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Field-circuit models are very often used to model electromagnetic devices with conductive and non-linear magnetic materials. The numerical calculations of the field in the magnetic material must be combined with an equation of an external coil placed in the magnetic circuit. This means that the partial differential equations of the electromagnetic field in non-linear conductive materials and the non-linear ordinary differential equations must be solved together. Effective algorithms for solving such problems are still being developed. The article presents an algorithm directly providing the steady state solution without the simulation of transients. The basic assumption is that the solution can be predicted as a periodic time and space function, which is represented by appropriate Fourier series. The developed algorithm uses discrete partial differential operators for time and space derivatives. It allows us to create finite difference equations directly from the field and circuit equations, which take the form of algebraic equations, generally non-linear. This is a unique approach developed by us, which till now did not exist (and is not mentioned) in the literature. That algorithm is tested on a simple case of a solenoid coil with a ferromagnetic and conductive cylindrical core, in 2D space of radius and time. The calculation results confirm the effectiveness of the proposed approach both qualitatively, with regard to physical phenomena in ferromagnetic and conductive material, and quantitatively, in comparison with the results from specialized commercial software.

With the rising demand for mineral resources, efficient deposit management has become a critical challenge in modern mining. This article underscores the significance of geological modeling in coal deposit management, emphasizing the essential role that digital deposit models play across various mine departments. It outlines the methodology for creating geological models, detailing steps such as data digitization, validation, model construction, calibration, and continuous updates. The article examines three specific deposit modelling software programs (Minex, MineScape, and Carlson) highlighting their unique features and suitability for multi-seam coal deposits. The findings include the development of contour maps, structural and qualitative models, and conducting economic analyses. Additionally, the article discusses the importance of modelling tectonic disturbances and creating qualitative maps for effective deposit exploitation planning. It concludes by emphasizing that the integration of information technology with geological expertise is crucial for precise planning and optimization of mining operations, leading to more efficient and sustainable resource management.

We present the findings of a study based on a new inelastic electron-scattering experiment on the 12C nucleus focusing on the kinematic region of Q2=0.8GeV2/c2. The measured cross section is sensitive to the transverse response function and provides a stringent test of theoretical models, as well as of the theoretical assumptions made in Monte-Carlo event-generator codes developed for the interpretation of neutrino-nucleus experiments, such as DUNE and HyperK. We find that modern generators such as GENIE and GiBUU reproduce our new experimental data within 10%.

This paper describes an algorithm for finding steady states in AC machines for the cases of their two-periodic nature. The algorithm enables to specify the steady-state solution identified directly in time domain despite of the fact that two-periodic waveforms are not repeated in any finite time interval. The basis for such an algorithm is a discrete differential operator that specifies the temporary values of the derivative of the two-periodic function in the selected set of points on the basis of the values of that function in the same set of points. It allows to develop algebraic equations defining the steady state solution reached in a chosen point set for the nonlinear differential equations describing the AC machines when electrical and mechanical equations should be solved together. That set of those values allows determining the steady state solution at any time instant up to infinity. The algorithm described in this paper is competitive with respect to the one known in literature an approach based on the harmonic balance method operated in frequency domain.

The main aim of preventive conservation, ensuring protection of historic collections, is stabilization of relative humidity, and for some materials also temperature, in the interiors of historic buildings or museums. The improper microclimatic parameters may cause irreversible damages. On the other hand, strict control of indoor climate is expensive. Definition of optimal microclimate control in terms of energy use, taking into account most important, sometimes even contradictory factors, requires interdisciplinary cooperation, among others in the field of conservation, collections' care, architecture, building physics and HVAC systems. Due to the type of historic objects and specific microclimate requirements, hygrothermal simulations of whole historical buildings are essential for the most part of a case study. The paper presents an analysis of energy consumption according to various microclimate control scenarios for The National Museum in Kraków: The Gallery of 19th-Century Polish Art - located in Renaissance Cloth Hall in Kraków (UNESCO World Heritage Site). The analysis is based on the results of simulations performed with WUFI®PLUS software and in situ measurements. The microclimate control variants were developed, among others, on the basis of ASHRAE and ICOM-IIC guidelines. The research was supported by The Polish National Centre for Research and Development within \"HERIVERDE\" project.

The comprehensive use of available domestic energy resources, mainly coal and lignite, is the basis for the development of Poland’s economy and energy security due to the country’s large resource base. The implementation of clean coal technologies (CCT) is a necessary condition for maintaining coal’s leading position in Poland. Coal gasification technologies are seen as potentially attractive for the Polish economy, both for the chemical sector as well as for the mining sector. Working on the commercial implementation of coal gasification technologies, which ensures the effective substitution of scarce hydrocarbon fuels, will be a challenge to Polish industrial policy and support for CCT. This paper presents an analysis of coal gasification technologies using the decision support procedures, BOCR and SWOT analyses. These procedures helped determine the ranking of technologies and the types of development strategies plausible for the analysed technological variants. Taking into consideration the conditions of the Polish economy, the highest-ranking technologies included those aimed towards the production of methanol with the geological sequestration of carbon dioxide (CCS). In the case of underground coal gasification, it was found that the technology is not yet ready for implementation on a commercial scale and investment is subject to very high risk.

This paper presents the results of the preliminary experimental investigations of the disturbance of velocity field resulting from placing a vane anemometer in the analyzed air flow. Experiments were conducted in a wind tunnel with a closed loop. For the measurement process, Particle Image Velocimetry (PIV) method was used to visualize the flow structure and evaluate the instantaneous, two-dimensional velocity vector fields. Regions of inflow on the vane anemometer as well as flow behind it were examined. Ensemble averaged velocity distribution and root-mean-square (RMS) velocity fluctuations were determined. The results below are presented in the form of contour-velocity maps and profile plots. In order to investigate velocity fluctuations in the wake of vane anemometer with high temporal resolution hot-wire anemometry (HWA) technique was used. Frequency analysis by means of Fast Fourier Transform was carried out. The obtained results give evidence to a significant spatially and temporally complex flow disturbance in the vicinity of analyzed instrument.

This paper presents the improved methodology for the direct calculation of steady-state periodic solutions for electromagnetic devices, as described by nonlinear differential equations, in the time domain. A novel differential operator is developed for periodic functions and the iterative algorithm determining periodic steady-state solutions in a selected set of time instants is identified. Its application to steady-state analysis is verified by an elementary example. The modified algorithm reduces the complexity of steady-state analysis, particularly for electromagnetic devices described by high-dimensional nonlinear differential equations.

Energy based approach was used in the study to formulate a set of functions approximating the magnetic flux linkages versus independent currents. The simplest power series that approximates field co-energy and linked fluxes for a two winding core of an induction machine are described by a set of common unknown coefficients. The authors tested three algorithms for the coefficient estimation using Weighted Least-Squared Method for two different positions of the coils. The comparison of the approximation accuracy was accomplished in the specified area of the currents. All proposed algorithms of the coefficient estimation have been found to be effective. The algorithm based solely on the magnetic field co-energy values is significantly simpler than the method based on the magnetic flux linkages estimation concept. The algorithm based on the field co-energy and linked fluxes seems to be the most suitable for determining simultaneously the coefficients of power series approximating linked fluxes and field co-energy.

The aim of the investigations was the assessment of the size of harvest of five energetic basket willow clones at a plantation of the Forest Inspectorate Krzeszowice, the Forest Inspectorate Brodla branch, in the Malopolska voivodeship. The paper presents the effect of yielding of the willow Salix viminalis L., which is characterized by intense weight gain. An economic analysis was conducted for the plantation, the environmental effect was calculated and the social outcome was determined. An environmental impact analysis (EIA) showed, that the biomass combustion process emits far fewer pollutants than coal: 8 times less carbon oxide and 6 times less sulfur dioxide. The environmental effect is significant due to the reduction of pollutant emissions. The willow Salix viminalis L. is a plant, which easily adapts to vegetation on any soil. The plant growing does not require any special agrotechnical treatment. By the establishment and maintenance of willow plantations can contribute to rural development, increase income and reduce unemployment in the country. Farmers are willing to assume willow plantations, if you will guarantee the sale at attractive prices. Europe is looking for alternatives to conventional energy sources, combustion of which releases a greenhouse gas - carbon dioxide.