Papers by Keyword: Spectral Analysis

Abstract: The dynamic nonlinear behavior of a beam, which is modeled as mass-spring mechanical systems, is the main subject of this investigation. Unlike most previous research that considers homogeneous and uniform beams, the findings of this research hold significant developments for the nonlinear vibration of non-homogeneous beams, which can be described as a bar-helical spring system. In this system, the mass of each bar changes over the length of the beam according to the local mass density of the non-homogeneous beam. The five-degree-of-freedom mass-spring model used in this paper can also be expanded to multi-degrees-of-freedom or even to a continuous system. The nonlinear beam response is investigated for three situations of increasing mass density and contrasted with its influence on dynamic features such as amplitudes, mode shapes, and natural frequencies. Therefore, three cases of mass distribution are considered for both symmetric and asymmetric nonlinear stiffness. Results are given as plots of vibration amplitude versus non-dimensional natural frequency for various cases of mass distribution. Obtained results underscore how mass density and stiffness symmetry critically influence the nonlinear beam dynamic response.

Abstract: According to the materials of the Rivne exploration expedition in Rivne region more than 15.3 million tons of phosphogypsum materials in rock dumps are stored. For further use and recycling of waste, it is necessary to evaluate the content of rare earth elements in phosphogypsum, which are of considerable economic value. The possible recycling of this production will increase the level of environmental safety through the use of more reliable engineering systems for the environmentally safe storage of phosphogypsum rock dumps. The migration of phosphorus, fluorine, sulfur, copper, chromium, manganese, zinc, lead, cadmium, iron, nickel and cobalt along the profile of the artificial ground cross-section was investigated experimentally. The results of studies confirmed the increased accumulation of metal in the phosphogypsum rock dumps. Analyzing the content of nickel, lead, sulfur, manganese, cobalt and zinc in experimental samples, we observe the distribution pattern, the content of which in samples is 2 – 3 times higher than the content of trace elements of the above-mentioned groundwater deposits. The results of the sorption and desorption of nickel, lead, sulfur, manganese, cobalt and zinc indicate that the rock is not an obstacle to the migration of trace elements and its aggregates in the rock and is observed only in the zone of full water saturation due to the filling of pore space. The conducted researches established the presence of phosphogypsum in man-made wastes of nickel, lead, cobalt, zinc, iron with a percentage content up to 1% per ton of rock waste.

Abstract: The article shows ways to improve spectral analysis of materials accuracy. It is proposed to perform image processing of a low-temperature plasma cloud during the analysis of the quantitative composition of materials. The experiment and addition of technical equipment of the spectrometer with a video surveillance system are described. An algorithm data processing is given that obtained during by testing of standard samples in various regimes in which the quantitative composition of various materials is determined This paper describes the addition of radiation control sensors to modern spectrometer. The given conditions and standard samples used to obtain the main results.

Abstract: Amber of amber-bearing deposits in Rivne-Volyn region of Ukraine has been analyzed. Relying upon instrumental techniques, physical and chemical as well as spectral analyses, and geological prospecting of the deposits, chemical composition and ultimate composition of amber occurring at the territory of Klesiv deposit (Ukraine, Rivne Region, Sarny District) have been identified. Klesiv amber contains the greatest part of inclusions; it contains 18 chemical elements. Basing upon the performed geological cross-section it has been determined that the amber occur in sandy soil and sandy-shale soil. The depth is insignificant – from 1 m to 10 – 15 m. Moreover, to determine the cost, experimental technique has been developed. The technique involves classification of the amber fragments according to their form, dimensions, and colour. Lithologic-and-facies sections of sites of Klesiv deposit have been obtained.

Abstract: The stress is made on the necessity to take into account the impact of higher while analysing the quality of voltage in power supply systems of coal mine. The process of resonances in power supply systems is explained in terms of physics, the sources generating this kind of interference are described. Mathematical dependences that allow to identify resonances in power supply systems are provided. The focus is placed on the feasibility of using spectral analysis in computations. To investigate the understudied aspects of voltage quality and electromagnetic compatibility and provide mathematical description for the analysis of resonances in electrical networks with powerful non-sinusoidal loads.

Abstract: Spectral analysis of different profiles obtained during straightness deviation measurement was performed. The several profiles are showed, for which the value of straightness deviation is the same, but its behavior differs greatly. Spectral parameters characterizing the type of straightness deviation are proposed. The automated system based on factors of fuzzy-set theory with implementation in the form of neural network is developed.

Abstract: Collaboration with professionals, particularly in the production of a key test of audio material, consider not only commonplace, but a necessary condition for objectification of input values of research whose content is aural component of the learning material. To get near the practice tests were filmed in three versions for voice, lower male voice, higher male voice and a female voice. Professional presenters under the leadership of literary director for us were the guarantee of a precise pronunciation of speech therapy without defects.

Abstract: The possibility of using lattice periodic functions in the processing of narrowband signals with methods of discrete Fourier transform, instantaneous spectral density, and synchronous detection providing reduction of the number of readouts being processed, is shown. Results of the method’s experimental evaluation are considered. Suggested method can be used for increasing efficiency of correlation analysis of narrow band signals and for precise measuring of mains electricity supply frequency.

Abstract: The article presents the data on development of methods for spectral analysis of human biological substrates in order to determine and restore its elemental balance. The developed method of mass concentration measurement of elements in human biological substrates (hair) by the method of arc atomic emission spectrometry using multichannel analyzer of emission spectra has been submitted for inclusion in the Federal register of RF techniques. By this technique we examined the concentration of macro- and microelements in the hair of 63 patients with ischemic stroke accompanied by depressive disorders (group 1) and post-stroke cognitive impairment (group 2) received in the order of emergency medical care in hospitals. There has been determined the increase of the upper limits of physiological norm of Co, Cd and Al in comparison with the reference values for both groups. In the second group of patients significantly higher content of Cr, Fe, Cd, Pb, Cu, Mn is observed. It is shown the necessity of introduction of new treatment protocols for stroke patients, including macro - and micronutrients to start pharmacological correction treatment as soon as possible.

Abstract: The paper deals with the resistive-acoustic monitoring method for early industrial spill detection on fuel and energy complex sites. The paper analyzes major indirect geophysical techniques used for oil plume detection. The scientific grounds for the application of the resistive-acoustic monitoring method are given. The paper considers the possibility of spotting medium non-uniformity by means of total resistance registration with the site non-uniformity localization due to seismic-acoustic effects. The relationship between soil electrical parameters and electric current frequency at varying soil moisture content is presented. Practical application of the resistive-acoustic method for oil-sludge spill monitoring on fuel and energy complex sites is described.