Analysis on the multi-dimensional spectrum of the thrust force for the linear motor feed drive system in machine tools

NASA Astrophysics Data System (ADS)

Yang, Xiaojun; Lu, Dun; Ma, Chengfang; Zhang, Jun; Zhao, Wanhua

2017-01-01

The motor thrust force has lots of harmonic components due to the nonlinearity of drive circuit and motor itself in the linear motor feed drive system. What is more, in the motion process, these thrust force harmonics may vary with the position, velocity, acceleration and load, which affects the displacement fluctuation of the feed drive system. Therefore, in this paper, on the basis of the thrust force spectrum obtained by the Maxwell equation and the electromagnetic energy method, the multi-dimensional variation of each thrust harmonic is analyzed under different motion parameters. Then the model of the servo system is established oriented to the dynamic precision. The influence of the variation of the thrust force spectrum on the displacement fluctuation is discussed. At last the experiments are carried out to verify the theoretical analysis above. It can be found that the thrust harmonics show multi-dimensional spectrum characteristics under different motion parameters and loads, which should be considered to choose the motion parameters and optimize the servo control parameters in the high-speed and high-precision machine tools equipped with the linear motor feed drive system.

Jack mechanism having positive stop means for its crank handle

NASA Astrophysics Data System (ADS)

Crockett, Watkins, IV; Baird, Bernard W.

1995-04-01

A jack mechanism having a crank handle that drives a linear motion control ball nut and threaded screw is presented. Two rods are included to provide a positive stop in each direction of the jack's limit so as to prevent overrun of the mechanism.

Article mounting and position adjustment stage

DOEpatents

Cutburth, R.W.; Silva, L.L.

1988-05-10

An improved adjustment and mounting stage of the type used for the detection of laser beams is disclosed. A ring sensor holder has locating pins on a first side thereof which are positioned within a linear keyway in a surrounding housing for permitting reciprocal movement of the ring along the keyway. A rotatable ring gear is positioned within the housing on the other side of the ring from the linear keyway and includes an oval keyway which drives the ring along the linear keyway upon rotation of the gear. Motor-driven single-stage and dual (x, y) stage adjustment systems are disclosed which are of compact construction and include a large laser transmission hole. 6 figs.

Article mounting and position adjustment stage

DOEpatents

Cutburth, Ronald W.; Silva, Leonard L.

1988-01-01

An improved adjustment and mounting stage of the type used for the detection of laser beams is disclosed. A ring sensor holder has locating pins on a first side thereof which are positioned within a linear keyway in a surrounding housing for permitting reciprocal movement of the ring along the keyway. A rotatable ring gear is positioned within the housing on the other side of the ring from the linear keyway and includes an oval keyway which drives the ring along the linear keyway upon rotation of the gear. Motor-driven single-stage and dual (x, y) stage adjustment systems are disclosed which are of compact construction and include a large laser transmission hole.

Identification and compensation of friction for a novel two-axis differential micro-feed system

NASA Astrophysics Data System (ADS)

Du, Fuxin; Zhang, Mingyang; Wang, Zhaoguo; Yu, Chen; Feng, Xianying; Li, Peigang

2018-06-01

Non-linear friction in a conventional drive feed system (CDFS) feeding at low speed is one of the main factors that lead to the complexity of the feed drive. The CDFS will inevitably enter or approach a non-linear creeping work area at extremely low speed. A novel two-axis differential micro-feed system (TDMS) is developed in this paper to overcome the accuracy limitation of CDFS. A dynamic model of TDMS is first established. Then, a novel all-component friction parameter identification method (ACFPIM) using a genetic algorithm (GA) to identify the friction parameters of a TDMS is introduced. The friction parameters of the ball screw and linear motion guides are identified independently using the method, assuring the accurate modelling of friction force at all components. A proportional-derivate feed drive position controller with an observer-based friction compensator is implemented to achieve an accurate trajectory tracking performance. Finally, comparative experiments demonstrate the effectiveness of the TDMS in inhibiting the disadvantageous influence of non-linear friction and the validity of the proposed identification method for TDMS.

Final Report: CNC Micromachines LDRD No.10793

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

JOKIEL JR., BERNHARD; BENAVIDES, GILBERT L.; BIEG, LOTHAR F.

2003-04-01

The three-year LDRD ''CNC Micromachines'' was successfully completed at the end of FY02. The project had four major breakthroughs in spatial motion control in MEMS: (1) A unified method for designing scalable planar and spatial on-chip motion control systems was developed. The method relies on the use of parallel kinematic mechanisms (PKMs) that when properly designed provide different types of motion on-chip without the need for post-fabrication assembly, (2) A new type of actuator was developed--the linear stepping track drive (LSTD) that provides open loop linear position control that is scalable in displacement, output force and step size. Several versionsmore » of this actuator were designed, fabricated and successfully tested. (3) Different versions of XYZ translation only and PTT motion stages were designed, successfully fabricated and successfully tested demonstrating absolutely that on-chip spatial motion control systems are not only possible, but are a reality. (4) Control algorithms, software and infrastructure based on MATLAB were created and successfully implemented to drive the XYZ and PTT motion platforms in a controlled manner. The control software is capable of reading an M/G code machine tool language file, decode the instructions and correctly calculate and apply position and velocity trajectories to the motion devices linear drive inputs to position the device platform along the trajectory as specified by the input file. A full and detailed account of design methodology, theory and experimental results (failures and successes) is provided.« less

Control system to reduce the effects of friction in drive trains of continuous-path-positioning systems. [Patent application

DOEpatents

Green, W.L.

1980-12-01

An improved continuous-path-positioning servo-control system is provided for reducing the effects of friction arising at very low cutting speeds in the drive trains of numerically controlled cutting machines, and the like. The improvement comprises a feed forward network for altering the gain of the servo-control loop at low positioning velocities to prevent stick-slip movement of the cutting tool holder being positioned by the control system. The feed forward network shunts conventional lag-compensators in the control loop, or loops, so that the error signal used for positioning varies linearly when the value is small, but being limited for larger values. Thus, at higher positioning speeds there is little effect of the added component upon the control being achieved.

Focus drive mechanism for the IUE scientific instrument

NASA Technical Reports Server (NTRS)

Devine, E. J.; Dennis, T. B., Jr.

1977-01-01

A compact, lightweight mechanism was developed for in-orbit adjustment of the position of the secondary mirror (focusing) of the International Ultraviolet Explored telescope. This device is a linear drive with small (.0004 in.) and highly repeatable step increments. Extremely close tolerances are also held in tilt and decentering. The unique mechanization is described with attention to the design details that contribute to positional accuracy. Lubrication, materials, thermal considerations, sealing, detenting against launch loads, and other features peculiar to flight hardware are discussed. The methods employed for mounting the low expansion quartz mirror with minimum distortion are also given.

Linear Back-Drive Differentials

NASA Technical Reports Server (NTRS)

Waydo, Peter

2003-01-01

Linear back-drive differentials have been proposed as alternatives to conventional gear differentials for applications in which there is only limited rotational motion (e.g., oscillation). The finite nature of the rotation makes it possible to optimize a linear back-drive differential in ways that would not be possible for gear differentials or other differentials that are required to be capable of unlimited rotation. As a result, relative to gear differentials, linear back-drive differentials could be more compact and less massive, could contain fewer complex parts, and could be less sensitive to variations in the viscosities of lubricants. Linear back-drive differentials would operate according to established principles of power ball screws and linear-motion drives, but would utilize these principles in an innovative way. One major characteristic of such mechanisms that would be exploited in linear back-drive differentials is the possibility of designing them to drive or back-drive with similar efficiency and energy input: in other words, such a mechanism can be designed so that a rotating screw can drive a nut linearly or the linear motion of the nut can cause the screw to rotate. A linear back-drive differential (see figure) would include two collinear shafts connected to two parts that are intended to engage in limited opposing rotations. The linear back-drive differential would also include a nut that would be free to translate along its axis but not to rotate. The inner surface of the nut would be right-hand threaded at one end and left-hand threaded at the opposite end to engage corresponding right- and left-handed threads on the shafts. A rotation and torque introduced into the system via one shaft would drive the nut in linear motion. The nut, in turn, would back-drive the other shaft, creating a reaction torque. Balls would reduce friction, making it possible for the shaft/nut coupling on each side to operate with 90 percent efficiency.

Mortality and pulmonary mechanics in relation to respiratory system and transpulmonary driving pressures in ARDS.

PubMed

Baedorf Kassis, Elias; Loring, Stephen H; Talmor, Daniel

2016-08-01

The driving pressure of the respiratory system has been shown to strongly correlate with mortality in a recent large retrospective ARDSnet study. Respiratory system driving pressure [plateau pressure-positive end-expiratory pressure (PEEP)] does not account for variable chest wall compliance. Esophageal manometry can be utilized to determine transpulmonary driving pressure. We have examined the relationships between respiratory system and transpulmonary driving pressure, pulmonary mechanics and 28-day mortality. Fifty-six patients from a previous study were analyzed to compare PEEP titration to maintain positive transpulmonary end-expiratory pressure to a control protocol. Respiratory system and transpulmonary driving pressures and pulmonary mechanics were examined at baseline, 5 min and 24 h. Analysis of variance and linear regression were used to compare 28 day survivors versus non-survivors and the intervention group versus the control group, respectively. At baseline and 5 min there was no difference in respiratory system or transpulmonary driving pressure. By 24 h, survivors had lower respiratory system and transpulmonary driving pressures. Similarly, by 24 h the intervention group had lower transpulmonary driving pressure. This decrease was explained by improved elastance and increased PEEP. The results suggest that utilizing PEEP titration to target positive transpulmonary pressure via esophageal manometry causes both improved elastance and driving pressures. Treatment strategies leading to decreased respiratory system and transpulmonary driving pressure at 24 h may be associated with improved 28 day mortality. Studies to clarify the role of respiratory system and transpulmonary driving pressures as a prognosticator and bedside ventilator target are warranted.

Control System for Prosthetic Devices

NASA Technical Reports Server (NTRS)

Bozeman, Richard J. (Inventor)

1996-01-01

A control system and method for prosthetic devices is provided. The control system comprises a transducer for receiving movement from a body part for generating a sensing signal associated with that of movement. The sensing signal is processed by a linearizer for linearizing the sensing signal to be a linear function of the magnitude of the distance moved by the body part. The linearized sensing signal is normalized to be a function of the entire range of body part movement from the no-shrug position of the moveable body part through the full-shrg position of the moveable body part. The normalized signal is divided into a plurality of discrete command signals. The discrete command signals are used by typical converter devices which are in operational association with the prosthetic device. The converter device uses the discrete command signals for driving the moveable portions of the prosthetic device and its sub-prosthesis. The method for controlling a prosthetic device associated with the present invention comprises the steps of receiving the movement from the body part, generating a sensing signal in association with the movement of the body part, linearizing the sensing signal to be a linear function of the magnitude of the distance moved by the body part, normalizing the linear signal to be a function of the entire range of the body part movement, dividing the normalized signal into a plurality of discrete command signals, and implementing the plurality of discrete command signals for driving the respective moveable prosthesis device and its sub-prosthesis.

Control system and method for prosthetic devices

NASA Technical Reports Server (NTRS)

Bozeman, Richard J., Jr. (Inventor)

1992-01-01

A control system and method for prosthetic devices is provided. The control system comprises a transducer for receiving movement from a body part for generating a sensing signal associated with that movement. The sensing signal is processed by a linearizer for linearizing the sensing signal to be a linear function of the magnitude of the distance moved by the body part. The linearized sensing signal is normalized to be a function of the entire range of body part movement from the no-shrug position of the movable body part through the full-shrug position of the movable body part. The normalized signal is divided into a plurality of discrete command signals. The discrete command signals are used by typical converter devices which are in operational association with the prosthetic device. The converter device uses the discrete command signals for driving the movable portions of the prosthetic device and its sub-prosthesis. The method for controlling a prosthetic device associated with the present invention comprises the steps of receiving the movement from the body part, generating a sensing signal in association with the movement of the body part, linearizing the sensing signal to be a linear function of the magnitude of the distance moved by the body part, normalizing the linear signal to be a function of the entire range of the body part movement, dividing the normalized signal into a plurality of discrete command signals, and implementing the plurality of discrete command signals for driving the respective movable prosthesis device and its sub-prosthesis.

Linear motion device and method for inserting and withdrawing control rods

DOEpatents

Smith, Jay E.

1984-01-01

A linear motion device, more specifically a control rod drive mechanism (CRDM) for inserting and withdrawing control rods into a reactor core, is capable of independently and sequentially positioning two sets of control rods with a single motor stator and rotor. The CRDM disclosed can control more than one control rod lead screw without incurring a substantial increase in the size of the mechanism.

Apparatus for providing a servo drive signal in a high-speed stepping interferometer

NASA Technical Reports Server (NTRS)

Schindler, R. A. (Inventor)

1979-01-01

An analog voltage approximately linearly proportional to a desired offset from the present null position of a moving mirror in an interferometer is applied to the mirror moving means. As the mirror moves to the next null position, as determined by the analog voltage, the fringes of a laser reference interference pattern are detected. At the occurrence of each fringe the analog voltage is reduced proportionally so that when the next null position is reached, this driving analog is effectively zero. A binary up/down counter, by its internal count, causes a digital/analog converter to supply the analog voltage to the mirror moving means. Fringe detection and direction of movement logic cause the binary up/down counter to be decremented from its offset count as the mirror is moved to the new null position. Undesirable movement of the mirror due to vibration or other sources causes a correcting drive signal to be applied to the mirror moving means that is proportional to the distance of movement.

Contact position sensor using constant contact force control system

NASA Technical Reports Server (NTRS)

Sturdevant, Jay (Inventor)

1995-01-01

A force control system (50) and method are provided for controlling a position contact sensor (10) so as to produce a constant controlled contact force therewith. The system (50) includes a contact position sensor (10) which has a contact probe (12) for contacting the surface of a target to be measured and an output signal (V.sub.o) for providing a position indication thereof. An actuator (30) is provided for controllably driving the contact position sensor (10) in response to an actuation control signal (I). A controller (52) receives the position indication signal (V.sub.o) and generates in response thereto the actuation control signal (I) so as to provide a substantially constant selective force (F) exerted by the contact probe (12). The actuation drive signal (I) is generated further in response to substantially linear approximation curves based on predetermined force and position data attained from the sensor (10) and the actuator (30).

Advances in shutter drive technology to enhance man-portable infrared cameras

NASA Astrophysics Data System (ADS)

Durfee, David

2012-06-01

With an emphasis on highest reliability, infrared (IR) imagers have traditionally used simplest-possible shutters and field-proven technology. Most commonly, single-step rotary or linear magnetic actuators have been used with good success. However, several newer shutter drive technologies offer benefits in size and power reduction, enabling man-portable imagers that are more compact, lighter, and more durable. This paper will discuss improvements in shutter and shutter drive technology, which enable smaller and more power-efficient imagers. Topics will transition from single-step magnetic actuators to multi-stepping magnetic drives, latching vs. balanced systems for blade position shock-resistance, motor and geared motor drives, and associated stepper driver electronics. It will highlight performance tradeoffs pertinent to man-portable military systems.

A linear chromatic mechanism drives the pupillary response.

PubMed Central

Tsujimura, S.; Wolffsohn, J. S.; Gilmartin, B.

2001-01-01

Previous studies have shown that a chromatic mechanism can drive pupil responses. The aim of this research was to clarify whether a linear or nonlinear chromatic mechanism drives pupillary responses by using test stimuli of various colours that are defined in cone contrast space. The pupil and accommodation responses evoked by these test stimuli were continuously and simultaneously objectively measured by photorefraction. The results with isochromatic and isoluminant stimuli showed that the accommodative level remained approximately constant (< 0.25 D change in mean level) even when the concurrent pupillary response was large (ca. 0.30 mm). The pupillary response to an isoluminant grating was sustained, delayed (by ca. 60 ms) and larger in amplitude than that for a isochromatic uniform stimulus, which supports previous work suggesting that the chromatic mechanism contributes to the pupillary response. In a second experiment, selected chromatic test gratings were used and isoresponse contours in cone contrast space were obtained. The results showed that the isoresponse contour in cone contrast space is well described (r(2) = 0.99) by a straight line with a positive slope. The results indicate that a /L - M/ linear chromatic mechanism, whereby a signal from the long wavelength cone is subtracted from that of the middle wavelength cone and vice versa, drives pupillary responses. PMID:11674867

Focus drive mechanism for the IUE scientific instrument

NASA Technical Reports Server (NTRS)

Devine, E. J.; Dennis, T. B., Jr.

1977-01-01

A compact, lightweight mechanism was developed for in-orbit adjustment of the position of the secondary mirror (focusing) of the International Ultraviolet Explorer telescope. This device is a linear drive with small and highly repeatable step increments. Extremely close tolerances are also held in tilt and decentering. The unique mechanization is described with attention to the design details that contribute to positional accuracy. Lubrication, materials, thermal considerations, sealing, detenting against launch loads, and other features peculiar to flight hardware are discussed. The methods employed for mounting the low expansion quartz mirror with minimum distortion are also given. Results of qualification and acceptance testing, are included.

Measurement of LHCD antenna position in Aditya tokamak

NASA Astrophysics Data System (ADS)

Ambulkar, K. K.; Sharma, P. K.; Virani, C. G.; Parmar, P. R.; Thakur, A. L.; Kulkarni, S. V.

2010-02-01

To drive plasma current non-inductively in ADITYA tokamak, 120 kW pulsed Lower Hybrid Current Drive (LHCD) system at 3.7 GHz has been designed, fabricated and installed on ADITYA tokamak. In this system, the antenna consists of a grill structure, having two rows, each row comprising of four sub-waveguides. The coupling of LHCD power to the plasma strongly depends on the plasma density near the mouth of grill antenna. Thus the grill antenna has to be precisely positioned for efficient coupling. The movement of mechanical bellow, which contracts or expands up to 50mm, governs the movement of antenna. In order to monitor the position of the antenna precisely, the reference position of the antenna with respect to the machine/plasma position has to be accurately determined. Further a mechanical system or an electronic system to measure the relative movement of the antenna with respect to the reference position is also desired. Also due to poor accessibility inside the ADITYA machine, it is impossible to measure physically the reference position of the grill antenna with respect to machine wall, taken as reference position and hence an alternative method has to be adopted to establish these measurements reliably. In this paper we report the design and development of a mechanism, using which the antenna position measurements are made. It also describes a unique method employing which the measurements of the reference position of the antenna with respect to the inner edge of the tokamak wall is carried out, which otherwise was impossible due to poor accessibility and physical constraints. The position of the antenna is monitored using an electronic scale, which is developed and installed on the bellow. Once the reference position is derived, the linear potentiometer, attached to the bellow, measures the linear distance using position transmitter. The accuracy of measurement obtained in our setup is within +/- 0.5 % and the linearity, along with repeatability is excellent.

Microfabricated microengine for use as a mechanical drive and power source in the microdomain and fabrication process

DOEpatents

Garcia, Ernest J.; Sniegowski, Jeffry J.

1997-01-01

A microengine uses two synchronized linear actuators as a power source and converts oscillatory motion from the actuators into rotational motion via direct linkage connection to an output gear or wheel. The microengine provides output in the form of a continuously rotating output gear that is capable of delivering drive torque to a micromechanism. The microengine can be operated at varying speeds and its motion can be reversed. Linear actuators are synchronized in order to provide linear oscillatory motion to the linkage means in the X and Y directions according to a desired position, rotational direction and speed of said mechanical output means. The output gear has gear teeth on its outer perimeter for directly contacting a micromechanism requiring mechanical power. The gear is retained by a retaining means which allows said gear to rotate freely. The microengine is microfabricated of polysilicon on one wafer using surface micromachining batch fabrication.

Drive control and position measurement of RailCab vehicles driven by linear motors

NASA Astrophysics Data System (ADS)

Pottharst, Andreas; Henke, Christian; Schneider, Tobias; Böcker, Joachim; Grotstollen, Horst

2006-11-01

The novel railway system RailCab makes use of autonomous vehicles which are driven by an AC linear motor. Depending on the track-side motor part, long-stator or short-stator operations are possible. The paper deals with the operation of the doubly-fed induction motor which is used for motion control and for transferring the energy required onboard the vehicle. This type of linear motor synchronization of the traveling fields generated by the stationary primary and moving secondary windings is an important and demanding task because the instantaneous positions of the vehicle or the primary traveling wave must be determined with high accuracy. The paper shows how this task is solved at the moment and what improvements are under development.

Kalman filter-based tracking of moving objects using linear ultrasonic sensor array for road vehicles

NASA Astrophysics Data System (ADS)

Li, Shengbo Eben; Li, Guofa; Yu, Jiaying; Liu, Chang; Cheng, Bo; Wang, Jianqiang; Li, Keqiang

2018-01-01

Detection and tracking of objects in the side-near-field has attracted much attention for the development of advanced driver assistance systems. This paper presents a cost-effective approach to track moving objects around vehicles using linearly arrayed ultrasonic sensors. To understand the detection characteristics of a single sensor, an empirical detection model was developed considering the shapes and surface materials of various detected objects. Eight sensors were arrayed linearly to expand the detection range for further application in traffic environment recognition. Two types of tracking algorithms, including an Extended Kalman filter (EKF) and an Unscented Kalman filter (UKF), for the sensor array were designed for dynamic object tracking. The ultrasonic sensor array was designed to have two types of fire sequences: mutual firing or serial firing. The effectiveness of the designed algorithms were verified in two typical driving scenarios: passing intersections with traffic sign poles or street lights, and overtaking another vehicle. Experimental results showed that both EKF and UKF had more precise tracking position and smaller RMSE (root mean square error) than a traditional triangular positioning method. The effectiveness also encourages the application of cost-effective ultrasonic sensors in the near-field environment perception in autonomous driving systems.

Linear motion device and method for inserting and withdrawing control rods

DOEpatents

Smith, J.E.

Disclosed is a linear motion device and more specifically a control rod drive mechanism (CRDM) for inserting and withdrawing control rods into a reactor core. The CRDM and method disclosed is capable of independently and sequentially positioning two sets of control rods with a single motor stator and rotor. The CRDM disclosed can control more than one control rod lead screw without incurring a substantial increase in the size of the mechanism.

Predicting psychopharmacological drug effects on actual driving performance (SDLP) from psychometric tests measuring driving-related skills.

PubMed

Verster, Joris C; Roth, Thomas

2012-03-01

There are various methods to examine driving ability. Comparisons between these methods and their relationship with actual on-road driving is often not determined. The objective of this study was to determine whether laboratory tests measuring driving-related skills could adequately predict on-the-road driving performance during normal traffic. Ninety-six healthy volunteers performed a standardized on-the-road driving test. Subjects were instructed to drive with a constant speed and steady lateral position within the right traffic lane. Standard deviation of lateral position (SDLP), i.e., the weaving of the car, was determined. The subjects also performed a psychometric test battery including the DSST, Sternberg memory scanning test, a tracking test, and a divided attention test. Difference scores from placebo for parameters of the psychometric tests and SDLP were computed and correlated with each other. A stepwise linear regression analysis determined the predictive validity of the laboratory test battery to SDLP. Stepwise regression analyses revealed that the combination of five parameters, hard tracking, tracking and reaction time of the divided attention test, and reaction time and percentage of errors of the Sternberg memory scanning test, together had a predictive validity of 33.4%. The psychometric tests in this test battery showed insufficient predictive validity to replace the on-the-road driving test during normal traffic.

Grasp Assist Device with Shared Tendon Actuator Assembly

NASA Technical Reports Server (NTRS)

Ihrke, Chris A. (Inventor); Bergelin, Bryan J. (Inventor); Bridgwater, Lyndon (Inventor)

2015-01-01

A grasp assist device includes a glove with first and second tendon-driven fingers, a tendon, and a sleeve with a shared tendon actuator assembly. Tendon ends are connected to the respective first and second fingers. The actuator assembly includes a drive assembly having a drive axis and a tendon hook. The tendon hook, which defines an arcuate surface slot, is linearly translatable along the drive axis via the drive assembly, e.g., a servo motor thereof. The flexible tendon is routed through the surface slot such that the surface slot divides the flexible tendon into two portions each terminating in a respective one of the first and second ends. The drive assembly may include a ball screw and nut. An end cap of the actuator assembly may define two channels through which the respective tendon portions pass. The servo motor may be positioned off-axis with respect to the drive axis.

Improved Speed Control System for the 87,000 HP Wind Tunnel Drive

NASA Technical Reports Server (NTRS)

Becks, Edward A.; Bencic, Timothy J.; Blumenthal, Philip Z.

1995-01-01

This paper describes the design, installation, and integrated systems tests for a new drive motor speed control system which was part of a recent rehab project for the NASA Lewis 8x6 Supersonic Wind Tunnel. The tunnel drive consists of three mechanically-coupled 29,000 HP wound rotor induction motors driving an axial flow compressor. Liquid rheostats are used to vary the impedance of the rotor circuits, thus varying the speed of the drive system. The new design utilizes a distributed digital control system with a dual touch screen CRT operator console to provide alarm monitoring, logging, and trending. The liquid rheostats are driven by brushtype servomotor systems with magnetostrictive linear displacement transducers used for position feedback. The new system achieved all goals for speed variations with load, motor load balance, and control of total power.

Improved speed control system for the 87,000 HP wind tunnel drive

NASA Astrophysics Data System (ADS)

Becks, Edward A.; Bencic, Timothy J.; Blumenthal, Philip Z.

1995-01-01

This paper describes the design, installation, and integrated systems tests for a new drive motor speed control system which was part of a recent rehab project for the NASA Lewis 8x6 Supersonic Wind Tunnel. The tunnel drive consists of three mechanically-coupled 29,000 HP wound rotor induction motors driving an axial flow compressor. Liquid rheostats are used to vary the impedance of the rotor circuits, thus varying the speed of the drive system. The new design utilizes a distributed digital control system with a dual touch screen CRT operator console to provide alarm monitoring, logging, and trending. The liquid rheostats are driven by brushtype servomotor systems with magnetostrictive linear displacement transducers used for position feedback. The new system achieved all goals for speed variations with load, motor load balance, and control of total power.

Negative viscosity from negative compressibility and axial flow shear stiffness in a straight magnetic field

DOE PAGES

Li, J. C.; Diamond, P. H.

2017-03-23

Here, negative compressibility ITG turbulence in a linear plasma device (CSDX) can induce a negative viscosity increment. However, even with this negative increment, we show that the total axial viscosity remains positive definite, i.e. no intrinsic axial flow can be generated by pure ITG turbulence in a straight magnetic field. This differs from the case of electron drift wave (EDW) turbulence, where the total viscosity can turn negative, at least transiently. When the flow gradient is steepened by any drive mechanism, so that the parallel shear flow instability (PSFI) exceeds the ITG drive, the flow profile saturates at a level close to the value above which PSFI becomes dominant. This saturated flow gradient exceeds the PSFI linear threshold, and grows withmore » $$\

Neighborhood environment and physical activity among older adults: do the relationships differ by driving status?

PubMed

Ding, Ding; Sallis, James F; Norman, Gregory J; Frank, Lawrence D; Saelens, Brian E; Kerr, Jacqueline; Conway, Terry L; Cain, Kelli; Hovell, Melbourne F; Hofstetter, C Richard; King, Abby C

2014-07-01

Some attributes of neighborhood environments are associated with physical activity among older adults. This study examined whether the associations were moderated by driving status. Older adults from neighborhoods differing in walkability and income completed written surveys and wore accelerometers (N = 880, mean age = 75 years, 56% women). Neighborhood environments were measured by geographic information systems and validated questionnaires. Driving status was defined on the basis of a driver's license, car ownership, and feeling comfortable to drive. Outcome variables included accelerometer-based physical activity and self-reported transport and leisure walking. Multilevel generalized linear regression was used. There was no significant Neighborhood Attribute × Driving Status interaction with objective physical activity or reported transport walking. For leisure walking, almost all environmental attributes were positive and significant among driving older adults but not among nondriving older adults (five significant interactions at p < .05). The findings suggest that driving status is likely to moderate the association between neighborhood environments and older adults' leisure walking.

Drunk driving detection based on classification of multivariate time series.

PubMed

Li, Zhenlong; Jin, Xue; Zhao, Xiaohua

2015-09-01

This paper addresses the problem of detecting drunk driving based on classification of multivariate time series. First, driving performance measures were collected from a test in a driving simulator located in the Traffic Research Center, Beijing University of Technology. Lateral position and steering angle were used to detect drunk driving. Second, multivariate time series analysis was performed to extract the features. A piecewise linear representation was used to represent multivariate time series. A bottom-up algorithm was then employed to separate multivariate time series. The slope and time interval of each segment were extracted as the features for classification. Third, a support vector machine classifier was used to classify driver's state into two classes (normal or drunk) according to the extracted features. The proposed approach achieved an accuracy of 80.0%. Drunk driving detection based on the analysis of multivariate time series is feasible and effective. The approach has implications for drunk driving detection. Copyright © 2015 Elsevier Ltd and National Safety Council. All rights reserved.

Linear active disturbance rejection control of underactuated systems: the case of the Furuta pendulum.

PubMed

Ramírez-Neria, M; Sira-Ramírez, H; Garrido-Moctezuma, R; Luviano-Juárez, A

2014-07-01

An Active Disturbance Rejection Control (ADRC) scheme is proposed for a trajectory tracking problem defined on a nonfeedback linearizable Furuta Pendulum example. A desired rest to rest angular position reference trajectory is to be tracked by the horizontal arm while the unactuated vertical pendulum arm stays around its unstable vertical position without falling down during the entire maneuver and long after it concludes. A linear observer-based linear controller of the ADRC type is designed on the basis of the flat tangent linearization of the system around an arbitrary equilibrium. The advantageous combination of flatness and the ADRC method makes it possible to on-line estimate and cancels the undesirable effects of the higher order nonlinearities disregarded by the linearization. These effects are triggered by fast horizontal arm tracking maneuvers driving the pendulum substantially away from the initial equilibrium point. Convincing experimental results, including a comparative test with a sliding mode controller, are presented. © 2013 ISA. Published by ISA. All rights reserved.

Microfabricated microengine for use as a mechanical drive and power source in the microdomain and fabrication process

DOEpatents

Garcia, E.J.; Sniegowski, J.J.

1997-05-20

A microengine uses two synchronized linear actuators as a power source and converts oscillatory motion from the actuators into rotational motion via direct linkage connection to an output gear or wheel. The microengine provides output in the form of a continuously rotating output gear that is capable of delivering drive torque to a micromechanism. The microengine can be operated at varying speeds and its motion can be reversed. Linear actuators are synchronized in order to provide linear oscillatory motion to the linkage means in the X and Y directions according to a desired position, rotational direction and speed of said mechanical output means. The output gear has gear teeth on its outer perimeter for directly contacting a micromechanism requiring mechanical power. The gear is retained by a retaining means which allows said gear to rotate freely. The microengine is microfabricated of polysilicon on one wafer using surface micromachining batch fabrication. 30 figs.

Ultrasonic Linear Motor with Two Independent Vibrations

NASA Astrophysics Data System (ADS)

Muneishi, Takeshi; Tomikawa, Yoshiro

2004-09-01

We propose a new structure of an ultrasonic linear motor in order to solve the problems of high-power ultrasonic linear motors that drive the XY-stage for electron beam equipment and to expand the application fields of the motor. We pay special attention to the following three points: (1) the vibration in two directions of the ultrasonic linear motor should not influence mutually each other, (2) the vibration in two directions should be divided into the stage traveling direction and the pressing direction of the ultrasonic linear motor, and (3) the rigidity of the stage traveling direction of the ultrasonic linear motor should be increased. As a result, the supporting method of ultrasonic linear motors is simplified. The efficiency of the motor is improved and temperature rise is reduced. The stage position drift is also improved.

Intensity dependence of focused ultrasound lesion position

NASA Astrophysics Data System (ADS)

Meaney, Paul M.; Cahill, Mark D.; ter Haar, Gail R.

1998-04-01

Knowledge of the spatial distribution of intensity loss from an ultrasonic beam is critical to predicting lesion formation in focused ultrasound surgery. To date most models have used linear propagation models to predict the intensity profiles needed to compute the temporally varying temperature distributions. These can be used to compute thermal dose contours that can in turn be used to predict the extent of thermal damage. However, these simulations fail to adequately describe the abnormal lesion formation behavior observed for in vitro experiments in cases where the transducer drive levels are varied over a wide range. For these experiments, the extent of thermal damage has been observed to move significantly closer to the transducer with increasing transducer drive levels than would be predicted using linear propagation models. The simulations described herein, utilize the KZK (Khokhlov-Zabolotskaya-Kuznetsov) nonlinear propagation model with the parabolic approximation for highly focused ultrasound waves, to demonstrate that the positions of the peak intensity and the lesion do indeed move closer to the transducer. This illustrates that for accurate modeling of heating during FUS, nonlinear effects must be considered.

Magnetic particle clutch controls servo system

NASA Technical Reports Server (NTRS)

Fow, P. B.

1973-01-01

Magnetic clutches provide alternative means of driving low-power rate or positioning servo systems. They may be used over wide variety of input speed ranges and weigh comparatively little. Power drain is good with overall motor/clutch efficiency greater than 50 percent, and gain of clutch is close to linear, following hysteresis curve of core and rotor material.

Synthesizing folded band chaos.

PubMed

Corron, Ned J; Hayes, Scott T; Pethel, Shawn D; Blakely, Jonathan N

2007-04-01

A randomly driven linear filter that synthesizes Lorenz-like, reverse-time chaos is shown also to produce Rössler-like folded band wave forms when driven using a different encoding of the random source. The relationship between the topological entropy of the random source, dissipation in the linear filter, and the positive Lyapunov exponent for the reverse-time wave form is exposed. The two drive encodings are viewed as grammar restrictions on a more general encoding that produces a chaotic superset encompassing both the Lorenz butterfly and Rössler folded band paradigms of nonlinear dynamics.

Compensation based on linearized analysis for a six degree of freedom motion simulator

NASA Technical Reports Server (NTRS)

Parrish, R. V.; Dieudonne, J. E.; Martin, D. J., Jr.; Copeland, J. L.

1973-01-01

The inertial response characteristics of a synergistic, six-degree-of-freedom motion base are presented in terms of amplitude ratio and phase lag as functions of frequency data for the frequency range of interest (0 to 2 Hz) in real time, digital, flight simulators. The notch filters which smooth the digital-drive signals to continuous drive signals are presented, and appropriate compensation, based on the inertial response data, is suggested. The existence of an inverse transformation that converts actuator extensions into inertial positions makes it possible to gather the response data in the inertial axis system.

Extent and variations in mobile phone use among drivers of heavy vehicles in Denmark.

PubMed

Troglauer, Thomas; Hels, Tove; Christens, Peter Falck

2006-01-01

A substantial body of research has shown that use of mobile phones while driving can impair driving performance and increase the risk of being involved in accidents. Similarly, mobile phone use seems to be an increasing activity thus representing a relevant traffic safety issue. This paper investigates the extent and variations in mobile phone use among drivers of heavy vehicles in Denmark. The data was collected through written questionnaires and had a response rate of 58%. It was found that more than 99% of the drivers used mobile phones while driving. Despite a prohibition of hand-held mobile phone use while driving 31% of the drivers reported to do so. Analysis of the variations in usage found a positive significant relationship between driving hours and phone use. A negative linear effect was found between age and phone use. Similarly, a positive significant association was found between the number of stops and the amount of phone use. 0.5% reported that their use of mobile phones had contributed to an accident, while 6% had experienced their mobile phone use causing a dangerous situation. However, 66% reported experiencing dangerous situations because of others road users' mobile phone use. Various implications of the findings are discussed particularly in relation to the drivers with high exposure.

Control method for prosthetic devices

NASA Technical Reports Server (NTRS)

Bozeman, Richard J., Jr. (Inventor)

1995-01-01

A control system and method for prosthetic devices is provided. The control system comprises a transducer for receiving movement from a body part for generating a sensing signal associated with that movement. The sensing signal is processed by a linearizer for linearizing the sensing signal to be a linear function of the magnitude of the distance moved by the body part. The linearized sensing signal is normalized to be a function of the entire range of body part movement from the no-shrug position of the moveable body part. The normalized signal is divided into a plurality of discrete command signals. The discrete command signals are used by typical converter devices which are in operational association with the prosthetic device. The converter device uses the discrete command signals for driving the moveable portions of the prosthetic device and its sub-prosthesis. The method for controlling a prosthetic device associated with the present invention comprises the steps of receiving the movement from the body part, generating a sensing signal in association with the movement of the body part, linearizing the sensing signal to be a linear function of the magnitude of the distance moved by the body part, normalizing the linear signal to be a function of the entire range of the body part movement, dividing the normalized signal into a plurality of discrete command signals, and implementing the plurality of discrete command signals for driving the respective moveable prosthesis device and its sub-prosthesis.

Analysis of Nonlinear Dynamics in Linear Compressors Driven by Linear Motors

NASA Astrophysics Data System (ADS)

Chen, Liangyuan

2018-03-01

The analysis of dynamic characteristics of the mechatronics system is of great significance for the linear motor design and control. Steady-state nonlinear response characteristics of a linear compressor are investigated theoretically based on the linearized and nonlinear models. First, the influence factors considering the nonlinear gas force load were analyzed. Then, a simple linearized model was set up to analyze the influence on the stroke and resonance frequency. Finally, the nonlinear model was set up to analyze the effects of piston mass, spring stiffness, driving force as an example of design parameter variation. The simulating results show that the stroke can be obtained by adjusting the excitation amplitude, frequency and other adjustments, the equilibrium position can be adjusted by adjusting the DC input, and to make the more efficient operation, the operating frequency must always equal to the resonance frequency.

Magnetically Suspended Linear Pulse Motor for Semiconductor Wafer Transfer in Vacuum Chamber

NASA Technical Reports Server (NTRS)

Moriyama, Shin-Ichi; Hiraki, Naoji; Watanabe, Katsuhide; Kanemitsu, Yoichi

1996-01-01

This paper describes a magnetically suspended linear pulse motor for a semiconductor wafer transfer robot in a vacuum chamber. The motor can drive a wafer transfer arm horizontally without mechanical contact. In the construction of the magnetic suspension system, four pairs of linear magnetic bearings for the lift control are used for the guidance control as well. This approach allows us to make the whole motor compact in size and light in weight. The tested motor consists of a double-sided stator and a transfer arm with a width of 50 mm and a total length of 700 mm. The arm, like a ladder in shape, is designed as the floating element with a tooth width of 4 mm (a tooth pitch of 8 mm). The mover mass is limited to about 1.6 kg by adopting such an arm structure, and the ratio of thrust to mover mass reaches to 3.2 N/kg under a broad air gap (1 mm) between the stator teeth and the mover teeth. The performance testing was carried out with a transfer distance less than 450 mm and a transfer speed less than 560 mm/s. The attitude of the arm was well controlled by the linear magnetic bearings with a combined use, and consequently the repeatability on the positioning of the arm reached to about 2 micron. In addition, the positioning accuracy was improved up to about 30 micron through a compensation of the 128-step wave current which was used for the micro-step drive with a step increment of 62.5 micron.

Novel AC Servo Rotating and Linear Composite Driving Device for Plastic Forming Equipment

NASA Astrophysics Data System (ADS)

Liang, Jin-Tao; Zhao, Sheng-Dun; Li, Yong-Yi; Zhu, Mu-Zhi

2017-07-01

The existing plastic forming equipment are mostly driven by traditional AC motors with long transmission chains, low efficiency, large size, low precision and poor dynamic response are the common disadvantages. In order to realize high performance forming processes, the driving device should be improved, especially for complicated processing motions. Based on electric servo direct drive technology, a novel AC servo rotating and linear composite driving device is proposed, which features implementing both spindle rotation and feed motion without transmission, so that compact structure and precise control can be achieved. Flux switching topology is employed in the rotating drive component for strong robustness, and fractional slot is employed in the linear direct drive component for large force capability. Then the mechanical structure for compositing rotation and linear motion is designed. A device prototype is manufactured, machining of each component and the whole assembly are presented respectively. Commercial servo amplifiers are utilized to construct the control system of the proposed device. To validate the effectiveness of the proposed composite driving device, experimental study on the dynamic test benches are conducted. The results indicate that the output torque can attain to 420 N·m and the dynamic tracking errors are less than about 0.3 rad in the rotating drive. the dynamic tracking errors are less than about 1.6 mm in the linear feed. The proposed research provides a method to construct high efficiency and accuracy direct driving device in plastic forming equipment.

The intensity dependence of lesion position shift during focused ultrasound surgery.

PubMed

Meaney, P M; Cahill, M D; ter Haar, G R

2000-03-01

Knowledge of the spatial distribution of intensity loss from an ultrasonic beam is critical for predicting lesion formation in focused ultrasound (US) surgery (FUS). To date, most models have used linear propagation models to predict intensity profiles required to compute the temporally varying temperature distributions used to compute thermal dose contours. These are used to predict the extent of thermal damage. However, these simulations fail to describe adequately the abnormal lesion formation behaviour observed during ex vivo experiments in cases for which the transducer drive levels are varied over a wide range. In such experiments, the extent of thermal damage has been observed to move significantly closer to the transducer with increased transducer drive levels than would be predicted using linear-propagation models. The first set of simulations described herein use the KZK (Khokhlov-Zabolotskaya-Kuznetsov) nonlinear propagation model with the parabolic approximation for highly focused US waves to demonstrate that both the peak intensity and the lesion positions do, indeed, move closer to the transducer. This illustrates that, for accurate modelling of heating during FUS, nonlinear effects should be considered. Additionally, a first order approximation has been employed that attempts to account for the abnormal heat deposition distributions that accompany high transducer drive level FUS exposures where cavitation and boiling may be present. The results of these simulations are presented. It is suggested that this type of approach may be a useful tool in understanding thermal damage mechanisms.

Modeling of Passive Forces of Machine Tool Covers

NASA Astrophysics Data System (ADS)

Kolar, Petr; Hudec, Jan; Sulitka, Matej

The passive forces acting against the drive force are phenomena that influence dynamical properties and precision of linear axes equipped with feed drives. Covers are one of important sources of passive forces in machine tools. The paper describes virtual evaluation of cover passive forces using the cover complex model. The model is able to compute interaction between flexible cover segments and sealing wiper. The result is deformation of cover segments and wipers which is used together with measured friction coefficient for computation of cover total passive force. This resulting passive force is dependent on cover position. Comparison of computational results and measurement on the real cover is presented in the paper.

A double B1-mode 4-layer laminated piezoelectric linear motor.

PubMed

Li, Xiaotian; Chen, Zhijiang; Dong, Shuxiang

2012-12-01

We report a miniature piezoelectric ultrasonic linear motor that is made of four Pb(Zr,Ti)O(3) (PZT) piezoelectric ceramic layers for low-voltage work. The 4-layer piezoelectric laminate works in two orthogonal first-bending modes for producing elliptical oscillations, which are then used to drive a contacting slider into continuous linear motion. Experimental results show that the miniature linear motor (size: 4 × 4 × 12 mm, weight: 1.7 g) can generate a large driving force of 0.48 N and a linear motion speed of up to 160 mm/s, using a 40 V(pp)/mm voltage drive at its resonance frequency of 64.5 kHz. The maximum efficiency of the linear motor is 30%.

Increased parent limits on teen driving: positive effects from a brief intervention administered at the Motor Vehicle Administration.

PubMed

Simons-Morton, Bruce G; Hartos, Jessica L; Beck, Kenneth H

2004-06-01

The purpose of this study was to determine whether exposure to a brief intervention administered at the Motor Vehicle Administration (MVA) increases parental limits on teen driving. A total of 658 parents and their 16-year-old adolescents were recruited from a local MVA site as adolescents successfully tested for provisional licenses. At the MVA, participating parents completed written surveys about expected teen driving during the 1st month of provisional licensure. One month later, 579 parent-teen dyads completed follow-up telephone interviews about teen driving within the past month. On weeks assigned as intervention, parents were exposed to a video and given the video and a driving agreement to take home. In multivariate linear regression analyses, the results indicated that when controlling for selected demographic and baseline psychosocial variables, intervention parents reported more driving rules, restricted driving, limits for high-speed roads, weekend night restrictions, and overall driving limits than did parents in the control group. When compared to control teens, intervention teens reported more limits on passengers, high-speed roads, and night driving, and on overall driving limits, but there were no differences for overall driving or driving under high-risk conditions. In addition, intervention parents were about 3 times, and intervention teens were about 5 times, more likely than controls to report using a parent-teen driving agreement. These results indicate that brief exposure to intervention at an MVA office may help increase parental limits on teen driving.

Sequenced drive for rotary valves

DOEpatents

Mittell, Larry C.

1981-01-01

A sequenced drive for rotary valves which provides the benefits of applying rotary and linear motions to the movable sealing element of the valve. The sequenced drive provides a close approximation of linear motion while engaging or disengaging the movable element with the seat minimizing wear and damage due to scrubbing action. The rotary motion of the drive swings the movable element out of the flowpath thus eliminating obstruction to flow through the valve.

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

Asplund, Curtis T., E-mail: ca2621@columbia.edu; Berenstein, David, E-mail: dberens@physics.ucsb.edu

We consider oscillators evolving subject to a periodic driving force that dynamically entangles them, and argue that this gives the linearized evolution around periodic orbits in a general chaotic Hamiltonian dynamical system. We show that the entanglement entropy, after tracing over half of the oscillators, generically asymptotes to linear growth at a rate given by the sum of the positive Lyapunov exponents of the system. These exponents give a classical entropy growth rate, in the sense of Kolmogorov, Sinai and Pesin. We also calculate the dependence of this entropy on linear mixtures of the oscillator Hilbert-space factors, to investigate themore » dependence of the entanglement entropy on the choice of coarse graining. We find that for almost all choices the asymptotic growth rate is the same.« less

A Car-Steering Model Based on an Adaptive Neuro-Fuzzy Controller

NASA Astrophysics Data System (ADS)

Amor, Mohamed Anis Ben; Oda, Takeshi; Watanabe, Shigeyoshi

This paper is concerned with the development of a car-steering model for traffic simulation. Our focus in this paper is to propose a model of the steering behavior of a human driver for different driving scenarios. These scenarios are modeled in a unified framework using the idea of target position. The proposed approach deals with the driver’s approximation and decision-making mechanisms in tracking a target position by means of fuzzy set theory. The main novelty in this paper lies in the development of a learning algorithm that has the intention to imitate the driver’s self-learning from his driving experience and to mimic his maneuvers on the steering wheel, using linear networks as local approximators in the corresponding fuzzy areas. Results obtained from the simulation of an obstacle avoidance scenario show the capability of the model to carry out a human-like behavior with emphasis on learned skills.

Resonant-type Smooth Impact Drive Mechanism (SIDM) actuator using a bolt-clamped Langevin transducer.

PubMed

Nishimura, Takuma; Hosaka, Hiroshi; Morita, Takeshi

2012-01-01

The Smooth Impact Drive Mechanism (SIDM) is a linear piezoelectric actuator that has seen practically applied to camera lens modules. Although previous SIDM actuators are easily miniaturized and enable accurate positioning, these actuators cannot actuate at high speed and cannot provide powerful driving because they are driven at an off-resonant frequency using a soft-type PZT. In the present study, we propose a resonant-type SIDM using a bolt-clamped Langevin transducer (BLT) with a hard-type PZT. The resonant-type SIDM overcomes the above-mentioned problems and high-power operation becomes possible with a very simple structure. As a result, we confirmed the operation of resonant-type SIDM by designing a bolt-clamped Langevin transducer. The properties of no-load maximum speed was 0.28m/s at driving voltages of 80V(p-p) for 44.9kHz and 48V(p-p) for 22.45kHz with a pre-load of 3.1N. Copyright © 2011 Elsevier B.V. All rights reserved.

Driving Comparisons Between Young Adults with Autism Spectrum Disorder and Typical Development.

PubMed

Patrick, Kristina E; Hurewitz, Felicia; McCurdy, Mark D; Agate, Frederic Taylor; Daly, Brian P; Tarazi, Reem A; Chute, Douglas L; Schultheis, Maria T

2018-05-18

Many individuals with autism spectrum disorder (ASD) are reluctant to pursue driving because of concerns about their ability to drive safely. This study aimed to assess differences in simulated driving performance in young adults with ASD and typical development, examining relationships between driving performance and the level of experience (none, driver's permit, licensed) across increasingly difficult driving environments. Participants included 50 English-speaking young adults (16-26 years old) with ASD matched for sex, age, and licensure with 50 typically-developing (TD) peers. Participants completed a structured driving assessment using a virtual-reality simulator that included increasingly complex environmental demands. Differences in mean speed and speed and lane variability by diagnostic group and driving experience were analyzed using multilevel linear modeling. Young adults with ASD demonstrated increased variability in speed and lane positioning compared with controls, even during low demand tasks. When driving demands became more complex, group differences were moderated by driving experience such that licensed drivers with ASD drove similarly to TD licensed drivers for most tasks, whereas unlicensed drivers with ASD had more difficulty with speed and lane management than TD drivers. Findings suggest that young adults with ASD may have more difficulty with basic driving skills than peers, particularly in the early stages of driver training. Increased difficulty compared with peers increases as driving demands become more complex, suggesting that individuals with ASD may benefit from a slow and gradual approach to driver training. Future studies should evaluate predictors of driving performance, on-road driving, and ASD-specific driving interventions.

Mechatronic Aeropendulum: Demonstration of Linear and Nonlinear Feedback Control Principles with MATLAB/Simulink Real-Time Windows Target

ERIC Educational Resources Information Center

Enikov, E. T.; Campa, G.

2012-01-01

This paper presents a low-cost hands-on experiment for a classical undergraduate controls course for non-electrical engineering majors. The setup consists of a small dc electrical motor attached to one of the ends of a light rod. The motor drives a 2-in propeller and allows the rod to swing. Angular position is measured by a potentiometer attached…

Mössbauer spectra linearity improvement by sine velocity waveform followed by linearization process

NASA Astrophysics Data System (ADS)

Kohout, Pavel; Frank, Tomas; Pechousek, Jiri; Kouril, Lukas

2018-05-01

This note reports the development of a new method for linearizing the Mössbauer spectra recorded with a sine drive velocity signal. Mössbauer spectra linearity is a critical parameter to determine Mössbauer spectrometer accuracy. Measuring spectra with a sine velocity axis and consecutive linearization increases the linearity of spectra in a wider frequency range of a drive signal, as generally harmonic movement is natural for velocity transducers. The obtained data demonstrate that linearized sine spectra have lower nonlinearity and line width parameters in comparison with those measured using a traditional triangle velocity signal.

Modeling startup and shutdown transient of the microlinear piezo drive via ANSYS

NASA Astrophysics Data System (ADS)

Azin, A. V.; Bogdanov, E. P.; Rikkonen, S. V.; Ponomarev, S. V.; Khramtsov, A. M.

2017-02-01

The article describes the construction-design of the micro linear piezo drive intended for a peripheral cord tensioner in the reflecting surface shape regulator system for large-sized transformable spacecraft antenna reflectors. The research target -the development method of modeling startup and shutdown transient of the micro linear piezo drive. This method is based on application software package ANSYS. The method embraces a detailed description of the calculation stages to determine the operating characteristics of the designed piezo drive. Based on the numerical solutions, the time characteristics of the designed piezo drive are determined.

Piezoelectric step-motion actuator

DOEpatents

Mentesana,; Charles, P [Leawood, KS

2006-10-10

A step-motion actuator using piezoelectric material to launch a flight mass which, in turn, actuates a drive pawl to progressively engage and drive a toothed wheel or rod to accomplish stepped motion. Thus, the piezoelectric material converts electrical energy into kinetic energy of the mass, and the drive pawl and toothed wheel or rod convert the kinetic energy of the mass into the desired rotary or linear stepped motion. A compression frame may be secured about the piezoelectric element and adapted to pre-compress the piezoelectric material so as to reduce tensile loads thereon. A return spring may be used to return the mass to its resting position against the compression frame or piezoelectric material following launch. Alternative embodiment are possible, including an alternative first embodiment wherein two masses are launched in substantially different directions, and an alternative second embodiment wherein the mass is eliminated in favor of the piezoelectric material launching itself.

Linear mass actuator

NASA Technical Reports Server (NTRS)

Holloway, Sidney E., III (Inventor); Crossley, Edward A., Jr. (Inventor); Jones, Irby W. (Inventor); Miller, James B. (Inventor); Davis, C. Calvin (Inventor); Behun, Vaughn D. (Inventor); Goodrich, Lewis R., Sr. (Inventor)

1992-01-01

A linear mass actuator includes an upper housing and a lower housing connectable to each other and having a central passageway passing axially through a mass that is linearly movable in the central passageway. Rollers mounted in the upper and lower housings in frictional engagement with the mass translate the mass linearly in the central passageway and drive motors operatively coupled to the roller means, for rotating the rollers and driving the mass axially in the central passageway.

Base drive circuit

DOEpatents

Lange, A.C.

1995-04-04

An improved base drive circuit having a level shifter for providing bistable input signals to a pair of non-linear delays. The non-linear delays provide gate control to a corresponding pair of field effect transistors through a corresponding pair of buffer components. The non-linear delays provide delayed turn-on for each of the field effect transistors while an associated pair of transistors shunt the non-linear delays during turn-off of the associated field effect transistor. 2 figures.

A square-plate ultrasonic linear motor operating in two orthogonal first bending modes.

PubMed

Chen, Zhijiang; Li, Xiaotian; Chen, Jianguo; Dong, Shuxiang

2013-01-01

A novel square-plate piezoelectric ultrasonic linear motor operated in two orthogonal first bending vibration modes (B₁) is proposed. The piezoelectric vibrator of the linear motor is simply made of a single PZT ceramic plate (sizes: 15 x 15 x 2 mm) and poled in its thickness direction. The top surface electrode of the square ceramic plate was divided into four active areas along its two diagonal lines for exciting two orthogonal B₁ modes. The achieved driving force and speed from the linear motor are 1.8 N and 230 mm/s, respectively, under one pair orthogonal voltage drive of 150 V(p-p) at the resonance frequency of 92 kHz. The proposed linear motor has advantages over conventional ultrasonic linear motors, such as relatively larger driving force, very simple working mode and structure, and low fabrication cost.

Trapping and Injecting Single Domain Walls in Magnetic Wire by Local Fields

NASA Astrophysics Data System (ADS)

Vázquez, Manuel; Basheed, G. A.; Infante, Germán; Del Real, Rafael P.

2012-01-01

A single domain wall (DW) moves at linearly increasing velocity under an increasing homogeneous drive magnetic field. Present experiments show that the DW is braked and finally trapped at a given position when an additional antiparallel local magnetic field is applied. That position and its velocity are further controlled by suitable tuning of the local field. In turn, the parallel local field of small amplitude does not significantly affect the effective wall speed at long distance, although it generates tail-to-tail and head-to-head pairs of walls moving along opposite directions when that field is strong enough.

Electromagnetic miniactuators using thin magnetic layers

NASA Astrophysics Data System (ADS)

Kube, H.; Zoeppig, V.; Hermann, R.; Hoffmann, A.; Kallenbach, E.

2000-06-01

This paper presents two examples of miniactuators based on the electromagnetic and electrodynamic force generation principle respectively. They use modern high-energy polymer-bonded permanent magnetic layers basing on NdFeB. The first example is a linear drive with an integrated magnetic bearing. It generates electrodynamic forces to lift and move a lightweight platen. The position of the platen is measured and controlled. The second example is a miniature pneumatic valve with a fully integrated polarized electromagnetic actuator. The valve consumes power only when the armature position is changed. The holding force is generated without consumption of power.

13th International Conference on Magnetically Levitated Systems and Linear Drives

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

Not Available

1993-09-01

This report contains short papers on research being conducted throughout the world on magnetically levitated systems, mainly consisting of trains, and magnetic linear drives. These papers have been index separately elsewhere on the data base.

Tool setting device

DOEpatents

Brown, Raymond J.

1977-01-01

The present invention relates to a tool setting device for use with numerically controlled machine tools, such as lathes and milling machines. A reference position of the machine tool relative to the workpiece along both the X and Y axes is utilized by the control circuit for driving the tool through its program. This reference position is determined for both axes by displacing a single linear variable displacement transducer (LVDT) with the machine tool through a T-shaped pivotal bar. The use of the T-shaped bar allows the cutting tool to be moved sequentially in the X or Y direction for indicating the actual position of the machine tool relative to the predetermined desired position in the numerical control circuit by using a single LVDT.

On the approximation of Lyapunov exponents and a question suggested by Anatole Katok

NASA Astrophysics Data System (ADS)

Dai, Xiongping

2010-03-01

Let \\mathcal {F}\\colon X\\times\\mathbb{Z}_+\\rightarrow \\rm{GL}(n,\\mathbb{R}) be a Hölder-continuous linear cocycle whose driving semiflow f\\colon X\\times\\mathbb{Z}_+\\rightarrow X preserves a probability μ on a compact metric space X. Using the concept of two-sided quasi-Pesin orbits introduced in this paper, we show that the Lyapunov characteristic spectrum of μ can be approached arbitrarily by that of periodic points of f. So, if all periodic points of f have only positive Lyapunov exponents and such exponents are uniformly bounded away from zero, then μ also has only positive exponents. In our arguments, the exponential closing property of the driving semiflow is a basic condition, and it is easy to check that every C1-expanding map of a closed manifold obeys this closing property. Consequently, if f is a C1+Hölder local diffeomorphism of a closed manifold and if it is Hölder conjugated to some C1-expanding map, then f is itself expanding. This gives a positive answer to a question suggested by Anatole Katok.

Split-Stirling-cycle displacer linear-electric drive

NASA Technical Reports Server (NTRS)

Ackermann, R. A.; Bhate, S. K.; Byrne, D. V.

1983-01-01

The retrofit of a 1/4-W split-Stirling cooler with a linear driven on the displacer was achieved and its performance characterized. The objective of this work was to demonstrate that a small linear motor could be designed to meet the existing envelope specifications of the cooler and that an electric linear drive on the displacer could improve the cooler's reliability and performance. The paper describes the characteristics of this motor and presents cooler test results.

Friction drive position transducer

NASA Astrophysics Data System (ADS)

Waclawik, Ronald E.; Cayer, James L.; Lapointe, Kenneth M.

1991-10-01

A spring force loaded contact wheel mounted in a stationary position relative to a reciprocating shaft is disclosed. The apparatus of the present invention includes a tensioning assembly for maintaining absolute contact between the contact wheel and the reciprocating shaft wherein the tensioning assembly urges the contact wheel against the shaft to maintain contact therebetween so that the wheel turns as the shaft is linearly displaced. A rotary encoding device is coupled to the wheel for translating the angular and rotational movement thereof into an electronic signal for providing linear displacement information and derivative data with respect to displacement of the shaft. Absolute friction contact and cooperative interaction between the shaft and the contact wheel is further enhanced in the preferred embodiment by advantageously selecting the types of surface finish and the amount of surface area of the contact wheel relative to the surface condition of the shaft as well as by reducing the moment of inertia of the contact wheel.

Friction drive position transducer

NASA Astrophysics Data System (ADS)

Waclawik, Ronald E.; Cayer, James L.; Lapointe, Kenneth M.

1993-06-01

A spring force loaded contact wheel mounted in a stationary position relative to a reciprocating shaft is disclosed. The apparatus of the present invention includes a tensioning assembly for maintaining absolute contact between the contact wheel and the reciprocating shaft wherein the tensioning assembly urges the contact wheel against the shaft to maintain contact there between so that the wheel turn as the shaft is linearly displaced. A rotary encoding device is coupled to the wheel for translating the angular and rotational movement thereof into an electronic signal for providing linear displacement information and derivative data with respect to displacement of the shaft. Absolute friction contact and cooperative interaction between the shaft and the contact wheel is further enhanced in the preferred embodiment by advantageously selecting the type of surface finish and the amount of surface area of the contact wheel relative to the surface condition of the shaft as well as by reducing the moment of inertia of the contact wheel.

COAXIAL CONTROL ROD DRIVE MECHANISM FOR NEUTRONIC REACTORS

DOEpatents

Fox, R.J.; Oakes, L.C.

1959-04-14

A drive mechanism is presented for the control rod or a nuclear reactor. In this device the control rod is coupled to a drive shaft which extends coaxially through the rotor of an electric motor for relative rotation with respect thereto. A gear reduction mehanism is coupled between the rotor and the drive shaft to convert the rotary motion of the motor into linear motion of the shaft with a comparatively great reduction in speed, thereby providing relatively glow linear movement of the shaft and control rod for control purposes.

High-precision control of LSRM based X-Y table for industrial applications.

PubMed

Pan, J F; Cheung, Norbert C; Zou, Yu

2013-01-01

The design of an X-Y table applying direct-drive linear switched reluctance motor (LSRM) principle is proposed in this paper. The proposed X-Y table has the characteristics of low cost, simple and stable mechanical structure. After the design procedure is introduced, an adaptive position control method based on online parameter identification and pole-placement regulation scheme is developed for the X-Y table. Experimental results prove the feasibility and its priority over a traditional PID controller with better dynamic response, static performance and robustness to disturbances. It is expected that the novel two-dimensional direct-drive system find its applications in high-precision manufacture area. Copyright © 2012 ISA. Published by Elsevier Ltd. All rights reserved.

A simulation study of the effects of alcohol on driving performance in a Chinese population.

PubMed

Li, Y C; Sze, N N; Wong, S C; Yan, Wei; Tsui, K L; So, F L

2016-10-01

Driving under the influence of alcohol (DUIA) is a significant factor contributing to road traffic crashes, injuries, and fatalities. Although the effects of alcohol on driving performance are widely acknowledged, studies of the effects of alcohol impairment on driving performance and particularly on the control system of Chinese adults are rare. This study attempts to evaluate the effects of alcohol on the driving performance of Chinese adults using a driving simulator. A double-blind experimental study was conducted to evaluate the effects of alcohol impairment on the driving performance of 52 Chinese participants using a driving simulator. A series of simulated driving tests covering two driving modules, including emergency braking (EB) and following braking (FB), at 50km/h and 80km/h were performed. Linear mixed models were established to evaluate driving performance in terms of braking reaction time (BRT), the standard deviation of lateral position (SD-LANE), and the standard deviation of speed (SD-SPEED). Driving performance in terms of BRT and SD-LANE was highly correlated with the level of alcohol consumption, with a one-unit increase in breath alcohol concentration (BrAC) degrading BRT and SD-LANE by 0.3% and 0.2%, respectively. Frequent drinkers generally reacted faster in their BRT than less-frequent drinkers and non-drinkers by 10.2% and 30.6%, respectively. Moreover, alcohol impairment had varying effects on certain aspects of the human control system, and automatic action was less likely to be affected than voluntary action from a psychological viewpoint. The findings should be useful for planning and developing effective measures to combat drink driving in Chinese communities. Copyright © 2016 Elsevier Ltd. All rights reserved.

Robot Arm with Tendon Connector Plate and Linear Actuator

NASA Technical Reports Server (NTRS)

Bridgwater, Lyndon (Inventor); Millerman, Alexander (Inventor); Ihrke, Chris A. (Inventor); Diftler, Myron A. (Inventor); Nguyen, Vienny (Inventor)

2014-01-01

A robotic system includes a tendon-driven end effector, a linear actuator, a flexible tendon, and a plate assembly. The linear actuator assembly has a servo motor and a drive mechanism, the latter of which translates linearly with respect to a drive axis of the servo motor in response to output torque from the servo motor. The tendon connects to the end effector and drive mechanism. The plate assembly is disposed between the linear actuator assembly and the tendon-driven end effector and includes first and second plates. The first plate has a first side that defines a boss with a center opening. The second plate defines an accurate through-slot having tendon guide channels. The first plate defines a through passage for the tendon between the center opening and a second side of the first plate. A looped end of the flexible tendon is received within the tendon guide channels.

A linear magnetic motor and generator

NASA Technical Reports Server (NTRS)

Studer, P. A.

1980-01-01

In linear magnetic motor and generator suitable for remote and hostile environments, magnetic forces drive reciprocating shaft along its axis. Actuator shaft is located in center of cylindrical body and may be supported by either contacting or noncontacting bearings. When device operates as bidirectional motor, drive coil selectively adds and subtracts magnetic flux to and from flux paths, producing forces that drive actuator along axis. When actuator is driven by external reciprocating engine, device becomes ac generator.

Differences in 1D electron plasma wake field acceleration in MeV versus GeV and linear versus blowout regimes

NASA Astrophysics Data System (ADS)

Tsiklauri, David

2018-03-01

In some laboratory and most astrophysical situations, plasma wake-field acceleration of electrons is one dimensional, i.e., variation transverse to the beam's motion can be ignored. Thus, one dimensional, particle-in-cell (PIC), fully electromagnetic simulations of electron plasma wake field acceleration are conducted in order to study the differences in electron plasma wake field acceleration in MeV versus GeV and linear versus blowout regimes. First, we show that caution needs to be taken when using fluid simulations, as PIC simulations prove that an approximation for an electron bunch not to evolve in time for a few hundred plasma periods only applies when it is sufficiently relativistic. This conclusion is true irrespective of the plasma temperature. We find that in the linear regime and GeV energies, the accelerating electric field generated by the plasma wake is similar to the linear and MeV regimes. However, because GeV energy driving bunch stays intact for a much longer time, the final acceleration energies are much larger in the GeV energies case. In the GeV energy range and blowout regime, the wake's accelerating electric field is much larger in amplitude compared with the linear case and also plasma wake geometrical size is much larger. Thus, the correct positioning of the trailing bunch is needed to achieve the efficient acceleration. For the considered case, optimally, there should be approximately (90-100)c/ωpe distance between the trailing and driving electron bunches in the GeV blowout regime.

ADVANCED DESIGNS OF MAGNETIC JACK-TYPE CONTROL ROD DRIVE

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

Young, J.N.

1959-11-01

The magnetic jack is a device for positioning the control rods In a nuclear reactor, especially in a reactor containing water under pressure. Magnetic actuation precludes the need for shaft seals and eliminates the problems associated with mechanisms operating in water. It consists of a pressure shell, four sets of external stationary magnet coils (hold, grip, lift, pull down), and one Internal moving part (ammature) that impants linear motion to a cluster of rods. (W.L.H.)

To Be or Not To Be...Perceived Benefits of Mentoring In the United States Air Force

DTIC Science & Technology

2013-06-01

negative , and this perception of the process can drive individuals from future relationships. For this reason, career-influencing factors have to be...to discuss the positive and negative perceptions of mentoring on twenty-first century Airman. In this study, the focus is on mentoring and non...different stages of life. Each compartment segments linear periods in a given lifespan. From the middle of childhood to that of adolescence

Analysis, design, and testing of a low cost, direct force command linear proof mass actuator for structural control

NASA Technical Reports Server (NTRS)

Slater, G. L.; Shelley, Stuart; Jacobson, Mark

1993-01-01

In this paper, the design, analysis, and test of a low cost, linear proof mass actuator for vibration control is presented. The actuator is based on a linear induction coil from a large computer disk drive. Such disk drives are readily available and provide the linear actuator, current feedback amplifier, and power supply for a highly effective, yet inexpensive, experimental laboratory actuator. The device is implemented as a force command input system, and the performance is virtually the same as other, more sophisticated, linear proof mass systems.

Report on the status of linear drive coolers for the Department of Defense Standard Advanced Dewar Assembly (SADA)

NASA Astrophysics Data System (ADS)

Salazar, William

2003-01-01

The Standard Advanced Dewar Assembly (SADA) is the critical module in the Department of Defense (DoD) standardization effort of scanning second-generation thermal imaging systems. DoD has established a family of SADA's to address requirements for high performance (SADA I), mid-to-high performance (SADA II), and compact class (SADA III) systems. SADA's consist of the Infrared Focal Plane Array (IRFPA), Dewar, Command and Control Electronics (C&CE), and the cryogenic cooler. SADA's are used in weapons systems such as Comanche and Apache helicopters, the M1 Abrams Tank, the M2 Bradley Fighting Vehicle, the Line of Sight Antitank (LOSAT) system, the Improved Target Acquisition System (ITAS), and Javelin's Command Launch Unit (CLU). DOD has defined a family of tactical linear drive coolers in support of the family of SADA's. The Stirling linear drive cryo-coolers are utilized to cool the SADA's Infrared Focal Plane Arrays (IRFPAs) to their operating cryogenic temperatures. These linear drive coolers are required to meet strict cool-down time requirements along with lower vibration output, lower audible noise, and higher reliability than currently fielded rotary coolers. This paper will (1) outline the characteristics of each cooler, (2) present the status and results of qualification tests, and (3) present the status and test results of efforts to increase linear drive cooler reliability.

Trends in non-stationary signal processing techniques applied to vibration analysis of wind turbine drive train - A contemporary survey

NASA Astrophysics Data System (ADS)

Uma Maheswari, R.; Umamaheswari, R.

2017-02-01

Condition Monitoring System (CMS) substantiates potential economic benefits and enables prognostic maintenance in wind turbine-generator failure prevention. Vibration Monitoring and Analysis is a powerful tool in drive train CMS, which enables the early detection of impending failure/damage. In variable speed drives such as wind turbine-generator drive trains, the vibration signal acquired is of non-stationary and non-linear. The traditional stationary signal processing techniques are inefficient to diagnose the machine faults in time varying conditions. The current research trend in CMS for drive-train focuses on developing/improving non-linear, non-stationary feature extraction and fault classification algorithms to improve fault detection/prediction sensitivity and selectivity and thereby reducing the misdetection and false alarm rates. In literature, review of stationary signal processing algorithms employed in vibration analysis is done at great extent. In this paper, an attempt is made to review the recent research advances in non-linear non-stationary signal processing algorithms particularly suited for variable speed wind turbines.

Development of portable health monitoring system for automatic self-blood glucose measurement

NASA Astrophysics Data System (ADS)

Kim, Huijun; Mizuno, Yoshihumi; Nakamachi, Eiji; Morita, Yusuke

2010-02-01

In this study, a new HMS (Health Monitoring System) device is developed for diabetic patient. This device mainly consists of I) 3D blood vessel searching unit and II) automatic blood glucose measurement (ABGM) unit. This device has features such as 1)3D blood vessel location search 2) laptop type, 3) puncturing a blood vessel by using a minimally invasive micro-needle, 4) very little blood sampling (10μl), and 5) automatic blood extraction and blood glucose measurement. In this study, ABGM unit is described in detail. It employs a syringe type's blood extraction mechanism because of its high accuracy. And it consists of the syringe component and the driving component. The syringe component consists of a syringe itself, a piston, a magnet, a ratchet and a micro-needle whose inner diameter is about 80μm. And the syringe component is disposable. The driving component consists of body parts, a linear stepping motor, a glucose enzyme sensor and a slider for accurate positioning control. The driving component has the all-in-one mechanism with a glucose enzyme sensor for compact size and stable blood transfer. On designing, required thrust force to drive the slider is designed to be greater than the value of the blood extraction force. Further, only one linear stepping motor is employed for blood extraction and transportation processes. The experimental result showed more than 80% of volume ratio under the piston speed 2.4mm/s. Further, the blood glucose was measured successfully by using the prototype unit. Finally, the availability of our ABGM unit was confirmed.

Design of a Pneumatic Tool for Manual Drilling Operations in Confined Spaces

NASA Astrophysics Data System (ADS)

Janicki, Benjamin

This master's thesis describes the design process and testing results for a pneumatically actuated, manually-operated tool for confined space drilling operations. The purpose of this device is to back-drill pilot holes inside a commercial airplane wing. It is lightweight, and a "locator pin" enables the operator to align the drill over a pilot hole. A suction pad stabilizes the system, and an air motor and flexible drive shaft power the drill. Two testing procedures were performed to determine the practicality of this prototype. The first was the "offset drill test", which qualified the exit hole position error due to an initial position error relative to the original pilot hole. The results displayed a linear relationship, and it was determined that position errors of less than .060" would prevent the need for rework, with errors of up to .030" considered acceptable. For the second test, a series of holes were drilled with the pneumatic tool and analyzed for position error, diameter range, and cycle time. The position errors and hole diameter range were within the allowed tolerances. The average cycle time was 45 seconds, 73 percent of which was for drilling the hole, and 27 percent of which was for positioning the device. Recommended improvements are discussed in the conclusion, and include a more durable flexible drive shaft, a damper for drill feed control, and a more stable locator pin.

Base drive circuit

DOEpatents

Lange, Arnold C.

1995-01-01

An improved base drive circuit (10) having a level shifter (24) for providing bistable input signals to a pair of non-linear delays (30, 32). The non-linear delays (30, 32) provide gate control to a corresponding pair of field effect transistors (100, 106) through a corresponding pair of buffer components (88, 94). The non-linear delays (30, 32) provide delayed turn-on for each of the field effect transistors (100, 106) while an associated pair of transistors (72, 80) shunt the non-linear delays (30, 32) during turn-off of the associated field effect transistor (100, 106).

A square-plate piezoelectric linear motor operating in two orthogonal and isomorphic face-diagonal-bending modes.

PubMed

Ci, Penghong; Chen, Zhijiang; Liu, Guoxi; Dong, Shuxiang

2014-01-01

We report a piezoelectric linear motor made of a single Pb(Zr,Ti)O3 square-plate, which operates in two orthogonal and isomorphic face-diagonal-bending modes to produce precision linear motion. A 15 × 15 × 2 mm prototype was fabricated, and the motor generated a driving force of up to 1.8 N and a speed of 170 mm/s under an applied voltage of 100 Vpp at the resonance frequency of 136.5 kHz. The motor shows such advantages as large driving force under relatively low driving voltage, simple structure, and stable motion because of its isomorphic face-diagonal-bending mode.

Optical-Path-Difference Linear Mechanism for the Panchromatic Fourier Transform Spectrometer

NASA Technical Reports Server (NTRS)

Blavier, Jean-Francois L.; Heverly, Matthew C.; Key, Richard W.; Sander, Stanley P.

2011-01-01

A document discusses a mechanism that uses flex-pivots in a parallelogram arrangement to provide frictionless motion with an unlimited lifetime. A voicecoil actuator drives the parallelogram over the required 5-cm travel. An optical position sensor provides feedback for a servo loop that keeps the velocity within 1 percent of expected value. Residual tip/tilt error is compensated for by a piezo actuator that drives the interferometer mirror. This mechanism builds on previous work that targeted ground-based measurements. The main novelty aspects include cryogenic and vacuum operation, high reliability for spaceflight, compactness of the design, optical layout compatible with the needs of an imaging FTS (i.e. wide overall field-of-view), and mirror optical coatings to cover very broad wavelength range (i.e., 0.26 to 15 m).

High reliability linear drive device for artificial hearts

NASA Astrophysics Data System (ADS)

Ji, Jinghua; Zhao, Wenxiang; Liu, Guohai; Shen, Yue; Wang, Fangqun

2012-04-01

In this paper, a new high reliability linear drive device, termed as stator-permanent-magnet tubular oscillating actuator (SPM-TOA), is proposed for artificial hearts (AHs). The key is to incorporate the concept of two independent phases into this linear AH device, hence achieving high reliability operation. The fault-tolerant teeth are employed to provide the desired decoupling phases in magnetic circuit. Also, as the magnets and the coils are located in the stator, the proposed SPM-TOA takes the definite advantages of robust mover and direct-drive capability. By using the time-stepping finite element method, the electromagnetic characteristics of the proposed SPM-TOA are analyzed, including magnetic field distributions, flux linkages, back- electromotive forces (back-EMFs) self- and mutual inductances, as well as cogging and thrust forces. The results confirm that the proposed SPM-TOA meets the dimension, weight, and force requirements of the AH drive device.

Dynamics of flows, fluctuations, and global instability under electrode biasing in a linear plasma device

NASA Astrophysics Data System (ADS)

Desjardins, T. R.; Gilmore, M.

2016-05-01

Grid biasing is utilized in a large-scale helicon plasma to modify an existing instability. It is shown both experimentally and with a linear stability analysis to be a hybrid drift-Kelvin-Helmholtz mode. At low magnetic field strengths, coherent fluctuations are present, while at high magnetic field strengths, the plasma is broad-band turbulent. Grid biasing is used to drive the once-coherent fluctuations to a broad-band turbulent state, as well as to suppress them. There is a corresponding change in the flow shear. When a high positive bias (10Te) is applied to the grid electrode, a large-scale ( n ˜/n ≈50 % ) is excited. This mode has been identified as the potential relaxation instability.

Precision Linear Actuator for Space Interferometry Mission (SIM) Siderostat Pointing

NASA Technical Reports Server (NTRS)

Cook, Brant; Braun, David; Hankins, Steve; Koenig, John; Moore, Don

2008-01-01

'SIM PlanetQuest will exploit the classical measuring tool of astrometry (interferometry) with unprecedented precision to make dramatic advances in many areas of astronomy and astrophysics'(1). In order to obtain interferometric data two large steerable mirrors, or Siderostats, are used to direct starlight into the interferometer. A gimbaled mechanism actuated by linear actuators is chosen to meet the unprecedented pointing and angle tracking requirements of SIM. A group of JPL engineers designed, built, and tested a linear ballscrew actuator capable of performing submicron incremental steps for 10 years of continuous operation. Precise, zero backlash, closed loop pointing control requirements, lead the team to implement a ballscrew actuator with a direct drive DC motor and a precision piezo brake. Motor control commutation using feedback from a precision linear encoder on the ballscrew output produced an unexpected incremental step size of 20 nm over a range of 120 mm, yielding a dynamic range of 6,000,000:1. The results prove linear nanometer positioning requires no gears, levers, or hydraulic converters. Along the way many lessons have been learned and will subsequently be shared.

Five-DOF innovative linear MagLev slider to account for pitch, tilt and load uncertainty

NASA Astrophysics Data System (ADS)

Kao, Yi-Ming; Tsai, Nan-Chyuan; Chiu, Hsin-Lin

2017-02-01

This paper is focused at position deviation regulation upon a slider by Fuzzy Sliding Mode Control (FSMC). Five Degrees Of Freedom (DOF) of position deviation are required to be regulated except for the direction (i.e., X-axis) in which the slider moves forward and backward. Totally 8 sets of Magnetic Actuators (MAs) and an Electro-Pneumatic Transducer (EPT) are employed to drive the slider carrying loads under the commands of FSMC. EPT is applied to adjust the pressure of compressed air to counterbalance the weight of slider itself. At first, the system dynamic model of slider, including load uncertainty and load position uncertainty, is established. Intensive computer simulations are undertaken to verify the validity of proposed control strategy. Finally, a prototype of realistic slider position deviation regulation system is successfully built up. According to the experiments by cooperation of pneumatic and magnetic control, the actual linear position deviations of slider can be regulated within ±8 μm and angular position deviations within ±1 mini-degrees. From the viewpoint of energy consumption, the applied currents to 8 sets of MAs are all below 1.2 A. To sum up, the closed-loop levitation system by cooperation of pneumatic and magnetic control is capable to account for load uncertainty and uncertainty of the standing position of load to be carried.

A two-layer linear piezoelectric micromotor.

PubMed

Li, Xiaotian; Ci, Penghong; Liu, Guoxi; Dong, Shuxiang

2015-03-01

A first bending (B1) mode two-layer piezoelectric ultrasonic linear micromotor has been developed for microoptics driving applications. The piezo-vibrator of the micromotor was composed of two small Pb(Zr,Ti)O3 (PZT-5) plates, with overall dimensions and mass of only 2.0 × 2.0 × 5.0 mm(3) and 0.2 g, respectively. The proposed micromotor could operate either in single-phase voltage (standing wave) mode or two-phase voltage (traveling wave) mode to drive a slider via friction force to provide bidirectional linear motion. A large thrust of up to 0.30 N, which corresponds to a high unit volume direct driving force of 15 mN/mm(3), and a linear movement velocity of up to 230 mm/s were obtained under an applied voltage of 80 Vpp at the B1 mode resonance frequency of 174 kHz.

Steering teens safe: a randomized trial of a parent-based intervention to improve safe teen driving.

PubMed

Peek-Asa, Corinne; Cavanaugh, Joseph E; Yang, Jingzhen; Chande, Vidya; Young, Tracy; Ramirez, Marizen

2014-07-31

Crashes are the leading cause of death for teens, and parent-based interventions are a promising approach. We assess the effectiveness of Steering Teens Safe, a parent-focused program to increase safe teen driving. Steering Teens Safe aimed to improve parental communication with teens about safe driving using motivational interviewing techniques in conjunction with 19 safe driving lessons. A randomized controlled trial involved 145 parent-teen dyads (70 intervention and 75 control). Intervention parents received a 45-minute session to learn the program with four follow-up phone sessions, a DVD, and a workbook. Control parents received a standard brochure about safe driving. Scores were developed to measure teen-reported quantity and quality of parental communication about safe driving. The main outcome measure was a previously validated Risky Driving Score reported by teens. Because the Score was highly skewed, a generalized linear model based on a gamma distribution was used for analysis. Intervention teens ranked their parent's success in talking about driving safety higher than control teens (p = 0.035) and reported that their parents talked about more topics (non-significant difference). The Risky Driving Score was 21% lower in intervention compared to control teens (85% CI = 0.60, 1.00). Interaction between communication quantity and the intervention was examined. Intervention teens who reported more successful communication had a 42% lower Risky Driving Score (95% CI = 0.37, 0.94) than control parents with less successful communication. This program had a positive although not strong effect, and it may hold the most promise in partnership with other programs, such as Driver's Education or Graduated Driver's License policies. ClinicalTrials.gov NCT01014923. Registered Nov. 16, 2009.

Development and Preliminary Testing of a High Precision Long Stroke Slit Change Mechanism for the SPICE Instrument

NASA Technical Reports Server (NTRS)

Paciotti, Gabriel; Humphries, Martin; Rottmeier, Fabrice; Blecha, Luc

2014-01-01

In the frame of ESA's Solar Orbiter scientific mission, Almatech has been selected to design, develop and test the Slit Change Mechanism of the SPICE (SPectral Imaging of the Coronal Environment) instrument. In order to guaranty optical cleanliness level while fulfilling stringent positioning accuracies and repeatability requirements for slit positioning in the optical path of the instrument, a linear guiding system based on a double flexible blade arrangement has been selected. The four different slits to be used for the SPICE instrument resulted in a total stroke of 16.5 mm in this linear slit changer arrangement. The combination of long stroke and high precision positioning requirements has been identified as the main design challenge to be validated through breadboard models testing. This paper presents the development of SPICE's Slit Change Mechanism (SCM) and the two-step validation tests successfully performed on breadboard models of its flexible blade support system. The validation test results have demonstrated the full adequacy of the flexible blade guiding system implemented in SPICE's Slit Change Mechanism in a stand-alone configuration. Further breadboard test results, studying the influence of the compliant connection to the SCM linear actuator on an enhanced flexible guiding system design have shown significant enhancements in the positioning accuracy and repeatability of the selected flexible guiding system. Preliminary evaluation of the linear actuator design, including a detailed tolerance analyses, has shown the suitability of this satellite roller screw based mechanism for the actuation of the tested flexible guiding system and compliant connection. The presented development and preliminary testing of the high-precision long-stroke Slit Change Mechanism for the SPICE Instrument are considered fully successful such that future tests considering the full Slit Change Mechanism can be performed, with the gained confidence, directly on a Qualification Model. The selected linear Slit Change Mechanism design concept, consisting of a flexible guiding system driven by a hermetically sealed linear drive mechanism, is considered validated for the specific application of the SPICE instrument, with great potential for other special applications where contamination and high precision positioning are dominant design drivers.

Miniature pipe crawler tractor

DOEpatents

McKay, Mark D.; Anderson, Matthew O.; Ferrante, Todd A.; Willis, W. David

2000-01-01

A pipe crawler tractor may comprise a half tractor assembly having a first base drive wheel, a second base drive wheel, and a top drive wheel. The drive wheels are mounted in spaced-apart relation so that the top drive wheel is positioned between the first and second base drive wheels. The mounting arrangement is also such that the first and second base drive wheels contact the inside surface of the pipe at respective first and second positions and so that the top drive wheel contacts the inside surface of the pipe at a third position, the third position being substantially diametrically opposed to the first and second positions. A control system connected to the half tractor assembly controls the rotation of the first base wheel, the second base wheel, and the top drive wheel to move the half tractor assembly within the pipe.

Externally resonated linear microvibromotor for microassembly

NASA Astrophysics Data System (ADS)

Saitou, Kazuhiro; Wou, Soungjin J.

1998-10-01

A new design of a linear micro vibromotor for on-substrate fine positioning of micro-scale components is presented where a micro linear slider is actuated by vibratory impacts exerted by micro cantilever impacters. These micro cantilever impacters are selectively resonated by shaking the entire substrate with a piezoelectric vibrator, requiring no need for built-in driving mechanisms such as electrostatic comb actuators as reported previously. This selective resonance of the micro cantilever impacters via an external vibration energy field provides with a very simple means of controlling forward and backward motion of the micro linear slider, facilitating assembly and disassembly of a micro component on a substrate. The double-V beam suspension design is employed in the micro cantilever impacters for larger displacement in the lateral direction while achieving higher stiffness in the transversal direction. An analytical model of the device is derived in order to obtain, through the Simulated Annealing algorithm, an optimal design which maximizes translation speed of the linear slider at desired external input frequencies. Prototypes of the externally-resonated linear micro vibromotor are fabricated using the three-layer polysilicon surface micro machining process provided by the MCNC MUMPS service.

Effects of pole flux distribution in a homopolar linear synchronous machine

NASA Astrophysics Data System (ADS)

Balchin, M. J.; Eastham, J. F.; Coles, P. C.

1994-05-01

Linear forms of synchronous electrical machine are at present being considered as the propulsion means in high-speed, magnetically levitated (Maglev) ground transportation systems. A homopolar form of machine is considered in which the primary member, which carries both ac and dc windings, is supported on the vehicle. Test results and theoretical predictions are presented for a design of machine intended for driving a 100 passenger vehicle at a top speed of 400 km/h. The layout of the dc magnetic circuit is examined to locate the best position for the dc winding from the point of view of minimum core weight. Measurements of flux build-up under the machine at different operating speeds are given for two types of secondary pole: solid and laminated. The solid pole results, which are confirmed theoretically, show that this form of construction is impractical for high-speed drives. Measured motoring characteristics are presented for a short length of machine which simulates conditions at the leading and trailing ends of the full-sized machine. Combination of the results with those from a cylindrical version of the machine make it possible to infer the performance of the full-sized traction machine. This gives 0.8 pf and 0.9 efficiency at 300 km/h, which is much better than the reported performance of a comparable linear induction motor (0.52 pf and 0.82 efficiency). It is therefore concluded that in any projected high-speed Maglev systems, a linear synchronous machine should be the first choice as the propulsion means.

Miniature pipe crawler tractor

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

McKay, M.D.; Anderson, M.O.; Ferrante, T.A.

2000-03-14

A pipe crawler tractor may comprise a half tractor assembly having a first base drive wheel, a second base drive wheel, and a top drive wheel. The drive wheels are mounted in spaced-apart relation so that the top drive wheel is positioned between the first and second base drive wheels. The mounting arrangement is also such that the first and second base drive wheels contact the inside surface of the pipe at respective first and second positions and so that the top drive wheel contacts the inside surface of the pipe at a third position, the third position being substantiallymore » diametrically opposed to the first and second positions. A control system connected to the half tractor assembly controls the rotation of the first base wheel, the second base wheel, and the top drive wheel to move the half tractor assembly within the pipe.« less

Modeling first impressions from highly variable facial images.

PubMed

Vernon, Richard J W; Sutherland, Clare A M; Young, Andrew W; Hartley, Tom

2014-08-12

First impressions of social traits, such as trustworthiness or dominance, are reliably perceived in faces, and despite their questionable validity they can have considerable real-world consequences. We sought to uncover the information driving such judgments, using an attribute-based approach. Attributes (physical facial features) were objectively measured from feature positions and colors in a database of highly variable "ambient" face photographs, and then used as input for a neural network to model factor dimensions (approachability, youthful-attractiveness, and dominance) thought to underlie social attributions. A linear model based on this approach was able to account for 58% of the variance in raters' impressions of previously unseen faces, and factor-attribute correlations could be used to rank attributes by their importance to each factor. Reversing this process, neural networks were then used to predict facial attributes and corresponding image properties from specific combinations of factor scores. In this way, the factors driving social trait impressions could be visualized as a series of computer-generated cartoon face-like images, depicting how attributes change along each dimension. This study shows that despite enormous variation in ambient images of faces, a substantial proportion of the variance in first impressions can be accounted for through linear changes in objectively defined features.

High-precision planar magnetic levitation

NASA Astrophysics Data System (ADS)

Kim, Won-Jong

1997-11-01

This thesis presents the design and implementation of a high-precision magnetically levitated stage with large planar motion capability. This stage is the first which is capable of providing all the motions required for photolithography in semiconductor manufacturing with only one moving part, namely the platen. The platen is driven in all six-degree-of-freedom motions with small adjustments for focusing and alignment and with large planar motions for positioning across the wafer surface. The underlying electromechanical modeling and analysis, mechanical and electrical design, and real-time control of such a high-precision planar magnetic levitator are presented. The platen is levitated without contact by four novel permanent-magnet linear motors that provide both suspension and drive forces. The linear motors consist of Halbach-type magnet arrays attached to the underside of the levitated platen, and coil sets attached to the fixed machine platform. Since all the motor coils are fixed, no wires need to be connected to the moving part. The platen mass of 5.6 kg is supported against gravity by the combined forces of the four motors. Each motor consumes about 5.4 W to lift the platen. Two of the motors drive the stage in the x-direction, and the two other motors drive in the y-direction. The motor forces are coordinated appropriately to control the remaining four degrees of freedom. The present design has a travel of 50 mm in x and y, a travel of 400 μm in z, and is capable of milliradian-scale rotations about each of these three axes. The stage position in the plane is measured with three laser interferometers with sub-nanometer resolution. The stage position out of the plane is measured by three capacitance probes with nanometer resolution. The stage operates with a position noise of 5 nm rms in x and y, and is demonstrating acceleration capabilities in excess of 10 m/s2 (1 g). The control bandwidth of the system is 50 Hz. This design can readily be scaled to travel on the order of 300 mm for the future needs of lithographic systems. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)

Extreme-UV scanning wafer and reticle stages

DOEpatents

Williams, Mark E.

2002-01-01

A stage for precise positioning of a chuck in three orthogonal linear axes and in three orthogonal rotation axes that includes first and second subassemblies. The a first subassembly includes (i) a monolithic mirror that supports the chuck wherein the monolithic mirror has at least two polished orthogonal faces for interferometric determination of the X, Y, and .THETA.z positions; (ii) a plurality of electromagnetic actuators that control fine positioning in all six axes and coarse positioning in one axis; (iii) a position sensor for measuring the vertical Z position of the monolithic mirror; and (iv) a Lorentz actuator, that includes magnet array, for effecting motion in the Y axis. The a second subassembly comprising a stepping axis beam over which the first subassembly is suspended, wherein the stepping axis beam includes a drive coil array for the Lorentz actuator. T the stage can also include a cable stage subassembly that is positioned a fixed distance away from the monolithic mirror and/or a mechanical zero reference for the first subassembly.

Impulsivity-like Traits and Risky Driving Behaviors among College Students

PubMed Central

Murphy, Elaine M.; Doane, Ashley N.

2017-01-01

The present study examined the predictive effects of five impulsivity-like traits (Premeditation, Perseverance, Sensation Seeking, Negative Urgency, and Positive Urgency) on driving outcomes (driving errors, driving lapses, driving violations, cell phone driving, traffic citations, and traffic collisions). With a convenience sample of 266 college student drivers, we found that each of the impulsivity-like traits was related to multiple risky driving outcomes. Positive Urgency (tendency to act impulsively when experiencing negative affect) was the most robust predictor of risky driving outcomes. Positive Urgency is a relatively newly conceptualized impulsivity-like trait that was not examined in the driving literature previously, suggesting a strong need to further examine its role as a personality trait related to risky driving. These findings generally support the multidimensional assessment of impulsivity-like traits, and they specifically support the addition of Positive Urgency to a list of risk factors for risky driving behaviors. PMID:23428428

Impulsivity-like traits and risky driving behaviors among college students.

PubMed

Pearson, Matthew R; Murphy, Elaine M; Doane, Ashley N

2013-04-01

The present study examined the predictive effects of five impulsivity-like traits (Premeditation, Perseverance, Sensation Seeking, Negative Urgency, and Positive Urgency) on driving outcomes (driving errors, driving lapses, driving violations, cell phone driving, traffic citations, and traffic collisions). With a convenience sample of 266 college student drivers, we found that each of the impulsivity-like traits was related to multiple risky driving outcomes. Positive Urgency (tendency to act impulsively when experiencing negative affect) was the most robust predictor of risky driving outcomes. Positive Urgency is a relatively newly conceptualized impulsivity-like trait that was not examined in the driving literature previously, suggesting a strong need to further examine its role as a personality trait related to risky driving. These findings generally support the multidimensional assessment of impulsivity-like traits, and they specifically support the addition of Positive Urgency to a list of risk factors for risky driving behaviors. Copyright © 2013 Elsevier Ltd. All rights reserved.

Preliminary results on noncollocated torque control of space robot actuators

NASA Technical Reports Server (NTRS)

Tilley, Scott W.; Francis, Colin M.; Emerick, Ken; Hollars, Michael G.

1989-01-01

In the Space Station era, more operations will be performed robotically in space in the areas of servicing, assembly, and experiment tending among others. These robots may have various sets of requirements for accuracy, speed, and force generation, but there will be design constraints such as size, mass, and power dissipation limits. For actuation, a leading motor candidate is a dc brushless type, and there are numerous potential drive trains each with its own advantages and disadvantages. This experiment uses a harmonic drive and addresses some inherent limitations, namely its backdriveability and low frequency structural resonances. These effects are controlled and diminished by instrumenting the actuator system with a torque transducer on the output shaft. This noncollocated loop is closed to ensure that the commanded torque is accurately delivered to the manipulator link. The actuator system is modelled and its essential parameters identified. The nonlinear model for simulations will include inertias, gearing, stiction, flexibility, and the effects of output load variations. A linear model is extracted and used for designing the noncollocated torque and position feedback loops. These loops are simulated with the structural frequency encountered in the testbed system. Simulation results are given for various commands in position. The use of torque feedback is demonstrated to yield superior performance in settling time and positioning accuracy. An experimental setup being finished consists of a bench mounted motor and harmonic drive actuator system. A torque transducer and two position encoders, each with sufficient resolution and bandwidth, will provide sensory information. Parameters of the physical system are being identified and matched to analytical predictions. Initial feedback control laws will be incorporated in the bench test equipment and various experiments run to validate the designs. The status of these experiments is given.

Design and reliability of a MEMS thermal rotary actuator.

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

Baker, Michael Sean; Corwin, Alex David

2007-09-01

A new rotary MEMS actuator has been developed and tested at Sandia National Laboratories that utilizes a linear thermal actuator as the drive mechanism. This actuator was designed to be a low-voltage, high-force alternative to the existing electrostatic torsional ratcheting actuator (TRA) [1]. The new actuator, called the Thermal Rotary Actuator (ThRA), is conceptually much simpler than the TRA and consists of a gear on a hub that is turned by a linear thermal actuator [2] positioned outside of the gear. As seen in Figure 1, the gear is turned through a ratcheting pawl, with anti-reverse pawls positioned around themore » gear for unidirectional motion (see Figure 1). A primary consideration in the design of the ThRA was the device reliability and in particular, the required one-to-one relationship between the ratcheting output motion and the electrical input signal. The electrostatic TRA design has been shown to both over-drive and under-drive relative to the number of input pulses [3]. Two different ThRA designs were cycle tested to measure the skip rate. This was done in an automated test setup by using pattern matching to measure the angle of rotation of the output gear after a defined number of actuation pulses. By measuring this gear angle over time, the number of skips can be determined. Figure 2 shows a picture of the ThRA during testing, with the pattern-matching features highlighted. In the first design tested, it was found that creep in the thermal actuator limited the number of skip-free cycles, as the rest position of the actuator would creep forward enough to prevent the counter-rotation pawls from fully engaging (Figure 3). Even with this limitation, devices were measured with up to 100 million cycles with no skipping. A design modification was made to reduce the operating temperature of the thermal actuator which has been shown in a previous study [2] to reduce the creep rate. In addition, changes were made to the drive ratchet design and actuation direction to increase the available output force. This new design was tested and shown to operate in one case out to greater than 360 million cycles without any skipping, after which the test was stopped without failure. The output force was also measured as a function of input voltage (Figure 4), and shown to be higher than the previous design. The maximum force shown in the figure is a limit of the gauge used, not the actuator itself. Continued work for this design will focus on understanding the actuator performance while driving a load, as all current tests were performed with no load on the output gear.« less

Rotor and bearing system for a turbomachine

DOEpatents

Lubell, Daniel; Weissert, Dennis

2006-09-26

A rotor and bearing system for a turbomachine. The turbomachine includes a drive shaft, an impeller positioned on the drive shaft, and a turbine positioned on the drive shaft proximate to the impeller. The bearing system comprises one gas journal bearing supporting the drive shaft between the impeller and the turbine. The area between the impeller and the turbine is an area of increased heat along the drive shaft in comparison to other locations along the drive shaft. The section of the drive shaft positioned between impeller and the turbine is also a section of the drive shaft that experiences increased stressed and load in the turbomachine. The inventive bearing machine system positions only one radial bearing in this area of increased stress and load.

Stable Spheromaks Sustained by Neutral Beam Injection

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

Fowler, T K; Jayakumar, R; McLean, H S

It is shown that spheromak equilibria, stable at zero-beta but departing from the Taylor state, could be sustained by non-inductive current drive at acceptable power levels. Stability to both ideal MHD and tearing modes is verified using the NIMROD code for linear stability analysis. Non-linear NIMROD calculations with non-inductive current drive and pressure effects could point the way to improved fusion reactors.

Engineering non-linear resonator mode interactions in circuit QED by continuous driving: Manipulation of a photonic quantum memory

NASA Astrophysics Data System (ADS)

Reagor, Matthew; Pfaff, Wolfgang; Heeres, Reinier; Ofek, Nissim; Chou, Kevin; Blumoff, Jacob; Leghtas, Zaki; Touzard, Steven; Sliwa, Katrina; Holland, Eric; Albert, Victor V.; Frunzio, Luigi; Devoret, Michel H.; Jiang, Liang; Schoelkopf, Robert J.

2015-03-01

Recent advances in circuit QED have shown great potential for using microwave resonators as quantum memories. In particular, it is possible to encode the state of a quantum bit in non-classical photonic states inside a high-Q linear resonator. An outstanding challenge is to perform controlled operations on such a photonic state. We demonstrate experimentally how a continuous drive on a transmon qubit coupled to a high-Q storage resonator can be used to induce non-linear dynamics of the resonator. Tailoring the drive properties allows us to cancel or enhance non-linearities in the system such that we can manipulate the state stored in the cavity. This approach can be used to either counteract undesirable evolution due to the bare Hamiltonian of the system or, ultimately, to perform logical operations on the state encoded in the cavity field. Our method provides a promising pathway towards performing universal control for quantum states stored in high-coherence resonators in the circuit QED platform.

Driving performance and driver discomfort in an elevated and standard driving position during a driving simulation.

PubMed

Smith, Jordan; Mansfield, Neil; Gyi, Diane; Pagett, Mark; Bateman, Bob

2015-07-01

The primary purposes of a vehicle driver's seat, is to allow them to complete the driving task comfortably and safely. Within each class of vehicle (e.g. passenger, commercial, industrial, agricultural), there is an expected driving position to which a vehicle cabin is designed. This paper reports a study that compares two driving positions, in relation to Light Commercial Vehicles (LCVs), in terms of driver performance and driver discomfort. In the 'elevated' driving position, the seat is higher than usually used in road vehicles; this is compared to a standard driving position replicating the layout for a commercially available vehicle. It is shown that for a sample of 12 drivers, the elevated position did not, in general, show more discomfort than the standard position over a 60 min driving simulation, although discomfort increased with duration. There were no adverse effects shown for emergency stop reaction time or for driver headway for the elevated posture compared to the standard posture. The only body part that showed greater discomfort for the elevated posture compared to the standard posture was the right ankle. A second experiment confirmed that for 12 subjects, a higher pedal stiffness eliminated the ankle discomfort problem. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Experimental examination of the effects of televised motor vehicle commercials on risk-positive attitudes, emotions and risky driving inclinations.

PubMed

Vingilis, Evelyn; Roseborough, James E W; Wiesenthal, David L; Vingilis-Jaremko, Larissa; Nuzzo, Valentina; Fischer, Peter; Mann, Robert E

2015-02-01

This study examined the short-term effects of risky driving motor vehicle television commercials on risk-positive attitudes, emotions and risky driving inclinations in video-simulated critical road traffic situations among males and females, within an experimental design. Participants were randomly assigned to one of three televised commercial advertising conditions embedded in a television show: a risky driving motor vehicle commercial condition, a non-risky driving motor vehicle commercial condition and a control non-motor vehicle commercial condition. Participants subsequently completed the Implicit Attitude Test (IAT) to measure risk-positive attitudes, Driver Thrill Seeking Scale (DTSS) to measure risk-positive emotions and the Vienna Risk-Taking Test - Traffic (WRBTV) to measure risky driving inclinations. ANOVA analyses indicated that type of commercial participants watched did not affect their performance on the IAT, DTSS or WRBTV. However, a main effect of heightened risk-positive emotions and risky driving inclinations was found for males. Despite public and governmental concern that risky driving motor vehicle commercials may increase the likelihood that people exposed to these commercials engage in risky driving, this experimental study found no immediate effect of brief exposure to a risky driving motor vehicle commercial on risk-positive attitudes, emotions or risky driving inclinations. Subsequent research should examine the effects of cumulative exposure to risky driving motor vehicle television commercials and print advertisements. Copyright © 2014 Elsevier Ltd. All rights reserved.

Magneto-capillary dynamics of amphiphilic Janus particles at curved liquid interfaces.

PubMed

Fei, Wenjie; Driscoll, Michelle M; Chaikin, Paul M; Bishop, Kyle J M

2018-05-11

A homogeneous magnetic field can exert no net force on a colloidal particle. However, by coupling the particle's orientation to its position on a curved interface, even static homogeneous fields can be used to drive rapid particle motions. Here, we demonstrate this effect using magnetic Janus particles with amphiphilic surface chemistry adsorbed at the spherical interface of a water drop in decane. Application of a static homogeneous field drives particle motion to the drop equator where the particle's magnetic moment can align parallel to the field. As explained quantitatively by a simple model, the effective magnetic force on the particle scales linearly with the curvature of the interface. For particles adsorbed on small droplets such as those found in emulsions, these magneto-capillary forces can far exceed those due to magnetic field gradients in both magnitude and range. This mechanism may be useful in creating highly responsive emulsions and foams stabilized by magnetic particles.

Driver Vision Based Perception-Response Time Prediction and Assistance Model on Mountain Highway Curve.

PubMed

Li, Yi; Chen, Yuren

2016-12-30

To make driving assistance system more humanized, this study focused on the prediction and assistance of drivers' perception-response time on mountain highway curves. Field tests were conducted to collect real-time driving data and driver vision information. A driver-vision lane model quantified curve elements in drivers' vision. A multinomial log-linear model was established to predict perception-response time with traffic/road environment information, driver-vision lane model, and mechanical status (last second). A corresponding assistance model showed a positive impact on drivers' perception-response times on mountain highway curves. Model results revealed that the driver-vision lane model and visual elements did have important influence on drivers' perception-response time. Compared with roadside passive road safety infrastructure, proper visual geometry design, timely visual guidance, and visual information integrality of a curve are significant factors for drivers' perception-response time.

Mirtazapine, a sedating antidepressant, and improved driving safety in patients with major depressive disorder: a prospective, randomized trial of 28 patients.

PubMed

Shen, Jianhua; Moller, Henry J; Wang, Xuehua; Chung, Sharon A; Shapiro, Gilla K; Li, Xiuying; Shapiro, Colin M

2009-03-01

The objectives of the study were to investigate the effects of mirtazapine, a sedating antidepressant, on driving safety in major depressive disorder (MDD) patients and to observe the effect of mirtazapine on daytime alertness. Twenty-eight patients who met the DSM-IV criteria for MDD completed the study in a university teaching hospital. Half of these patients took mirtazapine 30 mg at bedtime for 30 days. A computerized driving simulator test (DST) and the Maintenance of Wakefulness Test (MWT) were conducted at baseline and on days 2, 9, 16, and 30 after commencement of antidepressant use. Fourteen untreated depressed patients performed a DST and MWT at baseline and on days 2 and 9 to evaluate the possibility of a learning effect. Data collection was from June 2005 through January 2006. There were significant linear effects of the treatment on road position at All Trials (p = .018) and on the morning sessions at 10:00 a.m. (p < .001) and 12:00 p.m. (p = .022) and on the number of crashes at All Trials (p = .034) and the 4:00 p.m. session (p = .050) for the group on active treatment. Compared with the values at baseline, those of road position at 10:00 a.m. significantly improved on days 2 (p < .05), 9 (p < .01), 16 (p < .01) and 30 (p < .01) and road position at 12:00 p.m. significantly improved on days 16 (p < .05) and 30 (p < .05). The number of crashes significantly decreased on day 30 (p < .05). The untreated patients showed no improvement in performance in any of the measures, suggesting that the results are not due to a learning effect. A sedating antidepressant can increase driving safety in MDD patients. clinicaltrials.gov Identifier: NCT00385437. ©Copyright 2009 Physicians Postgraduate Press, Inc.

An approach to improving transporting velocity in the long-range ultrasonic transportation of micro-particles

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

Meng, Jianxin; Mei, Deqing, E-mail: meidq-127@zju.edu.cn; Yang, Keji

2014-08-14

In existing ultrasonic transportation methods, the long-range transportation of micro-particles is always realized in step-by-step way. Due to the substantial decrease of the driving force in each step, the transportation is lower-speed and stair-stepping. To improve the transporting velocity, a non-stepping ultrasonic transportation approach is proposed. By quantitatively analyzing the acoustic potential well, an optimal region is defined as the position, where the largest driving force is provided under the condition that the driving force is simultaneously the major component of an acoustic radiation force. To keep the micro-particle trapped in the optimal region during the whole transportation process, anmore » approach of optimizing the phase-shifting velocity and phase-shifting step is adopted. Due to the stable and large driving force, the displacement of the micro-particle is an approximately linear function of time, instead of a stair-stepping function of time as in the existing step-by-step methods. An experimental setup is also developed to validate this approach. Long-range ultrasonic transportations of zirconium beads with high transporting velocity were realized. The experimental results demonstrated that this approach is an effective way to improve transporting velocity in the long-range ultrasonic transportation of micro-particles.« less

Recent testing of a micro autonomous positioning system for multi-object instrumentation

NASA Astrophysics Data System (ADS)

Cochrane, W. A.; Atkinson, D. C.; Bailie, T. E. C.; Dickson, C.; Lim, T.; Luo, X.; Montgomery, D. M.; Schnetler, H.; Taylor, W. D.; Wilson, B.

2012-09-01

A multiple pick off mirror positioning sub-system has been developed as a solution for the deployment of mirrors within multi-object instrumentation such as the EAGLE instrument in the European Extremely Large Telescope (E-ELT). The positioning sub-system is a two wheeled differential steered friction drive robot with a footprint of approximately 20 x 20 mm. Controlled by RF communications there are two versions of the robot that exist. One is powered by a single cell lithium ion battery and the other utilises a power floor system. The robots use two brushless DC motors with 125:1 planetary gear heads for positioning in the coarse drive stages. A unique power floor allows the robots to be positioned at any location in any orientation on the focal plane. The design, linear repeatability tests, metrology and power continuity of the robot will be evaluated and presented in this paper. To gather photons from the objects of interest it is important to position POMs within a sphere of confusion of less than 10 μm, with an angular alignment better than 1 mrad. The robots potential of meeting these requirements will be described through the open-loop repeatability tests conducted with a Faro laser beam tracker. Tests have involved sending the robot step commands and automatically taking continuous measurements every three seconds. Currently the robot is capable of repeatedly travelling 233 mm within 0.307 mm at 5 mm/s. An analysis of the power floors reliability through the continuous monitoring of the voltage across the tracks with a Pico logger will also be presented.

A precision isotonic measuring system for isolated tissues.

PubMed

Mellor, P M

1984-12-01

An isotonic measuring system is described which utilizes an angular position transducer of the linear differential voltage transformer type. Resistance to corrosion, protection against the ingress of solutions, and ease of mounting and setting up were the mechanical objectives. Accuracy, linearity, and freedom from drift were essential requirements of the electrical specification. A special housing was designed to accommodate the transducer to overcome these problems. A control unit incorporating a power supply and electronic filtering components was made to serve up to four such transducers. The transducer output voltage is sufficiently high to drive directly even low sensitivity chart recorders. Constructional details and a circuit diagram are included. Fifty such transducers have been in use for up to four years in these laboratories. Examples of some of the published work done using this transducer system are referenced.

Arduino-based automation of a DNA extraction system.

PubMed

Kim, Kyung-Won; Lee, Mi-So; Ryu, Mun-Ho; Kim, Jong-Won

2015-01-01

There have been many studies to detect infectious diseases with the molecular genetic method. This study presents an automation process for a DNA extraction system based on microfluidics and magnetic bead, which is part of a portable molecular genetic test system. This DNA extraction system consists of a cartridge with chambers, syringes, four linear stepper actuators, and a rotary stepper actuator. The actuators provide a sequence of steps in the DNA extraction process, such as transporting, mixing, and washing for the gene specimen, magnetic bead, and reagent solutions. The proposed automation system consists of a PC-based host application and an Arduino-based controller. The host application compiles a G code sequence file and interfaces with the controller to execute the compiled sequence. The controller executes stepper motor axis motion, time delay, and input-output manipulation. It drives the stepper motor with an open library, which provides a smooth linear acceleration profile. The controller also provides a homing sequence to establish the motor's reference position, and hard limit checking to prevent any over-travelling. The proposed system was implemented and its functionality was investigated, especially regarding positioning accuracy and velocity profile.

Design and performance testing of an ultrasonic linear motor with dual piezoelectric actuators.

PubMed

Smithmaitrie, Pruittikorn; Suybangdum, Panumas; Laoratanakul, Pitak; Muensit, Nantakan

2012-05-01

In this work, design and performance testing of an ultrasonic linear motor with dual piezoelectric actuator patches are studied. The motor system consists of a linear stator, a pre-load weight, and two piezoelectric actuator patches. The piezoelectric actuators are bonded with the linear elastic stator at specific locations. The stator generates propagating waves when the piezoelectric actuators are subjected to harmonic excitations. Vibration characteristics of the linear stator are analyzed and compared with finite element and experimental results. The analytical, finite element, and experimental results show agreement. In the experiments, performance of the ultrasonic linear motor is tested. Relationships between velocity and pre-load weight, velocity and applied voltage, driving force and applied voltage, and velocity and driving force are reported. The design of the dual piezoelectric actuators yields a simpler structure with a smaller number of actuators and lower stator stiffness compared with a conventional design of an ultrasonic linear motor with fully laminated piezoelectric actuators.

Modeling first impressions from highly variable facial images

PubMed Central

Vernon, Richard J. W.; Sutherland, Clare A. M.; Young, Andrew W.; Hartley, Tom

2014-01-01

First impressions of social traits, such as trustworthiness or dominance, are reliably perceived in faces, and despite their questionable validity they can have considerable real-world consequences. We sought to uncover the information driving such judgments, using an attribute-based approach. Attributes (physical facial features) were objectively measured from feature positions and colors in a database of highly variable “ambient” face photographs, and then used as input for a neural network to model factor dimensions (approachability, youthful-attractiveness, and dominance) thought to underlie social attributions. A linear model based on this approach was able to account for 58% of the variance in raters’ impressions of previously unseen faces, and factor-attribute correlations could be used to rank attributes by their importance to each factor. Reversing this process, neural networks were then used to predict facial attributes and corresponding image properties from specific combinations of factor scores. In this way, the factors driving social trait impressions could be visualized as a series of computer-generated cartoon face-like images, depicting how attributes change along each dimension. This study shows that despite enormous variation in ambient images of faces, a substantial proportion of the variance in first impressions can be accounted for through linear changes in objectively defined features. PMID:25071197

49 CFR 571.102 - Standard No. 102; Transmission shift position sequence, starter interlock, and transmission...

Code of Federal Regulations, 2012 CFR

2012-10-01

... hour). S2. Application. This standard applies to passenger cars, multi-purpose passenger vehicles... positions on passenger cars. A neutral position shall be located between forward drive and reverse drive... ratio, one forward drive position shall provide a greater degree of engine braking than the highest...

49 CFR 571.102 - Standard No. 102; Transmission shift position sequence, starter interlock, and transmission...

Code of Federal Regulations, 2011 CFR

2011-10-01

... hour). S2. Application. This standard applies to passenger cars, multi-purpose passenger vehicles... positions on passenger cars. A neutral position shall be located between forward drive and reverse drive... ratio, one forward drive position shall provide a greater degree of engine braking than the highest...

49 CFR 571.102 - Standard No. 102; Transmission shift position sequence, starter interlock, and transmission...

Code of Federal Regulations, 2014 CFR

2014-10-01

... hour). S2. Application. This standard applies to passenger cars, multi-purpose passenger vehicles... positions on passenger cars. A neutral position shall be located between forward drive and reverse drive... ratio, one forward drive position shall provide a greater degree of engine braking than the highest...

49 CFR 571.102 - Standard No. 102; Transmission shift position sequence, starter interlock, and transmission...

Code of Federal Regulations, 2013 CFR

2013-10-01

... hour). S2. Application. This standard applies to passenger cars, multi-purpose passenger vehicles... positions on passenger cars. A neutral position shall be located between forward drive and reverse drive... ratio, one forward drive position shall provide a greater degree of engine braking than the highest...

An extended continuum model accounting for the driver's timid and aggressive attributions

NASA Astrophysics Data System (ADS)

Cheng, Rongjun; Ge, Hongxia; Wang, Jufeng

2017-04-01

Considering the driver's timid and aggressive behaviors simultaneously, a new continuum model is put forwarded in this paper. By applying the linear stability theory, we presented the analysis of new model's linear stability. Through nonlinear analysis, the KdV-Burgers equation is derived to describe density wave near the neutral stability line. Numerical results verify that aggressive driving is better than timid act because the aggressive driver will adjust his speed timely according to the leading car's speed. The key improvement of this new model is that the timid driving deteriorates traffic stability while the aggressive driving will enhance traffic stability. The relationship of energy consumption between the aggressive and timid driving is also studied. Numerical results show that aggressive driver behavior can not only suppress the traffic congestion but also reduce the energy consumption.

High-risk driving attitudes and everyday driving violations of car and racing enthusiasts in Ontario, Canada.

PubMed

Yildirim-Yenier, Zümrüt; Vingilis, Evelyn; Wiesenthal, David L; Mann, Robert E; Seeley, Jane

2015-01-01

Attitudes and individual difference variables of car and racing enthusiasts regarding high-risk behaviors of street racing and stunt driving have recently been investigated. Positive attitudes toward high-risk driving, personality variables such as driver thrill seeking, and other self-reported risky driving acts were associated with these behaviors. However, probable relationships among high-risk driving tendencies, everyday driving behaviors, and negative road safety outcomes have remained largely unexamined. This study aimed to investigate the associations among car and racing enthusiasts' high-risk driving attitudes, self-reported everyday driving violations (i.e., ordinary and aggressive violations), and self-reported negative outcomes (i.e., collisions and driving offense citations). A web-based survey was conducted with members and visitors of car club and racing websites in Ontario, Canada. Data were obtained from 366 participants. The questionnaire included 4 attitude measures-(1) attitudes toward new penalties for Ontario's Street Racers, Stunt and Aggressive Drivers Legislation; (2) attitudes toward new offenses of stunt driving under the same legislation; (3) general attitudes toward street racing and stunt driving; (4) comparison of street racing with other risky driving behaviors-self-reported driving violations (i.e., ordinary and aggressive violations); self-reported collisions and offense citations; and background and driving questions (e.g., age, driving frequency). Results revealed that attitudes toward stunt driving offenses negatively and general attitudes toward street racing and stunt driving positively predicted ordinary violations, which, in turn, predicted offense citations. Moreover, general attitudes toward street racing and stunt driving positively predicted aggressive violations, which, in turn, predicted offense citations. The findings indicate that positive high-risk driving attitudes may be transferring to driving violations in everyday traffic, which mediates driving offense citations.

The effects of positive emotion priming on self-reported reckless driving.

PubMed

Taubman-Ben-Ari, Orit

2012-03-01

Five studies examined the effects of positive emotion priming on the willingness to drive recklessly. In all five, young drivers were exposed to one of the following primes of positive affect: a positive mood story; happy memories; an exciting film; a relaxing film; or thoughts on the meaning in life. Following the prime, the participants were asked to report on their willingness to drive recklessly. The responses were compared to those of groups exposed either to neutral affect, another kind of positive affect, or negative affect priming. In two of the studies, participants were also asked to report on their driving styles (risky, anxious, angry, or careful) as a second dependent variable. Positive affect, especially in the form of arousal, was found to be related to higher willingness to drive recklessly. Although men tended to report higher intentions to drive recklessly, men and women did not react differently to the emotional induction. Most interestingly, positive emotions of a relaxing nature, as well as thinking about the meaning in life, lowered the willingness to engage in risky driving. The discussion emphasizes the importance of looking for new ways to use positive emotions effectively in road safety interventions, and considers the practical implications of the studies. Copyright © 2011 Elsevier Ltd. All rights reserved.

Continuously varying skin potentials elicited by sinusoidally varying electric shock potentials

NASA Technical Reports Server (NTRS)

Senders, J. W.; Senders, V. L.; Tursky, B.

1973-01-01

An investigation was carried out to determine whether a form of quasi-linear systems analysis can be applied to electrodormal responses to yield new insights into the nature of the response mechanisms and their interrelationships. The response investigated was the electrodermal response (galvanic skin potential, GSP) as elicited by an electric shock stimulus applied to the skin. The response subsequent to this stimulation was examined and its characteristics measured. A series of experimental runs on three Ss was accomplished, using sinusoidal modulation envelopes of frequencies. Results showed that it was possible to drive the GSP and to achieve relatively high coherence between the driving frequency and the response itself. The analysis was limited to Fourier analysis of the response in order to determine the relative energies at the driving frequency and at successive harmonics of that driving frequency, and correlational analysis in order to determine the degree of linear relationship between the driving frequency and the driven response.

Micromachined electrostatic vertical actuator

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

Lee, Abraham P.; Sommargren, Gary E.; McConaghy, Charles F.

A micromachined vertical actuator utilizing a levitational force, such as in electrostatic comb drives, provides vertical actuation that is relatively linear in actuation for control, and can be readily combined with parallel plate capacitive position sensing for position control. The micromachined electrostatic vertical actuator provides accurate movement in the sub-micron to micron ranges which is desirable in the phase modulation instrument, such as optical phase shifting. For example, compact, inexpensive, and position controllable micromirrors utilizing an electrostatic vertical actuator can replace the large, expensive, and difficult-to-maintain piezoelectric actuators. A thirty pound piezoelectric actuator with corner cube reflectors, as utilized inmore » a phase shifting diffraction interferometer can be replaced with a micromirror and a lens. For any very precise and small amplitudes of motion` micromachined electrostatic actuation may be used because it is the most compact in size, with low power consumption and has more straightforward sensing and control options.« less

Micromachined electrostatic vertical actuator

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

Lee, A.P.; Sommargren, G.E.; McConaghy, C.F.

A micromachined vertical actuator utilizing a levitational force, such as in electrostatic comb drives, provides vertical actuation that is relatively linear in actuation for control, and can be readily combined with parallel plate capacitive position sensing for position control. The micromachined electrostatic vertical actuator provides accurate movement in the sub-micron to micron ranges which is desirable in the phase modulation instrument, such as optical phase shifting. For example, compact, inexpensive, and position controllable micromirrors utilizing an electrostatic vertical actuator can replace the large, expensive, and difficult-to-maintain piezoelectric actuators. A thirty pound piezoelectric actuator with corner cube reflectors, as utilized inmore » a phase shifting diffraction interferometer can be replaced with a micromirror and a lens. For any very precise and small amplitudes of motion, micromachined electrostatic actuation may be used because it is the most compact in size, with low power consumption and has more straightforward sensing and control options.« less

Characteristics of the First Longitudinal-Fourth Bending Mode Linear Ultrasonic Motors

NASA Astrophysics Data System (ADS)

Park, Taegone; Kim, Beomjin; Kim, Myong-Ho; Uchino, Kenji

2002-11-01

Linear ultrasonic motors using a combination of the first longitudinal mode and the fourth bending mode were designed and fabricated. The driving characteristics of the motors, which were composed of a straight metal bar bonded with piezoelectric ceramic vibrators as a driving element, were measured. Unimorph and bimorph ceramic vibrators were attached on three kinds of metal bars for constructing the stators of the linear motors. As results, motors made with the bimorph ceramic vibrators had higher velocity than motors of the unimorph vibrators. As a metal bar for stator, magnesium alloy, which has lower elastic coefficient than aluminum alloy, was better for the motors.

Optical vibration measurement of mechatronics devices

NASA Astrophysics Data System (ADS)

Yanabe, Shigeo

1993-09-01

An optical vibration measuring system which enables to detect both linear and angular displacement of 25 nm and 5 prad was developed. The system is mainly composed of a He-Ne laser, a displacement detecting photo-diode and lenses, and has linear and angular displacement magnification mechanism using two different principles of optical lever. The system was applied to measure vibrational characteristics of magnetic head slider of hard disk drives and to measure stator teeth driving velocities of ultrasonic motor.

Linear-drive cryocoolers for the Department of Defense standard advanced dewar assembly (SADA)

NASA Astrophysics Data System (ADS)

Tate, Garin S.

2005-05-01

The Standard Advanced Dewar Assembly (SADA) is the critical module in the Department of Defense (DoD) standardization of scanning second-generation thermal imaging systems. The DoD has established a family of SADAs to fulfill a range of performance requirements for various platforms. The SADA consists of the Infrared Focal Plane Array (IRFPA), Dewar, Command & Control Electronics (C&CE), and the cryogenic cooler, and is used in platforms such as the Apache helicopter, the M1A2 Abrams main battle tank, the M2 Bradley Infantry Fighting Vehicle, and the Javelin Command Launch Unit (CLU). In support of the family of SADAs, the DoD defined a complementary family of tactical linear drive cryocoolers. The Stirling cycle linear drive cryocoolers are utilized to cool the Infrared Focal Plane Arrays (IRFPAs) in the SADAs. These coolers are required to have low input power, a quick cool-down time, low vibration output, low audible noise, and a higher reliability than currently fielded rotary coolers. These coolers must also operate in a military environment with its inherent high vibration level and temperature extremes. This paper will (1) outline the characteristics of each cryocooler, (2) present the status and results of qualification tests, (3) present the status of production efforts, and (4) present the status of efforts to increase linear drive cooler reliability.

Drive Control of an Electric Vehicle by a Non-linear Controller

NASA Astrophysics Data System (ADS)

Mubin, Marizan; Ouchi, Shigeto; Anabuki, Masatoshi; Hirata, Hiroshi

The driving force of automobiles is transmitted by the frictional force between the tires and the road surface. This frictional force is a function of the weight of the car-body and the friction coefficient μ between the tires and the road surface. The friction coefficient μ is also a function of the following parameters: the slip ratio λ determined by the car-body speed and the wheel speed, and the condition of the road surface. Slippage of automobiles which causes much damage often occurs during accelerating and braking. In this paper, we propose a new drive control system which has an effect on acceleration and braking. In the drive control system, a non-linear controller designed by using a Lyapunov function is used. This non-linear controller has two functions: first one is μ control which moves the car-body, another one is λ control. The controller is designed in order that μ and λ work at noslip and with slip respectively. As another controller, a disturbance observer is used for estimating the car-body speed which is difficult to be measured. Then, this lead to the proof of the stability condition of the combined system which consists of two controllers: the non-linear controller and the disturbance observer. Finally, the effectiveness of this control system is proved by a very satisfactory simulation and experimental results for two cases.

Novice drivers' individual trajectories of driver behavior over the first three years of driving.

PubMed

Roman, Gabriela D; Poulter, Damian; Barker, Edward; McKenna, Frank P; Rowe, Richard

2015-09-01

Identifying the changes in driving behavior that underlie the decrease in crash risk over the first few months of driving is key to efforts to reduce injury and fatality risk in novice drivers. This study represented a secondary data analysis of 1148 drivers who participated in the UK Cohort II study. The Driver Behavior Questionnaire was completed at 6 months and 1, 2 and 3 years after licensure. Linear latent growth models indicated significant increases across development in all four dimensions of aberrant driving behavior under scrutiny: aggressive violations, ordinary violations, errors and slips. Unconditional and conditional latent growth class analyses showed that the observed heterogeneity in individual trajectories was explained by the presence of multiple homogeneous groups of drivers, each exhibiting specific trajectories of aberrant driver behavior. Initial levels of aberrant driver behavior were important in identifying sub-groups of drivers. All classes showed positive slopes; there was no evidence of a group of drivers whose aberrant behavior decreased over time that might explain the decrease in crash involvement observed over this period. Male gender and younger age predicted membership of trajectories with higher levels of aberrant behavior. These findings highlight the importance of early intervention for improving road safety. We discuss the implications of our findings for understanding the behavioral underpinnings of the decrease in crash involvement observed in the early months of driving. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Autonomous Vision Navigation for Spacecraft in Lunar Orbit

NASA Astrophysics Data System (ADS)

Bader, Nolan A.

NASA aims to achieve unprecedented navigational reliability for the first manned lunar mission of the Orion spacecraft in 2023. A technique for accomplishing this is to integrate autonomous feature tracking as an added means of improving position and velocity estimation. In this thesis, a template matching algorithm and optical sensor are tested onboard three simulated lunar trajectories using linear covariance techniques under various conditions. A preliminary characterization of the camera gives insight into its ability to determine azimuth and elevation angles to points on the surface of the Moon. A navigation performance analysis shows that an optical camera sensor can aid in decreasing position and velocity errors, particularly in a loss of communication scenario. Furthermore, it is found that camera quality and computational capability are driving factors affecting the performance of such a system.

Drive reconfiguration mechanism for tracked robotic vehicle

DOEpatents

Willis, W. David

2000-01-01

Drive reconfiguration apparatus for changing the configuration of a drive unit with respect to a vehicle body may comprise a guide system associated with the vehicle body and the drive unit which allows the drive unit to rotate about a center of rotation that is located at about a point where the drive unit contacts the surface being traversed. An actuator mounted to the vehicle body and connected to the drive unit rotates the drive unit about the center of rotation between a first position and a second position.

Integrated Optoelectronic Position Sensor for Scanning Micromirrors.

PubMed

Cheng, Xiang; Sun, Xinglin; Liu, Yan; Zhu, Lijun; Zhang, Xiaoyang; Zhou, Liang; Xie, Huikai

2018-03-26

Scanning micromirrors have been used in a wide range of areas, but many of them do not have position sensing built in, which significantly limits their application space. This paper reports an integrated optoelectronic position sensor (iOE-PS) that can measure the linear displacement and tilting angle of electrothermal MEMS (Micro-electromechanical Systems) scanning mirrors. The iOE-PS integrates a laser diode and its driving circuits, a quadrant photo-detector (QPD) and its readout circuits, and a band-gap reference all on a single chip, and it has been fabricated in a standard 0.5 μm CMOS (Complementary Metal Oxide Semiconductor) process. The footprint of the iOE-PS chip is 5 mm × 5 mm. Each quadrant of the QPD has a photosensitive area of 500 µm × 500 µm and the spacing between adjacent quadrants is 500 μm. The iOE-PS chip is simply packaged underneath of an electrothermally-actuated MEMS mirror. Experimental results show that the iOE-PS has a linear response when the MEMS mirror plate moves vertically between 2.0 mm and 3.0 mm over the iOE-PS chip or scans from -5 to +5°. Such MEMS scanning mirrors integrated with the iOE-PS can greatly reduce the complexity and cost of the MEMS mirrors-enabled modules and systems.

Viscoelastic-coupling model for the earthquake cycle driven from below

USGS Publications Warehouse

Savage, J.C.

2000-01-01

In a linear system the earthquake cycle can be represented as the sum of a solution which reproduces the earthquake cycle itself (viscoelastic-coupling model) and a solution that provides the driving force. We consider two cases, one in which the earthquake cycle is driven by stresses transmitted along the schizosphere and a second in which the cycle is driven from below by stresses transmitted along the upper mantle (i.e., the schizosphere and upper mantle, respectively, act as stress guides in the lithosphere). In both cases the driving stress is attributed to steady motion of the stress guide, and the upper crust is assumed to be elastic. The surface deformation that accumulates during the interseismic interval depends solely upon the earthquake-cycle solution (viscoelastic-coupling model) not upon the driving source solution. Thus geodetic observations of interseismic deformation are insensitive to the source of the driving forces in a linear system. In particular, the suggestion of Bourne et al. [1998] that the deformation that accumulates across a transform fault system in the interseismic interval is a replica of the deformation that accumulates in the upper mantle during the same interval does not appear to be correct for linear systems.

Phase-matched generation of coherent soft and hard X-rays using IR lasers

DOEpatents

Popmintchev, Tenio V.; Chen, Ming-Chang; Bahabad, Alon; Murnane, Margaret M.; Kapteyn, Henry C.

2013-06-11

Phase-matched high-order harmonic generation of soft and hard X-rays is accomplished using infrared driving lasers in a high-pressure non-linear medium. The pressure of the non-linear medium is increased to multi-atmospheres and a mid-IR (or higher) laser device provides the driving pulse. Based on this scaling, also a general method for global optimization of the flux of phase-matched high-order harmonic generation at a desired wavelength is designed.

Electrostatic Microactuators for Precise Positioning of Neural Microelectrodes

PubMed Central

Muthuswamy, Jit; Okandan, Murat; Jain, Tilak; Gilletti, Aaron

2006-01-01

Microelectrode arrays used for monitoring single and multineuronal action potentials often fail to record from the same population of neurons over a period of time likely due to micromotion of neurons away from the microelectrode, gliosis around the recording site and also brain movement due to behavior. We report here novel electrostatic microactuated microelectrodes that will enable precise repositioning of the microelectrodes within the brain tissue. Electrostatic comb-drive microactuators and associated microelectrodes are fabricated using the SUMMiT V™ (Sandia's Ultraplanar Multilevel MEMS Technology) process, a five-layer polysilicon micromachining technology of the Sandia National labs, NM. The microfabricated microactuators enable precise bidirectional positioning of the microelectrodes in the brain with accuracy in the order of 1 μm. The microactuators allow for a linear translation of the microelectrodes of up to 5 mm in either direction making it suitable for positioning microelectrodes in deep structures of a rodent brain. The overall translation was reduced to approximately 2 mm after insulation of the microelectrodes with epoxy for monitoring multiunit activity. The microactuators are capable of driving the microelectrodes in the brain tissue with forces in the order of several micro-Newtons. Single unit recordings were obtained from the somatosensory cortex of adult rats in acute experiments demonstrating the feasibility of this technology. Further optimization of the insulation, packaging and interconnect issues will be necessary before this technology can be validated in long-term experiments. PMID:16235660

Design of a portable artificial heart drive system based on efficiency analysis.

PubMed

Kitamura, T

1986-11-01

This paper discusses a computer simulation of a pneumatic portable piston-type artificial heart drive system with a linear d-c-motor. The purpose of the design is to obtain an artificial heart drive system with high efficiency and small dimensions to enhance portability. The design employs two factors contributing the total efficiency of the drive system. First, the dimensions of the pneumatic actuator were optimized under a cost function of the total efficiency. Second, the motor performance was studied in terms of efficiency. More than 50 percent of the input energy of the actuator with practical loads is consumed in the armature circuit in all linear d-c-motors with brushes. An optimal design is: the piston cross-sectional area of 10.5 cm2 cylinder longitudinal length of 10 cm. The total efficiency could be up to 25 percent by improving the gasket to reduce the frictional force.

Real-time multi-target ranging based on chaotic polarization laser radars in the drive-response VCSELs.

PubMed

Zhong, Dongzhou; Xu, Geliang; Luo, Wei; Xiao, Zhenzhen

2017-09-04

According to the principle of complete chaos synchronization and the theory of Hilbert phase transformation, we propose a novel real-time multi-target ranging scheme by using chaotic polarization laser radar in the drive-response vertical-cavity surface-emitting lasers (VCSELs). In the scheme, to ensure each polarization component (PC) of the master VCSEL (MVCSEL) to be synchronized steadily with that of the slave VCSEL, the output x-PC and y-PC from the MVCSEL in the drive system and those in the response system are modulated by the linear electro-optic effect simultaneously. Under this condition, by simulating the influences of some key parameters of the system on the synchronization quality and the relative errors of the two-target ranging, related operating parameters can be optimized. The x-PC and the y-PC, as two chaotic radar sources, are used to implement the real-time ranging for two targets. It is found that the measured distances of the two targets at arbitrary position exhibit strong real-time stability and only slight jitter. Their resolutions are up to millimeters, and their relative errors are very small and less than 2.7%.

Integrated Fault Diagnosis Algorithm for Motor Sensors of In-Wheel Independent Drive Electric Vehicles.

PubMed

Jeon, Namju; Lee, Hyeongcheol

2016-12-12

An integrated fault-diagnosis algorithm for a motor sensor of in-wheel independent drive electric vehicles is presented. This paper proposes a method that integrates the high- and low-level fault diagnoses to improve the robustness and performance of the system. For the high-level fault diagnosis of vehicle dynamics, a planar two-track non-linear model is first selected, and the longitudinal and lateral forces are calculated. To ensure redundancy of the system, correlation between the sensor and residual in the vehicle dynamics is analyzed to detect and separate the fault of the drive motor system of each wheel. To diagnose the motor system for low-level faults, the state equation of an interior permanent magnet synchronous motor is developed, and a parity equation is used to diagnose the fault of the electric current and position sensors. The validity of the high-level fault-diagnosis algorithm is verified using Carsim and Matlab/Simulink co-simulation. The low-level fault diagnosis is verified through Matlab/Simulink simulation and experiments. Finally, according to the residuals of the high- and low-level fault diagnoses, fault-detection flags are defined. On the basis of this information, an integrated fault-diagnosis strategy is proposed.

Traction Drives for Zero Stick-Slip Robots, and Reaction Free, Momentum Balanced Systems

NASA Technical Reports Server (NTRS)

Anderson, William J.; Shipitalo, William; Newman, Wyatt

1995-01-01

Two differential (dual input, single output) drives (a roller-gear and a pure roller), and a momentum balanced (single input, dual output) drive (pure roller ) were designed, fabricated, and tested. The differential drives are each rated at 295 rad/sec (2800 rpm) input speed, 450 N-m (4,000 in-lbf) output torque. The momentum balanced drive is rated at 302 rad/sec (2880 rpm) input speed, and dual output torques of 434N-m (3840 in-lbf). The Dual Input Differential Roller-Gear Drive (DC-700) has a planetary roller-gear system with a reduction ratio (one input driving the output with the second input fixed) of 29.23: 1. The Dual Input Differential Roller Drive (DC-500) has a planetary roller system with a reduction ratio of approximately 24:1. Each of the differential drives features dual roller-gear or roller arrangements consisting of a sun, four first row planets, four second row planets, and a ring. The Momentum Balanced (Grounded Ring) Drive (DC-400) has a planetary roller system with a reduction ratio of 24:1 with both outputs counterrotating at equal speed. Its single roller cluster consists of a sun, five first and five second row planets, a roller cage or spider and a ring. Outputs are taken from both the roller cage and the ring which counterrotate. Test results reported for all three drives include angular and torque ripple (linearity and cogging), viscous and Coulomb friction, and forward and reverse power efficiency. Of the two differential drives, the Differential Roller Drive had better linearity and less cogging than did the Differential Roller-Gear Drive, but it had higher friction and lower efficiency (particularly at low power throughput levels). Use of full preloading rather than a variable preload system in the Differential Roller Drive assessed a heavy penalty in part load efficiency. Maximum measured efficiency (ratio of power out to power in) was 95% for the Differential Roller-Gear Drive and 86% for the Differential Roller Drive. The Momentum Balanced (Grounded Ring) Drive performed as expected kinematically. Reduction r-atios to the two counterrotating outputs (design nominal=24:1) were measured to be 23.98:1 and 24.12:1 at zero load.. At 25ONm (2200 in-lbf) output torque the ratio changed 2% due to roller creep. This drive was the smoothest of all three as determined from linearity and cogging tests, and maximum measured efficiency (ratio of power out to power in) was 95%. The disadvantages of full preloading as comvared to variable preload were apparent in this drive as in the Differential Roller Drive. Efficiencies at part load were low, but improved dramatically with increases in torque. These were consistent with friction measurements which indicated losses primarily from Coulomb friction. The initial preload level setting was low so roller slip was encountered at higher torques during testing.

Job demands and driving anger: The roles of emotional exhaustion and work engagement.

PubMed

Li, Feng; Wang, Guangxi; Li, Yongjuan; Zhou, Ronggang

2017-01-01

This study aimed to examine the effects of both hindrance and challenge demands on driving anger within the framework of the job demands-resources (JD-R) model. We collected self-reported data from 411 office workers driving to and from work each day in five cities in China. The results from a structural equation modeling analysis indicated that both hindrance and challenge demands were positively related to emotional exhaustion, which was in turn positively correlated with driving anger. Moreover, work engagement was positively correlated with driving anger. Implications of the present findings regarding both the JD-R model and driving safety research are discussed. Copyright © 2016 Elsevier Ltd. All rights reserved.

An extended heterogeneous car-following model accounting for anticipation driving behavior and mixed maximum speeds

NASA Astrophysics Data System (ADS)

Sun, Fengxin; Wang, Jufeng; Cheng, Rongjun; Ge, Hongxia

2018-02-01

The optimal driving speeds of the different vehicles may be different for the same headway. In the optimal velocity function of the optimal velocity (OV) model, the maximum speed vmax is an important parameter determining the optimal driving speed. A vehicle with higher maximum speed is more willing to drive faster than that with lower maximum speed in similar situation. By incorporating the anticipation driving behavior of relative velocity and mixed maximum speeds of different percentages into optimal velocity function, an extended heterogeneous car-following model is presented in this paper. The analytical linear stable condition for this extended heterogeneous traffic model is obtained by using linear stability theory. Numerical simulations are carried out to explore the complex phenomenon resulted from the cooperation between anticipation driving behavior and heterogeneous maximum speeds in the optimal velocity function. The analytical and numerical results all demonstrate that strengthening driver's anticipation effect can improve the stability of heterogeneous traffic flow, and increasing the lowest value in the mixed maximum speeds will result in more instability, but increasing the value or proportion of the part already having higher maximum speed will cause different stabilities at high or low traffic densities.

Maintenance of working capacity of movement mechanism of load trolley with linear traction electric drive of bridge type crane.

NASA Astrophysics Data System (ADS)

Goncharov, K. A.; Denisov, I. A.

2017-10-01

The article considers the influence of the air gap size between the linear motor elements on the stability of the traction drive of the movement mechanism of the trolley of the bridge type crane. The main factors affecting the air gap size and the causes of their occurrence are described. The technique of calculating the magnitude of air gap variation is described in relation to the general deformation of the crane metal structure. Recommendations on the need for installation of additional equipment for load trolleys of various designs are given. The optimal values of the length of the trolley base are proposed. Observance of these values ensures normal operation of the traction drive.

Design and fabrication of a long-life Stirling cycle cooler for space application. Phase 3: Prototype model

NASA Technical Reports Server (NTRS)

Keung, C.; Patt, P. J.; Starr, M.; Sweet, R. C.; Bourdillon, L. A.; Figueroa, R.; Hartmann, M.; Mcfarlane, R.

1990-01-01

A second-generation, Stirling-cycle cryocooler (cryogenic refrigerator) for space applications, with a cooling capacity of 5 watts at 65 K, was recently completed. The refrigerator, called the Prototype Model, was designed with a goal of 5 year life with no degradation in cooling performance. The free displacer and free piston of the refrigerator are driven directly by moving-magnet linear motors with the moving elements supported by active magnetic bearings. The use of clearance seals and the absence of outgassing material in the working volume of the refrigerator enable long-life operation with no deterioration in performance. Fiber-optic sensors detect the radial position of the shafts and provide a control signal for the magnetic bearings. The frequency, phase, stroke, and offset of the compressor and expander are controlled by signals from precision linear position sensors (LVDTs). The vibration generated by the compressor and expander is cancelled by an active counter balance which also uses a moving-magnet linear motor and magnetic bearings. The driving signal for the counter balance is derived from the compressor and expander position sensors which have wide bandwidth for suppression of harmonic vibrations. The efficiency of the three active members, which operate in a resonant mode, is enhanced by a magnetic spring in the expander and by gas springs in the compressor and counterbalance. The cooling was achieved with a total motor input power of 139 watts. The magnetic-bearing stiffness was significantly increased from the first-generation cooler to accommodate shuttle launch vibrations.

Bidirectional drive and brake mechanism

NASA Technical Reports Server (NTRS)

Swan, Scott A. (Inventor)

1991-01-01

A space transport vehicle is disclosed as including a body which is arranged to be movably mounted on an elongated guide member disposed in outer space and driven therealong. A drive wheel is mounted on a drive shaft and arranged to be positioned in rolling engagement with the elongated guide carrying the vehicle. A brake member is arranged on the drive shaft for movement into and out of engagement with an adjacent surface of the drive wheel. An actuator is mounted on the body to be manually moved back and forth between spaced positions in an arc of movement. A ratchet-and-pawl mechanism is arranged to operate upon movements of the actuator in one direction between first and second positions for coupling the actuator to the drive wheel to incrementally rotate the wheel in one rotational direction and to operate upon movements of the actuator in the opposite direction for uncoupling the actuator from the wheel. The brake member is threadedly coupled to the drive shaft in order that the brake member will be operated only when the actuator is moved on beyond its first and second positions for shifting the brake member along the drive shaft and into frictional engagement with the adjacent surface on the drive wheel.

Correlation between Driver Subjective Fatigue and Bus Lateral Position in a Driving Simulator.

PubMed

Gharagozlou, Faramarz; Mazloumi, Adel; Saraji, Gebraeil Nasl; Nahvi, Ali; Ashouri, Mohammadreza; Mozaffari, Hamed

2015-08-01

Driver fatigue as a leading cause of death in the transportation industry can impair the driving performance in long-distance driving task. Studies on the links of driver subjective fatigue and the bus lateral position are still an exploratory issue that requires further investigation. This study aimed to determine the correlation between the driver subjective fatigue and the bus lateral position in a driving simulator. This descriptive-analytical research was conducted on 30 professional male bus drivers participated in a two-hour driving session. The driver subjective fatigue was assessed by the Fatigue Visual Analogue Scale (F-VAS) at 10-min intervals. Simultaneously, the performance measures of lane drifting as the mean and standard deviation of the bus lateral position (SDLP) were calculated during the simulated driving task. Descriptive statistics and the Spearman correlation coefficient were used to describe and analyze the data. Fatigue levels had an increasing trend as the time-on-task of driving increased. Time-on-task of driving had the greatest effect on the fatigue self-evaluation (r = 0.605, p < 0.0001). The results showed a significant correlation between fatigue self-evaluation and bus lateral position (r = 0.567, p < 0.0001). As the time of driving increased, driving performance was affected adversely, as shown by the increase in the SDLP. Even so, the effect of individual differences on driving performance should not be overlooked. This work concludes that predicting the state of a driver fatigue based on the group mean data has some complications for any application.

Correlation between Driver Subjective Fatigue and Bus Lateral Position in a Driving Simulator

PubMed Central

Gharagozlou, Faramarz; Mazloumi, Adel; Saraji, Gebraeil Nasl; Nahvi, Ali; Ashouri, Mohammadreza; Mozaffari, Hamed

2015-01-01

Background: Driver fatigue as a leading cause of death in the transportation industry can impair the driving performance in long-distance driving task. Studies on the links of driver subjective fatigue and the bus lateral position are still an exploratory issue that requires further investigation. This study aimed to determine the correlation between the driver subjective fatigue and the bus lateral position in a driving simulator. Methods: This descriptive-analytical research was conducted on 30 professional male bus drivers participated in a two-hour driving session. The driver subjective fatigue was assessed by the Fatigue Visual Analogue Scale (F-VAS) at 10-min intervals. Simultaneously, the performance measures of lane drifting as the mean and standard deviation of the bus lateral position (SDLP) were calculated during the simulated driving task. Descriptive statistics and the Spearman correlation coefficient were used to describe and analyze the data. Results: Fatigue levels had an increasing trend as the time-on-task of driving increased. Time-on-task of driving had the greatest effect on the fatigue self-evaluation (r = 0.605, p < 0.0001). The results showed a significant correlation between fatigue self-evaluation and bus lateral position (r = 0.567, p < 0.0001). Conclusion: As the time of driving increased, driving performance was affected adversely, as shown by the increase in the SDLP. Even so, the effect of individual differences on driving performance should not be overlooked. This work concludes that predicting the state of a driver fatigue based on the group mean data has some complications for any application. PMID:26396734

Development of a bi-directional standing wave linear piezoelectric actuator with four driving feet.

PubMed

Liu, Yingxiang; Shi, Shengjun; Li, Chunhong; Chen, Weishan; Wang, Liang; Liu, Junkao

2018-03-01

A bi-directional standing wave linear piezoelectric ultrasonic actuator with four driving feet is proposed in this work. Two sandwich type transducers operated in longitudinal-bending hybrid modes are set parallelly. The working mode of the transducer is not simple hybrid vibrations of a longitudinal one and a bending one, but a special coupling vibration mode contained both longitudinal and bending components. Two transducers with the same structure and unsymmetrical boundary conditions are set parallelly to accomplish the bi-directional driving: the first transducer can push the runner forward, while the other one produces the backward driving. In the experiments, two voltages with different amplitudes are applied on the two transducers, respectively: the one with higher voltage serves as the actuator, whereas the other one applied with lower voltage is used to reduce the frictional force. The prototype achieves maximum no-load speed and thrust force of 244 mm/s and 9.8 N. This work gives a new idea for the construction of standing wave piezoelectric ultrasonic actuator with bi-directional driving ability. Copyright © 2017 Elsevier B.V. All rights reserved.

Parent and teen agreement on driving expectations prior to teen licensure.

PubMed

Hamann, Cara J; Ramirez, Marizen; Yang, Jingzhen; Chande, Vidya; Peek-Asa, Corinne

2014-01-01

To examine pre-licensure agreement on driving expectations and predictors of teen driving expectations among parent-teen dyads. Cross-sectional survey of 163 parent-teen dyads. Descriptive statistics, weighted Kappa coefficients, and linear regression were used to examine expectations about post-licensure teen driving. Teens reported high pre-licensure unsupervised driving (N = 79, 48.5%) and regular access to a car (N = 130, 81.8%). Parents and teens had low agreement on teen driving expectations (eg, after dark, κw = 0.23). Each time teens currently drove to/from school, their expectation of driving in risky conditions post-licensure increased (β = 0.21, p = .02). Pre-licensure improvement of parent-teen agreement on driving expectations are needed to have the greatest impact on preventing teens from driving in high risk conditions.

A beam position monitor for the diagnostic line in MEBT2 of J-PARC linac

NASA Astrophysics Data System (ADS)

Miura, A.; Tamura, J.; Kawane, Y.

2017-07-01

In the linac of the Japan Proton Accelerator Research Complex (J-PARC), the neutral hydrogen (H0) beam from the negative hydrogen ion (H-) beam is one of key issues in mitigating beam losses. To diagnose H0 particles, we installed a set of beam-bump magnets to generate a chicane orbit of the H- beam. The beam position monitors (BPMs) in the beam line are used for orbit correction to maintain the beam displacement within 2.0 mm from the duct center. To measure the beam displacement under different drive currents of the beam-bump magnets, a new wide-range BPM was designed and manufactured to evaluate the horizontal beam position by using a correction function to compensate for non-linearity. We also employed the beam profile monitor (WSM: wire scanner monitor) to measure the H- beam profile, which helped us to compare the beam position measurements. In this paper, the design and the performance of the wide-range BPM are described. In addition, we present a comparison of the beam position measured by the BPM and the WSM.

The relationship between personalities and self-report positive driving behavior in a Chinese sample

PubMed Central

Sun, Xianghong; Zhang, Kan

2018-01-01

Driving behaviors play an important role in accident involvement. Concretely speaking, aberrant driving behaviors would cause more accidents, and oppositely positive driving behaviors would promote to build safety traffic environment. The main goals of this study were to explore the positive driving behavior and its relationship with personality in a Chinese sample. A total of 421 licensed drivers (286 male and 135 female) from Beijing, China completed the Positive Driver Behavior Scale (PDBS), the Driver Behavior Questionnaire (DBQ), the Dula Dangerous Driving Index (DDDI) and the Big Five Inventory (BFI) on a voluntary and anonymous basis. The results showed that the Chinese version of the PDBS has both reliability and validity and that the PDBS was significantly correlated with the BFI. Specifically, the PDBS was negatively correlated with neuroticism (r = -0.38) and positively correlated with extraversion, agreeableness, conscientiousness and openness to experience (the correlation coefficient ranged from 0.36 to 0.55). In contrast with previous research, age was negatively correlated with the PDBS (r = -0.38) in our sample, which may have resulted from less driving experience or a lack of available cognitive resources. PMID:29324823

The relationship between personalities and self-report positive driving behavior in a Chinese sample.

PubMed

Shen, Biying; Qu, Weina; Ge, Yan; Sun, Xianghong; Zhang, Kan

2018-01-01

Driving behaviors play an important role in accident involvement. Concretely speaking, aberrant driving behaviors would cause more accidents, and oppositely positive driving behaviors would promote to build safety traffic environment. The main goals of this study were to explore the positive driving behavior and its relationship with personality in a Chinese sample. A total of 421 licensed drivers (286 male and 135 female) from Beijing, China completed the Positive Driver Behavior Scale (PDBS), the Driver Behavior Questionnaire (DBQ), the Dula Dangerous Driving Index (DDDI) and the Big Five Inventory (BFI) on a voluntary and anonymous basis. The results showed that the Chinese version of the PDBS has both reliability and validity and that the PDBS was significantly correlated with the BFI. Specifically, the PDBS was negatively correlated with neuroticism (r = -0.38) and positively correlated with extraversion, agreeableness, conscientiousness and openness to experience (the correlation coefficient ranged from 0.36 to 0.55). In contrast with previous research, age was negatively correlated with the PDBS (r = -0.38) in our sample, which may have resulted from less driving experience or a lack of available cognitive resources.

Upflow bioreactor having a septum and an auger and drive assembly

DOEpatents

Hansen, Carl S.; Hansen, Conly L.

2007-11-06

An upflow bioreactor includes a vessel having an inlet and an outlet configured for upflow operation. A septum is positioned within the vessel and defines a lower chamber and an upper chamber. The septum includes an aperture that provides fluid communication between the upper chamber and lower chamber. The bioreactor also includes an auger positioned in the aperture of the septum. The vessel includes an opening in the top for receiving the auger. The auger extends from a drive housing, which is position over the opening and provides a seal around the opening. The drive housing is adjustable relative to the vessel. The position of the auger in the aperture can be adjusted by adjusting the drive housing relative to the vessel. The auger adjustment mechanism allows the auger to be accurately positioned within the aperture. The drive housing can also include a fluid to provide an additional seal around the shaft of the auger.

Attenuation of cryocooler induced vibration using multimodal tuned dynamic absorbers

NASA Astrophysics Data System (ADS)

Veprik, Alexander; Babitsky, Vladimir; Tuito, Avi

2017-05-01

Modern infrared imagers often rely on split Stirling linear cryocoolers comprising compressor and expander, the relative position of which is governed by the optical design and packaging constraints. A force couple generated by imbalanced reciprocation of moving components inside both compressor and expander result in cryocooler induced vibration comprising angular and translational tonal components manifesting itself in the form of line of sight jitter and dynamic defocusing. Since linear cryocooler is usually driven at a fixed and precisely adjustable frequency, a tuned dynamic absorber is a well suited tool for vibration control. It is traditionally made in the form of lightweight single degree of freedom undamped mechanical resonator, the frequency of which is essentially matched with the driving frequency or vice versa. Unfortunately, the performance of such a traditional approach is limited in terms of simultaneous attenuating translational and angular components of cooler induced vibration. The authors are enhancing the traditional concept and consider multimodal tuned dynamic absorber made in the form of weakly damped mechanical resonator, where the frequencies of useful dynamic modes are essentially matched with the driving frequency. Dynamic analysis and experimental testing show that the dynamic reactions (forces and moments) produced by such a device may simultaneously attenuate both translational and angular components of cryocoolerinduced vibration. The authors are considering different embodiments and their suitability for different packaging concepts. The outcomes of theoretical predictions are supported by full scale experimentation.

Stable Spheromaks with Profile Control

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

Fowler, T K; Jayakumar, R

A spheromak equilibrium with zero edge current is shown to be stable to both ideal MHD and tearing modes that normally produce Taylor relaxation in gun-injected spheromaks. This stable equilibrium differs from the stable Taylor state in that the current density j falls to zero at the wall. Estimates indicate that this current profile could be sustained by non-inductive current drive at acceptable power levels. Stability is determined using the NIMROD code for linear stability analysis. Non-linear NIMROD calculations with non-inductive current drive could point the way to improved fusion reactors.

Device with Functions of Linear Motor and Non-contact Power Collector for Wireless Drive

NASA Astrophysics Data System (ADS)

Fujii, Nobuo; Mizuma, Tsuyoshi

The authors propose a new apparatus with functions of propulsion and non-contact power collection for a future vehicle which can run like an electric vehicle supplied from the onboard battery source in most of the root except near stations. The batteries or power-capacitors are non-contact charged from the winding connected with commercial power on ground in the stations etc. The apparatus has both functions of linear motor and transformer, and the basic configuration is a wound-secondary type linear induction motor (LIM). In the paper, the wound type LIM with the concentrated single-phase winding for the primary member on the ground is dealt from the viewpoint of low cost arrangement. The secondary winding is changed to the single-phase connection for zero thrust in the transformer operation, and the two-phase connection for the linear motor respectively. The change of connection is done by the special converter for charge and linear drive on board. The characteristics are studied analytically.

Metal band drives in spacecraft mechanisms

NASA Technical Reports Server (NTRS)

Maus, Daryl

1993-01-01

Transmitting and changing the characteristics of force and stroke is a requirement in nearly all mechanisms. Examples include changing linear to rotary motion, providing a 90 deg change in direction, and amplifying stroke or force. Requirements for size, weight, efficiency and reliability create unique problems in spacecraft mechanisms. Flexible metal band and cam drive systems provide powerful solutions to these problems. Band drives, rack and pinion gears, and bell cranks are compared for effectiveness. Band drive issues are discussed including materials, bend radius, fabrication, attachment and reliability. Numerous mechanisms are shown which illustrate practical applications of band drives.

Position measurement of the direct drive motor of Large Aperture Telescope

NASA Astrophysics Data System (ADS)

Li, Ying; Wang, Daxing

2010-07-01

Along with the development of space and astronomy science, production of large aperture telescope and super large aperture telescope will definitely become the trend. It's one of methods to solve precise drive of large aperture telescope using direct drive technology unified designed of electricity and magnetism structure. A direct drive precise rotary table with diameter of 2.5 meters researched and produced by us is a typical mechanical & electrical integration design. This paper mainly introduces position measurement control system of direct drive motor. In design of this motor, position measurement control system requires having high resolution, and precisely aligning the position of rotor shaft and making measurement, meanwhile transferring position information to position reversing information corresponding to needed motor pole number. This system has chosen high precision metal band coder and absolute type coder, processing information of coders, and has sent 32-bit RISC CPU making software processing, and gained high resolution composite coder. The paper gives relevant laboratory test results at the end, indicating the position measurement can apply to large aperture telescope control system. This project is subsidized by Chinese National Natural Science Funds (10833004).

Linear magnetic motor/generator. [to generate electric energy using magnetic flux for spacecraft power supply

NASA Technical Reports Server (NTRS)

Studer, P. A. (Inventor)

1982-01-01

A linear magnetic motor/generator is disclosed which uses magnetic flux to provide mechanical motion or electrical energy. The linear magnetic motor/generator includes an axially movable actuator mechanism. A permament magnet mechanism defines a first magnetic flux path which passes through a first end portion of the actuator mechanism. Another permament magnet mechanism defines a second magnetic flux path which passes through a second end portion of the actuator mechanism. A drive coil defines a third magnetic flux path passing through a third central portion of the actuator mechanism. A drive coil selectively adds magnetic flux to and subtracts magnetic flux from magnetic flux flowing in the first and second magnetic flux path.

The influence of continuous historical velocity difference information on micro-cooperative driving stability

NASA Astrophysics Data System (ADS)

Yang, Liang-Yi; Sun, Di-Hua; Zhao, Min; Cheng, Sen-Lin; Zhang, Geng; Liu, Hui

2018-03-01

In this paper, a new micro-cooperative driving car-following model is proposed to investigate the effect of continuous historical velocity difference information on traffic stability. The linear stability criterion of the new model is derived with linear stability theory and the results show that the unstable region in the headway-sensitivity space will be shrunk by taking the continuous historical velocity difference information into account. Through nonlinear analysis, the mKdV equation is derived to describe the traffic evolution behavior of the new model near the critical point. Via numerical simulations, the theoretical analysis results are verified and the results indicate that the continuous historical velocity difference information can enhance the stability of traffic flow in the micro-cooperative driving process.

Comparison of Classifiers for Decoding Sensory and Cognitive Information from Prefrontal Neuronal Populations

PubMed Central

Astrand, Elaine; Enel, Pierre; Ibos, Guilhem; Dominey, Peter Ford; Baraduc, Pierre; Ben Hamed, Suliann

2014-01-01

Decoding neuronal information is important in neuroscience, both as a basic means to understand how neuronal activity is related to cerebral function and as a processing stage in driving neuroprosthetic effectors. Here, we compare the readout performance of six commonly used classifiers at decoding two different variables encoded by the spiking activity of the non-human primate frontal eye fields (FEF): the spatial position of a visual cue, and the instructed orientation of the animal's attention. While the first variable is exogenously driven by the environment, the second variable corresponds to the interpretation of the instruction conveyed by the cue; it is endogenously driven and corresponds to the output of internal cognitive operations performed on the visual attributes of the cue. These two variables were decoded using either a regularized optimal linear estimator in its explicit formulation, an optimal linear artificial neural network estimator, a non-linear artificial neural network estimator, a non-linear naïve Bayesian estimator, a non-linear Reservoir recurrent network classifier or a non-linear Support Vector Machine classifier. Our results suggest that endogenous information such as the orientation of attention can be decoded from the FEF with the same accuracy as exogenous visual information. All classifiers did not behave equally in the face of population size and heterogeneity, the available training and testing trials, the subject's behavior and the temporal structure of the variable of interest. In most situations, the regularized optimal linear estimator and the non-linear Support Vector Machine classifiers outperformed the other tested decoders. PMID:24466019

Technology evaluation of man-rated acceleration test equipment for vestibular research

NASA Technical Reports Server (NTRS)

Taback, I.; Kenimer, R. L.; Butterfield, A. J.

1983-01-01

The considerations for eliminating acceleration noise cues in horizontal, linear, cyclic-motion sleds intended for both ground and shuttle-flight applications are addressed. the principal concerns are the acceleration transients associated with change in direction-of-motion for the carriage. The study presents a design limit for acceleration cues or transients based upon published measurements for thresholds of human perception to linear cyclic motion. The sources and levels for motion transients are presented based upon measurements obtained from existing sled systems. The approaches to a noise-free system recommends the use of air bearings for the carriage support and moving-coil linear induction motors operating at low frequency as the drive system. Metal belts running on air bearing pulleys provide an alternate approach to the driving system. The appendix presents a discussion of alternate testing techniques intended to provide preliminary type data by means of pendulums, linear motion devices and commercial air bearing tables.

Value and limitations of transpulmonary pressure calculations during intra-abdominal hypertension.

PubMed

Cortes-Puentes, Gustavo A; Gard, Kenneth E; Adams, Alexander B; Faltesek, Katherine A; Anderson, Christopher P; Dries, David J; Marini, John J

2013-08-01

To clarify the effect of progressively increasing intra-abdominal pressure on esophageal pressure, transpulmonary pressure, and functional residual capacity. Controlled application of increased intra-abdominal pressure at two positive end-expiratory pressure levels (1 and 10 cm H2O) in an anesthetized porcine model of controlled ventilation. Large animal laboratory of a university-affiliated hospital. Eleven deeply anesthetized swine (weight 46.2 ± 6.2 kg). Air-regulated intra-abdominal hypertension (0-25 mm Hg). Esophageal pressure, tidal compliance, bladder pressure, and end-expiratory lung aeration by gas dilution. Functional residual capacity was significantly reduced by increasing intra-abdominal pressure at both positive end-expiratory pressure levels (p ≤ 0.0001) without corresponding changes of end-expiratory esophageal pressure. Above intra-abdominal pressure 5 mm Hg, plateau airway pressure increased linearly by ~ 50% of the applied intra-abdominal pressure value, associated with commensurate changes of esophageal pressure. With tidal volume held constant, negligible changes occurred in transpulmonary pressure due to intra-abdominal pressure. Driving pressures calculated from airway pressures alone (plateau airway pressure--positive end-expiratory pressure) did not equate to those computed from transpulmonary pressure (tidal changes in transpulmonary pressure). Increasing positive end-expiratory pressure shifted the predominantly negative end-expiratory transpulmonary pressure at positive end-expiratory pressure 1 cm H2O (mean -3.5 ± 0.4 cm H2O) into the positive range at positive end-expiratory pressure 10 cm H2O (mean 0.58 ± 1.2 cm H2O). Despite its insensitivity to changes in functional residual capacity, measuring transpulmonary pressure may be helpful in explaining how different levels of positive end-expiratory pressure influence recruitment and collapse during tidal ventilation in the presence of increased intra-abdominal pressure and in calculating true transpulmonary driving pressure (tidal changes of transpulmonary pressure). Traditional interpretations of respiratory mechanics based on unmodified airway pressure were misleading regarding lung behavior in this setting.

Inductive Non-Contact Position Sensor

NASA Technical Reports Server (NTRS)

Youngquist, Robert; Garcia, Alyssa; Simmons, Stephen

2010-01-01

Optical hardware has been developed to measure the depth of defects in the Space Shuttle Orbiter's windows. In this hardware, a mirror is translated such that its position corresponds to the defect's depth, so the depth measurement problem is transferred to a mirror-position measurement problem. This is preferable because the mirror is internal to the optical system and thus accessible. Based on requirements supplied by the window inspectors, the depth of the defects needs to be measured over a range of 200 microns with a resolution of about 100 nm and an accuracy of about 400 nm. These same requirements then apply to measuring the position of the mirror, and in addition, since this is a scanning system, a response time of about 10 ms is needed. A market search was conducted and no sensor that met these requirements that also fit into the available housing volume (less than one cubic inch) was found, so a novel sensor configuration was constructed to meet the requirements. This new sensor generates a nearly linearly varying magnetic field over a small region of space, which can easily be sampled, resulting in a voltage proportional to position. Experiments were done with a range of inductor values, drive voltages, drive frequencies, and inductor shapes. A rough mathematical model was developed for the device that, in most aspects, describes how it operates and what electrical parameters should be chosen for best performance. The final configuration met all the requirements, yielding a small rugged sensor that was easy to use and had nanometer resolution over more than the 200-micron range required. The inductive position sensor is a compact device (potentially as small as 2 cubic centimeters), which offers nanometer-position resolution over a demonstrated range of nearly 1 mm. One of its advantages is the simplicity of its electrical design. Also, the sensor resolution is nearly uniform across its operational range, which is in contrast to eddy current and capacitive sensors whose sensitivity is dependent upon position.

Electromagnetic driving units for complex microrobotic systems

NASA Astrophysics Data System (ADS)

Michel, Frank; Ehrfeld, Wolfgang; Berg, Udo; Degen, Reinhard; Schmitz, Felix

1998-10-01

Electromagnetic actuators play an important role in macroscopic robotic systems. In combination with motion transformers, like reducing gear units, angular gears or spindle-screw drives, electromagnetic motors in large product lines ensure the rotational or linear motion of robot driving units and grippers while electromagnets drive valves or part conveyors. In this paper micro actuators and miniaturized motion transformers are introduced which allow a similar development in microrobotics. An electromagnetic motor and a planetary gear box, both with a diameter of 1.9 mm, are already commercially available from the cooperation partner of IMM, the company Dr. Fritz Faulhaber GmbH in Schonaich, Germany. In addition, a motor with a diameter of 2.4 mm is in development. The motors successfully drive an angular gear and a belt drive. A linear stage with a motion range of 7 mm and an overall size as small as 5 X 3.5 X 24 mm3 has been realized involving the motor, a stationary spur gear with zero backlash and a spindle-screw drive. By the use of these commercially available elements complex microrobots can be built up cost-efficiently and rapidly. Furthermore, a batch process has been developed to produce the coils of micro actuator arrays using lithographic techniques with SU-8 resin. In applying these components, the modular construction of complex microrobotic systems becomes feasible.

Excursions out-of-lane versus standard deviation of lateral position as outcome measure of the on-the-road driving test.

PubMed

Verster, Joris C; Roth, Thomas

2014-07-01

The traditional outcome measure of the Dutch on-the-road driving test is the standard deviation of lateral position (SDLP), the weaving of the car. This paper explores whether excursions out-of-lane are a suitable additional outcome measure to index driving impairment. A literature search was conducted to search for driving tests that used both SDLP and excursions out-of-lane as outcome measures. The analyses were limited to studies examining hypnotic drugs because several of these drugs have been shown to produce next-morning sedation. Standard deviation of lateral position was more sensitive in demonstrating driving impairment. In fact, solely relying on excursions out-of-lane as outcome measure incorrectly classifies approximately half of impaired drives as unimpaired. The frequency of excursions out-of-lane is determined by the mean lateral position within the right traffic lane. Defining driving impairment as having a ΔSDLP > 2.4 cm, half of the impaired driving tests (51.2%, 43/84) failed to produce excursions out-of-lane. Alternatively, 20.9% of driving tests with ΔSDLP < 2.4 cm (27/129) had at least one excursion out-of-lane. Excursions out-of-lane are neither a suitable measure to demonstrate driving impairment nor is this measure sufficiently sensitive to differentiate adequately between differences in magnitude of driving impairment. Copyright © 2014 John Wiley & Sons, Ltd.

Multiple-degree-of-freedom vehicle

DOEpatents

Borenstein, Johann

1995-01-01

A multi-degree-of-freedom vehicle employs a compliant linkage to accommodate the need for a variation in the distance between drive wheels or drive systems which are independently steerable and drivable. The subject vehicle is provided with rotary encodes to provide signals representative of the orientation of the steering pivot associated with each such drive wheel or system, and a linear encoder which issues a signal representative of the fluctuations in the distance between the drive elements. The wheels of the vehicle are steered and driven in response to the linear encoder signal, there being provided a controller system for minimizing the fluctuations in the distance. The controller system is a software implementation of a plurality of controllers, operating at the chassis level and at the vehicle level. A trajectory interpolator receives x-displacement, y-displacement, and .theta.-displacement signals and produces to the vehicle level controller trajectory signals corresponding to interpolated control signals. The x-displacement, y-displacement, and .theta.-displacement signals are received from a human operator, via a manipulable joy stick.

Noise fluctuations and drive dependence of the skyrmion Hall effect in disordered systems

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

Reichhardt, Charles; Olson Reichhardt, Cynthia Jane

Using a particle-based simulation model, we show that quenched disorder creates a drive-dependent skyrmion Hall effect as measured by the change in the ratiomore » $$R={V}_{\\perp }/{V}_{| | }$$ of the skyrmion velocity perpendicular (V ⊥) and parallel ($${V}_{| | }$$) to an external drive. R is zero at depinning and increases linearly with increasing drive, in agreement with recent experimental observations. At sufficiently high drives where the skyrmions enter a free flow regime, R saturates to the disorder-free limit. In addition, this behavior is robust for a wide range of disorder strengths and intrinsic Hall angle values, and occurs whenever plastic flow is present. For systems with small intrinsic Hall angles, we find that the Hall angle increases linearly with external drive, as also observed in experiment. In the weak pinning regime where the skyrmion lattice depins elastically, R is nonlinear and the net direction of the skyrmion lattice motion can rotate as a function of external drive. We show that the changes in the skyrmion Hall effect correlate with changes in the power spectrum of the skyrmion velocity noise fluctuations. The plastic flow regime is associated with $1/f$ noise, while in the regime in which R has saturated, the noise is white with a weak narrow band signal, and the noise power drops by several orders of magnitude. Finally, at low drives, the velocity noise in the perpendicular and parallel directions is of the same order of magnitude, while at intermediate drives the perpendicular noise fluctuations are much larger.« less

Noise fluctuations and drive dependence of the skyrmion Hall effect in disordered systems

DOE PAGES

Reichhardt, Charles; Olson Reichhardt, Cynthia Jane

2016-09-29

Using a particle-based simulation model, we show that quenched disorder creates a drive-dependent skyrmion Hall effect as measured by the change in the ratiomore » $$R={V}_{\\perp }/{V}_{| | }$$ of the skyrmion velocity perpendicular (V ⊥) and parallel ($${V}_{| | }$$) to an external drive. R is zero at depinning and increases linearly with increasing drive, in agreement with recent experimental observations. At sufficiently high drives where the skyrmions enter a free flow regime, R saturates to the disorder-free limit. In addition, this behavior is robust for a wide range of disorder strengths and intrinsic Hall angle values, and occurs whenever plastic flow is present. For systems with small intrinsic Hall angles, we find that the Hall angle increases linearly with external drive, as also observed in experiment. In the weak pinning regime where the skyrmion lattice depins elastically, R is nonlinear and the net direction of the skyrmion lattice motion can rotate as a function of external drive. We show that the changes in the skyrmion Hall effect correlate with changes in the power spectrum of the skyrmion velocity noise fluctuations. The plastic flow regime is associated with $1/f$ noise, while in the regime in which R has saturated, the noise is white with a weak narrow band signal, and the noise power drops by several orders of magnitude. Finally, at low drives, the velocity noise in the perpendicular and parallel directions is of the same order of magnitude, while at intermediate drives the perpendicular noise fluctuations are much larger.« less

Design and modeling of magnetically driven electric-field sensor for non-contact DC voltage measurement in electric power systems.

PubMed

Wang, Decai; Li, Ping; Wen, Yumei

2016-10-01

In this paper, the design and modeling of a magnetically driven electric-field sensor for non-contact DC voltage measurement are presented. The magnetic drive structure of the sensor is composed of a small solenoid and a cantilever beam with a cylindrical magnet mounted on it. The interaction of the magnet and the solenoid provides the magnetic driving force for the sensor. Employing magnetic drive structure brings the benefits of low driving voltage and large vibrating displacement, which consequently results in less interference from the drive signal. In the theoretical analyses, the capacitance calculation model between the wire and the sensing electrode is built. The expression of the magnetic driving force is derived by the method of linear fitting. The dynamical model of the magnetic-driven cantilever beam actuator is built by using Euler-Bernoulli theory and distributed parameter method. Taking advantage of the theoretical model, the output voltage of proposed sensor can be predicted. The experimental results are in good agreement with the theoretical results. The proposed sensor shows a favorable linear response characteristic. The proposed sensor has a measuring sensitivity of 9.87 μV/(V/m) at an excitation current of 37.5 mA. The electric field intensity resolution can reach 10.13 V/m.

Modeling and Positioning of a PZT Precision Drive System.

PubMed

Liu, Che; Guo, Yanling

2017-11-08

The fact that piezoelectric ceramic transducer (PZT) precision drive systems in 3D printing are faced with nonlinear problems with respect to positioning, such as hysteresis and creep, has had an extremely negative impact on the precision of laser focusing systems. To eliminate the impact of PZT nonlinearity during precision drive movement, mathematical modeling and theoretical analyses of each module comprising the system were carried out in this study, a micro-displacement measurement circuit based on Position Sensitive Detector (PSD) is constructed, followed by the establishment of system closed-loop control and creep control models. An XL-80 laser interferometer (Renishaw, Wotton-under-Edge, UK) was used to measure the performance of the precision drive system, showing that system modeling and control algorithms were correct, with the requirements for precision positioning of the drive system satisfied.

Two-dimensional Inductive Position Sensing System

NASA Technical Reports Server (NTRS)

Youngquist, Robert C. (Inventor); Starr, Stanley O. (Inventor)

2015-01-01

A two-dimensional inductive position sensing system uses four drive inductors arranged at the vertices of a parallelogram and a sensing inductor positioned within the parallelogram. The sensing inductor is movable within the parallelogram and relative to the drive inductors. A first oscillating current at a first frequency is supplied to a first pair of the drive inductors located at ends of a first diagonal of the parallelogram. A second oscillating current at a second frequency is supplied to a second pair of the drive inductors located at ends of a second diagonal of the parallelogram. As a result, the sensing inductor generates a first output voltage at the first frequency and a second output voltage at the second frequency. A processor determines a position of the sensing inductor relative to the drive inductors using the first output voltage and the second output voltage.

Modeling and Positioning of a PZT Precision Drive System

PubMed Central

Liu, Che; Guo, Yanling

2017-01-01

The fact that piezoelectric ceramic transducer (PZT) precision drive systems in 3D printing are faced with nonlinear problems with respect to positioning, such as hysteresis and creep, has had an extremely negative impact on the precision of laser focusing systems. To eliminate the impact of PZT nonlinearity during precision drive movement, mathematical modeling and theoretical analyses of each module comprising the system were carried out in this study, a micro-displacement measurement circuit based on Position Sensitive Detector (PSD) is constructed, followed by the establishment of system closed-loop control and creep control models. An XL-80 laser interferometer (Renishaw, Wotton-under-Edge, UK) was used to measure the performance of the precision drive system, showing that system modeling and control algorithms were correct, with the requirements for precision positioning of the drive system satisfied. PMID:29117140

Ego, drives, and the dynamics of internal objects

PubMed Central

Boag, Simon

2014-01-01

This paper addresses the relationship between the ego, id, and internal objects. While ego psychology views the ego as autonomous of the drives, a less well-known alternative position views the ego as constituted by the drives. Based on Freud’s ego-instinct account, this position has developed into a school of thought which postulates that the drives act as knowers. Given that there are multiple drives, this position proposes that personality is constituted by multiple knowers. Following on from Freud, the ego is viewed as a composite sub-set of the instinctual drives (ego-drives), whereas those drives cut off from expression form the id. The nature of the “self” is developed in terms of identification and the possibility of multiple personalities is also established. This account is then extended to object-relations and the explanatory value of the ego-drive account is discussed in terms of the addressing the nature of ego-structures and the dynamic nature of internal objects. Finally, the impact of psychological conflict and the significance of repression for understanding the nature of splits within the psyche are also discussed. PMID:25071640

Integrated Optoelectronic Position Sensor for Scanning Micromirrors

PubMed Central

Cheng, Xiang; Sun, Xinglin; Liu, Yan; Zhu, Lijun; Zhang, Xiaoyang; Zhou, Liang

2018-01-01

Scanning micromirrors have been used in a wide range of areas, but many of them do not have position sensing built in, which significantly limits their application space. This paper reports an integrated optoelectronic position sensor (iOE-PS) that can measure the linear displacement and tilting angle of electrothermal MEMS (Micro-electromechanical Systems) scanning mirrors. The iOE-PS integrates a laser diode and its driving circuits, a quadrant photo-detector (QPD) and its readout circuits, and a band-gap reference all on a single chip, and it has been fabricated in a standard 0.5 μm CMOS (Complementary Metal Oxide Semiconductor) process. The footprint of the iOE-PS chip is 5 mm × 5 mm. Each quadrant of the QPD has a photosensitive area of 500 µm × 500 µm and the spacing between adjacent quadrants is 500 μm. The iOE-PS chip is simply packaged underneath of an electrothermally-actuated MEMS mirror. Experimental results show that the iOE-PS has a linear response when the MEMS mirror plate moves vertically between 2.0 mm and 3.0 mm over the iOE-PS chip or scans from −5 to +5°. Such MEMS scanning mirrors integrated with the iOE-PS can greatly reduce the complexity and cost of the MEMS mirrors-enabled modules and systems. PMID:29587451

A piezoelectric ultrasonic linear micromotor using a slotted stator.

PubMed

Yun, Cheol-Ho; Watson, Brett; Friend, James; Yeo, Leslie

2010-08-01

A novel ultrasonic micro linear motor that uses 1st longitudinal and 2nd bending modes, derived from a bartype stator with a rectangular slot cut through the stator length, has been proposed and designed for end-effect devices of microrobotics and bio-medical applications. The slot structure plays an important role in the motor design, and can be used not only to tune the resonance frequency of the two vibration modes but also to reduce the undesirable longitudinal coupling displacement caused by bending vibration at the end of the stator. By using finite element analysis, the optimal slot dimension to improve the driving tip motion was determined, resulting in the improvement of the motor performance. The trial linear motor, with a weight of 1.6 g, gave a maximum driving velocity of 1.12 m/s and a maximum driving force of 3.4 N. A maximum mechanical output power of 1.1 W was obtained at force of 1.63 N and velocity of 0.68 m/s. The output mechanical power per unit weight was 688 W/kg.

Proposed low-temperature solar engine

NASA Technical Reports Server (NTRS)

Peoples, J. A.; Kearns, G. B.

1976-01-01

Engine, proposed for conversion of Sun's heat to motion without need for heat pumps and associated equipment, uses expansion and contraction of aluminum rod to drive tow out-of-phase windlasses. Linear displacement of 0.076 cm in rod will exert sufficient force to drive pumps, generators, and compressors.

Analysis and correction of linear optics errors, and operational improvements in the Indus-2 storage ring

NASA Astrophysics Data System (ADS)

Husain, Riyasat; Ghodke, A. D.

2017-08-01

Estimation and correction of the optics errors in an operational storage ring is always vital to achieve the design performance. To achieve this task, the most suitable and widely used technique, called linear optics from closed orbit (LOCO) is used in almost all storage ring based synchrotron radiation sources. In this technique, based on the response matrix fit, errors in the quadrupole strengths, beam position monitor (BPM) gains, orbit corrector calibration factors etc. can be obtained. For correction of the optics, suitable changes in the quadrupole strengths can be applied through the driving currents of the quadrupole power supplies to achieve the desired optics. The LOCO code has been used at the Indus-2 storage ring for the first time. The estimation of linear beam optics errors and their correction to minimize the distortion of linear beam dynamical parameters by using the installed number of quadrupole power supplies is discussed. After the optics correction, the performance of the storage ring is improved in terms of better beam injection/accumulation, reduced beam loss during energy ramping, and improvement in beam lifetime. It is also useful in controlling the leakage in the orbit bump required for machine studies or for commissioning of new beamlines.

Driving anger and its relationships with type A behavior patterns and trait anger: Differences between professional and non-professional drivers

PubMed Central

Feng, Zhongxiang; Yang, Miaomiao; Ma, Changxi; Jiang, Kang; Lei, Yewei; Huang, Wenjuan; Huang, Zhipeng; Zhan, Jingjing; Zhou, Muxiong

2017-01-01

The present study examined the types of situations that caused Chinese professional and non-professional drivers to become angry and investigated the differences in driving-elicited anger, considering the influences of type A behavior pattern and trait anger between the two groups. The 20-item revised Driving Anger Scale (DAS) was used to assess a sample of 232 drivers (57% professional, 43% non-professional). The non-professional drivers reported significantly higher levels of anger than the professional drivers on the overall Driving Anger Scale (DAS) and the traffic obstructions and discourtesy subscales. In both groups, the preferred driving speeds were positively related to driving anger. Furthermore, drivers with a type A personality exhibited higher overall driving anger scores and higher anger scores in response to traffic obstructions and slow driving than drivers with a type B personality. Trait anger was significantly related to driving anger in both groups. In the non-professional group, type A behavior patterns (TABPs) and time hurry (TH) were positively correlated with anger evoked by slow driving. In the professional group, TABPs, TH and competitive hostility (CH) were positively related to driving anger, and the TABPs exerted an indirect effect on driving anger by mediating the influence of trait anger. Overall, these findings provide a theoretical basis for implementing targeted interventions for driving anger in both professional and non-professional drivers. PMID:29253004

Integrated Fault Diagnosis Algorithm for Motor Sensors of In-Wheel Independent Drive Electric Vehicles

PubMed Central

Jeon, Namju; Lee, Hyeongcheol

2016-01-01

An integrated fault-diagnosis algorithm for a motor sensor of in-wheel independent drive electric vehicles is presented. This paper proposes a method that integrates the high- and low-level fault diagnoses to improve the robustness and performance of the system. For the high-level fault diagnosis of vehicle dynamics, a planar two-track non-linear model is first selected, and the longitudinal and lateral forces are calculated. To ensure redundancy of the system, correlation between the sensor and residual in the vehicle dynamics is analyzed to detect and separate the fault of the drive motor system of each wheel. To diagnose the motor system for low-level faults, the state equation of an interior permanent magnet synchronous motor is developed, and a parity equation is used to diagnose the fault of the electric current and position sensors. The validity of the high-level fault-diagnosis algorithm is verified using Carsim and Matlab/Simulink co-simulation. The low-level fault diagnosis is verified through Matlab/Simulink simulation and experiments. Finally, according to the residuals of the high- and low-level fault diagnoses, fault-detection flags are defined. On the basis of this information, an integrated fault-diagnosis strategy is proposed. PMID:27973431

Modeling the influence of Chevron alignment sign on young male driver performance: A driving simulator study.

PubMed

Wu, Yiping; Zhao, Xiaohua; Chen, Chen; He, Jiayuan; Rong, Jian; Ma, Jianming

2016-10-01

In China, the Chevron alignment sign on highways is a vertical rectangle with a white arrow and border on a blue background, which differs from its counterpart in other countries. Moreover, little research has been devoted to the effectiveness of China's Chevron signs; there is still no practical method to quantitatively describe the impact of Chevron signs on driver performance in roadway curves. In this paper, a driving simulator experiment collected data on the driving performance of 30 young male drivers as they navigated on 29 different horizontal curves under different conditions (presence of Chevron signs, curve radius and curve direction). To address the heterogeneity issue in the data, three models were estimated and tested: a pooled data linear regression model, a fixed effects model, and a random effects model. According to the Hausman Test and Akaike Information Criterion (AIC), the random effects model offers the best fit. The current study explores the relationship between driver performance (i.e., vehicle speed and lane position) and horizontal curves with respect to the horizontal curvature, presence of Chevron signs, and curve direction. This study lays a foundation for developing procedures and guidelines that would allow more uniform and efficient deployment of Chevron signs on China's highways. Copyright © 2016 Elsevier Ltd. All rights reserved.

Rotational MEMS mirror with latching arm for silicon photonics

NASA Astrophysics Data System (ADS)

Brière, Jonathan; Beaulieu, Philippe-Olivier; Saidani, Menouer; Nabki, Frederic; Menard, Michaël.

2015-02-01

We present an innovative rotational MEMS mirror that can control the direction of propagation of light beams inside of planar waveguides implemented in silicon photonics. Potential applications include but are not limited to optical telecommunications, medical imaging, scan and spectrometry. The mirror has a half-cylinder shape with a radius of 300 μm that provides low and constant optical losses over the full angular displacement range. A circular comb drive structure is anchored such that it allows free or latched rotation experimentally demonstrated over 8.5° (X-Y planar rotational movement) using 290V electrostatic actuation. The entire MEMS structure was implemented using the MEMSCAP SOIMUMPs process. The center of the anchor beam is designed to be the approximate rotation point of the circular comb drive to counter the rotation offset of the mirror displacement. A mechanical characterization of the MEMS mirror is presented. The latching mechanism provides up to 20 different angular locking positions allowing the mirror to counter any resonance or vibration effects and it is actuated with an electrostatic linear comb drive. An innovative gap closing structure was designed to reduce optical propagation losses due to beam divergence in the interstitial space between the mirror and the planar waveguide. The gap closing structure is also electrostatically actuated and includes two side stoppers to prevent stiction.

Spacecraft-borne long life cryogenic refrigeration: Status and trends

NASA Technical Reports Server (NTRS)

Johnson, A. L.

1983-01-01

The status of cryogenic refrigerator development intended for, or possibly applicable to, long life spacecraft-borne application is reviewed. Based on these efforts, the general development trends are identified. Using currently projected technology needs, the various trends are compared and evaluated. The linear drive, non-contacting bearing Stirling cycle refrigerator concept appears to be the best current approach that will meet the technology projection requirements for spacecraft-borne cryogenic refrigerators. However, a multiply redundant set of lightweight, moderate life, moderate reliability Stirling cycle cryogenic refrigerators using high-speed linear drive and sliding contact bearings may possibly suffice.

Balancing Vibrations at Harmonic Frequencies by Injecting Harmonic Balancing Signals into the Armature of a Linear Motor/Alternator Coupled to a Stirling Machine

NASA Technical Reports Server (NTRS)

Holliday, Ezekiel S. (Inventor)

2014-01-01

Vibrations at harmonic frequencies are reduced by injecting harmonic balancing signals into the armature of a linear motor/alternator coupled to a Stirling machine. The vibrations are sensed to provide a signal representing the mechanical vibrations. A harmonic balancing signal is generated for selected harmonics of the operating frequency by processing the sensed vibration signal with adaptive filter algorithms of adaptive filters for each harmonic. Reference inputs for each harmonic are applied to the adaptive filter algorithms at the frequency of the selected harmonic. The harmonic balancing signals for all of the harmonics are summed with a principal control signal. The harmonic balancing signals modify the principal electrical drive voltage and drive the motor/alternator with a drive voltage component in opposition to the vibration at each harmonic.

Drivers' social-work relationships as antecedents of unsafe driving: A social network perspective.

PubMed

Arizon Peretz, Renana; Luria, Gil

2017-09-01

In order to reduce road accidents rates, studies around the globe have attempted to shed light on the antecedents for unsafe road behaviors. The aim of the current research is to contribute to this literature by offering a new organizational antecedent of driver's unsafe behavior: The driver's relationships with his or her peers, as reflected in three types of social networks: negative relationships network, friendship networks and advice networks (safety consulting). We hypothesized that a driver's position in negative relationship networks, friendship networks, and advice networks will predict unsafe driving. Additionally, we hypothesized the existence of mutual influences among the driver's positions in these various networks, and suggested that the driver's positions interact to predict unsafe driving behaviors. The research included 83 professional drivers from four different organizations. Driving behavior data were gathered via the IVDR (In-Vehicle Data Recorder) system, installed in every truck to measure and record the driver's behavior. The findings indicated that the drivers' position in the team networks predicts safe driving behavior: Centrality in negative relationship networks is positively related to unsafe driving, and centrality in friendship networks is negatively related to unsafe driving, while centrality in advice networks is not related to unsafe driving. Furthermore, we found an interaction effect between negative network centrality and centrality in friendship networks. The relation between negative networks and unsafe behavior is weaker when high levels of friendship network centrality exist. The implications will be presented in the Discussion section. Copyright © 2017 Elsevier Ltd. All rights reserved.

Measuring Risky Driving Behavior Using an mHealth Smartphone App: Development and Evaluation of gForce

PubMed Central

Dave, Amisha D; Espey, Benjamin G; Stanley, Sean T; Garmendia, Marcial A; Pursley, Randall; Ehsani, Johnathon P; Simons-Morton, Bruce G; Pohida, Thomas J

2018-01-01

Background Naturalistic driving studies, designed to objectively assess driving behavior and outcomes, are conducted by equipping vehicles with dedicated instrumentation (eg, accelerometers, gyroscopes, Global Positioning System, and cameras) that provide continuous recording of acceleration, location, videos, and still images for eventual retrieval and analyses. However, this research is limited by several factors: the cost of equipment installation; management and storage of the large amounts of data collected; and data reduction, coding, and analyses. Modern smartphone technology includes accelerometers built into phones, and the vast, global proliferation of smartphones could provide a possible low-cost alternative for assessing kinematic risky driving. Objective We evaluated an in-house developed iPhone app (gForce) for detecting elevated g-force events by comparing the iPhone linear acceleration measurements with corresponding acceleration measurements obtained with both a custom Android app and the in-vehicle miniDAS data acquisition system (DAS; Virginia Tech Transportation Institute). Methods The iPhone and Android devices were dashboard-mounted in a vehicle equipped with the DAS instrumentation. The experimental protocol consisted of driving maneuvers on a test track, such as cornering, braking, and turning that were performed at different acceleration levels (ie, mild, moderate, or hard). The iPhone gForce app recorded linear acceleration (ie, gravity-corrected). The Android app recorded gravity-corrected and uncorrected acceleration measurements, and the DAS device recorded gravity-uncorrected acceleration measurements. Lateral and longitudinal acceleration measures were compared. Results The correlation coefficients between the iPhone and DAS acceleration measurements were slightly lower compared to the correlation coefficients between the Android and DAS, possibly due to the gravity correction on the iPhone. Averaging the correlation coefficients for all maneuvers, the longitudinal and lateral acceleration measurements between iPhone and DAS were rlng=0.71 and rlat=0.83, respectively, while the corresponding acceleration measurements between Android and DAS were rlng=0.95 and rlat=0.97. The correlation coefficients between lateral accelerations on all three devices were higher than with the corresponding longitudinal accelerations for most maneuvers. Conclusions The gForce iPhone app reliably assessed elevated g-force events compared to the DAS. Collectively, the gForce app and iPhone platform have the potential to serve as feature-rich, inexpensive, scalable, and open-source tool for assessment of kinematic risky driving events, with potential for research and feedback forms of intervention. PMID:29674309

Impact of distraction on the driving performance of adolescents with and without attention-deficit/hyperactivity disorder.

PubMed

Narad, Megan; Garner, Annie A; Brassell, Anne A; Saxby, Dyani; Antonini, Tanya N; O'Brien, Kathleen M; Tamm, Leanne; Matthews, Gerald; Epstein, Jeffery N

2013-10-01

This study extends the literature regarding attention-deficit/hyperactivity disorder (ADHD)-related driving impairments to a newly licensed, adolescent population. To investigate the combined risks of adolescence, ADHD, and distracted driving (cell phone conversation and text messaging) on driving performance. Adolescents aged 16 to 17 years with (n = 28) and without (n = 33) ADHD engaged in a simulated drive under 3 conditions (no distraction, cell phone conversation, and texting). During each condition, one unexpected event (eg, another car suddenly merging into driver's lane) was introduced. Cell phone conversation, texting, and no distraction while driving. Self-report of driving history, average speed, standard deviation of speed, standard deviation of lateral position, and braking reaction time during driving simulation. Adolescents with ADHD reported fewer months of driving experience and a higher proportion of driving violations than control subjects. After controlling for months of driving history, adolescents with ADHD demonstrated more variability in speed and lane position than control subjects. There were no group differences for braking reaction time. Furthermore, texting negatively impacted the driving performance of all participants as evidenced by increased variability in speed and lane position. To our knowledge, this study is one of the first to investigate distracted driving in adolescents with ADHD and adds to a growing body of literature documenting that individuals with ADHD are at increased risk for negative driving outcomes. Furthermore, texting significantly impairs the driving performance of all adolescents and increases existing driving-related impairment in adolescents with ADHD, highlighting the need for education and enforcement of regulations against texting for this age group.

Awareness of driving disability in people with stroke tested in a simulator.

PubMed

Patomella, Ann-Helen; Kottorp, Anders; Tham, Kerstin

2008-09-01

The aim of this study was to explore and describe awareness of driving disability in people with driving difficulties after stroke. The study comprised a consecutive sample of 38 participants with stroke who showed difficulties in a technically advanced, interactive driving simulator. Driving ability in the simulator was measured using Performance Analysis of Driving Ability (P-Drive). Awareness of driving disability was measured using a modified version of Assessment of Awareness of Disability (AAD), measuring the discrepancy between observed driving actions and self-reported disability after a driving evaluation in a simulator. A majority of the participants (n = 36) demonstrated driving ability that was below the cut-off criterion for P-Drive. Furthermore, a majority of the items measuring awareness of driving disability were scored low, indicating that participants with stroke who did not pass a driving evaluation also had limited awareness of driving disability. A General Linear Model analysis indicated that awareness of driving disability and cognitive screening outcome explained 74% of the variance in driving ability. This study indicated that a majority of the people with stroke who fail a driving evaluation also have limited awareness of their disability, which indicates the need to address awareness in driving evaluations.

Ramp and periodic dynamics across non-Ising critical points

NASA Astrophysics Data System (ADS)

Ghosh, Roopayan; Sen, Arnab; Sengupta, K.

2018-01-01

We study ramp and periodic dynamics of ultracold bosons in an one-dimensional (1D) optical lattice which supports quantum critical points separating a uniform and a Z3 or Z4 symmetry broken density-wave ground state. Our protocol involves both linear and periodic drives which takes the system from the uniform state to the quantum critical point (for linear drive protocol) or to the ordered state and back (for periodic drive protocols) via controlled variation of a parameter of the system Hamiltonian. We provide exact numerical computation, for finite-size boson chains with L ≤24 using exact diagonalization (ED), of the excitation density D , the wave function overlap F , and the excess energy Q at the end of the drive protocol. For the linear ramp protocol, we identify the range of ramp speeds for which D and Q show Kibble-Zurek scaling. We find, based on numerical analysis with L ≤24 , that such scaling is consistent with that expected from critical exponents of the q -state Potts universality class with q =3 ,4 . For the periodic protocol, we show that the model displays near-perfect dynamical freezing at specific frequencies; at these frequencies D ,Q →0 and |F |→1 . We provide a semi-analytic explanation of such freezing behavior and relate this phenomenon to a many-body version of Stuckelberg interference. We suggest experiments which can test our theory.

Automation system for measurement of gamma-ray spectra of induced activity for multi-element high volume neutron activation analysis at the reactor IBR-2 of Frank Laboratory of Neutron Physics at the joint institute for nuclear research

NASA Astrophysics Data System (ADS)

Pavlov, S. S.; Dmitriev, A. Yu.; Chepurchenko, I. A.; Frontasyeva, M. V.

2014-11-01

The automation system for measurement of induced activity of gamma-ray spectra for multi-element high volume neutron activation analysis (NAA) was designed, developed and implemented at the reactor IBR-2 at the Frank Laboratory of Neutron Physics. The system consists of three devices of automatic sample changers for three Canberra HPGe detector-based gamma spectrometry systems. Each sample changer consists of two-axis of linear positioning module M202A by DriveSet company and disk with 45 slots for containers with samples. Control of automatic sample changer is performed by the Xemo S360U controller by Systec company. Positioning accuracy can reach 0.1 mm. Special software performs automatic changing of samples and measurement of gamma spectra at constant interaction with the NAA database.

Standard operation procedures for conducting the on-the-road driving test, and measurement of the standard deviation of lateral position (SDLP)

PubMed Central

Verster, Joris C; Roth, Thomas

2011-01-01

This review discusses the methodology of the standardized on-the-road driving test and standard operation procedures to conduct the test and analyze the data. The on-the-road driving test has proven to be a sensitive and reliable method to examine driving ability after administration of central nervous system (CNS) drugs. The test is performed on a public highway in normal traffic. Subjects are instructed to drive with a steady lateral position and constant speed. Its primary parameter, the standard deviation of lateral position (SDLP), ie, an index of ‘weaving’, is a stable measure of driving performance with high test–retest reliability. SDLP differences from placebo are dose-dependent, and do not depend on the subject’s baseline driving skills (placebo SDLP). It is important that standard operation procedures are applied to conduct the test and analyze the data in order to allow comparisons between studies from different sites. PMID:21625472

Standard operation procedures for conducting the on-the-road driving test, and measurement of the standard deviation of lateral position (SDLP).

PubMed

Verster, Joris C; Roth, Thomas

2011-01-01

This review discusses the methodology of the standardized on-the-road driving test and standard operation procedures to conduct the test and analyze the data. The on-the-road driving test has proven to be a sensitive and reliable method to examine driving ability after administration of central nervous system (CNS) drugs. The test is performed on a public highway in normal traffic. Subjects are instructed to drive with a steady lateral position and constant speed. Its primary parameter, the standard deviation of lateral position (SDLP), ie, an index of 'weaving', is a stable measure of driving performance with high test-retest reliability. SDLP differences from placebo are dose-dependent, and do not depend on the subject's baseline driving skills (placebo SDLP). It is important that standard operation procedures are applied to conduct the test and analyze the data in order to allow comparisons between studies from different sites.

The Impact of Distraction on the Driving Performance of Adolescents with and without Attention Deficit Hyperactivity Disorder

PubMed Central

Narad, Megan; Garner, Annie A.; Brassell, Anne A.; Saxby, Dyani; Antonini, Tanya N.; O'Brien, Kathleen M.; Tamm, Leanne; Matthews, Gerald; Epstein, Jeffery N.

2013-01-01

Importance This study extends the literature regarding Attention-Deficit/Hyperactivity Disorder (ADHD) related driving impairments to a newly-licensed, adolescent population. Objective To investigate the combined risks of adolescence, ADHD, and distracted driving (cell phone conversation and text messaging) on driving performance. Design Adolescents with and without ADHD engaged in a simulated drive under three conditions (no distraction, cell phone conversation, texting). During each condition, one unexpected event (e.g., car suddenly merging into driver's lane) was introduced. Setting Driving simulator. Participants Adolescents aged 16–17 with ADHD (n=28) and controls (n=33). Interventions/Main Exposures Cell phone conversation, texting, and no distraction while driving. Outcome Measures Self-report of driving history; Average speed, standard deviation of speed, standard deviation of lateral position, braking reaction time during driving simulation. Results Adolescents with ADHD reported fewer months of driving experience and a higher proportion of driving violations than controls. After controlling for months of driving history, adolescents with ADHD demonstrated more variability in speed and lane position than controls. There were no group differences for braking reaction time. Further, texting negatively impacted the driving performance of all participants as evidenced by increased variability in speed and lane position. Conclusions This study, one of the first to investigate distracted driving in adolescents with ADHD, adds to a growing body of literature documenting that individuals with ADHD are at increased risk for negative driving outcomes. Furthermore, texting significantly impairs the driving performance of all adolescents and increases existing driving-related impairment in adolescents with ADHD, highlighting the need for education and enforcement of regulations against texting for this age group. PMID:23939758

Single-Molecule Encoders for Tracking Motor Proteins on DNA

NASA Astrophysics Data System (ADS)

Lipman, Everett A.

2012-02-01

Devices such as inkjet printers and disk drives track position and velocity using optical encoders, which produce periodic signals precisely synchronized with linear or rotational motion. We have implemented this technique at the nanometer scale by labeling DNA with regularly spaced fluorescent dyes. The resulting molecular encoders can be used in several ways for high-resolution continuous tracking of individual motor proteins. These measurements do not require mechanical coupling to macroscopic instrumentation, are automatically calibrated by the underlying structure of DNA, and depend on signal periodicity rather than absolute level. I will describe the synthesis of single-molecule encoders, data from and modeling of experiments on a helicase and a DNA polymerase, and some ideas for future work.

Computing Linear Mathematical Models Of Aircraft

NASA Technical Reports Server (NTRS)

Duke, Eugene L.; Antoniewicz, Robert F.; Krambeer, Keith D.

1991-01-01

Derivation and Definition of Linear Aircraft Model (LINEAR) computer program provides user with powerful, and flexible, standard, documented, and verified software tool for linearization of mathematical models of aerodynamics of aircraft. Intended for use in software tool to drive linear analysis of stability and design of control laws for aircraft. Capable of both extracting such linearized engine effects as net thrust, torque, and gyroscopic effects, and including these effects in linear model of system. Designed to provide easy selection of state, control, and observation variables used in particular model. Also provides flexibility of allowing alternate formulations of both state and observation equations. Written in FORTRAN.

[Effects of climate and grazing on the vegetation cover change in Xilinguole League of Inner Mongolia, North China].

PubMed

Wang, Hai-Mei; Li, Zheng-Hai; Wang, Zhen

2013-01-01

Based on the monthly temperature and precipitation data of 15 meteorological stations and the statistical data of livestock density in Xilinguole League in 1981-2007, and by using ArcGIS, this paper analyzed the spatial distribution of the climate aridity and livestock density in the League, and in combining with the ten-day data of the normalized difference vegetation index (NDVI) in 1981-2007, the driving factors of the vegetation cover change in the League were discussed. In the study period, there was a satisfactory linear regression relationship between the climate aridity and the vegetation coverage. The NDVI and the livestock density had a favorable binomial regression relationship. With the increase of NDVI, the livestock density increased first and decreased then. The vegetation coverage had a complex linear relationship with livestock density and climate aridity. The NDVI had a positive correlation with climate aridity, but a negative correlation with livestock density. Compared with livestock density, climate aridity had far greater effects on the NDVI.

Training driving ability in a traumatic brain-injured individual using a driving simulator: a case report.

PubMed

Imhoff, Sarah; Lavallière, Martin; Germain-Robitaille, Mathieu; Teasdale, Normand; Fait, Philippe

2017-01-01

Traumatic brain injury (TBI) causes functional deficits that may significantly interfere with numerous activities of daily living such as driving. We report the case of a 20-year-old woman having lost her driver's license after sustaining a moderate TBI. We aimed to evaluate the effectiveness of an in-simulator training program with automated feedback on driving performance in a TBI individual. The participant underwent an initial and a final in-simulator driving assessment and 11 in-simulator training sessions with driving-specific automated feedbacks. Driving performance (simulation duration, speed regulation and lateral positioning) was measured in the driving simulator. Speeding duration decreased during training sessions from 1.50 ± 0.80 min (4.16 ± 2.22%) to 0.45 ± 0.15 min (0.44 ± 0.42%) but returned to initial duration after removal of feedbacks for the final assessment. Proper lateral positioning improved with training and was maintained at the final assessment. Time spent in an incorrect lateral position decreased from 18.85 min (53.61%) in the initial assessment to 1.51 min (4.64%) on the final assessment. Driving simulators represent an interesting therapeutic avenue. Considerable research efforts are needed to confirm the effectiveness of this method for driving rehabilitation of individuals who have sustained a TBI.

Monitoring sleepiness with on-board electrophysiological recordings for preventing sleep-deprived traffic accidents.

PubMed

Papadelis, Christos; Chen, Zhe; Kourtidou-Papadeli, Chrysoula; Bamidis, Panagiotis D; Chouvarda, Ioanna; Bekiaris, Evangelos; Maglaveras, Nikos

2007-09-01

The objective of this study is the development and evaluation of efficient neurophysiological signal statistics, which may assess the driver's alertness level and serve as potential indicators of sleepiness in the design of an on-board countermeasure system. Multichannel EEG, EOG, EMG, and ECG were recorded from sleep-deprived subjects exposed to real field driving conditions. A number of severe driving errors occurred during the experiments. The analysis was performed in two main dimensions: the macroscopic analysis that estimates the on-going temporal evolution of physiological measurements during the driving task, and the microscopic event analysis that focuses on the physiological measurements' alterations just before, during, and after the driving errors. Two independent neurophysiologists visually interpreted the measurements. The EEG data were analyzed by using both linear and non-linear analysis tools. We observed the occurrence of brief paroxysmal bursts of alpha activity and an increased synchrony among EEG channels before the driving errors. The alpha relative band ratio (RBR) significantly increased, and the Cross Approximate Entropy that quantifies the synchrony among channels also significantly decreased before the driving errors. Quantitative EEG analysis revealed significant variations of RBR by driving time in the frequency bands of delta, alpha, beta, and gamma. Most of the estimated EEG statistics, such as the Shannon Entropy, Kullback-Leibler Entropy, Coherence, and Cross-Approximate Entropy, were significantly affected by driving time. We also observed an alteration of eyes blinking duration by increased driving time and a significant increase of eye blinks' number and duration before driving errors. EEG and EOG are promising neurophysiological indicators of driver sleepiness and have the potential of monitoring sleepiness in occupational settings incorporated in a sleepiness countermeasure device. The occurrence of brief paroxysmal bursts of alpha activity before severe driving errors is described in detail for the first time. Clear evidence is presented that eye-blinking statistics are sensitive to the driver's sleepiness and should be considered in the design of an efficient and driver-friendly sleepiness detection countermeasure device.

Impacts of agricultural management and climate change on future soil organic carbon dynamics in North China Plain.

PubMed

Wang, Guocheng; Li, Tingting; Zhang, Wen; Yu, Yongqiang

2014-01-01

Dynamics of cropland soil organic carbon (SOC) in response to different management practices and environmental conditions across North China Plain (NCP) were studied using a modeling approach. We identified the key variables driving SOC changes at a high spatial resolution (10 km × 10 km) and long time scale (90 years). The model used future climatic data from the FGOALS model based on four future greenhouse gas (GHG) concentration scenarios. Agricultural practices included different rates of nitrogen (N) fertilization, manure application, and stubble retention. We found that SOC change was significantly influenced by the management practices of stubble retention (linearly positive), manure application (linearly positive) and nitrogen fertilization (nonlinearly positive) - and the edaphic variable of initial SOC content (linearly negative). Temperature had weakly positive effects, while precipitation had negligible impacts on SOC dynamics under current irrigation management. The effects of increased N fertilization on SOC changes were most significant between the rates of 0 and 300 kg ha-1 yr-1. With a moderate rate of manure application (i.e., 2000 kg ha-1 yr-1), stubble retention (i.e., 50%), and an optimal rate of nitrogen fertilization (i.e., 300 kg ha-1 yr-1), more than 60% of the study area showed an increase in SOC, and the average SOC density across NCP was relatively steady during the study period. If the rates of manure application and stubble retention doubled (i.e., manure application rate of 4000 kg ha-1 yr-1 and stubble retention rate of 100%), soils across more than 90% of the study area would act as a net C sink, and the average SOC density kept increasing from 40 Mg ha-1 during 2010s to the current worldwide average of ∼ 55 Mg ha-1 during 2060s. The results can help target agricultural management practices for effectively mitigating climate change through soil C sequestration.

Impacts of Agricultural Management and Climate Change on Future Soil Organic Carbon Dynamics in North China Plain

PubMed Central

Wang, Guocheng; Li, Tingting; Zhang, Wen; Yu, Yongqiang

2014-01-01

Dynamics of cropland soil organic carbon (SOC) in response to different management practices and environmental conditions across North China Plain (NCP) were studied using a modeling approach. We identified the key variables driving SOC changes at a high spatial resolution (10 km×10 km) and long time scale (90 years). The model used future climatic data from the FGOALS model based on four future greenhouse gas (GHG) concentration scenarios. Agricultural practices included different rates of nitrogen (N) fertilization, manure application, and stubble retention. We found that SOC change was significantly influenced by the management practices of stubble retention (linearly positive), manure application (linearly positive) and nitrogen fertilization (nonlinearly positive) – and the edaphic variable of initial SOC content (linearly negative). Temperature had weakly positive effects, while precipitation had negligible impacts on SOC dynamics under current irrigation management. The effects of increased N fertilization on SOC changes were most significant between the rates of 0 and 300 kg ha−1 yr−1. With a moderate rate of manure application (i.e., 2000 kg ha−1 yr−1), stubble retention (i.e., 50%), and an optimal rate of nitrogen fertilization (i.e., 300 kg ha−1 yr−1), more than 60% of the study area showed an increase in SOC, and the average SOC density across NCP was relatively steady during the study period. If the rates of manure application and stubble retention doubled (i.e., manure application rate of 4000 kg ha−1 yr−1 and stubble retention rate of 100%), soils across more than 90% of the study area would act as a net C sink, and the average SOC density kept increasing from 40 Mg ha−1 during 2010s to the current worldwide average of ∼55 Mg ha−1 during 2060s. The results can help target agricultural management practices for effectively mitigating climate change through soil C sequestration. PMID:24722689

Turbulent current drive mechanisms

NASA Astrophysics Data System (ADS)

McDevitt, Christopher J.; Tang, Xian-Zhu; Guo, Zehua

2017-08-01

Mechanisms through which plasma microturbulence can drive a mean electron plasma current are derived. The efficiency through which these turbulent contributions can drive deviations from neoclassical predictions of the electron current profile is computed by employing a linearized Coulomb collision operator. It is found that a non-diffusive contribution to the electron momentum flux as well as an anomalous electron-ion momentum exchange term provide the most efficient means through which turbulence can modify the mean electron current for the cases considered. Such turbulent contributions appear as an effective EMF within Ohm's law and hence provide an ideal means for driving deviations from neoclassical predictions.

Inertial piezoelectric linear motor driven by a single-phase harmonic wave with automatic clamping mechanism

NASA Astrophysics Data System (ADS)

He, Liangguo; Chu, Yuheng; Hao, Sai; Zhao, Xiaoyong; Dong, Yuge; Wang, Yong

2018-05-01

A novel, single-phase, harmonic-driven, inertial piezoelectric linear motor using an automatic clamping mechanism was designed, fabricated, and tested to reduce the sliding friction and simplify the drive mechanism and power supply control of the inertial motor. A piezoelectric bimorph and a flexible hinge were connected in series to form the automatic clamping mechanism. The automatic clamping mechanism was used as the driving and clamping elements. A dynamic simulation by Simulink was performed to prove the feasibility of the motor. The finite element method software COMSOL was used to design the structure of the motor. An experimental setup was built to validate the working principle and evaluate the performance of the motor. The prototype motor outputted a no-load velocity of 3.178 mm/s at a voltage of 220 Vp-p and a maximum traction force of 4.25 N under a preload force of 8 N. The minimum resolution of 1.14 μm was achieved at a driving frequency of 74 Hz, a driving voltage of 50 Vp-p, and a preload force of 0 N.

Ultrafast probing of magnetic field growth inside a laser-driven solenoid

NASA Astrophysics Data System (ADS)

Goyon, C.; Pollock, B. B.; Turnbull, D. P.; Hazi, A.; Divol, L.; Farmer, W. A.; Haberberger, D.; Javedani, J.; Johnson, A. J.; Kemp, A.; Levy, M. C.; Grant Logan, B.; Mariscal, D. A.; Landen, O. L.; Patankar, S.; Ross, J. S.; Rubenchik, A. M.; Swadling, G. F.; Williams, G. J.; Fujioka, S.; Law, K. F. F.; Moody, J. D.

2017-03-01

We report on the detection of the time-dependent B-field amplitude and topology in a laser-driven solenoid. The B-field inferred from both proton deflectometry and Faraday rotation ramps up linearly in time reaching 210 ± 35 T at the end of a 0.75-ns laser drive with 1 TW at 351 nm. A lumped-element circuit model agrees well with the linear rise and suggests that the blow-off plasma screens the field between the plates leading to an increased plate capacitance that converts the laser-generated hot-electron current into a voltage source that drives current through the solenoid. ALE3D modeling shows that target disassembly and current diffusion may limit the B-field increase for longer laser drive. Scaling of these experimental results to a National Ignition Facility (NIF) hohlraum target size (˜0.2 cm3 ) indicates that it is possible to achieve several tens of Tesla.

Ultrafast probing of magnetic field growth inside a laser-driven solenoid.

PubMed

Goyon, C; Pollock, B B; Turnbull, D P; Hazi, A; Divol, L; Farmer, W A; Haberberger, D; Javedani, J; Johnson, A J; Kemp, A; Levy, M C; Grant Logan, B; Mariscal, D A; Landen, O L; Patankar, S; Ross, J S; Rubenchik, A M; Swadling, G F; Williams, G J; Fujioka, S; Law, K F F; Moody, J D

2017-03-01

We report on the detection of the time-dependent B-field amplitude and topology in a laser-driven solenoid. The B-field inferred from both proton deflectometry and Faraday rotation ramps up linearly in time reaching 210 ± 35 T at the end of a 0.75-ns laser drive with 1 TW at 351 nm. A lumped-element circuit model agrees well with the linear rise and suggests that the blow-off plasma screens the field between the plates leading to an increased plate capacitance that converts the laser-generated hot-electron current into a voltage source that drives current through the solenoid. ALE3D modeling shows that target disassembly and current diffusion may limit the B-field increase for longer laser drive. Scaling of these experimental results to a National Ignition Facility (NIF) hohlraum target size (∼0.2cm^{3}) indicates that it is possible to achieve several tens of Tesla.

An extended car-following model considering random safety distance with different probabilities

NASA Astrophysics Data System (ADS)

Wang, Jufeng; Sun, Fengxin; Cheng, Rongjun; Ge, Hongxia; Wei, Qi

2018-02-01

Because of the difference in vehicle type or driving skill, the driving strategy is not exactly the same. The driving speeds of the different vehicles may be different for the same headway. Since the optimal velocity function is just determined by the safety distance besides the maximum velocity and headway, an extended car-following model accounting for random safety distance with different probabilities is proposed in this paper. The linear stable condition for this extended traffic model is obtained by using linear stability theory. Numerical simulations are carried out to explore the complex phenomenon resulting from multiple safety distance in the optimal velocity function. The cases of multiple types of safety distances selected with different probabilities are presented. Numerical results show that the traffic flow with multiple safety distances with different probabilities will be more unstable than that with single type of safety distance, and will result in more stop-and-go phenomena.

Evolution from MEMS-based Linear Drives to Bio-based Nano Drives

NASA Astrophysics Data System (ADS)

Fujita, Hiroyuki

The successful extension of semiconductor technology to fabricate mechanical parts of the sizes from 10 to 100 micrometers opened wide ranges of possibilities for micromechanical devices and systems. The fabrication technique is called micromachining. Micromachining processes are based on silicon integrated circuits (IC) technology and used to build three-dimensional structures and movable parts by the combination of lithography, etching, film deposition, and wafer bonding. Microactuators are the key devices allowing MEMS to perform physical functions. Some of them are driven by electric, magnetic, and fluidic forces. Some others utilize actuator materials including piezoelectric (PZT, ZnO, quartz) and magnetostrictive materials (TbFe), shape memory alloy (TiNi) and bio molecular motors. This paper deals with the development of MEMS based microactuators, especially linear drives, following my own research experience. They include an electrostatic actuator, a superconductive levitated actuator, arrayed actuators, and a bio-motor-driven actuator.

Strong quantum squeezing of mechanical resonator via parametric amplification and coherent feedback

NASA Astrophysics Data System (ADS)

You, Xiang; Li, Zongyang; Li, Yongmin

2017-12-01

A scheme to achieve strong quantum squeezing of a mechanical resonator in a membrane-in-the-middle optomechanical system is developed. To this end, simultaneous linear and nonlinear coupling between the mechanical resonator and the cavity modes is applied. A two-tone driving light field, comprising unequal red-detuned and blue-detuned sidebands, helps in generating a coherent feedback force through the linear coupling with the membrane resonator. Another driving light field with its amplitude modulated at twice the mechanical frequency drives the mechanical parametric amplification through a second-order coupling with the resonator. The combined effect produces strong quantum squeezing of the mechanical state. The proposed scheme is quite robust to excess second-order coupling observed in coherent feedback operations and can suppress the fluctuations in the mechanical quadrature to far below the zero point and achieve strong squeezing (greater than 10 dB) for realistic parameters.

A U-shaped linear ultrasonic motor using longitudinal vibration transducers with double feet.

PubMed

Liu, Yingxiang; Liu, Junkao; Chen, Weishan; Shi, Shengjun

2012-05-01

A U-shaped linear ultrasonic motor using longitudinal vibration transducers with double feet was proposed in this paper. The proposed motor contains a horizontal transducer and two vertical transducers. The horizontal transducer includes two exponential shape horns located at the leading ends, and each vertical transducer contains one exponential shape horn. The horns of the horizontal transducer and the vertical transducer intersect at the tip ends where the driving feet are located. Longitudinal vibrations are superimposed in the motor and generate elliptical motions at the driving feet. The two vibration modes of the motor are discussed, and the motion trajectories of driving feet are deduced. By adjusting the structural parameters, the resonance frequencies of two vibration modes were degenerated. A prototype motor was fabricated and measured. Typical output of the prototype is no-load speed of 854 mm/s and maximum thrust force of 40 N at a voltage of 200 V(rms).

Numerical linear analysis of the effects of diamagnetic and shear flow on ballooning modes

NASA Astrophysics Data System (ADS)

Yanqing, HUANG; Tianyang, XIA; Bin, GUI

2018-04-01

The linear analysis of the influence of diamagnetic effect and toroidal rotation at the edge of tokamak plasmas with BOUT++ is discussed in this paper. This analysis is done by solving the dispersion relation, which is calculated through the numerical integration of the terms with different physics. This method is able to reveal the contributions of the different terms to the total growth rate. The diamagnetic effect stabilizes the ideal ballooning modes through inhibiting the contribution of curvature. The toroidal rotation effect is also able to suppress the curvature-driving term, and the stronger shearing rate leads to a stronger stabilization effect. In addition, through linear analysis using the energy form, the curvature-driving term provides the free energy absorbed by the line-bending term, diamagnetic term and convective term.

Engineering non-linear resonator mode interactions in circuit QED by continuous driving: Introduction

NASA Astrophysics Data System (ADS)

Pfaff, Wolfgang; Reagor, Matthew; Heeres, Reinier; Ofek, Nissim; Chou, Kevin; Blumoff, Jacob; Leghtas, Zaki; Touzard, Steven; Sliwa, Katrina; Holland, Eric; Krastanov, Stefan; Frunzio, Luigi; Devoret, Michel; Jiang, Liang; Schoelkopf, Robert

2015-03-01

High-Q microwave resonators show great promise for storing and manipulating quantum states in circuit QED. Using resonator modes as such a resource in quantum information processing applications requires the ability to manipulate the state of a resonator efficiently. Further, one must engineer appropriate coupling channels without spoiling the coherence properties of the resonator. We present an architecture that combines millisecond lifetimes for photonic quantum states stored in a linear resonator with fast measurement provided by a low-Q readout resonator. We demonstrate experimentally how a continuous drive on a transmon can be utilized to generate highly non-classical photonic states inside the high-Q resonator via effective nonlinear resonator mode interactions. Our approach opens new avenues for using modes of long-lived linear resonators in the circuit QED platform for quantum information processing tasks.

Adaptive nonsingular terminal sliding mode controller for micro/nanopositioning systems driven by linear piezoelectric ceramic motors.

PubMed

Safa, Alireza; Abdolmalaki, Reza Yazdanpanah; Shafiee, Saeed; Sadeghi, Behzad

2018-06-01

In the field of nanotechnology, there is a growing demand to provide precision control and manipulation of devices with the ability to interact with complex and unstructured environments at micro/nano-scale. As a result, ultrahigh-precision positioning stages have been turned into a key requirement of nanotechnology. In this paper, linear piezoelectric ceramic motors (LPCMs) are adopted to drive micro/nanopositioning stages since they have the ability to achieve high precision in addition to being versatile to be implemented over a wide range of applications. In the establishment of a control scheme for such manipulation systems, the presence of friction, parameter uncertainties, and external disturbances prevent the systems from providing the desired positioning accuracy. The work in this paper focuses on the development of a control framework that addresses these issues as it uses the nonsingular terminal sliding mode technique for the precise position tracking problem of an LPCM-driven positioning stage with friction, uncertain parameters, and external disturbances. The developed control algorithm exhibits the following two attractive features. First, upper bounds of system uncertainties/perturbations are adaptively estimated in the proposed controller; thus, prior knowledge about uncertainty/disturbance bounds is not necessary. Second, the discontinuous signum function is transferred to the time derivative of the control input and the continuous control signal is obtained after integration; consequently, the chattering phenomenon, which presents a major handicap to the implementation of conventional sliding mode control in real applications, is alleviated without deteriorating the robustness of the system. The stability of the controlled system is analyzed, and the convergence of the position tracking error to zero is analytically proven. The proposed control strategy is experimentally validated and compared to the existing control approaches. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

[Variation of CAG repeats in coding region of ATXN2 gene in different ethnic groups].

PubMed

Chen, Xiao-Chen; Sun, Hao; Mi, Dong-Qing; Huang, Xiao-Qin; Lin, Ke-Qin; Yi, Wen; Yu, Liang; Shi, Lei; Shi, Li; Yang, Zhao-Qing; Chu, Jia-You

2011-04-01

Toinvestigate CAG repeats variation of ATXN2 gene coding region in six ethnic groups that live in comparatively different environments, to evaluate whether these variations are under positive selection, and to find factors driving selection effects, 291 unrelated healthy individuals were collected from six ethnic groups and their STR geneotyping was performed. The frequencies of alleles and genotypes were counted and thereby Slatkin's linearized Fst values were calculated. The UPGMA tree against this gene was constructed. The MDS analysis among these groups was carried out as well. The results from the linearized Fst values indicated that there were significant evolutionary differences of the STR in ATXN2 gene between Hui and Yi groups, but not among the other 4 groups. Further analysis was performed by combining our data with published data obtained from other groups. These results indicated that there were significant differences between Japanese and other groups including Hui, Hani, Yunnan Mongolian, and Inner Mongolian. Both Hui and Mongolian from Inner Mongolia were significantly different from Han. In conclusion, the six ethnic groups had their own distribution characterizations of allelic frequencies of ATXN2 STR, and the potential cause of frequency changes in rare alleles could be the consequence of positive selection.

Real-time control of hind limb functional electrical stimulation using feedback from dorsal root ganglia recordings

NASA Astrophysics Data System (ADS)

Bruns, Tim M.; Wagenaar, Joost B.; Bauman, Matthew J.; Gaunt, Robert A.; Weber, Douglas J.

2013-04-01

Objective. Functional electrical stimulation (FES) approaches often utilize an open-loop controller to drive state transitions. The addition of sensory feedback may allow for closed-loop control that can respond effectively to perturbations and muscle fatigue. Approach. We evaluated the use of natural sensory nerve signals obtained with penetrating microelectrode arrays in lumbar dorsal root ganglia (DRG) as real-time feedback for closed-loop control of FES-generated hind limb stepping in anesthetized cats. Main results. Leg position feedback was obtained in near real-time at 50 ms intervals by decoding the firing rates of more than 120 DRG neurons recorded simultaneously. Over 5 m of effective linear distance was traversed during closed-loop stepping trials in each of two cats. The controller compensated effectively for perturbations in the stepping path when DRG sensory feedback was provided. The presence of stimulation artifacts and the quality of DRG unit sorting did not significantly affect the accuracy of leg position feedback obtained from the linear decoding model as long as at least 20 DRG units were included in the model. Significance. This work demonstrates the feasibility and utility of closed-loop FES control based on natural neural sensors. Further work is needed to improve the controller and electrode technologies and to evaluate long-term viability.

Real-time control of hind limb functional electrical stimulation using feedback from dorsal root ganglia recordings

PubMed Central

Bruns, Tim M; Wagenaar, Joost B; Bauman, Matthew J; Gaunt, Robert A; Weber, Douglas J

2013-01-01

Objective Functional electrical stimulation (FES) approaches often utilize an open-loop controller to drive state transitions. The addition of sensory feedback may allow for closed-loop control that can respond effectively to perturbations and muscle fatigue. Approach We evaluated the use of natural sensory nerve signals obtained with penetrating microelectrode arrays in lumbar dorsal root ganglia (DRG) as real-time feedback for closed-loop control of FES-generated hind limb stepping in anesthetized cats. Main results Leg position feedback was obtained in near real-time at 50 ms intervals by decoding the firing rates of more than 120 DRG neurons recorded simultaneously. Over 5 m of effective linear distance was traversed during closed-loop stepping trials in each of two cats. The controller compensated effectively for perturbations in the stepping path when DRG sensory feedback was provided. The presence of stimulation artifacts and the quality of DRG unit sorting did not significantly affect the accuracy of leg position feedback obtained from the linear decoding model as long as at least 20 DRG units were included in the model. Significance This work demonstrates the feasibility and utility of closed-loop FES control based on natural neural sensors. Further work is needed to improve the controller and electrode technologies and to evaluate long-term viability. PMID:23503062

Survey of the present state of the art of piezoelectric linear motors

PubMed

Hemsel; Wallaschek

2000-03-01

Piezoelectric ultrasonic motors have been investigated for several years and have already found their first practical applications. Their key feature is that they are able to produce a high thrust force related to their volume. Beside rotary drives like the travelling wave motor, linear drives have also been developed, but only a few are presently commercially available. In the present paper, we first describe the state of the art of linear piezoelectric motors. The motors are characterized with respect to their no-load velocity, maximum thrust force, efficiency and other technical properties. In the second part, we present a new motor, which is judged to be capable of surpassing the characteristics of other piezoelectric motors because of its unique design which allows the piezoelectric drive elements to be pre-stressed in the direction of their polarization. The piezoelectric elements convert energy using the longitudinal d33 effect which allows an improved reliability, large vibration amplitudes and excellent piezoelectric coupling. Energy loss by vibration damping is minimized, and the efficiency can be improved significantly. Experimental results show that the motor characteristics can be optimized for a particular task by choosing the appropriate operating parameters such as exciting voltage, exciting frequency and normal force.

Online Detection of Driver Fatigue Using Steering Wheel Angles for Real Driving Conditions.

PubMed

Li, Zuojin; Li, Shengbo Eben; Li, Renjie; Cheng, Bo; Shi, Jinliang

2017-03-02

This paper presents a drowsiness on-line detection system for monitoring driver fatigue level under real driving conditions, based on the data of steering wheel angles (SWA) collected from sensors mounted on the steering lever. The proposed system firstly extracts approximate entropy (ApEn)featuresfromfixedslidingwindowsonreal-timesteeringwheelanglestimeseries. Afterthat, this system linearizes the ApEn features series through an adaptive piecewise linear fitting using a given deviation. Then, the detection system calculates the warping distance between the linear features series of the sample data. Finally, this system uses the warping distance to determine the drowsiness state of the driver according to a designed binary decision classifier. The experimental data were collected from 14.68 h driving under real road conditions, including two fatigue levels: "wake" and "drowsy". The results show that the proposed system is capable of working online with an average 78.01% accuracy, 29.35% false detections of the "awake" state, and 15.15% false detections of the "drowsy" state. The results also confirm that the proposed method based on SWA signal is valuable for applications in preventing traffic accidents caused by driver fatigue.

Online Detection of Driver Fatigue Using Steering Wheel Angles for Real Driving Conditions

PubMed Central

Li, Zuojin; Li, Shengbo Eben; Li, Renjie; Cheng, Bo; Shi, Jinliang

2017-01-01

This paper presents a drowsiness on-line detection system for monitoring driver fatigue level under real driving conditions, based on the data of steering wheel angles (SWA) collected from sensors mounted on the steering lever. The proposed system firstly extracts approximate entropy (ApEn) features from fixed sliding windows on real-time steering wheel angles time series. After that, this system linearizes the ApEn features series through an adaptive piecewise linear fitting using a given deviation. Then, the detection system calculates the warping distance between the linear features series of the sample data. Finally, this system uses the warping distance to determine the drowsiness state of the driver according to a designed binary decision classifier. The experimental data were collected from 14.68 h driving under real road conditions, including two fatigue levels: “wake” and “drowsy”. The results show that the proposed system is capable of working online with an average 78.01% accuracy, 29.35% false detections of the “awake” state, and 15.15% false detections of the “drowsy” state. The results also confirm that the proposed method based on SWA signal is valuable for applications in preventing traffic accidents caused by driver fatigue. PMID:28257094

Single coil bistable, bidirectional micromechanical actuator

DOEpatents

Tabat, Ned; Guckel, Henry

1998-09-15

Micromechanical actuators capable of bidirectional and bistable operation can be formed on substrates using lithographic processing techniques. Bistable operation of the microactuator is obtained using a single coil and a magnetic core with a gap. A plunger having two magnetic heads is supported for back and forth linear movement with respect to the gap in the magnetic core, and is spring biased to a neutral position in which the two heads are on each side of the gap in the core. The single electrical coil is coupled to the core and is provided with electrical current to attract one of the heads toward the core by reluctance action to drive the plunger to a limit of travel in one direction. The current is then cut off and the plunger returns by spring action toward the gap, whereafter the current is reapplied to the coil to attract the other head of the plunger by reluctance action to drive the plunger to its other limit of travel. This process can be repeated at a time when switching of the actuator is required.

Thin Shell Model for NIF capsule stagnation studies

NASA Astrophysics Data System (ADS)

Hammer, J. H.; Buchoff, M.; Brandon, S.; Field, J. E.; Gaffney, J.; Kritcher, A.; Nora, R. C.; Peterson, J. L.; Spears, B.; Springer, P. T.

2015-11-01

We adapt the thin shell model of Ott et al. to asymmetric ICF capsule implosions on NIF. Through much of an implosion, the shell aspect ratio is large so the thin shell approximation is well satisfied. Asymmetric pressure drive is applied using an analytic form for ablation pressure as a function of the x-ray flux, as well as time-dependent 3D drive asymmetry from hohlraum calculations. Since deviations from a sphere are small through peak velocity, we linearize the equations, decompose them by spherical harmonics and solve ODE's for the coefficients. The model gives the shell position, velocity and areal mass variations at the time of peak velocity, near 250 microns radius. The variables are used to initialize 3D rad-hydro calculations with the HYDRA and ARES codes. At link time the cold fuel shell and ablator are each characterized by a density, adiabat and mass. The thickness, position and velocity of each point are taken from the thin shell model. The interior of the shell is filled with a uniform gas density and temperature consistent with the 3/2PV energy found from 1D rad-hydro calculations. 3D linked simulations compare favorably with integrated simulations of the entire implosion. Through generating synthetic diagnostic data, the model offers a method for quickly testing hypothetical sources of asymmetry and comparing with experiment. Prepared by LLNL under Contract DE-AC52-07NA27344.

The Technique of Changing the Drive Method of Micro Step Drive and Sensorless Drive for Hybrid Stepping Motor

NASA Astrophysics Data System (ADS)

Yoneda, Makoto; Dohmeki, Hideo

The position control system with the advantage large torque, low vibration, and high resolution can be obtained by the constant current micro step drive applied to hybrid stepping motor. However loss is large, in order not to be concerned with load torque but to control current uniformly. As the one technique of a position control system in which high efficiency is realizable, the same sensorless control as a permanent magnet motor is effective. But, it was the purpose that the control method proposed until now controls speed. Then, this paper proposed changing the drive method of micro step drive and sensorless drive. The change of the drive method was verified from the simulation and the experiment. On no load, it was checked not producing change of a large speed at the time of a change by making electrical angle and carrying out zero reset of the integrator. On load, it was checked that a large speed change arose. The proposed system could change drive method by setting up the initial value of an integrator using the estimated result, without producing speed change. With this technique, the low loss position control system, which employed the advantage of the hybrid stepping motor, has been built.

Training driving ability in a traumatic brain-injured individual using a driving simulator: a case report

PubMed Central

Imhoff, Sarah; Lavallière, Martin; Germain-Robitaille, Mathieu; Teasdale, Normand; Fait, Philippe

2017-01-01

Background Traumatic brain injury (TBI) causes functional deficits that may significantly interfere with numerous activities of daily living such as driving. We report the case of a 20-year-old woman having lost her driver’s license after sustaining a moderate TBI. Objective We aimed to evaluate the effectiveness of an in-simulator training program with automated feedback on driving performance in a TBI individual. Methods The participant underwent an initial and a final in-simulator driving assessment and 11 in-simulator training sessions with driving-specific automated feedbacks. Driving performance (simulation duration, speed regulation and lateral positioning) was measured in the driving simulator. Results Speeding duration decreased during training sessions from 1.50 ± 0.80 min (4.16 ± 2.22%) to 0.45 ± 0.15 min (0.44 ± 0.42%) but returned to initial duration after removal of feedbacks for the final assessment. Proper lateral positioning improved with training and was maintained at the final assessment. Time spent in an incorrect lateral position decreased from 18.85 min (53.61%) in the initial assessment to 1.51 min (4.64%) on the final assessment. Conclusion Driving simulators represent an interesting therapeutic avenue. Considerable research efforts are needed to confirm the effectiveness of this method for driving rehabilitation of individuals who have sustained a TBI. PMID:28243152

Effects of fatigue on driving performance under different roadway geometries: a simulator study.

PubMed

Du, Hongji; Zhao, Xiaohua; Zhang, Xingjian; Zhang, Yunlong; Rong, Jian

2015-01-01

This article examines the effects of fatigue on driving performance under different roadway geometries using a driving simulator. Twenty-four participants each completed a driving scenario twice: while alert and while experiencing fatigue. The driving scenario was composed of straight road segments and curves; there were 6 curves with 3 radius values (i.e., 200, 500, and 800 m) and 2 turning directions (i.e., left and right). Analysis was conducted on driving performance measures such as longitudinal speed, steering wheel movements, and lateral position. RESULTS confirmed that decremental changes in driving performance due to fatigue varied among road conditions. On straight segments, drivers' abilities to steer and maintain lane position were impaired, whereas on curves we found decremental changes in the quality of longitudinal speed as well as steering control and keeping the vehicle in the lane. Moreover, the effects of fatigue on driving performance were relative to the radius and direction of the curve. Fatigue impaired drivers' abilities to control the steering wheel, and the impairment proved more obvious on curves. The degree varied significantly as the curve radius changed. Drivers tended to drive closer to the right side due to fatigue, and the impairment in maintaining lane position became more obvious as the right-turn curve radius decreased. Driver fatigue has detrimental effects on driving performance, and the effects differ under different roadway geometries.

Circuit models and three-dimensional electromagnetic simulations of a 1-MA linear transformer driver stage

NASA Astrophysics Data System (ADS)

Rose, D. V.; Miller, C. L.; Welch, D. R.; Clark, R. E.; Madrid, E. A.; Mostrom, C. B.; Stygar, W. A.; Lechien, K. R.; Mazarakis, M. A.; Langston, W. L.; Porter, J. L.; Woodworth, J. R.

2010-09-01

A 3D fully electromagnetic (EM) model of the principal pulsed-power components of a high-current linear transformer driver (LTD) has been developed. LTD systems are a relatively new modular and compact pulsed-power technology based on high-energy density capacitors and low-inductance switches located within a linear-induction cavity. We model 1-MA, 100-kV, 100-ns rise-time LTD cavities [A. A. Kim , Phys. Rev. ST Accel. Beams 12, 050402 (2009)PRABFM1098-440210.1103/PhysRevSTAB.12.050402] which can be used to drive z-pinch and material dynamics experiments. The model simulates the generation and propagation of electromagnetic power from individual capacitors and triggered gas switches to a radially symmetric output line. Multiple cavities, combined to provide voltage addition, drive a water-filled coaxial transmission line. A 3D fully EM model of a single 1-MA 100-kV LTD cavity driving a simple resistive load is presented and compared to electrical measurements. A new model of the current loss through the ferromagnetic cores is developed for use both in circuit representations of an LTD cavity and in the 3D EM simulations. Good agreement between the measured core current, a simple circuit model, and the 3D simulation model is obtained. A 3D EM model of an idealized ten-cavity LTD accelerator is also developed. The model results demonstrate efficient voltage addition when driving a matched impedance load, in good agreement with an idealized circuit model.

Production of internal transport barriers via self-generated mean flows in Alcator C-Moda)

NASA Astrophysics Data System (ADS)

Fiore, C. L.; Ernst, D. R.; Podpaly, Y. A.; Mikkelsen, D.; Howard, N. T.; Lee, Jungpyo; Reinke, M. L.; Rice, J. E.; Hughes, J. W.; Ma, Y.; Rowan, W. L.; Bespamyatnov, I.

2012-05-01

New results suggest that changes observed in the intrinsic toroidal rotation influence the internal transport barrier (ITB) formation in the Alcator C-Mod tokamak [E. S. Marmar and Alcator C-Mod group, Fusion Sci. Technol. 51, 261 (2007)]. These arise when the resonance for ion cyclotron range of frequencies (ICRF) minority heating is positioned off-axis at or outside of the plasma half-radius. These ITBs form in a reactor relevant regime, without particle or momentum injection, with Ti ≈ Te, and with monotonic q profiles (qmin < 1). C-Mod H-mode plasmas exhibit strong intrinsic co-current rotation that increases with increasing stored energy without external drive. When the resonance position is moved off-axis, the rotation decreases in the center of the plasma resulting in a radial toroidal rotation profile with a central well which deepens and moves farther off-axis when the ICRF resonance location reaches the plasma half-radius. This profile results in strong E × B shear (>1.5 × 105 rad/s) in the region where the ITB foot is observed. Gyrokinetic analyses indicate that this spontaneous shearing rate is comparable to the linear ion temperature gradient (ITG) growth rate at the ITB location and is sufficient to reduce the turbulent particle and energy transport. New and detailed measurement of the ion temperature demonstrates that the radial profile flattens as the ICRF resonance position moves off axis, decreasing the drive for the ITG the instability as well. These results are the first evidence that intrinsic rotation can affect confinement in ITB plasmas.

Continuously-Variable Positive-Mesh Power Transmission

NASA Technical Reports Server (NTRS)

Johnson, J. L.

1982-01-01

Proposed transmission with continuously-variable speed ratio couples two mechanical trigonometric-function generators. Transmission is expected to handle higher loads than conventional variable-pulley drives; and, unlike variable pulley, positive traction through entire drive train with no reliance on friction to transmit power. Able to vary speed continuously through zero and into reverse. Possible applications in instrumentation where drive-train slippage cannot be tolerated.

Lawrence Livermore National Laboratory ULTRA-350 Test Bed

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

Hopkins, D J; Wulff, T A; Carlisle, K

2001-04-10

LLNL has many in-house designed high precision machine tools. Some of these tools include the Large Optics Diamond Turning Machine (LODTM) [1], Diamond Turning Machine No.3 (DTM-3) and two Precision Engineering Research Lathes (PERL-1 and PERL-11). These machines have accuracy in the sub-micron range and in most cases position resolution in the couple of nanometers range. All of these machines are built with similar underlying technologies. The machines use capstan drive technology, laser interferometer position feedback, tachometer velocity feedback, permanent magnet (PM) brush motors and analog velocity and position loop servo compensation [2]. The machine controller does not perform anymore » servo compensation it simply computes the differences between the commanded position and the actual position (the following error) and sends this to a D/A for the analog servo position loop. LLNL is designing a new high precision diamond turning machine. The machine is called the ULTRA 350 [3]. In contrast to many of the proven technologies discussed above, the plan for the new machine is to use brushless linear motors, high precision linear scales, machine controller motor commutation and digital servo compensation for the velocity and position loops. Although none of these technologies are new and have been in use in industry, applications of these technologies to high precision diamond turning is limited. To minimize the risks of these technologies in the new machine design, LLNL has established a test bed to evaluate these technologies for application in high precision diamond turning. The test bed is primarily composed of commercially available components. This includes the slide with opposed hydrostatic bearings, the oil system, the brushless PM linear motor, the two-phase input three-phase output linear motor amplifier and the system controller. The linear scales are not yet commercially available but use a common electronic output format. As of this writing, the final verdict for the use of these technologies is still out but the first part of the work has been completed with promising results. The goal of this part of the work was to close a servo position loop around a slide incorporating these technologies and to measure the performance. This paper discusses the tests that were setup for system evaluation and the results of the measurements made. Some very promising results include; slide positioning to nanometer level and slow speed slide direction reversal at less than 100nm/min with no observed discontinuities. This is very important for machine contouring in diamond turning. As a point of reference, at 100 nm/min it would take the slide almost 7 years to complete the full designed travel of 350 mm. This speed has been demonstrated without the use of a velocity sensor. The velocity is derived from the position sensor. With what has been learned on the test bed, the paper finishes with a brief comparison of the old and new technologies. The emphasis of this comparison will be on the servo performance as illustrated with bode plot diagrams.« less

Lawrence Livermore National Laboratory ULTRA-350 Test Bed

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

Hopkins, D J; Wulff, T A; Carlisle, K

2001-04-10

LLNL has many in-house designed high precision machine tools. Some of these tools include the Large Optics Diamond Turning Machine (LODTM) [1], Diamond Turning Machine No.3 (DTM-3) and two Precision Engineering Research Lathes (PERL-I and PERL-II). These machines have accuracy in the sub-micron range and in most cases position resolution in the couple of nanometers range. All of these machines are built with similar underlying technologies. The machines use capstan drive technology, laser interferometer position feedback, tachometer velocity feedback, permanent magnet (PM) brush motors and analog velocity and position loop servo compensation [2]. The machine controller does not perform anymore » servo compensation it simply computes the differences between the commanded position and the actual position (the following error) and sends this to a D/A for the analog servo position loop. LLNL is designing a new high precision diamond turning machine. The machine is called the ULTRA 350 [3]. In contrast to many of the proven technologies discussed above, the plan for the new machine is to use brushless linear motors, high precision linear scales, machine controller motor commutation and digital servo compensation for the velocity and position loops. Although none of these technologies are new and have been in use in industry, applications of these technologies to high precision diamond turning is limited. To minimize the risks of these technologies in the new machine design, LLNL has established a test bed to evaluate these technologies for application in high precision diamond turning. The test bed is primarily composed of commercially available components. This includes the slide with opposed hydrostatic bearings, the oil system, the brushless PM linear motor, the two-phase input three-phase output linear motor amplifier and the system controller. The linear scales are not yet commercially available but use a common electronic output format. As of this writing, the final verdict for the use of these technologies is still out but the first part of the work has been completed with promising results. The goal of this part of the work was to close a servo position loop around a slide incorporating these technologies and to measure the performance. This paper discusses the tests that were setup for system evaluation and the results of the measurements made. Some very promising results include; slide positioning to nanometer level and slow speed slide direction reversal at less than 100nm/min with no observed discontinuities. This is very important for machine contouring in diamond turning. As a point of reference, at 100 nm/min it would take the slide almost 7 years to complete the full designed travel of 350 mm. This speed has been demonstrated without the use of a velocity sensor. The velocity is derived from the position sensor. With what has been learned on the test bed, the paper finishes with a brief comparison of the old and new technologies. The emphasis of this comparison will be on the servo performance as illustrated with bode plot diagrams.« less

49 CFR 571.201 - Standard No. 201; Occupant protection in interior impact.

Code of Federal Regulations, 2011 CFR

2011-10-01

... seat. Ambulance means a motor vehicle designed exclusively for the purpose of emergency medical care... designated seating position, with adjustable forward seats in their rearmost design driving position and reclinable forward seat backs in their nominal design driving position; (b) Direction of impact shall be...

49 CFR 571.201 - Standard No. 201; Occupant protection in interior impact.

Code of Federal Regulations, 2010 CFR

2010-10-01

... seat. Ambulance means a motor vehicle designed exclusively for the purpose of emergency medical care... designated seating position, with adjustable forward seats in their rearmost design driving position and reclinable forward seat backs in their nominal design driving position; (b) Direction of impact shall be...

Precision magnetic suspension linear bearing

NASA Technical Reports Server (NTRS)

Trumper, David L.; Queen, Michael A.

1992-01-01

We have shown the design and analyzed the electromechanics of a linear motor suitable for independently controlling two suspension degrees of freedom. This motor, at least on paper, meets the requirements for driving an X-Y stage of 10 Kg mass with about 4 m/sq sec acceleration, with travel of several hundred millimeters in X and Y, and with reasonable power dissipation. A conceptual design for such a stage is presented. The theoretical feasibility of linear and planar bearings using single or multiple magnetic suspension linear motors is demonstrated.

Methods, systems and apparatus for adjusting modulation index to improve linearity of phase voltage commands

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

Gallegos-Lopez, Gabriel; Perisic, Milun; Kinoshita, Michael H.

2017-03-14

Embodiments of the present invention relate to methods, systems and apparatus for controlling operation of a multi-phase machine in a motor drive system. The disclosed embodiments provide a mechanism for adjusting modulation index of voltage commands to improve linearity of the voltage commands.

Development and application of a ray-based model of light propagation through a spherical acousto-optic lens

PubMed Central

Evans, Geoffrey J.; Kirkby, Paul A.; Nadella, K. M. Naga Srinivas; Marin, Bóris; Silver, R. Angus

2016-01-01

A spherical acousto-optic lens (AOL) consists of four acousto-optic deflectors (AODs) that can rapidly and precisely control the focal position of an optical beam in 3D space. Development and application of AOLs has increased the speed at which 3D random access point measurements can be performed with a two-photon microscope. This has been particularly useful for measuring brain activity with fluorescent reporter dyes because neuronal signalling is rapid and sparsely distributed in 3D space. However, a theoretical description of light propagation through AOLs has lagged behind their development, resulting in only a handful of simplified principles to guide AOL design and optimization. To address this we have developed a ray-based computer model of an AOL incorporating acousto-optic diffraction and refraction by anisotropic media. We extended an existing model of a single AOD with constant drive frequency to model a spherical AOL: four AODs in series driven with linear chirps. AOL model predictions of the relationship between optical transmission efficiency and acoustic drive frequency including second order diffraction effects closely matched experimental measurements from a 3D two-photon AOL microscope. Moreover, exploration of different AOL drive configurations identified a new simple rule for maximizing the field of view of our compact AOL design. By providing a theoretical basis for understanding optical transmission through spherical AOLs, our open source model is likely to be useful for comparing and improving different AOL designs, as well as identifying the acoustic drive configurations that provide the best transmission performance over the 3D focal region. PMID:26368449

Development and application of a ray-based model of light propagation through a spherical acousto-optic lens.

PubMed

Evans, Geoffrey J; Kirkby, Paul A; Naga Srinivas Nadella, K M; Marin, Bóris; Angus Silver, R

2015-09-07

A spherical acousto-optic lens (AOL) consists of four acousto-optic deflectors (AODs) that can rapidly and precisely control the focal position of an optical beam in 3D space. Development and application of AOLs has increased the speed at which 3D random access point measurements can be performed with a two-photon microscope. This has been particularly useful for measuring brain activity with fluorescent reporter dyes because neuronal signalling is rapid and sparsely distributed in 3D space. However, a theoretical description of light propagation through AOLs has lagged behind their development, resulting in only a handful of simplified principles to guide AOL design and optimization. To address this we have developed a ray-based computer model of an AOL incorporating acousto-optic diffraction and refraction by anisotropic media. We extended an existing model of a single AOD with constant drive frequency to model a spherical AOL: four AODs in series driven with linear chirps. AOL model predictions of the relationship between optical transmission efficiency and acoustic drive frequency including second order diffraction effects closely matched experimental measurements from a 3D two-photon AOL microscope. Moreover, exploration of different AOL drive configurations identified a new simple rule for maximizing the field of view of our compact AOL design. By providing a theoretical basis for understanding optical transmission through spherical AOLs, our open source model is likely to be useful for comparing and improving different AOL designs, as well as identifying the acoustic drive configurations that provide the best transmission performance over the 3D focal region.

Screw-released roller brake

NASA Technical Reports Server (NTRS)

Vranish, John M. (Inventor)

1999-01-01

A screw-released roller brake including an input drive assembly, an output drive assembly, a plurality of locking sprags, a mechanical tripper nut for unlocking the sprags, and a casing therefor. The sprags consist of three dimensional (3-D) sprag members having pairs of contact surface regions which engage respective pairs of contact surface regions included in angular grooves or slots formed in the casing and the output drive assembly. The sprags operate to lock the output drive assembly to the casing to prevent rotation thereof in an idle mode of operation. In a drive mode of operation, the tripper is either self actuated or motor driven and is translated linearly up and down against a spline and at the limit of its travel rotates the sprags which unlock while coupling the input drive assembly to the output drive assembly so as to impart a turning motion thereto in either a clockwise or counterclockwise direction.

Electromechanical millimotor

DOEpatents

Garcia, E.J.; Christenson, T.R.; Polosky, M.A.

1999-06-29

A millimeter-sized machine, including electromagnetic circuits adapted to convert electromagnetic energy to mechanical energy, for engaging and operating external mechanical loads. A plurality of millimeter-sized magnetic actuators operate out of phase with each other to control a plurality of millimeter-sized structural elements to drive an external mechanical load. Each actuator is connected to a link. Each link, in turn, is connected to a drive pinion at another similar pivoting joint. When the magnetic actuators are energized, each drive pinion is then capable of driving a larger output gear in gear-like fashion to produce positive torque about the drive pinion center at all angular positions of the output gear. 29 figs.

Electromechanical millimotor

DOEpatents

Garcia, Ernest J.; Christenson, Todd R.; Polosky, Marc A.

1999-01-01

A millimeter-sized machine, including electromagnetic circuits adapted to convert electromagnetic energy to mechanical energy, for engaging and operating external mechanical loads. A plurality of millimeter-sized magnetic actuators operate out of phase with each other to control a plurality of millimeter-sized structural elements to drive an external mechanical load. Each actuator is connected to a link. Each link, in turn, is connected to a drive pinion at another similar pivoting joint. When the magnetic actuators are energized, each drive pinion is then capable of driving a larger output gear in gear-like fashion to produce positive torque about the drive pinion center at all angular positions of the output gear.

Method And Apparatus For Regenerating Nox Adsorbers

DOEpatents

Driscoll, J. Joshua; Endicott, Dennis L.; Faulkner, Stephen A.; Verkiel, Maarten

2006-03-28

Methods and apparatuses for regenerating a NOx adsorber coupled with an exhaust of an engine. An actuator drives a throttle valve to a first position when regeneration of the NOx adsorber is desired. The first position is a position that causes the regeneration of the NOx adsorber. An actuator drives the throttle valve to a second position while regeneration of the NOx adsorber is still desired. The second position being a position that is more open than the first position and operable to regenerate a NOx adsorber.

Microminiature linear split Stirling cryogenic cooler for portable infrared imagers

NASA Astrophysics Data System (ADS)

Veprik, A.; Vilenchik, H.; Riabzev, S.; Pundak, N.

2007-04-01

Novel tactics employed in carrying out military and antiterrorist operations call for the development of a new generation of warfare, among which sophisticated portable infrared (IR) imagers for surveillance, reconnaissance, targeting and navigation play an important role. The superior performance of such imagers relies on novel optronic technologies and maintaining the infrared focal plane arrays at cryogenic temperatures using closed cycle refrigerators. Traditionally, rotary driven Stirling cryogenic engines are used for this purpose. As compared to their military off-theshelf linear rivals, they are lighter, more compact and normally consume less electrical power. Latest technological advances in industrial development of high-temperature (100K) infrared detectors initialized R&D activity towards developing microminiature cryogenic coolers, both of rotary and linear types. On this occasion, split linearly driven cryogenic coolers appear to be more suitable for the above applications. Their known advantages include flexibility in the system design, inherently longer life time, low vibration export and superior aural stealth. Moreover, recent progress in designing highly efficient "moving magnet" resonant linear drives and driving electronics enable further essential reduction of the cooler size, weight and power consumption. The authors report on the development and project status of a novel Ricor model K527 microminiature split Stirling linear cryogenic cooler designed especially for the portable infrared imagers.

Turbulent current drive mechanisms

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

McDevitt, Christopher J.; Tang, Xian-Zhu; Guo, Zehua

Mechanisms through which plasma microturbulence can drive a mean electron plasma current are derived. The efficiency through which these turbulent contributions can drive deviations from neoclassical predictions of the electron current profile is computed by employing a linearized Coulomb collision operator. It is found that a non-diffusive contribution to the electron momentum flux as well as an anomalous electron-ion momentum exchange term provide the most efficient means through which turbulence can modify the mean electron current for the cases considered. Such turbulent contributions appear as an effective EMF within Ohm’s law, and hence provide an ideal means for driving deviationsmore » from neoclassical predictions.« less

Turbulent current drive mechanisms

DOE PAGES

McDevitt, Christopher J.; Tang, Xian-Zhu; Guo, Zehua

2017-07-01

Mechanisms through which plasma microturbulence can drive a mean electron plasma current are derived. The efficiency through which these turbulent contributions can drive deviations from neoclassical predictions of the electron current profile is computed by employing a linearized Coulomb collision operator. It is found that a non-diffusive contribution to the electron momentum flux as well as an anomalous electron-ion momentum exchange term provide the most efficient means through which turbulence can modify the mean electron current for the cases considered. Such turbulent contributions appear as an effective EMF within Ohm’s law, and hence provide an ideal means for driving deviationsmore » from neoclassical predictions.« less

Time-dependent constitutive modeling of drive belts—II. The effect of the shape of material retardation spectrum on the strain accumulation process

NASA Astrophysics Data System (ADS)

Zupančič, B.; Emri, I.

2009-11-01

This is the second paper in the series addressing the constitutive modeling of dynamically loaded elastomeric products such as power transmission belts. During the normal operation of such belts certain segments of the belt structure are loaded via tooth-like cyclical loading. When the time-dependent properties of the elastomeric material “match” the time-scale of the dynamic loading a strain accumulation (incrementation) process occurs. It was shown that the location of a critical rotation speed strongly depends on the distribution (shape) of the retardation spectrum, whereas the magnitude of the accumulated strain is governed by the strength of the corresponding spectrum lines. These interrelations are extremely non-linear. The strain accumulation process is most intensive at the beginning of the drive belt operation, and is less intensive for longer belts. The strain accumulation process is governed by the spectrum lines that are positioned within a certain region, which we call the Strain Accumulation Window (SAW). An SAW is always located to the right of the spectrum line, L i , at log ( ω λ i )=0, where ω is the operational angular velocity. The width of the SAW depends on the width of the material spectrum. Based on the following analysis a new designing criterion is proposed for use in engineering applications for selecting a proper material for general drive-belt operations.

Conserved interdomain linker promotes phase separation of the multivalent adaptor protein Nck

PubMed Central

Banjade, Sudeep; Wu, Qiong; Mittal, Anuradha; Peeples, William B.; Pappu, Rohit V.; Rosen, Michael K.

2015-01-01

The organization of membranes, the cytosol, and the nucleus of eukaryotic cells can be controlled through phase separation of lipids, proteins, and nucleic acids. Collective interactions of multivalent molecules mediated by modular binding domains can induce gelation and phase separation in several cytosolic and membrane-associated systems. The adaptor protein Nck has three SRC-homology 3 (SH3) domains that bind multiple proline-rich segments in the actin regulatory protein neuronal Wiskott-Aldrich syndrome protein (N-WASP) and an SH2 domain that binds to multiple phosphotyrosine sites in the adhesion protein nephrin, leading to phase separation. Here, we show that the 50-residue linker between the first two SH3 domains of Nck enhances phase separation of Nck/N-WASP/nephrin assemblies. Two linear motifs within this element, as well as its overall positively charged character, are important for this effect. The linker increases the driving force for self-assembly of Nck, likely through weak interactions with the second SH3 domain, and this effect appears to promote phase separation. The linker sequence is highly conserved, suggesting that the sequence determinants of the driving forces for phase separation may be generally important to Nck functions. Our studies demonstrate that linker regions between modular domains can contribute to the driving forces for self-assembly and phase separation of multivalent proteins. PMID:26553976

Fourier-domain study of drift turbulence driven sheared flow in a laboratory plasma

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

Xu, M.; Tynan, G. R.; Holland, C.

2010-03-15

Frequency-resolved nonlinear internal and kinetic energy transfer rates have been measured in the Controlled Shear Decorrelation Experiment (CSDX) linear plasma device using a recently developed technique [Xu et al., Phys. Plasmas 16, 042312 (2009)]. The results clearly show a net kinetic energy transfer into the zonal flow frequency region, consistent with previous time-domain observations of turbulence-driven shear flows [Tynan et al., Plasma Phys. Controlled Fusion 48, S51 (2006)]. The experimentally measured dispersion relation has been used to map the frequency-resolved energy transfer rates into the wave number domain, which shows that the shear flow drive comes from midrange (k{sub t}hetarho{submore » S}>0.3) drift fluctuations, and the strongest flow drive comes from k{sub t}hetarho{sub S}approx =1 fluctuations. Linear growth rates have been inferred from a linearized Hasegawa-Wakatani model [Hasegawa et al., Phys. Fluids 22, 2122 (1979)], which indicates that the m=0 mode is linearly stable and the m=1-10 modes (corresponding to k{sub t}hetarho{sub S}>0.3) are linearly unstable for the n=1 and n=2 radial eigenmodes. This is consistent with our energy transfer measurements.« less

Nuclear reactor remote disconnect control rod coupling indicator

DOEpatents

Vuckovich, Michael

1977-01-01

A coupling indicator for use with nuclear reactor control rod assemblies which have remotely disengageable couplings between the control rod and the control rod drive shaft. The coupling indicator indicates whether the control rod and the control rod drive shaft are engaged or disengaged. A resistive network, utilizing magnetic reed switches, senses the position of the control rod drive mechanism lead screw and the control rod position indicating tube, and the relative position of these two elements with respect to each other is compared to determine whether the coupling is engaged or disengaged.

Design and fabrication of a long-life Stirling cycle cooler for space application. Phase 3: Prototype model. Final Report, Sep. 1981 - Sep. 1990

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

Keung, C.; Patt, P.J.; Starr, M.

A second-generation, Stirling-cycle cryocooler (cryogenic refrigerator) for space applications, with a cooling capacity of 5 watts at 65 K, was recently completed. The refrigerator, called the Prototype Model, was designed with a goal of 5 year life with no degradation in cooling performance. The free displacer and free piston of the refrigerator are driven directly by moving-magnet linear motors with the moving elements supported by active magnetic bearings. The use of clearance seals and the absence of outgassing material in the working volume of the refrigerator enable long-life operation with no deterioration in performance. Fiber-optic sensors detect the radial positionmore » of the shafts and provide a control signal for the magnetic bearings. The frequency, phase, stroke, and offset of the compressor and expander are controlled by signals from precision linear position sensors (LVDTs). The vibration generated by the compressor and expander is cancelled by an active counter balance which also uses a moving-magnet linear motor and magnetic bearings. The driving signal for the counter balance is derived from the compressor and expander position sensors which have wide bandwidth for suppression of harmonic vibrations. The efficiency of the three active members, which operate in a resonant mode, is enhanced by a magnetic spring in the expander and by gas springs in the compressor and counterbalance. The cooling was achieved with a total motor input power of 139 watts. The magnetic-bearing stiffness was significantly increased from the first-generation cooler to accommodate shuttle launch vibrations.« less

Research of subdivision driving technology for brushless DC motors in optical fiber positioning

NASA Astrophysics Data System (ADS)

Kan, Yi; Gu, Yonggang; Zhu, Ye; Zhai, Chao

2016-07-01

In fiber spectroscopic telescopes, optical fiber positioning units are used to position thousands of fibers on the focal plane quickly and precisely. Stepper motors are used in existing units, however, it has some inherent deficiencies, such as serious heating and low efficiency. In this work, the universally adopted subdivision driving technology for stepper motors is transplanted to brushless DC motors. It keeps the advantages of stepper motors such as high positioning accuracy and resolution, while overcomes the disadvantages mentioned above. Thus, this research mainly focuses on develop a novel subdivision driving technology for brushless DC motor. By the proving of experiments of online debug and subdivision speed and position, the proposed brushless DC motor subdivision technology can achieve the expected functions.

Firing-rate response of linear and nonlinear integrate-and-fire neurons to modulated current-based and conductance-based synaptic drive.

PubMed

Richardson, Magnus J E

2007-08-01

Integrate-and-fire models are mainstays of the study of single-neuron response properties and emergent states of recurrent networks of spiking neurons. They also provide an analytical base for perturbative approaches that treat important biological details, such as synaptic filtering, synaptic conductance increase, and voltage-activated currents. Steady-state firing rates of both linear and nonlinear integrate-and-fire models, receiving fluctuating synaptic drive, can be calculated from the time-independent Fokker-Planck equation. The dynamic firing-rate response is less easy to extract, even at the first-order level of a weak modulation of the model parameters, but is an important determinant of neuronal response and network stability. For the linear integrate-and-fire model the response to modulations of current-based synaptic drive can be written in terms of hypergeometric functions. For the nonlinear exponential and quadratic models no such analytical forms for the response are available. Here it is demonstrated that a rather simple numerical method can be used to obtain the steady-state and dynamic response for both linear and nonlinear models to parameter modulation in the presence of current-based or conductance-based synaptic fluctuations. To complement the full numerical solution, generalized analytical forms for the high-frequency response are provided. A special case is also identified--time-constant modulation--for which the response to an arbitrarily strong modulation can be calculated exactly.

Linear theory on temporal instability of megahertz faraday waves for monodisperse microdroplet ejection.

PubMed

Tsai, Shirley C; Tsai, Chen S

2013-08-01

A linear theory on temporal instability of megahertz Faraday waves for monodisperse microdroplet ejection based on mass conservation and linearized Navier-Stokes equations is presented using the most recently observed micrometer- sized droplet ejection from a millimeter-sized spherical water ball as a specific example. The theory is verified in the experiments utilizing silicon-based multiple-Fourier horn ultrasonic nozzles at megahertz frequency to facilitate temporal instability of the Faraday waves. Specifically, the linear theory not only correctly predicted the Faraday wave frequency and onset threshold of Faraday instability, the effect of viscosity, the dynamics of droplet ejection, but also established the first theoretical formula for the size of the ejected droplets, namely, the droplet diameter equals four-tenths of the Faraday wavelength involved. The high rate of increase in Faraday wave amplitude at megahertz drive frequency subsequent to onset threshold, together with enhanced excitation displacement on the nozzle end face, facilitated by the megahertz multiple Fourier horns in resonance, led to high-rate ejection of micrometer- sized monodisperse droplets (>10(7) droplets/s) at low electrical drive power (<;1 W) with short initiation time (<;0.05 s). This is in stark contrast to the Rayleigh-Plateau instability of a liquid jet, which ejects one droplet at a time. The measured diameters of the droplets ranging from 2.2 to 4.6 μm at 2 to 1 MHz drive frequency fall within the optimum particle size range for pulmonary drug delivery.

Shortcuts to adiabaticity from linear response theory

DOE PAGES

Acconcia, Thiago V.; Bonança, Marcus V. S.; Deffner, Sebastian

2015-10-23

A shortcut to adiabaticity is a finite-time process that produces the same final state as would result from infinitely slow driving. We show that such shortcuts can be found for weak perturbations from linear response theory. Moreover, with the help of phenomenological response functions, a simple expression for the excess work is found—quantifying the nonequilibrium excitations. For two specific examples, i.e., the quantum parametric oscillator and the spin 1/2 in a time-dependent magnetic field, we show that finite-time zeros of the excess work indicate the existence of shortcuts. We finally propose a degenerate family of protocols, which facilitates shortcuts tomore » adiabaticity for specific and very short driving times.« less

Spine-fan reconnection. The influence of temporal and spatial variation in the driver

NASA Astrophysics Data System (ADS)

Wyper, P. F.; Jain, R.; Pontin, D. I.

2012-09-01

Context. From observations, the atmosphere of the Sun has been shown to be highly dynamic with perturbations of the magnetic field often lacking temporal or spatial symmetry. Despite this, studies of the spine-fan reconnection mode at 3D nulls have so far focused on the very idealised case with symmetric driving of a fixed spatial extent. Aims: We investigate the spine-fan reconnection process for less idealised cases, focusing on asymmetric driving and drivers with different length scales. We look at the initial current sheet formation and whether the scalings developed in the idealised models are robust in more realistic situations. Methods: The investigation was carried out by numerically solving the resistive compressible 3D magnetohydrodynamic equations in a Cartesian box containing a linear null point. The spine-fan collapse was driven at the null through tangential boundary driving of the spine foot points. Results: We find significant differences in the initial current sheet formation with asymmetric driving. Notable is the displacement of the null point position as a function of driving velocity and resistivity (η). However, the scaling relations developed in the idealised case are found to be robust (albeit at reduced amplitudes) despite this extra complexity. Lastly, the spatial variation is also shown to play an important role in the initial current sheet formation through controlling the displacement of the spine foot points. Conclusions: We conclude that during the early stages of spine-fan reconnection both the temporal and spatial nature of the driving play important roles, with the idealised symmetrically driven case giving a "best case" for the rate of current development and connectivity change. As the most interesting eruptive events occur in relatively short time frames this work clearly shows the need for high temporal and spatial knowledge of the flows for accurate interpretation of the reconnection scenario. Lastly, since the scalings developed in the idealised case remain robust with more complex driving we can be more confident of their use in interpreting reconnection in complex magnetic field structures.

Sensor-less pseudo-sinusoidal drive for a permanent-magnet brushless ac motor

NASA Astrophysics Data System (ADS)

Liu, Li-Hsiang; Chern, Tzuen-Lih; Pan, Ping-Lung; Huang, Tsung-Mou; Tsay, Der-Min; Kuang, Jao-Hwa

2012-04-01

The precise rotor-position information is required for a permanent-magnet brushless ac motor (BLACM) drive. In the conventional sinusoidal drive method, either an encoder or a resolver is usually employed. For position sensor-less vector control schemes, the rotor flux estimation and torque components are obtained by complicated coordinate transformations. These computational intensive methods are susceptible to current distortions and parameter variations. To simplify the method complexity, this work presents a sensor-less pseudo-sinusoidal drive scheme with speed control for a three-phase BLACM. Based on the sinusoidal drive scheme, a floating period of each phase current is inserted for back electromotive force detection. The zero-crossing point is determined directly by the proposed scheme, and the rotor magnetic position and rotor speed can be estimated simultaneously. Several experiments for various active angle periods are undertaken. Furthermore, a current feedback control is included to minimize and compensate the torque fluctuation. The experimental results show that the proposed method has a competitive performance compared with the conventional drive manners for BLACM. The proposed scheme is straightforward, bringing the benefits of sensor-less drive and negating the need for coordinate transformations in the operating process.

Measuring Risky Driving Behavior Using an mHealth Smartphone App: Development and Evaluation of gForce.

PubMed

Freidlin, Raisa Z; Dave, Amisha D; Espey, Benjamin G; Stanley, Sean T; Garmendia, Marcial A; Pursley, Randall; Ehsani, Johnathon P; Simons-Morton, Bruce G; Pohida, Thomas J

2018-04-19

Naturalistic driving studies, designed to objectively assess driving behavior and outcomes, are conducted by equipping vehicles with dedicated instrumentation (eg, accelerometers, gyroscopes, Global Positioning System, and cameras) that provide continuous recording of acceleration, location, videos, and still images for eventual retrieval and analyses. However, this research is limited by several factors: the cost of equipment installation; management and storage of the large amounts of data collected; and data reduction, coding, and analyses. Modern smartphone technology includes accelerometers built into phones, and the vast, global proliferation of smartphones could provide a possible low-cost alternative for assessing kinematic risky driving. We evaluated an in-house developed iPhone app (gForce) for detecting elevated g-force events by comparing the iPhone linear acceleration measurements with corresponding acceleration measurements obtained with both a custom Android app and the in-vehicle miniDAS data acquisition system (DAS; Virginia Tech Transportation Institute). The iPhone and Android devices were dashboard-mounted in a vehicle equipped with the DAS instrumentation. The experimental protocol consisted of driving maneuvers on a test track, such as cornering, braking, and turning that were performed at different acceleration levels (ie, mild, moderate, or hard). The iPhone gForce app recorded linear acceleration (ie, gravity-corrected). The Android app recorded gravity-corrected and uncorrected acceleration measurements, and the DAS device recorded gravity-uncorrected acceleration measurements. Lateral and longitudinal acceleration measures were compared. The correlation coefficients between the iPhone and DAS acceleration measurements were slightly lower compared to the correlation coefficients between the Android and DAS, possibly due to the gravity correction on the iPhone. Averaging the correlation coefficients for all maneuvers, the longitudinal and lateral acceleration measurements between iPhone and DAS were r lng =0.71 and r lat =0.83, respectively, while the corresponding acceleration measurements between Android and DAS were r lng =0.95 and r lat =0.97. The correlation coefficients between lateral accelerations on all three devices were higher than with the corresponding longitudinal accelerations for most maneuvers. The gForce iPhone app reliably assessed elevated g-force events compared to the DAS. Collectively, the gForce app and iPhone platform have the potential to serve as feature-rich, inexpensive, scalable, and open-source tool for assessment of kinematic risky driving events, with potential for research and feedback forms of intervention. ©Raisa Z Freidlin, Amisha D Dave, Benjamin G Espey, Sean T Stanley, Marcial A Garmendia, Randall Pursley, Johnathon P Ehsani, Bruce G Simons-Morton, Thomas J Pohida. Originally published in JMIR Mhealth and Uhealth (http://mhealth.jmir.org), 19.04.2018.

Oscillatory instability of a self-rewetting film driven by thermal modulation

NASA Astrophysics Data System (ADS)

Batson, William; Agnon, Yehuda; Oron, Alex

2016-11-01

Here we consider the self-rewetting fluids (SRWFs) that exhibit a well-defined minimum surface tension with respect to temperature, in contrast to those where surface tension decreases linearly. Utilization of SRWFs has grown significantly in the past decade, due to observations that heat transfer is enhanced in applications such as film boiling and pulsating heat pipes. With similar applications in mind, we investigate the dynamics of a thin SRWF film which is subjected to a temperature modulation in the bounding gas. A model is developed within the framework of the long-wave approximation, and a time-averaged thermocapillary driving force for destabilization is uncovered for SRWFs that results from the nonlinear surface tension. Linear analysis of the nonlinear PDE for the film thickness is used to determine the critical conditions at which this driving force destabilizes the film, and, numerical integration of this evolution equation reveals that linearly unstable perturbations saturate to regular periodic solutions (when the modulational frequency is set properly). Properties of these flows such as bifurcation and long-domain flows, where multiple unstable linear modes interact, will also be discussed.

Chain friction system gives positive, reversible drive

NASA Technical Reports Server (NTRS)

Davidsen, J. S.

1964-01-01

By cementing a strip of an elastomer to the smooth metal rim of the pulley and neoprene covered idlers providing suitable tension to the chain around the pulley, a positive reversible drive is accomplished more quietly and with less vibration.

Indirect rotor position sensing in real time for brushless permanent magnet motor drives

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

Ertugrul, N.; Acarnley, P.P.

1998-07-01

This paper describes a modern solution to real-time rotor position estimation of brushless permanent magnet (PM) motor drives. The position estimation scheme, based on flux linkage and line-current estimation, is implemented in real time by using the abc reference frame, and it is tested dynamically. The position estimation model of the test motor, development of hardware, and basic operation of the digital signal processor (DSP) are discussed. The overall position estimation strategy is accomplished with a fast DSP (TMS320C30). The method is a shaft position sensorless method that is applicable to a wide range of excitation types in brushless PMmore » motors without any restriction on the motor model and the current excitation. Both rectangular and sinewave-excited brushless PM motor drives are examined, and the results are given to demonstrate the effectiveness of the method with dynamic loads in closed estimated position loop.« less

Dimensions of driving anger and their relationships with aberrant driving.

PubMed

Zhang, Tingru; Chan, Alan H S; Zhang, Wei

2015-08-01

The purpose of this study was to investigate the relationship between driving anger and aberrant driving behaviours. An internet-based questionnaire survey was administered to a sample of Chinese drivers, with driving anger measured by a 14-item short Driving Anger Scale (DAS) and the aberrant driving behaviours measured by a 23-item Driver Behaviour Questionnaire (DBQ). The results of Confirmatory Factor Analysis demonstrated that the three-factor model (hostile gesture, arrival-blocking and safety-blocking) of the DAS fitted the driving anger data well. The Exploratory Factor Analysis on DBQ data differentiated four types of aberrant driving, viz. emotional violation, error, deliberate violation and maintaining progress violation. For the anger-aberration relation, it was found that only "arrival-blocking" anger was a significant positive predictor for all four types of aberrant driving behaviours. The "safety-blocking" anger revealed a negative impact on deliberate violations, a finding different from previously established positive anger-aberration relation. These results suggest that drivers with different patterns of driving anger would show different behavioural tendencies and as a result intervention strategies may be differentially effective for drivers of different profiles. Copyright © 2015 Elsevier Ltd. All rights reserved.

Calculation and manipulation of the chirp rates of high-order harmonics

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

Murakami, M.; Mauritsson, J.; Schafer, K.J.

2005-01-01

We calculate the linear chirp rates of high-order harmonics in argon, generated by intense, 810 nm laser pulses, and explore the dependence of the chirp rate on harmonic order, driving laser intensity, and pulse duration. By using a time-frequency representation of the harmonic fields we can identify several different linear chirp contributions to the plateau harmonics. Our results, which are based on numerical integration of the time-dependent Schroedinger equation, are in good agreement with the adiabatic predictions of the strong field approximation for the chirp rates. Extending the theoretical analysis in the recent paper by Mauritsson et al. [Phys. Rev.more » A 70, 021801(R) (2004)], we also manipulate the chirp rates of the harmonics by adding a chirp to the driving pulse. We show that the chirp rate for harmonic q is given by the sum of the intrinsic chirp rate, which is determined by the new duration and peak intensity of the chirped driving pulse, and q times the external chirp rate.« less

Transport properties of elastically coupled fractional Brownian motors

NASA Astrophysics Data System (ADS)

Lv, Wangyong; Wang, Huiqi; Lin, Lifeng; Wang, Fei; Zhong, Suchuan

2015-11-01

Under the background of anomalous diffusion, which is characterized by the sub-linear or super-linear mean-square displacement in time, we proposed the coupled fractional Brownian motors, in which the asymmetrical periodic potential as ratchet is coupled mutually with elastic springs, and the driving source is the external harmonic force and internal thermal fluctuations. The transport mechanism of coupled particles in the overdamped limit is investigated as the function of the temperature of baths, coupling constant and natural length of the spring, the amplitude and frequency of driving force, and the asymmetry of ratchet potential by numerical stimulations. The results indicate that the damping force involving the information of historical velocity leads to the nonlocal memory property and blocks the traditional dissipative motion behaviors, and it even plays a cooperative role of driving force in drift motion of the coupled particles. Thus, we observe various non-monotonic resonance-like behaviors of collective directed transport in the mediums with different diffusion exponents.

Bio-inspired piezoelectric linear motor driven by a single-phase harmonic wave with an asymmetric stator.

PubMed

Pan, Qiaosheng; Miao, Enming; Wu, Bingxuan; Chen, Weikang; Lei, Xiujun; He, Liangguo

2017-07-01

A novel, bio-inspired, single-phase driven piezoelectric linear motor (PLM) using an asymmetric stator was designed, fabricated, and tested to avoid mode degeneracy and to simplify the drive mechanism of a piezoelectric motor. A piezoelectric transducer composed of two piezoelectric stacks and a displacement amplifier was used as the driving element of the PLM. Two simple and specially designed claws performed elliptical motion. A numerical simulation was performed to design the stator and determine the feasibility of the design mechanism of the PLM. Moreover, an experimental setup was built to validate the working principles, as well as to evaluate the performance, of the PLM. The prototype motor outputs a no-load speed of 233.7 mm/s at a voltage of 180 V p-p and a maximum thrust force of 2.3 N under a preload of 10 N. This study verified the feasibility of the proposed design and provided a method to simplify the driving harmonic signal and structure of PLMs.

Simulating energy cascade of shock wave formation process in a resonator by gas kinetic scheme

NASA Astrophysics Data System (ADS)

Qu, Chengwu; Zhang, Xiaoqing; Feng, Heying

2017-12-01

The temporal-spatial evolution of gas oscillation was simulated by gas kinetic scheme (GKS) in a cylindrical resonator, driven by a piston at one end and rigidly closed at the other end. Periodic shock waves propagating back and forth were observed in the resonator under finite amplitude of gas oscillation. The studied results demonstrated that the acoustic pressure is a saw-tooth waveform and the oscillatory velocity is a square waveform at the central position of the resonant tube. Moreover, it was found by harmonic analysis that there was no presence of obvious feature for pressure node in such a typical standing wave resonator, and the distribution of acoustic fields displayed a one-dimensional feature for the acoustic pressure while a quasi-one-dimensional form for oscillatory velocity, which demonstrated the nonlinear effects. The simulation results for axial distribution of acoustic intensity showed a good consistency with the published experimental data in the open literature domain, which provides a verification for the effectiveness of the GKS model proposed. The influence of displacement amplitude of the driving piston on the formation of shock wave was numerically investigated, and the simulated results revealed the cascade process of harmonic wave energy from the fundamental wave to higher harmonics. In addition, this study found that the acoustic intensity at the driving end of the resonant tube would increase linearly with the displacement amplitude of the piston due to nonlinear effects, rather than the exponential variation by linear theory. This research demonstrates that the GKS model is strongly capable of simulating nonlinear acoustic problems.

Universal power transistor base drive control unit

DOEpatents

Gale, Allan R.; Gritter, David J.

1988-01-01

A saturation condition regulator system for a power transistor which achieves the regulation objectives of a Baker clamp but without dumping excess base drive current into the transistor output circuit. The base drive current of the transistor is sensed and used through an active feedback circuit to produce an error signal which modulates the base drive current through a linearly operating FET. The collector base voltage of the power transistor is independently monitored to develop a second error signal which is also used to regulate base drive current. The current-sensitive circuit operates as a limiter. In addition, a fail-safe timing circuit is disclosed which automatically resets to a turn OFF condition in the event the transistor does not turn ON within a predetermined time after the input signal transition.

Universal power transistor base drive control unit

DOEpatents

Gale, A.R.; Gritter, D.J.

1988-06-07

A saturation condition regulator system for a power transistor is disclosed which achieves the regulation objectives of a Baker clamp but without dumping excess base drive current into the transistor output circuit. The base drive current of the transistor is sensed and used through an active feedback circuit to produce an error signal which modulates the base drive current through a linearly operating FET. The collector base voltage of the power transistor is independently monitored to develop a second error signal which is also used to regulate base drive current. The current-sensitive circuit operates as a limiter. In addition, a fail-safe timing circuit is disclosed which automatically resets to a turn OFF condition in the event the transistor does not turn ON within a predetermined time after the input signal transition. 2 figs.

Association between unsafe driving performance and cognitive-perceptual dysfunction in older drivers.

PubMed

Park, Si-Woon; Choi, Eun Seok; Lim, Mun Hee; Kim, Eun Joo; Hwang, Sung Il; Choi, Kyung-In; Yoo, Hyun-Chul; Lee, Kuem Ju; Jung, Hi-Eun

2011-03-01

To find an association between cognitive-perceptual problems of older drivers and unsafe driving performance during simulated automobile driving in a virtual environment. Cross-sectional study. A driver evaluation clinic in a rehabilitation hospital. Fifty-five drivers aged 65 years or older and 48 drivers in their late twenties to early forties. All participants underwent evaluation of cognitive-perceptual function and driving performance, and the results were compared between older and younger drivers. The association between cognitive-perceptual function and driving performance was analyzed. Cognitive-perceptual function was evaluated with the Cognitive Perceptual Assessment for Driving (CPAD), a computer-based assessment tool consisting of depth perception, sustained attention, divided attention, the Stroop test, the digit span test, field dependency, and trail-making test A and B. Driving performance was evaluated with use of a virtual reality-based driving simulator. During simulated driving, car crashes were recorded, and an occupational therapist observed unsafe performances in controlling speed, braking, steering, vehicle positioning, making lane changes, and making turns. Thirty-five older drivers did not pass the CPAD test, whereas all of the younger drivers passed the test. When using the driving simulator, a significantly greater number of older drivers experienced car crashes and demonstrated unsafe performance in controlling speed, steering, and making lane changes. CPAD results were associated with car crashes, steering, vehicle positioning, and making lane changes. Older drivers who did not pass the CPAD test are 4 times more likely to experience a car crash, 3.5 times more likely to make errors in steering, 2.8 times more likely to make errors in vehicle positioning, and 6.5 times more likely to make errors in lane changes than are drivers who passed the CPAD test. Unsafe driving performance and car crashes during simulated driving were more prevalent in older drivers than in younger drivers. Unsafe performance in steering, vehicle positioning, making lane changes, and car crashes were associated with cognitive-perceptual dysfunction. Copyright © 2011 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

A one-step extraction procedure for the screening of cocaine, amphetamines and cannabinoids in postmortem blood samples.

PubMed

Pelição, Fabrício Souza; Peres, Mariana Dadalto; Pissinate, Jauber Fornaciari; De Martinis, Bruno Spinosa

2014-01-01

A gas chromatography-mass spectrometric (GC-MS) method was developed and validated for the simultaneous detection and quantification in postmortem whole blood samples of cocaine (COC), amphetamines (AMPs) and cannabis; the main drugs involved in cases of impaired driving in Brazil. The analytes were extracted by solid-phase extraction by means of Bond-Elute Certify cartridges, derivatized with N-methyl-N-(trimethylsilyl)trifluoroacetamide at 80°C for 30 min and analyzed by GC-MS. Linearity ranged from 10 to 500 ng/mL, except for ecgonine methyl ester, for which linearity ranged from 10 to 100 ng/mL. Inter- and intra-day imprecision ranged from 2.8 to 18.4% and from 1.5 to 14.9%, respectively. Accuracy values lay between 86.9 and 104.4%. The limit of quantitation for all drugs was 10 ng/mL and recoveries were >74% for all analytes, except for cannabinoids, which showed poor recovery (∼30%). The developed method was applied to real samples collected from deceased victims due to traffic accidents. These samples were selected according to the results obtained in immunoassay screening on collected urine samples. Five samples were positive for the presence of COC and metabolites, four samples were positive for cannabinoids, six samples were positive for AMPs and two samples were drug negative. Some samples were positive for more than one class of drug. Results obtained from whole blood samples showed good agreement with urine screening. The developed method proved capable of quantifying all three classes of drugs of abuse proposed in this study, through a one-step extraction procedure. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Opposed piston linear compressor driven two-stage Stirling Cryocooler for cooling of IR sensors in space application

NASA Astrophysics Data System (ADS)

Bhojwani, Virendra; Inamdar, Asif; Lele, Mandar; Tendolkar, Mandar; Atrey, Milind; Bapat, Shridhar; Narayankhedkar, Kisan

2017-04-01

A two-stage Stirling Cryocooler has been developed and tested for cooling IR sensors in space application. The concept uses an opposed piston linear compressor to drive the two-stage Stirling expander. The configuration used a moving coil linear motor for the compressor as well as for the expander unit. Electrical phase difference of 80 degrees was maintained between the voltage waveforms supplied to the compressor motor and expander motor. The piston and displacer surface were coated with Rulon an anti-friction material to ensure oil less operation of the unit. The present article discusses analysis results, features of the cryocooler and experimental tests conducted on the developed unit. The two-stages of Cryo-cylinder and the expander units were manufactured from a single piece to ensure precise alignment between the two-stages. Flexure bearings were used to suspend the piston and displacer about its mean position. The objective of the work was to develop a two-stage Stirling cryocooler with 2 W at 120 K and 0.5 W at 60 K cooling capacity for the two-stages and input power of less than 120 W. The Cryocooler achieved a minimum temperature of 40.7 K at stage 2.

Miniature cryocooler developments for high operating temperatures at Thales Cryogenics

NASA Astrophysics Data System (ADS)

Arts, R.; Martin, J.-Y.; Willems, D.; Seguineau, C.; Van Acker, S.; Mullié, J. C.; Göbel, A.; Tops, M.; Le Bordays, J.; Etchanchu, T.; Benschop, A. A. J.

2015-05-01

In recent years there has been a drive towards miniaturized cooled IDCA solutions for low-power, low-mass, low-size products (SWaP). To support this drive, coolers are developed optimized for high-temperature, low heat load dewar-detector assemblies. In this paper, Thales Cryogenics development activities supporting SWaP are presented. Design choices are discussed and compared to various key requirements. Trade-off analysis results are presented on drive voltage, cold finger definition (length, material, diameter and sealing concept), and other interface considerations, including cold finger definition. In parallel with linear and rotary cooler options, designs for small-size high-efficiency drive electronics based on state-of-the-art architectures are presented.

Vehicle Dynamics Control of In-wheel Electric Motor Drive Vehicles Based on Averaging of Tire Force Usage

NASA Astrophysics Data System (ADS)

Masaki, Nobuo; Iwano, Haruo; Kamada, Takayoshi; Nagai, Masao

For in-wheel electric motor drive vehicles, a new vehicle dynamics control which is based on the tire force usage rate is proposed. The new controller adopts non-linear optimal control could manage the interference between direct yaw-moment control and the tire force usage rate. The new control is considered total longitudinal and transverse tire force. Therefore the controller can prevent tire force saturation near tire force limit during cornering. Simulations and test runs by the custom made four wheel drive in-wheel motor electric vehicle show that higher driving stability performance compared to the performance of the same vehicle without control.

CAEP position statement on cellphone use while driving.

PubMed

Huang, Dayan; Kapur, Atul K; Ling, Patrick; Purssell, Roy; Henneberry, Ryan J; Champagne, Chantelle R; Lee, Victoria K; Francescutti, Louis H

2010-07-01

Distracted driving caused by cellphone use is a significant source of needless injuries. These injuries place unnecessary financial burden, emotional stress and health care resource misuse on society. This paper states the Canadian Association of Emergency Physician's (CAEP's) position on cellphone use while driving. In recent years, numerous studies were conducted on the danger of cellphone use while driving. Research has shown that cellphone use while driving negatively impacts cognitive functions, visual fields, reaction time and overall driving performances. Some studies found that cellphone use is as dangerous as driving under the influence of alcohol. Moreover, vehicle crash rates were shown to be significantly higher when drivers used cellphones. Countermeasures have been implemented in recent years. Over 50 countries worldwide have laws limiting the use of cellphones while driving. Six Canadian provinces, Newfoundland and Labrador, Nova Scotia, Quebec, Ontario, British Columbia and Saskatchewan, currently have legislation prohibiting cellphone use. Other provinces are considering implementing similar bans. As emergency physicians, we must advocate for injury prevention. Cell phone related road traumas are avoidable. CAEP supports all measures to ban cellphone use while driving.

Energy dynamics in a simulation of LAPD turbulence

NASA Astrophysics Data System (ADS)

Friedman, Brett

2012-10-01

It is often assumed that linear instabilities maintain turbulence in plasmas and some fluids, but this is not always the case. It is well known that many fluids display subcritical turbulence at a Reynolds number well below the threashold of linear instability. Certain plasma models such as drift waves in a sheared slab also exhibit subcritical turbulence [1]. In other instances such as drift-ballooning turbulence in tokamak edge plasmas, linear instabilities exist in a system, but they become subdominant to more robust nonlinear mechanisms that sustain a turbulent state [2, 3]. In our simulation of LAPD turbulence, which was previously analyzed in [4], we diagnose the results using an energy dynamics analysis [5]. This allows us to track energy input into turbulent fluctuations and energy dissipation out of them. We also track conservative energy transfer between different energy types (e.g. from potential to kinetic energy) and between different Fourier waves of the system. The result is that a nonlinear instability drives and maintains the turbulence in the steady state saturated phase of the simulation. While a linear restistive drift wave instability resides in the system, the nonlinear drift wave instability dominates when the fluctuation amplitude becomes large enough. The nonlinear instability is identified by its energy growth rate spectrum, which varies significantly from the linear growth rate spectrum. The main differences are the presence of positive growth rates when k|| = 0 and negative growth rates for nonzero k||, which is opposite that of the linear growth rate spectrum.[4pt] [1] B. D. Scott, Phys. Rev. Lett., 65, 3289 (1990).[0pt] [2] A. Zeiler et al, Phys. Plasmas, 3, 2951 (1996).[0pt] [3] B. D. Scott, Phys. Plasmas, 12, 062314 (2005).[0pt] [4] P. Popovich et al, Phys. Plasmas, 17, 122312 (2010).[0pt] [5] [physics.plasm-ph].

Entropic organization of interphase chromosomes

PubMed Central

Marenduzzo, Davide

2009-01-01

Chromosomes are not distributed randomly in nuclei. Appropriate positioning can activate (or repress) genes by bringing them closer to active (or inactive) compartments like euchromatin (or heterochromatin), and this is usually assumed to be driven by specific local forces (e.g., involving H bonds between nucleosomes or between nucleosomes and the lamina). Using Monte Carlo simulations, we demonstrate that nonspecific (entropic) forces acting alone are sufficient to position and shape self-avoiding polymers within a confining sphere in the ways seen in nuclei. We suggest that they can drive long flexible polymers (representing gene-rich chromosomes) to the interior, compact/thick ones (and heterochromatin) to the periphery, looped (but not linear) ones into appropriately shaped (ellipsoidal) territories, and polymers with large terminal beads (representing centromeric heterochromatin) into peripheral chromocenters. Flexible polymers tend to intermingle less than others, which is in accord with observations that gene-dense (and so flexible) chromosomes make poor translocation partners. Thus, entropic forces probably participate in the self-organization of chromosomes within nuclei. PMID:19752020

Proposition for sensorless self-excitation by a piezoelectric device

NASA Astrophysics Data System (ADS)

Tanaka, Y.; Kokubun, Y.; Yabuno, H.

2018-04-01

In this paper, we propose a method to realize self-excitation in an oscillator actuated by a piezoelectric device without a sensor. In general, the positive feedback associated with the oscillator velocity causes the self-excitation. Instead of measuring the velocity with a sensor, we utilize the electro-mechanical coupling effect in the oscillator and piezoelectric device. We drive the piezoelectric device with a current proportional to the linear combination of the voltage across the terminals of the piezoelectric device and its differential voltage signal. Then, the oscillator with the piezoelectric device behaves like a third-order system, which has three eigenvalues. The self-excitation can be realized because appropriate feedback gains can set two of the eigenvalues to be conjugate complex roots with a positive real part and the other eigenvalue to be a negative real root. To confirm the validity of the proposed method, we experimentally demonstrated the sensorless self-excitation and, as an application example, carried out mass sensing in a sensorless self-excited macrocantilever.

Effects of Alcohol on Performance on a Distraction Task During Simulated Driving

PubMed Central

Allen, Allyssa J.; Meda, Shashwath A.; Skudlarski, Pawel; Calhoun, Vince; Astur, Robert; Ruopp, Kathryn C.; Pearlson, Godfrey D.

2009-01-01

Background Prior studies report that accidents involving intoxicated drivers are more likely to occur during performance of secondary tasks. We studied this phenomenon, using a dual-task paradigm, involving performance of a visual oddball (VO) task while driving in an alcohol challenge paradigm. Previous functional MRI (fMRI) studies of the VO task have shown activation in the anterior cingulate, hippocampus, and prefrontal cortex. Thus, we predicted dose-dependent decreases in activation of these areas during VO performance. Methods Forty healthy social drinkers were administered 3 different doses of alcohol, individually tailored to their gender and weight. Participants performed a VO task while operating a virtual reality driving simulator in a 3T fMRI scanner. Results Analysis showed a dose-dependent linear decrease in Blood Oxygen Level Dependent activation during task performance, primarily in hippocampus, anterior cingulate, and dorsolateral prefrontal areas, with the least activation occurring during the high dose. Behavioral analysis showed a dose-dependent linear increase in reaction time, with no effects associated with either correct hits or false alarms. In all dose conditions, driving speed decreased significantly after a VO stimulus. However, at the high dose this decrease was significantly less. Passenger-side line crossings significantly increased at the high dose. Conclusions These results suggest that driving impairment during secondary task performance may be associated with alcohol-related effects on the above brain regions, which are involved with attentional processing/decision-making. Drivers with high blood alcohol concentrations may be less able to orient or detect novel or sudden stimuli during driving. PMID:19183133

Power Supply Fault Tolerant Reliability Study

DTIC Science & Technology

1991-04-01

easier to design than for equivalent bipolar transistors. MCDONNELL DOUGLAS ELECTRONICS SYSTEMS COMPANY 9. Base circuitry should be designed to drive...SWITCHING REGULATORS (Ref. 28), SWITCHING AND LINEAR POWER SUPPLY DESIGN (Ref. 25) 6. Sequence the turn-off/turn-on logic in an orderly and controllable ...for equivalent bipolar transistors. MCDONNELL DOUGLAS ELECTRONICS SYSTEMS COMPANY 8. Base circuitry should be designed to drive the transistor into

A compact optical fiber positioner

NASA Astrophysics Data System (ADS)

Hu, Hongzhuan; Wang, Jianping; Liu, Zhigang; Zhou, Zengxiang; Zhai, Chao; Chu, Jiaru

2016-07-01

In this paper, a compact optical fiber positioner is proposed, which is especially suitable for small scale and high density optical fiber positioning. Based on the positioning principle of double rotation, positioner's center shaft depends on planetary gear drive principle, meshing with the fixed annular gear central motor gear driving device to rotate, and the eccentric shaft rotated driving by a coaxial eccentric motor, both center and the eccentric shaft are supported by a rolling bearings; center and eccentric shaft are both designed with electrical zero as a reference point, and both of them have position-limiting capability to ensure the safety of fiber positioning; both eccentric and center shaft are designed to eliminating clearance with spring structure, and can eliminate the influence of gear gap; both eccentric and center motor and their driving circuit can be installed in the positioner's body, and a favorable heat sink have designed, the heat bring by positioning operation can be effectively transmit to design a focal plane unit through the aluminum component, on sleeve cooling spiral airway have designed, when positioning, the cooling air flow is inlet into install hole on the focal plate, the cooling air flow can effectively take away the positioning's heat, to eliminate the impact of the focus seeing. By measuring position device's sample results show that: the unit accuracy reached 0.01mm, can meet the needs of fiber positioning.

Distracted Driving in Teens With and Without Attention-Deficit/Hyperactivity Disorder.

PubMed

Stavrinos, Despina; Garner, Annie A; Franklin, Crystal A; Johnson, Haley D; Welburn, Sharon C; Griffin, Russell; Underhill, Andrea T; Fine, Philip R

2015-01-01

This study is among the first to examine the effect of talking on a cell phone or text messaging while driving in teens with and without attention deficit/hyperactivity disorder (ADHD). Teens (average age 17years) with a diagnosis of ADHD (N=16) were matched with typically developing controls (N=18). All participants operated a driving simulator while (1) conversing on a cell phone, (2) text messaging, and (3) with no distraction during a baseline condition. Six indicators of driving performance were recorded: (a) time to complete the drive; (b) lane deviations; (c) variability in lane position (i.e., root mean square [RMS]); (d) reaction time; (e) motor vehicle collisions; and, (f) speed fluctuation. Significantly greater variation in lane position occurred in the texting task compared to no task and the cell phone task. While texting, in particular, teens with ADHD took significantly less time to complete the scenario. No significant main effects of group were found. Generally, those with ADHD did not differ in regard to driving performance, when compared to controls, with the exception of one outcome: time to complete scenario. These findings suggest that distracted driving impairs driving performance of teen drivers, regardless of ADHD status. Texting while driving had the greatest negative impact on driving performance, particularly with regard to variability in lane position (i.e., RMS). This study sheds light on key issues regarding injury prevention, with the intent of providing pediatric care providers with the knowledge to inform teen drivers of risks associated with distracted driving which will ultimately result in reduced rates of motor vehicle crashes and concomitant injuries. Published by Elsevier Inc.

Distracted Driving in Teens with and without Attention-Deficit/Hyperactivity Disorder

PubMed Central

Stavrinos, Despina; Garner, Annie A.; Franklin, Crystal A.; Johnson, Haley D.; Welburn, Sharon C.; Griffin, Russell; Underhill, Andrea T.; Fine, Philip R.

2015-01-01

Objective This study is among the first to examine the effect of talking on a cell phone or text messaging while driving in teens with and without Attention Deficit/Hyperactivity Disorder (ADHD). Method Teens (average age 17 years) with a diagnosis of ADHD (N=16) were matched with typically developing controls (N=18). All participants operated a driving simulator while (1) conversing on a cell phone, (2) text messaging, and (3) with no distraction during a baseline condition. Six indicators of driving performance were recorded: (a) time to complete the drive; (b) lane deviations; (c) variability in lane position (i.e., Root Mean Square [RMS]); (d) reaction time; (e) motor vehicle collisions; and, (f) speed fluctuation. Results Significantly greater variation in lane position occurred in the texting task compared to no task and the cell phone task. While texting, in particular, teens with ADHD took significantly less time to complete the scenario. No significant main effects of group were found. Conclusions Generally, those with ADHD did not differ in regard to driving performance, when compared to controls, with the exception of one outcome: time to complete scenario. These findings suggest that distracted driving impairs driving performance of teen drivers, regardless of ADHD status. Texting while driving had the greatest negative impact on driving performance, particularly with regard to variability in lane position (i.e., RMS). This study sheds light on key issues regarding injury prevention, with the intent of providing pediatric care providers with the knowledge to inform teen drivers of risks associated with distracted driving which will ultimately result in reduced rates of motor vehicle crashes and concomitant injuries. PMID:26049214

A linearly-polarized Nd:YVO4/KTP microchip green laser.

PubMed

Jung, C; Yu, B-A; Kim, I-S; Lee, Y L; Yu, N E; Ko, D-K

2009-10-26

We described the principle and the fabrication of a Nd:YVO(4)/KTP microchip for the linearly-polarized green laser and verified its availability by manufacturing and characterizing the green laser using the microchip. Under the driving condition having the modulation frequency of 60 Hz and the duty ratio of 25%, the laser showed the stable linear polarization, the maximum average power of 37 mW, yielding the high electrical-to-optical efficiency of 10.9%.

Time Delay Estimation

DTIC Science & Technology

1976-04-09

of the signal and noise remain HH ***^-^*--~ 53 h, to r(Mc) h2(r» r(we) Figure 3-2 Sy&toetric Impulse Response for Two FIR Linear Phase...Inputs x,y and Outputs x.j. , 15 2-2 Linear System with Impulse Response h("r) 23 2-3 Model of Error Resulting from Linearly Filtering x(t) to...Corrupted with Additive Noise 42 2-6 Model of Directional Signal Corrupted with Additive Noise and Processed .... 45 2-7 Source Driving Two

The Position Control of the Surface Motor with the Poles Distribution of Triangular Lattice

NASA Astrophysics Data System (ADS)

Watada, Masaya; Katsuyama, Norikazu; Ebihara, Daiki

Recently, as for the machine tools or industrial robots, high performance, accuracy, etc. are demanded. Generally, when drive of many degrees of freedom is required in the machine tools or industrial robots, it has realized by using two or more motors. For example, two-dimensional positioning stages such as the X-Y plotter or the X-Y stage are enabling the two-dimensional drive by using each one motor in the direction of x, y. In order to use plural motors, these, however, have problems that equipment becomes large and complicate control system. From such problems, the Surface Motor (SFM) that can drive two directions by only one motor is researched. Authors have proposed SFM that considered wide range movement and the application to a curved surface. In this paper, the characteristics of the micro step drive by the open loop control are showed. Introduction of closed loop control for highly accurate positioning, moreover, is examined. The drive characteristics by each control are compared.

Opportunity's Arm in 'Hover-Stow' Position

NASA Technical Reports Server (NTRS)

2006-01-01

In January 2006, NASA's Mars Exploration Rover team adopted a new strategy for carrying Opportunity's robotic arm (the instrument deployment device with its turret of four tools at the end) when the rover is driving.

On short drives over smooth terrain, Opportunity now holds the arm in a 'hover-stow' position as shown in this image taken by the navigation camera during the rover's 706th Martian day, or sol (Jan. 18, 2006), with elbow forward and the tool turret held above the rover deck. (In this image, the Moessbauer spectrometer is facing upwards, the alpha particle X-ray spectrometer faces to the right and the rock abrasion tool faces to the left). On longer or rougher drives, Opportunity still holds the arm in the original stow position used throughout the mission, tucked underneath the deck.

During Opportunity's 654th sol (Nov. 25, 2005), symptoms began appearing that have been diagnosed as a broken wire in the motor windings for the azimuth actuator at the shoulder joint, a motor that moves the arm from side to side. The motor still works when given extra current, but the change in strategy for stowing the arm results from concern that, if the motor were to completely fail with the arm in the original stow position, the arm could no longer be unstowed for use. If that motor were to fail while the arm is in the hover-stow position, the arm could still be manipulated for full use of the tools on the turret. However, the hover-stow position gives less protection to the arm during drives. Concern about protecting the arm during drives led to the compromise strategy of using hover-stow only during short, smooth drives.

Measuring the Attitudes of Novice Drivers with Autism Spectrum Disorder as an Indication of Apprehensive Driving: Going beyond Basic Abilities

ERIC Educational Resources Information Center

Ross, Veerle; Cox, Daniel J.; Reeve, Ron; Brown, Timothy; Moncrief, Matthew; Schmitt, Rose; Gaffney, Gary

2018-01-01

For some individuals with autism spectrum disorder, driving apprehension may interfere with the acquisition and application of driving privileges. The Driving Attitude Scale Parent-Report provides an indication of novice drivers' positive and negative attitudes toward driving. Responses were compared for parents of 66 autism spectrum disorder and…

Speed ratio but cabin temperature positively correlated with increased heart rates among professional drivers during car races.

PubMed

Yanagida, Ryo; Takahashi, Kiichi; Miura, Masaru; Nomura, Masahiro; Ogawa, Yojiro; Aoki, Ken; Iwasaki, Ken-Ichi

2016-11-01

The present study measures heart rate (HR) on a number of professional race-car drivers during actual car races through annual seasons to test hypotheses that faster relative speed and higher cabin temperature would induce higher HR. Heart rates in fifteen male drivers (31.2 ± 5.5 years old) were obtained by chest-strap sensors during official-professional 13 races. Average HR was calculated while the driver was racing from the start to the end of each race. The average HR during races was 164.5 ± 15.1 beats min -1 and the average amount of time each driver spent driving per race was 54.2 ± 13.7 min. Average HR significantly and positively correlated with mean speed ratio (P < 0.001), but not with the average cabin temperatures (P = 0.533, range 25.6-41.8 °C) by the multiple linear regression analysis. Both average HR and mean speed ratio were significantly lower under wet, than dry conditions (151.9 ± 16.5 vs. 168.3 ± 12.5 beats min -1 , 86.9 ± 4.4 vs. 93.4 ± 1.5 %). The cardiovascular system of drivers is considerably stressed at extremely high HR. This high average HR positively correlated with mean speed ratio, suggesting that faster driving speed would induce greater cardiovascular stress to professional drivers during actual races. However, contrary to our hypothesis, cabin temperature was not significantly correlated with average HR. It is speculated that direct body cooling systems used in this professional race category work well against increases in HR by thermal stress under the temperature range found herein.

Design of a radio telescope surface segment actuator based on a form-closed eccentric cam

NASA Astrophysics Data System (ADS)

Smith, David R.

2014-07-01

As radio telescopes have reached larger diameters and higher frequencies, it is typically not possible to meet their surface accuracy specifications using passive homology-based designs. The most common solution to this problem in the current generation of large, high-frequency radio telescopes is to employ a system of linear actuators to correct the surface shape of the primary reflector. The exact specifications of active surface actuators vary with the telescope. However, they have many common features, some of which drive their design. In general, these actuators must provide precise and repeatable positioning under significant loads during operation and they must withstand even higher loads for survival conditions. For general safety, they typically must hold position in the event of a power failure and must incorporate position limits, whether electrical, mechanical, or both. Because the number of actuators is generally high for large active surfaces (hundreds or even thousands of actuators), they must also be reliable and of reasonable individual cost. Finally, for maximum flexibility in their installation, they must be compact. This paper presents a concept for an active surface actuator based on a form-closed eccentric cam (kinematically, a Scotch Yoke mechanism). Such a design is limited in stroke, but offers potential advantages in terms of manufacture, compactness, measurement, and survival loading. The paper demonstrates that some of the expected advantages cannot be practically realized, due to dimensions that are driven by survival loading conditions. As a result, this concept is likely to offer an advantage over conventional screw-type actuators only for cases where actuator runaway and stall are the driving considerations.

Improvement of retinal blood vessel detection using morphological component analysis.

PubMed

Imani, Elaheh; Javidi, Malihe; Pourreza, Hamid-Reza

2015-03-01

Detection and quantitative measurement of variations in the retinal blood vessels can help diagnose several diseases including diabetic retinopathy. Intrinsic characteristics of abnormal retinal images make blood vessel detection difficult. The major problem with traditional vessel segmentation algorithms is producing false positive vessels in the presence of diabetic retinopathy lesions. To overcome this problem, a novel scheme for extracting retinal blood vessels based on morphological component analysis (MCA) algorithm is presented in this paper. MCA was developed based on sparse representation of signals. This algorithm assumes that each signal is a linear combination of several morphologically distinct components. In the proposed method, the MCA algorithm with appropriate transforms is adopted to separate vessels and lesions from each other. Afterwards, the Morlet Wavelet Transform is applied to enhance the retinal vessels. The final vessel map is obtained by adaptive thresholding. The performance of the proposed method is measured on the publicly available DRIVE and STARE datasets and compared with several state-of-the-art methods. An accuracy of 0.9523 and 0.9590 has been respectively achieved on the DRIVE and STARE datasets, which are not only greater than most methods, but are also superior to the second human observer's performance. The results show that the proposed method can achieve improved detection in abnormal retinal images and decrease false positive vessels in pathological regions compared to other methods. Also, the robustness of the method in the presence of noise is shown via experimental result. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Model-based sensorimotor integration for multi-joint control: development of a virtual arm model.

PubMed

Song, D; Lan, N; Loeb, G E; Gordon, J

2008-06-01

An integrated, sensorimotor virtual arm (VA) model has been developed and validated for simulation studies of control of human arm movements. Realistic anatomical features of shoulder, elbow and forearm joints were captured with a graphic modeling environment, SIMM. The model included 15 musculotendon elements acting at the shoulder, elbow and forearm. Muscle actions on joints were evaluated by SIMM generated moment arms that were matched to experimentally measured profiles. The Virtual Muscle (VM) model contained appropriate admixture of slow and fast twitch fibers with realistic physiological properties for force production. A realistic spindle model was embedded in each VM with inputs of fascicle length, gamma static (gamma(stat)) and dynamic (gamma(dyn)) controls and outputs of primary (I(a)) and secondary (II) afferents. A piecewise linear model of Golgi Tendon Organ (GTO) represented the ensemble sampling (I(b)) of the total muscle force at the tendon. All model components were integrated into a Simulink block using a special software tool. The complete VA model was validated with open-loop simulation at discrete hand positions within the full range of alpha and gamma drives to extrafusal and intrafusal muscle fibers. The model behaviors were consistent with a wide variety of physiological phenomena. Spindle afferents were effectively modulated by fusimotor drives and hand positions of the arm. These simulations validated the VA model as a computational tool for studying arm movement control. The VA model is available to researchers at website http://pt.usc.edu/cel .

Dense plasma formation on the surface of a ferroelectric induced by a driving pulse with a fast fall time

NASA Astrophysics Data System (ADS)

Chirko, K.; Krasik, Ya. E.; Sayapin, A.; Felsteiner, J.; Bernshtam, V.

2003-08-01

Experimental results are presented of dense plasma formation on the surface of a BaTi-based ferroelectric sample during the fall time of a driving pulse. A negative or positive driving pulse (⩽14 kV), with a slow rise time (˜450 ns) and a fast fall time (40-200 ns), was applied to the rear electrode of the ferroelectric. It was found by different electrical, optical, and spectroscopic diagnostics that this method allows one to form a plasma with a larger density (˜3×1013 cm-3) as compared with that formed by a driving pulse with a fast rise time (⩽4×1012 cm-3). It was shown that the shorter the fall time of the driving pulse the more intense plasma formation occurs. The most uniform and dense plasma formation occurs with a positive driving pulse. In addition, it was found that the shorter the fall time of the positive driving pulse the larger are the current amplitude, the energy, and the divergence of the emitted electrons. The obtained results are discussed in terms of the surface plasma formation and the compensation process of the polarization surface charge of the ferroelectric sample.

Effects of central nervous system drugs on driving: speed variability versus standard deviation of lateral position as outcome measure of the on-the-road driving test.

PubMed

Verster, Joris C; Roth, Thomas

2014-01-01

The on-the-road driving test in normal traffic is used to examine the impact of drugs on driving performance. This paper compares the sensitivity of standard deviation of lateral position (SDLP) and SD speed in detecting driving impairment. A literature search was conducted to identify studies applying the on-the-road driving test, examining the effects of anxiolytics, antidepressants, antihistamines, and hypnotics. The proportion of comparisons (treatment versus placebo) where a significant impairment was detected with SDLP and SD speed was compared. About 40% of 53 relevant papers did not report data on SD speed and/or SDLP. After placebo administration, the correlation between SDLP and SD speed was significant but did not explain much variance (r = 0.253, p = 0.0001). A significant correlation was found between ΔSDLP and ΔSD speed (treatment-placebo), explaining 48% of variance. When using SDLP as outcome measure, 67 significant treatment-placebo comparisons were found. Only 17 (25.4%) were significant when SD speed was used as outcome measure. Alternatively, for five treatment-placebo comparisons, a significant difference was found for SD speed but not for SDLP. Standard deviation of lateral position is a more sensitive outcome measure to detect driving impairment than speed variability.

Nonlinear verification of a linear critical gradient model for energetic particle transport by Alfven eigenmodes

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

Bass, Eric M.; Waltz, R. E.

Here, a “stiff transport” critical gradient model of energetic particle (EP) transport by EPdriven Alfven eigenmodes (AEs) is verified against local nonlinear gyrokinetic simulations of a well-studied beam-heated DIII-D discharge 146102. A greatly simplifying linear “recipe” for the limiting EP-density gradient (critical gradient) is considered here. In this recipe, the critical gradient occurs when the AE linear growth rate, driven mainly by the EP gradient, exceeds the ion temperature gradient (ITG) or trapped electron mode (TEM) growth rate, driven by the thermal plasma gradient, at the same toroidal mode number (n) as the AE peak growth, well below the ITG/TEMmore » peak n. This linear recipe for the critical gradient is validated against the critical gradient determined from far more expensive local nonlinear simulations in the gyrokinetic code GYRO, as identified by the point of transport runaway when all driving gradients are held fixed. The reduced linear model is extended to include the stabilization from equilibrium E×B velocity shear. The nonlinear verification unambiguously endorses one of two alternative recipes proposed in Ref. 1: the EP-driven AE growth rate should be determined with rather than without added thermal plasma drive.« less

Nonlinear verification of a linear critical gradient model for energetic particle transport by Alfven eigenmodes

DOE PAGES

Bass, Eric M.; Waltz, R. E.

2017-12-08

Here, a “stiff transport” critical gradient model of energetic particle (EP) transport by EPdriven Alfven eigenmodes (AEs) is verified against local nonlinear gyrokinetic simulations of a well-studied beam-heated DIII-D discharge 146102. A greatly simplifying linear “recipe” for the limiting EP-density gradient (critical gradient) is considered here. In this recipe, the critical gradient occurs when the AE linear growth rate, driven mainly by the EP gradient, exceeds the ion temperature gradient (ITG) or trapped electron mode (TEM) growth rate, driven by the thermal plasma gradient, at the same toroidal mode number (n) as the AE peak growth, well below the ITG/TEMmore » peak n. This linear recipe for the critical gradient is validated against the critical gradient determined from far more expensive local nonlinear simulations in the gyrokinetic code GYRO, as identified by the point of transport runaway when all driving gradients are held fixed. The reduced linear model is extended to include the stabilization from equilibrium E×B velocity shear. The nonlinear verification unambiguously endorses one of two alternative recipes proposed in Ref. 1: the EP-driven AE growth rate should be determined with rather than without added thermal plasma drive.« less

Solar shutter arrangement

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

Fulkerson, P.L.

1988-02-02

In a structure having a roof with a skylight including a glass panel which transmits solar energy, a shutter arrangement supported on the roof is described comprising an insulative flat one-piece solid shutter in the form of a panel selectively and linearly slidable on tracks which conceal the side edges thereof from a position blocking transmittal of solar energy through the glass panel of the skylight into an area within the structure to a position permitting transmittal of solar energy through the glass panel of the skylight into the area within the structure. The skylight presents a space between themore » glass panel and the selectively and linearly slidable insulative flat one-piece solid shutter, where the latter serves as the selective inner wall of the space contiguous with the area within the structure and the glass panel serves as the fixed outer wall of the space, where temperature responsive means is disposed within the space and in direct engagement with the inner surface of the glass panel, where the temperature responsive means is a black thermocouple operating a motor in a driving relationship with the insulative flat one-piece solid shutter. The insulative flat one-piece solid shutter is supported by a cable secured to a rotatable shaft controlled by the motor, where bi-directional movement of the rotatable shaft achieves raising and lowering of the insulative flat one-piece solid shutter to each of the solar energy blocking and transmittal positions, and where the insulative flat one-piece solid shutter includes a reflective surface facing the skylight and a decorative surface facing the area within the structure.« less

Electrodynamic pressure modulation of protein stability in cosolvents.

PubMed

Damodaran, Srinivasan

2013-11-19

Cosolvents affect structural stability of proteins in aqueous solutions. A clear understanding of the mechanism by which cosolvents impact protein stability is critical to understanding protein folding in a biological milieu. In this study, we investigated the Lifshitz-van der Waals dispersion interaction of seven different solutes with nine globular proteins and report that in an aqueous medium the structure-stabilizing solutes exert a positive electrodynamic pressure, whereas the structure-destabilizing solutes exert a negative electrodynamic pressure on the proteins. The net increase in the thermal denaturation temperature (ΔTd) of a protein in 1 M solution of various solutes was linearly related to the electrodynamic pressure (PvdW) between the solutes and the protein. The slope of the PvdW versus ΔTd plots was protein-dependent. However, we find a positive linear relationship (r(2) = 0.79) between the slope (i.e., d(ΔTd)/dPvdW) and the adiabatic compressibility (βs) of the proteins. Together, these results clearly indicate that the Lifshitz's dispersion forces are inextricably involved in solute-induced stabilization/destabilization of globular proteins. The positive and/or negative electrodynamic pressure generated by the solute-protein interaction across the water medium seems to be the fundamental mechanism by which solutes affect protein stability. This is at variance with the existing preferential hydration concept. The implication of these results is significant in the sense that, in addition to the hydrophobic effect that drives protein folding, the electrodynamic forces between the proteins and solutes in the biological milieu also might play a role in the folding process as well as in the stability of the folded state.

Design and construction of a novel rotary magnetostrictive motor

NASA Astrophysics Data System (ADS)

Zhou, Nanjia; Blatchley, Charles C.; Ibeh, Christopher C.

2009-04-01

Magnetostriction can be used to induce linear incremental motion, which is effective in giant magnetostrictive inchworm motors. Such motors possess the advantage of combining small step incremental motion with large force. However, continuous rotation may be preferred in practical applications. This paper describes a novel magnetostrictive rotary motor using terfenol-D (Tb0.3Dy0.7Fe1.9) material as the driving element. The motor is constructed of two giant magnetostrictive actuators with shell structured flexure-hinge and leaf springs. These two actuators are placed in a perpendicular position to minimize the coupling displacement of the two actuators. The principal design parameters of the actuators and strain amplifiers are optimally determined, and its static analysis is undertaken through finite element analysis software. The small movements of the magnetostrictive actuators are magnified by about three times using oval shell structured amplifiers. When two sinusoidal wave currents with 90° phase shift are applied to the magnetostrictive actuators, purely rotational movement can be produced as in the orbit of a Lissajous diagram in an oscillograph, and this movement is used to drive the rotor of the motor. A prototype has been constructed and tested.

Performance Estimation for Two-Dimensional Brownian Rotary Ratchet Systems

NASA Astrophysics Data System (ADS)

Tutu, Hiroki; Horita, Takehiko; Ouchi, Katsuya

2015-04-01

Within the context of the Brownian ratchet model, a molecular rotary system that can perform unidirectional rotations induced by linearly polarized ac fields and produce positive work under loads was studied. The model is based on the Langevin equation for a particle in a two-dimensional (2D) three-tooth ratchet potential of threefold symmetry. The performance of the system is characterized by the coercive torque, i.e., the strength of the load competing with the torque induced by the ac driving field, and the energy efficiency in force conversion from the driving field to the torque. We propose a master equation for coarse-grained states, which takes into account the boundary motion between states, and develop a kinetic description to estimate the mean angular momentum (MAM) and powers relevant to the energy balance equation. The framework of analysis incorporates several 2D characteristics and is applicable to a wide class of models of smooth 2D ratchet potential. We confirm that the obtained expressions for MAM, power, and efficiency of the model can enable us to predict qualitative behaviors. We also discuss the usefulness of the torque/power relationship for experimental analyses, and propose a characteristic for 2D ratchet systems.

Injection locking of a two-mode electron oscillator with close frequencies

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

Starodubova, E. N.; Usacheva, S. A.; Ryskin, N. M.

2015-03-15

Theory of injection locking is developed for a two-mode electron maser with close frequencies, when the driving signal affects both modes. There exist two regimes of phase locking in which either first or second mode dominates. Hard transitions between the two regimes are observed with variation of the driving frequency. The results of numerical simulations are presented for the case of driving by a signal with linear frequency chirp, as well as by a signal with sinusoidal frequency modulation. The effect of bifurcation delay is observed with the increase of chirp rate.

A 15 MHz bandwidth, 60 V{sub pp}, low distortion power amplifier for driving high power piezoelectric transducers

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

Capineri, Lorenzo, E-mail: lorenzo.capineri@unifi.it

2014-10-01

This paper presents the design and the realization of a linear power amplifier with large bandwidth (15 MHz) capable of driving low impedance ultrasonic transducers. The output current driving capability (up to 5 A) and low distortion makes it suitable for new research applications using high power ultrasound in the medical and industrial fields. The electronic design approach is modular so that the characteristics can be scaled according to specific applications and implementation details for the circuit layout are reported. Finally the characterization of the power amplifier module is presented.

Design Study for an Actively Terrain-Adaptive Off-Road Vehicle.

DTIC Science & Technology

1982-06-03

at right. I-u M K_ £.IKAI 3-CPTF. 4.1.1K L019SN $-DATA I-INPiUg 7.W.’GCS. LOT I.IIIT 1191?M’ I.1Ki ANIMATION a.RtMDI- heMI .tfANIMTION T%*9I .IPU DRIVE ...relationship between drive actuator displacement and foot displacement achievable with this geometry is attractive from the point of view of the control...with progress in optimizing the drive actuator mounting to minimize non-linearity have led to retention of the four-bar leg as the operative design. The

Scissor thrust valve actuator

DOEpatents

DeWall, Kevin G.; Watkins, John C; Nitzel, Michael E.

2006-08-29

Apparatus for actuating a valve includes a support frame and at least one valve driving linkage arm, one end of which is rotatably connected to a valve stem of the valve and the other end of which is rotatably connected to a screw block. A motor connected to the frame is operatively connected to a motor driven shaft which is in threaded screw driving relationship with the screw block. The motor rotates the motor driven shaft which drives translational movement of the screw block which drives rotatable movement of the valve driving linkage arm which drives translational movement of the valve stem. The valve actuator may further include a sensory control element disposed in operative relationship with the valve stem, the sensory control element being adapted to provide control over the position of the valve stem by at least sensing the travel and/or position of the valve stem.

FAN HOUSE INTERIOR. THREE MOTOR DRIVES FOR POSITIVE DISPLACEMENT BLOWERS ...

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

FAN HOUSE INTERIOR. THREE MOTOR DRIVES FOR POSITIVE DISPLACEMENT BLOWERS LINE UP ON NORTH WALL. CONCRETE PEDESTALS. CAMERA FACES NORTHEAST. INL NEGATIVE NO. 4291. Unknown Photographer, 2/26/1952 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

The design of a small linear-resonant, split Stirling cryogenic refrigerator compressor

NASA Technical Reports Server (NTRS)

Ackermann, R. A.

1985-01-01

The development of a small linear-resonant compressor for use in a 1/4-watt, 78K, split Stirling cryogenic refrigerator is discussed. The compressor contains the following special features: (1) a permanent-magnet linear motor; (2) resonant dynamics; (3) dynamic balancing; and (4) a close-clearance seal between the compressor piston and cylinder. This paper describes the design of the compressor, and presents component test data and system test data for the compressor driving a 1/4-watt expander.

A preliminary investigation of the relationships between historical crash and naturalistic driving.

PubMed

Pande, Anurag; Chand, Sai; Saxena, Neeraj; Dixit, Vinayak; Loy, James; Wolshon, Brian; Kent, Joshua D

2017-04-01

This paper describes a project that was undertaken using naturalistic driving data collected via Global Positioning System (GPS) devices to demonstrate a proof-of-concept for proactive safety assessments of crash-prone locations. The main hypothesis for the study is that the segments where drivers have to apply hard braking (higher jerks) more frequently might be the "unsafe" segments with more crashes over a long-term. The linear referencing methodology in ArcMap was used to link the GPS data with roadway characteristic data of US Highway 101 northbound (NB) and southbound (SB) in San Luis Obispo, California. The process used to merge GPS data with quarter-mile freeway segments for traditional crash frequency analysis is also discussed in the paper. A negative binomial regression analyses showed that proportion of high magnitude jerks while decelerating on freeway segments (from the driving data) was significantly related with the long-term crash frequency of those segments. A random parameter negative binomial model with uniformly distributed parameter for ADT and a fixed parameter for jerk provided a statistically significant estimate for quarter-mile segments. The results also indicated that roadway curvature and the presence of auxiliary lane are not significantly related with crash frequency for the highway segments under consideration. The results from this exploration are promising since the data used to derive the explanatory variable(s) can be collected using most off-the-shelf GPS devices, including many smartphones. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evaluating and Enhancing Driving Ability among Teens with Autism Spectrum Disorder

DTIC Science & Technology

2015-06-01

see Appendix 1). It assesses both positive and negative cognitions, physical arousal, and behaviors that relate to contemplating driving, preparing to...driving. Their eagerness or discomfort may be expressed through their thoughts, actions, or physical responses. To what extent does your teen do the...drive? 0 1 2 3 Avoids talking about driving? 0 1 2 3 Smiles and is physically excited about possibly driving? 0 1 2 3 Becomes agitated or tense when

Photoelectric angle converter

NASA Astrophysics Data System (ADS)

Podzharenko, Volodymyr A.; Kulakov, Pavlo I.

2001-06-01

The photo-electric angle transmitter of rotation is offered, at which the output voltage is linear function of entering magnitude. In a transmitter the linear phototransducer is used on the basis of pair photo diode -- operating amplifier, which output voltage is linear function of the area of an illuminated photosensitive stratum, and modulator of a light stream of the special shape, which ensures a linear dependence of this area from an angle of rotation. The transmitter has good frequent properties and can be used for dynamic measurements of an angular velocity and angle of rotation, in systems of exact drives and systems of autocontrol.

E × B flow shear drive of the linear low- n modes of EHO in the QH-mode regime [ E × B flow shear drive of EHO in the QH-mode regime

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

Xu, G. S.; Wan, B. N.; Wang, Y. F.

A new mechanism is identified for driving the edge harmonic oscillations (EHOs) in the quiescent H-mode (QH-mode) regime, where a strong E × B flow shear destabilizes low-n kink/peeling modes, separately from the previously found Kelvin-Helmholtz drive. We find that the differential advection of mode vorticity by sheared E × B flows modifies the two-dimensional pattern of mode electrostatic potential perpendicular to the magnetic field lines, which in turn causes a radial expansion of the mode structure, an increase of field line bending away from the mode rational surface, and a reduction of inertial stabilization. This enhances the kink drivemore » as the parallel wavenumber increases significantly away from the rational surface where the magnetic shear is also strong. A newly developed model reproduces the observations that at high E × B flow shear only a few low-n modes remain unstable, consistent with the EHO behavior, while at low E × B flow shear the unstable mode spectrum is significantly broadened, consistent with the low-n broadband electromagnetic turbulence behavior observed recently in the DIII-D tokamak. This destabilization is also shown to be independent of the sign of the flow shear, as observed experimentally, and has not been taken into 2 / 46 account in previous pedestal linear stability analyses. Verification of the veracity of this EHO mechanism will require analysis of the nonlinear evolution of low-n kink/peeling modes so destabilized in the linear regime.« less

E × B flow shear drive of the linear low- n modes of EHO in the QH-mode regime [ E × B flow shear drive of EHO in the QH-mode regime

DOE PAGES

Xu, G. S.; Wan, B. N.; Wang, Y. F.; ...

2017-07-18

A new mechanism is identified for driving the edge harmonic oscillations (EHOs) in the quiescent H-mode (QH-mode) regime, where a strong E × B flow shear destabilizes low-n kink/peeling modes, separately from the previously found Kelvin-Helmholtz drive. We find that the differential advection of mode vorticity by sheared E × B flows modifies the two-dimensional pattern of mode electrostatic potential perpendicular to the magnetic field lines, which in turn causes a radial expansion of the mode structure, an increase of field line bending away from the mode rational surface, and a reduction of inertial stabilization. This enhances the kink drivemore » as the parallel wavenumber increases significantly away from the rational surface where the magnetic shear is also strong. A newly developed model reproduces the observations that at high E × B flow shear only a few low-n modes remain unstable, consistent with the EHO behavior, while at low E × B flow shear the unstable mode spectrum is significantly broadened, consistent with the low-n broadband electromagnetic turbulence behavior observed recently in the DIII-D tokamak. This destabilization is also shown to be independent of the sign of the flow shear, as observed experimentally, and has not been taken into 2 / 46 account in previous pedestal linear stability analyses. Verification of the veracity of this EHO mechanism will require analysis of the nonlinear evolution of low-n kink/peeling modes so destabilized in the linear regime.« less

Positive effects of Red Bull® Energy Drink on driving performance during prolonged driving.

PubMed

Mets, Monique A J; Ketzer, Sander; Blom, Camilla; van Gerven, Maartje H; van Willigenburg, Gitta M; Olivier, Berend; Verster, Joris C

2011-04-01

The purpose of this study was to examine if Red Bull® Energy Drink can counteract sleepiness and driving impairment during prolonged driving. Twenty-four healthy volunteers participated in this double-blind placebo-controlled crossover study. After 2 h of highway driving in the STISIM driving simulator, subjects had a 15-min break and consumed Red Bull® Energy Drink (250 ml) or placebo (Red Bull® Energy Drink without the functional ingredients: caffeine, taurine, glucuronolactone, B vitamins (niacin, pantothenic acid, B6, B12), and inositol) before driving for two additional hours. A third condition comprised 4 h of uninterrupted driving. Primary parameter was the standard deviation of lateral position (SDLP), i.e., the weaving of the car. Secondary parameters included SD speed, subjective driving quality, sleepiness, and mental effort to perform the test. No significant differences were observed during the first 2 h of driving. Red Bull® Energy Drink significantly improved driving relative to placebo: SDLP was significantly reduced during the 3rd (p < 0.046) and 4th hour of driving (p < 0.011). Red Bull® Energy Drink significantly reduced the standard deviation of speed (p < 0.004), improved subjective driving quality (p < 0.0001), and reduced mental effort to perform the test (p < 0.024) during the 3rd hour of driving. Subjective sleepiness was significantly decreased during both the 3rd and 4th hour of driving after Red Bull® Energy Drink (p < 0.001 and p < 0.009, respectively). Relative to uninterrupted driving, Red Bull® Energy Drink significantly improved each parameter. Red Bull® Energy Drink significantly improves driving performance and reduces driver sleepiness during prolonged highway driving.

Apparatus and method for reducing inductive coupling between levitation and drive coils within a magnetic propulsion system

DOEpatents

Post, Richard F.

2001-01-01

An apparatus and method is disclosed for reducing inductive coupling between levitation and drive coils within a magnetic levitation system. A pole array has a magnetic field. A levitation coil is positioned so that in response to motion of the magnetic field of the pole array a current is induced in the levitation coil. A first drive coil having a magnetic field coupled to drive the pole array also has a magnetic flux which induces a parasitic current in the levitation coil. A second drive coil having a magnetic field is positioned to attenuate the parasitic current in the levitation coil by canceling the magnetic flux of the first drive coil which induces the parasitic current. Steps in the method include generating a magnetic field with a pole array for levitating an object; inducing current in a levitation coil in response to motion of the magnetic field of the pole array; generating a magnetic field with a first drive coil for propelling the object; and generating a magnetic field with a second drive coil for attenuating effects of the magnetic field of the first drive coil on the current in the levitation coil.

Threshold Fatigue Crack Growth in Ti-6Al-2Sn-4Zr-6Mo.

DTIC Science & Technology

1987-12-01

vii I. Introduction ................... ........ ........... 1 Overviev .................................... 1 Background...threshold region. 7. All experiments were conducted under fully automated I’ computer control using a laser interferometric displacement gage (IDG) to...reduction in the local driving force. This non-linear crack 0 appears to grow slower than a linear crack and therefore results in lover than actual computed

VIEW OF LIVING ROOM DOORS SHOWN IN CLOSED POSITION. VIEW ...

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

VIEW OF LIVING ROOM DOORS SHOWN IN CLOSED POSITION. VIEW FACING WEST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Three-Bedroom Single-Family Type 9, Birch Circle, Elm Drive, Elm Circle, and Date Drive, Pearl City, Honolulu County, HI

Oscillating-Linear-Drive Vacuum Compressor for CO2

NASA Technical Reports Server (NTRS)

Izenson, Michael G.; Shimko, Martin

2005-01-01

A vacuum compressor has been designed to compress CO2 from approximately equal to 1 psia (approximately equal to 6.9 kPa absolute pressure) to approximately equal to 75 psia (approximately equal to 0.52 MPa), to be insensitive to moisture, to have a long operational life, and to be lightweight, compact, and efficient. The compressor consists mainly of (1) a compression head that includes hydraulic diaphragms, a gas-compression diaphragm, and check valves; and (2) oscillating linear drive that includes a linear motor and a drive spring, through which compression force is applied to the hydraulic diaphragms. The motor is driven at the resonance vibrational frequency of the motor/spring/compression-head system, the compression head acting as a damper that takes energy out of the oscillation. The net effect of the oscillation is to cause cyclic expansion and contraction of the gas-compression diaphragm, and, hence, of the volume bounded by this diaphragm. One-way check valves admit gas into this volume from the low-pressure side during expansion and allow the gas to flow out to the high-pressure side during contraction. Fatigue data and the results of diaphragm stress calculations have been interpreted as signifying that the compressor can be expected to have an operational life of greater than 30 years with a confidence level of 99.9 percent.

Driving ability in sleep apnoea patients before and after CPAP treatment: evaluation on a road safety platform.

PubMed

Mazza, S; Pépin, J-L; Naëgelé, B; Rauch, E; Deschaux, C; Ficheux, P; Lévy, P

2006-11-01

Sleepiness is considered to be the major cause of increased traffic accidents in patients with obstructive sleep apnoea syndrome (OSAS). Until now, OSAS patients' driving ability has been assessed using driving simulators, but no assessment in a more natural driving environment has been carried out to date. The aim of the present study was to evaluate driving parameters in OSAS and in controls on a road safety platform, and to compare them with attentional in-laboratory measures before and after continuous positive airway pressure treatment. The parameters measured were: reaction time; distance to stop and number of collisions on the platform; maintenance of wakefulness; and sustained, selective and divided attention in laboratory. Patients exhibited much longer reaction times than controls, leading to a lengthening of the vehicle's stopping distance of 8.8 m at 40 km.h(-1) and to twice the number of collisions. Patients did not demonstrate objective sleepiness or selective and sustained attention deficits. Divided attention deficits were found. However, they did not allow the prediction of real driving impairment. After CPAP treatment, there was no longer any difference between patients and controls regarding driving and attention performances. Driving abilities are significantly impaired in obstructive sleep apnoea syndrome. After continuous positive airway pressure treatment, deficits were normalised. This stresses the importance of evaluating attentional parameters in apnoeic patients and of offering continuous positive airway pressure treatment even to non-sleepy subjects.

Cognitive problems, self-rated changes in driving skills, driving-related discomfort and self-regulation of driving in old drivers.

PubMed

Meng, Annette; Siren, Anu

2012-11-01

Ageing in general is associated with functional decline that may have an adverse effect on driving. Nevertheless, older drivers have been found to show good judgement and to self-regulate their driving, which may enable them to continue driving safely despite functional decline. The process of the self-monitoring of driving ability and the awareness of functional decline, and its association with the self-regulation of driving is, however, not fully understood. The aim of the present study was to examine the perceived changes in driving skills, the discomfort experienced in driving, and the self-regulation of driving as measured by the avoidance of certain driving situations by older drivers with different levels of self-rated cognitive problems. Eight hundred and forty Danish drivers aged 75-95 completed a structured telephone interview. The results showed that the recognition of cognitive problems was associated with an experience of improvement in higher level driving skills but also of a decline in lower level driving skills. Moreover, cognitive problems recognised by drivers were associated with discomfort in, and avoidance of, driving situations. Finally, a linear relationship between discomfort in driving and avoidance was found and this tended to be stronger for drivers recognising cognitive problems. The results indicate that older drivers who recognise problems with cognitive functions display good self-assessment of changes in their driving skills. In addition, the results suggest that driving-related discomfort is an important factor affecting the self-regulation of driving. Finally, the findings indicate that driving-related discomfort functions as an indirect self-monitoring of driving ability and may contribute to the safe driving performance of Danish older drivers. Copyright © 2012 Elsevier Ltd. All rights reserved.

Method of Controlling Steering of a Ground Vehicle

NASA Technical Reports Server (NTRS)

Guo, Raymond (Inventor); Atluri, Venkata Prasad (Inventor); Bluethmann, William J. (Inventor); Lee, Chunhao J. (Inventor); Vitale, Robert L. (Inventor); Dawson, Andrew D. (Inventor)

2016-01-01

A method of controlling steering of a vehicle through setting wheel angles of a plurality of modular electronic corner assemblies (eModules) is provided. The method includes receiving a driving mode selected from a mode selection menu. A position of a steering input device is determined in a master controller. A velocity of the vehicle is determined, in the master controller, when the determined position of the steering input device is near center. A drive mode request corresponding to the selected driving mode to the plurality of steering controllers is transmitted to the master controller. A required steering angle of each of the plurality of eModules is determined, in the master controller, as a function of the determined position of the steering input device, the determined velocity of the vehicle, and the selected first driving mode. The eModules are set to the respective determined steering angles.

A positive view on road safety: Can 'car karma' contribute to safe driving styles?

PubMed

Kleisen, Lucienne M B

2013-01-01

Many studies in the field of road safety are occupied with studying road unsafety since it generally concentrates on traffic crashes, crash, risk, and aberrant driving behaviour, especially in relation to young drivers. However, this study shows there is scope for thinking about driving and driver training from a different vantage point, that is in terms of safe or normal driving. The findings are reported from four group interviews with young drivers (18-25 years of age); the young drivers discussed their ideas of safe driving and their reasons for using (or not using) safe driving styles. The data show a type of optimistic thinking among young drivers which they call 'car karma'. This finding offers an opportunity to reconceptualise driving in a way that is focused on normal, safe driving styles, a topic that has received less attention in the past. The paper argues that greater focus on safe driving styles could be more conducive to young drivers actually driving safely than focusing on, for instance, crashes, which on an individual level are relatively rare (Elander et al., 1993, p. 277). Based on empirical research, the first positively stated definition of road safety is proposed based on the notion of 'car karma'. Copyright © 2012 Elsevier Ltd. All rights reserved.

Adolescents, peers, and motor vehicles: the perfect storm?

PubMed

Allen, Joseph P; Brown, B Bradford

2008-09-01

Motor-vehicle crashes are a leading cause of death among teenagers and in many instances appear linked to negative peer influences on adolescent driving behavior. This article examines a range of developmental and structural factors that potentially increase the risks associated with adolescent driving. Developmental risk factors for adolescents include a propensity toward engaging in deviant and risky behavior, a desire to please peers, and the potential cost to an adolescent of alienating peers with his or her behavior while driving. Structural features of the driving situation that create risks for negative peer influences on driving behavior include the inability of adolescents to look at peers who may be pressuring them, divided attention, the need to behave in a conventional manner among peers who may not value conventional behavior, and the lack of accountability by peers for the effects of any risky driving they promote. A range of potential peer influences are considered, including passive and active distraction and direct disruption of driving, as well as more positive influences, such as peer modeling of good driving behavior and positive reinforcement of good driving. Although the range of risk factors created by peers is large, this range presents a number of promising targets for intervention to improve teen driving safety.

Glaucoma and Driving: On-Road Driving Characteristics

PubMed Central

Wood, Joanne M.; Black, Alex A.; Mallon, Kerry; Thomas, Ravi; Owsley, Cynthia

2016-01-01

Purpose To comprehensively investigate the types of driving errors and locations that are most problematic for older drivers with glaucoma compared to those without glaucoma using a standardized on-road assessment. Methods Participants included 75 drivers with glaucoma (mean = 73.2±6.0 years) with mild to moderate field loss (better-eye MD = -1.21 dB; worse-eye MD = -7.75 dB) and 70 age-matched controls without glaucoma (mean = 72.6 ± 5.0 years). On-road driving performance was assessed in a dual-brake vehicle by an occupational therapist using a standardized scoring system which assessed the types of driving errors and the locations where they were made and the number of critical errors that required an instructor intervention. Driving safety was rated on a 10-point scale. Self-reported driving ability and difficulties were recorded using the Driving Habits Questionnaire. Results Drivers with glaucoma were rated as significantly less safe, made more driving errors, and had almost double the rate of critical errors than those without glaucoma. Driving errors involved lane positioning and planning/approach, and were significantly more likely to occur at traffic lights and yield/give-way intersections. There were few between group differences in self-reported driving ability. Conclusions Older drivers with glaucoma with even mild to moderate field loss exhibit impairments in driving ability, particularly during complex driving situations that involve tactical problems with lane-position, planning ahead and observation. These results, together with the fact that these drivers self-report their driving to be relatively good, reinforce the need for evidence-based on-road assessments for evaluating driving fitness. PMID:27472221

Glaucoma and Driving: On-Road Driving Characteristics.

PubMed

Wood, Joanne M; Black, Alex A; Mallon, Kerry; Thomas, Ravi; Owsley, Cynthia

2016-01-01

To comprehensively investigate the types of driving errors and locations that are most problematic for older drivers with glaucoma compared to those without glaucoma using a standardized on-road assessment. Participants included 75 drivers with glaucoma (mean = 73.2±6.0 years) with mild to moderate field loss (better-eye MD = -1.21 dB; worse-eye MD = -7.75 dB) and 70 age-matched controls without glaucoma (mean = 72.6 ± 5.0 years). On-road driving performance was assessed in a dual-brake vehicle by an occupational therapist using a standardized scoring system which assessed the types of driving errors and the locations where they were made and the number of critical errors that required an instructor intervention. Driving safety was rated on a 10-point scale. Self-reported driving ability and difficulties were recorded using the Driving Habits Questionnaire. Drivers with glaucoma were rated as significantly less safe, made more driving errors, and had almost double the rate of critical errors than those without glaucoma. Driving errors involved lane positioning and planning/approach, and were significantly more likely to occur at traffic lights and yield/give-way intersections. There were few between group differences in self-reported driving ability. Older drivers with glaucoma with even mild to moderate field loss exhibit impairments in driving ability, particularly during complex driving situations that involve tactical problems with lane-position, planning ahead and observation. These results, together with the fact that these drivers self-report their driving to be relatively good, reinforce the need for evidence-based on-road assessments for evaluating driving fitness.

Advanced simulation model for IPM motor drive with considering phase voltage and stator inductance

NASA Astrophysics Data System (ADS)

Lee, Dong-Myung; Park, Hyun-Jong; Lee, Ju

2016-10-01

This paper proposes an advanced simulation model of driving system for Interior Permanent Magnet (IPM) BrushLess Direct Current (BLDC) motors driven by 120-degree conduction method (two-phase conduction method, TPCM) that is widely used for sensorless control of BLDC motors. BLDC motors can be classified as SPM (Surface mounted Permanent Magnet) and IPM motors. Simulation model of driving system with SPM motors is simple due to the constant stator inductance regardless of the rotor position. Simulation models of SPM motor driving system have been proposed in many researches. On the other hand, simulation models for IPM driving system by graphic-based simulation tool such as Matlab/Simulink have not been proposed. Simulation study about driving system of IPMs with TPCM is complex because stator inductances of IPM vary with the rotor position, as permanent magnets are embedded in the rotor. To develop sensorless scheme or improve control performance, development of control algorithm through simulation study is essential, and the simulation model that accurately reflects the characteristic of IPM is required. Therefore, this paper presents the advanced simulation model of IPM driving system, which takes into account the unique characteristic of IPM due to the position-dependent inductances. The validity of the proposed simulation model is validated by comparison to experimental and simulation results using IPM with TPCM control scheme.

Strategic advertising plans to deter drunk driving

DOT National Transportation Integrated Search

1996-12-01

Primary objective for this study was to identify and profile subpopulations at highest risk for drinking and driving, and persons who may be in a position to intervene in their drinking and driving behavior. A related objective was to explore media m...

RF pulse shape control in the compact linear collider test facility

NASA Astrophysics Data System (ADS)

Kononenko, Oleksiy; Corsini, Roberto

2018-07-01

The Compact Linear Collider (CLIC) is a study for an electron-positron machine aiming at accelerating and colliding particles at the next energy frontier. The CLIC concept is based on the novel two-beam acceleration scheme, where a high-current low-energy drive beam generates RF in series of power extraction and transfer structures accelerating the low-current main beam. To compensate for the transient beam-loading and meet the energy spread specification requirements for the main linac, the RF pulse shape must be carefully optimized. This was recently modelled by varying the drive beam phase switch times in the sub-harmonic buncher so that, when combined, the drive beam modulation translates into the required voltage modulation of the accelerating pulse. In this paper, the control over the RF pulse shape with the phase switches, that is crucial for the success of the developed compensation model, is studied. The results on the experimental verification of this control method are presented and a good agreement with the numerical predictions is demonstrated. Implications for the CLIC beam-loading compensation model are also discussed.

Fuzzy Logic Controlled Solar Module for Driving Three- Phase Induction Motor

NASA Astrophysics Data System (ADS)

Afiqah Zainal, Nurul; Sooi Tat, Chan; Ajisman

2016-02-01

Renewable energy produced by solar module gives advantages for generated three- phase induction motor in remote area. But, solar module's ou tput is uncertain and complex. Fuzzy logic controller is one of controllers that can handle non-linear system and maximum power of solar module. Fuzzy logic controller used for Maximum Power Point Tracking (MPPT) technique to control Pulse-Width Modulation (PWM) for switching power electronics circuit. DC-DC boost converter used to boost up photovoltaic voltage to desired output and supply voltage source inverter which controlled by three-phase PWM generated by microcontroller. IGBT switched Voltage source inverter (VSI) produced alternating current (AC) voltage from direct current (DC) source to control speed of three-phase induction motor from boost converter output. Results showed that, the output power of solar module is optimized and controlled by using fuzzy logic controller. Besides that, the three-phase induction motor can be drive and control using VSI switching by the PWM signal generated by the fuzzy logic controller. This concluded that the non-linear system can be controlled and used in driving three-phase induction motor.

Optimal control of the gear shifting process for shift smoothness in dual-clutch transmissions

NASA Astrophysics Data System (ADS)

Li, Guoqiang; Görges, Daniel

2018-03-01

The control of the transmission system in vehicles is significant for the driving comfort. In order to design a controller for smooth shifting and comfortable driving, a dynamic model of a dual-clutch transmission is presented in this paper. A finite-time linear quadratic regulator is proposed for the optimal control of the two friction clutches in the torque phase for the upshift process. An integral linear quadratic regulator is introduced to regulate the relative speed difference between the engine and the slipping clutch under the optimization of the input torque during the inertia phase. The control objective focuses on smoothing the upshift process so as to improve the driving comfort. Considering the available sensors in vehicles for feedback control, an observer design is presented to track the immeasurable variables. Simulation results show that the jerk can be reduced both in the torque phase and inertia phase, indicating good shift performance. Furthermore, compared with conventional controllers for the upshift process, the proposed control method can reduce shift jerk and improve shift quality.

Influence of asymmetric magnetic perturbation on the nonlinear evolution of double tearing modes

NASA Astrophysics Data System (ADS)

Xiong, G. Z.; Wang, L.; Li, X. Q.; Liu, H. F.; Tang, C. J.; Huang, J.; Zhang, X.; Wang, X. Q.

2017-06-01

The effects of asymmetric magnetic perturbation on the triggering and evolution of double tearing modes (DTMs) are investigated using nonlinear magnetohydrodynamics simulations in a slab geometry. We find that for reversed magnetic shear plasmas the resistive reconnection process induced by the initial perturbation at one rational surface can drive a new island at the other rational surface with the same mode number. The four typical states of the mode for the time evolution are found, and include: (i) a linear growth stage; (ii) a linear/nonlinear stable stage; (iii) an interactively driving stage; and (iv) a symmetric DTM stage. These differ from previous simulation results. Moreover, nonlinear DTM growth is found to strongly depend on the asymmetric magnetic perturbation, particularly in the early nonlinear phase. The initial perturbation strength scale of island width suggests that the left island enters into a Sweet-Parker growth process when the right island is sufficiently large to effectively drive the other. These results predict that although externally applied magnetic perturbations can suppress the neoclassical tearing mode they can also trigger new instabilities such as asymmetric DTMs.

Electric propulsion using the permanent magnet synchronous motor without rotor position transducers

NASA Astrophysics Data System (ADS)

Batzel, Todd Douglas

The permanent magnet synchronous motor (PMSM) is increasingly playing an important role in electric propulsion systems due to its many advantages over competing technologies. For successful operation of the PMSM, rotor position and speed information is required. A resolver or encoder attached to the shaft of the machine usually provides this information. Many applications, however, cannot tolerate the use of the position sensor because of space and weight limitations, reliability concerns, or packaging issues. Thus, there has been an intense interest in the development of a so-called position sensorless drive, where the PMSM stator itself is used as the rotor position sensor. In this work, a sensorless electric drive is developed for various undersea propulsion applications, where the rotor position sensor is often undesirable due to the harsh operating environment as well as space and weight limitations. In this work, an observer is developed which enables sensorless operation of the PMSM over a wide speed range. In addition, a method is presented for estimating the standstill rotor angle, an operating condition at which the rotor position observers are typically ill conditioned. In this work two design methodologies are applied to the sensorless electric drive application, including a model-based and a neural network-based approach. Implementation issues for the sensorless electric drive are discussed, and experimental results are presented in order to demonstrate the effectiveness of the proposed techniques to the sensorless PMSM.

Examination of associations between risky driving behaviors and hazardous drinking among a sample of college students.

PubMed

Martin, Ryan J; Cox, Melissa J; Chaney, Beth H; Knowlden, Adam P

2018-06-21

Hazardous drinking is associated with other risky behaviors and negative health-related outcomes. This study examined co-variation between hazardous drinking scores and the following risky driving behaviors: falling asleep while driving, texting (receiving and sending) while driving, and driving after consuming alcohol. The participants in this study were a sample of undergraduate students (N = 1,298) who were enrolled in an introductory health course at a large, Southeastern university in Spring 2016 and completed an online health survey that assessed hazardous drinking, falling asleep while driving, texting while driving, and driving after consuming alcohol. We conducted a series of two-step regression analyses to examine co-variation between hazardous drinking scores (using the AUDIT-C) and the risky driving behaviors of interest. We found that the majority of participants did not drink and drive (91.8%) nor did they fall asleep while driving (80.4%); however, the majority did read a text while driving (81.7%) and sent a text while driving (75.3%). In the full multivariable model, hazardous drinking score was positively associated with drinking and driving (Step 2 OR = 1.28, 95% CI: 1.18, 1.38) and sending a text message while driving (Step 2 b = 0.19, p = .01). Hazardous drinking score was also positively associated with reading a text while driving (Step 1 b = 0.14, p<.001) and falling asleep while driving (Step 1 b = 0.02, p=.02) in the model only controlling for demographic characteristics. The analyses also indicated co-variability between the following risky driving behaviors: (1) drinking and driving/reading a text message while driving, (2) drinking and driving/falling asleep and driving, (3) reading a text while driving/sending a text while driving, and (4) sending a text while driving/sleeping and driving. The findings of this study indicate a need for interventions discouraging both hazardous drinking and risky driving behaviors in college student populations; recommendations to reduce risky driving and hazardous drinking are discussed.

Randomised prospective parallel trial of therapeutic versus subtherapeutic nasal continuous positive airway pressure on simulated steering performance in patients with obstructive sleep apnoea

PubMed Central

Hack, M.; Davies, R.; Mullins, R.; Choi, S. J.; Ramdassingh-Dow, S.; Jenkinson, C.; Stradling, J.

2000-01-01

BACKGROUND—Obstructive sleep apnoea (OSA) impairs vigilance and may lead to an increased rate of driving accidents. In uncontrolled studies accident rates and simulated steering performance improve following treatment with nasal continuous positive airway pressure (NCPAP). This study seeks to confirm the improvement in steering performance in a randomised controlled trial using subtherapeutic NCPAP as a control treatment.
METHODS—Fifty nine men with OSA (Epworth Sleepiness Score (ESS) of ⩾10, and ⩾10/h dips in SaO2 of >4% due to OSA) received therapeutic or subtherapeutic NCPAP (≈1 cm H2O) for one month. Simulated steering performance over three 30-minute "drives" was quantified as: standard deviation (SD) of road position, deterioration in SD across the drive, length of drive before "crashing", and number of off-road events. The reaction times to peripheral target stimuli during the drive were also measured.
RESULTS—Subtherapeutic NCPAP did not improve overnight >4% SaO2 dips/h compared with baseline values, thus acting as a control. The SD of the steering position improved from 0.36 to 0.21 on therapeutic NCPAP, and from 0.35 to 0.30 on subtherapeutic NCPAP (p = 0.03). Deterioration in SD of the steering position improved from 0.18to 0.06 SD/h with therapeutic NCPAP and worsened from 0.18 to 0.24 with subtherapeutic NCPAP (p = 0.04). The reaction time to target stimuli was quicker after therapeutic than after subtherapeutic NCPAP (2.3 versus 2.7 seconds, p = 0.04).
CONCLUSIONS—Therapeutic NCPAP improves steering performance and reaction time to target stimuli in patients with OSA, lending further support to the hypothesis that OSA impairs driving, increases driving accident rates, and that these improve following treatment with NCPAP.

 PMID:10679542

The relationship between attentional bias toward safety and driving behavior.

PubMed

Zheng, Tingting; Qu, Weina; Zhang, Kan; Ge, Yan

2016-11-01

As implicit cognitive processes garner more and more importance, studies in the fields of healthy psychology and organizational safety research have focused on attentional bias, a kind of selective allocation of attentional resources in the early stage of cognitive processing. However, few studies have explored the role of attentional bias on driving behavior. This study assessed drivers' attentional bias towards safety-related words (ABS) using the dot-probe paradigm and self-reported daily driving behaviors. The results revealed significant negative correlations between attentional bias scores and several indicators of dangerous driving. Drivers with fewer dangerous driving behaviors showed greater ABS. We also built a significant linear regression model between ABS and the total DDDI score, as well as ABS and the number of accidents. Finally, we discussed the possible mechanism underlying these associations and several limitations of our study. This study opens up a new topic for the exploration of implicit processes in driving safety research. Copyright © 2016 Elsevier Ltd. All rights reserved.

Research on Performance of Wire-controlled Hydraulic Steering System Based on Four-wheel Steering

NASA Astrophysics Data System (ADS)

Tao, P.; Jin, X. H.

2018-05-01

In this paper, the steering stability and control strategy of forklift are put forward. Drive based on yawing moment distribution of rotary torque coordination control method, through analyzing the linear two degree of freedom model of forklift truck, forklift yawing angular velocity and mass center side-slip Angle of expectations, as the control target parameters system, using fuzzy controller output driving forklift steering the yawing moment, to drive rotary torque distribution, make the forklift truck to drive horizontal pendulum angular velocity and side-slip Angle tracking reference model very well. In this paper, the lateral stability control system were designed, the joint simulation in MATLAB/Simulink, the simulation results show that under the different partial load, the control system can effectively to control side forklift lateral stability, enhanced the forklift driving safety, for the side forklift steering stability study provides a theoretical basis.

The emotional side of cognitive distraction: Implications for road safety.

PubMed

Chan, Michelle; Singhal, Anthony

2013-01-01

Driver distraction is estimated to be one of the leading causes of motor vehicle accidents. However, little is known about the role of emotional distraction on driving, despite evidence that attention is highly biased toward emotion. In the present study, we used a dual-task paradigm to examine the potential for driver distraction from emotional information presented on roadside billboards. This purpose was achieved using a driving simulator and three different types of emotional information: neutral words, negative emotional words, and positive emotional words. Participants also responded to target words while driving and completed a surprise free recall task of all the words at the end of the study. The findings suggest that driving performance is differentially affected by the valence (negative versus positive) of the emotional content. Drivers had lower mean speeds when there were emotional words compared to neutral words, and this slowing effect lasted longer when there were positive words. This may be due to distraction effects on driving behavior, which are greater for positive arousing stimuli. Moreover, when required to process non-emotional target stimuli, drivers had faster mean speeds in conditions where the targets were interspersed with emotional words compared to neutral words, and again, these effects lasted longer when there were positive words. On the other hand, negative information led to better memory recall. These unique effects may be due to separate processes in the human attention system, particularly related to arousal mechanisms and their interaction with emotion. We conclude that distraction that is emotion-based can modulate attention and decision-making abilities and have adverse impacts on driving behavior for several reasons. Copyright © 2012 Elsevier Ltd. All rights reserved.

Ion-trajectory analysis for micromotion minimization and the measurement of small forces

NASA Astrophysics Data System (ADS)

Gloger, Timm F.; Kaufmann, Peter; Kaufmann, Delia; Baig, M. Tanveer; Collath, Thomas; Johanning, Michael; Wunderlich, Christof

2015-10-01

For experiments with ions confined in a Paul trap, minimization of micromotion is often essential. In order to diagnose and compensate micromotion we have implemented a method that allows for finding the position of the radio-frequency (rf) null reliably and efficiently, in principle, without any variation of direct current (dc) voltages. We apply a trap modulation technique and focus-scanning imaging to extract three-dimensional ion positions for various rf drive powers and analyze the power dependence of the equilibrium position of the trapped ion. In contrast to commonly used methods, the search algorithm directly makes use of a physical effect as opposed to efficient numerical minimization in a high-dimensional parameter space. Using this method we achieve a compensation of the residual electric field that causes excess micromotion in the radial plane of a linear Paul trap down to 0.09 Vm-1 . Additionally, the precise position determination of a single harmonically trapped ion employed here can also be utilized for the detection of small forces. This is demonstrated by determining light pressure forces with a precision of 135 yN. As the method is based on imaging only, it can be applied to several ions simultaneously and is independent of laser direction and thus well suited to be used with, for example, surface-electrode traps.

Relationships between psychological state, abuse, somatization and visceral pain sensitivity in irritable bowel syndrome

PubMed Central

Grinsvall, Cecilia; Törnblom, Hans; Tack, Jan; Van Oudenhove, Lukas; Simrén, Magnus

2018-01-01

Background and objective Psychological states may interfere with visceral sensitivity. Here we investigate associations between psychosocial factors and visceral sensitivity in irritable bowel syndrome (IBS). Methods Two IBS patient cohorts (Cohort 1: n = 231, Rome II; Cohort 2: n = 141, Rome III) underwent rectal barostat testing, and completed questionnaires for anxiety, depression, somatization, and abuse. The associations between questionnaire measures and visceral sensitivity parameters were analyzed in three-step general linear models (step1: demographic and abuse variables; step 2: anxiety and depression; step 3: somatization). Results Cohort 1. Pain threshold was positively associated with age and female gender, and negatively with adult sexual abuse and somatization. Pain referral area was negatively associated with age and positively with somatization and GI-specific anxiety, the latter effect mediated by somatization. Cohort 2. Pain threshold was positively associated with age and male gender, and negatively with adult sexual abuse. Pain intensity ratings were positively associated with somatization, female gender and depression, the latter effect mediated by somatization. Conclusion Somatization is associated with most visceral sensitivity parameters, and mediates the effect of some psychological factors on visceral sensitivity. It may reflect a psychobiological sensitization process driving symptom generation in IBS. In addition, abuse history was found to independently affect some visceral sensitivity parameters. PMID:29511560

Equilibration of energy in slow–fast systems

PubMed Central

Shah, Kushal; Gelfreich, Vassili; Rom-Kedar, Vered

2017-01-01

Ergodicity is a fundamental requirement for a dynamical system to reach a state of statistical equilibrium. However, in systems with several characteristic timescales, the ergodicity of the fast subsystem impedes the equilibration of the whole system because of the presence of an adiabatic invariant. In this paper, we show that violation of ergodicity in the fast dynamics can drive the whole system to equilibrium. To show this principle, we investigate the dynamics of springy billiards, which are mechanical systems composed of a small particle bouncing elastically in a bounded domain, where one of the boundary walls has finite mass and is attached to a linear spring. Numerical simulations show that the springy billiard systems approach equilibrium at an exponential rate. However, in the limit of vanishing particle-to-wall mass ratio, the equilibration rates remain strictly positive only when the fast particle dynamics reveal two or more ergodic components for a range of wall positions. For this case, we show that the slow dynamics of the moving wall can be modeled by a random process. Numerical simulations of the corresponding springy billiards and their random models show equilibration with similar positive rates. PMID:29183966

Sensorless optimal sinusoidal brushless direct current for hard disk drives

NASA Astrophysics Data System (ADS)

Soh, C. S.; Bi, C.

2009-04-01

Initiated by the availability of digital signal processors and emergence of new applications, market demands for permanent magnet synchronous motors have been surging. As its back-emf is sinusoidal, the drive current should also be sinusoidal for reducing the torque ripple. However, in applications like hard disk drives, brushless direct current (BLDC) drive is adopted instead of sinusoidal drive for simplification. The adoption, however, comes at the expense of increased harmonics, losses, torque pulsations, and acoustics. In this paper, we propose a sensorless optimal sinusoidal BLDC drive. First and foremost, the derivation for an optimal sinusoidal drive is presented, and a power angle control scheme is proposed to achieve an optimal sinusoidal BLDC. The scheme maintains linear relationship between the motor speed and drive voltage. In an attempt to execute the sensorless drive, an innovative power angle measurement scheme is devised, which takes advantage of the freewheeling diodes and measures the power angle through the detection of diode voltage drops. The objectives as laid out will be presented and discussed in this paper, supported by derivations, simulations, and experimental results. The proposed scheme is straightforward, brings about the benefits of sensorless sinusoidal drive, negates the need for current sensors by utilizing the freewheeling diodes, and does not incur additional cost.

Behind the Wheel: Predictors of Driving Exposure in Older Drivers.

PubMed

Coxon, Kristy; Chevalier, Anna; Lo, Serigne; Ivers, Rebecca; Brown, Julie; Keay, Lisa

2015-06-01

To explore and deepen understanding of factors influencing driving exposure for older drivers. Cross-sectional. Baseline data on function and driving exposure from 1 week of driving were evaluated. A convenience sample of 380 drivers aged 75 and older, residing in northwest Sydney, was recruited. Participants were required to be the primary drivers of their own vehicle. Driver function was evaluated using the DriveSafe and DriveAware clinic-based assessments to measure visual attention to the driving environment and awareness of driving ability. Demographic information was obtained through interview. An in-vehicle monitoring device with data logger and GPS receiver, was used to measure driving exposure in 362 of 380 participants' vehicles. Driving exposure outcomes were total distance driven, furthest distance traveled from home, and average trip length. Factors influencing these exposure outcomes were analyzed using generalized linear regression. Drivers typically drove 100 km in local and surrounding areas during the week. Function was predictive of all driving exposure outcomes. Drivers with lower levels of function drove fewer kilometers and took shorter trips closer to home. Age, health status, and personal circumstance (e.g., rural residence) also influenced exposure, but sex did not. Using objective measures, this study provides evidence that function, age, health status, and personal circumstance influence driving exposure of older drivers. Understanding how older people use driving to preserve their independence is important for exploring safe driving strategies for older people. © 2015, Copyright the Authors Journal compilation © 2015, The American Geriatrics Society.

The Roles of Tectonics and Climate in Driving Erosion Rates in the Eastern Himalaya

NASA Astrophysics Data System (ADS)

Larsen, I. J.; Montgomery, D.; Stone, J. O.

2016-12-01

Landslide erosion governs the flux of sediment from non-glaciated mountains. Hence patterns in landslide erosion rates have the potential to reveal how such landscapes respond to spatially-varying climatic and tectonic forcing. Across strong spatial gradients in precipitation and exhumation rates in the eastern Himalaya, we mapped 27,611 landslides and measured 10Be in river sediment in a swath spanning from the Himalayan mountain front northward to the Yarlung Tsangpo Gorge. For the entire landscape, landslide erosion and 10Be-based denudation rates are not correlated with mean annual precipitation. However, erosion and denudation rates increase non-linearly as a function of mean hillslope angles, which is diagnostic of tectonic-driven landslide erosion on threshold hillslopes. Dividing the landscape into distinct geologic-tectonic terranes reveals that erosion rates scale positively with both mean hillslope angles and exhumation rates, but also that threshold topography has not developed throughout the region. Mean annual precipitation rates range from 0.5 to 3 m across the terranes, and erosion rates are highest in the relatively dry Yarlung Tsangpo Gorge, which receives 1.5 m of precipitation annually. However, for areas south of the Gorge, where moisture sources from the south first interact with the orographic barrier of the Himalaya, there is a modest linear increase in erosion rate with increasing mean annual rainfall. These results indicate that tectonics is the main control on spatial patterns of erosion in the eastern Himalaya, but that climate may play a modulating role. Hence the relative roles tectonics and climate play in driving erosion rates likely vary at the sub-orogen scale.

Self-locking telescoping manipulator arm

NASA Technical Reports Server (NTRS)

Nesmith, M. F. (Inventor)

1985-01-01

A telescoping manipulator arm and pivotable finger assembly are disclosed. The telescoping arm assembly includes a generally T-shaped arm having three outwardly extending fingers guided on grooved roller guides to compensate for environmental variations. The pivotable finger assembly includes four pivoting fingers. Arcuate teeth are formed on the ends of the fingers. A rack having teeth on four sides meshes with each one of the fingers. One surface of the rack includes teeth along its entire surface which mesh with teeth of one of the fingers. The teeth at the remote end of the rack engage teeth of a gear wheel. The wheel includes a worm which meshes with a worn drive shaft of the drive motor providing a ninety degree self-locking drive for locking the fingers in a desired position. A similar drive provides a self-locking drive for positioning the telescoping arm.

49 CFR 571.201 - Standard No. 201; Occupant protection in interior impact.

Code of Federal Regulations, 2013 CFR

2013-10-01

... seat. Ambulance means a motor vehicle designed exclusively for the purpose of emergency medical care... seats in their rearmost design driving position and reclinable forward seat backs in their nominal design driving position; (b) Direction of impact shall be either: (1) In a vertical plane parallel to the...

49 CFR 571.201 - Standard No. 201; Occupant protection in interior impact.

Code of Federal Regulations, 2014 CFR

2014-10-01

... seat. Ambulance means a motor vehicle designed exclusively for the purpose of emergency medical care... seats in their rearmost design driving position and reclinable forward seat backs in their nominal design driving position; (b) Direction of impact shall be either: (1) In a vertical plane parallel to the...

49 CFR 571.201 - Standard No. 201; Occupant protection in interior impact.

Code of Federal Regulations, 2012 CFR

2012-10-01

... seat. Ambulance means a motor vehicle designed exclusively for the purpose of emergency medical care... seats in their rearmost design driving position and reclinable forward seat backs in their nominal design driving position; (b) Direction of impact shall be either: (1) In a vertical plane parallel to the...

Effects of trait anger, driving anger, and driving experience on dangerous driving behavior: A moderated mediation analysis.

PubMed

Ge, Yan; Zhang, Qian; Zhao, Wenguo; Zhang, Kan; Qu, Weina

2017-11-01

To explore the effect of anger behind the wheel on driving behavior and accident involvement has been the subject of many studies. However, few studies have explored the interaction between anger and driving experience on dangerous driving behavior. This study is a moderated mediation analysis of the effect of trait anger, driving anger, and driving experience on driving behavior. A sample of 303 drivers was tested using the Trait Anger Scale (TAS), the Driving Anger Scale (DAS), and the Dula Dangerous Driving Index (DDDI). The results showed that trait anger and driving anger were positively correlated with dangerous driving behavior. Driving anger partially mediated the effect of trait anger on dangerous driving behavior. Driving experience moderated the relationship between trait anger and driving anger. It also moderated the effect of driving anger on dangerous driving behavior. These results suggest that drivers with more driving experience may be safer as they are not easily irritated during driving. © 2017 Wiley Periodicals, Inc.

Standing wave contributions to the linear interference effect in stratosphere-troposphere coupling

NASA Astrophysics Data System (ADS)

Watt-Meyer, Oliver; Kushner, Paul

2014-05-01

A body of literature by Hayashi and others [Hayashi 1973, 1977, 1979; Pratt, 1976] developed a decomposition of the wavenumber-frequency spectrum into standing and travelling waves. These techniques directly decompose the power spectrum—that is, the amplitudes squared—into standing and travelling parts. This, incorrectly, does not allow for a term representing the covariance between these waves. We propose a simple decomposition based on the 2D Fourier transform which allows one to directly compute the variance of the standing and travelling waves, as well as the covariance between them. Applying this decomposition to geopotential height anomalies in the Northern Hemisphere winter, we show the dominance of standing waves for planetary wavenumbers 1 through 3, especially in the stratosphere, and that wave-1 anomalies have a significant westward travelling component in the high-latitude (60N to 80N) troposphere. Variations in the relative zonal phasing between a wave anomaly and the background climatological wave pattern—the "linear interference" effect—are known to explain a large part of the planetary wave driving of the polar stratosphere in both hemispheres. While the linear interference effect is robust across observations, models of varying degrees of complexity, and in response to various types of perturbations, it is not well understood dynamically. We use the above-described decomposition into standing and travelling waves to investigate the drivers of linear interference. We find that the linear part of the wave activity flux is primarily driven by the standing waves, at all vertical levels. This can be understood by noting that the longitudinal positions of the antinodes of the standing waves are typically close to being aligned with the maximum and minimum of the background climatology. We discuss implications for predictability of wave activity flux, and hence polar vortex strength variability.

Impact of a New Law to Reduce the Legal Blood Alcohol Concentration Limit - A Poisson Regression Analysis and Descriptive Approach.

PubMed

Nistal-Nuño, Beatriz

2017-03-31

In Chile, a new law introduced in March 2012 lowered the blood alcohol concentration (BAC) limit for impaired drivers from 0.1% to 0.08% and the BAC limit for driving under the influence of alcohol from 0.05% to 0.03%, but its effectiveness remains uncertain. The goal of this investigation was to evaluate the effects of this enactment on road traffic injuries and fatalities in Chile. A retrospective cohort study. Data were analyzed using a descriptive and a Generalized Linear Models approach, type of Poisson regression, to analyze deaths and injuries in a series of additive Log-Linear Models accounting for the effects of law implementation, month influence, a linear time trend and population exposure. A review of national databases in Chile was conducted from 2003 to 2014 to evaluate the monthly rates of traffic fatalities and injuries associated to alcohol and in total. It was observed a decrease by 28.1 percent in the monthly rate of traffic fatalities related to alcohol as compared to before the law (P<0.001). Adding a linear time trend as a predictor, the decrease was by 20.9 percent (P<0.001).There was a reduction in the monthly rate of traffic injuries related to alcohol by 10.5 percent as compared to before the law (P<0.001). Adding a linear time trend as a predictor, the decrease was by 24.8 percent (P<0.001). Positive results followed from this new 'zero-tolerance' law implemented in 2012 in Chile. Chile experienced a significant reduction in alcohol-related traffic fatalities and injuries, being a successful public health intervention.

Personality and attitudes as predictors of risky driving among older drivers.

PubMed

Lucidi, Fabio; Mallia, Luca; Lazuras, Lambros; Violani, Cristiano

2014-11-01

Although there are several studies on the effects of personality and attitudes on risky driving among young drivers, related research in older drivers is scarce. The present study assessed a model of personality-attitudes-risky driving in a large sample of active older drivers. A cross-sectional design was used, and structured and anonymous questionnaires were completed by 485 older Italian drivers (Mean age=68.1, SD=6.2, 61.2% males). The measures included personality traits, attitudes toward traffic safety, risky driving (errors, lapses, and traffic violations), and self-reported crash involvement and number of issued traffic tickets in the last 12 months. Structural equation modeling showed that personality traits predicted both directly and indirectly traffic violations, errors, and lapses. More positive attitudes toward traffic safety negatively predicted risky driving. In turn, risky driving was positively related to self-reported crash involvement and higher number of issued traffic tickets. Our findings suggest that theoretical models developed to account for risky driving of younger drivers may also apply in the older drivers, and accordingly be used to inform safe driving interventions for this age group. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of Armodafinil on Simulated Driving and Self-Report Measures in Obstructive Sleep Apnea Patients prior to Treatment with Continuous Positive Airway Pressure

PubMed Central

Kay, Gary G.; Feldman, Neil

2013-01-01

Study Objectives: Obstructive sleep apnea (OSA) has been associated with an increased risk of motor vehicle crashes. This driving risk can be reduced (≥ 50%) by treatment with continuous positive airway pressure (CPAP). However residual excessive daytime sleepiness (EDS) can persist for some patients who regularly use CPAP. The current study was designed to assess the effect of armodafinil on simulated driving performance and subsequent CPAP treatment compliance in newly diagnosed OSA patients with EDS during a 2-week “waiting period” prior to initiation of CPAP. Methods: Sixty-nine newly diagnosed OSA patients, awaiting CPAP therapy, were randomized (1:1) to placebo or armodafinil (150 mg/day) treatment. Simulated driving tests and self-report measures were completed at baseline, after 2 weeks of drug treatment, and following 6 weeks of CPAP treatment. CPAP compliance was evaluated at the end of 6 weeks of CPAP. Results: Compared to placebo, armodafinil improved simulated driving safety performance in OSA patients awaiting CPAP therapy (p = 0.03). Improvement was seen in lane position deviation (p = 0.002) and number of lane excursions (p = 0.02). Improvement was also observed on measures of sleepiness using the Epworth Sleepiness Scale (ESS) and sleep related quality of life. Following 6 weeks of CPAP, there was also significant improvement observed on multiple measures of simulated driving performance. CPAP compliance did not differ between armodafinil-treated and placebo-treated patients (p = 0.80). Conclusions: Armodafinil was found to improve simulated driving performance in OSA patients with EDS prior to initiation of CPAP. Treatment with armodafinil showed no effect on subsequent CPAP compliance. Citation: Kay GG; Feldman N. Effects of armodafinil on simulated driving and self-report measures in obstructive sleep apnea patients prior to treatment with continuous positive airway pressure. J Clin Sleep Med 2013;9(5):445-454. PMID:23674935

The effects of medical marijuana laws on cannabis-involved driving.

PubMed

Sevigny, Eric L

2018-06-06

This study uses data from the Fatality Analysis Reporting System and a differences-in-differences model to examine the effect of state medical marijuana laws (MMLs) on cannabis-involved driving among U.S. drivers involved in a fatal crash between 1993-2014. Findings indicate that MMLs in general have a null effect on cannabis-positive driving, as do state laws with specific supply provisions including home cultivation and unlicensed or quasi-legal dispensaries. Only in jurisdictions with state-licensed medical marijuana dispensaries did the odds of marijuana-involved driving increase significantly by 14 percent, translating into an additional 87 to 113 drivers testing positive for marijuana per year. Sensitivity analyses reveal these findings to be generally robust to alternate specifications, although an observed spillover effect consistent with elevated drugged driving enforcement in bordering states weakens a causal interpretation. Still, reasonable policy implications are drawn regarding drugged driving prevention/enforcement and regulations governing dispensary delivery services and business siting decisions. Copyright © 2018 Elsevier Ltd. All rights reserved.

Street racing video games and risk-taking driving: An Internet survey of automobile enthusiasts.

PubMed

Vingilis, Evelyn; Seeley, Jane; Wiesenthal, David L; Wickens, Christine M; Fischer, Peter; Mann, Robert E

2013-01-01

The purpose of this study was to examine the relationships among risky driving attitudes, self-perceptions as a risky driver, playing of "drive'em up" (which rewarded players for frequent traffic and other violations) and "circuit" racing video games as well as self-reported risky driving through a web-based survey of car and racing club members in relation to a socio-cognitive model of the effects of racing video game playing. An Internet questionnaire was developed and included: (1) self-perceptions as a risky driver scales (Driver Thrill Seeking and Competitive Attitude Toward Driving); (2) attitudes regarding street racing; (3) street racing video game playing, and (4) self-reported risky driving (Risk-Taking Driving Scale). A sequential logistic regression was performed entering age and driving exposure as control variables in the first block, self-perceptions as a risky driver in the second block, attitudes in the third block and playing "drive'em up" and "circuit" racing games in the last block to examine their effects on self-reported risk-taking driving. A total of 503 survey respondents were included in the analyses and only 20% reported any risk-taking driving. Higher score on the Competitive Attitude Toward Driving Scale, more positive attitudes toward street racing, and more frequent reported playing of "drive'em up" video games were associated with higher odds on the self-reported Risk-Taking Driving Scale. However, the Driver Thrill Seeking Scale and "circuit" video game playing failed to predict self-reported risk-taking driving. Self-perceptions as a risky driver, positive attitudes toward risky driving and "drive'em up" street-racing games, but not "circuit" racing games, are associated with increased risk-taking driving. These findings are congruent with experimental studies in which games that reward driving violations increased risk taking, suggesting that risk taking may be a function of type of street racing game played by affecting self-perceptions as a risky driver. Copyright © 2012 Elsevier Ltd. All rights reserved.

PHOTOELECTRIC CONTROL FOR TAPE POSITIONING

DOEpatents

Woody, J.W. Jr.

1961-07-25

A control system is described for producing control impulses which may be used to start, stop, and position a magnetic tape with respect to a transducer, and to locate discrete areas on the tape. Means are provided for positive identification of data blocks, exact positioning of the tape under the magnetic head, drive in either direction, accurate skip-over of imperfect regions of the tape, stopping the tape if equipment malfunction results in a failure to detect the block-identifying signals, and starting and stopping those parts of the tape between of the tape drive clutches.

Experimental investigation of mode transitions in asymmetric capacitively coupled radio-frequency Ne and CF4 plasmas

NASA Astrophysics Data System (ADS)

Liu, Gang-Hu; Liu, Yong-Xin; Bai, Li-Shui; Zhao, Kai; Wang, You-Nian

2018-02-01

The dependence of the electron density and the emission intensity on external parameters during the transitions of the electron power absorption mode is experimentally studied in asymmetric electropositive (neon) and electronegative (CF4) capacitively coupled radio-frequency plasmas. The spatio-temporal distribution of the emission intensity is measured with phase resolved optical emission spectroscopy and the electron density at the discharge center is measured by utilizing a floating hairpin probe. In neon discharge, the emission intensity increases almost linearly with the rf voltage at all driving frequencies covered here, while the variation of the electron density with the rf voltage behaves differently at different driving frequencies. In particular, the electron density increases linearly with the rf voltage at high driving frequencies, while at low driving frequencies the electron density increases slowly at the low-voltage side and, however, grows rapidly, when the rf voltage is higher than a certain value, indicating a transition from α to γ mode. The rf voltage, at which the mode transition occurs, increases with the decrease of the driving frequency/the working pressure. By contrast, in CF4 discharge, three different electron power absorption modes can be observed and the electron density and emission intensity do not exhibit a simple dependence on the rf voltage. In particular, the electron density exhibits a minimum at a certain rf voltage when the electron power absorption mode is switching from drift-ambipolar to the α/γ mode. A minimum can also be found in the emission intensity at a higher rf voltage when a discharge is switching into the γ mode.

Advances in traction drive technology

NASA Technical Reports Server (NTRS)

Loewenthal, S. H.; Anderson, N. E.; Rohn, D. A.

1983-01-01

Traction drives are traced from early uses as main transmissions in automobiles at the turn of the century to modern, high-powered traction drives capable of transmitting hundreds of horsepower. Recent advances in technology are described which enable today's traction drive to be a serious candidate for off-highway vehicles and helicopter applications. Improvements in materials, traction fluids, design techniques, power loss and life prediction methods will be highlighted. Performance characteristics of the Nasvytis fixed-ratio drive are given. Promising future drive applications, such as helicopter main transmissions and servo-control positioning mechanisms are also addressed.

An Examination of Four Successes in the Coast Guard’s Innovation Program and Implications for Innovation within Homeland Security

DTIC Science & Technology

2008-03-01

patterns, determine positive directions, and rapidly drive process improvements. This thesis examines literature related to leadership, strategic...an effective mechanism to sense emerging patterns, determine positive directions, and rapidly drive process improvements. This thesis examines...VESSEL SIGHTING APPLICATION - MISLE LITE .............................42 B. RUGGEDIZED TABLET COMPUTER

77 FR 51610 - Distracted Driving Grant Program

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-24

... include a global navigation satellite system receiver used for positioning, emergency notification, or.... (2) Prohibition on youth cell phone use while driving. The State statute must-- (a) Prohibit a driver... of texting or using a cell phone while driving; (2) for traffic signs that notify drivers about the...

Health-related quality of life among drug-naïve patients with narcolepsy with cataplexy, narcolepsy without cataplexy, and idiopathic hypersomnia without long sleep time.

PubMed

Ozaki, Akiko; Inoue, Yuichi; Nakajima, Toru; Hayashida, Kenichi; Honda, Makoto; Komada, Yoko; Takahashi, Kiyohisa

2008-12-15

To evaluate the health-related quality life (HRQOL) of drug-naïve patients with narcolepsy with cataplexy (NAwith CA), narcolepsy without cataplexy (NA without CA) and idiopathic hypersomnia without long sleep time (IHS without LST), and to explore the factors influencing the HRQOL. Factors associated with the occurrence of automobile accidents are also discussed. A total of 137 consecutive drug naïve patients who met the criteria of the 2nd edition of the International Classification of Sleep Disorders (NA with CA, n = 28; NA without CA, n = 27; IHS without LST, n = 82) were enrolled. The patients were asked to fill out questionnaires, including the SF-36, Epworth Sleepiness Scale (ESS), sociodemographic variables, and items regarding driving habits and the experiences related to automobile accidents. All 3 diagnostic groups had significantly lower scores in most SF-36 domains compared with Japanese normative data. Significant differences among the 3 diagnostic groups were not observed. Specific factors in SF-36 domains were not found with multiple linear regression analyses, while disease duration was positively correlated with mental health among all subjects. Among the patients reporting driving habits, ESS score (> or =16) was positively associated with the experience of automobile accidents. Our results indicated that HRQOL decreases in drug-naïve patients with hypersomnia, but neither disease category nor severity of the disorder appears as an associated factor. Increased severity of hypersomnia, however, was thought to play an important role in the occurrence of automobile accidents.

Responses to negative pressure surrounding the neck in anesthetized animals.

PubMed

Wolin, A D; Strohl, K P; Acree, B N; Fouke, J M

1990-01-01

Continuous positive pressure applied at the nose has been shown to cause a decrease in upper airway resistance. The present study was designed to determine whether a similar positive transmural pressure gradient, generated by applying a negative pressure at the body surface around the neck, altered upper airway patency. Studies were performed in nine spontaneously breathing anesthetized supine dogs. Airflow was measured with a pneumotachograph mounted on an airtight muzzle placed over the nose and mouth of each animal. Upper airway pressure was measured as the differential pressure between the extrathoracic trachea and the inside of the muzzle. Upper airway resistance was monitored as an index of airway patency. Negative pressure (-2 to -20 cmH2O) was applied around the neck by using a cuirass extending from the jaw to the thorax. In each animal, increasingly negative pressures were transmitted to the airway wall in a progressive, although not linear, fashion. Decreasing the pressure produced a progressive fall in upper airway resistance, without causing a significant change in respiratory drive or respiratory timing. At -5 cmH2O pressure, there occurred a significant fall in upper airway resistance, comparable with the response of a single, intravenous injection of sodium cyanide (0.5-3.0 mg), a respiratory stimulant that produces substantial increases in respiratory drive. We conclude that upper airway resistance is influenced by the transmural pressure across the airway wall and that such a gradient can be accomplished by making the extraluminal pressure more negative.(ABSTRACT TRUNCATED AT 250 WORDS)

Police custody following drink-driving: a prospective study.

PubMed

Lepresle, Aude; Mahindhoratep, Tiao Saysouda; Chiadmi, Fouad; Schlatter, Joël; Boraud, Cyril; Chariot, Patrick

2012-11-01

Drink-driving is a crime and traffic offences are a common cause of detention in police custody. Legal assessment of alcohol intoxication is based on breath or blood testing. We hypothesize that refusal of breath alcohol testing or inability to perform it can correspond to singular medical characteristics of the detainee, possibly assaulted or injured during the arrest. Our objective was to determine medical characteristics of detainees held in custody for drink-driving. Prospective monocentric study (April-October, 2010) of drink-drive arrestees. Controls were persons aged over 18 detained for other reasons than drink-driving. Data collected concerned persons' characteristics and reported assaults or observed injuries. 223 drivers were tested positive for breath alcohol level and 55 suspected drink-drivers refused or were not able to complete breath test. 2212 consecutively examined persons served as controls. Drink-drive arrestees requested medical examination more rarely (18% and 7%, vs. 43%, P<0.0001) and drivers tested positive for breath alcohol were more frequently alcohol abusers (25% vs. 14%, P<0.0001) than controls. Drivers who did not complete breath test more often reported assaults than those tested positive for breath alcohol (22% vs. 8%, P=0.007). They had more frequent traumatic injuries than those tested positive and than controls (29% vs. 11% and 17%, P=0.003 and 0.02). Only 1% of drink drivers were unfit for detention after medical examination. Physicians need to give attentive care to detained drink-drivers. Special attention should be paid to drink-drivers who refused or were not able to complete breath alcohol measurement. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Can "the voices in the car" persuade drivers to go green?: effects of benefit appeals from in-vehicle voice agents and the role of drivers' affective states on eco-driving.

PubMed

Joo, Yeon Kyoung; Lee, Jong-Eun Roselyn

2014-04-01

The present research investigated the possibility of using an in-vehicle voice agent to promote eco-driving. Considering that both types of benefit appeals--egoistic (emphasizing benefits to the self) and altruistic (emphasizing benefits to others)--could be employed to promote eco-driving behavior, we explored the effects of benefit appeals delivered by an in-vehicle voice agent on driving performance. In particular, we tested whether and how the valence (positive vs. negative) of drivers' affective states moderates the effects, drawing on the functionalist affect-cognition framework, which has theorized that positive affect leads people to focus more on self-interest, whereas negative affect leads people to become more sensitive to social norms. An experiment was conducted in which participants, after undergoing affect (happy vs. sad) elicitation, received messages (egoistic vs. altruistic) promoting eco-driving from an in-vehicle voice agent while performing a simulated driving task. Results were partially consistent with the functionalist affect-cognition framework. Happy participants performed better on eco-driving when they were exposed to egoistic appeals than to altruistic appeals. On the other hand, the driving performance data from sad participants did not yield a significant difference between the egoistic condition and the altruistic condition. Participants' driving performance data further revealed that the joint effects of benefit appeals and affective states on safe driving performance mirrored the joint effects on eco-driving performance, confirming a close relationship between the two driving behaviors. Theoretical and practical implications for the use of in-vehicle voice agents and benefit appeals in promoting eco-driving and safe driving are discussed.

Tobacco and the Movies

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

Glantz, Stanton

The principal aim of this roadmap is to place the US and Fermilab in the best position to host the International Linear Collider (ILC). The strategy must be resilient against the many vicissitudes that will attend the development of such a large project. Pier Oddone will explore the tension between the needed concentration of effort to move a project as large as the ILC forward and the need to maintain the breadth of our field. America's leading health organizations agree. Smoking on screen is the #1 recruiter of new adolescent smokers in the United States - 390,000 kids a year,more » of whom 120,000 will die from tobacco-caused diseases. That's more Americans than die from drunk driving, criminal violence, illicit drugs, and HIV/AIDS combined. Why does Hollywood still promote smoking? Is it corrupt? Or stupid?« less

Start-up and control method and apparatus for resonant free piston Stirling engine

DOEpatents

Walsh, Michael M.

1984-01-01

A resonant free-piston Stirling engine having a new and improved start-up and control method and system. A displacer linear electrodynamic machine is provided having an armature secured to and movable with the displacer and having a stator supported by the Stirling engine housing in juxtaposition to the armature. A control excitation circuit is provided for electrically exciting the displacer linear electrodynamic machine with electrical excitation signals having substantially the same frequency as the desired frequency of operation of the Stirling engine. The excitation control circuit is designed so that it selectively and controllably causes the displacer electrodynamic machine to function either as a generator load to extract power from the displacer or the control circuit selectively can be operated to cause the displacer electrodynamic machine to operate as an electric drive motor to apply additional input power to the displacer in addition to the thermodynamic power feedback to the displacer whereby the displacer linear electrodynamic machine also is used in the electric drive motor mode as a means for initially starting the resonant free-piston Stirling engine.

Performance and reliability enhancement of linear coolers

NASA Astrophysics Data System (ADS)

Mai, M.; Rühlich, I.; Schreiter, A.; Zehner, S.

2010-04-01

Highest efficiency states a crucial requirement for modern tactical IR cryocooling systems. For enhancement of overall efficiency, AIM cryocooler designs where reassessed considering all relevant loss mechanisms and associated components. Performed investigation was based on state-of-the-art simulation software featuring magnet circuitry analysis as well as computational fluid dynamics (CFD) to realistically replicate thermodynamic interactions. As a result, an improved design for AIM linear coolers could be derived. This paper gives an overview on performance enhancement activities and major results. An additional key-requirement for cryocoolers is reliability. In recent time, AIM has introduced linear coolers with full Flexure Bearing suspension on both ends of the driving mechanism incorporating Moving Magnet piston drive. In conjunction with a Pulse-Tube coldfinger these coolers are capable of meeting MTTF's (Mean Time To Failure) in excess of 50,000 hours offering superior reliability for space applications. Ongoing development also focuses on reliability enhancement, deriving space technology into tactical solutions combining both, excelling specific performance with space like reliability. Concerned publication will summarize the progress of this reliability program and give further prospect.

Design and experiments of a linear piezoelectric motor driven by a single mode.

PubMed

Liu, Zhen; Yao, Zhiyuan; Li, Xiang; Fu, Qianwei

2016-11-01

In this contribution, we propose a novel linear piezoelectric motor with a compact stator that is driven by a single mode. The linear piezoelectric motor can realize bidirectional motion by changing the vibration modes of the stator. Finite element analysis is performed to determine the required vibration mode of the stator and obtain the optimal stator structure and dimensions. Furthermore, the trajectories of the driving foot are analyzed with and without consideration of the mechanical contact with the slider. It is shown that the trajectory of the driving foot is an oblique line when disregarding the contact, and the trajectory becomes an oblique ellipse while taking into account the contact. Finally, a prototype of the motor is fabricated based on the results of finite element analysis. The optimization results show that the motor reaches its maximum thrust force of 4.0 kg, maximum thrust-weight ratio of 33.3, maximum unloaded velocity of 385 mm/s under the excitation of Mode-B, and maximum unloaded velocity of 315 mm/s under the excitation of Mode-L.

Assessment of quasi-linear effect of RF power spectrum for enabling lower hybrid current drive in reactor plasmas

NASA Astrophysics Data System (ADS)

Cesario, Roberto; Cardinali, Alessandro; Castaldo, Carmine; Amicucci, Luca; Ceccuzzi, Silvio; Galli, Alessandro; Napoli, Francesco; Panaccione, Luigi; Santini, Franco; Schettini, Giuseppe; Tuccillo, Angelo Antonio

2017-10-01

The main research on the energy from thermonuclear fusion uses deuterium plasmas magnetically trapped in toroidal devices. To suppress the turbulent eddies that impair thermal insulation and pressure tight of the plasma, current drive (CD) is necessary, but tools envisaged so far are unable accomplishing this task while efficiently and flexibly matching the natural current profiles self-generated at large radii of the plasma column [1-5]. The lower hybrid current drive (LHCD) [6] can satisfy this important need of a reactor [1], but the LHCD system has been unexpectedly mothballed on JET. The problematic extrapolation of the LHCD tool at reactor graded high values of, respectively, density and temperatures of plasma has been now solved. The high density problem is solved by the FTU (Frascati Tokamak Upgrade) method [7], and solution of the high temperature one is presented here. Model results based on quasi-linear (QL) theory evidence the capability, w.r.t linear theory, of suitable operating parameters of reducing the wave damping in hot reactor plasmas. Namely, using higher RF power densities [8], or a narrower antenna power spectrum in refractive index [9,10], the obstacle for LHCD represented by too high temperature of reactor plasmas should be overcome. The former method cannot be used for routinely, safe antenna operations, Thus, only the latter key is really exploitable in a reactor. The proposed solutions are ultimately necessary for viability of an economic reactor.

Internalization of the ultra-thin ideal: positive implicit associations with underweight fashion models are associated with drive for thinness in young women.

PubMed

Ahern, Amy L; Bennett, Kate M; Hetherington, Marion M

2008-01-01

This study examined whether young women who make implicit associations between underweight models and positive attributes report elevated eating disorder symptoms. Ninety nine female undergraduates completed a weight based implicit association test (IAT) and self report measures of body dissatisfaction, thin-ideal internalization and eating disorder symptoms. IAT scores were associated with drive for thinness (r = -0.26, p < 0.05). This relationship was moderated by attitude importance. The relationship between drive for thinness and IAT scores was stronger (r = 0.34; p < 0.02) in participants who report that the media is an important source of information about fashion and being attractive. The IAT used in the current study is sensitive enough to discriminate between participants on drive for thinness. Women who have developed cognitive schemas that associate being underweight with positive attributes report higher eating disorder symptoms. Attitude importance is highlighted as a key construct in thin ideal internalization.

Research regarding stiffness optimization of wires used for joints actuation from an elephant's trunk robotic arm

NASA Astrophysics Data System (ADS)

Ciofu, C.; Stan, G.

2016-11-01

Elephant's trunk robotic arms driven by wires and pulley mechanisms have issues with wires stiffness because of the entailed elastic deformations that is causing errors of positioning. Static and dynamic loads from each joint of the robotic arm affect the stiffness of driving wires and precision positioning. The influence of wires elastic deformation on precision positioning decreases with the increasing of wires stiffness by using different pre-tensioning devices. In this paper, we analyze the variation of driving wires stiffness particularly to each wire driven joint. We obtain optimum wires stiffness variation by using an analytical method that highlights the efficiency of pre-tensioning mechanism. The analysis of driving wires stiffness is necessary for taking appropriate optimization measures of robotic arm dynamic behavior and, thus, for decreasing positioning errors of the elephant's trunk robotic arm with inner actuation through wires/cables.

Driving behavior recognition using EEG data from a simulated car-following experiment.

PubMed

Yang, Liu; Ma, Rui; Zhang, H Michael; Guan, Wei; Jiang, Shixiong

2018-07-01

Driving behavior recognition is the foundation of driver assistance systems, with potential applications in automated driving systems. Most prevailing studies have used subjective questionnaire data and objective driving data to classify driving behaviors, while few studies have used physiological signals such as electroencephalography (EEG) to gather data. To bridge this gap, this paper proposes a two-layer learning method for driving behavior recognition using EEG data. A simulated car-following driving experiment was designed and conducted to simultaneously collect data on the driving behaviors and EEG data of drivers. The proposed learning method consists of two layers. In Layer I, two-dimensional driving behavior features representing driving style and stability were selected and extracted from raw driving behavior data using K-means and support vector machine recursive feature elimination. Five groups of driving behaviors were classified based on these two-dimensional driving behavior features. In Layer II, the classification results from Layer I were utilized as inputs to generate a k-Nearest-Neighbor classifier identifying driving behavior groups using EEG data. Using independent component analysis, a fast Fourier transformation, and linear discriminant analysis sequentially, the raw EEG signals were processed to extract two core EEG features. Classifier performance was enhanced using the adaptive synthetic sampling approach. A leave-one-subject-out cross validation was conducted. The results showed that the average classification accuracy for all tested traffic states was 69.5% and the highest accuracy reached 83.5%, suggesting a significant correlation between EEG patterns and car-following behavior. Copyright © 2017 Elsevier Ltd. All rights reserved.

Unsteady Flow Simulation: A Numerical Challenge

DTIC Science & Technology

2003-03-01

drive to convergence the numerical unsteady term. The time marching procedure is based on the approximate implicit Newton method for systems of non...computed through analytical derivatives of S. The linear system stemming from equation (3) is solved at each integration step by the same iterative method...significant reduction of memory usage, thanks to the reduced dimensions of the linear system matrix during the implicit marching of the solution. The

Nonlinear gyrotropic motion of skyrmion in a magnetic nanodisk

NASA Astrophysics Data System (ADS)

Chen, Yi-fu; Li, Zhi-xiong; Zhou, Zhen-wei; Xia, Qing-lin; Nie, Yao-zhuang; Guo, Guang-hua

2018-07-01

We study the nonlinear gyrotropic motion of a magnetic skyrmion in a nanodisk by means of micromagnetic simulations. The skyrmion is driven by a linearly polarized harmonic field with the frequency of counterclockwise gyrotropic mode. It is found that the motion of the skyrmion displays different patterns with increasing field amplitude. In the linear regime of weak driving field, the skyrmion performs a single counterclockwise gyrotropic motion. The guiding center of the skyrmion moves along a helical line from the centre of the nanodisk to a stable circular orbit. The stable orbital radius increases linearly with the field amplitude. When the driving field is larger than a critical value, the skyrmion exhibits complex nonlinear motion. With the advance of time, the motion trajectory of the skyrmion goes through a series of evolution process, from a single circular motion to a bird nest-like and a flower-like trajectory and finally, to a gear-like steady-state motion. The frequency spectra show that except the counterclockwise gyrotropic mode, the clockwise gyrotropic mode is also nonlinearly excited and its amplitude increases with time. The complex motion trajectory of the skyrmion is the result of superposition of the two gyrotropic motions with changing amplitude. Both the linear and nonlinear gyrotropic motions of the skyrmion can be well described by a generalized Thiele's equation of motion.

Modular injector integrated linear apparatus with motion profile optimization for spatial atomic layer deposition.

PubMed

Wang, Xiaolei; Li, Yun; Lin, Jilong; Shan, Bin; Chen, Rong

2017-11-01

A spatial atomic layer deposition apparatus integrated with a modular injector and a linear motor has been designed. It consists of four parts: a precursor delivery manifold, a modular injector, a reaction zone, and a driving unit. An injector with multi-layer structured channels is designed to help improve precursor distribution homogeneity. During the back and forth movement of the substrate at high speed, the inertial impact caused by jerk and sudden changes of acceleration will degrade the film deposition quality. Such residual vibration caused by inertial impact will aggravate the fluctuation of the gap distance between the injector and the substrate in the deposition process. Thus, an S-curve motion profile is implemented to reduce the large inertial impact, and the maximum position error could be reduced by 84%. The microstructure of the film under the S-curve motion profile shows smaller root-mean-square and scanning voltage amplitude under an atomic force microscope, which verifies the effectiveness of the S-curve motion profile in reducing the residual vibration and stabilizing the gap distance between the injector and the substrate. The film deposition rate could reach 100 nm/min while maintaining good uniformity without obvious periodic patterns on the surface.

Modular injector integrated linear apparatus with motion profile optimization for spatial atomic layer deposition

NASA Astrophysics Data System (ADS)

Wang, Xiaolei; Li, Yun; Lin, Jilong; Shan, Bin; Chen, Rong

2017-11-01

A spatial atomic layer deposition apparatus integrated with a modular injector and a linear motor has been designed. It consists of four parts: a precursor delivery manifold, a modular injector, a reaction zone, and a driving unit. An injector with multi-layer structured channels is designed to help improve precursor distribution homogeneity. During the back and forth movement of the substrate at high speed, the inertial impact caused by jerk and sudden changes of acceleration will degrade the film deposition quality. Such residual vibration caused by inertial impact will aggravate the fluctuation of the gap distance between the injector and the substrate in the deposition process. Thus, an S-curve motion profile is implemented to reduce the large inertial impact, and the maximum position error could be reduced by 84%. The microstructure of the film under the S-curve motion profile shows smaller root-mean-square and scanning voltage amplitude under an atomic force microscope, which verifies the effectiveness of the S-curve motion profile in reducing the residual vibration and stabilizing the gap distance between the injector and the substrate. The film deposition rate could reach 100 nm/min while maintaining good uniformity without obvious periodic patterns on the surface.

Evidence for trivial Berry phase and absence of chiral anomaly in semimetal NbP

NASA Astrophysics Data System (ADS)

Sudesh; Kumar, Pawan; Neha, Prakriti; Das, Tanmoy; Patnaik, Satyabrata

2017-04-01

The discovery of Weyl semimetals (WSM) has brought forth the condensed matter realization of Weyl fermions, which were previously theorized as low energy excitations in high energy particle physics. Recently, transition metal mono-pnictides are under intense investigation for understanding properties of inversion-symmetry broken Weyl semimetals. Non-trivial Berry phase and chirality are important markers for characterizing topological aspects of Weyl semimetals. Most recently, theoretical calculations predict strong influence of the position of Weyl nodes with respect to Fermi surface and weak disorder that can drive WSMs into chirally symmetric Dirac semimetals. Using magneto-transport measurements in single crystals of WSM NbP, we observe an exceptionally large magnetoresistance at low temperature, which is non-saturating and linear at high fields. The origin of linear transverse magnetoresistance is assigned to charge carrier mobility fluctuations. Negative longitudinal magnetoresistance is not seen, suggesting lack of well-defined chiral anomaly in NbP. Unambiguous Shubnikov-de Haas oscillations are observed at low temperatures that are correlated to a trivial Berry phase corresponding to Fermi surface extrema at 30.5 Tesla. Our results are important towards identifying topological characteristics of Weyl semimetals and their experimental manifestations in the presence of weak disorder.

Novel Structures of Self-Associating Stapled Peptides

PubMed Central

Bhattacharya, Shibani; Zhang, Hongtao; Cowburn, David; Debnath, Asim K.

2012-01-01

Hydrocarbon stapling of peptides is a powerful technique to transform linear peptides into cell-permeable helical structures that can bind to specific biological targets. In this study, we have used high resolution solution NMR techniques complemented by Dynamic Light Scattering to characterize extensively a family of hydrocarbon stapled peptides with known inhibitory activity against HIV-1 capsid assembly to evaluate the various factors that modulate activity. The helical peptides share a common binding motif but differ in charge, the length and position of the staple. An important outcome of the study was to show the peptides share a propensity to self-associate into organized polymeric structures mediated predominantly by hydrophobic interactions between the olefinic chain and the aromatic side-chains from the peptide. We have also investigated in detail the structural significance of the length and position of the staple, and of olefinic bond isomerization in stabilizing the helical conformation of the peptides as potential factors driving polymerization. This study presents the numerous challenges of designing biologically active stapled peptides and the conclusions have broad implications for optimizing a promising new class of compounds in drug discovery. PMID:22170623

Implementation of a sliding-mode-based position sensorless drive for high-speed micro permanent-magnet synchronous motors.

PubMed

Chi, Wen-Chun; Cheng, Ming-Yang

2014-03-01

Due to issues such as limited space, it is difficult if it is not impossible to employ a position sensor in the drive control of high-speed micro PMSMs. In order to alleviate this problem, this paper analyzes and implements a simple and robust position sensorless field-oriented control method of high-speed micro PMSMs based on the sliding-mode observer. In particular, the angular position and velocity of the rotor of the high-speed micro PMSM are estimated using the sliding-mode observer. This observer is able to accurately estimate rotor position in the low speed region and guarantee fast convergence of the observer in the high speed region. The proposed position sensorless control method is suitable for electric dental handpiece motor drives where a wide speed range operation is essential. The proposed sensorless FOC method is implemented using a cost-effective 16-bit microcontroller and tested in a prototype electric dental handpiece motor. Several experiments are performed to verify the effectiveness of the proposed method. © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

Effects of frequency- and direction-dependent elastic materials on linearly elastic MRE image reconstructions

NASA Astrophysics Data System (ADS)

Perreard, I. M.; Pattison, A. J.; Doyley, M.; McGarry, M. D. J.; Barani, Z.; Van Houten, E. E.; Weaver, J. B.; Paulsen, K. D.

2010-11-01

The mechanical model commonly used in magnetic resonance elastography (MRE) is linear elasticity. However, soft tissue may exhibit frequency- and direction-dependent (FDD) shear moduli in response to an induced excitation causing a purely linear elastic model to provide an inaccurate image reconstruction of its mechanical properties. The goal of this study was to characterize the effects of reconstructing FDD data using a linear elastic inversion (LEI) algorithm. Linear and FDD phantoms were manufactured and LEI images were obtained from time-harmonic MRE acquisitions with variations in frequency and driving signal amplitude. LEI responses to artificially imposed uniform phase shifts in the displacement data from both purely linear elastic and FDD phantoms were also evaluated. Of the variety of FDD phantoms considered, LEI appeared to tolerate viscoelastic data-model mismatch better than deviations caused by poroelastic and anisotropic mechanical properties in terms of visual image contrast. However, the estimated shear modulus values were substantially incorrect relative to independent mechanical measurements even in the successful viscoelastic cases and the variations in mean values with changes in experimental conditions associated with uniform phase shifts, driving signal frequency and amplitude were unpredictable. Overall, use of LEI to reconstruct data acquired in phantoms with FDD material properties provided biased results under the best conditions and significant artifacts in the worst cases. These findings suggest that the success with which LEI is applied to MRE data in tissue will depend on the underlying mechanical characteristics of the tissues and/or organs systems of clinical interest.

Effects of frequency- and direction-dependent elastic materials on linearly elastic MRE image reconstructions.

PubMed

Perreard, I M; Pattison, A J; Doyley, M; McGarry, M D J; Barani, Z; Van Houten, E E; Weaver, J B; Paulsen, K D

2010-11-21

The mechanical model commonly used in magnetic resonance elastography (MRE) is linear elasticity. However, soft tissue may exhibit frequency- and direction-dependent (FDD) shear moduli in response to an induced excitation causing a purely linear elastic model to provide an inaccurate image reconstruction of its mechanical properties. The goal of this study was to characterize the effects of reconstructing FDD data using a linear elastic inversion (LEI) algorithm. Linear and FDD phantoms were manufactured and LEI images were obtained from time-harmonic MRE acquisitions with variations in frequency and driving signal amplitude. LEI responses to artificially imposed uniform phase shifts in the displacement data from both purely linear elastic and FDD phantoms were also evaluated. Of the variety of FDD phantoms considered, LEI appeared to tolerate viscoelastic data-model mismatch better than deviations caused by poroelastic and anisotropic mechanical properties in terms of visual image contrast. However, the estimated shear modulus values were substantially incorrect relative to independent mechanical measurements even in the successful viscoelastic cases and the variations in mean values with changes in experimental conditions associated with uniform phase shifts, driving signal frequency and amplitude were unpredictable. Overall, use of LEI to reconstruct data acquired in phantoms with FDD material properties provided biased results under the best conditions and significant artifacts in the worst cases. These findings suggest that the success with which LEI is applied to MRE data in tissue will depend on the underlying mechanical characteristics of the tissues and/or organs systems of clinical interest.

Fast-acting nuclear reactor control device

DOEpatents

Kotlyar, Oleg M.; West, Phillip B.

1993-01-01

A fast-acting nuclear reactor control device for moving and positioning a fety control rod to desired positions within the core of the reactor between a run position in which the safety control rod is outside the reactor core, and a shutdown position in which the rod is fully inserted in the reactor core. The device employs a hydraulic pump/motor, an electric gear motor, and solenoid valve to drive the safety control rod into the reactor core through the entire stroke of the safety control rod. An overrunning clutch allows the safety control rod to freely travel toward a safe position in the event of a partial drive system failure.

Hysteresis Bearingless Slice Motors with Homopolar Flux-biasing.

PubMed

Noh, Minkyun; Gruber, Wolfgang; Trumper, David L

2017-10-01

We present a new concept of bearingless slice motor that levitates and rotates a ring-shaped solid rotor. The rotor is made of a semi-hard magnetic material exhibiting magnetic hysteresis, such as D2 steel. The rotor is radially biased with a homopolar permanent-magnetic flux, on which the stator can superimpose 2-pole flux to generate suspension forces. By regulating the suspension forces based on position feedback, the two radial rotor degrees of freedom are actively stabilized. The two tilting degrees of freedom and the axial translation are passively stable due to the reluctance forces from the bias flux. In addition, the stator can generate a torque by superimposing 6- pole rotating flux, which drags the rotor via hysteresis coupling. This 6-pole flux does not generate radial forces in conjunction with the homopolar flux or 2-pole flux, and therefore the suspension force generation is in principle decoupled from the driving torque generation. We have developed a prototype system as a proof of concept. The stator has twelve teeth, each of which has a single phase winding that is individually driven by a linear transconductance power amplifier. The system has four reflective-type optical sensors to differentially measure the two radial degrees of freedom of the rotor. The suspension control loop is implemented such that the phase margin is 25 degrees at the cross-over frequency of 110 Hz. The prototype system can levitate the rotor and drive it up to about 1730 rpm. The maximum driving torque is about 2.7 mNm.

Quantifying the Arousal Threshold Using Polysomnography in Obstructive Sleep Apnea.

PubMed

Sands, Scott A; Terrill, Philip I; Edwards, Bradley A; Taranto Montemurro, Luigi; Azarbarzin, Ali; Marques, Melania; de Melo, Camila M; Loring, Stephen H; Butler, James P; White, David P; Wellman, Andrew

2018-01-01

Precision medicine for obstructive sleep apnea (OSA) requires noninvasive estimates of each patient's pathophysiological "traits." Here, we provide the first automated technique to quantify the respiratory arousal threshold-defined as the level of ventilatory drive triggering arousal from sleep-using diagnostic polysomnographic signals in patients with OSA. Ventilatory drive preceding clinically scored arousals was estimated from polysomnographic studies by fitting a respiratory control model (Terrill et al.) to the pattern of ventilation during spontaneous respiratory events. Conceptually, the magnitude of the airflow signal immediately after arousal onset reveals information on the underlying ventilatory drive that triggered the arousal. Polysomnographic arousal threshold measures were compared with gold standard values taken from esophageal pressure and intraoesophageal diaphragm electromyography recorded simultaneously (N = 29). Comparisons were also made to arousal threshold measures using continuous positive airway pressure (CPAP) dial-downs (N = 28). The validity of using (linearized) nasal pressure rather than pneumotachograph ventilation was also assessed (N = 11). Polysomnographic arousal threshold values were correlated with those measured using esophageal pressure and diaphragm EMG (R = 0.79, p < .0001; R = 0.73, p = .0001), as well as CPAP manipulation (R = 0.73, p < .0001). Arousal threshold estimates were similar using nasal pressure and pneumotachograph ventilation (R = 0.96, p < .0001). The arousal threshold in patients with OSA can be estimated using polysomnographic signals and may enable more personalized therapeutic interventions for patients with a low arousal threshold. © Sleep Research Society 2017. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

Batu Pahat Driving Cycle for Light Duty Gasoline Engine

NASA Astrophysics Data System (ADS)

Zainul Abidin, Zainul Ameerul Ikhsan B.; Faisal Hushim, Mohd; Ahmad, Osman Bin

2017-08-01

Driving cycle is a series of data points that represents the vehicle speed versus time. Transient driving cycles involve many changes such as frequent speed changes during typical on-road driving condition [2]. Model driving cycles involve protracted periods at constant speeds. The Batu Pahat Driving Cycle (BPDC) developed to represent the driving pattern of people in a district of Batu Pahat. Based on this driving cycle, it will be a reference to other researchers to study about the gases emission release and fuel consumption by the vehicle on the dynamometer or automotive simulation based on this driving cycle. Existing driving cycles used such as the New European Driving Cycle (NEDC), the Federal Test Procedure (FTP-72/75, and Japan 10-15 Mode Cycle is not appropriate for Batu Pahat district because of different road conditions, driving habits and environmental of developed driving cycle countries are not same [2][14]. Batu Pahat drive cycle was developed for low-capacity gasoline engine under 150 cc and operating on urban roads, rural roads and road around Universiti Tun Hussein Onn. The importance of these driving cycle as the reference for other research to measure and do automotive simulation regarding fuel consumption and gas emission release from the motorcycle for these three type of driving cycle area. Another use for driving cycles is in vehicle simulations [3]. More specifically, they are used in propulsion system simulations to predict the performance of internal combustion engines, transmissions, electric drive systems, batteries, fuel cell systems, and similar components [18]. Data collection methods used in this study is the use of Global Positioning System (GPS). The results obtained are not similar to each other due to differences in congestion on data taken. From the driving cycle graph obtained, such as the average velocity, maximum velocity, the duration and Positive Acceleration Kinetic Energy (PKE) can be determined. In addition, the best driving cycle sample can be determined from the sum of error calculated. The least sum of error means the best driving cycle

Experimental research of flow servo-valve

NASA Astrophysics Data System (ADS)

Takosoglu, Jakub

Positional control of pneumatic drives is particularly important in pneumatic systems. Some methods of positioning pneumatic cylinders for changeover and tracking control are known. Choking method is the most development-oriented and has the greatest potential. An optimal and effective method, particularly when applied to pneumatic drives, has been searched for a long time. Sophisticated control systems with algorithms utilizing artificial intelligence methods are designed therefor. In order to design the control algorithm, knowledge about real parameters of servo-valves used in control systems of electro-pneumatic servo-drives is required. The paper presents the experimental research of flow servo-valve.

Psychological predictors of college students' cell phone use while driving.

PubMed

Schlehofer, Michèle M; Thompson, Suzanne C; Ting, Sarah; Ostermann, Sharon; Nierman, Angela; Skenderian, Jessica

2010-07-01

Despite the known risk, many people talk on a phone while driving. This study explored psychological predictors of cell phone use while driving. College students (final N=69) completed a survey and predicted their driving performance both with and without a simultaneous phone conversation. Their actual performance on a driving simulator was then assessed. Cell phone use reduced performance on the simulation task. Further, perceiving oneself as good at compensating for driving distractions, overestimating one's performance on the driving simulator, and high illusory control predicted more frequent cell phone use while driving in everyday life. Finally, those who talked more frequently on a phone while driving had poorer real-world driving records. These findings suggest illusory control and positive illusions partly explain driver's decisions of whether to use cell phones while driving. Copyright 2010 Elsevier Ltd. All rights reserved.

VIEW OF DINING ROOM WITH SLIDING DOORS IN CLOSED POSITION. ...

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

VIEW OF DINING ROOM WITH SLIDING DOORS IN CLOSED POSITION. WINDOWS ON THE LEFT HAND SIDE HAVE VIEWS INTO THE CARPORT. VIEW FACING NORTH - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Three-Bedroom Single-Family Type 9, Birch Circle, Elm Drive, Elm Circle, and Date Drive, Pearl City, Honolulu County, HI

Effects of alprazolam on driving ability, memory functioning and psychomotor performance: a randomized, placebo-controlled study.

PubMed

Verster, Joris C; Volkerts, Edmund R; Verbaten, Marinus N

2002-08-01

Alprazolam is prescribed for the treatment of anxiety and panic disorder. Most users are presumably involved in daily activities such as driving. However, the effects of alprazolam on driving ability have never been investigated. This study was conducted to determine the effects of alprazolam (1 mg) on driving ability, memory and psychomotor performance. Twenty healthy volunteers participated in a randomized, double-blind, placebo-controlled crossover study. One hour after oral administration, subjects performed a standardized driving test on a primary highway during normal traffic. They were instructed to drive with a constant speed (90 km/h) while maintaining a steady lateral position within the right traffic lane. Primary performance measures were the Standard Deviation of Lateral Position (SDLP) and the Standard Deviation of Speed (SDS). After the driving test, subjective driving quality, mental effort, and mental activation during driving were assessed. A laboratory test battery was performed 2.5 h after treatment administration, comprising the Sternberg Memory Scanning Test, a Continuous Tracking Test, and a Divided Attention Test. Relative to placebo, alprazolam caused serious driving impairment, as expressed by a significantly increased SDLP (F(1,19) = 97.3, p <.0001) and SDS (F(1,19) = 30.4, p <.0001). This was confirmed by subjective assessments showing significantly impaired driving quality (F(1,19) = 16.4, p <.001), decreased alertness (F(1,19) = 43.4, p <.0001), decreased mental activation (F(1,19) = 5.7, p <.03) and increased mental effort during driving (F(1,19) = 26.4, p <.0001). Furthermore, alprazolam significantly impaired performance on the laboratory tests. In conclusion, alprazolam users must be warned not to drive an automobile or operate potentially dangerous machinery.

Drowsiness detection using heart rate variability.

PubMed

Vicente, José; Laguna, Pablo; Bartra, Ariadna; Bailón, Raquel

2016-06-01

It is estimated that 10-30 % of road fatalities are related to drowsy driving. Driver's drowsiness detection based on biological and vehicle signals is being studied in preventive car safety. Autonomous nervous system activity, which can be measured noninvasively from the heart rate variability (HRV) signal obtained from surface electrocardiogram, presents alterations during stress, extreme fatigue and drowsiness episodes. We hypothesized that these alterations manifest on HRV and thus could be used to detect driver's drowsiness. We analyzed three driving databases in which drivers presented different sleep-deprivation levels, and in which each driving minute was annotated as drowsy or awake. We developed two different drowsiness detectors based on HRV. While the drowsiness episodes detector assessed each minute of driving as "awake" or "drowsy" with seven HRV derived features (positive predictive value 0.96, sensitivity 0.59, specificity 0.98 on 3475 min of driving), the sleep-deprivation detector discerned if a driver was suitable for driving or not, at driving onset, as function of his sleep-deprivation state. Sleep-deprivation state was estimated from the first three minutes of driving using only one HRV feature (positive predictive value 0.80, sensitivity 0.62, specificity 0.88 on 30 drivers). Incorporating drowsiness assessment based on HRV signal may add significant improvements to existing car safety systems.

Diabetes, driving and fasting during Ramadan: the interplay between secular and religious law

PubMed Central

Hussain, Sufyan; Mohammed, Ruzwan; Beshyah, Salem Arifi; Chowdhury, Tahseen A; Sattar, Naveed; Sheikh, Aziz

2018-01-01

A large proportion of the Muslim population fasts during Ramadan. The risk of hypoglycemia is increased with fasting during Ramadan in people with diabetes who are on insulin and insulin secretagogues. Therefore, the combination of fasting with diabetes and driving presents a challenging situation, with legal implications for such individuals and their healthcare professionals. This novel, narrative, non-systematic review discusses the importance of addressing hypoglycemia in fasting with reference to secular legal guidance on driving with diabetes. We discuss religious aspects relating to fasting and driving in Islam. While there is no clear guidance or legal position on diabetes and driving for individuals who are fasting, Islamic law provides a logical framework to address this. Healthcare professionals need to raise and facilitate discussions on this often-overlooked topic with people with diabetes who are planning on fasting to minimize the potential for public harm. For some individuals fasting perhaps should be avoided when driving and that this religiously compatible position would best be adopted when one is dependent on driving for livelihood. Ultimately further research on glycemic control and management when fasting and driving, as well as a formal legal guidance on this topic, is required to safeguard healthcare professionals and the public from the potential dangers of driving with diabetes and fasting. PMID:29892339

Air Liquide's pulse tube cryocooler systems for space applications

NASA Astrophysics Data System (ADS)

Trollier, T.; Tanchon, J.; Rey, J. C.; Ravex, A.; Buquet, J.

2009-05-01

Thanks to important development efforts completed internally and with the European Space Agency (ESA) funding, Air Liquide Advanced Technology Division (AL/DTA) is now in position to propose two Pulse Tube cooler systems in the 40-80K temperature range for coming Earth Observation missions such as Meteosat Third Generation (MTG), SIFTI, etc... The Miniature Pulse Tube Cooler (MPTC) is lifting up to 2.47W@80K with 50W maximal compressor input power and 10°C rejection temperature. The weight is 2.8 kg. The Large Pulse Tube Cooler (LPTC) is providing 2.3W@50K for 160W input power and 10°C rejection temperature. This product is weighing 5.1 kg. The two pulse tube coolers thermo-mechanical units are qualified against environmental constraints as per ESA ECSS-E-30. They are both using dual opposed pistons flexure bearing compressor with moving magnet linear motors in order to ensure very high lifetime. The associated Cooler Drive Electronics is also an important aspect specifically regarding the active control of the cooler thermo-mechanical unit during the launch phase and the active reduction of the vibrations induced by the compressor (partly supported by the French Agency CNES). This paper details the presentation of the two Pulse Tube Coolers together with the Cooler Drive Electronics aspects.

Photonically driven DNA nanomachine with hybrid functions towards cell measurement

NASA Astrophysics Data System (ADS)

Ogura, Yusuke; Nishimura, Takahiro; Yamada, Kenji; Tanida, Jun

2018-02-01

Physical properties of a cell are often valuable information about the status of the cell, and developing technologies to measure such properties is important to enhance the progress in, for example, diagnosis of diseases. In this paper, we present a photonically driven DNA nanomachine with hybrid functions: providing a physical operation to a cell and reporting the cell's response. The DNA nanomachine can be controlled according to optical signals, and therefore the measurement is achieved locally at designated positions and at desired times. Black hole quenchers (BHQs) are introduced to drive the DNA nanomachine using light. When the DNA nanomachine is irradiated with the light at the excitation wavelength of the BHQs, the thermal energy is produced from the BHQs to drive the DNA nanomachine. To demonstrate a basic functionality, we constructed a DNA nanomachine that transformed between a linear conformation and a hairpin-like conformation depending on the presence or absence of a controlling DNA. This conformation change will be able to provide a force to deform cells as a physical operation. The response of the cell is reported as fluorescence resonance energy transfer (FRET) signals. An experimental result demonstrated that the FRET signal changed according to the presence or absence of the controlling DNA. The method is expected to be useful in measuring the stiffness of a cell.

Air liquide's space pulse tube cryocooler systems

NASA Astrophysics Data System (ADS)

Trollier, T.; Tanchon, J.; Buquet, J.; Ravex, A.

2017-11-01

Thanks to important development efforts completed with ESA funding, Air Liquide Advanced Technology Division (AL/DTA), is now in position to propose two Pulse Tube cooler systems in the 40-80K temperature range for coming Earth Observation missions such as Meteosat Third Generation (MTG), SIFTI, etc… The Miniature Pulse Tube Cooler (MPTC) is lifting up to 2.47W@80K with 50W compressor input power and 10°C rejection temperature. The weight is 2.8 kg. The Large Pulse Tube Cooler (LPTC) is providing 2.3W@50K for 160W input power and 10°C rejection temperature. This product is weighing 5.1 kg. The two pulse tube coolers thermo-mechanical units are qualified against environmental constraints as per ECSS-E-30. They are both using dual opposed pistons flexure bearing compressor with moving magnet linear motors in order to ensure very high lifetime. The associated Cooler Drive Electronics is also an important aspect specifically regarding the active control of the cooler thermo-mechanical unit during the launch phase and the active reduction of the vibrations induced by the compressor (partly supported by the French Agency CNES). This paper details the presentation of the two Pulse Tube Coolers together with the Cooler Drive Electronics aspects.

Vibration suppression of advanced space cryocoolers - an overview

NASA Technical Reports Server (NTRS)

Ross, R. G., Jr.

2003-01-01

This paper provides an overview of the vibration characteristics of typical linear-drive space cryocoolers, outlines the history of development and typical performance of the various active and passive vibration suppression systems being used.

The Effects of Low Dose-Rate Ionizing Radiation on the Shapes of Transients in the LM124 Operational Amplifier

NASA Technical Reports Server (NTRS)

Buchner, Stephen; McMorrow, Dale; Roche, Nicholas; Dusseau, Laurent; Pease, Ron L.

2008-01-01

Shapes of single event transients (SETs) in a linear bipolar circuit (LM124) change with exposure to total ionizing dose (TID) radiation. SETs shape changes are a direct consequence of TID-induced degradation of bipolar transistor gain. A reduction in transistor gain causes a reduction in the drive current of the current sources in the circuit, and it is the lower drive current that most affects the shapes of large amplitude SETs.

Linear hydraulic drive system for a Stirling engine

DOEpatents

Walsh, Michael M.

1984-02-21

A hydraulic drive system operating from the periodic pressure wave produced by a Stirling engine along a first axis thereof and effecting transfer of power from the Stirling engine to a load apparatus therefor and wherein the movable, or working member of the load apparatus is reciprocatingly driven along an axis substantially at right angles to the first axis to achieve an arrangement of a Stirling engine and load apparatus assembly which is much shorter and the components of the load apparatus more readily accessible.

Vehicle dynamics control of four in-wheel motor drive electric vehicle using gain scheduling based on tyre cornering stiffness estimation

NASA Astrophysics Data System (ADS)

Xiong, Lu; Yu, Zhuoping; Wang, Yang; Yang, Chen; Meng, Yufeng

2012-06-01

This paper focuses on the vehicle dynamic control system for a four in-wheel motor drive electric vehicle, aiming at improving vehicle stability under critical driving conditions. The vehicle dynamics controller is composed of three modules, i.e. motion following control, control allocation and vehicle state estimation. Considering the strong nonlinearity of the tyres under critical driving conditions, the yaw motion of the vehicle is regulated by gain scheduling control based on the linear quadratic regulator theory. The feed-forward and feedback gains of the controller are updated in real-time by online estimation of the tyre cornering stiffness, so as to ensure the control robustness against environmental disturbances as well as parameter uncertainty. The control allocation module allocates the calculated generalised force requirements to each in-wheel motor based on quadratic programming theory while taking the tyre longitudinal/lateral force coupling characteristic into consideration. Simulations under a variety of driving conditions are carried out to verify the control algorithm. Simulation results indicate that the proposed vehicle stability controller can effectively stabilise the vehicle motion under critical driving conditions.

Safe Driving Climate among Friends (SDCaF): A new scale.

PubMed

Guggenheim, Noga; Taubman-Ben-Ari, Orit

2018-01-01

Reckless driving among young people, especially young men, is a major cause of injury and fatalities the world over. Like other aspects of this age group, young drivers' driving behaviors and norms are influenced by the accepted social discourse of their peers. Yet despite extensive existing knowledge on young drivers, very few studies have dealt specifically with their characteristic friendship relations. This lacuna in the literature may reflect the absence of specific research tools for examining driving with friends. To fill this gap, we conducted a series of studies with 706 young drivers (aged 17-24) of both sexes aimed at developing and validating a multidimensional scale designed to examine the effect of the social relations of adolescents and young adults on their driving. Entitled Safe Driving Climate among Friends (SDCaF), the final scale consists of 19 items, which tap four dimensions of driving with friends: friends' pressure; social costs of driving with friends; communication with friends about driving; and shared commitment to safe driving. The validity of the scale was established by examining associations between its four dimensions and various variables of personality, friendship, and driving. The findings indicate good reliability and validity, with the three variables of resistance to peer influence, self-disclosure, and personal responsibility for safe driving yielding positive associations with the SDCaF dimensions communication and shared commitment to safe driving, and negative associations with the dimensions friends' pressure and social costs. General tendency to respond to social pressure was positively associated with the dimensions of friends' pressure and social costs, and negatively associated with shared commitment to safe driving. Gender differences were also found, with men scoring higher than women on friends' pressure, and lower than women on shared commitment to safe driving. The SDCaF can serve as a research tool, as well as a diagnostic instrument for detecting susceptibility to reckless driving among young drivers, thereby aiding in the design of targeted educational and intervention programs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Driving with homonymous visual field loss: a review of the literature

PubMed Central

Bowers, Alex R.

2016-01-01

Driving is an important rehabilitation goal for patients with homonymous field defects (HFDs); however, whether or not people with HFDs should be permitted to drive is not clear. Over the last 15 years there has been a marked increase in the number of studies evaluating the effects of HFDs on driving performance. This review of the literature provides a much-needed summary for practitioners and researchers, addressing the following topics: regulations pertaining to driving with HFDs, self-reported driving difficulties, pass rates in on-road tests, the effects of HFDs on lane position and steering stability, the effects of HFDs on scanning and detection of potential hazards, screening for potential fitness to drive, evaluating practical fitness to drive, and the efficacy of interventions to improve driving of persons with HFDs. Although there is clear evidence from on-road studies that some people with HFDs may be rated as safe to drive, others are reported to have significant deficits in skills important for safe driving including taking a lane position too close to one side of the travel lane, unstable steering and inadequate viewing (scanning) behaviors. Driving simulator studies have provided strong evidence of a wide range in compensatory scanning abilities and detection performance, despite similar amounts of visual field loss. Conventional measurements of visual field extent (in which eye movements are not permitted) do not measure such compensatory abilities and are not predictive of on-road driving performance; thus, there is a need to develop better tests to screen for visual fitness to drive of people with HFDs. We are not yet at a point where we can predict which HFD patient is likely to be a safe driver. Therefore, it seems only fair to provide an opportunity for individualized assessments of practical fitness to drive either on the road and/or in a driving simulator. PMID:27535208

Driving with homonymous visual field loss: a review of the literature.

PubMed

Bowers, Alex R

2016-09-01

Driving is an important rehabilitation goal for patients with homonymous field defects (HFDs); however, whether or not people with HFDs should be permitted to drive is not clear. Over the last 15 years, there has been a marked increase in the number of studies evaluating the effects of HFDs on driving performance. This review of the literature provides a much-needed summary for practitioners and researchers, addressing the following topics: regulations pertaining to driving with HFDs, self-reported driving difficulties, pass rates in on-road tests, the effects of HFDs on lane position and steering stability, the effects of HFDs on scanning and detection of potential hazards, screening for potential fitness to drive, evaluating practical fitness to drive and the efficacy of interventions to improve driving of persons with HFDs. Although there is clear evidence from on-road studies that some people with HFDs may be rated as safe to drive, others are reported to have significant deficits in skills important for safe driving, including taking a lane position too close to one side of the travel lane, unstable steering and inadequate viewing (scanning) behaviour. Driving simulator studies have provided strong evidence of a wide range in compensatory scanning abilities and detection performance, despite similar amounts of visual field loss. Conventional measurements of visual field extent (in which eye movements are not permitted) do not measure such compensatory abilities and are not predictive of on-road driving performance. Thus, there is a need to develop better tests to screen people with HFDs for visual fitness to drive. We are not yet at a point where we can predict which HFD patient is likely to be a safe driver. Therefore, it seems only fair to provide an opportunity for individualised assessments of practical fitness to drive either on the road and/or in a driving simulator. © 2016 Optometry Australia.

Drinking and Driving in the United States: Comparing Results from the 2007 and 1996 National Roadside Surveys

PubMed Central

Kelley-Baker, Tara; Lacey, John H.; Voas, Robert B.; Romano, Eduardo; Yao, Jie; Berning, Amy

2013-01-01

Objectives The objectives of this study were to (a) use data from the 2007 National Roadside Survey (NRS) to determine the characteristics of weekend nighttime drivers with positive blood alcohol concentrations (BACs) on U.S. roads in 2007; (b) determine the relationship of the driving environment and trip characteristics associated with drinking drivers; and (c) compare the findings for the 2007 NRS with those for the 1996 NRS. Methods Like the 1996 NRS, the 2007 NRS used a stratified random national roadside survey sample of the contiguous 48 states and collected nighttime data on Fridays and Saturdays between 10 PM and 3 AM. Officers directed 8,384 drivers into off-road parking areas where our research team asked them to participate in the survey. Results Of those approached, 7,159 (85.4%) provided a breath test. Results revealed that 12% of the nighttime drivers had positive BACs, and of those, 2% were higher than the .08 BAC illegal limit in the United States. Since the 1996 NRS, we found significant reductions in the percentage of BAC-positive drivers across different demographic groups. Age was among the most significant factors associated with a weekend driver having a positive BAC. The probability that a driver would be drinking peaked in the 21- to 25-year-old age group. Male drivers were more likely than female drivers to be drinking, and Asian and Hispanic drivers were less likely than White drivers to be drinking. Drinking drivers were more likely to be driving short distances (5 or fewer miles), late at night (between 1 and 3 AM), and to be coming from a bar or restaurant. Finally, 26% of the drivers who reported that they would drive less than 5 miles on the night of the survey had positive BACs, compared to only 16% who indicated they would drive between 6 and 20 miles and 10% who planned to drive more than 20 miles. Conclusions The 2007 NRS provides another benchmark in the four-decade record of drinking drivers on American roads and provides a basis for measuring progress in combating driving under the influence during the coming decade. PMID:23343019

Fault tolerant operation of switched reluctance machine

NASA Astrophysics Data System (ADS)

Wang, Wei

The energy crisis and environmental challenges have driven industry towards more energy efficient solutions. With nearly 60% of electricity consumed by various electric machines in industry sector, advancement in the efficiency of the electric drive system is of vital importance. Adjustable speed drive system (ASDS) provides excellent speed regulation and dynamic performance as well as dramatically improved system efficiency compared with conventional motors without electronics drives. Industry has witnessed tremendous grow in ASDS applications not only as a driving force but also as an electric auxiliary system for replacing bulky and low efficiency auxiliary hydraulic and mechanical systems. With the vast penetration of ASDS, its fault tolerant operation capability is more widely recognized as an important feature of drive performance especially for aerospace, automotive applications and other industrial drive applications demanding high reliability. The Switched Reluctance Machine (SRM), a low cost, highly reliable electric machine with fault tolerant operation capability, has drawn substantial attention in the past three decades. Nevertheless, SRM is not free of fault. Certain faults such as converter faults, sensor faults, winding shorts, eccentricity and position sensor faults are commonly shared among all ASDS. In this dissertation, a thorough understanding of various faults and their influence on transient and steady state performance of SRM is developed via simulation and experimental study, providing necessary knowledge for fault detection and post fault management. Lumped parameter models are established for fast real time simulation and drive control. Based on the behavior of the faults, a fault detection scheme is developed for the purpose of fast and reliable fault diagnosis. In order to improve the SRM power and torque capacity under faults, the maximum torque per ampere excitation are conceptualized and validated through theoretical analysis and experiments. With the proposed optimal waveform, torque production is greatly improved under the same Root Mean Square (RMS) current constraint. Additionally, position sensorless operation methods under phase faults are investigated to account for the combination of physical position sensor and phase winding faults. A comprehensive solution for position sensorless operation under single and multiple phases fault are proposed and validated through experiments. Continuous position sensorless operation with seamless transition between various numbers of phase fault is achieved.

Employment of CB models for non-linear dynamic analysis

NASA Technical Reports Server (NTRS)

Klein, M. R. M.; Deloo, P.; Fournier-Sicre, A.

1990-01-01

The non-linear dynamic analysis of large structures is always very time, effort and CPU consuming. Whenever possible the reduction of the size of the mathematical model involved is of main importance to speed up the computational procedures. Such reduction can be performed for the part of the structure which perform linearly. Most of the time, the classical Guyan reduction process is used. For non-linear dynamic process where the non-linearity is present at interfaces between different structures, Craig-Bampton models can provide a very rich information, and allow easy selection of the relevant modes with respect to the phenomenon driving the non-linearity. The paper presents the employment of Craig-Bampton models combined with Newmark direct integration for solving non-linear friction problems appearing at the interface between the Hubble Space Telescope and its solar arrays during in-orbit maneuvers. Theory, implementation in the FEM code ASKA, and practical results are shown.

Optimization of Smart Structure for Improving Servo Performance of Hard Disk Drive

NASA Astrophysics Data System (ADS)

Kajiwara, Itsuro; Takahashi, Masafumi; Arisaka, Toshihiro

Head positioning accuracy of the hard disk drive should be improved to meet today's increasing performance demands. Vibration suppression of the arm in the hard disk drive is very important to enhance the servo bandwidth of the head positioning system. In this study, smart structure technology is introduced into the hard disk drive to suppress the vibration of the head actuator. It has been expected that the smart structure technology will contribute to the development of small and light-weight mechatronics devices with the required performance. First, modeling of the system is conducted with finite element method and modal analysis. Next, the actuator location and the control system are simultaneously optimized using genetic algorithm. Vibration control effect with the proposed vibration control mechanisms has been evaluated by some simulations.

Optimization and Analysis of a U-Shaped Linear Piezoelectric Ultrasonic Motor Using Longitudinal Transducers

PubMed Central

Yu, Hongpeng; Quan, Qiquan; Tian, Xinqi; Li, He

2018-01-01

A novel U-shaped piezoelectric ultrasonic motor that mainly focused on miniaturization and high power density was proposed, fabricated, and tested in this work. The longitudinal vibrations of the transducers were excited to form the elliptical movements on the driving feet. Finite element method (FEM) was used for design and analysis. The resonance frequencies of the selected vibration modes were tuned to be very close to each other with modal analysis and the movement trajectories of the driving feet were gained with transient simulation. The vibration modes and the mechanical output abilities were tested to evaluate the proposed motor further by a prototype. The maximum output speed was tested to be 416 mm/s, the maximum thrust force was 21 N, and the maximum output power was 5.453 W under frequency of 29.52 kHz and voltage of 100 Vrms. The maximum output power density of the prototype reached 7.59 W/kg, which was even greater than a previous similar motor under the exciting voltage of 200 Vrms. The proposed motor showed great potential for linear driving of large thrust force and high power density. PMID:29518963

Optimization and Analysis of a U-Shaped Linear Piezoelectric Ultrasonic Motor Using Longitudinal Transducers.

PubMed

Yu, Hongpeng; Quan, Qiquan; Tian, Xinqi; Li, He

2018-03-07

A novel U-shaped piezoelectric ultrasonic motor that mainly focused on miniaturization and high power density was proposed, fabricated, and tested in this work. The longitudinal vibrations of the transducers were excited to form the elliptical movements on the driving feet. Finite element method (FEM) was used for design and analysis. The resonance frequencies of the selected vibration modes were tuned to be very close to each other with modal analysis and the movement trajectories of the driving feet were gained with transient simulation. The vibration modes and the mechanical output abilities were tested to evaluate the proposed motor further by a prototype. The maximum output speed was tested to be 416 mm/s, the maximum thrust force was 21 N, and the maximum output power was 5.453 W under frequency of 29.52 kHz and voltage of 100 V rms . The maximum output power density of the prototype reached 7.59 W/kg, which was even greater than a previous similar motor under the exciting voltage of 200 V rms . The proposed motor showed great potential for linear driving of large thrust force and high power density.

Design and model for the giant magnetostrictive actuator used on an electronic controlled injector

NASA Astrophysics Data System (ADS)

Xue, Guangming; Zhang, Peilin; He, Zhongbo; Li, Ben; Rong, Ce

2017-05-01

Giant magnetostrictive actuator (GMA) may be a promising candidate actuator to drive an electronic controlled injector as giant magnetostrictive material (GMM) has excellent performances as large output, fast response and high operating stability etc. To meet the driving requirement of the injector, the GMA should produce maximal shortening displacement when energized. An unbiased GMA with a ‘T’ shaped output rod is designed to reach the target. Furthermore, an open-hold-fall type driving voltage is exerted on the actuator coil to accelerate the response speed of the coil current. The actuator displacement is modeled from establishing the sub-models of coil current, magnetic field within GMM rod, magnetization and magnetostrictive strain sequentially. Two modifications are done to make the model more accurate. Firstly, consider the model fails to compute the transient-state response precisely, a dead-zone and delay links are embedded into the coil current sub-model. Secondly, as the magnetization and magnetostrictive strain sub-models just influence the change rule of the transient-state response the linear magnetostrictive strain-magnetic field sub-model is introduced. From experimental results, the modified model with linear magnetostrictive stain expression can predict the actuator displacement quite effectively.

14 CFR 27.923 - Rotor drive system and control mechanism tests.

Code of Federal Regulations, 2010 CFR

2010-01-01

... the position that will give maximum longitudinal cyclic pitch change to simulate forward flight. The... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Rotor drive system and control mechanism....923 Rotor drive system and control mechanism tests. (a) Each part tested as prescribed in this section...

Analytical Studies on the Synchronization of a Network of Linearly-Coupled Simple Chaotic Systems

NASA Astrophysics Data System (ADS)

Sivaganesh, G.; Arulgnanam, A.; Seethalakshmi, A. N.; Selvaraj, S.

2018-05-01

We present explicit generalized analytical solutions for a network of linearly-coupled simple chaotic systems. Analytical solutions are obtained for the normalized state equations of a network of linearly-coupled systems driven by a common chaotic drive system. Two parameter bifurcation diagrams revealing the various hidden synchronization regions, such as complete, phase and phase-lag synchronization are identified using the analytical results. The synchronization dynamics and their stability are studied using phase portraits and the master stability function, respectively. Further, experimental results for linearly-coupled simple chaotic systems are presented to confirm the analytical results. The synchronization dynamics of a network of chaotic systems studied analytically is reported for the first time.

Variable-pulse-shape pulsed-power accelerator

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

Stoltzfus, Brian S.; Austin, Kevin; Hutsel, Brian Thomas

A variable-pulse-shape pulsed-power accelerator is driven by a large number of independent LC drive circuits. Each LC circuit drives one or more coaxial transmission lines that deliver the circuit's output power to several water-insulated radial transmission lines that are connected in parallel at small radius by a water-insulated post-hole convolute. The accelerator can be impedance matched throughout. The coaxial transmission lines are sufficiently long to transit-time isolate the LC drive circuits from the water-insulated transmission lines, which allows each LC drive circuit to be operated without being affected by the other circuits. This enables the creation of any power pulsemore » that can be mathematically described as a time-shifted linear combination of the pulses of the individual LC drive circuits. Therefore, the output power of the convolute can provide a variable pulse shape to a load that can be used for magnetically driven, quasi-isentropic compression experiments and other applications.« less

[Role of some psycho-physiological factors on driving safety].

PubMed

Bergomi, M; Vivoli, G; Rovesti, S; Bussetti, P; Ferrari, A; Vivoli, R

2010-01-01

Within a research project on the role played by human factors on road accidents, the aim of the present study is to evaluate, in young adults, the relationships between driver behaviour and personality factors as well as to assess the neuroendocrine correlates of psychological and behavioural factors investigated. Another aim is to estimate in what measure the performance levels are affected by demographic, psychological and chronobiological variables. It has been found a positive relation between highway code violations, extroversion trait of personality and Sensation Seeking scores, so confirming that this component of personality can affect risky behaviour. Furthermore the subjects more oriented to morningness chronotype were found to be prone to adopt safe driving behaviour. Regarding the relations of the neuroendocrine parameters and driving behaviour a positive correlation was observed between dopamine levels and frequency of driving violations while a negative relationship was found between adrenaline levels and frequency of driving errors. In conclusion the identification of psycho-physiological variables related to driving risky behaviour might be a useful instrument to design traffic safety programs tailored to high risk subjects.

Road characteristics and driver fatigue: a simulator study.

PubMed

Oron-Gilad, Tal; Ronen, Adi

2007-09-01

Two experiments examined the influence of road characteristics on driver fatigue in a prolonged simulator drive. In experiment one, ten military truck drivers drove a mixed route, with straight, winding, and straight highway segments. In experiment two, 16 additional drivers drove either a straight, a winding, or a mixed route. Fatigue symptoms were assessed using performance, subjective, and psychophysiological measures (HRV). We hypothesized that drivers adopt different fatigue-coping strategies relative to the demands of the drive. Thus, on straight roads drivers are more likely to loosen their driving demands by either increasing their driving speed and/or not maintaining the lane position, as the road is tolerant to both strategies, whereas on winding roads, drivers are more likely to increase their speed but not their lane positioning. Our results confirm that decremental changes in driving performance varied among road types. In the straight road components, we found decrements in the quality of lane maintaining (experiment one) and steering quality (experiments one and two) and longitudinal speed (experiment two). In the winding road, we found that drivers increased their driving speed over time (experiments one and two).

Drinking and driving in southeastern Brazil: results from a roadside survey study.

PubMed

Campos, Valdir Ribeiro; de Souza E Silva, Rebeca; Duailibi, Sérgio; Laranjeira, Ronaldo; Palacios, Ester Nakamura; Grube, Joel W; Pinsky, Ilana

2013-01-01

The objective of this study is to present data from a roadside survey study on drinking and driving and alcohol consumption in southeastern Brazil. A cross-sectional roadside survey study using a questionnaire and breathalyzer data is the method used to determine the prevalence of drinking and driving and to examine whether socio-demographic characteristics and drivers' behavior, attitude and alcohol consumption predicted positive blood alcohol content (BAC). The data were gathered from 2005 to 2007 through roadside surveys conducted on high volume public roads in four cities in southeastern Brazil. A total of 4182 randomly selected drivers took part in the research. Of these drivers, 3488 (83.4%) completed the questionnaire and agreed to take a breath test. Overall, 24.6% of drivers had a detectable blood alcohol concentration (BAC) and 15.9% had a BAC above the legal limit (0.6g/l) at the time of the study. Logistic regression controlling for locale (city), sex, age and marital status was used to predict whether each driver would present a positive breath test. Socio-demographic characteristics, driving behaviors and attitudes, and alcohol consumption patterns were included as predictors. These analyses indicated that those who believed drinking and driving was a serious offense were about two-thirds as likely to have a positive breath test, and that drivers reporting a pattern of regular alcohol use were three times as likely to have a positive breath test. These findings indicate that drinking and driving is relatively common in Brazil, and that it occurs considerably more frequently than similar surveys suggest, is the case in other countries. Copyright © 2012 Elsevier Ltd. All rights reserved.

The effects of intranasal esketamine (84 mg) and oral mirtazapine (30 mg) on on-road driving performance: a double-blind, placebo-controlled study.

PubMed

van de Loo, Aurora J A E; Bervoets, Adriana C; Mooren, Loes; Bouwmeester, Noor H; Garssen, Johan; Zuiker, Rob; van Amerongen, Guido; van Gerven, Joop; Singh, Jaskaran; der Ark, Peter Van; Fedgchin, Maggie; Morrison, Randall; Wajs, Ewa; Verster, Joris C

2017-11-01

The purpose of this study is to evaluate the single dose effect of intranasal esketamine (84 mg) compared to placebo on on-road driving performance. Mirtazapine (oral, 30 mg) was used as a positive control, as this antidepressant drug is known to negatively affect driving performance. Twenty-six healthy volunteers aged 21 to 60 years were enrolled in this study. In the evening, 8 h after treatment administration, participants conducted the standardized 100-km on-road driving test. Primary outcome measure was the standard deviation of lateral position (SDLP), i.e., the weaving of the car. Mean lateral position, mean speed, and standard deviation of speed were secondary outcome measures. For SDLP, non-inferiority analyses were conducted, using +2.4 cm (relative to placebo) as a predefined non-inferiority margin for clinical relevant impairment. Twenty-four participants completed the study. No significant SDLP difference was found between esketamine and placebo (p = 0.7638), whereas the SDLP after mirtazapine was significantly higher when compared to placebo (p = 0.0001). The upper limit of the two-sided 95% confidence interval (CI) of the mean difference between esketamine and placebo was +0.86 cm, i.e., <+2.4 cm, thus demonstrating that esketamine was non-inferior to placebo. Non-inferiority could not be concluded for mirtazapine (+3.15 cm SDLP relative to placebo). No significant differences in mean speed, standard deviation of speed, and mean lateral position were observed between the active treatments and placebo. No significant difference in driving performance was observed 8 h after administering intranasal esketamine (84 mg) or placebo. In contrast, oral mirtazapine (30 mg) significantly impaired on road driving performance.

Inductive Linear-Position Sensor/Limit-Sensor Units

NASA Technical Reports Server (NTRS)

Alhom, Dean; Howard, David; Smith, Dennis; Dutton, Kenneth

2007-01-01

A new sensor provides an absolute position measurement. A schematic view of a motorized linear-translation stage that contains, at each end, an electronic unit that functions as both (1) a non-contact sensor that measures the absolute position of the stage and (2) a non-contact equivalent of a limit switch that is tripped when the stage reaches the nominal limit position. The need for such an absolute linear position-sensor/limit-sensor unit arises in the case of a linear-translation stage that is part of a larger system in which the actual stopping position of the stage (relative to the nominal limit position) must be known. Because inertia inevitably causes the stage to run somewhat past the nominal limit position, tripping of a standard limit switch or other limit sensor does not provide the required indication of the actual stopping position. This innovative sensor unit operates on an electromagnetic-induction principle similar to that of linear variable differential transformers (LVDTs)

SU-E-T-317: Dynamic Modulated Brachytherapy (DMBT): Robotic Applicator Design.

PubMed

Han, Dae Yup; Webster, Matthew J; Devic, Slobodan; Vuong, Te; Scanderbeg, Dan; Song, William Y

2012-06-01

To investigate the hardware necessary for implementing our Dynamic Modulated Brachytherapy (DMBT) treatment concept for rectal cancer. The DMBT robot has three major parts: 1) shield and shield delivery module, 2) controlling module, and 3) DMBT controlling and monitoring software. The shield is a tungsten alloy cylinder (r=0.95cm, l=4.5cm) with a 5.5mm rectangular-shaped opening. The shield is controlled by an aluminum pipe with gear set (1:3) and linear actuator (2mm/turn). An Ir-192 radiation source will be placed through the aluminum pipe. The power source is a Nema-17 stepping motor with EvoDrive ST-17 (EVA Robotics, Queensland, Australia) and USB-6009 DAQ (National Instrument, Austin, TX). With our in-house operating program through LabView (National Instrument, Austin, TX), we can make and load plans for treatment as well as testing. Checking the shield position is also possible through the operating program. For safety, a lexan sheath tube and emergency buttons are built-in. The DMBT robot has 2 degrees of freedom, which are linear translation and rotation. With our power delivery system, the spatial resolutions are 0.0125mm (linear stage) and 0.012Ëš (rotation). In 0.5s, motors achieve the desired position with the maximum speeds 450 step/s (1Ëš), 7,500 step/s (30Ëš), and 12,000 step/s (5mm). Four registers are triggered with USB-6009 DAQ signals. The operating program includes gages for checking shield position, loading treatment plans, and safety buttons. In all, we have designed the hardware components of the DMBT system for rectal cancer. For treatment, the system needs more elements to support the DMBT robot; lexan sheath tube holder, DMBT robot security joint, and a system for reducing friction between the tube and shield. We will also refine our system to be more compact by using DC servomotors instead of the larger Nema-17 stepping motors. © 2012 American Association of Physicists in Medicine.

Linear quadratic optimization for positive LTI system

NASA Astrophysics Data System (ADS)

Muhafzan, Yenti, Syafrida Wirma; Zulakmal

2017-05-01

Nowaday the linear quadratic optimization subject to positive linear time invariant (LTI) system constitute an interesting study considering it can become a mathematical model of variety of real problem whose variables have to nonnegative and trajectories generated by these variables must be nonnegative. In this paper we propose a method to generate an optimal control of linear quadratic optimization subject to positive linear time invariant (LTI) system. A sufficient condition that guarantee the existence of such optimal control is discussed.

Computer-aided design studies of the homopolar linear synchronous motor

NASA Astrophysics Data System (ADS)

Dawson, G. E.; Eastham, A. R.; Ong, R.

1984-09-01

The linear induction motor (LIM), as an urban transit drive, can provide good grade-climbing capabilities and propulsion/braking performance that is independent of steel wheel-rail adhesion. In view of its 10-12 mm airgap, the LIM is characterized by a low power factor-efficiency product of order 0.4. A synchronous machine offers high efficiency and controllable power factor. An assessment of the linear homopolar configuration of this machine is presented as an alternative to the LIM. Computer-aided design studies using the finite element technique have been conducted to identify a suitable machine design for urban transit propulsion.

Investigation of ODE integrators using interactive graphics. [Ordinary Differential Equations

NASA Technical Reports Server (NTRS)

Brown, R. L.

1978-01-01

Two FORTRAN programs using an interactive graphic terminal to generate accuracy and stability plots for given multistep ordinary differential equation (ODE) integrators are described. The first treats the fixed stepsize linear case with complex variable solutions, and generates plots to show accuracy and error response to step driving function of a numerical solution, as well as the linear stability region. The second generates an analog to the stability region for classes of non-linear ODE's as well as accuracy plots. Both systems can compute method coefficients from a simple specification of the method. Example plots are given.

To bend or not to bend: electronic structural analysis of linear versus bent M-H-M interactions in dinickel bis(dialkylphosphino)methane complexes.

PubMed

Wilson, Zakiya S; Stanley, George G; Vicic, David A

2010-06-21

The M-H-M bonding in the dinuclear complexes Ni(2)(mu-H)(mu-P(2))(2)X(2) (P(2) = R(2)PCH(2)PR(2), R = iPr, Cy; X = Cl, Br) has been investigated. These dinickel A-frames were studied via density functional theory (DFT) calculations to analyze the factors that influence linear and bent M-H-M bonding. The DFT calculations indicate that the bent geometry is favored electronically, with ligand steric effects driving the formation of the linear M-H-M structures.

Occupant Kinematics in Simulated Autonomous Driving Vehicle Collisions: Influence of Seating Position, Direction and Angle.

PubMed

Kitagawa, Yuichi; Hayashi, Shigeki; Yamada, Katsunori; Gotoh, Mitsuaki

2017-11-01

This two-part study analyzed occupant kinematics in simulated collisions of future automated driving vehicles in terms of seating configuration. In part one, a frontal collision was simulated with four occupants with the front seats reversed. The left front seat occupant was unbelted while the others were belted. In part two of the study, occupant restraint was examined in various seating configurations using a single seat model with a three-point seatbelt. The seat direction with respect to impact was considered as forward, rearward, and lateral facing in 45 degree increments. The effect of seat recline was also studied in the forward-facing and rear-facing cases by assuming three positions: driving position, resting position and relaxed position. Occupants were represented by human body finite element models. The results of part one showed that the front seat (rear-facing) occupants were restrained by the seatback, resulting in T1 forward displacement less than 100 mm; the rear seat occupants were restrained by the seatbelt resulting larger T1 forward displacement more than 500 mm. The results of the part two showed the directional dependence of occupant restraint. Greater T1 displacements were observed when the occupant faced lateral or front oblique. However, the seatbelt provided some restraint in all directions considered. The seatback generated contact force to the occupant when it was in the impact direction, including the lateral directions. The relaxed position allowed increased excursion compared to the driving position when the occupant faced rearward, but the magnitude of this increase was lower with lower impact speed.

Monitoring driver fatigue using a single-channel electroencephalographic device: A validation study by gaze-based, driving performance, and subjective data.

PubMed

Morales, José M; Díaz-Piedra, Carolina; Rieiro, Héctor; Roca-González, Joaquín; Romero, Samuel; Catena, Andrés; Fuentes, Luis J; Di Stasi, Leandro L

2017-12-01

Driver fatigue can impair performance as much as alcohol does. It is the most important road safety concern, causing thousands of accidents and fatalities every year. Thanks to technological developments, wearable, single-channel EEG devices are now getting considerable attention as fatigue monitors, as they could help drivers to assess their own levels of fatigue and, therefore, prevent the deterioration of performance. However, the few studies that have used single-channel EEG devices to investigate the physiological effects of driver fatigue have had inconsistent results, and the question of whether we can monitor driver fatigue reliably with these EEG devices remains open. Here, we assessed the validity of a single-channel EEG device (TGAM-based chip) to monitor changes in mental state (from alertness to fatigue). Fifteen drivers performed a 2-h simulated driving task while we recorded, simultaneously, their prefrontal brain activity and saccadic velocity. We used saccadic velocity as the reference index of fatigue. We also collected subjective ratings of alertness and fatigue, as well as driving performance. We found that the power spectra of the delta EEG band showed an inverted U-shaped quadratic trend (EEG power spectra increased for the first hour and half, and decreased during the last thirty minutes), while the power spectra of the beta band linearly increased as the driving session progressed. Coherently, saccadic velocity linearly decreased and speeding time increased, suggesting a clear effect of fatigue. Subjective data corroborated these conclusions. Overall, our results suggest that the TGAM-based chip EEG device is able to detect changes in mental state while performing a complex and dynamic everyday task as driving. Copyright © 2017 Elsevier Ltd. All rights reserved.

Voltage directive drive with claw pole motor and control without rotor position indicator

NASA Astrophysics Data System (ADS)

Stroenisch, Volker Ewald

Design and testing of a voltage directive drive for synchronous variable speed claw pole motor and control without rotor position indicator is described. Economic analysis of the designed regulation is performed. Computations of stationary and dynamic behavior are given and experimental operational behavior is determined. The motors can be used for electric transportation vehicles, diesel motors, and electric railway engines.

LMSS drive simulator for multipath propagation

NASA Technical Reports Server (NTRS)

Vishakantaiah, Praveen; Vogel, Wolfhard J.

1989-01-01

A three-dimensional drive simulator for the prediction of Land Mobile Satellite Service (LMSS) multipath propagation was developed. It is based on simple physical and geometrical rules and can be used to evaluate effects of scatterer numbers and positions, receiving antenna pattern, and satellite frequency and position. It is shown that scatterers close to the receiver have the most effect and that directive antennas suppress multipath interference.

Position and force control of a vehicle with two or more steerable drive wheels

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

Reister, D.B.; Unseren, M.A.

1992-10-01

When a vehicle with two or more steerable drive wheels is traveling in a circle, the motion of the wheels is constrained. The wheel translational velocity divided by the radius to the center of rotation must be the same for all wheels. When the drive wheels are controlled independently using position control, the motion of the wheels may violate the constraints and the wheels may slip. Consequently, substantial errors can occur in the orientation of the vehicle. A vehicle with N drive wheels has (N - 1) constraints and one degree of freedom. We have developed a new approach tomore » the control of a vehicle with N steerable drive wheels. The novel aspect of our approach is the use of force control. To control the vehicle, we have one degree of freedom for the position on the circle and (N - 1) forces that can be used to reduce errors. Recently, Kankaanranta and Koivo developed a control architecture that allows the force and position degrees of freedom to be decoupled. In the work of Kankaanranta and Koivo the force is an exogenous input. We have made the force endogenous by defining the force in terms of the errors in satisfying the rigid body kinematic constraints. We have applied the control architecture to the HERMIES-III robot and have measured a dramatic reduction in error (more than a factor of 20) compared to motions without force control.« less

Prevalence and trends of drugged driving in Canada.

PubMed

Robertson, Robyn D; Mainegra Hing, Marisela; Pashley, Charlotte R; Brown, Steve W; Vanlaar, Ward G M

2017-02-01

This study evaluates prevalence and trends in drugged driving in Canada based on multiple indicators collected from the Road Safety Monitor (RSM) and Canada's National Fatality Database maintained by the Traffic Injury Research Foundation (TIRF). The objective of this paper is to identify the state of drug-positive driving in Canada, as well as to make comparisons with data from previous years to determine whether changes have occurred. Available data from the RSM on self-reported drugged driving behaviours were collected and analyzed using multivariate techniques in various years spanning from 2002 to 2015. Data from TIRF's National Fatality Database from 2000 to 2012 were also analyzed to evaluate trends and prevalence of drugs in fatally injured drivers across Canada. Additionally, differences among drugged drivers with respect to gender and age were studied. Analyses of the RSM data and of the National Fatality Database showed that, as a whole, the prevalence of drugged driving has remained relatively stable over the past decade, with some changes noticed in specific years for some drug types. Specifically from the RSM, there was a 62.5% increase from the 1.6% of drivers reporting driving within two hours of using marijuana in 2013 to 2.6% in 2015. The analyses of the fatality data revealed a 16.9% increase in the percentage of fatally injured drivers testing positive for drugs between 2000 and 2012 (from 33.56% to 39.24%). Cocaine-positive fatally injured drivers increased from 3.6% in 2000 to 6.2% in 2012. Similarly, marijuana-positive fatally injured drivers increased from 12.8% in 2000 to 19.7% in 2012. Results showed varying characteristics with respect to gender and age among self-reported and fatally injured drugged drivers. Drugged driving behaviours remain prevalent among Canadian drivers and drugs continue to be found in over one-third of tested fatally injured drivers. Although self-reported behaviours have neither decreased nor increased overall in the past decade according to RSM data, with the exception of driving within two hours of using marijuana, data from fatally injured drivers reveal that small, but significant increases in some behaviours have occurred. Copyright © 2016 Elsevier Ltd. All rights reserved.

Associations between motor unit action potential parameters and surface EMG features.

PubMed

Del Vecchio, Alessandro; Negro, Francesco; Felici, Francesco; Farina, Dario

2017-10-01

The surface interference EMG signal provides some information on the neural drive to muscles. However, the association between neural drive to muscle and muscle activation has long been debated with controversial indications due to the unavailability of motor unit population data. In this study, we clarify the potential and limitations of interference EMG analysis to infer motor unit recruitment strategies with an experimental investigation of several concurrently active motor units and of the associated features of the surface EMG. For this purpose, we recorded high-density surface EMG signals during linearly increasing force contractions of the tibialis anterior muscle, up to 70% of maximal force. The recruitment threshold (RT), conduction velocity (MUCV), median frequency (MDF MU ), and amplitude (RMS MU ) of action potentials of 587 motor units from 13 individuals were assessed and associated with features of the interference EMG. MUCV was positively associated with RT ( R 2 = 0.64 ± 0.14), whereas MDF MU and RMS MU showed a weaker relation with RT ( R 2 = 0.11 ± 0.11 and 0.39 ± 0.24, respectively). Moreover, the changes in average conduction velocity estimated from the interference EMG predicted well the changes in MUCV ( R 2 = 0.71), with a strong association to ankle dorsiflexion force ( R 2 = 0.81 ± 0.12). Conversely, both the average EMG MDF and RMS were poorly associated with motor unit recruitment. These results clarify the limitations of EMG spectral and amplitude analysis in inferring the neural strategies of muscle control and indicate that, conversely, the average conduction velocity could provide relevant information on these strategies. NEW & NOTEWORTHY The surface EMG provides information on the neural drive to muscles. However, the associations between EMG features and neural drive have been long debated due to unavailability of motor unit population data. Here, by using novel highly accurate decomposition of the EMG, we related motor unit population behavior to a wide range of voluntary forces. The results fully clarify the potential and limitation of the surface EMG to provide estimates of the neural drive to muscles. Copyright © 2017 the American Physiological Society.

Improved Stability and Stabilization Results for Stochastic Synchronization of Continuous-Time Semi-Markovian Jump Neural Networks With Time-Varying Delay.

PubMed

Wei, Yanling; Park, Ju H; Karimi, Hamid Reza; Tian, Yu-Chu; Jung, Hoyoul; Yanling Wei; Park, Ju H; Karimi, Hamid Reza; Yu-Chu Tian; Hoyoul Jung; Tian, Yu-Chu; Wei, Yanling; Jung, Hoyoul; Karimi, Hamid Reza; Park, Ju H

2018-06-01

Continuous-time semi-Markovian jump neural networks (semi-MJNNs) are those MJNNs whose transition rates are not constant but depend on the random sojourn time. Addressing stochastic synchronization of semi-MJNNs with time-varying delay, an improved stochastic stability criterion is derived in this paper to guarantee stochastic synchronization of the response systems with the drive systems. This is achieved through constructing a semi-Markovian Lyapunov-Krasovskii functional together as well as making use of a novel integral inequality and the characteristics of cumulative distribution functions. Then, with a linearization procedure, controller synthesis is carried out for stochastic synchronization of the drive-response systems. The desired state-feedback controller gains can be determined by solving a linear matrix inequality-based optimization problem. Simulation studies are carried out to demonstrate the effectiveness and less conservatism of the presented approach.

Controllability of Free-piston Stirling Engine/linear Alternator Driving a Dynamic Load

NASA Technical Reports Server (NTRS)

Kankam, M. David; Rauch, Jeffrey S.

1994-01-01

This paper presents the dynamic behavior of a Free-Piston Stirling Engine/linear alternator (FPSE/LA) driving a single-phase fractional horse-power induction motor. The controllability and dynamic stability of the system are discussed by means of sensitivity effects of variations in system parameters, engine controller, operating conditions, and mechanical loading on the induction motor. The approach used expands on a combined mechanical and thermodynamic formulation employed in a previous paper. The application of state-space technique and frequency domain analysis enhances understanding of the dynamic interactions. Engine-alternator parametric sensitivity studies, similar to those of the previous paper, are summarized. Detailed discussions are provided for parametric variations which relate to the engine controller and system operating conditions. The results suggest that the controllability of a FPSE-based power system is enhanced by proper operating conditions and built-in controls.

Compact high-speed reciprocating probe system for measurements in a Hall thruster discharge and plume.

PubMed

Dannenmayer, K; Mazouffre, S

2012-12-01

A compact high-speed reciprocating probe system has been developed in order to perform measurements of the plasma parameters by means of electrostatic probes in the discharge and the plume of a Hall thruster. The system is based on a piezoelectric linear drive that can achieve a speed of up to 350 mm/s over a travel range of 90 mm. Due to the high velocity of the linear drive the probe can be rapidly moved in and out the measurement region in order to minimize perturbation of the thruster discharge due to sputtering of probe material. To demonstrate the impact of the new system, a heated emissive probe, installed on the high-speed translation stage, was used to measure the plasma potential and the electron temperature in the near-field plume of a low power Hall thruster.

Probabilistic vs linear blending approaches to shared control for wheelchair driving.

PubMed

Ezeh, Chinemelu; Trautman, Pete; Devigne, Louise; Bureau, Valentin; Babel, Marie; Carlson, Tom

2017-07-01

Some people with severe mobility impairments are unable to operate powered wheelchairs reliably and effectively, using commercially available interfaces. This has sparked a body of research into "smart wheelchairs", which assist users to drive safely and create opportunities for them to use alternative interfaces. Various "shared control" techniques have been proposed to provide an appropriate level of assistance that is satisfactory and acceptable to the user. Most shared control techniques employ a traditional strategy called linear blending (LB), where the user's commands and wheelchair's autonomous commands are combined in some proportion. In this paper, however, we implement a more generalised form of shared control called probabilistic shared control (PSC). This probabilistic formulation improves the accuracy of modelling the interaction between the user and the wheelchair by taking into account uncertainty in the interaction. In this paper, we demonstrate the practical success of PSC over LB in terms of safety, particularly for novice users.

The electromigration force in metallic bulk

NASA Astrophysics Data System (ADS)

Lodder, A.; Dekker, J. P.

1998-01-01

The voltage induced driving force on a migrating atom in a metallic system is discussed in the perspective of the Hellmann-Feynman force concept, local screening concepts and the linear-response approach. Since the force operator is well defined in quantum mechanics it appears to be only confusing to refer to the Hellmann-Feynman theorem in the context of electromigration. Local screening concepts are shown to be mainly of historical value. The physics involved is completely represented in ab initio local density treatments of dilute alloys and the implementation does not require additional precautions about screening, being typical for jellium treatments. The linear-response approach is shown to be a reliable guide in deciding about the two contributions to the driving force, the direct force and the wind force. Results are given for the wind valence for electromigration in a number of FCC and BCC metals, calculated using an ab initio KKR-Green's function description of a dilute alloy.

A design of driving circuit for star sensor imaging camera

NASA Astrophysics Data System (ADS)

Li, Da-wei; Yang, Xiao-xu; Han, Jun-feng; Liu, Zhao-hui

2016-01-01

The star sensor is a high-precision attitude sensitive measuring instruments, which determine spacecraft attitude by detecting different positions on the celestial sphere. Imaging camera is an important portion of star sensor. The purpose of this study is to design a driving circuit based on Kodak CCD sensor. The design of driving circuit based on Kodak KAI-04022 is discussed, and the timing of this CCD sensor is analyzed. By the driving circuit testing laboratory and imaging experiments, it is found that the driving circuits can meet the requirements of Kodak CCD sensor.

Heliostat field cost reduction by `slope drive' optimization

NASA Astrophysics Data System (ADS)

Arbes, Florian; Weinrebe, Gerhard; Wöhrbach, Markus

2016-05-01

An algorithm to optimize power tower heliostat fields employing heliostats with so-called slope drives is presented. It is shown that a field using heliostats with the slope drive axes configuration has the same performance as a field with conventional azimuth-elevation tracking heliostats. Even though heliostats with the slope drive configuration have a limited tracking range, field groups of heliostats with different axes or different drives are not needed for different positions in the heliostat field. The impacts of selected parameters on a benchmark power plant (PS10 near Seville, Spain) are analyzed.

H1 antihistamines and driving.

PubMed

Popescu, Florin Dan

2008-01-01

Driving performances depend on cognitive, psychomotor and perception functions. The CNS adverse effects of some H1 antihistamines can alter the patient ability to drive. Data from studies using standardized objective cognitive and psychomotor tests (Choice Reaction Time, Critical Flicker Fusion. Digital Symbol Substitution Test), functional brain imaging (Positron Emission Tomography, functional Magnetic Resonance Imaging), neurophysiological studies (Multiple Sleep Latency Test, auditory and visual evoked potentials), experimental simulated driving (driving simulators) and real driving studies (the Highway Driving Test, with the evaluation of the Standard Deviation Lateral Position, and the Car Following Test, with the measurement of the Brake Reaction Time) must be discussed in order to classify a H1 antihistamine as a true non-sedating one.

H1 antihistamines and driving

PubMed Central

Florin-Dan, Popescu

2008-01-01

Driving performances depend on cognitive, psychomotor and perception functions. The CNS adverse effects of some H1 antihistamines can alter the patient ability to drive. Data from studies using standardized objective cognitive and psychomotor tests (Choice Reaction Time, Critical Flicker Fusion, Digital Symbol Substitution Test), functional brain imaging (Positron Emission Tomography, functional Magnetic Resonance Imaging), neurophysiological studies (Multiple Sleep Latency Test, auditory and visual evoked potentials), experimental simulated driving (driving simulators) and real driving studies (the Highway Driving Test, with the evaluation of the Standard Deviation Lateral Position, and the Car Following Test, with the measurement of the Brake Reaction Time) must be discussed in order to classify a H1 antihistamine as a true non-sedating one. PMID:20108503

Many apples a day keep the blues away--daily experiences of negative and positive affect and food consumption in young adults.

PubMed

White, Bonnie A; Horwath, Caroline C; Conner, Tamlin S

2013-11-01

Prior research has focused on the association between negative affect and eating behaviour, often utilizing laboratory or cross-sectional study designs. These studies have inherent limitations, and the association between positive affect and eating behaviour remains relatively unexplored. Therefore, the objective of this study was to investigate the bidirectional relationships between daily negative and positive affective experiences and food consumption in a naturalistic setting among healthy young adults. Daily diary study across 21 days (microlongitudinal, correlational design). A total of 281 young adults with a mean age of 19.9 (± 1.2) years completed an Internet-based daily diary for 21 consecutive days. Each day they reported their negative and positive affect, and their consumption of five specific foods. Hierarchical linear modelling was used to test same-day associations between daily affect and food consumption, and next-day (lagged) associations to determine directionality. Moderating effects of BMI and gender were also examined in exploratory analyses. Analyses of same-day within-person associations revealed that on days when young adults experienced greater positive affect, they reported eating more servings of fruit (p = .002) and vegetables (p < .001). Results of lagged analysis showed that fruits and vegetables predicted improvements in positive affect the next day, suggesting that healthy foods were driving affective experiences and not vice versa. Meaningful changes in positive affect were observed with the daily consumption of approximately 7-8 servings of fruit or vegetables. Eating fruit and vegetables may promote emotional well-being among healthy young adults. © 2013 The British Psychological Society.

Introducing a multivariate model for predicting driving performance: the role of driving anger and personal characteristics.

PubMed

Roidl, Ernst; Siebert, Felix Wilhelm; Oehl, Michael; Höger, Rainer

2013-12-01

Maladaptive driving is an important source of self-inflicted accidents and this driving style could include high speeds, speeding violations, and poor lateral control of the vehicle. The literature suggests that certain groups of drivers, such as novice drivers, males, highly motivated drivers, and those who frequently experience anger in traffic, tend to exhibit more maladaptive driving patterns compared to other drivers. Remarkably, no coherent framework is currently available to describe the relationships and distinct influences of these factors. We conducted two studies with the aim of creating a multivariate model that combines the aforementioned factors, describes their relationships, and predicts driving performance more precisely. The studies employed different techniques to elicit emotion and different tracks designed to explore the driving behaviors of participants in potentially anger-provoking situations. Study 1 induced emotions with short film clips. Study 2 confronted the participants with potentially anger-inducing traffic situations during the simulated drive. In both studies, participants who experienced high levels of anger drove faster and exhibited greater longitudinal and lateral acceleration. Furthermore, multiple linear regressions and path-models revealed that highly motivated male drivers displayed the same behavior independent of their emotional state. The results indicate that anger and specific risk characteristics lead to maladaptive changes in important driving parameters and that drivers with these specific risk factors are prone to experience more anger while driving, which further worsens their driving performance. Driver trainings and anger management courses will profit from these findings because they help to improve the validity of assessments of anger related driving behavior. © 2013.

Does haptic steering guidance instigate speeding? A driving simulator study into causes and remedies.

PubMed

Melman, T; de Winter, J C F; Abbink, D A

2017-01-01

An important issue in road traffic safety is that drivers show adverse behavioral adaptation (BA) to driver assistance systems. Haptic steering guidance is an upcoming assistance system which facilitates lane-keeping performance while keeping drivers in the loop, and which may be particularly prone to BA. Thus far, experiments on haptic steering guidance have measured driver performance while the vehicle speed was kept constant. The aim of the present driving simulator study was to examine whether haptic steering guidance causes BA in the form of speeding, and to evaluate two types of haptic steering guidance designed not to suffer from BA. Twenty-four participants drove a 1.8m wide car for 13.9km on a curved road, with cones demarcating a single 2.2m narrow lane. Participants completed four conditions in a counterbalanced design: no guidance (Manual), continuous haptic guidance (Cont), continuous guidance that linearly reduced feedback gains from full guidance at 125km/h towards manual control at 130km/h and above (ContRF), and haptic guidance provided only when the predicted lateral position was outside a lateral bandwidth (Band). Participants were familiarized with each condition prior to the experimental runs and were instructed to drive as they normally would while minimizing the number of cone hits. Compared to Manual, the Cont condition yielded a significantly higher driving speed (on average by 7km/h), whereas ContRF and Band did not. All three guidance conditions yielded better lane-keeping performance than Manual, whereas Cont and ContRF yielded lower self-reported workload than Manual. In conclusion, continuous steering guidance entices drivers to increase their speed, thereby diminishing its potential safety benefits. It is possible to prevent BA while retaining safety benefits by making a design adjustment either in lateral (Band) or in longitudinal (ContRF) direction. Copyright © 2016. Published by Elsevier Ltd.

Bipolar Electrode Array Embedded in a Polymer Light-Emitting Electrochemical Cell.

PubMed

Gao, Jun; Chen, Shulun; AlTal, Faleh; Hu, Shiyu; Bouffier, Laurent; Wantz, Guillaume

2017-09-20

A linear array of aluminum discs is deposited between the driving electrodes of an extremely large planar polymer light-emitting electrochemical cell (PLEC). The planar PLEC is then operated at a constant bias voltage of 100 V. This promotes in situ electrochemical doping of the luminescent polymer from both the driving electrodes and the aluminum discs. These aluminum discs function as discrete bipolar electrodes (BPEs) that can drive redox reactions at their extremities. Time-lapse fluorescence imaging reveals that p- and n-doping that originated from neighboring BPEs can interact to form multiple light-emitting p-n junctions in series. This provides direct evidence of the working principle of bulk homojunction PLECs. The propagation of p-doping is faster from the BPEs than from the positive driving electrode due to electric field enhancement at the extremities of BPEs. The effect of field enhancement and the fact that the doping fronts only need to travel the distance between the neighboring BPEs to form a light-emitting junction greatly reduce the response time for electroluminescence in the region containing the BPE array. The near simultaneous formation of multiple light-emitting p-n junctions in series causes a measurable increase in cell current. This indicates that the region containing a BPE is much more conductive than the rest of the planar cell despite the latter's greater width. The p- and n-doping originating from the BPEs is initially highly confined. Significant expansion and divergence of doping occurred when the region containing the BPE array became more conductive. The shape and direction of expanded doping strongly suggest that the multiple light-emitting p-n junctions, formed between and connected by the array of metal BPEs, have functioned as a single rod-shaped BPE. This represents a new type of BPE that is formed in situ and as a combination of metal, doped polymers, and forward-biased p-n junctions connected in series.

The importance of self-regulatory and goal-conflicting processes in the avoidance of drunk driving among Greek young drivers.

PubMed

Liourta, Elissavet; van Empelen, Pepijn

2008-05-01

The present study examined self-regulatory and goal-conflicting processes in the avoidance of drunk driving among Greek young drivers. A total of 361 university students in Greece completed a questionnaire, using a retrospective cross-sectional survey design. One-third reported to have driven under the influence of alcohol. Although prior intentions were clearly related to actual avoidance of drunk driving, one out of five respondents had not complied with their intention. An examination of post-intentional correlates of avoidance of drunk driving among positive intenders showed that avoidance of drunk driving was positively related to alcohol limitation plans and alcohol limitation self-efficacy, whereas negative relations were found for goal conflict and behavioural willingness. The present study suggests that people should not only be motivated but also be equipped with self-regulatory strategies aiming at the avoidance of drinking. Finally, goal commitment should be enhanced by increasing the salience of the avoidance goal.

The effects of taboo-related distraction on driving performance.

PubMed

Chan, Michelle; Madan, Christopher R; Singhal, Anthony

2016-07-01

Roadside billboards containing negative and positive emotional content have been shown to influence driving performance, however, the impact of highly arousing taboo information is unknown. Taboo information more reliably evokes emotional arousal and can lead to greater attentional capture due to its inherent 'shock value.' The objective of the present study was to examine driver distraction associated with four types of information presented on roadside billboards: highly arousing taboo words, moderately arousing positive and negative words, and non-arousing neutral words. Participants viewed blocks of taboo, positive, negative and neutral words presented on roadside billboards while operating a driving simulator. They also responded to target (household-related) words by pressing a button on the steering wheel. At the end of the session, a surprise recall task was completed for all the words they saw while driving. Results showed that taboo words captured the most attention as revealed by better memory recall compared to all the other word types. Interestingly, taboo words were associated with better lane control compared to the other word types. We suggest that taboo-related arousal can enhance attentional focus during a complex task like simulated driving. That is, in a highly arousing situation, attention is selectively narrowed to the road ahead, resulting in better lane control. Copyright © 2016 Elsevier B.V. All rights reserved.

CenH3 evolution reflects meiotic symmetry as predicted by the centromere drive model

PubMed Central

Zedek, František; Bureš, Petr

2016-01-01

The centromere drive model explaining rapid evolution of eukaryotic centromeres predicts higher frequency of positive selection acting on centromeric histone H3 (CenH3) in clades with asymmetric meiosis compared to the clades with only symmetric meiosis. However, despite the impression one might get from the literature, this key prediction of the centromere drive model has not only never been confirmed, but it has never been tested, because all the previous studies dealt only with the presence or absence instead of the frequency of positive selection. To provide evidence for or against different frequencies of positively selected CenH3 in asymmetrics and symmetrics, we have inferred the selective pressures acting on CenH3 in seventeen eukaryotic clades, including plants, animals, fungi, ciliates and apicomplexa, using codon-substitution models, and compared the inferred frequencies between asymmetrics and symmetrics in a quantitative manner. We have found that CenH3 has been evolving adaptively much more frequently in clades with asymmetric meiosis compared with clades displaying only symmetric meiosis which confirms the prediction of centromere drive model. Our findings indicate that the evolution of asymmetric meiosis required CenH3 to evolve adaptively more often to counterbalance the negative consequences of centromere drive. PMID:27629066

A model of energetic ion effects on pressure driven tearing modes in tokamaks

DOE PAGES

Halfmoon, M. R.; Brennan, D. P.

2017-06-05

Here, the effects that energetic trapped ions have on linear resistive magnetohydrodynamic (MHD) instabilities are studied in a reduced model that captures the essential physics driving or damping the modes through variations in the magnetic shear. The drift-kinetic orbital interaction of a slowing down distribution of trapped energetic ions with a resistive MHD instability is integrated to a scalar contribution to the perturbed pressure, and entered into an asymptotic matching formalism for the resistive MHD dispersion relation. Toroidal magnetic field line curvature is included to model trapping in the particle distribution, in an otherwise cylindrical model. The focus is onmore » a configuration that is driven unstable to the m/n = 2/1 mode by increasing pressure, where m is the poloidal mode number and n is the toroidal. The particles and pressure can affect the mode both in the core region where there can be low and reversed shear and outside the resonant surface in significant positive shear. The results show that the energetic ions damp and stabilize the mode when orbiting in significant positive shear, increasing the marginal stability boundary. However, the inner core region contribution with low and reversed shear can drive the mode unstable. This effect of shear on the energetic ion pressure contribution is found to be consistent with the literature. These results explain the observation that the 2/1 mode was found to be damped and stabilized by energetic ions in delta δf-MHD simulations of tokamak experiments with positive shear throughout, while the 2/1 mode was found to be driven unstable in simulations of experiments with weakly reversed shear in the core. This is also found to be consistent with related experimental observations of the stability of the 2/1 mode changing significantly with core shear.« less

Nitrogen deposition outweighs climatic variability in driving annual growth rate of canopy beech trees: Evidence from long-term growth reconstruction across a geographic gradient.

PubMed

Gentilesca, Tiziana; Rita, Angelo; Brunetti, Michele; Giammarchi, Francesco; Leonardi, Stefano; Magnani, Federico; van Noije, Twan; Tonon, Giustino; Borghetti, Marco

2018-07-01

In this study, we investigated the role of climatic variability and atmospheric nitrogen deposition in driving long-term tree growth in canopy beech trees along a geographic gradient in the montane belt of the Italian peninsula, from the Alps to the southern Apennines. We sampled dominant trees at different developmental stages (from young to mature tree cohorts, with tree ages spanning from 35 to 160 years) and used stem analysis to infer historic reconstruction of tree volume and dominant height. Annual growth volume (G V ) and height (G H ) variability were related to annual variability in model simulated atmospheric nitrogen deposition and site-specific climatic variables, (i.e. mean annual temperature, total annual precipitation, mean growing period temperature, total growing period precipitation, and standard precipitation evapotranspiration index) and atmospheric CO 2 concentration, including tree cambial age among growth predictors. Generalized additive models (GAM), linear mixed-effects models (LMM), and Bayesian regression models (BRM) were independently employed to assess explanatory variables. The main results from our study were as follows: (i) tree age was the main explanatory variable for long-term growth variability; (ii) GAM, LMM, and BRM results consistently indicated climatic variables and CO 2 effects on G V and G H were weak, therefore evidence of recent climatic variability influence on beech annual growth rates was limited in the montane belt of the Italian peninsula; (iii) instead, significant positive nitrogen deposition (N dep ) effects were repeatedly observed in G V and G H ; the positive effects of N dep on canopy height growth rates, which tended to level off at N dep values greater than approximately 1.0 g m -2  y -1 , were interpreted as positive impacts on forest stand above-ground net productivity at the selected study sites. © 2018 John Wiley & Sons Ltd.

Production of Internal Transport Barriers via self-generated flows in Alcator C-Mod

NASA Astrophysics Data System (ADS)

Fiore, Catherine L.

2011-10-01

New results suggest that changes observed in the intrinsic toroidal rotation influence ITB formation in Alcator C-Mod that arise when the resonance for ICRF minority heating is positioned off-axis at or outside of the plasma half-radius. These ITBs form in a reactor relevant regime, without particle or momentum injection, with Ti ~Te, and with monotonic q profiles (qmin < 1). C-Mod H-mode plasmas exhibit strong intrinsic co-current rotation that increases with increasing stored energy without external drive. With the resonance position off-axis, the rotation decreases in the center of the plasma resulting in a radial rotation profile with a central well which deepens and moves farther off-axis when the ICRF resonance is at the plasma half-radius. This profile results in strong ExB shear (>1.5x105 Rad/sec) in the region where the ITB foot is observed. The self generated ExB shearing increases rapidly after the H-mode transition in off-axis ICRF heated discharges, before other profile changes are observed. Gyrokinetic analyses indicate that this spontaneous shearing rate is comparable to the linear ITG growth rate at the ITB location and may be responsible for stabilizing the underlying turbulence. Detailed measurement of the ion temperature demonstrates that the radial profile also flattens as the ICRF resonance position moves off axis. This decreases R/LTi in the barrier region, lessening the drive for the ITG turbulence and the resulting particle transport. The reduction in particle transport resulting from increase in core stability allows the neoclassical pinch to peak the density and pressure on axis. This suggests that spontaneous rotation is a potential tool for plasma profile control in reactor plasmas. The experimental results and corresponding gyrokinetic study will be presented. US-DoE DE-FC02-99ER54512 and DE-FG03-96ER54373.

A model of energetic ion effects on pressure driven tearing modes in tokamaks

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

Halfmoon, M. R.; Brennan, D. P.

Here, the effects that energetic trapped ions have on linear resistive magnetohydrodynamic (MHD) instabilities are studied in a reduced model that captures the essential physics driving or damping the modes through variations in the magnetic shear. The drift-kinetic orbital interaction of a slowing down distribution of trapped energetic ions with a resistive MHD instability is integrated to a scalar contribution to the perturbed pressure, and entered into an asymptotic matching formalism for the resistive MHD dispersion relation. Toroidal magnetic field line curvature is included to model trapping in the particle distribution, in an otherwise cylindrical model. The focus is onmore » a configuration that is driven unstable to the m/n = 2/1 mode by increasing pressure, where m is the poloidal mode number and n is the toroidal. The particles and pressure can affect the mode both in the core region where there can be low and reversed shear and outside the resonant surface in significant positive shear. The results show that the energetic ions damp and stabilize the mode when orbiting in significant positive shear, increasing the marginal stability boundary. However, the inner core region contribution with low and reversed shear can drive the mode unstable. This effect of shear on the energetic ion pressure contribution is found to be consistent with the literature. These results explain the observation that the 2/1 mode was found to be damped and stabilized by energetic ions in delta δf-MHD simulations of tokamak experiments with positive shear throughout, while the 2/1 mode was found to be driven unstable in simulations of experiments with weakly reversed shear in the core. This is also found to be consistent with related experimental observations of the stability of the 2/1 mode changing significantly with core shear.« less

Drive beam stabilisation in the CLIC Test Facility 3

NASA Astrophysics Data System (ADS)

Malina, L.; Corsini, R.; Persson, T.; Skowroński, P. K.; Adli, E.

2018-06-01

The proposed Compact Linear Collider (CLIC) uses a high intensity, low energy drive beam to produce the RF power needed to accelerate a lower intensity main beam with 100 MV/m gradient. This scheme puts stringent requirements on drive beam stability in terms of phase, energy and current. The consequent experimental work was carried out in CLIC Test Facility CTF3. In this paper, we present a novel analysis technique in accelerator physics to find beam drifts and their sources in the vast amount of the continuously gathered signals. The instability sources are identified and adequately mitigated either by hardware improvements or by implementation and commissioning of various feedbacks, mostly beam-based. The resulting drive beam stability is of 0.2°@ 3 GHz in phase, 0.08% in relative beam energy and about 0.2% beam current. Finally, we propose a stabilisation concept for CLIC to guarantee the main beam stability.

The Effect of Drive Signal Limiting on High Cycle Fatigue Life Analysis

NASA Technical Reports Server (NTRS)

Kihm, Frederic; Rizzi, Stephen A.

2014-01-01

It is common practice to assume a Gaussian distribution of both the input acceleration and the response when modeling random vibration tests. In the laboratory, however, shaker controllers often limit the drive signal to prevent high amplitude peaks. The high amplitudes may either be truncated at a given level (socalled brick wall limiting or abrupt clipping), or compressed (soft limiting), resulting in drive signals which are no longer Gaussian. The paper first introduces several methods for limiting a drive signal, including brick wall limiting and compression. The limited signal is then passed through a linear time-invariant system representing a device under test. High cycle fatigue life predictions are subsequently made using spectral fatigue and rainflow cycle counting schemes. The life predictions are compared with those obtained from unclipped input signals. Some guidelines are provided to help the test engineer decide how clipping should be applied under different test scenarios.

Inversion for the driving forces of plate tectonics

NASA Technical Reports Server (NTRS)

Richardson, R. M.

1983-01-01

Inverse modeling techniques have been applied to the problem of determining the roles of various forces that may drive and resist plate tectonic motions. Separate linear inverse problems have been solved to find the best fitting pole of rotation for finite element grid point velocities and to find the best combination of force models to fit the observed relative plate velocities for the earth's twelve major plates using the generalized inverse operator. Variance-covariance data on plate motion have also been included. Results emphasize the relative importance of ridge push forces in the driving mechanism. Convergent margin forces are smaller by at least a factor of two, and perhaps by as much as a factor of twenty. Slab pull, apparently, is poorly transmitted to the surface plate as a driving force. Drag forces at the base of the plate are smaller than ridge push forces, although the sign of the force remains in question.

Estimating Driving Performance Based on EEG Spectrum Analysis

NASA Astrophysics Data System (ADS)

Lin, Chin-Teng; Wu, Ruei-Cheng; Jung, Tzyy-Ping; Liang, Sheng-Fu; Huang, Teng-Yi

2005-12-01

The growing number of traffic accidents in recent years has become a serious concern to society. Accidents caused by driver's drowsiness behind the steering wheel have a high fatality rate because of the marked decline in the driver's abilities of perception, recognition, and vehicle control abilities while sleepy. Preventing such accidents caused by drowsiness is highly desirable but requires techniques for continuously detecting, estimating, and predicting the level of alertness of drivers and delivering effective feedbacks to maintain their maximum performance. This paper proposes an EEG-based drowsiness estimation system that combines electroencephalogram (EEG) log subband power spectrum, correlation analysis, principal component analysis, and linear regression models to indirectly estimate driver's drowsiness level in a virtual-reality-based driving simulator. Our results demonstrated that it is feasible to accurately estimate quantitatively driving performance, expressed as deviation between the center of the vehicle and the center of the cruising lane, in a realistic driving simulator.

Wire-Guide Manipulator For Automated Welding

NASA Technical Reports Server (NTRS)

Morris, Tim; White, Kevin; Gordon, Steve; Emerich, Dave; Richardson, Dave; Faulkner, Mike; Stafford, Dave; Mccutcheon, Kim; Neal, Ken; Milly, Pete

1994-01-01

Compact motor drive positions guide for welding filler wire. Drive part of automated wire feeder in partly or fully automated welding system. Drive unit contains three parallel subunits. Rotations of lead screws in three subunits coordinated to obtain desired motions in three degrees of freedom. Suitable for both variable-polarity plasma arc welding and gas/tungsten arc welding.

Confronting Drowsy Driving: The American Academy of Sleep Medicine Perspective.

PubMed

Watson, Nathaniel F; Morgenthaler, Timothy; Chervin, Ronald; Carden, Kelly; Kirsch, Douglas; Kristo, David; Malhotra, Raman; Martin, Jennifer; Ramar, Kannan; Rosen, Ilene; Weaver, Terri; Wise, Merrill

2015-11-15

Drowsy driving is a serious public health concern which is often difficult for individual drivers to identify. While it is important for drivers to understand the causes of drowsy driving, there is still insufficient scientific knowledge and public education to prevent drowsy driving. As a result, the AASM is calling upon institutions and policy makers to increase public awareness and improve education on the issue, so our society can better recognize and prevent drowsy driving. The AASM has adopted a position statement to educate both healthcare providers and the general public about drowsy driving risks and countermeasures. © 2015 American Academy of Sleep Medicine.

Awareness of driving while sleepy and road traffic accidents: prospective study in GAZEL cohort.

PubMed

Nabi, Hermann; Guéguen, Alice; Chiron, Mireille; Lafont, Sylviane; Zins, Marie; Lagarde, Emmanuel

2006-07-08

To examine the association between self assessed driving while sleepy and the risk of serious road traffic accidents (RTAs). Prospective cohort study. France. 13 299 of the 19 894 living members of the GAZEL cohort, workers and recent retirees of a French national utility company followed up since 1989. Frequency of driving while sleepy in the previous 12 months, reported in 2001; rate ratios for serious RTAs in 2001-3, estimated by using generalised linear Poisson regression models with time dependent covariates. The risk of serious RTAs increased proportionally with the frequency of self reported driving while sleepy. After adjustment for sociodemographic characteristics, driving behaviour variables, work conditions, retirement, medical conditions and treatments, depressive symptoms, and sleep disorders, the adjusted rate ratios of serious RTAs for participants who reported driving while sleepy in the previous 12 months "a few times" or "once a month or more often" were 1.5 (95% confidence interval 1.2 to 2.0) and 2.9 (1.3 to 6.3) respectively compared with those who reported not driving while sleepy over the same period. These associations were not explained by any reported sleep disorders. Self assessed driving while sleepy was a powerful predictor of serious RTAs, suggesting that drivers' awareness of their sleepiness while driving is not sufficient to prevent them from having RTAs. Messages on prevention should therefore focus on convincing sleepy drivers to stop driving and sleep before resuming their journey.

Cryogenic Scan Mechanism for Fourier Transform Spectrometer

NASA Technical Reports Server (NTRS)

Brasunas, John C.; Francis, John L.

2011-01-01

A compact and lightweight mechanism has been developed to accurately move a Fourier transform spectrometer (FTS) scan mirror (a cube corner) in a near-linear fashion with near constant speed at cryogenic temperatures. This innovation includes a slide mechanism to restrict motion to one dimension, an actuator to drive the motion, and a linear velocity transducer (LVT) to measure the speed. The cube corner mirror is double-passed in one arm of the FTS; double-passing is required to compensate for optical beam shear resulting from tilting of the moving cube corner. The slide, actuator, and LVT are off-the-shelf components that are capable of cryogenic vacuum operation. The actuator drives the slide for the required travel of 2.5 cm. The LVT measures translation speed. A proportional feedback loop compares the LVT voltage with the set voltage (speed) to derive an error signal to drive the actuator and achieve near constant speed. When the end of the scan is reached, a personal computer reverses the set voltage. The actuator and LVT have no moving parts in contact, and have magnetic properties consistent with cryogenic operation. The unlubricated slide restricts motion to linear travel, using crossed roller bearings consistent with 100-million- stroke operation. The mechanism tilts several arc seconds during transport of the FTS mirror, which would compromise optical fringe efficiency when using a flat mirror. Consequently, a cube corner mirror is used, which converts a tilt into a shear. The sheared beam strikes (at normal incidence) a flat mirror at the end of the FTS arm with the moving mechanism, thereby returning upon itself and compensating for the shear

Enhanced vegetation growth peak and its key mechanisms

NASA Astrophysics Data System (ADS)

Huang, K.; Xia, J.; Wang, Y.; Ahlström, A.; Schwalm, C.; Huntzinger, D. N.; Chen, J.; Cook, R. B.; Fang, Y.; Fisher, J. B.; Jacobson, A. R.; Michalak, A.; Schaefer, K. M.; Wei, Y.; Yan, L.; Luo, Y.

2017-12-01

It remains unclear that whether and how the vegetation growth peak has been shifted globally during the past three decades. Here we used two global datasets of gross primary productivity (GPP) and a satellite-derived Normalized Difference Vegetation Index (NDVI) to characterize recent changes in seasonal peak vegetation growth. The attribution of changes in peak growth to their driving factors was examined with several datasets. We demonstrated that the growth peak of global vegetation has been linearly increasing during the past three decades. About 65% of this trend is evenly explained by the expanding croplands (21%), rising atmospheric [CO2] (22%), and intensifying nitrogen deposition (22%). The contribution of expanding croplands to the peak growth trend was substantiated by measurements from eddy-flux towers, sun-induced chlorophyll fluorescence and a global database of plant traits, all of which demonstrated that croplands have a higher photosynthetic capacity than other vegetation types. The contribution of rising atmospheric [CO2] and nitrogen deposition are consistent with the positive response of leaf growth to elevated [CO2] (25%) and nitrogen addition (8%) from 346 manipulated experiments. The positive effect of rising atmospheric [CO2] was also well captured by 15 terrestrial biosphere models. However, most models underestimated the contributions of land-cover change and nitrogen deposition, but overestimated the positive effect of climate change.

The effect of varying levels of vehicle automation on drivers' lane changing behaviour.

PubMed

Madigan, Ruth; Louw, Tyron; Merat, Natasha

2018-01-01

Much of the Human Factors research into vehicle automation has focused on driver responses to critical scenarios where a crash might occur. However, there is less knowledge about the effects of vehicle automation on drivers' behaviour during non-critical take-over situations, such as driver-initiated lane-changing or overtaking. The current driving simulator study, conducted as part of the EC-funded AdaptIVe project, addresses this issue. It uses a within-subjects design to compare drivers' lane-changing behaviour in conventional manual driving, partially automated driving (PAD) and conditionally automated driving (CAD). In PAD, drivers were required to re-take control from an automated driving system in order to overtake a slow moving vehicle, while in CAD, the driver used the indicator lever to initiate a system-performed overtaking manoeuvre. Results showed that while drivers' acceptance of both the PAD and CAD systems was high, they generally preferred CAD. A comparison of overtaking positions showed that drivers initiated overtaking manoeuvres slightly later in PAD than in manual driving or CAD. In addition, when compared to conventional driving, drivers had higher deviations in lane positioning and speed, along with higher lateral accelerations during lane changes following PAD. These results indicate that even in situations which are not time-critical, drivers' vehicle control after automation is degraded compared to conventional driving.

The effect of varying levels of vehicle automation on drivers’ lane changing behaviour

PubMed Central

Louw, Tyron; Merat, Natasha

2018-01-01

Much of the Human Factors research into vehicle automation has focused on driver responses to critical scenarios where a crash might occur. However, there is less knowledge about the effects of vehicle automation on drivers’ behaviour during non-critical take-over situations, such as driver-initiated lane-changing or overtaking. The current driving simulator study, conducted as part of the EC-funded AdaptIVe project, addresses this issue. It uses a within-subjects design to compare drivers’ lane-changing behaviour in conventional manual driving, partially automated driving (PAD) and conditionally automated driving (CAD). In PAD, drivers were required to re-take control from an automated driving system in order to overtake a slow moving vehicle, while in CAD, the driver used the indicator lever to initiate a system-performed overtaking manoeuvre. Results showed that while drivers’ acceptance of both the PAD and CAD systems was high, they generally preferred CAD. A comparison of overtaking positions showed that drivers initiated overtaking manoeuvres slightly later in PAD than in manual driving or CAD. In addition, when compared to conventional driving, drivers had higher deviations in lane positioning and speed, along with higher lateral accelerations during lane changes following PAD. These results indicate that even in situations which are not time-critical, drivers’ vehicle control after automation is degraded compared to conventional driving. PMID:29466402

Assessing the driving performance of older adult drivers: on-road versus simulated driving.

PubMed

Lee, Hoe C; Cameron, Don; Lee, Andy H

2003-09-01

To validate a laboratory-based driving simulator in measuring on-road driving performance, 129 older adult drivers were assessed with both the simulator and an on-road test. The driving performance of the participants was gauged by appropriate and reliable age-specific assessment criteria, which were found to be negatively correlated with age. Using principal component analysis, two performance indices were developed from the criteria to represent the overall performance in simulated driving and the on-road assessment. There was significant positive association between the two indices, with the simulated driving performance index explaining over two-thirds of the variability of the on-road driving performance index, after adjustment for age and gender of the drivers. The results supported the validity of the driving simulator and it is a safer and more economical method than the on-road testing to assess the driving performance of older adult drivers.

Perception of traffic accident risk and decision to drive under light alcohol consumption--a double-blind experimental study.

PubMed

Frick, U; Rehm, J; Knoll, A; Reifinger, M; Hasford, J

2000-01-01

Public traffic safety campaigns in Germany have focussed on the changing risk perception of young drivers. While there is some consensus that perceptions of risk affect driving, less is understood about the relationship and interaction of alcohol consumption and risk perception on the decision to drive. We examined the influence of light alcohol consumption on risk perception and decision to drive, and the interaction of alcohol consumption and cognitive feedback on the handicapping effect of alcohol on risk perception and decision to drive. In a double-blind block-randomized experimental study of 104 young drivers between 19 and 24 years of age, with two experimentally manipulated independent factors of alcohol consumption (three levels: 0% BAC, 0.015% BAC, 0.03% BAC) and feedback (positive or negative), we assessed three dependent variables: perception of traffic accident risk, subjective judgement about driving-relevant cognitive performance, decision to drive a car. Analyses of variance and covariance were used to analyze differences between levels of experimental factors. We found that persons with 0.015 BAC performed better than persons in both other alcohol conditions on the standardized risk perception task. Perceived handicap of driving was significantly more pronounced for negative feedback compared to positive feedback with no influence of the level of alcohol consumption. No significant influence on decision to drive was found of either level of alcohol consumption, feedback or sex. Decision to drive in young drivers could not be influenced by feedback or light consumption. Public health approaches have to find better determining factors.

A virtual reality system for arm and hand rehabilitation

NASA Astrophysics Data System (ADS)

Luo, Zhiqiang; Lim, Chee Kian; Chen, I.-Ming; Yeo, Song Huat

2011-03-01

This paper presents a virtual reality (VR) system for upper limb rehabilitation. The system incorporates two motion track components, the Arm Suit and the Smart Glove which are composed of a range of the optical linear encoders (OLE) and the inertial measurement units (IMU), and two interactive practice applications designed for driving users to perform the required functional and non-functional motor recovery tasks. We describe the technique details about the two motion track components and the rational to design two practice applications. The experiment results show that, compared with the marker-based tracking system, the Arm Suit can accurately track the elbow and wrist positions. The repeatability of the Smart Glove on measuring the five fingers' movement can be satisfied. Given the low cost, high accuracy and easy installation, the system thus promises to be a valuable complement to conventional therapeutic programs offered in rehabilitation clinics and at home.

A colorimetric and fluorogenic probe for bisulfite using benzopyrylium as the recognition unit.

PubMed

Zhang, Yun; Zhang, Xiangwen; Yang, Xiao-Feng; Zhang, Juan

2017-11-01

A coumarin-benzopyrylium (CB) platform has been developed for the colorimetric and fluorogenic detection of bisulfite. The proposed probe utilizes coumarin as the fluorophore and positively charged benzopyrylium as the reaction site. The method employs the nucleophilic addition of bisulfite to the benzopyrylium moiety of CB to inactivate the electron-deficient oxonium ion. The driving force for photo-induced electron transfer is considerably diminished, thereby promoting the emission intensity of the coumarin fluorophore. The fluorescence intensity at 510 nm is linear with bisulfite concentration over a range of 0.2-7.5 μM with a detection limit of 42 nM (3δ). CB shows a rapid response (within 30 s) and high selectivity and sensitivity for bisulfite. Preliminary studies show that CB has great potential for bisulfite detection in real samples and in living cells. Copyright © 2017 John Wiley & Sons, Ltd.

Conscientious personality and young drivers’ crash risk

PubMed Central

Ehsani, Johnathon P.; Li, Kaigang; Simons-Morton, Bruce; Tree-McGrath, Cheyenne Fox; Perlus, Jessamyn; O’Brien, Fearghal; Klauer, Sheila G.

2015-01-01

Introduction Personality characteristics are associated with many risk behaviors. However, the relationship between personality traits, risky driving behavior, and crash risk is poorly understood. The purpose of this study was to examine the association between personality, risky driving behavior and crashes and near-crashes, using naturalistic driving research methods. Method Participants’ driving exposure, kinematic risky driving (KRD), high-risk secondary task engagement, and the frequency of crashes and near-crashes (CNC) were assessed over the first 18 months of licensure using naturalistic driving methods. A personality survey (NEO-Five Factor Inventory) was administered at baseline. The association between personality characteristics, KRD rate, secondary task engagement rate and CNC rate was estimated using a linear regression model. Mediation analysis was conducted to examine if participants’ KRD rate or secondary task engagement rate mediated the relationship between personality and CNC. Data were collected as part of the Naturalistic Teen Driving Study. Results Conscientiousness was marginally negatively associated with CNC (path c = −0.034, p = .09) and both potential mediators KRD (path a = −0.040, p = .09) and secondary task engagement while driving (path a = −0.053, p = .03). KRD, but not secondary task engagement, was found to mediate (path b = 0.376, p = .02) the relationship between conscientiousness and CNC (path c’ = −0.025, p = .20). Conclusions Using objective measures of driving behavior and a widely used personality construct, these findings present a causal pathway through which personality and risky driving are associated with CNC. Specifically, more conscientious teenage drivers engaged in fewer risky driving maneuvers, suffered fewer CNC. Practical Applications Part of the variability in crash-risk observed among newly licensed teenage drivers can be explained by personality. Parents and driving instructors may take teenage drivers’ personality into account when providing guidance, and establishing norms and expectations about driving. PMID:26403906

Conscientious personality and young drivers' crash risk.

PubMed

Ehsani, Johnathon P; Li, Kaigang; Simons-Morton, Bruce G; Fox Tree-McGrath, Cheyenne; Perlus, Jessamyn G; O'Brien, Fearghal; Klauer, Sheila G

2015-09-01

Personality characteristics are associated with many risk behaviors. However, the relationship between personality traits, risky driving behavior, and crash risk is poorly understood. The purpose of this study was to examine the association between personality, risky driving behavior, and crashes and near-crashes, using naturalistic driving research methods. Participants' driving exposure, kinematic risky driving (KRD), high-risk secondary task engagement, and the frequency of crashes and near-crashes (CNC) were assessed over the first 18months of licensure using naturalistic driving methods. A personality survey (NEO-Five Factor Inventory) was administered at baseline. The association between personality characteristics, KRD rate, secondary task engagement rate, and CNC rate was estimated using a linear regression model. Mediation analysis was conducted to examine if participants' KRD rate or secondary task engagement rate mediated the relationship between personality and CNC. Data were collected as part of the Naturalistic Teen Driving Study. Conscientiousness was marginally negatively associated with CNC (path c=-0.034, p=.09) and both potential mediators KRD (path a=-0.040, p=.09) and secondary task engagement while driving (path a=-0.053, p=.03). KRD, but not secondary task engagement, was found to mediate (path b=0.376, p=.02) the relationship between conscientiousness and CNC (path c'=-0.025, p=.20). Using objective measures of driving behavior and a widely used personality construct, these findings present a causal pathway through which personality and risky driving are associated with CNC. Specifically, more conscientious teenage drivers engaged in fewer risky driving maneuvers, and suffered fewer CNC. Part of the variability in crash risk observed among newly licensed teenage drivers can be explained by personality. Parents and driving instructors may take teenage drivers' personality into account when providing guidance, and establishing norms and expectations about driving. Published by Elsevier Ltd.

Predicting perceived safety to drive the morning after drinking: The importance of hangover symptoms.

PubMed

Cameron, Elaine; French, David P

2016-07-01

People driving the day after drinking are at risk of impaired performance and accidents due to continued intoxication or the effects of alcohol hangover. Drivers are poor at estimating their own blood alcohol concentration, and some drive despite believing they are over the legal limit. It is therefore important to identify other factors influencing perceived ability to drive 'the morning after'. This study tested how accurately participants estimated their legal driving status, and the contribution of beliefs and hangover symptoms to the prediction of perceived driving safety. This cross-sectional study involved 193 students completing a questionnaire and alcohol breath test the morning after heavy alcohol consumption. Indicators of subjective intoxication, severity of hangover symptoms, estimated legal status and perceived safety to drive were measured. A hierarchical linear regression analysis was conducted. No participants thought they were under the English legal limit when they were not, and 47% thought they were over the limit when they were in fact legally permissible to drive. However, 20% of those believing they were over the limit nevertheless rated themselves as safe to drive. Hangover symptoms added 17% variance to the prediction of perceived safety to drive, over and above objective and subjective measures of intoxication. Perceived severity of hangover symptoms influence beliefs about driving ability: When judging safety to drive, people experiencing less severe symptoms believe they are less impaired. If this finding is robust, health promotion campaigns should aim to correct this misapprehension. [Cameron E, French D. Predicting perceived safety to drive the morning after drinking: The importance of hangover symptoms. Drug Alcohol Rev 2016;35:442-446]. © 2015 Australasian Professional Society on Alcohol and other Drugs.

Combustion Instabilities In Solid Propellant Rocket Motors

DTIC Science & Technology

2004-01-01

instability in a self-excited system, sketched in Figure 1.5(a). In contrast, the initial transient in a linear system forced by an invariant external agent ...because the driving agent supplies only ¯nite power. (a) (b) Figure 1.5. Transient behavior of (a) Self Excited Linearly Unstable Motions; (b) Forced...the vibration of a Helmholtz resonator obtained, for example, by blowing over the open end of a bottle. The cause in a combustion chamber may be the

Prototype Solid State Induction Modulator for SLAC NLC

NASA Astrophysics Data System (ADS)

Cassel, R. L.; DeLamare, J. E.; Nguyen, M. N.; Pappas, G. C.; Cook, E.

2002-08-01

The Next Linear Collider accelerator proposal at SLAC requires a high efficiency, highly reliable, and low cost pulsed power modulator to drive the X band klystrons. The present NLC envisions a solid-state induction modulator design to drive up to 8 klystrons to 500kV for 3muS at 120 PPS with one modulator (>1,000 megawatt pulse, 500kW average). A prototype modulator is presently under construction, which well power 4 each 5045 SLAC klystron to greater than 380 kV for 3muS (>600 megawatt pulse, >300 kW Ave.). The modulator will be capable of driving the 8 each X band klystrons when they become available. The paper covers the design, construction, fabrication and preliminary testing of the prototype modulator.

Reverse matrix converter control method for PMSM drives using DPC

NASA Astrophysics Data System (ADS)

Bak, Yeongsu; Lee, Kyo-Beum

2018-05-01

This paper proposes a control method for a reverse matrix converter (RMC) that drives a three-phase permanent magnet synchronous motor (PMSM). In this proposed method, direct power control (DPC) is used to control the voltage source rectifier of the RMC. The RMC is an indirect matrix converter operating in the boost mode, in which the power-flow directions of the input and output are switched. It has a minimum voltage transfer ratio of 1/0.866 in a linear-modulation region. In this paper, a control method that uses DPC as an additional control method is proposed in order to control the RMC driving a PMSM in the output stage. Simulations and experimental results verify the effectiveness of the proposed control method.

A rod type linear ultrasonic motor utilizing longitudinal traveling waves: proof of concept

NASA Astrophysics Data System (ADS)

Wang, Liang; Wielert, Tim; Twiefel, Jens; Jin, Jiamei; Wallaschek, Jörg

2017-08-01

This paper proposes a non-resonant linear ultrasonic motor utilizing longitudinal traveling waves. The longitudinal traveling waves in the rod type stator are generated by inducing longitudinal vibrations at one end of the waveguide and eliminating reflections at the opposite end by a passive damper. Considering the Poisson’s effect, the stator surface points move on elliptic trajectories and the slider is driven forward by friction. In contrast to many other flexural traveling wave linear ultrasonic motors, the driving direction of the proposed motor is identical to the wave propagation direction. The feasibility of the motor concept is demonstrated theoretically and experimentally. First, the design and operation principle of the motor are presented in detail. Then, the stator is modeled utilizing the transfer matrix method and verified by experimental studies. In addition, experimental parameter studies are carried out to identify the motor characteristics. Finally, the performance of the proposed motor is investigated. Overall, the results indicate very dynamic drive characteristics. The motor prototype achieves a maximum mean velocity of 115 mm s-1 and a maximum load of 0.25 N. Thereby, the start-up and shutdown times from the maximum speed are lower than 5 ms.

Simulations and measurements of hot-electron generation driven by the multibeam two-plasmon-decay instability

NASA Astrophysics Data System (ADS)

Follett, R. K.; Myatt, J. F.; Shaw, J. G.; Michel, D. T.; Solodov, A. A.; Edgell, D. H.; Yaakobi, B.; Froula, D. H.

2017-10-01

Multibeam experiments relevant to direct-drive inertial confinement fusion show the importance of nonlinear saturation mechanisms in the common-wave two-plasmon-decay (TPD) instability. Planar-target experiments on the OMEGA laser used hard x-ray measurements to study the influence of the linear common-wave growth rate on TPD-driven hot-electron production in two drive-beam configurations and over a range of overlapped laser intensities from 3.6 to 15.2 × 1014 W/cm2. The beam configuration with the larger linear common-wave growth rate had a lower intensity threshold for the onset of hot-electron production, but the linear growth rate made no significant impact on hot-electron production at high intensities. The experiments were modeled in 3-D using a hybrid code LPSE (laser plasma simulation environment) that combines a wave solver with a particle tracker to self-consistently calculate the electron velocity distribution and evolve electron Landau damping. Good quantitative agreement was obtained between the simulated and measured hot-electron distributions using a novel technique to account for macroscopic spatial and temporal variations that were present in the experiments.

Electro-Mechanical Actuator. DC Resonant Link Controller

NASA Technical Reports Server (NTRS)

Schreiner, Kenneth E.

1996-01-01

This report summarizes the work performed on the 68 HP electro-mechanical actuator (EMA) system developed on NASA contract for the Electrical Actuation (ELA) Technology Bridging Program. The system was designed to demonstrate the capability of large, high power linear ELAs for applications such as Thrust Vector Control (TVC) on rocket engines. It consists of a motor controller, drive electronics and a linear actuator capable of up to 32,00 lbs loading at 7.4 inches/second. The drive electronics are based on the Resonant DC link concept and operate at a nominal frequency of 55 kHz. The induction motor is a specially designed high speed, low inertia motor capable of a 68 peak HP. The actuator was originally designed by MOOG Aerospace under an internal R & D program to meet Space Shuttle Main Engine (SSME) TVC requirements. The design was modified to meet this programs linear rate specification of 7.4 inches/second. The motor and driver were tested on a dynamometer at the Martin Marietta Space Systems facility. System frequency response, step response and force-velocity tests were conducted at the MOOG Aerospace facility. A complete description of the system and all test results can be found in the body of the report.

Simulations and measurements of hot-electron generation driven by the multibeam two-plasmon-decay instability

DOE PAGES

Follett, R. K.; Myatt, J. F.; Shaw, J. G.; ...

2017-10-30

We report that multiple-beam experiments relevant to direct-drive inertial confinement fusion show the importance of nonlinear saturation mechanisms in the common-wave two-plasmon-decay (TPD) instability. Planar target experiments on the OMEGA laser used hard-x-ray measurements to study the influence of the linear common-wave growth rate on TPD driven hot-electron production in two drive beam configurations and over a range of overlapped laser intensities from 3.6 to 15.2 x 10 14 W/cm 2. The beam configuration with the larger linear common-wave growth rate had a lower intensity threshold for the onset of hot-electron production, but the linear growth rate did not havemore » a significant impact on hot-electron production at high intensities. The experiments were modeled in 3-D using a hybrid code (LPSE) that combines a wave solver with a particle tracker to self-consistently calculate the electron velocity distribution and evolve electron Landau damping. Finally, good quantitative agreement was obtained between the simulated and measured hotel-electron distributions using a novel technique to account for macroscopic spatial and temporal variations that are present in the experiments.« less

Simulations and measurements of hot-electron generation driven by the multibeam two-plasmon-decay instability

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

Follett, R. K.; Myatt, J. F.; Shaw, J. G.

We report that multiple-beam experiments relevant to direct-drive inertial confinement fusion show the importance of nonlinear saturation mechanisms in the common-wave two-plasmon-decay (TPD) instability. Planar target experiments on the OMEGA laser used hard-x-ray measurements to study the influence of the linear common-wave growth rate on TPD driven hot-electron production in two drive beam configurations and over a range of overlapped laser intensities from 3.6 to 15.2 x 10 14 W/cm 2. The beam configuration with the larger linear common-wave growth rate had a lower intensity threshold for the onset of hot-electron production, but the linear growth rate did not havemore » a significant impact on hot-electron production at high intensities. The experiments were modeled in 3-D using a hybrid code (LPSE) that combines a wave solver with a particle tracker to self-consistently calculate the electron velocity distribution and evolve electron Landau damping. Finally, good quantitative agreement was obtained between the simulated and measured hotel-electron distributions using a novel technique to account for macroscopic spatial and temporal variations that are present in the experiments.« less

Rotation motion of designed nano-turbine.

PubMed

Li, Jingyuan; Wang, Xiaofeng; Zhao, Lina; Gao, Xingfa; Zhao, Yuliang; Zhou, Ruhong

2014-07-28

Construction of nano-devices that can generate controllable unidirectional rotation is an important part of nanotechnology. Here, we design a nano-turbine composed of carbon nanotube and graphene nanoblades, which can be driven by fluid flow. Rotation motion of nano-turbine is quantitatively studied by molecular dynamics simulations on this model system. A robust linear relationship is achieved with this nano-turbine between its rotation rate and the fluid flow velocity spanning two orders of magnitude, and this linear relationship remains intact at various temperatures. More interestingly, a striking difference from its macroscopic counterpart is identified: the rotation rate is much smaller (by a factor of ~15) than that of the macroscopic turbine with the same driving flow. This discrepancy is shown to be related to the disruption of water flow at nanoscale, together with the water slippage at graphene surface and the so-called "dragging effect". Moreover, counterintuitively, the ratio of "effective" driving flow velocity increases as the flow velocity increases, suggesting that the linear dependence on the flow velocity can be more complicated in nature. These findings may serve as a foundation for the further development of rotary nano-devices and should also be helpful for a better understanding of the biological molecular motors.

Development trends in IR detector coolers

NASA Astrophysics Data System (ADS)

Mai, M.; Rühlich, I.; Wiedmann, Th.; Rosenhagen, C.

2009-05-01

For different IR application specific cooler requirements are needed to achieve best performance on system level. Handheld applications require coolers with highest efficiency and lowest weight. For application with continuous operation, i.e. border surveillance or homeland security, a very high MTTF is mandatory. Space applications additionally require extremely high reliability. In other application like fighter aircraft sufficient cooling capacity even at extreme high reject temperatures has to be provided. Meeting all this requirements within one cooler design is technically not feasible. Therefore, different coolers designs like integral rotary, split rotary or split linear are being employed. The use of flexure bearings supporting the driving mechanism has generated a new sub-group for the linear coolers; also, the coolers may either use a motor with moving magnet or with moving coil. AIM has mainly focussed on long life linear cooler technology and therefore developed a series of moving magnet flexure bearing compressors which meets MTTF's exceeding 20,000h (up to 50,000h with a Pulse-Tube coldfinger). These compressors have a full flexure bearing support on both sides of the driving mechanism. Cooler designs are being compared in regard to characteristic figures as described above.

A meta-analysis of in-vehicle and nomadic voice-recognition system interaction and driving performance.

PubMed

Simmons, Sarah M; Caird, Jeff K; Steel, Piers

2017-09-01

Driver distraction is a growing and pervasive issue that requires multiple solutions. Voice-recognition (V-R) systems may decrease the visual-manual (V-M) demands of a wide range of in-vehicle system and smartphone interactions. However, the degree that V-R systems integrated into vehicles or available in mobile phone applications affect driver distraction is incompletely understood. A comprehensive meta-analysis of experimental studies was conducted to address this knowledge gap. To meet study inclusion criteria, drivers had to interact with a V-R system while driving and doing everyday V-R tasks such as dialing, initiating a call, texting, emailing, destination entry or music selection. Coded dependent variables included detection, reaction time, lateral position, speed and headway. Comparisons of V-R systems with baseline driving and/or a V-M condition were also coded. Of 817 identified citations, 43 studies involving 2000 drivers and 183 effect sizes (r) were analyzed in the meta-analysis. Compared to baseline, driving while interacting with a V-R system is associated with increases in reaction time and lane positioning, and decreases in detection. When V-M systems were compared to V-R systems, drivers had slightly better performance with the latter system on reaction time, lane positioning and headway. Although V-R systems have some driving performance advantages over V-M systems, they have a distraction cost relative to driving without any system at all. The pattern of results indicates that V-R systems impose moderate distraction costs on driving. In addition, drivers minimally engage in compensatory performance adjustments such as reducing speed and increasing headway while using V-R systems. Implications of the results for theory, design guidelines and future research are discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

An Adaptive Method for Switching between Pedestrian/Car Indoor Positioning Algorithms based on Multilayer Time Sequences

PubMed Central

Gu, Zhining; Guo, Wei; Li, Chaoyang; Zhu, Xinyan; Guo, Tao

2018-01-01

Pedestrian dead reckoning (PDR) positioning algorithms can be used to obtain a target’s location only for movement with step features and not for driving, for which the trilateral Bluetooth indoor positioning method can be used. In this study, to obtain the precise locations of different states (pedestrian/car) using the corresponding positioning algorithms, we propose an adaptive method for switching between the PDR and car indoor positioning algorithms based on multilayer time sequences (MTSs). MTSs, which consider the behavior context, comprise two main aspects: filtering of noisy data in small-scale time sequences and using a state chain to reduce the time delay of algorithm switching in large-scale time sequences. The proposed method can be expected to realize the recognition of stationary, walking, driving, or other states; switch to the correct indoor positioning algorithm; and improve the accuracy of localization compared to using a single positioning algorithm. Our experiments show that the recognition of static, walking, driving, and other states improves by 5.5%, 45.47%, 26.23%, and 21% on average, respectively, compared with convolutional neural network (CNN) method. The time delay decreases by approximately 0.5–8.5 s for the transition between states and by approximately 24 s for the entire process. PMID:29495503

Parallel robot for micro assembly with integrated innovative optical 3D-sensor

NASA Astrophysics Data System (ADS)

Hesselbach, Juergen; Ispas, Diana; Pokar, Gero; Soetebier, Sven; Tutsch, Rainer

2002-10-01

Recent advances in the fields of MEMS and MOEMS often require precise assembly of very small parts with an accuracy of a few microns. In order to meet this demand, a new approach using a robot based on parallel mechanisms in combination with a novel 3D-vision system has been chosen. The planar parallel robot structure with 2 DOF provides a high resolution in the XY-plane. It carries two additional serial axes for linear and rotational movement in/about z direction. In order to achieve high precision as well as good dynamic capabilities, the drive concept for the parallel (main) axes incorporates air bearings in combination with a linear electric servo motors. High accuracy position feedback is provided by optical encoders with a resolution of 0.1 μm. To allow for visualization and visual control of assembly processes, a camera module fits into the hollow tool head. It consists of a miniature CCD camera and a light source. In addition a modular gripper support is integrated into the tool head. To increase the accuracy a control loop based on an optoelectronic sensor will be implemented. As a result of an in-depth analysis of different approaches a photogrammetric system using one single camera and special beam-splitting optics was chosen. A pattern of elliptical marks is applied to the surfaces of workpiece and gripper. Using a model-based recognition algorithm the image processing software identifies the gripper and the workpiece and determines their relative position. A deviation vector is calculated and fed into the robot control to guide the gripper.

Ecological drivers of guanaco recruitment: variable carrying capacity and density dependence.

PubMed

Marino, Andrea; Pascual, Miguel; Baldi, Ricardo

2014-08-01

Ungulates living in predator-free reserves offer the opportunity to study the influence of food limitation on population dynamics without the potentially confounding effects of top-down regulation or livestock competition. We assessed the influence of relative forage availability and population density on guanaco recruitment in two predator-free reserves in eastern Patagonia, with contrasting scenarios of population density. We also explored the relative contribution of the observed recruitment to population growth using a deterministic linear model to test the assumption that the studied populations were closed units. The observed densities increased twice as fast as our theoretical populations, indicating that marked immigration has taken place during the recovery phase experienced by both populations, thus we rejected the closed-population assumption. Regarding the factors driving variation in recruitment, in the low- to medium-density setting, we found a positive linear relationship between recruitment and surrogates of annual primary production, whereas no density dependence was detected. In contrast, in the high-density scenario, both annual primary production and population density showed marked effects, indicating a positive relationship between recruitment and per capita food availability above a food-limitation threshold. Our results support the idea that environmental carrying capacity fluctuates in response to climatic variation, and that these fluctuations have relevant consequences for herbivore dynamics, such as amplifying density dependence in drier years. We conclude that including the coupling between environmental variability in resources and density dependence is crucial to model ungulate population dynamics; to overlook temporal changes in carrying capacity may even mask density dependence as well as other important processes.

SU-F-T-84: Measurement and Monte-Carlo Simulation of Electron Phase Spaces Using a Wide Angle Magnetic Electron Spectrometer

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

Englbrecht, F; Lindner, F; Bin, J

2016-06-15

Purpose: To measure and simulate well-defined electron spectra using a linear accelerator and a permanent-magnetic wide-angle spectrometer to test the performance of a novel reconstruction algorithm for retrieval of unknown electron-sources, in view of application to diagnostics of laser-driven particle acceleration. Methods: Six electron energies (6, 9, 12, 15, 18 and 21 MeV, 40cm × 40cm field-size) delivered by a Siemens Oncor linear accelerator were recorded using a permanent-magnetic wide-angle electron spectrometer (150mT) with a one dimensional slit (0.2mm × 5cm). Two dimensional maps representing beam-energy and entrance-position along the slit were measured using different scintillating screens, read by anmore » online CMOS detector of high resolution (0.048mm × 0.048mm pixels) and large field of view (5cm × 10cm). Measured energy-slit position maps were compared to forward FLUKA simulations of electron transport through the spectrometer, starting from IAEA phase-spaces of the accelerator. The latter ones were validated against measured depth-dose and lateral profiles in water. Agreement of forward simulation and measurement was quantified in terms of position and shape of the signal distribution on the detector. Results: Measured depth-dose distributions and lateral profiles in the water phantom showed good agreement with forward simulations of IAEA phase-spaces, thus supporting usage of this simulation source in the study. Measured energy-slit position maps and those obtained by forward Monte-Carlo simulations showed satisfactory agreement in shape and position. Conclusion: Well-defined electron beams of known energy and shape will provide an ideal scenario to study the performance of a novel reconstruction algorithm using measured and simulated signal. Future work will increase the stability and convergence of the reconstruction-algorithm for unknown electron sources, towards final application to the electrons which drive the interaction of TW-class laser pulses with nanometer thin target foils to accelerate protons and ions to multi-MeV kinetic energy. Cluster of Excellence of the German Research Foundation (DFG) “Munich-Centre for Advanced Photonics”.« less

Opioids in oral fluid of Spanish drivers.

PubMed

Herrera-Gómez, Francisco; García-Mingo, Mercedes; Colás, Mónica; González-Luque, Juan Carlos; Álvarez, F Javier

2018-06-01

Driving under the influence of certain drugs is not allowed, and roadside drug testing is being considered an important tool for deterring driving under the influence of them. This study aimed to assess the presence and concentration of opioids, as well as their combined use with other drugs (laboratory confirmation after the on-road screening) in Spanish drivers between 2011 and 2016. In Spain, mandatory roadside breath alcohol and oral fluid drug testing (screening) are carried out by the Traffic Police using Dräger Alcotest ® 6810 device, and Dräger DrugTest ® 5000, DrugWipe ® , or Alere™ DDS ® 2 Mobile Test System. For positive cases in the period covered, 65,244, confirmation analysis and quantification using chromatographic techniques were performed. Opioids were confirmed in 8.6% of positive cases, being 7.2% positives to 6-acetylmorphine (6-AM), 6.5% to morphine, 5.4% to codeine, and 4.1% to methadone. The majority of the confirmed tests for morphine (96.5%), codeine (88.4%) and methadone (81.9) were also positive for 6-AM. The presence of other drugs, particularly cocaine and cannabis, was very common. Concentration values reached important levels. Positive results for morphine (0.1%), codeine (0.6%) or methadone (0.4%) alone were very infrequent. Drivers with a confirmed positive roadside test for morphine, codeine, and methadone had also consumed heroin and/or other illicit drugs, such as cocaine and/or THC, and at relevant concentrations. Improving interventions to combat the problem of driving under the influence of driving-impairing substances is a priority. Copyright © 2018 Elsevier B.V. All rights reserved.

Direct drive wind turbine

DOEpatents

Bywaters, Garrett Lee; Danforth, William; Bevington, Christopher; Stowell, Jesse; Costin, Daniel

2006-09-19

A wind turbine is provided that minimizes the size of the drive train and nacelle while maintaining the power electronics and transformer at the top of the tower. The turbine includes a direct drive generator having an integrated disk brake positioned radially inside the stator while minimizing the potential for contamination. The turbine further includes a means for mounting a transformer below the nacelle within the tower.

Direct drive wind turbine

DOEpatents

Bywaters, Garrett; Danforth, William; Bevington, Christopher; Jesse, Stowell; Costin, Daniel

2006-10-10

A wind turbine is provided that minimizes the size of the drive train and nacelle while maintaining the power electronics and transformer at the top of the tower. The turbine includes a direct drive generator having an integrated disk brake positioned radially inside the stator while minimizing the potential for contamination. The turbine further includes a means for mounting a transformer below the nacelle within the tower.

Direct drive wind turbine

DOEpatents

Bywaters, Garrett; Danforth, William; Bevington, Christopher; Stowell, Jesse; Costin, Daniel

2006-07-11

A wind turbine is provided that minimizes the size of the drive train and nacelle while maintaining the power electronics and transformer at the top of the tower. The turbine includes a direct drive generator having an integrated disk brake positioned radially inside the stator while minimizing the potential for contamination. The turbine further includes a means for mounting a transformer below the nacelle within the tower.

Direct drive wind turbine

DOEpatents

Bywaters, Garrett; Danforth, William; Bevington, Christopher; Jesse, Stowell; Costin, Daniel

2007-02-27

A wind turbine is provided that minimizes the size of the drive train and nacelle while maintaining the power electronics and transformer at the top of the tower. The turbine includes a direct drive generator having an integrated disk brake positioned radially inside the stator while minimizing the potential for contamination. The turbine further includes a means for mounting a transformer below the nacelle within the tower.

Drive for thinness, affect regulation and physical activity in eating disorders: a daily life study.

PubMed

Vansteelandt, Kristof; Rijmen, Frank; Pieters, Guido; Probst, Michel; Vanderlinden, Johan

2007-08-01

Using Ecological Momentary Assessment, the within patient associations between drive for thinness, emotional states, momentary urge to be physically active and physical activity were studied in 32 inpatients with an eating disorder. Participants received an electronic device and had to indicate at nine random times a day during 1 week their momentary drive for thinness, positive and negative emotional states and their urge to be physically active and physical activity. Multilevel analyses indicated that patients with higher mean levels for urge to be physically active were characterized by lower body mass index (BMI) and chronically negative affect whereas patients with higher mean levels for physical activity were characterized by lower BMI and higher dispositions for drive for thinness. In addition, within patient relations between drive for thinness and urge to be physically active were moderated by BMI and chronically negative affect whereas within patient relations between drive for thinness and physical activity were moderated by BMI. Finally, also positive emotional states were significantly associated with physical activity within patients. By using a daily process design, characteristics of physical activity were revealed that have not been identified with assessment methods that have a lower time resolution.

The Shock and Vibration Bulletin: Proceedings on the Symposium on ShocK and Vibration (52nd) Held in New Orleans, Louisiana on 26-28 October 1981. Part 3. Environmental Testing and Simulation, Flight Environments.

DTIC Science & Technology

1982-05-01

signal generation history can then be generated. These opera- processes generally consisted of recording tions work quite well electromagnetic ex...fninduerointe gualinicharactestics I PLOTTER MULTI CHANNEL TAPE RECORDER TEST ITEM 71T RESPONSE MOTIO ANALOG SIGNAL SHOCK CONDITIONING SPECTRUM ANALYZER...of TM to the EM. The exciter displacement producing a drive signal with excessive actua- drive signal is generated fron the linear sm tor stroke

Electromechanical latch

DOEpatents

Buerger, Stephen; Marron, Lisa C.; Martinez, Michael A.; Spletzer, Barry Louis

2016-12-13

An electromechanical latch is described herein. The electromechanical latch is a dual-actuator latch, wherein a first actuator and a second actuator are driven with precise timing to move a first latch part relative to a second latch part, and vice versa. When the electromechanical latch is in a closed position, the first rotary latch part is positioned to prevent rotation of the second rotary latch part in a first direction. To transition the electromechanical latch from the closed position to an open position, the first actuator drives the first rotary latch part such that the second rotary latch part is able to rotate in the first direction. Thereafter, the second actuator drives the second rotary latch part in the first direction until the electromechanical latch is in the open position.

Drinking and driving in the United States: comparing results from the 2007 and 1996 National Roadside Surveys.

PubMed

Kelley-Baker, Tara; Lacey, John H; Voas, Robert B; Romano, Eduardo; Yao, Jie; Berning, Amy

2013-01-01

The objectives of this study were to (a) use data from the 2007 National Roadside Survey (NRS) to determine the characteristics of weekend nighttime drivers with positive blood alcohol concentrations (BACs) on U.S. roads in 2007; (b) determine the relationship of the driving environment and trip characteristics associated with drinking drivers; and (c) compare the findings for the 2007 NRS with those for the 1996 NRS. Like the 1996 NRS, the 2007 NRS used a stratified random national roadside survey sample of the contiguous 48 states and collected nighttime data on Fridays and Saturdays between 10 p.m. and 3 a.m. Officers directed 8384 drivers into off-road parking areas where our research team asked them to participate in the survey. Of those approached, 7159 (85.4%) provided a breath test. Results revealed that 12 percent of the nighttime drivers had positive BACs, and of those, 2 percent were higher than the 0.08 BAC illegal limit in the United States. Since the 1996 NRS, we found significant reductions in the percentage of BAC-positive drivers across different demographic groups. Age was among the most significant factors associated with a weekend driver having a positive BAC. The probability that a driver would be drinking peaked in the 21- to 25-year-old age group. Male drivers were more likely than female drivers to be drinking, and Asian and Hispanic drivers were less likely than white drivers to be drinking. Drinking drivers were more likely to be driving short distances (5 or fewer miles) late at night (between 1 and 3 a.m.) and to be coming from a bar or restaurant. Finally, 26 percent of the drivers who reported that they would drive less than 5 miles on the night of the survey had positive BACs, compared to only 16 percent who indicated that they would drive between 6 and 20 miles and 10 percent who planned to drive more than 20 miles. The 2007 NRS provides another benchmark in the 4-decade record of drinking drivers on American roads and provides a basis for measuring progress in combating driving under the influence during the coming decade.

Lane-Level Vehicle Positioning : Integrating Diverse Systems for Precision and Reliability

DOT National Transportation Integrated Search

2013-05-13

Integrated global positioning system/inertial navigation system (GPS/INS) technology, the backbone of vehicle positioning systems, cannot provide the precision and reliability needed for vehicle-based, lane-level positioning in all driving environmen...