Detailed simulation of storage hydropower systems in large Alpine watersheds

An activated sludge model for biological N- and P-removal was developed, which describes anoxic and aerobic P-uptake based on bacterial metabolism. This model was tested in practice on two wastewater treatment plants, which are BCFS®-processes, which contain activated sludge with a high fraction of denitrifying P-removing bacteria (DPB's). The model appeared to be able to give an adequate description of the performance of these treatment plants under different conditions. If the process parameters are well defined almost no calibration of the biokinetic parameters was necessary. In the simulation of Dalfsen wwtp, which has a complex control scheme, it was possible to give an adequate simulation of the control actions and the concentration profiles in a rather simple way, showing that detailed simulation of these controllers was not necessary. With the calibrated model it was possible to analyse bottlenecks and give suggestions for upgrading of the concerned treatments plants. The simulation results were used in decisions on investments.

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A simulation study of excitation contour of a linear trap with spatial harmonics

European Journal of Mass Spectrometry ◽

10.1177/14690667211020153 ◽

2021 ◽

pp. 146906672110201

Author(s):

NV Konenkov

Keyword(s):

Ion Trap ◽

Theoretical Description ◽

Resonance Peak ◽

Linear Ion Trap ◽

Linear Trap ◽

Ion Fragmentation ◽

Excitation Time ◽

Detailed Simulation ◽

Trajectory Method ◽

Ion Cloud

The process of nonlinear resonant excitation of ion oscillations in a linear trap is studied. There is still no detailed simulation of the resonance peak in the literature. We propose to use the excitation contour to describe the collective ion resonance. The excitation contour is a resonant mass peak obtained by the trajectory method with the Gaussian distribution of the initial coordinates and velocities. The following factors are considered: excitation time, low order hexapole and octopole harmonics with amplitudes A3 and A4, the depth of the initial ion cloud position. These multipoles are used for selective ion ejection from linear ion trap. All these factors affect the ion yield and the shape of the contours. Obtained data can be useful for control of such processes as ion fragmentation, ion isolation, ion activation, and ion ejection. Simulated resonance peaks are important for the theoretical description of the ion collective nonlinear resonances.

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The Influence of Operating Strategies regarding an Energy Optimized Driving Style for Electrically Driven Railway Vehicles

Energies ◽

10.3390/en14030583 ◽

2021 ◽

Vol 14 (3) ◽

pp. 583

Author(s):

Lukas Pröhl ◽

Harald Aschemann ◽

Roberto Palacin

Keyword(s):

Load Distribution ◽

Optimization Approach ◽

Total Energy Consumption ◽

Driving Style ◽

Optimal Velocity ◽

Railway Vehicles ◽

Operating Modes ◽

Detailed Simulation ◽

Operating Strategies ◽

Optimal Driving

The aim of this paper is the optimization of velocity trajectories for electrical railway vehicles with the focus on total energy consumption. On the basis of four fundamental operating modes—acceleration, cruising, coasting, and braking—energy-optimal trajectories are determined by optimizing the sequence of the operating modes as well as the corresponding switching points. The optimization approach is carried out in two consecutive steps. The first step ensures compliance with the given timetable, regarding both time and position constraints. In the second step, the influence of different operating strategies, such as load distribution and the switch-off of traction components during low loads, are analyzed to investigate the characteristics of the energy-optimal velocity trajectory. A detailed simulation model has been developed to carry out the analysis, including an assessment of its capabilities and advantages. The results suggest that the application of load-distribution techniques, either by a switch-off of parallel traction units or by a load-distribution between active units, can affect the energy-optimal driving style.

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Scalable Multiport Converter Structure for Easy Grid Integration of Alternate Energy Sources for Generation of Isolated Voltage Sources for MMC

Electronics ◽

10.3390/electronics10151779 ◽

2021 ◽

Vol 10 (15) ◽

pp. 1779

Author(s):

Syed Rahman ◽

Irfan Khan ◽

Khaliqur Rahman ◽

Sattam Al Otaibi ◽

Hend I. Alkhammash ◽

...

Keyword(s):

Renewable Energy ◽

Renewable Energy Sources ◽

Energy Resources ◽

Energy Sources ◽

Renewable Energy Resources ◽

Component Level ◽

Storage Devices ◽

Multiport Converter ◽

Detailed Simulation ◽

The Individual

This paper presents a novel, scalable, and modular multiport power electronic topology for the integration of multiple resources. This converter is not only scalable in terms of the integration of multiple renewable energy resources (RES) and storage devices (SDs) but is also scalable in terms of output ports. Multiple dc outputs of a converter are designed to serve as input to the stacking modules (SMs) of the modular multilevel converter (MMC). The proposed multiport converter is bidirectional in nature and superior in terms of functionality in a way that a modular universal converter is responsible for the integration of multiple RES/SDs and regulates multiple dc output ports for SMs of MMC. All input ports can be easily integrated (and controlled), and output ports also can be controlled independently in response to any load variations. An isolated active half-bridge converter with multiple secondaries acts as a central hub for power processing with multiple renewable energy resources that are integrated at the primary side. To verify the proposed converter, a detailed design of the converter-based system is presented along with the proposed control algorithm for managing power on the individual component level. Additionally, different modes of power management (emulating the availability/variability of renewable energy sources (RES)) are exhibited and analyzed here. Finally, detailed simulation results are presented in detail for the validation of the proposed concepts and design process.

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One-IPC high-level simulation of microthreaded many-core architectures

The International Journal of High Performance Computing Applications ◽

10.1177/1094342015584495 ◽

2016 ◽

Vol 31 (2) ◽

pp. 152-162 ◽

Cited By ~ 3

Author(s):

Irfan Uddin

Keyword(s):

Design Space Exploration ◽

Instruction Set ◽

Efficient Design ◽

Simulation Framework ◽

Fine Grained ◽

Detailed Simulation ◽

High Level ◽

Many Core ◽

The Cost ◽

Multiple Clusters

The microthreaded many-core architecture is comprised of multiple clusters of fine-grained multi-threaded cores. The management of concurrency is supported in the instruction set architecture of the cores and the computational work in application is asynchronously delegated to different clusters of cores, where the cluster is allocated dynamically. Computer architects are always interested in analyzing the complex interaction amongst the dynamically allocated resources. Generally a detailed simulation with a cycle-accurate simulation of the execution time is used. However, the cycle-accurate simulator for the microthreaded architecture executes at the rate of 100,000 instructions per second, divided over the number of simulated cores. This means that the evaluation of a complex application executing on a contemporary multi-core machine can be very slow. To perform efficient design space exploration we present a co-simulation environment, where the detailed execution of instructions in the pipeline of microthreaded cores and the interactions amongst the hardware components are abstracted. We present the evaluation of the high-level simulation framework against the cycle-accurate simulation framework. The results show that the high-level simulator is faster and less complicated than the cycle-accurate simulator but with the cost of losing accuracy.

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Iterative stability analysis for general polynomial control systems

Nonlinear Dynamics ◽

10.1007/s11071-021-06768-7 ◽

2021 ◽

Author(s):

Bo Xiao ◽

Hak-Keung Lam ◽

Zhixiong Zhong

Keyword(s):

Stability Analysis ◽

Lyapunov Function ◽

Control Systems ◽

Polynomial System ◽

Stability Conditions ◽

General Polynomial ◽

Main Challenge ◽

Detailed Simulation ◽

Feasible Solutions ◽

The Stability

AbstractThe main challenge of the stability analysis for general polynomial control systems is that non-convex terms exist in the stability conditions, which hinders solving the stability conditions numerically. Most approaches in the literature impose constraints on the Lyapunov function candidates or the non-convex related terms to circumvent this problem. Motivated by this difficulty, in this paper, we confront the non-convex problem directly and present an iterative stability analysis to address the long-standing problem in general polynomial control systems. Different from the existing methods, no constraints are imposed on the polynomial Lyapunov function candidates. Therefore, the limitations on the Lyapunov function candidate and non-convex terms are eliminated from the proposed analysis, which makes the proposed method more general than the state-of-the-art. In the proposed approach, the stability for the general polynomial model is analyzed and the original non-convex stability conditions are developed. To solve the non-convex stability conditions through the sum-of-squares programming, the iterative stability analysis is presented. The feasible solutions are verified by the original non-convex stability conditions to guarantee the asymptotic stability of the general polynomial system. The detailed simulation example is provided to verify the effectiveness of the proposed approach. The simulation results show that the proposed approach is more capable to find feasible solutions for the general polynomial control systems when compared with the existing ones.

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Comparison of Crash Test and Simulation Results for Impact of Silverado Pickup into New Jersey Barrier under Manual for assessing Safety Hardware

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/2309-12 ◽

2012 ◽

Vol 2309 (1) ◽

pp. 114-126 ◽

Cited By ~ 4

Author(s):

Dhafer Marzougui ◽

Cing-Dao (Steve) Kan ◽

Kenneth S. Opiela

Keyword(s):

New Jersey ◽

Primary Objective ◽

Crash Test ◽

Fe Model ◽

George Washington ◽

Statistical Measures ◽

Detailed Simulation ◽

Analysis Center ◽

Simulation Results ◽

Concrete Barrier

The National Crash Analysis Center (NCAC) at the George Washington University simulated the crash of a 2,270-kg Chevrolet Silverado pickup truck into a standard 32-in. New Jersey shape concrete barrier under the requirements of Test 3–11 of the Manual for Assessing Safety Hardware (MASH). The new, detailed finite element (FE) model for the Chevrolet Silverado was used as the surrogate for the MASH 2270P test vehicle. An FE model of the New Jersey barrier was drawn from the array of NCAC hardware models. The primary objective of this analysis was to simulate the crash test conducted to evaluate how this commonly used, NCHRP 350–approved device would perform under the more rigorous MASH crashworthiness criteria. A secondary objective was to use newly developed verification and validation (V&V) procedures to compare the results of the detailed simulation with the results of crash tests undertaken as part of another project. The crash simulation was successfully executed with the detailed Silverado FE model and NCAC models of the New Jersey concrete barrier. Traditional comparisons of the simulation results and the data derived from the crash test suggested that the modeling provided viable results. Further comparisons employing the V&V procedures provided a structured assessment across multiple factors reflected in the phenomena importance ranking table. Statistical measures of the accuracy of the test in comparison with simulation results provided a more robust validation than previous approaches. These comparisons further confirmed that the model was able to replicate impacts with a 2270P vehicle, as required by MASH.

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Hider: A Methodology for Early-Stage Exploration of Design Space

Volume 3: 22nd Design Automation Conference ◽

10.1115/96-detc/dac-1089 ◽

1996 ◽

Author(s):

Sudhakar Y. Reddy

Keyword(s):

Design Space ◽

Optimization Problems ◽

Early Stage ◽

Simulation Models ◽

Design Tool ◽

System Level ◽

Complex Simulation ◽

Machine Learning Approach ◽

Detailed Simulation ◽

And Performance

Abstract This paper describes HIDER, a methodology that enables detailed simulation models to be used during the early stages of system design. HIDER uses a machine learning approach to form abstract models from the detailed models. The abstract models are used for multiple-objective optimization to obtain sets of non-dominated designs. The tradeoffs between design and performance attributes in the non-dominated sets are used to interactively refine the design space. A prototype design tool has been developed to assist the designer in easily forming abstract models, flexibly defining optimization problems, and interactively exploring and refining the design space. To demonstrate the practical applicability of this approach, the paper presents results from the application of HIDER to the system-level design of a wheel loader. In this demonstration, complex simulation models for cycle time evaluation and stability analysis are used together for early-stage exploration of design space.

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