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Records with Keyword: Simulation
Showing records 1 to 25 of 32. [First] Page: 1 2 Last
Simulation of Ion Exchange Resin with Finite Difference Methods
Yawen Zhu, Bobo Liu, Ruichao Peng, Yunbai Luo, Ping Yu
December 9, 2019 (v1)
Keywords: finite difference method, ion exchange, Matlab, Simulation
Ion exchange resin is used to remove potentially corrosive impurities from coolant in the first circuit of a nuclear power plant. After one operational cycle, the used and unused resin in the mixed bed is discarded as solid waste. The aim of this work is to create a mathematical model to predict the operational cycle time of the mixed bed resin for reducing unused resin discharge. A partial differential equation (PDE) was set up with the conservation of matter. A finite difference method was used to solve the PDE. Matlab was the programming and calculating tool used in this work. The data from solution were obtained at different time and space nodes. The model was then verified experimentally using different ions on exchange columns. Concentrations of K+, Mn2+, and Cl- were calculated to verify the validation of the model by comparing it with experimental data. The calculated values showed good consistency with the experimental value.
Process Cost Management of Alzheimer’s Disease
Hana Tomaskova, Martin Kopecky, Petra Maresova
November 24, 2019 (v1)
Keywords: Alzheimer’s disease, BPMN, process cost management, Simulation, system dynamics
Summary: Determining the cost of healthcare and social care for patients is a crucial issue for many parties; therefore, both public and private payments play a decisive role in patient care. The article deals with the analysis of the possibilities of the simulation of costs related to Alzheimer’s disease. This disease is highly variable, and the cost items vary considerably. Therefore, it is necessary to use simulation methods. The results of simulation models can then be implemented in sophisticated methods working with activity costs. Findings: Models for health and social care are specific. No significant re-engineering is expected in this area, so the models must be unambiguous and easy to understand for all representatives involved. Modeling of business processes is thus a suitable means for analysis in this area. The process cost calculation is built on two simulation models. The first model is the Business Process Model and Notation (BPMN), the results of which are verified in... [more]
Experimental and Numerical Study of Double-Pipe Evaporators Designed for CO2 Transcritical Systems
Junlan Yang, Shuying Ning
November 5, 2019 (v1)
Keywords: Carbon Dioxide, double-pipe evaporator, experimental study, heat transfer, Simulation
The performance of a CO2 double-pipe evaporator was studied through experiments and a simulation model that was established by the steady-state distribution parameter method and experimentally verified while using a CO2 transcritical water‒water heat pump system. The effects of different operating parameters on heat transfer performance were studied over a range of evaporation temperatures (−5 to 5 °C), mass velocity (100‒600 kg/m2s), and heat flux (5000‒15,000 W/m2). It was found that the dryout quality increased at a small evaporation temperature, a large mass velocity, and a small heat flux. The simulation yield means relative error (RE) of heat transfer for the evaporation temperature and that of the CO2 pressure drop for the chilled water inlet temperature were 5.21% and 3.78%, respectively. The effect of tube diameter on the performance of CO2 double-pipe evaporator is probed through simulations. At the same time, this paper defines a parameter α , which is the proportio... [more]
Special Issue: Modeling and Simulation of Energy Systems
Thomas A. Adams
October 26, 2019 (v1)
Keywords: Energy, energy systems, Modelling, operations, Optimization, process design, process systems engineering, Simulation
This editorial provides a brief overview of the Special Issue “Modeling and Simulation of Energy Systems.” This Special Issue contains 21 research articles describing some of the latest advances in energy systems engineering that use modeling and simulation as a key part of the problem-solving methodology. Although the specific computer tools and software chosen for the job are quite variable, the overall objectives are the same—mathematical models of energy systems are used to describe real phenomena and answer important questions that, due to the hugeness or complexity of the systems of interest, cannot be answered experimentally on the lab bench. The topics explored relate to the conceptual process design of new energy systems and energy networks, the design and operation of controllers for improved energy systems performance or safety, and finding optimal operating strategies for complex systems given highly variable and dynamic environments. Application areas include electric powe... [more]
Distinct and Quantitative Validation Method for Predictive Process Modeling with Examples of Liquid-Liquid Extraction Processes of Complex Feed Mixtures
Axel Schmidt, Jochen Strube
July 31, 2019 (v1)
Keywords: atpe, biologics, design-of-experiments, liquid-liquid extraction, Modelling, monte-carlo, quality-by-design, Simulation, validation, verification
As of today, industrial process development for liquid-liquid extraction and scale-up of extraction columns is based on an experimental procedure that requires tests in pilot-scale. This methodology consumes large amounts of material and time and the utilized scale-up equations are crude estimates including considerable safety margins. This approach is practical for well-known systems or low-value products coupled with high production scale, where such a scale-up methodology has less impact on the overall profitability. However, for new high-value products in biologics manufacturing, a process development based on process understanding and the use of validated process models is imperative. Therefore, a distinct and quantitative validation workflow for liquid-liquid extraction modeling is presented on the example of two complex feed mixtures. Monte-Carlo simulations based on the presented model parameter determination concept result for both examples in prediction accuracy comparable to... [more]
Modernizing the Undergraduate Process Design Curriculum
Thomas Alan Adams II
July 20, 2019 (v1)
Subject: Education
Keywords: Curriculum, Education, Modelling, Process Design, Process Synthesis, Simulation
In this talk, I give an overview of the chemical engineering curriculum at McMaster University as it relates to the 1.5 year process design sequence. The courses outside the design sequence were recently restructured and redesigned to create an environment with more modelling and algorithmic thinking/algorithmic problem solving. This includes a statistics course and a big data / machine learning course. The end result is that the design sequence is able to focus on state of the art tools and methods for process design because students receive many fundamental principles before the design sequence begins.
Analysis of Influencing Factors of Occupational Safety and Health in Coal Chemical Enterprises Based on the Analytic Network Process and System Dynamics
Kai Yu, Lujie Zhou, Chen Hu, Linlin Wang, Weiqiang Jin
April 15, 2019 (v1)
Subject: Energy Policy
Keywords: analytic network process, management and control measures, occupational safety and health, Simulation, system dynamics
In the production process of coal chemical enterprises, there are factors such as dust, poisons, as well as toxic and harmful gases, which seriously restrict the safety and health of employees. It is urgent to strengthen research on occupational safety and health (OSH) of coal chemical enterprises. Research on the influencing factors is very important to improve the level of OSH in coal chemical enterprises. Therefore, this paper analyzed the factors affecting OSH of coal chemical enterprises from four aspects: “human⁻machine⁻environment⁻management„. Then, an influencing factor indicator system was constructed. The weights of the indicator were analyzed using the Analytic Network Process (ANP). On this basis, the primary and secondary indicators of the influencing factors were ranked. Subsequently, the weights of ANP were taken as the influence coefficient between variables, and the System Dynamics (SD) model of OSH control measures was established and analyzed. According to the weight... [more]
Simulation and Test Bed of a Low-Power Digital Excitation System for Industry 4.0
Jun-Ho Huh, Hoon-Gi Lee
April 8, 2019 (v1)
Keywords: computer architecture, digital excitation system, Industry 4.0, low power, operating system, Simulation, smart grid, Test Bed
Since modeling and simulation are the two most effective tools that can be used in the design or analysis process, they play a vital role in developing such system. In many cases, they are the only possible means of making a safe engineering decision for a new concept of process for a large-scale system. Elsewhere, they are used as a critical element in the analysis of energy systems or to suggest a method of developing a novel and effective energy system model. Thus, in this study, simulations and test bed experiment were carried out to assess a low-power digital excitation system in order to validate its effectiveness. The excitation systems currently used by most of the power stations in the Republic of Korea were installed during the 1970s or 1980s. Unfortunately, it is difficult to seek technical assistance for them as they depend on foreign technologies, requiring a large sum to be paid when requesting one or more engineers to be dispatched. As such, technical updates have always... [more]
Cold Storage for a Single-Family House in Italy
Luigi Mongibello, Giorgio Graditi
February 27, 2019 (v1)
Keywords: cold storage, cold water, economic analysis, PCM, Simulation, single-family house
This work deals with the operation, modeling, simulation, and cost evaluation of two different cold storage systems for a single-family house in Italy, that differ from one another on the cold storage material. The two materials used to perform the numerical simulations of the cold storage systems are represented by cold water and a phase change material (PCM), and the numerical simulations have been realized by means of numerical codes written in Matlab environment. The main finding of the present work is represented by the fact that, for the considered user characteristics, and under the Italian electricity tariff policy, the use of a proper designed cold storage system characterized by an effective operation strategy could represent a viable solution from an economical point of view.
Three-Dimensional Finite-Element Analysis of the Short-Time and Peak Withstand Current Tests in Substation Connectors
Francesca Capelli, Jordi-Roger Riba, Joan Pérez
November 28, 2018 (v1)
Keywords: connector, finite element method, peak withstand current test, short-time withstand current test, Simulation, substation
Power devices intended for high-voltage systems must be tested according to international standards, which includes the short-time withstand current test and peak withstand current test. However, these tests require very special facilities which consume huge amounts of electrical power. Therefore, mathematical tools to simulate such tests are highly appealing since they allow reproducing the electromagnetic and thermal behavior of the test object in a fast and economical manner. In this paper, a three-dimensional finite element method (3D-FEM) approach to simulate the transient thermal behavior of substation connectors is presented and validated against experimental data. To this end, a multiphysics 3D-FEM method is proposed, which considers both the connector and the reference power conductors. The transient and steady-state temperature profiles of both the conductors and connector provided by the 3D-FEM method prove its suitability and accuracy as compared to experimental data provid... [more]
Shielding Effectiveness Simulation of Small Perforated Shielding Enclosures Using FEM
Zdeněk Kubík, Jiří Skála
November 27, 2018 (v1)
Keywords: electromagnetic compatibility (EMC), finite element method (FEM), measurement, shielding effectiveness (SE), shielding enclosure, Simulation
Numerical simulation of shielding effectiveness (SE) of a perforated shielding enclosure is carried out, using the finite element method (FEM). Possibilities of model definitions and differences between 2D and 3D models are discussed. An important part of any simulation is verification of the model results—here the simulation result are verified in terms of convergence of the model in dependence on the degrees of freedom (DOF) and by measurements. The experimental method is based on measurement of electric field inside the enclosure using an electric field probe with small dimensions is described in the paper. Solution of an illustrative example of SE by FEM is shown and simulation results are verified by experiments.
Progress of Space Charge Research on Oil-Paper Insulation Using Pulsed Electroacoustic Techniques
Chao Tang, Bo Huang, Miao Hao, Zhiqiang Xu, Jian Hao, George Chen
October 23, 2018 (v1)
Keywords: insulation oil, insulation paper, moisture content, pulsed electroacoustic technique (PEA), Simulation, space charge, temperature
This paper focuses on the space charge behavior in oil-paper insulation systems used in power transformers. It begins with the importance of understanding the space charge behavior in oil-paper insulation systems, followed by the introduction of the pulsed electrostatic technique (PEA). After that, the research progress on the space charge behavior of oil-paper insulation during the recent twenty years is critically reviewed. Some important aspects such as the environmental conditions and the acoustic wave recovery need to be addressed to acquire more accurate space charge measurement results. Some breakthroughs on the space charge behavior of oil-paper insulation materials by the research team at the University of Southampton are presented. Finally, future work on space charge measurement of oil-paper insulation materials is proposed.
Maintenance Factor Identification in Outdoor Lighting Installations Using Simulation and Optimization Techniques
Ana Ogando-Martínez, Javier López-Gómez, Lara Febrero-Garrido
September 21, 2018 (v1)
Keywords: artificial lighting, calibration, GenOpt, radiance, Simulation, street light points
This document addresses the development of a novel methodology to identify the actual maintenance factor of the luminaires of an outdoor lighting installation in order to assess their lighting performance. The method is based on the combined use of Radiance, a free and open-source tool, for the modeling and simulation of lighting scenes, and GenOpt, a generic optimization program, for the calibration of the model. The application of this methodology allows the quantification of the deterioration of the road lighting system and the identification of luminaires that show irregularities in their operation. Values lower than 9% for the error confirm that this research can contribute to the management of street lighting by assessing real road conditions.
Internet of Energy Approach for Sustainable Use of Electric Vehicles as Energy Storage of Prosumer Buildings
Evgeny Nefedov, Seppo Sierla, Valeriy Vyatkin
September 21, 2018 (v1)
Keywords: distributed energy storage, electric vehicles, internet of energy, photovoltaic generation, prosumer, Simulation, smartgrid, vehicle-to-building, vehicle-to-grid
Vehicle-to-building (V2B) technology permits bypassing the power grid in order to supply power to a building from electric vehicle (EV) batteries in the parking lot. This paper investigates the hypothesis stating that the increasing number of EVs on our roads can be also beneficial for making buildings sustainably greener on account of using V2B technology in conjunction with local photovoltaic (PV) generation. It is assumed that there is no local battery storage other than EVs and that the EV batteries are fully available for driving, so that the EVs batteries must be at the intended state of charge at the departure time announced by the EV driver. Our goal is to exploit the potential of the EV batteries capacity as much as possible in order to permit a large area of solar panels, so that even on sunny days all PV power can be used to supply the building needs or the EV charging at the parking lot. A system architecture and collaboration protocols that account for uncertainties in EV... [more]
SOLIS—A Novel Decision Support Tool for the Assessment of Solar Radiation in ArcGIS
Jan K. Kazak, Małgorzata Świąder
September 21, 2018 (v1)
Keywords: ArcGIS, decision support system, photovoltaics, Renewable Energy, Simulation, solar radiation, sustainable development
The global Sustainable Development Goals influence the implementation of energy development strategies worldwide. However, in order to support local stakeholders in sustainable energy development strategies and climate change adaptation plans and the implementation of policies, there is a need to equip local decision makers with tools enabling the assessment of sustainable energy investments. In order to do so, the aim of this study is to create a novel tool for the assessment of solar radiation (SOLIS) in ArcGIS. The SOLIS tool builds on the existing ArcGIS algorithm by including input data conversion and post-processing of the results. This should expand the group of potential users of solar radiation analyses. The self-filtering tool excludes surfaces that are not suitable for solar energy investments due to geometrical reasons. The reduction of the size of the output data is positive for technical reasons (speed of the calculation and occupied storage place) and for cognitive reaso... [more]
Identification of the Heat Equation Parameters for Estimation of a Bare Overhead Conductor’s Temperature by the Differential Evolution Algorithm
Mirza Sarajlić, Jože Pihler, Nermin Sarajlić, Gorazd Štumberger
September 21, 2018 (v1)
Keywords: conductor temperature, measurement, Optimization, overhead transmission line, parameter identification, Simulation
This paper deals with the Differential Evolution (DE) based method for identification of the heat equation parameters applied for the estimation of a bare overhead conductor`s temperature. The parameters are determined in the optimization process using a dynamic model of the conductor; the measured environmental temperature, solar radiation and wind velocity; the current and temperature measured on the tested overhead conductor; and the DE, which is applied as the optimization tool. The main task of the DE is to minimise the difference between the measured and model-calculated conductor temperatures. The conductor model is relevant and suitable for the prediction of the conductor temperature, as the agreement between measured and model-calculated conductor temperatures is exceptional, where the deviation between mean and maximum measured and model-calculated conductor temperatures is less than 0.03 °C.
Design, Construction, and Testing of a Gasifier-Specific Solid Oxide Fuel Cell System
Alvaro Fernandes, Joerg Brabandt, Oliver Posdziech, Ali Saadabadi, Mayra Recalde, Liyuan Fan, Eva O. Promes, Ming Liu, Theo Woudstra, Purushothaman Vellayan Aravind
September 21, 2018 (v1)
Keywords: Exergy, Simulation, SOFC, Syngas, validation
This paper describes the steps involved in the design, construction, and testing of a gasifier-specific solid oxide fuel cell (SOFC) system. The design choices are based on reported thermodynamic simulation results for the entire gasifier- gas cleanup-SOFC system. The constructed SOFC system is tested and the measured parameters are compared with those given by a system simulation. Furthermore, a detailed exergy analysis is performed to determine the components responsible for poor efficiency. It is concluded that the SOFC system demonstrates reasonable agreement with the simulated results. Furthermore, based on the exergy results, the components causing major irreversible performance losses are identified.
Efficiency Improvement of a Natural Gas Marine Engine Using a Hybrid Turbocharger
Marco Altosole, Giovanni Benvenuto, Ugo Campora, Federico Silvestro, Giulio Terlizzi
September 19, 2018 (v1)
Keywords: hybrid turbocharger, natural gas marine engine, Simulation
The use of a computer simulator, previously developed and validated, applied to a four-stroke marine dual-fuel engine, has allowed the authors to present in this paper a solution to improve the overall efficiency of the engine by adopting a hybrid turbocharger. This component replaces the original one allowing, in addition to maintaining the previous usual functions, the production of electricity to satisfy part of the ship’s electric load. In this study the application of the hybrid turbocharger concerns an engine powered by natural gas in particular. The turbocharger substitution involves a significant variation of the engine load governor operating mode. The improved engine characteristics that the hybrid turbocharger facilitates, compared to the original, are highlighted by the results reported in tabular and graphical form, for different engine loads and speeds.
Modelling and Simulation of Biochemical Processes Using Petri Nets
Safae Cherdal, Salma Mouline
August 28, 2018 (v1)
Subject: Biosystems
Keywords: biochemical processes, diseases, HFPN, metabolic pathway, Methionine cycle, Petri nets, Simulation
Systems composed of many components which interact with each other and lead to unpredictable global behaviour, are considered as complex systems. In a biological context, complex systems represent living systems composed of a large number of interacting elements. In order to study these systems, a precise mathematical modelling was typically used in this context. However, this modelling has limitations in the structural understanding and the behavioural study. In this sense, formal computational modelling is an approach that allows to model and to simulate dynamical properties of these particular systems. In this paper, we use Hybrid Functional Petri Net (HFPN), a Petri net extension dedicated to study and verify biopathways, to model and study the Methionine metabolic pathway. Methionine and its derivatives play significant roles in human bodies. We propose a set of simulations for the purpose of studying and analysing the Methionine pathway’s behaviour. Our simulation results have sh... [more]
Modelling of a Naphtha Recovery Unit (NRU) with Implications for Process Optimization
Jiawei Du, William R. Cluett
July 31, 2018 (v1)
Keywords: naphtha recovery unit, Optimization, Simulation, statistical model
The naphtha recovery unit (NRU) is an integral part of the processes used in the oil sands industry for bitumen extraction. The principle role of the NRU is to recover naphtha from the tailings for reuse in this process. This process is energy-intensive, and environmental guidelines for naphtha recovery must be met. Steady-state models for the NRU system are developed in this paper using two different approaches. The first approach is a statistical, data-based modelling approach where linear regression models have been developed using Minitab® from plant data collected during a performance test. The second approach involves the development of a first-principles model in Aspen Plus® based on the NRU process flow diagram. A novel refinement to this latter model, called “withdraw and remix„, is proposed based on comparing actual plant data to model predictions around the two units used to separate water and naphtha. The models developed in this paper suggest some interesting ideas for the... [more]
Systematic Design and Evaluation of an Extraction Process for Traditionally Used Herbal Medicine on the Example of Hawthorn (Crataegus monogyna JACQ.)
Maximilian Sixt, Jochen Strube
July 31, 2018 (v1)
Keywords: harvest, Modelling, pressurized hot water extraction, Simulation, variety
Traditionally used herbal medicines are deep in the consciousness of patients for the treatment of only minor diseases by self-medication. However, manufacturers of herbal medicinal products suffer from major problems such as increasing market pressure by e.g., the food supplement sector, increasing regulations, and costs of production. Moreover, due to more stringent regulation and approval processes, innovation is hardly observed, and the methods used in process development are outdated. Therefore, this study aims to provide an approach based on modern process engineering concepts and including predictive process modelling and simulation for the extraction of traditional herbal medicines as complex extracts. The commonly used solvent-based percolation is critically assessed and compared to the so-called pressurized hot water extraction (PHWE) as a new possible alternative to replace organic solvents. In the study a systematic process design for the extraction of hawthorn (Crataegus m... [more]
Modelling Condensation and Simulation for Wheat Germ Drying in Fluidized Bed Dryer
Der-Sheng Chan, Jun-Sheng Chan, Meng-I Kuo
July 31, 2018 (v1)
Keywords: condensation, fluidized bed drying, mathematical model, moisture content, Simulation, wheat germ
A low-temperature drying with fluidized bed dryer (FBD) for wheat germ (WG) stabilization could prevent the loss of nutrients during processing. However, both evaporation and condensation behaviors occurred in sequence during FBD drying of WG. The objective of this study was to develop a theoretical thin-layer model coupling with the macro-heat transfer model and the bubble model for simulating both the dehydration and condensation behaviors of WG during low-temperature drying in the FBD. The experimental data were also collected for the model modification. Changes in the moisture content of WG, the air temperature of FBD chamber, and the temperature of WG during drying with different heating approaches were significantly different. The thermal input of WG drying with short heating time approach was one-third of that of WG drying with a traditional heating approach. The mathematical model developed in this study could predict the changes of the moisture content of WG and provide a good... [more]
The Spectrum of Mechanism-Oriented Models and Methods for Explanations of Biological Phenomena
C. Anthony Hunt, Ahmet Erdemir, William W. Lytton, Feilim Mac Gabhann, Edward A. Sander, Mark K. Transtrum, Lealem Mulugeta
July 31, 2018 (v1)
Keywords: computational model, explanatory model, hybrid model, mechanism, mechanistic model, modeling methods, provenance, Simulation, systems modeling, workflow
Developing and improving mechanism-oriented computational models to better explain biological phenomena is a dynamic and expanding frontier. As the complexity of targeted phenomena has increased, so too has the diversity in methods and terminologies, often at the expense of clarity, which can make reproduction challenging, even problematic. To encourage improved semantic and methodological clarity, we describe the spectrum of Mechanism-oriented Models being used to develop explanations of biological phenomena. We cluster explanations of phenomena into three broad groups. We then expand them into seven workflow-related model types having distinguishable features. We name each type and illustrate with examples drawn from the literature. These model types may contribute to the foundation of an ontology of mechanism-based biomedical simulation research. We show that the different model types manifest and exert their scientific usefulness by enhancing and extending different forms and degre... [more]
Using Simulation for Scheduling and Rescheduling of Batch Processes
Girish Joglekar
July 31, 2018 (v1)
Keywords: Batch Process, coordination control, rescheduling, Scheduling, Simulation
The problem of scheduling multiproduct and multipurpose batch processes has been studied for more than 30 years using math programming and heuristics. In most formulations, the manufacturing recipes are represented by simplified models using state task network (STN) or resource task network (RTN), transfers of materials are assumed to be instantaneous, constraints due to shared utilities are often ignored, and scheduling horizons are kept small due to the limits on the problem size that can be handled by the solvers. These limitations often result in schedules that are not actionable. A simulation model, on the other hand, can represent a manufacturing recipe to the smallest level of detail. In addition, a simulator can provide a variety of built-in capabilities that model the assignment decisions, coordination logic and plant operation rules. The simulation based schedules are more realistic, verifiable, easy to adapt for changing plant conditions and can be generated in a short perio... [more]
Systematic and Model-Assisted Evaluation of Solvent Based- or Pressurized Hot Water Extraction for the Extraction of Artemisinin from Artemisia annua L.
Maximilian Sixt, Jochen Strube
July 31, 2018 (v1)
Keywords: artemisinin, Extraction, Green Solvents, Modelling, Pressurized Hot Water Extraction, Simulation
In this study, the solvent based extraction of artemisinin from Artemisia annua L. using acetone in percolation mode is compared to the method of pressurized hot water extraction. Both techniques are simulated by a physico-chemical process model. The model as well as the model parameter determination, including the thermal degradation of artemisinin are shown and discussed. For the conventional extraction, a solvent screening is performed considering various organic solvents. A temperature screening is presented for the systematic design of the pressurized hot water extraction. The best temperature with regards to thermal decomposition and high productivity was found to be 80 °C. Both, conventional percolation and Pressurized Hot Water Extraction (PHWE) are suitable for the extraction of artemisinin. The extraction curves show a high conformity with the simulation results.
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