Sudden Imbalance Research Articles

Mechanical and vibration characteristics investigation of the elastic ring squeeze film damper-rotor considering oil film sealing and leakage

Elastic ring squeeze film damper (ERSFD) is extensively used in industrial rotating systems due to its excellent noise control and vibration suppression characteristics. However, the oil film sealing and leakage has a profound effect on the mechanical and vibration characteristics of the ERSFD and the ERSFD-rotor during operation. The sealing and leakage reduce the axial flow of the oil film, leading to changes in the initial boundary conditions of the flow field, which in turn affects the oil film pressure and damping coefficient of ERSFD. Meanwhile, the sealing causes an increase in the oil film force of ERSFD, which in turn affects the response of the rotor system. But there is relatively little research on the impact of sealing and leakage on the dynamic performances of ERSFD-rotor. In this paper, a mathematical model of ERSFD under different sealing conditions (no end seal, complete end seal, piston ring seal, O-ring seal) is established by changing the initial boundary equations of the flow field of ERSFD and the coupled solution of the Reynolds equation of ERSFD with different sealing and leakage boundary equations is realized. Then, the characteristics of oil film pressure and force of ERSFD under different sealing conditions is studied. After that, an ERSFD-rotor model considering oil film sealing and leakage is established based on displacement compatibility conditions and force balance principles. Meanwhile, the impact of sealing and leakage on the amplitude-frequency relation and sudden imbalance of an ERSFD combined support rotor is researched. The research results reveal that good sealing can significantly increase the damping of the system, thereby reducing the vibration amplitude of the ERSFD-rotor system. In addition, good sealing conditions can also shorten the transient process of sudden unbalanced excitation. Finally, the effectiveness of some simulation results was verified through experiments on the ERSFD rotor test bench.

Regulating Shared Employment in Post-Pandemic China

Abstract During the pandemic, shared employment emerged as a market solution to balance the sudden imbalance in labor supply and demand. However, China’s current labor law system lacks clear and strong protection for shared employees, resulting in a mismatch with recent socioeconomic development. This paper highlights a fundamental issue in China’s labor law – the current regulatory system only recognizes the unitary employment relationship. This orientation deprives shared employees of full labor law protection under the protective principle. The paper analyzes two aspects of shared employment in China. First, it examines the evolution of the existing problematic labor law framework and why it fails to match China’s development. Second, this paper proposes basic principles for restructuring China’s labor law system to match its development. The paper concludes with three proposals, including theoretical and political repositioning towards the dual/multiple labor relations path, combining mandatory and autonomous norms to ensure worker protection, and safeguarding compensation for third parties.

The role of NGOs in facing the social and economic repercussions of the corona pandemic in the Islamic society " A field study in Alexandria"

Crises facing a given society represent a milestone in its history as they distinguish social life in its natural form, and its form after the sudden imbalance the society was exposed to. Crises may be economic, social, political, cultural, health-related or medical. They afflict a certain sector with partial paralysis, or permanent breakdown, and each crisis has its victims that are directly affected thereby, or indirectly through its various consequences. In addition, each crisis has its exploiters and beneficiaries who gain benefit therefrom and wish for its permanence. The current study attempts to monitor and analyze the role of NGOs during the different crises the Egyptian society has been exposed to, as each crisis has its impacts in different aspects of life. Among those crises, which emerged recently, is COVID-19 Pandemic. Hence, the problem of the study is to identify the nature of this disease, and the material and social support provided by these institutions in an attempt to face the various impacts of the COVID-19 pandemic, by conducting 30 interviews with NGOs founders, and their representatives within the city of Alexandria. The result has shown that these bodies sought to provide alternative sources of income for the groups that were directly affected by the crisis.

Dynamic Modeling and Vibration Characteristics for a High-Speed Aero-Engine Rotor with Blade Off

Blade off that occurs during operation will generate a sudden imbalance excitation and make the rotor become inertially asymmetric, which leads to large instantaneous impact load and induces more complex rotor dynamic phenomena. In order to study the transient dynamic characteristics for complex rotors suffering from blade off, a mathematical model for solving the response of the gas generator rotor in the aero-turboshaft engine is established based on the FE method and DOF condensation, in which the complex structural characteristics, transient impact load, and inertia asymmetry of the rotor are considered. The complex impeller structure is modeled by piecewise linear fitting with cylindrical beam elements and tapered beam elements. Without loss of generality, the modeling method suitable for complex rotors is verified through a general complex test rotor with modal experiments. Based on this, the responses are solved for carrying out parametric studies and an understanding of the transient dynamic characteristics of the rotor under the extreme working conditions of blade off. The results show that the blade off has a great impact effect on the time-domain waveform, frequency components, and rotor orbits. At the instantaneous stage after blade off, the complex motion is composed of synchronous motion and some lower-order natural modes excited by blade off. Although the transient responses with blade off at different rotational speeds have similar time-varying characteristics, the impact factor is sensitive to the rotating speed. Most important is that the parameter of the blade off location will not only have a significant effect on the impact factor, but also on the frequency spectrum. These dynamic characteristics as well as impact effect provide certain guidance for the fault recognition and dynamic analysis to these complex rotors suffering blade off.

Abnormal Gait Movements Prior to a Near Fall in Individuals After Stroke

ObjectiveTo investigate the abnormal kinematic and kinetic movements in the last gait cycle before a near fall in individuals poststroke, where a near fall is defined as a physical therapist feeling the need to stabilize a patient. DesignRetrospective study. SettingA rehabilitation center. ParticipantsTwenty-five adults (22 men, 3 women; N=25) with an average age of 66.3 years and mean duration from stroke of 4 months who required manual assistance for a sudden imbalance during routine 3-dimensional motion analysis. InterventionsNot applicable. Main Outcome MeasuresWe compared the averaged usual gait cycle and the last cycle before the near-falling gait cycle (pre–near-falling gait cycle). We obtained the following spatiotemporal parameters: gait velocity, gait cycle duration, mediolateral center of mass displacement, step length, step width, joint moments, and angular displacement of the trunk in a cycle. Peak values of joint moments and trunk angle displacement were calculated. ResultsEtiology for near falls included toe trip, mediolateral perturbation, and knee collapse. We found the following significant differences in the pre–near-falling gait cycle compared with the usual gait cycle: decreased gait velocity, prolonged total cycle time, and excessive mediolateral center of mass displacement. ConclusionsDecreased gait velocity, prolonged cycle time, and excessive mediolateral center of mass displacement may be a sign of an impending fall in people with impaired gait after stroke.

Multi-State Reliability Assessment Model of Base-Load Cyber-Physical Energy Systems (CPES) during Flexible Operation Considering the Aging of Cyber Components

Cyber-Physical Energy Systems (CPESs) are energy systems which rely on cyber components for energy production, transmission and distribution control, and other functions. With the penetration of Renewable Energy Sources (RESs), CPESs are required to provide flexible operation (e.g., load-following, frequency regulation) to respond to any sudden imbalance of the power grid, due to the variability in power generation by RESs. This raises concerns on the reliability of CPESs traditionally used as base-load facilities, such as Nuclear Power Plants (NPPs), which were not designed for flexible operation, and more so, since traditionally only hardware components aging and stochastic failures have been considered for the reliability assessment, whereas the contribution of the degradation and aging of the cyber components of CPSs has been neglected. In this paper, we propose a multi-state model that integrates the hardware components stochastic failures with the aging of cyber components, and quantify the unreliability of CPES in load-following operations under normal/emergency conditions. To show the application of the reliability assessment model, we consider the case of the Control Rod System (CRS) of a NPP typically used for a base-load energy supply.

Three pitfalls of accountable healthcare rationing

A pandemic may cause a sudden imbalance between available medical resources and medical needs where fundamental care to a patient cannot be delivered. Inability to fulfil a professional commitment to...

Adaptive inertia emulation control for high‐speed flywheel energy storage systems

Low-inertia power systems suffer from a high rate of change of frequency (ROCOF) during a sudden imbalance in supply and demand. Inertia emulation techniques using storage systems, such as flywheel energy storage systems (FESSs), can help to reduce the ROCOF by rapidly providing the needed power to balance the grid. In this work, a new adaptive controller for inertia emulation using high-speed FESS is proposed. The controller inertia and damping coefficients vary using a combination of bang–bang control approaches and self-adaptive ones, to simultaneously improve both the ROCOF and the frequency nadir. The performance of the proposed adaptive controller has been initially validated and compared with several existing adaptive controllers by means of offline simulations, and then validated with experimental results. The proposed controller has been implemented on a real 60 kW high-speed FESS, and its performance has been evaluated by means of power hardware-in-the-loop (PHIL) testing of the FESS in realistic grid conditions. Both simulations and PHIL testing results confirm that the proposed inertia emulation control for the FESS outperforms several previously reported controllers, in terms of reducing the maximum ROCOF and improving the frequency nadir during large disturbances.

Evolution of Cochlear implant mapping and vestibular function in a pediatric case of Labyrinthitis

BackgroundVestibular symptoms such as vertigo and imbalance are known to occur in some cochlear implant patients during the immediate postoperative period; however, acute vertigo in implanted children occurring remotely from the postoperative period has not been previously well-described.Case presentationA three-year-old girl with a history of bilateral sequential cochlear implantation presented with acute labyrinthitis associated with sudden onset of vertigo, balance impairment, and decline in right cochlear implant function 2 years after her most recent implant surgery. We describe her audiological and vestibular testing results during both the acute phase and following medical management and recovery.ConclusionAcute labyrinthitis should be considered when sudden onset vertigo and/or imbalance presents in children with cochlear implants outside of the perioperative period. Such symptoms should prompt early assessment of cochlear implant function, so that the device can be reprogrammed accordingly.

Response of Aeroengine with Fusing Design Suffering FBO

The loss of fan blades in an aeroengine, or fan-blade out (FBO), is a type of accident that causes a sudden imbalance and large impact load, which leads to complex vibration of a system. To conduct a dynamic analysis of an aeroengine rotor system is an important requirement for relevant departments. The purpose of this paper is to study the dynamic response of a complex dual-rotor system suffering FBO events and the protective effect of the fusing structure on the system. The dynamic model of an aeroengine dual-rotor system is established, and the response of the rotor system is obtained by calculation and analysis. The rear support bearing of the fan has a high reaction force, which may lead to bearing failure. The mechanism of a fusing structure is analyzed, and the results show that the sudden imbalance will produce impact loads on the rotor, resulting in a sharp increase in the vibration amplitude and reaction force, and then, attenuation to steady state. The fusing structure can reduce the amplitude of steady-state rotor vibration and reaction force on the support bearings. However, the transient response of the rotor will increase because of the sudden change in support stiffness.

Assessment of the protective effect of KN-93 drug in systemic epilepsy disorders induced by pilocarpine in male rat.

Epileptic seizures occur as a consequence of a sudden imbalance between the stimuli and inhibitors within the network of cortical neurons in favor of the stimulus. One of the drugs that induce epilepsy is pilocarpine. Systemic injection of pilocarpine affects on muscarinic receptors. Increasing evidence has addressed the implication of KN-93 by blocking Ca2+ /calmodulin-dependent protein kinase II (CaMKII), suppressing oxidative stress and inflammation, and also reducing neuron decay. So, we aimed to evaluate the potential preventive effects of KN-93 in systemic epilepsy disorders induced by pilocarpine. In thisanimal study, male rats were divided into five groups including treatment group (KN-93 with the dose of 5 mM/10 µL dimethyl sulfoxide(DMSO) before inducing epilepsy by 380 mg/kg pilocarpine) KN-93 group (received 5 mM KN-93), control group, epilepsy group (received 380 mg/kg pilocarpine Intraperitoneal), and sham group (received 10 µLDMSO). Oxidative stress was assessed by measuring its indicators including the concentration of malondialdehyde (MDA), nitrite, glutathione (GSH), as well as the antioxidant activity of catalase. In addition, serum levels of proinflammatory mediators including tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were determined. Pretreatment with KN-93 significantly reduced oxidative stress index by reducing the concentration of MDA, nitrite, and increasing the level of GSH. In addition, low concentrations of TNF-α and IL-1β were observed in hippocampus supernatant of KN-93 pretreated ratsin comparison with the pilocarpine groups. Moreover, administration of KN-93 improved neuronal density and attenuated the seizure activity and behavior. Overall, our findings suggest that KN-93 can effectively suppress oxidative stress and inflammation. Furthermore, KN-93 is able to attenuate seizure behaviorsby preventing its effects on neuron loss, so, it is valuable for the treatment of epileptic seizures.

Prediction of transient vibration response of dual-rotor-blade-casing system with blade off

Fan blade off occurring in a running rotor of the turbofan engine dual-rotor system will cause a sudden unbalance and inertia asymmetry, which results in large impact load and consequently induces the rubbing between blade and casing. In order to reveal the transient dynamic response characteristics of actual aero-engine when fan blade off event occurs, the dynamic model of dual-rotor-blade-casing system is developed, in which the distribution characteristics of the stiffness and mass, the load transfer, and the coupling effects of dual-rotor and casing are included. Considering several excitations caused by blade off, the physical process and mechanical characteristics of the fan blade off event are described qualitatively. Considering that only the casing acceleration signal can be used for condition monitoring in actual aero-engine, the transient response including rotor vibration displacement and casing vibration acceleration during the instantaneous status are obtained. Due to the time-varying and highly nonlinear characteristics of vibration responses, frequency slice wavelet transform is employed to isolate the vibration signal features. The results show that the impact load induced by the sudden imbalance causes significant increase of vibration amplitude. The rubbing action between blade and rotor will impose constraint effects on the rotor, which decreases the transient vibration amplitude. The inertia asymmetry has a big impact on the transient response. The vibration characteristics of casing acceleration under blade off are similar to those of rotor displacement, while casing acceleration response attenuates to stable value faster and is more sensitive to high-frequency components of vibration.

Diagnosis and management of acute myocardial infarction: An overview

Acute myocardial infarction (AMI) occurs when there is acute disruption of coronary blood flow, resulting in a sudden imbalance between myocardial oxygen demand and supply, which causes ischemia and necrosis. AMI accounts for the highest mortality rate of approximately 15% worldwide. The acute complications of AMI, including cardiac arrhythmias, tolls almost 50% deaths, which may occur on the way to the hospital. The effective treatment modalities for AMI include antianginal medications and reperfusion with thrombolytics (tissue plasminogen activator) or percutaneous coronary intervention (PCI). PCI is the established and widely used reperfusion technique in the management of AMI as thrombolytics are contraindicated in many patients. PCI is superior to thrombolytics with a higher reperfusion rate of approximately 90%, shorter hospital stay, and lowering the mortality rate. The intervention performed within 90 min of hospital arrival improves the clinical outcomes significantly. In this article, major updates in diagnosis and treatment modalities of AMI have been summarized, mainly focusing on the efficacy of PCI in improving the clinical outcomes.

Study on Vibration Characteristics of Fan Shaft of Geared Turbofan Engine With Sudden Imbalance Caused by Blade Off

Based on the requirements of the dynamic design of geared turbofan (GTF) engines, the vibration characteristic of the fan shaft is investigated. The effect of sudden imbalance caused by blade off, the time-varying meshing stiffness, and meshing errors on the vibration characteristics is fully considered in the dynamic model. The improved Euler–Bernoulli beam element considering the effects of shear deformation is employed and a coupled relationship between the gear–shaft–bearing–casing is established. Under windmilling condition with a single blade completely lost, the vibration characteristics of the fan shaft of the turbofan engine with and without a gearbox system are compared. The effect of the gear system on the vibration of the fan shaft under different rotating speeds is examined. The results show that the orbit of the fan shaft center in the turbofan engine with the gearbox system exhibits a multifrequency whirling motion and has a stable limit cycle. Under windmilling condition, the meshing frequency and the modal frequency have multiple intersection points. The critical speed is dense and the peak value of the transient vibration of the GTF engine gearbox shows a wave rise with an increase in speed. The results of this study could provide a reference for the parameter design and optimization of GTF engines.

Patterns of the Rotor-over-Stator Rolling under Change in the Damping Components

As experimental studies show, the rubbing of the rotor against the structure usually excites harmonics of different frequencies. In high-frequency regions, the power of the vibration signal appears to be considerable. The rotor—supports—stator system is in an unstable equilibrium state during the contact interaction between the rotor and the stator. The forces exerted on the rotor facilitate the excitation of the asynchronous rolling and its damping. The forces have been determined that facilitate the excitation of the progressive and retrograde rotor precession. The consideration of these forces in the algorithm for modeling the rotor-over-stator rolling development allows investigation of the impact of the components of the above forces on the behavior of the rotor system. The initial excitation—disturbance of the normal operation—of the rotor and subsequent unsteady oscillations of it result from sudden imbalance in the second span. The results of numerical modeling of the rubbing in the second span and the rotor-over-stator rolling upon change in the damping components of secondary (gyroscopic) components b ij (i ≠ j) of the damping matrix are presented for the rotor on three bearing-supports considering the synergetic effect of the forces of various types exerted on the rotor. It is shown that change in one of the parameters of the excitation forces leads to ambiguity of the pattern (manifestation form) of the asynchronous rotor-over-stator rolling and proves the existence of more than one states towards which the rotor—supports—stator system tends. In addition to the rolling with a constant rotor—stator contact, oscillations of the rotor develop in the direction perpendicular to the common trajectory of the precession motion of the rotor’s center with transition to the vibro-impact motion mode. The oscillations of the rotor tend towards the symmetry center of the system (the stator bore center). The reason is the components of the stiffness and damping forces that act in the direction transverse to the rotor’s motion trajectory. Recommendations are given for eliminating dangerous consequences of the development of the asynchronous rolling fraught with great financial losses.

Anticonvulsant effect of Bacopa monnieri extracts on Catecholamine metabolism during PTZ-induced Epilepsy in different brain regions of Albino Rat

In the modern era, Epilepsy is one of the most prevalent serious neurological disorders, affecting 0.5 to 1.0% of the world’s population. Epileptic seizures are paroxysmal clinical events arising from neuronal hyper-excitability and hypersynchrony of the cerebral cortex, either locally (partial seizures) or diffusely in both hemispheres (generalized seizures). The agitated neuronal activity that occurs during a seizure is caused by a sudden imbalance between the inhibitory and excitatory signals in the brain with glutamate, ?-aminobutyric acid (GABA), noradrenaline, serotonin, and dopamine. Since long term usage of antiepileptic drugs cause high incidence of pharmacoresistence and untoward side effects, attention has been paid in recent years to screen bioactive compounds from natural medicinal plants for treatment of several neurological disorders including Epilepsy. Keeping in view of relative importance of natural medicinal plants, the present study is mainly focused to characterize the anti-convulsant effect of Bacopa monnieri (BM), an Indian herb which is being extensively used in Ayurvedic treatments related to neurological complications. The present study was designed to assess the neurotoxicity of PTZ on the metabolism of Biogenic amines (Nor-epinephrine, Epinephrine, Dopamine, Serotonin) in different brain regions (Cerebral cortex, Cerebellum, Pons medulla and Hippocampus) of rat and explore the possible antiepileptic effect of different extracts (Ethanol, n-Hexane, Chloroform, Ethyl acetate, n-Butanol and Aqueous extracts) of BM in comparison with Diazepam (DZ) (Reference control). PTZ-Induced epilepsy caused significant decrease in all the catecholamine levels in all brain regions. On par with Diazepam pretreatment, different extracts of BM except aqueous extract (AE) significantly increased the monoamine contents in all the regions of brain. Mono amine oxidase (MAO) activity levels showed elevation in different brain regions of rat during PTZ-induced epilepsy which was reversed in epileptic animals pretreated with different extracts except AE and DZ. These findings suggest that BM causes perceptible changes in the biogenic amine metabolism as one of the major facets of its anticonvulsant activity. Hence, BM extract can be effectively used in the treatment of Epilepsy and other related neurological disorders.

Alterations in the Glutamate metabolism and Aminotransferases (AAT, ALAT) during PTZ – induced Epilepsy: Protective role of Bacopa monnieri

Epilepsy, a common chronic neurological disorder characterized by repeated, spontaneous seizures, also known as seizure disorder. Seizure related neuronal injury has been assumed to be mediated by glutamate, the excitatory amino acid, in the central nervous system that causes a sudden imbalance between the inhibitory and excitatory signals in the brain with glutamate, γ-aminobutyric acid (GABA), noradrenaline, serotonin, and dopamine. Since long term usage of antiepileptic drugs cause high incidence of pharmacoresistence and untoward side effects, attention has been paid in recent years to screen bioactive compounds from natural medicinal plants for treatment of several neurological disorders including Epilepsy. Keeping in view of relative importance of natural medicinal plants, the present study is mainly focused to characterize the anti-convulsant effect of Bacopa monnieri (BM), an Indian herb which is being extensively used in Ayurvedic treatments related to neurological complications. The present study is designed to assess the neurotoxicity of Pentylene tetrazole (PTZ), an epileptic compounds, on the Glutamate metabolism and Amino transferases in different brain regions (Cerebral cortex, Cerebellum, Pons medulla and Hippocampus) of rat and to explore the possible antiepileptic effect of different extracts (Ethanol, n-Hexane, Chloroform, Ethyl acetate, n-Butanol and Aqueous extracts) of BM in comparison with Diazepam (DZ) (Reference control). The activities of glutamate dehydrogenase (GDH), glutamine synthetase (GS) and glutamine content were decreased in different regions of brain during PTZ induced epilepsy which were increased in epileptic rats pretreated with different extracts of Bacopa monnieri except EAE and AE. Glutaminase activity was increased in PTZ induced epilepsy and decreased on pretreatment with all the extracts of BM except AE. In addition aspartate (AAT) and alanine aminotransferase (ALAT) activity levels were increased during PTZ induced epilepsy when compared with normal control and levels were reversed on pretreatment with different extracts of BM. Recoveries of these parameters during antiepileptic treatment suggest that the bioactive factors present in the extracts offer neuroprotection by interrupting the pathological cascade of glutamatergic hyperexcitation that occurs during epileptogenesis.

Behavior Modeling and Auction Architecture of Networked Microgrids for Frequency Support

As intermittent generation profiles introduce more stress due to the sudden imbalance in supply and demand, power systems are becoming more dependent on online aggregated support of networked utility-independent private microgrids. During the aggregation process, microgrid operators’ preferences and bidding behaviors are priority. New aggregation approaches are required considering the individual behaviors of the networked and geographically dispersed independent microgrids. In this paper, we present a novel bidding behavior modeling and an auction architecture consisting of a central aggregator and networked microgrid agents. The bidding behavioral states of the microgrid agents are formalized as partially observable Markov processes for the belief updates and short-term policy determination in order to maximize the individual profit. A reverse auction model is adopted to enable competitive negotiations between the central aggregator and networked microgrid agents. The auction and aggregation processes were implemented in a power system control area along with an automatic generation control (AGC) scheme to contribute frequency control. The proposed AGC and auction mechanism were verified with an industrial multi-agent framework in a laboratory-based real-time application.

Vibration control of high-speed rotor supported by hybrid foil-magnetic bearing with sudden imbalance

A hybrid foil-magnetic bearing (HFMB) was successfully studied as a vibration isolator by introducing a sudden imbalance or an unexpected disturbance during turbine/rotor operation. This HFMB is used to achieve stability during transient vibration behavior. The HFMB consists of two oil-free bearing technologies: an active magnetic bearing (AMB) and air foil bearing (AFB). Using both technologies takes advantage of the strengths of each bearing while compensating for their inherent weaknesses. In addition, the HFMB has good dynamic characteristics, and the damping can be adjusted using the appropriate gain selection for the AMB controller. Based on these unique features, dynamic stability can be enhanced, even if a sudden imbalance occurs while the rotor is operating. In this study, a rigid rotor was operated at up to 12,000 rpm and tested using a control algorithm to reduce the sudden imbalance vibration amplitudes. The experiment was conducted under the situation that the mass dropped out at 6,000 rpm. In order to validate the stability performance of the HFMB with a sudden mass loss, the vibration response results for the AFB and HFMB were compared. When applying the HFMB, the asynchronous vibration was suppressed, and the 1x vibration results showed reductions of almost 30%. When the sudden mass loss occurred, the magnetic control force was remarkably effective at reducing the asynchronous vibration of the rotor supported by the HFMB. In conclusion, it was experimentally verified that using the HFMB made sudden imbalance vibration control possible during rotor operation with an air foil bearing. In this respect, the HFMB has the characteristics of high stiffness/damping, which prevent rubbing and suppress excessive vibration due to a sudden imbalance event.

Behavior Analysis of Controllable Electrorheology Fluid Plain Journal Bearings

Electrorheological (ER) lubricant is applied to a rigid rotor system supported by a hydrodynamic bearing that is subjected to a sudden imbalance and a dynamic periodic rotating load. The pressure of the ER film, which exhibits a Bingham flow, varies with the electrical field strength and depends on the yield shear stress and the thickness of the ER fluid film. The ER lubricant was found to offer a good load capacity relative to a Newtonian lubricant and its performance could be controlled to handle sudden dynamic loads. Increasing the magnitude of the electric field strength provides a greater load capacity within certain physical limitations and also reduces the magnitude of an unbalanced force due to unbalanced mass and vibration caused by vibration in the dynamically rotating load. These results could be applied to the control of a suddenly imbalanced system, such as one with rotor blades, or for reducing vibration in cyclic loading rotor systems, such as in internal combustion engines.