On Ways to Use Normalized Euler Parameters as Kinematic State Variables in Dynamic Simulation

Author(s):  
R. E. Roberson
2014 ◽  
Vol 941-944 ◽  
pp. 2336-2340
Author(s):  
Gong Xi Wang ◽  
Wei Jia Zhao

A challenging problem in the numerical simulation of a self-contacted elastic rod is the change of topological structure during the contacting process. In this article, a numerical approach is introduced to simulate a self-contacted Cosserat rod. By introducing the angular velocity and Euler parameters as the state variables, an improved Lagrange equation is introduced. A finite element method is built to deal with the simplified model, and numerical examples are given.


Author(s):  
Andrew Hahn ◽  
Timothy Schriener ◽  
Mohamed S. El-Genk

Abstract Enabling transmission of state variables and controller command signals between physics-based model and physical or emulated PLC requires developing fast and synchronous communication interface. This research investigates four methods of interface communication: (a) reading/writing to text files, (b) serial communication, (c) TCP communication, and (d) shared memory. The shared memory interfacing method provides the best performance, reliability, and fidelity. It is validated by linking a representative PLC controller to a Simulink dynamic simulation model of a fully integrated space reactor power system with multiple closed Brayton cycle loops for energy conversion (DynMo-CBC). Transient performance results of the PLC controlled dynamic simulation model are identical to those obtained using the Simulink model with internal control.


2021 ◽  
Vol 14 (4) ◽  
pp. 850
Author(s):  
Edna Guevara-Rivera ◽  
Roberto Osorno-Hinojosa ◽  
Victor Zaldivar-Carrillo ◽  
Humberto Perez-Ortiz

Purpose: Circular economy (CE) principles have evolved in response to natural resource depletion as a set of guidelines for eliminating the linear take-use-dispose model of product consumption. The consequences of shifting from a linear to a circular supply chain are difficult to visualize in the long term. This study aims to design a methodology for building a simulation model to implement CE strategies in any small and medium-sized enterprise SME to prove policies before implementing them in the real world. This paper applied the methodology in a biological cycle case study: a confectionery factory in Mexico.Design/methodology/approach: This study evaluated service-dominant logic, ecosystem services, system dynamics, and agent-based modeling to design the proposed methodology. A series of interviews with stakeholders were performed to assess the simulation model during the development phase. The circular economy indicator prototype (CEIP) was used as a circular maturity measure of the confectionery factory. The simulator was executed in Netlogo software, implementing a four-scenario analysis based on two CE policies for the caramel recycling process. Five state variables were proposed in this analysis: confectionery waste, recycled glucose, recycling utilization, costs of recycled glucose, and profit.Findings: The CEIP score of the confectionery factory was 52%, rated as a “good” product. Regarding scenario analysis, the first scenario had the highest profit improvement.Practical implications: The simulator allowed stakeholders to understand the operation of the recycling process and visualize all variables involved in the system.Originality/value: In the CE literature, little attention has been paid to proposing a methodology for designing a simulation model to implement CE strategies in any industry. Thus, this study implements a nine-step methodology based on services context and dynamic simulation tools to design a platform to evaluate and visualize the consequences of CE strategies implementation in the long term.


1993 ◽  
Vol 70 (06) ◽  
pp. 0998-1004 ◽  
Author(s):  
Páll T Önundarson ◽  
H Magnús Haraldsson ◽  
Lena Bergmann ◽  
Charles W Francis ◽  
Victor J Marder

SummaryThe relationship between lytic state variables and ex vivo clot lysability was investigated in blood drawn from patients during streptokinase administration for acute myocardial infarction. A lytic state was already evident after 5 min of treatment and after 20 min the plasminogen concentration had decreased to 24%, antiplasmin to 7% and fibrinogen 0.2 g/1. Lysis of radiolabeled retracted clots in the patient plasmas decreased from 37 ± 8% after 5 min to 21 ± 8% at 10 min and was significantly lower (8 ± 9%, p <0.005) in samples drawn at 20, 40 and 80 min. Clot lysability correlated positively with the plasminogen concentration (r = 0.78, p = 0.003), but not with plasmin activity. Suspension of radiolabeled clots in normal plasma pre-exposed to 250 U/ml two-chain urokinase for varying time to induce an in vitro lytic state was also associated with decreasing clot lysability in direct proportion with the duration of prior plasma exposure to urokinase. The decreased lysability correlated with the time-dependent reduction in plasminogen concentration (r = 0.88, p <0.0005). Thus, clot lysability decreases in conjunction with the development of the lytic state and the associated plasminogen depletion. The lytic state may therefore limit reperfusion during thrombolytic treatment.


1995 ◽  
Vol 115 (5) ◽  
pp. 479-486
Author(s):  
Naoki Kobayashi ◽  
Takeshi Yamada ◽  
Hiroshi Okamoto ◽  
Yasuyuki Tada ◽  
Atsushi Kurita ◽  
...  

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