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

NASA Astrophysics Data System (ADS)

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.

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

ERIC Educational Resources Information Center

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…

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

NASA Astrophysics Data System (ADS)

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.

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

DOEpatents

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.

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

DOEpatents

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.

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

DOEpatents

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

1992-01-01

This report discusses a propulsion and stabilization system comprising a series of figure 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 figure 8 coils either longitudinally and/or vertically with resulting changes in the propulsion, the vertical stability, and the suspension.

Improved design of dynamic vibration absorber by using the inerter and its application in vehicle suspension

NASA Astrophysics Data System (ADS)

Shen, Yujie; Chen, Long; Yang, Xiaofeng; Shi, Dehua; Yang, Jun

2016-01-01

Inerter is a recently proposed mechanical element with two terminals. The novelty of this paper is to present the improved design which aims to add traditional dynamic vibration absorber to the vehicle body by using the inerter. Based on this background, a new vehicle suspension structure called ISD suspension, including the inerter, spring and damper has been created. A dual-mass vibration model including the ISD suspension is considered in this study. Parameters are obtained by using the genetic optimizing algorithm. The frequency-domain simulation confirms that the ISD suspension can effectively improve the damping performance of the suspension system, especially at the offset frequency of the vehicle body, which is consistent with the feature of the dynamic vibration absorber added to the vehicle body mass. At last, a prototype ball screw inerter has been designed and the bench test of a quarter-car model has been undertaken. Under the conditions of the random road input, the vehicle ride comfort evaluation of body acceleration RMS value decreases by 4% at most, the suspension deflection RMS value decreases by 16% at most, the tire dynamic load RMS value decreases by 6% at most. Power spectral density results also indicate that the ISD suspension has superior damping performance than passive suspension which proves that the proposed ISD suspension is deemed effective.

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

NASA Astrophysics Data System (ADS)

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.

Adaptive super-twisting observer for estimation of random road excitation profile in automotive suspension systems.

PubMed

Rath, J J; Veluvolu, K C; Defoort, M

2014-01-01

The estimation of road excitation profile is important for evaluation of vehicle stability and vehicle suspension performance for autonomous vehicle control systems. In this work, the nonlinear dynamics of the active automotive system that is excited by the unknown road excitation profile are considered for modeling. To address the issue of estimation of road profile, we develop an adaptive supertwisting observer for state and unknown road profile estimation. Under Lipschitz conditions for the nonlinear functions, the convergence of the estimation error is proven. Simulation results with Ford Fiesta MK2 demonstrate the effectiveness of the proposed observer for state and unknown input estimation for nonlinear active suspension system.

Adaptive Super-Twisting Observer for Estimation of Random Road Excitation Profile in Automotive Suspension Systems

PubMed Central

Rath, J. J.; Veluvolu, K. C.; Defoort, M.

2014-01-01

The estimation of road excitation profile is important for evaluation of vehicle stability and vehicle suspension performance for autonomous vehicle control systems. In this work, the nonlinear dynamics of the active automotive system that is excited by the unknown road excitation profile are considered for modeling. To address the issue of estimation of road profile, we develop an adaptive supertwisting observer for state and unknown road profile estimation. Under Lipschitz conditions for the nonlinear functions, the convergence of the estimation error is proven. Simulation results with Ford Fiesta MK2 demonstrate the effectiveness of the proposed observer for state and unknown input estimation for nonlinear active suspension system. PMID:24683321

US Marine Corps assault amphibious vehicle suspension system analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hammonds, C.J.; Jones, J.K.; Mayhall, J.A.

1988-11-01

In response to a request from the US Marine Corps (USMC), the Oak Ridge National Laboratory investigated a problem with the suspension system of the assault amphibious vehicle (AAV), Personnel Model 7A1. In the course of the investigation, drawings of the AAV and field survey data on bearing failures provided by VSE Corporation were used. The analysis approach taken was to model the suspension system and the vehicle hull and support structure using finite element techniques. This provided stress and deflection information for the system. To determine the loads imparted to the system as the AAV traversed terrain features, amore » dynamics model was developed to provide loads to the finite element analysis (FEA). Because the primary indication of a problem was frequent suspension-system bearing failure, an analysis of the suspension-system bearings was conducted. Finally, to check the accuracy of the models and to provide actual load data for bearing analysis, an instrumented AAV was tested over a surveyed course at Camp Pendleton, California. Initially the dynamics model assumed the interface between the hull and the suspension system to be fixed. Later improvements incorporating the flexibility of the vehicle hull into the analysis by linking the two models resulted in improved accuracy. Actual measurements of the front road-arm displacement and vertical acceleration of the chassis are compared with predictions from the model. The correlation is quite good and indicates that the model can accurately predict the dynamic load on each road wheel for input into finite element analyses. The dynamics model can be expanded to study the effects of adding weight to the vehicle, traversing other terrains, or evaluating inputs such as weapons firing or drop tests. 7 refs., 75 figs., 10 tabs.« less

Analysis of Rail Vehicle Suspension Spring with Special Emphasis on Curving, Tracking and Tractive Efforts

NASA Astrophysics Data System (ADS)

Kumbhalkar, M. A.; Bhope, D. V.; Vanalkar, A. V.

2016-09-01

The dynamics of the rail vehicle represents a balance between the forces acting between wheel and rail, the inertia forces and the forces exerted by suspension and articulation. Axial loading on helical spring causes vertical deflection at straight track but failures calls to investigate for lateral and longitudinal loading at horizontal and vertical curves respectively. Goods carrying vehicle has the frequent failures of middle axle inner suspension spring calls for investigation. The springs are analyzed for effect of stress concentration due to centripetal force and due to tractive and breaking effort. This paper also discusses shear failure analysis of spring at curvature and at uphill at various speeds for different loading condition analytically and by finite element analysis. Two mass rail vehicle suspension systems have been analyzed for vibration responses analytically using mathematical tool Matlab Simulink and the same will be evaluated using FFT vibration analyzer to find peak resonance in vertical, lateral and longitudinal direction. The results prove that the suspension acquires high repeated load in vertical and lateral direction due to tracking and curving causes maximum stress concentration on middle axle suspension spring as height of this spring is larger than end axle spring in primary suspension system and responsible for failure of middle axle suspension spring due to high stress acquisition.

Semi-active control of tracked vehicle suspension incorporating magnetorheological dampers

NASA Astrophysics Data System (ADS)

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.

Study on the Vehicle Dynamic Load Considering the Vehicle-Pavement Coupled Effect

NASA Astrophysics Data System (ADS)

Xu, H. L.; He, L.; An, D.

2017-11-01

The vibration of vehicle-pavement interaction system is sophisticated random vibration process and the vehicle-pavement coupled effect was not considered in the previous study. A new linear elastic model of the vehicle-pavement coupled system was established in the paper. The new model was verified with field measurement which could reflect the real vibration between vehicle and pavement. Using the new model, the study on the vehicle dynamic load considering the vehicle-pavement coupled effect showed that random forces (centralization) between vehicle and pavement were influenced largely by vehicle-pavement coupled effect. Numerical calculation indicated that the maximum of random forces in coupled model was 2.4 times than that in uncoupled model. Inquiring the reason, it was found that the main vibration frequency of the vehicle non-suspension system was similar with that of the vehicle suspension system in the coupled model and the resonance vibration lead to vehicle dynamic load increase significantly.

Dynamics and controls in maglev systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cai, Y.; Chen, S.S.; Rote, D.M.

1992-09-01

The dynamic response of magnetically levitated (maglev) ground transportation systems has important consequences for safety and ride quality, guideway design, and system costs. Ride quality is determined by vehicle response and by environmental factors such as humidity and noise. The dynamic response of the vehicles is the key element in determining ride quality, and vehicle stability is an important safety-related element. To design a proper guideway that provides acceptable ride quality in the stable region, vehicle dynamics must be understood. Furthermore the trade-off between guideway smoothness and the levitation and control systems must be considered if maglev systems are tomore » be economically feasible. The link between the guideway and the other maglev components is vehicle dynamics. For a commercial maglev system, vehicle dynamics must be analyzed and tested in detail. In this study, the role of dynamics and controls in maglev vehicle/guideway interactions is discussed, and the literature on modeling the dynamic interactions of vehicle/guideway and suspension controls for ground vehicles is reviewed. Particular emphasis is placed on modeling vehicle/guideway interactions and response characteristics of maglev systems for a multicar, multiload vehicle traveling on a single- or doublespan flexible guideway, including coupling effects of vehicle/guideway, comparison of concentrated and distributed loads, and ride comfort. Different control-law designs are introduced into vehicle suspensions when a simple two-degree-of-freedom vehicle model is applied. Active and semiactive control designs for primary and secondary suspensions do improve the response of vehicle and provide acceptable ride comfort. Finally, future research associated with dynamics and controls of vehicle/guideway systems is identified.« less

Numerical simulation of active track tensioning system for autonomous hybrid vehicle

NASA Astrophysics Data System (ADS)

Mȩżyk, Arkadiusz; Czapla, Tomasz; Klein, Wojciech; Mura, Gabriel

2017-05-01

One of the most important components of a high speed tracked vehicle is an efficient suspension system. The vehicle should be able to operate both in rough terrain for performance of engineering tasks as well as on the road with high speed. This is especially important for an autonomous platform that operates either with or without human supervision, so that the vibration level can rise compared to a manned vehicle. In this case critical electronic and electric parts must be protected to ensure the reliability of the vehicle. The paper presents a dynamic parameters determination methodology of suspension system for an autonomous high speed tracked platform with total weight of about 5 tonnes and hybrid propulsion system. Common among tracked vehicles suspension solutions and cost-efficient, the torsion-bar system was chosen. One of the most important issues was determining optimal track tensioning - in this case an active hydraulic system was applied. The selection of system parameters was performed with using numerical model based on multi-body dynamic approach. The results of numerical analysis were used to define parameters of active tensioning control system setup. LMS Virtual.Lab Motion was used for multi-body dynamics numerical calculation and Matlab/SIMULINK for control system simulation.

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

NASA Astrophysics Data System (ADS)

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.

Total dynamic response of a PSS vehicle negotiating asymmetric road excitations

NASA Astrophysics Data System (ADS)

Zhu, Jian Jun; Khajepour, Amir; Esmailzadeh, Ebrahim

2012-12-01

A planar suspension system (PSS) is a novel automobile suspension system in which an individual spring-damper strut is implemented in both the vertical and longitudinal directions, respectively. The wheels in a vehicle with such a suspension system can move back and forth relative to the chassis. When a PSS vehicle experiences asymmetric road excitations, the relative longitudinal motion of wheels with respect to the chassis in two sides of the same axle are not identical, and thus the two wheels at one axle will not be aligned in the same axis. The total dynamic responses, including those of the bounce, pitch and the roll of the PSS vehicle, to the asymmetric road excitation may exhibit different characteristics from those of a conventional vehicle. This paper presents an investigation into the comprehensive dynamic behaviour of a vehicle with the PSS, in such a road condition, on both the straight and curved roads. The study was carried out using an 18 DOF full-car model incorporating a radial-spring tyre-ground contact model and a 2D tyre-ground dynamic friction model. Results demonstrate that the total dynamic behaviour of a PSS vehicle is generally comparable with that of the conventional vehicle, while PSS exhibits significant improvement in absorbing the impact forces along the longitudinal direction when compared to the conventional suspension system. The PSS vehicle is found to be more stable than the conventional vehicle in terms of the directional performance against the disturbance of the road potholes on a straight line manoeuvre, while exhibiting a very similar handling performance on a curved line.

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

NASA Astrophysics Data System (ADS)

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.

Design and analysis of a shock absorber with variable moment of inertia for passive vehicle suspensions

NASA Astrophysics Data System (ADS)

Xu, Tongyi; Liang, Ming; Li, Chuan; Yang, Shuai

2015-10-01

A two-terminal mass (TTM) based vibration absorber with variable moment of inertia (VMI) for passive vehicle suspension is proposed. The VMI of the system is achieved by the motion of sliders embedded in a hydraulic driven flywheel. The moment of inertia increases in reaction to strong vertical vehicle oscillations and decreases for weak vertical oscillations. The hydraulic mechanism of the system converts the relative linear motion between the two terminals of the suspension into rotating motion of the flywheel. In the case of stronger vehicle vertical oscillation, the sliders inside the flywheel move away from the center of the flywheel because of the centrifugal force, hence yielding higher moment of inertia. The opposite is true in the case of weaker vehicle oscillation. As such, the moment of inertia adjusts itself adaptively in response to the road conditions. The performance of the proposed TTM-VMI absorber has been analyzed via dynamics modeling and simulation and further examined by experiments. In comparison to its counterpart with constant moment of inertia, the proposed VMI system offers faster response, better road handling and safety, improved ride comfort, and reduced suspension deflection except in the case of sinusoidal excitations.

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

NASA Astrophysics Data System (ADS)

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.

49 CFR 570.1 - Scope.

Code of Federal Regulations, 2010 CFR

2010-10-01

... systems, steering and suspension systems, and tire and wheel assemblies of motor vehicles in use. ... OF TRANSPORTATION VEHICLE IN USE INSPECTION STANDARDS Vehicles With GVWR of 10,000 Pounds or Less...

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

NASA Astrophysics Data System (ADS)

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.

Using the lead vehicle as preview sensor in convoy vehicle active suspension control

NASA Astrophysics Data System (ADS)

Rahman, Mustafizur; Rideout, Geoff

2012-12-01

Both ride quality and roadholding of actively suspended vehicles can be improved by sensing the road ahead of the vehicle and using this information in a preview controller. Previous applications have used look-ahead sensors mounted on the front bumper to measure terrain beneath. Such sensors are vulnerable, potentially confused by water, snow, or other soft obstacles and offer a fixed preview time. For convoy vehicle applications, this paper proposes using the overall response of the preceding vehicle(s) to generate preview controller information for follower vehicles. A robust observer is used to estimate the states of a quarter-car vehicle model, from which road profile is estimated and passed on to the follower vehicle(s) to generate a preview function. The preview-active suspension, implemented in discrete time using a shift register approach to improve simulation time, reduces sprung mass acceleration and dynamic tyre deflection peaks by more than 50% and 40%, respectively. Terrain can change from one vehicle to the next if a loose obstacle is dislodged, or if the vehicle paths are sufficiently different so that one vehicle misses a discrete road event. The resulting spurious preview information can give suspension performance worse than that of a passive or conventional active system. In this paper, each vehicle can effectively estimate the road profile based on its own state trajectory. By comparing its own road estimate with the preview information, preview errors can be detected and suspension control quickly switched from preview to conventional active control to preserve performance improvements compared to passive suspensions.

Active control of an innovative seat suspension system with acceleration measurement based friction estimation

NASA Astrophysics Data System (ADS)

Ning, Donghong; Sun, Shuaishuai; Li, Hongyi; Du, Haiping; Li, Weihua

2016-12-01

In this paper, an innovative active seat suspension system for vehicles is presented. This seat suspension prototype is built with two low cost actuators each of which has one rotary motor and one gear reducer. A H∞ controller with friction compensation is designed for the seat suspension control system where the friction is estimated and compensated based on the measurement of seat acceleration. This principal aim of this research was to control the low frequency vibration transferred or amplified by the vehicle (chassis) suspension, and to maintain the passivity of the seat suspension at high frequency (isolation vibration) while taking into consideration the trade-off between the active seat suspension cost and its high frequency performance. Sinusoidal excitations of 1-4.5 Hz were applied to test the active seat suspension both when controlled and when uncontrolled and this is compared with a well-tuned passive heavy duty vehicle seat suspension. The results indicate the effectiveness of the proposed control algorithm within the tested frequencies. Further tests were conducted using the excitations generated from a quarter-car model under bump and random road profiles. The bump road tests indicate the controlled active seat suspension has good transient response performance. The Power Spectral Density (PSD) method and ISO 2631-1 standards were applied to analyse the seat suspension's acceleration under random road conditions. Although some low magnitude and high frequency noise will inevitably be introduced by the active system, the weighted-frequency Root Mean Square (RMS) acceleration shows that this may not have a large effect on ride comfort. In fact, the ride comfort is improved from being an 'a little uncomfortable' to a 'not uncomfortable' level when compared with the well-tuned passive seat suspension. This low cost active seat suspension design and the proposed controller with the easily measured feedback signals are very practical for real applications.

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

PubMed

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.

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

NASA Astrophysics Data System (ADS)

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.

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

NASA Astrophysics Data System (ADS)

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.

Decoupling suspension controller based on magnetic flux feedback.

PubMed

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.

Decoupling Suspension Controller Based on Magnetic Flux Feedback

PubMed Central

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. PMID:23844415

49 CFR 570.51 - Scope.

Code of Federal Regulations, 2010 CFR

2010-10-01

... suspension systems, and tire and wheel assemblies, of motor vehicles in use with a gross vehicle weight... OF TRANSPORTATION VEHICLE IN USE INSPECTION STANDARDS Vehicles With GVWR of More Than 10,000 Pounds...

Robustness analysis of bogie suspension components Pareto optimised values

NASA Astrophysics Data System (ADS)

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.

Propulsion and stabilization system for magnetically levitated vehicles

DOEpatents

Coffey, Howard T.

1993-06-29

A propulsion and stabilization system for an inductive repulsion type magnetically levitated vehicle which is propelled and stabilized by a system which includes propulsion windings mounted above and parallel to vehicle-borne suspension magnets. A linear synchronous motor is part of the vehicle guideway and is mounted above and parallel to superconducting magnets attached to the magnetically levitated vehicle.

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

PubMed Central

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. PMID:27351020

Lightweight Vehicle and Driver’s Whole-Body Models for Vibration Analysis

NASA Astrophysics Data System (ADS)

MdSah, Jamali; Taha, Zahari; Azwan Ismail, Khairul

2018-03-01

Vehicle vibration is a main factor for driving fatigue, discomfort and health problems. The ability to simulate the vibration characteristics in the vehicle and its effects on driver’s whole-body vibration will give significant advantages to designers especially on the vehicle development time and cost. However, it is difficult to achieve optimal condition of ride comfort and handling when using passive suspension system. This paper presents mathematical equations that can be used to describe the vibration characteristics of a lightweight electric vehicle that had been developed. The vehicle’s model was combined with the lumped-parameter model of driver to determine the whole-body vibration level when the vehicle is passing over a road hump using Matlab Simulink. The models were simulated at a constant speed and the results were compared with the experimental data. The simulated vibration level at the vehicle floor and seat were almost similar to the experimental vibration results. The suspension systems that are being used for the solar vehicle are able to reduce the vibration level due to the road hump. The models can be used to simulate and choose the optimal parameters for the suspensions.

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

NASA Astrophysics Data System (ADS)

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.

Computer program for investigating effects of nonlinear suspension-system elastic properties on parachute inflation loads and motions

NASA Technical Reports Server (NTRS)

Poole, L. R.

1972-01-01

A computer program is presented by which the effects of nonlinear suspension-system elastic characteristics on parachute inflation loads and motions can be investigated. A mathematical elastic model of suspension-system geometry is coupled to the planar equations of motion of a general vehicle and canopy. Canopy geometry and aerodynamic drag characteristics and suspension-system elastic properties are tabular inputs. The equations of motion are numerically integrated by use of an equivalent fifth-order Runge-Kutta technique.

Vehicle height and posture control of the electronic air suspension system using the hybrid system approach

NASA Astrophysics Data System (ADS)

Sun, Xiaoqiang; Cai, Yingfeng; Chen, Long; Liu, Yanling; Wang, Shaohua

2016-03-01

The electronic air suspension (EAS) system can improve ride comfort, fuel economy and handling safety of vehicles by adjusting vehicle height. This paper describes the development of a novel controller using the hybrid system approach to adjust the vehicle height (height control) and to regulate the roll and pitch angles of the vehicle body during the height adjustment process (posture control). The vehicle height adjustment system of EAS poses challenging hybrid control problems, since it features different discrete modes of operation, where each mode has an associated linear continuous-time dynamic. In this paper, we propose a novel approach to the modelling and controller design problem for the vehicle height adjustment system of EAS. The system model is described firstly in the hybrid system description language (HYSDEL) to obtain a mixed logical dynamical (MLD) hybrid model. For the resulting model, a hybrid model predictive controller is tuned to improve the vehicle height and posture tracking accuracy and to achieve the on-off statuses direct control of solenoid valves. The effectiveness and performance of the proposed approach are demonstrated by simulations and actual vehicle tests.

Articulated suspension system

NASA Technical Reports Server (NTRS)

Bickler, Donald B. (Inventor)

1989-01-01

The invention provides a rough terrain vehicle which maintains a substantially constant weight, and therefore traction, on all wheels, despite one wheel moving considerably higher or lower than the others, while avoiding a very soft spring suspension. The vehicle includes a chassis or body to be supported and a pair of side suspensions at either side of the body. In a six wheel vehicle, each side suspension includes a middle wheel, and front and rear linkages respectively coupling the front and rear wheels to the middle wheel. A body link pivotally connects the front and rear linkages together, with the middle of the body link rising or falling by only a fraction of the rise or fall of any of the three wheels. The body link pivotally supports the middle of the length of the body. A transverse suspension for suspending the end of the body on the side suspensions includes a middle part pivotally connected to the body about a longitudinal axis and opposite ends each pivotally connected to one of the side suspensions along at least a longitudinal axis.

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

PubMed

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 < 0.0001) as compared to the passive vertical suspension (10%; p's < 0.11). The passive fore-aft (x-axis) and lateral (y-axis) 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 < 0.02). These results indicate that there is a critical need to develop more effective engineering controls including better seat 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.

Adaptive control of nonlinear uncertain active suspension systems with prescribed performance.

PubMed

Huang, Yingbo; Na, Jing; Wu, Xing; Liu, Xiaoqin; Guo, Yu

2015-01-01

This paper proposes adaptive control designs for vehicle active suspension systems with unknown nonlinear dynamics (e.g., nonlinear spring and piece-wise linear damper dynamics). An adaptive control is first proposed to stabilize the vertical vehicle displacement and thus to improve the ride comfort and to guarantee other suspension requirements (e.g., road holding and suspension space limitation) concerning the vehicle safety and mechanical constraints. An augmented neural network is developed to online compensate for the unknown nonlinearities, and a novel adaptive law is developed to estimate both NN weights and uncertain model parameters (e.g., sprung mass), where the parameter estimation error is used as a leakage term superimposed on the classical adaptations. To further improve the control performance and simplify the parameter tuning, a prescribed performance function (PPF) characterizing the error convergence rate, maximum overshoot and steady-state error is used to propose another adaptive control. The stability for the closed-loop system is proved and particular performance requirements are analyzed. Simulations are included to illustrate the effectiveness of the proposed control schemes. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Stochastic optimal control of non-stationary response of a single-degree-of-freedom vehicle model

NASA Astrophysics Data System (ADS)

Narayanan, S.; Raju, G. V.

1990-09-01

An active suspension system to control the non-stationary response of a single-degree-of-freedom (sdf) vehicle model with variable velocity traverse over a rough road is investigated. The suspension is optimized with respect to ride comfort and road holding, using stochastic optimal control theory. The ground excitation is modelled as a spatial homogeneous random process, being the output of a linear shaping filter to white noise. The effect of the rolling contact of the tyre is considered by an additional filter in cascade. The non-stationary response with active suspension is compared with that of a passive system.

Stability of an Alcohol-free, Dye-free Hydrocortisone (2 mg/mL) Compounded Oral Suspension.

PubMed

Manchanda, Arushi; Laracy, Melissa; Savji, Taslim; Bogner, Robin H

2018-01-01

The stability of hydrocortisone in a commercially available dye-free oral vehicle was monitored to establish a beyond-use date for hydrocortisone oral suspension 2 mg/mL. Hydrocortisone oral suspension (2 mg/mL) was prepared from 10-mg tablets in a dye-free oral vehicle (Oral Mix, Medisca) and stored at 4°C and 25°C for 90 days in amber, plastic prescription bottles and oral syringes. The suspendability and dose repeatability of the oral suspension were evaluated. The solubility of hydrocortisone in the dye-free vehicle was determined. Over 90 days, pH and concentration of hydrocortisone in the oral suspension were measured. The stability-indicating nature of a high-pressure liquid chromatographic assay was evaluated in detail. The solubility of hydrocortisone in the dye-free vehicle was 230 mcg/mL at 25°C. This means that about 90% of the drug remains in the solid state where it is less susceptible to degradation. The preparation suspended well to support dose repeatability. The chromatographic assay resolved hydrocortisone from cortisone, excipients in the vehicle, and all degradation products. The assay passed United States Pharmacopeia system suitability tests. Hydrocortisone oral suspension (2 mg/mL) compounded using a dye-free, alcohol-free oral vehicle, Oral Mix, was stable in amber plastic bottles and syringes stored at 4°C and 25°C for 90 days within a 95% confidence interval. Copyright© by International Journal of Pharmaceutical Compounding, Inc.

Base Vehicle Equipment, Special Vehicle, General Purpose Vehicle, and Vehicle Body Mechanics Career Ladders, AFSs 472X0, 472X1A/B/C/D, 472X2 and 472X3.

DTIC Science & Technology

1982-08-01

brakes , belts, and carburetors; servicing air cleaners, oil systems , and drive belts; and lubricating vehicles. Although the six distinct jobs...vehicle systems . General Repair Mechanics repaired, inspected, serviced, and maintained electrical, brake , suspension, and other vehicle systems . This...installing intake or exhaust manifolds removing or installing parking- brake cables removing or’installing head assemblies inspecting gasoline fuel system

Rail vehicle dynamic response to a nonlinear physical 'in-service' model of its secondary suspension hydraulic dampers

NASA Astrophysics Data System (ADS)

Wang, W. L.; Zhou, Z. R.; Yu, D. S.; Qin, Q. H.; Iwnicki, S.

2017-10-01

A full nonlinear physical 'in-service' model was built for a rail vehicle secondary suspension hydraulic damper with shim-pack-type valves. In the modelling process, a shim pack deflection theory with an equivalent-pressure correction factor was proposed, and a Finite Element Analysis (FEA) approach was applied. Bench test results validated the damper model over its full velocity range and thus also proved that the proposed shim pack deflection theory and the FEA-based parameter identification approach are effective. The validated full damper model was subsequently incorporated into a detailed vehicle dynamics simulation to study how its key in-service parameter variations influence the secondary-suspension-related vehicle system dynamics. The obtained nonlinear physical in-service damper model and the vehicle dynamic response characteristics in this study could be used in the product design optimization and nonlinear optimal specifications of high-speed rail hydraulic dampers.

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

NASA Astrophysics Data System (ADS)

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.

Some cable suspension systems and their effects on the flexural frequencies of slender aerospace structures

NASA Technical Reports Server (NTRS)

Herr, R. W.

1974-01-01

The effects of several cable suspension configurations on the first free-free flexural frequency of uniform beams have been determined by experiment and analysis. The results of this study confirm that in general the larger the test vehicle the larger is the flexural frequency measurement error attributable to a given cable suspension configuration. For horizontally oriented beams representing modern aerospace vehicles of average size and flexibility, the restraining effects of all but the shortest support cables were minor. The restraining effects of support cables of moderate length attached near the base of vertically oriented vehicles were overshadowed by the effects of beam compression due to gravity.

Analysis of Dynamic Stiffness Effect of Primary Suspension Helical Springs on Railway Vehicle Vibration

NASA Astrophysics Data System (ADS)

Sun, W.; Thompson, D. J.; Zhou, J.; Gong, D.

2016-09-01

Helical springs within the primary suspension are critical components for isolating the whole vehicle system from vibration generated at the wheel/rail contact. As train speeds increase, the frequency region of excitation becomes larger, and a simplified static stiffness can no longer represent the real stiffness property in a vehicle dynamic model. Coil springs in particular exhibit strong internal resonances, which lead to high vibration amplitudes within the spring itself as well as degradation of the vibration isolation. In this paper, the dynamic stiffness matrix method is used to determine the dynamic stiffness of a helical spring from a vehicle primary suspension. Results are confirmed with a finite element analysis. Then the spring dynamic stiffness is included within a vehicle-track coupled dynamic model of a high speed train and the effect of the dynamic stiffening of the spring on the vehicle vibration is investigated. It is shown that, for frequencies above about 50 Hz, the dynamic stiffness of the helical spring changes sharply. Due to this effect, the vibration transmissibility increases considerably which results in poor vibration isolation of the primary suspension. Introducing a rubber layer in series with the coil spring can attenuate this effect.

The pitch-heave dynamics of transportation vehicles

NASA Technical Reports Server (NTRS)

Sweet, L. M.; Richardson, H. H.

1975-01-01

The analysis and design of suspensions for vehicles of finite length using pitch-heave models is presented. Dynamic models for the finite length vehicle include the spatial distribution of the guideway input disturbance over the vehicle length, as well as both pitch and heave degrees-of-freedom. Analytical results relate the vehicle front and rear accelerations to the pitch and heave natural frequencies, which are functions of vehicle suspension geometry and mass distribution. The effects of vehicle asymmetry and suspension contact area are evaluated. Design guidelines are presented for the modification of vehicle and suspension parameters to meet alternative ride quality criteria.

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

NASA Astrophysics Data System (ADS)

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.

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

NASA Astrophysics Data System (ADS)

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.

Articulated Suspension Without Springs

NASA Technical Reports Server (NTRS)

Bickler, Donald B.

1990-01-01

Wheels negotiate bumps and holes with minimal tilting of vehicle body. In new suspension, wheel climbs obstacle as high as 1 1/2 times its diameter without excessive tilting of chassis. Provides highly stable ride over rough ground for such vehicles as wheelchairs, military scout cars, and police and fire robots. System of levers distributes weight to wheels. Sized to distribute equal or other desired portions of load among wheels.

Dynamic analysis of the American Maglev system. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seda-Sanabria, Y.; Ray, J.C.

1996-06-01

Understanding the dynamic interaction between a magnetic levitated (Maglev) vehicle and its supporting guideway is essential in the evaluation of the performance of such a system. This interacting coupling, known as vehicle/guideway interaction (VGI), has a significant effect on system parameters such as the required magnetic suspension forces and gaps, vehicular ride quality, and guideway deflections and stresses. This report presents the VGI analyses conducted on an actual Maglev system concept definition (SCD), the American Maglev SCD, using a linear-elastic finite-element (FE) model. Particular interest was focused on the comparison of the ride quality of the vehicle, using two differentmore » suspension systems, and their effect on the guideway structure. The procedure and necessary assumptions in the modeling are discussed.« less

Dynamic interaction between vehicles and infrastructure experiment (DIVINE) : policy implications

DOT National Transportation Integrated Search

1998-01-01

The Dynamic Interaction between Vehicles and Infrastructure Experiment (DIVINE) Project provided scientific evidence of the dynamic effects of heavy vehicles and their suspension systems on pavements and bridges. These conclusions are detailed in the...

Dynamic interaction between vehicles and infrastructure experiment (DIVINE) : technical report

DOT National Transportation Integrated Search

1998-10-27

The Dynamic Interaction between Vehicles and Infrastructure Experiment (DIVINE) Project provides scientific evidence of the dynamic effects of heavy vehicles and their suspension systems on pavements and bridges in support of transport policy decisio...

The Effects of Parachute System Mass and Suspension-Line Elastic Properties on the LADT #3 Viking Parachute Inflation Load

NASA Technical Reports Server (NTRS)

Talay, Theodore A.; Poole, Lamont R.

1971-01-01

Analytical calculations have considered the effects of 1) varying parachute system mass, 2) suspension-line damping, and 3) alternate suspension-line force-elongation data on the canopy force history. Results indicate the canopy force on the LADT #3 parachute did not substantially exceed the recorded vehicle force reading and that the above factors can have significant effects on the canopy force history. Analytical calculations have considered the effects of i) varying parachute system mass, 2) suspension line damping, and 3) different suspension-line force-elongation data on the canopy force history. Based on the results of this study the following conclusions are drawn: Specifically, 1. At the LADT #3 failure time of 1.70 seconds, the canopy force ranged anywhere from 15.7% below to 2.4% above the vehicle force depending upon the model and data used. Therefore, the canopy force did not substantially exceed the recorded vehicle force reading. 2. At a predicted full inflation time of 1.80 seconds the canopy force would be greater than the vehicle force by from 1.1% to 10.6%, again depending upon the model and data used. Generally, 3. At low altitudes, enclosed and apparent air mass can significantly effect the canopy force calculated and should, therefore, not be neglected. 4. The canopy force calculations are sensitive to decelerator physical properties. In this case changes in the damping and/or force-elongation characteristics produced significant changes in the canopy force histories. Accurate prediction of canopy force histories requires accurate inputs in these areas.

A hybrid electromagnetic shock absorber for active vehicle suspension systems

NASA Astrophysics Data System (ADS)

Ebrahimi, Babak; Bolandhemmat, Hamidreza; Behrad Khamesee, Mir; Golnaraghi, Farid

2011-02-01

The use of electromagnetic dampers (ED) in vehicle active suspension systems has drawn considerable attention in the past few years, attributed to the fact that active suspension systems have shown superior performance in improving ride comfort and road handling of terrain vehicles, compared with their passive and semi-active counterparts. Although demonstrating superb performance, active suspensions still have some shortcomings that must be overcome. They have high energy consumption, weight, and cost and are not fail-safe in case of a power breakdown. The novel hybrid ED, which is proposed in this paper, is a potential solution to the above-mentioned drawbacks of conventional active suspension systems. The proposed hybrid ED is designed to inherit the high-performance characteristics of an active ED with the reliability of a passive damper in a single package. The eddy current damping effect is utilised as a source of the passive damping. First, a prototype ED is designed and fabricated. The prototype ED is then utilised to experimentally establish the design requirements for a real-size active ED. This is accomplished by comparing its vibration isolation performance in a 1-DOF quarter-car test rig with that of a same-class semi-active damper. Then, after a real-size active ED is designed, the concept of hybrid damper is introduced to the damper design to address the drawbacks of the active ED. Finally, the finite-element method is used to accurately model and analyse the designed hybrid damper. It is demonstrated that by introducing the eddy current damping effect to the active part, a passive damping of approximately 1570 Ns/m is achieved. This amount of passive damping guarantees that the damper is fail-safe and reduces the power consumption more than 70%, compared with an active ED in an automotive active suspension system.

Robust H∞ control of active vehicle suspension under non-stationary running

NASA Astrophysics Data System (ADS)

Guo, Li-Xin; Zhang, Li-Ping

2012-12-01

Due to complexity of the controlled objects, the selection of control strategies and algorithms in vehicle control system designs is an important task. Moreover, the control problem of automobile active suspensions has been become one of the important relevant investigations due to the constrained peculiarity and parameter uncertainty of mathematical models. In this study, after establishing the non-stationary road surface excitation model, a study on the active suspension control for non-stationary running condition was conducted using robust H∞ control and linear matrix inequality optimization. The dynamic equation of a two-degree-of-freedom quarter car model with parameter uncertainty was derived. The H∞ state feedback control strategy with time-domain hard constraints was proposed, and then was used to design the active suspension control system of the quarter car model. Time-domain analysis and parameter robustness analysis were carried out to evaluate the proposed controller stability. Simulation results show that the proposed control strategy has high systemic stability on the condition of non-stationary running and parameter uncertainty (including suspension mass, suspension stiffness and tire stiffness). The proposed control strategy can achieve a promising improvement on ride comfort and satisfy the requirements of dynamic suspension deflection, dynamic tire loads and required control forces within given constraints, as well as non-stationary running condition.

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

NASA Astrophysics Data System (ADS)

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%.

Suspension Parameter Measurements of Wheeled Military Vehicles

DTIC Science & Technology

2012-08-01

suspension through the wheel pads. The SPIdER was designed so that in the future, with a modest amount of modification , it can be upgraded to include the...AND MOBILITY (P&M) MINI-SYMPOSIUM AUGUST 14-16, MICHIGAN SUSPENSION PARAMETER MEASUREMENTS OF WHEELED MILITARY VEHICLES Dale Andreatta Gary...was built to measure the suspension parameters of any military wheeled vehicle. This is part of an ongoing effort to model and predict vehicle

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

NASA Astrophysics Data System (ADS)

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.

49 CFR 38.73 - Doorways.

Code of Federal Regulations, 2010 CFR

2010-10-01

.... Vertical alignment may be accomplished by vehicle air suspension, automatic ramps or lifts, or any... SPECIFICATIONS FOR TRANSPORTATION VEHICLES Light Rail Vehicles and Systems § 38.73 Doorways. (a) Clear width—(1) All passenger doorways on vehicle sides shall have minimum clear openings of 32 inches when open. (2...

Summary of Optimization Techniques That Can Be Applied to Suspension System Design

DOT National Transportation Integrated Search

1973-03-01

Summaries are presented of the analytic techniques available for three levitated vehicle suspension optimization problems: optimization of passive elements for fixed configuration; optimization of a free passive configuration; optimization of a free ...

Vehicle load-equalization system

NASA Technical Reports Server (NTRS)

Creasy, W. K.

1976-01-01

System uses cables and associated pulleys to form closed-loop suspension system for terrain compensation. Loop causes reactions at each of three wheels in response to loading at remaining wheel. Simplicity of design should be of interest to designers and manufacturers of construction equipment and off-road vehicles.

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.

PubMed

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.

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

NASA Astrophysics Data System (ADS)

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.

Modelling and validation of electromechanical shock absorbers

NASA Astrophysics Data System (ADS)

Tonoli, Andrea; Amati, Nicola; Girardello Detoni, Joaquim; Galluzzi, Renato; Gasparin, Enrico

2013-08-01

Electromechanical vehicle suspension systems represent a promising substitute to conventional hydraulic solutions. However, the design of electromechanical devices that are able to supply high damping forces without exceeding geometric dimension and mass constraints is a difficult task. All these challenges meet in off-road vehicle suspension systems, where the power density of the dampers is a crucial parameter. In this context, the present paper outlines a particular shock absorber configuration where a suitable electric machine and a transmission mechanism are utilised to meet off-road vehicle requirements. A dynamic model is used to represent the device. Subsequently, experimental tests are performed on an actual prototype to verify the functionality of the damper and validate the proposed model.

49 CFR 38.53 - Doorways.

Code of Federal Regulations, 2010 CFR

2010-10-01

... accomplished by vehicle air suspension or other suitable means of meeting the requirement. (2) Exception. New... SPECIFICATIONS FOR TRANSPORTATION VEHICLES Rapid Rail Vehicles and Systems § 38.53 Doorways. (a) Clear width. (1) Passenger doorways on vehicle sides shall have clear openings at least 32 inches wide when open. (2) If...

Dynamics, stability, and control of maglev systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cai, Y.; Chen, S.S.; Rote, D.M.

1993-06-01

The dynamic response of maglev systems is important in several respects: Safety and ride quality, guideway design, and system costs. The dynamic response of vehicles is the key element in the determination of ride quality, and vehicle stability is one of the important elements relative to safety. To design a proper guideway that provides acceptable ride quality in the stable region, the vehicle dynamics must be understood. The trade-off between guideway smoothness and the levitation and control systems must be considered if maglev systems are to be economically feasible. This paper is a summary of our previous work on dynamics,more » stability and control of maglev systems. First of all, the importance of dynamics of vehicle/guideway of maglev systems is discussed. Emphasis is placed on the modeling vehicle/guideway interactions of maglev systems with a multicar, or multiload vehicle traversing on a single or double-span flexible guideway. Coupled effects of vehicle/guideway interactions in wide range of vehicle speeds with various vehicle and guideway parameters for maglev systems are investigated. Secondly, the alternative control designs of maglev vehicle suspension systems are investigated in this study to achieve safe, stable operation and acceptable ride comfort requires some form of vehicle motion control. Active and semi-active control law designs are introduced into primary and secondary suspensions of maglev vehicles. Finally, this paper discusses the stability of maglev systems based on experimental data, scoping calculations, and simple mathematical models. Divergence and flutter are obtained for coupled vibration of a three-degree-of-freedom maglev vehicle on a guideway consisting of double L-shaped aluminum segments. The theory and analysis developed in this study provides basic stability characteristics and identifies future research needs for maglev systems.« less

Dynamics, stability, and control of maglev systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cai, Y.; Chen, S.S.; Rote, D.M.

1993-01-01

The dynamic response of maglev systems is important in several respects: Safety and ride quality, guideway design, and system costs. The dynamic response of vehicles is the key element in the determination of ride quality, and vehicle stability is one of the important elements relative to safety. To design a proper guideway that provides acceptable ride quality in the stable region, the vehicle dynamics must be understood. The trade-off between guideway smoothness and the levitation and control systems must be considered if maglev systems are to be economically feasible. This paper is a summary of our previous work on dynamics,more » stability and control of maglev systems. First of all, the importance of dynamics of vehicle/guideway of maglev systems is discussed. Emphasis is placed on the modeling vehicle/guideway interactions of maglev systems with a multicar, or multiload vehicle traversing on a single or double-span flexible guideway. Coupled effects of vehicle/guideway interactions in wide range of vehicle speeds with various vehicle and guideway parameters for maglev systems are investigated. Secondly, the alternative control designs of maglev vehicle suspension systems are investigated in this study to achieve safe, stable operation and acceptable ride comfort requires some form of vehicle motion control. Active and semi-active control law designs are introduced into primary and secondary suspensions of maglev vehicles. Finally, this paper discusses the stability of maglev systems based on experimental data, scoping calculations, and simple mathematical models. Divergence and flutter are obtained for coupled vibration of a three-degree-of-freedom maglev vehicle on a guideway consisting of double L-shaped aluminum segments. The theory and analysis developed in this study provides basic stability characteristics and identifies future research needs for maglev systems.« less

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

NASA Astrophysics Data System (ADS)

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.

Dynamic stability of repulsive-force maglev suspension systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cai, Y.; Rote, D.M.; Mulcahy, T.M.

1996-11-01

This report summarizes the research performed on maglev vehicle dynamic stability at Argonne National Laboratory during the past few years. It also documents both measured and calculated magnetic-force data. Because dynamic instability is not acceptable for any commercial maglev system, it is important to consider this phenomenon in the development of all maglev systems. This report presents dynamic stability experiments on maglev systems and compares the results with predictions calculated by a nonlinear-dynamics computer code. Instabilities of an electrodynamic-suspension system type vehicle model were obtained by experimental observation and computer simulation of a five-degree-of-freedom maglev vehicle moving on a guidewaymore » that consists of a pair of L-shaped aluminum conductors attached to a rotating wheel. The experimental and theoretical analyses developed in this study identify basic stability characteristics and future research needs of maglev systems.« less

A review of dynamic stability of repulsive-force maglev suspension systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cai, Y.; Rote, D.M.

1998-07-01

Vehicle dynamics and the need to satisfy ride quality requirements have long been recognized as crucial to the commercial success of passenger-carrying transportation systems. Design concepts for maglev systems are no exception. Early maglev investigators and designers were well aware of the importance of ride quality and took care to ensure that their designs would meet acceptable ride quality standards. In contrast, the dynamic stability of electrodynamic suspension (EDS) systems, which has obvious implications for system safety and cost as well as for ride quality, has not received nearly as much attention. Because of the well-known under-damped nature of EDSmore » suspension systems and the observation of instabilities in laboratory-scale model systems, it is prudent to develop a better understanding of vehicle stability characteristics. The work reported in this was undertaken with the intention of summarizing information that has been accumulated worldwide and that is relevant to dynamic stability of repulsive-force maglev suspension systems, assimilating that information, and gaining an understanding of the factors that influence that stability. Included in the paper is a discussion and comparison of results acquired from some representative tests of large-scale vehicles on linear test tracks, together with analytical and laboratory-scale investigations of stability and dynamics of EDS systems. This paper will also summarize the R and D activities at Argonne National Laboratory (ANL) since 1991 to study the nature of the forces that are operative in an EDS system and the dynamic stability of such systems.« less

49 CFR 567.3 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., suspension system, and braking system, in the state that those systems are to be part of the completed... authority. Addendum means the document described in § 568.5 of this chapter. Altered vehicle means a completed vehicle previously certified in accordance with § 567.4 or § 567.5 that has been altered other...

Novel mechatronic solutions incorporating inerters for railway vehicle vertical secondary suspensions

NASA Astrophysics Data System (ADS)

Matamoros-Sanchez, Alejandra Z.; Goodall, Roger M.

2015-02-01

This paper discusses the effects of inerter-based passive networks in the design of novel mechatronic solutions for improving the vertical performance of a bogied railway vehicle. Combinations of inerter-based structures and active suspensions comprise distinct novel mechatronic solutions for the vertical secondary suspension of the vehicle. The parameters of the active and passive parts of the overall configuration are optimised so that a synergy arises to enhance the vehicle vertical performance and simplify common mechatronic suspension design conflicts. The study is performed by combining inerter-based suspensions with well-established active control (output-based and model-based) strategies for ride quality enhancement. Also, a novel nonlinear control strategy, here called 'Adaptive Stiffness', is incorporated for suspension deflection regulation to complement the well-known local implementation of skyhook damping. This would complete a significant set of control strategies to produce general conclusions. The vehicle performance is assessed through the vertical accelerations of the vehicle body as an initial investigation. Attained results show the potential of the inerter concept for innovating mechatronic technologies to achieve substantial improvements in railway vehicle vertical ride quality with reduced actuator force.

Fuzzy chaos control for vehicle lateral dynamics based on active suspension system

NASA Astrophysics Data System (ADS)

Huang, Chen; Chen, Long; Jiang, Haobin; Yuan, Chaochun; Xia, Tian

2014-07-01

The existing research of the active suspension system (ASS) mainly focuses on the different evaluation indexes and control strategies. Among the different components, the nonlinear characteristics of practical systems and control are usually not considered for vehicle lateral dynamics. But the vehicle model has some shortages on tyre model with side-slip angle, road adhesion coefficient, vertical load and velocity. In this paper, the nonlinear dynamic model of lateral system is considered and also the adaptive neural network of tire is introduced. By nonlinear analysis methods, such as the bifurcation diagram and Lyapunov exponent, it has shown that the lateral dynamics exhibits complicated motions with the forward speed. Then, a fuzzy control method is applied to the lateral system aiming to convert chaos into periodic motion using the linear-state feedback of an available lateral force with changing tire load. Finally, the rapid control prototyping is built to conduct the real vehicle test. By comparison of time response diagram, phase portraits and Lyapunov exponents at different work conditions, the results on step input and S-shaped road indicate that the slip angle and yaw velocity of lateral dynamics enter into stable domain and the results of test are consistent to the simulation and verified the correctness of simulation. And the Lyapunov exponents of the closed-loop system are becoming from positive to negative. This research proposes a fuzzy control method which has sufficient suppress chaotic motions as an effective active suspension system.

Effect of suspension kinematic on 14 DOF vehicle model

NASA Astrophysics Data System (ADS)

Wongpattananukul, T.; Chantharasenawong, C.

2017-12-01

Computer simulations play a major role in shaping modern science and engineering. They reduce time and resource consumption in new studies and designs. Vehicle simulations have been studied extensively to achieve a vehicle model used in minimum lap time solution. Simulation result accuracy depends on the abilities of these models to represent real phenomenon. Vehicles models with 7 degrees of freedom (DOF), 10 DOF and 14 DOF are normally used in optimal control to solve for minimum lap time. However, suspension kinematics are always neglected on these models. Suspension kinematics are defined as wheel movements with respect to the vehicle body. Tire forces are expressed as a function of wheel slip and wheel position. Therefore, the suspension kinematic relation is appended to the 14 DOF vehicle model to investigate its effects on the accuracy of simulate trajectory. Classical 14 DOF vehicle model is chosen as baseline model. Experiment data is collected from formula student style car test runs as baseline data for simulation and comparison between baseline model and model with suspension kinematic. Results show that in a single long turn there is an accumulated trajectory error in baseline model compared to model with suspension kinematic. While in short alternate turns, the trajectory error is much smaller. These results show that suspension kinematic had an effect on the trajectory simulation of vehicle. Which optimal control that use baseline model will result in inaccuracy control scheme.

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

NASA Astrophysics Data System (ADS)

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.

Contributions to modeling functionality of a high frequency damper system

NASA Astrophysics Data System (ADS)

Sirbu, E. A.; Horga, S.; Vrabioiu, G.

2016-08-01

Due to the necessity of improving the handling performances of a motor vehicle, it is imperative to understand the suspensions properties that affects ride and directional respons.The construction of a fero-magnetic shock absorber is based on two bellows interconnected by a pipe-line. Through this pipe-line the fero-magnetic fluid is carried between the two bellows. The damping characteristic of the shock absorber is affected by the viscosity of the fero-magnetic fluid. The viscosity of the fluid, is controlled through a electric coil mounted on the bellows connecting pipe-line. Modifying the electrical field of the coil, the viscosity of the fluid will change, finally affecting the damping characteristic of the shock absorber. A recent system called „CCD Pothole Suspension” is implemented on Ford vehicles. By modifying the dampning characteristic of the shock absorbers, vehicle daynamics can be improved; also the risk of damaging the suspension will be decreased. The approach of this paper is to analyze the behaviour of the fero magnetic damper, thus determining how it will affect the performances of the vehicle suspensions. The experimental research will provide a better understanding of the behavior of the fero-magnetic shock absorber, and the possible advantages of using this system.

New level of vehicle comfort and vehicle stability via utilisation of the suspensions anti-dive and anti-squat geometry

NASA Astrophysics Data System (ADS)

Lindvai-Soos, Daniel; Horn, Martin

2018-07-01

In this article a novel vehicle dynamics control concept is designed for a vehicle equipped with wheel individual electric traction machines, electronically controlled brakes and semi-active suspensions. The suspension's cross-couplings between traction forces and vertical forces via anti-dive and anti-squat geometry is utilised in the control concept to improve driving comfort and driving stability. The control concept is divided into one main and two cascaded branches. The main controller consists of a multivariable vehicle dynamics controller and a control allocation scheme to improve the vehicle's driving comfort. The cascaded feedback loops maintain the vehicle's stability according to wheel slip and vehicle sideslip. The performance of the combined vehicle dynamics controller is compared to a standard approach in simulation. It can be stated that the controller piloting semi-active suspensions together with brake and traction devices enables a superior performance regarding comfort and stability.

Road simulation for four-wheel vehicle whole input power spectral density

NASA Astrophysics Data System (ADS)

Wang, Jiangbo; Qiang, Baomin

2017-05-01

As the vibration of running vehicle mainly comes from road and influence vehicle ride performance. So the road roughness power spectral density simulation has great significance to analyze automobile suspension vibration system parameters and evaluate ride comfort. Firstly, this paper based on the mathematical model of road roughness power spectral density, established the integral white noise road random method. Then in the MATLAB/Simulink environment, according to the research method of automobile suspension frame from simple two degree of freedom single-wheel vehicle model to complex multiple degrees of freedom vehicle model, this paper built the simple single incentive input simulation model. Finally the spectrum matrix was used to build whole vehicle incentive input simulation model. This simulation method based on reliable and accurate mathematical theory and can be applied to the random road simulation of any specified spectral which provides pavement incentive model and foundation to vehicle ride performance research and vibration simulation.

Non-dimensionalised closed-form parametric analysis of semi-active vehicle suspensions using a quarter-car model

NASA Astrophysics Data System (ADS)

Ahmadian, Mehdi; Blanchard, Emmanuel

2011-02-01

This article provides a non-dimensionalised closed-form analysis of semi-active vehicle suspensions, using a quarter-car model. The derivation of the closed-form solutions for three indices that can be used for ride comfort, vehicle handling, and stability are presented based on non-dimensionalised suspension parameters. The behaviour of semi-active vehicle suspensions is evaluated using skyhook, groundhook, and hybrid control policies, and compared with passive suspensions. The relationship between vibration isolation, suspension deflection, and road holding is studied, using three performance indices based on the mean square of the sprung mass acceleration, rattle space, and tyre deflection, respectively. The results of the study indicate that the hybrid control policy yields significantly better comfort than a passive suspension, without reducing the road-holding quality or increasing the suspension displacement for typical passenger cars. The results also indicate that for typical passenger cars, the hybrid control policy results in a better compromise between comfort, road holding and suspension travel requirements than both the skyhook and groundhook control methods.

Effects of the Truck Suspension System on Animal Welfare, Carcass and Meat Quality Traits in Pigs

PubMed Central

Dalla Costa, Filipe Antônio; Lopes, Letícia S.; Dalla Costa, Osmar Antônio

2017-01-01

Simple Summary Transportation is a complex stressor in which animals are exposed to a series negatively stimuli, such as vibration, new environmental conditions, variation in temperature and humidity, social mixing, noises among other poor factors, which can result in welfare problems and economic losses such as increased skin lesions, poorer pork quality traits. Transport stress may be reduced through a vehicle suspension system that provides a much smoother ride during transport, and consequently is less aversive to pigs. However, air suspension systems are more expensive and have bigger maintenance costs. This increase in transportation cost must be supported by the benefits from improvements in quality of freight transport; otherwise, the truckers will be paying unnecessarily for a similar or equivalent ride quality. Thus, finishing pigs were assessed after transport to slaughter by the same two double-decked trucks using two types of commercial vehicle suspension, leaf-spring and air suspension, to compare effects on blood cortisol and lactate at exsanguination, behaviour during lairage, and carcass (skin lesions) and pork quality traits. The use of leaf-spring suspension system negatively affects the welfare of pigs due to the increased carcass damage and resulted in poorer pork quality traits. Abstract The objective of this study was to assess the effects of two types of commercial suspension (leaf-spring (LS) vs. air suspension (AS)) installed on two similar double-decked trucks on blood cortisol and lactate concentration, lairage behavior, carcass skin lesions and pork quality traits of 120 crossbred pigs. The suspension type neither influenced pig behaviour in lairage nor blood cortisol and lactate concentrations (p > 0.10). However, when compared with the AS suspension system, the use of LS increased the number of skin lesions in the back and thigh (p = 0.03 and p = 0.01, respectively) and produced thigh with lower pHu (p < 0.001) and yellower colour (higher b* value; p = 0.03), and paler back muscles (subjective colour; p < 0.05), with a tendency to lower pH (p = 0.06). Therefore, the use air suspension system can improve carcass and meat quality traits of pigs transported to slaughter. PMID:28106802

A comparative analysis of passive twin tube and skyhook MRF dampers for motorcycle front suspensions

NASA Astrophysics Data System (ADS)

Ahmadian, Mehdi; Gravatt, John

2004-07-01

A comparative analysis between conventional passive twin tube dampers and skyhook-controlled magneto-rheological fluid (MRF) dampers for motorcycle front suspensions is provided, based on single axis testing in a damper test rig and suspension performance testing in road trials. Performance motorcycles, while boasting extremely light suspension components and competition-ready performance, have an inherent weakness in comfort, as the suspension systems are designed primarily for racing purposes. Front suspension acceleration and shock loading transmit directly through the front suspension triple clamp into the rider's arms and shoulders, causing rapid fatigue in shoulder muscles. Magneto-rheological fluid dampers and skyhook control systems offer an alternative to conventional sport motorcycle suspensions - both performance and comfort can be combined in the same package. Prototype MRF dampers designed and manufactured specifically for this application require no more space than conventional twin tube designs while adding only 1.7 pounds total weight to the system. The MRF dampers were designed for high controllability and low power consumption, two vital considerations for a motorcycle application. The tests conducted include the dampers' force-velocity curve testing in a damper test rig and suspension performance based on damper position, velocity, and acceleration measurement. Damper test rig results show the MRF dampers have a far greater range of adjustability than the test vehicle's OEM dampers. Combined with a modified sky-hook control system, the MRF dampers can greatly decrease the acceleration and shock loading transmitted to the rider through the handlebars while contributing performance in manners such as anti-dive under braking. Triple clamp acceleration measurements from a variety of staged road conditions, such as sinusoidal wave inputs, will be compared to subjective test-rider field reports to establish a correlation between rider fatigue and the front suspension performance. This testing will be conducted on the OEM vehicle suspension, the passive MRF dampers, and the skyhook-controlled MRF damper front suspension. The results of this test will determine the viability of skyhook-controlled MRF damper systems on motorcycles for performance gain and fatigue reduction.

Identification of vehicle suspension parameters by design optimization

NASA Astrophysics Data System (ADS)

Tey, J. Y.; Ramli, R.; Kheng, C. W.; Chong, S. Y.; Abidin, M. A. Z.

2014-05-01

The design of a vehicle suspension system through simulation requires accurate representation of the design parameters. These parameters are usually difficult to measure or sometimes unavailable. This article proposes an efficient approach to identify the unknown parameters through optimization based on experimental results, where the covariance matrix adaptation-evolutionary strategy (CMA-es) is utilized to improve the simulation and experimental results against the kinematic and compliance tests. This speeds up the design and development cycle by recovering all the unknown data with respect to a set of kinematic measurements through a single optimization process. A case study employing a McPherson strut suspension system is modelled in a multi-body dynamic system. Three kinematic and compliance tests are examined, namely, vertical parallel wheel travel, opposite wheel travel and single wheel travel. The problem is formulated as a multi-objective optimization problem with 40 objectives and 49 design parameters. A hierarchical clustering method based on global sensitivity analysis is used to reduce the number of objectives to 30 by grouping correlated objectives together. Then, a dynamic summation of rank value is used as pseudo-objective functions to reformulate the multi-objective optimization to a single-objective optimization problem. The optimized results show a significant improvement in the correlation between the simulated model and the experimental model. Once accurate representation of the vehicle suspension model is achieved, further analysis, such as ride and handling performances, can be implemented for further optimization.

Magnetic suspension and pointing system

NASA Technical Reports Server (NTRS)

Anderson, W. W.; Groom, N. J. (Inventor)

1978-01-01

An apparatus is reported for accurate pointing of instruments on a carrier vehicle and for isolation of the instruments from the vehicle's motion disturbances. The apparatus includes two assemblies with connecting interfaces. The first assembly is attached to the carrier vehicle and consists of an azimuth gimbal and an elevation gimbal which provide coarse pointing by allowing two rotations of the instruments relative to the carrier vehicle. The second or vernier pointing assembly is made up of magnetic suspension and fine pointing actuators, roll motor segments, and an instrument mounting plase which provides appropriate magnetic circuits for the actuators and the roll motor segments. The vernier pointing assembly provides attitude fine pointing and roll positioning of the instruments as well as six degree-of-freedom isolation from carrier motion disturbances.

Annoyance rate evaluation method on ride comfort of vehicle suspension system

NASA Astrophysics Data System (ADS)

Tang, Chuanyin; Zhang, Yimin; Zhao, Guangyao; Ma, Yan

2014-03-01

The existing researches of the evaluation method of ride comfort of vehicle mainly focus on the level of human feelings to vibration. The level of human feelings to vibration is influenced by many factors, however, the ride comfort according to the common principle of probability and statistics and simple binary logic is unable to reflect these uncertainties. The random fuzzy evaluation model from people subjective response to vibration is adopted in the paper, these uncertainties are analyzed from the angle of psychological physics. Discussing the traditional evaluation of ride comfort during vehicle vibration, a fuzzily random evaluation model on the basis of annoyance rate is proposed for the human body's subjective response to vibration, with relevant fuzzy membership function and probability distribution given. A half-car four degrees of freedom suspension vibration model is described, subject to irregular excitations from the road surface, with the aid of software Matlab/Simulink. A new kind of evaluation method for ride comfort of vehicles is proposed in the paper, i.e., the annoyance rate evaluation method. The genetic algorithm and neural network control theory are used to control the system. Simulation results are obtained, such as the comparison of comfort reaction to vibration environments between before and after control, relationship of annoyance rate to vibration frequency and weighted acceleration, based on ISO 2631/1(1982), ISO 2631-1(1997) and annoyance rate evaluation method, respectively. Simulated assessment results indicate that the proposed active suspension systems prove to be effective in the vibration isolation of the suspension system, and the subjective response of human being can be promoted from very uncomfortable to a little uncomfortable. Furthermore, the novel evaluation method based on annoyance rate can further estimate quantitatively the number of passengers who feel discomfort due to vibration. A new analysis method of vehicle comfort is presented.

Dynamic Performance of Subway Vehicle with Linear Induction Motor System

NASA Astrophysics Data System (ADS)

Wu, Pingbo; Luo, Ren; Hu, Yan; Zeng, Jing

The light rail vehicle with Linear Induction Motor (LIM) bogie, which is a new type of urban rail traffic tool, has the advantages of low costs, wide applicability, low noise, simple maintenance and better dynamic behavior. This kind of vehicle, supported and guided by the wheel and rail, is not driven by the wheel/rail adhesion force, but driven by the electromagnetic force between LIM and reaction plate. In this paper, three different types of suspensions and their characteristic are discussed with considering the interactions both between wheel and rail and between LIM and reaction plate. A nonlinear mathematical model of the vehicle with LIM bogie is set up by using the software SIMPACK, and the electromechanical model is also set up on Simulink roof. Then the running behavior of the LIM vehicle is simulated, and the influence of suspension on the vehicle dynamic performance is investigated.

Altitude valve for railway suspension control system

NASA Astrophysics Data System (ADS)

Zhang, Xuan; Zhang, Lihao; Li, Qingxuan; Chen, WanSong

2017-09-01

With the variation of people and material during vehicle service, the gravity of vehicle could be unbalanced. As a result it might cause accident. In order to solve this problem, altitude valve is assembled on board. It can adjust the gravity of vehicle by the intake and outlet progress of the spring in the altitude valve to prevent the tilt of vehicles.

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

NASA Astrophysics Data System (ADS)

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.

Comparison of Rheological and Sedimentation Behavior of Commercially Available Suspending Vehicles for Oral Pharmaceutical Preparations.

PubMed

Visser, J Carolina; Ten Seldam, Inge E J; van der Linden, Isabella J; Hinrichs, Wouter L J; Veenendaal, Reinier F H; Dijkers, Eli C F; Woerdenbag, Herman J

2018-01-01

A pharmaceutical suspension is a semi-liquid dosage form suitable for patients being unable to swallow solid medicines such as tablets and capsules. A vehicle used for the preparation of pharmaceutical oral suspensions preferably shows pseudo-plastic behavior. In a product that gets thinner with agitation and thicker upon standing, slow settlement of the suspended active pharmaceutical ingredient is combined with good pourability and rehomogenization. This gives the best guarantee of uniformity of dose for oral suspensions. In this study, the rheological behavior of commercially available ready-to-use vehicles for oral pharmaceutical preparations was compared, and the sedimentation of paracetamol dispersed in these vehicles was investigated. With SuspendIt and SyrSpend SF PH4 (Liquid), both pseudoplastic vehicles, very stable paracetamol suspensions were obtained. Of these two vehicles, SyrSpend SF PH4 (Liquid) displayed somewhat higher viscosity, which is a favorable quality characteristic for suspensions. Copyright© by International Journal of Pharmaceutical Compounding, Inc.

49 CFR 565.12 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... structure, power train, steering system, suspension system and braking system, to the extent that those.... (m) Model year means the year used to designate a discrete vehicle model, irrespective of the...

49 CFR 565.12 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... structure, power train, steering system, suspension system and braking system, to the extent that those.... (m) Model year means the year used to designate a discrete vehicle model, irrespective of the...

49 CFR 565.12 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... structure, power train, steering system, suspension system and braking system, to the extent that those.... (m) Model year means the year used to designate a discrete vehicle model, irrespective of the...

49 CFR 565.12 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... structure, power train, steering system, suspension system and braking system, to the extent that those.... (m) Model year means the year used to designate a discrete vehicle model, irrespective of the...

Magnetic suspension and pointing system. [on a carrier vehicle

NASA Technical Reports Server (NTRS)

Anderson, W. W.; Groom, N. J. (Inventor)

1979-01-01

Apparatus for providing accurate pointing of instruments on a carrier vehicle and for providing isolation of the instruments from the vehicle's motion disturbances is presented. The apparatus includes two assemblies, with connecting interfaces, each assembly having a separate function. The first assembly is attached to the carrier vehicle and consists of an azimuth gimbal and an elevation gimbal which provide coarse pointing of the instruments by allowing two rotations of the instruments relative to the carrier vehicle. The second or vernier pointing assembly is made up of magnetic suspension and fine pointing actuators, roll motor segments, and an instrument mounting plate around which a continuous annular rim is attached which provides appropriate magnetic circuits for the actuators and the roll motor segments. The vernier pointing assembly provides six degree-of-freedom isolation from carrier motion disturbances.

49 CFR 592.7 - Suspension, revocation, and reinstatement of suspended registrations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... vehicle during the time that its registration has been suspended. (d) Effect of suspension or revocation... date of the suspension or revocation all vehicles that it imported to which it has not affixed a... 49 Transportation 7 2010-10-01 2010-10-01 false Suspension, revocation, and reinstatement of...

An analytical design approach for self-powered active lateral secondary suspensions for railway vehicles

NASA Astrophysics Data System (ADS)

Wang, Peng; Li, Hong; Zhang, Jiye; Mei, TX

2015-10-01

In this paper, an analytical design approach for the development of self-powered active suspensions is investigated and is applied to optimise the control system design for an active lateral secondary suspension for railway vehicles. The conditions for energy balance are analysed and the relationship between the ride quality improvement and energy consumption is discussed in detail. The modal skyhook control is applied to analyse the energy consumption of this suspension by separating its dynamics into the lateral and yaw modes, and based on a simplified model, the average power consumption of actuators is computed in frequency domain by using the power spectral density of lateral alignment of track irregularities. Then the impact of control gains and actuators' key parameters on the performance for both vibration suppressing and energy recovery/storage is analysed. Computer simulation is used to verify the obtained energy balance condition and to demonstrate that the improved ride comfort is achieved by this self-powered active suspension without any external power supply.

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

PubMed

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 (<20 cP) and lowest syringe injection glide force (<15 N) at mAb concentrations as high as 333 mg/mL (500 mg powder/mL). Inverse gas chromatography analysis indicated that the vehicle was the most important factor impacting suspension performance. Ethyl lactate rendered greater heat of sorption (suggesting strong particle-suspension vehicle interaction may reduce particle-particle self-association, leading to low suspension viscosity and glide force) but lacked the physical suspension stability exhibited by the other vehicles. Specific mixtures of ethyl lactate and 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.

Survey of Technical Preventative Measures to Reduce Whole-Body Vibration Effects when Designing Mobile Machinery

NASA Astrophysics Data System (ADS)

DONATI, P.

2002-05-01

Engineering solutions to minimize the effects on operators of vibrating mobile machinery can be conveniently grouped into three areas: Reduction of vibration at source by improvement of the quality of terrain, careful selection of vehicle or machine, correct loading, proper maintenance, etc.Reduction of vibration transmission by incorporating suspension systems (tyres, vehicle suspensions, suspension cab and seat) between the operator and the source of vibration.Improvement of cab ergonomics and seat profiles to optimize operator posture. These paper reviews the different techniques and problems linked to categories (2) and (3). According to epidemiological studies, the main health risk with whole-body vibration exposure would appear to be lower back pain. When designing new mobile machinery, all factors which may contribute to back injury should be considered in order to reduce risk. For example, optimized seat suspension is useless if the suspension seat cannot be correctly and easily adjusted to the driver's weight or if the driver is forced to drive in a bent position to avoid his head striking the ceiling due to the spatial requirement of the suspension seat.

Physical transformation of niclosamide solvates in pharmaceutical suspensions determined by DSC and TG analysis.

PubMed

de Villiers, M M; Mahlatji, M D; Malan, S F; van Tonder, E C; Liebenberg, W

2004-07-01

This study reports the preparation of four niclosamide solvates and the determination of the stability of the crystal forms in different suspension vehicles by DSC and TG analysis. Thermal analysis showed that the niclosamide solvates were extremely unstable in a PVP-vehicle and rapidly changed to monohydrated crystals. A suspension in propylene glycol was more stable and TG analysis showed that crystal transformation was less rapid. In this vehicle, the crystals transformed to the anhydrate, rather than the monohydrate, since the vehicle was non-aqueous. The TEG-hemisolvate was the most stable in suspension and offered the best possibility of commercial exploitation.

Study on kinematic and compliance test of suspension

NASA Astrophysics Data System (ADS)

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.

Traffic accident simulation : final report.

DOT National Transportation Integrated Search

1992-06-01

The purpose of this research was to determine if HVOSM (Highway Vehicle Object Simulation Model) could be used to model a vehicle with a modern front (or rear) suspension system such as a McPherson strut and have the results of the dynamic model be v...

26 CFR 41.4481-2 - Persons liable for tax.

Code of Federal Regulations, 2010 CFR

2010-04-01

... period; (B) In the case of a vehicle under a suspension of tax described in § 41.4483-3(a), at the time... to whether there was in effect, at the time the vehicle was acquired, a suspension under § 41.4483-3... prior taxable use of the vehicle and whether there was a suspension of tax in the taxable period. If the...

A neural-network-based model for the dynamic simulation of the tire/suspension system while traversing road irregularities.

PubMed

Guarneri, Paolo; Rocca, Gianpiero; Gobbi, Massimiliano

2008-09-01

This paper deals with the simulation of the tire/suspension dynamics by using recurrent neural networks (RNNs). RNNs are derived from the multilayer feedforward neural networks, by adding feedback connections between output and input layers. The optimal network architecture derives from a parametric analysis based on the optimal tradeoff between network accuracy and size. The neural network can be trained with experimental data obtained in the laboratory from simulated road profiles (cleats). The results obtained from the neural network demonstrate good agreement with the experimental results over a wide range of operation conditions. The NN model can be effectively applied as a part of vehicle system model to accurately predict elastic bushings and tire dynamics behavior. Although the neural network model, as a black-box model, does not provide a good insight of the physical behavior of the tire/suspension system, it is a useful tool for assessing vehicle ride and noise, vibration, harshness (NVH) performance due to its good computational efficiency and accuracy.

Study on figure-eight-shaped coil electrodynamic suspension magnetic levitation systems without cross-connection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ribani, P.L.; Urbano, N.

2000-01-01

Two figure-eight-shaped coils for electrodynamic suspension (EDS) magnetic levitation (MAGLEV) systems without cross-connection are proposed and analyzed. The guideway coils are positioned under the MAGLEV vehicle; they are parallel to the horizontal plane. The interaction of a magnetic module on the vehicle, composed of three or four superconducting (SC) coils, with a guideway module, comprised of two figure-eight coils, is studied by means of the dynamic circuit theory. The currents in the SC coils are supposed to be constant in time while they move as a rigid body, with a constant velocity. Some results are presented and compared with thosemore » for a standard side-wall cross-connected system.« less

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

NASA Technical Reports Server (NTRS)

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.

Advanced Suspension and Control Algorithm for U.S. Army Ground Vehicles

DTIC Science & Technology

2013-04-01

Army Materiel Systems Analysis Activity (AMSAA), for his assistance and guidance in building a multibody vehicle dynamics model of a typical light...Mobility Multipurpose Wheeled Vehicle [HMMWV] model) that was developed in collaboration with the U.S. Army Materiel Systems Analysis Activity (5) is...control weight for GPC With Explicit Disturbance was R = 1.0e-7 over the entire speed range. To simplify analysis , the control weights for the other two

Oesophageal bioadhesion of sodium alginate suspensions: particle swelling and mucosal retention.

PubMed

Richardson, J Craig; Dettmar, Peter W; Hampson, Frank C; Melia, Colin D

2004-09-01

This paper describes a prospective bioadhesive liquid dosage form designed to specifically adhere to the oesophageal mucosa. It contains a swelling polymer, sodium alginate, suspended in a water-miscible vehicle and is activated by dilution with saliva to form an adherent layer of polymer on the mucosal surface. The swelling of alginate particles and the bioadhesion of 40% (w/w) sodium alginate suspensions were investigated in a range of vehicles: glycerol, propylene glycol, PEG 200 and PEG 400. Swelling of particles as a function of vehicle dilution with artificial saliva was quantified microscopically using 1,9-dimethyl methylene blue (DMMB) as a visualising agent. The minimum vehicle dilution to initiate swelling varied between vehicles: glycerol required 30% (w/w) dilution whereas PEG 400 required nearly 60% (w/w). Swelling commenced when the Hildebrand solubility parameter of the diluted vehicle was raised to 37 MPa(1/2). The bioadhesive properties of suspensions were examined by quantifying the amount of sodium alginate retained on oesophageal mucosa after washing in artificial saliva. Suspensions exhibited considerable mucoretention and strong correlations were obtained between mucosal retention, the minimum dilution to initiate swelling, and the vehicle Hildebrand solubility parameter. These relationships may allow predictive design of suspensions with specific mucoretentive properties, through judicious choice of vehicle characteristics.

49 CFR 396.3 - Inspection, repair, and maintenance.

Code of Federal Regulations, 2010 CFR

2010-10-01

... systematically inspected, repaired, and maintained, all motor vehicles and intermodal equipment subject to its... affect safety of operation, including but not limited to, frame and frame assemblies, suspension systems... cause to be maintained, records for each motor vehicle they control for 30 consecutive days. Intermodal...

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

NASA Astrophysics Data System (ADS)

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.

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

NASA Astrophysics Data System (ADS)

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.

Wind tunnel magnetic Suspension Systems at the University of Southampton, England

NASA Technical Reports Server (NTRS)

Goodyer, Michael J.

1992-01-01

The magnetic suspension system at Southampton University was used in two roles: as a device for producing useful aerodynamic data, and as a vehicle to develop and demonstrate new technology for application to a projected larger facility. Examples of both follow, beginning with an outline of the quest to develop methods for reaching high angles of attack because of current interest in researching the associated aerodynamics.

A nonlinear kinematic and dynamic modeling of Macpherson suspension systems with a magneto-rheological damper

NASA Astrophysics Data System (ADS)

Dutta, Saikat; Choi, Seung-Bok

2016-03-01

It is well known that Macpherson strut suspension systems are widely used in light and medium weight vehicles. The performance of these suspension systems can be enriched by incorporating magneto-rheological (MR) dampers and an appropriate dynamic model is required in order to find out the ride comfort and other performances properly in the sense of practical environment conditions. Therefore, in this work the kinematic and dynamic modeling of Macpherson strut suspension system with MR damper is presented and its responses are evaluated. The governing equations are formulated using the kinematic properties of the suspension system and adopting Lagrange’s equation. In the formulation of the model, both the rotation of the wheel assembly and the lateral stiffness of the tire are considered to represent the nonlinear characteristic of Macpherson type suspension system. The formulated mathematical model is then compared with equivalent conventional quarter car suspension model and the different dynamic responses such as the displacement of the sprung mass are compared to emphasize the effectiveness of the proposed model. Additionally, in this work the important kinematic properties of suspension system such as camber angle, king-pin angle and track width alteration, which cannot be obtained from conventional quarter car suspension model, are evaluated in time and frequency domains. Finally, vibration control responses of the proposed suspension system are presented in time and frequency domains which are achieved from the semi-active sky-hook controller.

Comfort-oriented vehicle suspension design with skyhook inerter configuration

NASA Astrophysics Data System (ADS)

Hu, Yinlong; Chen, Michael Z. Q.; Sun, Yonghui

2017-09-01

This paper is concerned with the comfort-oriented vehicle suspension design problem by using a skyhook inerter configuration. The rationale of the skyhook inerter is to use a grounded inerter to virtually increase the sprung mass of a vehicle, as it is analytically demonstrated that increasing the sprung mass can always improve the ride comfort performance. Semi-active means to realize the skyhook inerter configuration are investigated by using semi-active inerters. Three control laws, that is the on-off control, the anti-chatter on-off control, and the continuous control, are proposed for the semi-active inerter to approximate the skyhook inerter. Numerical simulations are performed to demonstrate the effectiveness and performances of these control laws. It is shown that the semi-active realizations of the skyhook inerter by using the proposed control laws can achieve over 10% improvement compared with the traditional strut, and similar performances are obtained for these control laws, with slight differences with respect to different static stiffnesses of the suspension system.

A forecast of new test capabilities using Magnetic Suspension and Balance Systems

NASA Technical Reports Server (NTRS)

Lawing, Pierce L.; Johnson, William G., Jr.

1988-01-01

This paper outlines the potential of Magnetic Suspension and Balance System (MSBS) technology to solve existing problems related to support interference in wind tunnels. Improvement of existing test techniques and exciting new techniques are envisioned as a result of applying MSBS. These include improved data accuracy, dynamic stability testing, two-body/stores release testing, and pilot/designer-in-the-loop tests. It also discusses the use of MSBS for testing exotic configurations such as hybrid hypersonic vehicles. A new facility concept that combines features of ballistic tubes, magnetic suspension, and cryogenic tunnels is described.

Analysis of the stability of nonlinear suspension system with slow-varying sprung mass under dual-excitation

NASA Astrophysics Data System (ADS)

Yao, Jun; Zhang, Jinqiu; Zhao, Mingmei; Li, Xin

2018-07-01

This study investigated the stability of vibration in a nonlinear suspension system with slow-varying sprung mass under dual-excitation. A mathematical model of the system was first established and then solved using the multi-scale method. Finally, the amplitude-frequency curve of vehicle vibration, the solution's stable region and time-domain curve in Hopf bifurcation were derived. The obtained results revealed that an increase in the lower excitation would reduce the system's stability while an increase in the upper excitation can make the system more stable. The slow-varying sprung mass will change the system's damping from negative to positive, leading to the appearance of limit cycle and Hopf bifurcation. As a result, the vehicle's vibration state is forced to change. The stability of this system is extremely fragile under the effect of dynamic Hopf bifurcation as well as static bifurcation.

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

NASA Astrophysics Data System (ADS)

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.

23 CFR 1275.4 - Compliance criteria.

Code of Federal Regulations, 2010 CFR

2010-04-01

...'s license suspension of not less than one year; (2) Be subject to either— (i) The impoundment of each of the driver's motor vehicles during the one-year license suspension; (ii) The immobilization of each of the driver's motor vehicles during the one-year license suspension; or (iii) The installation...

Magnetic levitation configuration incorporating levitation, guidance and linear synchronous motor

DOEpatents

Coffey, H.T.

1993-10-19

A propulsion and suspension system for an inductive repulsion type magnetically levitated vehicle which is propelled and suspended by a system which includes propulsion windings which form a linear synchronous motor and conductive guideways, adjacent to the propulsion windings, where both combine to partially encircling the vehicle-borne superconducting magnets. A three phase power source is used with the linear synchronous motor to produce a traveling magnetic wave which in conjunction with the magnets propel the vehicle. The conductive guideway combines with the superconducting magnets to provide for vehicle levitation. 3 figures.

Magnetic levitation configuration incorporating levitation, guidance and linear synchronous motor

DOEpatents

Coffey, Howard T.

1993-01-01

A propulsion and suspension system for an inductive repulsion type magnetically levitated vehicle which is propelled and suspended by a system which includes propulsion windings which form a linear synchronous motor and conductive guideways, adjacent to the propulsion windings, where both combine to partially encircling the vehicle-borne superconducting magnets. A three phase power source is used with the linear synchronous motor to produce a traveling magnetic wave which in conjunction with the magnets propel the vehicle. The conductive guideway combines with the superconducting magnets to provide for vehicle leviation.

Off-road motorbike performance analysis using a rear semi-active suspension

NASA Astrophysics Data System (ADS)

Lozoya-Santos, Jorge de J.; Cervantes-Muñoz, Damián.; Ramírez Mendoza, Ricardo

2015-04-01

The topic of this paper is the analysis of a control system for a semi active rear suspension in an off-road 2-wheel vehicle. Several control methods are studied, as well as the recently proposed Frequency Estimation Based (FEB) algorithm. The test motorcycle dynamics, as well as the passive, semi active, and the algorithm controlled shock absorber models are loaded into BikeSim, a professional two-wheeled vehicle simulation software, and tested in several road conditions. The results show a detailed comparison of the theoretical performance of the different control approaches in a novel environment for semi active dampers.

Superelement model based parallel algorithm for vehicle dynamics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agrawal, O.P.; Danhof, K.J.; Kumar, R.

1994-05-01

This paper presents a superelement model based parallel algorithm for a planar vehicle dynamics. The vehicle model is made up of a chassis and two suspension systems each of which consists of an axle-wheel assembly and two trailing arms. In this model, the chassis is treated as a Cartesian element and each suspension system is treated as a superelement. The parameters associated with the superelements are computed using an inverse dynamics technique. Suspension shock absorbers and the tires are modeled by nonlinear springs and dampers. The Euler-Lagrange approach is used to develop the system equations of motion. This leads tomore » a system of differential and algebraic equations in which the constraints internal to superelements appear only explicitly. The above formulation is implemented on a multiprocessor machine. The numerical flow chart is divided into modules and the computation of several modules is performed in parallel to gain computational efficiency. In this implementation, the master (parent processor) creates a pool of slaves (child processors) at the beginning of the program. The slaves remain in the pool until they are needed to perform certain tasks. Upon completion of a particular task, a slave returns to the pool. This improves the overall response time of the algorithm. The formulation presented is general which makes it attractive for a general purpose code development. Speedups obtained in the different modules of the dynamic analysis computation are also presented. Results show that the superelement model based parallel algorithm can significantly reduce the vehicle dynamics simulation time. 52 refs.« less

Oesophageal bioadhesion of sodium alginate suspensions 2. Suspension behaviour on oesophageal mucosa.

PubMed

Richardson, J Craig; Dettmar, Peter W; Hampson, Frank C; Melia, Colin D

2005-01-01

Sodium alginate suspensions in a range of water miscible vehicles were investigated as novel bioadhesive liquids for targeting the oesophageal mucosa. Such a dosage form might be utilised to coat the oesophageal surface and provide a protective barrier against gastric reflux, or to deliver therapeutic agents site-specifically. Alginate suspensions swelled and formed an adherent viscous layer on contact with the mucosa. The swelling kinetics of alginate particles on the oesophageal surface was examined with respect to vehicle composition and related to the extent, duration and location of bioadhesion within the oesophagus. Mucosal retention was evaluated in two in vitro models utilising tissue immersion and a peristaltic tube. By varying the vehicle composition it was possible to modulate the rate of swelling of alginate particles on the mucosa and the mucosal retention of suspensions. Suspensions containing predominantly glycerol exhibited superior retention and were preferentially retained within the lower oesophagus. The propensity of these suspensions to rapidly swell on the mucosa and establish adhesive/cohesive bonds may explain their enhanced retention. The potential to control, through vehicle composition, the extent, duration and location of oesophageal retention could provide a useful tool for site targeting of viscous polymers to the oesophagus.

Comparison between different sets of suspension parameters and introduction of new modified skyhook control strategy incorporating varying road condition

NASA Astrophysics Data System (ADS)

Abul Kashem, Saad Bin; Ektesabi, Mehran; Nagarajah, Romesh

2012-07-01

This study examines the uncertainties in modelling a quarter car suspension system caused by the effect of different sets of suspension parameters of a corresponding mathematical model. To overcome this problem, 11 sets of identified parameters of a suspension system have been compared, taken from the most recent published work. From this investigation, a set of parameters were chosen which showed a better performance than others in respect of peak amplitude and settling time. These chosen parameters were then used to investigate the performance of a new modified continuous skyhook control strategy with adaptive gain that dictates the vehicle's semi-active suspension system. The proposed system first captures the road profile input over a certain period. Then it calculates the best possible value of the skyhook gain (SG) for the subsequent process. Meanwhile the system is controlled according to the new modified skyhook control law using an initial or previous value of the SG. In this study, the proposed suspension system is compared with passive and other recently reported skyhook controlled semi-active suspension systems. Its performances have been evaluated in terms of ride comfort and road handling performance. The model has been validated in accordance with the international standards of admissible acceleration levels ISO2631 and human vibration perception.

The Annular Suspension and Pointing System /ASPS/

NASA Technical Reports Server (NTRS)

Anderson, W. W.; Woolley, C. T.

1978-01-01

The Annular Suspension and Pointing System (ASPS) may be attached to a carrier vehicle for orientation, mechanical isolation, and fine pointing purposes applicable to space experiments. It has subassemblies for both coarse and vernier pointing. A fourteen-degree-of-freedom simulation of the ASPS mounted on a Space Shuttle has yielded initial performance data. The simulation describes: the magnetic actuators, payload sensors, coarse gimbal assemblies, control algorithms, rigid body dynamic models of the payload and Shuttle, and a control system firing model.

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

PubMed

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.

40 CFR 86.1114-87 - Suspension and voiding of certificates of conformity.

Code of Federal Regulations, 2010 CFR

2010-07-01

...-Duty Vehicles, Including Light-Duty Trucks § 86.1114-87 Suspension and voiding of certificates of... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Suspension and voiding of certificates... AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND...

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

NASA Astrophysics Data System (ADS)

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.

i3Drive, a 3D interactive driving simulator.

PubMed

Ambroz, Miha; Prebil, Ivan

2010-01-01

i3Drive, a wheeled-vehicle simulator, can accurately simulate vehicles of various configurations with up to eight wheels in real time on a desktop PC. It presents the vehicle dynamics as an interactive animation in a virtual 3D environment. The application is fully GUI-controlled, giving users an easy overview of the simulation parameters and letting them adjust those parameters interactively. It models all relevant vehicle systems, including the mechanical models of the suspension, power train, and braking and steering systems. The simulation results generally correspond well with actual measurements, making the system useful for studying vehicle performance in various driving scenarios. i3Drive is thus a worthy complement to other, more complex tools for vehicle-dynamics simulation and analysis.

The Enabler: A concept for a lunar work vehicle

NASA Technical Reports Server (NTRS)

Brazell, James W.; Campbell, Craig; Kaser, Ken; Austin, James A.; Beard, Clark; Ceniza, Glenn; Hamby, Thomas; Robinson, Anne; Wooters, Dana

1992-01-01

The Enabler is an earthbound prototype designed to model an actual lunar work vehicle and is able to perform many of the tasks that might be expected of a lunar work vehicle. The vehicle will be constructed entirely from parts made by students and from standard stock parts. The design utilizes only four distinct chassis pieces and sixteen moving parts. The Enabler has non-orthogonal articulating joints that give the vehicle a wide range of mobility and reduce the total number of parts. Composite wheels provide the primary suspension system for the vehicle.

The Design and Performance Evaluation of Hydroformed Tubular Torsion Beam Axle

NASA Astrophysics Data System (ADS)

Kim, Jaehyun; Oh, Jinho; Choi, Hanho

2010-06-01

Suspensions for vehicles are structural devices used for suspending a vehicle body and absorbing shocks from the road. Thus, the suspensions must be designed such that they can attenuate shocks from a road and make passengers feel comfortable despite the shocks, and improve steering stability, determined by the ground contact force of tires during running of vehicles. Another important factor to be considered while designing suspensions is that the suspensions must maintain desired stiffness and desired durability despite the repeated application of shocks from roads thereto. The present relates, in general, to a tubular torsion beam for rear suspensions of vehicles and a manufacturing method thereof and, more particularly, to the provision of tubular torsion beams having excellent roll stiffness and excellent roll strength, produced through hydroforming. The hydroforming technology has a lot of benefit which is shape accuracy, good durability caused by compressive pressure, and good forming quality. In this study, the performance evaluation of the hydroformed tubular torsion beam axle is evaluated.

A hybrid approach to modeling and control of vehicle height for electronically controlled air suspension

NASA Astrophysics Data System (ADS)

Sun, Xiaoqiang; Cai, Yingfeng; Wang, Shaohua; Liu, Yanling; Chen, Long

2016-01-01

The control problems associated with vehicle height adjustment of electronically controlled air suspension (ECAS) still pose theoretical challenges for researchers, which manifest themselves in the publications on this subject over the last years. This paper deals with modeling and control of a vehicle height adjustment system for ECAS, which is an example of a hybrid dynamical system due to the coexistence and coupling of continuous variables and discrete events. A mixed logical dynamical (MLD) modeling approach is chosen for capturing enough details of the vehicle height adjustment process. The hybrid dynamic model is constructed on the basis of some assumptions and piecewise linear approximation for components nonlinearities. Then, the on-off statuses of solenoid valves and the piecewise approximation process are described by propositional logic, and the hybrid system is transformed into the set of linear mixed-integer equalities and inequalities, denoted as MLD model, automatically by HYSDEL. Using this model, a hybrid model predictive controller (HMPC) is tuned based on online mixed-integer quadratic optimization (MIQP). Two different scenarios are considered in the simulation, whose results verify the height adjustment effectiveness of the proposed approach. Explicit solutions of the controller are computed to control the vehicle height adjustment system in realtime using an offline multi-parametric programming technology (MPT), thus convert the controller into an equivalent explicit piecewise affine form. Finally, bench experiments for vehicle height lifting, holding and lowering procedures are conducted, which demonstrate that the HMPC can adjust the vehicle height by controlling the on-off statuses of solenoid valves directly. This research proposes a new modeling and control method for vehicle height adjustment of ECAS, which leads to a closed-loop system with favorable dynamical properties.

Ride comfort enhancement in railway vehicle by the reduction of the car body structural flexural vibration

NASA Astrophysics Data System (ADS)

Dumitriu, M.

2017-08-01

The paper approaches the issue of reduction in the vertical bending vibrations of the railway vehicle carbody and the ride comfort enhancement at high velocities, starting from the prospect of isolating the vibrations by the best possible selection of the passive suspension damping in the vehicle. To this purpose, the examination falls on the influence of the vertical suspension damping upon the vibrations regime of the vehicle at the bending resonance frequency and upon the ride comfort. The results of the numerical simulations regarding the frequency response of the carbody acceleration and the comfort index will be therefore used. A value of the secondary suspension damping can be thus identified that will provide the best ride comfort performance. Similarly, the ride comfort can be increased by raising the primary suspension damping ratio.

Application of an Integrated HPC Reliability Prediction Framework to HMMWV Suspension System

DTIC Science & Technology

2010-09-13

model number M966 (TOW Missle Carrier, Basic Armor without weapons), since they were available. Tires used for all simulations were the bias-type...vehicle fleet, including consideration of all kinds of uncertainty, especially including model uncertainty. The end result will be a tool to use...building an adequate vehicle reliability prediction framework for military vehicles is the accurate modeling of the integration of various types of

Assessment of railway wagon suspension characteristics

NASA Astrophysics Data System (ADS)

Soukup, Josef; Skočilas, Jan; Skočilasová, Blanka

2017-05-01

The article deals with assessment of railway wagon suspension characteristics. The essential characteristics of a suspension are represented by the stiffness constants of the equivalent springs and the eigen frequencies of the oscillating movements in reference to the main central inertia axes of a vehicle. The premise of the experimental determination of these characteristic is the knowledge of the gravity center position and the knowledge of the main central inertia moments of the vehicle frame. The vehicle frame performs the general spatial movement when the vehicle moves. An analysis of the frame movement generally arises from Euler's equations which are commonly used for the description of the spherical movement. This solution is difficult and it can be simplified by applying the specific assumptions. The eigen frequencies solutions and solutions of the suspension stiffness are presented in the article. The solutions are applied on the railway and road vehicles with the simplifying conditions. A new method which assessed the characteristics is described in the article.

Mechanical Design Engineering Enabler Project wheel and wheel drives

NASA Technical Reports Server (NTRS)

Nutt, Richard E.; Couch, Britt K.; Holley, John L., Jr.; Garris, Eric S.; Staut, Paul V.

1992-01-01

Our group was assigned the responsibility of designing the wheel and wheel drive system for a proof-of-concept model of the lunar-based ENABLER. ENABLER is a multi-purpose, six wheeled vehicle designed to lift and transport heavy objects associated with the construction of a lunar base. The resulting design was based on the performance criteria of the ENABLER. The drive system was designed to enable the vehicle to achieve a speed of 7 mph on a level surface, climb a 30 percent grade, and surpass a one meter high object and one meter wide crevice. The wheel assemblies were designed to support the entire weight of the vehicle on two wheels. The wheels were designed to serve as the main component of the vehicle's suspension and will provide suitable traction for lunar-type surfaces. The expected performance of the drive system for the ENABLER was influenced by many mechanical factors. The expected top speed on a level sandy surface is 4 mph instead of the desired 7 mph. This is due to a lack of necessary power at the wheels. The lack of power resulted from dimension considerations that allowed only an eight horsepower engine and also from mechanical inefficiencies of the hydraulic system. However, the vehicle will be able to climb a 30 percent grade, surpass a one meter high object and one meter wide crevice. The wheel assemblies will be able to support the entire weight of the vehicle on two wheels. The wheels will also provide adequate suspension for the vehicle and sufficient traction for lunar-type surfaces.

Development of a Retractable Compressible Fluid Suspension System. Task 1

DTIC Science & Technology

1988-06-01

the design and fabrication cost of the suspension units, the roadwheel hub and spindle currently used on the AAV -7AI amphibious vehicle dre to be...SUSPENSION HOUSING FIGURE .5. FEM HOUSING STRESS ANALYSIS, SOLID MODEL, SECTION VIEW -16- ,"~1 /IZ4: 45 "" / EAL UN ~iST=h~~ / 6DIE5.8la DTJJ.-RER.SUSP. HSC ...SHX M1784 DS=-792 IIDDEN - 9983 -1779 Ti___ 4869 5_ 6334 64959- 71784 DTli--RETR. SUSP. HSC .,CiASE1:HAX VERT, 29K OUT FIGURE 7. PIVOT SHAFT, SOLID

Naratriptan hydrochloride in extemporaneosly compounded oral suspensions.

PubMed

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 deg C and 90 days at 4 deg C. At least 96% of the inital concentration remained at all time points. Naratriptan hydrochloride extemporaneously prepared as oral suspensions from tablets in equal-parts mixtures of Ora-Plus suspension vehicle with Ora-Sweet and with Ora-Sweet SF syrups was pharmaceutically acceptable and chemically stable for at least seven days at 23 deg C and 90 days at 4 deg C. Syrpalta was unacceptable for use as a vehicle for naratriptan hydrochloride suspensions prepared from tablets.

Modelling generalisation and power dissipation of flexible-wheel suspension concept for planetary surface vehicles

NASA Astrophysics Data System (ADS)

Cao, Dongpu; Khajepour, Amir; Song, Xubin

2011-08-01

Flexible-wheel (FW) suspension concept has been regarded to be one of the novel technologies for future planetary surface vehicles (PSVs). This study develops generalised models for fundamental stiffness and damping properties and power consumption characteristics of the FW suspension with and without considering wheel-hub dimensions. Compliance rolling resistance (CRR) coefficient is also defined and derived for the FW suspension. Based on the generalised models and two dimensionless measures, suspension properties are analysed for two FW suspension configurations. The sensitivity analysis is performed to investigate the effects of the design parameters and operating conditions on the CRR and power consumption characteristic of the FW suspension. The modelling generalisation permits analyses of fundamental properties and power consumption characteristics of different FW suspension designs in a uniform and very convenient manner, which would serve as a theoretical foundation for the design of FW suspensions for future PSVs.

Stability and uniformity of extemporaneous preparations of voriconazole in two liquid suspension vehicles at two storage temperatures.

PubMed

Nguyen, Kyvan Q; Hawkins, Michelle G; Taylor, Ian T; Wiebe, Valerie J; Tell, Lisa A

2009-07-01

To determine the stability and distribution of voriconazole in 2 extemporaneously prepared (compounded) suspensions stored for 30 days at 2 temperatures. Voriconazole suspensions (40 mg/mL) compounded from commercially available 200-mg tablets suspended in 1 of 2 vehicles. One vehicle contained a commercially available suspending agent and a sweetening syrup in a 1:1 mixture (SASS). The other vehicle contained the suspending agent with deionized water in a 3:1 mixture (SADI). Voriconazole suspensions (40 mg/mL in 40-mL volumes) were compounded on day 0 and stored at room temperature (approx 21 degrees C) or refrigerated (approx 5 degrees C). To evaluate distribution, room-temperature aliquots of voriconazole were measured immediately after preparation. Refrigerated aliquots were measured after 3 hours of refrigeration. To evaluate stability, aliquots from each suspension were measured at approximately 7-day intervals for up to 30 days. Voriconazole concentration, color, odor, opacity, and pH were measured, and aerobic and anaerobic bacterial cultures were performed at various points. Drug distribution was uniform (coefficient of variation, < 5%) in both suspensions. On day 0, 87.8% to 93.0% of voriconazole was recovered; percentage recovery increased to between 95.1% and 100.8% by day 7. On subsequent days, up to day 30, percentage recovery was stable (> 90%) for all suspensions. The pH of each suspension did not differ significantly throughout the 30-day period. Storage temperature did not affect drug concentrations at any time, nor was bacterial growth obtained. Extemporaneously prepared voriconazole in SASS and SADI resulted in suspensions that remained stable for at least 30 days. Refrigerated versus room-temperature storage of the suspensions had no effect on drug stability.

A Constraint Embedding Approach for Complex Vehicle Suspension Dynamics

DTIC Science & Technology

2015-04-24

Complex Vehicle Suspension Dynamics ECCOMAS Thematic Conference on Multibody Dynamics 2015 Abhinandan Jain∗, Calvin Kuo#, Paramsothy Jayakumar †, Jonathan...Suspension Dynamics ECCOMAS Thematic Conference on Multibody Dynamics 2015 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6...13. SUPPLEMENTARY NOTES ECCOMAS Thematic Conference on Multibody Dynamics 2015, June 29-July 2, 2015, Barcelona, Catalonia, Spain 14. ABSTRACT See

Between simplicity and accuracy: Effect of adding modeling details on quarter vehicle model accuracy.

PubMed

Soong, Ming Foong; Ramli, Rahizar; Saifizul, Ahmad

2017-01-01

Quarter vehicle model is the simplest representation of a vehicle that belongs to lumped-mass vehicle models. It is widely used in vehicle and suspension analyses, particularly those related to ride dynamics. However, as much as its common adoption, it is also commonly accepted without quantification that this model is not as accurate as many higher-degree-of-freedom models due to its simplicity and limited degrees of freedom. This study investigates the trade-off between simplicity and accuracy within the context of quarter vehicle model by determining the effect of adding various modeling details on model accuracy. In the study, road input detail, tire detail, suspension stiffness detail and suspension damping detail were factored in, and several enhanced models were compared to the base model to assess the significance of these details. The results clearly indicated that these details do have effect on simulated vehicle response, but to various extents. In particular, road input detail and suspension damping detail have the most significance and are worth being added to quarter vehicle model, as the inclusion of these details changed the response quite fundamentally. Overall, when it comes to lumped-mass vehicle modeling, it is reasonable to say that model accuracy depends not just on the number of degrees of freedom employed, but also on the contributions from various modeling details.

Between simplicity and accuracy: Effect of adding modeling details on quarter vehicle model accuracy

PubMed Central

2017-01-01

Quarter vehicle model is the simplest representation of a vehicle that belongs to lumped-mass vehicle models. It is widely used in vehicle and suspension analyses, particularly those related to ride dynamics. However, as much as its common adoption, it is also commonly accepted without quantification that this model is not as accurate as many higher-degree-of-freedom models due to its simplicity and limited degrees of freedom. This study investigates the trade-off between simplicity and accuracy within the context of quarter vehicle model by determining the effect of adding various modeling details on model accuracy. In the study, road input detail, tire detail, suspension stiffness detail and suspension damping detail were factored in, and several enhanced models were compared to the base model to assess the significance of these details. The results clearly indicated that these details do have effect on simulated vehicle response, but to various extents. In particular, road input detail and suspension damping detail have the most significance and are worth being added to quarter vehicle model, as the inclusion of these details changed the response quite fundamentally. Overall, when it comes to lumped-mass vehicle modeling, it is reasonable to say that model accuracy depends not just on the number of degrees of freedom employed, but also on the contributions from various modeling details. PMID:28617819

Investigation on dynamical interaction between a heavy vehicle and road pavement

NASA Astrophysics Data System (ADS)

Yang, Shaopu; Li, Shaohua; Lu, Yongjie

2010-08-01

This paper presents a model for three-dimensional, heavy vehicle-pavement-foundation coupled system, which is modelled as a seven-DOF vehicle moving along a simply supported double-layer rectangular thin plate on a linear viscoelastic foundation. The vertical tyre force is described by a single point-contact model, while the pavement-foundation is modelled as a double-layer plate on a linear viscoelastic foundation. Using the Galerkin method and quick direct integral method, the dynamical behaviour of the vehicle-pavement-foundation coupled system is investigated numerically and compared with that of traditional vehicle system and pavement system. The effects of coupling action on vehicle body vertical acceleration, suspension deformations, tyre forces and pavement displacements are also obtained. The investigation shows that the coupling action could not be neglected even on a smooth road surface, such as highway. Thus, it is necessary to investigate the dynamics of vehicle and pavement simultaneously based on the vehicle-pavement-foundation coupled system.

32 CFR 634.46 - Point system procedures.

Code of Federal Regulations, 2011 CFR

2011-07-01

... CRIMINAL INVESTIGATIONS MOTOR VEHICLE TRAFFIC SUPERVISION Driving Records and the Traffic Point System § 634.46 Point system procedures. (a) Reports of moving traffic violations recorded on DD Form 1408 or... traffic points or the suspension or revocation of driving privileges on the person's driving record...

32 CFR 634.46 - Point system procedures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... CRIMINAL INVESTIGATIONS MOTOR VEHICLE TRAFFIC SUPERVISION Driving Records and the Traffic Point System § 634.46 Point system procedures. (a) Reports of moving traffic violations recorded on DD Form 1408 or... traffic points or the suspension or revocation of driving privileges on the person's driving record...

Vehicle systems: coupled and interactive dynamics analysis

NASA Astrophysics Data System (ADS)

Vantsevich, Vladimir V.

2014-11-01

This article formulates a new direction in vehicle dynamics, described as coupled and interactive vehicle system dynamics. Formalised procedures and analysis of case studies are presented. An analytical consideration, which explains the physics of coupled system dynamics and its consequences for dynamics of a vehicle, is given for several sets of systems including: (i) driveline and suspension of a 6×6 truck, (ii) a brake mechanism and a limited slip differential of a drive axle and (iii) a 4×4 vehicle steering system and driveline system. The article introduces a formal procedure to turn coupled system dynamics into interactive dynamics of systems. A new research direction in interactive dynamics of an active steering and a hybrid-electric power transmitting unit is presented and analysed to control power distribution between the drive axles of a 4×4 vehicle. A control strategy integrates energy efficiency and lateral dynamics by decoupling dynamics of the two systems thus forming their interactive dynamics.

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

NASA Astrophysics Data System (ADS)

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.

An approach for multi-objective optimization of vehicle suspension system

NASA Astrophysics Data System (ADS)

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.

Lateral Stability and Steady State Curving Performance of Unconventional Rail Trucks

NASA Astrophysics Data System (ADS)

Dukkipati, Rao V.; Narayanaswamy, Srinivasan

Conventional railway vehicle systems exhibit hunting phenomenon which increases component wear and imposes operating speed limits. There is also a conflict between dynamic stability and the ability of the vehicle to steer around curves. Alternatively, independently rotating wheels (IRW) in a wheelset eliminate hunting but the wheelset guidance set capability is lost. A compromise solution is made possible by a modified design that exploits a lack of fore-and-aft symmetry in the suspension design. A comparative study on steady state curving performance and dynamic stability of some unconventional truck designs is carried out. The effects of suspension and conicity are considered to evaluate the trade-off between dynamic stability and curving performance.

About the preliminary design of the suspension spring and shock absorber

NASA Astrophysics Data System (ADS)

Preda, I.

2016-08-01

The aim of this paper is to give some recommendation for the design of main-spring and shock absorber of motor vehicle suspensions. Starting from a 2DoF model, the suspension parameters are transferred on the real vehicle on the base of planar schemes for the linkage. For the coil spring, the equations that must be fulfilled simultaneously permit to calculate three geometrical parameters. The indications presented for the shock absorber permit to obtain the damping coefficients in the compression and rebound strokes and to calculate the power dissipated during the vehicle oscillatory movement.

Multi-limbed locomotion systems for space construction and maintenance

NASA Technical Reports Server (NTRS)

Waldron, K. J.; Klein, C. A.

1987-01-01

A well developed technology of coordination of multi-limbed locomotory systems is now available. Results from a NASA sponsored study of several years ago are presented. This was a simulation study of a three-limbed locomotion/manipulation system. Each limb had six degrees of freedom and could be used either as a locomotory grasping hand-holds, or as a manipulator. The focus of the study was kinematic coordination algorithms. The presentation will also include very recent results from the Adaptive Suspension Vehicle Project. The Adaptive Suspension Vehicle (ASV) is a legged locomotion system designed for terrestrial use which is capable of operating in completely unstructured terrain in either a teleoperated or operator-on-board mode. Future development may include autonomous operation. The ASV features a very advanced coordination and control system which could readily be adapted to operation in space. An inertial package with a vertical gyro, and rate gyros and accelerometers on three orthogonal axes provides body position information at high bandwidth. This is compared to the operator's commands, injected via a joystick to provide a commanded force system on the vehicle's body. This system is, in turn, decomposed by a coordination algorithm into force commands to those legs which are in contact with the ground.

32 CFR 634.46 - Point system procedures.

Code of Federal Regulations, 2013 CFR

2013-07-01

... CRIMINAL INVESTIGATIONS MOTOR VEHICLE TRAFFIC SUPERVISION Driving Records and the Traffic Point System... traffic points or the suspension or revocation of driving privileges on the person's driving record... or driving privileges suspended or revoked when the report of action taken indicates that neither...

32 CFR 634.46 - Point system procedures.

Code of Federal Regulations, 2012 CFR

2012-07-01

... CRIMINAL INVESTIGATIONS MOTOR VEHICLE TRAFFIC SUPERVISION Driving Records and the Traffic Point System... traffic points or the suspension or revocation of driving privileges on the person's driving record... or driving privileges suspended or revoked when the report of action taken indicates that neither...

32 CFR 634.46 - Point system procedures.

Code of Federal Regulations, 2014 CFR

2014-07-01

... CRIMINAL INVESTIGATIONS MOTOR VEHICLE TRAFFIC SUPERVISION Driving Records and the Traffic Point System... traffic points or the suspension or revocation of driving privileges on the person's driving record... or driving privileges suspended or revoked when the report of action taken indicates that neither...

Computer analysis of railcar vibrations

NASA Technical Reports Server (NTRS)

Vlaminck, R. R.

1975-01-01

Computer models and techniques for calculating railcar vibrations are discussed along with criteria for vehicle ride optimization. The effect on vibration of car body structural dynamics, suspension system parameters, vehicle geometry, and wheel and rail excitation are presented. Ride quality vibration data collected on the state-of-the-art car and standard light rail vehicle is compared to computer predictions. The results show that computer analysis of the vehicle can be performed for relatively low cost in short periods of time. The analysis permits optimization of the design as it progresses and minimizes the possibility of excessive vibration on production vehicles.

Investigation into Improvement for Anti-Rollover Propensity of SUV

NASA Astrophysics Data System (ADS)

Xiong, Fei; Lan, Fengchong; Chen, Jiqing; Yang, Yuedong

2017-05-01

Currently, many research from domestic and foreign on improving anti-rollover performance of vehicle mainly focus on the electronic control of auxiliary equipment, do not make full use of suspension layout to optimize anti-rollover performance of vehicle. This investigation into anti-rollover propensity improvement concentrates on the vehicle parameters greatly influencing on anti-rollover propensity of vehicle. A simulation based on fishhook procedure is used to perform design trials and evaluations aimed at ensuring an optimal balance between vehicle's design parameters and various engineering capacities, the anti-rollover propensity is optimized at the detailed design stage of a new SUV model. Firstly a four-DOF theoretical kinematic model is established, then a complete multi-body dynamics model built in ADAMS/car based on the whole vehicle parameters is correlated to the objective handing and stability test results of a mule car. Secondly, in fishhook test simulations, the Design of Experiments method is used to quantify the effect of the vehicle parameters on the anti-rollover performance. By means of the simulation, the roll center height of front suspension should be more than 30 mm, that of rear suspension less than 150 mm, and the HCG less than 620 mm for the SUV. The ratio of front to rear suspension roll stiffness should be ranged from 1.4 to 1.6 for the SUV. As a result, at the detailed design stage of product, the anti-rollover performance of vehicle can be improved by optimizing chassis and integrated vehicle parameters.

Curiosity Wheel During Descent

NASA Image and Video Library

2012-08-07

This color thumbnail image was obtained by NASA Curiosity rover illustrating the first appearance of the left front wheel of the Curiosity rover after deployment of the suspension system as the vehicle was about to touch down on Mars.

Intelligent mobility for robotic vehicles in the army after next

NASA Astrophysics Data System (ADS)

Gerhart, Grant R.; Goetz, Richard C.; Gorsich, David J.

1999-07-01

The TARDEC Intelligent Mobility program addresses several essential technologies necessary to support the army after next (AAN) concept. Ground forces in the AAN time frame will deploy robotic unmanned ground vehicles (UGVs) in high-risk missions to avoid exposing soldiers to both friendly and unfriendly fire. Prospective robotic systems will include RSTA/scout vehicles, combat engineering/mine clearing vehicles, indirect fire artillery and missile launch platforms. The AAN concept requires high on-road and off-road mobility, survivability, transportability/deployability and low logistics burden. TARDEC is developing a robotic vehicle systems integration laboratory (SIL) to evaluate technologies and their integration into future UGV systems. Example technologies include the following: in-hub electric drive, omni-directional wheel and steering configurations, off-road tires, adaptive tire inflation, articulated vehicles, active suspension, mine blast protection, detection avoidance and evasive maneuver. This paper will describe current developments in these areas relative to the TARDEC intelligent mobility program.

TARDEC Ground Vehicle Robotics: Vehicle Dynamic Characterization and Research

DTIC Science & Technology

2015-09-01

inferred roll angles that are found with the IMU . This is usually done with UNCLASSIFIED UNCLASSIFIED linear potentiometers, which have an electrical...wire electric, Electric traction control. Suspension Styles: Suspension is what keeps the vehicle off the ground and mechanically isolated from the...lot” maneuvers. Because of this, they roll with no slip angles. This means that the steering angles of the front wheels must be calibrated perfectly

Influence of flocculating agents and structural vehicles on the physical stability and rheological behavior of nitrofurantoin suspension.

PubMed

Moghimipour, Eskandar; Salimi, Anayatollah; Rezaee, Saeed; Balack, Maryam; Handali, Somayeh

2014-05-01

Nitrofurantoin is a nitrofuran antibiotic that has been used for treatment of urinary tract against positive and negative bacteria. The aim of this study was to evaluate the effect of structural vehicles and flocculating agents on physical stability and rheological behavior of nitrofurantoin suspension. To formulate the suspensions, the effect of glycerin and polysorbate 80 as wetting agents was evaluated and their particle sizes were determined using the sieve method. Then to achieve controlled flocculation, sodium citrate and aluminum chloride were added. After choosing the suitable wetting and flocculating agents, structural vehicles such as sodium carboxyl methyl cellulose and Veegum were evaluated individually and in combination. In addition, the effect of sorbitol on density of continuous phase and some physical stability parameters such as sedimentation volume, degree of flocculation and ease of redispersion of the suspensions were evaluated. After incorporation of structural vehicles, the rheological properties of formulations were also determined to find their flow behavior. According to the results, glycerin (0.2%) and sodium citrate (0.3%) had the best effect on the suspension stability as wetting and flocculating agents, respectively. Rheological properties of formulations showed pseudoplastic behavior with some degree of thixotropy. In conclusion, the suspension containing Veegum 1%, sodium carboxy methyl cellulose 1%, glycerine 0.2%, sodium citrate 0.3% and sorbitol 20 % was chosen as the most physically stable formulation.

Passive damping in EDS maglev systems.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rote, D. M.

2002-05-03

There continues to be strong interest in the subjects of damping and drag forces associated with electrodynamic suspension (EDS) systems. While electromagnetic drag forces resist the forward motion of a vehicle and therefore consume energy, damping forces control, at least in part, the response of the vehicle to disturbances. Ideally, one would like to reduce the drag forces as much as possible while retaining adequate damping forces to insure dynamic stability and satisfactory ride quality. These two goals turn out to be difficult to achieve in practice. It is well known that maglev systems tend to be intrinsically under damped.more » Consequently it is often necessary in a practical system design to enhance the damping passively or actively. For reasons of cost and simplicity, it is desirable to rely as much as possible on passive damping mechanisms. In this paper, rough estimates are made of the passive damping and drag forces caused by various mechanisms in EDS systems. No attention will be given to active control systems or secondary suspension systems which are obvious ways to augment passive damping mechanisms if the latter prove to be inadequate.« less

Besifloxacin ophthalmic suspension 0.6% in patients with bacterial conjunctivitis: A multicenter, prospective, randomized, double-masked, vehicle-controlled, 5-day efficacy and safety study.

PubMed

Karpecki, Paul; Depaolis, Michael; Hunter, Judy A; White, Eric M; Rigel, Lee; Brunner, Lynne S; Usner, Dale W; Paterno, Michael R; Comstock, Timothy L

2009-03-01

Besifloxacin ophthalmic suspension 0.6% is a new topical fluoroquinolone for the treatment of bacterial conjunctivitis. Besifloxacin has potent in vitro activity against a broad spectrum of ocular pathogens, including drug-resistant strains. The primary objective of this study was to compare the clinical and microbiologic efficacy of besifloxacin ophthalmic suspension 0.6% with that of vehicle (the formulation without besifloxacin) in the treatment of bacterial conjunctivitis. This was a multicenter, prospective, randomized, double-masked, vehicle-controlled, parallel-group study in patients with acute bacterial conjunctivitis. Patients received either topical besifloxacin ophthalmic suspension or vehicle administered 3 times daily for 5 days. At study entry and on days 4 and 8 (visits 2 and 3), a clinical assessment of ocular signs and symptoms was performed in both eyes, as well as pinhole visual acuity testing, biomicroscopy, and culture of the infected eye(s). An ophthalmoscopic examination was performed at study entry and on day 8. The primary efficacy outcome measures were clinical resolution and eradication of the baseline bacterial infection on day 8 in culture-confirmed patients. The safety evaluation included adverse events, changes in visual acuity, and biomicroscopy and ophthalmoscopy findings in all patients who received at least 1 dose of active treatment or vehicle. The safety population consisted of 269 patients (mean [SD] age, 34.2 [22.3] years; 60.2% female; 82.5% white) with acute bacterial conjunctivitis. The culture-confirmed intent-to-treat population consisted of 118 patients (60 besifloxacin ophthalmic suspension, 58 vehicle). Significantly more patients receiving besifloxacin ophthalmic suspension than vehicle had clinical resolution of the baseline infection at visit 3 (44/60 [73.3%] vs 25/58 [43.1%], respectively; P < 0.001). Rates of bacterial eradication also were significantly greater with besifloxacin ophthalmic suspension compared with vehicle at visit 3 (53/60 [88.3%] vs35/58 [60.3%]; P < 0.001). The cumulative frequency of adverse events did not differ significantly between the 2 groups (69/137 [50.4%] and 70/132 [53.0%]). The most common ocular adverse events were eye pain (20/190 treated eyes [10.5%] and 13/188 [6.9%]), blurred vision (20/190 [10.5%] and 22/188 [11.7%]), and eye irritation (14/190 [7.4%] and 23/188 [12.2%]); these events were of mild or moderate severity. Changes in visual acuity and treatment-emergent events observed on biomicroscopy and direct ophthalmoscopy also were comparable between treatment groups. Besifloxacin ophthalmic suspension 0.6% given 3 times daily for 5 days was both efficacious and well tolerated compared with vehicle in the treatment of these patients with bacterial conjunctivitis. ClinicalTrials.gov Identifier: NCT00622908.

Applicability of CHSST Maglev technology for U.S. urban transportation

DOT National Transportation Integrated Search

2003-06-01

This report discusses the Chubu HSST technology applicability to U.S. urban transportation. This low speed system based on the principle of electromagnetic levitation by attractive suspension and propulsion by vehicle mounted linear induction motors ...

49 CFR 393.203 - Cab and body components.

Code of Federal Regulations, 2010 CFR

2010-10-01

... NECESSARY FOR SAFE OPERATION Frames, Cab and Body Components, Wheels, Steering, and Suspension Systems § 393... a roof exit. (b) Bolts or brackets securing the cab or the body of the vehicle to the frame shall...

Modernisation of a test rig for determination of vehicle shock absorber characteristics by considering vehicle suspension elements and unsprung masses

NASA Astrophysics Data System (ADS)

Maniowski, M.; Para, S.; Knapczyk, M.

2016-09-01

This paper presents a modernization approach of a standard test bench for determination of damping characteristics of automotive shock absorbers. It is known that the real-life work conditions of wheel-suspension dampers are not easy to reproduce in laboratory conditions, for example considering a high frequency damper response or a noise emission. The proposed test bench consists of many elements from a real vehicle suspension. Namely, an original tyre-wheel with additional unsprung mass, a suspension spring, an elastic top mount, damper bushings and a simplified wheel guiding mechanism. Each component was tested separately in order to identify its mechanical characteristics. The measured data serve as input parameters for a numerical simulation of the test bench behaviour by using a vibratory model with 3 degrees of freedom. Study on the simulation results and the measurements are needed for further development of the proposed test bench.

Multiphysics modelling of multibody systems: application to car semi-active suspensions

NASA Astrophysics Data System (ADS)

Docquier, N.; Poncelet, A.; Delannoy, M.; Fisette, P.

2010-12-01

The goal of the present article is to analyse the performances of a modern vehicle equipped with a novel suspension system linking front, rear, right and left cylinders via a semi-active hydraulic circuit, developed by the Tenneco Automotive company. In addition to improving the vehicle's vertical performances (in terms of comfort), both the stiff roll motion of the carbody and the soft wrap motion of the rear/front wheel-axle units can be obtained and tuned via eight electrovalves. The proposed system avoids the use of classical anti-roll bars, which would be incompatible with the wrap performance. A major problem of the project is to produce a realistic and efficient 3D multibody dynamic model of an Audi A6 coupled, at the equational level, with an hydraulic model of the suspension including cylinders, accumulators, valve characteristics, oil compressibility and pipe dynamics. As regards the hydraulic submodel, a particular attention is paid to assemble resistive components properly without resorting to the use of artificial volumes, as proposed by some software dealing with the dynamics of hydraulic systems. According to Tenneco Automotive requirements, this model must be produced in a Matlab/Simulink form, in particular for control purposes. Thanks to the symbolic approach underlying our multibody program; a unified hybrid model can be obtained as a unique plant dynamic block to be real-time integrated in the Simulink environment on a standard computer. Simulation results highlight the advantages of this new suspension system, in particular regarding the behaviour of the car which can remain stiff in roll for curve negotiation, while maintaining a soft wrap behaviour on uneven surfaces.

41 CFR 109-40.103-2 - Disqualification and suspension of carriers.

Code of Federal Regulations, 2010 CFR

2010-07-01

... suspension of carriers. 109-40.103-2 Section 109-40.103-2 Public Contracts and Property Management Federal... AVIATION, TRANSPORTATION, AND MOTOR VEHICLES 40-TRANSPORTATION AND TRAFFIC MANAGEMENT 40.1-General Provision § 109-40.103-2 Disqualification and suspension of carriers. Disqualification and suspension are...

The Challenges of Designing the Rocker-Bogie Suspension for the Mars Exploration Rover

NASA Technical Reports Server (NTRS)

Harrington, Brian D.; Voorhees, Chris

2004-01-01

Over the past decade, the rocker-bogie suspension design has become a proven mobility application known for its superior vehicle stability and obstacle-climbing capability. Following several technology and research rover implementations, the system was successfully flown as part of Mars Pathfinder s Sojourner rover. When the Mars Exploration Rover (MER) Project was first proposed, the use of a rocker-bogie suspension was the obvious choice due to its extensive heritage. The challenge posed by MER was to design a lightweight rocker-bogie suspension that would permit the mobility to stow within the limited space available and deploy into a configuration that the rover could then safely use to egress from the lander and explore the Martian surface. This paper will describe how the MER rocker-bogie suspension subsystem was able to meet these conflicting design requirements while highlighting the variety of deployment and latch mechanisms employed in the design.

Influence of unsprung weight on vehicle ride quality

NASA Astrophysics Data System (ADS)

Hrovat, D.

1988-08-01

In the first part of this paper, a simple quarter-car, two-degree-of-freedom (2 DOF) vehicle model is used to investigate potential benefits and adaptive control capabilities of active suspensions. The results of this study indicate that, with an active suspension, it is possible to trade each 1% increase in tire deflection with a circa 1% decrease in r.m.s. sprung mass acceleration. This can be used for adaptive suspension tuning based on varying road/speed conditions. The second part of this paper is concerned with the influence of unsprung mass on optimal vibration isolation for the case of a linear 2 DOF, quarter-car model. In the study, it is assumed that the tire stiffness and geometry remain the same while unsprung mass is changed. The comprehensive computer analysis shows that, for active suspensions, both ride and handling can be improved by reducing the unsprung mass. In particular, when the total vehicle mass is kept constant, every 10% reduction in unsprung mass contributes to a circa 6% reduction in r.m.s. sprung mass acceleration for the same level of wheel-hop. For active suspension vehicles, this gives an added incentive for reducing the unsprung weight through the usage of, for example, aluminum wheels and lightweight composite materials. Although used primarily in the context of automotive applications, the results of this study are generic to similar 2 DOF structures in other areas of vibration isolation, ranging from computer peripherals to off-road vehicles.

Steering redundancy for self-driving vehicles using differential braking

NASA Astrophysics Data System (ADS)

Jonasson, M.; Thor, M.

2018-05-01

This paper describes how differential braking can be used to turn a vehicle in the context of providing fail-operational control for self-driving vehicles. Two vehicle models are developed with differential input. The models are used to explain the bounds of curvature that differential braking provides and they are then validated with measurements in a test vehicle. Particular focus is paid on wheel suspension effects that significantly influence the obtained curvature. The vehicle behaviour and its limitations due to wheel suspension effects are, owing to the vehicle models, defined and explained. Finally, a model-based controller is developed to control the vehicle curvature during a fault by differential braking. The controller is designed to compensate for wheel angle disturbance that is likely to occur during the control event.

Development and Testing of a Hydropneumatic Suspension System on a USMC AAV7A1

DTIC Science & Technology

1991-07-30

original material, SAE 4140 steel alloy hardened to 30/34 Rc, has a yield strength of 130,000 psi. All of the ISU’s were disassembled and were reassembled...plugged and welded in place. Aluminum I-beams were welded in place in the water jet tunnels to act as jounce stops for the aft suspension units. The...following Is a tabulation of components attributed to the vehicle: 1000 Hull, Welded & machined 1100 Bow Plane 2000 Powertrain 3000 Transmission 4000

Influence of Flocculating Agents and Structural Vehicles on the Physical Stability and Rheological Behavior of Nitrofurantoin Suspension

PubMed Central

Moghimipour, Eskandar; Salimi, Anayatollah; Rezaee, Saeed; Balack, Maryam; Handali, Somayeh

2014-01-01

Background: Nitrofurantoin is a nitrofuran antibiotic that has been used for treatment of urinary tract against positive and negative bacteria. Objectives: The aim of this study was to evaluate the effect of structural vehicles and flocculating agents on physical stability and rheological behavior of nitrofurantoin suspension. Materials and Methods: To formulate the suspensions, the effect of glycerin and polysorbate 80 as wetting agents was evaluated and their particle sizes were determined using the sieve method. Then to achieve controlled flocculation, sodium citrate and aluminum chloride were added. After choosing the suitable wetting and flocculating agents, structural vehicles such as sodium carboxyl methyl cellulose and Veegum were evaluated individually and in combination. In addition, the effect of sorbitol on density of continuous phase and some physical stability parameters such as sedimentation volume, degree of flocculation and ease of redispersion of the suspensions were evaluated. After incorporation of structural vehicles, the rheological properties of formulations were also determined to find their flow behavior. Results: According to the results, glycerin (0.2%) and sodium citrate (0.3%) had the best effect on the suspension stability as wetting and flocculating agents, respectively. Rheological properties of formulations showed pseudoplastic behavior with some degree of thixotropy. Conclusions: In conclusion, the suspension containing Veegum 1%, sodium carboxy methyl cellulose 1%, glycerine 0.2%, sodium citrate 0.3% and sorbitol 20 % was chosen as the most physically stable formulation. PMID:24872937

The effect of spring pads in the secondary suspension of railway vehicles on bogie yaw resistance

NASA Astrophysics Data System (ADS)

Michálek, Tomáš; Zelenka, Jaromír

2015-12-01

This paper deals with properties of bogie yaw resistance of an electric locomotive with secondary suspension consisting of flexi-coil springs supplemented with tilting spring pads. Transversal stiffness of a sample of a spring/pad assembly was measured on a dynamic test stand of the University of Pardubice (Czech Republic) and the results were applied into a multi-body model of the locomotive created in the simulation tool 'SJKV'. On the basis of the simulation results, a detailed analysis of the bogie yaw resistance was performed in order to explain the effect in dynamic behaviour of the locomotive when the moment against bogie rotation (and therefore the distribution of guiding forces on individual wheels, as well) is influenced with the vehicle speed in a certain curve. Results of this analysis show that the application of suspension elements with strongly directionally dependent transversal stiffness into the secondary suspension can just lead to a dependency of the bogie yaw resistance on cant deficiency, i.e. on the vehicle speed in curve. This fact has wide consequences on the vehicle dynamics (especially on the guiding behaviour of the vehicle in curves) and it also points out that the current method of evaluation of the bogie yaw resistance according to relevant standards, which is related with assessment of the quasistatic safety of a railway vehicle against derailment, is not objective enough.

Dynamic Interaction of Long Suspension Bridges with Running Trains

NASA Astrophysics Data System (ADS)

XIA, H.; XU, Y. L.; CHAN, T. H. T.

2000-10-01

This paper presents an investigation of dynamic interaction of long suspension bridges with running trains. A three-dimensional finite element model is used to represent a long suspension bridge. Each 4-axle vehicle in a train is modelled by a 27-degrees-of-freedom dynamic system. The dynamic interaction between the bridge and train is realized through the contact forces between the wheels and track. By applying a mode superposition technique to the bridge only and taking the measured track irregularities as known quantities, the number of degrees of freedom (d.o.f.) the bridge-train system is significantly reduced and the coupled equations of motion are efficiently solved. The proposed formulation and the associated computer program are then applied to a real long suspension bridge carrying a railway within the bridge deck. The dynamic response of the bridge-train system and the derail and offload factors related to the running safety of the train are computed. The results show that the formulation presented in this paper can well predict dynamic behaviors of both bridge and train with reasonable computation efforts. Dynamic interaction between the long suspension bridge and train is not significant.

Track profile approximation using railcar body acceleration data.

DOT National Transportation Integrated Search

2014-12-01

Accelerations are frequently measured from the car body of a rail vehicle, which is mounted above one or more suspension : systems. Measuring accelerations in the car body is largely done for convenience, as mounting an accelerometer to a truck or ax...

Rheological behavior and stability of ciprofloxacin suspension: Impact of structural vehicles and flocculating agent.

PubMed

Moghimipour, Eskandar; Rezaee, Saeed; Salimi, Anayatollah; Asadi, Elham; Handali, Somayeh

2013-07-01

Ciprofloxacin is a fluoroquinolone and is used against a broad spectrum of gram-negative and gram-positive bacteria. The aim of the study is to investigate the effect of structural vehicles and other formulating factors on physical stability and rheological behavior of ciprofloxacin suspension. To formulate the suspensions, the effect of glycerin and polysorbate 80 as wetting agents was evaluated. Then to achieve controlled flocculation, different concentrations of sodium chloride and calcium chloride were added. After choosing suitable wetting and flocculating agents, structural vehicles such as sodium carboxyl methyl cellulose (NaCMC), hydroxypropylmethylcellulose (HPMC) and Veegum were evaluated. Physical stability parameters such as sedimentation volume, the degree of flocculation and the ease of redispersion of the suspensions and growth of crystals were evaluated. After incorporation of structural vehicles, the rheological properties of formulations containing were also studied to find out their rheological behavior. According to the results, suspension containing glycerin (0.2% w/v) and sodium chloride (0.05% w/v) as wetting agent and flocculating agent, respectively, were the most stable formulations regarding their F and N. Microscopic observations showed the growth of crystals in ciprofloxacin suspension in formulation without excipients and the minimum amount of crystal growth was seen in suspension containing NaCMC (0.25% w/v), Veegum (0.1% w/v) and NaCl (0.05% w/v). Rheological studies showed that almost all of the formulations had psuedoplastic behavior with different degree of thixotropy. The formulation containing NaCMC (0.25% w/v), Veegum (0.1% w/v) and NaCl (0.05% w/v) was the most stable formulation. It may be concluded that by altering the amount ratios of formulation factors, the best rheological behavior and the most proper thixotropy may be achieved.

Rheological behavior and stability of ciprofloxacin suspension: Impact of structural vehicles and flocculating agent

PubMed Central

Moghimipour, Eskandar; Rezaee, Saeed; Salimi, Anayatollah; Asadi, Elham; Handali, Somayeh

2013-01-01

Ciprofloxacin is a fluoroquinolone and is used against a broad spectrum of gram-negative and gram-positive bacteria. The aim of the study is to investigate the effect of structural vehicles and other formulating factors on physical stability and rheological behavior of ciprofloxacin suspension. To formulate the suspensions, the effect of glycerin and polysorbate 80 as wetting agents was evaluated. Then to achieve controlled flocculation, different concentrations of sodium chloride and calcium chloride were added. After choosing suitable wetting and flocculating agents, structural vehicles such as sodium carboxyl methyl cellulose (NaCMC), hydroxypropylmethylcellulose (HPMC) and Veegum were evaluated. Physical stability parameters such as sedimentation volume, the degree of flocculation and the ease of redispersion of the suspensions and growth of crystals were evaluated. After incorporation of structural vehicles, the rheological properties of formulations containing were also studied to find out their rheological behavior. According to the results, suspension containing glycerin (0.2% w/v) and sodium chloride (0.05% w/v) as wetting agent and flocculating agent, respectively, were the most stable formulations regarding their F and N. Microscopic observations showed the growth of crystals in ciprofloxacin suspension in formulation without excipients and the minimum amount of crystal growth was seen in suspension containing NaCMC (0.25% w/v), Veegum (0.1% w/v) and NaCl (0.05% w/v). Rheological studies showed that almost all of the formulations had psuedoplastic behavior with different degree of thixotropy. The formulation containing NaCMC (0.25% w/v), Veegum (0.1% w/v) and NaCl (0.05% w/v) was the most stable formulation. It may be concluded that by altering the amount ratios of formulation factors, the best rheological behavior and the most proper thixotropy may be achieved. PMID:24083201

19 CFR 112.30 - Suspension or revocation of license.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 19 Customs Duties 1 2010-04-01 2010-04-01 false Suspension or revocation of license. 112.30... Suspension or revocation of license. (a) Grounds for suspension or revocation of licenses. The port director... produced upon demand; (2) His vehicle or vessel is not properly marked, as required by § 112.27; (3) The...

Passive detection of vehicle loading

NASA Astrophysics Data System (ADS)

McKay, Troy R.; Salvaggio, Carl; Faulring, Jason W.; Salvaggio, Philip S.; McKeown, Donald M.; Garrett, Alfred J.; Coleman, David H.; Koffman, Larry D.

2012-01-01

The Digital Imaging and Remote Sensing Laboratory (DIRS) at the Rochester Institute of Technology, along with the Savannah River National Laboratory is investigating passive methods to quantify vehicle loading. The research described in this paper investigates multiple vehicle indicators including brake temperature, tire temperature, engine temperature, acceleration and deceleration rates, engine acoustics, suspension response, tire deformation and vibrational response. Our investigation into these variables includes building and implementing a sensing system for data collection as well as multiple full-scale vehicle tests. The sensing system includes; infrared video cameras, triaxial accelerometers, microphones, video cameras and thermocouples. The full scale testing includes both a medium size dump truck and a tractor-trailer truck on closed courses with loads spanning the full range of the vehicle's capacity. Statistical analysis of the collected data is used to determine the effectiveness of each of the indicators for characterizing the weight of a vehicle. The final sensing system will monitor multiple load indicators and combine the results to achieve a more accurate measurement than any of the indicators could provide alone.

Vibration mitigation for in-wheel switched reluctance motor driven electric vehicle with dynamic vibration absorbing structures

NASA Astrophysics Data System (ADS)

Qin, Yechen; He, Chenchen; Shao, Xinxin; Du, Haiping; Xiang, Changle; Dong, Mingming

2018-04-01

This paper presents a new approach for vibration mitigation based on a dynamic vibration absorbing structure (DVAS) for electric vehicles (EVs) that use in-wheel switched reluctance motors (SRMs). The proposed approach aims to alleviate the negative effects of vibration caused by the unbalanced electromagnetic force (UMEF) that arises from road excitations. The analytical model of SRMs is first formulated using Fourier series, and then a model of the coupled longitudinal-vertical dynamics is developed taking into consideration the external excitations consisting of the aerodynamic drag force and road unevenness. In addition, numerical simulations for a conventional SRM-suspension system and two novel DVASs are carried out for varying road levels specified by ISO standards and vehicle velocities. The results of the comparison reveal that a 35% improvement in ride comfort, 30% improvement of road handling, and 68% improvement in air gap between rotor and stator can be achieved by adopting the novel DVAS compared to the conventional SRM-suspension system. Finally, multi-body simulation (MBS) is performed using LMS Motion to validate the feasibility of the proposed DVAS. Analysis of the results shows that the proposed method can augment the effective application of SRMs in EVs.

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

NASA Astrophysics Data System (ADS)

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.

Vibration study of a vehicle suspension assembly with the finite element method

NASA Astrophysics Data System (ADS)

Cătălin Marinescu, Gabriel; Castravete, Ştefan-Cristian; Dumitru, Nicolae

2017-10-01

The main steps of the present work represent a methodology of analysing various vibration effects over suspension mechanical parts of a vehicle. A McPherson type suspension from an existing vehicle was created using CAD software. Using the CAD model as input, a finite element model of the suspension assembly was developed. Abaqus finite element analysis software was used to pre-process, solve, and post-process the results. Geometric nonlinearities are included in the model. Severe sources of nonlinearities such us friction and contact are also included in the model. The McPherson spring is modelled as linear spring. The analysis include several steps: preload, modal analysis, the reduction of the model to 200 generalized coordinates, a deterministic external excitation, a random excitation that comes from different types of roads. The vibration data used as an input for the simulation were previously obtained by experimental means. Mathematical expressions used for the simulation were also presented in the paper.

Temozolomide stability in extemporaneously compounded oral suspensions.

PubMed

Trissel, Lawrence A; Zhang, Yanping; Koontz, Susannah E

2006-01-01

Temozolomide, commercially available in capsules, is an oral alkylating agent used to treat brain tumors. The purpose of this study was to determine the pharmaceutical acceptability and chemical stability of temozolomide in two extemporaneously compounded suspension formulations prepared from the capsules. The temozolomide oral suspensions were prepared from 100-mg commercial capsules yielding a nominal temozolomide concentration of 10 mg/mL. The suspension vehicles selected for testing were an equal parts mixture of Ora-Plus and Ora-Sweet and an equal parts mixture of Ora-Plus and Ora-Sweet SF. The suspensions were packaged in amber plastic screw-cap prescription bottles, which were stored at 23 deg C for 21 days or 4 deg C for 60 days. Stability-indicating high-performance liquid chromatographic analysis revealed that the temozolomide concentration in both suspension vehicle combinations exhibited little or no loss for 60 days at 4 deg C. At 23 deg C, temozolomide losses were somewhat greater. In the Ora-Sweet formulation, the loss was 6% at 7 days; in the Ora-Sweet SF formulation, losses were about 8% at 14 days and 10% to 11% at 21 days. Temozolomide extemporaneously prepared as oral suspensions from capsules in equal parts mixtures of Ora-Plus suspension vehicle with Ora-Sweet and with ora-Sweet SF syrups with added povidine k-30 and acidified with citric acid were pharmaceutically acceptable and chemically stable for at least 60 days at 4 deg C. Refrigerated storage is recommended. The suspensions should not be stored at room temperature longer than 1 week if Ora-Sweet is used or longer than 2 weeks if Ora-Sweet SF is used.

Structural analysis of compression helical spring used in suspension system

NASA Astrophysics Data System (ADS)

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.

49 CFR 383.113 - Required skills.

Code of Federal Regulations, 2014 CFR

2014-10-01

... inspected to ensure a safe operating condition of each part, including: (i) Engine compartment; (ii) Cab/engine start; (iii) Steering; (iv) Suspension; (v) Brakes; (vi) Wheels; (vii) Side of vehicle; (viii... they will activate in emergency situations; (iv) With the engine running, make sure that the system...

49 CFR 383.113 - Required skills.

Code of Federal Regulations, 2012 CFR

2012-10-01

... inspected to ensure a safe operating condition of each part, including: (i) Engine compartment; (ii) Cab/engine start; (iii) Steering; (iv) Suspension; (v) Brakes; (vi) Wheels; (vii) Side of vehicle; (viii... they will activate in emergency situations; (iv) With the engine running, make sure that the system...

49 CFR 383.113 - Required skills.

Code of Federal Regulations, 2013 CFR

2013-10-01

... inspected to ensure a safe operating condition of each part, including: (i) Engine compartment; (ii) Cab/engine start; (iii) Steering; (iv) Suspension; (v) Brakes; (vi) Wheels; (vii) Side of vehicle; (viii... they will activate in emergency situations; (iv) With the engine running, make sure that the system...

49 CFR 383.113 - Required skills.

Code of Federal Regulations, 2011 CFR

2011-10-01

... inspected to ensure a safe operating condition of each part, including: (i) Engine compartment; (ii) Cab/engine start; (iii) Steering; (iv) Suspension; (v) Brakes; (vi) Wheels; (vii) Side of vehicle; (viii... they will activate in emergency situations; (iv) With the engine running, make sure that the system...

Stability of nonaqueous suspension formulations of plasma derived factor IX and recombinant human alpha interferon at elevated temperatures.

PubMed

Knepp, V M; Muchnik, A; Oldmark, S; Kalashnikova, L

1998-07-01

To identify a suitable nonaqueous, parenterally acceptable suspending vehicle whereby a therapeutic protein is delivered as a stable flowable powder, making it amenable to delivery from sustained delivery systems maintained at body temperature. Formulations of plasma derived Factor IX (pdFIX) and recombinant human alpha interferon (rhalpha-IFN) were formulated as dry powders, suspended in various vehicles (perfluorodecalin, perfluorotributylamine, methoxyflurane, polyethylene glycol 400, soybean oil, tetradecane or octanol) and stored at 37 degrees C. Stability was assessed by size exclusion chromatography, reverse phase chromatography, ion exchange chromatography, and bioassay, and was compared to the stability of dry powder formulations stored at 37 degrees C and -80 degrees C. PdFIX was stable when stored at 37 degrees C as a dry powder, or when the dry powder was suspended in the pharmaceutically acceptable vehicles perfluorodecalin or perfluorotributylamine. Suspensions of the powder in other pharmaceutically/parenterally acceptable vehicles such as soybean oil or PEG 400 resulted in aggregation and loss of bioactivity. A dry powder formulation of rhalpha-IFN suspended in perfluorodecalin was also stable at 37 degrees C. This study shows the potential utility of perfluorinated hydrocarbons as nonaqueous suspending vehicles for long term in-vivo delivery of therapeutic proteins.

Lunar articulated remote transportation system

NASA Technical Reports Server (NTRS)

Beech, Geoffrey; Conley, Gerald; Diaz, Claudine; Dimella, Timothy; Dodson, Pete; Hykin, Jeff; Richards, Byron; Richardson, Kroy; Shetzer, Christie; Vandyke, Melissa

1990-01-01

A first generation lunar transportation vehicle was designed for use on the surface of the Moon between the years 2010 and 2020. Attention is focussed on specific design details on all components of the Lunar Articulated Remote Transportation System (Lunar ARTS). The Lunar ARTS will be a three cart, six-wheeled articulated vehicle. It's purpose will be for the transportation of astronauts and/or materials for excavation purposes at a short distance from the base (37.5 kilometers). The power system includes fuel cells for both the primary system and the back-up system. The vehicle has the option of being operated in a manned or unmanned mode. The unmanned mode includes stereo imaging with signal processing for navigation. For manned missions the display console is a digital readout displayed on the inside of the asronaut's helmet. A microprocessor is also on board the vehicle. Other components of the vehicle include: a double wishbone/flexible hemispherical wheel suspension; chassis; a steering system; motors; seat restraints, heat rejection systems; solar flare protection; dust protection; and meteoroid protection. A one-quarter scale dynamic model was built to study the dynamic behavior of the vehicle. The dynamic model closely captures the mechanical and electrical details of the total design.

Torsion bar stabilizer for a vehicle and method for mounting the stabilizer on the vehicle frame

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sauber, C.J.

This patent describes a method of mounting a stabilizing mechanism on a vehicle frame which is supported and biased on a suspension assembly at opposite sides of the frame. The frame includes overload stops riveted to opposite sides of the frame and the suspension assembly includes bracket assemblies which secure the vehicle's suspension springs to a wheel axle. The method comprises the following steps: removing an overload stop from each side of the vehicle frame; mounting a modified overload stop on each side of the frame which serves as both an overload stop and a support for the stabilizing mechanismmore » wherein the modified overload stop is mounted into the holes in the frame left from the removal of the overload stop; removing from each side of the vehicle the top bracket from the bracket assembly; inserting a modified top bracket into each bracket assembly wherein the top bracket assembly is modified to couple with the stabilizing mechanism; and mounting on the modified overload stops a torsion bar whose opposite ends are coupled to the modified top bracket by way of linkages.« less

A LQR-Based Controller with Estimation of Road Bank for Improving Vehicle Lateral and Rollover Stability via Active Suspension

PubMed Central

Sanz, Susana

2017-01-01

In this article, a Linear Quadratic Regulator (LQR) lateral stability and rollover controller has been developed including as the main novelty taking into account the road bank angle and using exclusively active suspension for both lateral stability and rollover control. The main problem regarding the road bank is that it cannot be measured by means of on-board sensors. The solution proposed in this article is performing an estimation of this variable using a Kalman filter. In this way, it is possible to distinguish between the road disturbance component and the vehicle’s roll angle. The controller’s effectiveness has been tested by means of simulations carried out in TruckSim, using an experimentally-validated vehicle model. Lateral load transfer, roll angle, yaw rate and sideslip angle have been analyzed in order to quantify the improvements achieved on the behavior of the vehicle. For that purpose, these variables have been compared with the results obtained from both a vehicle that uses passive suspension and a vehicle using a fuzzy logic controller. PMID:29027910

Feasibility Study for Implementing Magnetic Suspension in the Glenn Research Center 225 cm2 Supersonic Wind Tunnel for Testing the Dynamic Stability of Blunt Bodies

NASA Technical Reports Server (NTRS)

Sevier, Abigail; Davis, David O.; Schoenenberger, Mark; Barnhart, Paul

2016-01-01

The implementation of a magnetic suspension system in the NASA Glenn Research Center (GRC) 225 cm2 Supersonic Wind Tunnel would be a powerful test technique that could accurately determine the dynamic stability of blunt body entry vehicles with no sting interference. This paper explores initial design challenges to be evaluated before implementation, including defining the lowest possible operating dynamic pressure and corresponding model size, developing a compatible video analysis technique, and incorporating a retractable initial support sting.

Design of a recovery system for a reentry vehicle

NASA Technical Reports Server (NTRS)

Von Eckroth, Wulf; Garrard, William L.; Miller, Norman

1993-01-01

Engineers are often required to design decelerator systems which are deployed in cross-wind orientations. If the system is not designed to minimize 'line sail', damage to the parachutes could result. A Reentry Vehicle Analysis Code (RVAC) and an accompanying graphics animation software program (DISPLAY) are presented in this paper. These computer codes allow the user to quickly apply the Purvis line sail modeling technique to any vehicle and then observe the relative motion of the vehicle, nose cap, suspension lines, pilot and drogue bags and canopies on a computer screen. Data files are created which allow plots of velocities, spacial positions, and dynamic pressures versus time to be generated. The code is an important tool for the design engineer because it integrates two degrees of freedom (DOF) line sail equations with a three DOF model of the reentry body and jettisoned nose cap to provide an animated output.

Virtual test rig to improve the design and optimisation process of the vehicle steering and suspension systems

NASA Astrophysics Data System (ADS)

Mántaras, Daniel A.; Luque, Pablo

2012-10-01

A virtual test rig is presented using a three-dimensional model of the elasto-kinematic behaviour of a vehicle. A general approach is put forward to determine the three-dimensional position of the body and the main parameters which influence the handling of the vehicle. For the design process, the variable input data are the longitudinal and lateral acceleration and the curve radius, which are defined by the user as a design goal. For the optimisation process, once the vehicle has been built, the variable input data are the travel of the four struts and the steering wheel angle, which is obtained through monitoring the vehicle. The virtual test rig has been applied to a standard vehicle and the validity of the results has been proven.

Superconducting Electromagnetic Suspension (EMS) system for Grumman Maglev concept

NASA Technical Reports Server (NTRS)

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.

Optimisation of active suspension control inputs for improved vehicle handling performance

NASA Astrophysics Data System (ADS)

Čorić, Mirko; Deur, Joško; Kasać, Josip; Tseng, H. Eric; Hrovat, Davor

2016-11-01

Active suspension is commonly considered under the framework of vertical vehicle dynamics control aimed at improvements in ride comfort. This paper uses a collocation-type control variable optimisation tool to investigate to which extent the fully active suspension (FAS) application can be broaden to the task of vehicle handling/cornering control. The optimisation approach is firstly applied to solely FAS actuator configurations and three types of double lane-change manoeuvres. The obtained optimisation results are used to gain insights into different control mechanisms that are used by FAS to improve the handling performance in terms of path following error reduction. For the same manoeuvres the FAS performance is compared with the performance of different active steering and active differential actuators. The optimisation study is finally extended to combined FAS and active front- and/or rear-steering configurations to investigate if they can use their complementary control authorities (over the vertical and lateral vehicle dynamics, respectively) to further improve the handling performance.

49 CFR 393.201 - Frames.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 5 2010-10-01 2010-10-01 false Frames. 393.201 Section 393.201 Transportation... SAFE OPERATION Frames, Cab and Body Components, Wheels, Steering, and Suspension Systems § 393.201 Frames. (a) The frame or chassis of each commercial motor vehicle shall not be cracked, loose, sagging or...

Calcipotriene plus betamethasone dipropionate topical suspension for the treatment of mild to moderate psoriasis vulgaris on the body: a randomized, double-blind, vehicle-controlled trial.

PubMed

Menter, Alan; Gold, Linda Stein; Bukhalo, Michael; Grekin, Steven; Kempers, Steven; Boyce, Brent M; Ganslandt, Cecilia; Villumsen, John; Lebwohl, Mark

2013-01-01

A combination topical suspension/gel containing calcipotriene plus betamethasone dipropionate has been developed as a safe and effective treatment for patients with psoriasis vulgaris of the scalp. This same preparation has the potential to be a convenient, effective, and cosmetically appealing formulation for psoriasis on the body. This trial evaluated the efficacy and safety of a topical suspension containing calcipotriene plus betamethasone dipropionate compared with its constituent components and topical suspension vehicle in the treatment of mild to moderate psoriasis on the trunk and limbs. This was a randomized, double-blind, vehicle-controlled, 4-arm trial in 1,152 subjects. The co-primary efficacy end points were the proportion of subjects achieving controlled disease based on the Investigators' Global Assessment of disease severity at weeks 4 and 8. Adverse events, vital signs, and clinical laboratory measurements were also assessed. At week 4, a greater proportion of subjects in the calcipotriene plus betamethasone group achieved controlled disease compared with subjects in the calcipotriene-only and vehicle-only treatment groups. At week 8, a statistically significantly (P<.01) greater proportion of subjects in the calcipotriene plus betamethasone group achieved controlled disease compared with subjects in the 3 other treatment groups. Adverse events and other safety assessments were similar between the groups. The topical suspension containing calcipotriene plus betamethasone dipropionate traditionally used for scalp psoriasis is also a safe and effective once-daily treatment for psoriasis vulgaris on the body.

Preparation and enhancement of oral bioavailability of curcumin using microemulsions vehicle.

PubMed

Hu, Liandong; Jia, Yanhong; Niu, Feng; Jia, Zheng; Yang, Xun; Jiao, Kuiliang

2012-07-25

A new microemulsions system of curcumin (CUR-MEs) was successfully developed to improve the solubility and bioavailability of curcumin. Several formulations of the microemulsions system were prepared and evaluated using different ratios of oils, surfactants, and co-surfactants (S&CoS). The optimal formulation, which consists of Capryol 90 (oil), Cremophor RH40 (surfactant), and Transcutol P aqueous solution (co-surfactant), could enhance the solubility of curcumin up to 32.5 mg/mL. The pharmacokinetic study of microemulsions was performed in rats compared to the corresponding suspension. The stability of microemulsions after dilution was excellence. Microemulsions have significantly increased the C(max) and area under the curve (AUC) in comparison to that in suspension (p < 0.05). The relative bioavailability of curcumin in microemulsions was 22.6-fold higher than that in suspension. The results indicated that the CUR-MEs could be used as an effective formulation for enhancing the oral bioavailability of curcumin.

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

NASA Astrophysics Data System (ADS)

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.

49 CFR 383.33 - Notification of driver's license suspensions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 5 2010-10-01 2010-10-01 false Notification of driver's license suspensions. 383... Employer Responsibilities § 383.33 Notification of driver's license suspensions. Each employee who has a... operate a commercial motor vehicle in a State or jurisdiction for any period, or who is disqualified from...

Simulation analysis of the EUSAMA Plus suspension testing method including the impact of the vehicle untested side

NASA Astrophysics Data System (ADS)

Dobaj, K.

2016-09-01

The work deals with the simulation analysis of the half car vehicle model parameters on the suspension testing results. The Matlab simulation software was used. The considered model parameters are involved with the shock absorber damping coefficient, the tire radial stiffness, the car width and the rocker arm length. The consistent vibrations of both test plates were considered. Both wheels of the car were subjected to identical vibration, with frequency changed similar to the EUSAMA Plus principle. The shock absorber damping coefficient (for several values of the car width and rocker arm length) was changed on one and both sides of the vehicle. The obtained results are essential for the new suspension testing algorithm (basing on the EUSAMA Plus principle), which will be the aim of the further author's work.

Synthesis of the adaptive continuous system for the multi-axle wheeled vehicle body oscillation damping

NASA Astrophysics Data System (ADS)

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

2018-02-01

In order to meet the growing mobility requirements for the wheeled vehicles on all types of terrain the engineers have to develop a large number of specialized control algorithms for the multi-axle wheeled vehicle (MWV) suspension improving such qualities as ride comfort, handling and stability. The authors have developed an adaptive algorithm of the dynamic damping of the MVW body oscillations. The algorithm provides high ride comfort and high mobility of the vehicle. The article discloses a method for synthesis of an adaptive dynamic continuous algorithm of the MVW body oscillation damping and provides simulation results proving high efficiency of the developed control algorithm.

A technical feasibility study of surfactant-free drug suspensions using octenyl succinate-modified starches.

PubMed

Kuentz, Martin; Egloff, Peter; Röthlisberger, Dieter

2006-05-01

Many new drugs exhibit poor wetting behaviour and low aqueous solubility. This is particularly an issue for preclinical studies like toxicological trials, in which considerably higher doses and volumes are being administered compared to clinical studies. Preclinical vehicles typically contain high levels of surfactants that can exert biological effects. However, the biological inertness of vehicles is pivotal for the application in preclinical studies stressing the need in finding new excipients to solve formulation problems of today's drug discovery. The present study investigated the technical feasibility of surfactant-free suspensions using a new poorly soluble drug as model. It was shown that octenyl succinate-modified starches adequately wetted the drug and homogenous tasteless suspensions were obtained. The polymer xanthan gum was identified as macroscopically compatible gelling agent. Concentration effects of xanthan, drug and different modified starches were studied in a D-optimal design with respect to rheological properties. The suspensions were also tested in an analytical centrifuge using NIR transmission profiles to obtain a measure of sedimentation stability under accelerated conditions. The modified starches exhibited only little influence on the viscosity as well as on the yield point in contrast to the rheological effects of xanthan gum. This gelling agent was the main stabilising excipient as the modified starches hindered to a lesser extent sedimentation. The most stable suspensions displayed convenient flow properties. The viscosity at 100 s(-1) and 25 degrees C was in technically acceptable range of 120-140 mPa s in view of a application via gavage or a syringe in animal studies. The results demonstrated that surfactant-free drug suspensions with excellent technical performance can be obtained using octenyl succinate-modified starches. The vehicles were tasteless and based on the experience of modified starches in the food industry, the vehicles should exhibit good tolerability. The future use of such surfactant-free drug suspensions in toxicological, pharmacokinetic and pharmacodynamic studies will have to determine their advantage in terms of biological inertness.

Integrated thermal management of a hybrid electric vehicle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Traci, R.M.; Acebal, R.; Mohler, T.

1999-01-01

A thermal management methodology, based on the Vehicle Integrated Thermal Management Analysis Code (VITMAC), has been developed for a notional vehicle employing the All-Electric Combat Vehicle (AECV) concept. AECV uses a prime power source, such as a diesel, to provide mechanical energy which is converted to electrical energy and stored in a central energy storage system consisting of flywheels, batteries and/or capacitors. The combination of prime power and stored energy powers the vehicle drive system and also advanced weapons subsystems such as an ETC or EM gun, electrically driven lasers, an EM armor system and an active suspension. Every majormore » system is electrically driven with energy reclamation when possible from braking and gun recoil. Thermal management of such a complicated energy transfer and utilization system is a major design consideration due to the substantial heat rejection requirements. In the present paper, an overall integrated thermal management system (TMS) is described which accounts for energy losses from each subsystem component, accepts the heat using multiple coolant loops and expels the heat from the vehicle. VITMAC simulations are used to design the TMS and to demonstrate that a conventional TMS approach is capable of successfully handling vehicle heat rejection requirements under stressing operational conditions.« less

Stability and optimised H∞ control of tripped and untripped vehicle rollover

NASA Astrophysics Data System (ADS)

Jin, Zhilin; Zhang, Lei; Zhang, Jiale; Khajepour, Amir

2016-10-01

Vehicle rollover is a serious traffic accident. In order to accurately evaluate the possibility of untripped and some special tripped vehicle rollovers, and to prevent vehicle rollover under unpredictable variations of parameters and harsh driving conditions, a new rollover index and an anti-roll control strategy are proposed in this paper. Taking deflections of steering and suspension induced by the roll at the axles into consideration, a six degrees of freedom dynamic model is established, including lateral, yaw, roll, and vertical motions of sprung and unsprung masses. From the vehicle dynamics theory, a new rollover index is developed to predict vehicle rollover risk under both untripped and special tripped situations. This new rollover index is validated by Carsim simulations. In addition, an H-infinity controller with electro hydraulic brake system is optimised by genetic algorithm to improve the anti-rollover performance of the vehicle. The stability and robustness of the active rollover prevention control system are analysed by some numerical simulations. The results show that the control system can improve the critical speed of vehicle rollover obviously, and has a good robustness for variations in the number of passengers and longitude position of the centre of gravity.

The first man-loading high temperature superconducting Maglev test vehicle in the world

NASA Astrophysics Data System (ADS)

Wang, Jiasu; Wang, Suyu; Zeng, Youwen; Huang, Haiyu; Luo, Fang; Xu, Zhipei; Tang, Qixue; Lin, Guobin; Zhang, Cuifang; Ren, Zhongyou; Zhao, Guomin; Zhu, Degui; Wang, Shaohua; Jiang, He; Zhu, Min; Deng, Changyan; Hu, Pengfei; Li, Chaoyong; Liu, Fang; Lian, Jisan; Wang, Xiaorong; Wang, Lianghui; Shen, Xuming; Dong, Xiaogang

2002-10-01

The first man-loading high temperature superconducting Maglev test vehicle in the world is reported. This vehicle was first tested successfully on December 31, 2000 in the Applied Superconductivity Laboratory, Southwest Jiaotong University, China. Heretofore over 17,000 passengers took the vehicle, and it operates very well from beginning to now. The function of suspension is separated from one of propulsion. The high temperature superconducting Maglev provides inherent stable forces both in the levitation and in the guidance direction. The vehicle is 3.5 m long, 1.2 m wide, and 0.8 m high. When five people stand on vehicle and the total weight is 530 kg, the net levitation gap is more than 20 mm. The whole vehicle system includes three parts, vehicle body, guideway and controlling system. The high temperature superconducting Maglev equipment on board is the most important for the system. The onboard superconductors are melt-textured YBaCuO bulks. The superconductors are fixed on the bottom of liquid nitrogen vessels and cooled by liquid nitrogen. The guideway consists of two parallel permanent magnetic tracks, whose surface concentrating magnetic field is up to 1.2 T. The guideway is 15.5 m long.

Stability of three commonly compounded extemporaneous enrofloxacin suspensions for oral administration to exotic animals.

PubMed

Petritz, Olivia A; Guzman, David Sanchez-Migallon; Wiebe, Valerie J; Papich, Mark G

2013-07-01

To evaluate the stability of 3 extemporaneous oral suspensions of enrofloxacin mixed with readily available flavoring vehicles when stored at room temperature (approx 22°C). Evaluation study. 3 commonly compounded oral suspensions of enrofloxacin. On day 0, commercially available enrofloxacin tablets were compounded with a mixture of distilled water and corn syrup (formulation A) or cherry syrup (formulation B) flavoring vehicles to create suspensions with a nominal enrofloxacin concentration of 22.95 mg/mL, and 2.27% enrofloxacin injectable solution was compounded with a liquid sweetener (formulation C) to create a suspension with a nominal enrofloxacin concentration of 11.35 mg/mL. Preparations were stored in amber-colored vials at room temperature for 56 days. For each preparation, the enrofloxacin concentration was evaluated with high-performance liquid chromatography at prespecified intervals during the study. The pH, odor, and consistency for all suspensions were recorded at the start and completion of the study. Relative to the nominal enrofloxacin concentration, the enrofloxacin concentration strength ranged from 95.80% to 100.69% for formulation A, 108.44% to 111.06% for formulation B, and 100.99% to 103.28% for formulation C. A mild pH increase was detected in all 3 suspensions during the study. Results indicated that, when stored in amber-colored vials at room temperature for 56 days, the enrofloxacin concentration strength in all 3 formulations was retained within acceptance criteria of 90% to 110%. Subjectively, cherry syrup flavoring was better at masking the smell and taste of enrofloxacin than were the other mixing vehicles.

Payload isolation and stabilization by a Suspended Experiment Mount (SEM)

NASA Technical Reports Server (NTRS)

Bailey, Wayne L.; Desanctis, Carmine E.; Nicaise, Placide D.; Schultz, David N.

1992-01-01

Many Space Shuttle and Space Station payloads can benefit from isolation from crew or attitude control system disturbances. Preliminary studies have been performed for a Suspended Experiment Mount (SEM) system that will provide isolation from accelerations and stabilize the viewing direction of a payload. The concept consists of a flexible suspension system and payload-mounted control moment gyros. The suspension system, which is rigidly locked for ascent and descent, isolates the payload from high frequency disturbances. The control moment gyros stabilize the payload orientation. The SEM will be useful for payloads that require a lower-g environment than a manned vehicle can provide, such as materials processing, and for payloads that require stabilization of pointing direction, but not large angle slewing, such as nadir-viewing earth observation or solar viewing payloads.

Descriptive analysis of combine cabin vibrations and their effect on the human body

NASA Astrophysics Data System (ADS)

Hostens, I.; Ramon, H.

2003-09-01

All on- and off-road vehicles are exposed to vibrations caused by unevenness of road or soil profile, moving elements within the machine or implements. A higher prevalence of low back pain is found in drivers of off-road machinery than in other drivers. In this study, significantly higher levels of low-frequency vibrations are found in the cabin of a combine, driving at high speed (20 km/h) on a concrete surface, compared to driving slower on field road. Comfort values indicate that injury can result from long-term driving on the field as well as on a concrete road. As seats with suspension systems are the main transmission paths of vibration towards the spine of the driver, their vibration attenuating characteristics play an important role in comfort assessment. The resonant frequency of seats with passive suspension system, used in agricultural machinery, lies in the low-frequency range most excited in agricultural machinery. A seat with air suspension is found to attenuate better frequencies above 4 Hz and provide more comfort to the driver than a seat with a mechanical suspension.

32 CFR 636.3 - Suspension or revocation of driving privileges.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 4 2010-07-01 2010-07-01 true Suspension or revocation of driving privileges. 636.3 Section 636.3 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) LAW ENFORCEMENT AND CRIMINAL INVESTIGATIONS MOTOR VEHICLE TRAFFIC SUPERVISION (SPECIFIC INSTALLATIONS) Fort Stewart, Georgia § 636.3 Suspension...

Stability of extemporaneous pediatric oral liquids compounded from tablets and drug substance: case of propranolol and theophylline.

PubMed

Muśko, Monika; Sznitowska, Małgorzata

2013-01-01

The stability of theophylline (T) and propranolol hydrochloride (P) in extemporaneously compounded oral suspensions (25 mg/mL or 50 mg/mL for T and 2 mg/mL or 5 mg/mL for P) were studied. Suspension with P and T were prepared with bulk substance or tablets using three different suspending vehicles: Ora-Sweet (M1), modified Ora-Sweet (M2) and simple syrup with glycerol and sorbitol (M3). Each suspension was stored for 35 days in a dark place at 25 degrees C and 4 degrees C. The results demonstrated that the prepared suspensions with P either from tablets or from a substance were stable in all three studied vehicles (more than 95% of initial concentration remaining). However, it is recommended that storage at 4 degrees C of suspensions prepared with M2 should be avoided because of crystallization of the buffer substances. Extemporaneous suspensions with T in an appropriate pediatric concentrations of the drug were not obtained because the problem of fast crystallization of T was not eliminated.

Lunar articulated remote transportation system

NASA Technical Reports Server (NTRS)

1990-01-01

The students of the Florida A&M/Florida State University College of Engineering continued their design from 1988 to 1989 on a first generation lunar transportation vehicle for use on the surface of the Moon between the years 2010 and 2020. Attention is focused on specific design details on all components of the Lunar Articulated Remote Transportation System (Lunar ARTS). The Lunar ARTS will be a three-cart, six-wheeled articulated vehicle. Its purpose will be the transportation of astronauts and/or materials for excavation purposes at a short distance from the base (37.5 km). The power system includes fuel cells for both the primary system and the back-up system. The vehicle has the option of being operated in a manned or unmanned mode. The unmanned mode includes stereo imaging with signal processing for navigation. For manned missions the display console is a digital readout displayed on the inside of the astronaut's helmet. A microprocessor is also on board the vehicle. Other components of the vehicle include a double wishbone/flexible hemispherical wheel suspension; chassis; a steering system; motors; seat retraints; heat rejection systems; solar flare protection; dust protection; and meteoroid protection. A one-quarter scale dynamic model has been built to study the dynamic behavior of the vehicle. The dynamic model closely captures the mechanical and electrical details of the total design.

Vehicle lift-off modelling and a new rollover detection criterion

NASA Astrophysics Data System (ADS)

Mashadi, Behrooz; Mostaghimi, Hamid

2017-05-01

The modelling and development of a general criterion for the prediction of rollover threshold is the main purpose of this work. Vehicle dynamics models after the wheels lift-off and when the vehicle moves on the two wheels are derived and the governing equations are used to develop the rollover threshold. These models include the properties of the suspension and steering systems. In order to study the stability of motion, the steady-state solutions of the equations of motion are carried out. Based on the stability analyses, a new relation is obtained for the rollover threshold in terms of measurable response parameters. The presented criterion predicts the best time for the prevention of the vehicle rollover by applying a correcting moment. It is shown that the introduced threshold of vehicle rollover is a proper state of vehicle motion that is best for stabilising the vehicle with a low energy requirement.

49 CFR 107.502 - General registration requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... one or more tanks or cargo tanks on a motor vehicle or to a motor vehicle suspension component; (ii... MATERIALS PROGRAM PROCEDURES Registration of Cargo Tank and Cargo Tank Motor Vehicle Manufacturers... the certification of the cargo tank motor vehicle; or (iii) The installation of linings, coatings, or...

Dry powder dosing in liquid vehicles: ocular tolerance and scintigraphic evaluation of a perfluorocarbon suspension.

PubMed

Zhu, Y; Wilson, C G; Meadows, D; Olejnik, O; Frier, M; Washington, N; Musson, R

1999-11-30

The ocular tolerance and precorneal disposition of 99mTc-labelled sterile carbon-perfluorodecalin (PFD) and carbon-aqueous suspensions were examined in a cohort of healthy volunteers. Formulations were prepared in PFD or saline using charcoal particles, radiolabelled with [99mTc]diethylenetriaminepentaacetic acid (DTPA) under GMP conditions. Colloidal silicon dioxide was used as a suspending agent. Ocular tolerance was examined following the instillation of each formulation to the eyes of 12 volunteers. The precorneal distribution of both formulations in man was monitored using gamma scintigraphy. Dynamic and static data acquisitions were taken over a period of 150 min after dosing. Carbon particulates suspended in PFD did not show any irritation to the eye. Administration of PFD formulation in man produced a significant increase in ocular retention over a saline formulation (mean residence time (MRT)=157+/-42 and 0.29+/-0.08 min, respectively, P=0.0001). Distribution of the carbon in man followed the same pattern as in a previous reported study in animals. The carbon deposited uniformly along the lid margin in the case of the PFD vehicle, whereas it agglomerated following dosing in the saline vehicle and was ejected from the eye. The novel non-aqueous vehicle system is able to significantly improve the ocular retention of charcoal particles in man and provides a unique distribution of the particles in the eye, which suggests a potential for the PFD system for the treatment of periocular diseases.

Analysis of Rail Transit Vehicle Dynamic Curving Performance

DOT National Transportation Integrated Search

1984-06-01

An analytical model is developed for determining the dynamic curving performance of rail transit vehicles. The dynamic wheel/rail interaction forces, vehicle suspension and body motions and track displacement are computed, as well as wheel and rail w...

The Shock and Vibration Digest, Volume 18, Number 2

DTIC Science & Technology

1986-02-01

Bounce Response of Canadian 71. McMunn, J.C., "Multi-Parameter Optimum MAGLEV Vehicle under Guideway Excitation. . Damping in Linear Dynamical Systems...Northeast Corridor High-Speed Test Cars," J. "Suspension Bounce Response of Canadian L’,-*’-.-" Engrg. Indus., Trans. ASME, 91B (3), pp 897-907 MAGLEV

Chassis integrated control for active suspension, active front steering and direct yaw moment systems using hierarchical strategy

NASA Astrophysics Data System (ADS)

Zhao, Jing; Wong, Pak Kin; Ma, Xinbo; Xie, Zhengchao

2017-01-01

This paper proposes a novel integrated controller with three-layer hierarchical structure to coordinate the interactions among active suspension system (ASS), active front steering (AFS) and direct yaw moment control (DYC). First of all, a 14-degree-of-freedom nonlinear vehicle dynamic model is constructed. Then, an upper layer is designed to calculate the total corrected moment for ASS and intermediate layer based on linear moment distribution. By considering the working regions of the AFS and DYC, the intermediate layer is functionalised to determine the trigger signal for the lower layer with corresponding weights. The lower layer is utilised to separately trace the desired value of each local controller and achieve the local control objectives of each subsystem. Simulation results show that the proposed three-layer hierarchical structure is effective in handling the working region of the AFS and DYC, while the quasi-experimental result shows that the proposed integrated controller is able to improve the lateral and vertical dynamics of the vehicle effectively as compared with a conventional electronic stability controller.

32 CFR 634.9 - Suspension or revocation of driving or privately owned vehicle registration privileges.

Code of Federal Regulations, 2012 CFR

2012-07-01

... owned vehicle registration privileges. 634.9 Section 634.9 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) LAW ENFORCEMENT AND CRIMINAL INVESTIGATIONS MOTOR VEHICLE... vehicle registration privileges. The installation commander or designee may for cause, or any lawful...

32 CFR 634.9 - Suspension or revocation of driving or privately owned vehicle registration privileges.

Code of Federal Regulations, 2013 CFR

2013-07-01

... owned vehicle registration privileges. 634.9 Section 634.9 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) LAW ENFORCEMENT AND CRIMINAL INVESTIGATIONS MOTOR VEHICLE... vehicle registration privileges. The installation commander or designee may for cause, or any lawful...

32 CFR 634.9 - Suspension or revocation of driving or privately owned vehicle registration privileges.

Code of Federal Regulations, 2014 CFR

2014-07-01

... owned vehicle registration privileges. 634.9 Section 634.9 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) LAW ENFORCEMENT AND CRIMINAL INVESTIGATIONS MOTOR VEHICLE... vehicle registration privileges. The installation commander or designee may for cause, or any lawful...

32 CFR 634.9 - Suspension or revocation of driving or privately owned vehicle registration privileges.

Code of Federal Regulations, 2011 CFR

2011-07-01

... owned vehicle registration privileges. 634.9 Section 634.9 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) LAW ENFORCEMENT AND CRIMINAL INVESTIGATIONS MOTOR VEHICLE... vehicle registration privileges. The installation commander or designee may for cause, or any lawful...

Real-time identification of vehicle motion-modes using neural networks

NASA Astrophysics Data System (ADS)

Wang, Lifu; Zhang, Nong; Du, Haiping

2015-01-01

A four-wheel ground vehicle has three body-dominated motion-modes, that is, bounce, roll, and pitch motion-modes. Real-time identification of these motion-modes can make vehicle suspensions, in particular, active suspensions, target on the dominant motion-mode and apply appropriate control strategies to improve its performance with less power consumption. Recently, a motion-mode energy method (MEM) was developed to identify the vehicle body motion-modes. However, this method requires the measurement of full vehicle states and road inputs, which are not always available in practice. This paper proposes an alternative approach to identify vehicle primary motion-modes with acceptable accuracy by employing neural networks (NNs). The effectiveness of the trained NNs is verified on a 10-DOF full-car model under various types of excitation inputs. The results confirm that the proposed method is effective in determining vehicle primary motion-modes with comparable accuracy to the MEM method. Experimental data is further used to validate the proposed method.

An analytical study of electric vehicle handling dynamics

NASA Technical Reports Server (NTRS)

Greene, J. E.; Segal, D. J.

1979-01-01

Hypothetical electric vehicle configurations were studied by applying available analytical methods. Elementary linearized models were used in addition to a highly sophisticated vehicle dynamics computer simulation technique. Physical properties of specific EV's were defined for various battery and powertrain packaging approaches applied to a range of weight distribution and inertial properties which characterize a generic class of EV's. Computer simulations of structured maneuvers were performed for predicting handling qualities in the normal driving range and during various extreme conditions related to accident avoidance. Results indicate that an EV with forward weight bias will possess handling qualities superior to a comparable EV that is rear-heavy or equally balanced. The importance of properly matching tires, suspension systems, and brake system front/rear torque proportioning to a given EV configuration during the design stage is demonstrated.

Ancient road transport devices: Developments from the Bronze Age to the Roman Empire

NASA Astrophysics Data System (ADS)

Rossi, Cesare; Chondros, Thomas G.; Milidonis, Kypros F.; Savino, Sergio; Russo, Flavio

2016-03-01

The development of transportation systems has significantly enhanced the welfare and modernization of society. Wooden vehicles pulled by animals have been used for land transportation since the early Bronze Age. Whole-body gharries with rigid wheels pulled by oxen appeared in Crete by 2000 BC or earlier. Horses originating from the East were depicted in early Cretan seal-rings of the same period. The two-wheeled horsedrawn chariot was one of the most important inventions in history. This vehicle provided humanity its first concept of personal transport and was the key technology of war for 2000 years. Chariots of Mycenaean and Archaic Greece with light and flexible four-spoked wheels acting as spring suspensions were depicted in vase paintings. The development of this vehicle incorporated the seeds of a primitive design activity and was important for engineering. The Trojan horse since 1194 BC and the helepolis since 700 BC were the first known machines on a wheeled base transported by horses or self-powered. Ancient engineers invented bearings lubricated with fat, and Romans introduced the ancestors of ball bearings for their wagons and carts. The historic evolution of wheeled transportation systems, along with early traction, suspension, and braking systems, is presented in this paper. Analytical and numerical methods are incorporated to analyze the most conceivable loading situations of typically reconstructed wheeled transportation systems in ancient times. Traction requirements both for horse-driven machines and the power for internal motors are also analyzed. This study can serve as a basis for further development of detailed reconstruction of transportation systems in antiquity.

Stability of Alprazolam, Atropine Sulfate, Glutamine, Levofloxacin, Metoprolol Tartrate, Nitrofurantoin, Ondansetron Hydrochloride, Oxandrolone, Pregabaline, and Riboflavin in SyrSpend SF pH4 Oral Suspensions.

PubMed

Ferreira, Anderson O; Polonini, Hudson C; Loures da Silva, Sharlene; Cerqueira de Melo, Victor Augusto; de Andrade, Laura; Brandão, Marcos Antônio Fernandes

2017-01-01

The objective of this study was to evaluate the stability of 10 commonly used active pharmaceutical ingredients compounded in oral suspensions using an internationally used suspending vehicle (SyrSpend SF PH4): alprazolam 1.0 mg/mL, atropine sulfate 0.1 mg/mL, glutamine 250.0 mg/mL, levofloxacin 50.0 mg/mL, metoprolol tartrate 10.0 mg/mL, nitrofurantoin 2.0 mg/mL, ondansetron hydrochloride 0.8 mg/mL, oxandrolone 3.0 mg/mL, pregabaline 20.0 mg/mL, riboflavin 10.0 mg/mL. All suspensions were stored at both controlled refrigeration (2°C to 8°C) and controlled room temperature (20°C to 25°C). Stability was assessed by measuring the percent recovery at varying time points throughout a 90-day period. Active pharmaceutical ingredients quantification was performed by high-performance liquid chromatography via a stability-indicating method. Given the percentage of recovery of the active pharmaceutical ingredients within the suspensions, the beyond-use date of the final products (active pharmaceutical ingredients + vehicle) was at least 90 days for all suspensions with regard to both temperatures. This suggests that the vehicle is stable for compounding active pharmaceutical ingredients from different pharmacological classes. Copyright© by International Journal of Pharmaceutical Compounding, Inc.

A semi-active suspension control algorithm for vehicle comprehensive vertical dynamics performance

NASA Astrophysics Data System (ADS)

Nie, Shida; Zhuang, Ye; Liu, Weiping; Chen, Fan

2017-08-01

Comprehensive performance of the vehicle, including ride qualities and road-holding, is essentially of great value in practice. Many up-to-date semi-active control algorithms improve vehicle dynamics performance effectively. However, it is hard to improve comprehensive performance for the conflict between ride qualities and road-holding around the second-order resonance. Hence, a new control algorithm is proposed to achieve a good trade-off between ride qualities and road-holding. In this paper, the properties of the invariant points are analysed, which gives an insight into the performance conflicting around the second-order resonance. Based on it, a new control algorithm is proposed. The algorithm employs a novel frequency selector to balance suspension ride and handling performance by adopting a medium damping around the second-order resonance. The results of this study show that the proposed control algorithm could improve the performance of ride qualities and suspension working space up to 18.3% and 8.2%, respectively, with little loss of road-holding compared to the passive suspension. Consequently, the comprehensive performance can be improved by 6.6%. Hence, the proposed algorithm is of great potential to be implemented in practice.

The effect of a multi-axis suspension on whole body vibration exposures and physical stress in the neck and low back in agricultural tractor applications.

PubMed

Kim, Jeong Ho; Dennerlein, Jack T; Johnson, Peter W

2018-04-01

Whole body vibration (WBV) exposures are often predominant in the fore-aft (x) or lateral (y) axis among off-road agricultural vehicles. However, as the current industry standard seats are designed to reduce mainly vertical (z) axis WBV exposures, they may be less effective in reducing drivers' exposure to multi-axial WBV. Therefore, this laboratory-based study aimed to determine the differences between a single-axial (vertical) and multi-axial (vertical + lateral) suspension seat in reducing WBV exposures, head acceleration, self-reported discomfort, and muscle activity (electromyography) of the major muscle of the low back, neck and shoulders. The results showed that the multi-axial suspension seat had significantly lower WBV exposures compared to the single-axial suspension seats (p' < 0.04). Similarly, the multi-axial suspension seat had lower head acceleration and muscle activity of the neck, shoulder, and low back compared to the single-axial suspension seat; some but not all of the differences were statistically significant. These results indicate that the multi-axial suspension seat may reduce the lateral WBV exposures and associated muscular loading in the neck and low back in agricultural vehicle operators. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

PubMed

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 <.05 for all comparisons); in particular, the acceleration was reduced by 50% in the higher frequency range (4-20 Hz). A reduction in the vibration intensity was perceived by the participants along the y- and z-axes (p =.009 and p =.003, respectively). Implications for the future development of suspension systems are discussed.

Evaluation of the Stability of Mercaptopurine Suspension Compounded in a Commercial Vehicle and the Determination of an Appropriate Beyond-use Date.

PubMed

Peacock, Gina F; Sauvageot, Jurgita; Hill, Ashley; Killian, Alyssa

2016-01-01

Mercaptopurine is commonly used to treat acute lymphoblastic leukemia and has historically been commercially available only in tablet form. Since tablets may be difficult for children and elderly patients to swallow, many pharmacists have compounded mercaptopurine suspensions. The U.S. Food and Drug Administration recently approved a commercial suspension, but it is not widely available at this time. Therefore, pharmacists may still need to compound mercaptopurine suspension for use in areas where it is not available or if the commercial suspension is in short supply. Stability studies must be conducted in order to assign appropriate beyond-use dates for compounded preparations. The objective of this study was to evaluate the stability of extemporaneously compounded suspensions using commercially available mercaptopurine tablets, as well as active pharmaceutical ingredient in a vehicle of Ora-Sweet and Ora-Plus (1:1) stored in plastic and glass containers at room temperature. Each mercaptopurine preparation was analyzed using a validated stability-indicating high-performance liquid chromatography method at the following time points: 0, 7, 14, 21, 30, 60, and 90 days. Suspensions were also observed for changes in appearance or odor, and pH was tested at each time point. The suspension compounded from Roxane generic tablets was extremely viscous and was therefore eliminated from the study. All other suspensions showed no observed physical changes and maintained greater than 93% of initial concentration of mercaptopurine for the entire study period.

Multiobjective optimisation of bogie suspension to boost speed on curves

NASA Astrophysics Data System (ADS)

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.

Feasibility Analysis and Evaluation of an Adaptive Tracked Vehicle Suspension and Control System

DTIC Science & Technology

1975-06-01

CONTROL SYSTEM FINAL REPORT JUNE 1975 Contract No. DAAE07-72-C-017 D D C •W 6 1976 B t> y Robert M. Salemka National Water Lift Company A...spring rate which is as soft as a hydropneumatic system. 3.3 Adaptive Control The adaptive control was achieved by switching the jounce damping relief...inherently included in this type of system. The solenoid valves are of the normally closed type so that with no electrical power , the system will

32 CFR 935.51 - Motor vehicle violations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 6 2010-07-01 2010-07-01 false Motor vehicle violations. 935.51 Section 935.51... REGULATIONS WAKE ISLAND CODE Penalties § 935.51 Motor vehicle violations. Whoever is found guilty of a... than 30 days, or suspension or revocation of his motor vehicle operator's permit, or any combination or...

32 CFR 935.51 - Motor vehicle violations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 32 National Defense 6 2011-07-01 2011-07-01 false Motor vehicle violations. 935.51 Section 935.51... REGULATIONS WAKE ISLAND CODE Penalties § 935.51 Motor vehicle violations. Whoever is found guilty of a... than 30 days, or suspension or revocation of his motor vehicle operator's permit, or any combination or...

Deployment loads data from a free-flight investigation of all flexible parawings having 371.612 sq meters (4000 sq feet) of wing area

NASA Technical Reports Server (NTRS)

Croom, D. R.

1971-01-01

A free-flight test program to determine the deployment characteristics of all-flexible parawings was conducted. Both single-keel and twin-keel parawings having a wing area of 4000 square feet with a five-stage reefing system were tested by use of a bomb-type instrumented test vehicle. Several twin-keel-parawing tests were also made by using an instrumented controllable sled-type test vehicle. The systems were launched from either a C-130 or a C-119 carrier airplane, and a programer parachute was used to bring the test vehicle to a proper dynamic pressure and near-vertical flight path prior to deployment of the parawing system. The free-flight deployment loads data are presented in the form of time histories of individual suspension-line loads and total loads.

Suspension-line wave motion during the lines-first parachute unfurling process

NASA Technical Reports Server (NTRS)

Poole, L. R.; Whitesides, J. L.

1974-01-01

A new mathematical approach to modeling the lines-first parachute unfurling process is presented. The unfurling process is treated as two distinct phases: a suspension-line unfurling phase, during which a massless-spring model of the suspension-line elasticity may be employed; and a canopy unfurling phase, during which a formulation considering suspension-line wave mechanics is employed. Histories of unfurled length and tension at the vehicle obtained using the model are compared with flight test data, and generally good agreement is observed.

Hierarchical control of ride height system for electronically controlled air suspension based on variable structure and fuzzy control theory

NASA Astrophysics Data System (ADS)

Xu, Xing; Zhou, Kongkang; Zou, Nannan; Jiang, Hong; Cui, Xiaoli

2015-09-01

The current research of air suspension mainly focuses on the characteristics and design of the air spring. In fact, electronically controlled air suspension (ECAS) has excellent performance in flexible height adjustment during different driving conditions. However, the nonlinearity of the ride height adjusting system and the uneven distribution of payload affect the control accuracy of ride height and the body attitude. Firstly, the three-point measurement system of three height sensors is used to establish the mathematical model of the ride height adjusting system. The decentralized control of ride height and the centralized control of body attitude are presented to design the ride height control system for ECAS. The exact feedback linearization method is adopted for the nonlinear mathematical model of the ride height system. Secondly, according to the hierarchical control theory, the variable structure control (VSC) technique is used to design a controller that is able to adjust the ride height for the quarter-vehicle anywhere, and each quarter-vehicle height control system is independent. Meanwhile, the three-point height signals obtained by three height sensors are tracked to calculate the body pitch and roll attitude over time, and then by calculating the deviation of pitch and roll and its rates, the height control correction is reassigned based on the fuzzy algorithm. Finally, to verify the effectiveness and performance of the proposed combined control strategy, a validating test of ride height control system with and without road disturbance is carried out. Testing results show that the height adjusting time of both lifting and lowering is over 5 s, and the pitch angle and the roll angle of body attitude are less than 0.15°. This research proposes a hierarchical control method that can guarantee the attitude stability, as well as satisfy the ride height tracking system.

Design and analysis of a magneto-rheological damper for an all terrain vehicle

NASA Astrophysics Data System (ADS)

Krishnan Unni, R.; Tamilarasan, N.

2018-02-01

A shock absorber design intended to replace the existing conventional shock absorber with a controllable system using a Magneto-rheological damper is introduced for an All Terrain Vehicle (ATV) that was designed for Baja SAE competitions. Suspensions are a vital part of an All Terrain Vehicles as it endures various surfaces and requires utmost attention while designing. COMSOL multi-physics software is used for applications that have coupled physics problems and is a unique tool that is used for the designing and analysis phase of the Magneto-rheological damper for the considered application and the model is optimized based on Taguchi using DOE software. The magneto-rheological damper is designed to maximize the damping force with the measured geometric constraints for the All Terrain Vehicle.

REVIEW ARTICLE: Sensors for automotive telematics

NASA Astrophysics Data System (ADS)

Turner, J. D.; Austin, L.

2000-02-01

This article reviews the current practice in sensors and sensor applications for automotive and traffic-control systems. Sensors to control engine fuelling, ignition and transmission (known as the powertrain) are reviewed and the likely course of future development is discussed in the light of regulatory and market requirements as well as trends in sensor design and manufacture. Sensor needs for suspension, braking and control of traction are also reviewed and the likely introduction of wheel and tyre sensors to enhance driving safety is discussed. The recent trend towards vehicle-mounted devices to sense the vehicle's environment (such as radar, optical, ultrasound, capacitive and image-based systems) and the implications of the introduction of safety-critical automotive systems such as adaptive cruise control are discussed. Sensors for initiating the deployment of safety systems such as airbags, together with transducers for disconnecting fuel pumps and vehicle batteries in the event of a crash, are reviewed. The paper includes a brief discussion of highway-based sensors for measuring vehicle speed and presence and concludes with a discussion of the likely future developments in the field.

76 FR 53072 - Certification; Importation of Vehicles and Equipment Subject to Federal Safety, Bumper, and Theft...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-25

... used as a basis for the non-automatic suspension of an RI registration, deletes redundant text from... Part 592 as a Basis for the Non-Automatic Suspension or Revocation of an RI Registration B. Deletion of... violations of the regulations in part 592 as a basis for the non-automatic suspension or revocation of an RI...

Development and optimization of an energy-regenerative suspension system under stochastic road excitation

NASA Astrophysics Data System (ADS)

Huang, Bo; Hsieh, Chen-Yu; Golnaraghi, Farid; Moallem, Mehrdad

2015-11-01

In this paper a vehicle suspension system with energy harvesting capability is developed, and an analytical methodology for the optimal design of the system is proposed. The optimization technique provides design guidelines for determining the stiffness and damping coefficients aimed at the optimal performance in terms of ride comfort and energy regeneration. The corresponding performance metrics are selected as root-mean-square (RMS) of sprung mass acceleration and expectation of generated power. The actual road roughness is considered as the stochastic excitation defined by ISO 8608:1995 standard road profiles and used in deriving the optimization method. An electronic circuit is proposed to provide variable damping in the real-time based on the optimization rule. A test-bed is utilized and the experiments under different driving conditions are conducted to verify the effectiveness of the proposed method. The test results suggest that the analytical approach is credible in determining the optimality of system performance.

Automatic generation of the non-holonomic equations of motion for vehicle stability analysis

NASA Astrophysics Data System (ADS)

Minaker, B. P.; Rieveley, R. J.

2010-09-01

The mathematical analysis of vehicle stability has been utilised as an important tool in the design, development, and evaluation of vehicle architectures and stability controls. This paper presents a novel method for automatic generation of the linearised equations of motion for mechanical systems that is well suited to vehicle stability analysis. Unlike conventional methods for generating linearised equations of motion in standard linear second order form, the proposed method allows for the analysis of systems with non-holonomic constraints. In the proposed method, the algebraic constraint equations are eliminated after linearisation and reduction to first order. The described method has been successfully applied to an assortment of classic dynamic problems of varying complexity including the classic rolling coin, the planar truck-trailer, and the bicycle, as well as in more recent problems such as a rotor-stator and a benchmark road vehicle with suspension. This method has also been applied in the design and analysis of a novel three-wheeled narrow tilting vehicle with zero roll-stiffness. An application for determining passively stable configurations using the proposed method together with a genetic search algorithm is detailed. The proposed method and software implementation has been shown to be robust and provides invaluable conceptual insight into the stability of vehicles and mechanical systems.

Design of a robotic vehicle with self-contained intelligent wheels

NASA Astrophysics Data System (ADS)

Poulson, Eric A.; Jacob, John S.; Gunderson, Robert W.; Abbott, Ben A.

1998-08-01

The Center for Intelligent Systems has developed a small robotic vehicle named the Advanced Rover Chassis 3 (ARC 3) with six identical intelligent wheel units attached to a payload via a passive linkage suspension system. All wheels are steerable, so the ARC 3 can move in any direction while rotating at any rate allowed by the terrain and motors. Each intelligent wheel unit contains a drive motor, steering motor, batteries, and computer. All wheel units are identical, so manufacturing, programing, and spare replacement are greatly simplified. The intelligent wheel concept would allow the number and placement of wheels on the vehicle to be changed with no changes to the control system, except to list the position of all the wheels relative to the vehicle center. The task of controlling the ARC 3 is distributed between one master computer and the wheel computers. Tasks such as controlling the steering motors and calculating the speed of each wheel relative to the vehicle speed in a corner are dependent on the location of a wheel relative to the vehicle center and ar processed by the wheel computers. Conflicts between the wheels are eliminated by computing the vehicle velocity control in the master computer. Various approaches to this distributed control problem, and various low level control methods, have been explored.

Feasibility of amlodipine besylate, chloroquine phosphate, dapsone, phenytoin, pyridoxine hydrochloride, sulfadiazine, sulfasalazine, tetracycline hydrochloride, trimethoprim and zonisamide in SyrSpend(®) SF PH4 oral suspensions.

PubMed

Ferreira, Anderson O; Polonini, Hudson C; Silva, Sharlene L; Patrício, Fernando B; Brandão, Marcos Antônio F; Raposo, Nádia R B

2016-01-25

The objective of this study was to evaluate the feasibility of 10 commonly used active pharmaceutical ingredients (APIs) compounded in oral suspensions using an internationally used suspending vehicle (SyrSpend(®) SF PH4 liquid): (i) amlodipine, (as besylate) 1.0mg/mL; (ii) chloroquine phosphate,15.0 mg/mL; (iii) dapsone, 2.0 mg/mL; (iv) phenytoin, 15.0 mg/mL; (v) pyridoxine hydrochloride, 50.0 mg/mL; (vi) sulfadiazine, 100.0 mg/mL; (vii) sulfasalazine, 100.0 mg/mL; (viii) tetracycline hydrochloride, 25.0 mg/mL; (ix) trimethoprim, 10.0 mg/mL; and (x) zonisamide, 10.0 mg/mL. All suspensions were stored both at controlled refrigeration (2-8 °C) and controlled room temperature (20-25 °C). Feasibility was assessed by measuring the percent recovery at varying time points throughout a 90-day period. API quantification was performed by high-performance liquid chromatography (HPLC-UV), via a stability-indicating method. Given the percentage of recovery of the APIs within the suspensions, the expiration date of the final products (API+vehicle) was at least 90 days for all suspensions with regard to both the controlled temperatures. This suggests that the vehicle is stable for compounding APIs from different pharmacological classes. Copyright © 2015 Elsevier B.V. All rights reserved.

Effects of oral administration of a commercial activated charcoal suspension on serum osmolality and lactate concentration in the dog.

PubMed

Burkitt, Jamie M; Haskins, Steve C; Aldrich, Janet; Jandrey, Karl E; Rezende, Marlis L; Boyle, Jennifer E

2005-01-01

The purpose of this investigation was to determine the effects of an activated charcoal (AC) suspension containing propylene glycol and glycerol on serum osmolality, osmolal gap, and lactate concentration in dogs. Six healthy adult dogs were administered 4 g/kg AC in a commercially available suspension that contained propylene glycol and glycerol as vehicles. Blood samples were taken before and 1, 4, 6, 8, 12, and 24 hours after the administration of the test suspension. Samples were analyzed for osmolality, blood gases, and concentrations of lactate, sodium, potassium, serum urea nitrogen, and glucose. Osmolal gaps were calculated for each time point. Mean serum osmolality, osmolal gap, and lactate concentration were significantly increased after suspension administration compared to baseline. Serum osmolality increased from 311 mOsm/kg at baseline to 353 mOsm/kg, osmolal gap increased from 5 to 52 mOsm/kg, and lactate concentration increased from 1.9 to 4.5 mmol/L after suspension administration (all P < .01). Three of the 6 dogs vomited between 1 and 3 hours after the administration of the test suspension, and 4 of 6 dogs were lethargic. All dogs drank frequently after AC administration. Commercial AC suspension administered at a clinically relevant dose increases serum osmolality, osmolal gap, and lactate concentration in dogs. These laboratory measures and the clinical signs of vomiting, lethargy, and increased frequency of drinking might complicate the diagnosis or monitoring of some intoxications (such as ethylene glycol) in dogs that have previously received AC suspension containing propylene glycol, glycerol, or both as vehicles.

Ex vivo biomechanical characterization of syringe-needle ejections for intracerebral cell delivery.

PubMed

Wahlberg, Brendon; Ghuman, Harmanvir; Liu, Jessie R; Modo, Michel

2018-06-15

Intracerebral implantation of cell suspensions is finding its clinical translation with encouraging results in patients with stroke. However, the survival of cells in the brain remains poor. Although the biological potential of neural stem cells (NSCs) is widely documented, the biomechanical effects of delivering cells through a syringe-needle remain poorly understood. We here detailed the biomechanical forces (pressure, shear stress) that cells are exposed to during ejection through different sized needles (20G, 26G, 32G) and syringes (10, 50, 250 µL) at relevant flow rates (1, 5, 10 µL/min). A comparison of 3 vehicles, Phosphate Buffered Saline (PBS), Hypothermosol (HTS), and Pluronic, indicated that less viscous vehicles are favorable for suspension with a high cell volume fraction to minimize sedimentation. Higher suspension viscosity was associated with greater shear stress. Higher flow rates with viscous vehicle, such as HTS reduced viability by ~10% and also produced more apoptotic cells (28%). At 5 µL/min ejection using a 26G needle increased neuronal differentiation for PBS and HTS suspensions. These results reveal the biological impact of biomechanical forces in the cell delivery process. Appropriate engineering strategies can be considered to mitigate these effects to ensure the efficacious translation of this promising therapy.

Simulation of Hazards and Poses for a Rocker-Bogie Rover

NASA Technical Reports Server (NTRS)

Backes, Paul; Norris, Jeffrey; Powell, Mark; Tharp, Gregory

2004-01-01

Provisions for specification of hazards faced by a robotic vehicle (rover) equipped with a rocker-bogie suspension, for prediction of collisions between the vehicle and the hazards, and for simulation of poses of the vehicle at selected positions on the terrain have been incorporated into software that simulates the movements of the vehicle on planned paths across the terrain. The software in question is that of the Web Interface for Telescience (WITS), selected aspects of which have been described in a number of prior NASA Tech Briefs articles. To recapitulate: The WITS is a system of computer software that enables scientists, located at geographically dispersed computer terminals connected to the World Wide Web, to command instrumented robotic vehicles (rovers) during exploration of Mars and perhaps eventually of other planets. The WITS also has potential for adaptation to terrestrial use in telerobotics and other applications that involve computer-based remote monitoring, supervision, control, and planning.

49 CFR 38.73 - Doorways.

Code of Federal Regulations, 2014 CFR

2014-10-01

... inches and the height of the vehicle floor shall be within plus or minus 5/8 inch of the platform height. Vertical alignment may be accomplished by vehicle air suspension, automatic ramps or lifts, or any combination. (2) Exception. New vehicles operating in existing stations may have a floor height within plus or...

49 CFR 38.73 - Doorways.

Code of Federal Regulations, 2013 CFR

2013-10-01

... inches and the height of the vehicle floor shall be within plus or minus 5/8 inch of the platform height. Vertical alignment may be accomplished by vehicle air suspension, automatic ramps or lifts, or any combination. (2) Exception. New vehicles operating in existing stations may have a floor height within plus or...

36 CFR 1192.53 - Doorways.

Code of Federal Regulations, 2012 CFR

2012-07-01

... between each vehicle door at rest and the platform shall be no greater than 3 inches and the height of the vehicle floor shall be within plus or minus 5/8 inch of the platform height under all normal passenger load conditions. Vertical alignment may be accomplished by vehicle air suspension or other suitable...

49 CFR 38.73 - Doorways.

Code of Federal Regulations, 2012 CFR

2012-10-01

... inches and the height of the vehicle floor shall be within plus or minus 5/8 inch of the platform height. Vertical alignment may be accomplished by vehicle air suspension, automatic ramps or lifts, or any combination. (2) Exception. New vehicles operating in existing stations may have a floor height within plus or...

36 CFR 1192.53 - Doorways.

Code of Federal Regulations, 2014 CFR

2014-07-01

... between each vehicle door at rest and the platform shall be no greater than 3 inches and the height of the vehicle floor shall be within plus or minus 5/8 inch of the platform height under all normal passenger load conditions. Vertical alignment may be accomplished by vehicle air suspension or other suitable...

49 CFR 38.73 - Doorways.

Code of Federal Regulations, 2011 CFR

2011-10-01

... inches and the height of the vehicle floor shall be within plus or minus 5/8 inch of the platform height. Vertical alignment may be accomplished by vehicle air suspension, automatic ramps or lifts, or any combination. (2) Exception. New vehicles operating in existing stations may have a floor height within plus or...

On the dynamic response at the wheel axle of a pneumatic tire

NASA Astrophysics Data System (ADS)

Kung, L. E.; Soedel, W.; Yang, T. Y.

1986-06-01

A method for calculating the steady state displacement response and force transmission at the wheel axle of a pneumatic tire-suspension system due to a steady state force or displacement excitation at the tire to ground contact point is developed. The method requires the frequency responses (or receptances)_of both tire-wheel and suspension units. The frequency response of the tire-wheel unit is obtained by using the modal expansion method. The natural frequencies and mode shapes of the tire-wheel unit are obtained by using a geometrically non-linear, ring type, thin shell finite element of laminate composite. The frequency response of the suspension unit is obtained analytically. These frequency responses are used to calculate the force-input and the displacement-input responses at the wheel axle. This method allows the freedom of designing a vehicle and its tires independently and still achieving optimum dynamic performance.

Wheelset curving guidance using H∞ control

NASA Astrophysics Data System (ADS)

Qazizadeh, Alireza; Stichel, Sebastian; Feyzmahdavian, Hamid Reza

2018-03-01

This study shows how to design an active suspension system for guidance of a rail vehicle wheelset in curve. The main focus of the study is on designing the controller and afterwards studying its effect on the wheel wear behaviour. The controller is designed based on the closed-loop transfer function shaping method and ? control strategy. The study discusses designing of the controller for both nominal and uncertain plants and considers both stability and performance. The designed controllers in Simulink are then applied to the vehicle model in Simpack to study the wheel wear behaviour in curve. The vehicle type selected for this study is a two-axle rail vehicle. This is because this type of vehicle is known to have very poor curving performance and high wheel wear. On the other hand, the relative simpler structure of this type of vehicle compared to bogie vehicles make it a more economic choice. Hence, equipping this type of vehicle with the active wheelset steering is believed to show high enough benefit to cost ratio to remain attractive to rail vehicle manufacturers and operators.

Thermoresponsive Copolypeptide Hydrogel Vehicles for Central Nervous System Cell Delivery.

PubMed

Zhang, Shanshan; Burda, Joshua E; Anderson, Mark A; Zhao, Ziru; Ao, Yan; Cheng, Yin; Sun, Yi; Deming, Timothy J; Sofroniew, Michael V

2015-08-10

Biomaterial vehicles have the potential to facilitate cell transplantation in the central nervous system (CNS). We have previously shown that highly tunable ionic diblock copolypeptide hydrogels (DCH) can provide sustained release of hydrophilic and hydrophobic molecules in the CNS. Here, we show that recently developed non-ionic and thermoresponsive DCH called DCH T exhibit excellent cytocompatibility. Neural stem cell (NSC) suspensions in DCH T were easily injected as liquids at room temperature. DCH T with a viscosity tuned to prevent cell sedimentation and clumping significantly increased the survival of NSC passed through injection cannulae. At body temperature, DCH T self-assembled into hydrogels with a stiffness tuned to that of CNS tissue. After injection in vivo , DCH T significantly increased by three-fold the survival of NSC grafted into healthy CNS. In injured CNS, NSC injected as suspensions in DCH T distributed well in non-neural lesion cores, integrated with healthy neural cells at lesion perimeters and supported regrowing host nerve fibers. Our findings show that non-ionic DCH T have numerous advantageous properties that make them useful tools for in vivo delivery of cells and molecules in the CNS for experimental investigations and potential therapeutic strategies.

The impact of hybrid and electric powertrains on vehicle dynamics, control systems and energy regeneration

NASA Astrophysics Data System (ADS)

Crolla, David A.; Cao, Dongpu

2012-01-01

The background to the development of so-called green or low-carbon vehicles continues to be relentlessly reviewed throughout the literature. Research and development (R&D) on novel powertrains - often based on electric or hybrid technology - has been dominating automotive engineering around the world for the first two decades of the twenty-first century. Inevitably, most of the R&D has focused on powertrain technology and energy management challenges. However, as new powertrains have started to become commercially available, their effects on other aspects of vehicle performance have become increasingly important. This article focuses on the review of the integration of new electrified powertrains with the vehicle dynamics and control systems. The integration effects can be discussed in terms of three generic aspects of vehicle motions, namely roll-plane, pitch-plane and yaw-plane, which however are strongly coupled. The topic on regenerative suspension is further discussed. It quickly becomes clear that this integration poses some interesting future engineering challenges to maintain currently accepted levels of ride, handling and stability performance.

32 CFR 634.11 - Administrative due process for suspensions and revocations.

Code of Federal Regulations, 2013 CFR

2013-07-01

... drunk driving or driving under the influence offenses, reliable evidence readily available will be.... (9) Hearing on suspension actions under § 634.9(a) for drunk or impaired driving pending resolution... (CONTINUED) LAW ENFORCEMENT AND CRIMINAL INVESTIGATIONS MOTOR VEHICLE TRAFFIC SUPERVISION Driving Privileges...

32 CFR 634.11 - Administrative due process for suspensions and revocations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... drunk driving or driving under the influence offenses, reliable evidence readily available will be.... (9) Hearing on suspension actions under § 634.9(a) for drunk or impaired driving pending resolution... (CONTINUED) LAW ENFORCEMENT AND CRIMINAL INVESTIGATIONS MOTOR VEHICLE TRAFFIC SUPERVISION Driving Privileges...

49 CFR 384.208 - Notification of disqualification.

Code of Federal Regulations, 2010 CFR

2010-10-01

... operate a commercial motor vehicle for at least 60 days, the State must notify the State that issued the license of the disqualification, revocation, suspension, or cancellation. (b) The notification must..., suspension, or cancellation. The notification and the information it provides must be recorded on the CDLIS...

Technical assessment of maglev system concepts. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lever, J.H.

1998-10-01

The Government Maglev System Assessment Team operated from 1991 to 1993 as part of the National Maglev Initiative. They assessed the technical viability of four US Maglev system concepts, using the French TGV high speed train and the German TR07 Maglev system as assessment baselines. Maglev in general offers advantages that include high speed potential, excellent system control, high capacity, low energy consumption, low maintenance, modest land requirements, low operating costs, and ability to meet a variety of transportation missions. Further, the US Maglev concepts could provide superior performance to TR07 for similar cost or similar performance for less cost.more » They also could achieve both lower trip times and lower energy consumption along typical US routes. These advantages result generally from the use of large gap magnetic suspensions, more powerful linear synchronous motors and tilting vehicles. Innovative concepts for motors, guideways, suspension, and superconducting magnets all contribute to a potential for superior long term performance of US Maglev systems compared with TGV and TR07.« less

Galenics of dermal products--vehicles, properties and drug release.

PubMed

Daniels, Rolf; Knie, Ulrich

2007-05-01

The efficiency, tolerability, and applicability of topical agents are directly related to employed vehicles. Thus to achieve optimum topical therapy, a solid knowledge of the vehicles, their composition, and their physical and dermato-pharmacological actions are important. Common vehicles are complex mixtures consisting of diverse ingredients belonging to six major groups, i. e. hydrophilic and lipophilic bases, emulsifiers, gel-forming agents, preservatives, and antioxidants. This makes it possible to optimize both the cosmetic features and to adjust a vehicle to the properties of an incorporated drug and site of application. On the other hand it makes it difficult to make a proper choice between several alternatives or to use it in individual prescriptions. In order to simplify the selection of a formulation, it is useful to categorize them systemically into several groups, such as ointments, creams, gels, emulsions, and suspensions. Within these groups some general rules can be derived for the selection of a vehicle with respect to skin conditions and the application site. When active substances are incorporated into a base the dermato-biopharmaceutical properties of the whole system (drug + vehicle) also have to be considered. If for a given vehicle drug transport into the skin does not suffice, several methods are described to facilitate its penetration, such as by hydrating the skin or by adding chemical penetration enhancers.

A new fuzzy sliding mode controller for vibration control systems using integrated-structure smart dampers

NASA Astrophysics Data System (ADS)

Dzung Nguyen, Sy; Kim, Wanho; Park, Jhinha; Choi, Seung-Bok

2017-04-01

Vibration control systems using smart dampers (SmDs) such as magnetorheological and electrorheological dampers (MRD and ERD), which are classified as the integrated structure-SmD control systems (ISSmDCSs), have been actively researched and widely used. This work proposes a new controller for a class of ISSmDCSs in which high accuracy of SmD models as well as increment of control ability to deal with uncertainty and time delay are to be expected. In order to achieve this goal, two formualtion steps are required; a non-parametric SmD model based on an adaptive neuro-fuzzy inference system (ANFIS) and a novel fuzzy sliding mode controller (FSMC) which can weaken the model error of the ISSmDCSs and hence provide enhanced vibration control performances. As for the formulation of the proposed controller, first, an ANFIS controller is desgned to identify SmDs using the improved control algorithm named improved establishing neuro-fuzzy system (establishing neuro-fuzzy system). Second, a new control law for the FSMC is designed via Lyapunov stability analysis. An application to a semi-active MRD vehicle suspension system is then undertaken to illustrate and evaluate the effectiveness of the proposed control method. It is demonstrated through an experimental realization that the FSMC proposed in this work shows superior vibration control performance of the vehicle suspension compared to other surveyed controller which have similar structures to the FSMC, such as fuzzy logic and sliding mode control.

Identification and assessment of permeability enhancing vehicles for transdermal delivery of glucosamine hydrochloride.

PubMed

Han, In Hee; Choi, Sung-Up; Nam, Dae Young; Park, Young Mi; Kang, Myung Joo; Kang, Kyoung Hoon; Kim, Yong Min; Bae, Gunho; Oh, Il Young; Park, Jong Hyeok; Ye, Jin Soo; Choi, Yoon Bae; Kim, Duk Ki; Lee, Jaehwi; Choi, Young Wook

2010-02-01

As an initial step to develop the transdermal delivery system of glucosamine hydrochloride (GL-HCl), the permeation study across the rat skin in vitro was performed to identify the most efficient vehicle with regard to the ability to deliver GL-HCl transdermally. The GL-HCl formulations such as o/w cream, liposome suspension, liposomal gel, and liquid crystalline vehicles were prepared and compared for transdermal flux of GL-HCl. The liquid crystalline vehicles were more effective in increasing the skin permeation of GL-HCl than o/w cream and liposomal vehicles. Of the liquid crystalline vehicles tested, the permeation enhancing ability of the cubic phase was greater than that of the hexagonal phase when the nanoparticle dispersion was used. The skin permeation enhancing ability of the cubic nanoparticles for GL-HCl was further increased by employing both oleic acid and polyethylene glycol 200. Therefore, the cubic liquid crystalline nanodispersion containing oleic acid and PEG 200 can provide a possibility of clinical application of transdermal GL-HCl.

36 CFR § 1192.53 - Doorways.

Code of Federal Regulations, 2013 CFR

2013-07-01

... between each vehicle door at rest and the platform shall be no greater than 3 inches and the height of the vehicle floor shall be within plus or minus 5/8 inch of the platform height under all normal passenger load conditions. Vertical alignment may be accomplished by vehicle air suspension or other suitable...

Optimization of Casting Design Parameters on Fabrication of Reliable Semi-Solid Aluminum Suspension Control Arm

NASA Astrophysics Data System (ADS)

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.

Administrative license suspension: Does length of suspension matter?

PubMed

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.

Explicit Nonlinear Finite Element Geometric Analysis of Parabolic Leaf Springs under Various Loads

PubMed Central

Kong, Y. S.; Omar, M. Z.; Chua, L. B.; Abdullah, S.

2013-01-01

This study describes the effects of bounce, brake, and roll behavior of a bus toward its leaf spring suspension systems. Parabolic leaf springs are designed based on vertical deflection and stress; however, loads are practically derived from various modes especially under harsh road drives or emergency braking. Parabolic leaf springs must sustain these loads without failing to ensure bus and passenger safety. In this study, the explicit nonlinear dynamic finite element (FE) method is implemented because of the complexity of experimental testing A series of load cases; namely, vertical push, wind-up, and suspension roll are introduced for the simulations. The vertical stiffness of the parabolic leaf springs is related to the vehicle load-carrying capability, whereas the wind-up stiffness is associated with vehicle braking. The roll stiffness of the parabolic leaf springs is correlated with the vehicle roll stability. To obtain a better bus performance, two new parabolic leaf spring designs are proposed and simulated. The stress level during the loadings is observed and compared with its design limit. Results indicate that the newly designed high vertical stiffness parabolic spring provides the bus a greater roll stability and a lower stress value compared with the original design. Bus safety and stability is promoted, as well as the load carrying capability. PMID:24298209

Explicit nonlinear finite element geometric analysis of parabolic leaf springs under various loads.

PubMed

Kong, Y S; Omar, M Z; Chua, L B; Abdullah, S

2013-01-01

This study describes the effects of bounce, brake, and roll behavior of a bus toward its leaf spring suspension systems. Parabolic leaf springs are designed based on vertical deflection and stress; however, loads are practically derived from various modes especially under harsh road drives or emergency braking. Parabolic leaf springs must sustain these loads without failing to ensure bus and passenger safety. In this study, the explicit nonlinear dynamic finite element (FE) method is implemented because of the complexity of experimental testing A series of load cases; namely, vertical push, wind-up, and suspension roll are introduced for the simulations. The vertical stiffness of the parabolic leaf springs is related to the vehicle load-carrying capability, whereas the wind-up stiffness is associated with vehicle braking. The roll stiffness of the parabolic leaf springs is correlated with the vehicle roll stability. To obtain a better bus performance, two new parabolic leaf spring designs are proposed and simulated. The stress level during the loadings is observed and compared with its design limit. Results indicate that the newly designed high vertical stiffness parabolic spring provides the bus a greater roll stability and a lower stress value compared with the original design. Bus safety and stability is promoted, as well as the load carrying capability.

? observer-based decentralised fuzzy control design for nonlinear interconnected systems: an application to vehicle dynamics

NASA Astrophysics Data System (ADS)

Latrach, Chedia; Kchaou, Mourad; Guéguen, Hervé

2017-05-01

In this study, a decentralised output learning control strategy for a class of nonlinear interconnected systems is studied. Based on Takagi-Sugeno fuzzy (TS) model to approximate the considered interconnected nonlinear systems, a decentralised observer-based control scheme is designed to override the external disturbances such that the ? performance is achieved. The appealing attributes of this approach include: (1) the closed-loop system exhibits a robustness against nonlinear interconnections and external disturbance, (2) by one-step procedure, the gain matrices of observer and controller are obtained on a single step. In simulation results, the controller design is evaluated on the steering stability of a car where the nonlinear model describes the side slip, roll and yaw motions of the automotive vehicle equipped with four-wheel-steering and active suspension.

Ensuring Safe Exploration: Ares Launch Vehicle Integrated Vehicle Ground Vibration Testing

NASA Technical Reports Server (NTRS)

Tuma, M. L.; Chenevert, D. J.

2010-01-01

Integrated vehicle ground vibration testing (IVGVT) will be a vital component for ensuring the safety of NASA's next generation of exploration vehicles to send human beings to the Moon and beyond. A ground vibration test (GVT) measures the fundamental dynamic characteristics of launch vehicles during various phases of flight. The Ares Flight & Integrated Test Office (FITO) will be leading the IVGVT for the Ares I crew launch vehicle at Marshall Space Flight Center (MSFC) from 2012 to 2014 using Test Stand (TS) 4550. MSFC conducted similar GVT for the Saturn V and Space Shuttle vehicles. FITO is responsible for performing the IVGVT on the Ares I crew launch vehicle, which will lift the Orion crew exploration vehicle to low Earth orbit, and the Ares V cargo launch vehicle, which can launch the lunar lander into orbit and send the combined Orionilander vehicles toward the Moon. Ares V consists of a six-engine core stage with two solid rocket boosters and an Earth departure stage (EDS). The same engine will power the EDS and the Ares I second stage. For the Ares IVGVT, the current plan is to test six configurations in three unique test positions inside TS 4550. Position 1 represents the entire launch stack at liftoff (using inert first stage segments). Position 2 consists of the entire launch stack at first stage burn-out (using empty first stage segments). Four Ares I second stage test configurations will be tested in Position 3, consisting of the Upper Stage and Orion crew module in four nominal conditions: J-2X engine ignition, post Launch Abort System (LAS) jettison, critical slosh mass, and J-2X burn-out. Because of long disuse, TS 4550 is being repaired and reactivated to conduct the Ares I IVGVT. The Shuttle-era platforms have been removed and are being replaced with mast climbers that provide ready access to the test articles and can be moved easily to support different positions within the test stand. The electrical power distribution system for TS 4550 was upgraded. Two new cranes will help move test articles at the test stand and at the Redstone Arsenal railhead where first stage segments will be received in 2011. The Hydrodynamic Support systems (HDSs) used for Saturn and Shuttle have been disassembled and evaluated for use during IVGVT. Analyses indicate that the 45-year-old HDSs can be refurbished to support the Ares I IVGVT. An alternate concept for a pneumatic suspension system is also being explored. A decision on which suspension system configuration to use for IVGVT will be made in 2010. In the next three years, the team will complete the updates to TS 4550, upgrade the test and data collection equipment, and finalize the configurations of the test articles to be used in the IVGVT. With NASA's GVT capabilities reestablished, the FITO team will be well positioned to perform similar work on Ares V, the largest exploration launch vehicle NASA has ever built. The GVT effort continues NASA's 50-year commitment to using testing and data analysis for safer, more reliable launch vehicles.

Research on optimization of test cycles for comfort to the special vehicles

NASA Astrophysics Data System (ADS)

Mitroi, Marian; Chiru, Anghel

2017-10-01

The comfort of vehicles, regardless of their type is represent a requirement to by fulfilled in the context of current technological developments special vehicles generally move under different soil, time, or season conditions, and the land in which the vehicles move is complex and varied in the physical structure. Due to the high level of involvement in the driveability, safety and comfort of automotive, suspension system is a key factor with major implications for vibration and noise, affecting the human body. The objective of the research is related to determining the test cycles of special vehicles that are approaching real situations, to determine the level of comfort. The evaluate of the degree of comfort will be realized on acceleration values recorded, especially the vertical ones that have the highest influence on the human body. Thus, in this way the tests can be established needed to determine the level of comfort required for each particular type of special vehicle. The utility of the test cycles to optimize comfort is given to the accurate identification of the specific test needs, depending on the each vehicle.

32 CFR 636.7 - Extensions of suspensions and revocations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 4 2010-07-01 2010-07-01 true Extensions of suspensions and revocations. 636.7 Section 636.7 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) LAW ENFORCEMENT AND CRIMINAL INVESTIGATIONS MOTOR VEHICLE TRAFFIC SUPERVISION (SPECIFIC INSTALLATIONS) Fort Stewart, Georgia § 636.7 Extensions of...

32 CFR 636.4 - Administrative due process for suspensions and revocations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 4 2010-07-01 2010-07-01 true Administrative due process for suspensions and revocations. 636.4 Section 636.4 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) LAW ENFORCEMENT AND CRIMINAL INVESTIGATIONS MOTOR VEHICLE TRAFFIC SUPERVISION (SPECIFIC INSTALLATIONS) Fort Stewart, Georgia § 636.4...

32 CFR 634.9 - Suspension or revocation of driving or privately owned vehicle registration privileges.

Code of Federal Regulations, 2010 CFR

2010-07-01

... TRAFFIC SUPERVISION Driving Privileges § 634.9 Suspension or revocation of driving or privately owned... revocation of installation driving privileges or POV registrations, for lawful reasons unrelated to traffic... occurring on the installation or in areas subject to military traffic supervision. After a review of...

Structural Technology Evaluation and Analysis Program (STEAP). Delivery Order 0037: Prognosis-Based Control Reconfiguration for an Aircraft with Faulty Actuator to Enable Performance in a Degraded State

DTIC Science & Technology

2010-12-01

computers in 1953. HIL motion simulators were also built for the dynamic testing of vehicle com- ponents (e.g. suspensions, bodies ) with hydraulic or...complex, comprehensive mechanical systems can be simulated in real-time by parallel computers; examples include multi- body sys- tems, brake systems...hard constraints in a multivariable control framework. And the third aspect is the ability to perform online optimization. These aspects results in

Double row loop-coil configuration for high-speed electrodynamic maglev suspension, guidance, propulsion and guideway directional switching

DOEpatents

He, Jianliang; Rote, Donald M.

1996-01-01

A stabilization and propulsion system comprising a series of loop-coils arranged in parallel rows wherein two rows combine to form one of two magnetic rails. Levitation and lateral stability are provided when the induced field in the magnetic rails interacts with the superconducting magnets mounted on the magnetic levitation vehicle. The loop-coils forming the magnetic rails have specified dimensions and a specified number of turns and by constructing differently these specifications, for one rail with respect to the other, the angle of tilt of the vehicle can be controlled during directional switching. Propulsion is provided by the interaction of a traveling magnetic wave associated with the coils forming the rails and the super conducting magnets on the vehicle.

Double row loop-coil configuration for high-speed electrodynamic maglev suspension, guidance, propulsion and guideway directional switching

DOEpatents

He, J.; Rote, D.M.

1996-05-21

A stabilization and propulsion system are disclosed comprising a series of loop-coils arranged in parallel rows wherein two rows combine to form one of two magnetic rails. Levitation and lateral stability are provided when the induced field in the magnetic rails interacts with the superconducting magnets mounted on the magnetic levitation vehicle. The loop-coils forming the magnetic rails have specified dimensions and a specified number of turns and by constructing differently these specifications, for one rail with respect to the other, the angle of tilt of the vehicle can be controlled during directional switching. Propulsion is provided by the interaction of a traveling magnetic wave associated with the coils forming the rails and the superconducting magnets on the vehicle. 12 figs.

Effects of Resveratrol on the Recovery of Muscle Mass Following Disuse in the Plantaris Muscle of Aged Rats

PubMed Central

Bennett, Brian T.; Mohamed, Junaith S.; Alway, Stephen E.

2013-01-01

Aging is associated with poor skeletal muscle regenerative ability following extended periods of hospitalization and other forms of muscular disuse. Resveratrol (3,5,4’-trihydroxystilbene) is a natural phytoalexin which has been shown in skeletal muscle to improve oxidative stress levels in muscles of aged rats. As muscle disuse and reloading after disuse increases oxidative stress, we hypothesized that resveratrol supplementation would improve muscle regeneration after disuse. A total of thirty-six male Fisher 344 × Brown Norway rats (32 mo.) were treated with either a water vehicle or resveratrol via oral gavage. The animals received hindlimb suspension for 14 days. Thereafter, they were either sacrificed or allowed an additional 14 day period of cage ambulation during reloading. A total of six rats from the vehicle and the resveratrol treated groups were used for the hindlimb suspension and recovery protocols. Furthermore, two groups of 6 vehicle treated animals maintained normal ambulation throughout the experiment, and were used as control animals for the hindlimb suspension and reloading groups. The data show that resveratrol supplementation was unable to attenuate the decreases in plantaris muscle wet weight during hindlimb suspension but it improved muscle mass during reloading after hindlimb suspension. Although resveratrol did not prevent fiber atrophy during the period of disuse, it increased the fiber cross sectional area of type IIA and IIB fibers in response to reloading after hindlimb suspension. There was a modest enhancement of myogenic precursor cell proliferation in resveratrol-treated muscles after reloading, but this failed to reach statistical significance. The resveratrol-associated improvement in type II fiber size and muscle mass recovery after disuse may have been due to decreases in the abundance of pro-apoptotic proteins Bax, cleaved caspase 3 and cleaved caspase 9 in reloaded muscles. Resveratrol appears to have modest therapeutic benefits for improving muscle mass after disuse in aging. PMID:24349525

John F. Kennedy Space Center's Wireless Hang Angle Instrumentation System

NASA Technical Reports Server (NTRS)

Kohler, Jeff

2009-01-01

The technology is a high-precision, wireless inclinometer. The system was designed for monitoring the suspension angle of the Orbiter vehicle during loading onto the Solid Rocket Boosters of the Space Shuttle. Originally, operators manually measured the alignment of the Orbiter with a hand-held inclinometer on a nonrigid surface. The measurement was open to interpretation by the loader. If the Orbiter is misaligned, it can crush ball joints and delay the loading while repairs are made. With this system, the Orbiter can be loaded without damage and without manual measurement.

Stability of Acetazolamide, Baclofen, Dipyridamole, Mebeverine Hydrochloride, Propylthiouracil, Quinidine Sulfate, and Topiramate Oral Suspensions in SyrSpend SF PH4.

PubMed

Ferreira, Anderson de Oliveira; Polonini, Hudson; da Silva, Sharlene Loures; Aglio, Natália Cristina Buzinari; Abreu, Jordana; Fernandes, Brandão Marcos Antônio

2017-01-01

The objective of this study was to evaluate the stability of 7 commonly used active pharmaceutical ingredients compounded in oral suspensions using an internationally used suspending vehicle (SyrSpend SF PH4): acetazolamide 25.0 mg/mL, baclofen 10.0 mg/mL, dipyridamole 10.0 mg/mL, mebeverine hydrochloride 10.0 mg/mL, propylthiouracil 5.0 mg/mL, quinidine sulfate 10.0 mg/mL, and topiramate 5.0 mg/mL. All suspensions were stored both at controlled refrigerated (2°C to 8°C) and room temperature (20°C to 25°C). Stability was assessed by measuring the percentage recovery at varying time points throughout a 90-day period. Active pharmaceutical ingredient quantification was performed by ultraviolet (UV) high-performance liquid chromatography, via a stability-indicating method. Given the percentage of recovery of the active pharmaceutical ingredients within the suspensions, the beyond-use date of the final products (active pharmaceutical ingredient + vehicle) was at least 90 days for all suspensions with regards to both temperatures. This suggests that SyrSpend SF PH4 is suitable for compounding active pharmaceutical ingredients from different pharmacological classes. Copyright© by International Journal of Pharmaceutical Compounding, Inc.

Real-Time and High-Fidelity Simulation Environment for Autonomous Ground Vehicle Dynamics

NASA Technical Reports Server (NTRS)

Cameron, Jonathan; Myint, Steven; Kuo, Calvin; Jain, Abhi; Grip, Havard; Jayakumar, Paramsothy; Overholt, Jim

2013-01-01

This paper reports on a collaborative project between U.S. Army TARDEC and Jet Propulsion Laboratory (JPL) to develop a unmanned ground vehicle (UGV) simulation model using the ROAMS vehicle modeling framework. Besides modeling the physical suspension of the vehicle, the sensing and navigation of the HMMWV vehicle are simulated. Using models of urban and off-road environments, the HMMWV simulation was tested in several ways, including navigation in an urban environment with obstacle avoidance and the performance of a lane change maneuver.

Maglev-rail intermodal equipment and suspension study. Final report, July 1991-February 1993

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gilcrease, E.E.; Gillam, C.M.

1993-02-01

The physical and operational characteristics of four existing and planned maglev systems were surveyed pertinent to the intermodal interface for each system. The maglev systems investigated were: Grumman New York State' (Configuration 002) Maglev; Transrapid Intercity (Transrapid 07) Maglev; HSST Passive Intermediate Speed (HSST-300) Maglev; and Japan Railways Vertical Magnet (Configuration MLU 002) Maglev. The focus of the study was to investigate the feasibility of using existing railroad right-of-way to access center-city terminals in one of three possible methods: Maglev vehicles traveling over existing railroad tracks with the use of steel guide wheels and some means of exterior propulsion; maglevmore » vehicles transferred onto modified railroad flatcars and transported over existing railroad tracks with locomotive power; or new grade-separated maglev guideways on existing railroad rights-of-way.« less

The Shock and Vibration Bulletin. Part 3. Vehicle Dynamics and Vibration: Test and Criteria.

DTIC Science & Technology

1983-05-01

transformation. As stability is assumed in forward motion. used here it invariably means the Hydraulic suspension is formed for each group static...are used to calcu- late the random rms stress according to the type Tolerable sound pressure levels were of structure. Appropriate random S-N curves...DC AIRCRAFT SURVIVABILITY Dale B. Atkinson, Chairman, Joint Technical Coordinating Group on Aircraft Survivability, Naval Air Systems Command

Stability of extemporaneous erlotinib, lapatinib, and imatinib oral suspensions.

PubMed

Li, Quan; Liu, Zhaoying; Kolli, Shamalatha; Wetz, Karen; Griffith, Niesha; Poi, Ming J

2016-09-01

The stability of extemporaneously prepared erlotinib, lapatinib, and imatinib oral liquid dosage forms using two commercially available vehicles when stored at 4 and 25 °C was evaluated. Three batches of extemporaneous oral suspensions were prepared for each drug. Erlotinib and lapatinib tablets were crushed and mixed in a 1:1 mixture of Ora-Plus:Ora-Sweet solution to yield 10- and 50-mg/mL suspensions, respectively. Imatinib tablets were crushed and mixed in Ora-Sweet solution to yield a 40-mg/mL suspension. Suspensions were stored in amber plastic bottles, and samples from each bottle were obtained on days 0, 1, 3, 7, 14, and 28. Erlotinib 10-mg/mL and lapatinib 50-mg/mL oral suspensions in a 1:1 mixture of Ora-Plus and Ora-Sweet retained at least 90% of their initial concentration throughout the 28-day study when stored at 25 °C. Visual inspection revealed notable viscosity changes in the erlotinib and lapatinib suspensions stored at 4 °C for 7 days and beyond. The viscosity of these preparations increased with time and was particularly evident with the erlotinib suspension, which exhibited a puddinglike texture. Imatinib 40-mg/mL oral suspension in Ora-Sweet appeared stable for up to 14 days when stored at both 25 and 4 °C. Erlotinib 10-mg/mL and lapatinib 50-mg/mL oral suspensions prepared from commercially available tablets were stable for at least 28 days when prepared in a 1:1 mixture of Ora-Plus:Ora-Sweet at 25 °C. Imatinib 40-mg/mL oral suspension prepared from commercially available tablets was stable for up to 14 days when prepared in Ora-Sweet and stored at 25 and 4 °C. Copyright © 2016 by the American Society of Health-System Pharmacists, Inc. All rights reserved.

Developing the Next Generation NATO Reference Mobility Model

DTIC Science & Technology

2016-06-27

acquisition • design UNCLASSIFIED: Distribution Statement A. Approved for public release; distribution is unlimited.(#27992) Vehicle Dynamics Model...and numerical resolution – for use in vehicle design , acquisition and operational mobility planning 27 June 2016 An open architecture was established...the current empirical methods for simulating vehicle and suspension designs . – Industry wide shortfall with tire dynamics and soft soil behavior

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

NASA Astrophysics Data System (ADS)

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).

Comparative Study of the Ride Quality of TRACV Suspension Alternatives

DOT National Transportation Integrated Search

1979-06-01

A linearized model of the pitch-heave dynamics of a Tracked Ram Air Cushion Vehicle is presented. This model is based on aerodynamic theory which has been verified by wind tunnel and towed model experiments. The vehicle is assumed to be equipped with...

Diesel Vehicle Maintenance Competencies.

ERIC Educational Resources Information Center

Braswell, Robert; And Others

Designed to provide a model set of competencies, this manual presents tasks which were identified by employers, employees, and teachers as important in a postsecondary diesel vehicle maintenance curriculum. The tasks are divided into seven major component areas of instruction: chassis and suspension, diesel engines, diesel fuel, electrical,…

Effectiveness of the Ohio vehicle action and administrative license suspension laws

DOT National Transportation Integrated Search

2000-01-01

Author's abstract: This report presents a study of the effectiveness of two laws in the State of Ohio, one of which provided for the impounding and immobilization (with a "club" device) of the vehicles of multiple drunk driving offenders and drivers ...

Mass Properties Measurement in the X-38 Project

NASA Technical Reports Server (NTRS)

Peterson, Wayne L.

2004-01-01

This paper details the techniques used in measuring the mass properties for the X-38 family of test vehicles. The X-38 Project was a NASA internal venture in which a series of test vehicles were built in order to develop a Crew Return Vehicle (CRV) for the International Space Station. Three atmospheric test vehicles and one spaceflight vehicle were built to develop the technologies required for a CRV. The three atmospheric test vehicles have undergone flight-testing by a combined team from the NASA Johnson Space Center and the NASA Dryden Flight Research Center. The flight-testing was performed at Edward's Air Force Base in California. The X-38 test vehicles are based on the X-24A, which flew in the '60s and '70s. Scaled Composites, Inc. of Mojave, California, built the airframes and the vehicles were outfitted at the NASA Johnson Space Center in Houston, Texas. Mass properties measurements on the atmospheric test vehicles included weight and balance by the three-point suspension method, four-point suspension method, three load cells on jackstands, and on three in-ground platform scales. Inertia measurements were performed as well in which Ixx, Iyy, Izz, and Ixz were obtained. This paper describes each technique and the relative merits of each. The proposed measurement methods for an X-38 spaceflight test vehicle will also be discussed. This vehicle had different measurement challenges, but integrated vehicle measurements were never conducted. The spaceflight test vehicle was also developed by NASA and was scheduled to fly on the Space Shuttle before the project was cancelled.

Hydraulic actuation technology for full- and semi-active railway suspensions

NASA Astrophysics Data System (ADS)

Goodall, Roger; Freudenthaler, Gerhard; Dixon, Roger

2014-12-01

The paper describes a simulation study that provides a comprehensive comparison between full-active and semi-active suspensions for improving the vertical ride quality of railway vehicles. It includes an assessment of the ride quality benefits that can theoretically be achieved with idealised devices, and also examines the impact of real devices based upon hydraulic actuation technology.

Pre-Alignment Checks. Automotive Mechanics. Steering & Suspension. Instructor's Guide [and] Student Guide.

ERIC Educational Resources Information Center

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 prealignment checks. Covered in the module are the following steps in a prealignment check: checking the ride height of a vehicle, checking the ball joints and the…

Stability of sotalol hydrochloride in extemporaneously prepared oral suspension formulations.

PubMed

Sidhom, Madiha B; Rivera, Nadya; Almoazen, Hassan; Taft, David R; Kirschenbaum, Harold L

2005-01-01

The physical, chemical, and microbial stabilities of extemporaneously compounded oral liquid formulations of sotalol hydrochloride were studied. Sotalol hydrochloride oral liquid suspensions (5mg/mL) were prepared from commercially available tablets (Betapace) in a 1:1 mixture of Ora-Plus: Ora-Sweet, a 1:1 mixture of Ora-Plus:Ora-Sweet SF, and a 1:2.4 mixture of simple syrup:methylcellulose vehicle. Six batches of each formulation were prepared; three were stored at refrigerated temperature (2 deg to 8 deg C) and three at room temperature (20 deg to 25 deg C). Samples were collected from each batch weekly for 6 weeks, and again at 12 weeks. Samples were analyzed by means of a high-performance liquid chromatographic method, and the concentrations obtained were compared to the theoretical time zero value. Samples were examined for pH, odor, color, and consistency changes. The suspensions also were evaluated for their microbial stability. Sotalol hydrochloride oral liquid suspensions (5mg/mL) were chemically stable for 12 weeks regardless of storage conditions (room temperature or refrigerated). Bacterial growth was not supported by any of the formulations. Suspensions stored at refrigerated temperature retained better physical quality (e.g., odor, color, and consistency) than suspensions stored at room temperature. Overall, this study demonstrates that oral formulations of sotalol hydrochloride can be readily prepared with commercially available vehicles. The method of preparation is relatively simple, the materials are relatively inexpensive, and the products have a shelf-life of at least 12 weeks.

Low-Cost MEMS Sensors and Vision System for Motion and Position Estimation of a Scooter

PubMed Central

Guarnieri, Alberto; Pirotti, Francesco; Vettore, Antonio

2013-01-01

The possibility to identify with significant accuracy the position of a vehicle in a mapping reference frame for driving directions and best-route analysis is a topic which is attracting a lot of interest from the research and development sector. To reach the objective of accurate vehicle positioning and integrate response events, it is necessary to estimate position, orientation and velocity of the system with high measurement rates. In this work we test a system which uses low-cost sensors, based on Micro Electro-Mechanical Systems (MEMS) technology, coupled with information derived from a video camera placed on a two-wheel motor vehicle (scooter). In comparison to a four-wheel vehicle; the dynamics of a two-wheel vehicle feature a higher level of complexity given that more degrees of freedom must be taken into account. For example a motorcycle can twist sideways; thus generating a roll angle. A slight pitch angle has to be considered as well; since wheel suspensions have a higher degree of motion compared to four-wheel motor vehicles. In this paper we present a method for the accurate reconstruction of the trajectory of a “Vespa” scooter; which can be used as alternative to the “classical” approach based on GPS/INS sensor integration. Position and orientation of the scooter are obtained by integrating MEMS-based orientation sensor data with digital images through a cascade of a Kalman filter and a Bayesian particle filter. PMID:23348036

Low-Cost MEMS sensors and vision system for motion and position estimation of a scooter.

PubMed

Guarnieri, Alberto; Pirotti, Francesco; Vettore, Antonio

2013-01-24

The possibility to identify with significant accuracy the position of a vehicle in a mapping reference frame for driving directions and best-route analysis is a topic which is attracting a lot of interest from the research and development sector. To reach the objective of accurate vehicle positioning and integrate response events, it is necessary to estimate position, orientation and velocity of the system with high measurement rates. In this work we test a system which uses low-cost sensors, based on Micro Electro-Mechanical Systems (MEMS) technology, coupled with information derived from a video camera placed on a two-wheel motor vehicle (scooter). In comparison to a four-wheel vehicle; the dynamics of a two-wheel vehicle feature a higher level of complexity given that more degrees of freedom must be taken into account. For example a motorcycle can twist sideways; thus generating a roll angle. A slight pitch angle has to be considered as well; since wheel suspensions have a higher degree of motion compared to four-wheel motor vehicles. In this paper we present a method for the accurate reconstruction of the trajectory of a "Vespa" scooter; which can be used as alternative to the "classical" approach based on GPS/INS sensor integration. Position and orientation of the scooter are obtained by integrating MEMS-based orientation sensor data with digital images through a cascade of a Kalman filter and a Bayesian particle filter.

Stability of an extemporaneously compounded minoxidil oral suspension.

PubMed

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.

23 CFR 192.3 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-04-01

... SUSPENSION § 192.3 Definitions. As used in this part: (a) Convicted includes adjudicated under juvenile... individual to operate a motor vehicle on highways. (c) Drug offense means: (1) The possession, distribution... Substances Act, or (2) The operation of a motor vehicle under the influence of such a substance. (d...

Spatial multibody modeling and vehicle dynamics analysis of advanced vehicle technologies

NASA Astrophysics Data System (ADS)

Letherwood, Michael D.; Gunter, David D.; Gorsich, David J.; Udvare, Thomas B.

2004-08-01

The US Army vision, announced in October of 1999, encompasses people, readiness, and transformation. The goal of the Army vision is to transition the entire Army into a force that is strategically responsive and dominant at every point of the spectrum of operations. The transformation component will be accomplished in three ways: the Objective Force, the Legacy (current) Force, and the Interim Force. The objective force is not platform driven, but rather the focus is on achieving capabilities that will operate as a "system of systems." As part of the Objective Force, the US Army plans to begin production of the Future Combat System (FCS) in FY08 and field the first unit by FY10 as currently defined in the FCS solicitation(1). As part of the FCS program, the Future Tactical Truck System (FTTS) encompasses all US Army tactical wheeled vehicles and its initial efforts will focus only on the heavy class. The National Automotive Center (NAC) is using modeling and simulation to demonstrate the feasibility and operational potential of advanced commercial and military technologies with application to new and existing tactical vehicles and to describe potential future vehicle capabilities. This document will present the results of computer-based, vehicle dynamics performance assessments of FTTS concepts with such features as hybrid power sources, active suspensions, skid steering, and in-hub electric drive motors. Fully three-dimensional FTTS models are being created using commercially available modeling and simulation methodologies such as ADAMS and DADS and limited vehicle dynamics validation studies are will be performed.

Numerical solution of equations governing longitudinal suspension line wave motion during the parachute unfurling process. Ph.D. Thesis - George Washington Univ., Washington, D. C.

NASA Technical Reports Server (NTRS)

Poole, L. R.

1973-01-01

Equations are presented which govern the dynamics of the lines-first parachute unfurling process, including wave motion in the parachute suspension lines. Techniques are developed for obtaining numerical solutions to the governing equations. Histories of tension at test data, and generally good agreement is observed. Errors in computed results are attributed to several areas of uncertainty, the most significant being a poorly defined boundary condition on the wave motion at the vehicle-suspension line boundary.

Evaluation of ATV Track Systems for Winter Mountain Operations

DTIC Science & Technology

2011-06-01

charge utile. Importance des résultats et perspectives : Selon ces essais limités, comparativement à une motoneige moderne, les VTT à chenilles...of this document, but the products seem similar in design , with subtle differences in frame, suspension, track depth, etc. Each of the companies sell...because the transmission of this vehicle seems to be designed for high-speed operation, rather than low-speed torque. It should also be noted that the

Dynamic interactions of an integrated vehicle-electromagnetic energy harvester-tire system subject to uneven road excitations

NASA Astrophysics Data System (ADS)

Xing, Jing Tang; Sun, Zhe; Zhou, Sulian; Tan, Mingyi

2017-04-01

An investigation is undertaken of an integrated mechanical-electromagnetic coupling system consisting of a rigid vehicle with heave, roll, and pitch motions, four electromagnetic energy harvesters and four tires subject to uneven road excitations in order to improve the passengers' riding comfort and harvest the lost engine energy due to uneven roads. Following the derived mathematical formulations and the proposed solution approaches, the numerical simulations of this interaction system subject to a continuous sinusoidal road excitation and a single ramp impact are completed. The simulation results are presented as the dynamic response curves in the forms of the frequency spectrum and the time history, which reveals the complex interaction characteristics of the system for vibration reductions and energy harvesting performance. It has addressed the coupling effects on the dynamic characteristics of the integrated system caused by: (1) the natural modes and frequencies of the vehicle; (2) the vehicle rolling and pitching motions; (3) different road excitations on four wheels; (4) the time delay of a road ramp to impact both the front and rear wheels, etc., which cannot be tackled by an often used quarter vehicle model. The guidelines for engineering applications are given. The developed coupling model and the revealed concept provide a means with analysis idea to investigate the details of four energy harvester motions for electromagnetic suspension designs in order to replace the current passive vehicle isolators and to harvest the lost engine energy. Potential further research directions are suggested for readers to consider in the future.

PRODUCTION OF SLIP CAST CALCIA HOLLOWWARE

DOEpatents

Stoddard, S.D.; Nuckolls, D.E.; Cowan, R.E.

1963-12-31

A method for producing slip cast calcia hollow ware in which a dense calcia grain is suspended in isobutyl acetate or a mixture of tertiary amyl alcohol and o-xylene is presented. A minor amount of triethanolamine and oleic acid is added to the suspension vehicle as viscosity adjusting agents and the suspension is cast in a plaster mold, dried, and fired. (AEC)

40 CFR 86.612-97 - Suspension and revocation of certificates of conformity.

Code of Federal Regulations, 2013 CFR

2013-07-01

... ENGINES (CONTINUED) Selective Enforcement Auditing of New Light-Duty Vehicles, Light-Duty Trucks, and... configuration produced at more than one plant do not conform to the regulations with respect to which the... to that configuration for vehicles manufactured by the manufacturer in other plants of the...

40 CFR 86.612-97 - Suspension and revocation of certificates of conformity.

Code of Federal Regulations, 2011 CFR

2011-07-01

... ENGINES (CONTINUED) Selective Enforcement Auditing of New Light-Duty Vehicles, Light-Duty Trucks, and... configuration produced at more than one plant do not conform to the regulations with respect to which the... to that configuration for vehicles manufactured by the manufacturer in other plants of the...

40 CFR 86.612-97 - Suspension and revocation of certificates of conformity.

Code of Federal Regulations, 2012 CFR

2012-07-01

... ENGINES (CONTINUED) Selective Enforcement Auditing of New Light-Duty Vehicles, Light-Duty Trucks, and... configuration produced at more than one plant do not conform to the regulations with respect to which the... to that configuration for vehicles manufactured by the manufacturer in other plants of the...

The influence of suspension components friction on race car vertical dynamics

NASA Astrophysics Data System (ADS)

Benini, Claudio; Gadola, Marco; Chindamo, Daniel; Uberti, Stefano; Marchesin, Felipe P.; Barbosa, Roberto S.

2017-03-01

This work analyses the effect of friction in suspension components on a race car vertical dynamics. It is a matter of fact that race cars aim at maximising their performance, focusing the attention mostly on aerodynamics and suspension tuning: suspension vertical and rolling stiffness and damping are parameters to be taken into account for an optimal setup. Furthermore, friction in suspension components must not be ignored. After a test session carried out with a F4 on a Four Poster rig, friction was detected on the front suspension. The real data gathered allow the validation of an analytical model with friction, confirming that its influence is relevant for low frequency values closed to the car pitch natural frequency. Finally, some setup proposals are presented to describe what should be done on actual race cars in order to correct vehicle behaviour when friction occurs.

The Influence of End-Stop Buffer Characteristics on the Severity of Suspension Seat End-Stop Impacts

NASA Astrophysics Data System (ADS)

Wu, X.; Griffin, M. J.

1998-08-01

Suspension seat end-stop impacts may be a source of increased risk of injury for the drivers of some machines and work vehicles, such as off-road vehicles. Most suspension seats use rubber buffers to reduce the severity of end-stop impacts, but they still result in a high magnitude of acceleration being transmitted to drivers when an end-stop impact occurs. An experimental study has been conducted to investigate the effect of buffer stiffness and buffer damping on the severity of end-stop impacts. The results show that the end-stop impact performance of suspension seats with only bottom buffers can be improved by the use of both top and bottom buffers. The force-deflection characteristics of rubber buffers had a significant influence on the severity of end-stop impacts. The optimum buffer should have medium stiffness which is nearly linear and occurs over a long deflection, without being compressed to its high stiffness stage. It is shown, theoretically, that buffer damping is capable of significantly reducing the severity of end-stop impacts. However, since current rubber material provides only low damping, alternative materials to those in current use, or either passive or active damping devices, are required.

Integration of Mirror Design with Suspension System Using NASA's New Mirror Modeling Software

NASA Technical Reports Server (NTRS)

Arnold, William R., Sr.; Bevan, Ryan M.; Stahl, H. Philip

2013-01-01

Advances in mirror fabrication are making very large space based telescopes possible. In many applications, only monolithic mirrors can meet the performance requirements. The existing and near-term planned heavy launch vehicles place a premium on lowest possible mass, and then available payload shroud sizes limit near term designs to 4 meter class mirrors. Practical 8 meter class and beyond designs could encourage planners to include larger shrouds, if it can be proven that such mirrors can be manufactured. These two factors, lower mass and larger mirrors, present the classic optimization problem. There is a practical upper limit to how large of a mirror can be supported by a purely kinematic mount system handling both operational and launch loads. This paper shows how the suspension system and mirror blank need to be designed simultaneously. We will also explore the concepts of auxiliary support systems which act only during launch and disengage on orbit. We will define required characteristics of these systems and show how they can substantially reduce the mirror mass.

Integration of Mirror Design with Suspension System using NASA's New Mirror Modeling Software

NASA Technical Reports Server (NTRS)

Arnold,William R., Sr.; Bevan, Ryan M.; Stahl, Philip

2013-01-01

Advances in mirror fabrication are making very large space based telescopes possible. In many applications, only monolithic mirrors can meet the performance requirements. The existing and near-term planned heavy launch vehicles place a premium on lowest possible mass, and then available payload shroud sizes limit near term designs to 4 meter class mirrors. Practical 8 meter class and beyond designs could encourage planners to include larger shrouds, if it can be proven that such mirrors can be manufactured. These two factors, lower mass and larger mirrors, present the classic optimization problem. There is a practical upper limit to how large of a mirror can be supported by a purely kinematic mount system handling both operational and launch loads. This paper shows how the suspension system and mirror blank need to be designed simultaneously. We will also explore the concepts of auxiliary support systems which act only during launch and disengage on orbit. We will define required characteristics of these systems and show how they can substantially reduce the mirror mass.

Randomized, open-label, single-dose, crossover, relative bioavailability study in healthy adults, comparing the pharmacokinetics of rabeprazole granules administered using soft food or infant formula as dosing vehicle versus suspension.

PubMed

Thyssen, An; Solanki, Bhavna; Treem, William

2012-07-01

A sprinkle capsule formulation containing enteric-coated, delayed-release rabeprazole granules is being developed for the treatment of children with gastrointestinal reflux disease. The granules are designed to be mixed with vehicles that facilitate delivery to children, who may be unable to swallow solid formulations. The primary objective of this study-conducted on the sponsor's initiative-was to compare the bioavailability of rabeprazole granules when mixed with various dosing vehicles (small amount of soft food or infant formula) with that of a rabeprazole suspension with inactive vehicle granules (reference), to determine which dosing vehicle can be used to deliver rabeprazole in children. Tolerability was also assessed. This single-center, single-dose, randomized, open-label, 5-period crossover study was conducted in 35 healthy adult subjects. In a randomized sequence, fasting subjects received a single dose of 10-mg rabeprazole granules per treatment period, mixed with small amounts of 1 of 5 dosing vehicles (a strawberry-flavored suspension of rabeprazole granules with inactive vehicle granules reconstituted with water, yogurt [1 tablespoon], applesauce [1 tablespoon], or infant formula [5 mL], or a suspension of rabeprazole granules with inactive vehicle tablet reconstituted with water). Full plasma pharmacokinetic (PK) profiles of rabeprazole and its thioether metabolite were collected; concentrations were estimated via LC-MS/MS. PK properties were estimated using noncompartmental methods; 90% CIs around least squares mean test-to-reference ratios were calculated for C(max) and AUC values. All treatment-emergent adverse events (TEAEs) were recorded and assessed for severity (mild, moderate, or severe) and relationship to study drug. A total of 35 subjects were enrolled (mean age, 38 years; 54.3% female; 100% white; mean weight, 71.4 kg). Thirty-four subjects completed the study. Rabeprazole and rabeprazole thioether plasma PK properties were comparable between all of the dosing vehicles tested. Median T(max) was 2.5 to 3.0 hours, and mean elimination half-life was 1.27 to 1.43 hours. The 90%CIs for the least squares mean ratios for rabeprazole and rabeprazole thioether exposure were within the 80% to 125% bioequivalence limits for all relevant comparisons. All TEAEs were of mild or moderate intensity, with headache being the most commonly reported; 21 subjects (60%) experienced TEAEs during the study. No deaths or serious AEs were reported during the study; 1 subject experienced a TEAE (urinary tract infection) that led to the discontinuation of treatment. In these healthy adult subjects, the bioavailability of rabeprazole granules was comparable between all of the dosing vehicles tested, and rabeprazole was well tolerated. Soft food suitable for young children or infant formula may be appropriate for use as dosing vehicles for rabeprazole granules. Copyright © 2012 Elsevier HS Journals, Inc. All rights reserved.

Adaptive Behavior for Mobile Robots

NASA Technical Reports Server (NTRS)

Huntsberger, Terrance

2009-01-01

The term "System for Mobility and Access to Rough Terrain" (SMART) denotes a theoretical framework, a control architecture, and an algorithm that implements the framework and architecture, for enabling a land-mobile robot to adapt to changing conditions. SMART is intended to enable the robot to recognize adverse terrain conditions beyond its optimal operational envelope, and, in response, to intelligently reconfigure itself (e.g., adjust suspension heights or baseline distances between suspension points) or adapt its driving techniques (e.g., engage in a crabbing motion as a switchback technique for ascending steep terrain). Conceived for original application aboard Mars rovers and similar autonomous or semi-autonomous mobile robots used in exploration of remote planets, SMART could also be applied to autonomous terrestrial vehicles to be used for search, rescue, and/or exploration on rough terrain.

Stability of penethamate, a benzylpenicillin ester prodrug, in oily vehicles.

PubMed

Jain, Rohit; Bork, Olaf; Tucker, Ian G

2015-01-01

Penethamate (PNT) is an ester prodrug of benzylpenicillin which is marketed as dry powder for reconstitution with aqueous vehicle prior to injection. The purpose of this paper was to investigate the chemical stability of PNT in oily formulations to provide a basis for a ready-to-use (RTU) oil-based PNT formulation. The chemical stability of PNT solutions and suspensions in light liquid paraffin (LP), medium chain triglyceride (MIG), ethyl oleate (EO) and sunflower oil (SO) was investigated at 30 °C. Solid state stability of PNT powder and stability of PNT in EO suspensions with different moisture contents were also evaluated. The solubility of PNT in the oils was in order SO > EO > MIG > LP. Degradation of PNT was rapid in oily solutions and less than 10% remained after 7-15 days. Stability of PNT decreased with increase in moisture content in ethyl oleate suspensions. PNT was stable over four weeks in the solid state. Hydrolysis, due to moisture in the oil formulation is not the only degradation mechanism. PNT stability (% drug remaining) in oily suspensions after 3.5 months was in the order LP (96.2%) > MIG (95.4%) > EO (94.1%) > SO (86%). A shelf-life of up to 5.5 years at 30 °C may be achieved for PNT suspension in these oils.

The effect of linear spring number at side load of McPherson suspension in electric city car

NASA Astrophysics Data System (ADS)

Budi, Sigit Setijo; Suprihadi, Agus; Makhrojan, Agus; Ismail, Rifky; Jamari, J.

2017-01-01

The function of the spring suspension on Mc Pherson type is to control vehicle stability and increase ride convenience although having tendencies of side load presence. The purpose of this study is to obtain simulation results of Mc Pherson suspension spring in the electric city car by using the finite element method and determining the side load that appears on the spring suspension. This research is conducted in several stages; they are linear spring designing models with various spring coil and spring suspension modeling using FEM software. Suspension spring is compressed in the vertical direction (z-axis) and at the upper part of the suspension springs will be seen the force that arises towards the x, y, and z-axis to simulate the side load arising on the upper part of the spring. The results of FEM simulation that the side load on the spring toward the x and y-axis which the value gets close to zero is the most stable spring.

Stability of Prednisone in Oral Mix Suspending Vehicle.

PubMed

Friciu, Mihaela; Plourde, Kevin; Leclair, Grégoire; Danopoulos, Panagiota; Savji, Taslim

2015-01-01

The stability of prednisone (5 mg/mL) formulated as a suspension in Oral Mix vehicle was evaluated. Oral Mix is a novel oral, dye-free suspending vehicle developed by Medisca Pharmaceutique Inc. for preparation of extemporaneous dosage forms. This drug was chosen based on its high frequency of prescription among the pediatric population. Suspensions were prepared from both pure active and commercial tablets utilizing two different container closures: amber glass bottles and polypropylene syringes (PreciseDose Dispenser Medisca Pharmaceutique Inc.). Formulations were stored at 5°C or 25°C and organoleptic properties, pH, and concentration were evaluated at predetermined time points up to 90 days. Validated stability-indicating high-performance liquid chromatography methods were developed. Beyond-use date was evaluated by statistical analysis of the overall degradation trend. Prednisone was stable for at least 90 days at 25°C. No changes in organoleptic properties or pH were observed for either of the formulations, and the global stability was roughly equivalent and sometimes superior to the stability of the same drugs in other previously used vehicles. Thus, Oral Mix was found to be a suitable dye-free vehicle for extemporaneous formulations.

Ondansetron: design and development of oral pharmaceutical suspensions.

PubMed

Gallardo Lara, V; Gallardo, M Lopez-Viota; Morales Hernandez, Ma E; Ruiz Martinez, Ma A

2009-02-01

Ondansetron is a carbazol with antiemetic properties that acts as a competitive and selective antagonist for the 5 HT3 serotonin receptors. It is used primarily to control nausea and vomiting caused by cytotoxic chemotherapy and radiotherapy, as well as in postoperative vomiting in gynecological surgery. The main aim of this work was to obtain a stable, long-acting oral suspension of ondansetron. To prolong the action, latexes are used as transport vehicles, specifically we tested, Aquateric, which comprises mainly cellulose acetophthalate. We prepared a complex drug-polymer, and the release profile of ondansetron was evaluated at acid, basic and acid-basic pH. This complex is additioned to a vehicle with xanthan gum and sodium carboxymethylcellulose (CMCNa) as thickeners to retard as much as possible particle sedimentation and thus increase physical stability of the suspension. The results obtained for sediment volume and degree of flocculation suggest that xanthan gum provides the best results, with better organolepticcharacteristics, appearance, physical stability and easy redispersability.

The Influence of Road Bumps Characteristics on the Chaotic Vibration of a Nonlinear Full-Vehicle Model with Driver

NASA Astrophysics Data System (ADS)

Fakhraei, J.; Khanlo, H. M.; Ghayour, M.; Faramarzi, Kh.

In this paper, the chaotic behavior of a ground vehicle system with driver subjected to road disturbances is studied and the relationship between the nonlinear vibration of the vehicle and ride comfort is evaluated. The vehicle system is modeled as fully nonlinear with seven degrees of freedom and an additional degree of freedom for driver (8-DOF). The excitation force is the road irregularities that are assumed as road speed control bumps. The sinusoidal, consecutive half-sine and dented-rectangular waveforms are considered to simulate the road speed control bumps. The nonlinearities of the system are due to the nonlinear springs and dampers that are used in the suspension system and tires. The governing differential equations are extracted under Newton-Euler laws and solved via numerical methods. The chaotic behaviors were studied in more detail with special techniques such as bifurcation diagrams, phase plane portrait, Poincaré map and Lyapunov exponents. The ride comfort was evaluated as the RMS value of the vertical displacement of the vehicle body and driver. Firstly, the effect of amplitude (height) and frequency (vehicle’s speed) of these speed control bumps on chaotic vibrations of vehicle are studied. The obtained results show that various forms of vibrations, such as periodic, subharmonic and chaotic vibrations, can be detected in the system behavior with the change of the height and frequency of speed control bumps and present different types of strange attractors in the vehicle with and without driver. Then, the influence of nonlinear vibration on ride comfort and the relationship between chaotic vibrations of the vehicle and driving comfort are investigated. The results of analyzing the RMS diagrams reveal that the chaotic behaviors can directly affect the driving comfort and lead to the driver’s comfort being reduced. The obtained results can be used in the design of vehicle and road bumps pavement.

Vibration isolation analysis of new design OEM damper for malaysia vehicle suspension system featuring MR fluid

NASA Astrophysics Data System (ADS)

Unuh, M. H.; Muhamad, P.; Norfazrina, H. M. Y.; Ismail, M. A.; Tanasta, Z.

2018-01-01

The applications of semi-active damper employing magnetorheological (MR) fluids keep increasing in fulfilling the demand to control undesired vibration effect. The aim of this study is to introduce the new design of damper for Malaysian vehicle model as well to evaluate its effectiveness in promoting comfort. The vibration isolation performance of the OEM damper featuring MR fluid was analysed physically under real road profile excitation experimentally. An experiment using quarter car rig suspension and LMS SCADAS Mobile was conducted to demonstrate the influence of current in controlling the characteristics of MR fluid in alter the damping behaviour under 5 cm bump impact. Subsequently, the displacement values were measured with respect to time. The new design OEM damper featuring MR fluid was validated by comparing the data with original equipment manufacturer (OEM) passive damper results under the same approach of testing. Comparison of numerical data of the new design OEM damper shown that it can reduce the excitation amplitude up to 40% compared to those obtained by OEM passive damper. Finally, the new design OEM damper featuring MR fluid has effectively isolated the disturbance from the road profile and control the output force.

POGO ground simulation test of H-I launch vehicle's second stage

NASA Astrophysics Data System (ADS)

Ono, Yoshio; Kohsetsu, Yuji; Shibukawa, Kiwao

This paper describes a POGO ground simulation test of the Japanese new second stage for the H-I launch vehicle. It was the final prelaunch verification test of a POGO prevention of the H-I. This test was planned to examine POGO stability and was conducted in a Captive Firing Test (CFT) by mounting a flight-type second stage by a soft suspension system on the CFT test stand which gave the vehicle a pseudo inflight boundary condition of free-free in terms of the vehicle's structural dynamics. There was no indication that implied POGO from the data measured during the CFT. Consequently, this test suggested that the new second stage of the H-I was POGO free. Therefore, it was decided that the first test flight (TF no. 1) of the H-I would be made without a POGO Suppression Device. TF no. 1 was launched successfully on August 13, 1986, and its telemetry data showed no evidence of POGO phenomenon.

Preliminary design for a maglev development facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coffey, H.T.; He, J.L.; Chang, S.L.

1992-04-01

A preliminary design was made of a national user facility for evaluating magnetic-levitation (maglev) technologies in sizes intermediate between laboratory experiments and full-scale systems. A technical advisory committee was established and a conference was held to obtain advice on the potential requirements of operational systems and how the facility might best be configured to test these requirements. The effort included studies of multiple concepts for levitating, guiding, and propelling maglev vehicles, as well as the controls, communications, and data-acquisition and -reduction equipment that would be required in operating the facility. Preliminary designs for versatile, dual 2-MVA power supplies capable ofmore » powering attractive or repulsive systems were developed. Facility site requirements were identified. Test vehicles would be about 7.4 m (25 ft) long, would weigh form 3 to 7 metric tons, and would operate at speeds up to 67 m/s (150 mph) on a 3.3-km (2.05-mi) elevated guideway. The facility would utilize modular vehicles and guideways, permitting the substitution of levitation, propulsion, and guideway components of different designs and materials for evaluation. The vehicle would provide a test cell in which individual suspension or propulsion components or subsystems could be tested under realistic conditions. The system would allow economical evaluation of integrated systems under varying weather conditions and in realistic geometries.« less

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

NASA Technical Reports Server (NTRS)

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.

40 CFR 86.612-97 - Suspension and revocation of certificates of conformity.

Code of Federal Regulations, 2014 CFR

2014-07-01

... ENGINES Selective Enforcement Auditing of New Light-Duty Vehicles, Light-Duty Trucks, and Heavy-Duty... at more than one plant do not conform to the regulations with respect to which the certificate of... configuration for vehicles manufactured by the manufacturer in other plants of the manufacturer. (d) The...

Electric transportation in environmentally planned city of tomorrow. Paper No. 7788

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watkins, B.

1977-01-01

A discussion is given of the operation of the electric monorail trains at Disneyland and Walt Disney World. The all-electric trains are powered by eight 600 V dc motors and use an air suspension system providing excellent riding qualities. A key factor in the overall efficiency is the loading and unloading technique in which the passengers step onto a moving circular platform which is synchronized to the speed of the vehicles being loaded. (PMA)

Evaluation of Active Damping for Reduction of Noise, Vibration and Motion of Ground Vehicles by Multibody Simulation

DTIC Science & Technology

2004-10-01

practical applications of the technology in road vehicles. Active dampers based on several mechanical principles are available on the market ...between sportive and comfortable operating modes. A second type is the feedback of vehicle motion and, consequently, a dynamic suspension control...of-the-art in railway and automotive applications and have found an, albeit yet small, market . Typical representatives of semi-active devices are

Control of maglev vehicles with aerodynamic and guideway disturbances

NASA Technical Reports Server (NTRS)

Flueckiger, Karl; Mark, Steve; Caswell, Ruth; Mccallum, Duncan

1994-01-01

A modeling, analysis, and control design methodology is presented for maglev vehicle ride quality performance improvement as measured by the Pepler Index. Ride quality enhancement is considered through active control of secondary suspension elements and active aerodynamic surfaces mounted on the train. To analyze and quantify the benefits of active control, the authors have developed a five degree-of-freedom lumped parameter model suitable for describing a large class of maglev vehicles, including both channel and box-beam guideway configurations. Elements of this modeling capability have been recently employed in studies sponsored by the U.S. Department of Transportation (DOT). A perturbation analysis about an operating point, defined by vehicle and average crosswind velocities, yields a suitable linearized state space model for multivariable control system analysis and synthesis. Neglecting passenger compartment noise, the ride quality as quantified by the Pepler Index is readily computed from the system states. A statistical analysis is performed by modeling the crosswind disturbances and guideway variations as filtered white noise, whereby the Pepler Index is established in closed form through the solution to a matrix Lyapunov equation. Data is presented which indicates the anticipated ride quality achieved through various closed-loop control arrangements.

a Simplified Method to Design Suspended Cabs for Counterbalance Trucks

NASA Astrophysics Data System (ADS)

LEMERLE, P.; BOULANGER, P.; POIROT, R.

2002-05-01

A “low-frequency” suspension system, placed between the driving cab and chassis of an existing fork lift truck was designed. The aim of this project was to develop a design procedure which is easy to implement and suitable for all types of fork lift trucks. It was also to show how the use of numerical simulation could be helpful to optimize the efficiency of such suspension systems. The cab specifications were: (1) to achieve a vertical vibration attenuation of at least 50% when this truck is tested under severe but realistic conditions, (2) to operate with no specific adjustment for drivers weighing between 60 and 100 kg, (3) to be efficient with a reasonable dynamic stroke (about 3 cm maximum). The suspended cab was modelled using ADAMS software. In the simplified method, the input acceleration signals (at the four fixing points of the cab) were not computed from a vehicle model (chassis and wheels) but directly measured under various driving conditions (passage of two or four wheels over an obstacle with a loaded or unloaded fork lift truck). This model allowed evaluation of the theoretical attenuation, obtained below the driver's seat along the three axes, in comparison with an infinitely rigid suspension. The attenuation ratio was calculated for several values of the characteristics of the suspension components (stiffness and damping). Similarly, for every design value tested, the design constraints were evaluated and at the end of this parametrical study, optimal suspension components were found. Finally, the suspended cab was built according to the results of the parametrical study and measurements subsequently confirmed that the attenuation of vertical accelerations was more than 50%.

Improved oral absorption of dutasteride via Soluplus®-based supersaturable self-emulsifying drug delivery system (S-SEDDS).

PubMed

Lee, Dong Hoon; Yeom, Dong Woo; Song, Ye Seul; Cho, Ha Ra; Choi, Yong Seok; Kang, Myung Joo; Choi, Young Wook

2015-01-15

A novel supersaturable self-emulsifying drug delivery system (S-SEDDS) was formulated to improve the oral absorption of dutasteride (DTS), a 5α-reductase inhibitor that is poorly water-soluble. A supersaturable system was prepared by employing Soluplus(®) (polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer) as a precipitation inhibitor with a conventional SEDDS vehicle consisted of Capryol™ 90, Cremophor(®) EL and Transcutol(®) HP (DTS:SEDDS vehicle:Soluplus(®)=1.0:67.6:10.0 w/v/w). In an in vitro dissolution test in a non-sink condition, the drug dissolution rate from SEDDS was rapidly increased to 72% for an initial period of 5min, but underwent rapid drug precipitation within 2h, decreasing the amount of drug dissolved to one-seventh of its original amount. On the other hand, S-SEDDS resulted in a slower crystallization of DTS by virtue of a precipitation inhibitor, maintaining a 3 times greater dissolution rate after 2h compared to SEDDS. In an in vivo pharmacokinetic study in rats, the S-SEDDS formulation exhibited 3.9-fold greater area-under-curve value than that of the drug suspension and 1.3-fold greater than that of SEDDS. The maximum plasma concentration of S-SEDDS was 5.6- and 2.0-fold higher compared to drug suspension and SEDDS, respectively. The results of this study suggest that the novel supersaturable system may be a promising tool for improving the physicochemical property and oral absorption of the 5α-reductase inhibitor. Copyright © 2014 Elsevier B.V. All rights reserved.

Method and algorithm of automatic estimation of road surface type for variable damping control

NASA Astrophysics Data System (ADS)

Dąbrowski, K.; Ślaski, G.

2016-09-01

In this paper authors presented an idea of road surface estimation (recognition) on a base of suspension dynamic response signals statistical analysis. For preliminary analysis cumulated distribution function (CDF) was used, and some conclusion that various roads have responses values in a different ranges of limits for the same percentage of samples or for the same limits different percentages of samples are located within the range between limit values. That was the base for developed and presented algorithm which was tested using suspension response signals recorded during road test riding over various surfaces. Proposed algorithm can be essential part of adaptive damping control algorithm for a vehicle suspension or adaptive control strategy for suspension damping control.

Railway vehicle body structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1985-01-01

The strength and durability of railway vehicle structures is a major topic of engineering research and design. To reflect this importance the Railway Division of the Institution of Mechanical Engineers organised a conference to discuss all matters relating to railway vehicle design. This book presents the papers discussed in that conference. The contents include: Vehicle body design and the UIC's international contribution; LUL prototype 1986 stock - body structure; vehicle structure for the intermediate capacity transmit system vehicles; car body technology of advanced light rapid transit vehicles; concepts, techniques and experience in the idealization of car body structures for finitemore » element analysis; Calcutta metropolitan railway; design for a lightweight diesel multiple unit body; the design of lightweight inter-city coal structures; the BREL international coach body shell structure; new concepts and design techniques versus material standards; structures of BR diesel electric freight locomotives; structural design philosophy for electric locomotives; suspension design for a locomotive with low structural frequencies; freight wagon structures; a finite element study of coal bodyside panels including the effects of joint flexibility; a fresh approach to the problem of car body design strength; energy absorption in automatic couplings and draw gear; passenger vehicle design loads and structural crashworthiness; design of the front part of railway vehicles (in case of frontal impact); the development of a theoretical technique for rail vehicle structural crashworthiness.« less

Mucoadhesive Properties of Eudragit®RS100, Eudragit®S100, and Poly(ε-caprolactone) Nanocapsules: Influence of the Vehicle and the Mucosal Surface.

PubMed

Chaves, Paula Dos Santos; Frank, Luiza Abrahão; Frank, Alejandro Germán; Pohlmann, Adriana Raffin; Guterres, Sílvia Stanisçuaski; Beck, Ruy Carlos Ruver

2018-05-01

The use of polymers as mucoadhesive materials has been explored in several drug delivery systems. It is well known that the resulting mucoadhesiveness not only depends on the polymers by themselves, but also on the way they are delivered and on the application target. However, little attention has been given to the combined effect of such characteristics. Therefore, the objective of this study is to analyze the mucoadhesion resulting from combined effects of nanocapsules produced with polymers of different ionic properties, Eudragit®RS100, Eudragit®S100, or poly(ε-caprolactone), when they are incorporated into different vehicles (suspension, hydrogel, and powder) and applied on different mucosal surfaces (mucin, porcine vaginal, and buccal mucosa). Mucoadhesion was measured by a tensile stress tester. Our findings show that polymeric self-assembling as nanocapsules improved the mucoadhesion of the polymers. Eudragit®RS100 nanocapsules have the best performance, independently of the vehicle and surface used. Regarding the vehicle, hydrogels showed higher adhesion when compared to suspensions and powders. When considering different types of surfaces, mucin presented a similar pattern like the animal mucosa, but it overestimated the mucoadhesiveness of all formulations. In conclusion, this study demonstrated that the best strategy to achieve high mucoadhesive formulations is by incorporating Eudragit®RS100 nanocapsules in hydrogels. Moreover, mucin is a suitable substrate to compare and screen different formulations but not as a conclusive estimation of the mucoadhesion values that can be achieved. These results are summarized in a decision tree that can help to understand different strategies of combination of these factors and the expected outcomes.

Compounded Apixaban Suspensions for Enteral Feeding Tubes.

PubMed

Caraballo, Maria L; Donmez, Seda; Nathan, Kobi; Zhao, Fang

2017-07-01

Objective: There is limited information on compounded apixaban formulations for administration via enteral feeding tubes. This study was designed to identify a suitable apixaban suspension formulation that is easy to prepare in a pharmacy setting, is compatible with commonly used feeding tubes, and has a beyond-use date of 7 days. Methods: Apixaban suspensions were prepared from commercially available 5-mg Eliquis tablets. Several vehicles and compounding methods were screened for ease of preparation, dosage accuracy, and tube compatibility. Two tubing types, polyurethane and polyvinyl chloride, with varying lengths and diameters, were included in the study. They were mounted on a peg board during evaluation to mimic the patient body position. A 7-day stability study of the selected formulation was also conducted. Results: Vehicles containing 40% to 60% Ora-Plus in water all exhibited satisfactory flowability through the tubes. The mortar/pestle compounding method was found to produce more accurate and consistent apixaban suspensions than the pill crusher or crushing syringe method. The selected formulation, 0.25 mg/mL apixaban in 50:50 Ora-Plus:water, was compatible with both tubing types, retaining >98% drug in posttube samples. The stability study also confirmed that this formulation was stable physically and chemically over 7 days of storage at room temperature. Conclusions: A suitable apixaban suspension formulation was identified for administration via enteral feeding tubes. The formulation consisted of 0.25 mg/mL apixaban in 50:50 Ora-Plus:water. The stability study results supported a beyond-use date of 7 days at room temperature.

Forestry Vehicle

NASA Technical Reports Server (NTRS)

1982-01-01

Power Pack II provides an economical means of moving a power source into remote roadless forest areas. It was developed by Prof. Miles and his associates, working in cooperation with the University of California's Department of Forestry. The team combined its own design of an all-terrain vehicle with a suspension system based on the NASA load equalization technology. Result is an intermediate-sized unit which carries a power source and the powered tools to perform a variety of forest management tasks which cannot be done economically with current equipment. Power Pack II can traverse very rough terrain and climb a 60 degree slope; any one of the wheels can move easily over an obstacle larger than itself. Work is being done on a more advanced Power Pack III.

Factors affecting shear thickening behavior of a concentrated injectable suspension of levodopa.

PubMed

Allahham, Ayman; Stewart, Peter; Marriott, Jennifer; Mainwaring, David

2005-11-01

Previous clinical studies on a subcutaneous injectable suspension of levodopa showed poor injectability into human tissue. When this formulation was rheologically characterised, a clinical shear thickening interval was observed at increased shear rates. The formulation parameters that contributed to this rheological behavior were systematically evaluated with the aim of removing this flow limitation while maintaining the concentration of 60% levodopa to retain the clinical applicability. The three suspension parameters examined were: levodopa volume fraction, concentration of the HPMC suspending vehicle, and particle size distribution. Shear thickening increased with the drug concentration and the critical shear rate was inversely dependent on the drug concentration. Increasing the vehicle concentration retarded the shear thickening but increased the overall suspension viscosity. There was an increase in shear thickening with increased average particle diameter. Combinations of micronized and non-micronized particles were used to prepare bimodal particle size distributions. The rheology of these bimodal distributions resulted in removal of shear thickening. This allowed the preparation of 60% levodopa formulations that showed a range of flow characteristics spanning near Newtonian flow or shear thinning at initial injectable viscosities of about 0.6 Pa.s and final viscosities in the range of 0.1 Pa.s, alleviating the shear thickening limitation of these levodopa formulations.

Extemporaneous suspension of propafenone: attending lack of pediatric formulations in Mexico.

PubMed

Juárez Olguín, Hugo; Flores Pérez, Carmen; Ramírez Mendiola, Blanca; Coria Jiménez, Rafael; Sandoval Ramírez, Eunice; Flores Pérez, Janett

2008-11-01

Physicians have frequently encountered difficulties when prescribing drugs not available in doses suitable for pediatric age groups. Furthermore, children have difficulty swallowing tablets. This study aimed to determine the stability of an oral propafenone suspension made from commercial tablets with a syrup vehicle and to establish its reliable use with children. An extemporaneous suspension of propafenone 1.5 mg/ml was prepared with commercial tablets. Its physicochemical and microbiologic stability was established by constant monitoring during 90 days at room temperature (15 +/- 5 degrees C) and at refrigeration (3-5 degrees C). Plasma levels of propafenona were measured in two children with supraventricular tachycardia at steady state. The suspension was stable, maintaining its original physicochemical and microbiologic properties. Moreover, no apparent changes in color or odor were observed. Plasma levels of propafenone in patients demonstrated therapeutic concentrations after they had taken the suspension, with no unwanted outcome. The conservation of both physicochemical and microbiologic stability of the suspension represents an option for the administration of propafenone to children.

The Pneumatic Actuators As Vertical Dynamic Load Simulators On Medium Weighted Wheel Suspension Mechanism

NASA Astrophysics Data System (ADS)

Ka'ka, Simon; Himran, Syukri; Renreng, Ilyas; Sutresman, Onny

2018-02-01

Almost all of road damage can be caused by dynamic loads of vehicles that fluctuate according to the type of vehicle that passes through. This study aims to calculate the vertical dynamic load of the vehicle actually occurs on road construction by the mechanism of vehicle wheel suspension. Pneumatic cylinders driven by pressurized air directly load the spring and shock absorber installed on the wheels of the vehicle. The load fluctuations of the medium weight categorized vehicles are determined by the regulation of the amount of pressurized air that enters into the pneumatic cylinder chamber, pushing the piston and connecting rods. The displacement that occurs during compression on the spring and shock absorber, is substituted into the equation of vehicle dynamic load while taking into account the spring stiffness constant, and the fluid or damper gas coefficient. The results show that the magnitude of the displacement when the compression force works has significant influences to the amount of vertical dynamic load of the vehicle that overlies the road construction. The presence of dynamic load of vehicles that fluctuates and repeats, also affects on the reduction of road ability to receive the load. Experimental results using pneumatic actuators instead of real dynamic vehicle loads illustrate the characteristics of the relationship between work pressure and dynamic load. If the working pressure of P2 (bar) is greater, the vertical dynamic load Ft (N) that overloads the road structure is also greater. The associate graphs show that the shock absorber has a greater ability to reduce dynamic load vertically that burden the road structure when compared with the ability of screw spring.

Road dust emissions from paved roads measured using different mobile systems.

PubMed

Pirjola, Liisa; Johansson, Christer; Kupiainen, Kaarle; Stojiljkovic, Ana; Karlsson, Hans; Hussein, Tareq

2010-12-01

Very few real-world measurements of road dust suspension have been performed to date. This study compares two different techniques (referred to as Sniffer and Emma) to measure road dust emissions. The main differences between the systems are the construction of the inlet, different instruments for recording particulate matter (PM) levels, and different loads on the wheel axes (the weight of Sniffer was much higher than that of Emma). Both systems showed substantial small-scale variations of emission levels along the road, likely depending on-road surface conditions. The variations observed correlated quite well, and the discrepancies are likely a result of variations in dust load on the road surface perpendicular to the driving direction that cause variations in the measurements depending on slightly different paths driven by the two vehicles. Both systems showed a substantial influence on the emission levels depending on the type of tire used. The summer tire showed much lower suspension than the winter tires (one nonstudded and one studded). However, the relative importance of the nonstudded versus studded tire was rather different. For the ratio of studded/nonstudded, Emma shows higher values on all road sections compared with Sniffer. Both techniques showed increased emission levels with increasing vehicle speed. When the speed increased from 50 to 80 km hr(-1), the relative concentrations increased by 30-170% depending on the tire type and dust load. However, for road sections that were very dirty, Sniffer showed a much higher relative increase in the emission level with the nonstudded tire. Sniffer's absolute concentrations were mostly higher than Emma's. Possible reasons for the differences are discussed in the paper. Both systems can be used for studying relative road dust emissions and for designing air quality management strategies.

Scarecrow

NASA Image and Video Library

2007-10-04

The team developing NASA Mars Science Laboratory calls this test rover Scarecrow because the vehicle does not include a computer brain. Mobility engineers use this test rover to evaluate mobility and suspension performance.

Non-linear modelling and control of semi-active suspensions with variable damping

NASA Astrophysics Data System (ADS)

Chen, Huang; Long, Chen; Yuan, Chao-Chun; Jiang, Hao-Bin

2013-10-01

Electro-hydraulic dampers can provide variable damping force that is modulated by varying the command current; furthermore, they offer advantages such as lower power, rapid response, lower cost, and simple hardware. However, accurate characterisation of non-linear f-v properties in pre-yield and force saturation in post-yield is still required. Meanwhile, traditional linear or quarter vehicle models contain various non-linearities. The development of a multi-body dynamics model is very complex, and therefore, SIMPACK was used with suitable improvements for model development and numerical simulations. A semi-active suspension was built based on a belief-desire-intention (BDI)-agent model framework. Vehicle handling dynamics were analysed, and a co-simulation analysis was conducted in SIMPACK and MATLAB to evaluate the BDI-agent controller. The design effectively improved ride comfort, handling stability, and driving safety. A rapid control prototype was built based on dSPACE to conduct a real vehicle test. The test and simulation results were consistent, which verified the simulation.

A Design Study of the Inflated Sphere Landing Vehicle, Including the Landing Performance and the Effects of Deviations from Design Conditions

NASA Technical Reports Server (NTRS)

Martin, E. Dale

1961-01-01

The impact motion of the inflated sphere landing vehicle with a payload centrally supported from the spherical skin by numerous cords has been determined on the assumption of uniform isentropic gas compression during impact. The landing capabilities are determined for a system containing suspension cords of constant cross section. The effects of deviations in impact velocity and initial gas temperature from the design conditions are studied. Also discussed are the effects of errors in the time at which the skin is ruptured. These studies indicate how the design parameters should be chosen to insure reliability of the landing system. Calculations have been made and results are presented for a sphere inflated with hydrogen, landing on the moon in the absence of an atmosphere. The results are presented for one value of the skin-strength parameter.

Chassis stabilization system

DOEpatents

Claxton, Gerald L.

1999-01-01

A stabilizing suspension system is provided for vehicles carrying telescopic booms or aerial work platforms having a fixed axle and a oscillating axle. Hydraulic cylinders are connected to each end of the oscillating axle, each cylinder being capable of extending and retracting. An off level sensor senses the angle of tilt of the chassis in both left and right directions and, when a predetermined threshold of tilt has been detected, the hydraulic cylinder on the downhill side of the chassis is locked against retracting, but is free to move in the downhill direction to allow the downhill wheel to remain in contact with the ground.

Lipid-based formulations for danazol containing a digestible surfactant, Labrafil M2125CS: in vivo bioavailability and dynamic in vitro lipolysis.

PubMed

Larsen, Anne; Holm, René; Pedersen, Mette Lund; Müllertz, Anette

2008-12-01

To evaluate the use of Labrafil M2125CS as a lipid vehicle for danazol. Further, the possibility of predicting the in vivo behavior with a dynamic in vitro lipolysis model was evaluated. Danazol (28 mg/kg) was administered orally to rats in four formulations: an aqueous suspension, two suspensions in Labrafil M2125CS (1 and 2 ml/kg) and a solution in Labrafil M2125CS (4 ml/kg). The obtained absolute bioavailabilities of danazol were 1.5 +/- 0.8%; 7.1 +/- 0.6%; 13.6 +/- 1.4% and 13.3 +/- 3.4% for the aqueous suspension, 1, 2 and 4 ml Labrafil M2125CS per kg respectively. Thus administration of danazol with Labrafil M2125CS resulted in up to a ninefold increase in the bioavailability, and the bioavailability was dependent on the Labrafil M2125CS dose. In vitro lipolysis of the formulations was able to predict the rank order of the bioavailability from the formulations, but not the absorption profile of the in vivo study. The bioavailability of danazol increased when Labrafil M2125CS was used as a vehicle, both when danazol was suspended and solubilized in the vehicle. The dynamic in vitro lipolysis model could be used to rank the bioavailabilities of the in vivo data.

Posture Report.

DTIC Science & Technology

1980-01-01

TON M871 22-1/2 Ton Semitrailer The M871 is a flatbed semitrailer, 30 feet long2- and 5 TON COMMERCIAL with tandem axle suspension, capable of TRUCK...It attenuates the peak blast impact im- SUSPENSION celerometers, developemnt of laminate stack pulses to the interior mounted equipment and bonding...and Carl .,nkley Patent No 4,180,599 issued 25 Dec 79 COMPOSITE LAMINATED VEHICLE ARMOR OF LASER SCANNER to Dr. Stephen M. Wolpert and Gustav J

Comparative analysis of the gene expression profile of probiotic Lactobacillus casei Zhang with and without fermented milk as a vehicle during transit in a simulated gastrointestinal tract.

PubMed

Wang, Jicheng; Zhong, Zhi; Zhang, Wenyi; Bao, Qiuhua; Wei, Aibin; Meng, He; Zhang, Heping

2012-06-01

Studies have found that the survival of probiotics could be strongly enhanced with dairy products as delivery vehicles, but the molecular mechanism by which this might occur has seldom been mentioned. In this study, microarray technology was used to detect the gene expression profile of Lactobacillus casei Zhang with and without fermented milk used as a delivery vehicle during transit in simulated gastrointestinal juice. Numerous genes of L. casei Zhang in strain suspension were upregulated compared to those from L. casei Zhang in fermented milk. These data might indicate that L. casei Zhang is stimulated directly without the protection of fermented milk, and the high-level gene expression observed here may be a stress response at the transcriptional level. A large proportion of genes involved in translation and cell division were downregulated in the bacteria that were in strain suspension during transit in simulated intestinal juice. This may impede protein biosynthesis and cell division and partially explain the lower viability of L. casei Zhang during transit in the gastrointestinal tract without the delivery vehicle. Copyright © 2012 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Effect of Seating on Exposures to Whole-Body Vibration in Vehicles

NASA Astrophysics Data System (ADS)

PADDAN, G. S.; GRIFFIN, M. J.

2002-05-01

The vibration isolation efficiency of seating has been evaluated in 100 work vehicles in 14 categories (cars, vans, lift trucks, lorries, tractors, buses, dumpers, excavators, helicopters, armoured vehicles, mobile cranes, grass rollers, mowers and milk floats). Seat isolation efficiency, expressed by the SEAT value, was determined for all seats (67 conventional seats and 33 suspension seats) from the vertical acceleration measured on the floors and on the seats of the vehicles.For most categories of vehicle, the average SEAT value was less than 100%, indicating that the average seat provided some attenuation of vibration. However, there were large variations in SEAT values between vehicles within categories. Two alternative vibration frequency weightings (Wb from BS 6841, 1987; Wk from ISO 2631, 1997) yielded SEAT values that differed by less than 6%. Overall, the SEAT values determined by two alternative methods (the ratio of r.m.s. values and the ratio of vibration dose values) differed by less than 4·5% when using weighting Wb, although larger differences may be expected in some situations. The median SEAT value for the suspension seats was 84·6%; the median SEAT value for the conventional seats was 86·9% (based on weighting Wb and the ratio of r.m.s. values).Predicted SEAT values were obtained assuming that each seat could be interchanged between vehicles without altering its transmissibility. The calculations suggest that 94% of the vehicles investigated might benefit from changing the current seat to a seat from one of the other vehicles investigated. Although the predictions are based on assumptions that will not always apply, it is concluded that the severity of whole-body vibration exposures in many work environments can be lessened by improvements to seating dynamics.

Intracerebral Cell Implantation: Preparation and Characterization of Cell Suspensions.

PubMed

Rossetti, Tiziana; Nicholls, Francesca; Modo, Michel

2016-01-01

Intracerebral cell transplantation is increasingly finding a clinical translation. However, the number of cells surviving after implantation is low (5-10%) compared to the number of cells injected. Although significant efforts have been made with regard to the investigation of apoptosis of cells after implantation, very little optimization of cell preparation and administration has been undertaken. Moreover, there is a general neglect of the biophysical aspects of cell injection. Cell transplantation can only be an efficient therapeutic approach if an optimal transfer of cells from the dish to the brain can be ensured. We therefore focused on the in vitro aspects of cell preparation of a clinical-grade human neural stem cell (NSC) line for intracerebral cell implantation. NSCs were suspended in five different vehicles: phosphate-buffered saline (PBS), Dulbecco's modified Eagle medium (DMEM), artificial cerebral spinal fluid (aCSF), HypoThermosol, and Pluronic. Suspension accuracy, consistency, and cell settling were determined for different cell volume fractions in addition to cell viability, cell membrane damage, and clumping. Maintenance of cells in suspension was evaluated while being stored for 8 h on ice, at room temperature, or physiological normothermia. Significant differences between suspension vehicles and cellular volume fractions were evident. HypoThermosol and Pluronic performed best, with PBS, aCSF, and DMEM exhibiting less consistency, especially in maintaining a suspension and preserving viability under different storage conditions. These results provide the basis to further investigate these preparation parameters during the intracerebral delivery of NSCs to provide an optimized delivery process that can ensure an efficient clinical translation.

Applications of magnetostrictive materials in the real-time monitoring of vehicle suspension components

NASA Astrophysics Data System (ADS)

Estrada, Raul

The purpose of this project is to explore applications of magnetostrictive materials for real-time monitoring of railroad suspension components, in particular bearings. Monitoring of such components typically requires the tracking of temperature vibration and load. In addition, real-time, long-term monitoring can be greatly facilitated through the use of wireless, self-powered sensors. Magnetostrictive materials, such as Terfenol-D, have the potential to address both requirements. Currently, piezoelectrics are used for many load and energy harvesting applications; however, they are fragile and are difficult to use for static load measurements. Magnetostrictive metals are tougher, and their property of variable permeability when stressed can be utilized to measure static loads. A prototype load sensor was successfully fabricated and characterized yielding less than 10% error under normal operating conditions. Energy harvesting experiments generated a little over 80 mW of power, which is sufficient to run low-power condition monitoring systems.

Influence of long-wavelength track irregularities on the motion of a high-speed train

NASA Astrophysics Data System (ADS)

Hung, C. F.; Hsu, W. L.

2018-01-01

Vertical track irregularities over viaducts in high-speed rail systems could be possibly caused by concrete creep if pre-stressed concrete bridges are used. For bridge spans that are almost uniformly distributed, track irregularity exhibits a near-regular wave profile that excites car bodies as a high-speed train moves over the bridge system. A long-wavelength irregularity induces low-frequency excitation that may be close to the natural frequencies of the train suspension system, thereby causing significant vibration of the car body. This paper investigates the relationship between the levels of car vibration, bridge vibration, track irregularity, and the train speed. First, this study investigates the vibration levels of a high-speed train and bridge system using 3D finite-element (FE) transient dynamic analysis, before and after adjustment of vertical track irregularities by means of installing shimming plates under rail pads. The analysis models are validated by in situ measurements and on-board measurement. Parametric studies of car body vibration and bridge vibration under three different levels of track irregularity at five train speeds and over two bridge span lengths are conducted using the FE model. Finally, a discontinuous shimming pattern is proposed to avoid vehicle suspension resonance.

Chemical stability of extemporaneously prepared Lorazepam suspension at two temperatures.

PubMed

Lee, Wan-Man Ellaria; Lugo, Ralph A; Rusho, William J; Mackay, Mark; Sweeley, John

2004-10-01

The objective of this study was to determine the chemical stability of extemporaneously prepared lorazepam suspension (1 mg/mL) stored at two temperatures (4°C and 22°C) for 3 months. Lorazepam tablets marketed by two manufacturers (Mylan Pharmaceuticals and Watson Laboratories) were used to extemporaneously formulate two independently prepared suspensions. Each suspension was prepared using sterile water, Ora-Plus(®) and Ora-Sweet(®) to achieve a final concentration of 1 mg/mL. The two brands of tablets required different volumes of vehicles to prepare a pharmaceutically optimal suspension. The suspensions were stored in amber glass bottles at 4°C and 22°C for 91 days. Samples were analyzed by high performance liquid chromatography at baseline and on days 2, 3, 7, 14, 21, 28, 42, 63, and 91. The suspensions were considered stable if the mean lorazepam concentration remained greater than 90% of the initial concentration.The chemical stabilities of these two extemporaneously prepared lorazepam suspensions were comparable throughout the study. Both lorazepam suspensions were stable for 63 days when stored at 4°C or 22°C, and both were stable for 91 days when refrigerated at 4°C. When stored at room temperature, the suspension prepared from the Watson tablet retained 88.9 ± 1.4% of the initial concentration on day 91 and was therefore considered unstable, while the suspension prepared from the Mylan tablet was stable for the entire 91-day study.

Application of optimization techniques to vehicle design: A review

NASA Technical Reports Server (NTRS)

Prasad, B.; Magee, C. L.

1984-01-01

The work that has been done in the last decade or so in the application of optimization techniques to vehicle design is discussed. Much of the work reviewed deals with the design of body or suspension (chassis) components for reduced weight. Also reviewed are studies dealing with system optimization problems for improved functional performance, such as ride or handling. In reviewing the work on the use of optimization techniques, one notes the transition from the rare mention of the methods in the 70's to an increased effort in the early 80's. Efficient and convenient optimization and analysis tools still need to be developed so that they can be regularly applied in the early design stage of the vehicle development cycle to be most effective. Based on the reported applications, an attempt is made to assess the potential for automotive application of optimization techniques. The major issue involved remains the creation of quantifiable means of analysis to be used in vehicle design. The conventional process of vehicle design still contains much experience-based input because it has not yet proven possible to quantify all important constraints. This restraint on the part of the analysis will continue to be a major limiting factor in application of optimization to vehicle design.

Design and analysis of automobile components using industrial procedures

NASA Astrophysics Data System (ADS)

Kedar, B.; Ashok, B.; Rastogi, Nisha; Shetty, Siddhanth

2017-11-01

Today’s automobiles depend upon mechanical systems that are crucial for aiding in the movement and safety features of the vehicle. Various safety systems such as Antilock Braking System (ABS) and passenger restraint systems have been developed to ensure that in the event of a collision be it head on or any other type, the safety of the passenger is ensured. On the other side, manufacturers also want their customers to have a good experience while driving and thus aim to improve the handling and the drivability of the vehicle. Electronics systems such as Cruise Control and active suspension systems are designed to ensure passenger comfort. Finally, to ensure optimum and safe driving the various components of a vehicle must be manufactured using the latest state of the art processes and must be tested and inspected with utmost care so that any defective component can be prevented from being sent out right at the beginning of the supply chain. Therefore, processes which can improve the lifetime of their respective components are in high demand and much research and development is done on these processes. With a solid base research conducted, these processes can be used in a much more versatile manner for different components, made up of different materials and under different input conditions. This will help increase the profitability of the process and also upgrade its value to the industry.

The effect of polymer content on the non-newtonian behavior of acetaminophen suspension.

PubMed

Moghimipour, Eskandar; Kouchak, Maryam; Salimi, Anayatollah; Bahrampour, Saeed; Handali, Somayeh

2013-01-01

Acetaminophen is used as an analgesic and antipyretic agent. The aim of the study was evaluation of the effect of different polymers on rheological behavior of acetaminophen suspension. In order to achieve controlled flocculation, sodium chloride was added. Then structural vehicles such as carboxymethyl cellulose (CMC), polyvinyl pyrrolidone (PVP), tragacanth, and magnesium aluminum silicate (Veegum) were evaluated individually and in combination. Physical stability parameters such as sedimentation volume (F), redispersibility (n), and growth of crystals of the suspensions were determined. Also, the rheological properties of formulations were studied. The results of this study showed that the combination of suspending agents had the most physical stability and pseudoplastic behavior with some degree of thixotropy. Viscosity of suspensions was increased by adding NaCl 0.02%. Presence of PVP is necessary for improving rheological behavior of suspensions by NaCl. This may be related to the cross-linking between the carbonyl group in the PVP segment and Na(+) ions.

The Effect of Polymer Content on the Non-Newtonian Behavior of Acetaminophen Suspension

PubMed Central

Moghimipour, Eskandar; Kouchak, Maryam; Salimi, Anayatollah; Bahrampour, Saeed; Handali, Somayeh

2013-01-01

Acetaminophen is used as an analgesic and antipyretic agent. The aim of the study was evaluation of the effect of different polymers on rheological behavior of acetaminophen suspension. In order to achieve controlled flocculation, sodium chloride was added. Then structural vehicles such as carboxymethyl cellulose (CMC), polyvinyl pyrrolidone (PVP), tragacanth, and magnesium aluminum silicate (Veegum) were evaluated individually and in combination. Physical stability parameters such as sedimentation volume (F), redispersibility (n), and growth of crystals of the suspensions were determined. Also, the rheological properties of formulations were studied. The results of this study showed that the combination of suspending agents had the most physical stability and pseudoplastic behavior with some degree of thixotropy. Viscosity of suspensions was increased by adding NaCl 0.02%. Presence of PVP is necessary for improving rheological behavior of suspensions by NaCl. This may be related to the cross-linking between the carbonyl group in the PVP segment and Na+ ions. PMID:24109512

21 CFR 522.1451 - Moxidectin for suspension.

Code of Federal Regulations, 2010 CFR

2010-04-01

.... One contains 10 percent moxidectin microspheres, and the other contains a vehicle for constitution of... stenocephala infections. (3) Limitations. Federal law restricts this drug to use by or on the order of a...

21 CFR 522.1451 - Moxidectin for suspension.

Code of Federal Regulations, 2012 CFR

2012-04-01

.... One contains 10 percent moxidectin microspheres, and the other contains a vehicle for constitution of... stenocephala infections. (3) Limitations. Federal law restricts this drug to use by or on the order of a...

21 CFR 522.1451 - Moxidectin for suspension.

Code of Federal Regulations, 2011 CFR

2011-04-01

.... One contains 10 percent moxidectin microspheres, and the other contains a vehicle for constitution of... stenocephala infections. (3) Limitations. Federal law restricts this drug to use by or on the order of a...

Machine learning from computer simulations with applications in rail vehicle dynamics

NASA Astrophysics Data System (ADS)

Taheri, Mehdi; Ahmadian, Mehdi

2016-05-01

The application of stochastic modelling for learning the behaviour of a multibody dynamics (MBD) models is investigated. Post-processing data from a simulation run are used to train the stochastic model that estimates the relationship between model inputs (suspension relative displacement and velocity) and the output (sum of suspension forces). The stochastic model can be used to reduce the computational burden of the MBD model by replacing a computationally expensive subsystem in the model (suspension subsystem). With minor changes, the stochastic modelling technique is able to learn the behaviour of a physical system and integrate its behaviour within MBD models. The technique is highly advantageous for MBD models where real-time simulations are necessary, or with models that have a large number of repeated substructures, e.g. modelling a train with a large number of railcars. The fact that the training data are acquired prior to the development of the stochastic model discards the conventional sampling plan strategies like Latin Hypercube sampling plans where simulations are performed using the inputs dictated by the sampling plan. Since the sampling plan greatly influences the overall accuracy and efficiency of the stochastic predictions, a sampling plan suitable for the process is developed where the most space-filling subset of the acquired data with ? number of sample points that best describes the dynamic behaviour of the system under study is selected as the training data.

Determination of ASPS performance for large payloads in the shuttle orbiter disturbance environment. [digital simulation

NASA Technical Reports Server (NTRS)

Keckler, C. R.; Kibler, K. S.; Powell, L. F.

1979-01-01

A high fidelity simulation of the annular suspension and pointing system (ASPS), its payload, and the shuttle orbiter was used to define the worst case orientations of the ASPS and its payload for the various vehicle disturbances, and to determine the performance capability of the ASPS under these conditions. The most demanding and largest proposed payload, the Solar Optical Telescope was selected for study. It was found that, in all cases, the ASPS more than satisfied the payload's requirements. It is concluded that, to satisfy facility class payload requirements, the ASPS or a shuttle orbiter free-drift mode (control system off) should be utilized.

Effect of temperature- and frequency-dependent dynamic properties of rail pads on high-speed vehicle-track coupled vibrations

NASA Astrophysics Data System (ADS)

Wei, Kai; Wang, Feng; Wang, Ping; Liu, Zi-xuan; Zhang, Pan

2017-03-01

The soft under baseplate pad of WJ-8 rail fastener frequently used in China's high-speed railways was taken as the study subject, and a laboratory test was performed to measure its temperature and frequency-dependent dynamic performance at 0.3 Hz and at -60°C to 20°C with intervals of 2.5°C. Its higher frequency-dependent results at different temperatures were then further predicted based on the time-temperature superposition (TTS) and Williams-Landel-Ferry (WLF) formula. The fractional derivative Kelvin-Voigt (FDKV) model was used to represent the temperature- and frequency-dependent dynamic properties of the tested rail pad. By means of the FDKV model for rail pads and vehicle-track coupled dynamic theory, high-speed vehicle-track coupled vibrations due to temperature- and frequency-dependent dynamic properties of rail pads was investigated. Finally, further combining with the measured frequency-dependent dynamic performance of vehicle's rubber primary suspension, the high-speed vehicle-track coupled vibration responses were discussed. It is found that the storage stiffness and loss factor of the tested rail pad are sensitive to low temperatures or high frequencies. The proposed FDKV model for the frequency-dependent storage stiffness and loss factors of the tested rail pad can basically meet the fitting precision, especially at ordinary temperatures. The numerical simulation results indicate that the vertical vibration levels of high-speed vehicle-track coupled systems calculated with the FDKV model for rail pads in time domain are higher than those calculated with the ordinary Kelvin-Voigt (KV) model for rail pads. Additionally, the temperature- and frequency-dependent dynamic properties of the tested rail pads would alter the vertical vibration acceleration levels (VALs) of the car body and bogie in 1/3 octave frequencies above 31.5 Hz, especially enlarge the vertical VALs of the wheel set and rail in 1/3 octave frequencies of 31.5-100 Hz and above 315 Hz, which are the dominant frequencies of ground vibration acceleration and rolling noise (or bridge noise) caused by high-speed railways respectively. Since the fractional derivative value of the adopted rubber primary suspension, unlike the tested rail pad, is very close to 1, its frequency-dependent dynamic performance has little effect on high-speed vehicle-track coupled vibration responses.

Integration of regenerative shock absorber into vehicle electric system

NASA Astrophysics Data System (ADS)

Zhang, Chongxiao; Li, Peng; Xing, Shaoxu; Kim, Junyoung; Yu, Liangyao; Zuo, Lei

2014-03-01

Regenerative/Energy harvesting shock absorbers have a great potential to increase fuel efficiency and provide suspension damping simultaneously. In recent years there's intensive work on this topic, but most researches focus on electricity extraction from vibration and harvesting efficiency improvement. The integration of electricity generated from regenerative shock absorbers into vehicle electric system, which is very important to realize the fuel efficiency benefit, has not been investigated. This paper is to study and demonstrate the integration of regenerative shock absorber with vehicle alternator, battery and in-vehicle electrical load together. In the presented system, the shock absorber is excited by a shaker and it converts kinetic energy into electricity. The harvested electricity flows into a DC/DC converter which realizes two functions: controlling the shock absorber's damping and regulating the output voltage. The damping is tuned by controlling shock absorber's output current, which is also the input current of DC/DC converter. By adjusting the duty cycles of switches in the converter, its input impedance together with input current can be adjusted according to dynamic damping requirements. An automotive lead-acid battery is charged by the DC/DC converter's output. To simulate the working condition of combustion engine, an AC motor is used to drive a truck alternator, which also charges the battery. Power resistors are used as battery's electrical load to simulate in-vehicle electrical devices. Experimental results show that the proposed integration strategy can effectively utilize the harvested electricity and power consumption of the AC motor is decreased accordingly. This proves the combustion engine's load reduction and fuel efficiency improvement.

Motion estimation by integrated low cost system (vision and MEMS) for positioning of a scooter "Vespa"

NASA Astrophysics Data System (ADS)

Guarnieri, A.; Milan, N.; Pirotti, F.; Vettore, A.

2011-12-01

In the automotive sector, especially in these last decade, a growing number of investigations have taken into account electronic systems to check and correct the behavior of drivers, increasing road safety. The possibility to identify with high accuracy the vehicle position in a mapping reference frame for driving directions and best-route analysis is also another topic which attracts lot of interest from the research and development sector. To reach the objective of accurate vehicle positioning and integrate response events, it is necessary to estimate time by time the position, orientation and velocity of the system. To this aim low cost GPS and MEMS (sensors can be used. In comparison to a four wheel vehicle, the dynamics of a two wheel vehicle (e.g. a scooter) feature a higher level of complexity. Indeed more degrees of freedom must be taken into account to describe the motion of the latter. For example a scooter can twist sideways, thus generating a roll angle. A slight pitch angle has to be considered as well, since wheel suspensions have a higher degree of motion with respect to four wheel vehicles. In this paper we present a method for the accurate reconstruction of the trajectory of a motorcycle ("Vespa" scooter), which can be used as alternative to the "classical" approach based on the integration of GPS and INS sensors. Position and orientation of the scooter are derived from MEMS data and images acquired by on-board digital camera. A Bayesian filter provides the means for integrating the data from MEMS-based orientation sensor and the GPS receiver.

Suspension parameter estimation in the frequency domain using a matrix inversion approach

NASA Astrophysics Data System (ADS)

Thite, A. N.; Banvidi, S.; Ibicek, T.; Bennett, L.

2011-12-01

The dynamic lumped parameter models used to optimise the ride and handling of a vehicle require base values of the suspension parameters. These parameters are generally experimentally identified. The accuracy of identified parameters can depend on the measurement noise and the validity of the model used. The existing publications on suspension parameter identification are generally based on the time domain and use a limited degree of freedom. Further, the data used are either from a simulated 'experiment' or from a laboratory test on an idealised quarter or a half-car model. In this paper, a method is developed in the frequency domain which effectively accounts for the measurement noise. Additional dynamic constraining equations are incorporated and the proposed formulation results in a matrix inversion approach. The nonlinearities in damping are estimated, however, using a time-domain approach. Full-scale 4-post rig test data of a vehicle are used. The variations in the results are discussed using the modal resonant behaviour. Further, a method is implemented to show how the results can be improved when the matrix inverted is ill-conditioned. The case study shows a good agreement between the estimates based on the proposed frequency-domain approach and measurable physical parameters.

Digital control analysis and design of a field-sensed magnetic suspension system.

PubMed

Li, Jen-Hsing; Chiou, Juing-Shian

2015-03-13

Magnetic suspension systems are mechatronic systems and crucial in several engineering applications, such as the levitation of high-speed trains, frictionless bearings, and wind tunnels. Magnetic suspension systems are nonlinear and unstable systems; therefore, they are suitable educational benchmarks for testing various modeling and control methods. This paper presents the digital modeling and control of magnetic suspension systems. First, the magnetic suspension system is stabilized using a digital proportional-derivative controller. Subsequently, the digital model is identified using recursive algorithms. Finally, a digital mixed linear quadratic regulator (LQR)/H∞ control is adopted to stabilize the magnetic suspension system robustly. Simulation examples and a real-world example are provided to demonstrate the practicality of the study results. In this study, a digital magnetic suspension system model was developed and reviewed. In addition, equivalent state and output feedback controls for magnetic suspension systems were developed. Using this method, the controller design for magnetic suspension systems was simplified, which is the novel contribution of this study. In addition, this paper proposes a complete digital controller design procedure for magnetic suspension systems.

40 CFR 86.612-97 - Suspension and revocation of certificates of conformity.

Code of Federal Regulations, 2010 CFR

2010-07-01

... ENGINES (CONTINUED) Selective Enforcement Auditing of New Light-Duty Vehicles, Light-Duty Trucks, and... control and/or quality assurance measures to be taken by the manufacturer to prevent the future occurrence...

Stability of Extemporaneously Prepared Hydroxychloroquine Sulfate 25-mg/mL Suspensions in Plastic Bottles and Syringes.

PubMed

McHenry, Adam R; Wempe, Michael F; Rice, Peter J

2017-01-01

This study evaluated the stability of the antimalarial and anti-rheumatic drug hydroxychloroquine sulfate in two commercially available suspension vehicles, Oral Mix and Oral Mix SF (Medisca Pharmaceutique Inc.). Hydroxychloroquine sulfate (25 mg/mL) suspension was prepared, packaged in amber 50-mL polyethylene terephthalate bottles and amber 3-mL syringes, and stored at room temperature or at 4°C. Samples were collected and analyzed over a 16-week period by high-performance liquid chromatography with ultraviolet detection at 340 nm. Approximately 99.8% of the hydroxychloroquine remained at the conclusion of the study, with no observable difference between room temperature and refrigerated storage. Hydroxychloroquine sulfate is stable for at least 90 days in Medisca Oral Mix or Oral Mix SF suspension media at 25°C and 4°C. Copyright© by International Journal of Pharmaceutical Compounding, Inc.

Photosensitized degradation of losartan potassium in an extemporaneous suspension formulation.

PubMed

Seburg, Randal A; Ballard, John M; Hwang, Tsang-Lin; Sullivan, Caitlin M

2006-10-11

During development of an extemporaneous suspension formulation for losartan potassium, previously unknown degradation products were observed in experimental suspensions prepared in a commercial cherry syrup vehicle. These degradates increased rapidly when analytical solutions prepared from that suspension were exposed to ambient light. The structures of the degradates were determined using a combination of preparative HPLC, LC/MS, (13)C and (1)H NMR (1D and 2D), and mechanistic chemistry. Each degradate results from destruction of the imidazole ring of losartan. Formation of the two major degradates required exposure to light (UV or visible) and the presence of oxygen. Experiments using Rose Bengal (a singlet oxygen photosensitizer) and 1,4-diazabicyclooctane (DABCO; a singlet oxygen quencher) established that the major photodegradates are formed via the intermediacy of singlet oxygen. The identity of the photosensitizer in the formulation was not unequivocally determined; however, the experiments implicated the artificial flavoring in fulfilling this role.

Optimization analysis of a new vane MRF damper

NASA Astrophysics Data System (ADS)

Zhang, J. Q.; Feng, Z. Z.; Jing, Q.

2009-02-01

The primary purpose of this study was to provide the optimization analysis certain characteristics and benefits of a vane MRF damper. Based on the structure of conventional vane hydraulic damper for heavy vehicle, a narrow arc gap between clapboard and rotary vane axle, which one rotates relative to the other, was designed for MRF valve and the mathematical model of damping was deduced. Subsequently, the finite element analysis of electromagnetic circuit was done by ANSYS to perform the optimization process. Some ways were presented to augment the damping adjustable multiple under the condition of keeping initial damping forces and to increase fluid dwell time through the magnetic field. The results show that the method is useful in the design of MR dampers and the damping adjustable range of vane MRF damper can meet the requirement of heavy vehicle semi-active suspension system.

Microgels produced using microfluidic on-chip polymer blending for controlled released of VEGF encoding lentivectors.

PubMed

Madrigal, Justin L; Sharma, Shonit N; Campbell, Kevin T; Stilhano, Roberta S; Gijsbers, Rik; Silva, Eduardo A

2018-03-15

Alginate hydrogels are widely used as delivery vehicles due to their ability to encapsulate and release a wide range of cargos in a gentle and biocompatible manner. The release of encapsulated therapeutic cargos can be promoted or stunted by adjusting the hydrogel physiochemical properties. However, the release from such systems is often skewed towards burst-release or lengthy retention. To address this, we hypothesized that the overall magnitude of burst release could be adjusted by combining microgels with distinct properties and release behavior. Microgel suspensions were generated using a process we have termed on-chip polymer blending to yield composite suspensions of a range of microgel formulations. In this manner, we studied how alginate percentage and degradation relate to the release of lentivectors. Whereas changes in alginate percentage had a minimal impact on lentivector release, microgel degradation led to a 3-fold increase, and near complete release, over 10 days. Furthermore, by controlling the amount of degradable alginate present within microgels the relative rate of release can be adjusted. A degradable formulation of microgels was used to deliver vascular endothelial growth factor (VEGF)-encoding lentivectors in the chick chorioallantoic membrane (CAM) assay and yielded a proangiogenic response in comparison to the same lentivectors delivered in suspension. The utility of blended microgel suspensions may provide an especially appealing platform for the delivery of lentivectors or similarly sized therapeutics. Genetic therapeutics hold considerable potential for the treatment of diseases and disorders including ischemic cardiovascular diseases. To realize this potential, genetic vectors must be precisely and efficiently delivered to targeted regions of the body. However, conventional methods of delivery do not provide sufficient spatial and temporal control. Here, we demonstrate how alginate microgels provide a basis for developing systems for controlled genetic vector release. We adjust the physiochemical properties of alginate for quicker or slower release, and we demonstrate how combining distinct formulations of microgels can tune the release of the overall composite microgel suspension. These composite suspensions are generated using a straightforward and powerful application of droplet microfluidics which allows for the real-time generation of a composite suspension. Copyright © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Randomized, Controlled, Phase 2 Trial of Povidone-Iodine/Dexamethasone Ophthalmic Suspension for Treatment of Adenoviral Conjunctivitis.

PubMed

Pepose, Jay S; Ahuja, Arjun; Liu, Wenlei; Narvekar, Abhijit; Haque, Reza

2018-05-19

To evaluate the efficacy/safety of an ophthalmic suspension of povidone-iodine (PVP-I) 0.6% and dexamethasone 0.1% in patients with acute adenoviral conjunctivitis. Multicenter, randomized, vehicle-controlled, double-masked trial. Adults with a positive Rapid Pathogen Screening Adeno-Detector Plus TM test were randomized 1:1:1 to PVP-I 0.6%/dexamethasone 0.1%, PVP-I 0.6%, or vehicle, bilaterally 4 times daily for 5 days (days 1-5). Patients were evaluated on days 3, 6, and 12 (+1-day window). Efficacy measures included clinical resolution and adenoviral eradication. Overall, 144 patients were included in the efficacy analysis (PVP-I/dexamethasone, n = 48; PVP-I, n = 50; vehicle, n = 46). The proportion of patients with clinical resolution (primary study eye with last observation carried forward [LOCF]) at the day 6 visit was higher with PVP-I/dexamethasone (31.3%) than vehicle (10.9%; P = .0158) and PVP-I (18.0%; P = nonsignificant). The proportion with adenoviral eradication (primary study eye with LOCF) was higher with PVP-I/dexamethasone than vehicle at the day 3 (35.4% vs 8.7%; P = .0019) and day 6 (79.2% vs 56.5%; P = .0186) visits and versus PVP-I (day 3 visit, 32.0%; day 6 visit, 62.0%; each P = nonsignificant). Treatment-emergent adverse events (AEs) occurred in 69.0% (vehicle), 62.7% (PVP-I), and 53.4% (PVP-I/dexamethasone) of patients in the safety dataset. Discontinuation owing to AEs occurred in 37 patients (vehicle, n = 16; PVP-I, n = 12; PVP-I/dexamethasone, n = 9). PVP-I/dexamethasone appeared safe and well tolerated, and significantly improved clinical resolution and adenoviral eradication in patients with acute adenoviral conjunctivitis. Copyright © 2018. Published by Elsevier Inc.

Stability and compatibility of tegaserod from crushed tablets mixed in beverages and foods.

PubMed

Carrier, Marie-Noëlle; Garinot, Olivier; Vitzling, Christian

2004-06-01

The stability and compatibility of tegaserod from crushed tablets in selected beverages and foods were studied. Suspensions of tegaserod maleate tablets containing 6 mg of the drug base were prepared by crushing the tablets and mixing the powder with tap water, apple juice, orange juice, milk, applesauce, yogurt, and chocolate-hazelnut spread. Drug stability, drug comparability, suspension homogeneity, and completeness of a dose were measured by high-performance liquid chromatography at intervals up to three days at 20-25 degrees C and 5 degrees C. In vitro dissolution profiles were determined for crushed tegaserod tablets in water, apple juice, orange juice, and applesauce. Tegaserod from crushed tablets was stable in and compatible with water, apple juice, orange juice, and applesauce, and the suspensions were homogeneous. The complete dose was delivered with these media. The dissolution profiles of crushed tegaserod tablets in water and in apple juice were comparable to those of intact tablets; the dissolution profiles in orange juice and applesauce were not comparable with those of intact tablets. The results with milk, yogurt, and chocolate-hazelnut spread as vehicles were inconclusive. The suspension in milk was not homogeneous, and the dose was incomplete. Tegaserod from crushed tablets was stable in and compatible with water, apple juice, orange juice, and applesauce, but the dissolution profile in orange juice or applesauce was not acceptable. Apple juice may be the preferred vehicle because it masks the drug's taste.

Fabrication and experimentation of FRP helical spring

NASA Astrophysics Data System (ADS)

Ekanthappa, J.; Shiva Shankar, G. S.; Amith, B. M.; Gagan, M.

2016-09-01

In present scenario, the automobile industry sector is showing increased interest in reducing the unsprung weight of the automobile & hence increasing the fuel Efficiency. One of the feasible sub systems of a vehicle where weight reduction may be attempted is vehicle- suspension system. Usage of composite material is a proven way to lower the component weight without any compromise in strength. The composite materials are having high specific strength, more elastic strain energy storage capacity in comparison with those of steel. Therefore, helical coil spring made of steel is replaceable by composite cylindrical helical coil spring. This research aims at preparing a re-usable mandrel (mould) of Mild steel, developing a setup for fabrication, fabrication of FRP helical spring using continuous glass fibers and Epoxy Resin (Polymer). Experimentation has been conducted on fabricated FRP helical spring to determine its strength parameters & for failure analysis. It is found that spring stiffness (K) of Glass/Epoxy helical-spring is greater than steel-coil spring with reduced weight.

Stability of gabapentin in extemporaneously compounded oral suspensions.

PubMed

Friciu, Mihaela; Roullin, V Gaëlle; Leclair, Grégoire

2017-01-01

This study reports the stability of extemporaneously prepared gabapentin oral suspensions prepared at 100 mg/mL from bulk drug and capsules in either Oral Mix or Oral Mix SF suspending vehicles. Suspensions were packaged in amber plastic bottles and amber plastic syringes at 25°C / 60%RH for up to 90 days. Throughout the study period, the following tests were performed to evaluate the stability of the preparations: organoleptic inspection to detect homogeneity, color or odor changes; pH measurements; and gabapentin assay using a stability-indicating HPLC-UV method. As crystallization was observed at 5°C, storage at this temperature condition is not recommended. All preparations stored at 25°C / 60%RH remained stable for the whole study duration of 90 days.

Stability of oseltamivir in various extemporaneous liquid preparations.

PubMed

Ford, Stephen M; Kloesel, Lawson G; Grabenstein, John D

2007-01-01

The purpose of this study was to determine the stability of oseltamivir, the active ingredient in Tamiflu, in contemporaneously compounded suspensions for a period of not less than 90 days. The suspension vehicles provided for the study were chosen because of ease of preparation, commercial availability, and palatability. Stability of the active ingredient was demonstrated for suspensions prepared in PCCA-Plus, PCCA Acacia, and 1% methylcellulose and was independent of storage temperature (tested temperatures were 2 deg C to 8 deg C and 25 deg C). A control sample of the commercial liquid form of Tamiflu was prepared, stored and analyzed along with the samples prepared from the contents of capsules. There was no difference in the apparent stability of the two forms of the drug preparation.

Vehicle dynamic analysis using neuronal network algorithms

NASA Astrophysics Data System (ADS)

Oloeriu, Florin; Mocian, Oana

2014-06-01

Theoretical developments of certain engineering areas, the emergence of new investigation tools, which are better and more precise and their implementation on-board the everyday vehicles, all these represent main influence factors that impact the theoretical and experimental study of vehicle's dynamic behavior. Once the implementation of these new technologies onto the vehicle's construction had been achieved, it had led to more and more complex systems. Some of the most important, such as the electronic control of engine, transmission, suspension, steering, braking and traction had a positive impact onto the vehicle's dynamic behavior. The existence of CPU on-board vehicles allows data acquisition and storage and it leads to a more accurate and better experimental and theoretical study of vehicle dynamics. It uses the information offered directly by the already on-board built-in elements of electronic control systems. The technical literature that studies vehicle dynamics is entirely focused onto parametric analysis. This kind of approach adopts two simplifying assumptions. Functional parameters obey certain distribution laws, which are known in classical statistics theory. The second assumption states that the mathematical models are previously known and have coefficients that are not time-dependent. Both the mentioned assumptions are not confirmed in real situations: the functional parameters do not follow any known statistical repartition laws and the mathematical laws aren't previously known and contain families of parameters and are mostly time-dependent. The purpose of the paper is to present a more accurate analysis methodology that can be applied when studying vehicle's dynamic behavior. A method that provides the setting of non-parametrical mathematical models for vehicle's dynamic behavior is relying on neuronal networks. This method contains coefficients that are time-dependent. Neuronal networks are mostly used in various types' system controls, thus being a non-linear process identification algorithm. The common use of neuronal networks for non-linear processes is justified by the fact that both have the ability to organize by themselves. That is why the neuronal networks best define intelligent systems, thus the word `neuronal' is sending one's mind to the biological neuron cell. The paper presents how to better interpret data fed from the on-board computer and a new way of processing that data to better model the real life dynamic behavior of the vehicle.

Preservative-free triamcinolone acetonide suspension developed for intravitreal injection.

PubMed

Bitter, Christoph; Suter, Katja; Figueiredo, Verena; Pruente, Christian; Hatz, Katja; Surber, Christian

2008-02-01

All commercially available triamcinolone acetonide (TACA) suspensions, used for intravitreal treatment, contain retinal toxic vehicles (e.g., benzyl alcohol, solubilizer). Our aim was to find a convenient and reproducible method to compound a completely preservative-free TACA suspension, adapted to the intraocular physiology, with consistent quality (i.e., proven sterility and stability, constant content and dose uniformity, defined particle size, and 1 year shelf life). We evaluated two published (Membrane-filter, Centrifugation) and a newly developed method (Direct Suspending) to compound TACA suspensions for intravitreal injection. Parameters as TACA content (HPLC), particle size (microscopy and laser spectrometry), sterility, and bacterial endotoxins were assessed. Stability testing (at room temperature and 40 degrees C) was performed: color and homogeneity (visually), particle size (microscopically), TACA content and dose uniformity (HPLC) were analyzed according to International Conference on Harmonisation guidelines. Contrary to the known methods, the direct suspending method is convenient, provides a TACA suspension, which fulfills all compendial requirements, and has a 2-year shelf life. We developed a simple, reproducible method to compound stable, completely preservative-free TACA suspensions with a reasonable shelf-life, which enables to study the effect of intravitreal TACA--not biased by varying doses and toxic compounds or their residues.

40 CFR 86.442-78 - Denial, revocation, or suspension of certification.

Code of Federal Regulations, 2010 CFR

2010-07-01

... ab initio. (d) In any case in which certification of a vehicle is proposed to be withheld, denied... fraud or other misconduct as makes the certification invalid ab initio. (f) The manufacturer may request...

40 CFR 86.442-78 - Denial, revocation, or suspension of certification.

Code of Federal Regulations, 2014 CFR

2014-07-01

... ab initio. (d) In any case in which certification of a vehicle is proposed to be withheld, denied... fraud or other misconduct as makes the certification invalid ab initio. (f) The manufacturer may request...

40 CFR 86.442-78 - Denial, revocation, or suspension of certification.

Code of Federal Regulations, 2012 CFR

2012-07-01

... ab initio. (d) In any case in which certification of a vehicle is proposed to be withheld, denied... fraud or other misconduct as makes the certification invalid ab initio. (f) The manufacturer may request...

40 CFR 86.442-78 - Denial, revocation, or suspension of certification.

Code of Federal Regulations, 2013 CFR

2013-07-01

... ab initio. (d) In any case in which certification of a vehicle is proposed to be withheld, denied... fraud or other misconduct as makes the certification invalid ab initio. (f) The manufacturer may request...

40 CFR 86.442-78 - Denial, revocation, or suspension of certification.

Code of Federal Regulations, 2011 CFR

2011-07-01

... ab initio. (d) In any case in which certification of a vehicle is proposed to be withheld, denied... fraud or other misconduct as makes the certification invalid ab initio. (f) The manufacturer may request...

Administration of Substances to Laboratory Animals: Equipment Considerations, Vehicle Selection, and Solute Preparation

PubMed Central

Turner, Patricia V; Pekow, Cynthia; Vasbinder, Mary Ann; Brabb, Thea

2011-01-01

Administration of substances to laboratory animals requires careful consideration and planning to optimize delivery of the agent to the animal while minimizing potential adverse experiences from the procedure. The equipment selected to deliver substances to animals depends on the length of the study and the nature of the material being administered. This selection provides a significant opportunity for refining animal treatment. Similarly, when substances are administered as solutions or suspensions, attention should be given to selection of vehicles and methods used for preparing the solutions and suspensions. The research team, veterinarian, technical personnel, and IACUC members should be aware of reasons underlying selection of equipment for substance delivery and should consider carefully how substances will be prepared and stored prior to administration to animals. Failure to consider these factors during experimental planning may result in unintentional adverse effects on experimental animals and confounded results. PMID:22330706

Gait Biomechanics of Individuals with Transtibial Amputation: Effect of Suspension System

PubMed Central

Eshraghi, Arezoo; Abu Osman, Noor Azuan; Karimi, Mohammad; Gholizadeh, Hossein; Soodmand, Ehsan; Abas, Wan Abu Bakar Wan

2014-01-01

Prosthetic suspension system is an important component of lower limb prostheses. Suspension efficiency can be best evaluated during one of the vital activities of daily living, i.e. walking. A new magnetic prosthetic suspension system has been developed, but its effects on gait biomechanics have not been studied. This study aimed to explore the effect of suspension type on kinetic and kinematic gait parameters during level walking with the new suspension system as well as two other commonly used systems (the Seal-In and pin/lock). Thirteen persons with transtibial amputation participated in this study. A Vicon motion system (six cameras, two force platforms) was utilized to obtain gait kinetic and kinematic variables, as well as pistoning within the prosthetic socket. The gait deviation index was also calculated based on the kinematic data. The findings indicated significant difference in the pistoning values among the three suspension systems. The Seal-In system resulted in the least pistoning compared with the other two systems. Several kinetic and kinematic variables were also affected by the suspension type. The ground reaction force data showed that lower load was applied to the limb joints with the magnetic suspension system compared with the pin/lock suspension. The gait deviation index showed significant deviation from the normal with all the systems, but the systems did not differ significantly. Main significant effects of the suspension type were seen in the GRF (vertical and fore-aft), knee and ankle angles. The new magnetic suspension system showed comparable effects in the remaining kinetic and kinematic gait parameters to the other studied systems. This study may have implications on the selection of suspension systems for transtibial prostheses. Trial Registration Iranian Registry of Clinical Trials IRCT2013061813706N1. PMID:24865351

Compact, Isolating Elastomeric Suspension for Vehicle Acoustic Vector Sensor

DTIC Science & Technology

2007-09-30

well as underwater acoustics. His Master’s thesis, funded by NUSC, was a study of near-body acoustic signal behavior entitled “Some Characteristics of ...in non-polymer based composites, including cermets . He has formulated a very wide range of materials for an equally wide range of applications, and...with a moving vehicle of an instrument responsive to particle accelerations in the surrounding medium. The overall goal of this project is to develop

Stair-climbing capabilities of USU's T3 ODV mobile robot

NASA Astrophysics Data System (ADS)

Robinson, D. Reed; Wood, Carl G.

2001-09-01

A six-wheeled autonomous omni-directional vehicle (ODV) called T3 has been developed at Utah State University's (USU) Center for Self-Organizing and Intelligent Systems (CSOIS). This paper focuses on T3's ability to climb stairs using its unique configuration of 6 independently driven and steered wheels and active suspension height control. The ability of T3, or any similar vehicle, to climb stairs is greatly dependent on the chassis orientation relative to the stairs. Stability criteria is developed for any vehicle dimensions and orientation, on any staircase. All possible yaw and pitch angles on various staircases are evaluated to find vehicle orientations that will allow T3 to climb with the largest margin of stability. Different controller types are investigated for controlling vertical wheel movement with the objective of keeping all wheels in contact with the stairs, providing smooth load transfer between loaded and unloaded wheels, and maintaining optimum chassis pitch and roll angles. A controller is presented that uses feedback from wheel loading, vertical wheel position, and chassis orientation sensors. The implementation of the controller is described, and T3's stair climbing performance is presented and evaluated.

Enabling All-Access Mobility for Planetary Exploration Vehicles via Transformative Reconfiguration

NASA Technical Reports Server (NTRS)

Ferguson, Scott; Mazzoleni, Andre

2016-01-01

Effective large-scale exploration of planetary surfaces requires robotic vehicles capable of mobility across chaotic terrain. Characterized by a combination of ridges, cracks and valleys, the demands of this environment can cause spacecraft to experience significant reductions in operating footprint, performance, or even result in total system loss. Significantly increasing the scientific return of an interplanetary mission is facilitated by architectures capable of real-time configuration changes that go beyond that of active suspensions while concurrently meeting system, mass, power, and cost constraints. This Phase 1 report systematically explores how in-service architecture changes can expand system capabilities and mission opportunities. A foundation for concept generation is supplied by four Martian mission profiles spanning chasms, ice fields, craters and rocky terrain. A fifth mission profile centered on Near Earth Object exploration is also introduced. Concept generation is directed using four transformation principles - a taxonomy developed by the engineering design community to explain the cause of an architecture change and existing brainstorming techniques. This allowed early conceptual sketches of architecture changes to be organized by the principle driving the greatest increase in mission performance capability.

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

NASA Astrophysics Data System (ADS)

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.

In Vitro Evaluation of Eslicarbazepine Delivery via Enteral Feeding Tubes.

PubMed

Reindel, Kristin; Zhao, Fang; Hughes, Susan; Dave, Vivek S

2017-12-01

Purpose: The feasibility of preparing an eslicarbazepine acetate suspension using Aptiom tablets for administration via enteral feeding tubes was evaluated. Methods: Eslicarbazepine acetate suspension (40 mg/mL) was prepared using Aptiom tablets after optimizing the tablet crushing methods and the vehicle composition. A stability-indicating high-performance liquid chromatography (HPLC) method was developed to monitor the eslicarbazepine stability in the prepared suspension. Three enteric feeding tubes of various composition and dimensions were evaluated for the delivery of the suspensions. The suspension was evaluated for the physical and chemical stability for 48 hours. Results: The reproducibility and consistency of particle size reduction was found to be best with standard mortar/pestle. The viscosity analysis and physical stability studies showed that ORA-Plus:water (50:50 v/v) was optimal for suspending ability and flowability of suspension through the tubes. The developed HPLC method was found to be stability indicating and suitable for the assay of eslicarbazepine acetate in the prepared suspension. The eslicarbazepine concentrations in separately prepared suspensions were within acceptable range (±3%), indicating accuracy and reproducibility of the procedure. The eslicarbazepine concentrations in suspensions before and after delivery through the enteric feeding tubes were within acceptable range (±4%), indicating absence of any physical/chemical interactions of eslicarbazepine with the tubes and a successful delivery of eslicarbazepine dosage via enteric feeding tubes. The stability study results showed that eslicarbazepine concentration in the suspension remained unchanged when stored at room temperature for 48 hours. Conclusion: The study presents a convenient procedure for the preparation of a stable suspension of eslicarbazepine acetate (40 mg/mL) using Aptiom tablets, for administration via enteral feeding tubes.

Characterization of an extemporaneous liquid formulation of lisinopril.

PubMed

Thompson, Karen C; Zhao, Zhongxi; Mazakas, Jessica M; Beasley, Christopher A; Reed, Robert A; Moser, Cheryl L

2003-01-01

The stability of lisinopril in an extemporaneously prepared suspension stored at or below 25 degrees C for 28 days under ambient light exposure was studied. A formulation of 1-mg/mL oral suspension was prepared from commercially available 20-mg lisinopril tablets, using Bicitra and Ora-Sweet SF as the compounding vehicles to make a final volume of 200 mL. Individual samples, stored in 8-oz amber polyethylene terephthalate bottles, were used for each test performed. All samples were stored at 25 degrees C. Appropriateness of the extemporaneous preparation method was performed by shaking three lots of each suspension for 30, 60, and 90 seconds. To test the robustness and reproducibility of the method, two chemists prepared the suspensions from the same three lots of lisinopril tablets. Chemical and physical stability were established by analyzing duplicate samples at time zero and after one, two, four, and six weeks. The solubility of lisinopril was tested from suspensions stored for four weeks. In-use stability was also examined over four weeks. Photochemical stability was examined by exposing three batches of the suspension to maximum light stress in accordance with the International Conference on Harmonization. Antimicrobial-effectiveness testing was also conducted with freshly prepared suspensions and suspensions stored for six weeks. The preparation method used was appropriate and effective. Lisinopril is fully dissolved in the suspension matrix. Satisfactory chemical, physical, and microbiological results were obtained after the suspensions were stored for six weeks at 25 degrees C and 35% relative humidity. Lisinopril suspensions extemporaneously prepared from tablets are stable for at least four weeks when stored at or below 25 degrees C under ambient light exposure.

Stability of Metronidazole Suspensions.

PubMed

Donnelly, Ronald F; Ying, James

2015-01-01

Metronidazole is an antiprotozoal agent used in the treatment of bacterial and protozoal anaerobic infections. The objectives of this study were to develop concentrated metronidazole suspensions that are inexpensive and easy to prepare and determine the stability of these suspensions after storage in amber polyvinyl chloride bottles at room temperature (23°C) and under refrigeration (5°C). Metronidazole suspensions (50 mg/mL) were prepared from powder using Ora-Blend or simple syrup as the vehicles. Samples were collected in triplicate from each container on days 0, 7, 14, 28, 56, and 93. Samples were assayed using a high-performance liquid chromatography method that had been validated as stability indicating. Color, change in physical appearance, and pH were also monitored at each time interval. There was no apparent change in color or physical appearance. The pH values changed by less than 0.20 units over the 93 days. The stability of metronidazole suspensions compounded from United States Pharmacopeia powder using Ora-Blend or simple syrup and packaged in amber polyvinyl chloride bottles was determined to be 93 days when stored at either room temperature or under refrigeration.

Jim Powell: Maglev Pioneer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Powell, Jim

2016 marks the 50th anniversary of the first published paper on Maglev by retired Brookhaven Lab scientists Gordon Danby and James Powell. The two researchers invented and patented maglev technology — the suspension, guidance, and propulsion of vehicles by magnetic forces.

Suspension Bridge Structural Systems: Cable Suspension & Anchorage; Warren Stiffening ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Suspension Bridge Structural Systems: Cable Suspension & Anchorage; Warren Stiffening Truss; Upper & Lower Decks; Assembled System - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

An overview of integrated flywheel technology for aerospace application

NASA Technical Reports Server (NTRS)

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

1985-01-01

Space missions ranging from small scientific satellites to large manned spacecraft have, for many years, utilized systems of spinning flywheels to maintain vehicle attitude. These systems have included momentum and reaction wheels as well as control moment gyros. Extension of that technology to satisfy the additional tasks associated with energy storage has also been pursued. The combining of control and energy storage features into one system has been examined by NASA for space applications and demonstrated in the laboratory. The impact of technology advances in such areas as composite material rotors, magnetic suspensions, motor/generators, and electronics have prompted a re-evaluation of the viability of the flywheel storage system concept for aerospace applications. This paper summarizes the results of this re-examination and identifies shortfalls in the various technology areas.

Parachute-deployment-parameter identification based on an analytical simulation of Viking BLDT AV-4

NASA Technical Reports Server (NTRS)

Talay, T. A.

1974-01-01

A six-degree-of-freedom analytical simulation of parachute deployment dynamics developed at the Langley Research Center is presented. A comparison study was made using flight results from the Viking Balloon Launched Decelerator Test (BLDT) AV-4. Since there are significant voids in the knowledge of vehicle and decelerator aerodynamics and suspension system physical properties, a set of deployment-parameter input has been defined which may be used as a basis for future studies of parachute deployment dynamics. The study indicates the analytical model is sufficiently sophisticated to investigate parachute deployment dynamics with reasonable accuracy.

Optimisation of active suspension control inputs for improved vehicle ride performance

NASA Astrophysics Data System (ADS)

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

2016-07-01

A collocation-type control variable optimisation method is used in the paper to analyse to which extent the fully active suspension (FAS) can improve the vehicle ride comfort while preserving the wheel holding ability. The method is first applied for a cosine-shaped bump road disturbance of different heights, and for both quarter-car and full 10 degree-of-freedom vehicle models. A nonlinear anti-wheel hop constraint is considered, and the influence of bump preview time period is analysed. The analysis is then extended to the case of square- or cosine-shaped pothole with different lengths, and the quarter-car model. In this case, the cost function is extended with FAS energy consumption and wheel damage resilience costs. The FAS action is found to be such to provide a wheel hop over the pothole, in order to avoid or minimise the damage at the pothole trailing edge. In the case of long pothole, when the FAS cannot provide the wheel hop, the wheel is travelling over the pothole bottom and then hops over the pothole trailing edge. The numerical optimisation results are accompanied by a simplified algebraic analysis.

Development of a frontal small overlap crashworthiness evaluation test.

PubMed

Sherwood, Christopher P; Mueller, Becky C; Nolan, Joseph M; Zuby, David S; Lund, Adrian K

2013-01-01

Small overlap frontal crashes are those in which crash forces are applied outboard of the vehicle's longitudinal frame rails. In-depth analyses of crashes indicate that such crashes account for a significant proportion of frontal crashes with seriously injured occupants. The objective of this research was to evaluate possible barrier crash tests that could be used to evaluate the crashworthiness of vehicles across a spectrum of small overlap crash types. Sixteen full-scale vehicle tests were conducted using 3 midsize passenger vehicles in up to 6 different test configurations, including vehicle-to-vehicle and barrier tests. All vehicles were tested at 64 km/h with an instrumented Hybrid III midsize male driver dummy. All test configurations resulted in primary loading of the wheel, suspension system, and hinge pillar. Vehicles underwent substantial lateral movement during the crash, which varied by crash configuration. The occupant compartments had significant intrusion, particularly to the most outboard structures. Inboard movement of the steering wheel in combination with outboard movement of the dummies (due to the lateral vehicle motion) caused limited interaction with the frontal air bag in most cases. When assessing overall crashworthiness (based on injury measures, structural deformation, and occupant kinematics), one vehicle had superior performance in each crash configuration. This was confirmation that the countermeasures benefiting performance in a single small overlap test also will provide a benefit in other crash configurations. Based on these test results, the Insurance Institute for Highway Safety has developed a small overlap crashworthiness evaluation with the following characteristics: a rigid flat barrier with a 150-mm corner radius, 25 percent overlap, 64 km/h test speed, and a Hybrid III midsize male driver dummy.

Integrated control of lateral and vertical vehicle dynamics based on multi-agent system

NASA Astrophysics Data System (ADS)

Huang, Chen; Chen, Long; Yun, Chaochun; Jiang, Haobin; Chen, Yuexia

2014-03-01

The existing research of the integrated chassis control mainly focuses on the different evaluation indexes and control strategy. Among the different evaluation indexes, the comprehensive properties are usually not considered based on the non-linear superposition principle. But, the control strategy has some shortages on tyre model with side-slip angle, road adhesion coefficient, vertical load and velocity. In this paper, based on belief, desire and intention(BDI)-agent model framework, the TYRE agent, electric power steering(EPS) agent and active suspension system(ASS) agent are proposed. In the system(SYS) agent, the coordination mechanism is employed to manage interdependences and conflicts among other agents, so as to improve the flexibility, adaptability, and robustness of the global control system. Due to the existence of the simulation demand of dynamic performance, the vehicle multi-body dynamics model is established by SIMPACK. And then the co-simulation analysis is conducted to evaluate the proposed multi-agent system(MAS) controller. The simulation results demonstrate that the MAS has good effect on the performance of EPS and ASS. Meantime, the better road feeling for the driver is provided considering the multiple and complex driving traffic. Finally, the MAS rapid control prototyping is built to conduct the real vehicle test. The test results are consistent to the simulation results, which verifies the correctness of simulation. The proposed research ensures the driving safety, enhances the handling stability, and improves the ride comfort.

The effects of particle properties on nanoparticle drug retention and release in dynamic minoxidil foams.

PubMed

Zhao, Yanjun; Brown, Marc B; Jones, Stuart A

2010-01-04

Nanocarriers may act as useful tools to deliver therapeutic agents to the skin. However, balancing the drug-particle interactions; to ensure adequate drug loading, with the drug-vehicle interactions; to allow efficient drug release, presents a significant challenge using traditional semi-solid vehicles. The aim of this study was to determine how the physicochemical properties of nanoparticles influenced minoxidil release pre and post dose application when formulated as a simple aqueous suspension compared to dynamic hydrofluoroalkane (HFA) foams. Minoxidil loaded lipid nanoparticles (LN, 1.4 mg/ml, 50 nm) and polymeric nanoparticles with a lipid core (PN, 0.6 mg/ml, 260 nm) were produced and suspended in water to produce the aqueous suspensions. These aqueous suspensions were emulsified with HFA using pluronic surfactant to generate the foams. Approximately 60% of the minoxidil loaded into the PN and 80% of the minoxidil loaded into the LN was released into the external aqueous phase 24h after production. Drug permeation was superior from the PN, i.e. it was the particle that retained the most drugs, irrespective of the formulation method. Premature drug release, i.e. during storage, resulted in the performance of the topical formulation being dictated by the thermodynamic activity of the solubilised drug not the particle properties.

32 CFR 634.47 - Disposition of driving records.

Code of Federal Regulations, 2010 CFR

2010-07-01

... ENFORCEMENT AND CRIMINAL INVESTIGATIONS MOTOR VEHICLE TRAFFIC SUPERVISION Driving Records and the Traffic... accumulation of traffic points. Traffic points for persons being transferred will continue to accumulate as... on the driver record regarding suspensions, revocations, moving violations, or chargeable accidents...

40 CFR 86.614-84 - Hearings on suspension, revocation, and voiding of certificates of conformity.

Code of Federal Regulations, 2011 CFR

2011-07-01

... there exists a basis for distinguishing vehicles produced at plants other than the one from which... any such action shall have an adequate opportunity, once he learns the name of a witness and obtains...

Jim Powell: Maglev Pioneer

ScienceCinema

Powell, Jim

2018-06-12

2016 marks the 50th anniversary of the first published paper on Maglev by retired Brookhaven Lab scientists Gordon Danby and James Powell. The two researchers invented and patented maglev technology — the suspension, guidance, and propulsion of vehicles by magnetic forces.

Stability of gabapentin in extemporaneously compounded oral suspensions

PubMed Central

Friciu, Mihaela; Roullin, V. Gaëlle

2017-01-01

This study reports the stability of extemporaneously prepared gabapentin oral suspensions prepared at 100 mg/mL from bulk drug and capsules in either Oral Mix or Oral Mix SF suspending vehicles. Suspensions were packaged in amber plastic bottles and amber plastic syringes at 25°C / 60%RH for up to 90 days. Throughout the study period, the following tests were performed to evaluate the stability of the preparations: organoleptic inspection to detect homogeneity, color or odor changes; pH measurements; and gabapentin assay using a stability-indicating HPLC-UV method. As crystallization was observed at 5°C, storage at this temperature condition is not recommended. All preparations stored at 25°C / 60%RH remained stable for the whole study duration of 90 days. PMID:28414771

Multi-functional Electric Module for a Vehicle

NASA Technical Reports Server (NTRS)

Waligora, Thomas M. (Inventor); Fraser-Chanpong, Nathan (Inventor); Figuered, Joshua M. (Inventor); Reed, Ryan (Inventor); Akinyode, Akinjide Akinniyi (Inventor); Spain, Ivan (Inventor); Dawson, Andrew D. (Inventor); Herrera, Eduardo (Inventor); Markee, Mason M. (Inventor); Bluethmann, William J. (Inventor)

2015-01-01

A multi-functional electric module (eModule) is provided for a vehicle having a chassis, a master controller, and a drive wheel having a propulsion-braking module. The eModule includes a steering control assembly, mounting bracket, propulsion control assembly, brake controller, housing, and control arm. The steering control assembly includes a steering motor controlled by steering controllers in response to control signals from the master controller. A mounting feature of the bracket connects to the chassis. The propulsion control assembly and brake controller are in communication with the propulsion-braking module. The control arm connects to the lower portion and contains elements of a suspension system, with the control arm being connectable to the drive wheel via a wheel input/output block. The controllers are responsive to the master controller to control a respective steering, propulsion, and braking function. The steering motor may have a dual-wound stator with windings controlled via the respective steering controllers.

Dynamic modelling and experimental validation of three wheeled tilting vehicles

NASA Astrophysics Data System (ADS)

Amati, Nicola; Festini, Andrea; Pelizza, Luigi; Tonoli, Andrea

2011-06-01

The present paper describes the study of the stability in the straight running of a three-wheeled tilting vehicle for urban and sub-urban mobility. The analysis was carried out by developing a multibody model in the Matlab/SimulinkSimMechanics environment. An Adams-Motorcycle model and an equivalent analytical model were developed for the cross-validation and for highlighting the similarities with the lateral dynamics of motorcycles. Field tests were carried out to validate the model and identify some critical parameters, such as the damping on the steering system. The stability analysis demonstrates that the lateral dynamic motions are characterised by vibration modes that are similar to that of a motorcycle. Additionally, it shows that the wobble mode is significantly affected by the castor trail, whereas it is only slightly affected by the dynamics of the front suspension. For the present case study, the frame compliance also has no influence on the weave and wobble.

Micropellets coated with Kollicoat® Smartseal 30D for taste masking in liquid oral dosage forms.

PubMed

Dashevskiy, Andriy; Mohylyuk, Valentyn; Ahmed, Abid Riaz; Kolter, Karl; Guth, Felicitas; Bodmeier, Roland

2017-09-01

The objective of this study was to develop delivery systems for taste masking based on multiparticulates coated with Kollicoat ® Smartseal 30D formulated as liquid oral suspensions. Coating of particles containing bitter drugs with Kollicoat ® Smartseal reduced drug leaching into aqueous medium, especially when increasing pH, therefore can be used for the formulation of liquid dosage forms. Application of an intermediate layer of ion exchange resins between drug layer and coating can further decrease drug leaching into aqueous vehicle that is beneficial in terms of taste masking. Using optimized compositions of liquid vehicles such as addition of sugar alcohols and ion exchange resin, reconstitutable or ready-to-use liquid dosage forms with micropellets can be developed with bitter taste protection after redispersion lasting longer than 3 weeks, which exceeds the usual period of application.

Numerical assessment of fore-and-aft suspension performance to reduce whole-body vibration of wheel loader drivers

NASA Astrophysics Data System (ADS)

Fleury, Gérard; Mistrot, Pierre

2006-12-01

While driving off-road vehicles, operators are exposed to whole-body vibration acting in the fore-and-aft direction. Seat manufacturers supply products equipped with fore-and-aft suspension but only a few studies report on their performance. This work proposes a computational approach to design fore-and-aft suspensions for wheel loader seats. Field tests were conducted in a quarry to analyse the nature of vibration to which the driver was exposed. Typical input signals were recorded to be reproduced in the laboratory. Technical specifications are defined for the suspension. In order to evaluate the suspension vibration attenuation performance, a model of a sitting human body was developed and coupled to a seat model. The seat model combines the models of each suspension component. A linear two-degree-of-freedom model is used to describe the dynamic behaviour of the sitting driver. Model parameters are identified by fitting the computed apparent mass frequency response functions to the measured values. Model extensions are proposed to investigate postural effects involving variations in hands and feet positions and interaction of the driver's back with the backrest. Suspension design parameters are firstly optimized by computing the seat/man model response to sinusoidal acceleration. Four criteria including transmissibility, interaction force between the driver's back and the backrest and relative maximal displacement of the suspension are computed. A new suspension design with optimized features is proposed. Its performance is checked from calculations of the response of the seat/man model subjected to acceleration measured on the wheel loader during real work conditions. On the basis of the computed values of the SEAT factors, it is found possible to design a suspension that would increase the attenuation provided by the seat by a factor of two.

Technological assumptions for biogas purification.

PubMed

Makareviciene, Violeta; Sendzikiene, Egle

2015-01-01

Biogas can be used in the engines of transport vehicles and blended into natural gas networks, but it also requires the removal of carbon dioxide, hydrogen sulphide, and moisture. Biogas purification process flow diagrams have been developed for a process enabling the use of a dolomite suspension, as well as for solutions obtained by the filtration of the suspension, to obtain biogas free of hydrogen sulphide and with a carbon dioxide content that does not exceed 2%. The cost of biogas purification was evaluated on the basis of data on biogas production capacity and biogas production cost obtained from local water treatment facilities. It has been found that, with the use of dolomite suspension, the cost of biogas purification is approximately six times lower than that in the case of using a chemical sorbent such as monoethanolamine. The results showed travelling costs using biogas purified by dolomite suspension are nearly 1.5 time lower than travelling costs using gasoline and slightly lower than travelling costs using mineral diesel fuel.

Stability of extemporaneous enalapril maleate suspensions for pediatric use prepared from commercially available tablets.

PubMed

Sosnowska, Katarzyna; Winnicka, Katarzyna; Czajkowska-Kośnik, Anna

2009-01-01

In this paper, the stability of enalapril maleate in oral formulations prepared from commercially available tablets was investigated. Extemporaneously compounded, 0.1 mg/mL and 1.0 mg/mL, oral suspensions of enalapril maleate in sugar-containing and sugar-free vehicles were stored in the absence of light at 4 degrees and 25 degrees C for 30 days. Enalapril maleate stability was quantified after 7, 14, 21, and 30 days using HPLC method. Viscosities and pH of prepared suspensions were measured on each study day and no appreciable changes from the initial pH and initial viscosities occurred in any of the samples both at 25 degrees and 4 degrees C. It was shown that all the formulations retain minimum 98% of the initial enalapril maleate concentration after 30 days of storage at 25 degrees and 4 degrees C and they may provide an option in situations where the marketed suspension is unavailable.

An observational study of the effect of vibration on the caking of suspensions in oily vehicles.

PubMed

Jain, Rohit; Bork, Olaf; Alawi, Fadil; Nanjan, Karthigeyan; Tucker, Ian G

2016-11-30

An oily suspension of penethamate (PNT) that was physically stable on storage, caked solidly during road/air transport. This paper reports on the caking behaviour of PNT oily suspension formulations exposed to vibrations in a lab-based test designed to simulate road/air transport. The lab-test was used to study the effects of container type (glass v PET) and formulation (oil, surfactant type and concentration) on the physical stability of suspension under vibration. Redispersibility of the sediment was lower at longer vibrations times and at higher intensity of vibration. Caking on vibration was strongly influenced by the type of container (caking in glass but not in PET) possibly due to tribo-charging of particles. Caking on vibration was dependent on the formulation: type and concentration of surfactant; type of oil. The physical stability of oily suspensions, and the effect of vibration are two areas which have been largely neglected in the pharmaceutical literature. This paper discusses some potential mechanisms for the observations but studies using fully characterised materials are required. Finally we conclude that static testing of physical stability of oily suspensions is not sufficient and that a vibrational stress test is required. Copyright © 2016 Elsevier B.V. All rights reserved.

Changes in alcohol-involved fatal crashes associated with tougher state alcohol legislation

DOT National Transportation Integrated Search

1989-07-01

From 1982 to 1988, many states implemented statutes, such as administrative suspension of driver licenses and mandatory jail terms and/or fines for persons convicted of drunk driving, intended to reduce the incidence of alcohol-related motor vehicle ...

32 CFR 634.17 - Extensions of suspensions and revocations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) LAW ENFORCEMENT AND CRIMINAL INVESTIGATIONS MOTOR VEHICLE TRAFFIC SUPERVISION Driving Privileges... traffic, criminal, or military offenses, for example, active duty military personnel driving on the... or alcohol or drug counseling programs after proof is provided. (d) Commanders may extend a...

A comparative work on vibration control of a quarter car suspension system with two different magneto-rheological dampers

NASA Astrophysics Data System (ADS)

Park, Jhin Ha; Kim, Wan Ho; Shin, Cheol Soo; Choi, Seung-Bok

2017-01-01

This work compares the ride comfort of a passenger vehicle whose suspension system is equipped with two different magneto-rheological (MR) dampers: with and without bypass holes in the piston. In order to achieve this goal, two cylindrical type MR dampers, which otherwise have the same such geometrical dimensions as radius of piston, length of pole and distance between two poles, are designed based on a mathematical model and subsequently manufactured. One of MR dampers is then modified by making bypass holes in the piston bobbin structure to obtain a relatively low slope of damping force in the pre-yield region. The field-dependent damping force characteristics are investigated through both simulation and experiment. After characterizing the field-dependent damping force of the two MR dampers, a quarter car model is established to evaluate the ride comfort. In this work, a simple but very effective sky-hook controller is adopted, and vibration control performance is evaluated under two road profiles: bump and random road excitations. It is demonstrated through simulation and experiment that the MR damper with bypass holes provides better ride comfort to the car so equipped than that without.

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

PubMed

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.

Aerospace Applications of Magnetic Suspension Technology, part 1

NASA Technical Reports Server (NTRS)

Groom, Nelson J. (Editor); Britcher, Colin P. (Editor)

1991-01-01

Papers presented at the conference on aerospace applications of magnetic suspension technology are compiled. The following subject areas are covered: pointing and isolation systems; microgravity and vibration isolation; bearing applications; wind tunnel model suspension systems; large gap magnetic suspension systems; control systems; rotating machinery; science and application of superconductivity; and sensors.

A new composite adaptive controller featuring the neural network and prescribed sliding surface with application to vibration control

NASA Astrophysics Data System (ADS)

Phu, Do Xuan; Huy, Ta Duc; Mien, Van; Choi, Seung-Bok

2018-07-01

This work proposes a novel composite adaptive controller based on the prescribed performance of the sliding surface and applies it to vibration control of a semi-active vehicle seat suspension system subjected to severe external disturbances. As a first step, the online fast interval type 2 fuzzy neural network system is adopted to establish a model and two sliding surfaces are used; conventional surface and prescribed surface. Then, an equivalent control is determined by assuming the derivative of the prescribed surface is zero, followed by the design of a controller which can guarantee both stability and robustness. Then, two controllers are combined and integrated with adaptation laws using the projection algorithm. The effectiveness of the proposed composite controller is validated through both simulation and experiment by undertaking vibration control of a semi-active seat suspension system equipped with a magneto-rheological (MR) damper. It is shown from both simulation and experimental realization that excellent vibration control performances are achieved with a small tracking error between the proposed and prescribed objectives. In addition, the control superiority of the proposed controller to conventional sliding mode controller featuring one sliding surface and proportional-integral-derivative (PID) controllers are demonstrated through a comparative work.

Preparation and evaluation of a self-emulsifying drug delivery system of etoposide-phospholipid complex.

PubMed

Wu, Zhongbin; Guo, Dan; Deng, Li; Zhang, Yue; Yang, Qiuxia; Chen, Jianming

2011-01-01

The aim of this study was to develop a new phospholipid complex self-emulsifying drug delivery system (PC-SEDDS) to enhance bioavailability of oral etoposide, a drug with poor water solubility. Etoposide-phospholipid complex (EPC) was prepared by reacting etoposide and phospholipid in tetrahydrofuran and confirmed as a phospholipid compound by differential scanning calorimetry (DSC). Solubility of EPC and etoposide was determined in various vehicles. Pseudoternary phase diagrams were constructed to identify the efficient self-emulsification region of EPC-SEDDS, and the effects of oil concentration, drug loading, and aqueous media on droplet size were investigated. The optimal formulation of EPC-SEDDS was EPC:octyl and decyl monoglyceride (ODO):Cremopher EL:PEG-400 (1:20:48:32) (w/w/w/w). Compared with etoposide-phospholipid complex suspension (EPCS) and etoposide suspension (ES), cumulative release of etoposide from EPC-SEDDS increased by 1.31 and 2.65 fold at 24 hours, respectively. Compared with ES, relative bioavailability of EPC-SEDDS, E-SEDDS, and EPCS after oral administration in rats was enhanced by 60.21-, 44.9-, and 8.44- fold, respectively. The synergistic effect between PC and SEDDS contributed to the enhanced bioavailability of etoposide. It was concluded that PC-SEDDS proved to be a potential system for delivering orally administered hydrophobic compounds including etoposide.

In vitro cellular uptake of evodiamine and rutaecarpine using a microemulsion

PubMed Central

Zhang, Yong-Tai; Huang, Zhe-Bin; Zhang, Su-Juan; Zhao, Ji-Hui; Wang, Zhi; Liu, Ying; Feng, Nian-Ping

2012-01-01

Objective To investigate the cellular uptake of evodiamine and rutaecarpine in a microemulsion in comparison with aqueous suspensions and tinctures. Materials and methods A microemulsion was prepared using the dropwise addition method. Mouse skin fibroblasts were cultured in vitro to investigate the optimal conditions for evodiamine and rutaecarpine uptake with different drug concentrations and administration times. Under optimal conditions, the cellular uptake of microemulsified drugs was assayed and compared to tinctures and aqueous suspensions. Rhodamine B labeling and laser scanning confocal microscopy (LSCM) were used to explore the distribution of fluorochrome transferred with the microemulsion in fibroblasts. Cellular morphology was also investigated, using optical microscopy to evaluate microemulsion-induced cellular toxicity. Results The maximum cellular drug uptake amounts were obtained with a 20% concentration (v/v) of microemulsion and an 8 hour administration time. Drug uptake by mouse skin fibroblasts was lowest when the drugs were loaded in microemulsion. After incubation with rhodamine B-labeled microemulsion for 8 hours, the highest fluorescence intensity was achieved, and the fluorochrome was primarily distributed in the cytochylema. No obvious cellular morphologic changes were observed with the administration of either the microemulsion or the aqueous suspension; for the tincture group, however, massive cellular necrocytosis was observed. Conclusion The lower cellular uptake with microemulsion may be due to the fact that most of the drug loaded in the microemulsion vehicle was transported via the intercellular space, while a small quantity of free drug (released from the vehicle) was ingested through transmembrane transport. Mouse skin fibroblasts rarely endocytosed evodiamine and rutaecarpine with a microemulsion as the vehicle. The microemulsion had no obvious effect on cellular morphology, suggesting there is little or no cellular toxicity associated with the administration of microemulsion on mouse skin fibroblasts. PMID:22679361

In vitro cellular uptake of evodiamine and rutaecarpine using a microemulsion.

PubMed

Zhang, Yong-Tai; Huang, Zhe-Bin; Zhang, Su-Juan; Zhao, Ji-Hui; Wang, Zhi; Liu, Ying; Feng, Nian-Ping

2012-01-01

To investigate the cellular uptake of evodiamine and rutaecarpine in a microemulsion in comparison with aqueous suspensions and tinctures. A microemulsion was prepared using the dropwise addition method. Mouse skin fibroblasts were cultured in vitro to investigate the optimal conditions for evodiamine and rutaecarpine uptake with different drug concentrations and administration times. Under optimal conditions, the cellular uptake of microemulsified drugs was assayed and compared to tinctures and aqueous suspensions. Rhodamine B labeling and laser scanning confocal microscopy (LSCM) were used to explore the distribution of fluorochrome transferred with the microemulsion in fibroblasts. Cellular morphology was also investigated, using optical microscopy to evaluate microemulsion-induced cellular toxicity. The maximum cellular drug uptake amounts were obtained with a 20% concentration (v/v) of microemulsion and an 8 hour administration time. Drug uptake by mouse skin fibroblasts was lowest when the drugs were loaded in microemulsion. After incubation with rhodamine B-labeled microemulsion for 8 hours, the highest fluorescence intensity was achieved, and the fluorochrome was primarily distributed in the cytochylema. No obvious cellular morphologic changes were observed with the administration of either the microemulsion or the aqueous suspension; for the tincture group, however, massive cellular necrocytosis was observed. The lower cellular uptake with microemulsion may be due to the fact that most of the drug loaded in the microemulsion vehicle was transported via the intercellular space, while a small quantity of free drug (released from the vehicle) was ingested through transmembrane transport. Mouse skin fibroblasts rarely endocytosed evodiamine and rutaecarpine with a microemulsion as the vehicle. The microemulsion had no obvious effect on cellular morphology, suggesting there is little or no cellular toxicity associated with the administration of microemulsion on mouse skin fibroblasts.

A NARX damper model for virtual tuning of automotive suspension systems with high-frequency loading

NASA Astrophysics Data System (ADS)

Alghafir, M. N.; Dunne, J. F.

2012-02-01

A computationally efficient NARX-type neural network model is developed to characterise highly nonlinear frequency-dependent thermally sensitive hydraulic dampers for use in the virtual tuning of passive suspension systems with high-frequency loading. Three input variables are chosen to account for high-frequency kinematics and temperature variations arising from continuous vehicle operation over non-smooth surfaces such as stone-covered streets, rough or off-road conditions. Two additional input variables are chosen to represent tuneable valve parameters. To assist in the development of the NARX model, a highly accurate but computationally excessive physical damper model [originally proposed by S. Duym and K. Reybrouck, Physical characterization of non-linear shock absorber dynamics, Eur. J. Mech. Eng. M 43(4) (1998), pp. 181-188] is extended to allow for high-frequency input kinematics. Experimental verification of this extended version uses measured damper data obtained from an industrial damper test machine under near-isothermal conditions for fixed valve settings, with input kinematics corresponding to harmonic and random road profiles. The extended model is then used only for simulating data for training and testing the NARX model with specified temperature profiles and different valve parameters, both in isolation and within quarter-car vehicle simulations. A heat generation and dissipation model is also developed and experimentally verified for use within the simulations. Virtual tuning using the quarter-car simulation model then exploits the NARX damper to achieve a compromise between ride and handling under transient thermal conditions with harmonic and random road profiles. For quarter-car simulations, the paper shows that a single tuneable NARX damper makes virtual tuning computationally very attractive.

A semi-active damper in vertical secondary suspension for the comfort increase in passenger trains

NASA Astrophysics Data System (ADS)

Ripamonti, Francesco; Chiarabaglio, Andrea; Resta, Ferruccio

2017-04-01

Passive oil dampers for railway vehicles present a damping and stiffness characteristics, which depend from excitation history. This behaviour is not acceptable for many high-performance applications. A mechatronic approach, able to continuously adjust the damping coefficient according to the operation requirements, represents a very attractive and smart solution. In this paper, a control strategy for semi-active dampers of train vertical secondary suspensions is presented. The controller aims at assuring the maximum available damping at low frequencies, while at high frequencies minimizes the force transmitted to the carbody that excites the bending modes.

High-fidelity simulation capability for virtual testing of seismic and acoustic sensors

NASA Astrophysics Data System (ADS)

Wilson, D. Keith; Moran, Mark L.; Ketcham, Stephen A.; Lacombe, James; Anderson, Thomas S.; Symons, Neill P.; Aldridge, David F.; Marlin, David H.; Collier, Sandra L.; Ostashev, Vladimir E.

2005-05-01

This paper describes development and application of a high-fidelity, seismic/acoustic simulation capability for battlefield sensors. The purpose is to provide simulated sensor data so realistic that they cannot be distinguished by experts from actual field data. This emerging capability provides rapid, low-cost trade studies of unattended ground sensor network configurations, data processing and fusion strategies, and signatures emitted by prototype vehicles. There are three essential components to the modeling: (1) detailed mechanical signature models for vehicles and walkers, (2) high-resolution characterization of the subsurface and atmospheric environments, and (3) state-of-the-art seismic/acoustic models for propagating moving-vehicle signatures through realistic, complex environments. With regard to the first of these components, dynamic models of wheeled and tracked vehicles have been developed to generate ground force inputs to seismic propagation models. Vehicle models range from simple, 2D representations to highly detailed, 3D representations of entire linked-track suspension systems. Similarly detailed models of acoustic emissions from vehicle engines are under development. The propagation calculations for both the seismics and acoustics are based on finite-difference, time-domain (FDTD) methodologies capable of handling complex environmental features such as heterogeneous geologies, urban structures, surface vegetation, and dynamic atmospheric turbulence. Any number of dynamic sources and virtual sensors may be incorporated into the FDTD model. The computational demands of 3D FDTD simulation over tactical distances require massively parallel computers. Several example calculations of seismic/acoustic wave propagation through complex atmospheric and terrain environments are shown.

Development and validation of a discriminative dissolution test for nimesulide suspensions.

PubMed

da Fonseca, Laís Bastos; Labastie, Márcio; de Sousa, Valéria Pereira; Volpato, Nadia Maria

2009-01-01

The dissolution test for oral dosage forms has recently widened to a variety of special dosage forms such as suspensions. For class II drugs, such as nimesulide (NMS), this study is very important because formulation problems may compromise drug bioavailability. In the present work, tests with four brands of commercially available NMS (RA, TS, TB, and TC) have been performed in order to study their dissolution at different conditions. The suspensions have been characterized relatively to particle size, pH, and density besides NMS assay and the amount of drug in solution in the suspension vehicles. The dissolution study was conducted using the following media: simulated intestinal fluid, pH 6.8, containing polysorbate 80 (P80) or sodium lauryl sulfate (SLS); phosphate buffer, pH 7.4, with P80 and aqueous solution of SLS. Concerning the quantitative analysis, the UV-VIS spectrophotometry could have been used in substitution to high-performance liquid chromatography since the methodology had been adequately validated. The influence of the drug particle size distribution was significant on the dissolution profiles of NMS formulations, confirming to be a factor that should be strictly controlled in the development of oral suspensions.

Stowable Energy-Absorbing Rocker-Bogie Suspensions

NASA Technical Reports Server (NTRS)

Harrington, Brian; Voorhees, Christopher

2007-01-01

A report discusses the design of the rocker-bogie suspensions of the Mars Exploration Rover vehicles, which were landed on Mars in January 2004. Going beyond the basic requirements regarding mobility on uneven terrain, the design had to satisfy requirements (1) to enable each suspension to contort so that the rover could be stowed within limited space in a tetrahedral lander prior to deployment and (2) that the suspension be able to absorb appreciable impact loads, with limited deflection, during egress from the lander and traversal of terrain. For stowability, six joints (three on the right, three on the left) were added to the basic rocker-bogie mechanism. One of the joints on each side was a yoke-and-clevis joint at the suspension/differential interface, one was a motorized twist joint in the forward portion of the rocker, and one was a linear joint created by modifying a fixed-length bogie member into a telescoping member. For absorption of impact, the structural members were in the form of box beams made by electron-beam welding of machined, thin-walled, C-channel, titanium components. The box beams were very lightweight and could withstand high bending and torsional loads.

49 CFR 570.61 - Suspension system.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 6 2012-10-01 2012-10-01 false Suspension system. 570.61 Section 570.61 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY... 10,000 Pounds § 570.61 Suspension system. (a) Suspension condition. Ball joint seals shall not be cut...

49 CFR 570.61 - Suspension system.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 6 2014-10-01 2014-10-01 false Suspension system. 570.61 Section 570.61 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY... 10,000 Pounds § 570.61 Suspension system. (a) Suspension condition. Ball joint seals shall not be cut...

49 CFR 570.8 - Suspension systems.

Code of Federal Regulations, 2010 CFR

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...

Stability of Allopurinol, Amitriptyline Hydrochloride, Carbamazepine, Domperidone, Isoniazid, Ketoconazole, Lisinopril, Naproxen, Paracetamol (Acetaminophen), and Sertraline Hydrochloride in SyrSpend SF PH4 Oral Suspensions.

PubMed

Polonini, Hudson C; Loures, Sharlene; de Araujo, Edson Peter; Brandão, Marcos Antônio F; Ferreira, Anderson O

2016-01-01

Oral liquids are safe alternatives to solid dosage forms, notably for elderly and pediatric patients that present dysphagia. The use of ready-to-use suspending vehicles such as SyrSpend SF PH4 is a suitable resource for pharmacists as they constitute a safe and timesaving option that has been studied often. The objective of this study was to evaluate the stability of 10 commonly used active pharmaceutical ingredients (allopurinol 20 mg/mL; amitriptyline hydrochloride 10 mg/mL; carbamazepine 25 mg/mL; domperidone 5 mg/mL; isoniazid 10 mg/mL; ketoconazole 20 mg/mL; lisinopril 1 mg/mL; naproxen 25 mg/mL; paracetamol [acetaminophen] 50 mg/mL; and sertraline hydrochloride 10 mg/mL) compounded in oral suspensions using SyrSpend SF PH4 as the vehicle throughout the study period and stored both at controlled refrigerated (2°C to 8°C) and room temperature (20°C to 25°C). Stability was assessed by means of measuring the percent recovery at varying time points throughout a 90-day period. The quantification of the active pharmaceutical ingredients was performed by high-performance liquid chromatography through a stability-indicating method. Methods were adequately validated. Forced-degradation studies showed that at least one parameter influenced the stability of the active pharmaceutical ingredients. All suspensions were assayed and showed active pharmaceutical ingredient contents between 90% and 110% during the 90-day study period. Although the forced-degradation experiments led to visible fluctuations in the chromatographic responses, the final preparations were stable in the storage conditions. The beyond-use dates of the preparations were found to be at least 90 days for all suspensions, both for controlled refrigerated temperature and room temperature. This confirms that SyrSpend SF PH4 is a stable suspending vehicle for compounding with a broad range of different active pharmaceutical ingredients for different medical usages. Copyright© by International Journal of Pharmaceutical Compounding, Inc.

Structural evaluation of the John A. Roebling Suspension Bridge : element level analysis.

DOT National Transportation Integrated Search

2008-07-01

The primary objective of the structural evaluation of the John A. Roebling Bridge is to determine the maximum allowable gross vehicle weight (GVW) that can be carried by the bridge deck structural elements such as the open steel grid deck, channels, ...

32 CFR 634.17 - Extensions of suspensions and revocations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... ENFORCEMENT AND CRIMINAL INVESTIGATIONS MOTOR VEHICLE TRAFFIC SUPERVISION Driving Privileges § 634.17... years. In addition, administrative action may be initiated based on the commission of any traffic... or alcohol or drug counseling programs after proof is provided. (d) Commanders may extend a...

Nonlinear finite element analysis of liquid sloshing in complex vehicle motion scenarios

NASA Astrophysics Data System (ADS)

Nicolsen, Brynne; Wang, Liang; Shabana, Ahmed

2017-09-01

The objective of this investigation is to develop a new total Lagrangian continuum-based liquid sloshing model that can be systematically integrated with multibody system (MBS) algorithms in order to allow for studying complex motion scenarios. The new approach allows for accurately capturing the effect of the sloshing forces during curve negotiation, rapid lane change, and accelerating and braking scenarios. In these motion scenarios, the liquid experiences large displacements and significant changes in shape that can be captured effectively using the finite element (FE) absolute nodal coordinate formulation (ANCF). ANCF elements are used in this investigation to describe complex mesh geometries, to capture the change in inertia due to the change in the fluid shape, and to accurately calculate the centrifugal forces, which for flexible bodies do not take the simple form used in rigid body dynamics. A penalty formulation is used to define the contact between the rigid tank walls and the fluid. A fully nonlinear MBS truck model that includes a suspension system and Pacejka's brush tire model is developed. Specified motion trajectories are used to examine the vehicle dynamics in three different scenarios - deceleration during straight-line motion, rapid lane change, and curve negotiation. It is demonstrated that the liquid sloshing changes the contact forces between the tires and the ground - increasing the forces on certain wheels and decreasing the forces on other wheels. In cases of extreme sloshing, this dynamic behavior can negatively impact the vehicle stability by increasing the possibility of wheel lift and vehicle rollover.

A Study on Design and Analysis of Hybrid Vibration Damper with Energy Harvesting and Optimal Damping Effect

NASA Astrophysics Data System (ADS)

Hanumantha Rao, T. V.; Srinivasa Rao, M. S. S.; Apparao, B. V.; Satyanarayana, K.

2014-04-01

The basic purpose of a damper is to reduce the vibration and to have a better ride comfort, road handling and safety to the rider. Recent developments show that an active vibration damper can effectively work much better than a passive damper. The effectiveness and reliability can be further enhanced by using hybrid dampers, which is a combination of active and passive dampers. But the need to have energy optimization in any field need not be stressed. Consequently, novel suspension concepts are required, not only to improve the vehicle's dynamic performance, but also to see that the energy generated during vibration can be harvested by utilizing regeneration functions. Hence if a hybrid damper with energy harvesting capability be designed, it would serve both purposes. In the hybrid damper a combination of hydraulic damper to act as a passive damper and an electromagnetic (EM) damper to act as an active damper is considered. The hydraulic system has more reliability and is time tested and the EM system acts as a dynamic vibration system as well as energy harvester. In this study a hybrid EM damper is modeled, analyzed and validity is shown for frequency response functions and energy balance for its active use. It is also shown how the effectiveness of the suspension system can be enhanced by using a hybrid damper.

A comparison of dispersing media for various engineered carbon nanoparticles.

PubMed

Buford, Mary C; Hamilton, Raymond F; Holian, Andrij

2007-07-27

With the increased manufacture and use of carbon nanoparticles (CNP) there has been increasing concern about the potential toxicity of fugitive CNP in the workplace and ambient environment. To address this matter a number of investigators have conducted in vitro and in vivo toxicity assessments. However, a variety of different approaches for suspension of these particles (culture media, Tween 80, dimethyl sulfoxide, phosphate-buffered saline, fetal calf serum, and others), and different sources of materials have generated potentially conflicting outcomes. The quality of the dispersion of nanoparticles is very dependent on the medium used to suspend them, and this then will most likely affect the biological outcomes. In this work, the distributions of different CNP (sources and types) have been characterized in various media. Furthermore, the outcome of instilling the different agglomerates, or size distributions, was examined in mouse lungs after one and seven days. Our results demonstrated that CNP suspended in serum produced particle suspensions with the fewest large agglomerates, and the most uniform distribution in mouse lungs. In addition, no apparent clearance of instilled CNP took place from lungs even after seven days. This work demonstrates that CNP agglomerates are present in all dispersing vehicles to some degree. The vehicle that contains some protein, lipid or protein/lipid component disperses the CNP best, producing fewer large CNP agglomerates. In contrast, vehicles absent of lipid and protein produce the largest CNP agglomerates. The source of the CNP is also a factor in the degree of particle agglomeration within the same vehicle.

Design, Fabrication, and Analysis of a Hybrid FIBER Composite Monoleaf Spring Using Carbon and E-Glass Fibers for Automotive Suspension Applications

NASA Astrophysics Data System (ADS)

Sureshkumar, M.; Tamilselvam, P.; Kumaravelan, R.; Dharmalingam, R.

2014-03-01

The leaf spring is an important component that provides suspension and plays a vital role in automotive applications. As a vehicle travels, a tremendous force, mostly in terms of a fatigue load, is applied to the leaf spring assembly, particularly to the eye point of the rear axle. In a vehicle with rear-wheel drive, the leaf spring is subject to twisting forces that are opposite in direction and magnitude during the acceleration of drive wheels. A multileaf spring provides an additional strength, but lacks the flexibility and increases the overall weight of the vehicle. Considering the loading conditions, the availability of space in a vehicle, and geometrical considerations, a composite monoleaf spring is designed. In due consideration of the tensile behavior, fatigue resistance, chipping resistance, and base part resistance, a hybrid laminated spring is constructed for the purpose. The present study focuses on an analysis and behavior of a monoleaf spring made of hybrid composite materials, i.e., carbon and E-glass fibers. It is observed that the natural frequency of a hybrid composite leaf spring is twice the frequency of a conventional leaf spring, particularly in the vertical direction, which means that the occurrences of resonance will be less. Also, it is observed that the stress produced in it is lower than that in a conventional leaf spring. The hybrid composite monoleaf spring proved to have better impact and tensile behavior than a steel one.

Group Interaction as a Vehicle to Facilitate Faculty-Student Advisement.

ERIC Educational Resources Information Center

Hutchins, David E.; Miller, William B.

1979-01-01

Faculty and upperclass students were trained in group techniques for freshman advising. The 144 advisees had fewer course and room changes, disciplinary referrals and suspensions, and less residence hall damage. They also returned as sophomores in greater numbers than students who experienced traditional advising. (Author)

Attractive and repulsive magnetic suspension systems overview

NASA Technical Reports Server (NTRS)

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.

Analysis of Train Suspension System Using MR dampers

NASA Astrophysics Data System (ADS)

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.

The development of a center cell structure in bonded aluminum for the Ferrari 408 research vehicle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seeds, A.; Nardini, D.; Cassese, F.

1989-01-01

In F408 research vehicle has enabled Ferrari Engineering to evaluate new forms of transmission, suspension, bodywork and structure for future production vehicles. As Alcan worked with Ferrari Engineering to adapt its Aluminum Structured Vehicle Technology (ASVT) to develop a bonded version of a central section of the structure (center cell). This paper begins with an outline of the major F408 project objectives and indicates the performance and manufacturing advantages for the features of interest, particularly the center cell structure. The paper describes the development stages of the bonded aluminum center cell. It shows that the performance and manufacturing objectives weremore » met with a substantial weight-saving and improvement in stiffness compared to laser-welded stainless steel. The paper concludes with a summary of the other technical innovations and developments in the F408 vehicle.« less

Antibacterial action of calcium hydroxide vehicles and calcium hydroxide pastes.

PubMed

Pacios, María Gabriela; Silva, Clara; López, María Elena; Cecilia, Marta

2012-11-01

To evaluate the in vitro action of vehicles alone and with calcium hydroxide against different bacterial species. Agar plates were inoculated with the microbial suspensions, and wells were made and filled with the calcium hydroxide pastes and the vehicles used to prepare the pastes. The zones of inhibited bacterial growth were recorded, and the resulting measurements were statistically analyzed. Enterococcus faecalis was the most resistant microorganism to all medicaments. Calcium hydroxide + p-monochlorophenol; calcium hydroxide + p-monochlorophenol-propylene glycol pastes; and p-monochlorophenol, p-monochlorophenol-propylene glycol, and chlorhexidine gluconate gel alone showed the largest zones of inhibition against all the tested microorganisms. The vehicle used to prepare the calcium hydroxide paste might contribute to its antibacterial action. Chlorhexidine gluconate gel used alone, and camphorated p-monochlorophenol and camphorated p-monochlorophenol-propylene glycol as vehicles of calcium hydroxide, could be recommended, in an antimicrobial sense. © 2012 Wiley Publishing Asia Pty Ltd.

Configuration Studies of Personal Air Vehicles. Personal Air Vehicle and Flying Jeep Concepts: A Commentary on Promising Approaches or What Goes Around Comes Around (About Every Twenty Years)

NASA Technical Reports Server (NTRS)

Hall, David W.

2001-01-01

The NASA/Langley Personal Air Vehicle (PAV) Exploration (PAVE) and the DARPA (Defense Advanced Research Projects Agency) Dual Air/Road Transportation System (DARTS) projects were established to investigate the feasibility of creating vehicles which could replace, or at the very least augment, personal ground and air transportation schemes. This overall goal implies integrating several technology areas with practical everyday transportation requirements to design a class of vehicles which will achieve the following goals: (1) Vertical, Extremely Short, or Short Takeoff and Landing (VTOL, ESTOL, STOL) capability; (2) Operation at block speeds markedly faster than current combinations of land and air transportation, particularly in critical market areas; (3) Unit cost comparable to current luxury cars and small general aviation aircraft; (4) Excellent reliability; (5) Excellent safety; (6) Ability to integrate with existing land and air transportation systems. The conclusions of these configuration studies are summarized as follows: (1) Creation of the five assigned configurations prompted added explorations, some of which were dead-ends; (2) Some components could be common to all configurations such as avionics and dual-mode suspension schemes; (3) Single-Mode PAVs can be created by removing dual-mode-specific items; (4) Aviation history provided some intriguing starting points, as in what goes around comes around; (5) CTOL (Conventional Take-off and Landing) and STOL dual-mode PAVs look feasible with single-mode PAVs being simplifications of the dual-mode approach; (6) VTOL PAVs will require development; (7) More exotic collapsing mechanisms mechanisms need development; (8) As a teaching tool, PAVs are not yet a well-enough bounded design problem.

Remotely detected vehicle mass from engine torque-induced frame twisting

NASA Astrophysics Data System (ADS)

McKay, Troy R.; Salvaggio, Carl; Faulring, Jason W.; Sweeney, Glenn D.

2017-06-01

Determining the mass of a vehicle from ground-based passive sensor data is important for many traffic safety requirements. This work presents a method for calculating the mass of a vehicle using ground-based video and acoustic measurements. By assuming that no energy is lost in the conversion, the mass of a vehicle can be calculated from the rotational energy generated by the vehicle's engine and the linear acceleration of the vehicle over a period of time. The amount of rotational energy being output by the vehicle's engine can be calculated from its torque and angular velocity. This model relates remotely observed, engine torque-induced frame twist to engine torque output using the vehicle's suspension parameters and engine geometry. The angular velocity of the engine is extracted from the acoustic emission of the engine, and the linear acceleration of the vehicle is calculated by remotely observing the position of the vehicle over time. This method combines these three dynamic signals; engine induced-frame twist, engine angular velocity, and the vehicle's linear acceleration, and three vehicle specific scalar parameters, into an expression that describes the mass of the vehicle. This method was tested on a semitrailer truck, and the results demonstrate a correlation of 97.7% between calculated and true vehicle mass.

Improving stability and curving passing performance for railway vehicles with a variable stiffness MRF rubber joint

NASA Astrophysics Data System (ADS)

Harris, B. J.; Sun, S. S.; Li, W. H.

2017-03-01

With the growing need for effective intercity transport, the need for more advanced rail vehicle technology has never been greater. The conflicting primary longitudinal suspension requirements of high speed stability and curving performance limit the development of rail vehicle technology. This paper presents a novel magnetorheological fluid based joint with variable stiffness characteristics for the purpose of overcoming this parameter conflict. Firstly, the joint design and working principle is developed. Following this, a prototype is tested by MTS to characterize its variable stiffness properties under a range of conditions. Lastly, the performance of the proposed MRF rubber joint with regard to improving train stability and curving performance is numerically evaluated.

Restructuring the Art of Health by Pharmacists: Formulation Designs with Oral Vehicles--Teaching Pharmacy Students.

PubMed

Benischek, Rita

2017-01-01

Compounding pharmacists, responsible for appropriate preparation of medications, coordinate with other professionals to reach optimal therapeutic options for patients. This review summarizes proprietary oral vehicles or suspensions focusing on available information or updated data from suppliers. Research has advanced methods with revised applications, cutting-edge safety considerations, beyond-use dating provisions for technical assistance, and evidence to review and teach pharmacy students the opportunities in the choices of an oral vehicle. Current marketing, competitive, and scientific trends necessitate that manufacturers shift further to research of product or integrated product mixes to sustain their independence in pharmacies. Copyright© by International Journal of Pharmaceutical Compounding, Inc.

An evaluation of the specific deterrent effect of vehicle impoundment on suspended, revoked and unlicensed drivers in California

DOT National Transportation Integrated Search

1997-11-01

While license suspension has been shown to be effective, many drivers with suspended (S) or revoked (R) licenses continue to drive illegally, collecting additional citations and becoming involved in crashes. To reduce the occurrence of driving by off...

An evaluation of the general deterrent effect of vehicle impoundment on suspended and revoked drivers in California

DOT National Transportation Integrated Search

2000-04-01

While license suspension/revocation have been shown to be effective, it is also known that most suspended/revoked (S/R) drivers violate their S/R order and continue to drive, accruing traffic convictions and becoming involved in crashes. In an attemp...

Preliminary analysis of the effects of non-linear creep and flange contact forces on truck performance in curves

DOT National Transportation Integrated Search

1975-05-31

Prediction of wheel displacements and wheel-rail forces is a prerequisite to the evaluation of the curving performance of rail vehicles. This information provides part of the basis for the rational design of wheels and suspension components, for esta...

49 CFR 581.6 - Conditions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... the vehicle if they are optional equipment. (b) Pendulum test conditions. The following conditions apply to the pendulum test procedures of § 581.7 (a) and (b). (1) The test device consists of a block... 1963. From the point of release of the device until the onset of rebound, the pendulum suspension...

49 CFR 581.6 - Conditions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... the vehicle if they are optional equipment. (b) Pendulum test conditions. The following conditions apply to the pendulum test procedures of § 581.7 (a) and (b). (1) The test device consists of a block... 1963. From the point of release of the device until the onset of rebound, the pendulum suspension...

49 CFR 581.6 - Conditions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... the vehicle if they are optional equipment. (b) Pendulum test conditions. The following conditions apply to the pendulum test procedures of § 581.7 (a) and (b). (1) The test device consists of a block... 1963. From the point of release of the device until the onset of rebound, the pendulum suspension...

49 CFR 581.6 - Conditions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... the vehicle if they are optional equipment. (b) Pendulum test conditions. The following conditions apply to the pendulum test procedures of § 581.7 (a) and (b). (1) The test device consists of a block... 1963. From the point of release of the device until the onset of rebound, the pendulum suspension...

49 CFR 581.6 - Conditions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... the vehicle if they are optional equipment. (b) Pendulum test conditions. The following conditions apply to the pendulum test procedures of § 581.7 (a) and (b). (1) The test device consists of a block... 1963. From the point of release of the device until the onset of rebound, the pendulum suspension...

Rule-Based Motion Coordination for the Adaptive Suspension Vehicle on Ternary-Type Terrain

DTIC Science & Technology

1990-12-01

robot-window-array* nil) (defvar *robot..window..width* nil) (defvar * rebot -.window..heig)ht* nil) (defvar *terrain-buffer* nil) (defvar *terrain...cond ((momrber leg lift-able-leg. -test #’equal) log) (t nil)) .(dafmethod (test-overlap- rebot ipltcable-leg) (log) (nond ((and (member leg place-able

23 CFR 1225.3 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-04-01

... above a specified level. (e) Citations to State law means citations to all sections of the State's law... suspension. (c) BAC means either blood or breath alcohol concentration. (d) BAC per se law means a law that... begun to implement the law. (g) Operating a motor vehicle means driving or being in actual physical...

Stability study of oral pediatric idebenone suspensions.

PubMed

Schlatter, Joël; Bourguignon, Elodie; Majoul, Elyes; Kabiche, Sofiane; Balde, Issa-Bella; Cisternino, Salvatore; Fontan, Jean-Eudes

2017-03-01

Adapted forms for administration to infants are limited. The proposed study was performed to propose oral liquid formulations of idebenone in Ora-Plus and either Ora-Sweet or Ora-Sweet SF, Ora-Blend, Ora-Blend SF and Inorpha. Each formulation was stored in 30 ml amber glass bottle at 5 or 25 °C for 90 days. Idebenone contents in these suspensions, determined by a stability-indicating high-performance liquid chromatography method, remained stable at least 90 days in Inorpha when stored at the two temperatures. In Ora-Blend, the stability was estimated at 14 days and in other suspensions at 20 days at the two temperatures. After 90 days storage, the pH of Ora-Plus and Ora-Sweet or Ora-Sweet SF changed between -0.10 and -0.25 units. For others suspensions, the pH changes were not significant (< -0.09 unit). No change was observed in color, odor or visual microbiology. To conclude, we recommended the use of idebenone in Inorpha vehicle stable for at least 90 days at 25 °C.

Composite structural armor for combat vehicle applications

NASA Technical Reports Server (NTRS)

Haskell, William E., III; Alesi, A. L.; Parsons, G. R.

1990-01-01

Several projects that have demonstrated the advantages of using thick composite armor technology for structural applications in armored combat vehicles are discussed. The first involved composite cargo doors for the Marine Corps LVTP-7 amphibious landing vehicle. Another was a demonstration composite turret that offered a weight reduction of 15.5 percent. The advantages of this composite armor compared to metallic armors used for combat vehicle hull and turret applications are reduced weight at equal ballistic protection; reduced back armor spall; excellent corrosion resistance; reduced production costs by parts consolidation; and inherent thermal and acoustic insulative properties. Based on the encouraging results of these past programs, the Demonstration Composite Hull Program was started in September 1986. To demonstrate this composite armor technology, the Army's newest infantry fighting vehicle, the Bradley Fighting Vehicle (BFV), was selected as a model. A composite infantry fighting vehicle, designated the CIFV for this program, has been designed and fabricated and is currently undergoing a 6000 mile field endurance test. The CIFV demonstration vehicle uses the BFV engine, transmission, suspension, track and other equipment.

Method of determining operation parameters of stand tests of vehicle suspension elements under conditions of ultra-low temperatures

NASA Astrophysics Data System (ADS)

Fedyanov, E. A.; Sokolov-Dobrev, N. S.; Ljashenko, M. V.; Shekhovtsov, V. V.; Potapov, P. V.; Dolotov, A. A.; Klementiev, E. V.

2018-05-01

This article presents the description of the method for estimation of heat flows characteristic during research of operability of suspension elements under the conditions of ultralow temperature. The mentioned research is performed at the test bench created in VSTU. Solid carbon dioxide (also known as artificial ice) is used as the coolant. The method provides evaluation of required quantity of artificial ice and cooling dynamics of the test unit in the insulated low-temperature chamber with structurally specified parameters of heat insulation. Also the method allows computation of heat intake into the chamber volume.

Haptic seat for fuel economy feedback

DOEpatents

Bobbitt, III, John Thomas

2016-08-30

A process of providing driver fuel economy feedback is disclosed in which vehicle sensors provide for haptic feedback on fuel usage. Such sensors may include one or more of a speed sensors, global position satellite units, vehicle pitch/roll angle sensors, suspension displacement sensors, longitudinal accelerometer sensors, throttle position in sensors, steering angle sensors, break pressure sensors, and lateral accelerometer sensors. Sensors used singlely or collectively can provide enhanced feedback as to various environmental conditions and operating conditions such that a more accurate assessment of fuel economy information can be provided to the driver.

Magnetic suspension and balance systems (MSBSs)

NASA Technical Reports Server (NTRS)

Britcher, Colin P.; Kilgore, Robert A.

1987-01-01

The problems of wind tunnel testing are outlined, with attention given to the problems caused by mechanical support systems, such as support interference, dynamic-testing restrictions, and low productivity. The basic principles of magnetic suspension are highlighted, along with the history of magnetic suspension and balance systems. Roll control, size limitations, high angle of attack, reliability, position sensing, and calibration are discussed among the problems and limitations of the existing magnetic suspension and balance systems. Examples of the existing systems are presented, and design studies for future systems are outlined. Problems specific to large-scale magnetic suspension and balance systems, such as high model loads, requirements for high-power electromagnets, high-capacity power supplies, highly sophisticated control systems and position sensors, and high costs are assessed.

Progress towards extreme attitude testing with Magnetic Suspension and Balance Systems

NASA Technical Reports Server (NTRS)

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.

Nose-to-brain transport of melatonin from polymer gel suspensions: a microdialysis study in rats.

PubMed

Jayachandra Babu, R; Dayal, Pankaj Patrick; Pawar, Kasturi; Singh, Mandip

2011-11-01

Exogenous melatonin (MT) has significant neuroprotective roles in Alzheimer's and Parkinson's diseases. This study investigates the delivery MT to brain via nasal route as a polymeric gel suspension using central brain microdialysis in anesthetized rats. Micronized MT suspensions using polymers [carbopol, carboxymethyl cellulose (CMC)] and polyethylene glycol 400 (PEG400) were prepared and characterized for nasal administration. In vitro permeation of the formulations was measured across a three-dimensional tissue culture model EpiAirway(™). The central brain delivery into olfactory bulb of nasally administered MT gel suspensions was studied using brain microdialysis in male Wistar rats. The MT content of microdialysis samples was analyzed by high performance liquid chromatography (HPLC) using electrochemical detection. The nose-to-brain delivery of MT formulations was compared with intravenously administered MT solution. MT suspensions in carbopol and CMC vehicles have shown significantly higher permeability across Epiairway(™) as compared to control, PEG400 (P < 0.05). The brain (olfactory bulb) levels of MT after intranasal administration were 9.22, 6.77 and 4.04-fold higher for carbopol, CMC and PEG400, respectively, than that of intravenous MT in rats. In conclusion, microdialysis studies demonstrated increased brain levels of MT via nasal administration in rats.

Physical and Chemical Stability of Budesonide Mucoadhesive Oral Suspensions (MucoLox).

PubMed

Ip, Kendice; Carvalho, Maria; Shan, Ashley; Banov, Daniel

2017-01-01

Budesonide is a corticosteroid that has been shown effective in the treatment of eosinophilic esophagitis, but there are currently no commercial medicines to treat this chronic allergic/immune condition, despite its prevalence in the U.S. Therefore, pharmaceutical compounding is the alternative choice to meet the therapeutic need of eosinophilic esophagitis patients. Two budesonide mucoadhesive oral suspensions (1 mg/10 mL and 2 mg/10 mL) were developed using the compounding vehicle MucoLox, a proprietary mucoadhesive polymer blend that promotes mucosal adhesion. The physical and chemical stability of the oral suspensions was tested over a period of 182 days, at room temperature and refrigerated conditions, in order to determine the corresponding beyond-use date. The physical characterization consisted in observing all samples for color/appearance and odor, and testing for pH and density, whereas the chemical characterization consisted in ultra-performance liquid chromatography assay testing. Both oral suspensions were proven physically and chemically stable, and the ultra-performance liquid chromatography method was proven stability indicating. As a result, the beyond-use date of the budesonide 1-mg/10-mL and 2-mg/10-mL mucoadhesive oral suspensions (MucoLox), in amber plastic bottles, is six months at both room temperature and refrigerated conditions. Copyright© by International Journal of Pharmaceutical Compounding, Inc.

Nose-to-brain transport of melatonin from polymer gel suspensions: a microdialysis study in rats

PubMed Central

Babu, R. Jayachandra; Dayal, Pankaj Patrick; Pawar, Kasturi; Singh, Mandip

2012-01-01

Purpose Exogenous melatonin (MT) has significant neuroprotective roles in Alzheimer’s and Parkinson’s diseases. This study investigates the delivery MT to brain via nasal route as a polymeric gel suspension using central brain microdialysis in anesthetized rats. Methods Micronized MT suspensions using polymers [carbopol, carboxymethyl cellulose (CMC)] and polyethylene glycol 400 (PEG400) were prepared and characterized for nasal administration. In vitro permeation of the formulations was measured across a three-dimensional tissue culture model EpiAirway™. The central brain delivery into olfactory bulb of nasally administered MT gel suspensions was studied using brain microdialysis in male Wistar rats. The MT content of microdialysis samples was analyzed by high performance liquid chromatography (HPLC) using electrochemical detection. The nose-to-brain delivery of MT formulations was compared with intravenously administered MT solution. Results MT suspensions in carbopol and CMC vehicles have shown significantly higher permeability across Epiairway™ as compared to control, PEG400 (P < 0.05). The brain (olfactory bulb) levels of MT after intranasal administration were 9.22, 6.77 and 4.04-fold higher for carbopol, CMC and PEG400, respectively, than that of intravenous MT in rats. In conclusion, microdialysis studies demonstrated increased brain levels of MT via nasal administration in rats. PMID:21428693

Transtibial prosthesis suspension systems: systematic review of literature.

PubMed

Gholizadeh, H; Abu Osman, N A; Eshraghi, A; Ali, S; Razak, N A

2014-01-01

Today a number of prosthetic suspension systems are available for transtibial amputees. Consideration of an appropriate suspension system can ensure that amputee's functional needs are satisfied. The higher the insight to suspension systems, the easier would be the selection for prosthetists. This review attempted to find scientific evidence pertaining to various transtibial suspension systems to provide selection criteria for clinicians. Databases of PubMed, Web of Science, and ScienceDirect were explored to find related articles. Search terms were as follows: "Transtibial prosthesis (32), prosthetic suspension (48), lower limb prosthesis (54), below-knee prosthesis (58), prosthetic liner (20), transtibial (193), and prosthetic socket (111)". Two reviewers separately examined the papers. Study design (case series of five or more subjects, retrospective or prospective), research instrument, sampling method, outcome measures and protocols were reviewed. Based on the selection criteria, 22 articles (15 prospective studies, and 7 surveys) remained. Sweat control was found to be a major concern with the available suspension liners. Donning and doffing procedures for soft liners are also problematic for some users, particularly those with upper limb weakness. Moreover, the total surface bearing (TSB) socket with pin/lock system is favored by the majority of amputees. In summary, no clinical evidence is available to suggest what kind of suspension system could have an influential effect as a "standard" system for all transtibial amputees. However, among various suspension systems for transtibial amputees, the Iceross system was favored by the majority of users in terms of function and comfort. © 2013. Published by Elsevier Ltd. All rights reserved.

Computation of magnetic suspension of maglev systems using dynamic circuit theory

NASA Technical Reports Server (NTRS)

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.

Development of a Single High Fat Meal Challenge to Unmask ...

EPA Pesticide Factsheets

Stress tests are used clinically to determine the presence of underlying disease and predict future cardiovascular risk. In previous studies, we used treadmill exercise stress in rats to unmask the priming effects of air pollution inhalation. Other day-to-day activities stress the cardiovascular system, and when modeled experimentally, may be useful in identifying latent effects of air pollution exposure. For example, a single high fat (HF) meal can cause transient vascular endothelial dysfunction and increases in LDL cholesterol, triglycerides (TG), oxidative stress, and inflammation. Given the prevalence of HF meals in western diets, the goal of this study was to develop a HF meal challenge in rats to see if air pollution primes the body for a subsequent stress-induced adverse response. Healthy male Wistar Kyoto rats were fasted for six hours and then administered a single oral gavage of isocaloric lard-based HF or low fat (LF) suspensions, or a water vehicle control. We hypothesized that rats given a HF load would elicit postprandial changes in cardiopulmonary function that were distinct from LF and vehicle controls. One to four hours after gavage, rats underwent whole body plethysmography to assess breathing patterns, cardiovascular ultrasounds, blood draws for measurements of systemic lipids and hormones and a test for sensitivity to aconitine-induced arrhythmia. HF gavage caused an increase in circulating TG relative to LF and vehicle controls and an incre

Evaluation of the Impact of Excipients and an Albendazole Salt on Albendazole Concentrations in Upper Small Intestine Using an In Vitro Biorelevant Gastrointestinal Transfer (BioGIT) System.

PubMed

Kourentas, Alexandros; Vertzoni, Maria; Khadra, Ibrahim; Symillides, Mira; Clark, Hugh; Halbert, Gavin; Butler, James; Reppas, Christos

2016-09-01

An in vitro biorelevant gastrointestinal transfer (BioGIT) system was assessed for its ability to mimic recently reported albendazole concentrations in human upper small intestine after administration of free base suspensions to fasted adults in absence and in presence of supersaturation promoting excipients (hydroxypropylmethylcellulose and lipid self-emulsifying vehicles). The in vitro method was also used to evaluate the likely impact of using the sulfate salt on albendazole concentrations in upper small intestine. In addition, BioGIT data were compared with equilibrium solubility data of the salt and the free base in human aspirates and biorelevant media. The BioGIT system adequately simulated the average albendazole gastrointestinal transfer process and concentrations in upper small intestine after administration of the free base suspensions to fasted adults. However, the degree of supersaturation observed in the duodenal compartment was greater than in vivo. Albendazole sulfate resulted in minimal increase of albendazole concentrations in the duodenal compartment of the BioGIT, despite improved equilibrium solubility observed in human aspirates and biorelevant media, indicating that the use of a salt is unlikely to lead to any significant oral absorption advantage for albendazole. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Design and characterization of submicron formulation for a poorly soluble drug: the effect of Vitamin E TPGS and other solubilizers on skin permeability enhancement.

PubMed

Ghosh, Indrajit; Michniak-Kohn, Bozena

2012-09-15

In transdermal drug delivery systems (TDDS), it is a challenge to achieve stable and prolonged high permeation rates across the skin since the concentrations of the drug dissolved in the matrix have to be high in order to maintain zero order release kinetics. Several attempts have been reported to improve the permeability of poorly soluble drug compounds using supersaturated systems, however, due to thermodynamic challenges, there was a high tendency for the drug to nucleate immediately after formulating or even during storage. The present study focuses on the efficiency of drug crystals at the submicron/nano range in presence of different solubilizers to improve the permeation rate. Effect of several solubilizers, e.g. Pluronic F-127, Vitamin E TPGS, propylene glycol were studied on the submicron suspension systems of ibuprofen as a model drug. Various stabilizers such as hydroxylpropyl methylcellulose (HPMC) and polyvinylpyrrolidone (PVP) were examined to evaluate their crystal inhibitory effects on particle growth of the drug compound at submicron range. The overall permeation enhancement process through the skin seems to be influenced by the presence of solubilizers and also the presence of submicron drug crystal. The most promising stable formulation was developed with Vitamin E TPGS+HPMC submicron suspension, which produced higher permeation rate compared to other vehicles. Copyright © 2012 Elsevier B.V. All rights reserved.

The application of high-speed TV-holography to time-resolved vibration measurements

NASA Astrophysics Data System (ADS)

Buckberry, C.; Reeves, M.; Moore, A. J.; Hand, D. P.; Barton, J. S.; Jones, J. D. C.

1999-10-01

We describe an electronic speckle pattern interferometer (ESPI) system that has enabled non-harmonic vibrations to be measured with μs temporal resolution. The short exposure period and high framing rate of a high-speed camera at up to 40,500 frames per second allow low-power CW laser illumination and fibre-optic beam delivery to be used, rather than the high peak power pulsed lasers normally used in ESPI for transient measurement. The technique has been demonstrated in the laboratory and tested in preliminary industrial trials. The ability to measure vibration with high spatial and temporal resolution, which is not provided by techniques such as scanning laser vibrometry, has many applications in manufacturing design, and in an illustrative application described here revealed previously unmeasured “rocking” vibrations of a car door. It has been possible to make the measurement on the door as part of a complete vehicle standing on its own tyres, wheels and suspension, and where the excitation was generated by the running of the vehicle's own engine.

System and technique for ultrasonic characterization of settling suspensions

DOEpatents

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.

Equations of motion of the lunar roving vehicle.

NASA Technical Reports Server (NTRS)

Kaufman, S.

1973-01-01

Equations of motion have been formulated for a four-wheel vehicle as it traverses a terrain characterized by slopes, craters, bumps, washboards, or a power spectrum. Independent suspension and electric motor propulsion are considered. These equations were programmed on the UNIVAC 1108 digital computer. Results are given for the steerability of the Lunar Roving Vehicle (LRV) which was found to be satisfactory for normal operating speeds and turning radii. The vehicle was also found to be satisfactory against overturning in both the pitch and roll mode, and results are presented for various speeds as the LRV engages a bump on meter in diameter and of varying heights. Speed, power consumption, and load characteristics are presented for the LRV traversing a simulated lunar soil at full throttle. Comparisons are given against data compiled from the Apollo 15 mission.

Nonlinear analysis of switched semi-active controlled systems

NASA Astrophysics Data System (ADS)

Eslaminasab, Nima; Vahid A., Orang; Golnaraghi, Farid

2011-02-01

Semi-active systems improve suspension performance of the vehicles more effectively than conventional passive systems by simultaneously improving ride comfort and road handling. Also, because of size, weight, price and performance advantages, they have gained more interest over the active as well as passive systems. Probably the most neglected aspect of the semi-active on-off control systems and strategies is the effects of the added nonlinearities of those systems, which are introduced and analysed in this paper. To do so, numerical techniques, analytical method of averaging and experimental analysis are deployed. In this paper, a new method to analyse, calculate and compare the performances of the semi-active controlled systems is proposed; further, a new controller based on the observations of actual test data is proposed to eliminate the adverse effects of added nonlinearities. The significance of the proposed new system is the simplicity of the algorithm and ease of implementation. In fact, this new semi-active control strategy could be easily adopted and used with most of the existing semi-active control systems.

49 CFR 393.207 - Suspension systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... bar. No torsion bar or torsion bar suspension shall be cracked or broken. (f) Air suspensions. The air... the controls are either located on the trailer, or the power unit and trailer combination are not....207 Suspension systems. (a) Axles. No axle positioning part shall be cracked, broken, loose or missing...

48 CFR 423.506 - Suspension of payments, termination of contract, and debarment and suspension actions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 4 2014-10-01 2014-10-01 false Suspension of payments, termination of contract, and debarment and suspension actions. 423.506 Section 423.506 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE SOCIOECONOMIC PROGRAMS ENVIRONMENT, ENERGY AND WATER EFFICIENCY...

48 CFR 423.506 - Suspension of payments, termination of contract, and debarment and suspension actions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Suspension of payments, termination of contract, and debarment and suspension actions. 423.506 Section 423.506 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE SOCIOECONOMIC PROGRAMS ENVIRONMENT, ENERGY AND WATER EFFICIENCY...

48 CFR 423.506 - Suspension of payments, termination of contract, and debarment and suspension actions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 4 2011-10-01 2011-10-01 false Suspension of payments, termination of contract, and debarment and suspension actions. 423.506 Section 423.506 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE SOCIOECONOMIC PROGRAMS ENVIRONMENT, ENERGY AND WATER EFFICIENCY...

48 CFR 423.506 - Suspension of payments, termination of contract, and debarment and suspension actions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 4 2013-10-01 2013-10-01 false Suspension of payments, termination of contract, and debarment and suspension actions. 423.506 Section 423.506 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE SOCIOECONOMIC PROGRAMS ENVIRONMENT, ENERGY AND WATER EFFICIENCY...

48 CFR 423.506 - Suspension of payments, termination of contract, and debarment and suspension actions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 4 2012-10-01 2012-10-01 false Suspension of payments, termination of contract, and debarment and suspension actions. 423.506 Section 423.506 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE SOCIOECONOMIC PROGRAMS ENVIRONMENT, ENERGY AND WATER EFFICIENCY...

Performance Analysis of a Semiactive Suspension System with Particle Swarm Optimization and Fuzzy Logic Control

PubMed Central

Qazi, Abroon Jamal; de Silva, Clarence W.

2014-01-01

This paper uses a quarter model of an automobile having passive and semiactive suspension systems to develop a scheme for an optimal suspension controller. Semi-active suspension is preferred over passive and active suspensions with regard to optimum performance within the constraints of weight and operational cost. A fuzzy logic controller is incorporated into the semi-active suspension system. It is able to handle nonlinearities through the use of heuristic rules. Particle swarm optimization (PSO) is applied to determine the optimal gain parameters for the fuzzy logic controller, while maintaining within the normalized ranges of the controller inputs and output. The performance of resulting optimized system is compared with different systems that use various control algorithms, including a conventional passive system, choice options of feedback signals, and damping coefficient limits. Also, the optimized semi-active suspension system is evaluated for its performance in relation to variation in payload. Furthermore, the systems are compared with respect to the attributes of road handling and ride comfort. In all the simulation studies it is found that the optimized fuzzy logic controller surpasses the other types of control. PMID:24574868

A comparison of dispersing media for various engineered carbon nanoparticles

PubMed Central

Buford, Mary C; Hamilton, Raymond F; Holian, Andrij

2007-01-01

Background With the increased manufacture and use of carbon nanoparticles (CNP) there has been increasing concern about the potential toxicity of fugitive CNP in the workplace and ambient environment. To address this matter a number of investigators have conducted in vitro and in vivo toxicity assessments. However, a variety of different approaches for suspension of these particles (culture media, Tween 80, dimethyl sulfoxide, phosphate-buffered saline, fetal calf serum, and others), and different sources of materials have generated potentially conflicting outcomes. The quality of the dispersion of nanoparticles is very dependent on the medium used to suspend them, and this then will most likely affect the biological outcomes. Results In this work, the distributions of different CNP (sources and types) have been characterized in various media. Furthermore, the outcome of instilling the different agglomerates, or size distributions, was examined in mouse lungs after one and seven days. Our results demonstrated that CNP suspended in serum produced particle suspensions with the fewest large agglomerates, and the most uniform distribution in mouse lungs. In addition, no apparent clearance of instilled CNP took place from lungs even after seven days. Conclusion This work demonstrates that CNP agglomerates are present in all dispersing vehicles to some degree. The vehicle that contains some protein, lipid or protein/lipid component disperses the CNP best, producing fewer large CNP agglomerates. In contrast, vehicles absent of lipid and protein produce the largest CNP agglomerates. The source of the CNP is also a factor in the degree of particle agglomeration within the same vehicle. PMID:17655771