Journal articles on the topic 'Inertia'
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1
Sun, Ning, Jin Wang, and Fang Hua Lei. "A New Method to Measure Inertial Parameters of Rigid Body Based on Energy Decay Theory." Advanced Materials Research 146-147 (October 2010): 151–55. http://dx.doi.org/10.4028/www.scientific.net/amr.146-147.151.
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Most measuring methods used now can only measure the rigid body’s six inertial parameters like the moment of inertia, the product of inertia and the centre of inertia toward to two-dimensional reference system. So a new method which can measure all the nine inertial parameters toward to three-dimensional reference system is proposed. The moment of inertia of object rotating the axis is obtained by energy decay method. Through using the translation and rotation transformation theory of product of inertia, the formula of moment of inertia including the information of product of inertia and centre of inertia is deduced. Then equations are built to solve all the parameters. Furthermore, a measuring instrument is designed based on the aerostatic bearing. Results show that this new method is available and by analyzing the experimental data, suggestions are made to improve this measuring method.
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Li, Zhiyong, Rui Cui, Li Li, Yingli Hu, and Ruwan Ranasinghe. "Inertia Stages and Tourists' Behavior." International Journal of Tourism and Hospitality Management in the Digital Age 2, no. 1 (January 2018): 1–17. http://dx.doi.org/10.4018/ijthmda.2018010101.
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This article integrates the concept of inertia into a tourism context to understand how repeat visitors act and make revisit decisions. Moderating effect of zone of tolerance (ZOT), switching barriers (SWI) and external opportunity (OPP) on the sequential development of inertial behavior was analyzed through 518 tourists. Findings confirm that cognitive inertia (COGI) and affective inertia (AFFI) are significantly and positively related to conative inertia (CONI), while conative inertia also has a direct effect on determining action inertia (ACTI). The tests of moderating effects of zone of tolerance, switching barriers and external opportunity on the sequential development of inertial behavior show these variables have a significant moderating effect on the sequential development of inertia, except for the relation between switching barriers and affective inertia acting together, and conative inertia. These findings provide valuable insights that enable one to understand tourists' revisit behaviors. Theoretical and empirical implications are discussed, for the purpose of advancing tourism marketing discourse.
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Riggs, Peter J. "Inertia and inertial resistance in the Special Theory of Relativity." Canadian Journal of Physics 99, no. 9 (September 2021): 795–98. http://dx.doi.org/10.1139/cjp-2021-0087.
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A broader concept of “resistance to acceleration” than used in classical dynamics, called “inertial resistance”, is quantified for both inertial and non-inertial relativistic motion. Special Relativity shows that inertial resistance is more than particle inertia and originates from Minkowski spacetime structure. Current mainstream explanations of inertia do not take inertial resistance into account and are, therefore, incomplete.
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Mujcinagic, Alija, Mirza Kusljugic, and Emir Nukic. "Wind Inertial Response Based on the Center of Inertia Frequency of a Control Area." Energies 13, no. 23 (November 24, 2020): 6177. http://dx.doi.org/10.3390/en13236177.
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As a result of the increased integration of power converter-connected variable speed wind generators (VSWG), which do not provide rotational inertia, concerns about the frequency stability of interconnected power systems permanently arise. If the inertia of a power system is insufficient, wind power plants’ participation in the inertial response should be required. A trendy solution for the frequency stability improvement in low inertia systems is based on utilizing so-called “synthetic” or “virtual” inertia from modern VSWG. This paper presents a control scheme for the virtual inertia response of wind power plants based on the center of inertia (COI) frequency of a control area. The PSS/E user written wind inertial controller based on COI frequency is developed using FORTRAN. The efficiency of the controller is tested and applied to the real interconnected power system of Southeast Europe. The performed simulations show certain conceptual advantages of the proposed controller in comparison to traditional schemes that use the local frequency to trigger the wind inertial response. The frequency response metrics, COI frequency calculation and graphical plots are obtained using Python.
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Thiesen, Henning. "Power System Inertia Dispatch Modelling in Future German Power Systems: A System Cost Evaluation." Applied Sciences 12, no. 16 (August 21, 2022): 8364. http://dx.doi.org/10.3390/app12168364.
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Increasing the share of grid frequency converter-connected renewables reduces power system inertia, which is crucial for grid frequency stability. However, this development is insufficiently covered by energy system modelling and analysis as well as related scientific literature. Additionally, only synchronous inertia from fossil fuel-emitting power plants is represented, although renewable generators are a source of synthetic inertia, thus resulting in increased must-run capacities, CO2 emissions and system costs. The work at hands adds an analysis of the future German power system considering sufficient inertia to the literature. Therefore, results of an novel open-source energy system model are analysed. The model depicts minimum system inertia constraints as well as wind turbines and battery storage systems as a carbon-dioxide-free source for a synthetic inertial response. Results indicate that integrating system inertia constraints in energy system models has a high impact on indicators such as system costs. Especially when investments in additional storage units providing an inertial response are necessary. With respect to researched scenarios, system cost increases range from 1% up to 23%. The incremental costs for providing additional inertia varies between 0.002 EURO/kg·m2 and 0.61 EURO/kg·m2.
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Li, Yang, Zhichuan Zhu, Alin Hou, Qingdong Zhao, Liwei Liu, and Lijuan Zhang. "Pulmonary Nodule Recognition Based on Multiple Kernel Learning Support Vector Machine-PSO." Computational and Mathematical Methods in Medicine 2018 (2018): 1–10. http://dx.doi.org/10.1155/2018/1461470.
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Pulmonary nodule recognition is the core module of lung CAD. The Support Vector Machine (SVM) algorithm has been widely used in pulmonary nodule recognition, and the algorithm of Multiple Kernel Learning Support Vector Machine (MKL-SVM) has achieved good results therein. Based on grid search, however, the MKL-SVM algorithm needs long optimization time in course of parameter optimization; also its identification accuracy depends on the fineness of grid. In the paper, swarm intelligence is introduced and the Particle Swarm Optimization (PSO) is combined with MKL-SVM algorithm to be MKL-SVM-PSO algorithm so as to realize global optimization of parameters rapidly. In order to obtain the global optimal solution, different inertia weights such as constant inertia weight, linear inertia weight, and nonlinear inertia weight are applied to pulmonary nodules recognition. The experimental results show that the model training time of the proposed MKL-SVM-PSO algorithm is only 1/7 of the training time of the MKL-SVM grid search algorithm, achieving better recognition effect. Moreover, Euclidean norm of normalized error vector is proposed to measure the proximity between the average fitness curve and the optimal fitness curve after convergence. Through statistical analysis of the average of 20 times operation results with different inertial weights, it can be seen that the dynamic inertial weight is superior to the constant inertia weight in the MKL-SVM-PSO algorithm. In the dynamic inertial weight algorithm, the parameter optimization time of nonlinear inertia weight is shorter; the average fitness value after convergence is much closer to the optimal fitness value, which is better than the linear inertial weight. Besides, a better nonlinear inertial weight is verified.
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Sun, Ling, Peng Yu, and Tong Zhang. "Measurement Method Research on Inertial Parameters of Motor Assembly." Applied Mechanics and Materials 437 (October 2013): 663–68. http://dx.doi.org/10.4028/www.scientific.net/amm.437.663.
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Inertial parameters of the motor assembly include its mass, CM (center of mass) position, moment of inertia and product of inertia. Taking one vehicle drive motor as the research object, its mass and CM position are measured by using weight method and moment balance method respectively. Its moment of inertia and product of inertia are measured by using three-wire pendulum. On the basis of analyzing the test error, this paper proposed specific measures to reduce the test error.
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Xu, Chenglong, Liang Cheng, and Huimin Qian. "Virtual Inertia Control of Wind Turbine Based on Model Predictive Control." Journal of Physics: Conference Series 2310, no. 1 (October 1, 2022): 012092. http://dx.doi.org/10.1088/1742-6596/2310/1/012092.
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Abstract A useful method for system frequency adjustment of wind turbines is theoretical inertia control. The classic PD theoretical inertia control has difficulty in parameter setting, and does not provide useful inertial support for the system on a case-by-case basis. Therefore, a theoretical inertia control way for wind turbines on account of Model Predictive Control (MPC) is proposed, which provides inertia support when frequency events occur. To confirm the availability of the proposed control method, MATLAB/Simulink® software was employed for system modeling and simulation. The simulation consequences demonstrate that when the system is disturbed by the load, the proposed MPC theoretical inertia control has better robustness and frequency stability than PD theoretical inertia control.
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Berg, C., and J. Rayner. "The moment of inertia of bird wings and the inertial power requirement for flapping flight." Journal of Experimental Biology 198, no. 8 (January 1, 1995): 1655–64. http://dx.doi.org/10.1242/jeb.198.8.1655.
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The agility and manoeuvrability of a flying animal and the inertial power required to flap the wings are related to the moment of inertia of the wings. The moments of inertia of the wings of 29 bird species and three bat species were determined using wing strip analysis. We also measured wing length, wing span, wing area, wing mass and body mass. A strong correlation (r2=0.997) was found between the moment of inertia and the product of wing mass and the square of wing length. Using this relationship, it was found that all birds that use their wings for underwater flight had a higher than average moment of inertia. Assuming sinusoidal wing movement, the inertial power requirement was found to be proportional to (body mass)0.799, an exponent close to literature values for both metabolic power output and minimum power required for flight. Ignoring wing retraction, a fairly approximate estimate showed that the inertial power required is 11­15 % of the minimum flight power. If the kinetic energy of the wings is partly converted into aerodynamic (useful) work at stroke reversal, the power loss due to inertial effects may be smaller.
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Martínez Aranda, Luis Manuel, and Rodrigo Fernández Gonzalo. "Comparación de dos dispositivos de medición de potencia y trabajo durante ejercicio de fuerza con tecnología inercial flywheel (Comparison of two power and work data acquisition systems during resistance exercise employing flywheel inertial technology)." Retos, no. 29 (December 18, 2015): 144–48. http://dx.doi.org/10.47197/retos.v0i29.41308.
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El objetivo del presente estudio fue comparar los valores de potencia y trabajo obtenidos en tiempo real mediante los sistemas BlueBrainTM y SmartCoachTM, durante ejercicio de fuerza en una prensa de piernas equipada con tecnología inercial flywheel, usando diferentes inercias (cargas). Se realizaron ocho series de siete repeticiones a intensidades variable y máxima, con dos minutos de descanso entre series, para cada inercia utilizada en el protocolo: 0.0125; 0.025; 0.0375; 0.05; 0.0625 y 0.075 kg*m², midiendo simultáneamente la potencia media concéntrica y el trabajo total (concéntrico-excéntrico) con ambos dispositivos. Los datos fueron analizados mediante un análisis de regresión lineal y un estudio de correlación. Se observó una correlación altamente significativa en los datos de potencia media entre ambos dispositivos en todas las inercias e intensidades evaluadas, tanto a nivel individual como global, (r=.968; Sig.(bilateral)=.000; R2=.937). De la misma forma, los datos de trabajo correlacionaron de forma muy significativa (r=.978; Sig.(bilateral)=.000; R2=.957). Las diferencias de registro entre ambos dispositivos oscilaron en un rango de 2.6-4.3 %. Dado el alto grado de significación en las correlaciones analizadas para potencia y trabajo, todo parece indicar que ambos dispositivos se muestran como instrumentos válidos y similares para estimar la potencia y el trabajo durante ejercicios de fuerza con tecnología inercial, siendo de gran ayuda para el seguimiento y control del entrenamiento usando esta tecnología.Abstract. The aim of this study was to compare real-time values of power and work obtained through BlueBrainTM and SmartCoachTM systems during flywheel leg press exercise using different inertias (loads). Eight sets of seven repetitions were performed at variable and maximum intensity for each inertia used (i.e. 0.0125; 0.025; 0.0375; 0.05; 0.0625 and 0.075 kg*m2), with 2 minutes recovery between sets. Average power during concentric actions and total work (concentric-eccentric) were measured simultaneously using both systems. Data were analysed using a linear regression analysis and correlation procedures. Strong significant correlations were observed in average power results between both data acquisition systems for all individual inertias and intensities evaluated, as well as for overall data (r=.968; Sig.(2-tailed)=.000; R2=.937). In addition, work values showed clear significant correlations (r=.978; Sig.(2-tailed)=.000; R2=.957). Differences between devices oscillated over a range of 2.6-4.3%. The strong correlations found in power and work values seem to indicate that both data acquisition systems are similar and valid to estimate power and work during resistance exercises employing flywheel inertial technology. Thus, both devices may represent a helpful tool to control and follow up training using flywheel technology.
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BOTIȘ, Marius, and Costel PLEȘCAN. "The Probabilistic Method for Determination the Inertia Characteristics of 3D Bodies with Monte Carlo Algorithms." Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science 45, no. 3 (September 15, 2022): 33–36. http://dx.doi.org/10.35219/mms.2022.3.07.
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This study determines the inertial characteristics of bodies with probabilistic algorithms of the Monte Carlo type. To determine the mechanical moments of inertia in the case of three-dimensional bodies, the bodies are decomposed into simple bodies for which the moments of inertia are calculated, which are added to Steiner's relations. If the bodies have complex shapes to determine the moments of mechanical inertia, numerical or probabilistic algorithms can be used. This paper presents the main stages in the use of probabilistic algorithms for calculating moments of inertia and finally a program in MATLAB that allows determining the moments of inertia for bodies.
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Kushwaha, Prabhakar, Sanjoy K. Ghoshal, and Kabir Dasgupta. "Dynamic analysis of a hydraulic motor drive with variable inertia flywheel." Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering 234, no. 6 (September 25, 2019): 734–47. http://dx.doi.org/10.1177/0959651819875914.
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A flywheel is presented in this article, which can adaptively generate variable inertia in response to the application requirements in a hydraulic drive. The said flywheel consists of four sliders in the guide track of a host flywheel frame which change its position as the rotational speed of the flywheel varies. The varying distance between the slider and the center of rotation leads to a variable inertial mass. This passive inertial mass has a potential to reduce the speed fluctuations of the drive. A comparative study has been made on the effects of the variable inertia flywheel on the hydraulic motor speed fluctuations with that of the fixed inertia flywheel. In this respect, a bond graph model of the hydraulic motor drive with the variable inertia flywheel and the fixed inertia flywheel is developed to analyze their performances. The variable inertia generated by the variable inertia flywheel reduces the hydraulic motor speed fluctuations in response to the changes in the excitation inputs. The tests were conducted to validate the model for step change in speed of the hydraulic motor. The test results of the hydraulic motor speed response are found in good agreement with the predicted response. The proposed design of the flywheel reduces the peak speed of the hydraulic motor that enhances the reliability and performance of the drive.
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PIGNATEL, FLORENT, MAXIME NICOLAS, and ÉLISABETH GUAZZELLI. "A falling cloud of particles at a small but finite Reynolds number." Journal of Fluid Mechanics 671 (February 17, 2011): 34–51. http://dx.doi.org/10.1017/s0022112010005501.
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Through a comparison between experiments and numerical simulations, we have examined the dynamics of a cloud of spheres at a small but finite Reynolds number. The cloud is seen to flatten and to transition into a torus, which further widens and eventually breaks up into droplets. While this behaviour bears some similarity to that observed at zero inertia, the underlying physical mechanisms differ. Moreover, the evolution of the cloud deformation is accelerated as inertia is increased. Two inertial regimes in which macro-scale inertia and micro-scale inertia become successively dominant are clearly identified.
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Thomas, Leif N., and John R. Taylor. "Damping of inertial motions by parametric subharmonic instability in baroclinic currents." Journal of Fluid Mechanics 743 (March 4, 2014): 280–94. http://dx.doi.org/10.1017/jfm.2014.29.
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AbstractA new damping mechanism for vertically-sheared inertial motions is described involving an inertia–gravity wave that oscillates at half the inertial frequency, $f$, and that grows at the expense of inertial shear. This parametric subharmonic instability forms in baroclinic, geostrophic currents where thermal wind shear, by reducing the potential vorticity of the fluid, allows inertia–gravity waves with frequencies less than $f$. A stability analysis and numerical simulations are used to study the instability criterion, energetics, and finite-amplitude behaviour of the instability. For a flow with uniform shear and stratification, parametric subharmonic instability develops when the Richardson number of the geostrophic current nears $Ri_{PSI}=4/3+\gamma \cos \phi $, where $\gamma $ is the ratio of the inertial to thermal wind shear magnitude and $\phi $ is the angle between the inertial and thermal wind shears at the initial time. Inertial shear enters the instability criterion because it can also modify the potential vorticity and hence the minimum frequency of inertia–gravity waves. When this criterion is met, inertia–gravity waves with a frequency $f/2$ and with flow parallel to isopycnals amplify, extracting kinetic energy from the inertial shear through shear production. The solutions of the numerical simulations are consistent with these predictions and additionally show that finite-amplitude parametric subharmonic instability both damps inertial shear and is itself damped by secondary shear instabilities. In this way, parametric subharmonic instability opens a pathway to turbulence where kinetic energy in inertial shear is transferred to small scales and dissipated.
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Du, Fu, Chao Wang, and Wei Nie. "Modeling and Experimental Study of the Dual Cylinder Fluid Inerter." Applied Sciences 12, no. 21 (October 26, 2022): 10849. http://dx.doi.org/10.3390/app122110849.
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The fluid inerter is a new mechanical element which has received great attention in the field of vibration reduction. However, due to the influence of secondary flow in the curved channel, the damping force is too large and the inertia force is relatively small, which limits the engineering applications of the single-cylinder fluid inerter. To eliminate the influence of secondary flow in the single-cylinder fluid inerter, this paper proposes a dual-cylinder fluid inerter that has a straight tube instead of the spiral pipe or spiral groove. We Analyze the working principle, derive conditions of free movement, establish the damping force and inertia force model, and prove the validity of the model through bench testing. Contrastingly, it is found that the maximum parasitic damping force is only 40.32% of the single-cylinder structure, but the inertia force increases to 180.96% of the single-cylinder structure. The proposed inerter greatly increases the proportion of inertia force, and provides a new scheme for engineering applications.
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Xu, Bingyu, Shuquan Wang, Liping Zhao, and Long Zhang. "Impact-Rebound Momentum Excitation Based Inertial Parameters and State Estimation of Defunct Space Object." Aerospace 10, no. 1 (January 1, 2023): 38. http://dx.doi.org/10.3390/aerospace10010038.
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Obtaining the inertia tensors of defunct space objects is essential in on-orbit missions. When the inertia tensor of the space object is non-diagonal, the problem becomes challenging. In this case, the system does not have enough information to estimate the six independent parameters of the inertia tensor. In this paper, the problem of estimating the inertial parameters of a defunct space object with non-diagonal inertia tensor is studied. An excitation method of ejecting an impact ball from the tracking spacecraft to the object is proposed to estimate the complete inertial parameters of the object. The impact ball rebounds after colliding with the object and crashes into the atmosphere finally. After the collision, the angular momentum of the space object changes. The change is used to construct the estimation model. This paper designs an estimation model which consists of two Unscented Kalman-based estimators to estimate the inertial parameters and the motion states of the object. The observability of the estimators is proved through the observability theorem of nonlinear systems. Numerical simulations show that the estimation model is effective in estimating the complete inertial parameters of defunct objects, as well as reducing the measurement errors of the position and attitude of the object.
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Ma, Dezhi, and Wenyi Li. "Wind-Storage Combined Virtual Inertial Control Based on Quantization and Regulation Decoupling of Active Power Increments." Energies 15, no. 14 (July 17, 2022): 5184. http://dx.doi.org/10.3390/en15145184.
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With the increasing proportion of wind turbines in power grids, they are required to have capabilities of active and efficient virtual inertial response to maintain grid frequency stability. However, the virtual inertial control methods currently used in doubly-fed induction generator (DFIG) units suffer from a secondary frequency drop (SFD) problem. Although the SFD can be inhibited by reducing the active power support strength of the DFIG units during inertia response, it will undoubtedly weaken the virtual inertia of the units. Therefore, how to eliminate the SFD while increasing the virtual inertia of the units is a worthy issue for studying. To solve this issue, a wind-storage combined virtual inertial control system based on quantization and regulation decoupling of active power increments is proposed in this paper. First, by setting the parameters of a proportional–differential (P-D) algorithm, the total active power increments required for virtual inertial response are quantified at the DFIG level. Secondly, a curve-shifting method based on the rate of change of frequency is adopted to adjust the active power output of the DFIG units. Finally, a battery energy storage system (BESS) is used to compensate for the power shortages of the units according to the quantized value of the active power increments. Simulations show that the control method can not only eliminate SFD but also effectively increase the system’s virtual inertia.
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Worsnopp, Tom, Michael Peshkin, Kevin Lynch, and J. Edward Colgate. "Controlling the Apparent Inertia of Passive Human-Interactive Robots." Journal of Dynamic Systems, Measurement, and Control 128, no. 1 (November 14, 2005): 44–52. http://dx.doi.org/10.1115/1.2168165.
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Passive robotic devices may exhibit a spatially varying apparent inertia perceptible to a human user. The apparent inertia is the projection of the inertia matrix onto the instantaneous direction of motion. The spatial variation is due to the configuration dependence of the inertia matrix and relevant to many passive mechanisms, including programmable constraint machines or “cobots,” which use low-power steering actuators to choose the direction of motion. We develop two techniques for controlling the apparent inertia in cobots to emulate the desired inertial properties of a virtual object or mechanism. The first is a path-limiting method, which constraints the cobot to steer along certain paths where the apparent inertia and desired inertia are equivalent. The second uses a low-power actuator to control the apparent inertia by driving the device along its direction of motion. We illustrate these ideas for a two-link cobot we have built for experiments in human motor control and rehabilitation. For the actuated control method, we show that the power actuator can be relatively low power compared to the actuators of a traditional robot performing similar tasks.
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Sarojini, Ratnam Kamala, Palanisamy Kaliannan, Yuvaraja Teekaraman, Srete Nikolovski, and Hamid Reza Baghaee. "An Enhanced Emulated Inertia Control for Grid-Connected PV Systems with HESS in a Weak Grid." Energies 14, no. 6 (March 19, 2021): 1721. http://dx.doi.org/10.3390/en14061721.
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The role of renewable energy sources in the power grid is increasing tremendously. However, power electronic converters are used to incorporate RES into the grid without inertia. This article recommends an improved emulated inertia control approach focused on the frequency deviation and rate of change of frequency to enhance the inertia of a power system. The required inertial power calculated from emulated inertia control is delivered through hybrid energy storage systems equipped with a proper hybrid energy storage system control. The fast-varying power calculated from emulated inertia control is linked to super-capacitor. Simultaneously, the battery handles the slow varying power by regulating the DC bus voltage proportionate to the frequency variations. Further, the stability of the emulated inertia control and hybrid energy storage system controller is validated by Bode plots. The simulation results verified the correctness of the proposed emulated inertia control and hybrid energy storage system control. The real-time simulation results with the help of OPAL-RT are presented to validate the proposed method’s feasibility.
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Sarojini, Ratnam Kamala, Kaliannan Palanisamy, and Enrico De Tuglie. "A Fuzzy Logic-Based Emulated Inertia Control to a Supercapacitor System to Improve Inertia in a Low Inertia Grid with Renewables." Energies 15, no. 4 (February 12, 2022): 1333. http://dx.doi.org/10.3390/en15041333.
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The contribution of power generation from converter-dominated renewable energy sources (RES) has increased enormously. Consequently, the system inertia is decreasing, and it impacts the frequency of the system. With large-scale integration of power electronic inverter-based power generation from RES, inertia from energy storage devices would be unavoidable in future power grids. In this paper, the inertia emulator is formed with a supercapacitor (IE–SC) to improve inertia in a low inertia grid. To emulate the inertia in a low inertia grid, this paper proposes a fuzzy logic controller-based emulated inertia controller (FL-EIC) for an inverter attached to IE–SC. The proposed fuzzy logic controller estimates the inertial power required based on the frequency deviation and rate of change of frequency (ROCOF). The output of the fuzzy controller adds to the conventional emulated inertia control (EIC) technique to alter the load angle for the power electronic inverter of IE–SC. Specifically, the proposed FL-EIC achieves inertia emulation by proportionally linking the time derivative of the grid frequency and frequency deviation to active power references of IE–SC. A comparison of the conventional EIC and FL-EIC is carried out to prove the effectiveness of the proposed FL-EIC. Furthermore, real-time simulations with the help of the OPAL-RT real-time simulator (OP 5700) are presented to validate the advantage of the FL-EIC.
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Zou, Wei, Yuxuan Chen, D. V. Senthilkumar, and Jürgen Kurths. "Oscillation quenching in diffusively coupled dynamical networks with inertial effects." Chaos: An Interdisciplinary Journal of Nonlinear Science 32, no. 4 (April 2022): 041102. http://dx.doi.org/10.1063/5.0087839.
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Self-sustained oscillations are ubiquitous and of fundamental importance for a variety of physical and biological systems including neural networks, cardiac dynamics, and circadian rhythms. In this work, oscillation quenching in diffusively coupled dynamical networks including “inertial” effects is analyzed. By adding inertia to diffusively coupled first-order oscillatory systems, we uncover that even small inertia is capable of eradicating the onset of oscillation quenching. We consolidate the generality of inertia in eradicating oscillation quenching by extensively examining diverse quenching scenarios, where macroscopic oscillations are extremely deteriorated and even completely lost in the corresponding models without inertia. The presence of inertia serves as an additional scheme to eradicate the onset of oscillation quenching, which does not need to tailor the coupling functions. Our findings imply that inertia of a system is an enabler against oscillation quenching in coupled dynamical networks, which, in turn, is helpful for understanding the emergence of rhythmic behaviors in complex coupled systems with amplitude degree of freedom.
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Yang, Li, and Zhijian Hu. "Implementation of Dynamic Virtual Inertia Control of Supercapacitors for Multi-Area PV-Based Microgrid Clusters." Sustainability 12, no. 8 (April 18, 2020): 3299. http://dx.doi.org/10.3390/su12083299.
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In order to improve the dynamic stability of multi-area microgrid (MG) clusters in the autonomous mode, this study proposes a novel fuzzy-based dynamic inertia control strategy for supercapacitors in multi-area autonomous MG clusters. By virtue of the integral manifold theory, the interactive influence of inertia on dynamic stability for multi-area MG clusters is explored in detail. The energy function of multi-area MG clusters is constructed to further analyze the inertia constant. Based on the analysis of the mechanism, a control strategy for the fuzzy-based dynamic inertia control of supercapacitors for multi-area MG clusters is further proposed. For each sub-microgrid (sub-MG), the gain of the fuzzy-based dynamic inertia control is self-tuned dynamically, with system events being triggered, so as to flexibly and robustly enhance the dynamic performance of the multi-area MG clusters in the autonomous mode. To verify the effectiveness of the proposed control scheme, a three-area photovoltaic (PV)-based MG cluster is designed and simulated on the MATLAB/Simulink platform. Moreover, a comparison between the dynamic fuzzy-based inertial control method and an additional droop control method is finally presented to validate the advantages of the fuzzy-based dynamic inertial control approach.
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Ibrahim, Ismail, Cathal O’Loughlin, and Terence O’Donnell. "Virtual Inertia Control of Variable Speed Heat Pumps for the Provision of Frequency Support." Energies 13, no. 8 (April 11, 2020): 1863. http://dx.doi.org/10.3390/en13081863.
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The growth in the integration of converter interfaced renewable energy has reduced the system inertia, which threatens system stability due to high rate of change of frequency (RoCoF) and frequency nadir issues unless steps are taken to mitigate it. There is a need to provide sufficient fast frequency response to maintain adequate inertia in the system. This paper investigates the capabilities of a variable speed heat pump to provide an emulated inertial response. This paper presents a virtual synchronous machine control for a variable speed heat pump that provides support for grid frequency regulation over the inertial response time frame. A small-signal model with the transfer function of the variable speed heat pump is developed to analyse the effectiveness and feasibility of providing virtual inertia at the device and grid level, respectively. Furthermore, the small-signal model is validated using hardware in the loop simulation. Finally, the aggregated frequency response and virtual inertia contribution by a population of the heat pumps are evaluated and quantified in an urban distribution system.
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Nguyen, Nang Van, Yasuhiro Harada, Hiroki Takimoto, and Kota Shimomoto. "Measurement of Static Lateral Stability Angle and Roll Moment of Inertia for Agricultural Tractors with Attached Implements." Journal of Agricultural Safety and Health 26, no. 1 (2020): 15–29. http://dx.doi.org/10.13031/jash.13610.
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Highlights Keywords: Implement, Inertial parameter, Lateral stability, Moment of inertia, Rollover, Tractor.Static lateral stability of agricultural tractors with mounted rotary tillers was analyzed. Keywords: Implement, Inertial parameter, Lateral stability, Moment of inertia, Rollover, Tractor.The mounted implement increased static lateral stability of tractors in phase I rollover but decreased static lateral stability in phase II rollover. Keywords: Implement, Inertial parameter, Lateral stability, Moment of inertia, Rollover, Tractor.A mounted implement may significantly reduce the static lateral stability of agricultural tractors and increase the risk of tractor side overturn. Keywords: Implement, Inertial parameter, Lateral stability, Moment of inertia, Rollover, Tractor. ABSTRACT. Each year, many fatalities result from rollovers of agricultural tractors in Japan. In addition to rollover protective structures (ROPS) and seat belts, a warning device that alerts the operator of impending rollover based on the tractor stability index is a measure used to prevent rollovers. The stability index requires inertial parameters, which have been measured only for the single body of the tractor, to calculate the warning threshold. In this study, the center of gravity (CoG) and lateral stability angles of three agricultural tractors were measured, and lateral stability angles were also calculated and compared with measured values for three tractor-tiller combinations to analyze the effect of the attached implement on the tractor stability as well as to verify the accuracy of the calculation methods. The roll moment of inertia (RMI) was also measured for two tractors and two rotary tillers, and RMI values for tractor-tiller combinations were calculated. The measurement and calculation results show that the attached implement increased the lateral stability angle of tractors in phase I rollover and decreased the lateral stability angle in phase II rollover, and for a certain tractor-tiller combination, there was no transition from phase I to phase II rollover. The difference between the measured and calculated lateral stability angles in phase I ranged from -3.5° to 2.5°, while that in phase II ranged from 0.2° to 5.2°. The RMI about the longitudinal axis through the CoG was 203 and 433 kg m-2 for tractors A and B, respectively, and 52 and 94 kg m-2 for rotary tillers D and F, respectively. The calculated RMI values were 265 and 540 kg m-2 for tractor-tiller combinations A-D and B-E, respectively. Keywords: Implement, Inertial parameter, Lateral stability, Moment of inertia, Rollover, Tractor.
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Hu, Jian, Lei Xu, Sangdu Guo, Yiming Sun, and Gangyan Li. "Study on Inertia Load Resistance Analysis Method of Light Truck Door Latch." Applied Sciences 12, no. 9 (April 21, 2022): 4171. http://dx.doi.org/10.3390/app12094171.
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Aiming at the problem of door opening caused by the unlocking of the side door latch system under the action of inertial force when the car is in a side impact, this paper takes a light truck door latch as the research object, and proposes an inertia load resistance analysis method combining theoretical calculation and simulation analysis. Through the theoretical calculation of inertia load resistance of the door latch, the force of each part and the rotation of the pawl are analyzed. We perform inertia load resistance simulation analysis on the latch to verify the reliability of the theoretical calculation results. If the theoretical calculation result is that the latch will be unlocked under the inertia load of 60 g (588 m/s2), we compare the force of each part in the theoretical calculation process with the normal opening condition of the latch to provide a basis for the optimization of the latch structure. Finally, theoretical calculations and a simulation analysis are carried out on the optimized results again, and a latch structure that meets the requirements of the inertia load resistance is obtained. Since the results obtained from the inertia load resistance simulation analysis are basically consistent with the theoretical calculation results of the inertia load resistance and the inertia load resistance simulation requires a lot of computing time, after the verification of the inertia load resistance simulation analysis, firstly, the inertia load resistance simulation step can be omitted in the subsequent structural optimization process.
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Agrawal, S. K. "Series-Chain Planar Manipulators: Inertial Singularities." Journal of Mechanical Design 115, no. 4 (December 1, 1993): 941–45. http://dx.doi.org/10.1115/1.2919291.
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Often, the dynamic behavior of multi-degree-of-freedom mechanical systems such as robots and manipulators is studied by computer simulation of their dynamic equations. An important step in the simulation is the inversion of a matrix, often known as the inertia matrix of the system. In the configurations, where the inertia matrix is singular, the simulation is prone to large numerical errors. Commonly, it is believed that this inertia matrix is always positive definite (or, nonsingular) no matter what geometric and inertial attributes are assigned to the links. In this paper, we show that the inertia matrix of a multi-degree-of-freedom mechanical system modeled with point masses can be singular at special configurations of the links. We present a way to systematically enumerate some of these configurations where the inertia matrix for planar series-chain manipulators built with revolute and prismatic joints are singular.
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Yan, Gang Yi. "An Adjustable Inertia Balance Support for High-Speed Scanning Probe Microscope." Advanced Materials Research 1061-1062 (December 2014): 735–38. http://dx.doi.org/10.4028/www.scientific.net/amr.1061-1062.735.
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An adjustable inertia balance support is proposed to counterbalance the inertial force from the actuators for high performance scanning probe microscope. The adjusting method is based on voltage proportion control. In contrast with traditional method that adding or removing mass, it is very convenient to adjust to minimize the inertial force transmitted to the supporting base. It may have a promising application on the current inertia balance support structure, which is used in some high-speed scanning probe microscope. What is more, it has a very good compatibility with current structure.
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STARK, HANS-ULRICH, CLAUDIO J. TESSONE, and FRANK SCHWEITZER. "SLOWER IS FASTER: FOSTERING CONSENSUS FORMATION BY HETEROGENEOUS INERTIA." Advances in Complex Systems 11, no. 04 (August 2008): 551–63. http://dx.doi.org/10.1142/s0219525908001805.
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We investigate an extension of the voter model in which voters are equipped with an individual inertia to change their opinion. This inertia depends on the persistence time of a voter's current opinion (ageing). We focus on the case of only two different inertia values: zero if a voter just changed toward a new opinion, and ν otherwise. We are interested in the average time to reach consensus, i.e. the state in which all voters have adopted the same opinion. Adding inertia to the system means to slow down the dynamics at the voter's level, which should presumably lead to slower consensus formation. As an unexpected outcome of our inertial voter dynamics, there is a parameter region of ν where an increasing inertia leads to faster consensus formation. These results rest on the heterogeneity of voters which evolves through the described ageing. In a control setting of homogeneous inertia values, we only find monotonously increasing consensus times. In this paper, we present dynamical equations for the mean field case which allow for analytical insight into the observed slower-is-faster effect.
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Peña Asensio, Andrés, Francisco Gonzalez-Longatt, Santiago Arnaltes, and Jose Luis Rodríguez-Amenedo. "Analysis of the Converter Synchronizing Method for the Contribution of Battery Energy Storage Systems to Inertia Emulation." Energies 13, no. 6 (March 20, 2020): 1478. http://dx.doi.org/10.3390/en13061478.
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This paper presents a comprehensive analysis of the effect of the converter synchronizing methods on the contribution that Battery Energy Storage Systems (BESSs) can provide for the support of the inertial response of a power system. Solutions based on phase-locked loop (PLL) synchronization and virtual synchronous machine (VSM) synchronization without PLL are described and then compared by using time-domain simulations for an isolated microgrid (MG) case study. The simulation results showed that inertial response can be provided both with and without the use of a PLL. However, the behavior in the first moments of the inertia response differed. For the PLL-based solutions, the transient response was dominated by the low-level current controllers, which imposed fast under-damped oscillations, while the VSM systems presented a slower response resulting in a higher amount of energy exchanged and therefore a greater contribution to the support of the system inertial response. Moreover, it was demonstrated that PLL-based solutions with and without derivative components presented similar behavior, which significantly simplified the implementation of the PLL-based inertia emulation solutions. Finally, results showed that the contribution of the BESS using VSM solutions was limited by the effect of the VSM-emulated inertia parameters on the system stability, which reduced the emulated inertia margin compared to the PLL-based solutions.
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Meng, Fan-Ming, Sheng Yang, Zhi-Tao Cheng, Yong Zheng, and Bin Wang. "Effect of fluid inertia force on thermal elastohydrodynamic lubrication of elliptic contact." Mechanics & Industry 22 (2021): 13. http://dx.doi.org/10.1051/meca/2021010.
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A non-Newtonian thermal elastohydrodynamic lubrication (TEHL) model for the elliptic contact is established, into which the inertia forces of the lubricant is incorporated. In doing so, the film pressure and film temperature are solved using the associated equations. Meanwhile, the elastic deformation is calculated with the discrete convolution and fast Fourier transform (DC-FFT) method. A film thickness experiment is conducted to validate the TEHL model considering the inertia forces. Further, effects of the inertia forces on the TEHL performances are studied at different operation conditions. The results show that when the inertia forces are considered, the central and minimum film thicknesses increase and film temperature near the inlet increases obviously. Moreover, the inertial solution of the central film thickness is closer to the experimental result compared with its inertialess value.
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McCulloch, Michael E., and Jaume Giné. "Modified inertial mass from information loss." Modern Physics Letters A 32, no. 28 (September 4, 2017): 1750148. http://dx.doi.org/10.1142/s0217732317501486.
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A modification of inertia (called MiHsC or quantized inertia) has been proposed that assumes that inertia is caused by Unruh radiation, and that this radiation is made inhomogeneous in space by either Rindler horizons caused by acceleration or the distant Hubble horizon. The former predicts the standard inertial mass, and the latter predicts galaxy rotation without dark matter and cosmic acceleration without dark energy. It is proposed here that this model can be derived in an alternative way by assuming that the sum of mass (M), energy (E) and the information content of horizons (I) is conserved (EMI) so that mass–energy is released in a discrete manner when the area of a Rindler horizon reduces. This model could be tested by looking for the quantization of inertial mass and acceleration at very high accelerations, and may provide an explanation for the cosmological constant problem.
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Wang, G., and D. H. Richter. "Two mechanisms of modulation of very-large-scale motions by inertial particles in open channel flow." Journal of Fluid Mechanics 868 (April 15, 2019): 538–59. http://dx.doi.org/10.1017/jfm.2019.210.
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Very-large-scale motions (VLSMs) and large-scale motions (LSMs) coexist at moderate Reynolds numbers in a very long open channel flow. Direct numerical simulations two-way coupled with inertial particles are analysed using spectral information to investigate the modulation of VLSMs. In the wall-normal direction, particle distributions (mean/preferential concentration) exhibit two distinct behaviours in the inner flow and outer flow, corresponding to two highly anisotropic turbulent structures, LSMs and VLSMs. This results in particle inertia’s non-monotonic effects on the VLSMs: low inertia (based on the inner scale) and high inertia (based on the outer scale) both strengthen the VLSMs, whereas moderate and very high inertia have little influence. Through conditional tests, low- and high-inertia particles enhance VLSMs following two distinct routes. Low-inertia particles promote VLSMs indirectly through the enhancement of the regeneration cycle (the self-sustaining mechanism of LSMs) in the inner region, whereas high-inertia particles enhance the VLSM directly through contribution to the Reynolds shear stress at similar temporal scales in the outer region. This understanding also provides more general insight into inner–outer interaction in high-Reynolds-number, wall-bounded flows.
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Morgan, Robert. "Inertia." College English 48, no. 4 (April 1986): 353. http://dx.doi.org/10.2307/377260.
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Wolf, Alisa. "Inertia." Red Cedar Review 45, no. 1 (2010): 55–60. http://dx.doi.org/10.1353/rcr.0.0079.
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Hoffbuhr, Jack W. "Inertia." Journal - American Water Works Association 99, no. 6 (June 2007): 6. http://dx.doi.org/10.1002/j.1551-8833.2007.tb07964.x.
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Yan, Huaidong, Haoyuan Li, Lihua Cai, Anping Hu, and Zhao Liu. "Research on inertial response control technology of high voltage direct hanging energy storage system." E3S Web of Conferences 252 (2021): 01049. http://dx.doi.org/10.1051/e3sconf/202125201049.
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The high voltage direct hanging energy storage system can effectively solve the problems of fluctuation and intermittence caused by environmental factors, and improve the ability of power system to absorb new energy. By controlling the energy storage, the new energy station has certain inertia and damping characteristics, so that the new energy power station can be connected to the grid friendlier. Starting from the time scale division method of inertial response control, this paper studies the energy demand of inertial response of large-scale new energy power station in different time scales, and gives the inertial response control strategy under different time scales. The model of high voltage direct hanging energy storage system is established, and the inertia response characteristics control technology is verified.
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Li, Shi Wu, Jing Jing Tian, Zhi Fa Yang, Hai Zheng Wang, and Lin Hong Wang. "Design and Test Analysis of Precise and Fractionized Inertia System of Tire Drum Test-Bed." Advanced Materials Research 199-200 (February 2011): 137–42. http://dx.doi.org/10.4028/www.scientific.net/amr.199-200.137.
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To analyze the relationship of brake performances and its influence factors, a kind of tire drum test-bed was designed. The gradation principle of flywheels was proposed based on the double multiplication method and an inertial system with eight steps of flywheels was put forward. The inertia-mass of tire load ranging 400 from 5000 kilograms was divided into 256 levels with the accuracy of ±10 kilograms. The dynamics simulation model was built using SOLIDWORKS and ADAMS. The program of acceleration and brake testing were schemed. The feasibility and accuracy of design methodology of test-bed inertial system were verified by the comparison analysis of simulation and road test. The accurate matching between the moment of inertia of test-bed inertial system and tire load was realized.
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Mwasame, Paul M, Norman J Wagner, and Antony N Beris. "Micro-Inertia Effects in Material Flow." Journal of Non-Equilibrium Thermodynamics 44, no. 3 (July 26, 2019): 235–46. http://dx.doi.org/10.1515/jnet-2018-0072.
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Abstract The mechanics of understanding a new application of the bracket theory of Non-Equilibrium Thermodynamics that allows for the incorporation of microstructural inertia effects within conformation tensor-based constitutive models of macroscopic material behavior is presented. Introducing inertia effects generally requires the replacement of a first order in time evolution equation for the conformation tensor by a second order one. Through the analysis of a simple damped oscillator we bring forward here the close connection to the structural dissipation brackets present in the two cases, with the weights being inverted as one transitions from the inertialess to the inertial description. Moreover, one may also describe inertial effects in material flow in certain situations through a simple modification of the first order evolution equation for the conformation tensor, which consists of adding a new non-affine term that couples the conformation and the vorticity tensors, as detailed in a recent publication (P. M. Mwasame, N. J. Wagner and A. N. Beris, Phys. Fluids, 30 (2018), 030704). As shown there, when applied to the low particle Reynolds flow of dilute emulsions, this reduced inertial flow model provides predictions consistent with literature-available microscopically based asymptotic results.
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Allen, J. Daniel, Frederic R. Curtiss, and Kathleen A. Fairman. "Nonadherence, Clinical Inertia, or Therapeutic Inertia?" Journal of Managed Care Pharmacy 15, no. 8 (October 2009): 690–95. http://dx.doi.org/10.18553/jmcp.2009.15.8.690.
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Xie, Xin-Yu, Chun-Tai Xu, Jin-Zhu Li, Zhong-Jin Wang, and Wen-Jun Wang. "Study on One-Dimensional Large Deformation Consolidation of Soil considering Liquid Phase Inertia." Mathematical Problems in Engineering 2020 (May 20, 2020): 1–12. http://dx.doi.org/10.1155/2020/9028495.
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Classical consolidation theory ignores the influence of soil liquid phase acceleration. This paper considers the influence of liquid phase acceleration on the stress balance equation during the consolidation of soil, obtains the one-dimensional equation governing quasi-hydrostatic consolidation under large deformation with the consideration of the inertia of the liquid phase, and solves the governing equations by finite element method. The calculation results show that the liquid phase inertia effect of the soil will cause excess pore pressure in the soil, obviously increasing in the initial stage of consolidation, and the self-weight of soil exerts an influence on the excess pore pressure at the later stages of consolidation. The liquid phase inertia effect parameter Dc determines the strength of the liquid phase inertia effect. A larger Dc value results in a larger increase in the excess pore pressure, and the later the liquid phase inertial effect occurs, the longer the duration is. In the large strain consolidation analysis, especially at the initial stage of consolidation, it is necessary to consider the liquid phase inertia effect of the soil.
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Jumarie, Guy. "Trajectory control of manipulators with time varying inertia links." Robotica 6, no. 3 (July 1988): 197–202. http://dx.doi.org/10.1017/s0263574700004306.
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SUMMARYOne way to increase the flexibility (or versatility) of manipulators is to use links with time varying inertia. One can then control both the joint torques and the inertias of the links therefore more pliancy in the practical utilisation of the arm. The paper deals with the Lagrangian formulation of the corresponding inertia control problem which can be considered either in open loop or in closed loop form. The general equations are derived and it is shown that one so obtains a set of uncoupled Ricatti differential equations which define the dynamics of the structural inertias. Problems related to stabilization and to structural parameter uncertainty are also considered.
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Lorås, Håvard, Gertjan Ettema, and Stig Leirdal. "The Muscle Force Component in Pedaling Retains Constant Direction across Pedaling Rates." Journal of Applied Biomechanics 25, no. 1 (February 2009): 85–92. http://dx.doi.org/10.1123/jab.25.1.85.
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Changes in pedaling rate during cycling have been found to alter the pedal forces. Especially, the force effectiveness is reduced when pedaling rate is elevated. However, previous findings related to the muscular force component indicate strong preferences for certain force directions. Furthermore, inertial forces (due to limb inertia) generated at the pedal increase with elevated pedaling rate. It is not known how pedaling rate alters the inertia component and subsequently force effectiveness. With this in mind, we studied the effect of pedal rate on the direction of the muscle component, quantified with force effectiveness. Cycle kinetics were recorded for ten male competitive cyclists at five cadences (60–100 rpm) during unloaded cycling (to measure inertia) and at a submaximal load (~260 W). The force effectiveness decreased as a response to increased pedaling rate, but subtracting inertia eliminated this effect. This indicates consistent direction of the muscle component of the foot force.
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Liu, Liangkun, Ping Tan, Haitao Ma, Weiming Yan, and Fulin Zhou. "A novel energy dissipation outrigger system with rotational inertia damper." Advances in Structural Engineering 21, no. 12 (February 22, 2018): 1865–78. http://dx.doi.org/10.1177/1369433218758475.
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Rotational inertia damper, a novel damper, possessing the advantage of displacement amplification, has been employed in outrigger system for seismic mitigation. The equivalent analysis model composed by a uniform cantilever beam and an equivalent spring was proposed to simulate the rotational inertia damper outrigger system, by which the corresponding dynamic characteristic equation was derived based on numerical assembly technique. To gain the response of the damped system, finite element method and state space method have been utilized. Finally, the results show that the pseudo-undamped natural frequency ratios and system modal damping ratios are significantly influenced by stiffness parameter of the exterior column, while the mass parameter of the rotational inertia damper has little effect on them. The optimal damping ratio can be acquired for one mode, but it may be worse for the other mode in the same position equipping rotational inertia damper. Furthermore, numerical simulation results for the typical earthquake records have verified that the rotational inertia damper outrigger has excellent control performance in displacement as well as acceleration. A good agreement between damping force and equivalent force also suggests that the damping force of rotational inertia damper is predominant and the inertial force has no significant effect on the structure.
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Shin, Joong Ho, Myung Gwon Lee, Sungyoung Choi, and Je-Kyun Park. "Inertia-activated cell sorting of immune-specifically labeled cells in a microfluidic device." RSC Adv. 4, no. 74 (2014): 39140–44. http://dx.doi.org/10.1039/c4ra06296e.
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Wang, G., and D. H. Richter. "Modulation of the turbulence regeneration cycle by inertial particles in planar Couette flow." Journal of Fluid Mechanics 861 (December 28, 2018): 901–29. http://dx.doi.org/10.1017/jfm.2018.936.
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Two-way coupled direct numerical simulations are used to investigate the effects of inertial particles on self-sustained, turbulent coherent structures (i.e. the so-called regeneration cycle) in plane Couette flow at low Reynolds number just above the onset of transition. Tests show two limiting behaviours with increasing particle inertia, similar to the results from previous linear stability analyses: low-inertia particles trigger the laminar-to-turbulent instability whereas high-inertia particles tend to stabilize turbulence due to the extra dissipation induced by particle–fluid coupling. Furthermore, it is found that the streamwise coupling between phases is the dominant factor in damping of the turbulence and is highly related to the spatial distribution of the particles. The presence of particles in different turbulent coherent structures (large-scale vortices or large-scale streaks) determines the turbulent kinetic energy of particulate phase, which is related to the particle response time scaled by the turnover time of large-scale vortices. By quantitatively investigating the periodic character of the whole regeneration cycle and the phase difference between linked sub-steps, we show that the presence of inertial particles does not alter the periodic nature of the cycle or the relative length of each of the sub-steps. Instead, high-inertia particles greatly weaken the large-scale vortices as well as the streamwise vorticity stretching and lift-up effects, thereby suppressing the fluctuating amplitude of the large-scale streaks. The primary influence of low-inertia particles, however, is to strengthen the large-scale vortices, which fosters the cycle and ultimately reduces the critical Reynolds number.
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SKJETNE, E., A. HANSEN, and J. S. GUDMUNDSSON. "High-velocity flow in a rough fracture." Journal of Fluid Mechanics 383 (March 25, 1999): 1–28. http://dx.doi.org/10.1017/s0022112098002444.
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We simulate high-velocity flow in a self-affine channel with a constant perpendicular opening by solving numerically the Navier–Stokes equations, and analyse the resulting flow qualitatively and quantitatively. At low velocity, i.e. vanishing inertia, the effective permeability is dominated by the narrowest constrictions measured perpendicular to the local flow direction and the flow field tends to fill the channel due to the diffusion generated by the viscous term in the Stokes equation. At high velocity (strong inertia), the high-velocity zones of the flow field resemble a narrow tube of essentially constant thickness in the direction of flow, since the transversal diffusion is weak compared to the longitudinal convection. The thickness of the flow tube decreases with Reynolds number. This narrowing in combination with mass balance results in an average velocity in the flow tube which increases faster with Reynolds number than the average velocity in the fracture. In the low-velocity zones, recirculation zones appear and the pressure is almost constant.The flow tube consists of straight sections. This is due to inertia. The local curvature of the main stream reflects the flow-tube/channel-wall interaction. A boundary layer is formed where the curvature is large. This boundary layer is highly dissipative and governs the large pressure loss (inertial resistance) of the medium. Quantitatively, vanishing, weak and strong inertial flow regimes can be described by the Darcy, weak inertia and Forchheimer flow equations, respectively. We observe a cross-over flow regime from the weak to strong inertia, which extends over a relatively large range of Reynolds numbers.
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Gao, Sumei, Longxiang Xu, and Chaowu Jin. "Performance Analysis of Acceleration and Inertial Force of Electromagnetic Suspension Inertial Stabilizer." Applied Sciences 12, no. 11 (May 24, 2022): 5304. http://dx.doi.org/10.3390/app12115304.
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In this paper, the structural characteristics of electromagnetic suspension (EMS) inertial stabilizers are analyzed firstly, and then a mechanical analysis of a single mass block and double mass block is carried out. The relationship model between the inertial anti-rolling mass block and inertial force transmitted to the ship is established. The inertial force is determined by the number of coil turns, coil current, mass block, mass of the ship, electromagnet current, rate of change of the electromagnet current, air gap between the electromagnet and inertial mass block, and rotational angular speed. Through theoretical analysis, it is found that the response speed of inertia force is directly related to the electromagnetic coil current, the voltage at both ends of the electromagnetic coil, the coil resistance and the air gap. It is concluded that the response speed of the inertia force can be controlled by controlling the coil current, adjusting the voltage at both ends of the coil and adjusting the air gap. The inductance of the electromagnetic coil will also increase the nonlinearity of the inertial anti-roll system. On the basis of theoretical analysis, a digital simulation of EMS inertial stabilizer is carried out by MATLAB and ANSYS MAXWELL2D. Finally, a single mass block system of EMS inertial stabilizer is designed and tested. During the test, a 1.5 V sinusoidal excitation voltage is added to the electromagnetic coil after the mass block is suspended stably, and the maximum acceleration values of the inertial anti-rolling mass block and hull are 10.29 m/s2 and 1.27 m/s2. Finally, the theoretical analysis results, digital simulation results and experimental results are analyzed, which verifies the correctness of the acceleration and inertia force performance analysis of the EMS inertial stabilizer.
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WINTERS, K. B. "Growth of inertia–gravity waves in sheared inertial currents." Journal of Fluid Mechanics 601 (April 25, 2008): 85–100. http://dx.doi.org/10.1017/s0022112008000621.
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The linear stability of inviscid non-diffusive density-stratified shear flow in a rotating frame is considered. A temporally periodic base flow, characterized by vertical shear S, buoyancy frequency N and rotation frequency f, is perturbed by infinitesimal inertia–gravity waves. The temporal evolution and stability characteristics of the disturbances are analysed using Floquet theory and the growth rates of unstable solutions are computed numerically. The global structure of solutions is addressed in the dimensionless parameter space (N/f, S/f, φ) where φ is the wavenumber inclination angle from the horizontal for the wave-like perturbations. Both weakly stratified rapidly rotating flows (N<f) and strongly stratified slowly rotating flows (N>f) are examined. Distinct families of unstable modes are found, each of which can be associated with nearby stable solutions of periodicity T or 2T where T is the inertial frequency 2π/f. Rotation is found to be a destabilizing factor in the sense that stable non-rotating shear flows with N2/S2>1/4 can be unstable in a rotating frame. Morever, instabilities by parametric resonance are found associated with free oscillations at half and integer multiples of the inertial frequency.
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Martins, Alexandre A., and Mario J. Pinheiro. "On the Electromagnetic Origin of Inertia and Inertial Mass." International Journal of Theoretical Physics 47, no. 10 (March 28, 2008): 2706–15. http://dx.doi.org/10.1007/s10773-008-9709-y.
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Mori, Atsunobu, Katsuyuki Tanaka, and Haruo Mori. "Effects of Fluid Inertia Forces on the Performance of a Plane Inclined Sector Pad for an Annular Thrust Bearing Under Laminar Condition." Journal of Tribology 107, no. 1 (January 1, 1985): 46–52. http://dx.doi.org/10.1115/1.3261001.
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The hydrodynamic wedge of a plane inclined sector pad is analyzed in relation to the lubricant inertia forces under incompressible laminar conditions. Based on the usual assumptions of thin film lubrication theory without the thermal effects, modified Reynolds equations are derived by averaging out all the inertia terms of the Navier-Stokes equations across the film thickness. The equations are linearized with respect to the inertia parameter, and solved numerically for a plane inclined, sectorial configuration. The boundary value of the film pressure at the leading edge is set at the ambient pressure, under the assumption of a negligibly small rampressure thereat. The inertial effects on the static and dynamic performance such as the load carrying capacity, flow rate, frictional torque, position of pressure center, film stiffness, and damping coefficient are discussed, in which the effects of the centrifugal force and those of the other convective inertia forces are compared with each other.