WorldWideScience

Sample records for suspension system based

  1. Four-Wheel Vehicle Suspension System

    Science.gov (United States)

    Bickler, Donald B.

    1990-01-01

    Four-wheel suspension system uses simple system of levers with no compliant components to provide three-point suspension of chassis of vehicle while maintaining four-point contact with uneven terrain. Provides stability against tipping of four-point rectangular base, without rocking contact to which rigid four-wheel frame susceptible. Similar to six-wheel suspension system described in "Articulated Suspension Without Springs" (NPO-17354).

  2. Functional Based Adaptive and Fuzzy Sliding Controller for Non-Autonomous Active Suspension System

    Science.gov (United States)

    Huang, Shiuh-Jer; Chen, Hung-Yi

    In this paper, an adaptive sliding controller is developed for controlling a vehicle active suspension system. The functional approximation technique is employed to substitute the unknown non-autonomous functions of the suspension system and release the model-based requirement of sliding mode control algorithm. In order to improve the control performance and reduce the implementation problem, a fuzzy strategy with online learning ability is added to compensate the functional approximation error. The update laws of the functional approximation coefficients and the fuzzy tuning parameters are derived from the Lyapunov theorem to guarantee the system stability. The proposed controller is implemented on a quarter-car hydraulic actuating active suspension system test-rig. The experimental results show that the proposed controller suppresses the oscillation amplitude of the suspension system effectively.

  3. Decoupling Suspension Controller Based on Magnetic Flux Feedback

    Directory of Open Access Journals (Sweden)

    Wenqing Zhang

    2013-01-01

    Full Text Available The suspension module control system model has been established based on MIMO (multiple input and multiple output state feedback linearization. We have completed decoupling between double suspension points, and the new decoupling method has been applied to CMS04 magnetic suspension vehicle in national mid-low-speed maglev experiment field of Tangshan city in China. Double suspension system model is very accurate for investigating stability property of maglev control system. When magnetic flux signal is taken back to the suspension control system, the suspension module’s antijamming capacity for resisting suspension load variety has been proved. Also, the external force interference has been enhanced. As a result, the robustness and stability properties of double-electromagnet suspension control system have been enhanced.

  4. Decoupling suspension controller based on magnetic flux feedback.

    Science.gov (United States)

    Zhang, Wenqing; Li, Jie; Zhang, Kun; Cui, Peng

    2013-01-01

    The suspension module control system model has been established based on MIMO (multiple input and multiple output) state feedback linearization. We have completed decoupling between double suspension points, and the new decoupling method has been applied to CMS04 magnetic suspension vehicle in national mid-low-speed maglev experiment field of Tangshan city in China. Double suspension system model is very accurate for investigating stability property of maglev control system. When magnetic flux signal is taken back to the suspension control system, the suspension module's antijamming capacity for resisting suspension load variety has been proved. Also, the external force interference has been enhanced. As a result, the robustness and stability properties of double-electromagnet suspension control system have been enhanced.

  5. Hydropneumatic suspension systems

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, Wolfgang

    2011-07-01

    Hydropneumatic suspensions systems combine the excellent properties of gas springs with the favourable damping properties of hydraulic fluids. The advantages of these systems are particularly appropriate for automotive applications, such as passenger cars, trucks and agricultural equipment. In this book, Dr. Bauer provides an extensive overview of hydropneumatic suspension systems. Starting with a comparison of different types of suspension systems, the author subsequently describes the theoretical background associated with spring and damping characteristics of hydropneumatic systems and furthermore explains the design of the most important system components. Additionally he gives an overview of level control systems and various special functions. Finally the technology is illustrated by design examples and the outlook for future hydropneumatic suspensions is discussed. (orig.)

  6. Development of A New Automotive Active Suspension System

    Science.gov (United States)

    Yousef Abdulhammed, Eng.; Eng. Hisham Elsherif, Dr, Prof.

    2017-12-01

    The main objective was to develop a smart new vehicle suspension system that minimizes the road irregularities impact on the driver, also to increase performance and stability of the vehicle at high speeds. The central idea is based on modifying the normal passive suspension system into a computer controller hydraulic actuated active suspension system simply by adding a new component such as a hydraulic cylinder on a normal passive system. The new suspension system is economical to be wildly used in consumer’s cars with low prices. The new added components was analytically tested and modeled according to different parameters. A new test rig was implemented to simulate a real quarter suspension system. The new suspension model was controlled by feedback controller according to the road conditions; the controller output controls the cylinder actuator to compensate the road oscillations and increases the vehicle stability for the passenger. Finally, to maximize the aerodynamics coefficients of the vehicle during high speeds by controlling the vehicle clearance level from the ground to achieve full stability, steering and fuel economy.

  7. Optimal Vibration Control for Tracked Vehicle Suspension Systems

    Directory of Open Access Journals (Sweden)

    Yan-Jun Liang

    2013-01-01

    Full Text Available Technique of optimal vibration control with exponential decay rate and simulation for vehicle active suspension systems is developed. Mechanical model and dynamic system for a class of tracked vehicle suspension vibration control is established and the corresponding system of state space form is described. In order to prolong the working life of suspension system and improve ride comfort, based on the active suspension vibration control devices and using optimal control approach, an optimal vibration controller with exponential decay rate is designed. Numerical simulations are carried out, and the control effects of the ordinary optimal controller and the proposed controller are compared. Numerical simulation results illustrate the effectiveness of the proposed technique.

  8. Experimental Evaluation of Mountain Bike Suspension Systems

    Directory of Open Access Journals (Sweden)

    J. Titlestad

    2003-01-01

    Full Text Available A significant distinction between competitive mountain bikes is whether they have a suspension system. Research studies indicate that a suspension system gives advantages, but it is difficult to quantify the benefits because they depend on so many variables, including the physiology and psychology of the cyclist, the roughness of the track and the design of the suspension system. A laboratory based test rig has been built that allows the number of variables in the system to be reduced and test conditions to be controlled. The test rig simulates regular impacts of the rear wheel with bumps in a rolling road. The physiological variables of oxygen consumption and heart rate were measured, together with speeds and forces at various points in the system. Physiological and mechanical test results both confirm a significant benefit in using a suspension system on the simulated rough track, with oxygen consumption reduced by around 30 % and power transmitted through the pedals reduced by 30 % to 60 %.

  9. Multiobjective Robust Design of the Double Wishbone Suspension System Based on Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Xianfu Cheng

    2014-01-01

    Full Text Available The performance of the suspension system is one of the most important factors in the vehicle design. For the double wishbone suspension system, the conventional deterministic optimization does not consider any deviations of design parameters, so design sensitivity analysis and robust optimization design are proposed. In this study, the design parameters of the robust optimization are the positions of the key points, and the random factors are the uncertainties in manufacturing. A simplified model of the double wishbone suspension is established by software ADAMS. The sensitivity analysis is utilized to determine main design variables. Then, the simulation experiment is arranged and the Latin hypercube design is adopted to find the initial points. The Kriging model is employed for fitting the mean and variance of the quality characteristics according to the simulation results. Further, a particle swarm optimization method based on simple PSO is applied and the tradeoff between the mean and deviation of performance is made to solve the robust optimization problem of the double wishbone suspension system.

  10. Multiobjective Robust Design of the Double Wishbone Suspension System Based on Particle Swarm Optimization

    Science.gov (United States)

    Lin, Yuqun

    2014-01-01

    The performance of the suspension system is one of the most important factors in the vehicle design. For the double wishbone suspension system, the conventional deterministic optimization does not consider any deviations of design parameters, so design sensitivity analysis and robust optimization design are proposed. In this study, the design parameters of the robust optimization are the positions of the key points, and the random factors are the uncertainties in manufacturing. A simplified model of the double wishbone suspension is established by software ADAMS. The sensitivity analysis is utilized to determine main design variables. Then, the simulation experiment is arranged and the Latin hypercube design is adopted to find the initial points. The Kriging model is employed for fitting the mean and variance of the quality characteristics according to the simulation results. Further, a particle swarm optimization method based on simple PSO is applied and the tradeoff between the mean and deviation of performance is made to solve the robust optimization problem of the double wishbone suspension system. PMID:24683334

  11. Multiobjective robust design of the double wishbone suspension system based on particle swarm optimization.

    Science.gov (United States)

    Cheng, Xianfu; Lin, Yuqun

    2014-01-01

    The performance of the suspension system is one of the most important factors in the vehicle design. For the double wishbone suspension system, the conventional deterministic optimization does not consider any deviations of design parameters, so design sensitivity analysis and robust optimization design are proposed. In this study, the design parameters of the robust optimization are the positions of the key points, and the random factors are the uncertainties in manufacturing. A simplified model of the double wishbone suspension is established by software ADAMS. The sensitivity analysis is utilized to determine main design variables. Then, the simulation experiment is arranged and the Latin hypercube design is adopted to find the initial points. The Kriging model is employed for fitting the mean and variance of the quality characteristics according to the simulation results. Further, a particle swarm optimization method based on simple PSO is applied and the tradeoff between the mean and deviation of performance is made to solve the robust optimization problem of the double wishbone suspension system.

  12. An efficient recursive least square-based condition monitoring approach for a rail vehicle suspension system

    Science.gov (United States)

    Liu, X. Y.; Alfi, S.; Bruni, S.

    2016-06-01

    A model-based condition monitoring strategy for the railway vehicle suspension is proposed in this paper. This approach is based on recursive least square (RLS) algorithm focusing on the deterministic 'input-output' model. RLS has Kalman filtering feature and is able to identify the unknown parameters from a noisy dynamic system by memorising the correlation properties of variables. The identification of suspension parameter is achieved by machine learning of the relationship between excitation and response in a vehicle dynamic system. A fault detection method for the vertical primary suspension is illustrated as an instance of this condition monitoring scheme. Simulation results from the rail vehicle dynamics software 'ADTreS' are utilised as 'virtual measurements' considering a trailer car of Italian ETR500 high-speed train. The field test data from an E464 locomotive are also employed to validate the feasibility of this strategy for the real application. Results of the parameter identification performed indicate that estimated suspension parameters are consistent or approximate with the reference values. These results provide the supporting evidence that this fault diagnosis technique is capable of paving the way for the future vehicle condition monitoring system.

  13. Nonlinear Robust Observer-Based Fault Detection for Networked Suspension Control System of Maglev Train

    Directory of Open Access Journals (Sweden)

    Yun Li

    2013-01-01

    Full Text Available A fault detection approach based on nonlinear robust observer is designed for the networked suspension control system of Maglev train with random induced time delay. First, considering random bounded time-delay and external disturbance, the nonlinear model of the networked suspension control system is established. Then, a nonlinear robust observer is designed using the input of the suspension gap. And the estimate error is proved to be bounded with arbitrary precision by adopting an appropriate parameter. When sensor faults happen, the residual between the real states and the observer outputs indicates which kind of sensor failures occurs. Finally, simulation results using the actual parameters of CMS-04 maglev train indicate that the proposed method is effective for maglev train.

  14. The Design and Simulation of the Modular Vehicle Air Suspension Height Control System Based on ECAS

    Directory of Open Access Journals (Sweden)

    Yang Peigang

    2014-02-01

    Full Text Available Based on ECAS, this paper intended to develop a modular air suspension height control system with WABCO4728800010 two-position three way solenoid valves and Free scale MC9S12D64 microprocessor as its core components. And a simulation test was conducted in MATLAB/Simulink environment. The air suspension height control strategy of this system was divided into four modules: start control module, dynamic adjustment module, manual adjustment module and errors adjustment module, which were controlled by module select switch. Simulation tests indicated that the air suspension height control strategy is featured by its logical control accuracy and debug convenience, and the modular design greatly reduced the system complexity and software development cycle and costs as well.

  15. 49 CFR 570.8 - Suspension systems.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Suspension systems. 570.8 Section 570.8 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY... Pounds or Less § 570.8 Suspension systems. (a) Suspension condition. Ball joint seals shall not be cut or...

  16. T-S Fuzzy Model Based Control Strategy for the Networked Suspension Control System of Maglev Train

    Directory of Open Access Journals (Sweden)

    Guang He

    2015-01-01

    Full Text Available The control problem for the networked suspension control system of maglev train with random induced time delay and packet dropouts is investigated. First, Takagi-Sugeno (T-S fuzzy models are utilized to represent the discrete-time nonlinear networked suspension control system, and the parameters uncertainties of the nonlinear model have also been taken into account. The controllers take the form of parallel distributed compensation. Then, a sufficient condition for the stability of the networked suspension control system is derived. Based on the criteria, the state feedback fuzzy controllers are obtained, and the controller gains can be computed by using MATLAB LMI Toolbox directly. Finally, both the numerical simulations and physical experiments on the full-scale single bogie of CMS-04 maglev train have been accomplished to demonstrate the effectiveness of this proposed method.

  17. 49 CFR 570.61 - Suspension system.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Suspension system. 570.61 Section 570.61... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION VEHICLE IN USE INSPECTION STANDARDS Vehicles With GVWR of More Than 10,000 Pounds § 570.61 Suspension system. (a) Suspension condition. Ball joint seals shall not be cut...

  18. A new variable stiffness suspension system: passive case

    Directory of Open Access Journals (Sweden)

    O. M. Anubi

    2013-02-01

    Full Text Available This paper presents the design, analysis, and experimental validation of the passive case of a variable stiffness suspension system. The central concept is based on a recently designed variable stiffness mechanism. It consists of a horizontal control strut and a vertical strut. The main idea is to vary the load transfer ratio by moving the location of the point of attachment of the vertical strut to the car body. This movement is controlled passively using the horizontal strut. The system is analyzed using an L2-gain analysis based on the concept of energy dissipation. The analyses, simulation, and experimental results show that the variable stiffness suspension achieves better performance than the constant stiffness counterpart. The performance criteria used are; ride comfort, characterized by the car body acceleration, suspension deflection, and road holding, characterized by tire deflection.

  19. Design and analysis of an intelligent controller for active geometry suspension systems

    Science.gov (United States)

    Goodarzi, Avesta; Oloomi, Ehsan; Esmailzadeh, Ebrahim

    2011-02-01

    An active geometry suspension (AGS) system is a device to optimise suspension-related factors such as toe angle and roll centre height by controlling vehicle's suspension geometry. The suspension geometry could be changed through control of suspension mounting point's position. In this paper, analysis and control of an AGS system is addressed. First, the effects of suspension geometry change on roll centre height and toe angle are studied. Then, based on an analytical approach, the improvement of the vehicle's stability and handling due to the control of suspension geometry is investigated. In the next section, an eight-degree-of-freedom handling model of a sport utility vehicle equipped with an AGS system is introduced. Finally, a self-tuning proportional-integral controller has been designed, using the fuzzy control theory, to control the actuator that changes the geometry of the suspension system. The simulation results show that an AGS system can improve the handling and stability of the vehicle.

  20. A Semiactive and Adaptive Hybrid Control System for a Tracked Vehicle Hydropneumatic Suspension Based on Disturbance Identification

    Directory of Open Access Journals (Sweden)

    Shousong Han

    2017-01-01

    Full Text Available The riding conditions for a high-speed tracked vehicle are quite complex. To enhance the adaptability of suspension systems to different riding conditions, a semiactive and self-adaptive hybrid control strategy based on disturbance velocity and frequency identification was proposed. A mathematical model of the semiactive, self-adaptive hybrid suspension control system, along with a performance evaluation function, was established. Based on a two-degree-of-freedom (DOF suspension system, the kinematic relations and frequency zero-crossing detection method were defined, and expressions for the disturbance velocity and disturbance frequency of the road were obtained. Optimal scheduling of the semiactive hybrid damping control gain (csky, cground, chybrid and self-adaptive control gain (cv under different disturbances were realized by exploiting the particle swarm multiobjective optimization algorithm. An experimental study using a carefully designed test rig was performed under a number of typical riding conditions of tracked vehicles, and the results showed that the proposed control strategy is capable of accurately recognizing different disturbances, shifting between control modes (semiactive/self-adaptive, and scheduling the damping control gain according to the disturbance identification outcomes; hence, the proposed strategy could achieve a good trade-off between ride comfort and ride safety and efficiently increase the overall performance of the suspension under various riding conditions.

  1. Model predictive control of an air suspension system with damping multi-mode switching damper based on hybrid model

    Science.gov (United States)

    Sun, Xiaoqiang; Yuan, Chaochun; Cai, Yingfeng; Wang, Shaohua; Chen, Long

    2017-09-01

    This paper presents the hybrid modeling and the model predictive control of an air suspension system with damping multi-mode switching damper. Unlike traditional damper with continuously adjustable damping, in this study, a new damper with four discrete damping modes is applied to vehicle semi-active air suspension. The new damper can achieve different damping modes by just controlling the on-off statuses of two solenoid valves, which makes its damping adjustment more efficient and more reliable. However, since the damping mode switching induces different modes of operation, the air suspension system with the new damper poses challenging hybrid control problem. To model both the continuous/discrete dynamics and the switching between different damping modes, the framework of mixed logical dynamical (MLD) systems is used to establish the system hybrid model. Based on the resulting hybrid dynamical model, the system control problem is recast as a model predictive control (MPC) problem, which allows us to optimize the switching sequences of the damping modes by taking into account the suspension performance requirements. Numerical simulations results demonstrate the efficacy of the proposed control method finally.

  2. Analysis of a front suspension system for UniART FSAE car using FEA

    Science.gov (United States)

    Zaidie, M. N. A.; Hashim, M. S. M.; Tasyrif, M.; Basha, M. H.; Ibrahim, I.; Kamaruddin, N. S.; Shahriman, A. B.

    2017-10-01

    In recent years, many research works from institutions that participated in Formula SAE had highlighted on suspension systems. The aim is to improve the system in term of performance and robustness. However, every suspension system for a racing car is tailored to the car itself. Thus, this paper proposes a new design for front suspension system for UniART FSAE car. The new design was than being compared to the previous suspension system for enhancement. The analysis covered in this paper based on several conditions such as braking, cornering and bumping condition and was carried out using finite element analysis. Each main component for the suspension system such as lower arm, upper arm and knuckle has been analysed in term of strength and performance. From the results, the proposed new design of the suspension system has improved in term of strength and performance compared to the previous suspension system.

  3. Preview based control of suspension systems for commercial vehicles

    NARCIS (Netherlands)

    Muijderman, J.H.E.A.; Kok, J.J.; Huisman, R.G.M.; Veldpaus, F.E.; van Heck, J.G.A.M.

    1999-01-01

    An active suspension with preview is developed for the rear axle of a commercial vehicle. The obtained improvements are promising and justify further investigation of the more feasible semi-active suspensions with preview. The inherent non-linearity of semi-active suspensions with switching shock

  4. Attractive and repulsive magnetic suspension systems overview

    Science.gov (United States)

    Cope, David B.; Fontana, Richard R.

    1992-01-01

    Magnetic suspension systems can be used in a wide variety of applications. The decision of whether to use an attractive or repulsive suspension system for a particular application is a fundamental one which must be made during the design process. As an aid to the designer, we compare and contrast attractive and repulsive magnetic suspension systems and indicate whether and under what conditions one or the other system is preferred.

  5. Introducing Dual Suspension System in Road Vehicles

    Directory of Open Access Journals (Sweden)

    Imtiaz Hussain

    2013-04-01

    Full Text Available The main objective of suspension system is to reduce the motions of the vehicle body with respect to road disturbances. The conventional suspension systems in road vehicles use passive elements such as springs and dampers to suppress the vibrations induced by the irregularities in the road. But these conventional suspension systems can suppress vibrations to a certain limit. This paper presents a novel idea to improve the ride quality of roads vehicles without compromising vehicle?s stability. The paper proposes the use of primary and secondary suspension to suppress the vibrations more effectively.

  6. 49 CFR 393.207 - Suspension systems.

    Science.gov (United States)

    2010-10-01

    ... braking system. The vehicle shall be level (not tilting to the left or right). Air leakage shall not be... 49 Transportation 5 2010-10-01 2010-10-01 false Suspension systems. 393.207 Section 393.207... NECESSARY FOR SAFE OPERATION Frames, Cab and Body Components, Wheels, Steering, and Suspension Systems § 393...

  7. Study on Dynamic Behaviour of Wishbone Suspension System

    International Nuclear Information System (INIS)

    Kamal, M; Rahman, M M

    2012-01-01

    This paper presents the characteristic model of the wishbone suspension system using the quarter car model approach. Suspension system in an automobile provides vehicle control and passenger comfort by providing isolation from road disturbances. This makes it essential that the detailed behavior of suspension should be known to optimize the performance. A kinetic study is performed using multi body system (MBS) analysis. The dirt road profile is considered as an applied loading. The spring constant, damping coefficient and sprung mass are studied on the performance of the suspension system. It can be observed that the spring constant is inversely related with time required to return to initial position and the amount of deformations. The damping ratio affects the suppression of spring oscillations, beyond a certain limit damping ration has the negligible effect. Sprung mass effected the equilibrium position of the suspension system with a small effect on its oscillation behavior. It is shown that the spring constant, damping ratio and sprung mass are significant parameters to design the suspension system. This study is essential for complete understanding of working of the suspension system and a future study with real geometries.

  8. 5 MJ flywheel based on bulk HTS magnetic suspension

    Science.gov (United States)

    Poltavets, V.; Kovalev, K.; Ilyasov, R.; Glazunov, A.; Maevsky, V.; Verzbitsky, L.; Akhmadyshev, V.; Shikov, A.

    2014-05-01

    Nowadays the flywheel energy storage systems (FES) are developed intensively as uninterruptible power supply (UPS) devices for on-land and transport (especially airborne) applications worldwide. This work is devoted to the FES with magnetic suspension on the base of bulk HTS YBCO elements and permanent magnets. The developed FES is intended to be used as UPS in Russian atomic industry in case of an emergency. For the successful design of the FES the following questions should be solved: design of the motor/generator, design of the rotor (flywheel), design of the bearing system, design of the control system and system of power load matching, design of the cooling system. The developed small-scale FES with the stored energy 0.5 MJ was used to solve these basic questions. The elaborated FES consists of the synchronous electric machine with permanent magnets, the solid flywheel with axial magnetic suspension on the base of YBCO bulks and permanent magnets, the system of control and power load matching, and the system of liquid nitrogen cooling. The results of theoretical modeling of different schematics of magnetic suspension and experimental investigations of the constructed FES are presented. The design of the future full-scale FES with the stored energy ~5 MJ and output power up to 100 kW is described. The test results of the flywheel rotor and HTS magnetic suspension of 5 MJ FES are presented. This work is done under support of Rosatom within the frames of Russian Project "Superconducting Industry"

  9. FxLMS Method for Suppressing In-Wheel Switched Reluctance Motor Vertical Force Based on Vehicle Active Suspension System

    Directory of Open Access Journals (Sweden)

    Yan-yang Wang

    2014-01-01

    Full Text Available The vibration of SRM obtains less attention for in-wheel motor applications according to the present research works. In this paper, the vertical component of SRM unbalanced radial force, which is named as SRM vertical force, is taken into account in suspension performance for in-wheel motor driven electric vehicles (IWM-EV. The analysis results suggest that SRM vertical force has a great effect on suspension performance. The direct cause for this phenomenon is that SRM vertical force is directly exerted on the wheel, which will result in great variation in tyre dynamic load and the tyre will easily jump off the ground. Furthermore, the frequency of SRM vertical force is broad which covers the suspension resonance frequencies. So it is easy to arouse suspension resonance and greatly damage suspension performance. Aiming at the new problem, FxLMS (filtered-X least mean square controller is proposed to improve suspension performance. The FxLMS controller is based on active suspension system which can generate the controllable force to suppress the vibration caused by SRM vertical force. The conclusion shows that it is effective to take advantage of active suspensions to reduce the effect of SRM vertical force on suspension performance.

  10. Analysis of Train Suspension System Using MR dampers

    Science.gov (United States)

    RamaSastry, DVA; Ramana, K. V.; Mohan Rao, N.; Siva Kumar, SVR; Priyanka, T. G. L.

    2016-09-01

    This paper deals with introducing MR dampers to the Train Suspension System for improving the ride comfort of the passengers. This type of suspension system comes under Semi-active suspension system which utilizes the properties of MR fluid to damp the vibrations. In case of high speed trains, the coach body is subjected to vibrations due to vertical displacement, yaw and pitch movements. When the body receives these disturbances from the ground,the transmission of vibrations to the passenger increases which affect the ride comfort. In this work, the equations of motion of suspension system are developed for both conventional passive system and semi-active system and are modelled in Matlab/Simulink and analysis has been carried out. The passive suspension system analysis shows that it is taking more time to damp the vibrations and at the same time the transmissibility of vibrations is more.Introducing MR dampers,vertical and angular displacements of the body are computed and compared. The results show that the introduction of MR dampers into the train suspension system improves ride comfort.

  11. Neural control of magnetic suspension systems

    Science.gov (United States)

    Gray, W. Steven

    1993-01-01

    The purpose of this research program is to design, build and test (in cooperation with NASA personnel from the NASA Langley Research Center) neural controllers for two different small air-gap magnetic suspension systems. The general objective of the program is to study neural network architectures for the purpose of control in an experimental setting and to demonstrate the feasibility of the concept. The specific objectives of the research program are: (1) to demonstrate through simulation and experimentation the feasibility of using neural controllers to stabilize a nonlinear magnetic suspension system; (2) to investigate through simulation and experimentation the performance of neural controllers designs under various types of parametric and nonparametric uncertainty; (3) to investigate through simulation and experimentation various types of neural architectures for real-time control with respect to performance and complexity; and (4) to benchmark in an experimental setting the performance of neural controllers against other types of existing linear and nonlinear compensator designs. To date, the first one-dimensional, small air-gap magnetic suspension system has been built, tested and delivered to the NASA Langley Research Center. The device is currently being stabilized with a digital linear phase-lead controller. The neural controller hardware is under construction. Two different neural network paradigms are under consideration, one based on hidden layer feedforward networks trained via back propagation and one based on using Gaussian radial basis functions trained by analytical methods related to stability conditions. Some advanced nonlinear control algorithms using feedback linearization and sliding mode control are in simulation studies.

  12. Introducing Dual Suspension System in Road Vehicles

    OpenAIRE

    Imtiaz Hussain; Jawaid Daudpoto; Ali Asghar Memon

    2013-01-01

    The main objective of suspension system is to reduce the motions of the vehicle body with respect to road disturbances. The conventional suspension systems in road vehicles use passive elements such as springs and dampers to suppress the vibrations induced by the irregularities in the road. But these conventional suspension systems can suppress vibrations to a certain limit. This paper presents a novel idea to improve the ride quality of roads vehicles without compromising vehicle?s stability...

  13. Nonlinear Predictive Sliding Mode Control for Active Suspension System

    Directory of Open Access Journals (Sweden)

    Dazhuang Wang

    2018-01-01

    Full Text Available An active suspension system is important in meeting the requirements of the ride comfort and handling stability for vehicles. In this work, a nonlinear model of active suspension system and a corresponding nonlinear robust predictive sliding mode control are established for the control problem of active suspension. Firstly, a seven-degree-of-freedom active suspension model is established considering the nonlinear effects of springs and dampers; and secondly, the dynamic model is expanded in the time domain, and the corresponding predictive sliding mode control is established. The uncertainties in the controller are approximated by the fuzzy logic system, and the adaptive controller reduces the approximation error to increase the robustness of the control system. Finally, the simulation results show that the ride comfort and handling stability performance of the active suspension system is better than that of the passive suspension system and the Skyhook active suspension. Thus, the system can obviously improve the shock absorption performance of vehicles.

  14. Development of an Air Pneumatic Suspension System for Transtibial Prostheses

    Directory of Open Access Journals (Sweden)

    Gholamhossein Pirouzi

    2014-09-01

    Full Text Available The suspension system and socket fitting of artificial limbs have major roles and vital effects on the comfort, mobility, and satisfaction of amputees. This paper introduces a new pneumatic suspension system that overcomes the drawbacks of current suspension systems in donning and doffing, change in volume during daily activities, and pressure distribution in the socket-stump interface. An air pneumatic suspension system (APSS for total-contact sockets was designed and developed. Pistoning and pressure distribution in the socket-stump interface were tested for the new APSS. More than 95% of the area between each prosthetic socket and liner was measured using a Tekscan F-Scan pressure measurement which has developed matrix-based pressure sensing systems. The variance in pressure around the stump was 8.76 kPa. APSS exhibits less pressure concentration around the stump, improved pressure distribution, easy donning and doffing, adjustability to remain fitted to the socket during daily activities, and more adaptability to the changes in stump volume. The volume changes were adjusted by utility of air pressure sensor. The vertical displacement point and reliability of suspension were assessed using a photographic method. The optimum pressure in every level of loading weight was 55 kPa, and the maximum displacement was 6 mm when 90 N of weight was loaded.

  15. Intelligent systems of the vehicles’ suspension

    Science.gov (United States)

    Yurlin, D.

    2018-02-01

    The article is devoted to the current condition of car’s active suspension system. It presents the tendencies in development of the active systems of suspension system, adjustable elements incorporated in them and the companies succeeded in designing such systems. It also mirrors the problem of impact of active systems on car’s safety and their importance for the driver. Advantages and disadvantages of the most common types of active elements are being described, analyzed and compared. The author concludes about the perspectives of these systems’ development.

  16. An isotropic suspension system for a biaxial accelerometer using electroplated thick metal with a HAR SU-8 mold

    International Nuclear Information System (INIS)

    Lee, Jin Seung; Lee, Seung S

    2008-01-01

    In this paper, a novel approach is developed to design an isotropic suspension system using thick metal freestanding micro-structures combining bulk micro-machining with electroplating based on a HAR SU-8 mold. An omega-shape isotropic suspension system composed of circular curved beams that have free switching of imaginary boundary conditions is proposed. This novel isotropic suspension design is not affected by geometric dimensional parameters and always achieves matching stiffness along the principle axes of elasticity. Using the finite element method, the isotropic suspension system was compared with an S-shaped meandering suspension system. In order to realize the suggested isotropic suspension system, a cost-effective fabrication process using electroplating with the SU-8 mold was developed to avoid expensive equipment and materials such as deep reactive-ion etching (DRIE) or a silicon-on-insulator (SOI) wafer. The fabricated isotropic suspension system was verified by electromagnetic actuation experiments. Finally, a biaxial accelerometer with isotropic suspension system was realized and tested using a vibration generator system. The proposed isotropic suspension system and the modified surface micro-machining technique based on electroplating with an SU-8 mold can contribute towards minimizing the system size, simplifying the system configuration, reducing the system price of and facilitating mass production of various types of low-cost sensors and actuators

  17. Time response analysis in suspension system design of a high-speed car

    Science.gov (United States)

    Pagwiwoko, Cosmas Pandit

    2010-03-01

    A land speed record vehicle is designed to run on a flat surface like salt lake where the wheels are normally made from solid metal with a special suspension system. The suspension is designed to provide a stable platform to keep the wheel treads on tract, to insulate the car and the driver from the surface irregularities and to take part of good handling properties. The surface condition of the lake beds is basically flat without undulations but with inconsistent surface textures and ridges. Spring with nonlinear rate is used with the reason that the resistance builds up roughly proportional to the aerodynamic download for keeping the height more nearly constant. The objective of the work is to produce an efficient method for assisting the design of suspension system. At the initial step, the stiffness and the damping constants are determined based on RMS optimization by following the optimization strategy i.e. to minimize the absolute acceleration respect to the relative displacement of the suspension. Power bond graph technique is then used to model the nonlinearity of the components i.e. spring and dashpot of the suspension system. This technique also enables to incorporate the interactions of dynamic response of the vehicle's body with aerodynamic flow as a result of the base excitation of the ground to the wheels. The simulation is conducted on the platform of Simulink-MATLAB and the interactions amongst the components within the system are observed in time domain to evaluate the effectiveness of the suspension.

  18. Analysis of the Kinematics and Compliance of a Passive Suspension System using Adams Car

    Directory of Open Access Journals (Sweden)

    N. Ikhsan

    2015-06-01

    Full Text Available The experimental approach is usually used as the way to develop or modify a suspension system to obtain maximum ride comfort and handling characteristics. This approach is a time-consuming process, costly, and may not guarantee the optimum solution. Thus, to avoid this, a virtual vehicle suspension system is necessary. In this paper, a half-car body of an actual suspension system based on the PROTON WRM 44 P0-34 was modeled and simulated. In total, 10 components comprised each front McPherson strut and rear multilink suspension consisting of different joint types and a number of degrees of freedom. The model was developed by defining the location of the hard point or coordinate before specifying the component characteristics and joint type. The completed suspension model was simulated using the vertical parallel and vertical oppose movement test, the same tests conducted with the actual experimental parameter setup. The kinematics and compliance (K&C of the simulation is compared with the experimental data to verify the suspension model. The outcome from the simulation showed a verified virtual suspension system model with a very minimum percentage of error and different characteristics of the static performance of the suspension system when subjected to the test as explained further in the paper.

  19. Simulation Research on Vehicle Active Suspension Controller Based on G1 Method

    Science.gov (United States)

    Li, Gen; Li, Hang; Zhang, Shuaiyang; Luo, Qiuhui

    2017-09-01

    Based on the order relation analysis method (G1 method), the optimal linear controller of vehicle active suspension is designed. The system of the main and passive suspension of the single wheel vehicle is modeled and the system input signal model is determined. Secondly, the system motion state space equation is established by the kinetic knowledge and the optimal linear controller design is completed with the optimal control theory. The weighting coefficient of the performance index coefficients of the main passive suspension is determined by the relational analysis method. Finally, the model is simulated in Simulink. The simulation results show that: the optimal weight value is determined by using the sequence relation analysis method under the condition of given road conditions, and the vehicle acceleration, suspension stroke and tire motion displacement are optimized to improve the comprehensive performance of the vehicle, and the active control is controlled within the requirements.

  20. System and technique for ultrasonic characterization of settling suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Greenwood, Margaret S [Richland, WA; Panetta, Paul D [Richland, WA; Bamberger, Judith A [Richland, WA; Pappas, Richard A [Richland, WA

    2006-11-28

    A system for determining properties of settling suspensions includes a settling container, a mixer, and devices for ultrasonic interrogation transverse to the settling direction. A computer system controls operation of the mixer and the interrogation devices and records the response to the interrogating as a function of settling time, which is then used to determine suspension properties. Attenuation versus settling time for dilute suspensions, such as dilute wood pulp suspension, exhibits a peak at different settling times for suspensions having different properties, and the location of this peak is used as one mechanism for characterizing suspensions. Alternatively or in addition, a plurality of ultrasound receivers are arranged at different angles to a common transmitter to receive scattering responses at a variety of angles during particle settling. Angular differences in scattering as a function of settling time are also used to characterize the suspension.

  1. Design and experiment study of a semi-active energy-regenerative suspension system

    International Nuclear Information System (INIS)

    Shi, Dehua; Chen, Long; Wang, Ruochen; Jiang, Haobin; Shen, Yujie

    2015-01-01

    A new kind of semi-active energy-regenerative suspension system is proposed to recover suspension vibration energy, as well as to reduce the suspension cost and demands for the motor-rated capacity. The system consists of an energy-regenerative damper and a DC-DC converter-based energy-regenerative circuit. The energy-regenerative damper is composed of an electromagnetic linear motor and an adjustable shock absorber with three regulating levels. The linear motor just works as the generator to harvest the suspension vibration energy. The circuit can be used to improve the system’s energy-regenerative performance and to continuously regulate the motor’s electromagnetic damping force. Therefore, although the motor works as a generator and damps the isolation without an external power source, the motor damping force is controllable. The damping characteristics of the system are studied based on a two degrees of freedom vehicle vibration model. By further analyzing the circuit operation characteristics under different working modes, the double-loop controller is designed to track the desired damping force. The external-loop is a fuzzy controller that offers the desired equivalent damping. The inner-loop controller, on one hand, is used to generate the pulse number and the frequency to control the angle and the rotational speed of the step motor; on the other hand, the inner-loop is used to offer the duty cycle of the energy-regenerative circuit. Simulations and experiments are conducted to validate such a new suspension system. The results show that the semi-active energy-regenerative suspension can improve vehicle ride comfort with the controllable damping characteristics of the linear motor. Meanwhile, it also ensures energy regeneration. (paper)

  2. Decoupling Control Design for the Module Suspension Control System in Maglev Train

    Directory of Open Access Journals (Sweden)

    Guang He

    2015-01-01

    Full Text Available An engineering oriented decoupling control method for the module suspension system is proposed to solve the coupling issues of the two levitation units of the module in magnetic levitation (maglev train. According to the format of the system transfer matrix, a modified adjoint transfer matrix based decoupler is designed. Then, a compensated controller is obtained in the light of a desired close loop system performance. Optimization between the performance index and robustness index is also carried out to determine the controller parameters. However, due to the high orders and complexity of the obtained resultant controller, model reduction method is adopted to get a simplified controller with PID structure. Considering the modeling errors of the module suspension system as the uncertainties, experiments have been performed to obtain the weighting function of the system uncertainties. By using this, the robust stability of the decoupled module suspension control system is checked. Finally, the effectiveness of the proposed decoupling design method is validated by simulations and physical experiments. The results illustrate that the presented decoupling design can result in a satisfactory decoupling and better dynamic performance, especially promoting the reliability of the suspension control system in practical engineering application.

  3. Solution or suspension - Does it matter for lipid based systems?

    DEFF Research Database (Denmark)

    Larsen, A T; Holm, R; Müllertz, A

    2017-01-01

    In this study, the potential of co-administering an aqueous suspension with a placebo lipid vehicle, i.e. chase dosing, was investigated in rats relative to the aqueous suspension alone or a solution of the drug in the lipid vehicle. The lipid investigated in the present study was Labrafil M2125CS...... and three evaluated poorly soluble model compounds, danazol, cinnarizine and halofantrine. For cinnarizine and danazol the oral bioavailability in rats after chase dosing or dosing the compound dissolved in Labrafil M21515CS was similar and significantly higher than for the aqueous suspension....... For halofantrine the chase dosed group had a tendency towards a low bioavailability relative to the Labrafil M2125CS solution, but still a significant higher bioavailability relative to the aqueous suspension. This could be due to factors such as a slower dissolution rate in the intestinal phase of halofantrine...

  4. Design of a suspension system and determining suspension parameters of a medium downforce small Formula type car

    Directory of Open Access Journals (Sweden)

    Biswal Sadjyot

    2017-01-01

    Full Text Available The focus of the paper is on designing a suspension system for a medium downforce small Formula type race car. The paper not only focusses on step by step design for a double wishbone type suspension but will also show the use and role of kinematics software in determining the optimized suspension of the car. The paper will also focus on the use of tire data in determining suspension parameters and the design of the double wishbone suspension. Various parameters, their design importance and the process to optimize them according to suspension design goals will be covered. The easiest and best ways to change the suspension parameters to get the best results will also be covered.

  5. A universal suspension test rig for electrohydraulic active and passive automotive suspension system

    Directory of Open Access Journals (Sweden)

    Mahmoud Omar

    2017-12-01

    Full Text Available A fully active electro-hydraulic and passive automotive quarter car suspensions with their experimental test-rigs are designed and implemented. Investigation of the active performance compared against the passive is performed experimentally and numerically utilizing SIMULINK's Simscape library. Both systems are modeled as single-degree-of-freedom in order to simplify the validation process. Economic considerations were considered during the rig's implementation. The rig consists of two identical platforms fixed side by side allowing testing two independent suspensions simultaneously. Position sensors for sprung and unsprung masses on both platforms are installed. The road input is introduced by a cam and a roller follower mechanism driven by 1.12 kW single phase induction motor with speed reduction assembly. The active hydraulic cylinder was the most viable choice due to its high power-to-weight ratio. The active control is of the proportional-integral-differential (PID type. Though this technique is quite simple and not new, yet the emphasis of this paper is the engineering, design and implementation of the experimental setup and controller. A successful validation process is performed. Ride comfort significantly improved with active suspension, as shown by the results; 24.8% sprung mass vibration attenuation is achieved. The details of the developed system with the analytical and experimental results are presented. Keywords: Active suspension, Passive suspension, Servo, Hydraulic, Control, PID

  6. Ride performance of a high speed rail vehicle using controlled semi active suspension system

    Science.gov (United States)

    Sharma, Sunil Kumar; Kumar, Anil

    2017-05-01

    The rail-wheel interaction in a rail vehicle running at high speed results in large amplitude vibration of carbody that deteriorates the ride comfort of travellers. The role of suspension system is crucial to provide an acceptable level of ride performance. In this context, an existing rail vehicle is modelled in vertical, pitch and roll motions of carbody and bogies. Additionally, nonlinear stiffness and damping parameters of passive suspension system are defined based on experimental data. In the secondary vertical suspension system, a magneto-rheological (MR) damper is included to improve the ride quality and comfort. The parameters of MR damper depend on the current, amplitude and frequency of excitations. At different running speeds, three semi-active suspension strategies with MR damper are analysed for periodic track irregularity and the resulting performance indices are juxtaposed with the nonlinear passive suspension system. The disturbance rejection and force tracking damper controller algorithms are applied to control the desired force of MR damper. This study reveals that the vertical vibrations of a vehicle can be reduced significantly by using the proposed semi-active suspension strategies. Moreover, it naturally results in improved ride quality and passenger’s comfort in comparison to the existing passive system.

  7. 15 CFR 2011.207 - Suspension of the certificate system.

    Science.gov (United States)

    2010-01-01

    ..., SYRUPS AND MOLASSES Specialty Sugar § 2011.207 Suspension of the certificate system. (a) Suspension. The.... Notice of such suspension and the effective date thereof shall be published in the Federal Register. (b... such reinstatement and the effective date thereof shall be published in the Federal Register. (c...

  8. Suspension system vibration analysis with regard to variable type ability to smooth road irregularities

    Science.gov (United States)

    Rykov, S. P.; Rykova, O. A.; Koval, V. S.; Makhno, D. E.; Fedotov, K. V.

    2018-03-01

    The paper aims to analyze vibrations of the dynamic system equivalent of the suspension system with regard to tyre ability to smooth road irregularities. The research is based on static dynamics for linear systems of automated control, methods of correlation, spectral and numerical analysis. Input of new data on the smoothing effect of the pneumatic tyre reflecting changes of a contact area between the wheel and road under vibrations of the suspension makes the system non-linear which requires using numerical analysis methods. Taking into account the variable smoothing ability of the tyre when calculating suspension vibrations, one can approximate calculation and experimental results and improve the constant smoothing ability of the tyre.

  9. Muscle Activation during Push-Ups with Different Suspension Training Systems

    Directory of Open Access Journals (Sweden)

    Joaquin Calatayud, Sebastien Borreani, Juan C. Colado, Fernando F Martín, Michael E. Rogers

    2014-09-01

    Full Text Available The purpose of this study was to analyze upper extremity and core muscle activation when performing push-ups with different suspension devices. Young fit male university students (n = 29 performed 3 push-ups each with 4 different suspension systems. Push-up speed was controlled using a metronome and testing order was randomized. Average amplitude of the electromyographic root mean square of Triceps Brachii, Upper Trapezius, Anterior Deltoid, Clavicular Pectoralis, Rectus Abdominis, Rectus Femoris, and Lumbar Erector Spinae was recorded. Electromyographic signals were normalized to the maximum voluntary isometric contraction (MVIC. Electromyographic data were analyzed with repeated-measures analysis of variance with a Bonferroni post hoc. Based upon global arithmetic mean of all muscles analyzed, the suspended push-up with a pulley system provided the greatest activity (37.76% of MVIC; p < 0.001. Individually, the suspended push-up with a pulley system also provided the greatest triceps brachii, upper trapezius, rectus femoris and erector lumbar spinae muscle activation. In contrast, more stable conditions seem more appropriate for pectoralis major and anterior deltoid muscles. Independent of the type of design, all suspension systems were especially effective training tools for reaching high levels of rectus abdominis activation.

  10. Online Adaptive Optimal Control of Vehicle Active Suspension Systems Using Single-Network Approximate Dynamic Programming

    Directory of Open Access Journals (Sweden)

    Zhi-Jun Fu

    2017-01-01

    Full Text Available In view of the performance requirements (e.g., ride comfort, road holding, and suspension space limitation for vehicle suspension systems, this paper proposes an adaptive optimal control method for quarter-car active suspension system by using the approximate dynamic programming approach (ADP. Online optimal control law is obtained by using a single adaptive critic NN to approximate the solution of the Hamilton-Jacobi-Bellman (HJB equation. Stability of the closed-loop system is proved by Lyapunov theory. Compared with the classic linear quadratic regulator (LQR approach, the proposed ADP-based adaptive optimal control method demonstrates improved performance in the presence of parametric uncertainties (e.g., sprung mass and unknown road displacement. Numerical simulation results of a sedan suspension system are presented to verify the effectiveness of the proposed control strategy.

  11. Theoretical and FEM analysis of suspension and propulsion system with HTS hybrid electromagnets in an EMS Maglev model

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Y.D., E-mail: ydchung@suwon.ac.kr [Department of Electrical Engineering, Suwon University, Bongdang Eup, Hwaseong Si 445-743 (Korea, Republic of); Lee, C.Y. [Korea Railroad Research Institute, Woram Dong, Uiwang Si 437-757 (Korea, Republic of); Jang, J.Y. [Department of Electrical Engineering, Ansan College of Technology, Choji-Dong, Ansan Si 425-792 (Korea, Republic of); Yoon, Y.S. [Department of Electrical and Electronic Engineering, Yonsei University, Sinchon-dong, Seoul 120-749 (Korea, Republic of); Ko, T.K. [Department of Electrical Engineering, Ansan College of Technology, Choji-Dong, Ansan Si 425-792 (Korea, Republic of)

    2011-11-15

    We examine levitation and propulsion forces of the proto-type maglev vehicle system based on 3D FEM. The levitation force increases over 15% due to AC current of the guideway. The levitation force by HTS electromagnet (EM) and AC current is larger over 30% than that of only HTS EM. We have been constructed a proto-type electromagnetic suspension (EMS) based maglev vehicle system. The maglev concept utilizes magnetic forces for noncontact suspension, guidance and propulsion. The suspension system with high temperature superconducting (HTS) hybrid electromagnet (EM) is composed of HTS coils and normal coils, which consume little power to keep large suspension gap. The magnetic forces realize to guide the vehicle, propel the vehicle along the guide-way and assist in braking action. The proto-type EMS-based Maglev model is designed to keep the suspension gap of 20 mm. This paper presents the theoretical analysis of the maglev vehicle based on the EMS model to obtain the designing parameters for levitation and propulsion forces. The magnetic field distributions of the electromagnetic forces with hybrid EM and propulsion stator coils are analyzed based on three dimension (3D) finite element method (FEM) analysis. From the simulation results, appropriately design parameters of the suspension, guidance and propulsion were obtained.

  12. Theoretical and FEM analysis of suspension and propulsion system with HTS hybrid electromagnets in an EMS Maglev model

    International Nuclear Information System (INIS)

    Chung, Y.D.; Lee, C.Y.; Jang, J.Y.; Yoon, Y.S.; Ko, T.K.

    2011-01-01

    We examine levitation and propulsion forces of the proto-type maglev vehicle system based on 3D FEM. The levitation force increases over 15% due to AC current of the guideway. The levitation force by HTS electromagnet (EM) and AC current is larger over 30% than that of only HTS EM. We have been constructed a proto-type electromagnetic suspension (EMS) based maglev vehicle system. The maglev concept utilizes magnetic forces for noncontact suspension, guidance and propulsion. The suspension system with high temperature superconducting (HTS) hybrid electromagnet (EM) is composed of HTS coils and normal coils, which consume little power to keep large suspension gap. The magnetic forces realize to guide the vehicle, propel the vehicle along the guide-way and assist in braking action. The proto-type EMS-based Maglev model is designed to keep the suspension gap of 20 mm. This paper presents the theoretical analysis of the maglev vehicle based on the EMS model to obtain the designing parameters for levitation and propulsion forces. The magnetic field distributions of the electromagnetic forces with hybrid EM and propulsion stator coils are analyzed based on three dimension (3D) finite element method (FEM) analysis. From the simulation results, appropriately design parameters of the suspension, guidance and propulsion were obtained.

  13. Differential Evolution-Based PID Control of Nonlinear Full-Car Electrohydraulic Suspensions

    Directory of Open Access Journals (Sweden)

    Jimoh O. Pedro

    2013-01-01

    Full Text Available This paper presents a differential-evolution- (DE- optimized, independent multiloop proportional-integral-derivative (PID controller design for full-car nonlinear, electrohydraulic suspension systems. The multiloop PID control stabilises the actuator via force feedback and also improves the system performance. Controller gains are computed using manual tuning and through DE optimization to minimise a performance index, which addresses suspension travel, road holding, vehicle handling, ride comfort, and power consumption constraints. Simulation results showed superior performance of the DE-optimized PID-controlled active vehicle suspension system (AVSS over the manually tuned PID-controlled AVSS and the passive vehicle suspension system (PVSS.

  14. An efficient sensitivity analysis method for modified geometry of Macpherson suspension based on Pearson correlation coefficient

    Science.gov (United States)

    Shojaeefard, Mohammad Hasan; Khalkhali, Abolfazl; Yarmohammadisatri, Sadegh

    2017-06-01

    The main purpose of this paper is to propose a new method for designing Macpherson suspension, based on the Sobol indices in terms of Pearson correlation which determines the importance of each member on the behaviour of vehicle suspension. The formulation of dynamic analysis of Macpherson suspension system is developed using the suspension members as the modified links in order to achieve the desired kinematic behaviour. The mechanical system is replaced with an equivalent constrained links and then kinematic laws are utilised to obtain a new modified geometry of Macpherson suspension. The equivalent mechanism of Macpherson suspension increased the speed of analysis and reduced its complexity. The ADAMS/CAR software is utilised to simulate a full vehicle, Renault Logan car, in order to analyse the accuracy of modified geometry model. An experimental 4-poster test rig is considered for validating both ADAMS/CAR simulation and analytical geometry model. Pearson correlation coefficient is applied to analyse the sensitivity of each suspension member according to vehicle objective functions such as sprung mass acceleration, etc. Besides this matter, the estimation of Pearson correlation coefficient between variables is analysed in this method. It is understood that the Pearson correlation coefficient is an efficient method for analysing the vehicle suspension which leads to a better design of Macpherson suspension system.

  15. Fault Detection Based on Tracking Differentiator Applied on the Suspension System of Maglev Train

    Directory of Open Access Journals (Sweden)

    Hehong Zhang

    2015-01-01

    Full Text Available A fault detection method based on the optimized tracking differentiator is introduced. It is applied on the acceleration sensor of the suspension system of maglev train. It detects the fault of the acceleration sensor by comparing the acceleration integral signal with the speed signal obtained by the optimized tracking differentiator. This paper optimizes the control variable when the states locate within or beyond the two-step reachable region to improve the performance of the approximate linear discrete tracking differentiator. Fault-tolerant control has been conducted by feedback based on the speed signal acquired from the optimized tracking differentiator when the acceleration sensor fails. The simulation and experiment results show the practical usefulness of the presented method.

  16. Self-powered suspension criterion and energy regeneration implementation scheme of motor-driven active suspension

    Science.gov (United States)

    Yan, Shuai; Sun, Weichao

    2017-09-01

    Active suspension systems have advantages on mitigating the effects of vehicle vibration caused by road roughness, which are one of the most important component parts in influencing the performances of vehicles. However, high amount of energy consumption restricts the application of active suspension systems. From the point of energy saving, this paper presents a self-powered criterion of the active suspension system to judge whether a motor-driven suspension can be self-powered or not, and then a motor parameter condition is developed as a reference to design a self-powered suspension. An energy regeneration implementation scheme is subsequently proposed to make the active suspension which has the potential to be self-powered achieve energy-saving target in the real application. In this implementation scheme, operating electric circuits are designed based on different working status of the actuator and power source and it is realizable to accumulate energy from road vibration and supply energy to the actuator by switching corresponding electric circuits. To apply the self-powered suspension criterion and energy regeneration implementation scheme, an active suspension system is designed with a constrained H∞ controller and calculation results indicate that it has the capability to be self-powered. Simulation results show that the performances of the self-powered active suspension are nearly the same as those of the active suspension with an external energy source and can achieve energy regeneration at the same time.

  17. Design and test of a novel magnetic lead screw for active suspension system in a vehicle

    DEFF Research Database (Denmark)

    Berg, Nick Ilsø; Holm, Rasmus Koldborg; Rasmussen, Peter Omand

    2014-01-01

    . Furthermore the Magnetic Lead Screw is introduced and its benefits when used with an active suspension system are discussed. Based on a model of a quarter car, the design specifications for the MLS active suspension system are found, which leads to a design study. The design study investigates the relation...

  18. A Kinematic, Kevlar(registered) Suspension System for an ADR

    Science.gov (United States)

    Voellmer, George M.; Jackson, Michael L.; Shirron, Peter J.; Tuttle, James G.

    2003-01-01

    The High Resolution Airborne Wideband Camera (HAWC) and the Submillimeter And Far Infrared Experiment (SAFIRE) will use identical Adiabatic Demagnetization Refrigerators (ADR) to cool their bolometer detectors to 200mK and 100mK, respectively. In order to minimize thermal loads on the salt pill, a Kevlar@ suspension system is used to hold it in place. An innovative, kinematic suspension system is presented. The suspension system is unique in that it consists or two parts that can be assembled and tensioned offline, and later bolted onto the salt pill. The resulting assembly constrains each degree of freedom only once, yielding a kinematic, tensile structure.

  19. MEMS mass-spring-damper systems using an out-of-plane suspension scheme

    KAUST Repository

    Abdel Aziz, Ahmed Kamal Said; Sharaf, Abdel Hameed; Serry, Mohamed Yousef; Sedky, Sherif Salah

    2014-01-01

    MEMS mass-spring-damper systems (including MEMS gyroscopes and accelerometers) using an out-of-plane (or vertical) suspension scheme, wherein the suspensions are normal to the proof mass, are disclosed. Such out-of-plane suspension scheme helps such MEMS mass-spring-damper systems achieve inertial grade performance. Methods of fabricating out-of-plane suspensions in MEMS mass-spring-damper systems (including MEMS gyroscopes and accelerometers) are also disclosed.

  20. MEMS mass-spring-damper systems using an out-of-plane suspension scheme

    KAUST Repository

    Abdel Aziz, Ahmed Kamal Said

    2014-02-04

    MEMS mass-spring-damper systems (including MEMS gyroscopes and accelerometers) using an out-of-plane (or vertical) suspension scheme, wherein the suspensions are normal to the proof mass, are disclosed. Such out-of-plane suspension scheme helps such MEMS mass-spring-damper systems achieve inertial grade performance. Methods of fabricating out-of-plane suspensions in MEMS mass-spring-damper systems (including MEMS gyroscopes and accelerometers) are also disclosed.

  1. 15 CFR 2011.110 - Suspension of certificate system.

    Science.gov (United States)

    2010-01-01

    ..., SYRUPS AND MOLASSES Certificate of Quota Eligibility § 2011.110 Suspension of certificate system. (a... of such suspension and the effective date thereof shall be published in the Federal Register. (b... such reinstatement and the effective date thereof shall be published in the Federal Register. (c...

  2. Computation of magnetic suspension of maglev systems using dynamic circuit theory

    Science.gov (United States)

    He, J. L.; Rote, D. M.; Coffey, H. T.

    1992-01-01

    Dynamic circuit theory is applied to several magnetic suspensions associated with maglev systems. These suspension systems are the loop-shaped coil guideway, the figure-eight-shaped null-flux coil guideway, and the continuous sheet guideway. Mathematical models, which can be used for the development of computer codes, are provided for each of these suspension systems. The differences and similarities of the models in using dynamic circuit theory are discussed in the paper. The paper emphasizes the transient and dynamic analysis and computer simulation of maglev systems. In general, the method discussed here can be applied to many electrodynamic suspension system design concepts. It is also suited for the computation of the performance of maglev propulsion systems. Numerical examples are presented in the paper.

  3. Progress towards extreme attitude testing with Magnetic Suspension and Balance Systems

    Science.gov (United States)

    Britcher, Colin P.; Parker, David H.

    1988-01-01

    Progress is reported in a research effort aimed towards demonstration of the feasibility of suspension and aerodynamic testing of models at high angles of attack in wind tunnel Magnetic Suspension and Balance Systems. Extensive modifications, described in this paper, have been made to the Southampton University suspension system in order to facilitate this work. They include revision of electromagnet configuration, installation of all-new position sensors and expansion of control system programs. An angle of attack range of 0 to 90 deg is expected for axisymmetric models. To date, suspension up to 80 deg angle of attack has been achieved.

  4. Effect of the crone suspension control system on braking

    Energy Technology Data Exchange (ETDEWEB)

    Moreau, X.; Oustaloup, A. [Bordeaux-1 Univ., Talence (France). Lab. d' Automatique et de Productique; Nouillant, C. [Bordeaux-1 Univ., Talence (France). Lab. d' Automatique et de Productique]|[DRIA-PSA Peugeot Citroen, Velizy - Villacoublay (France)

    2001-07-01

    Semi-active or active suspensions not only increase driving comfort, but also permit the control system to be switched over if required in order to improve the transmission of forces at the points of contact between tire and road surface by minimizing the dynamic wheel loads. It may also be possible to use these systems to control wheel load distribution and, thus, influence braking or steering performance by changing the distribution of normal forces between the front and rear axles. This article examines the effect of the CRONE suspension control system on braking. The central idea is to use continuously variable dampers and fast load levelling devices to distribute the normal forces of tire between the front and rear axles. The basis principle is explained using known dynamic properties of active suspension, vehicles and tires. The effect of active suspension on vehicle response during braking is then evaluated using computer simulations from a two-wheel vehicle model. (orig.)

  5. Hierarchical Control Strategy for Active Hydropneumatic Suspension Vehicles Based on Genetic Algorithms

    Directory of Open Access Journals (Sweden)

    Jinzhi Feng

    2015-02-01

    Full Text Available A new hierarchical control strategy for active hydropneumatic suspension systems is proposed. This strategy considers the dynamic characteristics of the actuator. The top hierarchy controller uses a combined control scheme: a genetic algorithm- (GA- based self-tuning proportional-integral-derivative controller and a fuzzy logic controller. For practical implementations of the proposed control scheme, a GA-based self-learning process is initiated only when the defined performance index of vehicle dynamics exceeds a certain debounce time threshold. The designed control algorithm is implemented on a virtual prototype and cosimulations are performed with different road disturbance inputs. Cosimulation results show that the active hydropneumatic suspension system designed in this study significantly improves riding comfort characteristics of vehicles. The robustness and adaptability of the proposed controller are also examined when the control system is subjected to extremely rough road conditions.

  6. Measurements on an electromagnetic active suspension system for automotive applications

    NARCIS (Netherlands)

    Gysen, B.L.J.; Paulides, J.J.H.; Lomonova, E.A.; Encica, L.; Gysen, B.L.J.; Jansen, J.W.; Krop, D.C.J.

    2008-01-01

    Abstract—This paper describes the specifications for active suspension systems and provides an electromagnetic solution. Electromagnetic actuation and preliminary control strategies are investigated in order to achieve a suspension system with the ability to absorb road irregularities and perform

  7. Adaptive tracking control for active suspension systems with non-ideal actuators

    Science.gov (United States)

    Pan, Huihui; Sun, Weichao; Jing, Xingjian; Gao, Huijun; Yao, Jianyong

    2017-07-01

    As a critical component of transportation vehicles, active suspension systems are instrumental in the improvement of ride comfort and maneuverability. However, practical active suspensions commonly suffer from parameter uncertainties (e.g., the variations of payload mass and suspension component parameters), external disturbances and especially the unknown non-ideal actuators (i.e., dead-zone and hysteresis nonlinearities), which always significantly deteriorate the control performance in practice. To overcome these issues, this paper synthesizes an adaptive tracking control strategy for vehicle suspension systems to achieve suspension performance improvements. The proposed control algorithm is formulated by developing a unified framework of non-ideal actuators rather than a separate way, which is a simple yet effective approach to remove the unexpected nonlinear effects. From the perspective of practical implementation, the advantages of the presented controller for active suspensions include that the assumptions on the measurable actuator outputs, the prior knowledge of nonlinear actuator parameters and the uncertain parameters within a known compact set are not required. Furthermore, the stability of the closed-loop suspension system is theoretically guaranteed by rigorous mathematical analysis. Finally, the effectiveness of the presented adaptive control scheme is confirmed using comparative numerical simulation validations.

  8. Operational Modal Analysis and the Performance Assessment of Vehicle Suspension Systems

    Directory of Open Access Journals (Sweden)

    L. Soria

    2012-01-01

    Full Text Available Comfort, road holding and safety of passenger cars are mainly influenced by an appropriate design of suspension systems. Improvements of the dynamic behaviour can be achieved by implementing semi-active or active suspension systems. In these cases, the correct design of a well-performing suspension control strategy is of fundamental importance to obtain satisfying results. Operational Modal Analysis allows the experimental structural identification in those that are the real operating conditions: Moving from output-only data, leading to modal models linearised around the more interesting working points and, in the case of controlled systems, providing the needed information for the optimal design and verification of the controller performance. All these characters are needed for the experimental assessment of vehicle suspension systems. In the paper two suspension architectures are considered equipping the same car type. The former is a semi-active commercial system, the latter a novel prototypic active system. For the assessment of suspension performance, two different kinds of tests have been considered, proving ground tests on different road profiles and laboratory four poster rig tests. By OMA-processing the signals acquired in the different testing conditions and by comparing the results, it is shown how this tool can be effectively utilised to verify the operation and the performance of those systems, by only carrying out a simple, cost-effective road test.

  9. A novel magnetic lead screw active suspension system for vehicles

    DEFF Research Database (Denmark)

    Berg, Nick Ilsø; Holm, Rasmus Koldborg; Rasmussen, Peter Omand

    2014-01-01

    This paper encompasses a detailed study of the redesign of a novel Magnetic Lead Screw (MLS) active suspension system for possible regeneration of the energy dispatched in the suspension system and active control of vehicle body movement. The MLS converts a low speed high force linear motion...... of a translator into a high speed low torque rotational motion of a rotor through helically shaped magnets. The paper describes the drawback of the first MLS prototype v1.0 developed for active suspension system, which lead to a new design of the MLS prototype named v1.5. Furthermore the paper introduces detailed...

  10. Performance Testing of Suspension Plasma Sprayed Thermal Barrier Coatings Produced with Varied Suspension Parameters

    Directory of Open Access Journals (Sweden)

    Nicholas Curry

    2015-07-01

    Full Text Available Suspension plasma spraying has become an emerging technology for the production of thermal barrier coatings for the gas turbine industry. Presently, though commercial systems for coating production are available, coatings remain in the development stage. Suitable suspension parameters for coating production remain an outstanding question and the influence of suspension properties on the final coatings is not well known. For this study, a number of suspensions were produced with varied solid loadings, powder size distributions and solvents. Suspensions were sprayed onto superalloy substrates coated with high velocity air fuel (HVAF -sprayed bond coats. Plasma spray parameters were selected to generate columnar structures based on previous experiments and were maintained at constant to discover the influence of the suspension behavior on coating microstructures. Testing of the produced thermal barrier coating (TBC systems has included thermal cyclic fatigue testing and thermal conductivity analysis. Pore size distribution has been characterized by mercury infiltration porosimetry. Results show a strong influence of suspension viscosity and surface tension on the microstructure of the produced coatings.

  11. The Active Fractional Order Control for Maglev Suspension System

    Directory of Open Access Journals (Sweden)

    Peichang Yu

    2015-01-01

    Full Text Available Maglev suspension system is the core part of maglev train. In the practical application, the load uncertainties, inherent nonlinearity, and misalignment between sensors and actuators are the main issues that should be solved carefully. In order to design a suitable controller, the attention is paid to the fractional order controller. Firstly, the mathematical model of a single electromagnetic suspension unit is derived. Then, considering the limitation of the traditional PD controller adaptation, the fractional order controller is developed to obtain more excellent suspension specifications and robust performance. In reality, the nonlinearity affects the structure and the precision of the model after linearization, which will degrade the dynamic performance. So, a fractional order controller is addressed to eliminate the disturbance by adjusting the parameters which are added by the fractional order controller. Furthermore, the controller based on LQR is employed to compare with the fractional order controller. Finally, the performance of them is discussed by simulation. The results illustrated the validity of the fractional order controller.

  12. Analysis of Driving Safety Criteria Based on National Regulations for the Suspension Systems of NGVs

    Directory of Open Access Journals (Sweden)

    Ronald Mauricio Martinod

    2015-01-01

    Full Text Available The work analyses the technical evaluation process of the suspension system for vehicles that have been adapted to natural-gas-fuelled engines from power light-duty gasoline, and diesel vehicles; this evaluation is done through a mechanical review established by national regulations. The development of this analysis is focused on establishing the relationship between the natural-gas-fuelled equipment and the dynamic effect caused by the extra-weight, according to two measuring criteria that determine the safety and driving comfort, these are: (i tire-road adhesion index; and (ii tire excitation phase angle. The paper also proposes new elements that can be added to the current national regulations and that are currently applied to assess the suspension of natural gas vehicles, recorded using a test standard benchmark for the evaluation of the suspension.

  13. Fuzzy-Skyhook Control for Active Suspension Systems Applied to a Full Vehicle Model

    Directory of Open Access Journals (Sweden)

    Aref M.A. Soliman

    2012-04-01

    Full Text Available Nowadays, most modern vehicles are equipped with controlled suspension systems for improving the vehicle ride comfort. Therefore, this paper is concerned with a theoretical study for the ride comfort performance of the vehicle. The theoretical investigation includes a suggestion of an active suspension system controller using fuzzy-skyhook control theory, which offers new opportunities for the improvement of vehicle ride performance. The ride comfort of the active suspension system has been evaluated using a 7 degree of freedom full vehicle mathematical model. The simulation results are presented in the time and frequency domain, also in terms of RMS values, and it’s shown that the proposed active suspension system with fuzzy-skyhook control improved the vehicle ride quality in terms of body acceleration, suspension working space and dynamic tyre load in comparison with the passive and skyhook suspension systems.

  14. Design of Immune-Algorithm-Based Adaptive Fuzzy Controllers for Active Suspension Systems

    Directory of Open Access Journals (Sweden)

    Ming-Yuan Shieh

    2014-04-01

    Full Text Available The aim of this paper is to integrate the artificial immune systems and adaptive fuzzy control for the automobile suspension system, which is regarded as a multiobjective optimization problem. Moreover, the fuzzy control rules and membership controls are then introduced for identification and memorization. It leads fast convergence in the search process. Afterwards, by using the diversity of the antibody group, trapping into local optimum can be avoided, and the system possesses a global search capacity and a faster local search for finding a global optimal solution. Experimental results show that the artificial immune system with the recognition and memory functions allows the system to rapidly converge and search for the global optimal approximate solutions.

  15. A magnetic suspension system for measuring liquid density

    Directory of Open Access Journals (Sweden)

    Luz María Centeno González

    2013-01-01

    Full Text Available Density is a derived quantity of mass and length; it is defined as mass per volume unit and its SI unit is kg/m3. National metrology institutes have been designing and building their own magnetic suspension systems during the last 5 decades for making fluid density measurements; this has allowed them to carry out research into liquids and gases’ physical characteristics. This paper was aimed at designing and developing a magnetic suspension system for a magnetic balance used in determining liquid density to be used in CENAM’s metrology density laboratories.

  16. Vibration Reduction System Using Magnetic Suspension Technology

    Directory of Open Access Journals (Sweden)

    Spychała Jarosław

    2015-01-01

    Full Text Available The article presents considerations concerning the construction of vibration reduction system using magnetic suspension technology. Presents the results of simulation, numerical and experimental the bearingless electric motor, for which successfully used this type of solution. Positive results of research and testing have become the basis for the development of the concept of building this type of active vibration reduction system , at the same time acting as a support for a technical object, which is a jet engine. Bearing failures are manifested by loss or distortion of their mass, which leads to a total destruction of the roller bearing, and thus reflected in the security. The article presents the concept of building active magnetic suspension to eliminate the bearing system of classical rolling bearing and replace it with magnetic bearing.

  17. Two-Dimensional Fuzzy Sliding Mode Control of a Field-Sensed Magnetic Suspension System

    Directory of Open Access Journals (Sweden)

    Jen-Hsing Li

    2014-01-01

    Full Text Available This paper presents the two-dimensional fuzzy sliding mode control of a field-sensed magnetic suspension system. The fuzzy rules include both the sliding manifold and its derivative. The fuzzy sliding mode control has advantages of the sliding mode control and the fuzzy control rules are minimized. Magnetic suspension systems are nonlinear and inherently unstable systems. The two-dimensional fuzzy sliding mode control can stabilize the nonlinear systems globally and attenuate chatter effectively. It is adequate to be applied to magnetic suspension systems. New design circuits of magnetic suspension systems are proposed in this paper. ARM Cortex-M3 microcontroller is utilized as a digital controller. The implemented driver, sensor, and control circuits are simpler, more inexpensive, and effective. This apparatus is satisfactory for engineering education. In the hands-on experiments, the proposed control scheme markedly improves performances of the field-sensed magnetic suspension system.

  18. Active and semi-active control of suspension systems for commercial vehicles based on preview

    NARCIS (Netherlands)

    Kok, J.J.; van Heck, J.G.A.M.; Muijderman, J.H.E.A.; Veldpaus, F.E.

    1997-01-01

    The performance of a vehicle axle/wheel suspension system is primarily determined by the comfort of the occupants, the required working space, the handling properties and, for commercial vehicles in particular, the dynamic tire forces and the load on the chassis components and on the cargo. General

  19. Progress of magnetic-suspension systems and magnetic bearings in the USSR

    International Nuclear Information System (INIS)

    Kuzin, A.V.

    1992-01-01

    This paper traces the development and progress of magnetic suspension systems and magnetic bearings in the USSR. The paper describes magnetic bearings for turbomachines, magnetic suspension systems for vibration isolation, some special measuring devices, wind tunnels, and other applications. The design, principles of operation, and dynamic characteristics of the system are presented

  20. A new pneumatic suspension system with independent stiffness and ride height tuning capabilities

    Science.gov (United States)

    Yin, Zhihong; Khajepour, Amir; Cao, Dongpu; Ebrahimi, Babak; Guo, Konghui

    2012-12-01

    This paper introduces a new pneumatic spring for vehicle suspension systems, allowing independent tuning of stiffness and ride height according to different vehicle operating conditions and driver preferences. The proposed pneumatic spring comprises a double-acting pneumatic cylinder, two accumulators and a tuning subsystem. This paper presents a detailed description of the pneumatic spring and its working principle. The mathematical model is established based on principles of thermo and fluid dynamics. An experimental setup has been designed and fabricated for testing and evaluating the proposed pneumatic spring. The analytical and experimental results confirm the capability of the new pneumatic spring system for independent tuning of stiffness and ride height. The mathematical model is verified and the capabilities of the pneumatic spring are further proved. It is concluded that this new pneumatic spring provides a more flexible suspension design alternative for meeting various conflicting suspension requirements for ride comfort and performance.

  1. Design and development of a MLS based compact active suspension system, featuring air spring and energy harvesting capabilities

    DEFF Research Database (Denmark)

    Berg, Nick Ilsø; Holm, Rasmus Koldborg; Rasmussen, Peter Omand

    2016-01-01

    This paper describes the design and development of an novel Magnetic Lead Screw based active suspension system for passenger vehicles, using a new MLS topology. The design is based on performance specifications found from ISO road profiles, with a maximum harvested energy approach. By integrating...... the PMSM motor with the MLS, it possible to construct a very compact design with an integrated air spring. The prototype is build and frictional losses and efficiency for the MLS damper unit are measured. Additional the stall force and stall torque are measured for the build prototype to validate...

  2. Development of a non-piston MR suspension rod for variable mass systems

    Science.gov (United States)

    Deng, Huaxia; Han, Guanghui; Zhang, Jin; Wang, Mingxian; Ma, Mengchao; Zhong, Xiang; Yu, Liandong

    2018-06-01

    The semi-active suspension systems for variable mass systems require long work stroke and variable damping, while the currently piston structure limits the work stroke for the magnetorheological (MR) dampers. The main work of this paper is to design a semi-active non-piston MR (NPMR) suspension rod for the reduction of the vibration of an automatic impeller washing machine, which is a typical variable mass system. The designed suspension rod locates in the suspension system that links the internal tub to the washing machine cabinet. The NPMR suspension rod includes a MR part and a air part. The MR part can provide low initial damping force and the unlimited work stroke compared with the piston MR damper. The hysteretic response tests and vibration performance evaluation with different loadings are conducted to verify the dynamic performance for the designed rod. The measured damping force of the MR part varies from 5 to 20 N. Studies of dehydration mode experiments of the washing machine indicate that its vibration acceleration with the NPMR suspension rods can reduce to half of the original passive ones in certain conditions.

  3. State observer-based sliding mode control for semi-active hydro-pneumatic suspension

    Science.gov (United States)

    Ren, Hongbin; Chen, Sizhong; Zhao, Yuzhuang; Liu, Gang; Yang, Lin

    2016-02-01

    This paper proposes an improved virtual reference model for semi-active suspension to coordinate the vehicle ride comfort and handling stability. The reference model combines the virtues of sky-hook with ground-hook control logic, and the hybrid coefficient is tuned according to the longitudinal and lateral acceleration so as to improve the vehicle stability especially in high-speed condition. Suspension state observer based on unscented Kalman filter is designed. A sliding mode controller (SMC) is developed to track the states of the reference model. The stability of the SMC strategy is proven by means of Lyapunov function taking into account the nonlinear damper characteristics and sprung mass variation of the vehicle. Finally, the performance of the controller is demonstrated under three typical working conditions: the random road excitation, speed bump road and sharp acceleration and braking. The simulation results indicated that, compared with the traditional passive suspension, the proposed control algorithm can offer a better coordination between vehicle ride comfort and handling stability. This approach provides a viable alternative to costlier active suspension control systems for commercial vehicles.

  4. Active Control of Suspension Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    In this paper some recent research on active control of very long suspension bridges, is presented. The presentation is based on research work at Aalborg University, Denmark. The active control system is based on movable flaps attached to the bridge girder. Wind load on bridges with or without...... flaps attached to the girder is briefly presented. A simple active control system is discussed. Results from wind tunnel experiments with a bridge section show that flaps can be used effectively to control bridge girder vibrations. Flutter conditions for suspension bridges with and without flaps...

  5. Muscle Activation during Push-Ups with Different Suspension Training Systems.

    Science.gov (United States)

    Calatayud, Joaquin; Borreani, Sebastien; Colado, Juan C; Martín, Fernando F; Rogers, Michael E; Behm, David G; Andersen, Lars L

    2014-09-01

    The purpose of this study was to analyze upper extremity and core muscle activation when performing push-ups with different suspension devices. Young fit male university students (n = 29) performed 3 push-ups each with 4 different suspension systems. Push-up speed was controlled using a metronome and testing order was randomized. Average amplitude of the electromyographic root mean square of Triceps Brachii, Upper Trapezius, Anterior Deltoid, Clavicular Pectoralis, Rectus Abdominis, Rectus Femoris, and Lumbar Erector Spinae was recorded. Electromyographic signals were normalized to the maximum voluntary isometric contraction (MVIC). Electromyographic data were analyzed with repeated-measures analysis of variance with a Bonferroni post hoc. Based upon global arithmetic mean of all muscles analyzed, the suspended push-up with a pulley system provided the greatest activity (37.76% of MVIC; p push-up with a pulley system also provided the greatest triceps brachii, upper trapezius, rectus femoris and erector lumbar spinae muscle activation. In contrast, more stable conditions seem more appropriate for pectoralis major and anterior deltoid muscles. Independent of the type of design, all suspension systems were especially effective training tools for reaching high levels of rectus abdominis activation. Key PointsCompared with standard push-ups on the floor, suspended push-ups increase core muscle activation.A one-anchor system with a pulley is the best option to increase TRICEP, TRAPS, LUMB and FEM muscle activity.More stable conditions such as the standard push-up or a parallel band system provide greater increases in DELT and PEC muscle activation.A suspended push-up is an effective method to achieve high muscle activity levels in the ABS.

  6. Magnetic suspension of a rotating system. Application to inertial flywheels

    International Nuclear Information System (INIS)

    Lemarquand, Guy

    1984-01-01

    The various possible magnetic suspension configurations compatible with rotating mechanical systems are defined from studies of the characteristics of different types of magnetic bearings. The results obtained are used in the design and realization of a magnetic suspension for an inertial flywheel. (author) [fr

  7. Magnetic suspension motorized spindle-cutting system dynamics analysis and vibration control review

    Directory of Open Access Journals (Sweden)

    Xiaoli QIAO

    2016-10-01

    Full Text Available The performance of high-speed spindle directly determines the development of high-end machine tools. The cutting system's dynamic characteristics and vibration control effect are inseparable with the performance of the spindle,which influence each other, synergistic effect together the cutting efficiency, the surface quality of the workpiece and tool life in machining process. So, the review status on magnetic suspension motorized spindle, magnetic suspension bearing-flexible rotor system dynamics modeling theory and status of active control technology of flexible magnetic suspension motorized spindle rotor vibration are studied, and the problems which present in the magnetic suspension flexible motorized spindle rotor systems are refined, and the development trend of magnetic levitation motorized spindle and the application prospect is forecasted.

  8. Design and analysis of the SSC [Superconducting Super Collider] dipole magnet suspension system

    International Nuclear Information System (INIS)

    Nicol, T.H.; Niemann, R.C.; Gonczy, J.D.

    1989-03-01

    The design of the suspension system for Superconducting Super Collider (SSC) dipole magnets has been driven by rigorous thermal and structural requirements. The current system, designed to meet those requirements, represents a significant departure from previous superconducting magnet suspension system designs. This paper will present a summary of the design and analysis of the vertical and lateral suspension as well as the axial anchor system employed in SSC dipole magnets. 5 refs., 9 figs., 4 tabs

  9. Suspension for the low frequency facility

    CERN Document Server

    Cella, G; Di Virgilio, A; Gaddi, A; Viceré, A

    2000-01-01

    We introduce the working principles of the VIRGO Low Frequency Facility (LFF), whose main aim is the measurement of the thermal noise in the VIRGO suspension system. We evaluate the displacement thermal noise of a mirror, which is an intermediate element of a double pendulum suspension system. This double pendulum will be suspended to the last stage of a VIRGO Super-Attenuator (SA), the prototype VIRGO suspension system being tested at the Pisa section of INFN. In the proposed configuration, we evaluate the spectrum of the thermal noise for different choices of the parameters: based on this study, we comment on the future directions to be undertaken in the LFF experiment.

  10. Optical demodulation system for digitally encoded suspension array in fluoroimmunoassay

    Science.gov (United States)

    He, Qinghua; Li, Dongmei; He, Yonghong; Guan, Tian; Zhang, Yilong; Shen, Zhiyuan; Chen, Xuejing; Liu, Siyu; Lu, Bangrong; Ji, Yanhong

    2017-09-01

    A laser-induced breakdown spectroscopy and fluorescence spectroscopy-coupled optical system is reported to demodulate digitally encoded suspension array in fluoroimmunoassay. It takes advantage of the plasma emissions of assembled elemental materials to digitally decode the suspension array, providing a more stable and accurate recognition to target biomolecules. By separating the decoding procedure of suspension array and adsorption quantity calculation of biomolecules into two independent channels, the cross talk between decoding and label signals in traditional methods had been successfully avoided, which promoted the accuracy of both processes and realized more sensitive quantitative detection of target biomolecules. We carried a multiplexed detection of several types of anti-IgG to verify the quantitative analysis performance of the system. A limit of detection of 1.48×10-10 M was achieved, demonstrating the detection sensitivity of the optical demodulation system.

  11. Adaptive Neural-Sliding Mode Control of Active Suspension System for Camera Stabilization

    Directory of Open Access Journals (Sweden)

    Feng Zhao

    2015-01-01

    Full Text Available The camera always suffers from image instability on the moving vehicle due to the unintentional vibrations caused by road roughness. This paper presents a novel adaptive neural network based on sliding mode control strategy to stabilize the image captured area of the camera. The purpose is to suppress vertical displacement of sprung mass with the application of active suspension system. Since the active suspension system has nonlinear and time varying characteristics, adaptive neural network (ANN is proposed to make the controller robustness against systematic uncertainties, which release the model-based requirement of the sliding model control, and the weighting matrix is adjusted online according to Lyapunov function. The control system consists of two loops. The outer loop is a position controller designed with sliding mode strategy, while the PID controller in the inner loop is to track the desired force. The closed loop stability and asymptotic convergence performance can be guaranteed on the basis of the Lyapunov stability theory. Finally, the simulation results show that the employed controller effectively suppresses the vibration of the camera and enhances the stabilization of the entire camera, where different excitations are considered to validate the system performance.

  12. Stabilization of Electromagnetic Suspension System Behavior by Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Abbas Najar Khoda Bakhsh

    2012-07-01

    Full Text Available Electromagnetic suspension system with a nonlinear and unstable behavior, is used in maglev trains. In this paper a linear mathematical model of system is achieved and the state feedback method is used to improve the system stability. The control coefficients are tuned by two different methods, Riccati and a new method based on Genetic algorithm. In this new proposed method, we use Genetic algorithm to achieve the optimum values of control coefficients. The results of the system simulation by Matlab indicate the effectiveness of new proposed system. When a new reference of air gap is needed or a new external force is added, the proposed system could omit the vibration and shake of the train coupe and so, passengers feel more comfortable.

  13. DC electrostatic gyro suspension system for the Gravity Probe B experiment

    Science.gov (United States)

    Wu, Chang-Huei

    1994-12-01

    The Gravity Probe B experiment is a satellite-based experiment primarily designed to test two aspects of Einstein's General Theory of Relativity by observing the spin axis drift of near-perfect gyroscopes in a 650-km circular polar orbit. The goal of this experiment is to measure the drift angles to an accuracy of 0.3 milli-arcsec after one year in orbit. As a result, electrostatically suspended free-spinning gyroscopes operating at a very low temperature became the final choice for their ultra-low Newtonian torque-induced drift rate. The Conventional AC current-driven suspension system faces two fundamental difficulties for ground gyro testing. Field emission causes rotor charging and arcing with an imperfect electrode or rotor surfaces because the electric field intensity needed to support a solid rotor in the 1-g field is more than 107 V/m. The system not only becomes unstable at a high rotor charge, which can be more than 500 volts, but may also lose control in case of arcing. Both the high voltage AC suspension signal and the high frequency (1 MHz) signal for rotor position sensing interfere with the superconducting SQUID magnetometer for spin axis readout through inductive coupling. These problems were resolved by using DC voltage to generate a suspension force and a low frequency position sensor. In addition to the Input/Output linearization algorithm developed to remove the system nonlinearity for global stability and dynamic performance, we also minimized the electric field intensity to reduce rotor charging. Experimental results verified the desired global stability and satisfactory dynamic performance. The problem of rotor charging is virtually eliminated. More importantly, the DC system is compatible with the SQUID readout system in the Science Mission configuration. Consequently, experiments in low magnetic field at a sub-micro-gauss level for SQUID design verification and trapped flux distribution study were finally realizable in ground environment

  14. Load-cell based characterization system for a "Violin-Mode" shadow-sensor in advanced LIGO suspensions

    Science.gov (United States)

    Lockerbie, N. A.; Tokmakov, K. V.

    2016-07-01

    The background to this work was a prototype shadow sensor, which was designed for retro-fitting to an advanced LIGO (Laser Interferometer Gravitational wave Observatory) test-mass/mirror suspension, in which 40 kg test-mass/mirrors are each suspended by four approximately 600 mm long by 0.4 mm diameter fused-silica suspension fibres. The shadow sensor comprised a LED source of Near InfraRed (NIR) radiation and a rectangular silicon photodiode detector, which, together, were to bracket the fibre under test. The aim was to detect transverse Violin-Mode resonances in the suspension fibres. Part of the testing procedure involved tensioning a silica fibre sample and translating it transversely through the illuminating NIR beam, so as to measure the DC responsivity of the detection system to fibre displacement. However, an equally important part of the procedure, reported here, was to keep the fibre under test stationary within the beam, whilst trying to detect low-level AC Violin-Mode resonances excited on the fibre, in order to confirm the primary function of the sensor. Therefore, a tensioning system, incorporating a load-cell readout, was built into the test fibre's holder. The fibre then was excited by a signal generator, audio power amplifier, and distant loudspeaker, and clear resonances were detected. A theory for the expected fundamental resonant frequency as a function of fibre tension was developed and is reported here, and this theory was found to match closely with the detected resonant frequencies as they varied with tension. Consequently, the resonances seen were identified as being proper Violin-Mode fundamental resonances of the fibre, and the operation of the Violin-Mode detection system was validated.

  15. Fatigue Life Prediction of Package of Suspension Automotive Under Random Vibration Based on Road Roughness

    Directory of Open Access Journals (Sweden)

    Kazem Reza Kashyzadeh

    2015-09-01

    Full Text Available The impact of a suitable suspension system for passenger comfort and vehicle steering is an obvious order and direct impact on the safety of passengers must be considered, to do so different kinds of tests must be exerted, one of these is fatigue testing which is one of the most significant ones. Another issue is the high cost in practical ways, and to cope with this issue various ways must be assessed and analyzed, one of the best and the most efficient ways is modelling and testing in virtual software environments. In the present paper, predict fatigue life of suspension component and package of automotive suspension are the main purposes. First, using MATLAB software, road roughness according to the intercity roads for constant vehicle velocity (100 Km/h has been studied. After that frequency response of components has been analysed, its critical points determined to calculate the fatigue life of the part, and the amount of critical stress obtained based on Von Misses, Tresca and Max Principle criterion for a quarter car model (passive suspension System in 206 Peugeot. Fatigue life of the vehicle components are calculated in terms of kilo-Meters in specialized fatigue software such as 116944, 92638.9, 46388.9 and 191388.9 Km respectively wheel hub, pitman arm, suspension arm and package of suspension. Finally, to prove the given results of the finite element method compared with reported results by other researchers and the results match very well with those.

  16. Adaptive suspension strategy for a double wishbone suspension through camber and toe optimization

    Directory of Open Access Journals (Sweden)

    C. Kavitha

    2018-02-01

    Full Text Available A suspension system is responsible for the safety of vehicle during its manoeuvre. It serves the dual purpose of providing stability to the vehicle while providing a comfortable ride quality to the occupants. Recent trends in suspension system have focused on improving comfort and handling of vehicles while keeping the cost, space and feasibility of manufacturing in the constraint. This paper proposes a method for improving handling characteristics of a vehicle by controlling camber and toe angle using variable length arms in an adaptive manner. In order to study the effect of dynamic characteristics of the suspension system, a simulation study has been done in this work. A quarter car physical model with double wishbone suspension geometry is modelled in SolidWorks. It is then imported and simulated using SimMechanics platform in MATLAB. The output characteristics of the passive system (without variable length arms were validated on MSC ADAMS software. The adaptive system intends to improve vehicle handling characteristics by controlling the camber and toe angles. This is accomplished by two telescopic arms with an actuator which changes the camber and toe angle of the wheel dynamically to deliver best possible traction and manoeuvrability. Two PID controllers are employed to trigger the actuators based on the camber and toe angle from the sensors for reducing the error existing between the actual and desired value. The arms are driven by actuators in a closed loop feedback manner with help of a separate control system. Comparison between active and passive systems is carried out by analysing graphs of various parameters obtained from MATLAB simulation. From the results, it is observed that there is a reduction of 58% in the camber and 96% in toe gain. Hence, the system provides the scope of considerable adaptive strategy in controlling dynamic characteristics of the suspension system.

  17. A comparison of optimal semi-active suspension systems regarding vehicle ride comfort

    Science.gov (United States)

    Koulocheris, Dimitrios; Papaioannou, Georgios; Chrysos, Emmanouil

    2017-10-01

    The aim of this work is to present a comparison of the main semi active suspension systems used in a passenger car, after having optimized the suspension systems of the vehicle model in respect with ride comfort and road holding. Thus, a half car model, equipped with controllable dampers, along with a seat and a driver was implemented. Semi-active suspensions have received a lot of attention since they seem to provide the best compromise between cost (energy consumption, actuators/sensors hardware) and performance in comparison with active and passive suspensions. In this work, the semi active suspension systems studied are comfort oriented and consist of (a) the two version of Skyhook control (two states skyhook and skyhook linear approximation damper), (b) the acceleration driven damper (ADD), (c) the power driven damper (PDD), (d) the combination of Skyhook and ADD (Mixed Skyhook-ADD) and (e) the combination of the two with the use of a sensor. The half car model equipped with the above suspension systems was excited by a road bump, and was optimized using genetic algorithms (GA) in respect with ride comfort and road holding. This study aims to highlight how the optimization of the vehicle model could lead to the best compromise between ride comfort and road holding, overcoming their well-known trade-off. The optimum results were compared with important performance metrics regarding the vehicle’s dynamic behaviour in general.

  18. Use of MBS (ADAMS / CAR software in simulations of vehicle suspension systems

    Directory of Open Access Journals (Sweden)

    Łukasz KONIECZNY

    2014-03-01

    Full Text Available The results of the examination of a vehicle suspension system in the plate position are presented in the paper. The model vehicle is a Fiat Seicento with front independent suspension, McPherson type, with the steering system and with the semi-trailing arm in the rear suspension. Identification of the model was made by comparing the simulation results with the results from the test stand. A multibody model of the vehicle will be used in studies of the impact of shock absorber technical conditions on the dynamics of automotive vehicles.

  19. Design analysis of formula student race car suspension system

    Science.gov (United States)

    Wirawan, Julian Wisnu; Ubaidillah, Aditra, Rama; Alnursyah, Rafli; Rahman, Rizki Abdul; Cahyono, Sukmaji Indro

    2018-02-01

    Design analysis of suspension especially for racecar suspension is very crucial to achieve maximum performance and handling. Suspension design may vary depending on the road terrain and the vehicle purpose itself, such as high speed or off-road vehicle. This paper focused on the suspension which used for racecar vehicle. The suspension type used was unequal double wishbone. This model is used because of its stability for high-speed usage compared to another kind of suspension. The suspension parameter was calculated to achieve desired performance. The result is the motion ratio of the designed suspension geometry. The obtained value of motion ratio was 1:2 for front suspension and 1:1 for the rear suspension. These calculation result the front suspension is still too soft, which the optimal motion ratio should be kept around 1:1 for better handling. This problem caused by the lack of space for suspension linkage.

  20. Macrostructure of smectite-water systems. Influence of anionic poly-electrolytes on the organisation of montmorillonite suspensions

    International Nuclear Information System (INIS)

    Morvan, Mikel

    1993-01-01

    In its first part, this research thesis reports a bibliographical study which aimed at highlighting the main aspects of smectite swelling, discusses the organisation of smectite suspension, and briefly presents the knowledge on clay-polymer mixtures. Then, the author describes the method he used to characterise clay suspensions (relaxation, MNR, osmometric techniques, small-angle X-ray diffraction), and theoretical elements required to interpret results. He addresses more particularly the organisation of smectite-water systems with either a natural smectite (montmorillonite) or a synthetic one (laponite) which have different geometries. The last part addresses the interactions between a montmorillonite suspension and sodium polyacrylates. The author, based on the use of small-angle X-ray diffraction and the measurement of the polyelectrolyte osmotic pressure, proposes a new interpretation of the action mechanism of an anionic polyelectrolyte of low molecular mass within a montmorillonite suspension

  1. Boundary Effects and Shear Thickening of Colloidal Suspensions: A study based on measurement of Suspension Microstructure

    Science.gov (United States)

    Perera, M. Tharanga D.

    Microstructure is key to understanding rheological behaviors of flowing particulate suspensions. During the past decade, Stokesian Dynamics simulations have been the dominant method of determining suspension microstructure. Structure results obtained numerically reveal that an anisotropic structure is formed under high Peclet (Pe) number conditions. Researchers have used various experimental techniques such as small angle neutron scattering (SANS) and light scattering methods to validate microstructure. This work outlines an experimental technique based on confocal microscopy to study microstructure of a colloidal suspension in an index-matched fluid flowing in a microchannel. High resolution scans determining individual particle locations in suspensions 30-50 vol % yield quantitative results of the local microstructure in the form of the pair distribution function, g(r). From these experimentally determined g(r), the effect of shear rate, quantified by the Peclet number as a ratio of shear and Brownian stress, on the suspension viscosity and normal stress follow that seen in macroscopic rheological measurements and simulations. It is generally believed that shear thickening behavior of colloidal suspensions is driven by the formation of hydroclusters. From measurements of particle locations, hydroclusters are identified. The number of hydroclusters grows exponentially with increasing Pe, and the onset of shear thickening is driven by the increase in formation of clusters having 5-8 particles. At higher Pe, we notice the emergence of 12 or more particle clusters. The internal structure of these hydroclusters has been investigated, and there is some evidence that particles internal to hydroclusters preferentially align along the 45° and 135° axis. Beyond observations of bulk suspension behavior, the influence of boundaries on suspension microstructure is also investigated. Experiments were performed for suspensions flowing over smooth walls, made of glass

  2. The modecleaner system and suspension aspects of GEO 600

    CERN Document Server

    Gossler, S; Freise, A; Grote, H; Lück, H B; McNamara, P; Plissi, M V; Robertson, D I; Robertson, N A; Skeldon, K D; Strain, K A; Torrie, C I; Ward, H; Willke, B; Hough, J; Danzmann, K

    2002-01-01

    GEO 600 uses two 8 m triangular ring cavities as a modecleaner system for the stabilization of the laser. To isolate the cavities with respect to the seismic noise the optical components are suspended as double pendulums. The resonances of these pendulums are damped by a local-control loop via magnet-coil actuators acting on the intermediate masses. The suspension scheme and the measured key data (i.e. finesse, linewidth, visibility, throughput and in-lock durations of the cavities, as well as the isolation performance and the resulting frequency stability) of the modecleaner system will be given in this paper. Furthermore an overview of the GEO 600 interferometer suspension will be given.

  3. Optimization of damping in the passive automotive suspension system with using two quarter-car models

    Science.gov (United States)

    Lozia, Z.; Zdanowicz, P.

    2016-09-01

    The paper presents the optimization of damping in the passive suspension system of a motor vehicle moving rectilinearly with a constant speed on a road with rough surface of random irregularities, described according to the ISO classification. Two quarter-car 2DoF models, linear and non-linear, were used; in the latter, nonlinearities of spring characteristics of the suspension system and pneumatic tyres, sliding friction in the suspension system, and wheel lift-off were taken into account. The smoothing properties of vehicle tyres were represented in both models. The calculations were carried out for three roads of different quality, with simulating four vehicle speeds. Statistical measures of vertical vehicle body vibrations and of changes in the vertical tyre/road contact force were used as the criteria of system optimization and model comparison. The design suspension displacement limit was also taken into account. The optimum suspension damping coefficient was determined and the impact of undesirable sliding friction in the suspension system on the calculation results was estimated. The results obtained make it possible to evaluate the impact of the structure and complexity of the model used on the results of the optimization.

  4. Load-cell based characterization system for a “Violin-Mode” shadow-sensor in advanced LIGO suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Lockerbie, N. A.; Tokmakov, K. V. [SUPA (Scottish Universities Physics Alliance) Department of Physics, University of Strathclyde, 107 Rottenrow, Glasgow G4 0NG (United Kingdom)

    2016-07-15

    The background to this work was a prototype shadow sensor, which was designed for retro-fitting to an advanced LIGO (Laser Interferometer Gravitational wave Observatory) test-mass/mirror suspension, in which 40 kg test-mass/mirrors are each suspended by four approximately 600 mm long by 0.4 mm diameter fused-silica suspension fibres. The shadow sensor comprised a LED source of Near InfraRed (NIR) radiation and a rectangular silicon photodiode detector, which, together, were to bracket the fibre under test. The aim was to detect transverse Violin-Mode resonances in the suspension fibres. Part of the testing procedure involved tensioning a silica fibre sample and translating it transversely through the illuminating NIR beam, so as to measure the DC responsivity of the detection system to fibre displacement. However, an equally important part of the procedure, reported here, was to keep the fibre under test stationary within the beam, whilst trying to detect low-level AC Violin-Mode resonances excited on the fibre, in order to confirm the primary function of the sensor. Therefore, a tensioning system, incorporating a load-cell readout, was built into the test fibre’s holder. The fibre then was excited by a signal generator, audio power amplifier, and distant loudspeaker, and clear resonances were detected. A theory for the expected fundamental resonant frequency as a function of fibre tension was developed and is reported here, and this theory was found to match closely with the detected resonant frequencies as they varied with tension. Consequently, the resonances seen were identified as being proper Violin-Mode fundamental resonances of the fibre, and the operation of the Violin-Mode detection system was validated.

  5. Load-cell based characterization system for a “Violin-Mode” shadow-sensor in advanced LIGO suspensions

    International Nuclear Information System (INIS)

    Lockerbie, N. A.; Tokmakov, K. V.

    2016-01-01

    The background to this work was a prototype shadow sensor, which was designed for retro-fitting to an advanced LIGO (Laser Interferometer Gravitational wave Observatory) test-mass/mirror suspension, in which 40 kg test-mass/mirrors are each suspended by four approximately 600 mm long by 0.4 mm diameter fused-silica suspension fibres. The shadow sensor comprised a LED source of Near InfraRed (NIR) radiation and a rectangular silicon photodiode detector, which, together, were to bracket the fibre under test. The aim was to detect transverse Violin-Mode resonances in the suspension fibres. Part of the testing procedure involved tensioning a silica fibre sample and translating it transversely through the illuminating NIR beam, so as to measure the DC responsivity of the detection system to fibre displacement. However, an equally important part of the procedure, reported here, was to keep the fibre under test stationary within the beam, whilst trying to detect low-level AC Violin-Mode resonances excited on the fibre, in order to confirm the primary function of the sensor. Therefore, a tensioning system, incorporating a load-cell readout, was built into the test fibre’s holder. The fibre then was excited by a signal generator, audio power amplifier, and distant loudspeaker, and clear resonances were detected. A theory for the expected fundamental resonant frequency as a function of fibre tension was developed and is reported here, and this theory was found to match closely with the detected resonant frequencies as they varied with tension. Consequently, the resonances seen were identified as being proper Violin-Mode fundamental resonances of the fibre, and the operation of the Violin-Mode detection system was validated.

  6. A study of the free vibration of suspension rod based on four-stage arm mechanism by using computer simulation

    Directory of Open Access Journals (Sweden)

    Melnychuk S.V.

    2016-08-01

    Full Text Available We analyze the current state of the prospects and problems of using computer technology to determine the operating parameters of movement of the vehicle. Scientific works related to the study of the properties of the vehicle smooth ride are studied. The following example shows that the modern researches of smooth ride do not pay enough attention to issues associated with the processes that occur in the suspension rod of a vehicle. Scientific works related to the choice of the optimal and simple CAD system for conducting computer simulation tests are overviewed. We developed an animating model of experimental car in SOLIDWORKS environment with the staff suspension rod and the suspension rod based on four-stage arm mechanism, which allows a wide range of tests of components of the vehicle. Methodology and hardware-software complex for testing a car are developed. A test of a vehicle of category N1 is conducted. A computer simulation of the motion of the smooth ride of the car with suspension rod based on four-stage arm mechanism is conducted. The comparative analysis of suspension rod performance based on four-stage arm mechanism is conducted.

  7. Kineto-dynamic design optimisation for vehicle-specific seat-suspension systems

    Science.gov (United States)

    Shangguan, Wen-Bin; Shui, Yijie; Rakheja, Subhash

    2017-11-01

    Designs and analyses of seat-suspension systems are invariably performed considering effective vertical spring rate and damping properties, while neglecting important contributions due to kinematics of the widely used cross-linkage mechanism. In this study, a kineto-dynamic model of a seat-suspension is formulated to obtain relations for effective vertical suspension stiffness and damping characteristics as functions of those of the air spring and the hydraulic damper, respectively. The proposed relations are verified through simulations of the multi-body dynamic model of the cross-linkage seat-suspension in the ADAMS platform. The validity of the kineto-dynamic model is also demonstrated through comparisons of its vibration transmission response with the experimental data. The model is used to identify optimal air spring coordinates to attain nearly constant natural frequency of the suspension, irrespective of the seated body mass and seated height. A methodology is further proposed to identify optimal damping requirements for vehicle-specific suspension designs to achieve minimal seat effective amplitude transmissibility (SEAT) and vibration dose value (VDV) considering vibration spectra of different classes of earthmoving vehicles. The shock and vibration isolation performance potentials of the optimal designs are evaluated under selected vehicle vibration superimposed with shock motions. Results show that the vehicle-specific optimal designs could provide substantial reductions in the SEAT and VDV values for the vehicle classes considered.

  8. Evaluating damping elements for two-stage suspension vehicles

    Directory of Open Access Journals (Sweden)

    Ronald M. Martinod R.

    2012-01-01

    Full Text Available The technical state of the damping elements for a vehicle having two-stage suspension was evaluated by using numerical models based on the multi-body system theory; a set of virtual tests used the eigenproblem mathematical method. A test was developed based on experimental modal analysis (EMA applied to a physical system as the basis for validating the numerical models. The study focused on evaluating vehicle dynamics to determine the influence of the dampers’ technical state in each suspension state.

  9. Modal and Dynamic Analysis of a Vehicle with Kinetic Dynamic Suspension System

    Directory of Open Access Journals (Sweden)

    Bangji Zhang

    2016-01-01

    Full Text Available A novel kinetic dynamic suspension (KDS system is presented for the cooperative control of the roll and warp motion modes of off-road vehicles. The proposed KDS system consists of two hydraulic cylinders acting on the antiroll bars. Hence, the antiroll bars are not completely replaced by the hydraulic system, but both systems are installed. In this paper, the vibration analysis in terms of natural frequencies of different motion modes in frequency domain for an off-road vehicle equipped with different configurable suspension systems is studied by using the modal analysis method. The dynamic responses of the vehicle with different configurable suspension systems are investigated under different road excitations and maneuvers. The results of the modal and dynamic analysis prove that the KDS system can reduce the roll and articulation motions of the off-road vehicle without adding extra bounce stiffness and deteriorating the ride comfort. Furthermore, the roll stiffness is increased and the warp stiffness is decreased by the KDS system, which could significantly enhance handing performance and off-road capability.

  10. Multivectored Superficial Muscular Aponeurotic System Suspension for Facial Paralysis.

    Science.gov (United States)

    Leach, Garrison; Kurnik, Nicole; Joganic, Jessica; Joganic, Edward

    2017-06-01

    Facial paralysis is a devastating condition that may cause severe cosmetic and functional deformities. In this study we describe our technique for superficial muscular aponeurotic system (SMAS) suspension using barbed suture and compare the vectors of suspension in relation to the underlying musculature. This study also quantifies the improvements in postoperative symmetry using traditional anthropologic landmarks. The efficacy of this procedure for improving facial paralysis was determined by comparing anthropometric indices and using Procrustes distance between 4 groupings of homologous landmarks plotted on each patient's preoperative and postoperative photos. Geometric morphometrics was used to evaluate change in facial shape and improvement in symmetry postoperatively.To analyze the vector of suspension in relation to the underlying musculature, specific anthropologic landmarks were used to calculate the vector of the musculature in 3 facial hemispheres from cadaveric controls against the vector of repair in our patients. Ten patients were included in our study. Subjectively, great improvement in functional status was achieved. Geometric morphometric analysis demonstrated a statistically significant improvement in facial symmetry. Cadaveric dissection demonstrated that the suture should be placed in the SMAS in vectors parallel to the underlying musculature to achieve these results. There were no complications in our study to date. In conclusion, multivectored SMAS suture suspension is an effective method for restoring static suspension of the face after facial paralysis. This method has the benefit of producing quick, reliable results with improved function, low cost, and low morbidity.

  11. A semi-active control suspension system for railway vehicles with magnetorheological fluid dampers

    Science.gov (United States)

    Wei, Xiukun; Zhu, Ming; Jia, Limin

    2016-07-01

    The high-speed train has achieved great progress in the last decades. It is one of the most important modes of transportation between cities. With the rapid development of the high-speed train, its safety issue is paid much more attention than ever before. To improve the stability of the vehicle with high speed, extra dampers (i.e. anti-hunting damper) are used in the traditional bogies with passive suspension system. However, the curving performance of the vehicle is undermined due to the extra lateral force generated by the dampers. The active suspension systems proposed in the last decades attempt to solve the vehicle steering issue. However, the active suspension systems need extra actuators driven by electrical power or hydraulic power. There are some implementation and even safety issues which are not easy to be overcome. In this paper, an innovative semi-active controlled lateral suspension system for railway vehicles is proposed. Four magnetorheological fluid dampers are fixed to the primary suspension system of each bogie. They are controlled by online controllers for enhancing the running stability on the straight track line on the one hand and further improving the curving performance by controlling the damper force on the other hand. Two control strategies are proposed in the light of the pure rolling concept. The effectiveness of the proposed strategies is demonstrated by SIMPACK and Matlab co-simulation for a full railway vehicle with two conventional bogies.

  12. Lateral Vibration Attenuation by the Dynamic Adjustment of Bias Currents in Magnetic Suspension System

    International Nuclear Information System (INIS)

    Mizuno, Takeshi; Takasaki, Masaya; Ishino, Yuji

    2016-01-01

    Switching stiffness control is applied to attenuate vibration in the lateral directions in an active magnetic suspension system with electromagnets operated in differential mode. The magnetic suspension system using the attractive force between magnetized bodies is inherently unstable in the normal direction so that feedback control is necessary to achieve stable suspension. In contrast, it can be stable in the lateral directions due to the edge effects in the magnetic circuits. In several applications, such passive suspension is used in combination with the active one to reduce cost and space. However, damping in the lateral directions is generally small. As a result, induced vibrations in these directions are hardly attenuated. To suppress such vibration without any additional actuator (electromagnet), switching stiffness control is applied to an magnetic suspension system operated in the differential mode. The stiffness in the lateral direction is adjusted by varying the bias currents of an opposed pair of electromagnets located in the normal direction simultaneously according to the motion of the suspended object. When the varied bias currents are adjusted for the additive normal forces cancel each other, such control does not affect the suspension in the normal direction. The effectiveness of the proposed control methods is confirmed experimentally. (paper)

  13. Electrochemical analysis in a liposome suspension using lapachol as a hydrophobic electro active species.

    Science.gov (United States)

    Okumura, Noriko; Wakamatsu, Shiori; Uno, Bunji

    2014-01-01

    This study demonstrated that the electro-chemical analysis of hydrophobic quinones can be performed in liposome suspension systems. We prepared and analyzed liposome suspensions containing lapachol, which is a quinone-based anti-tumor activity compound. In this suspension system, a simple one redox couple of lapachol is observed. These results are quite different from those obtained in organic solvents. In addition, the pH dependence of redox behaviors of lapachol could be observed in multilamellar vesicle (MLV) suspension system. This MLV suspension system method may approximate the electrochemical behavior of hydrophobic compounds in aqueous conditions. A benefit of this liposome suspension system for electrochemical analysis is that it enables to observe water-insoluble compounds without using organic solvents.

  14. Integrated null-flux suspension and multiphase propulsion system for magnetically-levitated vehicles

    Science.gov (United States)

    Rote, D.M.; He, J.; Johnson, L.R.

    1994-01-04

    A propulsion and stabilization system are described comprising a series of coils mounted vertically on the walls of the guideway to provide suspension, lateral guidance, and propulsion of a magnetically levitated vehicle. This system further allows for altering the magnetic field effects by changing the relative position of the loops comprising the coils either longitudinally and/or vertically with resulting changes in the propulsion, the vertical stability, and the suspension. 8 figures.

  15. Integrated null-flux suspension and multiphase propulsion system for magnetically-levitated vehicles

    Science.gov (United States)

    Rote, Donald M.; He, Jianliang; Johnson, Larry R.

    1994-01-01

    A propulsion and stabilization system comprising a series of FIG. 8 coils mounted vertically on the walls of the guideway to provide suspension, lateral guidance and propulsion of a magnetically levitated vehicle. This system further allows for altering the magnetic field effects by changing the relative position of the loops comprising the FIG. 8 coils either longitudinally and/or vertically with resulting changes in the propulsion, the vertical stability, and the suspension.

  16. Vibration control of an MR vehicle suspension system considering both hysteretic behavior and parameter variation

    International Nuclear Information System (INIS)

    Choi, Seung-Bok; Seong, Min-Sang; Ha, Sung-Hoon

    2009-01-01

    This paper presents vibration control responses of a controllable magnetorheological (MR) suspension system considering the two most important characteristics of the system; the field-dependent hysteretic behavior of the MR damper and the parameter variation of the suspension. In order to achieve this goal, a cylindrical MR damper which is applicable to a middle-sized passenger car is designed and manufactured. After verifying the damping force controllability, the field-dependent hysteretic behavior of the MR damper is identified using the Preisach hysteresis model. The full-vehicle suspension model is then derived by considering vertical, pitch and roll motions. An H ∞ controller is designed by treating the sprung mass of the vehicle as a parameter variation and integrating it with the hysteretic compensator which produces additional control input. In order to demonstrate the effectiveness and robustness of the proposed control system, the hardware-in-the-loop simulation (HILS) methodology is adopted by integrating the suspension model with the proposed MR damper. Vibration control responses of the vehicle suspension system such as vertical acceleration are evaluated under both bump and random road conditions

  17. An approach for multi-objective optimization of vehicle suspension system

    Science.gov (United States)

    Koulocheris, D.; Papaioannou, G.; Christodoulou, D.

    2017-10-01

    In this paper, a half car model of with nonlinear suspension systems is selected in order to study the vertical vibrations and optimize its suspension system with respect to ride comfort and road holding. A road bump was used as road profile. At first, the optimization problem is solved with the use of Genetic Algorithms with respect to 6 optimization targets. Then the k - ɛ optimization method was implemented to locate one optimum solution. Furthermore, an alternative approach is presented in this work: the previous optimization targets are separated in main and supplementary ones, depending on their importance in the analysis. The supplementary targets are not crucial to the optimization but they could enhance the main objectives. Thus, the problem was solved again using Genetic Algorithms with respect to the 3 main targets of the optimization. Having obtained the Pareto set of solutions, the k - ɛ optimality method was implemented for the 3 main targets and the supplementary ones, evaluated by the simulation of the vehicle model. The results of both cases are presented and discussed in terms of convergence of the optimization and computational time. The optimum solutions acquired from both cases are compared based on performance metrics as well.

  18. Design and Optimization of Intelligent Service Robot Suspension System Using Dynamic Model

    International Nuclear Information System (INIS)

    Choi, Seong Hoon; Park, Tae Won; Lee, Soo Ho; Jung, Sung Pil; Jun, Kab Jin; Yoon, J. W.

    2010-01-01

    Recently, an intelligent service robot is being developed for use in guiding and providing information to visitors about the building at public institutions. The intelligent robot has a sensor at the bottom to recognize its location. Four wheels, which are arranged in the form of a lozenge, support the robot. This robot cannot be operated on uneven ground because its driving parts are attached to its main body that contains the important internal components. Continuous impact with the ground can change the precise positions of the components and weaken the connection between each structural part. In this paper, the design of the suspension system for such a robot is described. The dynamic model of the robot is created, and the driving characteristics of the robot with the designed suspension system are simulated. Additionally, the suspension system is optimized to reduce the impact for the robot components

  19. DESIGN AND APPLICATION OF MAGNETIC BEARING SUSPENSION SYSTEM IN A THREE PHASE INDUCTION MOTOR

    Directory of Open Access Journals (Sweden)

    Osman GÜRDAL

    1998-03-01

    Full Text Available The current popularity of suspension and levitation stems no doubt the possibilities in high-speed ground transportation schemes. Although these are both challenging and exciting, there is considerable scope for application of suspension techniques to achieving frictionless bearing. The requirement in this case is often for close tolerances, low power consumption, small airgaps and ingeneral, compactness. Thus, magnetic suspension using DC electromagnets schemes have received more attention than the other techniques of repulsion levitation. Proposed prototype system consists of a conventional stator and its rotor without iron core, set of electromagnets for suspension of rotor shaft and set of compensation circuits feedbacked by optical-transducers. Prototyped system is aimed as a laboratory demonstration tool so there is no challenging to exceed the speeds of 1500 rev/min that is the speed of motor with mechanical bearings. Magnetic bearing suspension system provides a high impact visual demonstration of many principles in undergraduate educational programs in electrical education, e.g., electromagnetic design, PD controlled compensation of a unstable control system and power amplifier design. The system is capable of giving a good comparison between mechanical and magnetic bearing up to speeds 350 rev/min. Power losses without load show about 15% reduction with magnetic bearing. The noise of the motor is also decreased to a low level.

  20. Pair-correlations in swimmer suspensions

    Science.gov (United States)

    Nambiar, Sankalp; Subramanian, Ganesh

    2017-11-01

    Suspensions of rear-actuated swimming microorganisms, such as E.coli, exhibit several interesting phenomena including spontaneous pattern formation above a critical concentration, novel rheological properties, shear-induced concentration banding etc. Explanations based on mean-field theory are only qualitative, since interactions between swimmers are important for typical experimental concentrations. We analytically characterize the hydrodynamic pair-interactions in a quiescent suspension of slender straight swimmers. The pair-correlation, calculated at leading order by integrating the swimmer velocity disturbances along straight trajectories, decays as 1/r2 for r >> L (L being the swimmer size). This allows us to characterize both polar and nematic correlations in an interacting swimmer suspension. In the absence of correlations, the velocity covariance asymptotes from a constant for r > L, the latter being characteristic of a suspension of non-interacting point force-dipoles. On including correlations, the slow decay of the pair-orientation correlation leads to an additional contribution to the velocity covariance that diverges logarithmically with system size.

  1. Discrete-time sliding mode control for MR vehicle suspension system

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, J W; Choi, S B [Smart Structures and Systems Laboratory, Department of Mechanical Engineering, Inha University, Incheon 402-751 (Korea, Republic of); Wereley, N M [Smart Structures Laboratory, Department of Aerospace Engineering, University of Maryland, College Park, MD 20742 (United States)], E-mail: seungbok@inha.ac.kr

    2009-02-01

    This paper presents control performance of a full-vehicle suspension system featuring magnetorheological (MR) dampers via a discrete-time sliding mode control algorithm (DSMC). A cylindrical MR damper is designed by incorporating Bingham model of the MR fluid and the field-dependent damping characteristics of the MR damper are evaluated. A full-vehicle suspension model installed with independent four MR dampers is constructed and the governing equations which include vertical, pitch and roll motion are derived. A discrete-time control model is established with considering system uncertainties and a discrete-time sliding mode controller which has inherent robustness to model uncertainty and external disturbance is formulated. Vibration control performances under bump excitation are evaluated and presented.

  2. Discrete-time sliding mode control for MR vehicle suspension system

    International Nuclear Information System (INIS)

    Sohn, J W; Choi, S B; Wereley, N M

    2009-01-01

    This paper presents control performance of a full-vehicle suspension system featuring magnetorheological (MR) dampers via a discrete-time sliding mode control algorithm (DSMC). A cylindrical MR damper is designed by incorporating Bingham model of the MR fluid and the field-dependent damping characteristics of the MR damper are evaluated. A full-vehicle suspension model installed with independent four MR dampers is constructed and the governing equations which include vertical, pitch and roll motion are derived. A discrete-time control model is established with considering system uncertainties and a discrete-time sliding mode controller which has inherent robustness to model uncertainty and external disturbance is formulated. Vibration control performances under bump excitation are evaluated and presented.

  3. Administrative license suspension: Does length of suspension matter?

    Science.gov (United States)

    Fell, James C; Scherer, Michael

    2017-08-18

    Administrative license revocation (ALR) laws, which provide that the license of a driver with a blood alcohol concentration at or over the illegal limit is subject to an immediate suspension by the state department of motor vehicles, are an example of a traffic law in which the sanction rapidly follows the offense. The power of ALR laws has been attributed to how swiftly the sanction is applied, but does the length of suspension matter? Our objectives were to (a) determine the relationship of the ALR suspension length to the prevalence of drinking drivers relative to sober drivers in fatal crashes and (b) estimate the extent to which the relationship is associated to the general deterrent effect compared to the specific deterrent effect of the law. Data comparing the impact of ALR law implementation and ALR law suspension periods were analyzed using structural equation modeling techniques on the ratio of drinking drivers to nondrinking drivers in fatal crashes from the Fatality Analysis Reporting System (FARS). States with an ALR law with a short suspension period (1-30 days) had a significantly lower drinking driver ratio than states with no ALR law. States with a suspension period of 91-180 days had significantly lower ratios than states with shorter suspension periods, while the three states with suspension lengths of 181 days or longer had significantly lower ratios than states with shorter suspension periods. The implementation of any ALR law was associated with a 13.1% decrease in the drinking/nondrinking driver fatal crash ratio but only a 1.8% decrease in the intoxicated/nonintoxicated fatal crash ratio. The ALR laws and suspension lengths had a significant general deterrent effect, but no specific deterrent effect. States might want to keep (or adopt) ALR laws for their general deterrent effects and pursue alternatives for specific deterrent effects. States with short ALR suspension periods should consider lengthening them to 91 days or longer.

  4. Demonstration of a switchable damping system to allow low-noise operation of high-Q low-mass suspension systems

    Science.gov (United States)

    Hennig, Jan-Simon; Barr, Bryan W.; Bell, Angus S.; Cunningham, William; Danilishin, Stefan L.; Dupej, Peter; Gräf, Christian; Hough, James; Huttner, Sabina H.; Jones, Russell; Leavey, Sean S.; Pascucci, Daniela; Sinclair, Martin; Sorazu, Borja; Spencer, Andrew; Steinlechner, Sebastian; Strain, Kenneth A.; Wright, Jennifer; Zhang, Teng; Hild, Stefan

    2017-12-01

    Low-mass suspension systems with high-Q pendulum stages are used to enable quantum radiation pressure noise limited experiments. Utilizing multiple pendulum stages with vertical blade springs and materials with high-quality factors provides attenuation of seismic and thermal noise; however, damping of these high-Q pendulum systems in multiple degrees of freedom is essential for practical implementation. Viscous damping such as eddy-current damping can be employed, but it introduces displacement noise from force noise due to thermal fluctuations in the damping system. In this paper we demonstrate a passive damping system with adjustable damping strength as a solution for this problem that can be used for low-mass suspension systems without adding additional displacement noise in science mode. We show a reduction of the damping factor by a factor of 8 on a test suspension and provide a general optimization for this system.

  5. Robust finite-time tracking control for nonlinear suspension systems via disturbance compensation

    Science.gov (United States)

    Pan, Huihui; Jing, Xingjian; Sun, Weichao

    2017-05-01

    This paper focuses on the finite-time tracking control with external disturbance for active suspension systems. In order to compensate unknown disturbance efficiently, a disturbance compensator with finite-time convergence property is studied. By analyzing the discontinuous phenomenon of classical disturbance compensation techniques, this study presents a simple approach to construct a continuous compensator satisfying the finite-time disturbance rejection performance. According to the finite-time separation principle, the design procedures of the nominal controller for the suspension system without disturbance and the disturbance compensator can be implemented in a completely independent manner. Therefore, the overall control law for the closed-loop system is continuous, which offers some distinct advantages over the existing discontinuous ones. From the perspective of practical implementation, the continuous controller can avoid effectively the unexpected chattering in active suspension control. Comparative experimental results are presented and discussed to illustrate the advantage and effectiveness of the proposed control strategy.

  6. Sky-Hook Control and Kalman Filtering in Nonlinear Model of Tracked Vehicle Suspension System

    Directory of Open Access Journals (Sweden)

    Jurkiewicz Andrzej

    2017-09-01

    Full Text Available The essence of the undertaken topic is application of the continuous sky-hook control strategy and the Extended Kalman Filter as the state observer in the 2S1 tracked vehicle suspension system. The half-car model of this suspension system consists of seven logarithmic spiral springs and two magnetorheological dampers which has been described by the Bingham model. The applied continuous sky-hook control strategy considers nonlinear stiffness characteristic of the logarithmic spiral springs. The control is determined on estimates generated by the Extended Kalman Filter. Improve of ride comfort is verified by comparing simulation results, under the same driving conditions, of controlled and passive vehicle suspension systems.

  7. Digital control of wind tunnel magnetic suspension and balance systems

    Science.gov (United States)

    Britcher, Colin P.; Goodyer, Michael J.; Eskins, Jonathan; Parker, David; Halford, Robert J.

    1987-01-01

    Digital controllers are being developed for wind tunnel magnetic suspension and balance systems, which in turn permit wind tunnel testing of aircraft models free from support interference. Hardware and software features of two existing digital control systems are reviewed. Some aspects of model position sensing and system calibration are also discussed.

  8. 22 CFR 208.110 - What is the purpose of the nonprocurement debarment and suspension system?

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false What is the purpose of the nonprocurement debarment and suspension system? 208.110 Section 208.110 Foreign Relations AGENCY FOR INTERNATIONAL... the nonprocurement debarment and suspension system? (a) To protect the public interest, the Federal...

  9. Enhancement of aerobic biodegradation in an oxygen-limiting environment using a saponin-based microbubble suspension

    International Nuclear Information System (INIS)

    Choi, Yong Ju; Kim, Young-Jin; Nam, Kyoungphile

    2009-01-01

    This study investigated the ability of a saponin-based microbubble suspension to enhance aerobic biodegradation of phenanthrene by subsurface delivery. As the microbubble suspension flowed through a sand column pressure buildup and release was repeatedly observed, which delivered oxygen to the less permeable regions. Burkholderia cepacia RPH1, a phenanthrene-degrading bacterium, was mainly transported in a suspended form in the microbubble suspension. When three pore volumes of the microbubble suspension containing B. cepacia RPH1 was introduced into a column contaminated with phenanthrene (100 mg/kg), the oxygen content declined to 5% from an initial value of 20% within 5 days and correspondingly, 34.4% of initial phenanthrene was removed in 8 days. The addition of two further three pore volumes enhanced the biodegradation efficiency by a factor of 2.2. Our data suggest that a saponin-based microbubble suspension could be a potential carrier for enhancing the aerobic biodegradation under an oxygen-limiting environment. - Microbubble suspension can enhance the phenanthrene biodegradation under an oxygen-limiting condition.

  10. Enhancement of aerobic biodegradation in an oxygen-limiting environment using a saponin-based microbubble suspension

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yong Ju; Kim, Young-Jin [Department of Civil and Environmental Engineering, Seoul National University, Shillim-dong, Gwanak-gu, Seoul (Korea, Republic of); Nam, Kyoungphile, E-mail: kpnam@snu.ac.k [Department of Civil and Environmental Engineering, Seoul National University, Shillim-dong, Gwanak-gu, Seoul (Korea, Republic of)

    2009-08-15

    This study investigated the ability of a saponin-based microbubble suspension to enhance aerobic biodegradation of phenanthrene by subsurface delivery. As the microbubble suspension flowed through a sand column pressure buildup and release was repeatedly observed, which delivered oxygen to the less permeable regions. Burkholderia cepacia RPH1, a phenanthrene-degrading bacterium, was mainly transported in a suspended form in the microbubble suspension. When three pore volumes of the microbubble suspension containing B. cepacia RPH1 was introduced into a column contaminated with phenanthrene (100 mg/kg), the oxygen content declined to 5% from an initial value of 20% within 5 days and correspondingly, 34.4% of initial phenanthrene was removed in 8 days. The addition of two further three pore volumes enhanced the biodegradation efficiency by a factor of 2.2. Our data suggest that a saponin-based microbubble suspension could be a potential carrier for enhancing the aerobic biodegradation under an oxygen-limiting environment. - Microbubble suspension can enhance the phenanthrene biodegradation under an oxygen-limiting condition.

  11. Optimization of Automotive Suspension System by Design of Experiments: A Nonderivative Method

    Directory of Open Access Journals (Sweden)

    Anirban C. Mitra

    2016-01-01

    Full Text Available A lot of health issues like low back pain, digestive disorders, and musculoskeletal disorders are caused as a result of the whole body vibrations induced by automobiles. This paper is concerned with the enhancement and optimization of suspension performance by using factorial methods of Design of Experiments, a nonderivative method. It focuses on the optimization of ride comfort and determining the parameters which affect the suspension behavior significantly as per the guidelines stated in ISO 2631-1:1997 standards. A quarter car test rig integrated with a LabVIEW based data acquisition system was developed to understand the real time behavior of a vehicle. In the pilot experiment, only three primary suspension parameters, that is, spring-stiffness, damping, and sprung mass, were considered and the full factorial method was implemented for the purpose of optimization. But the regression analysis of the data obtained rendered a very low goodness of fit which indicated that other parameters are likely to influence the response. Subsequently, steering geometry angles, camber and toe and tire pressure, were included in the design. Fractional factorial method with six factors was implemented to optimize ride comfort. The resultant optimum combination was then verified on the test rig with high correlation.

  12. Design considerations for a semi-active electromagnetic suspension system

    NARCIS (Netherlands)

    Paulides, J.J.H.; Encica, L.; Lomonova, E.A.; Vandenput, A.J.A.

    2006-01-01

    Vehicle manufacturers always strive to improve the vehicle handling and passenger safety and comfort. One of the focus points for the automotive industry is the (semi-)active suspension system for which various commercial technologies are existing, varying from pneumatic to hydraulic. This paper

  13. Compressible Fluid Suspension Performance Testing

    National Research Council Canada - National Science Library

    Hoogterp, Francis

    2003-01-01

    ... compressible fluid suspension system that was designed and installed on the vehicle by DTI. The purpose of the tests was to evaluate the possible performance benefits of the compressible fluid suspension system...

  14. Processing of high performance composites based on peek by aqueous suspension prepregging

    Directory of Open Access Journals (Sweden)

    Liliana Burakowski Nohara

    2010-06-01

    Full Text Available The use of polyamic acid (PAA precursor as interphase in polymer composites is one of the many applications of polyimides (PIs. In this work, composites based on poly(ether-ether-ketone (PEEK and carbon fibers were prepared using two manufacturing techniques for thermoplastic composites: hot compression molding, and aqueous polymeric suspension prepregging using PIs as interphase. Two PAAs were synthesized and used as interphases: 3,3'-4,4'-benzophenonetetracarboxylic dianhydride/oxydianiline (BTDA/ODA and pyromellitic dianhydride/oxydianiline (PMDA/ODA. The PAA/PI systems were analyzed by differential scanning calorimetry (DSC, thermogravimetry (TGA, Fourier transform infrared spectroscopy (FTIR and nuclear magnetic resonance (NMR. Results from these analyses confirmed the synthesis of these compounds. Aqueous polymeric suspension prepregging was more efficient than hot compression molding when the PMDA/ODA PAA/PI interphase was used; also, the interlaminar shear strength of composites produced using this technique was 14.5% higher than the one produced using hot compression molding.

  15. Acid-base properties of the surface of the α-Al2O3 suspension

    Science.gov (United States)

    Ryazanov, M. A.; Dudkin, B. N.

    2009-12-01

    The distribution of the acid-base centers on the surface of α-Al2O3 suspension particles was studied by potentiometric titration, and the corresponding p K spectra were constructed. It was inferred that the double electric layer created by the supporting electrolyte substantially affected the screening of the acid-base centers on the particle surface of the suspension.

  16. Vehicle lateral dynamics stabilization using active suspension

    Directory of Open Access Journals (Sweden)

    Drobný V.

    2008-12-01

    Full Text Available The paper deals with the investigation of active nonlinear suspension control in order to stabilize the lateral vehicle motion in similar way as systems like ESP do. The lateral stabilization of vehicle based on braking forces can be alternatively provided by the different setting of suspension forces. The basis of this control is the nonlinear property of the tyres. The vehicle has at least four wheels and it gives one or more redundant vertical forces that can be used for the different distribution of vertical suspension forces in such a way that resulting lateral and/or longitudinal forces create the required correction moment for lateral dynamic vehicle stabilization.

  17. Optimization of Front Axle Suspension System of Articulated Dump Truck

    DEFF Research Database (Denmark)

    Langer, Thomas Heegaard; Christensen, Brian B.; Mouritsen, Ole Ø.

    2010-01-01

    that has been subjected to comfort improvement is a two axle articulated dump truck. The comfort has been in terms of whole body vibration exposure and the overall improvement has been made possible by adding front axle suspension. However, a hydraulic stabilizing system between the tractor and trailer...... to evaluate the whole body vibrations. By use of a multibody simulation model of the dump truck the whole body vibration exposure has been computed using the predefined work cycle as model input. The design parameters comprise the components of the hydraulic subsystem of the suspension, i.e., the size...

  18. Compact vibration isolation and suspension for Australian International Gravitational Observatory: Local control system

    Science.gov (United States)

    Dumas, Jean-Charles; Barriga, Pablo; Zhao, Chunnong; Ju, Li; Blair, David G.

    2009-11-01

    High performance vibration isolators are required for ground based gravitational wave detectors. To attain very high performance at low frequencies we have developed multistage isolators for the proposed Australian International Gravitational Observatory detector in Australia. New concepts in vibration isolation including self-damping, Euler springs, LaCoste springs, Roberts linkages, and double preisolation require novel sensors and actuators. Double preisolation enables internal feedback to be used to suppress low frequency seismic noise. Multidegree of freedom control systems are required to attain high performance. Here we describe the control components and control systems used to control all degrees of freedom. Feedback forces are injected at the preisolation stages and at the penultimate suspension stage. There is no direct actuation on test masses. A digital local control system hosted on a digital signal processor maintains alignment and position, corrects drifts, and damps the low frequency linear and torsional modes without exciting the very high Q-factor test mass suspension. The control system maintains an optical cavity locked to a laser with a high duty cycle even in the absence of an autoalignment system. An accompanying paper presents the mechanics of the system, and the optical cavity used to determine isolation performance. A feedback method is presented, which is expected to improve the residual motion at 1 Hz by more than one order of magnitude.

  19. Compact vibration isolation and suspension for Australian International Gravitational Observatory: local control system.

    Science.gov (United States)

    Dumas, Jean-Charles; Barriga, Pablo; Zhao, Chunnong; Ju, Li; Blair, David G

    2009-11-01

    High performance vibration isolators are required for ground based gravitational wave detectors. To attain very high performance at low frequencies we have developed multistage isolators for the proposed Australian International Gravitational Observatory detector in Australia. New concepts in vibration isolation including self-damping, Euler springs, LaCoste springs, Roberts linkages, and double preisolation require novel sensors and actuators. Double preisolation enables internal feedback to be used to suppress low frequency seismic noise. Multidegree of freedom control systems are required to attain high performance. Here we describe the control components and control systems used to control all degrees of freedom. Feedback forces are injected at the preisolation stages and at the penultimate suspension stage. There is no direct actuation on test masses. A digital local control system hosted on a digital signal processor maintains alignment and position, corrects drifts, and damps the low frequency linear and torsional modes without exciting the very high Q-factor test mass suspension. The control system maintains an optical cavity locked to a laser with a high duty cycle even in the absence of an autoalignment system. An accompanying paper presents the mechanics of the system, and the optical cavity used to determine isolation performance. A feedback method is presented, which is expected to improve the residual motion at 1 Hz by more than one order of magnitude.

  20. System concept definition of the Grumman superconducting Electromagnetic Suspension (EMS) Maglev design

    Science.gov (United States)

    Proise, M.

    1994-01-01

    Grumman, under contract to the Army Corps of Engineers, completed a System Concept Definition (SCD) study to design a high-speed 134 m/s (300 m.p.h.) magnetically levitated (Maglev) transportation system. The primary development goals were to design a Maglev that is safe, reliable, environmentally acceptable, and low-cost. The cost issue was a predominant one, since previous studies have shown that an economically viable Maglev system (one that is attractive to investors for future models of passenger and/or freight transportation) requires a cost that is about $12.4 M/km ($20 Million per mile). The design is based on the electromagnetic suspension (EMS) system using superconducting iron-core magnets mounted along both sides of the vehicle. The EMS system has several advantages compared to the electrodynamic suspension (EDS) Maglev systems such as low stray magnetic fields in the passenger cabin and the surrounding areas, uniform load distribution along the full length of the vehicle, and small pole pitch for smoother propulsion and ride comfort. It is also levitated at all speeds and incorporates a wrap-around design of safer operation. The Grumman design has all the advantages of an EMS system identified above, while eliminating (or significantly improving) drawbacks associated with normal magnet powered EMS systems. Improvements include larger gap clearance, lighter weight, lower number of control servos, and higher off line switching speeds. The design also incorporates vehicle tilt (plus or minus 9 deg) for higher coordinated turn and turn out speed capability.

  1. Design aspects of an active electromagnetic suspension system for automotive applications

    NARCIS (Netherlands)

    Gysen, B.L.J.; Janssen, J.L.G.; Paulides, J.J.H.; Lomonova, E.A.

    2008-01-01

    This paper is concerned with the design aspects of an active electromagnet suspension system for automotive applications which combines a brushless tubular permanent magnet actuator (TPMA) with a passive spring. This system provides for additional stability and safety by performing active roll and

  2. Design aspects of an active electromagnetic suspension system for automotive applications

    NARCIS (Netherlands)

    Gysen, B.L.J.; Janssen, J.L.G.; Paulides, J.J.H.; Lomonova, E.

    2009-01-01

    This paper is concerned with the design aspects of an active electromagnet suspension system for automotive applications which combines a brushless tubular permanent-magnet actuator with a passive spring. This system provides for additional stability and safety by performing active roll and pitch

  3. Inkjet printable nanosilver suspensions for enhanced sintering quality in rapid manufacturing

    International Nuclear Information System (INIS)

    Bai, John G; Creehan, Kevin D; Kuhn, Howard A

    2007-01-01

    Inkjet printable nanosilver suspensions were prepared by dispersing 30 nm silver particles into a water-based binder system to enhance the sintering quality in rapid manufacturing. During three-dimensional printing (3DP), the nanosilver suspensions were inkjet printed onto repetitively spread microsilver powder for selective joining. Since the nanosilver particles in the suspensions can be sintered at relatively low temperatures to bond the neighbouring microsilver powder, they were used to provide the continuous bonding strength of the manufacturing parts during the heat-up procedure of the sintering operation. Comparative study shows that the silver parts printed using the nanosilver suspension were significantly enhanced in sintering quality than those printed using the binder system, especially when the silver parts had thin or small features with high aspect ratios

  4. Adaptive Hybrid Control of Vehicle Semiactive Suspension Based on Road Profile Estimation

    Directory of Open Access Journals (Sweden)

    Yechen Qin

    2015-01-01

    Full Text Available A new road estimation based suspension hybrid control strategy is proposed. Its aim is to adaptively change control gains to improve both ride comfort and road handling with the constraint of rattle space. To achieve this, analytical expressions for ride comfort, road handling, and rattle space with respect to road input are derived based on the hybrid control, and the problem is transformed into a MOOP (Multiobjective Optimization Problem and has been solved by NSGA-II (Nondominated Sorting Genetic Algorithm-II. A new road estimation and classification method, which is based on ANFIS (Adaptive Neurofuzzy Inference System and wavelet transforms, is then presented as a means of detecting the road profile level, and a Kalman filter is designed for observing unknown states. The results of simulations conducted with random road excitation show that the efficiency of the proposed control strategy compares favourably to that of a passive system.

  5. Nanofluid bioconvection in water-based suspensions containing nanoparticles and oxytactic microorganisms: oscillatory instability

    Directory of Open Access Journals (Sweden)

    Kuznetsov Andrey

    2011-01-01

    Full Text Available Abstract The aim of this article is to propose a novel type of a nanofluid that contains both nanoparticles and motile (oxytactic microorganisms. The benefits of adding motile microorganisms to the suspension include enhanced mass transfer, microscale mixing, and anticipated improved stability of the nanofluid. In order to understand the behavior of such a suspension at the fundamental level, this article investigates its stability when it occupies a shallow horizontal layer. The oscillatory mode of nanofluid bioconvection may be induced by the interaction of three competing agencies: oxytactic microorganisms, heating or cooling from the bottom, and top or bottom-heavy nanoparticle distribution. The model includes equations expressing conservation of total mass, momentum, thermal energy, nanoparticles, microorganisms, and oxygen. Physical mechanisms responsible for the slip velocity between the nanoparticles and the base fluid, such as Brownian motion and thermophoresis, are accounted for in the model. An approximate analytical solution of the eigenvalue problem is obtained using the Galerkin method. The obtained solution provides important physical insights into the behavior of this system; it also explains when the oscillatory mode of instability is possible in such system.

  6. Determination of Weight Suspension Rigidity in the Transport-Erector Aggregates

    Directory of Open Access Journals (Sweden)

    V. A. Zverev

    2016-01-01

    Full Text Available The aim is to determine weight suspension rigidity in aggregates designed to perform technological transport-erector operations at the miscellaneous launch complexes.We consider the weight suspension comprising the following distinctive structural components: the executive weight-lowering mechanism, polyspast mechanism, rope, traverse, and rods. A created structural dynamic model of suspension allowed us to define weight suspension rigidity. Within the framework of design analysis of a dynamic model we determined the rigidity of its structural units, i.e. traverse, rope, and polyspast.Known analytical relationships were used to calculate the rope rigidity. To determine rigidity of polyspast and traverse have been created special models based on the finite element method. For each model deformation in the specific points under the test load have been defined. Data obtained were used to determine trigidity of traverses and polyspast, and also rigidity of suspension in total. The rigidity models of polispast mechanism and traverse have been developed and calculated using the software complex "Zenit-95".As the research results, the paper presents a dynamic model of the weight suspension of the transport-erector aggregate, the finite element models of the polispast mechanism and traverse, an algorithm for determining the weight suspension rigidity and relevant analytical relationships.Independent calculation of weight suspension rigidity enables us to simplify further dynamic calculation of the aggregate-weight system because it allows attaining a simpler model of the aggregate-weight system that uses the weight suspension model as an element of equivalent rigidity. Despite this simplification the model allows us to determine correctly weight movement parameters and overloads in the aggregate-weight system in the process of technical operations.

  7. Dynamic model and workspace analysis of novel incompletely restrained cable-suspension swing system driven by two cables

    Directory of Open Access Journals (Sweden)

    Naige Wang

    2017-03-01

    Full Text Available The incompletely restrained cable-suspension swing system driven by two cables is introduced in this article. Based on wrench of forces theory and Lagrange’s equation of first kind, the static and dynamics models of incompletely restrained cable-suspension swing system driven by two cables are established, respectively. In order to obtain an intuitive understanding of the trajectory analysis, a dynamics model consisting of governing equation and geometric constraint conditions which is a set of the mixed differential-algebraic equation in mathematics is established. A typical feedback controller and an inverse model were set up to estimate the driving function. The effective workspace, which is used to guarantee an efficient swing process, mostly depends on the geometrical shape rather than the volume itself which was calculated by trajectory analysis. In order to estimate system features and ensure a limited range of tension in underconstrained spatial cable system, the probable location of unbalanced loading was evaluated by pointwise evaluation techniques during normal work.

  8. Disturbance observer based Takagi-Sugeno fuzzy control for an active seat suspension

    Science.gov (United States)

    Ning, Donghong; Sun, Shuaishuai; Zhang, Fei; Du, Haiping; Li, Weihua; Zhang, Bangji

    2017-09-01

    In this paper, a disturbance observer based Takagi-Sugeno (TS) fuzzy controller is proposed for an active seat suspension; both simulations and experiments have been performed verifying the performance enhancement and stability of the proposed controller. The controller incorporates closed-loop feedback control using the measured acceleration of the seat and deflection of the suspension; these two variables can be easily measured in practical applications, thus allowing the proposed controller to be robust and adaptable. A disturbance observer that can estimate the disturbance caused by friction, model simplification, and controller output error has also been used to compensate a H∞ state feedback controller. The TS fuzzy control method is applied to enhance the controller's performance by considering the variation of driver's weight during operation. The vibration of a heavy duty vehicle seat is largest in the frequency range between 2 Hz and 4 Hz, in the vertical direction; therefore, it is reasonable to focus on controlling low frequency vibration amplitudes and maintain the seat suspensions passivity at high frequency. Moreover, both the simulation and experimental results show that the active seat suspension with the proposed controller can effectively isolate unwanted vibration amplitudes below 4.5 Hz, when compared with a well-tuned passive seat suspension. The active controller has been further validated under bump and random road tests with both a 55 kg and a 70 kg loads. The bump road test demonstrated the controller has good transient response capabilities. The random road test result has been presented both in the time domain and the frequency domain. When with the above two loads, the controlled seat suspensions root-mean-square (RMS) accelerations were reduced by 45.5% and 49.5%, respectively, compared with a well-tuned passive seat suspension. The proposed active seat suspension controller has great potential and is very practical for application

  9. Motion control of a large gap magnetic suspension system for microrobotic manipulation

    Energy Technology Data Exchange (ETDEWEB)

    Craig, David; Khamesee, Mir Behrad [Department of Mechanical and Mechatronics Engineering, University of Waterloo, Ontario, N2L 3G1 (Canada)

    2007-06-07

    Magnetic suspension systems have shown a great deal of promise in the field of microrobotics. This paper discusses the performance of a new large gap magnetic suspension system developed by the researchers. The magnetic drive unit consists of six electromagnets attached to a soft iron pole piece and yoke. Levitation of an 11.19 g microrobot prototype is demonstrated for step, ramp and periodic input trajectories using PID control. The working envelope of the microrobot is 30 x 22 x 20 mm{sup 3}, with an RMS error on the order of 18 {mu}m in the vertical direction and 8 {mu}m in the horizontal direction. It is demonstrated that the levitated microrobot is able to track the desired trajectory precisely and that the system has potential application for micromanipulation.

  10. Motion control of a large gap magnetic suspension system for microrobotic manipulation

    International Nuclear Information System (INIS)

    Craig, David; Khamesee, Mir Behrad

    2007-01-01

    Magnetic suspension systems have shown a great deal of promise in the field of microrobotics. This paper discusses the performance of a new large gap magnetic suspension system developed by the researchers. The magnetic drive unit consists of six electromagnets attached to a soft iron pole piece and yoke. Levitation of an 11.19 g microrobot prototype is demonstrated for step, ramp and periodic input trajectories using PID control. The working envelope of the microrobot is 30 x 22 x 20 mm 3 , with an RMS error on the order of 18 μm in the vertical direction and 8 μm in the horizontal direction. It is demonstrated that the levitated microrobot is able to track the desired trajectory precisely and that the system has potential application for micromanipulation

  11. Coupling Mechanism and Decoupled Suspension Control Model of a Half Car

    Directory of Open Access Journals (Sweden)

    Hailong Zhang

    2016-01-01

    Full Text Available A structure decoupling control strategy of half-car suspension is proposed to fully decouple the system into independent front and rear quarter-car suspensions in this paper. The coupling mechanism of half-car suspension is firstly revealed and formulated with coupled damping force (CDF in a linear function. Moreover, a novel dual dampers-based controllable quarter-car suspension structure is proposed to realize the independent control of pitch and vertical motions of the half car, in which a newly added controllable damper is suggested to be installed between the lower control arm and connection rod in conventional quarter-car suspension structure. The suggested damper constantly regulates the half-car pitch motion posture in a smooth and steady operation condition meantime achieving the expected completely structure decoupled control of the half-car suspension, by compensating the evolved CDF.

  12. Viscosity of aqueous and cyanate ester suspensions containing alumina nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Lawler, Katherine [Iowa State Univ., Ames, IA (United States)

    2009-01-01

    The viscosities of both aqueous and cyanate ester monomer (BECy) based suspensions of alumina nanoparticle were studied. The applications for these suspensions are different: aqueous suspensions of alumina nanoparticles are used in the production of technical ceramics made by slip casting or tape casting, and the BECy based suspensions are being developed for use in an injection-type composite repair resin. In the case of aqueous suspensions, it is advantageous to achieve a high solids content with low viscosity in order to produce a high quality product. The addition of a dispersant is useful so that higher solids content suspensions can be used with lower viscosities. For BECy suspensions, the addition of nanoparticles to the BECy resin is expected to enhance the mechanical properties of the cured composite. The addition of saccharides to aqueous suspensions leads to viscosity reduction. Through DSC measurements it was found that the saccharide molecules formed a solution with water and this resulted in lowering the melting temperature of the free water according to classic freezing point depression. Saccharides also lowered the melting temperature of the bound water, but this followed a different rule. The shear thinning and melting behaviors of the suspensions were used to develop a model based on fractal-type agglomeration. It is believed that the structure of the particle flocs in these suspensions changes with the addition of saccharides which leads to the resultant viscosity decrease. The viscosity of the BECy suspensions increased with solids content, and the viscosity increase was greater than predicted by the classical Einstein equation for dilute suspensions. Instead, the Mooney equation fits the viscosity behavior well from 0-20 vol% solids. The viscosity reduction achieved at high particle loadings by the addition of benzoic acid was also investigated by NMR. It appears that the benzoic acid interacts with the surface of the alumina particle which may

  13. Adaptive neural networks control for camera stabilization with active suspension system

    Directory of Open Access Journals (Sweden)

    Feng Zhao

    2015-08-01

    Full Text Available The camera always suffers from image instability on the moving vehicle due to unintentional vibrations caused by road roughness. This article presents an adaptive neural network approach mixed with linear quadratic regulator control for a quarter-car active suspension system to stabilize the image captured area of the camera. An active suspension system provides extra force through the actuator which allows it to suppress vertical vibration of sprung mass. First, to deal with the road disturbance and the system uncertainties, radial basis function neural network is proposed to construct the map between the state error and the compensation component, which can correct the optimal state-feedback control law. The weights matrix of radial basis function neural network is adaptively tuned online. Then, the closed-loop stability and asymptotic convergence performance is guaranteed by Lyapunov analysis. Finally, the simulation results demonstrate that the proposed controller effectively suppresses the vibration of the camera and enhances the stabilization of the entire camera, where different excitations are considered to validate the system performance.

  14. Geometric nonlinear analysis of self-anchored cable-stayed suspension bridges.

    Science.gov (United States)

    Hui-Li, Wang; Yan-Bin, Tan; Si-Feng, Qin; Zhe, Zhang

    2013-01-01

    Geometric nonlinearity of self-anchored cable-stayed suspension bridges is studied in this paper. The repercussion of shrinkage and creep of concrete, rise-to-span ratio, and girder camber on the system is discussed. A self-anchored cable-stayed suspension bridge with a main span of 800 m is analyzed with linear theory, second-order theory, and nonlinear theory, respectively. In the condition of various rise-to-span ratios and girder cambers, the moments and displacements of both the girder and the pylon under live load are acquired. Based on the results it is derived that the second-order theory can be adopted to analyze a self-anchored cable-stayed suspension bridge with a main span of 800 m, and the error is less than 6%. The shrinkage and creep of concrete impose a conspicuous impact on the structure. And it outmatches suspension bridges for system stiffness. As the rise-to-span ratio increases, the axial forces of the main cable and the girder decline. The system stiffness rises with the girder camber being employed.

  15. Geometric Nonlinear Analysis of Self-Anchored Cable-Stayed Suspension Bridges

    Directory of Open Access Journals (Sweden)

    Wang Hui-Li

    2013-01-01

    Full Text Available Geometric nonlinearity of self-anchored cable-stayed suspension bridges is studied in this paper. The repercussion of shrinkage and creep of concrete, rise-to-span ratio, and girder camber on the system is discussed. A self-anchored cable-stayed suspension bridge with a main span of 800 m is analyzed with linear theory, second-order theory, and nonlinear theory, respectively. In the condition of various rise-to-span ratios and girder cambers, the moments and displacements of both the girder and the pylon under live load are acquired. Based on the results it is derived that the second-order theory can be adopted to analyze a self-anchored cable-stayed suspension bridge with a main span of 800 m, and the error is less than 6%. The shrinkage and creep of concrete impose a conspicuous impact on the structure. And it outmatches suspension bridges for system stiffness. As the rise-to-span ratio increases, the axial forces of the main cable and the girder decline. The system stiffness rises with the girder camber being employed.

  16. Solution or suspension - Does it matter for lipid based systems? In vivo studies of chase dosing lipid vehicles with aqueous suspensions of a poorly soluble drug.

    Science.gov (United States)

    Larsen, A T; Holm, R; Müllertz, A

    2017-08-01

    In this study, the potential of co-administering an aqueous suspension with a placebo lipid vehicle, i.e. chase dosing, was investigated in rats relative to the aqueous suspension alone or a solution of the drug in the lipid vehicle. The lipid investigated in the present study was Labrafil M2125CS and three evaluated poorly soluble model compounds, danazol, cinnarizine and halofantrine. For cinnarizine and danazol the oral bioavailability in rats after chase dosing or dosing the compound dissolved in Labrafil M21515CS was similar and significantly higher than for the aqueous suspension. For halofantrine the chase dosed group had a tendency towards a low bioavailability relative to the Labrafil M2125CS solution, but still a significant higher bioavailability relative to the aqueous suspension. This could be due to factors such as a slower dissolution rate in the intestinal phase of halofantrine or a lower solubility in the colloidal structures formed during digestion, but other mechanisms may also be involved. The study thereby supported the potential of chase dosing as a potential dosing regimen in situations where it is beneficial to have a drug in the solid state, e.g. due to chemical stability issues in the lipid vehicle. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Dynamic analysis of suspension cable based on vector form intrinsic finite element method

    Science.gov (United States)

    Qin, Jian; Qiao, Liang; Wan, Jiancheng; Jiang, Ming; Xia, Yongjun

    2017-10-01

    A vector finite element method is presented for the dynamic analysis of cable structures based on the vector form intrinsic finite element (VFIFE) and mechanical properties of suspension cable. Firstly, the suspension cable is discretized into different elements by space points, the mass and external forces of suspension cable are transformed into space points. The structural form of cable is described by the space points at different time. The equations of motion for the space points are established according to the Newton’s second law. Then, the element internal forces between the space points are derived from the flexible truss structure. Finally, the motion equations of space points are solved by the central difference method with reasonable time integration step. The tangential tension of the bearing rope in a test ropeway with the moving concentrated loads is calculated and compared with the experimental data. The results show that the tangential tension of suspension cable with moving loads is consistent with the experimental data. This method has high calculated precision and meets the requirements of engineering application.

  18. Research on magnetorheological damper suspension with permanent magnet and magnetic valve based on developed FOA-optimal control algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Ping; Gao, Hong [Anhui Polytechnic University, Wuhu (China); Niu, Limin [Anhui University of Technology, Maanshan (China)

    2017-07-15

    Due to the fail safe problem, it was difficult for the existing Magnetorheological damper (MD) to be widely applied in automotive suspensions. Therefore, permanent magnets and magnetic valves were introduced to existing MDs so that fail safe problem could be solved by the magnets and damping force could be adjusted easily by the magnetic valve. Thus, a new Magnetorheological damper with permanent magnet and magnetic valve (MDPMMV) was developed and MDPMMV suspension was studied. First of all, mechanical structure of existing magnetorheological damper applied in automobile suspensions was redesigned, comprising a permanent magnet and a magnetic valve. In addition, prediction model of damping force was built based on electromagnetics theory and Bingham model. Experimental research was onducted on the newly designed damper and goodness of fit between experiment results and simulated ones by models was high. On this basis, a quarter suspension model was built. Then, fruit Fly optimization algorithm (FOA)-optimal control algorithm suitable for automobile suspension was designed based on developing normal FOA. Finally, simulation experiments and bench tests with input surface of pulse road and B road were carried out and the results indicated that working erformance of MDPMMV suspension based on FOA-optimal control algorithm was good.

  19. Vibration control of an energy regenerative seat suspension with variable external resistance

    Science.gov (United States)

    Ning, Donghong; Sun, Shuaishuai; Du, Haiping; Li, Weihua; Zhang, Nong

    2018-06-01

    In this paper, an energy regenerative seat suspension with a variable external resistance is proposed and built, and a semi-active controller for its vibration control is also designed and validated. The energy regenerative seat suspension is built with a three-phase generator and a gear reducer, which are installed in the scissors structure centre of the seat suspension, and the vibration energy is directly harvested from the rotary movement of suspension's scissors structure. The electromagnetic torque of the semi-active seat suspension actuator is controlled by an external variable resistor. An integrated model including the seat suspension's kinematics and the generator is built and proven to match the test result very well. A simplified experimental phenomenon model is also built based on the test results for the controller design. A state feedback H∞ controller is proposed for the regenerative seat suspension's semi-active vibration control. The proposed regenerative seat suspension and its controller are validated with both simulations and experiments. A well-tuned passive seat suspension is applied to evaluate the regenerative seat's performance. Based on ISO 2631-1, the frequency-weighted root mean square (FW-RMS) acceleration of the proposed seat suspension has a 22.84% reduction when compared with the passive one, which indicates the improvement of ride comfort. At the same time, the generated RMS power is 1.21 W. The proposed regenerative seat suspension can greatly improve the driver's ride comfort and has the potential to be developed to a self-powered semi-active system.

  20. Establishment of Aquilaria malaccensis Callus, cell suspension and adventitious root systems

    International Nuclear Information System (INIS)

    Norazlina Noordin; Rusli Ibrahim

    2010-01-01

    Aquilaria malaccensis is a tropical forest tree from the family Thymelaeaceae, an endangered forest species and was listed in CITES since 1995. Locally known as Pokok Karas, this tree produces agar wood or gaharu, a highly valuable, resinous and fragrant forest product. Karas has been highly recognized for its vast medicinal values and gaharu has been widely use for perfumery, incense and religious purposes. The phyto chemical studies of agar wood showed that Sesqui terpenoid and Phenyl ethy chromone derivatives are the principal compounds that have anti allergic and anti microbe activities. Cell and organ culture systems provide large scale production of biomass and offers feasibilities for the production of secondary metabolites. This paper describes the work done for establishing reproducible systems for callus initiation and production of cell suspension cultures as well as production of adventitious roots that will later be amenable for the production of secondary metabolites of A. malaccensis. Hence, further manipulation with Methyl Jasmonate, a chemical elicitor could be done to induce secondary metabolites using callus, cell suspension and adventitious roots systems. (author)

  1. Motion stability of high-speed maglev systems in consideration of aerodynamic effects: a study of a single magnetic suspension system

    Science.gov (United States)

    Wu, Han; Zeng, Xiao-Hui; Yu, Yang

    2017-12-01

    In this study, the intrinsic mechanism of aerodynamic effects on the motion stability of a high-speed maglev system was investigated. The concept of a critical speed for maglev vehicles considering the aerodynamic effect is proposed. The study was carried out based on a single magnetic suspension system, which is convenient for proposing relevant concepts and obtaining explicit expressions. This study shows that the motion stability of the suspension system is closely related to the vehicle speed when aerodynamic effects are considered. With increases of the vehicle speed, the stability behavior of the system changes. At a certain vehicle speed, the stability of the system reaches a critical state, followed by instability. The speed corresponding to the critical state is the critical speed. Analysis reveals that when the system reaches the critical state, it takes two forms, with two critical speeds, and thus two expressions for the critical speed are obtained. The conditions of the existence of the critical speed were determined, and the effects of the control parameters and the lift coefficient on the critical speed were analyzed by numerical analysis. The results show that the first critical speed appears when the aerodynamic force is upward, and the second critical speed appears when the aerodynamic force is downward. Moreover, both critical speeds decrease with the increase of the lift coefficient.

  2. Robustness analysis of bogie suspension components Pareto optimised values

    Science.gov (United States)

    Mousavi Bideleh, Seyed Milad

    2017-08-01

    Bogie suspension system of high speed trains can significantly affect vehicle performance. Multiobjective optimisation problems are often formulated and solved to find the Pareto optimised values of the suspension components and improve cost efficiency in railway operations from different perspectives. Uncertainties in the design parameters of suspension system can negatively influence the dynamics behaviour of railway vehicles. In this regard, robustness analysis of a bogie dynamics response with respect to uncertainties in the suspension design parameters is considered. A one-car railway vehicle model with 50 degrees of freedom and wear/comfort Pareto optimised values of bogie suspension components is chosen for the analysis. Longitudinal and lateral primary stiffnesses, longitudinal and vertical secondary stiffnesses, as well as yaw damping are considered as five design parameters. The effects of parameter uncertainties on wear, ride comfort, track shift force, stability, and risk of derailment are studied by varying the design parameters around their respective Pareto optimised values according to a lognormal distribution with different coefficient of variations (COVs). The robustness analysis is carried out based on the maximum entropy concept. The multiplicative dimensional reduction method is utilised to simplify the calculation of fractional moments and improve the computational efficiency. The results showed that the dynamics response of the vehicle with wear/comfort Pareto optimised values of bogie suspension is robust against uncertainties in the design parameters and the probability of failure is small for parameter uncertainties with COV up to 0.1.

  3. Mathematical models for suspension bridges nonlinear structural instability

    CERN Document Server

    Gazzola, Filippo

    2015-01-01

    This work provides a detailed and up-to-the-minute survey of the various stability problems that can affect suspension bridges. In order to deduce some experimental data and rules on the behavior of suspension bridges, a number of historical events are first described, in the course of which several questions concerning their stability naturally arise. The book then surveys conventional mathematical models for suspension bridges and suggests new nonlinear alternatives, which can potentially supply answers to some stability questions. New explanations are also provided, based on the nonlinear structural behavior of bridges. All the models and responses presented in the book employ the theory of differential equations and dynamical systems in the broader sense, demonstrating that methods from nonlinear analysis can allow us to determine the thresholds of instability.

  4. A computational model of the cognitive impact of decorative elements on the perception of suspense

    Science.gov (United States)

    Delatorre, Pablo; León, Carlos; Gervás, Pablo; Palomo-Duarte, Manuel

    2017-10-01

    Suspense is a key narrative issue in terms of emotional gratification, influencing the way in which the audience experiences a story. Virtually all narrative media uses suspense as a strategy for reader engagement regardless of the technology or genre. Being such an important narrative component, computational creativity has tackled suspense in a number of automatic storytelling. These systems are mainly based on narrative theories, and in general lack a cognitive approach involving the study of empathy or emotional effect of the environment impact. With this idea in mind, this paper reports on a computational model of the influence of decorative elements on suspense. It has been developed as part of a more general proposal for plot generation based on cognitive aspects. In order to test and parameterise the model, an evaluation based on textual stories and an evaluation based on a 3D virtual environment was run. In both cases, results suggest a direct influence of emotional perception of decorative objects in the suspense of a scene.

  5. Enabling high-rate electrochemical flow capacitors based on mesoporous carbon microspheres suspension electrodes

    Science.gov (United States)

    Tian, Meng; Sun, Yueqing; Zhang, Chuanfang (John); Wang, Jitong; Qiao, Wenming; Ling, Licheng; Long, Donghui

    2017-10-01

    Electrochemical flow capacitor (EFC) is a promising technology for grid energy storage, which combines the fast charging/discharging capability of supercapacitors with the scalable energy capacity of flow batteries. In this study, we report a high-power-density EFC using mesoporous carbon microspheres (MCMs) as suspension electrodes. By using a simple yet effective spray-drying technique, monodispersed MCMs with average particle size of 5 μm, high BET surface area of 1150-1267 m2 g-1, large pore volume of 2-4 cm3 g-1 and controllable mesopore size of 7-30 nm have been successfully prepared. The resultant MCMs suspension electrode shows excellent stability and considerable high capacitance of 100 F g-1 and good cycling ability (86% of initial capacitance after 10000 cycles). Specially, the suspension electrode exhibits excellent rate performance with 75% capacitance retention from 2 to 100 mV s-1, significantly higher than that of microporous carbon electrodes (20∼30%), due to the developed mesoporous channels facilitating for rapid ion diffusion. In addition, the electrochemical responses on both negative and positive suspension electrodes are studied, based on which an optimal capacitance matching between them is suggested for large-scale EFC unit.

  6. An Ultra-low Frequency Modal Testing Suspension System for High Precision Air Pressure Control

    Directory of Open Access Journals (Sweden)

    Qiaoling YUAN

    2014-05-01

    Full Text Available As a resolution for air pressure control challenges in ultra-low frequency modal testing suspension systems, an incremental PID control algorithm with dead band is applied to achieve high-precision pressure control. We also develop a set of independent hardware and software systems for high-precision pressure control solutions. Taking control system versatility, scalability, reliability, and other aspects into considerations, a two-level communication employing Ethernet and CAN bus, is adopted to complete such tasks as data exchange between the IPC, the main board and the control board ,and the pressure control. Furthermore, we build a single set of ultra-low frequency modal testing suspension system and complete pressure control experiments, which achieve the desired results and thus confirm that the high-precision pressure control subsystem is reasonable and reliable.

  7. V-TECS Guide for Auto Mechanics: Suspension Systems, Brakes and Steering.

    Science.gov (United States)

    Moore, Charles G.; And Others

    The materials in this document are an extension of a catalog of occupational duties, tasks, and performance objectives relevant to maintaining automotive suspension systems, brakes, and steering mechanisms. This document provides the following for each occupational task within each duty: (1) a standard of performance; (2) the conditions under…

  8. AUTOMOTIVE DIESEL MAINTENANCE 1. UNIT XXI, I--MAINTAINING THE AIR SYSTEM--CATERPILLAR DIESEL ENGINE, II--UNDERSTANDING REAR END SUSPENSION.

    Science.gov (United States)

    Minnesota State Dept. of Education, St. Paul. Div. of Vocational and Technical Education.

    THIS MODULE OF A 30-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF THE OPERATION AND MAINTENANCE OF THE DIESEL ENGINE AIR SYSTEM AND REAR AXLE SUSPENSION USED ON DIESEL POWERED VEHICLES. TOPICS ARE (1) AIR INDUCTION AND EXHAUST SYSTEM, (2) VALVE MECHANISM, (3) TROUBLESHOOTING THE AIR SYSTEM, (4) PURPOSE OF VEHICLE SUSPENSION, (5) TANDEM…

  9. Equivalent Air Spring Suspension Model for Quarter-Passive Model of Passenger Vehicles.

    Science.gov (United States)

    Abid, Haider J; Chen, Jie; Nassar, Ameen A

    2015-01-01

    This paper investigates the GENSIS air spring suspension system equivalence to a passive suspension system. The SIMULINK simulation together with the OptiY optimization is used to obtain the air spring suspension model equivalent to passive suspension system, where the car body response difference from both systems with the same road profile inputs is used as the objective function for optimization (OptiY program). The parameters of air spring system such as initial pressure, volume of bag, length of surge pipe, diameter of surge pipe, and volume of reservoir are obtained from optimization. The simulation results show that the air spring suspension equivalent system can produce responses very close to the passive suspension system.

  10. Mirror suspension system for the TAMA SAS

    CERN Document Server

    Takamori, A; Bertolini, A; Cella, G; DeSalvo, R; Fukushima, M; Iida, Y; Jacquier, F; Kawamura, S; Marka, S; Nishi, Y; Numata, K; Sannibale, V; Somiya, K; Takahashi, R; Tariq, H; Tsubono, K; Ugas, J; Viboud, N; Yamamoto, H; Yoda, T; Wang Chen Yang

    2002-01-01

    Several R and D programmes are ongoing to develop the next generation of interferometric gravitational wave detectors providing the superior sensitivity desired for refined astronomical observations. In order to obtain a wide observation band at low frequencies, the optics need to be isolated from the seismic noise. The TAMA SAS (seismic attenuation system) has been developed within an international collaboration between TAMA, LIGO, and some European institutes, with the main objective of achieving sufficient low-frequency seismic attenuation (-180 dB at 10 HZ). The system suppresses seismic noise well below the other noise levels starting at very low frequencies above 10 Hz. It also includes an active inertial damping system to decrease the residual motion of the optics enough to allow a stable operation of the interferometer. The TAMA SAS also comprises a sophisticated mirror suspension subsystem (SUS). The SUS provides support for the optics and vibration isolation complementing the SAS performance. The SU...

  11. Numerical simulation of shock absorbers heat load for semi-active vehicle suspension system

    Directory of Open Access Journals (Sweden)

    Demić Miroslav D.

    2016-01-01

    Full Text Available Dynamic simulation, based on modelling, has a significant role during to the process of vehicle development. It is especially important in the first design stages, when relevant parameters are to be defined. Shock absorber, as an executive part of a semi-active suspension system, is exposed to thermal loads which can lead to its damage and degradation of characteristics. Therefore, this paper attempts to analyze a conversion of mechanical work into heat energy by use of a method of dynamic simulation. The issue of heat dissipation from the shock absorber has not been taken into consideration.

  12. Microfluidic Fabrication Solutions for Tailor-Designed Fiber Suspensions

    Directory of Open Access Journals (Sweden)

    Helene Berthet

    2016-11-01

    Full Text Available Fibers are widely used in different industrial processes, for example in paper manufacturing or lost circulation problems in the oil industry. Recently, interest towards the use of fibers at the microscale has grown, driven by research in bio-medical applications or drug delivery systems. Microfluidic systems are not only directly relevant for lab-on-chip applications, but have also proven to be good model systems to tackle fundamental questions about the flow of fiber suspensions. It has therefore become necessary to provide fiber-like particles with an excellent control of their properties. We present here two complementary in situ methods to fabricate controlled micro-fibers allowing for an embedded fabrication and flow-on-a-chip platform. The first one, based on a photo-lithography principle, can be used to make isolated fibers and dilute fiber suspensions at specific locations of interest inside a microchannel. The self-assembly property of super-paramagnetic colloids is the principle of the second fabrication method, which enables the fabrication of concentrated suspensions of more flexible fibers. We propose a flow gallery with several examples of fiber flow illustrating the two methods’ capabilities and a range of recent laminar flow results.

  13. The effects of suction and pin/lock suspension systems on transtibial amputees' gait performance.

    Directory of Open Access Journals (Sweden)

    Hossein Gholizadeh

    Full Text Available BACKGROUND: The suction sockets that are commonly prescribed for transtibial amputees are believed to provide a better suspension than the pin/lock systems. Nevertheless, their effect on amputees' gait performance has not yet been fully investigated. The main intention of this study was to understand the potential effects of the Seal-in (suction and the Dermo (pin/lock suspension systems on amputees' gait performance. METHODOLOGY/PRINCIPAL FINDINGS: Ten unilateral transtibial amputees participated in this prospective study, and two prostheses were fabricated for each of them. A three-dimensional motion analysis system was used to evaluate the temporal-spatial, kinematics and kinetics variables during normal walking. We also asked the participants to complete some part of Prosthesis Evaluation Questionnaire (PEQ regarding their satisfaction and problems with both systems. The results revealed that there was more symmetry in temporal-spatial parameters between the prosthetic and sound limbs using the suction system. However, the difference between two systems was not significant (p<0.05. Evaluation of kinetic data and the subjects' feedback showed that the participants had more confidence using the suction socket and the sockets were more fit for walking. Nevertheless, the participants had more complaints with this system due to the difficulty in donning and doffing. CONCLUSION: It can be concluded that even though the suction socket could create better suspension, fit, and gait performance, overall satisfaction was higher with the pin/lock system due to easy donning and doffing of the prosthesis. TRIAL REGISTRATION: irct.ir IRCT2014012816395N1.

  14. High angle of attack position sensing for the Southampton University magnetic suspension and balance system

    Science.gov (United States)

    Parker, David H.

    1987-01-01

    An all digital five channel position detection system is to be installed in the Southampton University Magnetic Suspension and Balance System (SUMSBS). The system is intended to monitor a much larger range of model pitch attitudes than has been possible hitherto, up to a maximum of a 90 degree angle of attack. It is based on the use of self-scanning photodiode arrays and illuminating laser light beams, together with purpose built processing electronics. The principles behind the design of the system are discussed, together with the results of testing one channel of the system which was used to control the axial position of a magnetically suspended model in SUMSBS. The removal of optically coupled heave position information from the axial position sensing channel is described.

  15. 76 FR 41855 - Columbus Geographic Systems (GIS) Ltd.; Order of Suspension of Trading

    Science.gov (United States)

    2011-07-15

    ... SECURITIES AND EXCHANGE COMMISSION [File No. 500-1] Columbus Geographic Systems (GIS) Ltd.; Order of Suspension of Trading July 13, 2011. It appears to the Securities and Exchange Commission that... Systems (GIS) Ltd. because it has not filed any periodic reports since the period ended June 30, 2008. The...

  16. Heavy vehicle pitch dynamics and suspension tuning

    OpenAIRE

    Cao, Dongpu; Rakheja, Subhash; Su, Chun-Yi

    2008-01-01

    The influence of suspension tuning of passenger cars on bounce and pitch ride performance has been explored in a number of studies, while only minimal efforts have been made for establishing similar rules for heavy vehicles. This study aims to explore pitch dynamics and suspension tunings of a two-axle heavy vehicle with unconnected suspension, which could also provide valuable information for heavy vehicles with coupled suspensions. Based on a generalised pitch-plane model of a two-axle heav...

  17. Magnetic Suspension Technology Workshop

    International Nuclear Information System (INIS)

    Keckler, C.R.; Groom, N.J.; Britcher, C.P.

    1993-01-01

    In order to identify the state of magnetic suspension technology in such areas as rotating systems, pointing of experiments or subsystems, payload isolation, and superconducting materials, a workshop on Magnetic Suspension Technology was held at the Langley Research Center in Hampton, Virginia, on 2-4 Feb. 1988. The workshop included five technical sessions in which a total of 24 papers were presented. The technical sessions covered the areas of pointing, isolation, and measurement, rotating systems, modeling and control, and superconductors. A list of attendees is provided. Separate abstracts have been prepared for articles from this report

  18. Three-axial evaluation of whole-body vibration in agricultural telehandlers: The effects of an active cab-suspension system.

    Science.gov (United States)

    Caffaro, Federica; Preti, Christian; Micheletti Cremasco, Margherita; Cavallo, Eugenio

    2017-10-01

    Agricultural and earth-moving machinery operators are particularly exposed to whole-body vibration (WBV), which has severe effects on health and affects comfort and performance. Few studies have investigated vibrational safety and comfort issues in telescopic handlers. These vehicles are widespread in many off-road applications-such as construction, agriculture, and mining-used to handle loads and to lift persons and equipment. This study investigated the effects of an active hydro-pneumatic cab-suspension system fitted to a telehandler on a driver's vibration exposure along the x-, y-, and z-axes, through both objective and subjective assessments. Sixteen healthy professional telehandler drivers took part in the study. Objective measurements were acquired at the operator's seat, and subjective ratings were taken while participants drove the telehandler with either a deactivated or activated suspension system at 12 kph on an ISO 5008 smooth track. The results showed that the activation of the cab-suspension system reduced the root-mean-square acceleration along the x- and z-axes (p =.038 and p =.000, respectively). Moreover, the frequency analysis showed a reduction in the acceleration along the z-axis in the range of 2-25 Hz (p suspension systems are discussed.

  19. Molecular identification of common Salmonella serovars using multiplex DNA sensor-based suspension array.

    Science.gov (United States)

    Aydin, Muhsin; Carter-Conger, Jacqueline; Gao, Ning; Gilmore, David F; Ricke, Steven C; Ahn, Soohyoun

    2018-04-01

    Salmonella is one of major foodborne pathogens and the leading cause of foodborne illness-related hospitalizations and deaths. It is critical to develop a sensitive and rapid detection assay that can identify Salmonella to ensure food safety. In this study, a DNA sensor-based suspension array system of high multiplexing ability was developed to identify eight Salmonella serovars commonly associated with foodborne outbreaks to the serotype level. Each DNA sensor was prepared by activating pre-encoded microspheres with oligonucleotide probes that are targeting virulence genes and serovar-specific regions. The mixture of 12 different types of DNA sensors were loaded into a 96-well microplate and used as a 12-plex DNA sensor array platform. DNA isolated from Salmonella was amplified by multiplex polymerase chain reaction (mPCR), and the presence of Salmonella was determined by reading fluorescent signals from hybridization between probes on DNA sensors and fluorescently labeled target DNA using the Bio-Plex® system. The developed multiplex array was able to detect synthetic DNA at the concentration as low as 100 fM and various Salmonella serovars as low as 100 CFU/mL within 1 h post-PCR. Sensitivity of this assay was further improved to 1 CFU/mL with 6-h enrichment. The array system also correctly and specifically identified serotype of tested Salmonella strains without any cross-reactivity with other common foodborne pathogens. Our results indicate the developed DNA sensor suspension array can be a rapid and reliable high-throughput method for simultaneous detection and molecular identification of common Salmonella serotypes.

  20. Integration of uniform design and quantum-behaved particle swarm optimization to the robust design for a railway vehicle suspension system under different wheel conicities and wheel rolling radii

    Science.gov (United States)

    Cheng, Yung-Chang; Lee, Cheng-Kang

    2017-10-01

    This paper proposes a systematic method, integrating the uniform design (UD) of experiments and quantum-behaved particle swarm optimization (QPSO), to solve the problem of a robust design for a railway vehicle suspension system. Based on the new nonlinear creep model derived from combining Hertz contact theory, Kalker's linear theory and a heuristic nonlinear creep model, the modeling and dynamic analysis of a 24 degree-of-freedom railway vehicle system were investigated. The Lyapunov indirect method was used to examine the effects of suspension parameters, wheel conicities and wheel rolling radii on critical hunting speeds. Generally, the critical hunting speeds of a vehicle system resulting from worn wheels with different wheel rolling radii are lower than those of a vehicle system having original wheels without different wheel rolling radii. Because of worn wheels, the critical hunting speed of a running railway vehicle substantially declines over the long term. For safety reasons, it is necessary to design the suspension system parameters to increase the robustness of the system and decrease the sensitive of wheel noises. By applying UD and QPSO, the nominal-the-best signal-to-noise ratio of the system was increased from -48.17 to -34.05 dB. The rate of improvement was 29.31%. This study has demonstrated that the integration of UD and QPSO can successfully reveal the optimal solution of suspension parameters for solving the robust design problem of a railway vehicle suspension system.

  1. Hysteresis-induced bifurcation and chaos in a magneto-rheological suspension system under external excitation

    International Nuclear Information System (INIS)

    Zhang Hailong; Zhang Ning; Wang Enrong; Min Fuhong

    2016-01-01

    The magneto-rheological damper (MRD) is a promising device used in vehicle semi-active suspension systems, for its continuous adjustable damping output. However, the innate nonlinear hysteresis characteristic of MRD may cause the nonlinear behaviors. In this work, a two-degree-of-freedom (2-DOF) MR suspension system was established first, by employing the modified Bouc–Wen force–velocity (F–v) hysteretic model. The nonlinear dynamic response of the system was investigated under the external excitation of single-frequency harmonic and bandwidth-limited stochastic road surface. The largest Lyapunov exponent (LLE) was used to detect the chaotic area of the frequency and amplitude of harmonic excitation, and the bifurcation diagrams, time histories, phase portraits, and power spectrum density (PSD) diagrams were used to reveal the dynamic evolution process in detail. Moreover, the LLE and Kolmogorov entropy (K entropy) were used to identify whether the system response was random or chaotic under stochastic road surface. The results demonstrated that the complex dynamical behaviors occur under different external excitation conditions. The oscillating mechanism of alternating periodic oscillations, quasi-periodic oscillations, and chaotic oscillations was observed in detail. The chaotic regions revealed that chaotic motions may appear in conditions of mid-low frequency and large amplitude, as well as small amplitude and all frequency. The obtained parameter regions where the chaotic motions may appear are useful for design of structural parameters of the vibration isolation, and the optimization of control strategy for MR suspension system. (paper)

  2. Linear viscoelastic properties of aging suspensions

    NARCIS (Netherlands)

    Purnomo, E.H.; Purnomo, E.H; van den Ende, Henricus T.M.; Mellema, J.; Mugele, Friedrich Gunther

    2006-01-01

    We have examined the linear viscoelastic behavior of poly-N-isopropylacrylamide (PNIPAM) microgel suspensions in order to obtain insight in the aging processes in these densely packed suspensions at various temperatures below the volume transition temperature. The system is found to display a strong

  3. Semi-active control of tracked vehicle suspension incorporating magnetorheological dampers

    Science.gov (United States)

    Ata, W. G.; Salem, A. M.

    2017-05-01

    In past years, the application of magnetorheological (MR) and electrorheological dampers in vehicle suspension has been widely studied, mainly for the purpose of vibration control. This paper presents theoretical study to identify an appropriate semi-active control method for MR-tracked vehicle suspension. Three representative control algorithms are simulated including the skyhook, hybrid and fuzzy-hybrid controllers. A seven degrees-of-freedom tracked vehicle suspension model incorporating MR dampers has been adopted for comparison between the performance of the three controllers. The model differential equations are derived based on Newton's second law of motion and the proposed control methods are developed. The performance of each control method under bump and sinusoidal road profiles for different vehicle speeds is simulated and compared with the performance of the conventional suspension system in time and frequency domains. The results show that the performance of tracked vehicle suspension with MR dampers is substantially improved. Moreover, the fuzzy-hybrid controller offers an excellent integrated performance in reducing the body accelerations as well as wheel bounce responses compared with the classical skyhook and hybrid controllers.

  4. Development of the Nissan hydraulic active suspension. Nissan yuatsu active suspension no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Kawarasaki, y.; Fukunaga, Y.; Hasegawa, S.; Okuyama, Y.; Omura, I.; Takahashi, K.; Abe, S.; Tsuruta, E. (Nissan Motor Co. Ltd., Tokyo (Japan))

    1989-12-25

    A hydraulic active suspension system, Nissan original product, was developed and mass produced for the first time in the world. The system incorporates a sufficient power source, a high accuracy sensor and a high response device for continuous and intended vehicle control and at the same time delivers high levels of ride comfort and driving performance. The suspension system has four innovative features: skyhook damping, active roll and pitching control, a frequency-dependent damping mechanism, and active steering characteristics control. Under all road and operating conditions, the system actively suppresses vehicle attitude changes and unnecessary movement, and also gently absorbs inputs from the road. This epoch-making system provides a dramatic improvement in vehicle performance, and has been adopted in the Infiniti Q45 luxury sedan. 2 refs., 20 figs., 4 tabs.

  5. Superconducting Electromagnetic Suspension (EMS) system for Grumman Maglev concept

    Science.gov (United States)

    Kalsi, Swarn S.

    1994-01-01

    The Grumman developed Electromagnetic Suspension (EMS) Maglev system has the following key characteristics: a large operating airgap--40 mm; levitation at all speeds; both high speed and low speed applications; no deleterious effects on SC coils at low vehicle speeds; low magnetic field at the SC coil--less than 0.35 T; no need to use non-magnetic/non-metallic rebar in the guideway structure; low magnetic field in passenger cabin--approximately 1 G; low forces on the SC coil; employs state-of-the-art NbTi wire; no need for an active magnet quench protection system; and lower weight than a magnet system with copper coils. The EMS Maglev described in this paper does not require development of any new technologies. The system could be built with the existing SC magnet technology.

  6. 41 CFR 105-74.670 - Suspension.

    Science.gov (United States)

    2010-07-01

    ... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Suspension. 105-74.670 Section 105-74.670 Public Contracts and Property Management Federal Property Management Regulations System...-GOVERNMENTWIDE REQUIREMENTS FOR DRUG-FREE WORKPLACE (FINANCIAL ASSISTANCE) Definitions § 105-74.670 Suspension...

  7. Tribology of swollen starch granule suspensions from maize and potato.

    Science.gov (United States)

    Zhang, Bin; Selway, Nichola; Shelat, Kinnari J; Dhital, Sushil; Stokes, Jason R; Gidley, Michael J

    2017-01-02

    The tribological properties of suspensions of cooked swollen starch granules are characterised for systems based on maize starch and potato starch. These systems are known as granule 'ghosts' due to the release (and removal) of polymer from their structure during cooking. Maize starch ghosts are less swollen than potato starch ghosts, resulting in a higher packing concentration and greater mechanical stability. In a soft-tribological contact, maize ghost suspensions reduce friction compared to the solvent (water), generate bell-shaped tribological profiles characteristic of particle entrainment and show a marked concentration dependence, whereas potato ghost suspensions exhibit lubrication behaviour similar to water. Microscopy analysis of the samples following tribological testing suggests that this is due to the rapid break-up of potato ghosts under the shear and rolling conditions within the tribological contact. A reduction in the small deformation moduli (associated with a weak gel structure) is also observed when the potato ghost suspensions are subjected to steady shear using parallel plate rheometry; both microscopy and particle size analysis show that this is accompanied by the partial shear-induced breakage of ghost particles. This interplay between particle microstructure and the resultant rheological and lubrication dynamics of starch ghost suspensions contributes to an enhanced mechanistic understanding of textural and other functional properties of cooked starches in food and other applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Direct-drive electromagnetic active suspension system with integrated eddy current damping for automotive applications

    NARCIS (Netherlands)

    Gysen, B.L.J.; Paulides, J.J.H.; Lomonova, E.

    2011-01-01

    A direct-drive electromagnetic active suspension system is considered which consists of a tubular permanent magnet actuator in parallel with a coil spring. This system has the ability of improving the ride comfort while maintaining optimum handling and stability. Since safety is of major concern,

  9. Nonlinear Dynamics Analysis of the Semiactive Suspension System with Magneto-Rheological Damper

    Directory of Open Access Journals (Sweden)

    Hailong Zhang

    2015-01-01

    Full Text Available This paper examines dynamical behavior of a nonlinear oscillator which models a quarter-car forced by the road profile. The magneto-rheological (MR suspension system has been established, by employing the modified Bouc-Wen force-velocity (F-v model of magneto-rheological damper (MRD. The possibility of chaotic motions in MR suspension is discovered by employing the method of nonlinear stability analysis. With the bifurcation diagrams and corresponding Lyapunov exponent (LE spectrum diagrams detected through numerical calculation, we can observe the complex dynamical behaviors and oscillating mechanism of alternating periodic oscillations, quasiperiodic oscillations, and chaotic oscillations with different profiles of road excitation, as well as the dynamical evolutions to chaos through period-doubling bifurcations, saddle-node bifurcations, and reverse period-doubling bifurcations.

  10. Equivalent Air Spring Suspension Model for Quarter-Passive Model of Passenger Vehicles

    OpenAIRE

    Abid, Haider J.; Chen, Jie; Nassar, Ameen A.

    2015-01-01

    This paper investigates the GENSIS air spring suspension system equivalence to a passive suspension system. The SIMULINK simulation together with the OptiY optimization is used to obtain the air spring suspension model equivalent to passive suspension system, where the car body response difference from both systems with the same road profile inputs is used as the objective function for optimization (OptiY program). The parameters of air spring system such as initial pressure, volume of bag, l...

  11. A transgenic plant cell-suspension system for expression of epitopes on chimeric Bamboo mosaic virus particles.

    Science.gov (United States)

    Muthamilselvan, Thangarasu; Lee, Chin-Wei; Cho, Yu-Hsin; Wu, Feng-Chao; Hu, Chung-Chi; Liang, Yu-Chuan; Lin, Na-Sheng; Hsu, Yau-Heiu

    2016-01-01

    We describe a novel strategy to produce vaccine antigens using a plant cell-suspension culture system in lieu of the conventional bacterial or animal cell-culture systems. We generated transgenic cell-suspension cultures from Nicotiana benthamiana leaves carrying wild-type or chimeric Bamboo mosaic virus (BaMV) expression constructs encoding the viral protein 1 (VP1) epitope of foot-and-mouth disease virus (FMDV). Antigens accumulated to high levels in BdT38 and BdT19 transgenic cell lines co-expressing silencing suppressor protein P38 or P19. BaMV chimeric virus particles (CVPs) were subsequently purified from the respective cell lines (1.5 and 2.1 mg CVPs/20 g fresh weight of suspended biomass, respectively), and the resulting CVPs displayed VP1 epitope on the surfaces. Guinea pigs vaccinated with purified CVPs produced humoral antibodies. This study represents an important advance in the large-scale production of immunopeptide vaccines in a cost-effective manner using a plant cell-suspension culture system. © 2015 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

  12. Final Report: Model interacting particle systems for simulation and macroscopic description of particulate suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Peter J. Mucha

    2007-08-30

    Suspensions of solid particles in liquids appear in numerous applications, from environmental settings like river silt, to industrial systems of solids transport and water treatment, and biological flows such as blood flow. Despite their importance, much remains unexplained about these complicated systems. Mucha's research aims to improve understanding of basic properties of suspensions through a program of simulating model interacting particle systems with critical evaluation of proposed continuum equations, in close collaboration with experimentalists. Natural to this approach, the original proposal centered around collaboration with studies already conducted in various experimental groups. However, as was detailed in the 2004 progress report, following the first year of this award, a number of the questions from the original proposal were necessarily redirected towards other specific goals because of changes in the research programs of the proposed experimental collaborators. Nevertheless, the modified project goals and the results that followed from those goals maintain close alignment with the main themes of the original proposal, improving efficient simulation and macroscopic modeling of sedimenting and colloidal suspensions. In particular, the main investigations covered under this award have included: (1) Sedimentation instabilities, including the sedimentation analogue of the Rayleigh-Taylor instability (for heavy, particle-laden fluid over lighter, clear fluid). (2) Ageing dynamics of colloidal suspensions at concentrations above the glass transition, using simplified interactions. (3) Stochastic reconstruction of velocity-field dependence for particle image velocimetry (PIV). (4) Stochastic modeling of the near-wall bias in 'nano-PIV'. (5) Distributed Lagrange multiplier simulation of the 'internal splash' of a particle falling through a stable stratified interface. (6) Fundamental study of velocity fluctuations in sedimentation

  13. Analysis of Structural and Material Aspects of Selected Elements of a Hydropneumatic Suspension System in a Passenger Car

    Directory of Open Access Journals (Sweden)

    Konieczny Ł.

    2016-03-01

    Full Text Available The article addresses results of analyses of design solutions and materials commonly used in gas springs for hydropneumatic suspension systems. The authors have discussed main advantages resulting from application of such a design solution in passenger car suspension systems. Fundamental correlations defining the parameters characterising a gas spring with constant gas mass have been referred to. Also materials used in the manufacture of selected gas spring elements have been described

  14. Robust control of nonlinear MAGLEV suspension system with mismatched uncertainties via DOBC approach.

    Science.gov (United States)

    Yang, Jun; Zolotas, Argyrios; Chen, Wen-Hua; Michail, Konstantinos; Li, Shihua

    2011-07-01

    Robust control of a class of uncertain systems that have disturbances and uncertainties not satisfying "matching" condition is investigated in this paper via a disturbance observer based control (DOBC) approach. In the context of this paper, "matched" disturbances/uncertainties stand for the disturbances/uncertainties entering the system through the same channels as control inputs. By properly designing a disturbance compensation gain, a novel composite controller is proposed to counteract the "mismatched" lumped disturbances from the output channels. The proposed method significantly extends the applicability of the DOBC methods. Rigorous stability analysis of the closed-loop system with the proposed method is established under mild assumptions. The proposed method is applied to a nonlinear MAGnetic LEViation (MAGLEV) suspension system. Simulation shows that compared to the widely used integral control method, the proposed method provides significantly improved disturbance rejection and robustness against load variation. Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.

  15. Influence of kinetics on the determination of the surface reactivity of oxide suspensions by acid-base titration.

    Science.gov (United States)

    Duc, M; Adekola, F; Lefèvre, G; Fédoroff, M

    2006-11-01

    The effect of acid-base titration protocol and speed on pH measurement and surface charge calculation was studied on suspensions of gamma-alumina, hematite, goethite, and silica, whose size and porosity have been well characterized. The titration protocol has an important effect on surface charge calculation as well as on acid-base constants obtained by fitting of the titration curves. Variations of pH versus time after addition of acid or base to the suspension were interpreted as diffusion processes. Resulting apparent diffusion coefficients depend on the nature of the oxide and on its porosity.

  16. Application of the aqueous coating suspension for the protection of Gas Turbine Engine parts from corrosion

    Directory of Open Access Journals (Sweden)

    E. G. Ivanov

    2015-01-01

    Full Text Available The article considers the physical nature of receiving diffusion coatings from aqueous suspensions of various alloys for various conditions and their further exploitation. Structure of coatings, advantages and features of the production of coatings from aqueous suspensions are shown. Based on the analysis of thermodynamic reactions in the systems of elements formulations of aqueous suspensions were developed and practical recommendations for their application to the parts of gas turbine engine were given.

  17. Update on quadruple suspension design for Advanced LIGO

    International Nuclear Information System (INIS)

    Aston, S M; Carbone, L; Cutler, R M; Hoyland, D; Barton, M A; Bland, B; Bell, A S; Beveridge, N; Cagnoli, G; Cantley, C A; Cumming, A V; Cunningham, L; Hammond, G D; Haughian, K; Hough, J; Brummitt, A J; Greenhalgh, R J S; Hayler, T M; Heptonstall, A; Heefner, J

    2012-01-01

    We describe the design of the suspension systems for the major optics for Advanced LIGO, the upgrade to LIGO—the Laser Interferometric Gravitational-Wave Observatory. The design is based on that used in GEO600—the German/UK interferometric gravitational wave detector, with further development to meet the more stringent noise requirements for Advanced LIGO. The test mass suspensions consist of a four-stage or quadruple pendulum for enhanced seismic isolation. To minimize suspension thermal noise, the final stage consists of a silica mirror, 40 kg in mass, suspended from another silica mass by four silica fibres welded to silica ears attached to the sides of the masses using hydroxide-catalysis bonding. The design is chosen to achieve a displacement noise level for each of the seismic and thermal noise contributions of 10 −19 m/√Hz at 10 Hz, for each test mass. We discuss features of the design which has been developed as a result of experience with prototypes and associated investigations. (paper)

  18. Simulation of disturbance rejection control of half-car active suspension system using active disturbance rejection control with decoupling transformation

    Science.gov (United States)

    Hasbullah, Faried; Faris, Waleed F.

    2017-12-01

    In recent years, Active Disturbance Rejection Control (ADRC) has become a popular control alternative due to its easy applicability and robustness to varying processes. In this article, ADRC with input decoupling transformation (ADRC-IDT) is proposed to improve ride comfort of a vehicle with an active suspension system using half-car model. The ride performance of the ADRC-IDT is evaluated and compared with decentralized ADRC control as well as the passive system. Simulation results show that both ADRC and ADRC-IDT manage to appreciably reduce body accelerations and able to cope well with varying conditions typically encountered in an active suspension system. Also, it is sufficient to control only the body motions with both active controllers to improve ride comfort while maintaining good road holding and small suspension working space.

  19. Suspension tests on a larger scale. Report from the status seminar on magnetic suspension techniques. Testing of the electrodynamic system started

    Energy Technology Data Exchange (ETDEWEB)

    Rogg, D; Muckli, W

    1976-07-01

    A world record speed for electromagnetically suspended vehicles as well as successful suspension tests with forced-circulation cooled superconducting magnets were the outstanding success reports at the fifth status seminar 'Magnetic suspension techniques' on 31st March and 1st April in Bad Kissingen. The research work on magnetic suspension techniques in the railborne long-distance travel is supported by the Federal Ministry of Research and Technology (BMFT) within the frameworke of the programme 'Railway engineering - New technologies'.

  20. Magnetic suspension and guidance of high speed vehicles. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Alston, I A; Clark, J M; Hayden, J T

    1972-12-01

    Technical and economical assessments of magnetic suspensions for high speed vehicles and transport systems are reported. In these suspensions the suspending magnet takes the form of a powerful superconducting electromagnet that induces currents while it moves over conducting sheets or loops. A number of vehicle track designs are evaluated for operating cost effectiveness. It is shown that propulsion systems using power collected from the track are more expensive than those using power generated onboard the vehicle, and that the conducting sheet suspension is slightly more expensive than the null flux suspension.

  1. Industrial application of ultrasound based in-line rheometry: Visualization of steady shear pipe flow of chocolate suspension in pre-crystallization process

    Science.gov (United States)

    Ouriev, Boris; Windhab, Erich; Braun, Peter; Zeng, Yuantong; Birkhofer, Beat

    2003-12-01

    In the present work an in-line ultrasonic method for investigation of the rheological flow behavior of concentrated suspensions was created. It is based on a nondestructive rheological measuring technique for pilot plant and industrial scale applications. Elsewhere the author discusses a tremendous need for in-line rheological characterization of highly concentrated suspensions exposed to pressure driven shear flow conditions. Most existing on-line methods are based on destructive macro actuators, which are not suitable for materials with sensitive to applied deformation structure. Since the process of our basic interest influences the structure of suspension it would be difficult to separate the effects of rheometric measurement and weakly pronounced structural changes arising from a fine adjustment of the process parameters. The magnitude of these effects is usually associated with the complex flow dynamics of structured liquids and is sensitive to density or temperature fluctuations around the moving rheometric actuator. Interpretation of the results of such measurements can be hindered by process parameter influences on liquid product structure. Therefore, the author introduces an in-line noninvasive rheometric method, which is implemented in a pre-crystallization process of chocolate suspension. Use of ultrasound velocity profile pressure difference (UVP-PD) technique enabled process monitoring of the chocolate pre-crystallization process. Influence of seeded crystals on Rheology of chocolate suspension was recorded and monitored on line. It was shown that even slight velocity pulsations in chocolate mainstream can strongly influence rheological properties besides influencing flow velocity profiles. Based on calculations of power law fit in raw velocity profiles and calculation of wall shear stress from pressure difference measurement, a viscosity function was calculated and monitored on line. On-line results were found to be in a good agreement with off

  2. Mirror suspension system for the TAMA SAS

    International Nuclear Information System (INIS)

    Takamori, Akiteru; Ando, Masaki; Bertolini, Alessandro; Cella, Giancarlo; DeSalvo, Riccardo; Fukushima, Mitsuhiro; Iida, Yukiyoshi; Jacquier, Florian; Kawamura, Seiji; Marka, Szabolcs; Nishi, Yuhiko; Numata, Kenji; Sannibale, Virginio; Somiya, Kentaro; Takahashi, Ryutaro; Tariq, Hareem; Tsubono, Kimio; Ugas, Jose; Viboud, Nicolas; Yamamoto, Hiroaki; Yoda, Tatsuo; Wang Chenyang

    2002-01-01

    Several R and D programmes are ongoing to develop the next generation of interferometric gravitational wave detectors providing the superior sensitivity desired for refined astronomical observations. In order to obtain a wide observation band at low frequencies, the optics need to be isolated from the seismic noise. The TAMA SAS (seismic attenuation system) has been developed within an international collaboration between TAMA, LIGO, and some European institutes, with the main objective of achieving sufficient low-frequency seismic attenuation (-180 dB at 10 HZ). The system suppresses seismic noise well below the other noise levels starting at very low frequencies above 10 Hz. It also includes an active inertial damping system to decrease the residual motion of the optics enough to allow a stable operation of the interferometer. The TAMA SAS also comprises a sophisticated mirror suspension subsystem (SUS). The SUS provides support for the optics and vibration isolation complementing the SAS performance. The SUS is equipped with a totally passive magnetic damper to suppress internal resonances without degrading the thermal noise performance. In this paper we discuss the SUS details and present prototype results

  3. Design of a New Integrated Structure of the Active Suspension System and Emergency Lane Change Test

    Science.gov (United States)

    Zhao, Jing-bo; Liu, Hai-mei; Zhang, Lan-chun; Bei, Shao-yi

    2017-09-01

    An integrated structure of the active suspension system was proposed in order to solve the problem of the individual control of the height of the body or the adjustable damping of the active suspension system of the electric vehicle, which improve the vibration reduction performance of the vehicle. The air bag was used to replace the traditional spiral spring, and the traditional shock absorber was replaced by the damping adjustable shock absorber, and the control module received the body acceleration sensor and the horizontal height sensor signal. The system controlled adjustable damping coefficient of shock absorber through the height of the car body the output of the air pump relay and the height control valve and the output of the electromagnetic valve of the adjustable damping shock absorber, and the emergency lane change test was carried out under different modes of speed of 60km/h. The experimental results indicated that the damping value was greater, average roll angle, yaw angle and average vehicle lateral acceleration were small when vehicle body was in the state of emergency lane change, which verified the feasibility of the integrated control strategy and structure design of the active suspension system. The research has important theoretical research value and engineering application prospect for designing and controlling strategy of vehicle chassis integrated control system.

  4. Clay-cement suspensions - rheological and functional properties

    Science.gov (United States)

    Wojcik, L.; Izak, P.; Mastalska-Poplawska, J.; Gajek, M.

    2017-01-01

    The piping erosion in soil is highly unexpected in civil engineering. Elimination of such damages is difficult, expensive and time-consuming. One of the possibility is the grouting method. This method is still developed into direction of process automation as well as other useful properties of suspensions. Main way of modernization of the grouting method is connected it with rheology of injection and eventuality of fitting them to specific problems conditions. Very popular and useful became binders based on modified clays (clay-cement suspensions). Important principle of efficiency of the grouting method is using of time-dependent pseudothixotropic properties of the clay-cement suspensions. The pseudo-rheounstability aspect of the suspensions properties should be dedicated and fitted to dynamic changes of soil conditions destructions. Whole process of the modification of the suspension rheology is stimulated by the specific agents. This article contains a description of practical aspects of the rheological parameters managing of the clay-cement suspensions, dedicated to the building damages, hydrotechnic constructions etc.

  5. On the Benefits of Semi-Active Suspensions with Inerters

    Directory of Open Access Journals (Sweden)

    Xin-Jie Zhang

    2012-01-01

    Full Text Available Inerters have become a hot topic in recent years especially in vehicle, train, building suspension systems, etc. Eight different layouts of suspensions were analyzed with a quarter-car model in this paper. Dimensionless root mean square (RMS responses of the sprung mass vertical acceleration, the suspension travel, and the tire deflection are derived which were used to evaluate the performance of the quarter-car model. The behaviour of semi-active suspensions with inerters using Groundhook, Skyhook, and Hybrid control has been evaluated and compared to the performance of passive suspensions with inerters. Sensitivity analysis was applied to the development of a high performance semi-active suspension with an inerter. Numerical simulations indicate that a semi-active suspension with an inerter has much better performance than the passive suspension with an inerter, especially with the Hybrid control method, which has the best compromise between comfort and road holding quality.

  6. Torsional asymmetry in suspension bridge systems

    Czech Academy of Sciences Publication Activity Database

    Malík, Josef

    2015-01-01

    Roč. 60, č. 6 (2015), s. 677-701 ISSN 0862-7940 R&D Projects: GA MŠk ED2.1.00/03.0082 Institutional support: RVO:68145535 Keywords : suspension bridge * Hamilton principle * vertical and torsional oscillation * uniqueness * existence Subject RIV: BA - General Mathematics Impact factor: 0.507, year: 2015 http://link.springer.com/article/10.1007%2Fs10492-015-0117-3

  7. PZT crack detection in suspension-based dual stage actuator [for HDDs

    CERN Document Server

    Yung Ping Yeh; Ku, C

    2000-01-01

    An impedance method is proposed to detect cracks of PZT bars in suspension based dual stage-actuators. The frequency response amplitude of impedance at the resonance of 1.95 MHz, the PZT bar width extension mode, was very sensitive to the cracks in PZT material. As cracks in the PZT bars propagated from invisible micro cracks to visible macro cracks, the impedance gain at 1.95 MHz dropped suddenly. (3 refs).

  8. Comparative analysis of the operation efficiency of the continuous and relay control systems of a multi-axle wheeled vehicle suspension

    Science.gov (United States)

    Zhileykin, M. M.; Kotiev, G. O.; Nagatsev, M. V.

    2018-02-01

    In order to improve the efficiency of the multi-axle wheeled vehicles (MWV) automotive engineers are increasing their cruising speed. One of the promising ways to improve ride comfort of the MWV is the development of the dynamic active suspension systems and control laws for such systems. Here, by the dynamic control systems we mean the systems operating in real time mode and using current (instantaneous) values of the state variables. The aim of the work is to develop the MWV suspension optimal control laws that would reduce vibrations on the driver’s seat at kinematic excitation. The authors have developed the optimal control laws for damping the oscillations of the MWV body. The developed laws allow reduction of the vibrations on the driver’s seat and increase in the maximum speed of the vehicle. The laws are characterized in that they allow generating the control inputs in real time mode. The authors have demonstrated the efficiency of the proposed control laws by means of mathematical simulation of the MWV driving over unpaved road with kinematic excitation. The proposed optimal control laws can be used in the MWV suspension control systems with magnetorheological shock absorbers or controlled hydropneumatic springs. Further evolution of the research line can be the development of the energy-efficient MWV suspension control systems with continuous control input on the vehicle body.

  9. Hysteresis-induced bifurcation and chaos in a magneto-rheological suspension system under external excitation

    Science.gov (United States)

    Hailong, Zhang; Enrong, Wang; Fuhong, Min; Ning, Zhang

    2016-03-01

    The magneto-rheological damper (MRD) is a promising device used in vehicle semi-active suspension systems, for its continuous adjustable damping output. However, the innate nonlinear hysteresis characteristic of MRD may cause the nonlinear behaviors. In this work, a two-degree-of-freedom (2-DOF) MR suspension system was established first, by employing the modified Bouc-Wen force-velocity (F-v) hysteretic model. The nonlinear dynamic response of the system was investigated under the external excitation of single-frequency harmonic and bandwidth-limited stochastic road surface. The largest Lyapunov exponent (LLE) was used to detect the chaotic area of the frequency and amplitude of harmonic excitation, and the bifurcation diagrams, time histories, phase portraits, and power spectrum density (PSD) diagrams were used to reveal the dynamic evolution process in detail. Moreover, the LLE and Kolmogorov entropy (K entropy) were used to identify whether the system response was random or chaotic under stochastic road surface. The results demonstrated that the complex dynamical behaviors occur under different external excitation conditions. The oscillating mechanism of alternating periodic oscillations, quasi-periodic oscillations, and chaotic oscillations was observed in detail. The chaotic regions revealed that chaotic motions may appear in conditions of mid-low frequency and large amplitude, as well as small amplitude and all frequency. The obtained parameter regions where the chaotic motions may appear are useful for design of structural parameters of the vibration isolation, and the optimization of control strategy for MR suspension system. Projects supported by the National Natural Science Foundation of China (Grant Nos. 51475246, 51277098, and 51075215), the Research Innovation Program for College Graduates of Jiangsu Province China (Grant No. KYLX15 0725), and the Natural Science Foundation of Jiangsu Province of China (Grant No. BK20131402).

  10. Research on Dynamic Optimization for Road-friendly Vehicle Suspension

    Directory of Open Access Journals (Sweden)

    Lu Yongjie

    2014-10-01

    Full Text Available The heavy vehicle brings large dynamic loads to the road surface, which would reduce vehicle ride comfort and shorten road service life. The structure characteristic of heavy vehicle suspension has a significant impact on vehicle performance. Based on the D'Alembert principle, the dynamics models of independent and integral balanced suspension are proposed considering mass and inertia of balancing rod. The sprung mass acceleration and the tire dynamic force for two kinds of balanced suspension and the traditional quarter vehicle model are compared in frequency-domain and time-domain respectively. It is concluded that a quarter vehicle model simplified for balanced suspension could be used to evaluate the ride comfort of vehicle well, but it has some limitations in assessing the vehicle road-friendliness. Then, the sprung mass acceleration and the road damage coefficients are also analyzed under different vehicle design and running parameters at detail. Some conclusions are obtained: low suspension stiffness, high suspension damping and low tire stiffness are all favorable to improve vehicle performance; there is a saturation range of suspension damping enhancing vehicle performance; improving the road surface roughness and avoiding the no-load running are two effective methods to accomplish the better ride comfort and road-friendliness. The suspension stiffness and damping parameters are chosen for optimal parameters matching of road friendliness based on the approximation optimization method.

  11. Evaluation of commercially available seat suspensions to reduce whole body vibration exposures in mining heavy equipment vehicle operators.

    Science.gov (United States)

    Kim, Jeong Ho; Marin, Luz S; Dennerlein, Jack T

    2018-09-01

    As mining vehicle operators are exposed to high level of Whole body vibration (WBV) for prolonged periods of time, approaches to reduce this exposure are needed for the specific types of exposures in mining. Although various engineering controls (i.e. seat suspension systems) have been developed to address WBV, there has been lack of research to systematically evaluate these systems in reducing WBV exposures in mining heavy equipment vehicle settings. Therefore, this laboratory-based study evaluated the efficacy of different combinations of fore-aft (x-axis), lateral (y-axis), and vertical (z-axis) suspensions in reducing WBV exposures. The results showed that the active vertical suspension more effectively reduced the vertical vibration (∼50%; p's suspension (10%; p's suspension systems did not attenuate the corresponding axis vibration (p's > 0.06) and sometimes amplified the floor vibration, especially when the non-vertical vibration was predominant (p's suspensions to address non-vertical WBV exposures, especially because these non-vertical WBV exposures can increase risks for adverse health effects including musculoskeletal loading, discomfort, and impaired visual acuity. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. Hybrid superconducting magnetic suspensions

    International Nuclear Information System (INIS)

    Tixador, P.; Hiebel, P.; Brunet, Y.; Chaud, X.; Gautier-Picard, P.

    1996-01-01

    Superconductors, especially high T c ones, are the most attractive materials to design stable and fully passive magnetic suspensions which have to control five degrees of freedom. The hybrid superconducting magnetic suspensions present high performances and a simple cooling mode. They consist of a permanent magnet bearing, stabilized by a suitable magnet-superconductor structure. Several designs are given and compared in terms of forces and stiffnesses. The design of the magnet bearing plays an important part. The superconducting magnetic bearing participates less in levitation but must provide a high stabilizing stiffness. This is achieved by the magnet configuration, a good material in term of critical current density and field cooling. A hybrid superconducting suspension for a flywheel is presented. This system consists of a magnet thrust bearing stabilized by superconductors interacting with an alternating polarity magnet structure. First tests and results are reported. Superconducting materials are magnetically melt-textured YBaCuO

  13. Demands, Potentials, and Economic Aspects of Thermal Spraying with Suspensions: A Critical Review

    Science.gov (United States)

    Toma, Filofteia-Laura; Potthoff, Annegret; Berger, Lutz-Michael; Leyens, Christoph

    2015-10-01

    Research and development work for about one decade have demonstrated many unique thermal spray coating properties, particularly for oxide ceramic coatings by using suspensions of fine powders as feedstock in APS and HVOF processes. Some particular advantages are direct feeding of fine nano- and submicron-scale particles avoiding special feedstock powder preparation, ability to produce coating thicknesses ranging from 10 to 50 µm, homogeneous microstructure with less anisotropy and lower surface roughness compared to conventional coatings, possibility of retention of the initial crystalline phases, and others. This paper discusses the main aspects of thermal spraying with suspensions which have been taken into account in order to produce these coatings on an economical way. The economic efficiency of the process depends on the availability of suitable additional system components (suspension feeder, injectors), on the development and handling of stable suspensions, as well as on the high process stability for acceptance at industrial scale. Special focus is made on the development and processability of highly concentrated water-based suspensions. While costs and operational safety clearly speak for use of water as a liquid media for preparing suspensions on an industrial scale, its use is often critically discussed due to the required higher heat input during spraying compared to alcoholic suspensions.

  14. Suspension-thermal noise in spring–antispring systems for future gravitational-wave detectors

    Science.gov (United States)

    Harms, Jan; Mow-Lowry, Conor M.

    2018-01-01

    Spring–antispring systems have been investigated in the context of low-frequency seismic isolation in high-precision optical experiments. These systems provide the possibility to tune the fundamental resonance frequency to, in principle, arbitrarily low values, and at the same time maintain a compact design. It was argued though that thermal noise in spring–antispring systems would not be as small as one may naively expect from lowering the fundamental resonance frequency. In this paper, we present calculations of suspension-thermal noise for spring–antispring systems potentially relevant in future gravitational-wave detectors, i.e. the beam-balance tiltmeter, and the Roberts linkage. We find a concise expression of the suspension-thermal noise spectrum, which assumes a form very similar to the well-known expression for a simple pendulum. For systems such as the Roberts linkage foreseen as passive seismic isolation, we find that while they can provide strong seismic isolation due to a very low fundamental resonance frequency, their thermal noise is determined by the dimension of the system and is insensitive to fine-tunings of the geometry that can strongly influence the resonance frequency. By analogy, i.e. formal similarity of the equations of motion, this is true for all horizontal mechanical isolation systems with spring–antispring dynamics. This imposes strict requirements on mechanical spring–antispring systems for seismic isolation in potential future low-frequency gravitational-wave detectors as we discuss for the four main concepts, atom-interferometric, superconducting, torsion-bars, and conventional laser interferometer, and generally suggests that thermal noise needs to be evaluated carefully for high-precision experiments implementing spring–antispring dynamics.

  15. Model-assisted measurements of suspension-feeding flow velocities.

    Science.gov (United States)

    Du Clos, Kevin T; Jones, Ian T; Carrier, Tyler J; Brady, Damian C; Jumars, Peter A

    2017-06-01

    Benthic marine suspension feeders provide an important link between benthic and pelagic ecosystems. The strength of this link is determined by suspension-feeding rates. Many studies have measured suspension-feeding rates using indirect clearance-rate methods, which are based on the depletion of suspended particles. Direct methods that measure the flow of water itself are less common, but they can be more broadly applied because, unlike indirect methods, direct methods are not affected by properties of the cleared particles. We present pumping rates for three species of suspension feeders, the clams Mya arenaria and Mercenaria mercenaria and the tunicate Ciona intestinalis , measured using a direct method based on particle image velocimetry (PIV). Past uses of PIV in suspension-feeding studies have been limited by strong laser reflections that interfere with velocity measurements proximate to the siphon. We used a new approach based on fitting PIV-based velocity profile measurements to theoretical profiles from computational fluid dynamic (CFD) models, which allowed us to calculate inhalant siphon Reynolds numbers ( Re ). We used these inhalant Re and measurements of siphon diameters to calculate exhalant Re , pumping rates, and mean inlet and outlet velocities. For the three species studied, inhalant Re ranged from 8 to 520, and exhalant Re ranged from 15 to 1073. Volumetric pumping rates ranged from 1.7 to 7.4 l h -1 for M . arenaria , 0.3 to 3.6 l h -1 for M . m ercenaria and 0.07 to 0.97 l h -1 for C . intestinalis We also used CFD models based on measured pumping rates to calculate capture regions, which reveal the spatial extent of pumped water. Combining PIV data with CFD models may be a valuable approach for future suspension-feeding studies. © 2017. Published by The Company of Biologists Ltd.

  16. 3D modeling design and engineering analysis of automotive suspension beam

    Directory of Open Access Journals (Sweden)

    Ju Zhi Lan

    2016-01-01

    Full Text Available Automotive suspension is an important device for transmission and torque. The main parameters and dimensions of 40 tons of heavy duty truck spring suspension system are designed in the paper. According to the data, the 3D modeling and virtual assembly of the leaf spring suspension are carried out by using parametric design. Structural stress of spring suspension is analyzed which can provide a guide and basis for the design of the leaf spring suspension.

  17. Evaluation of indeterminacy of initial data for cad system of electric engine suspension

    Science.gov (United States)

    Antipin, D. Ya; Izmerov, O. V.; Shorokhov, S. G.; Nadtochey, D. G.

    2018-03-01

    The research of the variants of the suspension of the traction electric motor of diesel locomotives was performed. It was found that the method of designing the suspension does not take into consideration the possible changes of the characteristics of the parts in operation conditions. Variants of the suspension design were proposed and patented, which provide the work reliability despite the operating conditions.

  18. DESIGN AN INTELLIGENT CONTROLLER FOR FULL VEHICLE NONLINEAR ACTIVE SUSPENSION SYSTEMS

    OpenAIRE

    Aldair, A. A.; Wang, W. J.

    2011-01-01

    The main objective of designed the controller for a vehicle suspension system is to reduce the discomfort sensed by passengers which arises from road roughness and to increase the ride handling associated with the pitching and rolling movements. This necessitates a very fast and accurate controller to meet as much control objectives, as possible. Therefore, this paper deals with an artificial intelligence Neuro-Fuzzy (NF) technique to design a robust controller to meet the control objectives....

  19. Development of a falling ball rheometer with applications to opaque systems: measurements of the rheology of suspensions of rods

    International Nuclear Information System (INIS)

    Powell, R.L.; Mondy, L.A.; Stoker, G.G.; Milliken, W.J.; Graham, A.L.

    1989-01-01

    With falling ball rheometry, we have measured the apparent relative viscosity of suspensions of large, neutrally buoyant, rigid rods in a viscous Newtonian fluid, while approximately maintaining the rods in a randomly oriented configuration. A new technique for measuring the time of flight of a ball between two positions is used. This computerized technique, based upon an eddy current detector, enables us to determine the position of a metallic (nonmagnetic) ball falling through an opaque suspension, with high accuracy (less than 1.5% error). The rods for the suspensions had a nominal aspect ratio of 10 and experiments were carried out at a single volume fraction, 0.05. Two populations of rods were used to having nominal diameters of 1.5875 mm and 3.175 mm. To within the errors of these experiments, suspensions from both populations had the same relative viscosity, with the overall average being 1.457. This viscosity was significantly different from that of a similar suspension (volume fraction=0.05) of rods of nominal aspect ratio 20 and it agreed well with theoretical results for the viscosity of a dilute suspension of randomly oriented rods

  20. Superconducting magnet suspensions in high speed ground transport

    Energy Technology Data Exchange (ETDEWEB)

    Alston, I A

    1973-08-01

    A technical and economic definition of high speed ground transport systems using magnetic suspensions is given. The full range of common superconducting suspensions and of propulsions are covered with designs produced for speeds ranging from 100 m/s (225 miles/hr) to 250 m/s (560 mile/hr). Technical descriptions of the vehicles, their suspensions, propulsions and tracks are given in some detail and operating costs are presented for all the systems together with details of the breakdown of costs and the capital costs involved. The design assumptions, the costing procedure and a cost sensitivity study are presented. It is concluded that the systems are technically feasible; that they are suited to existing duorail track for low speed running and that, in these circumstances, they would be economically viable over many routes.

  1. Rheology and microstructure of dilute graphene oxide suspension

    International Nuclear Information System (INIS)

    Tesfai, Waka; Singh, Pawan; Shatilla, Youssef; Iqbal, Muhammad Z.; Abdala, Ahmed A.

    2013-01-01

    Graphene and graphene oxide are potential candidates as nanofluids for thermal management applications. Here, we investigate the rheological properties and intrinsic viscosity of aqueous suspension of graphene and use the measured intrinsic viscosity to determine the aspect ratio of graphene oxide. Dilute suspension of graphene oxide (0.05 to 0.5 mg/mL) exhibits a shear thinning behavior at low shear rates followed by a shear-independent region that starts at shear rate between 5 and 100/s depending on the concentration. This shear thinning behavior becomes more pronounced with the increase of particle loading. Moreover, AFM imaging of the dried graphene oxide indicates the evolution of irregular and thin low fractal aggregates of 0.3–1.8 nm thickness at lower concentrations to oblate compact structures of 1–18 nm thickness of nanosheets at higher concentration. These observations elucidate the microstructure growth mechanisms of graphene oxide in multiphase systems, which are important for nanofluids applications and for dispersing graphene and graphene oxide in composite materials. The suspension has a very high intrinsic viscosity of 1661 due to the high graphene oxide aspect ratio. Based on this intrinsic viscosity, we predict graphene oxide aspect ratio of 2445. While the classical Einstein and Batchelor models underestimate the relative viscosity of graphene oxide suspension, Krieger–Dougherty prediction is in a good agreement with the experimental measurement

  2. A multiobjective ? control strategy for energy harvesting in regenerative vehicle suspension systems

    Science.gov (United States)

    Casavola, Alessandro; Di Iorio, Fabio; Tedesco, Francesco

    2018-04-01

    A significant amount of energy induced by road unevenness and vehicle roll and pitch motions is usually dissipated by conventional shock-absorbers. In this paper, a novel active multiobjective ? control design methodology is proposed which explicitly includes, besides the usual control objectives on ride comfort, road handling and suspension stroke, the amount of energy to be harvested as an additional, though conflicting, control objective and allows the designer to directly trade-off among them depending on the application. An electromechanical regenerative suspension system is considered where the viscous damper is replaced by a linear electrical motor which is actively governed. It is shown that the proposed control law is able to achieve remarkable improvements on the amount of the harvested energy with respect to passive or semi-active control strategies while maintaining the other objectives at acceptable levels. Simulative studies undertaken via CarSim are also reported that confirm the potentiality and flexibility of the proposed control design strategy.

  3. A high-force controllable MR fluid damper–liquid spring suspension system

    International Nuclear Information System (INIS)

    Raja, Pramod; Wang, Xiaojie; Gordaninejad, Faramarz

    2014-01-01

    The goal of the present research is to investigate the feasibility of incorporating a liquid spring in a semi-active suspension system for use in heavy off-road vehicles. A compact compressible magneto-rheological (MR) fluid damper–liquid spring (CMRFD–LS) with high spring rate is designed, developed and tested. Compressible MR fluids with liquid spring and variable damping characteristics are used. These fluids can offer unique functions in reducing the volume/weight of vehicle struts and improving vehicle dynamic stability and safety. The proposed device consists of a cylinder and piston–rod arrangement with an internal annular MR fluid valve. The internal pressures in the chambers on either side of the piston develop the spring force, while the pressure difference across the MR valve produces the damping force, when the fluid flows through the MR valve. Harmonic characterization of the CMRFD–LS is performed and the force–displacement results are presented. A fluid-mechanics based model is also developed to predict the performance of the system at different operating conditions and compared to the experimental results. Good agreement between the experimental results and theoretical predictions has been achieved. (paper)

  4. Design of LQG Controller for Active Suspension without Considering Road Input Signals

    Directory of Open Access Journals (Sweden)

    Hui Pang

    2017-01-01

    Full Text Available As the road conditions are completely unknown in the design of a suspension controller, an improved linear quadratic and Gaussian distributed (LQG controller is proposed for active suspension system without considering road input signals. The main purpose is to optimize the vehicle body acceleration, pitching angular acceleration, displacement of suspension system, and tire dynamic deflection comprehensively. Meanwhile, it will extend the applicability of the LQG controller. Firstly, the half-vehicle and road input mathematical models of an active suspension system are established, with the weight coefficients of each evaluating indicator optimized by using genetic algorithm (GA. Then, a simulation model is built in Matlab/Simulink environment. Finally, a comparison of simulation is conducted to illustrate that the proposed LQG controller can obtain the better comprehensive performance of vehicle suspension system and improve riding comfort and handling safety compared to the conventional one.

  5. Development and Application of Binary Suspensions in the Ternary System Cr2O3-TiO2-Al2O3 for S-HVOF Spraying

    Science.gov (United States)

    Potthoff, Annegret; Kratzsch, Robert; Barbosa, Maria; Kulissa, Nick; Kunze, Oliver; Toma, Filofteia-Laura

    2018-04-01

    Compositions in the system Cr2O3-TiO2-Al2O3 are among the most used ceramic materials for thermally sprayed coating solutions. Cr2O3 coatings present good sliding wear resistance; Al2O3 coatings show excellent insulation behavior and TiO2 striking corrosion properties. In order to combine these properties, coatings containing more than one oxide are highly interesting. The conventional spraying process is limited to the availability of binary feedstock powders with defined compositions. The use of suspensions offers the opportunity for tailor-made chemical compositions: within the triangle of Cr2O3-TiO2-Al2O3, each mixture of oxides can be created. Criteria for the selection of raw materials as well as the relevant aspects for the development of binary suspensions in the Cr2O3-TiO2-Al2O3 system to be used as feedstock for thermal spraying are presented. This formulation of binary suspensions required the development of water-based single-oxide suspensions with suitable behavior; otherwise, the interaction between the particles while mixing could lead up to a formation of agglomerates, which affect both the stability of the spray process and the coating properties. For the validation of this formulation procedure, binary Cr2O3-TiO2 and Al2O3-TiO2 suspensions were developed and sprayed using the S-HVOF process. The binary coatings were characterized and discussed in terms of microstructure and microhardness.

  6. Development and Application of Binary Suspensions in the Ternary System Cr2O3-TiO2-Al2O3 for S-HVOF Spraying

    Science.gov (United States)

    Potthoff, Annegret; Kratzsch, Robert; Barbosa, Maria; Kulissa, Nick; Kunze, Oliver; Toma, Filofteia-Laura

    2018-03-01

    Compositions in the system Cr2O3-TiO2-Al2O3 are among the most used ceramic materials for thermally sprayed coating solutions. Cr2O3 coatings present good sliding wear resistance; Al2O3 coatings show excellent insulation behavior and TiO2 striking corrosion properties. In order to combine these properties, coatings containing more than one oxide are highly interesting. The conventional spraying process is limited to the availability of binary feedstock powders with defined compositions. The use of suspensions offers the opportunity for tailor-made chemical compositions: within the triangle of Cr2O3-TiO2-Al2O3, each mixture of oxides can be created. Criteria for the selection of raw materials as well as the relevant aspects for the development of binary suspensions in the Cr2O3-TiO2-Al2O3 system to be used as feedstock for thermal spraying are presented. This formulation of binary suspensions required the development of water-based single-oxide suspensions with suitable behavior; otherwise, the interaction between the particles while mixing could lead up to a formation of agglomerates, which affect both the stability of the spray process and the coating properties. For the validation of this formulation procedure, binary Cr2O3-TiO2 and Al2O3-TiO2 suspensions were developed and sprayed using the S-HVOF process. The binary coatings were characterized and discussed in terms of microstructure and microhardness.

  7. Estimation of Road Loads and Vibration Transmissibility of Torsion Bar Suspension System in a Tracked Vehicle

    Science.gov (United States)

    Gagneza, G. P. S.; Chandramohan, Sujatha

    2018-05-01

    Designing the suspension system of a tracked combat vehicle (CV) is really challenging as it has to satisfy conflicting requirements of good ride comfort, vehicle handling and stability characteristics. Many studies in this field have been reported in literature and it has been found that torsion bars satisfy the designer's conflicting requirements of good ride and handling and thus have reserved a place for themselves as the most widely used suspension system for military track vehicles. Therefore, it is imperative to evaluate the effectiveness of the torsion bar under dynamic conditions of undulating terrain and validating the same by correlating it with computer simulation results. Thus in the present work, the dynamic simulation of a 2N + 4 degrees of freedom (DOF) mathematical model has been carried out using MATLAB Simulink and the vibration levels were also measured experimentally on a 12 wheel stationed high mobility military tracked infantry combat vehicle (ICV BMP-II) traversing different terrain, that is, Aberdeen proving ground (APG) and Sinusoidal, at a constant vehicle speed. The dynamic force transmitted to the hull CG through the 12 torsion bar suspension systems was computed to be around 26,700 N and found to match the measured values. The vibration isolation of the torsion bar in bounce was found to be effective, with a transmissibility from the road wheel to the hull of about 0.6.

  8. Global sensitivity analysis of bogie dynamics with respect to suspension components

    Energy Technology Data Exchange (ETDEWEB)

    Mousavi Bideleh, Seyed Milad, E-mail: milad.mousavi@chalmers.se; Berbyuk, Viktor, E-mail: viktor.berbyuk@chalmers.se [Chalmers University of Technology, Department of Applied Mechanics (Sweden)

    2016-06-15

    The effects of bogie primary and secondary suspension stiffness and damping components on the dynamics behavior of a high speed train are scrutinized based on the multiplicative dimensional reduction method (M-DRM). A one-car railway vehicle model is chosen for the analysis at two levels of the bogie suspension system: symmetric and asymmetric configurations. Several operational scenarios including straight and circular curved tracks are considered, and measurement data are used as the track irregularities in different directions. Ride comfort, safety, and wear objective functions are specified to evaluate the vehicle’s dynamics performance on the prescribed operational scenarios. In order to have an appropriate cut center for the sensitivity analysis, the genetic algorithm optimization routine is employed to optimize the primary and secondary suspension components in terms of wear and comfort, respectively. The global sensitivity indices are introduced and the Gaussian quadrature integrals are employed to evaluate the simplified sensitivity indices correlated to the objective functions. In each scenario, the most influential suspension components on bogie dynamics are recognized and a thorough analysis of the results is given. The outcomes of the current research provide informative data that can be beneficial in design and optimization of passive and active suspension components for high speed train bogies.

  9. Global sensitivity analysis of bogie dynamics with respect to suspension components

    International Nuclear Information System (INIS)

    Mousavi Bideleh, Seyed Milad; Berbyuk, Viktor

    2016-01-01

    The effects of bogie primary and secondary suspension stiffness and damping components on the dynamics behavior of a high speed train are scrutinized based on the multiplicative dimensional reduction method (M-DRM). A one-car railway vehicle model is chosen for the analysis at two levels of the bogie suspension system: symmetric and asymmetric configurations. Several operational scenarios including straight and circular curved tracks are considered, and measurement data are used as the track irregularities in different directions. Ride comfort, safety, and wear objective functions are specified to evaluate the vehicle’s dynamics performance on the prescribed operational scenarios. In order to have an appropriate cut center for the sensitivity analysis, the genetic algorithm optimization routine is employed to optimize the primary and secondary suspension components in terms of wear and comfort, respectively. The global sensitivity indices are introduced and the Gaussian quadrature integrals are employed to evaluate the simplified sensitivity indices correlated to the objective functions. In each scenario, the most influential suspension components on bogie dynamics are recognized and a thorough analysis of the results is given. The outcomes of the current research provide informative data that can be beneficial in design and optimization of passive and active suspension components for high speed train bogies.

  10. Microbial spoilage, instability risk of antacid suspension in the presence of commonly used preservative system.

    Science.gov (United States)

    Khan, Jamshaid Ali; Khan, Imran Ullah; Iqbal, Zafar; Nasir, Fazli; Muhammad, Salar; Hannan, Peer Abdul; Ullah, Irfan

    2015-09-01

    Manifestation of microbial spoilage of any product by bacteria and to assess the effectiveness of the anti-microbial preservatives (parabens) used for the prevention and stability purpose. The aim of the present work is to study the effectiveness of preservatives used in the antacid suspensions and to analyze the effect of microbial growth on the quality of respective antacid suspensions. Samples of various antacid suspensions were randomly collected from local market and Government hospital pharmacies. Three different antacid formulations were prepared in the laboratory. All the formulations were preliminarily evaluated on the basis of organoleptic characteristics, pH, viscosity and assay. Efficacy of the preservative system in suspension formulation was determined by inoculating the samples in its final container, with specific strains of bacteria i.e. Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 9027 and Staphylococcus aureus ATCC 6538, taking samples from the inoculated preparation at specified intervals of time i.e. 0 time, 07 days, 14 days and 28 days, growing it on nutrient agar medium and colony forming units (CFUs) were scored by plate count. At the same time the samples were also subjected to qualitative and quantitative testing. The decrease in CFU and alteration in assay, pH and viscosity was observed in all the formulations except formulation M2 and F3 that showed stability throughout the study period.

  11. Structural analysis of compression helical spring used in suspension system

    Science.gov (United States)

    Jain, Akshat; Misra, Sheelam; Jindal, Arun; Lakhian, Prateek

    2017-07-01

    The main aim of this work has to develop a helical spring for shock absorber used in suspension system which is designed to reduce shock impulse and liberate kinetic energy. In a vehicle, it increases comfort by decreasing amplitude of disturbances and it improves ride quality by absorbing and dissipating energy. When a vehicle is in motion on a road and strikes a bump, spring comes into action quickly. After compression, spring will attempt to come to its equilibrium state which is on level road. Helical springs can be made lighter with more strength by reducing number of coils and increasing the area. In this research work, a helical spring is modeled and analyzed to substitute the existing steel spring which is used in suspension. By using different materials, stress and deflection of helical spring can be varied. Comparability between existing spring and newly replaced spring is used to verify the results. For finding detailed stress distribution, finite element analysis is used to find stresses and deflection in both the helical springs. Finite element analysis is a method which is used to find proximate solutions of a physical problem defined in a finite domain. In this research work, modeling of spring is accomplished using Solid Works and analysis on Ansys.

  12. An Improved Genetic Algorithm to Optimize Spatial Locations for Double-Wishbone Type Suspension System with Time Delay

    Directory of Open Access Journals (Sweden)

    Qiang Li

    2018-01-01

    Full Text Available By taking account of double-wishbone independent suspension with two unequal-length arms, the coordinate values of articulated geometry are based on structural limitations and constraint equations of alignment parameters. The sensitivities of front wheel alignment parameters are analyzed using the space analytic geometry method with insight module in ADAMS® software. The multiobjective optimization functions are designed to calculate the coordinate values of hardpoints with front suspension since the effect of time delay due to wheelbase can be easily obtained by vehicle speed. The K&C characteristics have been investigated using GA solutions in the simulation environment. The camber angle decreases from 1.152° to 1.05° and toe-in angle reduces from 1.036° to 0.944°. The simulation results demonstrate that the suggested optimization method is able to satisfy the suspension motion to enhance ride comfort. Experimental results, obtained by K&C test bench, also indicate that the optimized suspension can track the desired trajectory while keeping the vehicle performance in various road conditions.

  13. LMI-Based H¥ Anti-Rollover Control Algorithm of Vehicle Active Suspension

    Directory of Open Access Journals (Sweden)

    LIAO Cong

    2014-10-01

    Full Text Available In order to improve the anti-rollover ability for vehicles, a 4 DOF vehicle rollover dynamics model is established, base on which we have designed an active suspension anti-rollover controller and proposed the H¥ control strategy. Simulations were carried out using Matlab/Simulink, and results show that the proposed control scheme can not only reduce the roll angle and roll angular velocity, but also improve the rollover stability of the vehicle and reduce the probability of vehicle rollover accidents.

  14. Network synthesis and parameter optimization for vehicle suspension with inerter

    Directory of Open Access Journals (Sweden)

    Long Chen

    2016-12-01

    Full Text Available In order to design a comfortable-oriented vehicle suspension structure, the network synthesis method was utilized to transfer the problem into solving a timing robust control problem and determine the structure of “inerter–spring–damper” suspension. Bilinear Matrix Inequality was utilized to obtain the timing transfer function. Then, the transfer function of suspension system can be physically implemented by passive elements such as spring, damper, and inerter. By analyzing the sensitivity and quantum genetic algorithm, the optimized parameters of inerter–spring–damper suspension were determined. A quarter-car model was established. The performance of the inerter–spring–damper suspension was verified under random input. The simulation results manifested that the dynamic performance of the proposed suspension was enhanced in contrast with traditional suspension. The root mean square of vehicle body acceleration decreases by 18.9%. The inerter–spring–damper suspension can inhibit the vertical vibration within the frequency of 1–3 Hz effectively and enhance the performance of ride comfort significantly.

  15. Optical filter based on Fabry-Perot structure using a suspension of goethite nanoparticles as electro-optic material

    Science.gov (United States)

    Abbas, Samir; Dupont, Laurent; Dozov, Ivan; Davidson, Patrick; Chanéac, Corinne

    2018-02-01

    We have investigated the feasibility of optical tunable filters based on a Fabry-Perot etalon that uses a suspension of goethite (α-FeOOH) nanorods as electro-optic material for application in optical telecommunications in the near IR range. These synthetic nanoparticles have a high optical anisotropy that give rise to a very strong Kerr effect in their colloidal suspensions. Currently, these particles are dispersed in aqueous solvent, with pH2 to ensure the colloidal electrostatic stability. However, the high conductivity of these suspensions requires using high-frequency electric fields (f > 1 MHz), which brings about a high power consumption of the driver. To decrease the field frequency, we have changed the solvent to ethylene glycol which has a lower electrical conductivity than the aqueous solvent. We have built a Fabry-Perot cell, filled with this colloidal suspension in the isotropic phase, and showed that a phase shift of 14 nm can be obtained in a field of 3V/μm. Therefore, the device can operate as a tunable filter. A key advantage of this filter is that it is, by principle, completely insensitive to the polarization of the input light. However, several technological issues still need to be solved, such as ionic contamination of the suspension from the blocking layers, and dielectrophoretic and thermal effects.

  16. Rheology of dense suspensions of non colloidal particles

    Science.gov (United States)

    Guazzelli, Élisabeth

    2017-06-01

    Dense suspensions are materials with broad applications both in industrial processes (e.g. waste disposal, concrete, drilling muds, metalworking chip transport, and food processing) and in natural phenomena (e.g. flows of slurries, debris, and lava). Despite its long research history and its practical relevance, the mechanics of dense suspensions remain poorly understood. The major difficulty is that the grains interact both by hydrodynamic interactions through the liquid and by mechanical contact. These systems thus belong to an intermediate regime between pure suspensions and granular flows. We show that we can unify suspension and granular rheology under a common framework by transferring the frictional approach of dry granular media to wet suspensions of spherical particles. We also discuss non-Newtonian behavior such as normal-stress differences and shear-induced migration. Beyond the classical problem of dense suspension of hard spheres which is far from being completely resolved, there are also entirely novel avenues of study concerning more complex mixtures of particles and fluids such as those involving other types of particles (e.g. fibers) or non-Newtonian fluids that we will also address.

  17. Establishment of sorghum cell suspension culture system for ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-03-18

    Mar 18, 2008 ... Additionally, sorghum cell suspension cultures have been initiated from the friable ... proteomics technologies. The field of proteomics is .... air dried at room temperature and resuspended in 2 ml of urea buffer [9 M urea, 2 M ...

  18. Modal Parameter Identification and Numerical Simulation for Self-anchored Suspension Bridges Based on Ambient Vibration

    Science.gov (United States)

    Liu, Bing; Sun, Li Guo

    2018-06-01

    This paper chooses the Nanjing-Hangzhou high speed overbridge, a self-anchored suspension bridge, as the research target, trying to identify the dynamic characteristic parameters of the bridge by using the peak-picking method to analyze the velocity response data under ambient excitation collected by 7 vibration pickup sensors set on the bridge deck. The ABAQUS is used to set up a three-dimensional finite element model for the full bridge and amends the finite element model of the suspension bridge based on the identified modal parameter, and suspender force picked by the PDV100 laser vibrometer. The study shows that the modal parameter can well be identified by analyzing the bridge vibration velocity collected by 7 survey points. The identified modal parameter and measured suspender force can be used as the basis of the amendment of the finite element model of the suspension bridge. The amended model can truthfully reflect the structural physical features and it can also be the benchmark model for the long-term health monitoring and condition assessment of the bridge.

  19. Optimisation of active suspension control inputs for improved performance of active safety systems

    Science.gov (United States)

    Čorić, Mirko; Deur, Joško; Xu, Li; Tseng, H. Eric; Hrovat, Davor

    2018-01-01

    A collocation-type control variable optimisation method is used to investigate the extent to which the fully active suspension (FAS) can be applied to improve the vehicle electronic stability control (ESC) performance and reduce the braking distance. First, the optimisation approach is applied to the scenario of vehicle stabilisation during the sine-with-dwell manoeuvre. The results are used to provide insights into different FAS control mechanisms for vehicle performance improvements related to responsiveness and yaw rate error reduction indices. The FAS control performance is compared to performances of the standard ESC system, optimal active brake system and combined FAS and ESC configuration. Second, the optimisation approach is employed to the task of FAS-based braking distance reduction for straight-line vehicle motion. Here, the scenarios of uniform and longitudinally or laterally non-uniform tyre-road friction coefficient are considered. The influences of limited anti-lock braking system (ABS) actuator bandwidth and limit-cycle ABS behaviour are also analysed. The optimisation results indicate that the FAS can provide competitive stabilisation performance and improved agility when compared to the ESC system, and that it can reduce the braking distance by up to 5% for distinctively non-uniform friction conditions.

  20. Techniques for extreme attitude suspension of a wind tunnel model in a magnetic suspension and balance system. Ph.D. Thesis

    Science.gov (United States)

    Parker, David Huw

    1989-01-01

    Although small scale magnetic suspension and balance systems (MSBSs) for wind tunnel use have been in existence for many years, they have not found general application in the production testing of flight vehicles. One reason for this is thought to lie in the relatively limited range of attitudes over which a wind tunnel model may be suspended. Modifications to a small MSBS to permit the suspension and control of axisymmetric models over angles of attack from less than zero to over ninety degrees are reported. Previous work has shown that existing arrangement of ten electromagnets was unable to generate one of the force components needed for control at extreme attitudes. Examination of possible solutions resulted in a simple alteration to rectify this deficiency. To generate the feedback signals to control the suspended model, an optical position sensing system using collimated laser beams and photodiode arrays was installed and tested. An analytical basis was developed for distributing the demands for force and moment needed for model stabilization amonge the electromagnets over the full attitude range. This was implemented by an MSBS control program able to continually adjust the distribution for the instantaneous incidence in accordance with prescheduled data. Results presented demonstrate rotations of models from zero to ninety degrees at rates up to ninety degrees per second, with pitching rates rising to several hundred degrees per second in response to step-change demands. A study of a design for a large MSBS suggests that such a system could be given the capability to control a model in six degrees of freedom over an unlimited angle of attack range.

  1. Active Electromechanical Suspension System for Planetary Rovers, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Balcones Technologies, LLC proposes to adapt actively controlled suspension technology developed by The University of Texas at Austin Center for Electromechanics...

  2. Neural network compensation of semi-active control for magneto-rheological suspension with time delay uncertainty

    International Nuclear Information System (INIS)

    Dong Xiaomin; Yu Miao; Liao Changrong; Chen Weimin; Li Zushu

    2009-01-01

    This study presents a new intelligent control method, human-simulated intelligent control (HSIC) based on the sensory motor intelligent schema (SMIS), for a magneto-rheological (MR) suspension system considering the time delay uncertainty of MR dampers. After formulating the full car dynamic model featuring four MR dampers, the HSIC based on eight SMIS is derived. A neural network model is proposed to compensate for the uncertain time delay of the MR dampers. The HSIC based on SMIS is then experimentally realized for the manufactured full vehicle MR suspension system on the basis of the dSPACE platform. Its performance is evaluated and compared under various road conditions and presented in both time and frequency domains. The results show that significant gains are made in the improvement of vehicle performance. Results include a reduction of over 35% in the acceleration peak-to-peak value of a sprung mass over a bumpy road and a reduction of over 24% in the root-mean-square (RMS) sprung mass acceleration over a random road as compared to passive suspension with typical original equipment (OE) shock absorbers. In addition, the semi-active full vehicle system via HSIC based on SMIS provides better isolation than that via the original HSIC, which can avoid the effect of the time delay uncertainty of the MR dampers

  3. Studying mixing in Non-Newtonian blue maize flour suspensions using color analysis.

    Directory of Open Access Journals (Sweden)

    Grissel Trujillo-de Santiago

    Full Text Available BACKGROUND: Non-Newtonian fluids occur in many relevant flow and mixing scenarios at the lab and industrial scale. The addition of acid or basic solutions to a non-Newtonian fluid is not an infrequent operation, particularly in Biotechnology applications where the pH of Non-Newtonian culture broths is usually regulated using this strategy. METHODOLOGY AND FINDINGS: We conducted mixing experiments in agitated vessels using Non-Newtonian blue maize flour suspensions. Acid or basic pulses were injected to reveal mixing patterns and flow structures and to follow their time evolution. No foreign pH indicator was used as blue maize flours naturally contain anthocyanins that act as a native, wide spectrum, pH indicator. We describe a novel method to quantitate mixedness and mixing evolution through Dynamic Color Analysis (DCA in this system. Color readings corresponding to different times and locations within the mixing vessel were taken with a digital camera (or a colorimeter and translated to the CIELab scale of colors. We use distances in the Lab space, a 3D color space, between a particular mixing state and the final mixing point to characterize segregation/mixing in the system. CONCLUSION AND RELEVANCE: Blue maize suspensions represent an adequate and flexible model to study mixing (and fluid mechanics in general in Non-Newtonian suspensions using acid/base tracer injections. Simple strategies based on the evaluation of color distances in the CIELab space (or other scales such as HSB can be adapted to characterize mixedness and mixing evolution in experiments using blue maize suspensions.

  4. Development of Matlab Simulink model for dynamics analysis of passive suspension system for lightweight vehicle

    Science.gov (United States)

    Jamali, M. S.; Ismail, K. A.; Taha, Z.; Aiman, M. F.

    2017-10-01

    In designing suitable isolators to reduce unwanted vibration in vehicles, the response from a mathematical model which characterizes the transmissibility ratio of the input and output of the vehicle is required. In this study, a Matlab Simulink model is developed to study the dynamic behaviour performance of passive suspension system for a lightweight electric vehicle. The Simulink model is based on the two degrees of freedom system quarter car model. The model is compared to the theoretical plots of the transmissibility ratios between the amplitudes of the displacements and accelerations of the sprung and unsprung masses to the amplitudes of the ground, against the frequencies at different damping values. It was found that the frequency responses obtained from the theoretical calculations and from the Simulink simulation is comparable to each other. Hence, the model may be extended to a full vehicle model.

  5. Compressed Air Production Using Vehicle Suspension

    OpenAIRE

    Ninad Arun Malpure; Sanket Nandlal Bhansali

    2015-01-01

    Abstract Generally compressed air is produced using different types of air compressors which consumes lot of electric energy and is noisy. In this paper an innovative idea is put forth for production of compressed air using movement of vehicle suspension which normal is wasted. The conversion of the force energy into the compressed air is carried out by the mechanism which consists of the vehicle suspension system hydraulic cylinder Non-return valve air compressor and air receiver. We are co...

  6. A Microsphere-Based Suspension Array for Blood Group Molecular Typing: An Update.

    Science.gov (United States)

    Drago, Francesca; Karpasitou, Katerina; Spinardi, Laura; Crespiatico, Loretta; Scalamogna, Mario; Poli, Francesca

    2010-01-01

    SUMMARY: BACKGROUND: In a previous publication we described a method for Jk(a)/Jk(b), Fy(a)/Fy(b), S/s, K/k, Kp(a)/Kp(b), Js(a)/Js(b), Co(a)/Co(b), and Lu(a)/Lu(b) genotyping based on a microsphere suspension array. Here, an improved version of the assay is presented. METHODS: TWO MULTIPLEX POLYMERASE CHAIN REACTIONS (PCR) WERE DEVELOPED: one for amplification of samples routinely tested and the other for those systems that are tested less frequently. Each biotinylated PCR product is hybridized in a single multiplex assay. A total of 2,020 samples were analyzed, and the genotypes were compared to the blood group phenotypes. RESULTS: There have been no discrepancies with the serology results other than null and/or weak phenotypes. CONCLUSION: In its present form, the method presented here has the capacity to genotype hundreds of a samples in few hours with a high concordance rate with serology.

  7. A Noise-Insensitive Semi-Active Air Suspension for Heavy-Duty Vehicles with an Integrated Fuzzy-Wheelbase Preview Control

    Directory of Open Access Journals (Sweden)

    Zhengchao Xie

    2013-01-01

    Full Text Available Semi-active air suspension is increasingly used on heavy-duty vehicles due to its capabilities of consuming less power and low cost and providing better ride quality. In this study, a new low cost but effective approach, fuzzy-wheelbase preview controller with wavelet denoising filter (FPW, is developed for semi-active air suspension system. A semi-active suspension system with a rolling lobe air spring is firstly modeled and a novel front axle vertical acceleration-based road prediction model is constructed. By adopting a sensor on the front axle, the road prediction model can predict more reliable road information for the rear wheel. After filtering useless signal noise, the proposed FPW can generate a noise-insensitive control damping force. Simulation results show that the ride quality, the road holding, the handling capability, the road friendliness, and the comprehensive performance of the semi-active air suspension with FPW outperform those with the traditional active suspension with PID-wheelbase preview controller (APP. It can also be seen that, with the addition of the wavelet filter, the impact of sensor noise on the suspension performance can be minimized.

  8. Crust formation in drying colloidal suspensions

    KAUST Repository

    Style, R. W.

    2010-06-30

    During the drying of colloidal suspensions, the desiccation process causes the suspension near the air interface to consolidate into a connected porous matrix or crust. Fluid transport in the porous medium is governed by Darcy\\'s law and the equations of poroelasticity, while the equations of colloid physics govern processes in the suspension. We derive new equations describing this process, including unique boundary conditions coupling the two regions, yielding a moving-boundary model of the concentration and stress profiles during drying. A solution is found for the steady-state growth of a nedimensional crust during constant evaporation rate from the surface. The solution is used to demonstrate the importance of the system boundary conditions on stress profiles and diffusivity in a drying crust. © 2011 The Royal Society.

  9. Decoupling control of vehicle chassis system based on neural network inverse system

    Science.gov (United States)

    Wang, Chunyan; Zhao, Wanzhong; Luan, Zhongkai; Gao, Qi; Deng, Ke

    2018-06-01

    Steering and suspension are two important subsystems affecting the handling stability and riding comfort of the chassis system. In order to avoid the interference and coupling of the control channels between active front steering (AFS) and active suspension subsystems (ASS), this paper presents a composite decoupling control method, which consists of a neural network inverse system and a robust controller. The neural network inverse system is composed of a static neural network with several integrators and state feedback of the original chassis system to approach the inverse system of the nonlinear systems. The existence of the inverse system for the chassis system is proved by the reversibility derivation of Interactor algorithm. The robust controller is based on the internal model control (IMC), which is designed to improve the robustness and anti-interference of the decoupled system by adding a pre-compensation controller to the pseudo linear system. The results of the simulation and vehicle test show that the proposed decoupling controller has excellent decoupling performance, which can transform the multivariable system into a number of single input and single output systems, and eliminate the mutual influence and interference. Furthermore, it has satisfactory tracking capability and robust performance, which can improve the comprehensive performance of the chassis system.

  10. Mesoscopic electrohydrodynamic simulations of binary colloidal suspensions

    Science.gov (United States)

    Rivas, Nicolas; Frijters, Stefan; Pagonabarraga, Ignacio; Harting, Jens

    2018-04-01

    A model is presented for the solution of electrokinetic phenomena of colloidal suspensions in fluid mixtures. We solve the discrete Boltzmann equation with a Bhatnagar-Gross-Krook collision operator using the lattice Boltzmann method to simulate binary fluid flows. Solvent-solvent and solvent-solute interactions are implemented using a pseudopotential model. The Nernst-Planck equation, describing the kinetics of dissolved ion species, is solved using a finite difference discretization based on the link-flux method. The colloids are resolved on the lattice and coupled to the hydrodynamics and electrokinetics through appropriate boundary conditions. We present the first full integration of these three elements. The model is validated by comparing with known analytic solutions of ionic distributions at fluid interfaces, dielectric droplet deformations, and the electrophoretic mobility of colloidal suspensions. Its possibilities are explored by considering various physical systems, such as breakup of charged and neutral droplets and colloidal dynamics at either planar or spherical fluid interfaces.

  11. Rheology of dense suspensions of non colloidal particles

    Directory of Open Access Journals (Sweden)

    Guazzelli Élisabeth

    2017-01-01

    Full Text Available Dense suspensions are materials with broad applications both in industrial processes (e.g. waste disposal, concrete, drilling muds, metalworking chip transport, and food processing and in natural phenomena (e.g. flows of slurries, debris, and lava. Despite its long research history and its practical relevance, the mechanics of dense suspensions remain poorly understood. The major difficulty is that the grains interact both by hydrodynamic interactions through the liquid and by mechanical contact. These systems thus belong to an intermediate regime between pure suspensions and granular flows. We show that we can unify suspension and granular rheology under a common framework by transferring the frictional approach of dry granular media to wet suspensions of spherical particles. We also discuss non-Newtonian behavior such as normal-stress differences and shear-induced migration. Beyond the classical problem of dense suspension of hard spheres which is far from being completely resolved, there are also entirely novel avenues of study concerning more complex mixtures of particles and fluids such as those involving other types of particles (e.g. fibers or non-Newtonian fluids that we will also address.

  12. Pt based PEMFC catalysts prepared from colloidal particle suspensions--a toolbox for model studies.

    Science.gov (United States)

    Speder, Jozsef; Altmann, Lena; Roefzaad, Melanie; Bäumer, Marcus; Kirkensgaard, Jacob J K; Mortensen, Kell; Arenz, Matthias

    2013-03-14

    A colloidal synthesis approach is presented that allows systematic studies of the properties of supported proton exchange membrane fuel cell (PEMFC) catalysts. The applied synthesis route is based on the preparation of monodisperse nanoparticles in the absence of strong binding organic stabilizing agents. No temperature post-treatment of the catalyst is required rendering the synthesis route ideally suitable for comparative studies. We report work concerning a series of catalysts based on the same colloidal Pt nanoparticle (NP) suspension, but with different high surface area (HSA) carbon supports. It is shown that for the prepared catalysts the carbon support has no catalytic co-function, but carbon pre-treatment leads to enhanced sticking of the Pt NPs on the support. An unwanted side effect, however, is NP agglomeration during synthesis. By contrast, enhanced NP sticking without agglomeration can be accomplished by the addition of an ionomer to the NP suspension. The catalytic activity of the prepared catalysts for the oxygen reduction reaction is comparable to industrial catalysts and no influence of the particle size is found in the range of 2-5 nm.

  13. Multiobjective suspension control problem

    NARCIS (Netherlands)

    Jager, de A.G.

    1995-01-01

    The paper describes a (controller) design problem in the field of suspension systems for transport vehicles. A ten degrees-of-freedom model for a tractor-semitrailer vehicle is presented, using parameters derived from a real vehicle, which should be used for design and verification purposes. Road

  14. Spectral analysis connected with suspension bridge systems

    Czech Academy of Sciences Publication Activity Database

    Malík, Josef

    2016-01-01

    Roč. 81, č. 1 (2016), s. 42-75 ISSN 0272-4960 R&D Projects: GA MŠk ED2.1.00/03.0082 Institutional support: RVO:68145535 Keywords : suspension bridge * vertical and torsional oscillation * eigenvalue * eigenvector * flutter Subject RIV: JM - Building Engineering Impact factor: 0.945, year: 2016 http://imamat.oxfordjournals.org/content/early/2015/09/16/imamat.hxv027.short?rss=1

  15. Minimally invasive brow suspension for facial paralysis.

    Science.gov (United States)

    Costantino, Peter D; Hiltzik, David H; Moche, Jason; Preminger, Aviva

    2003-01-01

    To report a new technique for unilateral brow suspension for facial paralysis that is minimally invasive, limits supraciliary scar formation, does not require specialized endoscopic equipment or expertise, and has proved to be equal to direct brow suspension in durability and symmetry. Retrospective survey of a case series of 23 patients between January 1997 and December 2000. Metropolitan tertiary care center. Patients with head and neck tumors and brow ptosis caused by facial nerve paralysis. The results of the procedure were determined using the following 3-tier rating system: outstanding (excellent elevation and symmetry); acceptable (good elevation and fair symmetry); and unacceptable (loss of elevation). The results were considered outstanding in 12 patients, acceptable in 9 patients, and unacceptable in only 1 patient. One patient developed a hematoma, and 1 patient required a secondary adjustment. The technique has proved to be superior to standard brow suspension procedures with regard to scar formation and equal with respect to facial symmetry and suspension. These results have caused us to abandon direct brow suspension and to use this minimally invasive method in all cases of brow ptosis due to facial paralysis.

  16. Particle interactions in concentrated suspensions

    International Nuclear Information System (INIS)

    Mondy, L.A.; Graham, A.L.; Abbott, J.R.; Brenner, H.

    1993-01-01

    An overview is presented of research that focuses on slow flows of suspensions in which colloidal and inertial effects are negligibly small. The authors describe nuclear magnetic resonance imaging experiments to quantitatively measure particle migration occurring in concentrated suspensions undergoing a flow with a nonuniform shear rate. These experiments address the issue of how the flow field affects the microstructure of suspensions. In order to understand the local viscosity in a suspension with such a flow-induced, spatially varying concentration, one must know how the viscosity of a homogeneous suspension depends on such variables as solids concentration and particle orientation. The authors suggest the technique of falling ball viscometry, using small balls, as a method to determine the effective viscosity of a suspension without affecting the original microstructure significantly. They also describe data from experiments in which the detailed fluctuations of a falling ball's velocity indicate the noncontinuum nature of the suspension and may lead to more insights into the effects of suspension microstructure on macroscopic properties. Finally, they briefly describe other experiments that can be performed in quiescent suspensions (in contrast to the use of conventional shear rotational viscometers) in order to learn more about boundary effects in concentrated suspensions

  17. Improving the cooling performance of electrical distribution transformer using transformer oil – Based MEPCM suspension

    Directory of Open Access Journals (Sweden)

    Mushtaq Ismael Hasan

    2017-04-01

    Full Text Available In this paper the electrical distribution transformer has been studied numerically and the effect of outside temperature on its cooling performance has been investigated. The temperature range studied covers the hot climate regions. 250 KVA distribution transformer is chosen as a study model. A novel cooling fluid is proposed to improve the cooling performance of this transformer, transformer oil-based microencapsulated phase change materials suspension is used with volume concentration (5–25% as a cooling fluid instead of pure transformer oil. Paraffin wax is used as a phase change material to make the suspension, in addition to the ability of heat absorption due to melting, the paraffin wax considered as a good electrical insulator. Results obtained show that, using of MEPCM suspension instead of pure transformer oil lead to improve the cooling performance of transformer by reducing its temperature and as a consequence increasing its protection against the breakdown. The melting fraction increased with increasing outside temperature up to certain temperature after which the melting fraction reach maximum constant value (MF = 1 which indicate that, the choosing of PCM depend on the environment in which the transformer is used.

  18. Analysis and experimental validation of an HTS linear synchronous propulsion prototype with HTS magnetic suspension

    International Nuclear Information System (INIS)

    Jin Jianxun; Zheng Luhai; Guo Youguang; Xu Wei; Zhu Jianguo

    2011-01-01

    An HTS linear synchronous propulsion prototype with an HTSLSM drive is developed. The feasibility of combining an HTSLSM with an HTS magnetic suspension system has been verified. Three different PMGs are studied by ECS method and experiment verification to obtain an optimal one. The prototype has been tested to obtain the performance and thrust characteristics of the HTSLSM. The measurement results benefit the optimal design and control scheme development for an HTSLSM. A high temperature superconducting (HTS) linear propulsion system composed of a single-sided HTS linear synchronous motor (HTSLSM) in its middle and HTS magnetic suspension sub-systems on both sides has been developed. The HTSLSM uses an HTS bulk magnet array on the moving secondary, and the field-trapped characteristics of the HTS bulk using different magnetized methods have been measured and compared to identify their magnetization capability. In order to generate a large levitation force for the system, three different types of permanent magnet guideways (PMGs) have been numerically analyzed and experimentally verified to obtain an optimal PMG. Based on comprehensive experimental prototype tests, the results show that the HTS linear propulsion system can run with stable magnetic suspension having a constant air-gap length, and the thrust characteristics versus the exciting current, working frequency and the air-gap length have also been obtained. This work forms the basis for developing a practical HTS linear propulsion system by using HTS bulks both for propulsion and suspension.

  19. Monitoring Technology for Vehicle Loading Status Based on the Analysis of Suspension Vibration Characters

    Directory of Open Access Journals (Sweden)

    Shiwu Li

    2014-01-01

    Full Text Available Monitoring and early warning of vehicle risk status was one of the key technologies of transportation security, and real-time monitoring load status could reduce the transportation accidents effectively. In order to obtain vehicle load status information, vehicle characters of suspension were analyzed and simulated under different working conditions. On the basis of this, the device that can detect suspension load with overload protection structure was designed and a method of monitored vehicle load status was proposed. The monitoring platform of vehicle load status was constructed and developed for a FAW truck and system was tested on level-A road and body twist lane. The results show that the measurement error is less than 5% and horizontal centre-of-mass of vehicle was positioned accurately. The platform enables providing technical support for the real-time monitoring and warning of vehicles risk status in transit.

  20. Development of a simulation model of semi-active suspension for monorail

    Science.gov (United States)

    Hasnan, K.; Didane, D. H.; Kamarudin, M. A.; Bakhsh, Qadir; Abdulmalik, R. E.

    2016-11-01

    The new Kuala Lumpur Monorail Fleet Expansion Project (KLMFEP) uses semiactive technology in its suspension system. It is recognized that the suspension system influences the ride quality. Thus, among the way to further improve the ride quality is by fine- tuning the semi-active suspension system on the new KL Monorail. The semi-active suspension for the monorail specifically in terms of improving ride quality could be exploited further. Hence a simulation model which will act as a platform to test the design of a complete suspension system particularly to investigate the ride comfort performance is required. MSC Adams software was considered as the tool to develop the simulation platform, where all parameters and data are represented by mathematical equations; whereas the new KL Monorail being the reference model. In the simulation, the model went through step disturbance on the guideway for stability and ride comfort analysis. The model has shown positive results where the monorail is in stable condition as an outcome from stability analysis. The model also scores a Rating 1 classification in ISO 2631 Ride Comfort performance which is very comfortable as an overall outcome from ride comfort analysis. The model is also adjustable, flexibile and understandable by the engineers within the field for the purpose of further development.

  1. Towards a peptide-based suspension array for the detection of pestivirus antibodies in swine.

    Science.gov (United States)

    van der Wal, Fimme J; Jelsma, Tinka; Fijten, Helmi; Achterberg, René P; Loeffen, Willie L A

    2016-09-01

    Classical swine fever (CSF) is a highly contagious and lethal disease in swine. Serological tests for the diagnosis of CSF need not only to detect antibodies against CSFV, but also need to differentiate these from antibodies against other pestiviruses. To investigate the possibilities of specific peptide-based serology, various synthetic peptides that represent a well-described linear epitope of the CSFV E2 protein (TAVSPTTLR) were used to test the viability of a peptide-based suspension array for the detection of antibodies against pestiviruses in swine. The results show that N-terminally biotinylated peptides can bind to avidin conjugated beads, and function in detection of the corresponding monoclonal antibody WH303. There are indications that the length of the spacer between epitope and biotin affect the efficiency of the peptide-antibody interaction. A protocol was established that enables probing for antibodies in porcine sera, where neutravidin-blocking of serum and the use of empty control beads for normalization was crucial. With a set of porcine sera with antibodies against various pestiviruses, the proof of concept of a peptide-based suspension array for specific detection of antibodies against pestiviruses in porcine sera was demonstrated. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  2. Superconducting electromagnets for large wind tunnel magnetic suspension and balance systems

    International Nuclear Information System (INIS)

    Boom, R.W.; Abdelsalam, M.K.; Bakerek, K.

    1985-01-01

    This paper presents a new design study of a Magnetic Suspension and Balance System (MSBS) for airplane models in a large 8 ft x 8 ft wind tunnel. New developments in the design include: use of a superconducting solenoid as a model core instead of magnetized iron; combination of permanent magnet material in the model wings along with four race-track coils to produce the required roll torque; and mounting of all the magnets in an integral cold structure instead of in separate cryostats. Design of superconducting solenoid model cores and practical experience with a small-scale prototype are discussed

  3. Robust non-fragile finite-frequency H∞ static output-feedback control for active suspension systems

    Science.gov (United States)

    Wang, Gang; Chen, Changzheng; Yu, Shenbo

    2017-07-01

    This paper deals with the problem of non-fragile H∞ static output-feedback control of vehicle active suspension systems with finite-frequency constraint. The control objective is to improve ride comfort within the given frequency range and ensure the hard constraints in the time-domain. Moreover, in order to enhance the robustness of the controller, the control gain perturbation is also considered in controller synthesis. Firstly, a new non-fragile H∞ finite-frequency control condition is established by using generalized Kalman-Yakubovich-Popov (GKYP) lemma. Secondly, the static output-feedback control gain is directly derived by using a non-iteration algorithm. Different from the existing iteration LMI results, the static output-feedback design is simple and less conservative. Finally, the proposed control algorithm is applied to a quarter-car active suspension model with actuator dynamics, numerical results are made to show the effectiveness and merits of the proposed method.

  4. Investigating high-concentration monoclonal antibody powder suspension in nonaqueous suspension vehicles for subcutaneous injection.

    Science.gov (United States)

    Bowen, Mayumi; Armstrong, Nick; Maa, Yuh-Fun

    2012-12-01

    Developing high-concentration monoclonal antibody (mAb) liquid formulations for subcutaneous (s.c.) administration is challenging because increased viscosity makes injection difficult. To overcome this obstacle, we investigated a nonaqueous powder suspension approach. Three IgG1 mAbs were spray dried and suspended at different concentrations in Miglyol® 840, benzyl benzoate, or ethyl lactate. Suspensions were characterized for viscosity, particle size, and syringeability; physical stability was visually inspected. Suspensions generally outperformed liquid solutions for injectability despite higher viscosity at the same mAb concentrations. Powder formulations and properties had little effect on viscosity or injectability. Ethyl lactate suspensions had lowest viscosity (Miglyol® 840 improved overall performance in high mAb concentration suspensions. This study demonstrated the viability of high mAb concentration (>300 mg/mL) in suspension formulations for s.c. administration. Copyright © 2012 Wiley Periodicals, Inc.

  5. DC electrophoresis and viscosity of realistic salt-free concentrated suspensions: non-equilibrium dissociation-association processes.

    Science.gov (United States)

    Ruiz-Reina, Emilio; Carrique, Félix; Lechuga, Luis

    2014-03-01

    Most of the suspensions usually found in industrial applications are concentrated, aqueous and in contact with the atmospheric CO2. The case of suspensions with a high concentration of added salt is relatively well understood and has been considered in many studies. In this work we are concerned with the case of concentrated suspensions that have no ions different than: (1) those stemming from the charged colloidal particles (the added counterions, that counterbalance their surface charge); (2) the H(+) and OH(-) ions from water dissociation, and (3) the ions generated by the atmospheric CO2 contamination. We call this kind of systems "realistic salt-free suspensions". We show some theoretical results about the electrophoretic mobility of a colloidal particle and the electroviscous effect of realistic salt-free concentrated suspensions. The theoretical framework is based on a cell model that accounts for particle-particle interactions in concentrated suspensions, which has been successfully applied to many different phenomena in concentrated suspensions. On the other hand, the water dissociation and CO2 contamination can be described following two different levels of approximation: (a) by local equilibrium mass-action equations, because it is supposed that the reactions are so fast that chemical equilibrium is attained everywhere in the suspension, or (b) by non-equilibrium dissociation-association kinetic equations, because it is considered that some reactions are not rapid enough to ensure local chemical equilibrium. Both approaches give rise to different results in the range from dilute to semidilute suspensions, causing possible discrepancies when comparing standard theories and experiments concerning transport properties of realistic salt-free suspensions. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. Nonlinear reset integrator control design: Application to the active suspension control of vehicles

    OpenAIRE

    Acho Zuppa, Leonardo

    2014-01-01

    We present an unexampled reset integrator control design based on the Clegg integrator system. Using an appropriate mathematical model of our Clegg integrator controller, stability proof of the closed-loop system applied to the vibration control problem of a second-order system is shown without invoking hybrid system theory. Furthermore, we illustrate the pplicability of our controller, from the numerical experiment point of view, to the suspension vibration control of vehicles.

  7. Suspension trauma; Le traumatisme de suspension

    Energy Technology Data Exchange (ETDEWEB)

    Trudel, S. [Le Centre de sante et de services sociaux du rocher Perce, Chandler, PQ (Canada)

    2010-07-01

    This presentation discussed the precautions that should be taken to avoid falls from wind turbines or transmission towers. Suspension trauma was explained by a medical doctor in terms of physiology and the body's normal circulation and the elements that disturb normal physiology when in suspension. The trauma occurs following a fall, which carries the risk of 1or more disorders, such as massive hemorrhage, high cardiac pulse, and constriction of blood vessels. Nausea, vertigo, cardiac arrhythmia and sweating occur 15 to 20 minutes following the fall. The presentation emphasized the importance of having qualified personnel at the site and wearing proper harnesses and equipment that supports the neck. figs.

  8. Liquid crystalline phases in suspensions of pigments in non-polar solvents

    Science.gov (United States)

    Klein, Susanne; Richardson, Robert M.; Eremin, Alexey

    We will discuss colloid suspensions of pigments and compare their electro-optic properties with those of traditional dyed low molecular weight liquid crystal systems. There are several potential advantages of colloidal suspensions over low molecular weight liquid crystal systems: a very high contrast because of the high orientational order parameter of suspensions of rod shaped nano-particles, the excellent light fastness of pigments as compared to dyes and high colour saturations resulting from the high loading of the colour stuff. Although a weak `single-particle' electro-optic response can be observed in dilute suspensions, the response is very much enhanced when the concentration of the particles is sufficient to lead to a nematic phase. Excellent stability of suspensions is beneficial for experimental observation and reproducibility, but it is a fundamental necessity for display applications. We therefore discuss a method to achieve long term stability of dispersed pigments and the reasons for its success. Small angle X-ray scattering was used to determine the orientational order parameter of the suspensions as a function of concentration and the dynamic response to an applied electric field. Optical properties were investigated for a wide range of pigment concentrations. Electro-optical phenomena, such as field-induced birefringence and switching, were characterised. In addition, mixtures of pigment suspensions with small amounts of ferrofluids show promise as future magneto-optical materials.

  9. Nonlinear Modeling and Coordinate Optimization of a Semi-Active Energy Regenerative Suspension with an Electro-Hydraulic Actuator

    Directory of Open Access Journals (Sweden)

    Farong Kou

    2018-01-01

    Full Text Available In order to coordinate the damping performance and energy regenerative performance of energy regenerative suspension, this paper proposes a structure of a vehicle semi-active energy regenerative suspension with an electro-hydraulic actuator (EHA. In light of the proposed concept, a specific energy regenerative scheme is designed and a mechanical properties test is carried out. Based on the test results, the parameter identification for the system model is conducted using a recursive least squares algorithm. On the basis of the system principle, the nonlinear model of the semi-active energy regenerative suspension with an EHA is built. Meanwhile, linear-quadratic-Gaussian control strategy of the system is designed. Then, the influence of the main parameters of the EHA on the damping performance and energy regenerative performance of the suspension is analyzed. Finally, the main parameters of the EHA are optimized via the genetic algorithm. The test results show that when a sinusoidal is input at the frequency of 2 Hz and the amplitude of 30 mm, the spring mass acceleration root meam square value of the optimized EHA semi-active energy regenerative suspension is reduced by 22.23% and the energy regenerative power RMS value is increased by 40.51%, which means that while meeting the requirements of vehicle ride comfort and driving safety, the energy regenerative performance is improved significantly.

  10. Adaptive magnetorheological seat suspension for the expeditionary fighting vehicle

    International Nuclear Information System (INIS)

    Hiemenz, G J; Hu, W; Wereley, N M

    2009-01-01

    The Expeditionary Fighting Vehicle (EFV) is an amphibious vehicle designed to operate through harsh conditions and at much higher speeds than its predecessors. These unique capabilities and broadly varying operational conditions lead to a complex design and human factors scenario for the forward seating positions that cannot be solved using conventional passive seat suspension systems. Injurious shock loads transmitted to the occupants when traversing over water in high sea states and/or at high speeds, as well as harmful shock and vibration transmitted to the occupants when the vehicle is travelling over land, pose a threat to occupant health and significantly limit mission duration. In this study, a semi-active magnetorheological (MR) seat suspension is developed which adapts to broadly varying operational conditions, as well as occupant weight, to provide optimal protection of EFV occupants. It is shown that this MR seat suspension system will reduce the shock and vibration transmitted to the occupant by up to 33% and 65%, respectively, as compared to the existing passive suspension.

  11. Adaptive magnetorheological seat suspension for the expeditionary fighting vehicle

    Energy Technology Data Exchange (ETDEWEB)

    Hiemenz, G J [Techno-Sciences, Inc., 11750 Beltsville Dr. Ste. 300, Beltsville, MD 20705 (United States); Hu, W; Wereley, N M [Aerospace Engineering, University of Maryland, College Park, MD 20712 (United States)], E-mail: greg@technosci.com, E-mail: wereley@umd.edu

    2009-02-01

    The Expeditionary Fighting Vehicle (EFV) is an amphibious vehicle designed to operate through harsh conditions and at much higher speeds than its predecessors. These unique capabilities and broadly varying operational conditions lead to a complex design and human factors scenario for the forward seating positions that cannot be solved using conventional passive seat suspension systems. Injurious shock loads transmitted to the occupants when traversing over water in high sea states and/or at high speeds, as well as harmful shock and vibration transmitted to the occupants when the vehicle is travelling over land, pose a threat to occupant health and significantly limit mission duration. In this study, a semi-active magnetorheological (MR) seat suspension is developed which adapts to broadly varying operational conditions, as well as occupant weight, to provide optimal protection of EFV occupants. It is shown that this MR seat suspension system will reduce the shock and vibration transmitted to the occupant by up to 33% and 65%, respectively, as compared to the existing passive suspension.

  12. Weakly sheared active suspensions: hydrodynamics, stability, and rheology.

    Science.gov (United States)

    Cui, Zhenlu

    2011-03-01

    We present a kinetic model for flowing active suspensions and analyze the behavior of a suspension subjected to a weak steady shear. Asymptotic solutions are sought in Deborah number expansions. At the leading order, we explore the steady states and perform their stability analysis. We predict the rheology of active systems including an activity thickening or thinning behavior of the apparent viscosity and a negative apparent viscosity depending on the particle type, flow alignment, and the anchoring conditions, which can be tested on bacterial suspensions. We find remarkable dualities that show that flow-aligning rodlike contractile (extensile) particles are dynamically and rheologically equivalent to flow-aligning discoid extensile (contractile) particles for both tangential and homeotropic anchoring conditions. Another key prediction of this work is the role of the concentration of active suspensions in controlling the rheological behavior: the apparent viscosity may decrease with the increase of the concentration.

  13. ELASTO-KINEMATIC COMPUTATIONAL MODEL OF SUSPENSION WITH FLEXIBLE SUPPORTING ELEMENTS

    Directory of Open Access Journals (Sweden)

    Tomáš Vrána

    2016-04-01

    Full Text Available This paper analyzes the impact of flexibility of individual supporting elements of independent suspension on its elasto-kinematic characteristics. The toe and camber angle are the geometric parameters of the suspension, which waveforms and their changes under the action of vertical, longitudinal and transverse forces affect the stability of the vehicle. To study these dependencies, the computational multibody system (MBS model of axle suspension in the system HyperWorks is created. There are implemented Finite-Element-Method (FEM models reflecting the flexibility of the main supporting elements. These are subframe, the longitudinal arms, transverse arms and knuckle. Flexible models are developed using Component Mode Synthesis (CMS by Craig-Bampton. The model further comprises force elements, such as helical springs, shock absorbers with a stop of the wheel and the anti-roll bar. Rubber-metal bushings are modeled flexibly, using nonlinear deformation characteristics. Simulation results are validated by experimental measurements of geometric parameters of real suspension.

  14. A magneto rheological hybrid damper for railway vehicles suspensions

    Directory of Open Access Journals (Sweden)

    Gheorghe GHITA

    2012-09-01

    Full Text Available High speed railway vehicles features a specific lateral oscillation resulting from the coupled lateral displacement and yaw of the wheelset which leads to a sinusoid movement of the wheelset along the track, transferred to the entire vehicle. The amplitude of this oscillation is strongly dependant on vehicle’s velocity. Over a certain value, namely the critical speed, the instability phenomenon so-called hunting occurs. To raise the vehicle’s critical speed different designs of the suspension all leading to a much stiffer vehicle can be envisaged. Different simulations prove that a stiffer central suspension will decrease the passenger’s comfort in terms of lateral accelerations of the carboy. The authors propose a semi-active magneto rheological suspension to improve the vehicle’s comfort at high speeds. The suspension has as executive elements hybrid magneto rheological dampers operating under sequential control strategy type balance logic. Using an original mathematical model for the lateral dynamics of the vehicle the responses of the system with passive and semi-active suspensions are simulated. It is shown that the semi-active suspension can improve the vehicle performances.

  15. A numerical study on the structural integrity of self-anchored cable-stayed suspension bridges

    Directory of Open Access Journals (Sweden)

    Paolo Lonetti

    2016-10-01

    Full Text Available A generalized numerical model for predicting the structural integrity of self-anchored cable-stayed suspension bridges considering both geometric and material nonlinearities is proposed. The bridge is modeled by means of a 3D finite element approach based on a refined displacement-type finite element approximation, in which geometrical nonlinearities are assumed in all components of the structure. Moreover, nonlinearities produced by inelastic material and second order effects in the displacements are considered for girder and pylon elements, which combine gradual yielding theory with CRC tangent modulus concept. In addition, for the elements of the suspension system, i.e. stays, hangers and main cable, a finite plasticity theory is adopted to fully evaluate both geometric and material nonlinearities. In this framework, the influence of geometric and material nonlinearities on the collapse bridge behavior is investigated, by means of a comparative study, which identifies the effects produced on the ultimate bridge behavior of several sources of bridge nonlinearities involved in the bridge components. Results are developed with the purpose to evaluate numerically the influence of the material and geometric characteristics of self-anchored cable-stayed suspension bridges with respect also to conventional bridge based on cablestayed or suspension schemes

  16. Suspension, a Wake-Up Call: Rural Educators' Attitudes toward Suspension.

    Science.gov (United States)

    Henderson, Joan; Friedland, Billie

    Data from the West Virginia Department of Education reveals that from September 1991 to January 1992, school districts reported 18,915 out-of-school suspensions involving 12,997 students. In 1995, the West Virginia State Legislature enacted the Safe Schools Act, which specifically mandates suspension for no less than 12 consecutive months for…

  17. Effect of carboxymethyl cellulose and ionic strength on stability of mineral suspensions in potash ore flotation systems.

    Science.gov (United States)

    Pawlik, M; Laskowski, J S; Ansari, A

    2003-04-15

    The adsorption of sodium carboxymethyl cellulose from aqueous solutions varying in ionic strength from that of distilled water to 50% NaCl/KCl brine (about 3.5 mol/dm(3)) onto illite and dolomite has been studied. The purpose of this work was to investigate the solvency effects in the phenomena underlying the potash flotation process that is carried out in saturated brine. Based on viscosity measurements, the adsorption results were analyzed in terms of a simple model of polymer macromolecules in solution. Suspension stability measurements carried out concomitantly with adsorption tests showed the ranges of carboxymethyl cellulose concentration over which the tested suspensions either were aggregated or were restabilized.

  18. Settling of isolated particles and of suspensions in a shear-thinning medium; Sedimentation de particules isolees et de suspensions en milieu rheofluidifiant

    Energy Technology Data Exchange (ETDEWEB)

    Daugan, S.

    2002-11-01

    After drawing up a balance sheet of current knowledge of settling of particles and suspensions in Newtonian and non Newtonian fluids, we introduce the characterisation of the fluid-particles system and especially the shear-thinning behavior of Xanthan solutions. This experimental study is organised into two parts. First of all, we study the settling behavior of a few particles falling along their line of centres. The conditions for particles aggregation with respect to the rheological properties of the suspending fluid are systematically reported. To that extent, rheological relaxation experiments are performed. Once aggregated, the particles velocities are much more important that the velocity of a single one. We show that a simple model, based on the Newtonian case, allows to predict the position and the velocity of each particle with respect to the initial separation distance between them. The second part of this work is devoted to the study of the settling behavior of spherical and monodisperse particles suspensions according to the particles volume fraction, the polymer concentration of the suspending fluid and the geometry of the sedimenting cell. From a model giving the particle volume fraction as a function of the luminous intensity transmitted by the suspension, we show that three regimes of different kinetics occur. During the second regime, the particle volume fraction decreases exponentially with time and the observed phenomena are very fast. Finally, we study the spatial structuration of the suspension and we link it to the topography of the sediment obtained at the end of the sedimentation. (author)

  19. Qualification criteria verification for aisi-4340 steel suspension lug

    International Nuclear Information System (INIS)

    Riaz, M.A.; Alam, M.

    2005-01-01

    All external loads carried underneath an aircraft are mounted onto it through mechanism generally known as suspension system. The externally mounted attachments like bombs, missiles and fuel tanks etc. experience enormous aerodynamic and inertial forces in the flights. These forces are transferred to the interface point of suspension system, known as 'Suspension Lug'. Thus lugs are considered critical component and have extremely stringent qualification criteria standards used in the aviation industry in USA, Europe, Russia, etc. Different standards prevail in different parts of the world about qualification and testing of these lugs. As Pakistan is entering into aviation industry, therefore there is a need to fulfill the requirements of these standards, to suit Pakistani environment. The suspension lug under study is 2000 Ibs. load class made from AISI-4340 Steel having good mechanical properties as per required standard. The manufacturing processes included forging, machining and vacuum heat treatment. The prototypes of suspension lugs were manufactured in the local industry and subjected to the required mechanical tests such as tensile testing at 5 to 35 degree angles. Impact testing at cryogenic temperatures of -50 to -70 degree C, and breaking load testing were performed. The acceptable results were obtained and mechanical testing for qualification of lugs was finalized and standardized. The options were compared with practical viability, utilization of product and cost effectiveness. (author)

  20. Effect of flexibility on the growth of concentration fluctuations in a suspension of sedimenting fibers: Particle simulations

    Energy Technology Data Exchange (ETDEWEB)

    Manikantan, Harishankar; Saintillan, David [Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California 92093 (United States)

    2016-01-15

    Three-dimensional numerical simulations are performed to study the stability of a sedimenting suspension of weakly flexible fibers. It is well known that a suspension of rigid rods sedimenting under gravity at low Reynolds number is unstable to concentration fluctuations owing to hydrodynamic interactions. Flexible fibers, however, reorient while settling and even weak flexibility can alter their collective dynamics. In our recent work [Manikantan et al., “The instability of a sedimenting suspension of weakly flexible fibres,” J. Fluid Mech. 756, 935–964 (2014)], we developed a mean-field theory to predict the linear stability of such a system. Here, we verify these predictions using accurate and efficient particle simulations based on a slender-body model. We also demonstrate the mechanisms by which flexibility-induced reorientation alters suspension microstructure, and through it, its stability. Specifically, we first show that the anisotropy of the base state in the case of a suspension of flexible fibers has a destabilizing effect compared to a suspension of rigid rods. Second, a conflicting effect of flexibility is also shown to suppress particle clustering and slow down the growth of the instability. The relative magnitude of filament flexibility and rotational Brownian motion dictates which effect dominates, and our simulations qualitatively follow theoretically predicted trends. The mechanism for either effects is tied to the flexibility-induced reorientation of particles, which we illustrate using velocity and orientation statistics from our simulations. Finally, we also show that, in the case of an initially homogeneous and isotropic suspension, flexibility always acts to suppress the growth of the instability.

  1. Effect of flexibility on the growth of concentration fluctuations in a suspension of sedimenting fibers: Particle simulations

    International Nuclear Information System (INIS)

    Manikantan, Harishankar; Saintillan, David

    2016-01-01

    Three-dimensional numerical simulations are performed to study the stability of a sedimenting suspension of weakly flexible fibers. It is well known that a suspension of rigid rods sedimenting under gravity at low Reynolds number is unstable to concentration fluctuations owing to hydrodynamic interactions. Flexible fibers, however, reorient while settling and even weak flexibility can alter their collective dynamics. In our recent work [Manikantan et al., “The instability of a sedimenting suspension of weakly flexible fibres,” J. Fluid Mech. 756, 935–964 (2014)], we developed a mean-field theory to predict the linear stability of such a system. Here, we verify these predictions using accurate and efficient particle simulations based on a slender-body model. We also demonstrate the mechanisms by which flexibility-induced reorientation alters suspension microstructure, and through it, its stability. Specifically, we first show that the anisotropy of the base state in the case of a suspension of flexible fibers has a destabilizing effect compared to a suspension of rigid rods. Second, a conflicting effect of flexibility is also shown to suppress particle clustering and slow down the growth of the instability. The relative magnitude of filament flexibility and rotational Brownian motion dictates which effect dominates, and our simulations qualitatively follow theoretically predicted trends. The mechanism for either effects is tied to the flexibility-induced reorientation of particles, which we illustrate using velocity and orientation statistics from our simulations. Finally, we also show that, in the case of an initially homogeneous and isotropic suspension, flexibility always acts to suppress the growth of the instability

  2. Wheeled Vehicle Drive Lines, Axles, and Suspension Systems. Military Curriculum Materials for Vocational and Technical Education.

    Science.gov (United States)

    Army Ordnance Center and School, Aberdeen Proving Ground, MD.

    This course is one of several subcourses that make up the entire Army correspondence course on wheeled vehicle maintenance. The subcourse is designed to provide the student with information about the operation, malfunction diagnosis, maintenance, and repair of wheeled vehicle drive lines, axles, and suspension systems. It provides the basic…

  3. Electrohydrodynamics of suspension of liquid drops in AC fields

    Science.gov (United States)

    Abdul Halim, Md.; Esmaeeli, Asghar

    2012-11-01

    Manipulation of liquid drops by an externally applied electric field is currently the focus of increased attention because of its relevance in a broad range of industrial processes. The effect of a uniform DC electric field on a solitary drop is well studied; however, less is know about the impact of electric field on suspension of liquid drops, and very little information is available on the impact of AC field on a single or a suspension of drops. Here we report the results of Direct Numerical Simulations of electrohydrodynamics of suspension of liquid drops. The governing equations are solved using a front tracking/finite difference technique, in conjunction with Taylor's leaky dielectric model. The imposed electric potential comprises of two parts, a time-independent base and a time-dependent part. The goal is to explore the relative importance of these two components in setting the statistically steady state behavior of the suspension. To this end, we report the results of three sets of simulations, where (i) the time-dependent part act as a perturbation on the base potential, (ii) the two components are of the same order, and (iii) the time-dependent part is much larger than the base potential. The problem is studied as a function of the governing nondimensional parameters.

  4. IMPROVEMENT OF BUS OPERATIONAL CHARACTERISTICS WHILE USING INTEGRATED CONTROL OF SUSPENSION AND TRANSMISSION

    Directory of Open Access Journals (Sweden)

    V. V. Mikhailau

    2016-01-01

    Full Text Available Semi-natural tests for active pneumatic suspension of a 18-tonne tourist bus with the system of automatic body stabilization of the mobile machine and feed-back coupling according to kinematics parameter. The test have been executed in the cases when the bus is stocked with an automatic hydro-mechanical transmission in the process of speed picking up, gear-changing or road braking which is assigned by accidental road humps. A computer simulation of dynamic structures in combination with virtual devices and real objects (HIL – Hardware-in-the-Loop Simulation has been carried in the paper. Personal computers, software, programmed logic controller, frequency generator, solenoid-operated valve have been used for the investigation process. The paper proposes an unconventional method for improvement operational characteristics which is based on integrated control of a suspension and automatic hydro-mechanical transmission. A mathematical model includes systems of automatic transmission, suspension and module for generation of accidental road humps. The model has been considered as a basis for semi-natural laboratory bench with industrially-manufactured controller, other components of automatic systems and standard control organs. The most efficient method for body stabilization is control of the suspension according to the parameter of angular rate during vertical turn of an automobile’s center line with a turning point in the center of mass. The developed algorithm and stabilization system according to angular rate of body’s center line turning have made it possible to improve dynamics of the bus while making gear-changing and to reduce fuel consumption during starting-up and speed picking-up processes. During the braking process such system simultaneously decreases oscillation amplitude of some parameters more than two-fold.

  5. The Electromechanical Low-Power Active Suspension: Modeling, Control, and Prototype Testing

    NARCIS (Netherlands)

    Evers, W.J.E.; Teerhuis, A.P.; Knaap, van der A.C.M.; Besselink, I.J.M.; Nijmeijer, H.

    2011-01-01

    The high energy consumption of market-ready active suspension systems is the limiting factor in the competition with semi-active devices. The variable geometry active suspension is an alternative with a significantly lower power consumption. However, previous designs suffer from packaging problems,

  6. The electromechanical low-power active suspension: modeling, control, and prototype testing

    NARCIS (Netherlands)

    Evers, W.J.; Teerhuis, A.P.; Knaap, A. van der; Besselink, I.; Nijmeijer, H.

    2011-01-01

    The high energy consumption of market-ready active suspension systems is the limiting factor in the competition with semi-active devices. The variable geometry active suspension is an alternative with a significantly lower power consumption. However, previous designs suffer from packaging problems,

  7. Structural observation of long-span suspension bridges for safety assessment: implementation of an optical displacement measurement system

    International Nuclear Information System (INIS)

    Martins, L Lages; Ribeiro, A Silva; Rebordão, J M

    2015-01-01

    This paper addresses the implementation of an optical displacement measurement system in the observation scenario of a long-span suspension bridge and its contribution for structural safety assessment. The metrological background required for quality assurance of the measurements is described, namely, the system's intrinsic parameterization and integration in the SI dimensional traceability chain by calibration, including its measurement uncertainty assessment

  8. Reliable fuzzy H∞ control for active suspension of in-wheel motor driven electric vehicles with dynamic damping

    Science.gov (United States)

    Shao, Xinxin; Naghdy, Fazel; Du, Haiping

    2017-03-01

    A fault-tolerant fuzzy H∞ control design approach for active suspension of in-wheel motor driven electric vehicles in the presence of sprung mass variation, actuator faults and control input constraints is proposed. The controller is designed based on the quarter-car active suspension model with a dynamic-damping-in-wheel-motor-driven-system, in which the suspended motor is operated as a dynamic absorber. The Takagi-Sugeno (T-S) fuzzy model is used to model this suspension with possible sprung mass variation. The parallel-distributed compensation (PDC) scheme is deployed to derive a fault-tolerant fuzzy controller for the T-S fuzzy suspension model. In order to reduce the motor wear caused by the dynamic force transmitted to the in-wheel motor, the dynamic force is taken as an additional controlled output besides the traditional optimization objectives such as sprung mass acceleration, suspension deflection and actuator saturation. The H∞ performance of the proposed controller is derived as linear matrix inequalities (LMIs) comprising three equality constraints which are solved efficiently by means of MATLAB LMI Toolbox. The proposed controller is applied to an electric vehicle suspension and its effectiveness is demonstrated through computer simulation.

  9. Absorption Spectra of Gold Nanoparticle Suspensions

    Science.gov (United States)

    Anan'eva, M. V.; Nurmukhametov, D. R.; Zverev, A. S.; Nelyubina, N. V.; Zvekov, A. A.; Russakov, D. M.; Kalenskii, A. V.; Eremenko, A. N.

    2018-02-01

    Three gold nanoparticle suspensions are obtained, and mean radii in distributions - (6.1 ± 0.2), (11.9 ± 0.3), and (17.3 ± 0.7) nm - are determined by the transmission electron microscopy method. The optical absorption spectra of suspensions are obtained and studied. Calculation of spectral dependences of the absorption index of suspensions at values of the gold complex refractive index taken from the literature showed a significant deviation of experimental and calculated data in the region of 450-800 nm. Spectral dependences of the absorption of suspensions are simulated within the framework of the Mie-Drude theory taking into account the interband absorption in the form of an additional term in the imaginary part of the dielectric permittivity of the Gaussian type. It is shown that to quantify the spectral dependences in the region of the plasmon absorption band of nanoparticles, correction of the parameters of the interband absorption is necessary in addition to the increase of the relaxation parameter of the Drude theory. Spectral dependences of the dielectric permittivity of gold in nanodimensional state are refined from the solution of the inverse problem. The results of the present work are important for predicting the special features of operation of photonic devices and optical detonators based on gold nanoparticles.

  10. Controllable damping of high-Q violin modes in fused silica suspension fibers

    Science.gov (United States)

    Dmitriev, A. V.; Mescheriakov, S. D.; Tokmakov, K. V.; Mitrofanov, V. P.

    2010-01-01

    Fused silica fiber suspension of the test masses will be used in the interferometric gravitational wave detectors of the next generation. This allows a significant reduction of losses in the suspension and thermal noise associated with the suspension. Unfortunately, unwanted violin modes may be accidentally excited in the suspension fibers. The Q-factor of the violin modes also exceeds 108. They have a ring-down time that is too long and may complicate the stable control of the interferometer. Results of the investigation of a violin mode active damping system are described. An original sensor and actuator were especially developed to realize the effective coupling of a thin, optically transparent, non-conducting fused silica fiber with an electric circuit. The damping system allowed the changing of the violin mode's damping rate over a wide range.

  11. Chain Dynamics in Magnetorheological Suspensions

    Science.gov (United States)

    Gast, A. P.; Furst, E. M.

    1999-01-01

    Magnetorheological (MR) suspensions are composed of colloidal particles which acquire dipole moments when subjected to an external magnetic field. At sufficient field strengths and concentrations, the dipolar particles rapidly aggregate to form long chains. Subsequent lateral cross-linking of the dipolar chains is responsible for a rapid liquid-to-solid-like rheological transition. The unique, magnetically-activated rheological properties of MR suspensions make them ideal for interfacing mechanical systems to electronic controls. Additionally, the ability to experimentally probe colloidal suspensions interacting through tunable anisotropic potentials is of fundamental interest. Our current experimental work has focused on understanding the fluctuations of dipolar chains. It has been proposed by Halsey and Toor (HT) that the strong Landau-Peierls thermal fluctuations of dipolar chains could be responsible for long-range attractions between chains. Such interactions will govern the long-time relaxation of MR suspensions. We have synthesized monodisperse neutrally buoyant MR suspensions by density matching stabilized ferrofluid emulsion droplets with D2O. This allows us to probe the dynamics of the dipolar chains using light scattering without gravitational, interfacial, and polydispersity effects to resolve the short-wavelength dynamics of the dipolar chains. We used diffusing wave spectroscopy to measure these dynamics. The particle displacements at short times that show an independence to the field strength, but at long times exhibit a constrained, sub-diffusive motion that slows as the dipole strength is increased. The experiments are in good qualitative agreement with Brownian dynamics simulations of dipolar chains. Although there have been several important and detailed studies of the structure and interactions in MR suspensions, there has not been conclusive evidence that supports or contradicts the HT model prediction that long-range interactions exist between

  12. Preliminary investigations of design philosophies and features applicable to large magnetic suspension and balance systems

    Science.gov (United States)

    Britcher, C. P.; Fortescue, P. W.; Allcock, G. A.; Goodyer, M. J.

    1979-01-01

    The technology which is required to allow the principles of magnetic suspension and balance systems (MSBS) to be applied to the high Reynolds number transonic testing of aircraft models is examined. A test facility is presented as comprising a pressurized transonic cryogenic wind tunnel, with the MSBS providing full six degree of freedom control. The electro-magnets which are superconducting and fed from quiet, bipolar power supplies are examined. A model control system having some self adaptive characteristics is discussed.

  13. On issue of increasing profitability of automated energy technology complexes for preparation and combustion of water-coal suspensions

    Science.gov (United States)

    Brylina, O. G.; Osintsev, K. V.; Prikhodko, YU S.; Savosteenko, N. V.

    2018-03-01

    The article considers the issues of energy technological complexes economy increase on the existing techniques of water-coal suspensions preparation and burning basis due to application of highly effective control systems of electric drives and neurocontrol. The automated control system structure for the main boiler components is given. The electric drive structure is disclosed by the example of pumps (for transfer of coal-water mash and / or suspension). A system for controlling and diagnosing a heat and power complex based on a multi-zone regulator is proposed. The possibility of using neural networks for implementing the control algorithms outlined in the article is considered.

  14. Analysis of vibroprotection characteristics of pneumatic relaxation seat suspension with capability of vibration energy recuperation

    Directory of Open Access Journals (Sweden)

    Lyashenko Mikhail

    2017-01-01

    Full Text Available This paper proposes mechanism and control algorithm for pneumatic relaxation system of suspension with vibration energy recuperation applied to standard vehicle operator seat (“Sibeko” company. Mathematical model of the seat pneumatic relaxation suspension with two additional air volumes was created. Pneumatic motor – recuperator activated by means of air flow from the one additional volume to another is installed in air piping between additional volumes. Computational research was made in Matlab/Simulink. Amplitude-frequency characteristics of transmission coefficient for standard and proposed suspensions were plotted for preliminary evaluation of vibration protection properties of seat suspension. Performed comparative analysis of amplitude-frequency characteristics shows that noticeable improvement of vibration protection properties of pneumatic relaxation suspension system with vibration energy recuperation in comparison with standard system both in region of resonance disturbances and in above-resonance region. Main ways for further improvement of vibration protection properties of proposed system were marked out.

  15. Rheological and thermal properties of suspensions of microcapsules containing phase change materials.

    Science.gov (United States)

    Cao, Vinh Duy; Salas-Bringas, Carlos; Schüller, Reidar Barfod; Szczotok, Anna M; Hiorth, Marianne; Carmona, Manuel; Rodriguez, Juan F; Kjøniksen, Anna-Lena

    2018-01-01

    The thermal and rheological properties of suspensions of microencapsulated phase change materials (MPCM) in glycerol were investigated. When the microcapsule concentration is raised, the heat storage capacity of the suspensions becomes higher and a slight decline in the thermal conductivity of the suspensions is observed. The temperature-dependent shear-thinning behaviour of the suspensions was found to be strongly affected by non-encapsulated phase change materials (PCM). Accordingly, the rheological properties of the MPCM suspensions could be described by the Cross model below the PCM melting point while a power law model best described the data above the PCM melting point. The MPCM suspensions are interesting for energy storage and heat transfer applications. However, the non-encapsulated PCM contributes to the agglomeration of the microcapsules, which can lead to higher pumping consumption and clogging of piping systems.

  16. Roll and pitch independently tuned interconnected suspension: modelling and dynamic analysis

    Science.gov (United States)

    Xu, Guangzhong; Zhang, Nong; Roser, Holger M.

    2015-12-01

    In this paper, a roll and pitch independently tuned hydraulically interconnected passive suspension is presented. Due to decoupling of vibration modes and the improved lateral and longitudinal stability, the stiffness of individual suspension spring can be reduced for improving ride comfort and road grip. A generalised 14 degree-of-freedom nonlinear vehicle model with anti-roll bars is established to investigate the vehicle ride and handling dynamic responses. The nonlinear fluidic model of the hydraulically interconnected suspension is developed and integrated with the full vehicle model to investigate the anti-roll and anti-pitch characteristics. Time domain analysis of the vehicle model with the proposed suspension is conducted under different road excitations and steering/braking manoeuvres. The dynamic responses are compared with conventional suspensions to demonstrate the potential of enhanced ride and handling performance. The results illustrate the model-decoupling property of the hydraulically interconnected system. The anti-roll and anti-pitch performance could be tuned independently by the interconnected systems. With the improved anti-roll and anti-pitch characteristics, the bounce stiffness and ride damping can be optimised for better ride comfort and tyre grip.

  17. A simple route to prepare stable hydroxyapatite nanoparticles suspension

    International Nuclear Information System (INIS)

    Han Yingchao; Wang Xinyu; Li Shipu

    2009-01-01

    A simple ultrasound assisted precipitation method with addition of glycosaminoglycans (GAGs) is proposed to prepare stable hydroxyapatite (HAP) nanoparticles suspension from the mixture of Ca(H 2 PO 4 ) 2 solution and Ca(OH) 2 solution. The product was characterized by XRD, FT-IR, TEM, HRTEM and particle size, and zeta potential analyzer. TEM observation shows that the suspension is composed of 10-20 nm x 20-50 nm short rod-like and 10-30 nm similar spherical HAP nanoparticles. The number-averaged particle size of stable suspension is about 30 nm between 11.6 and 110.5 nm and the zeta potential is -60.9 mV. The increase of stability of HAP nanoparticles suspension mainly depends on the electrostatic effect and steric effect of GAGs. The HAP nanoparticles can be easily transported into the cancer cells and exhibit good potential as gene or drug carrier system.

  18. Controllable damping of high-Q violin modes in fused silica suspension fibers

    Energy Technology Data Exchange (ETDEWEB)

    Dmitriev, A V; Mescheriakov, S D; Mitrofanov, V P [Faculty of Physics, Moscow State University, Moscow 119991 (Russian Federation); Tokmakov, K V, E-mail: dmitriev@hbar.phys.msu.r, E-mail: mitr@hbar.phys.msu.r [Present address: Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

    2010-01-21

    Fused silica fiber suspension of the test masses will be used in the interferometric gravitational wave detectors of the next generation. This allows a significant reduction of losses in the suspension and thermal noise associated with the suspension. Unfortunately, unwanted violin modes may be accidentally excited in the suspension fibers. The Q-factor of the violin modes also exceeds 10{sup 8}. They have a ring-down time that is too long and may complicate the stable control of the interferometer. Results of the investigation of a violin mode active damping system are described. An original sensor and actuator were especially developed to realize the effective coupling of a thin, optically transparent, non-conducting fused silica fiber with an electric circuit. The damping system allowed the changing of the violin mode's damping rate over a wide range.

  19. Controllable damping of high-Q violin modes in fused silica suspension fibers

    International Nuclear Information System (INIS)

    Dmitriev, A V; Mescheriakov, S D; Mitrofanov, V P; Tokmakov, K V

    2010-01-01

    Fused silica fiber suspension of the test masses will be used in the interferometric gravitational wave detectors of the next generation. This allows a significant reduction of losses in the suspension and thermal noise associated with the suspension. Unfortunately, unwanted violin modes may be accidentally excited in the suspension fibers. The Q-factor of the violin modes also exceeds 10 8 . They have a ring-down time that is too long and may complicate the stable control of the interferometer. Results of the investigation of a violin mode active damping system are described. An original sensor and actuator were especially developed to realize the effective coupling of a thin, optically transparent, non-conducting fused silica fiber with an electric circuit. The damping system allowed the changing of the violin mode's damping rate over a wide range.

  20. Based on Artificial Neural Network to Realize K-Parameter Analysis of Vehicle Air Spring System

    Science.gov (United States)

    Hung, San-Shan; Hsu, Chia-Ning; Hwang, Chang-Chou; Chen, Wen-Jan

    2017-10-01

    In recent years, because of the air-spring control technique is more mature, that air- spring suspension systems already can be used to replace the classical vehicle suspension system. Depend on internal pressure variation of the air-spring, thestiffnessand the damping factor can be adjusted. Because of air-spring has highly nonlinear characteristic, therefore it isn’t easy to construct the classical controller to control the air-spring effectively. The paper based on Artificial Neural Network to propose a feasible control strategy. By using offline way for the neural network design and learning to the air-spring in different initial pressures and different loads, offline method through, predict air-spring stiffness parameter to establish a model. Finally, through adjusting air-spring internal pressure to change the K-parameter of the air-spring, realize the well dynamic control performance of air-spring suspension.

  1. Modelling nonlinear viscoelastic behaviours of loudspeaker suspensions-like structures

    Science.gov (United States)

    Maillou, Balbine; Lotton, Pierrick; Novak, Antonin; Simon, Laurent

    2018-03-01

    Mechanical properties of an electrodynamic loudspeaker are mainly determined by its suspensions (surround and spider) that behave nonlinearly and typically exhibit frequency dependent viscoelastic properties such as creep effect. The paper aims at characterizing the mechanical behaviour of electrodynamic loudspeaker suspensions at low frequencies using nonlinear identification techniques developed in recent years. A Generalized Hammerstein based model can take into account both frequency dependency and nonlinear properties. As shown in the paper, the model generalizes existing nonlinear or viscoelastic models commonly used for loudspeaker modelling. It is further experimentally shown that a possible input-dependent law may play a key role in suspension characterization.

  2. One-Quarter-Car Active SuspensionModel Verification

    Directory of Open Access Journals (Sweden)

    Hyniova Katerina

    2017-01-01

    Full Text Available Suspension system influences both the comfort and safety of the passengers. In the paper, energy recuperation and management in automotive suspension systems with linear electric motors that are controlled by a designed H∞ controller to generate a variable mechanical force for a car damper is presented. Vehicle shock absorbers in which forces are generated in response to feedback signals by active elements obviously offer increased design flexibility compared to the conventional suspensions with passive elements (springs and dampers. The main advantage of the proposed solution that uses a linear AC motor is the possibility to generate desired forces acting between the unsprung (wheel and sprung (one-quarter of the car body mass masses of the car, providing good insulation of the car sprung mass from the road surface roughness and load disturbances. As shown in the paper, under certain circumstances linear motors as actuators enable to transform mechanical energy of the vertical car vibrations to electrical energy, accumulate it, and use it when needed. Energy flow control enables to reduce or even eliminate the demands on the external power source. In particular, the paper is focused on experiments with active shock absorber that has been taken on the designed test bed and the way we developed an appropriate input signal for the test bed that as real road disturbance acts upon the vibration absorber and the obtained results are evaluated at the end. Another important point the active suspension design should satisfy is energy supply control that is made via standard controller modification, and which allows changing amount of energy required by the system. Functionality of the designed controller modification was verified taking various experiments on the experiment stand as mentioned in the paper.

  3. Free-Suspension Residual Flexibility Testing of Space Station Pathfinder: Comparison to Fixed-Base Results

    Science.gov (United States)

    Tinker, Michael L.

    1998-01-01

    Application of the free-suspension residual flexibility modal test method to the International Space Station Pathfinder structure is described. The Pathfinder, a large structure of the general size and weight of Space Station module elements, was also tested in a large fixed-base fixture to simulate Shuttle Orbiter payload constraints. After correlation of the Pathfinder finite element model to residual flexibility test data, the model was coupled to a fixture model, and constrained modes and frequencies were compared to fixed-base test. modes. The residual flexibility model compared very favorably to results of the fixed-base test. This is the first known direct comparison of free-suspension residual flexibility and fixed-base test results for a large structure. The model correlation approach used by the author for residual flexibility data is presented. Frequency response functions (FRF) for the regions of the structure that interface with the environment (a test fixture or another structure) are shown to be the primary tools for model correlation that distinguish or characterize the residual flexibility approach. A number of critical issues related to use of the structure interface FRF for correlating the model are then identified and discussed, including (1) the requirement of prominent stiffness lines, (2) overcoming problems with measurement noise which makes the antiresonances or minima in the functions difficult to identify, and (3) the use of interface stiffness and lumped mass perturbations to bring the analytical responses into agreement with test data. It is shown that good comparison of analytical-to-experimental FRF is the key to obtaining good agreement of the residual flexibility values.

  4. Rheological and technological properties of zirconium suspensions stabilized with various amounts of calcium oxide

    International Nuclear Information System (INIS)

    Shulik, I.G.; Usatikov, I.F.; Alekseenko, A.S.

    1987-01-01

    A complex research of properties of zirconium dioxide-based suspensions with various amounts of calcium oxide up to calcium zirconate is carried out. Aqueous suspensions are used when preparing a complex form of ZrO 2 -based ceramics by the method of slip casting. Phase composition effect on the nature of rheologic curves ie found. The role of organic alcohol additions in the improvement of suspension flowability and reduction of casting porosity is noted

  5. Asystole following Reintubation during Suspension Laryngoscopy

    Directory of Open Access Journals (Sweden)

    Sheryl H. Glassman

    2012-01-01

    Full Text Available Transient increase in heart rate and mean arterial pressure commonly occur during manipulation of the airway via direct laryngoscopy. This phenomenon is understood to be due to a sympathetic nervous system reflex causing an increase in plasma catecholamines. Rarely, severe bradycardia and possible asystole can occur following laryngoscopy. One previous report described asystole during suspension laryngoscopy after uneventful direct laryngoscopy. Here we report a case of asystole occurring at the time of reinsertion and cuff inflation of an endotracheal tube in a patient who had been hemodynamically stable during initial direct laryngoscopy and the ensuing suspension laryngoscopy. The asystole was immediately recognized and successful cardiopulmonary resuscitation was performed with the patient returning to baseline sinus rhythm. Cardiac arrest following laryngoscopy is rare. This case highlights the importance of continued vigilance even after the initial manipulations of the airway by both direct laryngoscopy and suspension laryngoscopy are to be performed. Identifying patients who may benefit from premedication with a vagolytic drug may prevent adversity. Preoperative heart rate analysis can identify patients with strong vagal tone.

  6. Evaluating Suspension Formulations of Theophylline Cocrystals With Artificial Sweeteners.

    Science.gov (United States)

    Aitipamula, Srinivasulu; Wong, Annie B H; Kanaujia, Parijat

    2018-02-01

    Pharmaceutical cocrystals have garnered significant interest as potential solids to address issues associated with formulation development of drug substances. However, studies concerning the understanding of formulation behavior of cocrystals are still at the nascent stage. We present results of our attempts to evaluate suspension formulations of cocrystals of an antiasthmatic drug, theophylline, with 2 artificial sweeteners. Stability, solubility, drug release, and taste of the suspension formulations were evaluated. Suspension that contained cocrystal with acesulfame showed higher drug release rate, while a cocrystal with saccharin showed a significant reduction in drug release rate. The cocrystal with saccharin was found stable in suspension for over 9 weeks at accelerated test condition; in contrast, the cocrystal with acesulfame was found unstable. Taste analysis using an electronic taste-sensing system revealed improved sweetness of the suspension formulations with cocrystals. Theophylline has a narrow therapeutic index with a short half-life which necessitates frequent dosing. This adversely impacts patient compliance and enhances risk of gastrointestinal and cardiovascular adverse effects. The greater thermodynamic stability, sweetness, and sustained drug release of the suspension formulation of theophylline-saccharin could offer an alternative solution to the short half-life of theophylline and make it a promising formulation for treating asthmatic pediatric and geriatric patients. Copyright © 2018 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  7. Glycyrrhiza glabra (Linn.) and Lavandula officinalis (L.) cell suspension cultures-based biotransformation of β-artemether.

    Science.gov (United States)

    Patel, Suman; Gaur, Rashmi; Upadhyaya, Mohita; Mathur, Archana; Mathur, Ajay K; Bhakuni, Rajendra S

    2011-07-01

    The biotransformation of β-artemether (1) by cell suspension cultures of Glycyrrhiza glabra and Lavandula officinalis is reported here for the first time. The major biotransformed product appeared as a grayish-blue color spot on thin-layer chromatography (TLC) with transparent crystal-like texture. Based on its infrared (IR) and (1)H nuclear magnetic resonance (NMR) spectra, the product was characterized as a tetrahydrofuran (THF)-acetate derivative (2). The highest conversion efficiencies of 57 and 60% were obtained when 8-9-day-old cell suspensions of G. glabra and L. officinalis were respectively fed with 4-7 mg of compound 1 in 40 ml of medium per culture and the cells were harvested after 2-5 days of incubation. The addition of compound 1 at the beginning of the culture cycle caused severe growth depression in a dose-dependent manner, resulting in poor bioconversion efficiency of ~25% at 2-5 mg/culture dose only.

  8. Energy Conservation Analysis and Control of Hybrid Active Semiactive Suspension with Three Regulating Damping Levels

    Directory of Open Access Journals (Sweden)

    Long Chen

    2016-01-01

    Full Text Available Active suspension has not been popularized for high energy consumption. To address this issue, this paper introduces the concept of a new kind of suspension. The linear motor is considered to be integrated into an adjustable shock absorber to form the hybrid active semiactive suspension (HASAS. To realize the superiority of HASAS, its energy consumption and regeneration mechanisms are revealed. And the system controller which is composed of linear quadratic regulator (LQR controller, mode decision and switch controller, and the sliding mode control based thrust controller is developed. LQR controller is designed to maintain the suspension control objectives, while mode decision and switch controller decides the optimal damping level to tune motor thrust. The thrust controller ensures motor thrust tracking. An adjustable shock absorber with three regulating levels to be used in HASAS is trial produced and tested to obtain its working characteristics. Finally, simulation analysis is made with the experimental three damping characteristics. The impacts of adjustable damping on the motor force and energy consumption are investigated. Simulation results demonstrate the advantages of HASAS in energy conservation with various suspension control objectives. Even self-powered active control and energy regenerated to the power source can be realized.

  9. Simple additive manufacturing of an osteoconductive ceramic using suspension melt extrusion

    DEFF Research Database (Denmark)

    Slots, Casper; Bonde Jensen, Martin; Ditzel, Nicholas

    2017-01-01

    /calcium phosphate suspension melt for simple additive manufacturing of ceramic tricalcium phosphate implants. METHODS: A wide variety of non-aqueous liquids were tested to determine the formulation of a storable 3D printable tricalcium phosphate suspension ink, and only fatty acid-based inks were found to work...

  10. Compressed Air Production Using Vehicle Suspension

    Directory of Open Access Journals (Sweden)

    Ninad Arun Malpure

    2015-08-01

    Full Text Available Abstract Generally compressed air is produced using different types of air compressors which consumes lot of electric energy and is noisy. In this paper an innovative idea is put forth for production of compressed air using movement of vehicle suspension which normal is wasted. The conversion of the force energy into the compressed air is carried out by the mechanism which consists of the vehicle suspension system hydraulic cylinder Non-return valve air compressor and air receiver. We are collecting air in the cylinder and store this energy into the tank by simply driving the vehicle. This method is non-conventional as no fuel input is required and is least polluting.

  11. Stability of an extemporaneously compounded minoxidil oral suspension.

    Science.gov (United States)

    Song, Yunmei; Chin, Zen Whey; Ellis, David; Lwin, Ei Mon Phyo; Turner, Sean; Williams, Desmond; Garg, Sanjay

    2018-03-01

    Results of a study to determine the stability of an extemporaneously compounded minoxidil oral suspension under various temperature and stress conditions are reported. Commercially available minoxidil tablets (10 mg) were crushed to a fine powder, and predetermined amounts of 2 suspending vehicles were added to produce a 1-mg/mL suspension, which was stored in glass bottles at room temperature (25 ± 2 °C) or in a refrigerator (4 ± 2 °C). To simulate daily patient use, 5 days weekly 1 bottle of the suspension was removed from refrigerated storage and shaken and 0.5 mL of the contents discarded. At each specified time point, samples were analyzed in duplicate ( n = 6 for each test condition) using a validated high-performance liquid chromatography method. Samples were visually observed and their pH measured at each time point. Microbiological studies were performed on day 0 and at week 24. The mean percentage of initial minoxidil concentration remaining in all refrigerated samples exceeded 90% throughout the 24-week study, with no change in appearance, pH, microbial activity, odor, or redispersibility. During storage at room temperature, the suspension exhibited a color change at week 4, with slight sedimentation after 6 weeks, although minoxidil recovery exceeded 90% for 10 weeks. An extemporaneously compounded minoxidil oral suspension was stable for 24 weeks when stored in a refrigerator. This suspension can be used for up to 3 weeks when stored at room temperature. Copyright © 2018 by the American Society of Health-System Pharmacists, Inc. All rights reserved.

  12. Magneto-rheological suspensions for improving ground vehicle's ride comfort, stability, and handling

    Science.gov (United States)

    Ahmadian, Mehdi

    2017-10-01

    A state-of-the-art discussion on the applications of magneto-rheological (MR) suspensions for improving ride comfort, handling, and stability in ground vehicles is discussed for both road and rail applications. A historical perspective on the discovery and engineering development of MR fluids is presented, followed by some of the common methods for modelling their non-Newtonian behaviour. The common modes of the MR fluids are discussed, along with the application of the fluid in valve mode for ground vehicles' dampers (or shock absorbers). The applications span across nearly all road vehicles, including automobiles, trains, semi-trucks, motorcycles, and even bicycles. For each type of vehicle, the results of some of the past studies is presented briefly, with reference to the originating study. It is discussed that Past experimental and modelling studies have indicated that MR suspensions provide clear advantages for ground vehicles that far surpasses the performance of passive suspension. For rail vehicles, the primary advantage is in terms of increasing the speed at which the onset of hunting occurs, whereas for road vehicles - mainly automobiles - the performance improvements are in terms of a better balance between vehicle ride, handling, and stability. To further elaborate on this point, a single-suspension model is used to develop an index-based approach for studying the compromise that is offered by vehicle suspensions, using the H2 optimisation approach. Evaluating three indices based on the sprung-mass acceleration, suspension rattlespace, and tyre deflection, it is clearly demonstrated that MR suspensions significantly improve road vehicle's ride comfort, stability, and handling in comparison with passive suspensions. For rail vehicles, the simulation results indicate that using MR suspensions with an on-off switching control can increase the speed at which the on-set of hunting occurs by as much as 50% to more than 300%.

  13. Physical gelation of a microfiber suspension.

    Science.gov (United States)

    Perazzo, Antonio; Nunes, Janine K.; Guido, Stefano; Stone, Howard A.

    2015-11-01

    Hydrogels are among the most exploited materials in tissue engineering and there is growing interest in injectable hydrogels, especially as applied to surgical adhesives and bioprinting materials. Here we report a method to produce a hydrogel in a desired location by simply extruding a suspension of high aspect ratio and flexible microfibers from a syringe. The mechanism of gel formation is purely physical and based on irreversible entanglements formed by the microfibers under the action of flow. The single microfibers have been produced and finely tailored by microfluidic methods. Shear rheology has been performed in order to get insights on the entanglements, and results show that the formation of entanglements is related to a shear thickening behavior of the suspension, which in turn depends on shear rate and concentration of fibers. When shearing the suspension, highly non-linear viscoelastic behavior is observed and probed by a highly positive first normal stress difference. We also report the hydrogel swelling behavior and its linear viscoelastic properties as obtained by imposing small oscillatory stress to the material.

  14. 31 CFR 357.30 - Cases of delay or suspension of payment.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false Cases of delay or suspension of payment. 357.30 Section 357.30 Money and Finance: Treasury Regulations Relating to Money and Finance... Securities System (Legacy Treasury Direct) § 357.30 Cases of delay or suspension of payment. If evidence...

  15. Long-time behavior for suspension bridge equations with time delay

    Science.gov (United States)

    Park, Sun-Hye

    2018-04-01

    In this paper, we consider suspension bridge equations with time delay of the form u_{tt}(x,t) + Δ ^2 u (x,t) + k u^+ (x,t) + a_0 u_t (x,t) + a_1 u_t (x, t- τ ) + f(u(x,t)) = g(x). Many researchers have studied well-posedness, decay rates of energy, and existence of attractors for suspension bridge equations without delay effects. But, as far as we know, there is no work about suspension equations with time delay. In addition, there are not many studies on attractors for other delayed systems. Thus we first provide well-posedness for suspension equations with time delay. And then show the existence of global attractors and the finite dimensionality of the attractors by establishing energy functionals which are related to the norm of the phase space to our problem.

  16. Controlling active cabin suspensions in commercial vehicles

    NARCIS (Netherlands)

    Evers, W.J.E.; Besselink, I.J.M.; Teerhuis, A.P.; Knaap, van der A.C.M.; Nijmeijer, H.

    2009-01-01

    The field of automotive suspensions is changing. Semi-active and active suspensions are starting to become viable options for vehicle designers. Suspension design for commercial vehicles is especially interesting given its potential. An active cabin suspension for a heavy-duty truck is considered,

  17. Suspensions with reduced violin string modes

    International Nuclear Information System (INIS)

    Lee, B H; Ju, L; Blair, D G

    2006-01-01

    We discuss the possibility of significantly reducing the number and Q-factor of violin string modes in the mirror suspension. Simulations of a bar-flexure suspension and an orthogonal ribbon have shown a reduction in the number of violin string modes when compared to a normal ribbon suspension. By calculating the expected suspension thermal noise, we find that the orthogonal ribbon provides a promising suspension alternative. A lower number of violin modes oscillating in the direction of the laser and a reduction in violin mode peak values of at least 23dB can be achieved with a slight increase in thermal noise above 40Hz

  18. Suspensions with reduced violin string modes

    Energy Technology Data Exchange (ETDEWEB)

    Lee, B H; Ju, L; Blair, D G [School of Physics, University of Western Australia, Crawley 6009, WA (Australia)

    2006-03-02

    We discuss the possibility of significantly reducing the number and Q-factor of violin string modes in the mirror suspension. Simulations of a bar-flexure suspension and an orthogonal ribbon have shown a reduction in the number of violin string modes when compared to a normal ribbon suspension. By calculating the expected suspension thermal noise, we find that the orthogonal ribbon provides a promising suspension alternative. A lower number of violin modes oscillating in the direction of the laser and a reduction in violin mode peak values of at least 23dB can be achieved with a slight increase in thermal noise above 40Hz.

  19. Suspension Hydrogen Reduction of Iron Oxide Concentrates

    Energy Technology Data Exchange (ETDEWEB)

    H.Y. Sohn

    2008-03-31

    The objective of the project is to develop a new ironmaking technology based on hydrogen and fine iron oxide concentrates in a suspension reduction process. The ultimate objective of the new technology is to replace the blast furnace and to drastically reduce CO2 emissions in the steel industry. The goals of this phase of development are; the performance of detailed material and energy balances, thermochemical and equilibrium calculations for sulfur and phosphorus impurities, the determination of the complete kinetics of hydrogen reduction and bench-scale testing of the suspension reduction process using a large laboratory flash reactor.

  20. Rotational magnetic pulses enhance the magnetofection efficiency in vitro in adherent and suspension cells

    International Nuclear Information System (INIS)

    Dahmani, Ch.; Mykhaylyk, O.; Helling, Fl.; Götz, St.; Weyh, Th.; Herzog, H.-G.; Plank, Ch.

    2013-01-01

    The association of magnetic nanoparticles with gene delivery vectors in combination with the use of gradient magnetic fields (magnetofection) enables improved and synchronised gene delivery to cells. In this paper, we report a system comprising rotating permanent magnets to generate defined magnetic field pulses with frequencies from 2.66 to 133 Hz and a field amplitude of 190 or 310 mT at the location of the cells. Low-frequency pulses of 2.66–10 Hz with a magnetic flux density of 190 mT were applied to the examined cells for 30–120 s after magnetofection. These pulses resulted in a 1.5–1.9-fold enhancement in the transfection efficiency compared with magnetofection with only a static magnetic field in both adherent and suspension cells. The magnetic field amplitudes of 190 and 310 mT had similar effects on the transfection efficacy. No increase in the percentage of transgene-expressing suspension cells and no cytotoxic effects (based on the results of the MTT assay) were observed after applying alternating magnetic fields. - Highlights: ► We developed a magnetic system capable of generating defined magnetic pulses based on permanent magnets. ► The main advantage of the system is the lack of heat-induced fluctuations in the working parameters. ► Our system succeeded in enhancing the transfection of adherent human lung epithelial cells and human suspension cells. ► The enhancement in the transfection efficiency compared with static magnetic field is due to the magnetic field pulses. ► The approach could be used as a complementary method for drug targeting

  1. The behaviour of a vehicle’s suspension system on dynamic testing conditions

    Science.gov (United States)

    Mihon, L.; Lontiş, N.; Deac, S.

    2018-01-01

    The paper presents a car suspension’s behaviour on dynamic testing conditions through theoretical and mathematical simulation on specific model, on the single traction wheel, according to the real vehicle and by experiment on the test bench by reproducing the road’s geometry and vehicle’s speed and measuring the acceleration and damping response of the suspension system on that wheel. There are taking in consideration also the geometry and properties of the tyre-wheel model and physical wheel’s properties. The results are important due to the suspension’s model properties which allows to extend the theory and applications to the whole vehicle for improving the vehicle’s dynamics.

  2. Effect of suspension characteristics on in-flight particle properties and coating microstructures achieved by suspension plasma spray

    Science.gov (United States)

    Aubignat, E.; Planche, M. P.; Allimant, A.; Billières, D.; Girardot, L.; Bailly, Y.; Montavon, G.

    2014-11-01

    This paper focuses on the influence of suspension properties on the manufacturing of coatings by suspension plasma spraying (SPS). For this purpose, alumina suspensions were formulated with two different liquid phases: water and ethanol. Suspensions were atomized with a twin-fluid nozzle and injected in an atmospheric plasma jet. Suspension injection was optimized thanks to shadowgraphy observations and drop size distribution measurements performed by laser diffraction. In-flight particle velocities were evaluated by particle image velocimetry. In addition, splats were collected on glass substrates, with the same conditions as the ones used during the spray process. Scanning electron microscopy (SEM) and profilometry analyses were then performed to observe the splat morphology and thus to get information on plasma / suspension interactions, such as particle agglomeration. Finally, coatings were manufactured, characterized by SEM and compared to each other.

  3. Preview control of vehicle suspension system featuring MR shock absorber

    Energy Technology Data Exchange (ETDEWEB)

    Seong, M S; Choi, S B [Smart Structures and Systems Laboratory, Department of Mechanical Engineering, Inha University, Incheon 402-751 (Korea, Republic of); Cho, M W [Precision Manufacturing and Inspection Laboratory, Department of Mechanical Engineering, Inha University, Incheon 402-751 (Korea, Republic of); Lee, H G [Department of Automotive Engineering, Daeduk College, Daejeon, 305-715 (Korea, Republic of)], E-mail: seungbok@inha.ac.kr

    2009-02-01

    This paper presents control performance evaluation of optimal preview control algorithm for vehicle suspension featuring MR shock absorber. The optimal preview control algorithm has several advantages such as high control performance over that which is best for a non-preview system. In order to achieve this goal, a commercial MR shock absorber, Delphi MganerideTM, which is applicable to high class passenger vehicle, is adopted and its field-dependent damping force and dynamic responses are experimentally evaluated. Then the governing equation of motion for the full-vehicle model is established and integrated with the MR shock absorber. Subsequently, optimal controller with preview control algorithm is formulated and implemented for vibration suppression of the car body. Control performance of the preview controller is evaluated for the full-vehicle model under random road condition. In addition, the control performances depending on preview distances are evaluated.

  4. Preview control of vehicle suspension system featuring MR shock absorber

    International Nuclear Information System (INIS)

    Seong, M S; Choi, S B; Cho, M W; Lee, H G

    2009-01-01

    This paper presents control performance evaluation of optimal preview control algorithm for vehicle suspension featuring MR shock absorber. The optimal preview control algorithm has several advantages such as high control performance over that which is best for a non-preview system. In order to achieve this goal, a commercial MR shock absorber, Delphi MganerideTM, which is applicable to high class passenger vehicle, is adopted and its field-dependent damping force and dynamic responses are experimentally evaluated. Then the governing equation of motion for the full-vehicle model is established and integrated with the MR shock absorber. Subsequently, optimal controller with preview control algorithm is formulated and implemented for vibration suppression of the car body. Control performance of the preview controller is evaluated for the full-vehicle model under random road condition. In addition, the control performances depending on preview distances are evaluated.

  5. Improving Performance of Cantilevered Momentum Wheel Assemblies by Soft Suspension Support

    Directory of Open Access Journals (Sweden)

    Weiyong Zhou

    2013-01-01

    Full Text Available This paper focuses on improving the performance of the rigid support cantilevered momentum wheel assemblies (CMWA by soft suspension support. A CMWA, supported by two angular contact ball bearings, was modeled as a Jeffcott rotor. The support stiffness, before and after in series with a linear soft suspension support, were simplified as two Duffing's type springs respectively. The result shows that the rigid support CMWA produces large disturbance force at the resonance speed range. The soft suspension CMWA can effectively reduce the force on the bearing (also disturbance forces produced by the CMWA at high rotational speed, and also reduce the nonlinear characteristic of the stiffness. However, the instability of the soft suspension CMWA will limit the maximum rotational speed of the CMWA. Thus, a "proper" stiffness of the soft suspension system is a trade-off strategy between reduction of the force and extension of the speed range simultaneously.

  6. Investigation of Equivalent Unsprung Mass and Nonlinear Features of Electromagnetic Actuated Active Suspension

    Directory of Open Access Journals (Sweden)

    Jun Yin

    2015-01-01

    Full Text Available Electromagnetic actuated active suspension benefits active control and energy harvesting from vibration at the same time. However, the rotary type electromagnetic actuated active suspension introduces a significant extra mass on the unsprung mass due to the inertia of the rotating components of the actuator. The magnitude of the introduced unsprung mass is studied based on a gearbox type actuator and a ball screw type actuator. The geometry of the suspension and the actuator also influence the equivalent unsprung mass significantly. The suspension performance simulation or control logic derived should take this equivalent unsprung mass into account. Besides, an extra force should be compensated due to the nonlinear features of the suspension structure and it is studied. The active force of the actuator should compensate this extra force. The discovery of this paper provides a fundamental for evaluating the rotary type electromagnetic actuated active suspension performance and control strategy derived as well as controlling the electromagnetic actuated active suspension more precisely.

  7. Determination of adsorbed protein concentration in aluminum hydroxide suspensions by near-infrared transmittance Spectroscopy

    DEFF Research Database (Denmark)

    Lai, Xuxin; Zheng, Yiwu; Jacobsen, Susanne

    2008-01-01

    , using the partial least square regression (PLSR) method to construct a calibration model. The linear concentration range of adsorbed BSA is from 0 to 1.75 mg/mL by using 10 mm path length cuvettes. The influence of the sedimentation in suspension, different buffers, and different aluminum hydroxide......Analysis of aluminum hydroxide based vaccines is difficult after antigen adsorption. Adsorbed protein is often assessed by measuring residual unadsorbed protein for quality control. A new method for the direct determination of adsorbed protein concentration in suspension using near-infrared (NIR......) transmittance spectroscopy is proposed here. A simple adsorption system using albumin from bovine serum (BSA) and aluminum hydroxide as a model system is employed. The results show that the NIR absorbance at 700-1300 nm is correlated to the adsorbed BSA concentration, measured by the ultraviolet (UV) method...

  8. An Active Seat Controller with Vehicle Suspension Feedforward and Feedback States: An Experimental Study

    Directory of Open Access Journals (Sweden)

    Abdulaziz Alfadhli

    2018-04-01

    Full Text Available Active seat suspensions can be used to reduce the harmful vertical vibration of a vehicle’s seat by applying an external force using a closed loop controller. Many of the controllers found in the literature are difficult to implement practically, because they are based on using unavailable or difficult and costly measurements. This paper presents both simulation and experimental studies of five novel, simple, and cost-effective control strategies to be used for an active seat suspension in order to improve ride comfort at low frequencies below 20 Hz. These strategies use available and measurable feedforward (preview information states from the vehicle secondary suspension, as well as feedback states from the seat suspension, together with gains optimised to minimise the occupant vibration. The gains were optimised using a genetic algorithm (GA, with a fitness function based on the seat effective amplitude transmissibility (SEAT factor. Constraints on the control force and the seat suspension stroke were also included in the optimisation algorithm. Simulation and laboratory experimental tests were carried out to assess the performance of the proposed controllers according to the ISO 2631-1 standard, in both the frequency and time domains with a range of different road profiles. The experimental tests were performed using a multi-axis simulation table (MAST and a physical active seat suspension configured as a hardware-in-loop (HIL simulation with a virtual linear quarter vehicle model (QvM. The results demonstrate that the proposed controllers substantially attenuate the vertical vibration at the driver’s seat compared with both a passive and a proportional-integral-derivative (PID active seat suspension and thus improve ride comfort together with reducing vibration-linked health risks. Moreover, experimental results show that employing both feedforward information and feedback vehicle body and seat acceleration signals in the controller

  9. Improving the cooling performance of electrical distribution transformer using transformer oil – Based MEPCM suspension

    OpenAIRE

    Mushtaq Ismael Hasan

    2017-01-01

    In this paper the electrical distribution transformer has been studied numerically and the effect of outside temperature on its cooling performance has been investigated. The temperature range studied covers the hot climate regions. 250 KVA distribution transformer is chosen as a study model. A novel cooling fluid is proposed to improve the cooling performance of this transformer, transformer oil-based microencapsulated phase change materials suspension is used with volume concentration (5–25...

  10. Osmotic consolidation of suspensions and gels

    International Nuclear Information System (INIS)

    Miller, K.T.; Zukoski, C.F.

    1994-01-01

    An osmotic method for the consolidation of suspensions of ceramic particles is demonstrated. Concentrated solutions of poly(ethylene oxide) are separated from a suspension of ceramic particles by a semipermeable membrane, creating a gradient in solvent chemical potential. Solvent passes from the suspension into the polymer solution, lowering its free energy and consolidating the suspension. Dispersions of stable 8-nm hydrous zirconia particles were consolidated to over 47% by volume. Suspensions of α-alumina in three states of aggregation (dispersed, weakly flocculated, and strongly flocculated) were consolidated to densities greater than or equal to those produced in conventional pressure filtration. Moreover, the as-consolidated alumina bodies were partially drained of fluid during the osmotic consolidation process, producing cohesive partially dried bodies with improved handling characteristics

  11. Comparison of techniques for the determination of conversion during suspension polymerization reactions

    Directory of Open Access Journals (Sweden)

    J. C. Santos

    2008-06-01

    Full Text Available The determination of conversion during suspension polymerization reactions is not an easy task due to the heterogeneity of the reaction medium and the tendency of particles to agglomerate rapidly when stirring is stopped. Usually, bulk polymerization in ampoules is employed to study the kinetics of suspension polymerization reactions. In this work, a comparison of different techniques for the determination of conversion during suspension polymerization reactions is presented. Results showed a good agreement between the conversion obtained by gravimetry during styrene suspension polymerization and on-line conversion monitoring data using fiber-optic based Raman Spectroscopy. Nevertheless, the polymerization rate of styrene bulk polymerization carried out in ampoules was higher than the real reaction rate of styrene suspension polymerization due to slightly higher reaction temperatures. Simulation results using the experimental temperature data in a mathematical model confirmed these results.

  12. Mixing and solid suspension in a stirred precipitator

    International Nuclear Information System (INIS)

    Chang, T.P.

    1986-04-01

    Full-scale mixing and solid suspension studies have been conducted to determine the optimum agitator design for precipitators used in plutonium processing. Design considerations include the geometry of precipitator vessels, feed locations, flow patterns, and product requirements. Evaluations of various agitator designs are based on their capabilities: (1) to achieve uniform mixing of reactants in minimum time, (2) to suspend slurry uniformly throughout the vessel, and (3) to minimize power consumption without inducing air entrainment. Tests of full-scale agitator designs showed that significant improvements in mixing, solid suspension, and energy consumption were achieved

  13. A prospective, randomized, controlled study of a suspension positioning system used with elderly bedridden patients with neurogenic fecal incontinence.

    Science.gov (United States)

    Su, Mei-Yin; Lin, Shi-Quan; zhou, Ye-Wen; Zhou, Ye-Wen; Liu, Si-Ya; Lin, Ai; Lin, Xi-Rong

    2015-01-01

    Elderly patients with acute neurological impairment are prone to severe disability, fecal incontinence (FI), and resultant complications. A suspension positioning system (SPS), based on the orthopedic suspension traction system commonly used for conservative treatment of pediatric femoral fracture and uncomplicated adult pelvic fracture, was developed to facilitate FI management in patients immobilized secondary to an acute neurological condition. To evaluate the effectiveness and safety of the system, a prospective, randomized, controlled study was conducted between October 2009 and July 2012. Two hundred (200) elderly, bedridden, hospitalized patients with acute, nonchronic neurological impairment were randomly assigned to receive routine FI nursing care (ie, individualized dietary modification, psychological support, health education, and social support for caregivers and family members [control group]) or routine incontinence care plus the SPS (experimental group) during the day. Rates of perianal fecal contamination, skin breakdown, incontinence associated dermatitis, pressure ulcer development, and lower urinary tract infection (LUTI) were significantly lower in the SPS than in the control group (P <0.05). Length of hospitalization and costs of care were also lower in the SPS group (P <0.05). Patient quality-of-life (QoL) and FI QoL scores were similar at baseline but significantly higher (better) at the 6-month follow-up interview in the SPS than in the control group (P <0.05). In this study, the rate of FI-associated morbidities was lower and 6-month patient QoL scores were higher in the SPS than in the control group. No adverse events were observed, and all patients completed the study. Further clinical studies are needed to examine the long-term effects of SPS use among neurologically impaired FI patients.

  14. On Determination of the Equation of State of Colloidal Suspensions

    Science.gov (United States)

    Sirorattanakul, Krittanon; Huang, Hao; Uhl, Christopher; Ou-Yang, Daniel

    Colloidal suspensions are the main ingredients for a variety of materials in our daily life, e.g., milk, salad dressing, skin lotions and paint for wall coatings. Material properties of these systems require an understanding of the equation of state of these materials. Our project aims to experimentally determine the equation of state of colloidal suspensions by microfluidics, dielectrophoresis (DEP) and optical imaging. We use fluorescent polystyrene latexes as a model system for this study. Placing semi-permeable membranes between microfluidics channels, which made from PDMS, we control the particle concentration and ionic strengths of the suspension. We use osmotic equilibrium equation to analyze the particle concentration distribution in a potential force field created by DEP. We use confocal optical imaging to measure the spatial distribution of the particle concentration. We compare the results of our experimental study with data obtained by computer simulation of osmotic equilibrium of interacting colloids. NSF DMR-0923299, Emulsion Polymer Institute, Department of Physics, Bioengineering Program of Lehigh University.

  15. Suspension Bridge Flutter for Girder with Separate Control Flaps

    DEFF Research Database (Denmark)

    Huynh, T.; Thoft-Christensen, Palle

    Active vibration control of long span suspension bridge flutter using separated control flaps (SFSC) has shown to increase effectively the critical wind speed of bridges. In this paper, an SFSC calculation based on modal equations of the vertical and torsional motions of the bridge girder including...... the flaps is presented. The length of the flaps attached to the girder, the flap configuration and the flap rotational angles are parameters used to increase the critical wind speed of the bridge. To illustrate the theory a numerical example is shown for a suspension bridge of 1000m+2500m+1000m span based...... on the Great Belt Bridge streamlined girder....

  16. Rheological properties of hydrate suspensions in asphaltenic crude oils; Proprietes rheologiques de suspensions d'hydrate dans des bruts asphalteniques

    Energy Technology Data Exchange (ETDEWEB)

    Marques de Toledo Camargo, R.

    2001-03-01

    The development of offshore oil exploitation under increasing water depths has forced oil companies to increase their understanding of gas hydrate formation and transportation in multiphase flow lines in which a liquid hydrocarbon phase is present. This work deals with the flow behaviour of hydrate suspensions in which a liquid hydrocarbon is the continuous phase. Three different liquid hydrocarbons are used: an asphaltenic crude oil, a condensate completely free of asphaltenes and a mixture between the asphaltenic oil and heptane. The rheological characterisation of hydrate suspensions is the main tool employed. Two original experimental devices are used: a PVT cell adapted to operate as a Couette type rheometer and a semi-industrial flow loop. Hydrate suspensions using the asphaltenic oil showed shear-thinning behaviour and thixotropy. This behaviour is typically found in flocculated systems, in which the particles attract each other forming flocs of aggregated particles at low shear rates. The suspensions using the condensate showed Newtonian behaviour. Their relative viscosities were high, which suggests that an aggregation process between hydrate particles takes. place during hydrate formation. Finally, hydrate suspensions using the mixture asphaltenic oil-heptane showed shear-thinning behaviour, thixotropy and high relative viscosity. From these results it can be inferred that, after the achievement of the hydrate formation process, the attractive forces between hydrate particles are weak. making unlikely pipeline obstruction by an aggregation process. Nevertheless, during the hydrate formation, these attractive forces can be sufficiently high. It seems that the hydrate surface wettability is an important parameter in this phenomena. (author)

  17. Dispersing and stabilizing effect of nonaqueous media with different acid-base functions when preparing process suspensions

    International Nuclear Information System (INIS)

    Koshevar, V.D.; Rat'ko, A.I.; Mironenko, I.N.

    1999-01-01

    Dispersing and stabilizing effect of organic liquids related to the Lewis acids and baser is studied when preparing the suspensions of certain minerals and metal oxides, beryllium oxide, in particular. Practical recommendations are provided for the choice of dispersing media to produce stable suspensions

  18. Large-scale photochemical reactions of nanocrystalline suspensions: a promising green chemistry method.

    Science.gov (United States)

    Veerman, Marcel; Resendiz, Marino J E; Garcia-Garibay, Miguel A

    2006-06-08

    Photochemical reactions in the solid state can be scaled up from a few milligrams to 10 grams by using colloidal suspensions of a photoactive molecular crystal prepared by the solvent shift method. Pure products are recovered by filtration, and the use of H(2)O as a suspension medium makes this method a very attractive one from a green chemistry perspective. Using the photodecarbonylation of dicumyl ketone (DCK) as a test system, we show that reaction efficiencies in colloidal suspensions rival those observed in solution. [reaction: see text

  19. Numerical homogenization on approach for stokesian suspensions.

    Energy Technology Data Exchange (ETDEWEB)

    Haines, B. M.; Berlyand, L. V.; Karpeev, D. A. (Mathematics and Computer Science); (Department of Mathematics, Pennsylvania State Univ.)

    2012-01-20

    In this technical report we investigate efficient methods for numerical simulation of active suspensions. The prototypical system is a suspension of swimming bacteria in a Newtonian fluid. Rheological and other macroscopic properties of such suspensions can differ dramatically from the same properties of the suspending fluid alone or of suspensions of similar but inactive particles. Elongated bacteria, such as E. coli or B. subtilis, swim along their principal axis, propelling themselves with the help of flagella, attached at the anterior of the organism and pushing it forward in the manner of a propeller. They interact hydrodynamically with the surrounding fluid and, because of their asymmetrical shape, have the propensity to align with the local flow. This, along with the dipolar nature of bacteria (the two forces a bacterium exerts on a fluid - one due to self-propulsion and the other opposing drag - have equal magnitude and point in opposite directions), causes nearby bacteria to tend to align, resulting in a intermittent local ordering on the mesoscopic scale, which is between the microscopic scale of an individual bacterium and the macroscopic scale of the suspension (e.g., its container). The local ordering is sometimes called a collective mode or collective swimming. Thanks to self-propulsion, collective modes inject momentum into the fluid in a coherent way. This enhances the local strain rate without changing the macroscopic stress applied at the boundary of the container. The macroscopic effective viscosity of the suspension is defined roughly as the ratio of the applied stress to the bulk strain rate. If local alignment and therefore local strain-rate enhancement, are significant, the effective viscosity can be appreciably lower than that of the corresponding passive suspension or even of the surrounding fluid alone. Indeed, a sevenfold decrease in the effective viscosity was observed in experiments with B. subtilis. More generally, local collective

  20. Structure and rheology of nanoparticle–polymer suspensions

    KAUST Repository

    Srivastava, Samanvaya

    2012-01-01

    Structure and rheology of oligomer-tethered nanoparticles suspended in low molecular weight polymeric host are investigated at various particle sizes and loadings. Strong curvature effects introduced by the small size of the nanoparticle cores are found to be important for understanding both the phase stability and rheology of the materials. Small angle X-ray scattering (SAXS) and transmission electron microscopy measurements indicate that PEG-SiO 2/PEG suspensions are more stable against phase separation and aggregation than expected from theory for interacting brushes. SAXS and rheology measurements also reveal that at high particle loadings, the stabilizing oligomer brush is significantly compressed and produces jamming in the suspensions. The jamming transition is accompanied by what appears to be a unique evolution in the transient suspension rheology, along with large increments in the zero-shear, Newtonian viscosity. The linear and nonlinear flow responses of the jammed suspensions are discussed in the framework of the Soft Glassy Rheology (SGR) model, which is shown to predict many features that are consistent with experimental observations, including a two-step relaxation following flow cessation and a facile method for determining the shear-thinning coefficient from linear viscoelastic measurements. Finally, we show that the small sizes of the particles have a significant effect on inter-particle interactions and rheology, leading to stronger deviations from expectations based on planar brushes and hard-sphere suspension theories. In particular, we find that in the high volume fraction limit, tethered nanoparticles interact in their host polymer through short-range forces, which are more analogous to those between soft particles than between spherical polymer brushes. © 2012 The Royal Society of Chemistry.

  1. Constraint Embedding for Vehicle Suspension Dynamics

    Directory of Open Access Journals (Sweden)

    Jain Abhinandan

    2016-06-01

    Full Text Available The goal of this research is to achieve close to real-time dynamics performance for allowing auto-pilot in-the-loop testing of unmanned ground vehicles (UGV for urban as well as off-road scenarios. The overall vehicle dynamics performance is governed by the multibody dynamics model for the vehicle, the wheel/terrain interaction dynamics and the onboard control system. The topic of this paper is the development of computationally efficient and accurate dynamics model for ground vehicles with complex suspension dynamics. A challenge is that typical vehicle suspensions involve closed-chain loops which require expensive DAE integration techniques. In this paper, we illustrate the use the alternative constraint embedding technique to reduce the cost and improve the accuracy of the dynamics model for the vehicle.

  2. Front-End Types. Automotive Mechanics. Steering & Suspension. Instructor's Guide [and] Student Guide.

    Science.gov (United States)

    Spignesi, B.

    This instructional package, one in a series of individualized instructional units on automotive steering and suspension, consists of a student guide and an instructor guide dealing with automobile front-end types. Covered in the module are three common types of passenger car front suspension systems and their major components as well as two types…

  3. The Mystical Suspension

    Directory of Open Access Journals (Sweden)

    Héctor Santiesteban Oliva

    2016-11-01

    Full Text Available Mistical suspension, silence, time, absolute, ontology, ineffability, aletheiaIn the mystical ecstasy there is a sensorial and intellectual suspension when contemplating the absolute, the ontological Being. Silence is not only significant: it is revealing. The greatest expression of experience inner silence . The word is insufficient when the ontological reality is revealed. Revelation or truth , the Greek concept of aletheia, takes on greater significance in that transcendental experience. It is also suspended phenomenological time and remains eternity open.

  4. Development of a scalable suspension culture for cardiac differentiation from human pluripotent stem cells

    Directory of Open Access Journals (Sweden)

    Vincent C. Chen

    2015-09-01

    Full Text Available To meet the need of a large quantity of hPSC-derived cardiomyocytes (CM for pre-clinical and clinical studies, a robust and scalable differentiation system for CM production is essential. With a human pluripotent stem cells (hPSC aggregate suspension culture system we established previously, we developed a matrix-free, scalable, and GMP-compliant process for directing hPSC differentiation to CM in suspension culture by modulating Wnt pathways with small molecules. By optimizing critical process parameters including: cell aggregate size, small molecule concentrations, induction timing, and agitation rate, we were able to consistently differentiate hPSCs to >90% CM purity with an average yield of 1.5 to 2 × 109 CM/L at scales up to 1 L spinner flasks. CM generated from the suspension culture displayed typical genetic, morphological, and electrophysiological cardiac cell characteristics. This suspension culture system allows seamless transition from hPSC expansion to CM differentiation in a continuous suspension culture. It not only provides a cost and labor effective scalable process for large scale CM production, but also provides a bioreactor prototype for automation of cell manufacturing, which will accelerate the advance of hPSC research towards therapeutic applications.

  5. Solid oxide fuel cell electrolytes produced via very low pressure suspension plasma spray and electrophoretic deposition

    Science.gov (United States)

    Fleetwood, James D.

    Solid oxide fuel cells (SOFCs) are a promising element of comprehensive energy policies due to their direct mechanism for converting the oxidization of fuel, such as hydrogen, into electrical energy. Both very low pressure plasma spray and electrophoretic deposition allow working with high melting temperature SOFC suspension based feedstock on complex surfaces, such as in non-planar SOFC designs. Dense, thin electrolytes of ideal composition for SOFCs can be fabricated with each of these processes, while compositional control is achieved with dissolved dopant compounds that are incorporated into the coating during deposition. In the work reported, sub-micron 8 mole % Y2O3-ZrO2 (YSZ) and gadolinia-doped ceria (GDC), powders, including those in suspension with scandium-nitrate dopants, were deposited on NiO-YSZ anodes, via very low pressure suspension plasma spray (VLPSPS) at Sandia National Laboratories' Thermal Spray Research Laboratory and electrophoretic deposition (EPD) at Purdue University. Plasma spray was carried out in a chamber held at 320 - 1300 Pa, with the plasma composed of argon, hydrogen, and helium. EPD was characterized utilizing constant current deposition at 10 mm electrode separation, with deposits sintered from 1300 -- 1500 °C for 2 hours. The role of suspension constituents in EPD was analyzed based on a parametric study of powder loading, powder specific surface area, polyvinyl butyral (PVB) content, polyethyleneimine (PEI) content, and acetic acid content. Increasing PVB content and reduction of particle specific surface area were found to eliminate the formation of cracks when drying. PEI and acetic acid content were used to control suspension stability and the adhesion of deposits. Additionally, EPD was used to fabricate YSZ/GDC bilayer electrolyte systems. The resultant YSZ electrolytes were 2-27 microns thick and up to 97% dense. Electrolyte performance as part of a SOFC system with screen printed LSCF cathodes was evaluated with peak

  6. Assessment of drug salt release from solutions, suspensions and in situ suspensions using a rotating dialysis cell

    DEFF Research Database (Denmark)

    Parshad, Henrik; Frydenvang, Karla; Liljefors, Tommy

    2003-01-01

    buffer is used as release media. Generally, the initial release of the drug salt from in situ suspensions occurred faster as compared to conventional suspensions, probably due to incomplete precipitation of the drug salt, and hence formation of supersaturated solutions where the rate of release......A rotating dialysis cell consisting of a small (10 ml) and a large compartment (1000 ml) was used to study the release of drug salt (bupivacaine 9-anthracene carboxylate) from (i). solutions, (ii). suspensions and (iii). in situ formed suspensions. Initial release experiments from suspensions...... indicated that the release of drug salt in deionized water was predominantly limited by the diffusion across the membrane whereas it is essentially dissolution rate controlled in 0.05 M phosphate buffer (pH 7.40). Thus, the in vitro model appears to have a potential in formulation screening when phosphate...

  7. Synchrotron SAXS/WAXD and rheological studies of clay suspensions in silicone fluid.

    Science.gov (United States)

    Zhang, Li-Ming; Jahns, Christopher; Hsiao, Benjamin S; Chu, Benjamin

    2003-10-15

    Suspensions of two commercial smectite clays, montmorillonite KSF and montmorillonite K10, in a low-viscosity silicone oil (Dow Corning 245 Fluid) were studied by simultaneous synchrotron small-angle X-ray scattering (SAXS)/wide-angle X-ray diffraction (WAXD) techniques and rheological measurements. In the 0.5% (w/v) KSF clay suspension and two K10 clay suspensions (0.5% and 1.0%), WAXD profiles below 2theta=10.0 degrees did not display any characteristic reflection peaks associated with the chosen montmorillonite clays, while corresponding SAXS profiles exhibited distinct scattering maxima, indicating that both clays were delaminated by the silicone oil. In spite of the large increase in viscosity, the clay suspensions exhibited no gel characteristics. Dynamic rheological experiments indicated that the clay/silicone oil suspensions exhibited the behavior of viscoelasticity, which could be influenced by the type and the concentration of the clay. For the K10 clay suspensions, the frequency-dependent loss modulus (G") was greater in magnitude than the storage modulus (G') in the concentration range from 0.5 to 12.0%. The increase in the clay concentration shifted the crossover point between G' and G" into the accessible frequency range, indicating that the system became more elastic. In contrast, the KSF clay suspension exhibited lower G' and G" values, indicating a weaker viscoelastic response. The larger viscoelasticity response in the K10 clay suspension may be due to the acid treatment generating a higher concentration of silanol groups on the clay surface.

  8. Flow-induced structure in colloidal suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Vermant, J [Department of Chemical Engineering, K U Leuven, W de Croylaan 46, B-3001 Leuven (Belgium); Solomon, M J [Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109-2136 (United States)

    2005-02-02

    We review the sequences of structural states that can be induced in colloidal suspensions by the application of flow. Structure formation during flow is strongly affected by the delicate balance among interparticle forces, Brownian motion and hydrodynamic interactions. The resulting non-equilibrium microstructure is in turn a principal determinant of the suspension rheology. Colloidal suspensions with near hard-sphere interactions develop an anisotropic, amorphous structure at low dimensionless shear rates. At high rates, clustering due to strong hydrodynamic forces leads to shear thickening rheology. Application of steady-shear flow to suspensions with repulsive interactions induces a rich sequence of transitions to one-, two-and three-dimensional order. Oscillatory-shear flow generates metastable ordering in suspensions with equilibrium liquid structure. On the other hand, short-range attractive interactions can lead to a fluid-to-gel transition under quiescent suspensions. Application of flow leads to orientation, breakup, densification and spatial reorganization of aggregates. Using a non-Newtonian suspending medium leads to additional possibilities for organization. We examine the extent to which theory and simulation have yielded mechanistic understanding of the microstructural transitions that have been observed. (topical review)

  9. Naratriptan hydrochloride in extemporaneosly compounded oral suspensions.

    Science.gov (United States)

    Zhang, Y P; Trissel, L A; Fox, J L

    2000-01-01

    The purpose of this study was to determine the pharmaceutical acceptability and chemical stability of naratriptan hydrochloride in three extemporaneously compounded suspension formulations. The naratriptan-hydrochloride oral suspensions were prepared from 2.5-mg commercial tablets yielding a nominal naratriptan concentration of 0.5 mg/mL. The suspension vehicles selected for testing were Syrpalta, an equal-parts mixture of Ora-Plus and Ora-Sweet, and an equal-parts mixture of Ora-Plus and Ora-Sweet SF. The tablets were crushed and thoroughly triturated to a fine powder using a porcelain mortar and pestle. The powder was incorporated into a portion of the Syrpalta or Ora-Plus suspension vehicle and mixed until homogeneous. The mixtures were then brought to volume with Syrpalta, Ora-Sweet or Ora-Sweet SF, as appropriate. The suspensions were packaged in amber, plastic, screw-cap prescription bottles and stored at 23 deg C for seven days and 4 deg C for 90 days. An adequate suspension was never achieved in Syrpalta. The crushed-tablet powder did not produce a uniformly dispersed mixture and exhibited clumping and a high rate of sedimentation. A distinct layer of the solid tablet material settled immediately after shaking. Over the next four hours, a densely packed, yellow, caked layer formed at the bottom of the containers, making resuspension difficult. During storage, the caking became worse. Chemical analysis was not performed. The Ora-Plus and Ora-Sweet or Ora-Sweet SF suspensions had a slight greenish cast and were resuspended without difficulty by shaking for approximately ten seconds, yielding easily poured and homogeneous mixtures throughout the study. Visible settling and layering did not begin for four hours with the Ora-Sweet suspension and 24 hours for the Ora-Sweet SF suspension. High pressure liquid chromatographic analysis found that the naratriptan concentration in both suspension-vehicle combinations exhibited little or no loss for seven days at 23

  10. Velocity and size distribution measurement of suspension droplets using PDPA technique

    Science.gov (United States)

    Amiri, Shahin; Akbarnozari, Ali; Moreau, Christian; Dolatabadi, Ali

    2015-11-01

    The creation of fine and uniform droplets from a bulk of liquid is a vital process in a variety of engineering applications, such as atomization in suspension plasma spray (SPS) in which the submicron coating materials are injected to the plasma gas through the suspension droplets. The size and velocity of these droplets has a great impact on the interaction of the suspension with the gas flow emanating from a plasma torch and can consequently affect the mechanical and chemical properties of the resultant coatings. In the current study, an aqueous suspension of small glass particles (2-8 μm) was atomized by utilizing an effervescent atomizer of 1 mm orifice diameter which involves bubbling gas (air) directly into the liquid stream. The gas to liquid ratio (GLR) was kept constant at 6% throughout this study. The mass concentration of glass particles varied in the range between 0.5 to 5% in order to investigate the effect of suspension viscosity and surface tension on the droplet characteristics, such as velocity and size distributions. These characteristics were simultaneously measured by using a non-intrusive optical technique, Phase Doppler Particle Anemometry (PDPA), which is based on the light signal scattered from the droplets moving in a measurement volume. The velocity and size distribution of suspension droplets were finally compared to those of distilled water under identical conditions. The results showed a different atomization behaviors due to the reduction in surface tension of the suspension spray.

  11. Do rice suspension-cultured cells treated with abscisic acid mimic developing seeds?

    Science.gov (United States)

    Matsuno, Koya; Fujimura, Tatsuhito

    2015-08-01

    Starch synthesis is activated in the endosperm during seed development and also in rice suspension cells cultured with abscisic acid. In the anticipation that the mechanisms of starch synthesis are similar between the endosperm and the suspension cells cultured with abscisic acid, expression of genes involved in starch synthesis was evaluated in the suspension cells after abscisic acid treatment. However, it was found that the regulatory mechanism of starch synthesis in the suspension cells cultured with abscisic acid was different from that in developing seeds. Expression analyses of genes involved in oil bodies, which accumulate in the embryo and aleurone layer, and seed storage proteins, which accumulate mainly in the endosperm, showed that the former were activated in the suspension cells cultured with abscisic acid, but the latter were not. Master regulators for embryogenesis, OsVP1 (homologue of AtABI3) and OsLFL1 (homologue of AtFUS3 or AtLFL2), were expressed in the suspension cells at levels comparable to those in the embryo. From these results, it is suggested that interactions between regulators and abscisic acid control the synthesis of phytic acid and oil bodies in the cultured cells and embryo. We suggest that the system of suspension cells cultured with abscisic acid helps to reveal the mechanisms of phytic acid and oil body synthesis in embryo.

  12. Characterization of cell suspensions from solid tumors

    International Nuclear Information System (INIS)

    Pallavicini, M.

    1985-01-01

    The desirable features of cells in suspension will necessarily be dependent upon the use for which the cells were prepared. Adequate cell yield or recovery is defined by the measurement to be performed. Retention of cellular morphology is important for microscopic identification of cell types in a heterogenous cell suspension, and may be used to determine whether the cells in suspension are representative of those in the tumor in situ. Different dispersal protocols may yield cells with different degrees of clonogenicity, as well as altered biochemical features, such as loss of cellular proteins, surface antigens, nucleotide pools, etc. The quality of the cell suspension can be judged by the degree of cell clumping and level of cellular debris, both of which impact on flow cytometric measurements and studies in which the number of cells be known accurately. Finally, if the data measured on the cells in suspension are to be extrapolated to phenomena occurring in the tumor in situ, it is desirable that the cells in suspension are representative of those in the solid tumor in vivo. This report compares characteristics of tumor cell suspensions obtained by different types of selected disaggregation methods. 33 refs., 2 figs., 4 tabs

  13. Measuring the Impact of Gastrointestinal Variables on the Systemic Outcome of Two Suspensions of Posaconazole by a PBPK Model.

    Science.gov (United States)

    Hens, Bart; Talattof, Arjang; Paixão, Paulo; Bermejo, Marival; Tsume, Yasuhiro; Löbenberg, Raimar; Amidon, Gordon L

    2018-03-29

    For the last two decades, the application of physiologically based pharmacokinetic (PBPK) models has grown exponentially in the field of oral absorption and in a regulatory context. Although these models are widely used, their predictive power should be validated and optimized in order to rely on these models and to know exactly what is going on "under the hood". In this study, an automated sensitivity analysis (ASA) was performed for 11 gastrointestinal (GI) variables that are integrated into the PBPK software program Simcyp®. The model of interest was a previously validated workspace that was able to predict the intraluminal and systemic behavior of two different suspensions of posaconazole in the Simcyp® Simulator. The sensitivity of the following GI parameters was evaluated in this model: gastric and duodenal pH, gastric and duodenal bicarbonate concentrations (reflecting buffer capacity), duodenal bile salts concentration, gastric emptying, the interdigestive migrating motor complex (IMMC), small intestinal transit time (SITT), gastric and jejunal volumes, and permeability. The most sensitive parameters were gastric/duodenal pH and gastric emptying, for both suspensions. The outcome of the sensitivity analyses highlights the important GI variables that must be integrated into an in vivo predictive dissolution test to help and create a rational and scientific framework/design for product development of novel and generic drug products.

  14. Use of magnetic beads for Gram staining of bacteria in aqueous suspension.

    Science.gov (United States)

    Yazdankhah, S P; Sørum, H; Larsen, H J; Gogstad, G

    2001-12-01

    A Gram staining technique was developed using monodisperse magnetic beads in concentrating bacteria in suspension for downstream application. The technique does not require heat fixation of organisms, electrical power, or a microscope. Gram-negative and Gram-positive bacteria were identified macroscopically based on the colour of the suspension. The bacteria concentrated on magnetic beads may also be identified microscopically.

  15. Characterizing viscoelasticity of unhydrolyzed chicken sternal cartilage extract suspensions: Towards development of injectable therapeutics formulations.

    Science.gov (United States)

    Hama, Brian; Mahajan, Gautam; Kothapalli, Chandrasekhar

    2017-08-01

    Exogenous delivery of cartilage extract is being explored as a promising candidate for knee arthritis treatment as it biomimics native cartilage tissue characteristics. In this study, we report on the rheological characterization of aqueous suspensions constituted from a powdered form of unhydrolyzed chicken sternum extract. The effect of particle size (as-received vs. milled), suspension fluid (water vs. PBS), and temperature (37°C vs. 4°C), on the viscoelastic properties of the sternum extract based particulate suspensions were evaluated. Results showed that these suspensions exhibit shear-thinning characteristics as shear rate (γ̇) increases, while viscosity (η), storage (G'), and loss (G″) moduli of the suspensions increased with increasing particulate loading (ϕ: 2.5-10wt%). Reducing the as-received particle size by milling decreased G', G, and η of the suspensions and increased the influence of ϕ on these properties, possibly due to improved particle packing. Replacing water with PBS had no significant effect on the rheological properties, but temperature reduction from 37°C to 4°C increased G', G", and η of the suspensions and lowered the impact of powder loading on viscoelastic properties. The suspension's time-dependent response was typical of viscoelastic materials, characterized by an asymptotical approach to a final stress (stress relaxation) or strain (creep). Results were fit to a power-law model for creep, a general relaxation model for exponential decay in stress, Carreau-Yasuda models for flow curves, and a two-parameter Liu model to identify the maximum powder loading (ϕ m ). Among the various forces involved in particle-particle interactions within these suspensions, electrostatic forces appeared to dominate the most. Such characterization of the viscoelastic nature of these suspensions would help in formulating stable injectable cartilage extract based therapeutics for in vivo applications. Copyright © 2017 Elsevier Ltd. All

  16. Smectite clay--inorganic nanoparticle mixed suspensions: phase behaviour and rheology.

    Science.gov (United States)

    Bailey, Louise; Lekkerkerker, Henk N W; Maitland, Geoffrey C

    2015-01-14

    Smectite clay minerals and their suspensions have long been of both great scientific and applications interest and continue to display a remarkable range of new and interesting behaviour. Recently there has been an increasing interest in the properties of mixed suspensions of such clays with nanoparticles of different size, shape and charge. This review aims to summarize the current status of research in this area focusing on phase behaviour and rheological properties. We will emphasize the rich range of data that has emerged for these systems and the challenges they present for future investigations. The review starts with a brief overview of the behaviour and current understanding of pure smectite clays and their suspensions. We then cover the work on smectite clay-inorganic nanoparticle mixed suspensions according to the shape and charge of the nanoparticles - spheres, rods and plates either positively or negatively charged. We conclude with a summary of the overarching trends that emerge from these studies and indicate where gaps in our understanding need further research for better understanding the underlying chemistry and physics.

  17. Non-linear Characteristic Modeling of Frictional Suspension Using Measured Data

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Chang Gyu; Jang, Jin Seok; Jin, Jae Hoon; Yoo, Wan Suk [Pusan National University, Busan (Korea, Republic of)

    2015-01-15

    Large-capacity of household washing machine can become unbalanced during the dehydration process. To solve this problem, several types of suspensions have been installed in a washing machine. In this study, physical tests were carried out on a frictional suspension, and the nonlinear characteristics were modeled by combining several simple physical models. The parameters were estimated based on the least squares solution. The simulation and test results were compared to verify the validity of the friction damper model.

  18. 13 CFR 120.660 - Suspension or revocation.

    Science.gov (United States)

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Suspension or revocation. 120.660 Section 120.660 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION BUSINESS LOANS Secondary Market Suspension Or Revocation of Participant in Secondary Market § 120.660 Suspension or revocation. (a...

  19. Low Reynolds number suspension gravity currents.

    Science.gov (United States)

    Saha, Sandeep; Salin, Dominique; Talon, Laurent

    2013-08-01

    The extension of a gravity current in a lock-exchange problem, proceeds as square root of time in the viscous-buoyancy phase, where there is a balance between gravitational and viscous forces. In the presence of particles however, this scenario is drastically altered, because sedimentation reduces the motive gravitational force and introduces a finite distance and time at which the gravity current halts. We investigate the spreading of low Reynolds number suspension gravity currents using a novel approach based on the Lattice-Boltzmann (LB) method. The suspension is modeled as a continuous medium with a concentration-dependent viscosity. The settling of particles is simulated using a drift flux function approach that enables us to capture sudden discontinuities in particle concentration that travel as kinematic shock waves. Thereafter a numerical investigation of lock-exchange flows between pure fluids of unequal viscosity, reveals the existence of wall layers which reduce the spreading rate substantially compared to the lubrication theory prediction. In suspension gravity currents, we observe that the settling of particles leads to the formation of two additional fronts: a horizontal front near the top that descends vertically and a sediment layer at the bottom which aggrandises due to deposition of particles. Three phases are identified in the spreading process: the final corresponding to the mutual approach of the two horizontal fronts while the laterally advancing front halts indicating that the suspension current stops even before all the particles have settled. The first two regimes represent a constant and a decreasing spreading rate respectively. Finally we conduct experiments to substantiate the conclusions of our numerical and theoretical investigation.

  20. Constitutive relation for the system-spanning dynamically jammed region in response to impact of cornstarch and water suspensions

    Science.gov (United States)

    Maharjan, Rijan; Mukhopadhyay, Shomeek; Allen, Benjamin; Storz, Tobias; Brown, Eric

    2018-05-01

    We experimentally characterize the impact response of concentrated suspensions consisting of cornstarch and water. We observe that the suspensions support a large normal stress—on the order of MPa—with a delay after the impactor hits the suspension surface. We show that neither the delay nor the magnitude of the stress can yet be explained by either standard rheological models of shear thickening in terms of steady-state viscosities, or impact models based on added mass or other inertial effects. The stress increase occurs when a dynamically jammed region of the suspension in front of the impactor propagates to the opposite boundary of the container, which can support large stresses when it spans between solid boundaries. We present a constitutive relation for impact rheology to relate the force on the impactor to its displacement. This can be described in terms of an effective modulus but only after the delay required for the dynamically jammed region to span between solid boundaries. Both the modulus and the delay are reported as a function of impact velocity, fluid height, and weight fraction. We report in a companion paper the structure of the dynamically jammed region when it spans between the impactor and the opposite boundary [Allen et al., Phys. Rev. E 97, 052603 (2018), 10.1103/PhysRevE.97.052603]. In a direct follow-up paper, we show that this constitutive model can be used to quantitatively predict, for example, the trajectory and penetration depth of the foot of a person walking or running on cornstarch and water [Mukhopadhyay et al., Phys. Rev. E 97, 052604 (2018), 10.1103/PhysRevE.97.052604].

  1. Gasification of peat and biomass in suspension. Turpeen ja biomassan suspensiokaasutus

    Energy Technology Data Exchange (ETDEWEB)

    Haukka, P.; Raiko, R.

    1993-01-01

    Gasification of peat and biomass in dilute particle-gas suspension has not been studied significantly in Finland, even though these fuels require drying, which often produces dry pulverized fuel. This report has concentrated on studying suitability of so-called two-stage entrained-bed gasification for peat and biomass. The gasification system consists of a pyrolysis reactor (entrained flow) and an adiabatic char combustor. Dry or almost dry fuel is fed into the hot flue gas stream coming from the char combustor. Gasification is based on flash pyrolysis in the dilute suspension flow. Residual char is separated from pyrolyzer gases in a gas cleaning device and fed back to the adiabatic combustor. In the combustor char is burned at high temperature to supply the heat required to support endothermic reactions occurring in the pyrolyzer. To study entrained-bed gasification two types of computer models were developed: steady state simulation model and kinetic pyrolyzer model. With the help of these computer models mass and energy balances of the gasifier can be solved and the main dimensions of the gasifier can be determined. Lack of proper kinetic parameters for fast pyrolysis of peat and biomass makes it more difficult to apply the kinetic model in practice. Quantitative data concerning fast pyrolysis in dilute gas-particle suspension are needed to be able to evaluate the performance of the suspension gasifier in more detail. Gasifier operation has been studied using three different levels for amounts of pyrolysis pro- ducts, nine pressure levels between 15-23 bars and five temperature levels between 800-1200 deg C. Furthermore, normal pressure performance was simulated. In addition to simulation studies product gas heating value was optimized

  2. Quadruple suspension design for Advanced LIGO

    International Nuclear Information System (INIS)

    Robertson, N A; Cagnoli, G; Crooks, D R M; Elliffe, E; Faller, J E; Fritschel, P; Gossler, S; Grant, A; Heptonstall, A; Hough, J; Lueck, H; Mittleman, R; Perreur-Lloyd, M; Plissi, M V; Rowan, S; Shoemaker, D H; Sneddon, P H; Strain, K A; Torrie, C I; Ward, H; Willems, P

    2002-01-01

    In this paper, we describe the conceptual design for the suspension system for the test masses for Advanced LIGO, the planned upgrade to LIGO, the US laser interferometric gravitational-wave observatory. The design is based on the triple pendulum design developed for GEO 600 - the German/UK interferometric gravitational wave detector. The GEO design incorporates fused silica fibres of circular cross-section attached to the fused silica mirror (test mass) in the lowest pendulum stage, in order to minimize the thermal noise from the pendulum modes. The damping of the low-frequency modes of the triple pendulum is achieved by using co-located sensors and actuators at the highest mass of the triple pendulum. Another feature of the design is that global control forces acting on the mirrors, used to maintain the output of the interferometer on a dark fringe, are applied via a triple reaction pendulum, so that these forces can be implemented via a seismically isolated platform. These techniques have been extended to meet the more stringent noise levels planned for in Advanced LIGO. In particular, the Advanced LIGO baseline design requires a quadruple pendulum with a final stage consisting of a 40 kg sapphire mirror, suspended on fused silica ribbons or fibres. The design is chosen to aim to reach a target noise contribution from the suspension corresponding to a displacement sensitivity of 10 -19 m Hz -1/2 at 10 Hz at each of the test masses

  3. Shear thinning and shear thickening of a confined suspension of vesicles

    Science.gov (United States)

    Nait Ouhra, A.; Farutin, A.; Aouane, O.; Ez-Zahraouy, H.; Benyoussef, A.; Misbah, C.

    2018-01-01

    Widely regarded as an interesting model system for studying flow properties of blood, vesicles are closed membranes of phospholipids that mimic the cytoplasmic membranes of red blood cells. In this study we analyze the rheology of a suspension of vesicles in a confined geometry: the suspension, bound by two planar rigid walls on each side, is subject to a shear flow. Flow properties are then analyzed as a function of shear rate γ ˙, the concentration of the suspension ϕ , and the viscosity contrast λ =ηin/ηout , where ηin and ηout are the fluid viscosities of the inner and outer fluids, respectively. We find that the apparent (or effective viscosity) of the suspension exhibits both shear thinning (decreasing viscosity with shear rate) or shear thickening (increasing viscosity with shear rate) in the same concentration range. The shear thinning or thickening behaviors appear as subtle phenomena, dependant on viscosity contrast λ . We provide physical arguments on the origins of these behaviors.

  4. Time Varying Behavior of the Loudspeaker Suspension

    DEFF Research Database (Denmark)

    Pedersen, Bo Rohde; Agerkvist, Finn T.

    2007-01-01

    The suspension part of the electrodynamic loudspeaker is often modelled as a simple linear spring with viscous damping, however the dynamic behaviour of the suspension is much more complicated than predicted by such a simple model. At higher levels the compliance becomes non-linear and often chan...... changes during excitation at high levels. This paper investigates how the compliance of the suspension depends on the excitation, i.e. level and frequency content. The measurements are compared with other known measurement methods of the suspension....

  5. Study on kinematic and compliance test of suspension

    Science.gov (United States)

    Jing, Lixin; Wu, Liguang; Li, Xuepeng; Zhang, Yu

    2017-09-01

    Chassis performance development is a major difficulty in vehicle research and development, which is the main factor restricting the independent development of vehicles in China. These years, through a large number of studies, chassis engineers have found that the suspension K&C characteristics as a quasi-static characteristic of the suspension provides a technical route for the suspension performance R&D, and the suspension K&C test has become an important means of vehicle benchmarking, optimization and verification. However, the research on suspension K&C test is less in china, and the test conditions and setting requirements vary greatly from OEM to OEM. In this paper, the influence of different settings on the characteristics of the suspension is obtained through experiments, and the causes of the differences are analyzed; in order to fully reflect the suspension characteristics, the author recommends the appropriate test case and settings.

  6. 21 CFR 1301.36 - Suspension or revocation of registration; suspension of registration pending final order...

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Suspension or revocation of registration; suspension of registration pending final order; extension of registration pending final order. 1301.36... registration pending final order; extension of registration pending final order. (a) For any registration...

  7. Combining support vector machines with linear quadratic regulator adaptation for the online design of an automotive active suspension system

    International Nuclear Information System (INIS)

    Chiou, J-S; Liu, M-T

    2008-01-01

    As a powerful machine-learning approach to pattern recognition problems, the support vector machine (SVM) is known to easily allow generalization. More importantly, it works very well in a high-dimensional feature space. This paper presents a nonlinear active suspension controller which achieves a high level performance by compensating for actuator dynamics. We use a linear quadratic regulator (LQR) to ensure optimal control of nonlinear systems. An LQR is used to solve the problem of state feedback and an SVM is used to address the question of the estimation and examination of the state. These two are then combined and designed in a way that outputs feedback control. The real-time simulation demonstrates that an active suspension using the combined SVM-LQR controller provides passengers with a much more comfortable ride and better road handling

  8. Semi-active H∞ control of high-speed railway vehicle suspension with magnetorheological dampers

    Science.gov (United States)

    Zong, Lu-Hang; Gong, Xing-Long; Xuan, Shou-Hu; Guo, Chao-Yang

    2013-05-01

    In this paper, semi-active H∞ control with magnetorheological (MR) dampers for railway vehicle suspension systems to improve the lateral ride quality is investigated. The proposed semi-active controller is composed of a H∞ controller as the system controller and an adaptive neuro-fuzzy inference system (ANFIS) inverse MR damper model as the damper controller. First, a 17-degree-of-freedom model for a full-scale railway vehicle is developed and the random track irregularities are modelled. Then a modified Bouc-Wen model is built to characterise the forward dynamic characteristics of the MR damper and an inverse MR damper model is built with the ANFIS technique. Furthermore, a H∞ controller composed of a yaw motion controller and a rolling pendulum motion (lateral motion+roll motion) controller is established. By integrating the H∞ controller with the ANFIS inverse model, a semi-active H∞ controller for the railway vehicle is finally proposed. Simulation results indicate that the proposed semi-active suspension system possesses better attenuation ability for the vibrations of the car body than the passive suspension system.

  9. 39 CFR 3001.114 - Suspension pending review.

    Science.gov (United States)

    2010-07-01

    ... 39 Postal Service 1 2010-07-01 2010-07-01 false Suspension pending review. 3001.114 Section 3001... Suspension pending review. (a) Application. Application for suspension of a determination of the Postal Service to close or consolidate any post office pending the outcome of an appeal to the Postal Regulatory...

  10. 21 CFR 520.905a - Fenbendazole suspension.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Fenbendazole suspension. 520.905a Section 520.905a... DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.905a Fenbendazole suspension. (a) Specifications. Each milliliter of suspension contains 100 milligrams (mg) fenbendazole. (b...

  11. Inertia Wheel on Low-Noise Active Magnetic Suspension

    Science.gov (United States)

    Carabelli, S.; Genta, G.; Silvagni, M.; Tonoli, A.

    2002-01-01

    Magnetic bearings are particularly suited for space applications for a number of reasons: - they are ideally suited for vacuum applications; - the lack of lubrication and wear enhances the reliability and guaranties a long maintenance-free operation - the low drag torque decreases power consumption and reduces the torque exerted on the stator of the machine. - the possibility of insulating actively the spacecraft from the excitation due to unbalance of the rotating system In the case of reaction wheels, a well designed magnetic suspension allows high speed operation with a very low power consumption and vibration level. Conversely, microgravity (and possibly vacuum) operation is an advantage for magnetic bearings. The absence of static forces allows to operate with low current levels, thus reducing electrical noise and allowing to reach even lower vibration levels than in Earth applications of magnetic bearings. Active magnetic bearings (AMB) allow to adapt the working characteristics of the system to the operating needs: it is possible to use the actuators to lock the system during launch (absence of grabbers) and to stiffen the suspension when the spacecraft is accelerated (impulsive phases), while working in conditions optimised for microgravity when this is needed. Magnetic suspension systems designed for microgravity environment cannot be correctly tested on the ground. Testing in ground conditions results in the need of grossly overdesigning the levitation device; furthermore, in some cases ground testing is completely impossible, if not by introducing devices which compensate for the Earth gravitational field. If the compensation for the gravitational force is supplied by the same actuators used for microgravity operation, the actuators and the power amplifiers must be overdesigned and in some cases the suspension can be altogether impossible. They work in conditions which are much different from nominal ones and, above all, it is impossible to reach the

  12. Core Muscle Activation in Suspension Training Exercises.

    Science.gov (United States)

    Cugliari, Giovanni; Boccia, Gennaro

    2017-02-01

    A quantitative observational laboratory study was conducted to characterize and classify core training exercises executed in a suspension modality on the base of muscle activation. In a prospective single-group repeated measures design, seventeen active male participants performed four suspension exercises typically associated with core training (roll-out, bodysaw, pike and knee-tuck). Surface electromyographic signals were recorded from lower and upper parts of rectus abdominis, external oblique, internal oblique, lower and upper parts of erector spinae muscles using concentric bipolar electrodes. The average rectified values of electromyographic signals were normalized with respect to individual maximum voluntary isometric contraction of each muscle. Roll-out exercise showed the highest activation of rectus abdominis and oblique muscles compared to the other exercises. The rectus abdominis and external oblique reached an activation higher than 60% of the maximal voluntary contraction (or very close to that threshold, 55%) in roll-out and bodysaw exercises. Findings from this study allow the selection of suspension core training exercises on the basis of quantitative information about the activation of muscles of interest. Roll-out and bodysaw exercises can be considered as suitable for strength training of rectus abdominis and external oblique muscles.

  13. Non-homogeneous flow profiles in sheared bacterial suspensions

    Science.gov (United States)

    Samanta, Devranjan; Cheng, Xiang

    Bacterial suspensions under shear exhibit interesting rheological behaviors including the remarkable ``superfluidic'' state with vanishing viscosity at low shear rates. Theoretical studies have shown that such ``superfluidic'' state is linked with non-homogeneous shear flows, which are induced by coupling between nematic order of active fluids and hydrodynamics of shear flows. However, although bulk rheology of bacterial suspensions has been experimentally studied, shear profiles within bacterial suspensions have not been explored so far. Here, we experimentally investigate the flow behaviors of E. coli suspensions under planar oscillatory shear. Using confocal microscopy and PIV, we measure velocity profiles across gap between two shear plates. We find that with increasing shear rates, high-concentration bacterial suspensions exhibit an array of non-homogeneous flow behaviors like yield-stress flows and shear banding. We show that these non-homogeneous flows are due to collective motion of bacterial suspensions. The phase diagram of sheared bacterial suspensions is systematically mapped as functions of shear rates an bacterial concentrations. Our experiments provide new insights into rheology of bacterial suspensions and shed light on shear induced dynamics of active fluids. Chemical Engineering and Material Science department.

  14. Partitioning and Dissolution Behavior of Metal-based Engineered Nanoparticles in Sediment and Soil Suspensions

    Directory of Open Access Journals (Sweden)

    Koetsem F. Van

    2013-04-01

    Full Text Available Nowadays engineered nanoparticles are being used in a whole range of commercial applications and are therefore expected to inevitably find their way into the environment where their fate and behavior are still largely unknown. The objective of this study was to investigate the behavior and fate of a number of engineered nanoparticles (CeO2, SnO2, Ag in sediment and soil suspensions. In particular, the association of nanoparticles with solid phases, the kinetics of these interactions, and the solubility of the nanoparticulate matter in sediment and soil suspensions were studied. Four different sediments and three different soils were sampled at various locations in Flanders (Belgium, dried, grinded and characterized. Sediment and soil suspensions were prepared with Milli-Q water (1/10 S/L, spiked with the different metallic nanoparticles or corresponding ions, and continuously shaken for 24 hours. At regular time intervals, samples of the suspensions were collected and centrifuged at 500 or 2000 rpm, or left for gravitational settling. The supernatant was analyzed for total metal contents after aqua regia digestion and for dissolved metal ions after centrifugal ultrafiltration. In a second experiment, the impact of centrifugation speed on the amount of suspended matter in the supernatant was also studied. Relations between soil or sediment properties, suspended matter and metals in the supernatant were investigated. First data already point towards a strong association of nanoparticles with suspended material. The remaining data are still being collected and will be presented at the conference.

  15. Drift tube suspension for high intensity linear accelerators

    International Nuclear Information System (INIS)

    Clark, D.C.; Frank, J.A.; Liska, D.J.; Potter, R.C.; Schamaun, R.G.

    1982-01-01

    The disclosure relates to a drift tube suspension for high intensity linear accelerators. The system comprises a series of box-sections girders independently adjustably mounted on a linear accelerator. A plurality of drift tube holding stems are individually adjustably mounted on each girder

  16. Drift tube suspension for high intensity linear accelerators

    Science.gov (United States)

    Liska, Donald J.; Schamaun, Roger G.; Clark, Donald C.; Potter, R. Christopher; Frank, Joseph A.

    1982-01-01

    The disclosure relates to a drift tube suspension for high intensity linear accelerators. The system comprises a series of box-sections girders independently adjustably mounted on a linear accelerator. A plurality of drift tube holding stems are individually adjustably mounted on each girder.

  17. 78 FR 20960 - Face Up Entertainment Group, Inc.; Order of Suspension of Trading

    Science.gov (United States)

    2013-04-08

    ... Suspension of Trading April 4, 2013. It appears to the Securities and Exchange Commission that there is a... business operations, and trading in its securities. Face Up is a Florida corporation based in Valley Stream... interest and the protection of investors require a suspension of trading in the securities of the above...

  18. 9 CFR 439.52 - Suspension of accreditation.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Suspension of accreditation. 439.52 Section 439.52 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE... of the following violations of law: (a) Any felony. (b) Any misdemeanor based upon acquiring...

  19. Clay particles as binder for earth buildings materials: a fresh look into rheology of dense clay suspensions

    Science.gov (United States)

    Landrou, Gnanli; Brumaud, Coralie; Habert, Guillaume

    2017-06-01

    In the ceramic industry and in many sectors, clay minerals are widely used. In earthen construction technique, clay plays a crucial role in the processing. The purpose of this research is to understand and modify the clay properties in earth material to propose an innovative strategy to develop a castable earth-based material. To do so, we focused on the modification of clay properties at fresh state with inorganic additives. As the rheological behaviour of clays is controlled by their surface charge, the addition of phosphate anion allows discussing deep the rheology of concentrated clay suspensions. We highlighted the thixotropic and shear thickening behaviour of a dispersed kaolinite clay suspensions. Indeed, by adding sodium hexametaphosphate the workability of clay paste increases and the behaviour is stable during time after a certain shear is applied. Moreover, we stress that the aging and the shift in critical strain in clay system are due to the re-arrangement of clay suspension and a decrease of deformation during time. The understanding of both effect: thixotropy and aging are crucial for better processing of clay-based material and for self-compacting clay concrete. Yet, studies need to pursue to better understand the mechanism.

  20. Average stress in a Stokes suspension of disks

    NARCIS (Netherlands)

    Prosperetti, Andrea

    2004-01-01

    The ensemble-average velocity and pressure in an unbounded quasi-random suspension of disks (or aligned cylinders) are calculated in terms of average multipoles allowing for the possibility of spatial nonuniformities in the system. An expression for the stress due to the suspended particles is

  1. Robust Tensioned Kevlar Suspension Design

    Science.gov (United States)

    Young, Joseph B.; Naylor, Bret J.; Holmes, Warren A.

    2012-01-01

    One common but challenging problem in cryogenic engineering is to produce a mount that has excellent thermal isolation but is also rigid. Such mounts can be achieved by suspending the load from a network of fibers or strings held in tension. Kevlar fibers are often used for this purpose owing to their high strength and low thermal conductivity. A suite of compact design elements has been developed to improve the reliability of suspension systems made of Kevlar.

  2. Ceramic Near-Net Shaped Processing Using Highly-Loaded Aqueous Suspensions

    Science.gov (United States)

    Rueschhoff, Lisa

    Ceramic materials offer great advantages over their metal counterparts, due to their lower density, higher hardness and wear resistance, and higher melting temperatures. However, the use of ceramics in applications where their properties would offer tremendous advantages are often limited due to the difficulty of forming them into complex and near-net shaped parts. Methods that have been developed to injection-mold or cast ceramics into more complicated shapes often use significant volume fractions of a carrier (often greater than 35 vol.% polymer), elevated temperature processing, or less-than-environmentally friendly chemicals where a complex chemical synthesis reaction must be timed perfectly for the approach to work. Furthermore, the continuing maturation of additive manufacturing methods requires a new approach for flowing/placing ceramic powders into useful designs. This thesis addresses the limitations of the current ceramic forming approaches by developing highly-stabilized and therefore high solids loading ceramic suspensions, with the requisite rheology for a variety of complex and near-net shaped forming techniques. Silicon nitride was chosen as a material of focus due to its high fracture toughness compared to other ceramic materials. Designing ceramic suspensions that are flowable at room temperature greatly simplifies processing as neither heating nor cooling are required during forming. Highly-loaded suspensions (>40 vol.%) are desired because all formed ceramic bodies have to be sintered to remove pores. Finally, using aqueous-based suspensions reduces any detrimental effect on the environment and tooling. The preparation of highly-loaded suspensions requires the development of a suitable dispersant through which particle-particle interactions are controlled. However, silicon nitride is difficult to stabilize in water due to complex surface and solution chemistry. In this study, aqueous silicon nitride suspensions up to 45 vol.% solids loading were

  3. Electrostratic stabilization of suspensions in non-aqueous media

    NARCIS (Netherlands)

    Hoeven, van der P.C.

    1991-01-01

    Concentrated suspensions of detergent powder solids in a liquid nonionic surfactant are considered for practical application as liquid detergent products. If no precautions are taken, upon storage the viscosity of such suspensions increases and the pourability drops because the suspensions are

  4. Size, velocity, and concentration in suspension measurements of spherical droplets and cylindrical jets.

    Science.gov (United States)

    Onofri, F; Bergougnoux, L; Firpo, J L; Misguich-Ripault, J

    1999-07-20

    The principle of an optical technique for simultaneous velocity, size, and concentration in suspension measurements of spherical droplets and cylindrical jets is proposed. This technique is based on phase Doppler anemometry working in the dual burst technique configuration. The particle size and velocity are deduced from the reflected signal phase and frequency, whereas the amplitude ratio between the refracted and the reflected signals is used for measuring the concentration of small scatterers inside the particles. Numerical simulations, based on geometrical optics and a Monte Carlo model, and an experimental validation test on cylindrical jets made of various suspensions, are used to validate the principle of the proposed technique. It is believed that this new technique could be useful in investigating processes in which liquid suspensions are sprayed for surface coating, drying, or combustion applications.

  5. Submerged cutting characteristics of abrasive suspension jet

    International Nuclear Information System (INIS)

    Shimizu, Seiji; Peng, Guoyi; Oguma, Yasuyuki; Nishikata, Hiroki

    2015-01-01

    An abrasive suspension jet (ASJ) formed by propelling abrasive suspension through a nozzle has a greater cutting capability than the conventional abrasive water jet. However the cutting capability of submerged ASJs decreases drastically with increasing the standoff distance and the pressure around the jet. A sheathed nozzle nozzle with ventilation for ASJs has been developed as a mean of extending the effective stand-off distance and improving the cutting capabilities under submerged condition. In the present investigation, cutting tests by ASJs in air and under submerged condition are conducted with specimens of aluminum alloy. Air coated ASJs are formed by using a sheathed nozzle with ventilation. The relative cutting depth is defined as the cutting depth is arranged effectually by the cavitation number based on the cavity pressure measured at the sheath. (author)

  6. 48 CFR 9.407-2 - Causes for suspension.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Causes for suspension. 9... relating to the submission of offers; (3) Commission of embezzlement, theft, forgery, bribery... laws, or receiving stolen property; or (4) Violations of the Drug-Free Workplace Act of 1988 (Public...

  7. Cimetidine Pharmacodynamics and Pharmacokinetics in Healthy Subjects: A Comparison of Tablets and Suspension

    Directory of Open Access Journals (Sweden)

    ABR Thomson

    1994-01-01

    Full Text Available The objective of this study was to compare the effect of cimetidine 200 mg tablet with that of cimetidine suspension (200 mg/10 mL, a 20 mL suspension of 800 mg magnesium hydroxide and 912 mg aluminum hydroxide, and matching placebo on intragastric pH of healthy volunteers. There were 13 males and seven females, mean age 23 years (range 20 to 32 and mean weight 72 kg (range 55 to 89. The intragastric pH of each subject was measured over 6 h starting immediately before dosing on each of five study days. Cimetidine plasma levels were measured for 6 h after dosing on each of the cimetidine study days. Cimetidine tablet and suspension were superior to placebo tablet or suspension or to the magnesium hydroxide/aluminum hydroxide suspension in the area under the pH time curve from 0 to 6 h, percentage time pH of at least 3.5, change from pretreatment pH area under the pH time curve (0 to 6 h and maximum increase in pH. Mean plasma cimetidine levels were significantly and positively correlated to mean intragastric pH for both cimetidine tablets and cimetidine suspension. Comparing cimetidine concentration (Cmax and lower percentage time plasma cimetidine concentration was at least 0.5 μg/mL (the minimum therapeutic level. These pharmacokinetic variations between cimetidine suspension and tablets may have partially explained the pharmacodynamic differences of the lower area under the pH time curve (0 to 6 h. The results indicate that both cimetidine tablets and cimetidine suspension significantly increase intragastric pH relative to the magnesium hydroxide/aluminum hydroxide suspension, placebo tablets or placebo suspension. Based on the assumption that elevation of intragastric pH is an important factor for alleviation of the symptoms and for the healing of peptic disorders, the results of this study suggest that both cimetidine tablets and cimetidine suspension should be effective treatment.

  8. Rheological properties of ceramic nanopowders in aqueous and nonaqueous suspensions

    International Nuclear Information System (INIS)

    Tomaszewski, H.; Loiko, E.M.

    2003-01-01

    The potential for ceramic nanocomposites to offer significantly enhanced mechanical properties is generally known since the first work of Niihara published in 1991. However achieving these properties needs carefully done colloidal processing, because ceramic nanopowders are naturally prone to agglomeration. The work presented here is concerned with the processing of zirconia/alumina nanocomposites via aqueous and alumina silicon carbide nanocomposites via nonaqueous colloidal route. The effect of pH of aqueous alumina and zirconia suspensions on properties of suspension and centrifuged green bodies was studied. A correlation between surface electric charge of grains (zeta potential)and agglomerate size, viscosity of suspension and porosity of green compacts was found. In the case of nonaqueous route alumina and silicon carbide suspensions in iso-propanol were investigated. Electrostatic surface charge of grains was changed by addition of chloroacetic acid and determined indirectly by the mass of powder deposited on electrode during electrophoresis. Different behaviour of SiC nanopowder than of alumina was observed and mechanism of charge creation is proposed on the base of DLVO theory. The effect of grain charge on preventing agglomeration on the silicon carbide powder is presented on micrographs of sintered nanocomposites. (author)

  9. Dispersion of nanoparticulate suspensions using self-assembled surfactant aggregates

    Science.gov (United States)

    Singh, Pankaj Kumar

    The dispersion of particles is critical for several industrial applications such as paints, inks, coatings, and cosmetics. Several emerging applications such as abrasives for precision polishing, and drug delivery systems are increasingly relying on nanoparticulates to achieve the desired performance. In the case of nanoparticles, the dispersion becomes more challenging because of the lack of fundamental understanding of dispersant adsorption and interparticle force prediction. Additionally, many of these processes use severe processing environments such as high normal forces (>100 mN/m), high shear forces (>10,000 s -1), and high ionic strengths (>0.1 M). Under such processing conditions, traditionally used dispersants based on electrostatics, and steric force repulsion mechanism may not be adequate. Hence, the development of optimally performing dispersants requires a fundamental understanding of the dispersion mechanism at the atomic/molecular scale. This study explores the use of self-assembled surfactant aggregates at the solid-liquid interface for dispersing nanoparticles in severe processing environments. Surfactant molecules can provide a feasible alternative to polymeric or inorganic dispersants for stabilizing ultrafine particles. The barrier to aggregation in the presence of surfactant molecules was measured using atomic force microscopy. The barrier heights correlated to suspension stability. To understand the mechanism for nanoparticulate suspension stability in the presence of surfactant films, the interface was characterized using zeta potential, contact angle, adsorption, and FT-IR (adsorbed surfactant film structure measurements). The effect of solution conditions such as pH and ionic strength on the suspension stability, and the self-assembled surfactant films was also investigated. It was determined that a transition from a random to an ordered orientation of the surfactant molecules at the interface was responsible for stability of

  10. Development of an optimized tetracycline-inducible expression system to increase the accumulation of interleukin-10 in tobacco BY-2 suspension cells.

    Science.gov (United States)

    Bortesi, Luisa; Rademacher, Thomas; Schiermeyer, Andreas; Schuster, Flora; Pezzotti, Mario; Schillberg, Stefan

    2012-07-11

    Plant cell suspension cultures can be used for the production of valuable pharmaceutical and industrial proteins. When the recombinant protein is secreted into the culture medium, restricting expression to a defined growth phase can improve both the quality and quantity of the recovered product by minimizing proteolytic activity. Temporal restriction is also useful for recombinant proteins whose constitutive expression affects cell growth and viability, such as viral interleukin-10 (vIL-10). We have developed a novel, tetracycline-inducible system suitable for tobacco BY-2 suspension cells which increases the yields of vIL-10. The new system is based on a binary vector that is easier to handle than conventional vectors, contains an enhanced inducible promoter and 5'-UTR to improve yields, and incorporates a constitutively-expressed visible marker gene to allow the rapid and straightforward selection of the most promising transformed clones. Stable transformation of BY-2 cells with this vector, without extensive optimization of the induction conditions, led to a 3.5 fold increase in vIL-10 levels compared to constitutive expression in the same host. We have developed an effective and straightforward molecular farming platform technology that improves both the quality and the quantity of recombinant proteins produced in plant cells, particularly those whose constitutive expression has a negative impact on plant growth and development. Although we tested the platform using vIL-10 produced in BY-2 cells, it can be applied to other host/product combinations and is also useful for basic research requiring strictly controlled transgene expression.

  11. Efficient Secretion of Recombinant Proteins from Rice Suspension-Cultured Cells Modulated by the Choice of Signal Peptide.

    Science.gov (United States)

    Huang, Li-Fen; Tan, Chia-Chun; Yeh, Ju-Fang; Liu, Hsin-Yi; Liu, Yu-Kuo; Ho, Shin-Lon; Lu, Chung-An

    2015-01-01

    Plant-based expression systems have emerged as a competitive platform in the large-scale production of recombinant proteins. By adding a signal peptide, αAmy3sp, the desired recombinant proteins can be secreted outside transgenic rice cells, making them easy to harvest. In this work, to improve the secretion efficiency of recombinant proteins in rice expression systems, various signal peptides including αAmy3sp, CIN1sp, and 33KDsp have been fused to the N-terminus of green fluorescent protein (GFP) and introduced into rice cells to explore the efficiency of secretion of foreign proteins. 33KDsp had better efficiency than αAmy3sp and CIN1sp for the secretion of GFP from calli and suspension-cultured cells. 33KDsp was further applied for the secretion of mouse granulocyte-macrophage colony-stimulating factor (mGM-CSF) from transgenic rice suspension-cultured cells; approximately 76%-92% of total rice-derived mGM-CSF (rmGM-CSF) was detected in the culture medium. The rmGM-CSF was bioactive and could stimulate the proliferation of a murine myeloblastic leukemia cell line, NSF-60. The extracellular yield of rmGM-CSF reached 31.7 mg/L. Our study indicates that 33KDsp is better at promoting the secretion of recombinant proteins in rice suspension-cultured cell systems than the commonly used αAmy3sp.

  12. Computational Analysis of Static and Dynamic Behaviour of Magnetic Suspensions and Magnetic Bearings

    Science.gov (United States)

    Britcher, Colin P. (Editor); Groom, Nelson J.

    1996-01-01

    Static modelling of magnetic bearings is often carried out using magnetic circuit theory. This theory cannot easily include nonlinear effects such as magnetic saturation or the fringing of flux in air-gaps. Modern computational tools are able to accurately model complex magnetic bearing geometries, provided some care is exercised. In magnetic suspension applications, the magnetic fields are highly three-dimensional and require computational tools for the solution of most problems of interest. The dynamics of a magnetic bearing or magnetic suspension system can be strongly affected by eddy currents. Eddy currents are present whenever a time-varying magnetic flux penetrates a conducting medium. The direction of flow of the eddy current is such as to reduce the rate-of-change of flux. Analytic solutions for eddy currents are available for some simplified geometries, but complex geometries must be solved by computation. It is only in recent years that such computations have been considered truly practical. At NASA Langley Research Center, state-of-the-art finite-element computer codes, 'OPERA', 'TOSCA' and 'ELEKTRA' have recently been installed and applied to the magnetostatic and eddy current problems. This paper reviews results of theoretical analyses which suggest general forms of mathematical models for eddy currents, together with computational results. A simplified circuit-based eddy current model proposed appears to predict the observed trends in the case of large eddy current circuits in conducting non-magnetic material. A much more difficult case is seen to be that of eddy currents in magnetic material, or in non-magnetic material at higher frequencies, due to the lower skin depths. Even here, the dissipative behavior has been shown to yield at least somewhat to linear modelling. Magnetostatic and eddy current computations have been carried out relating to the Annular Suspension and Pointing System, a prototype for a space payload pointing and vibration

  13. Dispersion of phyllosilicates in aqueous suspensions: role of the nature and amount of surfactant.

    Science.gov (United States)

    Houta, Nadia; Lecomte-Nana, Gisèle-Laure; Tessier-Doyen, Nicolas; Peyratout, Claire

    2014-07-01

    The present work aims at investigating the effect of pH values and additives on the dispersion of two 1:1 dioctahedral phyllosilicates in the presence of water. Two model clays are used for this purpose, BIP kaolin and NZCC halloysite, presenting the same surface chemistry but different morphologies. The effect of sodium hexametaphosphate, sodium silicate and sodium carbonate is discussed. Kaolin and halloysite powders were first characterized using X-ray diffraction, thermogravimetric analysis and scanning electron microscopy. Subsequently, suspensions containing 8 mass% of each clay were prepared with or without additives. Experimental measurements regarding the pH values, the zeta potential and the rheological behavior were performed to determine the most suitable additive. Results show that the conformation of halloysite particles changes regarding pH values of suspensions and is strongly related to the surface charges of these particles. At their natural pH values, halloysite and kaolin suspensions exhibit zeta potentials equal to -50 and -20 mV respectively. This trend indicates that halloysite-based suspensions are well dispersed compared to kaolin-based suspensions. Sodium hexametaphosphate is the most suitable dispersant for both clays. The rheological characterization regarding further applications in casting process indicates a shear-thinning behavior for all studied compositions. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Measurement of the effective refractive index of a turbid colloidal suspension using light refraction

    International Nuclear Information System (INIS)

    Reyes-Coronado, A; Garcia-Valenzuela, A; Sanchez-Perez, C; Barrera, R G

    2005-01-01

    We propose and analyse a simple method to measure simultaneously the real and imaginary parts of the effective refractive index of a turbid suspension of particles. The method is based on measurements of the angle of refraction and transmittance of a laser beam that traverses a hollow glass prism filled with a colloidal suspension. We provide a comprehensive assessment of the method. It can offer high sensitivity while still being simple to interpret. We present results of experiments using an optically turbid suspension of polystyrene particles and compare them with theoretical predictions. We also report experimental evidence showing that the refractive behaviour of the diffuse component of light coming from a suspension depends on the volume fraction of the colloidal particles

  15. Ensemble-average versus suspension-scale Cauchy continuum-mechanical definitions of stress in polarized suspensions: Global homogenization of a dilute suspension of dipolar spherical particles

    International Nuclear Information System (INIS)

    Almog, Y.; Brenner, H.

    1999-01-01

    The macroscale rheological properties of a dilute suspension exposed to a uniform external field and composed of identical, rigid, inhomogeneous, dipolar, spherical particles dispersed in an incompressible Newtonian fluid and possessing the same mean density as the latter fluid are derived from knowledge of its microscale properties by applying a global ensemble-averaging technique. Each dipole, which is permanently embedded in the particle, is assumed to be generated by the presence of an inhomogeneous external body-force field in the particle interior resulting from the action of the uniform external field on an inhomogeneous distribution of interior matter. It is shown that although the ensemble-average stress tensor is symmetric, the suspension nevertheless behaves macroscopically as if it possessed an asymmetric stress tensor. This seeming contradiction can be traced to the fact that the average body force acting on the contents of any arbitrarily drawn volume lying in the interior of the suspension does not vanish despite the fact that each particle is 'neutrally buoyant'. That this force is not zero stems from the fact that some particles necessarily straddle the closed surface bounding that volume, and that the distribution of external body forces over the interiors of these particles is nonuniform. As such, that portion of the spherical particle lying outside of the surface enclosing the domain exerts a force on the remaining portion of the sphere lying within that domain. We then demonstrate that the natural macroscopic model, which is derived by equating the divergence of the suspension-scale stress appearing in that model to the ensemble-average external body-force field, and which predicts a symmetric stress tensor, is macroscopically deficient with respect to the more intuitive asymmetric stress model usually proposed by continuum mechanicians for such a suspension. It is shown that the latter, continuum-mechanical model recovers all the physically

  16. Experimental data and theoretical predictions for the rate of electrophoretic clarification of colloidal suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, T.J.; Davis, E.J.

    2000-05-01

    An experimental and theoretical investigation of the electrophoretic clarification rate of colloidal suspensions was conducted. The suspensions included a coal-washing effluent and a model system of TiO{sub 2} particles. A parametric study of TiO{sub 2} suspensions was performed to validate and analysis of the electrophoretic motion of the clarification front formed between a clear zone and the suspension. To measure the electric field strength needed in the prediction of the location of the front, a moveable probe and salt bridge were connected to a reference electrode. Using the measured electric field strengths, it was found that the numerical solution to the unit cell electrophoresis model agrees with the measured clarification rates. For suspensions with moderately thick electric double layers and high particle volume fractions the deviations from classical Smoluchowski theory are substantial, and the numerical analysis is in somewhat better agreement with the data than a prior solution of the problem. The numerical model reduces to the predictions of previous theories as the thickness of the electric double layer decreases, and it is in good agreement with the clarification rate measured for a coal-washing effluent suspension with thin electric double layers.

  17. Fracture in Kaolinite clay suspensions

    Science.gov (United States)

    Kosgodagan Acharige, Sebastien; Jerolmack, Douglas J.; Arratia, Paulo E.

    2017-11-01

    Clay minerals are involved in many natural (landslides, river channels) and industrial processes (ceramics, cosmetics, oil recovery). They are plate shaped charged colloids and exhibit different flow properties than simpler colloids when suspended in a liquid such as thixotropy and shear-banding. kaolinite platelets are non-swelling, meaning that the stacks formed by the platelets do not have water layers, and thus the suspension does not have a sol-gel transition. However, it has been shown that kaolinite suspensions possesses a non-zero yield stress even at low concentrations, indicating that the particles arrange themselves in a structure through attractive interactions. Here, we experimentally investigate the sedimentation of kaolinite suspensions in a Hele-Shaw cell. The sedimentation of these dilute suspensions can display solid behavior like fracture, revealed in cross-polarized light, which is linked to the failure of the weakly-bonded structure (typical yield stress 10-2 Pa). By changing the interaction potential of the particles (by sonication or introducing salts), we show through these sedimentation experiments, how the fracture pattern can be avoided. Research was sponsored by the Army Research Laboratory and was accomplished under Grant Number 569074.

  18. Electrorheological suspensions of laponite in oil: rheometry studies.

    Science.gov (United States)

    Parmar, K P S; Méheust, Y; Schjelderupsen, Børge; Fossum, J O

    2008-03-04

    We have studied the effect of an external direct current (DC) electric field ( approximately 1 kV/mm) on the rheological properties of colloidal suspensions consisting of aggregates of laponite particles in a silicone oil. Microscopy observations show that, under application of an electric field greater than a triggering electric field Ec approximately 0.6 kV/mm, laponite aggregates assemble into chain- and/or columnlike structures in the oil. Without an applied electric field, the steady-state shear behavior of such suspensions is Newtonian-like. Under application of an electric field larger than Ec, it changes dramatically as a result of the changes in the microstructure: a significant yield stress is measured, and under continuous shear the fluid is shear-thinning. The rheological properties, in particular the dynamic and static shear stress, were studied as a function of particle volume fraction for various strengths (including null) of the applied electric field. The flow curves at constant shear rate can be scaled with respect to both the particle fraction and electric field strength onto a master curve. This scaling is consistent with simple scaling arguments. The shape of the master curve accounts for the system's complexity; it approaches a standard power-law model at high Mason numbers. Both dynamic and static yield stresses are observed to depend on the particle fraction Phi and electric field E as PhibetaEalpha, with alpha approximately 1.85 and beta approximately 1 and 1.70 for the dynamic and static yield stresses, respectively. The yield stress was also determined as the critical stress at which there occurs a bifurcation in the rheological behavior of suspensions that are submitted to a constant shear stress; a scaling law with alpha approximately 1.84 and beta approximately 1.70 was obtained. The effectiveness of the latter technique confirms that such electrorheological (ER) fluids can be studied in the framework of thixotropic fluids. The method

  19. Poisson-Boltzmann theory of charged colloids: limits of the cell model for salty suspensions

    International Nuclear Information System (INIS)

    Denton, A R

    2010-01-01

    Thermodynamic properties of charge-stabilized colloidal suspensions and polyelectrolyte solutions are commonly modelled by implementing the mean-field Poisson-Boltzmann (PB) theory within a cell model. This approach models a bulk system by a single macroion, together with counterions and salt ions, confined to a symmetrically shaped, electroneutral cell. While easing numerical solution of the nonlinear PB equation, the cell model neglects microion-induced interactions and correlations between macroions, precluding modelling of macroion ordering phenomena. An alternative approach, which avoids the artificial constraints of cell geometry, exploits the mapping of a macroion-microion mixture onto a one-component model of pseudo-macroions governed by effective interparticle interactions. In practice, effective-interaction models are usually based on linear-screening approximations, which can accurately describe strong nonlinear screening only by incorporating an effective (renormalized) macroion charge. Combining charge renormalization and linearized PB theories, in both the cell model and an effective-interaction (cell-free) model, we compute osmotic pressures of highly charged colloids and monovalent microions, in Donnan equilibrium with a salt reservoir, over a range of concentrations. By comparing predictions with primitive model simulation data for salt-free suspensions, and with predictions from nonlinear PB theory for salty suspensions, we chart the limits of both the cell model and linear-screening approximations in modelling bulk thermodynamic properties. Up to moderately strong electrostatic couplings, the cell model proves accurate for predicting osmotic pressures of deionized (counterion-dominated) suspensions. With increasing salt concentration, however, the relative contribution of macroion interactions to the osmotic pressure grows, leading predictions from the cell and effective-interaction models to deviate. No evidence is found for a liquid

  20. 36 CFR 296.10 - Suspension and revocation of permits.

    Science.gov (United States)

    2010-07-01

    ... AGRICULTURE PROTECTION OF ARCHAEOLOGICAL RESOURCES: UNIFORM REGULATIONS § 296.10 Suspension and revocation of... correct the situation which led to suspension of the permit. (b) Suspension or revocation for management...

  1. Analysis Of The Method Of Predictive Control Applicable To Active Magnetic Suspension Systems Of Aircraft Engines

    Directory of Open Access Journals (Sweden)

    Kurnyta-Mazurek Paulina

    2015-12-01

    Full Text Available Conventional controllers are usually synthesized on the basis of already known parameters associated with the model developed for the object to be controlled. However, sometimes it proves extremely difficult or even infeasible to find out these parameters, in particular when they subject to changes during the exploitation lifetime. If so, much more sophisticated control methods have to be applied, e.g. the method of predictive control. Thus, the paper deals with application of the predictive control approach to follow-up tracking of an active magnetic suspension where the mathematical and simulation models for such a control system are disclosed with preliminary results from simulation investigations of the control system in question.

  2. Phosphate Suspension Chromium (III) radiolabelled with 32P and 90Y

    International Nuclear Information System (INIS)

    Cruz Arencibia, Jorge; Turiño Pérez, David; Cruz Morales, Amed; Morín Zorrilla, José; Taylor Delgado, Tamara; García Rodríguez, Enrique; Baganet Cobas, Aymara

    2016-01-01

    Chronic synovitis is a manifestation common joint of rheumatoid arthritis, hemophilia and other systemic diseases. The modalities of treatment of this complication radiosynoviorthesis stands out for its good response, ease of implementation and lower total cost. In the United States, Europe and some countries in Latin America they are used to this different radioactive colloids and suspensions. In Cuba it was developed and is approved suspension Chromic Phosphate 32 P-labeled. At work the consistency of the production process of this suspension is examined. As a result of the evaluation was found that the suspension is characterized by a radiochemical purity of 94 ± 1% and particle size predominantly of 91 ± 3 between 0.2-10 microns. The results achieved in regular production and application to patients with rheumatic diseases and hemophiliacs, with follow-up to one year prove their efficacy and safety, the latter associated with low leakage articular detected and the absence of adverse reactions. Also at work the results achieved in the development of a technology for the production of suspension Phosphate Chromium (III) labeled with 90 Y, similarly to existing 32 P composition is exposed, and properties even more favorable, in particular radiochemical purity of 97%, favoring the registration of a radiopharmaceutical with better technical and economic characteristics, which must ensures the use of this form of treatment in the country. (author)

  3. 39 CFR 320.9 - Revocation or amendment of suspensions.

    Science.gov (United States)

    2010-07-01

    ... SUSPENSION OF THE PRIVATE EXPRESS STATUTES § 320.9 Revocation or amendment of suspensions. These suspensions... of operations (in dollar or volume terms, whichever is larger) lower than that antedating the...

  4. A novel magnetic suspension cum linear actuator system for satellite cryo coolers

    International Nuclear Information System (INIS)

    Sivadasan, K.K.

    1994-01-01

    Stirling cycle cryogenic coolers have been widely used for device cooling in satellites. Various types of magnetic bearings and linear actuators find application in such systems. The most widely used configurations have two-axis-radially-active suspension stations placed at either ends of a reciprocating shaft in the compression and expansion sections. Separate or integral liner motors are provided in each section for axial shaft movement. It may be noted that such configurations are rather complicated and less reliable because of the presence of numerous electro-mechanical components, sensors and electronic servo channels. In this paper, a simple and reliable scheme is suggested which axially stabilizes and linearly perturbs the piston so that the need for a separate motor for axial actuation can be totally dispensed with. The piston is radially supported by passive repulsive bearings. In the axial direction, a servo actuator ''balances'' the piston and also actuates it bi-directionally. Implemented of this ''bearing cum motor theme,'' reduces the number of electromechanical and electronic components required to operate the system and hence minimizes the chances of system failure. Apart from this, the system's power consumption is reduced and efficiency is improved as electrical heating losses caused by quiescent-operating currents are removed and electromagnetic losses on the moving parts are minimized. The necessary system parameters have been derived using finite element analysis techniques. Finally, the proposed design is validated by computer-aided system simulation

  5. Ecoulement et mise en structure de suspensions macroscopiques

    Science.gov (United States)

    Petit, L.

    In this review, we report the various experimental studies performed on suspensions of solid particules in liquids, and concerning the rheological behaviour of such systems and the ordering of particules under the applied velocity fields. The number of materials which are flowing suspensions (reagents in chemical engineering, paints while spreading, blood flow, muds in oil reservoir) gave rise to a number of experimental studies, especially in the last twenty years. The results show a wide variety of behaviour, even for systems of intermediate concentration. In addition, even for identical systems, the results depend of the type of flow. Then, it is clear that, in addition of the standard parameters which are to be taken into account, it is necessary to consider the type of flow the suspension is submitted to. The flow influences the spatial distribution of the particules, leading to their ordering or migration. These ordering or motions influence the flow, and then, the rheological behaviour of the whole system. So, there is a feedback mechanism from the ordering to the flow, which explains the experimental observations. Nous reportons dans cette revue les différentes études expérimentales réalisées sur les suspensions de particules solides dans un liquide et qui concernent le comportement rhéologique de ces systèmes ainsi que les mouvements des particules sous l'effet des champs de vitesse imposés. Ces mouvements peuvent conduire soit à des mises en structure, ou encore à des migrations des particules. L'importance du nombre de matériaux qui se présentent sous forme de suspension et qui sont mis en écoulement (réactif en génie chimique, peintures lors de leur mise en place, écoulement sanguin, boues dans les forages pétroliers,...) a motivé un grand nombre de travaux expérimentaux plus fondamentaux sur le sujet, particulièrement dans les vingt dernières années. Les résultats correspondants montrent une très grande diversité des

  6. Behaviour of humic-bentonite aggregates in diluted suspensions ...

    African Journals Online (AJOL)

    Formation and disaggregation of micron-size aggregates in a diluted suspension made up of HSs and bentonite (B) were studied by tracing distribution of aggregate sizes and their counts in freshly prepared and aged suspensions, and at high (10 000) and low (1.0) [HS]/[B] ratios. Diluted HSB suspensions are unstable ...

  7. Yield stress of alumina-zirconia suspensions

    International Nuclear Information System (INIS)

    Ramakrishnan, V.; Pradip; Malghan, S.G.

    1996-01-01

    The yield stress of concentrated suspensions of alumina, zirconia, and mixed alumina-zirconia powders was measured by the vane technique as a function of solids loading, relative amounts of alumina and zirconia, and pH. At the isoelectric point (IEP), the yield stress varied as the fourth power of the solids loading. The relative ratio of alumina and zirconia particles was important in determining the yield stress of the suspension at the IEP. The yield stress of single and mixed suspensions showed a marked variation with pH. The maximum value occurred at or near the IEP of the suspension. The effect of electrical double-layer forces on the yield stress can be described on the basis of the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. A normalized yield stress--that is, the ratio of the yield stress at a given pH to the yield stress at the IEP predicted by this model--showed good correlation with experimental data

  8. Clay particles as binder for earth buildings materials: a fresh look into rheology of dense clay suspensions

    Directory of Open Access Journals (Sweden)

    Landrou Gnanli

    2017-01-01

    Full Text Available In the ceramic industry and in many sectors, clay minerals are widely used. In earthen construction technique, clay plays a crucial role in the processing. The purpose of this research is to understand and modify the clay properties in earth material to propose an innovative strategy to develop a castable earth-based material. To do so, we focused on the modification of clay properties at fresh state with inorganic additives. As the rheological behaviour of clays is controlled by their surface charge, the addition of phosphate anion allows discussing deep the rheology of concentrated clay suspensions. We highlighted the thixotropic and shear thickening behaviour of a dispersed kaolinite clay suspensions. Indeed, by adding sodium hexametaphosphate the workability of clay paste increases and the behaviour is stable during time after a certain shear is applied. Moreover, we stress that the aging and the shift in critical strain in clay system are due to the re-arrangement of clay suspension and a decrease of deformation during time. The understanding of both effect: thixotropy and aging are crucial for better processing of clay-based material and for self-compacting clay concrete. Yet, studies need to pursue to better understand the mechanism.

  9. Vaginal vault suspension during hysterectomy for benign indications

    DEFF Research Database (Denmark)

    Bonde, Lisbeth; Noer, Mette Calundann; Møller, Lars Alling

    2017-01-01

    Introduction and hypothesis: Several suspension methods are used to try to prevent pelvic organ prolapse (POP) after hysterectomy. We aimed to evaluate agreement on terminology and surgical procedure of these methods. Methods: We randomly chose 532 medical records of women with a history......: Regarding medical records, agreement on terminology was good among patients undergoing pooled suspension in cases of hysterectomy via the abdominal and vaginal route (agreement 78.7, 92.3%). Regarding videos, agreement on surgical procedure was good among pooled suspension patients in cases of hysterectomy...... via the abdominal, laparoscopic, and vaginal routes (agreement 88.9, 97.8, 100%). Agreement on individual suspension methods differed regarding both medical records (agreement 0–90.1%) and videos (agreement 0–100%). Conclusions: Agreement on terminology and surgical procedure regarding suspension...

  10. Microstructural Dynamics and Rheology of Suspensions of Rigid Fibers

    Science.gov (United States)

    Butler, Jason E.; Snook, Braden

    2018-01-01

    The dynamics and rheology of suspensions of rigid, non-Brownian fibers in Newtonian fluids are reviewed. Experiments, theories, and computer simulations are considered, with an emphasis on suspensions at semidilute and concentrated conditions. In these suspensions, interactions between the particles strongly influence the microstructure and rheological properties of the suspension. The interactions can arise from hydrodynamic disturbances, giving multibody interactions at long ranges and pairwise lubrication forces over short distances. For concentrated suspensions, additional interactions due to excluded volume (contacts) and adhesive forces are addressed. The relative importance of the various interactions as a function of fiber concentration is assessed.

  11. Discontinuous Shear Thickening and Dilatancy: Frictional Effects in Viscous Suspensions

    Science.gov (United States)

    Morris, Jeffrey

    2015-03-01

    Shear thickening in concentrated suspensions has been well-known for quite a long time, yet a firm consensus on the basis for very abrupt or ``discontinuous'' shear thickening (DST) seen in suspensions of large solid fraction, ϕ, has not been reached. This work addresses the DST phenomenon, and proposes a simulation method based in the Stokesian Dynamics algorithm to explore the role of various forces between the particles, including hydrodynamic, conservative potential, and frictional interactions. This work shows that allowance for friction between spherical particles suspended in a viscous liquid causes a significant reduction in the jamming solid fraction of the mixture, ϕmax, taken as the maximum fraction at which the suspension will flow. A consequence of this is a shifting of the singularity in the effective viscosity, η, to smaller ϕmax, and the frictional suspension has a larger viscosity than does the frictionless suspension of the same solid fraction, as is clear from the standard empirical modeling of η (ϕ) =(1 - ϕ /ϕmax) - α , α ~ 2 . When a counterbalancing repulsive force between the particles, representative for example of charge-induced repulsion, is incorporated in the dynamics, the mixture undergoes a transition from frictionless to frictional interactions, and from low to high effective viscosity, at a critical shear rate. Comparison with experimental data shows remarkable agreement in the features of DST captured by the method. The basic algorithm and results of both rate-controlled and stress-controlled simulations will be presented. Like the shear stress, the magnitude of the normal stress exerted by the suspended particles also increases abruptly at the critical shear rate, consistent with the long-standing notion that dilatancy and shear-thickening are synonymous. We will show that considering all shear thickening materials as dilatant is a misconception, but demonstrate the validity of the connection of dilatancy with DST in

  12. Pitched Blade Turbine Efficiency at Particle Suspension

    Directory of Open Access Journals (Sweden)

    D. Ceres

    2010-01-01

    Full Text Available Mixing suspensions is a very important hydraulic operation. The pitched six-blade turbine is a widely-used axial-flow impeller. This paper deals with effect relative impeller size and particle content on theefficiency of a pitched six-blade turbine at particle suspension. Two pitched six-blade turbines were used in model measurements of just suspension impeller speed. The ratios of the vessel to agitator diameter D/d were 3 and 4.5. The measurements were carried out in a dish-bottomed vessel 300 mm in diameter. The just suspension impeller speeds were measured using an electrochemical method, and were checked visually. A 2.5 % NaCl water solution was used as the liquid phase, and glass particles with four equivalent diameters between 0.18 and 0.89 mmand volumetric concentration from 2.5 % to 40% were usedasthesolid phase. The criterion values πs=Po√Fr'3(d/D7 were calculated from the particle suspension and power consumption measurements. The dependencies of πs on particle content cv show that larger agitators are more efficient for higher particle content.

  13. Metastable and unstable cellular solidification of colloidal suspensions

    Science.gov (United States)

    Deville, Sylvain; Maire, Eric; Bernard-Granger, Guillaume; Lasalle, Audrey; Bogner, Agnès; Gauthier, Catherine; Leloup, Jérôme; Guizard, Christian

    2009-12-01

    Colloidal particles are often seen as big atoms that can be directly observed in real space. They are therefore becoming increasingly important as model systems to study processes of interest in condensed-matter physics such as melting, freezing and glass transitions. The solidification of colloidal suspensions has long been a puzzling phenomenon with many unexplained features. Here, we demonstrate and rationalize the existence of instability and metastability domains in cellular solidification of colloidal suspensions, by direct in situ high-resolution X-ray radiography and tomography observations. We explain such interface instabilities by a partial Brownian diffusion of the particles leading to constitutional supercooling situations. Processing under unstable conditions leads to localized and global kinetic instabilities of the solid/liquid interface, affecting the crystal morphology and particle redistribution behaviour.

  14. Two-Phase Flow in Packed Columns and Generation of Bubbly Suspensions for Chemical Processing in Space

    Science.gov (United States)

    Motil, Brian J.; Green, R. D.; Nahra, H. K.; Sridhar, K. R.

    2000-01-01

    For long-duration space missions, the life support and In-Situ Resource Utilization (ISRU) systems necessary to lower the mass and volume of consumables carried from Earth will require more sophisticated chemical processing technologies involving gas-liquid two-phase flows. This paper discusses some preliminary two-phase flow work in packed columns and generation of bubbly suspensions, two types of flow systems that can exist in a number of chemical processing devices. The experimental hardware for a co-current flow, packed column operated in two ground-based low gravity facilities (two-second drop tower and KC- 135 low-gravity aircraft) is described. The preliminary results of this experimental work are discussed. The flow regimes observed and the conditions under which these flow regimes occur are compared with the available co-current packed column experimental work performed in normal gravity. For bubbly suspensions, the experimental hardware for generation of uniformly sized bubbles in Couette flow in microgravity conditions is described. Experimental work was performed on a number of bubbler designs, and the capillary bubble tube was found to produce the most consistent size bubbles. Low air flow rates and low Couette flow produce consistent 2-3 mm bubbles, the size of interest for the "Behavior of Rapidly Sheared Bubbly Suspension" flight experiment. Finally the mass transfer implications of these two-phase flows is qualitatively discussed.

  15. The Decision of Dismissal, Suspension, or Discontinuation of Employment of Public/Private School Teachers

    Directory of Open Access Journals (Sweden)

    Jui-Che Wu

    2014-06-01

    Full Text Available There have been controversies over the legal attribute of the decision of dismissal, suspension, or discontinuation of employment of public and private school teachers. The Supreme Administrative Court passed a resolution in July, 2009. In this resolution, the legal relationship between public schools and their teachers was regarded as administrative contracts while the legal attribute of the decision of dismissal, suspension, or discontinuation of employment was categorized into administrative dispositions. Besides, the administrative disposition will not take effect until it obtains approval from the competent educational authorities, and teachers can seek administrative appeal as remedy first, which makes remedy procedure complicated. Therefore, this study first attempts to categorize the legal relationship between the public and private schools and their teachers. Then, the legal attribute of the decision of dismissal, suspension, or discontinuation of employment and the remedy procedure are discussed. It is concluded in this study that the legal relationships between public/private schools and their teachers fall into the categories of administrative/civic contract respectively. Any decision of dismissal, suspension, or discontinuation of employment should be based on this categorization, and the remedy procedure can thus be reduced. Besides teacher’s appeal and re-appeal system being in accordance with Teacher’s Act, the appeal of declaratory judgment on contractual relationship to either the Administrative Court or the Civic Court can also be filed. As a result, the remedy procedure can be simplified to an extent to follow the basic principles stated in the resolution.

  16. Mapping and characterisation of the sorghum cell suspension ...

    African Journals Online (AJOL)

    Here we reported the first secretomic study of sorghum (Sorghum bicolor), a naturally drought tolerant cereal crop. In this study, we used a gel-based proteomic approach in combination with mass spectrometry to separate and identify proteins secreted into the culture medium of sorghum cell suspensions, a first step ...

  17. Adaptive sliding control of non-autonomous active suspension systems with time-varying loadings

    Science.gov (United States)

    Chen, Po-Chang; Huang, An-Chyau

    2005-04-01

    An adaptive sliding controller is proposed in this paper for controlling a non-autonomous quarter-car suspension system with time-varying loadings. The bound of the car-body loading is assumed to be available. Then, the reference coordinate is placed at the static position under the nominal loading so that the system dynamic equation is derived. Due to spring nonlinearities, the system property becomes asymmetric after coordinate transformation. Besides, in practical cases, system parameters are not easy to be obtained precisely for controller design. Therefore, in this paper, system uncertainties are lumped into two unknown time-varying functions. Since the variation bound of one of the unknown functions is not available, conventional adaptive schemes and robust designs are not applicable. To deal with this problem, the function approximation technique is employed to represent the unknown function as a finite combination of basis functions. The Lyapunov direct method can thus be used to find adaptive laws for updating coefficients in the approximating series and to prove stability of the closed-loop system. Since the position and velocity measurements of the unsprung mass are lumped into the unknown function, there is no need to install sensors on the axle and wheel assembly in the actual implementation. Simulation results are presented to show the performance of the proposed strategy.

  18. Experimental data and theoretical predictions of the rate of electrophoretic clarification of colloidal suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, T.J.; Davis, E.J. [University of Washington, Seattle, WA (USA). Dept. of Chemical Engineering

    2000-05-01

    An experimental and theoretical investigation of the electrophoretic clarification rate of colloidal suspensions was conducted. The suspensions included a coal-washing effluent and a model system of TiO{sub 2} particles. A parametric study of TiO{sub 2} suspensions was performed to validate an analysis of the electrophoretic motion of the clarification front formed between a clear zone and the suspension. To measure the electric field strength needed in the prediction of the location of the front, a moveable probe and salt bridge were connected to a reference electrode. Using the measured electric field strength, it was found that the numerical solution to the unit cell electrophoresis model agrees with the measured clarification rates. For suspensions with moderately thick electric double layers and high particle volume fractions the deviations from classical Smoluchowski theory are substantial, and the numerical analysis is in somewhat better agreement with the data than a prior solution of the problem. The numerical model reduces to the predictions of previous theories as the thickness of the electric double layer decreases, and it is in good agreement with the clarification rate measured for a coal-washing effluent suspension with thin electric double layers. 21 refs., 8 figs., 4 tabs.

  19. Development of Prototype HTS Components for Magnetic Suspension Applications

    Science.gov (United States)

    Haldar, P.; Hoehn, J., Jr.; Selvamanickam, V.; Farrell, R. A.; Balachandran, U.; Iyer, A. N.; Peterson, E.; Salazar, K.

    1996-01-01

    We have concentrated on developing prototype lengths of bismuth and thallium based silver sheathed superconductors by the powder-in-tube approach to fabricate high temperature superconducting (HTS) components for magnetic suspension applications. Long lengths of mono and multi filament tapes are presently being fabricated with critical current densities useful for maglev and many other applications. We have recently demonstrated the prototype manufacture of lengths exceeding 1 km of Bi-2223 multi filament conductor. Long lengths of thallium based multi-filament conductor have also been fabricated with practical levels of critical current density and improved field dependence behavior. Test coils and magnets have been built from these lengths and characterized over a range of temperatures and background fields to determine their performance. Work is in progress to develop, fabricate and test HTS windings that will be suitable for magnetic suspension, levitation and other electric power related applications.

  20. Magnetic separation from superparamagnetic particle suspensions

    International Nuclear Information System (INIS)

    Sinha, Ashok; Ganguly, Ranjan; Puri, Ishwar K.

    2009-01-01

    We investigate the magnetophoretic separation of magnetic microparticles from a non-dilute flow in a microfluidic channel and their subsequent field-induced aggregation under the influence of an externally applied magnetic force. This force induces dipolar interactions between the particles that aid in their separation from the flow. Existing analytical models for dilute suspensions cannot be extended to non-dilute suspensions in which interparticle magnetic interactions play an important role. We therefore conduct a parametric investigation of the mechanics of this problem in a microcapillary flow through simulations and experimental visualization. When a magnetic field is applied, the magnetic microparticles form an aggregate on the channel wall that is influenced by the competition between the holding magnetic force and the aggregate-depleting flow shear force. Microparticle collection in the aggregate increases linearly with increasing magnetic field strength and is characterized by distinct buildup and washaway phases. The collected microparticle volume fraction in an aggregate is found to depend on a single dimensional group that depends upon characteristic system parameters.

  1. Submerged cutting characteristics of abrasive suspension jet

    International Nuclear Information System (INIS)

    Shimizu, Seiji; Peng, Guoyi; Oguma, Yasuyuki; Nishikata, Hiroyuki

    2015-01-01

    An abrasive suspension jet (ASJ) formed by propelling abrasive suspension through a nozzle has a greater cutting capability than the conventional abrasive water jet. However the cutting capability of submerged ASJs decreases drastically with increasing the standoff distance and the pressure around the jet. A sheathed nozzle with ventilation for ASJs has been developed as a mean of extending the effective stand-off distance and improving the cutting capabilities under submerged condition. In the present investigation, cutting tests by ASJs in air and under submerged condition are conducted with specimens of aluminum alloy. Air coated ASJs are formed by using a sheathed nozzle with ventilation. The relative cutting depth is defined as the cutting depth under submerged condition divided by the cutting depth in air at the same standoff distance. The relative cutting depth is arranged effectually by the cavitation number based on the cavity pressure measured at the sheath. (author)

  2. Red blood cell (RBC) suspensions in confined microflows: Pressure-flow relationship.

    Science.gov (United States)

    Stauber, Hagit; Waisman, Dan; Korin, Netanel; Sznitman, Josué

    2017-10-01

    Microfluidic-based assays have become increasingly popular to explore microcirculation in vitro. In these experiments, blood is resuspended to a desired haematocrit level in a buffer solution, where frequent choices for preparing RBC suspensions comprise notably Dextran and physiological buffer. Yet, the rational for selecting one buffer versus another is often ill-defined and lacks detailed quantification, including ensuing changes in RBC flow characteristics. Here, we revisit RBC suspensions in microflows and attempt to quantify systematically some of the differences emanating between buffers. We measure bulk flow rate (Q) of RBC suspensions, using PBS- and Dextran-40, as a function of the applied pressure drop (ΔP) for two hematocrits (∼0% and 23%). Two distinct microfluidic designs of varying dimensions are employed: a straight channel larger than and a network array similar to the size of individual RBCs. Using the resulting pressure-flow curves, we extract the equivalent hydrodynamic resistances and estimate the relative viscosities. These efforts are a first step in rigorously quantifying the influence of the 'background' buffer on RBC flows within microfluidic devices and thereby underline the importance of purposefully selecting buffer suspensions for microfluidic in vitro assays. Copyright © 2017. Published by Elsevier Ltd.

  3. Magnetic suspension - Today's marvel, tomorrow's tool

    Science.gov (United States)

    Lawing, Pierce L.

    1989-01-01

    NASA's Langley facility has through constant advocacy of magnetic suspension systems (MSSs) for wind-tunnel model positioning obtained a technology-development status for the requisite large magnets, computers, automatic control techniques, and apparatus configurations, to contemplate the construction of MSSs for large wind tunnels. Attention is presently given to the prospects for MSSs in wind tunnels employing superfluid helium atmospheres to obtain very high Reynolds numbers, where the MSS can yield substantial enhancements of wind tunnel productivity.

  4. 36 CFR 25.3 - Supervision; suspensions.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Supervision; suspensions. 25.3 Section 25.3 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL MILITARY PARKS; LICENSED GUIDE SERVICE REGULATIONS § 25.3 Supervision; suspensions. (a) The guide service will operate under the direction...

  5. Testing of Prototype Magnetic Suspension Cryogenic Transfer Line

    Science.gov (United States)

    Fesmire, J. E.; Augustynowicz, S. D.; Nagy, Z. F.; Sojourner, S. J.; Shu, Q. S.; Cheng, G.; Susta, J. T.

    2006-04-01

    A 6-meter prototype cryogenic transfer line with magnetic suspension was tested for its mechanical and thermal performance at the Cryogenics Test Laboratory of NASA Kennedy Space Center (KSC). A test facility with two cryogenic end-boxes was designed and commissioned for the testing. Suspension mechanisms were verified through a series of tests with liquid nitrogen. The thermal performance of the prototype was determined using the new test apparatus. The tested prototype has incorporated temperature and vacuum pressure data acquisition ports, customized interfaces to cryogenic end-boxes, and instrumentation. All tests were conducted under simulated onsite transfer line working conditions. A static (boiloff rate measurement) testing method was employed to demonstrate the gross heat leak in the tested article. The real-time temperature distribution, vacuum level, levitation distance, and mass flow rate were measured. The main purpose of this paper is to summarize the testing facility design and preparation, test procedure, and primary test results. Special arrangements (such as turning on/off mechanical support units, observing levitation gap, and setting up the flowmeter) in testing of such a magnetically levitated transfer line are also discussed. Preliminary results show that the heat leak reduction of approximately one-third to one-half is achievable through such transfer lines with a magnetic suspension system.

  6. Low-resolution simulations of vesicle suspensions in 2D

    Science.gov (United States)

    Kabacaoğlu, Gökberk; Quaife, Bryan; Biros, George

    2018-03-01

    Vesicle suspensions appear in many biological and industrial applications. These suspensions are characterized by rich and complex dynamics of vesicles due to their interaction with the bulk fluid, and their large deformations and nonlinear elastic properties. Many existing state-of-the-art numerical schemes can resolve such complex vesicle flows. However, even when using provably optimal algorithms, these simulations can be computationally expensive, especially for suspensions with a large number of vesicles. These high computational costs can limit the use of simulations for parameter exploration, optimization, or uncertainty quantification. One way to reduce the cost is to use low-resolution discretizations in space and time. However, it is well-known that simply reducing the resolution results in vesicle collisions, numerical instabilities, and often in erroneous results. In this paper, we investigate the effect of a number of algorithmic empirical fixes (which are commonly used by many groups) in an attempt to make low-resolution simulations more stable and more predictive. Based on our empirical studies for a number of flow configurations, we propose a scheme that attempts to integrate these fixes in a systematic way. This low-resolution scheme is an extension of our previous work [51,53]. Our low-resolution correction algorithms (LRCA) include anti-aliasing and membrane reparametrization for avoiding spurious oscillations in vesicles' membranes, adaptive time stepping and a repulsion force for handling vesicle collisions and, correction of vesicles' area and arc-length for maintaining physical vesicle shapes. We perform a systematic error analysis by comparing the low-resolution simulations of dilute and dense suspensions with their high-fidelity, fully resolved, counterparts. We observe that the LRCA enables both efficient and statistically accurate low-resolution simulations of vesicle suspensions, while it can be 10× to 100× faster.

  7. A theoretical approach to the re-suspension factor

    Directory of Open Access Journals (Sweden)

    Magnoni M.

    2012-04-01

    Full Text Available The atmospheric re-suspension of radionuclides is a well-known phenomenon that consists in the re-injection into the atmosphere of previously deposited radioactivity. The process is driven by the action of wind on surfaces and can act as an additional source of radiation exposure by inhalation, after the deposition has finished. It is thus defined as the re-suspension factor, a parameter K generally considered as a time depending function and defined as the ratio of Ca, the volumetric air activity concentration (Bq m−3 and I0 (Bq m−2, the radioactivity deposition at time zero. The re-suspension factor concept is very useful in radioprotection in order to estimate the inhalation of radionuclides re-suspended from contaminated surfaces when direct atmospheric measurements are lacking or difficult to perform. However, the choice of the proper values of K is usually not a simple task, being quite site-specific and related to the meteorological, géomorphologie and environmental characteristics of the area to be studied. Moreover, several investigations showed clearly that the values of K are a decreasing function of time. For that reason, K values span several orders of magnitude: typical values in the range 10−5–10−10 m−1 are reported in literature for different environmental conditions and time elapsed since the deposition event. The current available models for the re-suspension factor are based on empirical formulas whose parameters are highly site dependent and cannot easily be related to some physical quantity. In this paper a simple physical model for the re-suspension factor is proposed and tested with available environmental radioactivity data (137Cs, collected since 1986 (Chernobyl fallout. The new model not only allows a satisfactory description of the experimental data like even the current empirical models do, but it is also able to connect the K values to quantities with a physical meaning (such as, for example a diffusion

  8. Brownian dynamics simulations of an order-disorder transition in sheared sterically stabilized colloidal suspensions

    International Nuclear Information System (INIS)

    Rigos, A.A.; Wilemski, G.

    1992-01-01

    The shear thinning behavior of a sterically stabilized nonaqueous colloidal suspension was investigated using nonequilibrium Brownian dynamics simulations of systems with 108 and 256 particles. At a volume fraction of 0.4, the suspension is thixotropic: it has a reversible shear thinning transition from a disordered state to an ordered, lamellar state with triangularly packed strings of particles. The time scale for the transition is set by the free particle diffusion constant. For the smaller system, the transition occurs gradually with increasing shear rate. For the larger system, the transition is sharp and discontinuous shear thinning is found. 34 refs., 9 figs., 1 tab

  9. Comparative Studies on the Dissolution Profiles of Oral Ibuprofen Suspension and Commercial Tablets using Biopharmaceutical Classification System Criteria

    Science.gov (United States)

    Rivera-Leyva, J. C.; García-Flores, M.; Valladares-Méndez, A.; Orozco-Castellanos, L. M.; Martínez-Alfaro, M.

    2012-01-01

    In vitro dissolution studies for solid oral dosage forms have recently widened the scope to a variety of special dosage forms such as suspensions. For class II drugs, like Ibuprofen, it is very important to have discriminative methods for different formulations in physiological conditions of the gastrointestinal tract, which will identify different problems that compromise the drug bioavailability. In the present work, two agitation speeds have been performed in order to study ibuprofen suspension dissolution. The suspensions have been characterised relatively to particle size, density and solubility. The dissolution study was conducted using the following media: buffer pH 7.2, pH 6.8, 4.5 and 0.1 M HCl. For quantitative analysis, the UV/Vis spectrophotometry was used because this methodology had been adequately validated. The results show that 50 rpm was the adequate condition to discriminate the dissolution profile. The suspension kinetic release was found to be dependent on pH and was different compared to tablet release profile at the same experimental conditions. The ibuprofen release at pH 1.0 was the slowest. PMID:23626386

  10. Comparison of Two Suspension Arrays for Simultaneous Detection of Five Biothreat Bacterial in Powder Samples

    Directory of Open Access Journals (Sweden)

    Yu Yang

    2012-01-01

    Full Text Available We have developed novel Bio-Plex assays for simultaneous detection of Bacillus anthracis, Yersinia pestis, Brucella spp., Francisella tularensis, and Burkholderia pseudomallei. Universal primers were used to amplify highly conserved region located within the 16S rRNA amplicon, followed by hybridized to pathogen-specific probes for identification of these five organisms. The other assay is based on multiplex PCR to simultaneously amplify five species-specific pathogen identification-targeted regions unique to individual pathogen. Both of the two arrays are validated to be flexible and sensitive for simultaneous detection of bioterrorism bacteria. However, universal primer PCR-based array could not identify Bacillus anthracis, Yersinia pestis, and Brucella spp. at the species level because of the high conservation of 16S rDNA of the same genus. The two suspension arrays can be utilized to detect Bacillus anthracis sterne spore and Yersinia pestis EV76 from mimic “write powder” samples, they also proved that the suspension array system will be valuable tools for diagnosis of bacterial biothreat agents in environmental samples.

  11. Rheological Properties of Aqueous Nanometric Alumina Suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chuanping [Iowa State Univ., Ames, IA (United States)

    2004-01-01

    Colloidal processing is an effective and reliable approach in the fabrication of the advanced ceramic products. Successful colloidal processing of fine ceramic powders requires accurate control of the rheological properties. The accurate control relies on the understanding the influences of various colloidal parameters on the rheological properties. Almost all research done on the rheology paid less attention to the interactions of particle and solvent. However, the interactions of the particles are usually built up through the media in which the particles are suspended. Therefore, interactions of the particle with the media, the adsorbed layers on the particle surface, and chemical and physical properties of media themselves must influence the rheology of the suspension, especially for the dense suspensions containing nanosized particles. Relatively little research work has been reported in this area. This thesis addresses the rheological properties of nanometric alumina aqueous suspensions, and paying more attention to the interactions between particle and solvent, which in turn influence the particle-particle interactions. Dense nanometric alumina aqueous suspensions with low viscosity were achieved by environmentally-benign fructose additives. The rheology of nanometric alumina aqueous suspensions and its variation with the particle volume fraction and concentration of fructose were explored by rheometry. The adsorptions of solute (fructose) and solvent (water) on the nanometric alumina particle surfaces were measured and analyzed by TG/DSC, TOC, and NMR techniques. The mobility of water molecules in the suspensions and its variation with particle volume fractions and fructose additive were determined by the 17O NMR relaxation method. The interactions between the nanometric alumina particles in water and fructose solutions were investigated by AFM. The results indicated that a large number of water layers were physically bound on the particles

  12. Well-dispersed gold nanowire suspension for assembly application

    International Nuclear Information System (INIS)

    Xu Cailing; Zhang Li; Zhang Haoli; Li Hulin

    2005-01-01

    A method for fabricating well-dispersed nanowire suspension has been demonstrated in the paper. Thin gold nanowires were prepared by template synthesis, and then functionalized with sulphonate group-terminated thiols before suspended in different solvents. The degree of aggregation of the obtained suspension was evaluated with transmission electron microscopy (TEM) and UV-vis spectroscopy. It was found that the degree of aggregation was predominated by the solvents, and the best degree of dispersion was obtained when isopropyl alcohol (IPA) was used as the solvent. The gold nanowires from the suspension can be selectively assembled onto chemically patterned substrates. This well-dispersed nanowire suspension is potentially useful for fabricating novel nanodevices

  13. First results from the 'Violin-Mode' tests on an advanced LIGO suspension at MIT

    International Nuclear Information System (INIS)

    Lockerbie, N A; Tokmakov, K V; Carbone, L; Shapiro, B; Bell, A; Strain, K A

    2011-01-01

    This paper describes the first results from 'Violin-Mode' measurements made on the four suspension fibres of a fully suspended 40 kg test mass. These measurements were made at the LIGO lab, Gravitational Wave Observatory test facility, at MIT. Here, an aluminium-alloy (dummy) test mass, simulating an advanced LIGO (Laser Interferometer Gravitational Wave Observatory) test mass/mirror, had been suspended in air from a test suspension by four fused-silica suspension fibres, each measuring 400 μm in diameter x 600 mm long. Violin-Mode measurements were made on these highly tensioned fibres by retrofitting a prototype system of four novel shadow sensors to the test suspension, one per fibre, these sensors having, collectively, a displacement sensitivity of (6.9 ± 1.3) x 10 -11 m (rms) Hz -1/2 , at 500 Hz, over a measuring span of ±0.1 mm. Violin-Mode fundamental resonances were detected in all four fibres: with frequencies ∼ 485 Hz when the test mass was supported lightly from below, and at ∼500 Hz when it was fully suspended. In the latter case the Violin-Mode detection took place whilst the test mass, together with its suspension fibres, was undergoing relatively large-amplitude 'pendulum-mode' motion, at ∼0.6 Hz. This motion was measured to have a peak-peak amplitude at one of the suspension fibres of up to ∼140 μm (35 μm, rms) the shadow sensors each having subsidiary outputs for monitoring such low-frequency, large amplitude, motion. Under fully suspended conditions, a calibrated Violin-Mode 'free-oscillation' amplitude of 430 ± 20 picometres, rms, was measured at 500.875 Hz, in the same suspension fibre which was found to be undergoing, simultaneously, the ∼140 μm peak-peak motion. Over the bandwidth monitored (dc to 3.2 kHz), Violin-Mode harmonics up to the sixth were recorded in an evoked response. It was concluded that the prototype system had demonstrated amply its practical viability as a detector of Violin-Mode resonances in the test

  14. Rheological properties of purified illite clays in glycerol/water suspensions

    Science.gov (United States)

    Dusenkova, I.; Malers, J.; Berzina-Cimdina, L.

    2015-04-01

    There are many studies about rheological properties of clay-water suspensions, but no published investigations about clay-glycerol suspensions. In this work apparent viscosity of previously purified illite containing clay fraction clay minerals were almost totally removed by centrifugation. All obtained suspensions behaved as shear-thinning fluids with multiple times higher viscosity than pure glycerol/water solutions. Reduction of clay fraction concentration by 5% decreased the apparent viscosity of 50% glycerol/water suspensions approximately 5 times. There was basically no difference in apparent viscosity between all four 50% glycerol/water suspensions, but in 90% glycerol/water suspensions samples from Iecava deposit showed slightly higher apparent viscosity, which could be affected by the particle size distribution.

  15. Modelling of Influence of Hypersonic Conditions on Gyroscopic Inertial Navigation Sensor Suspension

    Directory of Open Access Journals (Sweden)

    Korobiichuk Igor

    2017-06-01

    Full Text Available The upcoming hypersonic technologies pose a difficult task for air navigation systems. The article presents a designed model of elastic interaction of penetrating acoustic radiation with flat isotropic suspension elements of an inertial navigation sensor in the operational conditions of hypersonic flight. It has been shown that the acoustic transparency effect in the form of a spatial-frequency resonance becomes possible with simultaneous manifestation of the wave coincidence condition in the acoustic field and equality of the natural oscillation frequency of a finite-size plate and a forced oscillation frequency of an infinite plate. The effect can lead to additional measurement errors of the navigation system. Using the model, the worst and best case suspension oscillation frequencies can be determined, which will help during the design of a navigation system.

  16. Numerical study of suspensions of deformable particles.

    Science.gov (United States)

    Brandt, Luca; Rosti, Marco Edoardo

    2017-11-01

    We consider a model non-Newtonian fluid consisting of a suspension of deformable particles in a Newtonian solvent. Einstein showed in his pioneering work that the relative increase in effective viscosity is a linear function of the particle volume fraction for dilute suspensions of rigid particles. Inertia has been shown to introduce deviations from the behaviour predicted by the different empirical fits, an effect that can be related to an increase of the effective volume fraction. We here focus on the effect of elasticity, i.e. visco-elastic deformable particles. To tackle the problem at hand, we perform three-dimensional Direct Numerical Simulation of a plane Couette flow with a suspension of neutrally buoyant deformable viscous hyper-elastic particles. We show that elasticity produces a shear-thinning effect in elastic suspensions (in comparison to rigid ones) and that it can be understood in terms of a reduction of the effective volume fraction of the suspension. The deformation modifies the particle motion reducing the level of mutual interaction. Normal stress differences will also be considered. European Research Council, Grant No. ERC-2013-CoG- 616186, TRITOS; SNIC (the Swedish National Infrastructure for Computing).

  17. Connectivity percolation in suspensions of attractive square-well spherocylinders.

    Science.gov (United States)

    Dixit, Mohit; Meyer, Hugues; Schilling, Tanja

    2016-01-01

    We have studied the connectivity percolation transition in suspensions of attractive square-well spherocylinders by means of Monte Carlo simulation and connectedness percolation theory. In the 1980s the percolation threshold of slender fibers has been predicted to scale as the fibers' inverse aspect ratio [Phys. Rev. B 30, 3933 (1984)PRBMDO1098-012110.1103/PhysRevB.30.3933]. The main finding of our study is that the attractive spherocylinder system reaches this inverse scaling regime at much lower aspect ratios than found in suspensions of hard spherocylinders. We explain this difference by showing that third virial corrections of the pair connectedness functions, which are responsible for the deviation from the scaling regime, are less important for attractive potentials than for hard particles.

  18. Multiobjective optimisation of bogie suspension to boost speed on curves

    Science.gov (United States)

    Milad Mousavi-Bideleh, Seyed; Berbyuk, Viktor

    2016-01-01

    To improve safety and maximum admissible speed on different operational scenarios, multiobjective optimisation of bogie suspension components of a one-car railway vehicle model is considered. The vehicle model has 50 degrees of freedom and is developed in multibody dynamics software SIMPACK. Track shift force, running stability, and risk of derailment are selected as safety objective functions. The improved maximum admissible speeds of the vehicle on curves are determined based on the track plane accelerations up to 1.5 m/s2. To attenuate the number of design parameters for optimisation and improve the computational efficiency, a global sensitivity analysis is accomplished using the multiplicative dimensional reduction method (M-DRM). A multistep optimisation routine based on genetic algorithm (GA) and MATLAB/SIMPACK co-simulation is executed at three levels. The bogie conventional secondary and primary suspension components are chosen as the design parameters in the first two steps, respectively. In the last step semi-active suspension is in focus. The input electrical current to magnetorheological yaw dampers is optimised to guarantee an appropriate safety level. Semi-active controllers are also applied and the respective effects on bogie dynamics are explored. The safety Pareto optimised results are compared with those associated with in-service values. The global sensitivity analysis and multistep approach significantly reduced the number of design parameters and improved the computational efficiency of the optimisation. Furthermore, using the optimised values of design parameters give the possibility to run the vehicle up to 13% faster on curves while a satisfactory safety level is guaranteed. The results obtained can be used in Pareto optimisation and active bogie suspension design problems.

  19. Comparison of cortisol exposures and pharmacodynamic adrenal steroid responses to hydrocortisone suspension vs. commercial tablets.

    Science.gov (United States)

    Sarafoglou, Kyriakie; Gonzalez-Bolanos, Maria T; Zimmerman, Cheryl L; Boonstra, Timothy; Yaw Addo, O; Brundage, Richard

    2015-04-01

    The Endocrine Society Clinical Practice Guidelines on congenital adrenal hyperplasia (CAH) recommend against using hydrocortisone suspension based on a study that examined a commercial suspension. Our objective was to examine the absorption of an extemporaneously prepared hydrocortisone suspension and compare it to tablets. Secondary objectives were to evaluate the 17-hydroxyprogesterone and androstenedione adrenal steroid responses. Using a parallel design, 34 children diagnosed with CAH received either suspension (n = 9; median age 1.8 years) or tablets (n = 25; median age 7.5 years). Patients were given their usual morning hydrocortisone formulation and dose; 12 serial blood samples were obtained and the area under the curve (AUC) was calculated. The mg/m(2) dose-normalized cortisol AUCs were no different in the suspension and tablet groups (P = ·06), nor was there a significant difference in the C(max) or T(max) (P = .08 and P = .41, respectively). Although there were no differences in the 17-hydroxyprogesterone change-from-baseline AUCs, baseline concentrations, or the nadir concentrations when comparing suspension and tablet formulations, the androstenedione values were significantly lower as expected in the younger aged suspension group. Our results offer compelling evidence that an extemporaneously prepared hydrocortisone suspension provides comparable cortisol exposures to commercially available tablet formulations in children and can be used to safely and effectively treat CAH. © 2014, The American College of Clinical Pharmacology.

  20. Colloidal approach to dispersion and enhanced deaggregation of aqueous ferrite suspensions

    Science.gov (United States)

    Mandanas, Michael Patrick M.

    The role of solution and surface chemistry on deaggregation of calcined ferrites during attrition (stirred-media) milling of aqueous suspensions were investigated. Suspensions of commercially calcined Fe2O 3 powder (d50 ˜ 5.0 mum) were milled at different solid loadings and suspension pH. The drift of suspension pH, from pH 2.5 to pH 7.0, during solid loading experiments accounted for the observed reagglomeration with milling time. The observed deaggregation rates during pH stat milling, in the acidic region, can be related to (i) elevated solubility and (ii) enhanced dispersion via surface charge. Proton adsorption density during pH stat milling at different pH values is also comparable to existing potentiometric titration plots and can be related to deaggregation rates. A passivation-dispersion approach for dispersing manganese zinc ferrite (MnxZn(1 - x)Fe2O4) powder is presented. Addition of oxalic acid can help control dissolution reactions from particle surfaces and is subsequently dispersed with polyethyleneimine (PEI). Fully dissociated oxalic acid (pK1 = 1.2, pK2 = 4.3) solutions reacted with MnxZn(1 - x)Fe 2O4 leads to the formation of a uniform negative charge on the particle surface, resulting from the sparingly soluble salt formed on the surface. The resulting rheological data for passivation/dispersion of relatively high solid MnxZn(1 - x)Fe2O 4 suspensions (˜80 w/o, (˜40 v/o)) demonstrate improved colloid stability with improved rheological properties. Using the passivation dispersion scheme developed, deaggregation of commercially calcined MnxZn(1 - x)Fe2O4 powders during attrition milling was investigated. Reagglomeration is apparent when using a typical treatment, 2 w/w of a sulfonated based naphthalene condensate, during deaggregation of the calcined MnxZn(1 - x)Fe 2O4. However, is not observed for select oxalate/PEI treatments. The determined ideal treatment is 2 w/w oxalate and 3 w/w PEI based on the particle size and rheological

  1. Ride Quality Assessment of Bus Suspension System through Modal Frequency Response Approach

    Directory of Open Access Journals (Sweden)

    Y. S. Kong

    2014-09-01

    Full Text Available The ride dynamic characteristics of an urban bus were investigated through simulations with suspension component characteristics and were validated through field measurements. It was performed on highway road at a constant forward speed. A random vibration bus model with two parallel tracks of terrain profile was synthesized with superposition between the left and right sides as well as time delay between front and rear. The bus frequency response model was introduced with embedded modal extraction data to enhance computation efficiency. The simulation results of the bus model were derived in terms of acceleration PSD and frequency-weighted root mean square acceleration along the vertical axes at three locations, namely, driver side, middle, and rear passenger side, to obtain the overall bus ride performance. Another two sets of new leaf spring design were proposed as suspension parameter analysis. The simulation approach provides reasonably good results in evaluating passenger perception on ride and shows that the proposed new spring design can significantly improve the ride quality of the driver and passengers.

  2. Toward a general psychological model of tension and suspense.

    Science.gov (United States)

    Lehne, Moritz; Koelsch, Stefan

    2015-01-01

    Tension and suspense are powerful emotional experiences that occur in a wide variety of contexts (e.g., in music, film, literature, and everyday life). The omnipresence of tension and suspense suggests that they build on very basic cognitive and affective mechanisms. However, the psychological underpinnings of tension experiences remain largely unexplained, and tension and suspense are rarely discussed from a general, domain-independent perspective. In this paper, we argue that tension experiences in different contexts (e.g., musical tension or suspense in a movie) build on the same underlying psychological processes. We discuss key components of tension experiences and propose a domain-independent model of tension and suspense. According to this model, tension experiences originate from states of conflict, instability, dissonance, or uncertainty that trigger predictive processes directed at future events of emotional significance. We also discuss possible neural mechanisms underlying tension and suspense. The model provides a theoretical framework that can inform future empirical research on tension phenomena.

  3. Influence of vibration on structure rheological properties of a highly concentrated suspension

    Science.gov (United States)

    Ouriev Uriev, Boris N.; Uriev, Naum B.

    2005-08-01

    The influence of mechanical vibration on the flow properties of a highly concentrated multiphase food system is explored in this work. An experimental set-up was designed and adapted to a conventional rotational rheometer with precise rheological characterization capability. A number of calibration tests were performed prior to fundamental experiments with a highly concentrated chocolate suspension. Also, the prediction of wall slippage in shear flow under vibration was evaluated. Analysis of the boundary conditions shows that no side effects such as wall slippage or the Taylor effect were present during the shear experiment under vibration. It was found that superposition of mechanical vibration and shear flow radically decreases the shear viscosity. Comparison between reference shear viscosities at specified shear rates and those measured under vibration shows considerable differences in flow properties. Conversion of the behaviour of the concentrated suspension from strongly shear-thinning to Newtonian flow is reported. Also, the appearance of vibration-induced dilatancy as a new phenomenon is described. It is suggested to relate such phenomena to the non-equilibrium between structure formation and disintegration under vibration and hydrodynamic forces of shear flow. The influence of vibration on structure formation can be well observed during measurement of the yield value of the chocolate suspension under vibration. Comparison with reference data shows how sensitive the structure of the concentrated suspension is to vibration in general. The effects and observations revealed provide a solid basis for further fundamental investigations of structure formation regularities in the flow of any highly concentrated system. The results also show the technological potential for non-conventional treatment of concentrated, multiphase systems.

  4. Performance of a superconducting large-angle magnetic suspension

    International Nuclear Information System (INIS)

    Downer, J.R.; Bushko, D.A.; Gondhalekar, V.; Torti, R.P.

    1992-01-01

    SatCon Technology Corporation is working toward the development of an advanced-concept Control Moment Gyro (CMG). The advanced-concept CMG is sized for use as a slewing actuator for large space-based payloads. The design features a magnetically suspended composite rotor which contains a persistent-mode superconducting solenoid magnet. The rotor is suspended and gimballed by the interaction of the fields produced by the superconductor and an array of cryoresistive coils. The rotor spins in a liquid helium environment, while the control coils are liquid-hydrogen cooled. This design is capable of meeting the requirements of many high-performance slewing applications (27,000 Nm). The use of the magnetic suspension as rotor bearings, gimbal bearings, and gimbal torquers also substantially reduces the mass of the CMG system

  5. Shear-induced changes of electrical conductivity in suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Crawshaw, John; Meeten, Gerald [Schlumberger Cambridge Research, Cambridge (United Kingdom)

    2006-12-15

    The effect of shear on electrical conductivity (rheo-conduction) is studied to give information about particle behaviour in suspensions. Past work is reviewed, and expressions are derived for the rheo-conduction of a suspension of nonconducting spheroids in a conducting matrix for current flow, parallel and normal to the suspension flow direction. A simple apparatus to study rheo-conduction in pipe flow is described, and measurements of steady and time-dependent effects are reported for various suspensions of colloidal particles. Suspensions of anisometric rod- and platelike particles at low concentrations showed rheo-conductive changes of sign, magnitude and relaxation that were consistent with the particle shape, concentration and interactions. The rheo-conductive response decreased with increasing volume fraction for platelike kaolinite particles, attributed to orientational jamming. Spherical latex particles gave unexpected rheo-conductive changes consistent with shear disruption of a conductive network of particles. It is concluded that rheo-conduction measurements are a useful adjunct to conventional rheometry. (orig.)

  6. PERSPECTIVE TRANSPORT-POWER SYSTEM BASED ON THE INTEGRATION OF MAGLEV-TECHNOLOGY AND DISTRIBUTED PHOTO-ELECTRIC STATION

    Directory of Open Access Journals (Sweden)

    V. O. Dzenzerskiy

    2018-02-01

    Full Text Available Purpose. The research main purpose is the perfection of magnetolevitating technology on electrodynamic suspension and providing its functioning on the base of ecologically rational energy systems. It means creation of the MAGLEV transport-power system which uses renewable energy sources (in particular, photoelectric converters and is connected to national/local networks as an energy user and producer simultaneously. Methodology. Conducted research, analysis and summary conclusions are based both on the results of works on the given subject, and own works of authors. The methods of systems analysis and computer design of components of the large cyber-physical transport-power system were used during research conducting. Findings. The physical-technical foundations of conception of the perspective transport-power system, which includes high-speed ground vehicle on electrodynamic suspension and distributed photo-electric energy complex are developed. The adapt to the performance of the given transport type and guaranteeing its safe functioning in any weather terms. Originality. For the first time authors substantiated the possibility for creation of single transport complex uniting the speed magnetolevitating system and distributed power supply system on the base of sun energy. It is simultaneously the inalienable part of the precision fast-acting control system, working in the real-time mode. Practical value. The offered scientific-technical solution allows on the base of renewable energy source to solve the problems of power supply and a high-speed transport control. Due to the inclusion of the distributed power supply system into local intellectual networks on the SMART-grid technology it gives the possibility to optimize energy consumption of territories neighboring to high-speed way.

  7. Simple suspension culture system of human iPS cells maintaining their pluripotency for cardiac cell sheet engineering.

    Science.gov (United States)

    Haraguchi, Yuji; Matsuura, Katsuhisa; Shimizu, Tatsuya; Yamato, Masayuki; Okano, Teruo

    2015-12-01

    In this study, a simple three-dimensional (3D) suspension culture method for the expansion and cardiac differentiation of human induced pluripotent stem cells (hiPSCs) is reported. The culture methods were easily adapted from two-dimensional (2D) to 3D culture without any additional manipulations. When hiPSCs were directly applied to 3D culture from 2D in a single-cell suspension, only a few aggregated cells were observed. However, after 3 days, culture of the small hiPSC aggregates in a spinner flask at the optimal agitation rate created aggregates which were capable of cell passages from the single-cell suspension. Cell numbers increased to approximately 10-fold after 12 days of culture. The undifferentiated state of expanded hiPSCs was confirmed by flow cytometry, immunocytochemistry and quantitative RT-PCR, and the hiPSCs differentiated into three germ layers. When the hiPSCs were subsequently cultured in a flask using cardiac differentiation medium, expression of cardiac cell-specific genes and beating cardiomyocytes were observed. Furthermore, the culture of hiPSCs on Matrigel-coated dishes with serum-free medium containing activin A, BMP4 and FGF-2 enabled it to generate robust spontaneous beating cardiomyocytes and these cells expressed several cardiac cell-related genes, including HCN4, MLC-2a and MLC-2v. This suggests that the expanded hiPSCs might maintain the potential to differentiate into several types of cardiomyocytes, including pacemakers. Moreover, when cardiac cell sheets were fabricated using differentiated cardiomyocytes, they beat spontaneously and synchronously, indicating electrically communicative tissue. This simple culture system might enable the generation of sufficient amounts of beating cardiomyocytes for use in cardiac regenerative medicine and tissue engineering. Copyright © 2013 John Wiley & Sons, Ltd.

  8. Heat and mass transfer in particulate suspensions

    CERN Document Server

    Michaelides, Efstathios E (Stathis)

    2013-01-01

    Heat and Mass Transfer in Particulate Suspensions is a critical review of the subject of heat and mass transfer related to particulate Suspensions, which include both fluid-particles and fluid-droplet Suspensions. Fundamentals, recent advances and industrial applications are examined. The subject of particulate heat and mass transfer is currently driven by two significant applications: energy transformations –primarily combustion – and heat transfer equipment. The first includes particle and droplet combustion processes in engineering Suspensions as diverse as the Fluidized Bed Reactors (FBR’s) and Internal Combustion Engines (ICE’s). On the heat transfer side, cooling with nanofluids, which include nanoparticles, has attracted a great deal of attention in the last decade both from the fundamental and the applied side and has produced several scientific publications. A monograph that combines the fundamentals of heat transfer with particulates as well as the modern applications of the subject would be...

  9. Takagi-Sugeno Fuzzy Model of a One-Half Semiactive Vehicle Suspension: Lateral Approach

    Directory of Open Access Journals (Sweden)

    L. C. Félix-Herrán

    2015-01-01

    Full Text Available This work presents a novel semiactive model of a one-half lateral vehicle suspension. The contribution of this research is the inclusion of actuator dynamics (two magnetorheological nonlinear dampers in the modelling, which means that more realistic outcomes will be obtained, because, in real life, actuators have physical limitations. Takagi-Sugeno (T-S fuzzy approach is applied to a four-degree-of-freedom (4-DOF lateral one-half vehicle suspension. The system has two magnetorheological (MR dampers, whose numerical values come from a real characterization. T-S allows handling suspension’s components and actuator’s nonlinearities (hysteresis, saturation, and viscoplasticity by means of a set of linear subsystems interconnected via fuzzy membership functions. Due to their linearity, each subsystem can be handled with the very well-known control theory, for example, stability and performance indexes (this is an advantage of the T-S approach. To the best of authors’ knowledge, reported work does not include the aforementioned nonlinearities in the modelling. The generated model is validated via a case of study with simulation results. This research is paramount because it introduces a more accurate (the actuator dynamics, a complex nonlinear subsystem model that could be applied to one-half vehicle suspension control purposes. Suspension systems are extremely important for passenger comfort and stability in ground vehicles.

  10. Formulation design of oral pediatric Acetazolamide suspension: dose uniformity and physico-chemical stability study.

    Science.gov (United States)

    Santoveña, Ana; Suárez-González, Javier; Martín-Rodríguez, Cristina; Fariña, José B

    2017-03-01

    The formulation of an active pharmaceutical ingredient (API) as oral solution or suspension in pediatrics is a habitual practice, due to the non-existence of many commercialized medicines in pediatric doses. It is also the simplest way to prepare and administer them to this vulnerable population. The design of a formulation that assures the dose and the system stability depends on the physico-chemical properties of the API. In this study, we formulate a class IV API, Acetazolamide (AZM) as suspension for oral administration to pediatric population. The suspension must comply attributes of quality, safety and efficacy for this route of administration. We use simple compounding procedures, as well as fewer pure excipients, as recommended for children. Mass and uniformity content assays and physical and chemical stability studies were performed. To quantify the API an UPLC method was used. We verified the physico-chemical stability of the suspensions and that they passed the mass test of the European Pharmacopeia (EP), but not the dose uniformity test. This reveals that AZM must be formulated as liquid forms with a more complex system of excipients (not usually indicated in pediatrics), or otherwise solid forms capable of assuring uniformity of mass and dose for every dosage unit.

  11. Association between the physical stability of flurbiprofen suspension and the interaction of HPMC/SDS

    Directory of Open Access Journals (Sweden)

    Hongyu Wang

    2018-01-01

    Full Text Available The anionic surfactant sodium dodecylsulfate (SDS has improved the physical stability of flurbiprofen (FBP suspension, which was suspended by 0.2% (w/v hydroxypropylmethyl cellulose (HPMC, K4M. Therefore, the physical stability of FBP suspensions and the interaction of HPMC/SDS were studied, and a certain association between them was revealed. The anti-solvent precipitation method was used to prepare suspensions. The apparent drug concentration from different sites was evaluated to get the dispersion of drug actually. The process of flocculation and deflocculation with the addition of SDS was caught by analyzing the morphology of the suspended particles. The physical stability of the FBP suspensions was characterized mainly by measuring the re-dispersion time, the zeta potential and particle size. Meanwhile, conductivity measurements were carried out to obtain the characteristic concentrations of SDS in HPMC/SDS system. The viscosities, the abilities for improving the solubility and wettability of FBP in the separate and mixed HPMC/SDS solutions were also contrasted respectively. The suspensions prepared with HPMC/SDS possessed better physical stability. The suspensions were uniform when the concentration of SDS was between the critical adsorption concentration (CAC and the polymer saturation point (PSP. After PSP, the uniformity became worse and worse until the SDS was enough to form a deflocculation state. Besides, the re-dispersion time of FBP suspensions was longest when the concentration of SDS around CAC and shorter by shorter after the critical micelle concentration (CMC. The article provided a new sight on the relation between the interaction of excipient matrix and pharmaceutical preparations.

  12. Suspension of oysters reduces the populations of Vibrio parahaemolyticus and Vibrio vulnificus.

    Science.gov (United States)

    Cole, K M; Supan, J; Ramirez, A; Johnson, C N

    2015-09-01

    Vibrio parahaemolyticus (Vp) and Vibrio vulnificus (Vv) are associated with the consumption of raw oysters and cause illnesses ranging from simple gastroenteritis to life-threatening septicaemia. These halophilic bacteria are frequently found in marine and estuarine systems, accumulating within the tissues of a number of aquatic organisms and passing on to humans after consumption, through contaminated water, or via open wounds. As benthic organisms capable of filtering 40 gallons of water per hour, sediment is an important source of potentially pathogenic vibrios in oysters destined for raw consumption. This research used off-bottom oyster culture to reduce vibrio concentrations in oysters. Colony hybridization was used to enumerate Vp and Vv in bottom and suspended oysters. Vv and Vp concentrations were generally lower in oysters suspended off-bottom, and suspension decreased vibrio loads in oysters by an average of 13%. Suspension of oysters reduced vibrio concentrations. This study found that oyster suspension significantly reduced some populations of potentially pathogenic vibrios. These results indicate that oyster suspension could be a viable approach for preharvest treatment to reduce illness in consumers of raw oysters. © 2015 The Society for Applied Microbiology.

  13. Three-particle correlation functions of quasi-two-dimensional one-component and binary colloid suspensions.

    Science.gov (United States)

    Ho, Hau My; Lin, Binhua; Rice, Stuart A

    2006-11-14

    We report the results of experimental determinations of the triplet correlation functions of quasi-two-dimensional one-component and binary colloid suspensions in which the colloid-colloid interaction is short ranged. The suspensions studied range in density from modestly dilute to solid. The triplet correlation function of the one-component colloid system reveals extensive ordering deep in the liquid phase. At the same density the ordering of the larger diameter component in a binary colloid system is greatly diminished by a very small amount of the smaller diameter component. The possible utilization of information contained in the triplet correlation function in the theory of melting of a quasi-two-dimensional system is briefly discussed.

  14. Identification of Brucella genus and eight Brucella species by Luminex bead-based suspension array.

    Science.gov (United States)

    Lusk Pfefer, Tina S; Timme, Ruth; Kase, Julie A

    2018-04-01

    Globally, unpasteurized milk products are vehicles for the transmission of brucellosis, a zoonosis responsible for cases of foodborne illness in the United States and elsewhere. Existing PCR assays to detect Brucella species are restricted by the resolution of band sizes on a gel or the number of fluorescent channels in a single real-time system. The Luminex bead-based suspension array is performed in a 96-well plate allowing for high throughput screening of up to 100 targets in one sample with easily discernible results. We have developed an array using the Bio-Plex 200 to differentiate the most common Brucella species: B. abortus, B. melitensis, B. suis, B. suis bv5, B. canis, B. ovis, B. pinnipedia, and B. neotomae, as well as Brucella genus. All probes showed high specificity, with no cross-reaction with non-Brucella strains. We could detect pure DNA from B. abortus, B. melitensis, and genus-level Brucella at concentrations of ≤5 fg/μL. Pure DNA from all other species tested positive at concentrations well below 500 fg/μL and we positively identified B. neotomae in six artificially contaminated cheese and milk products. An intra-laboratory verification further demonstrated the assay's accuracy and robustness in the rapid screening (3-4 h including PCR) of DNA. Published by Elsevier Ltd.

  15. Bidisperse and polydisperse suspension rheology at large solid fraction

    Energy Technology Data Exchange (ETDEWEB)

    Pednekar, Sidhant [Benjamin Levich Institute and Department of Chemical Engineering, The City College of New York, New York, New York 10031; Chun, Jaehun [Pacific Northwest National Laboratory, Richland, Washington 99352; Morris, Jeffrey F. [Benjamin Levich Institute and Department of Chemical Engineering, The City College of New York, New York, New York 10031

    2018-03-01

    At the same solid volume fraction, bidisperse and polydisperse suspensions display lower viscosities, and weaker normal stress response, compared to monodisperse suspensions. The reduction of viscosity associated with size distribution can be explained by an increase of the maximum flowable, or jamming, solid fraction. In this work, concentrated or "dense" suspensions are simulated under strong shearing, where thermal motion and repulsive forces are negligible, but we allow for particle contact with a mild frictional interaction with interparticle friction coefficient of 0.2. Aspects of bidisperse suspension rheology are first revisited to establish that the approach reproduces established trends; the study of bidisperse suspensions at size ratios of large to small particle radii (2 to 4) shows that a minimum in the viscosity occurs for zeta slightly above 0.5, where zeta=phi_{large}/phi is the fraction of the total solid volume occupied by the large particles. The simple shear flows of polydisperse suspensions with truncated normal and log normal size distributions, and bidisperse suspensions which are statistically equivalent with these polydisperse cases up to third moment of the size distribution, are simulated and the rheologies are extracted. Prior work shows that such distributions with equivalent low-order moments have similar phi_{m}, and the rheological behaviors of normal, log normal and bidisperse cases are shown to be in close agreement for a wide range of standard deviation in particle size, with standard correlations which are functionally dependent on phi/phi_{m} providing excellent agreement with the rheology found in simulation. The close agreement of both viscosity and normal stress response between bi- and polydisperse suspensions demonstrates the controlling in influence of the maximum packing fraction in noncolloidal suspensions. Microstructural investigations and the stress distribution according to particle size are also presented.

  16. A New, General Strategy for Fabricating Highly Concentrated and Viscoplastic Suspensions Based on a Structural Approach To Modulate Interparticle Interaction.

    Science.gov (United States)

    Sakurai, Shunsuke; Kamada, Fuminori; Kobashi, Kazufumi; Futaba, Don N; Hata, Kenji

    2018-01-24

    We report a general strategy to fabricate highly concentrated, viscoplastic and stable suspensions by designing the particle surface structure to control the interparticle attractive forces. Unlike conventional methods, where the choice of solvent is critical in balancing interparticle interactions, suspensions showing excellent stability and viscoplastic properties were made using various solvents. We demonstrated this approach using highly sparse agglomerates of carbon nanotubes (CNTs) as the particles. Our results revealed that the essential feature of the CNT agglomerate to fabricate these suspensions was high porosity with a spacing size much smaller than the overall size, which was only possible using long single-walled carbon nanotubes (SWNTs). In this way, the agglomerate surface was characterized by fine network of CNT bundles. These suspensions exhibited solid-like behavior at rest (characterized by a high yield stress of c.a. 100 Pa) and a liquid-like behavior when subjected to a stress (characterized by a significant drop of an apparent viscosity to 1 Pa·s at a shear rate of 1000 s -1 ). Furthermore, in contrast to conventionally fabricated suspensions, these "CNT pastes" exhibited exceptional stability at rest, under flow, and at extremely high concentrations during the drying process, with only a weakly observable dependence on solvent type. As a result, highly uniform micrometer-thick SWNT films were successfully fabricated by dried blade-coated films of these pastes. Finally, we developed a simple, semiempirical model and clarified the importance of the CNT agglomerate microstructure (the ratio of spacing size/particle size and porosity) on tailoring the cohesive forces between particles to fabricate stable viscoplastic suspensions.

  17. Rear suspension design for an in-wheel-drive electric car

    NARCIS (Netherlands)

    George, Ashwin Dayal; Besselink, Igo

    2016-01-01

    The in-wheel motor configuration can provide more flexibility to electric car design, making the car more compact and lightweight. However, current suspension systems are not designed to incorporate an in-wheel powertrain, and studies have shown deterioration in ride comfort and handling when more

  18. Interactions in YBa2Cu3O7-x aqueous suspensions

    International Nuclear Information System (INIS)

    Dusoulier, Laurent; Cloots, Rudi; Vertruyen, Benedicte; Garcia-Fierro, Jose L.; Moreno, Rodrigo; Ferrari, Begona

    2009-01-01

    Surface charging mechanism of YBa 2 Cu 3 O 7-x (YBCO) particles in water has been investigated in order to understand their colloidal behaviour and stabilise concentrated suspensions. A broad study relating the suspension parameters (pH and zeta potential) vs. the conditions of the suspension performance (atmosphere and time) has been shown and discussed. The zeta potential values remain positive in all the pH range for the highest powder concentration studied (10 g l -1 ), evidencing a large influence of the solid content in the particle charge. The chemistry of YBa 2 Cu 3 O 7-x in water has been studied through the chemical analysis of the supernatant by inductively coupled plasma (ICP), and the surface analysis of the particles by X-ray diffraction analysis (XRD) and X-ray photoelectron spectroscopy (XPS). The presence of BaCO 3 , CuO, and the hydrolysed Ba species, such as Ba(OH) 2 and Ba(OH) + , at the particles surface has been evaluated as a function of the powder concentration. Based on these analyses, the dependence of the colloidal behaviour of YBCO on the presence of Ba soluble species has been determined. A stabilisation mechanism for YBCO particles in aqueous suspension focus on the powders deleterious minimization was proposed.

  19. Stability of allopurinol and of five antineoplastics in suspension.

    Science.gov (United States)

    Dressman, J B; Poust, R I

    1983-04-01

    The stability of allopurinol, azathioprine, chlorambucil, melphalan, mercaptopurine, and thioguanine each in an extemporaneously prepared suspension was studied. Tablets of each drug were crushed, mixed with a suspending agent, and brought to a final volume of 10, 15, or 20 ml with a 2:1 mixture of simple syrup and wild cherry syrup. Suspensions were prepared in the following concentrations: allopurinol (20 mg/ml), azathioprine (50 mg/ml), chlorambucil (2 mg/ml), melphalan (2 mg/ml), mercaptopurine (50 mg/ml), and thioguanine (40 mg/ml). Using high-performance liquid chromatography or ultraviolet scans, duplicate assays were performed on each suspension periodically during storage for up to 84 days at ambient room temperature or 5 degrees C. The time required for the suspensions to drop below 90% of labeled strength was used as an indicator of drug stability. Allopurinol and azathioprine were stable for at least 56 days at room temperature and at 5 degrees C. Chlorambucil decomposed rapidly at room temperature but was stable for seven days when stored at 5 degrees C. Melphalan suspensions did not meet the stated criteria for stability even at the time of initial assay. Mercaptopurine and thioguanine were stable for 14 and 84 days, respectively, at room temperature; at 5 degrees C, assay values dropped below those obtained at room temperature. In the suspension formulation tested, allopurinol, azathioprine, mercaptopurine, and thioguanine are stable for at least 14 days at room temperature; chlorambucil suspensions should be refrigerated and discarded after seven days. Melphalan decomposes too rapidly to make this suspension formulation feasible for extemporaneous compounding.

  20. Correlation between structure and rheological properties of suspension of nanosized powders

    Energy Technology Data Exchange (ETDEWEB)

    Tabellion, J.; Clasen, R. [Saarland Univ., Saarbruecken (Germany). Dept. of Powder Technology; Reinshagen, J.; Oberacker, R.; Hoffmann, M.J. [Karlsruhe Univ. (Germany). Inst. for Ceramics in Mechanical Engineering

    2002-07-01

    Since the properties of a ceramic green body and compact produced thereof are strongly influenced by the properties of the suspension used, controlling structure and properties of a suspension is a very important issue in ceramic manufacturing. Macroscopically, the rheological properties of a suspension are the key parameters that influence the behaviour during the shaping process. The rheological behaviour of aqueous suspensions of nanosized fumed silica (DEGUSSA, Aerosil OX50) with different amounts of OX50 (10 to 50 wt.%) was measured over a pH-range from 1 to 13 by means of rotational viscosimetry. A distinct maximum of the viscosity was observed for a pH of about 7 to 8, independent of the solid content of the suspensions. Since the rheological behaviour of the suspensions could not be explained by the {zeta}-Potential measured for OX50, the suspensions were investigated by means of so-called cryo-SEM characterization. A droplet of the suspension is quench-frozen in subcooled nitrogen (-210 C), prepared and the water is sublimed at -90 C. Thus it was possible to visualize the agglomerate structure of the primary OX50-particles within the suspensions. (orig.)

  1. EOS suspension test for the assessment of spinal flexibility in adolescent idiopathic scoliosis.

    Science.gov (United States)

    Hirsch, Caroline; Ilharreborde, Brice; Mazda, Keyvan

    2015-07-01

    The assessment of spinal flexibility is essential for the planning of adolescent idiopathic scoliosis (AIS) surgery. Various radiographic methods have been used but none of them has shown any superiority. The new low-dose stereography system EOS (EOS imaging, Paris, France) captures whole body images in a single scan without vertical distortion. EOS is now used in routine clinical use for AIS follow-up. The aim of this study was to prospectively evaluate the feasibility and the reproducibility of a new suspension test during the EOS imaging for the assessment of spinal flexibility in AIS. Fifty AIS patients scheduled for surgery were prospectively included. For each patient, a standard EOS radiograph was obtained, then a suspension test in the EOS and a classic traction test on the cotrel frame were performed. The examinations were compared in terms of radiation exposure, tolerance, mean traction force, and Cobb angle reduction for each curve. Axial and sagittal reductions during suspension were analyzed on three-dimensional EOS reconstructions. The tolerance of the suspension test was lower than the traction test but it was less operator dependent. Radiation exposure was 7 times lower during the suspension test. Cobb angle reductions achieved in the proximal and main curves by the two tests were similar. The traction test achieved greater reduction of the distal curve. Flexibility in the axial plane and in the sagittal plane was analyzed with the suspension test. The reduction in apical rotation was not correlated with the reduction in Cobb angle. The EOS suspension test can be used for the assessment of spinal flexibility in AIS. It gives a global vision of the deformity with new flexibility indices in the axial and sagittal planes.

  2. First results from the ‘Violin-Mode’ tests on an advanced LIGO suspension at MIT

    Science.gov (United States)

    Lockerbie, N. A.; Carbone, L.; Shapiro, B.; Tokmakov, K. V.; Bell, A.; Strain, K. A.

    2011-12-01

    This paper describes the first results from ‘Violin-Mode’ measurements made on the four suspension fibres of a fully suspended 40 kg test mass. These measurements were made at the LIGO lab, Gravitational Wave Observatory test facility, at MIT. Here, an aluminium-alloy (dummy) test mass, simulating an advanced LIGO (Laser Interferometer Gravitational Wave Observatory) test mass/mirror, had been suspended in air from a test suspension by four fused-silica suspension fibres, each measuring 400 µm in diameter × 600 mm long. Violin-Mode measurements were made on these highly tensioned fibres by retrofitting a prototype system of four novel shadow sensors to the test suspension, one per fibre, these sensors having, collectively, a displacement sensitivity of (6.9 ± 1.3) × 10-11 m (rms) Hz-1/2, at 500 Hz, over a measuring span of ±0.1 mm. Violin-Mode fundamental resonances were detected in all four fibres: with frequencies ˜ 485 Hz when the test mass was supported lightly from below, and at ˜500 Hz when it was fully suspended. In the latter case the Violin-Mode detection took place whilst the test mass, together with its suspension fibres, was undergoing relatively large-amplitude ‘pendulum-mode’ motion, at ˜0.6 Hz. This motion was measured to have a peak-peak amplitude at one of the suspension fibres of up to ˜140 µm (35 µm, rms)—the shadow sensors each having subsidiary outputs for monitoring such low-frequency, large amplitude, motion. Under fully suspended conditions, a calibrated Violin-Mode ‘free-oscillation’ amplitude of 430 ± 20 picometres, rms, was measured at 500.875 Hz, in the same suspension fibre which was found to be undergoing, simultaneously, the ˜140 µm peak-peak motion. Over the bandwidth monitored (dc to 3.2 kHz), Violin-Mode harmonics up to the sixth were recorded in an evoked response. It was concluded that the prototype system had demonstrated amply its practical viability as a detector of Violin-Mode resonances in the

  3. Phagocytosis in phosphate chromium (III) suspensions

    International Nuclear Information System (INIS)

    Cruz-Arencibia, Jorge; Fano Machín, Yoiz; Cruz-Morales, Ahmed; Tamayo Fuente, Radamés; Morín-Zorrilla, José

    2015-01-01

    Phagocytosis in vivo and in vitro of a suspension of chromic phosphate (III) labeled with 51 Cr and 32 P is studied. The radioactive particles dispersed in a media of 2 % gelatin in acetate buffer pH 4-4.5 have a predominant size of 0.8 μm and 5 μm. According with biodistribution experiments in rats after 30 minutes near the 80 % of radioactivity is registered in the liver, probably associated with phagocytosis of the particles by liver Kupffer cells. Is also showed that the suspension particles are phagocytized in vitro by mouse peritoneal macrophages. This facts indicate that the studied suspension have appropriate characteristics to be used in radiosynoviorthesis according to the principal action mechanism described for this procedure, particles phagocytosis by cells present in the inflamed synovium. (author)

  4. Statistical analysis of modal parameters of a suspension bridge based on Bayesian spectral density approach and SHM data

    Science.gov (United States)

    Li, Zhijun; Feng, Maria Q.; Luo, Longxi; Feng, Dongming; Xu, Xiuli

    2018-01-01

    Uncertainty of modal parameters estimation appear in structural health monitoring (SHM) practice of civil engineering to quite some significant extent due to environmental influences and modeling errors. Reasonable methodologies are needed for processing the uncertainty. Bayesian inference can provide a promising and feasible identification solution for the purpose of SHM. However, there are relatively few researches on the application of Bayesian spectral method in the modal identification using SHM data sets. To extract modal parameters from large data sets collected by SHM system, the Bayesian spectral density algorithm was applied to address the uncertainty of mode extraction from output-only response of a long-span suspension bridge. The posterior most possible values of modal parameters and their uncertainties were estimated through Bayesian inference. A long-term variation and statistical analysis was performed using the sensor data sets collected from the SHM system of the suspension bridge over a one-year period. The t location-scale distribution was shown to be a better candidate function for frequencies of lower modes. On the other hand, the burr distribution provided the best fitting to the higher modes which are sensitive to the temperature. In addition, wind-induced variation of modal parameters was also investigated. It was observed that both the damping ratios and modal forces increased during the period of typhoon excitations. Meanwhile, the modal damping ratios exhibit significant correlation with the spectral intensities of the corresponding modal forces.

  5. 15 CFR 14.13 - Debarment and suspension.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Debarment and suspension. 14.13 Section 14.13 Commerce and Foreign Trade Office of the Secretary of Commerce UNIFORM ADMINISTRATIVE... shall comply with the nonprocurement debarment and suspension common rule implementing E.O.s 12549 and...

  6. 19 CFR 210.23 - Suspension of investigation.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 3 2010-04-01 2010-04-01 false Suspension of investigation. 210.23 Section 210.23 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION INVESTIGATIONS OF UNFAIR PRACTICES IN IMPORT TRADE ADJUDICATION AND ENFORCEMENT Motions § 210.23 Suspension of investigation. Any party may move to...

  7. Long time diffusion in suspensions of interacting charged colloids

    NARCIS (Netherlands)

    Schepper, I.M. de; Cohen, E.G.D.; Pusey, P.N.; Lekkerkerker, H.N.W.

    1989-01-01

    A new expression is given for the long time diffusion coefficient DL(k) of charged interacting colloidal spheres in suspension, as a function of the wavenumber k, near k = km, where the static structure factor has a maximum. The expression is based on a physical analogy between a mode description

  8. EDITORIAL: Colloidal suspensions Colloidal suspensions

    Science.gov (United States)

    Petukhov, Andrei; Kegel, Willem; van Duijneveldt, Jeroen

    2011-05-01

    fluid-fluid interface [2]. Together with Remco Tuinier, Henk has recently completed a book in this area which is to appear later this year. A major theme in Henk's research is that of phase transitions in lyotropic liquid crystals. Henk, together with Daan Frenkel and Alain Stroobants, realized in the 1980s that a smectic phase in dispersions of rod-like particles can be stable without the presence of attractive interactions, similar to nematic ordering as predicted earlier by Onsager [3]. Together with Gert-Jan Vroege he wrote a seminal review in this area [4]. Henk once said that 'one can only truly develop one colloidal model system in one's career' and in his case this must be that of gibbsite platelets. Initially Henk's group pursued another polymorph of aluminium hydroxide, boehmite, which forms rod-like particles [5], which already displayed nematic liquid crystal phases. The real breakthrough came when the same precursors treated the produced gibbsite platelets slightly differently. These reliably form a discotic nematic phase [6] and, despite the polydispersity in their diameter, a columnar phase [7]. A theme encompassing a wide range of soft matter systems is that of colloidal dynamics and phase transition kinetics. Many colloidal systems have a tendency to get stuck in metastable states, such as gels or glasses. This is a nuisance if one wishes to study phase transitions, but it is of great practical significance. Such issues feature in many of Henk's publications, and with Valerie Anderson he wrote a highly cited review in this area [8]. Henk Lekkerkerker has also invested significant effort into the promotion of synchrotron radiation studies of colloidal suspensions. He was one of the great supporters of the Dutch-Belgian beamline 'DUBBLE' project at the ESRF [9]. He attended one of the very first experiments in Grenoble in 1999, which led to a Nature publication [7]. He was strongly involved in many other experiments which followed and also has been a

  9. On reactive suspension plasma spraying of calcium titanate

    OpenAIRE

    Kotlan, J. (Jiří); Pala, Z. (Zdeněk); Mušálek, R. (Radek); Ctibor, P. (Pavel)

    2016-01-01

    This study shows possibility of preparation of calcium titanate powder and coatings by reactive suspension plasma spraying. Suspension of mixture of calcium carbonate (CaCO3) and titanium dioxide (TiO2) powders in ethanol was fed into hybrid plasma torch with a DC-arc stabilized by a water–argon mixture (WSP-H 500). Various feeding distances and angles were used in order to optimize suspension feeding conditions. In the next step, the coatings were deposited on stainless steel substrates and ...

  10. A contribution to the investigation of the heat load of shock absorbers of semi-active suspensions in motor vehicles

    Directory of Open Access Journals (Sweden)

    Miroslav D. Demić

    2013-10-01

    Full Text Available Dynamic simulation, based on modeling, has a significant role during the process of vehicle development. It is especially important in the first stages of vehicle design, when relevant vehicle parameters are to be defined. Shock absorbers as executive parts of vehicle semi-active suspension systems suffer thermal loads, which may result in damage and degradation of ther characteristics. Therefore,this paper shows an attempt to analyze converting of mechanical work into heat by using the dynamic simulation method. Introduction Shock absorbers are integral elements of semi-active suspension systems for vehicles (hereinafter SASS. They directly affect the active vehicle safety. The role of shock absorbers is to absorb mechanical vibrations transferred from the road and to ensure the safety of passengers in a vehicle. The kinetic energy of vehicle vibrations transforms into mechanical work or heat in shock absorbers. In practice, in the first stage of vehicle development, the shock absorber parameters are chosen from the condition of damping vibrations of vehicles, but their thermal shock loads should be also taken into account. Motor vehicles have complex dynamic characteristics manifested by spatial movement, parameters change during operation, a number of disturbing influences, backlash, friction, hysteresis, etc. The above-mentioned dynamic phenomena, especially vibration, lead to fatigue of driver and users, reduce the life of the vehicle and its systems, etc. The main objective of the system is to reduce the reliance of the above-mentioned negative effects, improving the vehicle behavior on the road and allow the exploitation of vehicles in a wide range of service conditions. Classical systems cannot satisfiy these conditions, so there was a need to introduce new suspension systems with controlled characteristics (briefly called "semi-active", or "active" systems. Oscillatory model of vehicle The differential equations of vibratory motion of

  11. Determining Quiescent Colloidal Suspension Viscosities Using the Green-Kubo Relation and Image-Based Stress Measurements

    Science.gov (United States)

    Lin, Neil Y. C.; Bierbaum, Matthew; Cohen, Itai

    2017-09-01

    By combining confocal microscopy and stress assessment from local structural anisotropy, we directly measure stresses in 3D quiescent colloidal liquids. Our noninvasive and nonperturbative method allows us to measure forces ≲50 fN with a small and tunable probing volume, enabling us to resolve the stress fluctuations arising from particle thermal motions. We use the Green-Kubo relation to relate these measured stress fluctuations to the bulk Brownian viscosity at different volume fractions, comparing against simulations and conventional rheometry measurements. We find that the Green-Kubo analysis gives excellent agreement with these prior results, suggesting that similar methods could be applied to investigations of local flow properties in many poorly understood far-from-equilibrium systems, including suspensions that are glassy, strongly sheared, or highly confined.

  12. Gastrointestinal tract wall visualization and distention during abdominal and pelvic multidetector CT with a neutral barium sulphate suspension: comparison with positive barium sulphate suspension and with water.

    Science.gov (United States)

    Oliva, M R; Erturk, S M; Ichikawa, T; Rocha, T; Ros, P R; Silverman, S G; Mortele, K J

    2012-01-01

    When examining patients with contrast-enhanced multidetector-row CT, we determined if the stomach and small bowel were visualized and distended better with a neutral barium sulphate suspension than with positive barium sulphate suspension or water. After obtaining approval from our institutional review board, 156 patients (women: 84; mean age: 54 yrs) with no history of gastrointestinal tract disease were randomized prospectively to receive orally either 900 ml of neutral (0.1% w/v) barium sulphate suspension (n = 53), 900 ml of positive (2.1% w/v) barium sulphate suspension (n = 53), or 900 ml of water (n = 50), prior to undergoing contrast-enhanced abdominal and pelvic multidetector-row CT. Two independent radiologists evaluated the stomach, and small bowel, for luminal distension and wall visualization, using a five point scale. Results were compared using Kruskal-Wallis and Mann-Whitney U tests. The walls of the stomach, and small bowel were visualized better in patients who were administered neutral barium sulphate suspension than those who were administered either positive barium sulphate suspension (p barium sulphate suspension, the stomach and small bowel were distended better compared to patients administered water (p barium sulphate suspension (p contrast-enhanced abdominal and pelvic multidetector-row CT, orally administered neutral barium sulphate suspension allows the gastrointestinal tract to be visualized and distended better than either positive barium sulphate suspension, or water.

  13. A comparison between the use of intravenous bags and the Heelift suspension boot to prevent pressure ulcers in orthopedic patients.

    Science.gov (United States)

    Bales, Isabel

    2012-03-01

    The heel is the second most common area where patients develop pressure ulcers (PrUs). Some of the interventions commonly used today to prevent PrUs have not been empirically tested, whereas other interventions have been studied and shown to prevent heel PrUs. Currently, there are no specific studies comparing a pressure-relieving suspension boot with the use of intravenous bags. This quasi-experimental study compared the use of these interventions to determine which intervention was more effective for heel-pressure relief. The target population consisted of a convenience sample of 30 patients admitted to the hospital for hip or knee surgery. Subjects were randomized to intravenous bags or pressure-relieving suspension boots. Daily pressure assessment of heels and the Achilles area was completed using validated pressure scales. Data were analyzed using the SPSS statistical program and were then used to determine the extent to which signs and symptoms of pressure were associated with each intervention. The results demonstrated a significant difference between the pressure-relieving suspension boot and the intravenous bag as heel-pressure-relief methods. Based on the statistical results of this study, the pressure-relieving suspension boot (Heelift; DM Systems Inc, Evanston, Illinois) was the better clinical intervention for patients with decreased mobility.

  14. Simulation Research on an Electric Vehicle Chassis System Based on a Collaborative Control System

    Directory of Open Access Journals (Sweden)

    Nenglian Feng

    2013-01-01

    Full Text Available This paper presents a collaborative control system for an electric vehicle chassis based on a centralized and hierarchical control architecture. The centralized controller was designed for the suspension and steering system, which is used for improving ride comfort and handling stability; the hierarchical controller was designed for the braking system, which is used for distributing the proportion of hydraulic braking and regenerative braking to improve braking performance. These two sub-controllers function at the same level of the vehicle chassis control system. In order to reduce the potential conflict between the two sub-controllers and realize a coordination optimization of electric vehicle performance, a collaborative controller was built, which serves as the upper controller to carry out an overall coordination analysis according to vehicle signals and revises the decisions of sub-controllers. A simulation experiment was carried out with the MATLAB/Simulink software. The simulation results show that the proposed collaborative control system can achieve an optimized vehicle handling stability and braking safety.

  15. Standardisation of magnetic nanoparticles in liquid suspension

    International Nuclear Information System (INIS)

    Wells, James; Kazakova, Olga; Posth, Oliver; Steinhoff, Uwe; Petronis, Sarunas; Bogart, Lara K; Southern, Paul; Pankhurst, Quentin; Johansson, Christer

    2017-01-01

    Suspensions of magnetic nanoparticles offer diverse opportunities for technology innovation, spanning a large number of industry sectors from imaging and actuation based applications in biomedicine and biotechnology, through large-scale environmental remediation uses such as water purification, to engineering-based applications such as position-controlled lubricants and soaps. Continuous advances in their manufacture have produced an ever-growing range of products, each with their own unique properties. At the same time, the characterisation of magnetic nanoparticles is often complex, and expert knowledge is needed to correctly interpret the measurement data. In many cases, the stringent requirements of the end-user technologies dictate that magnetic nanoparticle products should be clearly defined, well characterised, consistent and safe; or to put it another way—standardised. The aims of this document are to outline the concepts and terminology necessary for discussion of magnetic nanoparticles, to examine the current state-of-the-art in characterisation methods necessary for the most prominent applications of magnetic nanoparticle suspensions, to suggest a possible structure for the future development of standardisation within the field, and to identify areas and topics which deserve to be the focus of future work items. We discuss potential roadmaps for the future standardisation of this developing industry, and the likely challenges to be encountered along the way. (topical review)

  16. Standardisation of magnetic nanoparticles in liquid suspension

    Science.gov (United States)

    Wells, James; Kazakova, Olga; Posth, Oliver; Steinhoff, Uwe; Petronis, Sarunas; Bogart, Lara K.; Southern, Paul; Pankhurst, Quentin; Johansson, Christer

    2017-09-01

    Suspensions of magnetic nanoparticles offer diverse opportunities for technology innovation, spanning a large number of industry sectors from imaging and actuation based applications in biomedicine and biotechnology, through large-scale environmental remediation uses such as water purification, to engineering-based applications such as position-controlled lubricants and soaps. Continuous advances in their manufacture have produced an ever-growing range of products, each with their own unique properties. At the same time, the characterisation of magnetic nanoparticles is often complex, and expert knowledge is needed to correctly interpret the measurement data. In many cases, the stringent requirements of the end-user technologies dictate that magnetic nanoparticle products should be clearly defined, well characterised, consistent and safe; or to put it another way—standardised. The aims of this document are to outline the concepts and terminology necessary for discussion of magnetic nanoparticles, to examine the current state-of-the-art in characterisation methods necessary for the most prominent applications of magnetic nanoparticle suspensions, to suggest a possible structure for the future development of standardisation within the field, and to identify areas and topics which deserve to be the focus of future work items. We discuss potential roadmaps for the future standardisation of this developing industry, and the likely challenges to be encountered along the way.

  17. Universal behaviour of silica suspensions gelled under shear

    International Nuclear Information System (INIS)

    Hanley, H J M; Muzny, C D; Bartlett, J; Drabarek, E

    2007-01-01

    The shear-influenced gelation of three aqueous suspensions consisting of silica particles of nominal diameter 7, 12 and 24 nm, respectively, is reported. It is shown that the viscosity/stress of a gelling system increases with time after gel initiation, reaches a maximum, then falls to a plateau value. A very simple relation between this maximum stress and the precursor volume fraction is verified experimentally

  18. Optimization Analysis Model of Self-Anchored Suspension Bridge

    Directory of Open Access Journals (Sweden)

    Pengzhen Lu

    2014-01-01

    Full Text Available The hangers of self-anchored suspension bridge need to be tensioned suitably during construction. In view of this point, a simplified optimization calculation method of cable force for self-anchored suspension bridge has been developed based on optimization theories, such as minimum bending energy method, and internal force balanced method, influence matrix method. Meanwhile, combined with the weak coherence of main cable and the adjacently interaction of hanger forces, a simplified analysis method is developed using MATLAB, which is then compared with the optimization method that consider the main cable's geometric nonlinearity with software ANSYS in an actual example bridge calculation. This contrast proves the weak coherence of main cable displacement and the limitation of the adjacent cable force influence. Furthermore, a tension program that is of great reference value has been developed; some important conclusions, advices, and attention points have been summarized.

  19. Preparation of conjugated polymer suspensions by using ultrasonic atomizer

    Energy Technology Data Exchange (ETDEWEB)

    Tada, Kazuya, E-mail: tada@eng.u-hyogo.ac.jp; Onoda, Mitsuyoshi

    2010-11-30

    The electrophoretic deposition is a method useful to prepare conjugated polymer films for electronic devices. This method provides high material recovery rate on the substrate from the suspension, in contrast to the conventional spin-coating in which most of the material placed on the substrate is blown away. Although manual reprecipitation technique successfully yields suspensions of various conjugated polymers including polyfluorene derivatives, it is favorable to control the preparation process of suspensions. In this context, this paper reports preliminary results on the preparation of suspension of conjugated polymer by using an ultrasonic atomizer. While the resultant films do not show particular difference due to the preparation methods of the suspension, the electric current profiles during the electrophoretic deposition suggests that the ultrasonic atomization of polymer solution prior to be mixed with poor solvent results in smaller and less uniform colloidal particles than the conventional manual pouring method.

  20. 45 CFR 99.4 - Suspension of rules.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 1 2010-10-01 2010-10-01 false Suspension of rules. 99.4 Section 99.4 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION PROCEDURE FOR HEARINGS FOR THE CHILD CARE AND DEVELOPMENT FUND General § 99.4 Suspension of rules. With notice to all parties, the...

  1. Progressive collapse susceptibility of a long span suspension bridge

    DEFF Research Database (Denmark)

    Olmati, Pierluigi; Giuliani, Luisa

    2013-01-01

    Long span bridges are complex structural systems, often having strategic roles in the network infrastructures; consequently their susceptibility to a disproportionate response in case of local failures needs to be assessed. In particular, current regulations prescribe that the structural robustness...... should be maintained in case of an accidental hanger detachment. Local damages in bridges, which are characterized by an horizontal load transfer system, may progress along the deck or along the suspension system, as the dynamic overloading of the structural elements immediately adjacent to the failed...

  2. Aqueous suspensions of {alpha}Al{sub 2}O{sub 3}/SiC mixed systems

    Energy Technology Data Exchange (ETDEWEB)

    Pagnoux, C.; Baklouti, S.; Chartier, T.; Baumard, J.F. [ENSCI, Limoges (France). LMCTS

    1997-12-31

    The preparation of aqueous {alpha}-Al{sub 2}O{sub 3}, {alpha}-SiO{sub 2} and {alpha}-SiC suspensions with polyelectrolytes, respectively the NH{sub 4}{sup +} salt of polymethacrylic acid (PMA-NH{sub 4}{sup +}) and acidic form polyethylene imine (PEI-H{sup +}) is investigated. It is based on the adsorption of these polyelectrolytes which in turn depends mainly on the nature of the polyelectrolyte, and the charge density which develops on the powder surface in water. Good dispersion and stability of dispersions are then obtained through electrostatic and steric stabilization. As an application, the preparation of an Al{sub 2}O{sub 3}-SiC aqueous mixed slurry was investigated as a preliminary step for processing of Al{sub 2}O{sub 3}/SiC nanocomposites. (orig.) 2 refs.

  3. Modeling and Analysis of Static and Dynamic Characteristics of Nonlinear Seat Suspension for Off-Road Vehicles

    Directory of Open Access Journals (Sweden)

    Zhenhua Yan

    2015-01-01

    Full Text Available Low-frequency vibrations (0.5–5 Hz that harm drivers occur in off-road vehicles. Thus, researchers have focused on finding methods to effectively isolate or control low-frequency vibrations. A novel nonlinear seat suspension structure for off-road vehicles is designed, whose static characteristics and seat-human system dynamic response are modeled and analyzed, and experiments are conducted to verify the theoretical solutions. Results show that the stiffness of this nonlinear seat suspension could achieve real zero stiffness through well-matched parameters, and precompression of the main spring could change the nonlinear seat suspension performance when a driver’s weight changes. The displacement transmissibility curve corresponds with the static characteristic curve of nonlinear suspension, where the middle part of the static characteristic curve is gentler and the resonance frequency of the displacement transmissibility curve and the isolation minimum frequency are lower. Damping should correspond with static characteristics, in which the corresponding suspension damping value should be smaller given a flatter static characteristic curve to prevent vibration isolation performance reduction.

  4. Flight suspension for the relativity gyro

    International Nuclear Information System (INIS)

    Patten, R.A. van

    1983-01-01

    A suspension system for levitation and precision positioning of the niobium coated spherical quartz gyro rotor during orbital flight has been simulated. The system employs multiple controllers and estimators with microprocessor (Z80) controlled range switching. The resulting system handles external accelerations up to 1 g in the highest range yet in the lowest range, below 10 -6 g the sensor noise power spectral density produces only 10 -10 g rms in the rotor. The system is capable of automatic emergency switch up within 100 μsec. Switch down is automatic to expected flight levels of ± 5 x 10 -8 g. Positioning accuracy in all ranges including emergency switch up is ± 5 μin. static, and ± 50 μin. dynamic. The average acceleration during the mission should be 10 -10 g to attain the science data accuracy goal. (Auth.)

  5. Fuzzy logic control of vehicle suspensions with dry friction nonlinearity

    Indian Academy of Sciences (India)

    We design and investigate the performance of fuzzy logic-controlled (FLC) active suspensions on a nonlinear vehicle model with four degrees of freedom, without causing any degeneration in suspension working limits. Force actuators were mounted parallel to the suspensions. In this new approach, linear combinations of ...

  6. 31 CFR 19.605 - How does suspension differ from debarment?

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false How does suspension differ from debarment? 19.605 Section 19.605 Money and Finance: Treasury Office of the Secretary of the Treasury GOVERNMENTWIDE DEBARMENT AND SUSPENSION (NONPROCUREMENT) General Principles Relating to Suspension and Debarment...

  7. 12 CFR 513.4 - Suspension and debarment.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Suspension and debarment. 513.4 Section 513.4 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY PRACTICE BEFORE THE OFFICE § 513.4 Suspension and debarment. (a) The Office may censure any person practicing before it or may deny...

  8. Effective viscosity of 2D suspensions - Confinement effects

    Science.gov (United States)

    Peyla, Philippe; Priem, Stephane; Vincent, Doyeux; Farutin, Alexander; Ismail, Mourad

    2014-11-01

    We study the rheology of a sheared 2D suspension of non-Brownian disks in presence of walls. Although, it is of course possible today with modern computers and powerful algorithms to perform direct numerical simulations that fully account for multiparticle 3D interactions, the analysis of the simple case of a 2D suspension, provides valuable insights and helps to understand 3D results. For instance, we examine the role of particle-wall and particle-particle interactions in determining the rheology of confined sheared suspensions. In addition we evaluate the intrinsic viscosity as well as the contribution of hydrodynamic interactions to the dissipation as a function of a wide range of confinements. Thanks to the direct visualisation of the whole 2D Stokes flow, we are able to give a clear interpretation about the rheology of semi-dilute confined suspensions.

  9. Characterization of Complex Colloidal Suspensions

    Science.gov (United States)

    Seaman, J. C.; Guerin, M.; Jackson, B. P.; Ranville, J. M.

    2003-04-01

    Surface chemical reactions play a major role in controlling contaminant fate and transport in the subsurface environment. Recent field and laboratory evidence suggests that mobile soil and groundwater colloids may facilitate the migration of sparingly soluble groundwater contaminants. Colloidal suspensions collected in the field or generated in laboratory column experiments tend to be fairly dilute in nature and comprised of relatively small particulates (reserved for studying ideal systems to the characterization of mobile colloids. However, many of these analytical techniques, including total/selective dissolution methods, dynamic light scattering, micro-electrophoresis, streaming potential, and even scanning electron microscopy (SEM), can be biased in of larger size fractions, and therefore, extremely sensitive to sampling, storage, and fractionation artifacts. In addition, surface modifiers such as sorbed oxides or organics can alter particulate appearance, composition, and behavior when compared to synthetic analogues or mineral standards. The current presentation will discuss the limitations and inherent biases associated with a number of analytical characterization techniques that are commonly applied to the study of mobile soil and groundwater colloids, including field flow fractionation (FFF) and acoustic based methods that have only recently become available.

  10. Solid lipid nanoparticles suspension versus commercial solutions for dermal delivery of minoxidil.

    Science.gov (United States)

    Padois, Karine; Cantiéni, Céline; Bertholle, Valérie; Bardel, Claire; Pirot, Fabrice; Falson, Françoise

    2011-09-15

    Solid lipid nanoparticles have been reported as possible carrier for skin drug delivery. Solid lipid nanoparticles are produced from biocompatible and biodegradable lipids. Solid lipid nanoparticles made of semi-synthetic triglycerides stabilized with a mixture of polysorbate and sorbitan oleate were loaded with 5% of minoxidil. The prepared systems were characterized for particle size, pH and drug content. Ex vivo skin penetration studies were performed using Franz-type glass diffusion cells and pig ear skin. Ex vivo skin corrosion studies were realized with a method derived from the Corrositex(®) test. Solid lipid nanoparticles suspensions were compared to commercial solutions in terms of skin penetration and skin corrosion. Solid lipid nanoparticles suspensions have been shown as efficient as commercial solutions for skin penetration; and were non-corrosive while commercial solutions presented a corrosive potential. Solid lipid nanoparticles suspensions would constitute a promising formulation for hair loss treatment. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Nanometer-scale sizing accuracy of particle suspensions on an unmodified cell phone using elastic light scattering.

    Science.gov (United States)

    Smith, Zachary J; Chu, Kaiqin; Wachsmann-Hogiu, Sebastian

    2012-01-01

    We report on the construction of a Fourier plane imaging system attached to a cell phone. By illuminating particle suspensions with a collimated beam from an inexpensive diode laser, angularly resolved scattering patterns are imaged by the phone's camera. Analyzing these patterns with Mie theory results in predictions of size distributions of the particles in suspension. Despite using consumer grade electronics, we extracted size distributions of sphere suspensions with better than 20 nm accuracy in determining the mean size. We also show results from milk, yeast, and blood cells. Performing these measurements on a portable device presents opportunities for field-testing of food quality, process monitoring, and medical diagnosis.

  12. Nanodispersed Suspensions of Zeolite Catalysts for Converting Dimethyl Ether into Olefins

    Science.gov (United States)

    Kolesnichenko, N. V.; Yashina, O. V.; Ezhova, N. N.; Bondarenko, G. N.; Khadzhiev, S. N.

    2018-01-01

    Nanodispersed suspensions that are effective in DME conversion and stable in the reaction zone in a three-phase system (slurry reactor) are obtained from MFI zeolite commercial samples (TsVM, IK-17-1, and CBV) in liquid media via ultrasonic treatment (UST). It is found that the dispersion medium, in which ultrasound affects zeolite commercial sample, has a large influence on particle size in the suspension. UST in the aqueous medium produces zeolite nanoparticles smaller than 50 nm, while larger particles of MFI zeolite samples form in silicone or hydrocarbon oils. Spectral and adsorption data show that when zeolites undergo UST in an aqueous medium, the acid sites are redistributed on the zeolite surface and the specific surface area of the mesopores increases. Preliminary UST in aqueous media of zeolite commercial samples (TsVM, IK-17-1, and CBV) affects the catalytic properties of MFI zeolite nanodispersed suspensions. The selectivity of samples when paraffins and olefins form is largely due to superacid sites consisting of OH groups of hydroxonium ion H3O+.

  13. 21 CFR 520.1182 - Iron dextran suspension.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Iron dextran suspension. 520.1182 Section 520.1182... DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.1182 Iron dextran suspension... hydroxide in complex with a low molecular weight dextran. (b) Sponsor. See No. 051311 in § 510.600(c) of...

  14. Non-linear dielectric spectroscopy of microbiological suspensions

    Science.gov (United States)

    Treo, Ernesto F; Felice, Carmelo J

    2009-01-01

    Background Non-linear dielectric spectroscopy (NLDS) of microorganism was characterized by the generation of harmonics in the polarization current when a microorganism suspension was exposed to a sinusoidal electric field. The biological nonlinear response initially described was not well verified by other authors and the results were susceptible to ambiguous interpretation. In this paper NLDS was performed to yeast suspension in tripolar and tetrapolar configuration with a recently developed analyzer. Methods Tripolar analysis was carried out by applying sinusoidal voltages up to 1 V at the electrode interface. Tetrapolar analysis was carried on with sinusoidal field strengths from 0.1 V cm-1 to 70 V cm-1. Both analyses were performed within a frequency range from 1 Hz through 100 Hz. The harmonic amplitudes were Fourier-analyzed and expressed in dB. The third harmonic, as reported previously, was investigated. Statistical analysis (ANOVA) was used to test the effect of inhibitor an activator of the plasma membrane enzyme in the measured response. Results No significant non-linearities were observed in tetrapolar analysis, and no observable changes occurred when inhibitor and activator were added to the suspension. Statistical analysis confirmed these results. When a pure sinus voltage was applied to an electrode-yeast suspension interface, variations higher than 25 dB for the 3rd harmonic were observed. Variation higher than 20 dB in the 3rd harmonics has also been found when adding an inhibitor or activator of the membrane-bounded enzymes. These variations did not occur when the suspension was boiled. Discussion The lack of result in tetrapolar cells suggest that there is no, if any, harmonic generation in microbiological bulk suspension. The non-linear response observed was originated in the electrode-electrolyte interface. The frequency and voltage windows observed in previous tetrapolar analysis were repeated in the tripolar measurements, but maximum were not

  15. Non-linear dielectric spectroscopy of microbiological suspensions

    Directory of Open Access Journals (Sweden)

    Felice Carmelo J

    2009-09-01

    Full Text Available Abstract Background Non-linear dielectric spectroscopy (NLDS of microorganism was characterized by the generation of harmonics in the polarization current when a microorganism suspension was exposed to a sinusoidal electric field. The biological nonlinear response initially described was not well verified by other authors and the results were susceptible to ambiguous interpretation. In this paper NLDS was performed to yeast suspension in tripolar and tetrapolar configuration with a recently developed analyzer. Methods Tripolar analysis was carried out by applying sinusoidal voltages up to 1 V at the electrode interface. Tetrapolar analysis was carried on with sinusoidal field strengths from 0.1 V cm-1 to 70 V cm-1. Both analyses were performed within a frequency range from 1 Hz through 100 Hz. The harmonic amplitudes were Fourier-analyzed and expressed in dB. The third harmonic, as reported previously, was investigated. Statistical analysis (ANOVA was used to test the effect of inhibitor an activator of the plasma membrane enzyme in the measured response. Results No significant non-linearities were observed in tetrapolar analysis, and no observable changes occurred when inhibitor and activator were added to the suspension. Statistical analysis confirmed these results. When a pure sinus voltage was applied to an electrode-yeast suspension interface, variations higher than 25 dB for the 3rd harmonic were observed. Variation higher than 20 dB in the 3rd harmonics has also been found when adding an inhibitor or activator of the membrane-bounded enzymes. These variations did not occur when the suspension was boiled. Discussion The lack of result in tetrapolar cells suggest that there is no, if any, harmonic generation in microbiological bulk suspension. The non-linear response observed was originated in the electrode-electrolyte interface. The frequency and voltage windows observed in previous tetrapolar analysis were repeated in the tripolar

  16. Optimization of Casting Design Parameters on Fabrication of Reliable Semi-Solid Aluminum Suspension Control Arm

    Science.gov (United States)

    Ragab, Kh. A.; Bouaicha, A.; Bouazara, M.

    2017-09-01

    The semi-solid casting process has the advantage of providing reliable mechanical aluminum parts that work continuously in dynamic as control arm of the suspension system in automotive vehicles. The quality performance of dynamic control arm is related to casting mold and gating system designs that affect the fluidity of semi-solid metal during filling the mold. Therefore, this study focuses on improvement in mechanical performance, depending on material characterization, and casting design optimization, of suspension control arms made of A357 aluminum semi-solid alloys. Mechanical and design analyses, applied on the suspension arm, showed the occurrence of mechanical failures at unexpected weak points. Metallurgical analysis showed that the main reason lies in the difficult flow of semi-solid paste through the thin thicknesses of a complex geometry. A design modification procedure is applied to the geometry of the suspension arm to avoid this problem and to improve its quality performance. The design modification of parts was carried out by using SolidWorks design software, evaluation of constraints with ABAQUS, and simulation of flow with ProCast software. The proposed designs showed that the modified suspension arm, without ribs and with a central canvas designed as Z, is considered as a perfect casting design showing an increase in the structural strength of the component. In this case, maximum von Mises stress is 199 MPa that is below the yield strength of the material. The modified casting mold design shows a high uniformity and minim turbulence of molten metal flow during semi-solid casting process.

  17. 17 CFR 240.12d2-1 - Suspension of trading.

    Science.gov (United States)

    2010-04-01

    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Suspension of trading. 240... Securities Exchange Act of 1934 Suspension of Trading, Withdrawal, and Striking from Listing and Registration § 240.12d2-1 Suspension of trading. (a) A national securities exchange may suspend from trading a...

  18. Effects of transients in LIGO suspensions on searches for gravitational waves.

    Science.gov (United States)

    Walker, M; Abbott, T D; Aston, S M; González, G; Macleod, D M; McIver, J; Abbott, B P; Abbott, R; Adams, C; Adhikari, R X; Anderson, S B; Ananyeva, A; Appert, S; Arai, K; Ballmer, S W; Barker, D; Barr, B; Barsotti, L; Bartlett, J; Bartos, I; Batch, J C; Bell, A S; Betzwieser, J; Billingsley, G; Birch, J; Biscans, S; Biwer, C; Blair, C D; Bork, R; Brooks, A F; Ciani, G; Clara, F; Countryman, S T; Cowart, M J; Coyne, D C; Cumming, A; Cunningham, L; Danzmann, K; Da Silva Costa, C F; Daw, E J; DeBra, D; DeRosa, R T; DeSalvo, R; Dooley, K L; Doravari, S; Driggers, J C; Dwyer, S E; Effler, A; Etzel, T; Evans, M; Evans, T M; Factourovich, M; Fair, H; Fernández Galiana, A; Fisher, R P; Fritschel, P; Frolov, V V; Fulda, P; Fyffe, M; Giaime, J A; Giardina, K D; Goetz, E; Goetz, R; Gras, S; Gray, C; Grote, H; Gushwa, K E; Gustafson, E K; Gustafson, R; Hall, E D; Hammond, G; Hanks, J; Hanson, J; Hardwick, T; Harry, G M; Heintze, M C; Heptonstall, A W; Hough, J; Izumi, K; Jones, R; Kandhasamy, S; Karki, S; Kasprzack, M; Kaufer, S; Kawabe, K; Kijbunchoo, N; King, E J; King, P J; Kissel, J S; Korth, W Z; Kuehn, G; Landry, M; Lantz, B; Lockerbie, N A; Lormand, M; Lundgren, A P; MacInnis, M; Márka, S; Márka, Z; Markosyan, A S; Maros, E; Martin, I W; Martynov, D V; Mason, K; Massinger, T J; Matichard, F; Mavalvala, N; McCarthy, R; McClelland, D E; McCormick, S; McIntyre, G; Mendell, G; Merilh, E L; Meyers, P M; Miller, J; Mittleman, R; Moreno, G; Mueller, G; Mullavey, A; Munch, J; Nuttall, L K; Oberling, J; Oliver, M; Oppermann, P; Oram, Richard J; O'Reilly, B; Ottaway, D J; Overmier, H; Palamos, J R; Paris, H R; Parker, W; Pele, A; Penn, S; Phelps, M; Pierro, V; Pinto, I; Principe, M; Prokhorov, L G; Puncken, O; Quetschke, V; Quintero, E A; Raab, F J; Radkins, H; Raffai, P; Reid, S; Reitze, D H; Robertson, N A; Rollins, J G; Roma, V J; Romie, J H; Rowan, S; Ryan, K; Sadecki, T; Sanchez, E J; Sandberg, V; Savage, R L; Schofield, R M S; Sellers, D; Shaddock, D A; Shaffer, T J; Shapiro, B; Shawhan, P; Shoemaker, D H; Sigg, D; Slagmolen, B J J; Smith, B; Smith, J R; Sorazu, B; Staley, A; Strain, K A; Tanner, D B; Taylor, R; Thomas, M; Thomas, P; Thorne, K A; Thrane, E; Torrie, C I; Traylor, G; Tuyenbayev, D; Vajente, G; Valdes, G; van Veggel, A A; Vecchio, A; Veitch, P J; Venkateswara, K; Vo, T; Vorvick, C; Ward, R L; Warner, J; Weaver, B; Weiss, R; Weßels, P; Willke, B; Wipf, C C; Worden, J; Wu, G; Yamamoto, H; Yancey, C C; Yu, Hang; Yu, Haocun; Zhang, L; Zucker, M E; Zweizig, J

    2017-12-01

    This paper presents an analysis of the transient behavior of the Advanced LIGO (Laser Interferometer Gravitational-wave Observatory) suspensions used to seismically isolate the optics. We have characterized the transients in the longitudinal motion of the quadruple suspensions during Advanced LIGO's first observing run. Propagation of transients between stages is consistent with modeled transfer functions, such that transient motion originating at the top of the suspension chain is significantly reduced in amplitude at the test mass. We find that there are transients seen by the longitudinal motion monitors of quadruple suspensions, but they are not significantly correlated with transient motion above the noise floor in the gravitational wave strain data, and therefore do not present a dominant source of background noise in the searches for transient gravitational wave signals. Using the suspension transfer functions, we compared the transients in a week of gravitational wave strain data with transients from a quadruple suspension. Of the strain transients between 10 and 60 Hz, 84% are loud enough that they would have appeared above the sensor noise in the top stage quadruple suspension monitors if they had originated at that stage at the same frequencies. We find no significant temporal correlation with the suspension transients in that stage, so we can rule out suspension motion originating at the top stage as the cause of those transients. However, only 3.2% of the gravitational wave strain transients are loud enough that they would have been seen by the second stage suspension sensors, and none of them are above the sensor noise levels of the penultimate stage. Therefore, we cannot eliminate the possibility of transient noise in the detectors originating in the intermediate stages of the suspension below the sensing noise.

  19. 12 CFR 263.404 - Notice of removal, suspension, or debarment.

    Science.gov (United States)

    2010-01-01

    ... accountants and firms. An accountant or accounting firm that provides audit services to a banking organization... 12 Banks and Banking 3 2010-01-01 2010-01-01 false Notice of removal, suspension, or debarment. 263.404 Section 263.404 Banks and Banking FEDERAL RESERVE SYSTEM (CONTINUED) BOARD OF GOVERNORS OF THE...

  20. Phase behaviour and dynamics of suspensions of hard colloidal platelets

    NARCIS (Netherlands)

    Kooij, F.M. van der

    2000-01-01

    In this thesis we aim to provide a many-sided answer to the question: what are the consequences of plate-like colloidal shape on a suspensions' physical properties? A central role in this investigation is played by the experimental model system of platelets which, building on the Van 't Hoff