The use of fractional-order calculus for system modeling is a good alternative to well-known classic integer-order methods, primarily due to the precision with which the modeled object may be mapped. In this study, we created integer and fractional discrete models of a real object – a highspeed brushless micro-motor. The accuracy of the models was verified and compared.
In this paper, we randomly select 75 sets data of calcium sulfate hemihydrate (CSH) content and initial setting time, and the traditional test method of CSH and analyses initial setting time was used by complexometric titration. So the close relationship between them was studied in depth, which classification fitting data to be analyzed by regression analysis. The result shows that this regression analysis method can accurately determine CSH content in modified industrial by-product gypsum. The determination method has the advantages of simplification and rapid operation. As well as, the XRF quantitative analytical method was used to test the CSH content, which verified the accuracy of regression analysis method. The results also show that this method has high accuracy, and can simplify the traditional experimental process. The method developed is easier and more convenient and has broad prospects in application.
Basing on isolated vertebrae, fossil fishes of the order Gadiformes have been first discovered in sediments of the La Meseta Formation (upper Eocene — ?lower Oligocene) on Seymour (Marambio) Island, West Antarctica. This is one of the oldest and the only locality with the Gadiformes skeletal remains in the Southern Hemisphere. Other poorly preserved centra have been determined as Teleostei (order incertae sedis).
The article directly and indirectly refers to anthropological and philosophical texts which strive to discover and present the gender factor as important in the light of the humanities. The author refers to “Literackie nie-nazywanie. Onomastykon polskiej prozy współczesnej” (Literary Not-naming. Onomasticon of the modern Polish prose) by Magdalena Graf and indicates the femininity factor as a relevant one also in onomastics.
A simple analytical method is developed to estimate frequencies of longitudinal modes in closed hard-walled ducts with discontinuities in a cross-sectional area. The approach adopted is based on a general expression for the acoustic impedance for a plane wave motion in a duct and conditions of impedance continuity at duct discontinuities. Formulae for mode frequencies in a form of transcendental equations were found for one, two and three discontinuities in a duct cross-section. An accuracy of the method was checked by a comparison of analytic predictions with calculation data obtained by use of numerical implementation based on the forced oscillator method with a finite difference algorithm.
The motivation of this work was to define the reburning potential of sewage sludge gasification gas (syngas). Numerical simulation of co-combustion process of syngas in hard coal-fired boiler has been done. All the calculations were performed using the Chemkin program. Plug-Flow Reactor model was used. The calculations were modelled using GRI-Mech 2.11 mechanism. The highest NO conversions are obtained at the temperature of about 1000-1200 K. The highest reduction efficiency was achieved for the molar flow ratio of syngas equal to 15%. The combustion of hard coal with sewage sludge - derived syngas reduces NO emissions and the amount of coal needed to produce electricity and heat. Advanced reburning, which is a more complicated process gives efficiency of up to 80%. The calculations show that the analyzed syngas can yield better results.
The study analyses application possibilities of filtration and thickening models in evaluation of papermaking suspension drainage rate. The authors proposed their own method to estimate the drainage rate on the basis of an existing Ergun capillary model of liquid flow through a granular material. The proposed model was less sensitive to porosity changes than the Ergun model. An empirical verification proved robustness of the proposed approach. Taking into account discrepancies in the published data concerning how the drainage velocity of papermaking suspension is defined, this study examines which of the commonly applied models matches experimental results the best.
Samples of active coke, fresh and spent after cleaning flue gases from communal waste incinerators, were studied. The outer layers of both coke particles were separately removed by comminution mechanism in a spouted bed. Analyses included density, mercury porosimetry and adsorption. The remaining cores were examined to determine the degree of consumption of coke by adsorption of hazardous emissions (SO2, HCl, heavy metals) through its bed. The differences in contamination levels within the porous structure of the particles were estimated. The study demonstrated the effectiveness of active coke in the cleaning of flue gases.