AUTOMATION OF OPTIMAL IDENTIFICATION OF DYNAMIC ELEMENT TRANSFER FUNCTIONS IN COMPLEX TECHNICAL OBJECTS BASED ON ACCELERATION CURVES

Objectives. The aim of present paper is to minimise the errors in the approximation of experimentally obtained acceleration curves.Methods. Based on the features and disadvantages of the well-known Simoyu method for calculating transfer functions on the basis of acceleration curves, a modified version of the method is developed using the MathLab and MathCad software. This is based on minimising the sum of the squares of the experimental point deviations from the solution of the differential equation at the same points.Results. Methods for the implementation of parametric identification are analysed and the Simoyu method is chosen as the most effective. On the basis of the analysis of its advantages and disadvantages, a modified method is proposed that allows the structure and parameters of the transfer function to be identified according to the experimental acceleration curve, as well as the choice of optimal numerical values of those parameters obtained for minimising errors in the approximation of the experimentally obtained acceleration curves.Conclusion. The problem of optimal control over a complex technical facility was solved. On the basis of the modified Simoyu method, an algorithm for the automated selection of the optimal shape and calculation of transfer function parameters of dynamic elements of complex technical objects according to the acceleration curves in the impact channels was developed. This has allowed the calculation efficiency of the dynamic characteristics of control objects to be increased by minimising the approximation errors. The efficiency of the proposed calculation method is shown. Its simplicity makes it possible to apply to practical calculations, especially for use in the design of complex technical objects within the framework of the computer aided design system. The proposed method makes it possible to increase the accuracy of the approximation by at least 20%, which is an important advantage for its practical use

Нанесение защитных покрытий для повышения физико-механических свойств деталей из титанового сплава

На поверхню деталей зі сплаву ВТ-20 вакуум-плазмовим методом нанесено захисні покриття видів TiN, (TiC)N, (TiAl)N. Виявлено параметри процесу нанесення, що забезпечують отримання покриттів з найбільшою мікротвердістю.The work is dedicated to research structure and properties protective coatings of kinds TiN, Ti(CN), (TiAl)N marked on a surface of parts from alloy BT-20 by the vacuum – plasma method. The parameters of process of deposition are determined, which one provide obtaining coatings with the greatest microhardness.Работа посвящена изучению структуры и свойств покрытий видов TiN, Ti(CN), (TiAl)N, нанесенных вакуум-плазменным методом на поверхность деталей из сплава ВТ-20. Определены параметры процесса нанесения, которые обеспечивают получение покрытий с наибольшей микротвердостью

Defective proliferation and osteogenic potential with altered immunoregulatory phenotype of native bone marrow-multipotential stromal cells in atrophic fracture non-union

Bone marrow-Multipotential stromal cells (BM-MSCs) are increasingly used to treat complicated fracture healing e.g., non-union. Though, the quality of these autologous cells is not well characterized. We aimed to evaluate bone healing-related capacities of non-union BM-MSCs. Iliac crest-BM was aspirated from long-bone fracture patients with normal healing (U) or non-united (NU). Uncultured (native) CD271highCD45low cells or passage-zero cultured BM-MSCs were analyzed for gene expression levels, and functional assays were conducted using culture-expanded BM-MSCs. Blood samples were analyzed for serum cytokine levels. Uncultured NU-CD271highCD45low cells significantly expressed fewer transcripts of growth factor receptors, EGFR, FGFR1, and FGRF2 than U cells. Significant fewer transcripts of alkaline phosphatase (ALPL), osteocalcin (BGLAP), osteonectin (SPARC) and osteopontin (SPP1) were detected in NU-CD271highCD45low cells. Additionally, immunoregulation-related markers were differentially expressed between NU- and U-CD271highCD45low cells. Interestingly, passage-zero NU BM-MSCs showed low expression of immunosuppressive mediators. However, culture-expanded NU and U BM-MSCs exhibited comparable proliferation, osteogenesis, and immunosuppression. Serum cytokine levels were found similar for NU and U groups. Collectively, native NU-BM-MSCs seemed to have low proliferative and osteogenic capacities; therefore, enhancing their quality should be considered for regenerative therapies. Further research on distorted immunoregulatory molecules expression in BM-MSCs could potentially benefit the prediction of complicated fracture healing

Research of the vacuum thermocyclic nitrogen process in a plasma pulsing glow discharge

As a result of the studies, the regularities of the influence of vacuum thermocyclic nitriding in a pulsating glow discharge plasma  parameters on the microhardness, the diffusion saturation depth, the magnitude and distribution of residual stresses in the hardened layers of steel surfaces are established. Based on the use of expert assessment methods and the results of a series of screening experiments, optimization criteria (endurance limit and corrosion resistance) and controlled factors for mathematical modeling of the formation of strengthened ion-nitrated surface layers are determined. A mathematical model of the technology of the formation of reinforced surfaces of the vacuum thermocyclic nitriding in a pulsating glow discharge plasma  according to the criteria of endurance and corrosion resistance is obtained. An analysis of the studies showed that there are no general conclusions and recommendations on the selection of optimal technological parameters of the vacuum thermocyclic nitriding in a pulsating glow discharge plasma that would be used for the practical application of this technology. These circumstances confirm the need for further study of the vacuum thermocyclic nitriding in a plasma of a pulsating glow discharge of vacuum thermocyclic nitriding in a pulsating glow discharge plasma  technology and the feasibility of its optimization

Development and property investigation of composite catalysts made of mesh frame

Translated from Russian (Proceedings of Advanced Materials '99; Inst. of Materials Science Problems Nat. Academy of Sciences of Ukraine, Kiev, 1999)Available from British Library Document Supply Centre-DSC:9023.190(10057)T / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

The development of new wear-resistant coatings to increase operation characteristics of the details of mechanisms

Запропоновано комплексний підхід формування покриттів дискретної структури. Він базується на принципі забезпечення когезійної міцності покриття. Цей підхід дозволяє обирати параметри і розташування ділянок покриттів дискретної структури, що забезпечує зносостійкість деталей в реальних умовах експлуатації і підвищує їх надійність і довговічність.The complex method of approach for forming of discontinuous coatings is suggested. It is based on the principle of preventing adhesion cracking and allows choosing the size and deposition of the sections of discontinuous coatings. Such approach gives even wear on the sections with different Stress-strain State and allows increasing reliability and ensuring an original life of the details

Different Notch signaling in cells from calcified bicuspid and tricuspid aortic valves

Aims: Calcific aortic valve disease is the most common heart valve disease in the Western world. Bicuspid and tricuspid aortic valve calcifications are traditionally considered together although the dynamics of the disease progression is different between the two groups of patients. Notch signaling is critical for bicuspid valve development and NOTCH] mutations are associated with bicuspid valve and calcification. We hypothesized that Notch-dependent mechanisms of valve mineralization might be different in the two groups.Methods and results: We used aortic valve interstitial cells and valve endothelial cells from patients with calcific aortic stenosis with bicuspid or tricuspid aortic valve. Expression of Notch-related genes in valve interstitial cells by qPCR was different between bicuspid and tricuspid groups. Discriminant analysis of gene expression pattern in the interstitial cells revealed that the cells from calcified bicuspid valves formed a separate group from calcified tricuspid and control cells. Interstitial cells from bicuspid calcified valves demonstrated significantly higher sensitivity to stimuli at early stages of induced proosteogenic differentiation and were significantly more sensitive to the activation of proosteogenic OPN, ALP and POSTIN expression by Notch activation. Notch-activated endothelial-to-mesenchymal transition and the corresponding expression of HEY1 and SLUG were also more prominent in bicuspid valve derived endothelial cells compared to the cells from calcified tricuspid and healthy valves.Conclusion: Early signaling events including Notch-dependent mechanisms that are responsible for the initiation of aortic valve calcification are different between the patients with bicuspid and tricuspid aortic valves