Articles de revues : « Numerical parameters extraction »

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Liu, Jiajia, Jianliang Gao, Ming Yang, Dan Wang et Liang Wang. « Numerical Simulation of Parameters Optimization for Goaf Gas Boreholes ». Advances in Civil Engineering 2019 (10 janvier 2019) : 1–13. http://dx.doi.org/10.1155/2019/3891080.

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In view of the ground drilling of the N2206 working face in Shanxi Wangzhuang Coal Mine, the gas concentration is low and the extraction effect is not good. Fluent computational fluid dynamics software was used to simulate the ground extraction drilling position of the N2206 working face in the goaf (the distance from the top of the coal seam and the distance from the return to the wind). The numerical simulation results show that when the final hole of the ground extraction hole in the goaf is 16 m from the roof of the coal seam and the distance from the return air is 45 m, the extraction effect is optimal. The average extraction gas volume is 9.78 m3/min, and the average extraction gas concentration is 43.95%, the best extraction effect is obtained. After optimizing the ground drilling position in the goaf and combining with the site implementation, the maximum gas scouring amount of the extraction is 12.59 m3/min, which is 3.42 m3/min higher than the original. The maximum gas concentration of extraction was 63.54%, which was 28.82% higher than the original. After optimization, the gas concentration of the extraction is more than 30%, and the extraction effect is very good. Field application results further validate the reliability of theoretical analysis and numerical simulation results.

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Zidan, Mahmoud N., Nicola Everitt, Tawfik Ismail et Irene S. Fahim. « Organic Solar Cells Parameters Extraction and Characterization Techniques ». Polymers 13, n^o 19 (23 septembre 2021) : 3224. http://dx.doi.org/10.3390/polym13193224.

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Organic photovoltaic research is continuing in order to improve the efficiency and stability of the products. Organic devices have recently demonstrated excellent efficiency, bringing them closer to the market. Understanding the relationship between the microscopic parameters of the device and the conditions under which it is prepared and operated is essential for improving performance at the device level. This review paper emphasizes the importance of the parameter extraction stage for organic solar cell investigations by offering various device models and extraction methodologies. In order to link qualitative experimental measurements to quantitative microscopic device parameters with a minimum number of experimental setups, parameter extraction is a valuable step. The number of experimental setups directly impacts the pace and cost of development. Several experimental and material processing procedures, including the use of additives, annealing, and polymer chain engineering, are discussed in terms of their impact on the parameters of organic solar cells. Various analytical, numerical, hybrid, and optimization methods were introduced for parameter extraction based on single, multiple diodes and drift-diffusion models. Their validity for organic devices was tested by extracting the parameters of some available devices from the literature.

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Freeborn, Todd J., Brent Maundy et Ahmed Elwakil. « Numerical extraction of Cole-Cole impedance parameters from step response ». Nonlinear Theory and Its Applications, IEICE 2, n^o 4 (2011) : 548–61. http://dx.doi.org/10.1587/nolta.2.548.

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Anani, Nader, et Haider Ibrahim. « Performance Evaluation of Analytical Methods for Parameters Extraction of Photovoltaic Generators ». Energies 13, n^o 18 (15 septembre 2020) : 4825. http://dx.doi.org/10.3390/en13184825.

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This paper presents a succinct exploration of several analytical methods for extracting the parameters of the single-diode model (SDM) of a photovoltaic (PV) module under standard test conditions (STC). The paper investigates six methods and presents the detailed mathematical analysis leading to the development of each method. To evaluate the performance of these methods, MATLAB-based software has been devised and deployed to generate the results of each method when used to extract the SDM parameters of various PV test modules of different PV technologies. Similar software has also been developed to extract the same parameters using well-established numerical and iterative techniques. A comparison is subsequently made between the synthesized results and those obtained using numerical and iterative methods. The comparison indicates that although analytical methods may involve a significant amount of approximations, their accuracy can be comparable to that of their numerical and iterative counterparts, with the added advantage of a significant reduction in computational complexity, and without the initialization and convergence difficulties, which are normally associated with numerical methods.

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Sun, Xueping, Rui Ma, Shun Zhou, Xiuting Shao, Jin Cheng, Dabin Lin, Wen Wang et Weiguo Liu. « Fast, Accurate and Full Extraction of Coupling-of-Modes Parameters by Finite Element Method ». Crystals 12, n^o 5 (16 mai 2022) : 706. http://dx.doi.org/10.3390/cryst12050706.

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This paper presents a new numerical approach for the full extraction of the coupling-of-modes (COM) parameters by stationary and eigenfrequency analyses in the finite element method (FEM). This is a fast method extracting from the results of static analysis and eigenfrequency analysis. It avoids the long calculation time of admittance frequency response analysis, which is commonly used in extracting COM parameters. In addition to the usual COM parameters (velocity, reflection coefficient, transduction coefficient and capacitance), the phases of reflection and transduction coefficient can be also extracted with this method. The proposed method was applied to different cutting types LiNbO3 with different types of thicknesses in a varying interdigital transducer (IDT). These examples show that our approach has great potential in extracting all the COM parameters of the Rayleigh SAW for all kinds of IDT structures. Therefore, it is a fast, accurate, general and full extraction approach of COM parameters.

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Benahmida, Abdelaaziz, Noureddine Maouhoub et Hassan Sahsah. « Numerical approach for extraction of photovoltaic generator single-diode model parameters ». Computer Science and Information Technologies 2, n^o 2 (1 juillet 2021) : 58–66. http://dx.doi.org/10.11591/csit.v2i2.p58-66.

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In this work, a numerical approach has been proposed to estimate the five single-diode circuit model physical parameters of photovoltaic generators from their experimental current-voltage characteristics. Linear least square method has been used to solve the system of three linear equations to express the shunt resistance, the saturation current and the photocurrent as a function of the series resistance and the ideality factor. Two key points have been used to solve the system of two nonlinear equations to extract values of series resistance and ideality factor. The advantage of the proposed method with respect of existing numerical techniques is that use only two key points of the experimental characteristic and need only two initial guesses and does not use any approximation. To evaluate the proposed method, three PV generators data have been used to compare the experimental and the theoretical curves. The application of the proposed method provides a good agreement with the experimental.

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Singh, Surya Prakash, Nilesh K. Tiwari et M. Jaleel Akhtar. « Nondestructive Extraction of Parameters of Multilayered Media Using Terahertz Pulse Technique ». Frequenz 73, n^o 1-2 (28 janvier 2019) : 63–70. http://dx.doi.org/10.1515/freq-2018-0057.

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Abstract In this work, an efficient non-invasive terahertz pulse technique is proposed and investigated to determine the thickness and refractive index of each layer in an optically thick stratified media. A closed form formulations are derived for simultaneous extraction of the thickness and complex refractive index of each layer with the help of primary reflected signals from the multilayered structure. The proposed technique is numerically tested using a full wave electromagnetic simulator and is experimental verified in the millimeter wave frequency range by utilizing the power peaks corresponding to the primary reflected signals. The numerical and measured results of multilayered samples under test are in good agreement with the reference data. The proposed terahertz pulse technique can be used for non-destructive testing of the multilayered system existing in various industries.

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Salame, C. T. « Extraction of RDS(ON)of n-Channel Power MOSFET by Numerical Simulation Model ». Active and Passive Electronic Components 23, n^o 4 (2001) : 175–83. http://dx.doi.org/10.1155/apec.23.175.

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In this paper we present an original method for n-channel power MOSFET resistance extraction in the operation mode (RDS(ON)). The IDS=f(VDS) electrical characteristics measurements for the transistor and the Body-Drain junction are realized for the experimental determination and the extraction (by numerical analysis) of RDS(ON), respectively. Values of this resistance are extracted for different positive bias applied between the gate and the source (+VGS). Physicals parameters obtained from the numerical analysis are inspected, and results shows that the numerically analysed junction characteristic is in very good correlation with the electrical measurement

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Wesolowski, Miroslaw, Mariusz Ruchwa, Eduards Skukis et Andrejs Kovalovs. « Numerical and Experimental Extraction of Dynamic Parameters for Pyramidal Truss Core Sandwich Beams with Laminated Face Sheets ». Materials 13, n^o 22 (17 novembre 2020) : 5199. http://dx.doi.org/10.3390/ma13225199.

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Sandwich beams that are composed of laminated face sheets and aluminum pyramidal truss cores are considered to be essential elements of building and aerospace structures. In this paper, a methodology for the experimental and numerical analysis of such structures is presented in order to support their industrial application. The scope of the present research covers both the experimental and numerical extraction of the dynamic parameters of the sandwich beams. Vibration tests are performed while using an optical system for three-dimensional vibrations sensing. The in-plane and out-of-plane vibration modes can thus be examined. A detailed numerical model of the sandwich beam is developed, including an adhesive joint (an additional layer of material) between the parent components of the beam. The numerically predicted modal parameters (eigenfrequencies, mode shapes, modal loss factors) are comported with their corresponding experimentally-obtained values. The modal loss factors are predicted based on the strain energy method, for which a brief theoretical introduction is provided. The obtained experimental and numerical results coincide with good accuracy. The circumstances for possible model simplifications are provided depending on the solution objectives.

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Rodrigues, Michele, Victor Sonnenberg et João Antonio Martino. « Parameters Extraction from C-V Curves in Triple-Gate FinFET ». Journal of Integrated Circuits and Systems 3, n^o 2 (18 novembre 2008) : 77–81. http://dx.doi.org/10.29292/jics.v3i2.285.

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Methods to determine the effective oxide thickness (EOT), fin height (Hfin) and fin doping concentration (Nfin) through gate to drain/source capacitance as a function of the front and the back gate voltage curves in triple-gate nMOS FinFET are presented. The proposed methods were validated through three-dimensional numerical simulations and experimental measurements showing that these methods can be also applied in triple-gate nMOS FinFET devices as a powerful tool for experimental validation.

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Rahnema, Milad, Hamed Rahnema, Marcia D. Mcmillan, Ali Reza Edrisi et Hamid Rahnema. « Numerical Study of Single Well Vapor Extraction Process ». Journal of Petroleum Engineering 2016 (8 novembre 2016) : 1–9. http://dx.doi.org/10.1155/2016/8925190.

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Vapor extraction (Vapex) is an emerging technology to produce heavy oil and bitumen from subsurface formations. Single well (SW) Vapex technique uses the same concept of Vapex process but only with one horizontal well. In this process solvent is injected from the toe of the horizontal well with oil production at the heel section. The main advantage of SW-Vapex process lies in the economic saving and applicability in problematic reservoirs, where drilling of two horizontal wells is impractical. The performance of SW-Vapex seems to be comparable with dual horizontal Vapex process using proper optimization schemes. This study is grouped into two sections: (i) a screening study of early time operating performance of SW-Vapex and (ii) a sensitivity analysis of the effect of the reservoir and well completion parameters. Simulation results show that solvent injection rate can be optimized to improve oil production rate. Higher injection rates may not necessarily lead to increase in production. This study confirms that SW-Vapex process is very ineffective in reservoirs with high oil viscosity (more than 1,500 cp) and thin formations (less than 10 m).

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Tilley, Nele, et Bart Merci. « Numerical study of smoke extraction for adhered spill plumes in atria : Impact of extraction rate and geometrical parameters ». Fire Safety Journal 55 (janvier 2013) : 106–15. http://dx.doi.org/10.1016/j.firesaf.2012.10.022.

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De Oliveira, Naila Albertina, et Jose Antonio Rabi. « CONTINUOUS-FLOW EXTRACTION OF BIOCOMPOUNDS IN FIXED BED : INFLUENCE OF SWAPPING FROM DIRICHLET TO DANCKWERTS CONDITION AT INLET IN PHENOMENOLOGICAL MODELS ». Revista Brasileira de Engenharia de Biossistemas 15, n^o 4 (29 novembre 2021) : 538–60. http://dx.doi.org/10.18011/bioeng2021v15n4p538-560.

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Phenomenological models have increasingly become vital to bioprocess engineering. In continuous-flow biocompounds extraction models, diffusion requires an extra boundary condition at exit (usually null Neumann condition) while either Dirichlet or Danckwerts condition can be imposed at inlet. By taking an extant case study and with the help of an in-house lattice-Boltzmann simulator, this work numerically examines prospective effects of interchanging aforesaid inlet conditions. Trial simulations were performed for scenarios ranging from convective-dominant to diffusive-dominant. Extraction yields numerically simulated under each inlet condition were compared with experimental data. Expected shape of extraction yield curves was simulated whenever process parameters were properly provided and differences due to switching inlet conditions became evident only in diffusion-dominant extraction scenarios. At diffusivities of order 10-6 m2 s-1, numerical results suggest that Danckwerts boundary condition should be preferred at bed inlet.

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Li, Wenchao, Viet-Hung Vu, Zhaoheng Liu, Marc Thomas et Bruce Hazel. « Extraction of modal parameters for identification of time-varying systems using data-driven stochastic subspace identification ». Journal of Vibration and Control 24, n^o 20 (16 octobre 2017) : 4781–96. http://dx.doi.org/10.1177/1077546317734670.

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This paper presents a method for the extraction of modal parameters for identification of time-varying systems using Data-Driven Stochastic Subspace Identification (SSI-DATA). In practical applications of SSI-DATA, both the modal parameters and computational ones are mixed together in the identified results. In order to differentiate the structural ones from computational ones, a new method based on the eigen-decomposition of the state matrix constructed in SSI-DATA is proposed. The efficiency of the proposed method is demonstrated through numerical simulation of a lumped-mass system and experimental test of a moving robot for extracting excited natural frequencies of the system.

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Lipnitskaya, S. N., I. I. Dudko et I. G. Smirnova. « Numerical Simulation of Light Extraction from Remote Phosphor LED ». Reviews on Advanced Materials and Technologies 4, n^o 3 (2022) : 35–41. http://dx.doi.org/10.17586/2687-0568-2022-4-3-35-41.

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In this paper, light extraction from remote phosphor LEDs were calculated in Zemax OpticStudio. The dependence of the optical characteristics of the remote phosphor LED on the parameters of phosphor and its geometrical form was considered. In case of a thin plate as a remote phosphor, phosphor particle size, phosphor mass fraction and phosphor plate thickness were carefully analyzed. Furthermore, a plane-convex lens and Fresnel lens were also considered as geometrical form of remote phosphor. The simulation results show that color coordinates of LED, using remote phosphor plate (thickness 0.25 mm, mass fraction 30% and particle size 3 μm of phosphor), are the closest to D65 point on color space compared to other considered LEDs. The use of plane-convex lens (thickness 1 mm, radius of curvature 7 mm, base diameter 7 mm) as remote phosphor results in the maximum luminous flux compared to other forms.

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Zhang, Xiaoqiang, Fengyuan Zhou et Jiaxing Zou. « Numerical Simulation of Gas Extraction in Coal Seam Strengthened by Static Blasting ». Sustainability 14, n^o 19 (30 septembre 2022) : 12484. http://dx.doi.org/10.3390/su141912484.

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For mines with low permeability and high gas emissions, static blasting technology is used to pre-split the coal seam to increase the permeability and strengthen the gas extraction, which will significantly reduce the occurrence of gas accidents in mines. Taking Wangjialing Coal Mine as the research object, the mathematical model of fluid-solid is established. The numerical simulation software COMSOL is used to simulate the established mathematical model. Simultaneously, the factors affecting the efficiency of static blasting gas extraction are analyzed by adjusting the parameters. The results reveal a more significant drop in gas pressure with increasing time. At 10 d, 30 d, 90 d and 180 d, the extraction efficiency increases by 11.80%, 18.67%, 22.22% and 24.13% in comparison to conventional extraction. In studying the influence of expansion pressure and other factors on gas extraction during static blasting, it is found that the change of negative pressure has little effect on gas extraction. Static blasting can significantly reduce gas pressure and achieve safe coal mining, providing a basis of field application of efficient gas extraction in low gas mines.

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Zhang, Dangyu, Minbo Zhang, Shilong Zhang, Zichao Wang, Yan Jin et Rentao Liu. « Numerical Simulation of Effective Extraction Radius of Pre-Drainage Borehole Based on Coal Damage Model ». Sustainability 15, n^o 5 (2 mars 2023) : 4446. http://dx.doi.org/10.3390/su15054446.

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Borehole pre-drainage is an important technical means to control a coal mine gas disaster. In order to determine the optimal pre-drainage parameters of Dashucun mine, a coal damage permeability evolution model was established based on coal damage deformation, considering gas adsorption and desorption and the Klinkenberg effect, and a damage fluid-structure coupling model of coal seam containing gas was established by combining the coal seam deformation equation and the mass conservation equation. COMSOL software was used to simulate the influence of factors such as the initial permeability of coal seam, negative pumping pressure, aperture and pumping time on the effective pumping radius of pre-drainage borehole. The results show that the effect of negative pressure on the effective extraction radius can be ignored. The effect of borehole aperture, initial permeability of coal seam and extraction time on effective extraction radius is great, which conforms to the power function relationship, and the coefficient correlation value is high. The optimal extraction parameters of Dashucun mine are determined as borehole diameter 113 mm, coal seam permeability 1 × 10−17 m2, negative extraction pressure 30 kPa and extraction time 180 d. The research results can provide theoretical reference for the pre-drainage of gas in Dashucun mine.

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Zhao, Youxin, Qingjie Qi, Xinlei Jia, Yingjie Liu et Jingwen Zhang. « Numerical Simulation of Coal Spontaneous Combustion around a Borehole Induced by Negative Pressure Gas Drainage ». Geofluids 2021 (7 août 2021) : 1–11. http://dx.doi.org/10.1155/2021/3938243.

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The suction negative pressure is an important factor affecting the spontaneous combustion of coal around a borehole. Because the mechanism of suction negative pressure in the gas extraction process remains unclear, a constant suction negative pressure is often used in coal mines, leading to a low efficiency of gas extraction in deep coal seams. Moreover, the coal body easily undergoes spontaneous combustion during the extraction process, which is not conducive to safe mining. To study the effect of the suction negative pressure near the end sealing section, a numerical model of the combustion process around a borehole under the influence of suction negative pressure was established using COMSOL. The variation laws of the gas seepage velocity, oxygen concentration, and coal temperature in the borehole cycle were analyzed, and the gas suction negative pressure under different sealing parameters was optimized to ensure efficient gas extraction and prevent the spontaneous combustion of coal. The results showed that the negative pressure of extraction provides the power required for gas seepage into the borehole, and the gas flow rate increases with increasing negative pressure of extraction, exhibiting a linear growth trend. The range of the coal suffocation zone around the sealing section decreases with the increase in the negative pressure. With the extension of the gas extraction time, the oxygen concentration decreases rapidly, and the inflection point advances with the increase in the negative pressure. When the negative pressure of gas extraction is <40 kPa, the range of the high-temperature area around the block increases with the negative pressure of gas extraction. Based on the present situation of the spontaneous combustion induced by gas drainage in the Pingdingshan No. 10 Coal Mine, different sealing parameters should be set with different negative pressures of extraction, and the negative pressure of extraction should not exceed −18 kPa when the sealing depth is 20 m and the sealing length is 8 m in the 24130 working face. These parameter settings can help effectively prevent spontaneous combustion during the extraction process.

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CAI, J. H., N. SATOH, M. YANAGIDA et L. Y. HAN. « SUCCESSIVE LARGE PERTURBATION METHOD FOR THE EXTRACTION OF MORE ACCURATE EQUIVALENT-CIRCUIT-PARAMETERS IN SOLAR CELLS ». Journal of Nonlinear Optical Physics & ; Materials 19, n^o 04 (décembre 2010) : 637–43. http://dx.doi.org/10.1142/s0218863510005558.

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The numerical least-square fitting is a general method for the extraction of model parameter from experimental data. However, the method suffers from an initial value dependence problem when the method is used in I - V curve fitting. Recently we have proposed a successive large perturbation method (SLPM) to eliminate the initial value dependence problem. In this paper, we test the SLPM by comparing our results with previous published fitting results for various solar cells, such as traditional silicon solar cells and new type of organic solar cells and dye-sensitized solar cells. The method is available not only to the fitting for I - V curve, but also to the fitting for electrochemical impedance spectrum. Our test demonstrates that Newton-like method plus our SLPM is an accurate and robust method for the numerical extraction of equivalent circuit parameters in solar cells.

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Bloot, Rodrigo, Tiago A. Coimbra, Jorge H. Faccipieri et Martin Tygel. « Common-reflection-surface method in weakly anisotropic vertical transverse isotropic media ». GEOPHYSICS 83, n^o 3 (1 mai 2018) : C99—C113. http://dx.doi.org/10.1190/geo2017-0368.1.

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The extraction of kinematic parameters from wave propagation through traveltimes is one of the great challenges in seismic data processing. In this context, we modify the common-reflection-surface (CRS) traveltime to improve its accuracy and also interpret its parameters via paraxial ray theory in an anisotropic medium obtaining information about the wavefront curvatures measured at surface. The proposed method consists of searching for the best stacking parameters that fit the data set followed by the extraction of kinematic information from the measured waves. Numerical tests show the effectiveness of our assumptions and that the results obtained in the fitting and parameter extraction in anisotropic media achieve better accuracy than conventional CRS.

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Suleymanova, F. Sh, O. V. Nesterova et A. A. Matyushin. « Study of technological parameters and the numerical indicators of the quality of crude materials of canadian goldenrod herb (Solidago canadensis L.) ». Sechenov Medical Journal, n^o 3 (30 septembre 2018) : 64–68. http://dx.doi.org/10.47093/2218-7332_2018.3.64-68.

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The article presents the results of a study of technological parameters (speciﬁc mass, bulk mass, volume mass, porosity, quantity cavities between particles, free volume of a layer of the crude materials and coefficient of absorption of solvents) and individual the numerical indicators of the quality (moisture; ash residue: total and insoluble in 10% solution of hydrochloric acid; chopped crude materials; extraneous materials) of the Canadian goldenrod herb. The content of extractive substances was determine. The obtained data will be used in the technological process in the production of extraction preparations.

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Rudenko, Tamara, Sylvain Barraud, Yordan M. Georgiev, Vladimir Lysenko et Alexei N. Nazarov. « Electrical Characterization and Parameter Extraction of Junctionless Nanowire Transistors ». Journal of Nano Research 39 (février 2016) : 17–33. http://dx.doi.org/10.4028/www.scientific.net/jnanor.39.17.

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This article presents a review of various methods for extracting the key parameters of junctionless (JL) MOSFETs, namely, the threshold voltage, flat-band voltage, doping concentration, carrier mobility, and parasitic series resistance. The applicability and limitations of different methods are analyzed using numerical simulations and experimental data for planar and tri-gate nanowire JL transistors with various nanowire widths.

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Azzopardi, S., M. Trivedi, C. Zardini et K. Shenai. « Non-destructive extraction of technological parameters for numerical simulation of conventional planar punch-through IGBT ». Solid-State Electronics 44, n^o 11 (novembre 2000) : 1899–908. http://dx.doi.org/10.1016/s0038-1101(00)00184-2.

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Sandrolini, L., M. Artioli et U. Reggiani. « Numerical method for the extraction of photovoltaic module double-diode model parameters through cluster analysis ». Applied Energy 87, n^o 2 (février 2010) : 442–51. http://dx.doi.org/10.1016/j.apenergy.2009.07.022.

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Bechtold, T., D. Hohlfeld, E. B. Rudnyi et M. Günther. « Efficient extraction of thin-film thermal parameters from numerical models via parametric model order reduction ». Journal of Micromechanics and Microengineering 20, n^o 4 (22 mars 2010) : 045030. http://dx.doi.org/10.1088/0960-1317/20/4/045030.

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Wang, Yu-Lu, Wei Jiang et Yong-Hui Xie. « Numerical study into the effects of effective angle of attack motions on energy extraction performance of parallel foils ». Thermal Science 22, Suppl. 2 (2018) : 371–81. http://dx.doi.org/10.2298/tsci170731249w.

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The effects of different effective angle of attack motions on flapping foil are considered. Energy extraction characteristics of parallel foils with combined plunging and pitching motions at multiple working conditions are systematically analyzed. The energy extraction processes of dual foil at different effective angle of attack motions and reduced frequencies are simulated, respectively. In the range of parameters discussed in this paper, the increase of Ke improves the energy extraction performance of foil effectively. Every effective angle of attack motion has a frequency which can obtain the optimal extraction performance. The optimal energy extraction working condition is Ke = 2 and k = 0.8, where the extraction efficiency of dual foil achieves 25.8%. The synchronicity of the aerodynamic lift and the plunging motion is increased with increase in Ke. This paper provides a significant reference to the further study and popularization in engineering practice of parallel foils energy extraction.

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Vlasov, S. F., et Ye V. Moldavanov. « Effect of geological and technological parameters on the convergence in a stope ». Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu, n^o 6 (2021) : 16–22. http://dx.doi.org/10.33271/nvngu/2021-6/016.

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Purpose. To study regularities in changes in convergence of wall rocks along a setting line of the powered props depending upon the sandstone availability within the roof, mining depth, as well as its position relative to the coal seam along the length of the extraction column based on the results of numerical experiments and forecast probable zones of rigid settlement of the powered support units according to a longwall length at any moment of a stope arrangement along the extraction pillar in accordance with changes in geological and technological parameters. Methodology. The paper represents numerical experiments based upon 3D computer modelling of incremental stope advance within a layered transverse and isotopic rock mass while applying Solid Works Simulation 2019 software. Findings. The research results, concerning the nature of wall rock distribution value within a stope, are given. The results were obtained using incremental computer modelling of the longwall advance within a layered transverse and isotopic rock mass within the area of initial caving of the main roof. Originality. In the context of the Western Donbas mines, regularities of convergence value of wall rock distribution have been determined depending upon certain changes in such a system of geological and technological parameters as: availability of sandstone with 5 and 30 m thickness both within the immediate rock and at 30 m distance as well as nonavailability of sandstone within a roof; 215, 260 and 305 m changes in longwall length; 150, 300 and 450 m changes within a zone of initial caving of the main roof (1545 m) with 10 m increment of longwall distancing from an installation chamber at 1050 m distances. Practical value. The identified regularities of changes in convergence value make it possible to forecast probable zones of rigid settlement of the powered support units depending upon the longwall length at any moment of a stope location along the extraction pillar irrespective of mining depth. The abovementioned helps optimize the parameters of seam extraction for the conditions of the Western Donbas mines if required.

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Ibáñez, María José, Domingo Barrera, David Maldonado, Rafael Yáñez et Juan Bautista Roldán. « Non-Uniform Spline Quasi-Interpolation to Extract the Series Resistance in Resistive Switching Memristors for Compact Modeling Purposes ». Mathematics 9, n^o 17 (4 septembre 2021) : 2159. http://dx.doi.org/10.3390/math9172159.

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An advanced new methodology is presented to improve parameter extraction in resistive memories. The series resistance and some other parameters in resistive memories are obtained, making use of a two-stage algorithm, where the second one is based on quasi-interpolation on non-uniform partitions. The use of this latter advanced mathematical technique provides a numerically robust procedure, and in this manuscript, we focus on it. The series resistance, an essential parameter to characterize the circuit operation of resistive memories, is extracted from experimental curves measured in devices based on hafnium oxide as their dielectric layer. The experimental curves are highly non-linear, due to the underlying physics controlling the device operation, so that a stable numerical procedure is needed. The results also allow promising expectations in the massive extraction of new parameters that can help in the characterization of the electrical device behavior.

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Nguyen Dang Binh, Thanh, Dung Nguyen Trung et Duc Hong Ta. « MODELING OF ESSENTIAL OIL EXTRACTION PROCESS : APPLICATION FOR ORANGE, POMELO, AND LEMONGRASS ». Vietnam Journal of Science and Technology 56, n^o 4A (19 octobre 2018) : 182. http://dx.doi.org/10.15625/2525-2518/56/4a/12811.

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ABSTRACT - HCTN - 44In this study, the kinetic models of steam distillation of orange (Citrus Sinensis (L.) Osbeck), pomelo (Citrus grandis L.), and lemongrass (Cymbopogon Citratus) for the recovery of essential oils were developed. The model parameters were estimated based on experimental data and comprehensive kinetic mechanisms of the solid-liquid extraction process. Numerical results showed that, the extraction mechanism of the three materials were best fit to the Patricelli two-stage model in which the diffusion of the oil was followed by the washing step. Moreover, the model parameters obtained from the measured data reflected clearly the nature of the two-stage extraction at which the kinetic rate of the washing step (surface extraction) was higher than that of in-tissue diffusion step. Thus, the kinetics of the extraction processes obtained from the present work could be used for the scale-up of the extraction process operating at a large scale and for the purpose of process control as well.

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Wang, Wei, Zongxiang Li, Guangmin Zhao et Yujin Chen. « Coal and Gas Comining in the High-Gas Detong Mine, China : Analytical and Numerical Parameter Optimization of Gas Extraction Boreholes ». Advances in Civil Engineering 2022 (4 mars 2022) : 1–12. http://dx.doi.org/10.1155/2022/9552620.

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The upper corner gas overrun caused by goaf gas gushing in the high-gas mine can be mitigated by roof positioning of long boreholes in the goaf fracture zone, creating an artificial gas migration channel and achieving safe comining of coal and gas. This study numerically simulated the fracture evolution in the coal rock overlying goaf in workface #2-104 of the Detong Mine, China. Using the O-shaped circle theory and the FLAC3D commercial software package, the range parameters of goaf fracture zone gas-concentrated areas were obtained by defining the pressure relief coefficient, which provided a basis for the arrangement of holes in the goaf located at 15 m from the workface goaf collapse zone to the workface floor and 15–60 m from the structure zone to the workface. According to the obtained goaf parameters, the distribution and migration law in the goaf under the conditions of initial state and extraction with different roof borehole parameters were simulated by the FLUENT software. The optimal borehole location was 30 m from the floor and 25 m from the return airway. The field experiment with three boreholes arranged in the optimal extraction position provided the extraction concentration in the borehole above 30%, the gas extraction volume of 12 m3·min−1, and the concentration at the upper corner below 1%, which ensured safe coal and gas comining.

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Zhou, Junwei, Wenhui Yan, Lei Mei, Lixin Cong et Weichao Shi. « Principal Parameters Analysis of the Double-Elastic-Constrained Flapping Hydrofoil for Tidal Current Energy Extraction ». Journal of Marine Science and Engineering 10, n^o 7 (23 juin 2022) : 855. http://dx.doi.org/10.3390/jmse10070855.

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Taking the rigid NACA0012 airfoil as the object, the key structural parameters of the spring–mass system that govern the dynamics of the double-elastic-constrained flapping hydrofoil are numerically studied in this paper. A two-dimensional numerical model, based on the CFD software FINE/Marine, is established to investigate the influence of the spring stiffness coefficient, frequency ratio, and damping coefficient on the motion and performance of the flapping hydrofoil. This study demonstrates that when the structural parameters are adequately adjusted, the power factor exceeding 1.0 has been achieved, and the corresponding efficiency is up to 37.8%. Moreover, this system can start and work within a wide range of damping coefficients. However, the hydraulic efficiency and power coefficient are sensitive to the change in damping coefficient, so it is very necessary to design an appropriate power output. Lastly, the most obvious parameter affecting the energy acquisition performance is the spring stiffness coefficients. Frequency ratios in the two directions have little influence on the peak value of the power coefficient, but they will cause the change of damping coefficients of the peak point. The key structural parameters studied in this paper provide a useful guideline for an optimized design of this interesting system through searching for the best performance.

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SELLAI, A., et Z. OUENNOUGHI. « EXTRACTION OF ILLUMINATED SOLAR CELL AND SCHOTTKY DIODE PARAMETERS USING A GENETIC ALGORITHM ». International Journal of Modern Physics C 16, n^o 07 (juillet 2005) : 1043–50. http://dx.doi.org/10.1142/s0129183105007704.

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Details concerning the implementation of a versatile genetic algorithm are presented. Solar cell and Schottky diode model parameters are extracted based on the fitness of experimental data to theoretical curves simulated in the framework of certain physical processes and the use of this genetic algorithm. The method is shown to be a reliable alternative to conventional numerical techniques in fitting experimental data to model calculations and the subsequent determination of model related parameters. It is demonstrated, through two examples in particular, that some of the drawbacks associated with the conventional methods can be circumvented if a genetic algorithm is used instead. For instance, a good initial guess is not a critical requirement for convergence and an initial broad range for each of the fitting parameters is enough to achieve reasonably good fits.

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Simeonov, Evgeni, Zvezdelina Yaneva et Chavdar Chilev. « Extraction of Protodioscin from Tribulus terrestris-Optimisation of Kinetics and Modeling ». Revista de Chimie 71, n^o 12 (7 janvier 2021) : 56–66. http://dx.doi.org/10.37358/rc.20.12.8386.

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The aim of the present study was to establish the optimal conditions for protodioscin extraction from Tribulus terrestris plant and to investigate the possibilities of mathematical modeling of the process and calculation of the diffusion coefficients essential for the industrial scale-up and management of the extraction process. The kinetics of protodioscin extraction from Tribulus terrestris was experimentally studied at varying the solvent type (70% and 96% ethanol) and temperature (20�C, 30�C, 40�C). The optimal process conditions for these parameters were determined. The experimental results were mathematically modelled. Numerical solutions of the propsed in the study empirical model with constant and variable effective diffusivity in the solid phase, Deff, were obtained. The empirical model was based on comparative analyses with the Regular regime model solutions. It was established that the experimental data complied satisfactorily with the the resulting numerical solutions.

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Gaga, Ahmed, Fatima Errahimi, Fatima Cheddadi et Youssef Cheddadi. « Numerical approach for parameter extraction of a photovoltaic module based on datasheet and five parameters model ». International Journal of Digital Signals and Smart Systems 5, n^o 2 (2021) : 167. http://dx.doi.org/10.1504/ijdsss.2021.10036182.

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Cheddadi, Fatima, Youssef Cheddadi, Fatima Errahimi et Ahmed Gaga. « Numerical approach for parameter extraction of a photovoltaic module based on datasheet and five parameters model ». International Journal of Digital Signals and Smart Systems 5, n^o 2 (2021) : 167. http://dx.doi.org/10.1504/ijdsss.2021.114559.

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Li, Zhao Kun, Hua Mei Bian, Li Juan Shi et Xiao Tie Niu. « Multiobjective Topology Extraction of the Compliant Mechanisms ». Advanced Materials Research 971-973 (juin 2014) : 1941–48. http://dx.doi.org/10.4028/www.scientific.net/amr.971-973.1941.

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Homogenization or material distribution method based topology optimization will create final topologies in grey level image and saw tooth jump discontinuity boundaries that are not suitable for direct engineering practice, so it is necessary to extract the topological diagram. And a new topology extraction method for compliant mechanisms is presented. In the fist stage, the grey image is transferred into the black-and white finite element topology optimization results. The threshold value meeting to objective function is obtained so that each element is either empty or solid; in the second stage, the density contour approach is used by redistributing nodal densities to generate the smooth boundaries; in the third stage, Smooth boundaries are represented by parameterized B-spline curves whose control points selected from the viewpoint of stiffness and flexibility constitute the parameters ready to undergo shape optimization; Then shape optimization is executed to improve stress-based local performance, The parameters that present the outer shape of the compliant mechanism are used as design variables; In the final stage, simulations of numerical examples are presented to show the validity of the proposed method.

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Lin, Tsung-Chih, Ming-Jen Kuo et Alexandre Boyer. « Integrated Circuit Emission Model Extraction with a Fuzzy Logic System ». International Journal of Fuzzy System Applications 1, n^o 2 (avril 2011) : 17–28. http://dx.doi.org/10.4018/ijfsa.2011040102.

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This paper describes a novel technique for multiple parameter extraction of the S12X TEM cell model using a fuzzy logic system (FLS). The FLS is utilized to capture the circuit information and to extract the circuit parameters based on experiential knowledge. The proposed extraction technique uses both linguistic information (i.e., human-like knowledge and experience) and numerical data of measurement to construct the fuzzy macromodel. The simulation results confirm the validity and estimation performance of the equivalent circuit by the advocated design methodology.

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Ryazantsev, D. V., et V. P. Grudtsov. « Automatic Parameter Extraction Technique for MOS Structures by C-V Characterization Including the Effects of Interface States ». Measurement Science Review 16, n^o 5 (1 octobre 2016) : 266–72. http://dx.doi.org/10.1515/msr-2016-0033.

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Abstract An automatic MOS structure parameter extraction algorithm accounting for quantum effects has been developed and applied in the semiconductor device analyzer Agilent B1500A. Parameter extraction is based on matching the experimental C-V data with numerical modeling results. The algorithm is used to extract the parameters of test MOS structures with ultrathin gate dielectrics. The applicability of the algorithm for the determination of distribution function of DOS and finding the donor defect level in silicon is shown.

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Zhao, Zhen, Guangxiong Qin, Huijuan Chen, Linchao Yang, Songhe Geng, Ronghua Wen et Liang Zhang. « Numerical Simulation and Economic Evaluation of Wellbore Self-Circulation for Heat Extraction Using Cluster Horizontal Wells ». Energies 15, n^o 9 (30 avril 2022) : 3296. http://dx.doi.org/10.3390/en15093296.

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The heat extraction capacity of the self-circulation wellbore is usually small because of the limited heat exchange area. In the paper, the cluster horizontal well group technology was proposed to enhance the heat extraction capacity and decrease the unit cost. Based on the mathematical model of heat transfer, a numerical simulation model of wellbore self-circulation for heat extraction using cluster horizontal wells was established to study the influence of main factors on heat extraction capacity. The economic analysis of heat extraction and power generation was carried out according to the model of the levelized cost of energy. The results show that the enhancement of heat extraction capacity is limited after the injection rate exceeds 432 m3/d (1.59 MW/well). The inflection point of the injection rate can be determined as the design basis for injection-production parameters. When the thermal conductivity of formation increases from 2 to 3.5 W/(m·K), the heat extraction rate will increase 1.45 times, indicating that the sandstone reservoirs with good thermal conductivity can be preferred as the heat extraction site. It is recommended that the well spacing of cluster wells is larger than 50 m to avoid the phenomenon of thermal short circuit between wells, and the thermal conductivity of the tubing should be less than 0.035 W/(m·K) to reduce the heat loss of heat-carrying fluid in the tubing. Compared with a single well, a cluster horizontal well group can reduce the unit cost of heat extraction and power generation by 24.3% and 25.5%, respectively. The economy can also be improved by optimizing heat-carrying fluids and retrofitting existing wells.

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Kordubaylo, Aleksey, Boris Simonov et Yuri Pronkin. « STUDY OF STATIC AND DYNAMIC PARAMETERS OF HYDROCLEAVING DEVICE ». Interexpo GEO-Siberia 2, n^o 4 (2019) : 89–97. http://dx.doi.org/10.33764/2618-981x-2019-2-4-89-97.

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In the work current importance of creation of hole electro driven pulse seismic sources for treatment of productive collectors of oil and gas deposit in order to hydrocarbons extraction intensification is justified. Study results of transfer center of strike pulses to extracting column are represented. The center is represented with hydrocleaving device. Objectives of the work are: establishing of dependences of plunger dies thrust force of hydrocleaving device on static pressure of working liquid in chamber, discovering of optimal values of hydrostatic pressure for provision of maximal pressure pulses in the chamber. Analytical dependence of thrust force on pressure in the chamber is obtained. Values of static strain of pipe fragment with diameter 122mm and wall thickness 9 mm under action of calculated thrust force are determined by methods of numerical simulations. Strains of fragment of the same pipe are experimentally studied under action of prototype thrust force. It is established that at pressure in the chamber up to 10MPa pipe strain at action axis is elastic up to 1mm. Repeatability of physical and numerical measurements is within 10%. With further increasing of the pressure up to 40 MPa the strain is elastic plastic up to 2.2mm. Using the method of physical simulation, it is established that pressure pulses in hydrocleaving device reach maximal values (up to 12 MPa) when values of preliminary static pressure are from 17 MPa up to 21MPa. However, increasing of strike energy above 180 J do not influence on value of pulse pressure significantly. Previously the devices of such type were not studied and were not applied in dynamic working modes. In the work recommendations for construction change of hydrocleaver for improvement of its dynamic parameters are formulated.

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Qin, Zhenghan, Haisheng Shen, Yong Yuan, Zhixiong Gong, Zhongshun Chen et Yongqi Xia. « Determination of Gas Extraction Borehole Parameters in Fractured Zone on ‘Borehole in Place of Roadway’ Based on RSM-GRA-GA ». Processes 10, n^o 7 (21 juillet 2022) : 1421. http://dx.doi.org/10.3390/pr10071421.

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Large-diameter gas extraction borehole is considered an effective method by which to realize coal mine methane exploitation and outburst prevention. Efficient gas extraction can be achieved by selecting the right borehole parameters. In this paper, by comparing several conventional objective weighting methods, the PCA was used to assign the weights to the research indices, the optimization objective was reduced from multi-dimensional to one-dimensional with the help of the gray correlation analysis. The study of gas extraction effect under different borehole parameters based on the response surface model. Numerical simulations were used to analyze the mixed volume of gas extraction, the pure volume of extraction and the concentration in the upper corner after extraction under different schemes. Finally, a genetic algorithm degree model was used to solve the solution and determine the optimal arrangement of borehole parameters. The study shows that (1) the weight shares of borehole stratum, borehole diameter and borehole spacing were 0.385, 0.285 and 0.33, respectively, in the reduced dimensional analysis of the PCA. (2) Using the results of improved gray correlation analysis as a comprehensive evaluation value to measure the effect of gas extraction, the optimal range of the model was 28–30 m borehole level, 190–210 mm borehole diameter and 5.5–6.5 m borehole spacing. (3) Using the genetic algorithm to solve the model, we obtained the borehole layer 28.79 m, borehole diameter 199.89 mm, borehole spacing 5.76 m. The borehole gas extraction effect was good under this parameter. The extraction mixed volume was 129.8 m3/min, the extraction pure volume was 9.16 m3/min, the upper corner concentration was 0.52%, and the prediction accuracy of the model was 97.8%.

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Mochalskyy, S., D. Wünderlich, B. Ruf, P. Franzen, U. Fantz et T. Minea. « 3D numerical simulations of negative hydrogen ion extraction using realistic plasma parameters, geometry of the extraction aperture and full 3D magnetic field map ». Review of Scientific Instruments 85, n^o 2 (février 2014) : 02B301. http://dx.doi.org/10.1063/1.4824746.

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RASHEED, Mohammed, Suha SHIHAB et Taha RASHID. « Two Step and Newton- Raphson Algorithms in the Extraction for the Parameters of Solar Cell ». Al-Qadisiyah Journal Of Pure Science 26, n^o 1 (21 janvier 2021) : 143–54. http://dx.doi.org/10.29350/qjps.2021.26.1.1260.

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The goal of this work is to find a numerical solution of nonlinear solar cell equation. This equation has been instructed using a single-diode model. The proposed method consists of solving the equation using two iterative methods with the initial value . Moreover, the Newton's and Two-step methods are used to determine the required the current, the voltage, and the power of the PV cell in the procedure of the present research. Different values of load resistance have introduced with these methods. The obtained results appeard that the proposed method is the most efficient compare with NRM and all the calculations are achieved using Matlab program.

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Захаров, Александр, Aleksandr Zakharov, Андрей Пономарев et Andrey Ponomarev. « NUMERICAL SIMULATION OF THE PROCESS OF GEOTHERMAL LOW-POTENTIAL GROUND ENERGY EXTRACTION ». Construction and Architecture 3, n^o 2 (30 janvier 2016) : 0. http://dx.doi.org/10.12737/11001.

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The aim of our research is to study the interaction of energy foundations with the ground mass and to develop methods for their construction on the example of the city of Perm. Field studies of ground were carried out in a specially chosen pilot site to determine temperature distribution in the ground mass, change of ground-water level and physical-mechanical and thermal-physical characteristics of the ground mass. The diagrams of depth temperature distribution in the ground and its seasonal variations were obtained on the results of monitoring, and also the average groundwater level. To carry out numerical simulation, software-complex “GeoStudio” was selected. Its basic differential equation is the fundamental heat conduction equation with an internal heat source. The purpose of the numerical simulation was quantitative evaluation of the thermal energy extracted from different energy foundations under soil conditions in the city of Perm. By results of the spent numerical experiments the equations of regress and nomographs dependences of size of received thermal energy on geometrical parameters of the projected power bases to hydro-geological and climatic conditions of the Perm region are constructed

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Balasubadra, K., V. Rajamani et K. Sankaranarayanan. « 3D Numerical Modeling and Extraction of Noise Parameters of Uniformly Doped Metal-Semiconductor Field Effect Transistor Photodetector ». Journal of Computational and Theoretical Nanoscience 6, n^o 3 (1 mars 2009) : 561–70. http://dx.doi.org/10.1166/jctn.2009.1072.

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Daly, T., L. E. Myers et A. S. Bahaj. « Modelling of the flow field surrounding tidal turbine arrays for varying positions in a channel ». Philosophical Transactions of the Royal Society A : Mathematical, Physical and Engineering Sciences 371, n^o 1985 (28 février 2013) : 20120246. http://dx.doi.org/10.1098/rsta.2012.0246.

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The modelling of tidal turbines and the hydrodynamic effects of tidal power extraction represents a relatively new challenge in the field of computational fluid dynamics. Many different methods of defining flow and boundary conditions have been postulated and examined to determine how accurately they replicate the many parameters associated with tidal power extraction. This paper outlines the results of numerical modelling analysis carried out to investigate different methods of defining the inflow velocity boundary condition. This work is part of a wider research programme investigating flow effects in tidal turbine arrays. Results of this numerical analysis were benchmarked against previous experimental work conducted at the University of Southampton Chilworth hydraulics laboratory. Results show significant differences between certain methods of defining inflow velocities. However, certain methods do show good correlation with experimental results. This correlation would appear to justify the use of these velocity inflow definition methods in future numerical modelling of the far-field flow effects of tidal turbine arrays.

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Roy, P., P. Bhattacharya, P. K. Rout, S. Mukhopadhyay, N. Majumdar et S. Sarkar. « Effect of hole geometry on charge sharing and other parameters in GEM-based detectors ». Journal of Instrumentation 17, n^o 03 (1 mars 2022) : P03016. http://dx.doi.org/10.1088/1748-0221/17/03/p03016.

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Abstract Gas Electron Multipliers (GEM) are among the more prominent Micro-Pattern Gaseous Detectors (MPGDs) and widely used in high energy particle physics experiments and various related applications. Adoption of different production techniques lead to holes of varying geometries in GEM foils. Since the response of a GEM-based detector is closely related to the hole geometry through the influence of the latter on charge sharing and transport through GEM foils, attempts have been made to relate hole configurations to different figures of merit of a detector. Numerical simulations have been performed to study the effects of hole geometry on important parameters such as charge sharing, collection efficiency, extraction efficiency, gain, possibility of transition from avalanche to streamer modes for single-, double- and triple-layer GEM detectors. The numerical estimates have been compared to available experimental data. The comparisons, although not always in agreement, are found to be generally encouraging.

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Hamadi, Safi Allah, Aissa Chouder, Mohamed Mounir Rezaoui, Saad Motahhir et Ameur Miloud Kaddouri. « Improved Hybrid Parameters Extraction of a PV Module Using a Moth Flame Algorithm ». Electronics 10, n^o 22 (15 novembre 2021) : 2798. http://dx.doi.org/10.3390/electronics10222798.

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The identification of actual photovoltaic (PV) model parameters under real operating condition is a crucial step for PV engineering. An accurate and trusted model depends mainly on the accuracy of the model parameters. In this paper, an accurate and enhanced methodology is intended for PV module parameters extraction in outdoor conditions. The proposed methodology combines numerical methods and analytical formulations of the one diode model to derive the five unknown parameters in any operating condition of irradiance and temperature. First, the measured I-V curves at a random weather condition are translated to standard test conditions (i.e., G = 1000 W/m2, T = 25 °C), using translation equations. The second step consists of using an optimization algorithm namely the moth flame algorithm (MFO) to find out the five parameters at standard test conditions. Analytical formulations, at a random irradiance and temperature, are then used to express the unknown parameters at any irradiance and temperature. The proposed approach is validated under outdoor conditions against measured I-V curves at different irradiances and temperatures. The validation has also been performed under dynamic operation where the measured maximum power point coordinates (MPP) are compared to the predicted maximum power points. The obtained results from the adopted hybrid methodology confirm the accuracy of the parameter extraction procedure.

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Gallo, Monica, Andrea Formato, Martina Ciaravolo, Gaetano Formato et Daniele Naviglio. « Study of the Kinetics of Extraction Process for The Production of Hemp Inflorescences Extracts by Means of Conventional Maceration (CM) and Rapid Solid-Liquid Dynamic Extraction (RSLDE) ». Separations 7, n^o 2 (30 mars 2020) : 20. http://dx.doi.org/10.3390/separations7020020.

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In the present work, the kinetics of the extraction process from female inflorescences of Canapa sativa subsp. sativa var. sativa were studied, on the basis of determination of the content of cannabinoids: cannabidiolic acid (CBDA), Δ9-tetrahydrocannabinolic acid (THCA), cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC), before and after decarboxylation in the oven, in order to evaluate the possible use of the hemp extract obtained in the food sector. Therefore, both conventional maceration (CM) and rapid solid-liquid dynamic extraction (RSLDE), also known as cyclically pressurized extraction (CPE), were carried out, using parts of the plant approximately of the same size. The alcoholic extracts thus obtained were analyzed by high-performance liquid chromatography (HPLC) in order to calculate the percentages of cannabinoids present in the inflorescences and thus be able to evaluate the degree of decarboxylation. Furthermore, the extracts were dried to calculate the percentage of solid material present in it, that was made mainly by cannabinoids. The amount of substance extracted from the inflorescences was about 10% (w/w), for both cases considered. Therefore, the extraction yield was the same in the two cases examined and the final qualities were almost identical. However, the extraction times were significantly different. In fact, the maceration of hemp inflorescences in ethyl alcohol was completed in no less than 24 h, while with the RSLDE the extraction was completed in only 4 h. Finally, for a better understanding of the extraction process with cyclically pressurized extraction, a numerical simulation was carried out which allowed to better evaluate the influence of extractive parameters.

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Sabadus, Andreea, et Marius Paulescu. « On the Nature of the One-Diode Solar Cell Model Parameters ». Energies 14, n^o 13 (2 juillet 2021) : 3974. http://dx.doi.org/10.3390/en14133974.

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The one-diode model is probably the most common equivalent electrical circuit of a real crystalline solar cell. Extensive research has focused on extracting model parameters from measurements performed in standard test conditions (STC), aiming to replicate the current-voltage characteristics (I-V). This study started from finding that, for the same solar cell, different scientific reports yield significantly different sets of parameters, all allowing for highly accurate replication of the measured I-V characteristics. This observation raises a big question: What is the true physical set of parameters? The present study attempts to address this question. For this purpose, a numerical experiment was conducted. The results show that there is an infinity of distinct sets of parameters that can replicate the I-V characteristics at STC via the one-diode model equation. The diode saturation current IS and the diode ideality factor compensate each other to preserve the open-circuit voltage VOC, always an input data point. Some possible approaches (e.g., the link between VOC and IS) that can lead to the physical set of parameters are discussed, highlighting their strengths and weaknesses. There is enough room for future research on finding a universal approach able to guarantee the accurate extraction of the one-diode model physical parameters.

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