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1

Availability analysis of vertical milling centre using Markov approach and Monte Carlo simulations

Kumar Girish, Mishra Ravi, Khan Tayyab

Safety and Reliability of Systems and Processes

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2023

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Summer Safety and Reliability Seminar 2023

117--130

EN

The purpose of this article is to investigate the availability of vertical machining centre using a Markovian technique and Monte Carlo simulation (MSC). Availability is a critical performance metric for industrial systems. Conventional methodologies focus for steady-state availability evaluation of mechanical systems. The research analyses transient availability assessment for four different system configurations. Monte Carlo simulation modelling is used to compare the results and future scope is suggested to use the developed MCS based algorithms/codes for non-exponential (time dependant) failure and repair time distributions. The research also investigates the influence of active and passive redundancy on availability, indicating that for the vertical machining centre, parallel architecture with standby redundancy outperforms active load sharing. The chapter includes a sensitivity study that modifies the repair rates of the ball screw and sub-assembly to make the component selection process easier for engineers. The authors believe that this chapter will be useful to maintenance and practising engineers because it will assist them in making informed decisions about system availability, developing maintenance/replacement policies, and determining the repair level required to achieve the desired system availability.

2

Assessment of the potential of using CNG to power up passenger cars in Poland

Kryzia Dominik, Pepłowska Monika

Polityka Energetyczna

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2023

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T. 26, z. 4

209--220

EN

This article presents the results of an assessment of the potential for the use of CNG in Poland as a fuel for passenger cars powered by an internal combustion engine fuelled by petrol or diesel. The basis for assessing the potential was an analysis of the economic efficiency of converting a passenger car fuelled by petrol or diesel to a dual-fuel vehicle by installing a CNG system. On the basis of available literature data, the vehicle structure was characterised using the following criteria: vehicle age, engine capacity, car-segment, type of fuel used and unladen vehicle mass. The average fuel consumption (petrol or diesel) of the vehicle before conversion was determined on the basis of specially developed statistical models. The conversion and operating costs of a vehicle fuelled with conventional fuel and with CNG (after vehicle conversion) were estimated on the basis of a stochastic simulation model using probability density distributions of vehicle parameters and the Monte Carlo method. The vehicle parameters were estimated so that the obtained set of vehicles reflected the actual structure of passenger cars in Poland. The estimated costs of vehicle conversion (purchase and installation of a CNG system) and its subsequent operating costs made it possible to assess the economic efficiency of the car conversion process. The potential use of CNG as a fuel for combustion cars was estimated by comparing the operating costs of a vehicle before conversion and the operating costs of a vehicle after conversion, taking into account the costs of conversion. Analogous calculations were carried out for the conversion of a vehicle to run on LPG, i.e. the most important competitor to CNG. At the current CNG fuel price of over 9.50 PLN/m3, the installation of a CNG system in passenger cars in Poland is not economically viable. Taking into account current fuel prices, the installation of a CNG system will start to be economically efficient for a small number of vehicles when the CNG price is 4 PLN/m3 lower than the current price. Conversion most often has a positive economic effect when it takes place in cars with a petrol-fuelled engine characterised by high fuel consumption and an average annual mileage of more than 20,000 kilometres.

PL

Artykuł prezentuje wyniki oceny potencjału wykorzystania CNG w Polsce jako paliwa do zasilania samochodów osobowych napędzanych silnikiem spalinowym zasilanym beznyną lub olejem napędowym. Podstawą do oceny potencjału była analiza efektywności ekonomicznej konwersji samochodu osobowego zasilanego benzyną lub olejem napędowym na pojazd dwupaliwowy polegający na montażu instalcji CNG. Na podstawie dostępnych danych literaturowych scharakteryzowano strukturę pojazdów za pomocą następujących kryteriów: wiek pojazdu, pojemność silnika, autosegment, rodzaj stosowanego paliwa, masa własna. Średnie zużycie paliwa (benzyny lub oleju napędowego) przez pojazd przed konwersją zostało określone na podstawie specjalnie opracowanych modeli statystycznych. Koszty konwersji i eksploatacji pojazdu zasilanego paliwem konwencjonalnym oraz instalacja CNG (po konwersji pojazdu) oszacowano na podstawie stochastycznego modelu symulacyjnego wykorzystującego rozkłady gęstości prawdopodobieństwa parametrów pojazdów oraz metodę Monte Carlo. Parametry pojazdów estymowano tak, aby otrzymany zbiór pojazdów odzwierciedlał rzeczywistą strukturę samochodów osobowych w Polsce. Oszacowane koszty konwersji pojazdu (zakup i montaż instalacji CNG) oraz jego późniejszej koszty eksploatacji umożliwiły ocenę efektywności ekonomicznej procesu konwersji samochodu. Potencjał wykorzystania CNG jako paliwa dla samochodów spalinowych został oszacowany poprzez porównanie kosztów eksploatacji pojazdu przed konwersją i kosztów eksploatacji pojazdu po konwersji z uwzględnieniem kosztów jej przeprowadzenia. Analogiczne obliczenia prrzeprowadzono dla wariantu konwersji pojazdu na napęd zasilany LPG to jest paliwa będącego najważniejszym konkurentem dla CNG.

3

An evaluation of the potential of the conversion of passenger cars powered by conventional fuels into electric vehicles

Kryzia Dominik, Kryzia Katarzyna

Polityka Energetyczna

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2023

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T. 26, z. 3

171-186

EN

The aim of this article is to assess the potential of converting gasoline-powered passenger cars into electric vehicles in Poland. Based on the available literature data, the vehicle structure was classified using the following criteria: vehicle age, engine capacity, car segment, type of fuel used, and curb weight. The average fuel and electric energy consumption values per vehicle before and after conversion were determined using specially developed statistical models. The conversion and operation costs of a conventionally fueled vehicle and an electric vehicle (after conversion) were estimated using a stochastic simulation model employing probability density distributions of vehicle parameters and the Monte Carlo method. Vehicle parameters were estimated to reflect the real structure of passenger cars in Poland. The estimated costs of converting a gasoline-powered vehicle to an electric vehicle (including the purchase and installation of an electric motor and battery) and its subsequent operating costs enabled the assessment of the economic efficiency of the car conversion process. The potential for converting gasoline-powered cars to electric vehicles was estimated by comparing the operating costs of the vehicle before and after conversion, taking into account the costs of the conversion itself. The potential of the studied conversion process amounted to 535,000 vehicles, which would generate an annual electricity demand of 1,746.36 GWh with electricity prices of 0.6 PLN/kWh. The conversion is economically viable mainly in passenger cars with a spark engine (more than 90% of cases).

PL

Celem artykułu jest ocena potencjału konwersji samochodów osobowych napędzanych silnikiem spalinowym na samochody elektryczne w Polsce. Na podstawie dostępnych danych literaturowych scharakteryzowano strukturę pojazdów za pomocą następujących kryteriów: wiek pojazdu, pojemność silnika, autosegment, rodzaj stosowanego paliwa, masa własna. Średnie zużycie paliwa i energii elektrycznej przez pojazd przed i po konwersji zostało określone na podstawie specjalnie opracowanych modeli statystycznych. Koszty konwersji i eksploatacji pojazdu zasilanego paliwem konwencjonalnym oraz energią elektryczną (po konwersji pojazdu) oszacowano na podstawie stochastycznego modelu symulacyjnego wykorzystującego rozkłady gęstości prawdopodobieństwa parametrów pojazdów oraz metodę Monte Carlo. Parametry pojazdów estymowano tak, aby otrzymany zbiór pojazdów odzwierciedlał rzeczywistą strukturę samochodów osobowych w Polsce. Oszacowane koszty konwersji pojazdu spalinowego na elektryczny (zakup i montaż silnika elektrycznego i baterii akumulatorów) oraz jego późniejszej koszty eksploatacji umożliwiły ocenę efektywności ekonomicznej procesu konwersji samochodu. Potencjał konwersji samochodów spalinowych na elektryczne został oszacowany poprzez porównanie kosztów eksploatacji pojazdu przed konwersją i kosztów eksploatacji pojazdu po konwersji z uwzględnieniem kosztów jej przeprowadzenia. Potencjał badanego procesu konwersji wyniósł 535 tysięcy sztuk pojazdów, co wygeneruje roczne zapotrzebowanie na energię elektryczną na poziomie 1746,36 GWh przy cenie energii elektrycznej na poziomie 0,6 zł/kWh. Konwersja jest ekonomicznie opłacalna głównie w samochodach osobowych z silnikiem iskrowym (ponad 90% przypadków).

4

Study of a Compton backscattering wall defects detection device using the Monte Carlo method

Qin Xuan, Yang Jianbo, Du Zhengcong, Xu Jie, Li Rui, Li Hui, Liu Qi

Nukleonika

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2023

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Vol. 68, No. 2

57--63

EN

In view of the shortcomings of traditional wall defect detection methods, such as small detection range, poor accuracy, non-portable device, and so on, a wall defects detection device based on Compton backscattering technology is designed by Monte Carlo method, which is mainly used to detect the size and location information of defects in concrete walls. It mainly consists of two parts, the source container and the detection system: first, through the simulation and analysis of the parameters such as the receiving angle of thebackscattered particles and the rear collimating material of the detector, the influence of the fluorescent X-ray peak of the detector collimating material on the backscattered particle counts is eliminated and the detected error is reduced; second, the ring array detector design, compared with single array detector and surface array detector, can facilitate real-time detection of defect orientation, expanding the single scan range and improving the detection efficiency. After simulation and comparative analysis, the relevant optimal parameters are obtained: the object is detected using a Cs-137 γ-ray source with an activity of 6 mCi, and a ring detector consisting of four 0.5-inch cube-shaped CsI scintillator detectors is placed at 150° to receive the backscattered photons. The simulation analysis using the Monte Carlo FLUKA program showed that the maximum depth of wall defect detection is 8 cm, the maximum error fl uctuation range of defect depth and thickness is ±1 cm, the overall device weight is <20 kg, and the measurement time is <5 min.

5

A risk assessment method of aircraft structure damage maintenance interval considering fatigue crack growth and detection rate

Zhang Zhuzhu, Mao Haitao, Liu Yulin, Jiao Peng, Hu Wenlin, Shen Pei

Eksploatacja i Niezawodność

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2023

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Vol. 25, no. 1

art. no. 3

EN

The accurate assessment of aircraft structure damage risk is the premise of establishing reasonable, economic and reliable maintenance intervals. While many studies have proposed damage risk assessment methods for aircraft structures, these methods lack the quantification of risk. This paper proposed a risk assessment method of aircraft structure damage maintenance interval considering fatigue crack growth rate and crack detection rate. The damage process of aircraft structure was simulated by Monte Carlo simulation to realize the quantitative assessment of aircraft structure damage risk and maintenance interval. Taking an aircraft fleet as an example, the damage risk of its wing structure was simulated and analyzed. The results show that if the risk is controlled within a reasonable range, the maintenance interval should be shortened to 16 flight hours. At the same time, through the analysis of the risk classification standard and the crack detection rate, the quantitative evaluation of the risk classification standard was realized.

6

Evaluation of the Effect of Uncertainties on the Acoustic Behavior of a Porous Material Located in a Duct Element Using the Monte Carlo Method

Hannachi Hanen, Trabelsi Hassen, Kani Marwa, Taktak Mohamed, Chaabane Mabrouk, Haddar Mohamed

Archives of Acoustics

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2023

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Vol. 48, No. 1

81--91

EN

When studying porous materials, most acoustical and geometrical parameters can be affected by the presence of uncertainties, which can reduce the robustness of models and techniques using these parameters. Hence, there is a need to evaluate the effect of these uncertainties in the case of modeling acoustic problems. Among these evaluation methods, the Monte Carlo simulation is considered a benchmark for studying the propagation of uncertainties in theoretical models. In the present study, this method is applied to a theoretical model predicting the acoustic behavior of a porous material located in a duct element to evaluate the impact of each input error on the computation of the acoustic proprieties such as the reflection and transmission coefficients as well as the acoustic power attenuation and the transmission loss of the studied element. Two analyses are conducted; the first one leads to the evaluation of the impacts of error propagation of each acoustic parameter (resistivity, porosity, tortuosity, and viscous and thermal length) through the model using a Monte Carlo simulation. The second analysis presents the effect of propagating the uncertainties of all parameters together. After the simulation of the uncertainties, the 95% confidence intervals and the maximum and minimum errors of each parameter are computed. The obtained results showed that the resistivity and length of the porous material have a great influence on the acoustic outputs of the studied model (transmission and reflection coefficients, transmission loss, and acoustic power attenuation). At the same time, the other physical parameters have a small impact. In addition, the acoustic power attenuation is the acoustic quantity least impacted by the input uncertainties.

7

Neutron conversion coefficients of ambient dose equivalent and personal dose equivalent

Al Kanti Hassan, El Hajjaji Otman, El Bardouni Tarek, Mohammed Maged

Polish Journal of Medical Physics and Engineering

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2022

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Vol. 28, Iss. 1

52--59

EN

Introduction: This work aims to calculate the ambient and personal dose equivalent conversion coefficients. Material and methods: The conversion coefficients have been calculated using MC simulation. Additionally, this paper proposes a new method that depends on an analytical approach. Results: The obtained results in good agreement between MC and an analytical approach were observed. The obtained results were compared to those published in ICRU 57 report. Conclusions: We deduced that the analytical approach is as effective and suitable as the MC simulation to calculate the operational quantity conversion coefficients.

8

Uncertainty analysis of operational conditions in selective artificial ground freezing applications

Zueter Ahmad, Akhtar Saad, Sasmito Agus

Journal of Sustainable Mining

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2022

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Vol. 21, iss. 3

169--179

EN

Artificial ground freezing (AGF) systems are susceptible to uncertain parameters highly affecting their performance. Particularly, selective artificial ground freezing (S-AGF) systems involve several uncertain operational conditions. In this study, uncertainty analysis is conducted to investigate four operational parameters: 1) coolant inlet temperature, 2) coolant flow rate, 3) pipes emissivity, and 4) pipes eccentricity. A reduced-order model developed and validated in our previous work for field-scale applications is exploited to simulate a total of 5,000 cases. The uncertain operational parameters are set according to Monte Carlo analysis based on field observations of a field-scale freeze-pipe in the mining industry extending to 460 m below the ground surface. The results indicate that the freezing time can range between 270 and 350 days with an average of 310 days, whereas the cooling load per one freeze-pipe ranges from 90 to 160 MWh, with an average of 129 MWh. Furthermore, it is observed that the freezing time and energy consumed are mostly dominated by the coolant inlet temperature, while energy dissipated in the passive zone (where ground freezing is not needed) is mostly affected by pipes emissivity. Overall, the conclusions of this study provide useful estimations for engineers and practitioners in the AGF industry.

9

Reliability-Based Assessment of Galloping Instability of Thin-Walled Steel Beams

Nguyen Huu Anh Tuan

Civil and Environmental Engineering Reports

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2022

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Vol. 32, no. 2

23--35

EN

Galloping instability relating to cross-wind vibrations can be found in flexible and lightly damped structures. In the present paper, the reliability of a thin-walled steel beam in maintaining its galloping stability was examined using a probabilistic approach. The analysis considered random variation in the cross-sectional geometrical properties of the beam, the material elastic modulus, the structural damping and the wind speed. A large number of Monte Carlo simulations were performed with normal and Gumbel distributions applied to the random variables to determine the probability distribution function of the safety margin. The limit state is considered violated when the wind speed exceeds the onset wind velocity of galloping, resulting in the aerodynamic damping being greater than the structural damping. It was shown by a conventional codified safety factor method that the beam was robust enough for galloping stability. By contrast, the probability-based assessment revealed that the beam failed to achieve the target reliability index in case the coefficient of variation of wind speed was greater than 5%. The analysis results suggested that the code-satisfied slenderness of the beam should be reduced by a factor of 1.5-1.7 under the action of wind speed with a coefficient of variation in the range 30-40%.

10

A Novel FE/MC-based Mathematical Model of Mushy Steel Deformation with GPU Support

Hojny Marcin, Dębiński Tomasz

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 2

735--742

EN

The paper presents the results of work leading to the construction of a spatial hybrid model based on finite element (FE) and Monte Carlo (MC) methods allowing the computer simulation of physical phenomena accompanying the steel sample testing at temperatures that are characteristic for soft-reduction process. The proposed solution includes local density variations at the level of mechanical solution (the incompressibility condition was replaced with the condition of mass conservation), and at the same time simulates the grain growth in a comprehensive resistance heating process combined with a local remelting followed by free/controlled cooling of the sample tested. Simulation of grain growth in the entire computing domain would not be possible without the support of GPU processors. There was a 59-fold increase in the computing speed on the GPU compared to single-threaded computing on the CPU. The study was complemented by examples of experimental and computer simulation results, showing the correctness of the adopted model assumptions.

11

Numerical modelling of modular high-temperature gas-cooled reactors with thorium fuel

Oettingen Mikołaj, Cetnar Jerzy

Nukleonika

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2021

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Vol. 66, No. 4

133--138

EN

The volumetric homogenization method for the simplified modelling of modular high-temperature gas-cooled reactor core with thorium-uranium fuel is presented in the paper. The method significantly reduces the complexity of the 3D numerical model. Hence, the computation time associated with the time-consuming Monte Carlo modelling of neutron transport is considerably reduced. Example results comprise the time evolutions of the effective neutron multiplication factor and fissionable isotopes (233U, 235U, 239Pu, 241Pu) for a few configurations of the initial reactor core.

12

Gamma radiation calculations and gamma blocker design for the high-energy beam transport region of the European Spallation Source

Szymczyk Karol S., Wronka Sławomir

Nukleonika

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2021

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Vol. 66, No. 3

99--102

EN

The purpose of this paper is to present the Monte-Carlo calculations performed to design a special element called gamma blocker (GB), necessary to stop the gamma radiation in the Accelerator-to-Target (A2T) section of European Spallation Source (ESS) linac. Very high levels of gamma radiation emitted backward from the activated target through the beam pipe could effectively block any human intervention close to the beam transport system. The residual dose rate in the linac tunnel was calculated without and with different GBs as a function of time. The fi nal GB material and dimensions are proposed.

13

Comparison of statistical versus stochastic models for Work Index determination in quartz-marble mixtures

Perez Sebastián, Vargas Juan, Mellado Miguel, Quevedo Caro Ricardo, Jarufe Juan, Hurtado Cruz Juan Pablo, Muñoz Lagos Angélica Patricia, Jara Muñoz Pamela Paz

Mining Science

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2021

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Vol. 28

127--140

EN

The required work for ore trituration is represented by the Bond Work Index value and is determined by the grindability test for ball mills. This article examines the grinding behavior of ore blends with different mechanical properties in standard ball mills. The goal of this research was to compare statistic and stochastic models of the Work Index value for mixtures of quartz and marble at different proportions of each material. Quartz and marble bearing rocks were selected for this study due to the high difference between the Work Index value of each material, making the variability of the results more evident. Work Index values obtained for each mixture are shown, from which a deterministic model was proposed defined by data regression. The novelty of this research lies in the non-linear model, which was the best fit for the Work Index value of the quartz-marble blends. Our methodology allows us to build more accurate models and can be used for quartz-marble blends and other materials.

14

Klein-Nishina formula and Monte Carlo method for evaluating the gamma attenuation properties of Zn, Ba, Te and Bi elements

Al-Buriahi M. S., Alrowaili Z. A., Ezzine Safa, Olarinoye I. O., Alomairy Sultan, Mutuwong C., Tonguç B. T.

Materials Science Poland

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2021

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Vol. 39, No. 2

219--226

EN

In this work, the Klein–Nishina (K–N) approach was used to evaluate the electronic, atomic, and energy-transfer cross sections of four elements, namely, zinc (Zn), tellurium (Te), barium (Ba), and bismuth (Bi), for different photon energies (0.662 MeV, 0.835 MeV, 1.170 MeV, 1.330 MeV, and 1.600 MeV). The obtained results were compared with the Monte Carlo method (Geant4 simulation) in terms of mass attenuation and mass energy-transfer coefficients. The results show that the K–N approach and Geant4 simulations are in good agreement for the entire energy range considered. As the photon energy increased from 0.662 MeV to 1.600 MeV, the values of the energy-transfer cross sections decreased from 81.135 cm2 to 69.184 cm2 in the case of Bi, from 50.832 cm2 to 43.344 cm2 for Te, from 54.742 cm2 to 46.678 cm2 for Ba, and from 29.326 cm2 to 25.006 cm2 for Zn. The obtained results and the detailed information of the attenuation properties for the studied elements would be helpful in developing a new generation of shielding materials against gamma rays.

15

Opportunistic maintenance strategy of a Heave Compensation System for expected performance degradation

Zhang Chao, Qian Yujie, Dui Hongyan, Wang Shaoping, Chen Rentong, Tomovic Mileta M.

Eksploatacja i Niezawodność

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2021

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Vol. 23, no. 3

512--521

EN

In the marine industry, heave compensation systems are applied to marine equipment to compensate for the adverse effects of waves and the hydraulic system is usually used as the power system of heave compensation systems. This article introduces importance theory to the opportunistic maintenance (OM) strategy to provide guidance for the maintenance of heave compensation systems. The working principle of a semi-active heave compensation system and the specific working states of its hydraulic components are also first explained. Opportunistic maintenance is applied to the semi-active heave compensation system. Moreover, the joint integrated importance measure (JIIM) between different components at different moments is analyzed and used as the basis for the selection of components on which to perform PM, with the ultimate goal of delaying the degradation of the expected performance of the system. Finally, compared with conditional marginal reliability importance (CMRI)based OM, the effectiveness of JIIM-based OM is verified by the Monte Carlo method.

16

A numerical simulation method for a repairable dynamic fault tree

Xu Zhixin, Guo Dingqing, Wang Jinkai, Li Xueli, Ge Daochuan

Eksploatacja i Niezawodność

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2021

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Vol. 23, no. 1

34--41

EN

Dynamic fault trees are important tools for modeling systems with sequence failure behaviors. The Markov chain state space method is the only analytical approach for a repairable dynamic fault tree (DFT). However, this method suffers from state space explosion, and is not suitable for analyzing a large scale repairable DFT. Furthermore, the Markov chain state space method requires the components’ time-to-failure to follow exponential distributions, which limits its application. In this study, motivated to efficiently analyze a repairable DFT, a Monte Carlo simulation method based on the coupling of minimal cut sequence set (MCSS) and its sequential failure region (SFR) is proposed. To validate the proposed method, a numerical case was studied. The results demonstrated that our proposed approach was more efficient than other methods and applicable for repairable DFTs with arbitrary time-to-failure distributed components. In contrast to the Markov chain state space method, the proposed method is straightforward, simple and efficient.

17

Combined Probabilistic Methods for Droplet Drying Simulations

Wolak W., Drzewiński A., Marć M., Najder-Kozdrowska L., Dudek M. R.

Computational Methods in Science and Technology

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2021

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Vol. 27, No. 4

169--175

EN

The rapidly developing 3D printing and the related fabrication of ultra-thin layers in various industries have resulted in the need for theoretical methods for describing large-area systems of growing nanostructures. The specificity of these issues is the presence of multi-particle systems characterized by the coexistence of particles with a wide range of sizes typical for ions, nanoparticles, and their agglomerates. A particular example would be an aqueous nano-colloidal suspension drying on a substrate as a self-assembling deposit. It should be emphasized here that the development of deposit patterning control techniques is one of the most important challenges for the thin film industry. In this paper we show that probabilistic methods can be successfully used to model such systems. To this aim, the combined master equation and Monte Carlo methods were used for computer simulation of a drying droplet in the case of a low concentration salt solution.The novelty of this approach is to show the possibility of computer simulation for a microscopic system while simulating large-scale processes affecting microscopic processes. The numerical results were additionally supported by experimental data.

18

Research on electric vehicle charging load prediction and charging mode optimization

Zhang Zhiyan, Shi Hang, Zhu Ruihong, Zhao Hongfei, Zhu Yingjie

Archives of Electrical Engineering

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2021

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Vol. 70, nr 2

399--414

EN

To reduce the influence of the disorderly charging of electric vehicles (EVs) on the grid load, the EV charging load and charging mode are studied in this paper. First, the distribution of EV charging capacity and state of charge (SOC) feature quantity are analyzed, and their probability density function is solved. It is verified that both EV charging capacity and SOC obey the skew-normal distribution. Second, considering the space-time distribution characteristics of the EV charging load, a method for charging load prediction based on a wavelet neural network is proposed, and compared with the traditional BP neural network, the prediction results show that the error of the wavelet neural network is smaller, and the effectiveness of the wavelet neural network prediction is verified. The optimization objective function with the lowest user costs is established, and the constraint conditions are determined, so the orderly charging behavior is simulated by the Monte Carlo method. Finally, the influence of charging mode optimization on power grid operation is analyzed, and the result shows that the effectiveness of the charging optimization model is verified.

19

Cellular Automata-based computational library for development of digital material representation models of heterogenous microstructures

Boguń Konrad, Sitko Mateusz, Mojżeszko Mateusz, Madej Łukasz

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 2

335--349

EN

The development of an efficient numerical approach for the generation of a wide range of heterogeneous microstructures models with the application of the lean workflow concept is presented in the paper. First, the idea and implementation details of the developed cellular automata-based computational library allowing the development of digital material representation models within a workflow are presented in the paper. Such an approach provides the desired flexibility in the generation of various digital models of heterogenous microstructures. Therefore, the proposed library is mostly implemented within the object-oriented C + + programming language with the assumption of modularity. In this case, the main part of the application consists of classes and methods, which can be treated like base elements to be inherited and extended in other libraries. Each additional dynamic link library implements particular algorithms for the generation of specific microstructure features in the digital model within the unified data structures that allow the application of the workflow concept. The set of developed libraries and their assumptions are described as case studies to show the capabilities of the presented solution. Finally, examples of practical applications of the developed library in the full-field numerical simulations of complex material deformation are presented at the end of the paper.

20

Monte Carlo characterization of the gold nanoparticles dose enhancement and estimation of the physical interactions weight in dose enhancement mechanism

Mohammadzadeh Mohammad, Ghiasi Hosein

Polish Journal of Medical Physics and Engineering

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2020

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Vol. 26, Iss. 4

217--223

EN

Radiosensitization of the cancer cells by the heavy atoms of nanoparticles was the subject of some studies. But, the physical characterization to determine the weight of all interactions hasn’t been made numerically. The aim of this study was to calculate and compare the dose enhancement (DE) for different energies. The Monte Carlo simulation method was used in the current study. The influence of gold nanoparticles (GNP) size, beam quality, the GNP concentration, and dose inhomogeneity on the radiosensitization by DE was studied. A 35% increase in the photoelectric effect was observed while energy decreased from 18 MV to 300 kV. In the microscopic study which DE calculated in 30 μm from a single GNP, a 79% decreasing in DE within the first 1μm was seen and it declined to 2% in 30 μm from the GNP center. The effect was observed at small distances only. Our study revealed that the dose inhomogeneity around a nanoparticle is the main and very strong effect of DE on a macroscopic scale. In the location which 35% DE occurs most malignant cells survival will be effectively reduced. Our research indicates the need for further research.