simulation process
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2022 ◽  
Vol 12 (2) ◽  
pp. 549
Author(s):  
Łukasz Gierz ◽  
Ewelina Kolankowska ◽  
Piotr Markowski ◽  
Krzysztof Koszela

This article presents the results of research on the influence of moisture on changes in the physical properties, i.e., the length, width, thickness, and weight, of dressed and untreated cereal seeds in order to improve the simulation process based on the discrete element method (DEM). The research was conducted on the seeds of three winter cereals, i.e., triticale, rye, and barley. The seeds with an initial moisture content of about 7% were moistened to five levels, ranging from 9.5% to 17.5%, at an increment of 2%. The statistical analysis showed that moisture significantly influenced the physical properties of the seeds, i.e., their length, width, thickness, and weight. As the moisture content of the seeds increased, there were greater differences in their weight. The average increase in the thousand kernel weight resulting from the increase in their moisture content ranged from 4 to 6 mg. The change in the seed moisture content from 9.5% to 17.5% significantly increased the volume of rye seeds from 3.10% to 14.99%, the volume of triticale seeds from 1.00% to 13.40%, and the volume of barley seeds from 1.00% to 15.33%. These data can be used as a parameter to improve the DEM simulation process.


2021 ◽  
Author(s):  
Wenjun Cai ◽  
Jia Liu ◽  
Xueping Zhu ◽  
Xuehua Zhao

Abstract Hydrological climate-impact projections in future are limited by large uncertainties from various sources. Therefore, this study aimed to explore and estimate the sources of uncertainties involved in climate changing impacted assessment in a representative watershed of Northeastern China. Moreover, recent researches indicated that the climate internal variability (CIV) plays an important role in various of hydrological climate-impact projections. Six downscaled Global climate models (GCMs) under two emission scenarios and a calibrate Soil and Water Assessment Tool (SWAT) model were used to obtain hydrological projections in future periods. The CIV and signal-to-noise ratio (SNR) are investigated to analyze the the role of internal variability in hydrological projections. The results shows that the internal variability shows a considerable influence on hydrological projections, which need be partitioned and quantified particularly. Moreover, it worth noting the CIV can propagate from precipitation and ET to runoff projections through the hydrological simulation process. In order to partition the CIV and sources of uncertainties, the uncertainty decomposed frameworks based on analysis of variance (ANOVA) are established. The results demonstrate that the CIV and GCMs are the dominate contributors of runoff in rainy season. In contrast, the CIV and SWAT model parameter sets provided obvious uncertainty to runoff in January to May and October to December. The findings of this study advised that the uncertainty is complex in hydrological simulation process hence, it is meaning and necessary to estimate the uncertainty in climate simulation process, the uncertainty analysis results can provide effectively efforts to reduce uncertainty and then give some positive suggestions to stakeholders for adaption countermeasure under climate change.


Aerospace ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 9
Author(s):  
Michel Nöding ◽  
Martin Schuermann ◽  
Lothar Bertsch ◽  
Marc Koch ◽  
Martin Plohr ◽  
...  

The German Aerospace Center has launched an internal project to assess the noise impact associated with supersonic transport aircraft during approach and departure. A dedicated simulation process is established to cover all relevant disciplines, i.e., aircraft and engine design, engine installation effects, flight simulation, and system noise prediction. The core of the simulation process is comprised of methods at the complexity and fidelity level of conceptual aircraft design, i.e., typical overall aircraft design methods and a semi-empirical approach for the noise modeling. Dedicated interfaces allow to process data from high fidelity simulation that will support or even replace initial low fidelity results in the long run. All of the results shown and discussed in this study are limited to the fidelity level of conceptual design. The application of the simulation process to the NASA 55t Supersonic Technology Concept Aeroplane, i.e., based on non-proprietary data for this vehicle, yields similar noise level predictions when compared to the published NASA results. This is used as an initial feasibility check of the new process and confirms the underlying methods and models. Such an initial verification of the process is understood as an essential step due to the lack of available noise data for supersonic transport aircraft in general. The advantageous effect of engine noise shielding on the resulting system noise is demonstrated based on predicted level time histories and certification noise levels. After this initial verification, the process is applied to evaluate a conceptual supersonic transport design based on a PhD thesis with two engines mounted under the wing, which is referred to as aircraft TWO. Full access to this vehicle’s design and performance data allows to investigate the influence of flight procedures on the resulting noise impact along approach and departure. These noise results are then assembled according to proposed Federal Aviation Agency regulations in their Notice of Proposed Rulemaking, e.g., speed limitations, for Supersonic transport noise certification and the regulations from Noise Chapters of the Annex 16 from the International Civil Aviation Organization in order to evaluate the resulting levels as a function of the flight procedure.


Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4371
Author(s):  
Dorin-Ioan Catana ◽  
Mihai-Alin Pop ◽  
Denisa-Iulia Brus

Additive manufacturing is one of the technologies that is beginning to be used in new fields of parts production, but it is also a technology that is constantly evolving, due to the advances made by researchers and printing equipment. The paper presents how, by using the simulation process, the geometry of the 3D printed structures from PLA and PLA-Glass was optimized at the bending stress. The optimization aimed to reduce the consumption of filament (material) simultaneously with an increase in the bending resistance. In addition, this paper demonstrates that the simulation process can only be applied with good results to 3D printed structures when their mechanical properties are known. The inconsistency of printing process parameters makes the 3D printed structures not homogeneous and, consequently, the occurrence of errors between the test results and those of simulations become natural and acceptable. The mechanical properties depend on the values of the printing process parameters and the printing equipment because, in the case of 3D printing, it is necessary for each combination of parameters to determine their mechanical properties through specific tests.


Author(s):  
Mikhail A. Belostotsky ◽  
Anatoly M. Korolenok

The author presents the methodology for identifying risks in operation of main oil pipelines, which can be based upon in improvement of methods for planning overhauls of the main pipelines. A method for calculating reliability indicators of the system is reviewed, including analysis of the type distributions of the system elements failures pattern. The reliability of the system is determined by purely mathematical operations on the obtained distributions. Such an approach is typical for the system (structural, mathematical) theory of reliability, the key task thereof being the transition from the elements reliability indicators to the system reliability indicators. It is advisable to resolve the problems of calculating the actual reliability of a complex technical system taking for consideration the dependencies of its elements, based on the approach assuming that reliability of the elements and the system shall be calculated in the general multi-level simulation process wherein both physical and structural models are used. Physical models of elements reliability are used at lower levels, while structural models are used at higher ones. Установлена своевременность и актуальность идентификации и формализации структурно-логических связей показателей эксплуатации линейной части магистральных нефтепроводов. Представлена методология идентификации рисков при эксплуатации магистральных нефтепроводов, которая может быть положена в основу совершенствования методов планирования их капитальных ремонтов. Рассмотрен метод для расчета показателей надежности технической системы, предусматривающий анализ типовых распределений отказов ее элементов. Надежность системы находится чисто математическими операциями над полученными распределениями. Подобный подход характерен для системной (структурной, математической) теории надежности, основной задачей которой является переход от показателей надежности элементов к показателям надежности системы. Задачи расчета реальной надежности сложной технической системы с учетом зависимостей ее элементов целесообразно решать на основе подхода, который состоит в том, что расчет надежности элементов и системы проводится в общем многоуровневом имитационном моделирующем процессе с применением физических и структурных моделей. Физические модели надежности элементов используются на низших уровнях, а структурные модели – на высших.


2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Shijun Guo ◽  
Shubham Sharma ◽  
Alibek Issakhov ◽  
Nima Khalilpoor

Aim. Epichlorohydrin (ECH) is a widely used chemical product. The production of glycerol has its irreplaceable advantages. With the development of biodiesel industry, it will become the main trend of ECH production in the future. Methods. A vacuum evaporation device is built to investigate the effect of evaporation on the treatment of this kind of high-salt wastewater, and the feasibility of the thermodynamic equation of the simulation process is verified. Process. An AHR fuzzy mathematics evaluation algorithm is used to compare experimental values with simulated numerical values in brine. Results and Conclusions. In the multieffect evaporation process simulation with glycerin-containing brine, the amount of salt precipitated by unit steam energy is arranged in order from more to less than that of seven-effect parallel flow evaporation, is greater than five-effect parallel flow evaporation, and is larger than three-effect parallel flow evaporation, which shows that the increase of validity number is beneficial to the utilization of heat.


2021 ◽  
Vol 9 (4B) ◽  
Author(s):  
Hüseyin Y. DALKILIÇ ◽  
◽  
Amin GHAREHBAGHI ◽  

This paper documents a novel numerical model for calculating the behavior of unsteady, one-dimensional groundwater flow by using the finite volume method. The developed model determined water table fluctuations for different scenarios as follows: Drainage and recession from an unconfined aquifer, and water table fluctuations above an inclined leaky layer due to ditch recharge with a constant and variable upper boundary condition. The Boussinesq equation, which is the governing equation in this domain, is linearized and solved numerically in both of the explicit and fully implicit conditions. Meanwhile, the upwind scheme is employed to discretize the governing equation. The computed outcomes of both the explicit and implicit approaches agreed well with the results of analytical solution and laboratory experiments. The main reason is that in the first half of simulation process explicit scheme obtains slightly better results and in the second half of the simulation process fully implicit scheme predicts more reliable outcomes that are hidden in the neighbor node points. As a final point, the numerical outcomes confirm that the developed model is capable of calculating satisfactory outcomes in engineering and science applications.


2021 ◽  
Vol 28 (4) ◽  
pp. 142-150
Author(s):  
Mirosław Łącki

Abstract This study presents a method for the dynamic value assignment of evolutionary parameters to accelerate, automate and generalise the neuroevolutionary method of ship handling for different navigational tasks and in different environmental conditions. The island model of population is used in the modified neuroevolutionary method to achieve this goal. Three different navigational situations are considered in the simulation, namely, passing through restricted waters, crossing with another vessel and overtaking in the open sea. The results of the simulation examples show that the island model performs better than a single non-divided population and may accelerate some complex and dynamic navigational tasks. This adaptive island-based neuroevolutionary system used for the COLREG manoeuvres and for the finding safe ship’s route to a given destination in restricted waters increases the accuracy and flexibility of the simulation process. The time statistics show that the time of simulation of island NEAT was shortened by 6.8% to 27.1% in comparison to modified NEAT method.


2021 ◽  
Author(s):  
Jingjing Hu ◽  
Weipeng Hu ◽  
Fan Zhang ◽  
Han Zhang ◽  
Zichen Deng

Abstract The existence of the Gaussian solitary wave solution in the logarithmic-KdV equation has aroused considerable interests recently. Focusing on the defects of the reported multi-symplectic analysis on the Gaussian solitary wave solution of the logarithmic-KdV equation and considering the dynamic symmetry breaking of the logarithmic-KdV equation, new approximate multi-symplectic formulations for the logarithmic-KdV equation are deduced and the associated structure-preserving scheme is constructed to simulate the evolution of the Gaussian solitary wave solution. In the structure-preserving simulation process of the Gaussian solitary wave solution, the residuals of three conservation laws are recorded in each step. Comparing with the reported numerical results, it can be found that the Gaussian solitary wave solution can be simulated with tiny numerical errors and three conservation laws are preserved perfectly in the simulation process by the structure-preserving scheme presented in this paper, which implies that the proposed structure-preserving scheme improved the precision as well as the structure-preserving properties of the reported multi-symplectic approach.


2021 ◽  
Vol 15 ◽  
pp. 17-24
Author(s):  
Amelia Bucur ◽  
Jose L. Lopez-Bonilla

The aim of the present paper is to approach the matter of water quality by resorting to the metod of multicriterial mathematical programming. MicrosoftExcel enables the simulation of a mathematical model. Furthermore, we have also created a file in the C++ software, in view of the simulation process, applicable to numberless properties of water quality. The case study presents the simulation of a multicriterial analysis of water quality in Sibiu county. This particular study shows the means of obtaining more information about water quality, subsequent to the analysis of its characteristics resorting to statistical analysis-specific software, e.g. SPSS 16 software. Given the increase of drinking water worldwide by tens of percentage points in cca two decades, the author(s) consider(s) that an approach to the quality management of drinking water should represent a key priority of society.


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