Wyniki wyszukiwania - BazTech

1

Evaluating material-extrusion additive manufacturing for hydrodynamic clutch rotor prototypes

Iwanicki Wojciech, Kotliński Jarosław, Osowski Karol, Olszak Artur, Musiałek Ireneusz, Musiałek Karol, Kęsy Zbigniew, Kęsy Andrzej

Advances in Science and Technology. Research Journal

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2026

|

Vol. 20, no. 5

239--253

EN

The article presents the results of numerical calculations examining the influence of channel roughness in a hydrodynamic clutch on the transmitted torque. Additionally, the study reports measurements of surface roughness and dimensional deviations of hydrodynamic clutch rotors. The rotors were manufactured using 3D printing based on material extrusion (MEX) technology and produced from three different materials: PLA, ABS, and PET-G. Based on the analysis of the obtained measurement and calculation results, the suitability of the MEX technology for manufacturing hydrodynamic clutch rotor prototypes is assessed. The results indicate that the surface roughness of the printed rotors is comparable to that of rotors produced by casting or machining. Moreover, the dimensional accuracy of the printed rotors lies within the tolerance range specified in the design of hydrodynamic clutch rotors. The article concludes with findings indicating that the adopted modeling and manufacturing procedure, employing the MEX technology, can be applied to produce hydrodynamic clutch rotor prototypes.

2

Zintegrowane modelowanie PMG Wierzchowice z wykorzystaniem GPU

Dudek Jacek, Wójcik Piotr, Preiss Marcin

Wiadomości Naftowe i Gazownicze

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2025

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R. 28, Nr 9 (319)

12-16

PL

W artykule przedstawiono proces budowy zintegrowanego modelu PMG Wierzchowice, obejmującego model statyczny, dynamiczny i produkcyjny. Metodyka uwzględniała zebranie danych, analizę rdzeni, logów i sejsmiki 3D, budowę modeli stratygraficznego, sedymentologicznego i facjalnego, z których powstał model statyczny przekształcony następnie w model dynamiczny w oprogramowaniu Petrel/Intersect. Model skalibrowano do 50 lat historii pracy obiektu, osiągając wysoką zgodność z danymi pomiarowymi. Kluczowym elementem było wykorzystanie środowiska obliczeniowego opartego na kartach graficznych (GPU), co skróciło czas symulacji z dni do minut. Zbudowano także model zintegrowany przy użyciu Intersect-Pipesim coupling, który pozwolił na pełne odwzorowanie interakcji złoża i infrastruktury. Wyniki potwierdziły możliwość zwiększenia pojemności czynnej i stabilnej pracy cyklicznej, a także wskazały na konieczność optymalizacji procesu tłoczenia w celu minimalizacji pogorszenia jakości gazu.

EN

The article presents the process of building an integrated model of the Wierzchowice Underground Gas Storage (UGS), comprising static, dynamic, and production models. The methodology included data acquisition, analysis of cores, well logs and 3D seismic, and the construction of stratigraphic, sedimentological, and facies models, which together formed a static model later transformed into a dynamic model using Petrel/Intersect software. The model was calibrated to 50 years of field and storage history, achieving high consistency with measurement data. A key element was the use of a computing environment based on Graphics Processing Units (GPU), which reduced simulation runtime from several days to minutes. An integrated model was also built using Intersect-Pipesim coupling, allowing full representation of the interactions between the reservoir and the surface network. The results confirmed the possibility of increasing the working gas capacity and maintaining stable cyclic operation, while also indicating the need to optimize injection and withdrawal processes to minimize gas quality deterioration caused by mixing.

3

Determining the optimal service area of a logistics center: a quantitative approach

Taran Ihor, Kairatkyzy Gulistan, Pavlenko Olexiy, Nefyodov Viktor, Muzylyov Dmitriy

Transport Problems

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2025

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T. 20, z. 3

5--18

EN

The efficiency of modern logistics is largely determined by the resilience of all components and links within the supply chain. Logistic centers play a critical role in ensuring this stability. The current study presents an approach to optimizing the service area of a logistics center for both urban and suburban regions. Key decisions for suppliers include selecting the mode of delivery – either direct or via a logistics center – and determining their optimal location. Based on expert surveys, delivery cost was identified as the primary decision-making criterion. A mathematical model was developed, incorporating such factors as the size of the service area, delivery density, cargo volume, vehicle capacity, and technical speed. Statistical analysis revealed strong nonlinear correlations between the parameters (r > 0.85). Newton’s method was employed for optimization. The analysis showed that the most significant factors affecting delivery cost are the service area, cargo volume, and vehicle capacity, while technical speed and delivery point density have less influence. The principal advantage of the proposed approach lies in the development of a simple and intuitive model that can enhance delivery strategies for logistics and transportation companies.

4

Global Stability of Different Fractional Orders Multi Input Multi Output Nonlinear Feedback Systems with Interval Matrices of Positive Linear Parts

Kaczorek Tadeusz, Sajewski Łukasz

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2025

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Vol. 19 No. 1

339--344

EN

The global stability of continuous-time fractional orders multi–input multi-output nonlinear feedback systems with interval matrices of positive linear parts is investigated. New sufficient conditions for the global stability of these class of positive nonlinear systems are established. A procedure for computation of gain matrix characterizing the class of nonlinear elements is given and illustrated on simple example.

5

Modelowanie matematyczne procesów nieliniowych oscylacyjnych w przewodzie długiej linii energetycznej

Chaban Andriy, Pukach Petro, Biletskyi Yuriy, Levoniuk Vitaliy, Erd Andrzej, Dydycz Aleksander, Arkanowicz Szymon

Przegląd Elektrotechniczny

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2025

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R. 101, nr 12

167--178

PL

W analizowanym modelu wykorzystano równanie cienkiej struny, która oscyluje w nieliniowym lepko-sprężystym środowisku izotropowym. Nieliniowość procesów oscylacyjnych jest powiązana ze składnikiem, który uwzględnia proces zewnętrznego rozproszenia energii opisywanego funkcją wykładniczą. Sformułowano matematyczne zadanie początkowobrzegowe (mieszane), dla którego udowodniono istnienie oraz jednoznaczność jego rozwiązania. Przedstawiono wyniki symulacji komputerowej procesów oscylacyjnych przewodu długiej linii energetyczne postaci przebiegów oscylacyjnych, przesunięcie węzła centralnego analizowanego przewodu.

EN

The analyzed model utilizes the equation of a thin string oscillating in a nonlinear, viscoelastic, isotropic environment. The nonlinearity of the oscillatory processes is related to a term that accounts for the external energy dissipation process described by an exponential function. A mathematical initial-boundary (mixed) problem is formulated, for which the existence and uniqueness of the solution are proven. Results of computer simulation of the oscillatory processes of a long power line conductor are presented.

6

Mathematical analysis of mechanical and thermal properties of hemp shivebased composites - regression model fitting

Hryniewicz Marek

Polish Technical Review

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2025

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No. 1

18--21

EN

This study investigates the dependencies between mechanical and thermal characteristics of hemp shive-based composite. The composites of this type are becoming popular because they are environmentally friendly, provide good thermal insulation, and have strong mechanical properties, serving as a viable alternative to traditional building materials. The research analyzes how these materials conduct heat and withstand pressure, using different ratios of hemp shive to binder. To predict the behavior of the mentioned materials, three mathematical models were applied: linear, quadratic, and exponential. The study has determined that linear models are the most effective for practical applications, as they have high R2 values, indicating a good fit with the data. A strong correlation was found between thermal conductivity and compressive strength, which helps in improving composite designs. The results endorse the use of hemp-based composites in construction, highlighting their ability to balance thermal efficiency, mechanical strength, and environmental sustainability. The study suggests more research to explore alternative binders, assess long-term durability, and evaluate the feasibility of large-scale production.

PL

W pracy zbadano zależności pomiędzy właściwościami mechanicznymi i termicznymi kompozytu na bazie paździerzy konopnych. Kompozyty tego typu cieszą się coraz większą popularnością, ponieważ są przyjazne dla środowiska, zapewniają dobrą izolację termiczną i posiadają dobre właściwości mechaniczne, stanowiąc realną alternatywę dla tradycyjnych materiałów budowlanych. W badaniu analizowano, w jaki sposób te materiały przewodzą ciepło i wytrzymują ciśnienie, stosując różne proporcje paździerzy konopnych do spoiwa. Do przewidywania zachowania tych materiałów zastosowano trzy modele matematyczne: liniowy, kwadratowy i wykładniczy. W badaniu ustalono, że modele liniowe są najskuteczniejsze w zastosowaniach praktycznych, ponieważ mają wysokie wartości R2, co wskazuje na dobre dopasowanie do danych. Stwierdzono silną korelację między przewodnością cieplną a wytrzymałością na ściskanie, co pomaga w ulepszaniu projektów kompozytów. Wyniki potwierdzają zastosowanie kompozytów na bazie konopi w budownictwie, podkreślając ich zdolność do równoważenia wydajności cieplnej, wytrzymałości mechanicznej i zrównoważenia środowiskowego. Badanie sugeruje dalsze badania w celu zbadania alternatywnych spoiw, oceny długoterminowej trwałości i oceny wykonalności produkcji na dużą skalę.

7

In-flight solar radiation intensity measurement using a small unmanned aerial vehicle

Ożóg Rafał, Jacewicz Mariusz, Głębocki Robert, Hanke Juliusz

Journal of Automation Mobile Robotics and Intelligent Systems

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2025

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Vol. 19, No. 4

52--59

EN

Recently, the Small Low-Altitude Long Endurance (LALE) solar-powered aircraft gained attention in the community. A reliable mathematical model of the aircraft and solar radiation should be available to design such a plane. This paper addresses the problem of measuring solar radiation in flight and validating its model. The configuration of the measurement system was described in detail. Moreover, the Multiplex Funcub NG was used as the intermediate research platform. The results of flight tests conducted in two different geographic locations in Poland confirmed that the proposed models enable precise prediction of the amount of harvested energy. The maximum solar radiation intensity measured in September at around noon was 829,3 W/m2 . Achieving perpetual flight functionality is possible in these conditions, provided that the aircraft has very low power consumption and a high wing aspect ratio. The obtained data can be used in the design process of the AZ-5 solar-powered plane.

8

Optimal control of electric energy quality,based on lexicographic approach

Voitiuk Yurii, Volotskyi Anatolii, Shullie Iuliia, Kovalchuk Maiia, Duisembayeva Laura

Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska

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2025

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T. 15, nr 3

22--28

EN

Important components of large and complex energysystems are electric energy supply systems, which perform the function of providing electric energy quality at the clamps of electric energy consumers. Developmentand realization of special methods and measures, enabling to synthesizethe corresponding technical facilities, which will provide the possibility toobtainthe basicindices of electric energy quality within the limits of DCTU (State standard of Ukraine) EN 50160:2014, is relevant technical problem. Taking into account the fact thatquality indices correspond todifferent operationmodes of electric energy supply systems consumers, the problem of searching methods, whichwould adequately represent the process of energy consumption, arises. In such operationconditions of modern systems of electric energy supplyit is expedient to use the methods of searching optimal solutions whichwould enable to influence simultaneously the improvement (or non-worsening) of the quality indices of electric energy.The given paper considers theoretical aspects of using one of the most suitablemethods for the solution of this problem, which relatesto multicriterial ones, when it is notpossible to express in simple terms the needto increase or decrease oneefficiency criterion (quality index) and it is necessaryto consider not one criterionbut a set of partial criteriawhich form vector criterion.Corresponding mathematical models for one of the widelyused problems of electric energy quality optimization have been formulatedand considered.Practical exampleof their application has been presented, it will give the possibility to simplifythecomputations and provideadequate realization of optimization processes.

PL

Ważnymi elementami dużych i złożonych systemów energetycznych są systemy zasilania energią elektryczną, które pełnią funkcję zapewniania jakości energii elektrycznej na zaciskach odbiorników energii elektrycznej. Opracowanie i wdrożenie specjalnych metod i środków umożliwiających syntezę odpowiednich urządzeń technicznych, które zapewnią możliwość uzyskania podstawowych wskaźników jakości energii elektrycznej w granicach DCTU (norma państwowa Ukrainy) EN 50160:2014, jest istotnym problemem technicznym. Biorąc pod uwagę fakt, że wskaźniki jakości odpowiadają różnym trybom pracy odbiorców systemów zasilania energią elektryczną, pojawia się problem poszukiwania metod, które odpowiednio odzwierciedlałyby proces zużycia energii. W takich warunkach eksploatacji nowoczesnych systemów zasilania energią elektryczną wskazane jest stosowanie metod poszukiwania optymalnych rozwiązań, które umożliwiłyby jednoczesny wpływ na poprawę (lub niepogorszenie) wskaźników jakości energii elektrycznej. W niniejszym artykule rozważono teoretyczne aspekty zastosowania jednej z najbardziej odpowiednich metod rozwiązania tego problemu, która odnosi się do metod wielokryterialnych, gdy nie jest możliwe wyrażenie w prosty sposób potrzeby zwiększenia lub zmniejszenia jednego kryterium efektywności (wskaźnika jakości) i konieczne jest uwzględnienie nie jednego kryterium, ale zestawu kryteriów cząstkowych, które tworzą kryterium wektorowe. Sformułowano i rozważono odpowiednie modele matematyczne dla jednego z powszechnie stosowanych problemów optymalizacji jakości energii elektrycznej. Przedstawiono praktyczny przykład ich zastosowania, który umożliwi uproszczenie obliczeń i zapewni odpowiednią realizację procesów optymalizacji.

9

Analysis of a variable geometry radial inflow turbine using 1D mean-line model

Samoilenko Dmytro

Engineering Transactions

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2025

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Vol. 73, iss. 3

463--483

EN

Despite great progress in 3D computational fluid dynamics (CFD), mathematical modeling used for turbomachinery analysis, the prediction of flow parameters in the rotor (impeller) of radial inflow turbines using existing turbulence models often yields unsatisfactory results. This is because real physical processes related to turbulence are very complex. Other limitations of CFD tools include numerical errors due to finite difference approximations. Thus, for the analysis and optimization of radial inflow turbines, empirical loss correlations applied to a mean-line 1D mathematical model can provide faster and more accurate results compared to CFD simulations. In this study, a 1D approach was used for the mathematical modeling of gas flow in a variable geometry radial inflow turbine with a vaneless volute distributor (VVD). The variable geometry turbine (VGT) was part of a turbocharging system. Combustion engine operation mode with high-power and low-crankshaft rotational speed was chosen, as engine performance under this condition is sensitive to turbocharger adjustment in terms of break specific fuel consumption (BSFC) and other critical parameters. An experimentally-based approach was used where gas flow characteristics in the VGT were calculated under real engine-turbocharger operating conditions. Accordingly, exhaust gas parameters were first measured on an experimental setup. Mathematical modeling then allowed to assess how adjustment in VGT influenced turbine indices, including loss distribution across the stage. It was also validated in this study that during high-load and low-crankshaft operating conditions of the compression ignition (CI) engine, it is recommended to minimize the cross-sectional area at the outlet of the volute acceleration section in the VGT. This adjustment results in better fuel efficiency and lower thermal loads on turbine components, despite a slight reduction in the turbine’s overall efficiency.

10

Temperature field in a finite cylindrical channel with biomass transferred due to the rotation of a heated helix

Piddubniak Olexa, Ledakowicz Stanisław

Chemical and Process Engineering : New Frontiers

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2025

|

Vol. 46, nr 4

art. no. e113

EN

The temperature distribution field in a cylindrical channel of finite length, which was filled with moving biomass due to the rotation of an induction-heated helix, was analyzed. The outer and inner surfaces of the channel were assumed to be thermally insulated and to meet third-kind boundary conditions on temperature at the entrance and exit of the reactor. To solve the thermal conductivity problem, the desired function was decomposed into a Fourier–Bessel series with respect to the angular and radial variables. Then, an integral Laplace transformation was applied with respect to time. The exact solution was replaced by an approximate solution for practical numerical reasons. A detailed numerical analysis of the temperature field was performed. The analysis showed that the duration of the transition process was inversely proportional to the square of the biomass movement velocity and that temperature oscillation amplitudes in the quasi-stationary regime were weak. However, these oscillations are clearly manifested under space-time resonance conditions, especially when the velocities of helix rotation and rectilinear movement of the biomass are correspondingly selected. It was also determined that a local temperature increase occurs at low velocities of mass movement.

11

Characterization of the Gu-Ge-In: Microstructural, Mechanical, Electrical Properties, Scheil and Lever Simulation

Djordjević Aleksandar, Zečević Milena, Minić Dusco, Kolarević Milan, Balanovic Ljubiša, Manasijevic Dragan, Petrović Milenko

Archives of Metallurgy and Materials

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2025

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Vol. 70, iss. 1

299--309

EN

Based on application of Cu-based alloys and special application of Ge-based alloys it is from huge interest to study properties of the Cu-Ge-X alloys. In this paper selected system is Cu-Ge-In. This system was previously studied by our group. In this paper results are focused on electrical and mechanical properties. Experimental tests were performed on 12 ternary alloys. Six different experimental techniques were used to test the ternary alloys. The microstructure was tested using light optical microscopy (LOM) and scanning electron microscopy (SEM). The composition of the phases and the composition of the alloys were examined by energy dispersive spectroscopy (EDS). X-ray diffractometric analysis (XRD) was used to determine the phases. Properties such as hardness and electrical conductivity tests were performed. Those properties were used for calculation and modeling those properties along all composition ranges. Isothermal section at 25°C were predicted. Calculated isothermal section and were compared with results of the EDS and XRD test. Good agreement of calculated and experimental result has been reached. Best results of electrical conductivity and hardness give alloys with composition Cu80.93Ge9.86In9.21.

12

Modelowanie przekształtnikowych napędów wielomaszynowych

Beniak Ryszard

Śląskie Wiadomości Elektryczne

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2024

|

Nr 1 (151)

4-10

PL

Artykuł omawia możliwość modelowania matematycznego systemu wielonapędowego z wykorzystaniem algorytmów zmiennostrukturalnych. Przedstawione są podstawowe: właściwości, trudności i ograniczenia tego typu algorytmów. Dokładniej omówiony jest najtrudniejszy etap stosowania tego typu algorytmów, czyli obliczania napięć na gałęziach nie opisanych w danej chwili przez rozwiązywane numerycznie równania różniczkowe. W drugiej części artykułu przedstawiona jest implementacja algorytmu w programie modelującym platformę Stewarta będącą systemem zawierającym działające zgodnie trzy napędy przekształtnikowe. Uzyskane rezultaty potwierdzają efektywność modelowania tego typu systemów.

EN

The article discusses the possibility of mathematical modeling of a multi-drive system using variable-structure algorithms. The basic properties, difficulties and limitations of this type of algorithms are presented. The most difficult stage of using this type of algorithms is discussed in more detail, i.e. calculating voltages on branches not currently described by numerically solved differential equations. The second part of the article presents the implementation of the algorithm in a program modeling the Stewart platform, which is a system containing three converter drives operating accordingly. The obtained results confirm the effectiveness of modeling this type of systems.

13

Stabilization of poloxamine and poloxamer block copolymer complexes in chlorinated organic solvents – mathematical modelling

AlHanbali Othman A., Al-Shukri Salah Mahdi, Dardas Abdel Khaleq Y., Jaradat Nidal A., Shraim Naser Y., Arafat Mosab

Polimery

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2024

|

Vol. 69, nr 9

475--483

EN

To develop a mathematical model describing the behavior of chromophore complexes, the main factors influencing the stability of poloxamine and poloxamer complexes were determined. Gel permeation chromatography, ultraviolet absorbance measurements and FT-IR were used for the analysis. It was found that the studied complexes in chlorinated organic solvents are unstable in the presence of oxygen, air, or water. The developed mathematical model allows for more effective planning and execution of experiments due to the possibility of predicting UV absorption based on the distribution of complexes in chlorinated solvents.

PL

W celu opracowania modelu matematycznego opisującego zachowanie kompleksów chromoforowych określono główne czynniki wpływające na stabilność kompleksów poloksamin i poloksamerowych. Do analizy zastosowano chromatografię żelową, pomiary absorbancji w ultrafiolecie i metodę FT-IR. Stwierdzono, że badane kompleksy w chlorowanych rozpuszczalnikach organicznych są niestabilne w obecności tlenu, powietrza lub wody. Opracowany model matematyczny pozwala na efektywniejsze planowanie i wykonywanie eksperymentów ze względu na możliwość przewidywania absorpcji UV na podstawie rozkładu kompleksów w chlorowanych rozpuszczalnikach.

14

A quantitative study between HPGR and cone crusher aided ball mill grinding : mathematical modeling by evaluating the possible microfracture effect produced by HPGR technology and cone crusher

Rodríguez-Torres I., Tuzcu E.T., Reyes Iván A., Rosales-Marín G.

Physicochemical Problems of Mineral Processing

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2024

|

Vol. 60, iss. 1

art. no. 177620

EN

High Pressure Grinding Rolls (HPGR) have been used in the mining industry for decades. However, there are limited quantifications of the particle properties after comminution. Furthermore, the influence of microcracks in grinding provided by this technology has not been extensively quantified. In the recent work, there were two comminution paths tested: 1 (Jaw crusher + cone crusher + ball mill) and 2 (Jaw crusher + HPGR + ball mill). The possible weakening effect aiding ball mill grinding due to microcracks of HPGR path was shown via specific energy, fines generation and breakage rate measurements. To achieve a quantification about the impact of microcracks and the high rate of reduction rate of HPGR technology, first the product was reconstructed using Rosin Rammler's Weibull double formula and the similar particle size distribution was obtained by a conventional cone crusher. By this way the feed size distribution to the grinding stage remained constant regardless of the type of crushing process (HPGR or cone crusher). The results showed that the microfractures generated by the HPGR technology influence the specific energy consumption, fines generation and breakage rates. Ball mill after HPGR consumed 12.46 kWh/t of specific energy, however ball mill after cone crusher consumed 14.36 kWh/t of specific energy. The experimental methodology proposed in this paper maintains a consistent feed size range (-1500 to +41.31 μm) to show that the size reduction observed in the sample undergoing HPGR grinding is not the primary factor contributing to reduced energy consumption and increased fines generation. Instead, it is predominantly associated with the microfractures generated through the compression in HPGR technology; the energy reduction (optimization) of a grinding path is shown in the study.

15

Influence of the building’s thermal insulation on intermittent heating mode efficiency

Balasanian Hennadii, Klymchuk Oleksandr, Luzhanska Ganna, Aksyonova Inna, Voronenko Serhii

Management Systems in Production Engineering

|

2024

|

nr 4 (32)

484--488

EN

The results of mathematical modeling of a building’s thermal insulation influence on the efficiency of intermittent heating mode are presented. This work aim is to assess the influence of thermal insulation on the efficiency of using the intermittent heating mode for the educational building of the Odessa National Polytechnic University’s Heat Engineering Laboratory. The paper analyzes the factors related to improving the efficiency of the programmed heat supply mode. Modeling of the operating modes for heat supply system operated in intermittent heating mode is carried out. There was performed the mathematical modeling of the heating system operation modes for the most unfavorable climatic conditions at low outdoor temperatures, with respective system efficiency indicators obtaining. The potential of energy saving level for administrative, educational, and office buildings depending on the thickness of thermal insulation of external and internal walls is studied. Recommendations have been elaborated for the use of buildings thermal insulation to improve the efficiency of intermittent heating.

16

Approximate and analytic flow models for leak detection and identification

Tatara Marek S., Kowalczuk Zdzisław

International Journal of Applied Mathematics and Computer Science

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2024

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Vol. 34, no. 3

391--407

EN

The article presents a comprehensive quantitative comparison of four analytical models that, in different ways, describe the flow process in transmission pipelines necessary in the task of detecting and isolating leaks. First, the analyzed models are briefly presented. Then, a novel model comparison framework is introduced along with a methodology for generating data and assessing diagnostic effectiveness. The study presents basic assumptions, experimental conditions and scenarios considered. Finally, the quality of the model-based diagnostic estimators is assessed, focusing on their bias, standard deviation, and computational complexity. Here, several optimality criteria are used as detailed indicators of the quality and performance of the estimators in a multi-criteria Pareto optimality assessment.

17

Hard coal supplies and selected environmental regulations: A Case Study of the Polish Power Sector

Malec Marcin

Gospodarka Surowcami Mineralnymi

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2024

|

T. 40, z. 1

125--150

EN

The volatility of raw material prices and the rising prices of CO2 emission allowances when using fossil fuels to produce electricity and heat are still relevant problems for owners of generating units. The decision-making tools are used in the fuel purchase process. However, these tools should also consider environmental issues. The article’s main objective is a quantitative analysis of the potential for reducing costs associated with supplying and using hard coal in public power plants as a result of considering the costs of environmental protection and CO2 emission allowances in the process of planning this fuel supply. A mathematical model was developed to optimize the supply of hard coal for the power industry. The tool and elaborated research scenarios made it possible to calculate and analyze the impact of considering the costs of emissions of harmful substances into the environment and CO2 emission allowances on the planning of coal supplies and the reduction of costs related to acquiring and using coal by public power plants. The calculation results were presented on the example of the Polish power sector. The model’s results confirm that the appropriate selection of coals, taking into account the quality parameters determining the amount of emissions of harmful substances, reduces the amount of these emissions and the total costs of acquiring and using coal in electricity production. However, depending on the considered scenario, the scale of this impact varies. The results of the optimization of coal supplies to power plants and their proper interpretation may constitute an important contribution to making management decisions in energy companies.

PL

Problem zmienności cen surowców, wzrastających cen uprawnień do emisji CO2 oraz zaostrzanych limitów emisji przy wykorzystywaniu paliw kopalnych do produkcji energii elektrycznej i ciepła jest wciąż aktualny dla właścicieli jednostek wytwórczych. Budowane narzędzia wspomagające proces podejmowania decyzji przy doborze surowców do procesu spalania powinny jednak uwzględniać również kwestie środowiskowe. Głównym celem artykułu jest ilościowa analiza potencjału redukcji kosztów związanych z pozyskaniem i wykorzystaniem węgla kamiennego w elektrowniach zawodowych, w rezultacie uwzględnienia w procesie planowania dostaw tego paliwa, kosztów ochrony środowiska oraz uprawnień do emisji CO2. Opracowano model matematyczny do optymalizacji pozyskiwania węgla kamiennego przez energetykę zawodową. Zbudowane narzędzie oraz opracowane scenariusze badawcze umożliwiły przeprowadzenie obliczeń i wykonanie analizy wpływu uwzględnienia kosztów ochrony środowiska oraz uprawnień do emisji CO2 w procesie planowania dostaw węgla, na redukcję kosztów związanych z pozyskaniem i zużyciem węgla w elektrowniach zawodowych. Wyniki modelu potwierdzają, że odpowiedni dobór węgli wpływa na redukcję całkowitych kosztów pozyskania i wykorzystania węgla w procesie produkcji energii elektrycznej. Wyniki optymalizacji dostaw węgla do jednostek wytwórczych i ich właściwa interpretacja mogą stanowić istotny wkład w podejmowaniu decyzji zarządczych w przedsiębiorstwach energetycznych.

18

Artificial Neural Network-aided Mathematical Model for Predicting Soil Stress-strain Hysteresis Loop Evolution

Bocheńska Marta, Srokosz Piotr

Civil and Environmental Engineering Reports

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2024

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Vol. 34, no. 3

120--135

EN

This study presents a novel approach to forecasting the evolution of hysteresis stress-strain response of different types of soils under repeated loading-unloading cycles. The forecasting is made solely from the knowledge of soil properties and loading parameters. Our approach combines mathematical modeling, regression analysis, and Deep Neural Networks (DNNs) to overcome the limitations of traditional DNN training. As a novelty, we propose a hysteresis loop evolution equation and design a family of DNNs to determine the parameters of this equation. Knowing the nature of the phenomenon, we can impose certain solution types and narrow the range of values, enabling the use of a very simple and efficient DNN model. The experimental data used to develop and test the model was obtained through Torsional Shear (TS) tests on soil samples. The model demonstrated high accuracy, with an average R² value of 0.9788 for testing and 0.9944 for training.

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Profiled delivery of bicarbonate during weekly cycle of hemodialysis

Pietribiasi Mauro, Leypoldt John K., Wieliczko Monika, Twardowska-Kawalec Malgorzata, Debowska Malgorzata, Malyszko Jolanta, Waniewski Jacek

Biocybernetics and Biomedical Engineering

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2024

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Vol. 44, no. 4

836--843

EN

Background: Delivery of bicarbonate during hemodialysis (HD) is aimed at correcting metabolic acidosis in end-stage renal disease patients. We tested modified prescriptions of bicarbonate concentration in dialysis fluid (CD, bic), aimed to achieve an optimal pre-dialytic bicarbonate plasma concentration (CP,bic). Methods: We used a mathematical model to prescribe individualized HD treatments consisting of 1) adjustment of CD,bic to get the pre-dialytic CP,bic in a prescribed range, 2) increase of bicarbonate load before the long interdialytic break, and 3) a single step of increase in CD,bic after two hours. The outcomes were tested in 24 stable HD patients, monitored during a week of standard HD (Test Week) and a week of modified treatment (Intervention Week). Results: The response to the model-based prescription was different whether the average CD,bic during the Intervention Week was higher or lower than the constant value used for the Test Week. For patients with lower average CD,bic during the Intervention Week, a significant fraction achieved the target (22 ≤ CP,bic ≤ 24 mEq/L). In the group with higher average CD,bic, the interventions were effective only in increasing post-dialytic CP,bic. The simple step-increase profile was effective in linearizing the intradialytic increase in bicarbonate and decreasing the amount of time spent by patients at high plasma CP,bic. Conclusions: The interventions were effective mostly in patients who needed to lower their pre-dialytic CP,bic. The resistance of the system to increasing pre-dialytic CP,bic in other patients might be caused by modifications of breathing or in hydrogen generation that were not accounted for by our model.

20

Thermal Operating Window in Selective Laser Melting Processes

Kozak Jerzy, Zakrzewski Tomasz, Witt Marta, Dębowska-Wąsak Martyna

Transactions on Aerospace Research

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2023

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Nr 4 (273)

18--32

EN

Selective laser melting (SLM) is one of the most effective methods of additive manufacturing (AM). It is used to manufacture products with very complex geometries using a wide range of materials. Practical process conditions are limited by the occurrence of undesirable melting instabilities that degrade the surface quality and lead to product defects. These disadvantages are related to the thermal limitations of the SLM process. The lower thermal limit is due to the need to completely melt the powder layer and partially remelt the underlying layer again to ensure proper bonding between the layers. Exceeding the upper thermal limit in the molten metal pool may cause extensive evaporation, boiling and ejection of molten metal droplets outside the melting area. The article presents an approach and methodology that enable the determination of thermal limits and the operating window of SLM/selective laser sintering (SLS) processes in a relatively simple way. The studies have been performed using various settings of SLM process parameters. The usefulness of the preliminary determination of thermal limitations and approximate prediction of operating window of SLM has been confirmed experimentally and by more accurate computer simulation.