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A bearing‐vehicle‐track coupling dynamic model is built in this paper and the validity of the model is proved by comparing the simulation data with the theoretical data. Based on this model, the influence of wheel diameter difference (WDD) on the dynamic behavior of wheelset bearing is studied. The results demonstrate that when the bogie has a rear WDD, lateral displacement (LaD) of the front wheelset is the smallest. When the bogie has an anti‐phase WDD, LaD of the rear wheelset is the smallest, while when the bogie has an in‐phase WDD, LaD of the front and rear wheelsets is the largest, and LaD of the front and rear WDD is between the two, which is in line with the theoretical analysis results. Compared with LaD results of the wheelset bearing outer raceway under normal conditions, when the wheel has a diameter difference, LaD distance of the outer race increases with the WDD increasing, and the frequency of lateral movement also increases with the increase against the WDD gradation. The high‐frequency and large‐distance lateral movement of the wheelset bearing outer race under the WDD will increase the roller‐outer raceway force, and accelerate the failure of the bearing. [ABSTRACT FROM AUTHOR]

A biogas plant is fed with agricultural substrates at an average organic loading rate of 6 kgVS per m3 fermenter volume per day and substrates with relatively high nitrogen content. This situation results in a below‐average methane yield, so the aim is to increase the substrate efficiency. An analysis of the actual condition of the plant was performed and compared with reference values. A dynamic simulation model of the biogas plant was created and adjusted with data over an operating year. The model adjustment provided a good approximation of the simulation results to the key operating variables and thus allows the evaluation of different operating variations. The effect of various measures was analyzed by simulation and it showed a potential increase in substrate efficiency of up to 15 %. [ABSTRACT FROM AUTHOR]

Sustainable wildlife trade is critical for biodiversity conservation, livelihoods, and food security. Regulatory frameworks are needed to secure these diverse benefits of sustainable wildlife trade. However, regulations limiting trade can backfire, sparking illegal trade if demand is not met by legal trade alone. Assessing how regulations affect wildlife market participants' incentives is key to controlling illegal trade. Although much research has assessed how incentives at both the harvester and consumer ends of markets are affected by regulations, little has been done to understand the incentives of traders (i.e., intermediaries). We built a dynamic simulation model to support reduction in illegal wildlife trade within legal markets by focusing on incentives traders face to trade legal or illegal products. We used an Approximate Bayesian Computation approach to infer illegal trading dynamics and parameters that might be unknown (e.g., price of illegal products). We showcased the utility of the approach with a small‐scale fishery case study in Chile, where we disentangled within‐year dynamics of legal and illegal trading and found that the majority (∼77%) of traded fish is illegal. We utilized the model to assess the effect of policy interventions to improve the fishery's sustainability and explore the trade‐offs between ecological, economic, and social goals. Scenario simulations showed that even significant increases (over 200%) in parameters proxying for policy interventions enabled only moderate improvements in ecological and social sustainability of the fishery at substantial economic cost. These results expose how unbalanced trader incentives are toward trading illegal over legal products in this fishery. Our model provides a novel tool for promoting sustainable wildlife trade in data‐limited settings, which explicitly considers traders as critical players in wildlife markets. Sustainable wildlife trade requires incentivizing legal over illegal wildlife trade and consideration of the social, ecological, and economic impacts of interventions. Article impact statement: Simulation models that explicitly consider traders' roles in wildlife markets can help support reduction in illegal wildlife trade. [ABSTRACT FROM AUTHOR]

Intersecting orthogonal strike‐slip faults with opposite senses of slip pose the question of what allows rupture to propagate through the junction and through both faults versus confining rupture to a single fault. I conduct dynamic rupture simulations on simplified orthogonal strike‐slip fault systems, to determine which conditions produce rupture on both component faults. In models with uniform initial tractions on both faults, slip on the first fault must reduce normal stress on the second fault for it to rupture. If the first fault ends at the cross fault, a stopping phase causes the cross fault to rupture. In models where I resolve a uniform regional stress field on the faults, only a narrow range of stress orientations allow multifault ruptures. These results will be helpful for evaluating hazard near orthogonal strike‐slip faults. Plain Language Summary: There are many examples around the world where two strike‐slip earthquake faults cross each other at nearly 90° angles. This is not remarkable when only one of the faults in a pair causes an earthquake, but it becomes notable when two or more crossing faults move at the same time. This raises the question of what causes the second fault to get involved, or not. To address this question, I use computer simulations of the physics of the earthquake process to test dozens of different fault configurations and earthquake starting points. I find that the location where the earthquake starts on the first fault controls whether the second fault is made stronger versus weaker, and therefore whether both faults can move together in one earthquake. These results can help us understand earthquake hazard around crossing faults. Key Points: Nucleation location effectively controls whether multifault rupture occurs on orthogonal strike‐slip fault systemsA stopping phase from rupture reaching the end of one fault is often required to initiate rupture on the cross faultOnly a narrow range of regional stress orientations allows both cross‐faults to rupture [ABSTRACT FROM AUTHOR]

Several observations and simulations suggested that the supershear rupture induced by free surface invariably occurs in strike‐slip faults rather than in dip‐slip faults. To explore the mechanism of supershear transition induced by free surface on oblique faults, we simulate spontaneous dynamic rupture propagation governed by slip‐weakening friction on nonvertical planar faults. We find that oblique thrust faults are more likely to produce free‐surface‐induced supershear transition than oblique normal faults and significant asymmetry arises between the two opposite directions along fault strike. The supershear rupture may only occur within shallow depth or over the entire seismogenic depth, depending on geometric relations between the slip and rupture propagation vectors. Our results help explain the lack of universal observation of supershear earthquakes. Besides, the asymmetric ground shaking on the oblique faults allows us to predict the possible spatial distribution of the high seismic risk. Plain Language Summary: Flat free surface tends to induce supershear transition provided there exists a long enough propagation distance. Previous studies suggested that this transition invariably occurs in strike‐slip faults rather than in dip‐slip faults. We use numerical simulation to investigate the mechanism of supershear transition induced by free surface on oblique faults, which have comparable strike‐slip and dip‐slip components. We find that oblique thrust faults are more likely to produce supershear transition with the changes in style of faulting from dominated dip slip to dominated strike slip. Moreover, significant asymmetry arises between the two opposite directions along fault strike. The supershear rupture may only occur within shallow depth or over the entire fault depth, depending on geometric relations between the slip and rupture propagation vectors. Our results help explain the lack of universal observation of supershear earthquakes. Besides, the distribution of peak ground velocity derived from dynamic modeling indicates that the asymmetric ground shaking on the oblique faults significantly depends on dip angle and slip rake angle, which allows us to predict the possible spatial distribution of the high seismic risk. Key Points: Oblique thrust faults are more likely to generate free‐surface‐induced supershear transition than oblique normal onesThe asymmetric ground shaking on the oblique faults allows us to predict the possible spatial distribution of the high seismic riskThe asymmetry of the supershear transition is due to the different geometric relations between the slip and rupture propagation vectors [ABSTRACT FROM AUTHOR]

The focus of this paper is the development of fast solvable dynamic mathematical models (real‐time models). Real‐time models represent a part of model‐based tools that can be used to prevent and eliminate emergency situations in industry. In this paper, the development of real‐time models is illustrated for chemical absorption, using rigorous dynamic rate‐based models. An approach to develop the real‐time models is explained in detail and the outcome is presented in the form of mathematical equation systems. The results are shown for the chemical absorption of CO2 by aqueous monoethanolamine solutions. [ABSTRACT FROM AUTHOR]

Failure scenarios of process plants are examined in safety talks. Dynamic simulations can be employed to make non‐linear dynamic interactions transparent over the boundaries of individual process units and therefore gain importance in the support of safety analyses. They are useful to investigate the effectiveness of countermeasures, contribute to the design of tailor‐made shutdown systems and help to avoid over‐conservative designs. The validity of fluid dynamic models implemented in model‐libraries needs to be ascertained. Adaptions may be required here. [ABSTRACT FROM AUTHOR]

A comprehensive computational fluid dynamic (CFD) model of CEES‐developed polyethylenimine impregnated protonated titanate nanotubes (PEI‐PTNTs) was developed using the Multiphase Flow with Interphase eXchanges (MFiX) package to evaluate the performance of the PEI‐PTNTs in a 1‐MW pilot‐scale carbon capture reactor developed by the National Energy Technology Laboratory (NETL). In this CFD model, the momentum, continuity, and energy transport equations were integrated with the first‐order chemistry model for chemical kinetics of heterogeneous reactions to predict the adsorption of CO2 onto amine‐based sorbent particles and the reactor temperature. Based on the amount of the CO2 adsorption obtained in the small‐scale experiment, the coefficients for the chemical reaction equations of PEI‐PTNTs are adjusted. The adjusted PEI‐PTNTs model is applied to the simplified numerical model of 1‐MW pilot‐scale carbon capture system, which is calibrated through the comparison between our simulation results and the results provided by NETL. This calibrated CFD model is used for selecting the optimized flow rate of the gas phase. Our study shows that the optimized gas flow rate to absorb 100% CO2 without loss is 1.5 kg/s, but if higher absorption rate is preferable despite some loss of CO2 absorption in the reactor, a higher flow rate than 1.5 kg/s can be selected. [ABSTRACT FROM AUTHOR]

The largest earthquakes of the 2019 Ridgecrest, California, sequence were a M6.4 left‐lateral rupture followed 34 hr later by a M7.1 on a perpendicular right‐lateral fault. We use dynamic rupture modeling to address the questions of why the first earthquake did not propagate through the right‐lateral fault in one larger event, whether stress changes from the M6.4 were necessary for the M7.1 to occur, and how the Ridgecrest earthquakes affected the nearby Garlock Fault. We find that dynamic clamping and shear stress reduction confined surface rupture in the M6.4 to the left‐lateral fault. We also find that stress changes from the M6.4 were not necessary to allow a M7.1 on the right‐lateral fault but that they affected the slip and likely accelerated the timing of the M7.1. Lastly, we find that the Ridgecrest earthquakes may have brought the central Garlock Fault closer to failure. Plain Language Summary: The M6.4 and M7.1 Ridgecrest, California, earthquakes of July 2019 occurred 34 hr apart, on two faults that cross each other. We used physics‐based computer simulations of the earthquake process to investigate why both faults did not move together in one bigger earthquake and whether the second earthquake only happened due to effects from the first. We found that the fault movement in the first earthquake compressed the second fault, which prevented it from moving at the same time. We also found that the second fault could have had a M7.1 earthquake on its own, without the influence of the M6.4 on the previous day but that the first earthquake affected the details of the second and likely made the second one happen sooner than it would have otherwise. This has meaning both for understanding why the Ridgecrest earthquakes happened this way and also for understanding possible earthquake behaviors on other crossing faults. We also looked at whether the Ridgecrest earthquakes brought the nearby Garlock Fault, which is capable of a M8 earthquake, closer to having a big earthquake, and we found that this is possible but not certain. Key Points: Dynamic stress changes from the first Ridgecrest earthquake were insufficient to immediately trigger the second earthquakeAlthough the first earthquake did not create the conditions necessary for the second to occur, it affected the slip distribution and timingStress changes from the Ridgecrest ruptures explain the location of creep on the Garlock Fault and may have brought it closer to failure [ABSTRACT FROM AUTHOR]

Stress drop characterizing dynamics of earthquake rupture propagation has various definitions and measures with a yet unclear mutual relationship. We aim to reconcile this discrepancy by analyzing synthetic dynamic rupture models generated by random sampling of the model space of spatially heterogeneous dynamic rupture parameters. An ensemble of ~1,600 dynamic models, with waveforms statistically fitting empirical Ground Motion Prediction Equations, is treated as a synthetic event database. The events exhibit various magnitudes, degrees of complexity, and realistic ω−2 spectral decay of their average moment rates. While the variability of the stress drop Δτe estimated from the moment rates agrees with real data studies (σlnΔτe~1.1), the true static stress drops Δτs evaluated directly from the dynamic models exhibit larger values and lower variability (σlnΔτs~0.4). Our study suggests that the disagreement between various stress drop definitions is related to the source model approximation and not to any particular data processing. Plain Language Summary: During an earthquake, the stress accumulated on a fault suddenly releases. Earthquake stress drop is thus a significant parameter characterizing the dynamics of rupture propagation. However, its definition and its inference from observed data is ambiguous and inferred stress drops vary among researchers both in terms of values and variability. Here we have reconciled this discrepancy by inspecting synthetic physics‐based dynamic rupture models, which provide parameters that are difficult to assess in reality, in particular, the stress change before and after the earthquake. We randomly generate synthetic events that are compatible with observed strong ground motions from a large number of real earthquakes. The events exhibit various magnitudes and degrees of complexity. We explore various stress drop measures estimated following seismological practice and true stress drop evaluated directly from the dynamic models. While the estimated stress drops agree with empirical findings, the true stress drop exhibits larger values and lower variability. Our study suggests that the discrepancy between the various stress drops is related to the too simplistic assumptions on the source model used in empirical studies. The individual rupture process of each event is more complex and, therefore, not entirely captured by a single stress drop parameter. Key Points: We generate and analyze large database of synthetic dynamic rupture events compatible with empirical Ground Motion Prediction EquationsWe reconcile discrepancy between various stress drop measures obtained from seismological analyses and true stress drop on faultThe ambiguity arises from Brune source model assumption, suitable for average source properties but oversimplifying individual ruptures [ABSTRACT FROM AUTHOR]

This study investigates a multi-status simulation method based on event-driven for a smart distribution network (SDN). By switching a steady simulation model and a dynamic simulation model, the typical events of the SDN with various time constants can be simulated within the same simulation framework. The aim of the proposed method is to make full utilisation of the advantages of conventional simulation methods when considering the actual operation process of the SDN with many typical events so that the simulation results can approach the actual situation. To ensure that the operating status and corresponding simulation models of the SDN could be switched correctly and automatically, a simulation engine is proposed and implemented based on a finite state machine. Multi-status simulation experiments on IEEE 33-bus and an actual 10-kV distribution network validate the proposed multi-status simulation method. [ABSTRACT FROM AUTHOR]

This study explains the underlying concepts and implementation details of using an open source distribution analysis tool – OpenDSS to conduct dynamic simulations of converter interfaced generation (CIG) in large, realistic power distribution systems. The dynamic models of different types of CIGs are derived and written into the dynamic‐link library (DLL) to be called by OpenDSS during simulation. The DLL development is illustrated in detail with the programme structure and the model derivation of CIG. A phasor domain modelling method is adopted to derive single‐phase CIG models in order to make the DLL models compatible with OpenDSS. The conversion between phasor and natural waveform data when simulating single‐phase systems is discussed. The DLLs are derived based on the equations of the power stage circuit including the filters and the specific controllers. Applications of developed DLLs are illustrated with test cases, where volt‐VAR control and microgrid mode control of CIGs are tested in a large‐scale distribution system. This study can be used as a tutorial for performing the dynamic analysis for single‐phase converters in OpenDSS. [ABSTRACT FROM AUTHOR]

The present paper tackles a problem in the candidate reactions literature: the replicability of results that emerge when using in vivo and in vitro designs. The current study was designed to provide a conceptual replication of a dynamic model of change in fairness perceptions during the hiring process, using a different research design, different measures, and a different sample than the original paper. A sample of 209 participants in a simulated selection process reported their level of perceived fairness three times: before the testing, after the testing, and after the results were communicated. These results support the results of the original that the construction of fairness perceptions declines in a nonlinear way over time, with high initial levels of fairness perception corresponding to a lower rate of decline, and vice versa. Further analysis revealed no change in the individuals' conceptualization of perceived fairness nor any shift in the respondents' use of the measurement scale (i.e., no beta and gamma change were detected). [ABSTRACT FROM AUTHOR]

ABSTRACT The dynamic process behavior of Engineering Design Processes (EDPs) needs to be understood in order to distribute resources appropriately as well as for cost and schedule calculation. Currently, structural and behavioral modeling approaches are used in the context of EDP management. In many use cases, it is essential to have at hand both the static structural view and the dynamic behavioral one. Currently, however, the two modeling approaches cannot be sufficiently combined. Within this work, a framework for the structure-based System Dynamics analysis of EDPs is presented. It uses structural models as a basis for constructing System Dynamics models to simulate the process behavior and thereby supports understanding the correlation of process structure and behavior. This framework was iteratively developed by conducting case studies and consists of three layers, a five-step procedure and special support for the transformation of the models. For the validation, a subset of the design process at a large German commercial vehicle manufacturer has been chosen. Based on the application of the framework during a six-month project at the company, the industrial experts rated the framework as beneficial for the purpose of optimizing EDPs. Furthermore, they stated that the transparent representation of the sequence of the process, influencing factors and control variables in combination with the quantitative data had improved their understanding of the overall process. [ABSTRACT FROM AUTHOR]

This study presents the modelling and dynamic simulation of a high penetration wind diesel power system (WDPS) consisting of a diesel generator (DG), a wind turbine generator (WTG), consumer load, dump load and a battery energy storage system (BESS). First the WDPS architecture and the models of the WDPS components are described. The WDPS is simulated in wind-only (WO) mode where the DG is not running and the WTG supply active power and in wind-diesel (WD) mode where both DG and WTG supply power. The simulation results are given showing graphs of the main electric variables in the WDPS (system frequency and voltage and active power in each component) and main battery variables (current, voltage and state of charge). The results in the WO mode show how the BESS, under the command of a proportional-integral-derivative (PID) controller, supplies/stores active power to regulate the isolated system frequency. The WD control enables the BESS to smooth the load and wind power variations, so that the isolated system power quality is improved. Also it is shown in the WD mode a peak shaving application where the control orders the BESS to supply active power temporarily to support system frequency in a DG overload situation. [ABSTRACT FROM AUTHOR]

Based on the actual situation of the knowledge flow during industrial transfer, a dynamic model of knowledge flow in a complex network is built. The mechanism of the knowledge flow in the network is analysed, and an analogue simulation is conducted using the Netlogo platform to identify the effects of the network's average degree, the number of enterprises involved in the transfer, the network size, and the effective transmission rate of the knowledge on the efficiency of the knowledge flow in the network. According to the final steady state of the knowledge, the technology spillover effect of the industrial transfer is then discussed. The research results show that the average degree of the network, the number of enterprises involved in the transfer, and the effective transmission rate of the knowledge have significant influences on the efficiency of the knowledge flow in the network, and increasing the network size is beneficial to increasing the number of final knowledge owners. Thus, the final steady state of the knowledge flow plays a decisive role in the technology spillover effect of industrial transfer. [ABSTRACT FROM AUTHOR]