragment from a.a. residues 1 to 78.•The fibrillar NS1 form's C-terminus is hydrolyzed by trypsin least of all.•During fibril formation, SDS-resistant non-native dimers form.•The NS1 Beta domain likely plays an important role in conformational transition.
Linear-quadratic (LQ) optimization is a fairly standard technique in the optimal control framework. LQ is very well researched, and there are many extensions for more sophisticated scenarios like ...nonlinear models. Conventionally, the quadratic objective function is taken as a prerequisite for calculating derivative-based solutions of optimal control problems. However, it is not clear whether this framework is as universal as it is considered to be. In particular, we address the question whether the objective function specification and the corresponding penalties applied are well suited in case of a large exogenous shock an economy can experience because of, e.g., the European debt crisis. While one can still efficiently minimize quadratic deviations around policy targets, the economy itself has to go through a period of turbulence with economic indicators, such as unemployment, inflation or public debt, changing considerably over time. We test four alternative designs of the objective function: a least median of squares based approach, absolute deviations, cubic and quartic objective functions. The analysis is performed based on a small-scale model of the Austrian economy and illustrates a certain trade-off between quickly finding an optimal solution using the LQ technique (reaching defined policy targets) and accounting for alternative objectives, such as limiting volatility in economic performance. As an implication, we argue in favor of the considerably more flexible optimization technique based on heuristic methods (such as Differential Evolution), which allows one to minimize various loss function specifications, but also takes additional constraints into account.
The search for an integral indicator of soil fertility is an important task, the resolving of which will allow for creating more accurate methods of soil monitoring and reduce time of field works and ...cost of soil samples analysis. It was proposed to use dielectric behavior (aspect) of soils as such an integral indicator. The solution to this problem lies in the application of a statistical method of spectral transformation of binary data of the amplitude of the reflected electromagnetic pulse along the entire depth of its duration (travel time) in the soil strata. The research was carried out using three soil types of arable and fallow land plots at VNIIMZ (Tver oblast) as an example. Of the attributes of spectral transformation, we used the parameter of spectral density of GPR signal and its distribution in the frequency domain, consisting of many close frequencies that make the greatest contribution to periodic pulse behavior in the subsurface of soils. GPR profiling was carried out during 2021 on a monthly basis. Variability of horizons and layers thickness was calculated through modules of amplitude maxima taking into account conductivity of the horizons (dielectric permittivity and signal velocity (transmission rate) in this medium). It was proposed to represent the dielectric behavior of soil in the form of abstract matryoshka models. The peculiarity of matryoshka lies in its internal structure based on similarity: each next inserted figure is similar to the external one in appearance (shape) and opening property (except for the last nondismountable one, which represents the frame of the dielectric soil image); the only difference is in size. The dielectric behavior of soil is distinguished by its core (quasi-invariant) part, as well as the dynamic part, changing through cycles of different duration. The creation of the model of soil behavior and its visual representation opens up new possibilities for the integrated assessment of soil status and real-time and low-cost monitoring of their fertility.
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