An innovative method of fault detection in power transformers

The Bayesian classifier is a priori the optimal solution for minimizing the total error in problems of statistical pattern recognition. The article suggests using the classifier as a regular tool to increase the reliability of defect recognition in power oil-filled transformers based on the results of the analysis of gases dissolved in oil. The wide application of the Bayesian method for solving tasks of technical diagnostics of electrical equipment is limited by the problem of the multidimensional distribution of random parameters (features) and the nonlinearity of classification. The application of a generalized feature of a defect in the form of a nonlinear function of the transformer state parameters is proposed. This simultaneously reduces the dimension of the initial space of the controlled parameters and significantly improves the stochastic properties of the random distribution of the generalized feature. A special algorithm has been developed to perform statistical calculations and the procedure for recognizing the current technical condition of the transformer using the generated decision rule. The presented research results illustrate the possibility of the practical application of the developed method in the conditions of real operation of power transformers.

GEOGRAPHICAL PRINCIPLES OF DISTRIBUTION OF INVASIVE FLORA OF RAILWAYS IN KIROVOHRAD REGION

Development of transport capable to overcome distances of the planetary level, was caused to more intensive, than early, expansion allied, especially invasive, species of plants that become concurrent for aboriginal flora. Phytoinvasions are one of the most important geoecological problems of our time, as they disrupt the species composition and structure of natural phytocenoses, ultimately leading to the impoverishment of the plant component of landscapes and the reduction of biodiversity. One of leading factors in the spread of adventitious and, in particular, invasive species is rail transport, as a result of which seeds and organs of plants capable of taking root and gradually displacing the aboriginal flora get in the way. Although among the invasive flora of Kirovohrad region there are representatives of different systematic groups and life forms of plants, still clearly dominated by angiosperms and - at the same time - herbaceous plants. Main peculiarities of the space differentiation are described by the examples of railway stations of Holovanivsk and Znamianka situated consequently in the West and the East of the Kirovohrad region. The most common representative of the invasive flora of the railways of the studied region is ragweed, also widespread grindelia spread (in the west of the Kirovograd region) and sweet silique (in the east of the region). Of the families of flowering plants, the most widely represented are Aster (Compositae), a significant place is occupied by Cabbage (Cruciferous), Thin-legged (Cereals), Legumes and others. Factors contributing to the naturalization of invasive species and their rapid displacement of aboriginal flora are various. The main ones are eurybiont, unpretentious to the conditions of the habitat, the significant size of the aboveground phytomass. The internal diversity in the invasive flora of the region's railways is mainly due to the influence of the factor of the sectoral nature of natural conditions within the territory rather elongated from west to east. Therefore, in the presence of clear common features characterizing the invasive flora of the region, the differences associated with predominance of moisture-loving plants in the western part of the region and drought-resistant plants in the eastern part are noticeable. The practical use of the study results is associated with the possibility of improving the system of measures to combat phytoinvasions, taking into account the geographical features of the spatial distribution of individual species. Results of the investigation may be used during realizing tasks of ecologization of land using, especially defining priorities in the struggle with invasive species of the plants of railways. Discovered internal differentiation in expansion different allied species in Kirovohrad region gives a ground for defining the most important factors of distortion natural biodiversity in its different parts. Studying space peculiarities of expansion allied flora has a significance for create concrete actions directed to renewing initial space composition of phytocenosis and landscapes distorted by invasions. Key words: invasive flora, railway tracks, Kirovohrad region, adventitia, ragweed, grindelia spread, itching eastern.

Dynamic behaviours of the Double-end tuning fork based comb-driven microelectromechanical resonators for modulating the magnetic flux synchronously

MEMS resonators have been widely used in the magneto-resistive (MR) sensor for modulating the magnetic flux to enhance the detection limit. However, the manufacturing tolerances in MEMS fabrication processes make it challenging to fabricate the identical resonators with the same vibration frequency, which greatly decreases the detection limit of the MR sensor. To synchronize the MEMS resonators and improve the performance of the MR sensor, the double end tuning fork (DETF) based comb-driven MEMS resonators is proposed in this paper, making the system operate at the out-of-phase mode to complete the synchronization. The dynamic behaviour of the resonators is investigated through theoretical analysis, numerical solution based on MATLAB code and Simulink, and experimental verification. The results show that the transverse capacitances in the comb will significantly affect the resonance frequency due to the second-order electrostatic spring constant. It is the first time to observe the phenomenon that the resonant frequency increases with the increase of the bias, and it can also decrease with increasing the bias through adjusting the initial space between the fixed finger and the moving mass, they are different from the model about spring softening and spring hardening. Besides, the proposed DETF-based comb-driven resonators can suppress the in-phase and out-of-phase mode through adjusting the driving and sensing ports, and sensing method, meanwhile make the magnetic flux modulation fully synchronized, and maximize the modulation efficiency, and minimize the detection limit. These characteristics are appropriate for the MR sensor, even other devices that need to adjust the resonance frequency and vibration amplitude. Furthermore, the model and the design can also be extended to characteristic the single end tuning fork (SETF) based MEMS resonator and other MEMS-based MR sensors.

METHOD OF COMPREHENSIVE DATA ANALYSIS IN DIAGNOSTICS OF COMPLEX POWER EQUIPMENT

Предложен подход к диагностике сложного и габаритного оборудования на примере определения технического состояния дизельного двигателя. Отличительной особенностью дизельного двигателя является сложность конструкции, требующая применения комплекса методов для обеспечения полноты контроля и чувствительности при выявлении дефектов на ранних стадиях развития. Описана схема обработки данных, позволяющая повысить чувствительность при диагностике за счет комплексного анализа данных различной физической природы с использованием анализа сингулярного спектра. Повышение чувствительности обосновывается путем численного моделирования и обработки результатов измерения диагностических параметров в реальных производственных условиях. В качестве показателей чувствительности рассматриваются расстояния между координатами центров кластеров параметров исправного и неисправного состояния в исходном пространстве и в пространстве главных компонент. Продемонстрировано, что предлагаемый подход обеспечивает повышение чувствительности в условиях, когда влияние дефекта на диагностические параметры сопоставимо с действием случайных факторов в объекте диагностирования. Указанное повышение качества диагностирования достигается благодаря корреляции между параметрами за счет их представления в виде траекторных матриц. Помимо повышения чувствительности при выявлении дефектов также достигается и существенное сжатие информации, которая используется для определения состояния. Преимуществом предлагаемого подхода также является наглядная визуализация результатов The article suggests an approach to the diagnosis of complex and oversized equipment by the example of determining the technical condition of a diesel engine. A distinctive feature of the diesel engine is the complexity of the design, which requires the use of a set of methods to ensure complete control and sensitivity when detecting defects at early stages of development. We describe the data processing scheme, which allows you to increase the sensitivity in diagnostics due to the complex analysis of data of various physical nature using the principal component method. The increase in sensitivity is justified by numerical modeling and processing the results of measuring diagnostic parameters in real production conditions. Distances between coordinates of centers of clusters of parameters of serviceable and faulty state in initial space and in space of principal components are considered as indicators of sensitivity. We demonstrated that the proposed approach provides increased sensitivity in conditions where the effect of a defect on diagnostic parameters is comparable to measurement errors. The indicated improvement in the quality of diagnostics is achieved due to the correlation between the parameters due to their representation in the form of trajectory matrices. In addition to increasing sensitivity when detecting defects, significant compression of information that is used to determine the state is also achieved. The advantage of the proposed approach is also the vivid visualization of the results

On Fractional Geometry of Curves

Fractional Differential Geometry of curves is discussed, with the help of a new fractional derivative, the Λ-fractional derivative, with the corresponding Λ-fractional space. Λ-Fractional derivative completely conforms with the demands of Differential Topology, for the existence of a differential. Therefore Fractional Differential Geometry is established in that Λ-space. The results are pulled back to the initial space.

Classical and quantum speed limits

The new bound on quantum speed limit (in terms of relative purity) is derived by applying the original Mandelstam-Tamm one to the evolution in the space of Hilbert-Schmidt operators acting in the initial space of states. It is shown that it provides the quantum counterpart of the classical speed limit derived in Phys. Rev. Lett. 120 (2018), 070402 and the ℏ→0 limit of the former yields the latter. The existence of classical limit is related to the degree of mixing of the quantum state.

Regular attractors of asymptotically autonomous stochastic 3D Brinkman-Forchheimer equations with delays

<p style='text-indent:20px;'>We study asymptotically autonomous dynamics for non-autonom-ous stochastic 3D Brinkman-Forchheimer equations with general delays (containing variable delay and distributed delay). We first prove the existence of a pullback random attractor not only in the initial space but also in the regular space. We then prove that, under the topology of the regular space, the time-fibre of the pullback random attractor semi-converges to the random attractor of the autonomous stochastic equation as the time-parameter goes to minus infinity. The general delay force is assumed to be pointwise Lipschitz continuous only, which relaxes the uniform Lipschitz condition in the literature and includes more examples.</p>

Axial Symmetry Cosmological Constant Vacuum Solution of Field Equations with a Curvature Singularity, Closed Time-Like Curves, and Deviation of Geodesics

In this paper, we present a type D, nonvanishing cosmological constant, vacuum solution of Einstein’s field equations, extension of an axially symmetric, asymptotically flat vacuum metric with a curvature singularity. The space-time admits closed time-like curves (CTCs) that appear after a certain instant of time from an initial space-like hypersurface, indicating it represents a time-machine space-time. We wish to discuss the physical properties and show that this solution can be interpreted as gravitational waves of Coulomb-type propagate on anti-de Sitter space backgrounds. Our treatment focuses on the analysis of the equation of geodesic deviations.

RUANG HIJAU ALTERNATIF PADEMANGAN

Ray Oldenburg, in his book entitled "The Great Good Places" explains a concept of initial space, by which one can find comfort aside from the house (first place) and workplace (second place). Unfortunately, these days, this concept of place are not familiar within the community. Alternative Green Space of Pademangan is a place which accommodates the needs and interests of the community in daily life from where visitors can interact with others in a natural environment. Lacking in open space, various potential activities by the community, and the use of road as a public space are some of the reasons behind this project. Based on field study and regional analysis, this project seeks to become a third place that provides individually and communally. Regardless to it main focus on the surrounding community, this project also opens to public and allows visitors from outside the region, making it a comfortable place to socialized. Aiming to create a light and transparent building, and with the method of critical regionalism that responds to the region, this project attempts to create a spacious place and safe haven for visitors. Keywords: green; pademangan; third Place Ray Oldenburg, dalam bukunya yang berjudul “The Great Good Places” menawarkan sebuah konsep ruang ketiga, di mana seseorang dapat menemukan zona nyamannya di luar dari rumah (first place) dan tempat kerja (second place). Namun, sayangnya, saat ini third place belum menjadi bagian dari seluruh masyarakat, padahal third place memungkinkan seseorang untuk beristirahat sejenak dan bersosialisasi dengan sesama. Ruang Hijau Alternatif Pademangan merupakan sebuah wadah yang berusaha menjawab kebutuhan dan ketertarikan masyarakat dalam kehidupan sehari-hari di mana pengunjung tidak hanya dapat berinteraksi satu dengan yang lain tetapi juga dapat berinteraksi dengan ‘unsur hijau’. Kurangnya ruang terbuka hijau, banyaknya potensi kegiatan di dalam masyarakat, serta penggunaan ruang jalan sebagai ruang publik adalah beberapa alasan yang melatarbelakangi proyek ini. Berdasarkan hasil survey lapangan dan analisis kawasan, proyek ini berusaha untuk menjadi third place yang yang dapat dimanfaatkan baik secara individual maupun komunal. Terlepas dari fokus utamanya yang tertuju pada masyarakat sekitar, proyek ini juga terbuka untuk umum dan memungkinkan untuk pengunjung dari luar kawasan, menjadikannya sebuah tempat yang mampu menciptakan interaksi sekaligus memberikan kenyamanan bagi pengunjungnya. Dengan konsep bangunan yang ringan dan transparan, dan dengan metode critical regionalism yang berusaha menjawab kebutuhan kawasan, proyek ini berusaha untuk menjadi tempat yang dapat memberikan kesan lega dan menjadi tempat yang dapat diandalkan masyarakat setempat untuk beristirahat.

On the fractional deformation of a linearly elastic bar

Fractional derivatives have non-local character, although they are not mathematical derivatives, according to differential topology. New fractional derivatives satisfying the requirements of differential topology are proposed, that have non-local character. A new space, the Λ-space corresponding to the initial space is proposed, where the derivatives are local. Transferring the results to the initial space through Riemann-Liouville fractional derivatives, the non-local character of the analysis is shown up. Since fractional derivatives have been established, having the mathematical properties of the derivatives, the linearly elastic fractional deformation of an elastic bar is presented. The fractional axial stress along the distributed body force is discussed. Fractional analysis with horizon is also introduced and the deformation of an elastic bar is also presented.