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2022 ◽  
Vol 130 (1) ◽  
pp. 160
Author(s):  
Л.А. Бобрева ◽  
Н.В. Сидоров ◽  
Н.А. Теплякова ◽  
М.Н. Палатников ◽  
С.А. Климин ◽  
...  

We have analyzed complex defects due to the presence of hydrogen bonds in the crystal structure in nominally pure lithium niobate crystals with different Li/Nb ratio, in crystals alloyed with magnesium and zinc in a wide concentration range (LiNbO3 : Mg (0.19-5.91 mol.% MgO) and LiNbO3 : Zn (0.04-6.5 mol. % ZnO)) and in the double-alloyed crystals (LiNbO3 : Y(0.24) : Mg(0.63 wt. %) and LiNbO3 : Gd (0.25) : Mg(0.75 wt. %)), obtained by technology of direct melt alloying, and also in the double-alloyed crystal (LiNbO3 : Mg(5. 05 mol.% MgO) : Fe(0.009 mol.% Fe2O3)) grown from a charge synthesized using the technology of homogeneous alloying with magnesium and iron Nb2O5. We revealed the influence of doping impurities on the concentration of OH-groups, the type and localization of complex defects in the crystal structure. The change in the number of hydrogen atom positions in the structure of the LiNbO3 crystal allow us to judge with sufficient accuracy whether the crystal composition is stoichiometric or congruent. For doped crystals of different compositions data were obtained testifying to changes in the character of complexation of OH-groups with point defects of the cationic sublattice with formation of defects: MеLi-OH-, MеLi-MеNb-OН. A change in the mechanism of entry of the dopant cation into the structure dramatically affects the change in the properties of the crystal.The difference in the frequencies (and, correspondingly, in the values of the quasi-elastic constants of the O-H bonds) in the spectrum of a congruent crystal and doped crystals can also be contributed by differences in the electronegativity and ionic radii of the principal and doping cations.


2021 ◽  
Vol 12 (1) ◽  
pp. 373
Author(s):  
Zlatin Zlatev ◽  
Mariya Georgieva-Nikolova ◽  
Hristo Lukanov

Mathematical models for describing the shape of eggs find application in various fields of practice. The article proposes a method and tools for a detailed study of the shape and peripheral contours of digital images of eggs that are suitable for grouping and sorting. A scheme has been adapted to determine the morphological characteristics of eggs, on the basis of which an algorithm has been created for obtaining their 3D models, based on data from color digital images. The deviation from the dimensions of the major and minor axes measured with a caliper and the proposed algorithm is 0.5–1.5 mm. A model of a correction factor has been established by which the three-dimensional shape of eggs can be determined with sufficient accuracy. The results obtained in this work improve the assumption that the use of algorithms to determine the shape of eggs strongly depends on those of the bird species studied. It is approved with data for Mallard eggs which have a more elliptical shape and correspondingly lower values of correction coefficient ‘c’ (c = 1.55–4.96). In sparrow (c = 9.55–11.19) and quail (c = 11.71–13.11) eggs, the form tends to be ovoid. After testing the obtained model for eggs from three bird species, sparrow, mallard, and quail, the coefficient of the determination of proposed model was R2 = 0.96. The standard error was SE = 0.08. All of the results show a p-value of the model less than α = 0.05. The proposed algorithm was applied to create 3D egg shapes that were not used in the previous calculations. The resulting error was up to 9%. This shows that in the test, the algorithm had an accuracy of 91%. An advantage of the algorithm proposed here is that the human operator does not need to select points in the image, as is the case with some of the algorithms developed by other authors. The proposed methods and tools for three-dimensional transformation of egg images would be applicable not only for the needs of poultry farming, but also in ornithological research when working with different shaped varieties of eggs. Experimental results show that the proposed algorithm has sufficient accuracy.


Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 67
Author(s):  
Masakazu Higuchi ◽  
Noriaki Sonota ◽  
Mitsuteru Nakamura ◽  
Kenji Miyazaki ◽  
Shuji Shinohara ◽  
...  

It is empirically known that mood changes affect facial expressions and voices. In this study, the authors have focused on the voice to develop a method for estimating depression in individuals from their voices. A short input voice is ideal for applying the proposed method to a wide range of applications. Therefore, we evaluated this method using multiple input utterances while assuming a unit utterance input. The experimental results revealed that depressive states could be estimated with sufficient accuracy using the smallest number of utterances when positive utterances were included in three to four input utterances.


Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8405
Author(s):  
Sean Cullen ◽  
Ruth Mackay ◽  
Amir Mohagheghi ◽  
Xinli Du

The fit of a lower limb prosthetic socket is critical for user comfort and the quality of life of lower limb amputees. Sockets are conventionally produced using hand-crafted patient-based casting techniques. Modern digital techniques offer a host of advantages to the process and ultimately lead to improving the lives of amputees. However, commercially available scanning equipment required is often expensive and proprietary. Smartphone photogrammetry could offer a low cost alternative, but there is no widely accepted imaging technique for prosthetic socket digitisation. Therefore, this paper aims to determine an optimal imaging technique for whole socket photogrammetry and evaluate the resultant scan measurement accuracy. A 3D printed transtibial socket was produced to create digital and physical twins, as reference models. The printed socket was photographed from 360 positions and simplified genetic algorithms were used to design a series of experiments, whereby a collection of photos were processed using Autodesk ReCap. The most fit technique was used to assess accuracy. The accuracy of the socket wall volume, surface area and height were 61.63%, 99.61% and 99.90%, respectively, when compared to the digital reference model. The scanned model had a wall thickness ranging from 2.075 mm at the top to 7.758 mm towards the base of the socket, compared to a consistent thickness of 2.025 mm in the control model. The technique selected did not show sufficient accuracy for clinical application due to the degradation of accuracy nearer to the base of the socket interior. However, using an internal wall thickness estimation, scans may be of sufficient accuracy for clinical use; assuming a uniform wall thickness.


2021 ◽  
Author(s):  
Anton Gryzlov ◽  
Liliya Mironova ◽  
Sergey Safonov ◽  
Muhammad Arsalan

Abstract Modern challenges in reservoir management have recently faced new opportunities in production control and optimization strategies. These strategies in turn rely on the availability of monitoring equipment, which is used to obtain production rates in real-time with sufficient accuracy. In particular, a multiphase flow meter is a device for measuring the individual rates of oil, gas and water from a well in real-time without separating fluid phases. Currently, there are several technologies available on the market but multiphase flow meters generally incapable to handle all ranges of operating conditions with satisfactory accuracy in addition to being expensive to maintain. Virtual Flow Metering (VFM) is a mathematical technique for the indirect estimation of oil, gas and water flowrates produced from a well. This method uses more readily available data from conventional sensors, such as downhole pressure and temperature gauges, and calculates the multiphase rates by combining physical multiphase models, various measurement data and an optimization algorithm. In this work, a brief overview of the virtual metering methods is presented, which is followed by the application of several advanced machine-learning techniques for a specific case of multiphase production monitoring in a highly dynamic wellbore. The predictive capabilities of different types of machine learning instruments are explored using a model simulated production data. Also, the effect of measurement noise on the quality of estimates is considered. The presented results demonstrate that the data-driven methods are very capable to predict multiphase flow rates with sufficient accuracy and can be considered as a back-up solution for a conventional multiphase meter.


Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1954
Author(s):  
Jaromír Moravec ◽  
Martin Švec ◽  
Šárka Bukovská ◽  
Jiří Sobotka

Temperature cycles generated during welding have a significant effect on the changes in the HAZ of welds, regardless of whether these are changes in structure or mechanical properties; however, it is problematic to obtain temperature cycles with sufficient accuracy across the entire HAZ so that they can be generally taken and used in welding simulations and for real experiments of processes occurring in HAZ. In particular, for a study in a specific location, it is important to know the maximum temperature of the cycle and the cooling rate defined mainly by the parameter t8/5. No studies in which anybody tries to find a mathematical description defining the basic parameters of temperature cycles in the HAZ could be found in the performed research. Therefore, the study presented in this paper results in a mathematical description defining the dependence of achieved maximum temperature on the distance from the fusion line in the HAZ of S460MC welds and with heat input values in the interval from 8 to 14 kJ·cm−1. Moreover, this paper presents the influence of heat input value on the weld pool geometry, including the effect of heat input value on grain coarsening in the highly heated HAZ.


2021 ◽  
pp. 153-157
Author(s):  
Н.Л. Великанов ◽  
О.В. Шарков

Лов рыбы с применением кошельковых неводов является наиболее распространенным в мире после тралового лова. Процессы кошелькования невода, выборки улова могут существенно влиять на остойчивость рыболовного судна (сейнера). В данной работе рассматривается влияние на угол крена силы, действующие со стороны орудия лова. Приведен алгоритм расчета, учитывающий координаты точки приложения силы натяжения троса, идущего к орудию лова, углы наклона троса, величину силы. Составлены расчетные зависимости для процессов крена, получены выражения для угла наклона корпуса судна. Приведены примеры расчетов. В частности, рассмотрено изменение угла крена от тягового усилия, высоты подъема канифас-блока для промыслового судна. Проведенные расчеты свидетельствуют о достаточной для инженерных расчетов точности и возможности использовать приведенный алгоритм при оценочных расчетах на различных стадиях проектирования. Важно учитывать возможность одновременного наложения ветровых нагрузок, действия волн на корпус судна. В этих случаях крен и дифферент будут возрастать. Поэтому спецификой промысловых судов является необходимость учета поведения судна при проведении промысловых операций. Fishing with the use of purse seines is the most common in the world after trawl fishing. The processes of pursing and seine sampling can significantly affect the stability of a fishing vessel (seiner). In this paper, the influence of forces acting from the fishing gear on the roll angle is considered. The calculation algorithm is given, taking into account the coordinates of the point of application of the tension force of the cable going to the fishing gear, the angles of inclination of the cable, the magnitude of the force. Calculated dependences for roll processes are compiled, expressions for the angle of inclination of the vessel's hull are obtained. Examples of calculations are given. In particular, the change in the roll angle from the traction force, the lifting height of the snatch–block for a fishing vessel is considered. The calculations carried out indicate sufficient accuracy for engineering calculations and the possibility of using the above algorithm for evaluation calculations at various stages of design. It is important to take into account the possibility of simultaneous imposition of wind loads, the action of waves on the hull of the vessel. In these cases, the roll and trim will increase. Therefore, the specifics of fishing vessels is the need to take into account the behavior of the vessel during fishing operations.


2021 ◽  
Vol 2131 (2) ◽  
pp. 022093
Author(s):  
T M Lindenbaum ◽  
O V Ignatieva

Abstract Traction currents and voltages in the overhead railroad contact line hypothetically obey the Gauss’s distribution law. An algorithm for statistical modeling of the Kolmogorov distribution for the unknown values of the Gaussian law parameters has been developed. For a large number of the modeling program implementations, it has been shown that testing the hypothesis about the distribution law without taking into account the number of unknown parameters leads to an unacceptable increase in the criterion significance and a decrease in its power. The distribution of the Kolmogorov criterion is calculated with sufficient accuracy for two unknown parameters, which allows its wide practical use.


2021 ◽  
Vol 72 (6) ◽  
pp. 419-422
Author(s):  
Karol Hilko ◽  
Vladimír Jančárik ◽  
Filip Kafka

Abstract The work is focused on the refinement of the determination of the magnetic field intensity in a Charpy-shaped steel sample. When measuring on an open sample, the intensity of the magnetic field cannot be determined directly from the current by the magnetizing winding. The distribution of the magnetic field around the sample was determined by numerical simulation, the dependence of its intensity on the distance from the sample surface is fitted with sufficient accuracy by a polynomial of the 3rd degree. A system of sensors sensing the distribution of the field at selected points above the sample was designed; by extrapolation using said fitting function, the intensity of the magnetic field on the surface of the examined sample is determined.


2021 ◽  
Vol 54 (6) ◽  
Author(s):  
Andreas Fischer ◽  
Sebastian Degener ◽  
Alexander Liehr ◽  
Thomas Niendorf

Surface treatments characterized by rapid heating and cooling (e.g. laser hardening) can induce very steep residual stress gradients in the direct vicinity of the area being treated. These gradients cannot be characterized with sufficient accuracy by means of the classical sin2Ψ approach applying angle-dispersive X-ray diffraction. This can be mainly attributed to limitations of the material removal method. In order to resolve residual stress gradients in these regions without affecting the residual stress equilibrium, another angle-dispersive approach, i.e. the universal plot method, can be used. A novel combination of the two approaches (sin2Ψ and universal plot) is introduced in the present work. Prevailing limits with respect to profiles as a function of depth can be overcome and, thus, high-resolution surface layer characterization is enabled. The data obtained are discussed comprehensively in comparison with results elaborated by energy-dispersive X-ray diffraction measurements.


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