A mechanism for the dynamo terms to sustain closed-flux current, including helicity balance, by driving current which crosses the magnetic field

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

Jarboe, T. R.; Nelson, B. A.; Sutherland, D. A.

2015-07-15

An analysis of imposed dynamo current drive (IDCD) [T.R. Jarboe et al., Nucl. Fusion 52 083017 (2012)] reveals: (a) current drive on closed flux surfaces seems possible without relaxation, reconnection, or other flux-surface-breaking large events; (b) the scale size of the key physics may be smaller than is often computationally resolved; (c) helicity can be sustained across closed flux; and (d) IDCD current drive is parallel to the current which crosses the magnetic field to produce the current driving force. In addition to agreeing with spheromak data, IDCD agrees with selected tokamak data.

LETTER: Investigation of the effect of Alfven resonance mode conversion on fast wave current drive in ITER

NASA Astrophysics Data System (ADS)

Alava, M. J.; Heikkinen, J. A.; Hellsten, T.

1995-07-01

In order to reduce or to avoid ion cyclotron damping, the use of frequencies below the ion cyclotron frequency of minority ion species or the second harmonic of majority ion species has been proposed for fast wave current drive based on direct electron absorption. For these scenarios, the Alfven or ion-ion hybrid resonance can appear on the high field side of a tokamak. The presence of these resonances causes parasitic absorption, competing with the electron Landau damping and transit time magnetic pumping responsible for the fast wave current drive. In the present study, neglecting effects from toroidicity, the mode conversion at the Alfven resonance is shown to be of the order of 5 to 10% in the current drive scenarios for the planned ITER experiment. If the single pass absorption in the centre can be made sufficiently high, the conversion at the Alfven resonance becomes negligible

Investigation of the effect of Alfven resonance absorption on fast wave current drive in ITER

NASA Astrophysics Data System (ADS)

Alava, M. J.; Heikkinen, J. A.; Hellsten, T.

The use of frequencies below the ion cyclotron frequency of minority ion species or second harmonic of majority species has been proposed for fast wave current drive in order to reduce or to avoid ion cyclotron damping. For these scenarios, the Alfven resonance can appear on the high field side of a tokamak. The presence of this resonance causes parasitic absorption competing with the electron Landau damping and transit time magnetic pumping responsible for the fast wave current drive. In the present study, the mode conversion at the Alfven resonance is shown to be of the order of 5 to 10 percent in the current drive scenarios for the planned International Thermonuclear Experimental Reactor (ITER) experiment. However, if the single pass absorption in the center can be made sufficiently high, the conversion at the Alfven resonance becomes negligible.

An Exploratory Investigation: Are Driving Simulators Appropriate to Teach Pre-Driving Skills to Young Adults with Intellectual Disabilities?

ERIC Educational Resources Information Center

Brooks, Johnell O.; Mossey, Mary E.; Tyler, Peg; Collins, James C.

2014-01-01

Research examining driver training for young adults with intellectual disabilities has been limited since the 1970s. The current pilot and exploratory study investigated teaching pre-driving skills (i.e. lane keeping and speed maintenance) to young adults with intellectual disabilities using an interactive driving simulator to provide dynamic and…

A State-by-State Analysis of Laws Dealing With Driving Under the Influence of Drugs

DOT National Transportation Integrated Search

2009-12-01

This study reviewed each State statute regarding drug-impaired driving as of December 2008. There : is a high degree of variability across the States in the ways they approach drug-impaired driving. : Current laws in many States contain provisions ma...

Using AORSA to simulate helicon waves in DIII-D

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

Lau, C., E-mail: lauch@ornl.gov; Blazevski, D.; Green, D. L.

2015-12-10

Recent efforts have shown that helicon waves (fast waves at > 20ω{sub ci}) may be an attractive option for driving efficient off-axis current drive during non-inductive tokamak operation for DIII-D, ITER and DEMO. For DIII-D scenarios, the ray tracing code, GENRAY, has been extensively used to study helicon current drive efficiency and location as a function of many plasma parameters. The full wave code, AORSA, which is applicable to arbitrary Larmor radius and can resolve arbitrary ion cyclotron harmonic order, has been recently used to validate the ray tracing technique at these high cyclotron harmonics. If the SOL is ignored,more » it will be shown that the GENRAY and AORSA calculated current drive profiles are comparable for the envisioned high beta advanced scenarios for DIII-D, where there is high single pass absorption due to electron Landau damping and minimal ion damping. AORSA is also been used to estimate possible SOL effects on helicon current drive coupling and SOL absorption due to collisional and slow wave effects.« less

Using AORSA to simulate helicon waves in DIII-D

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

Lau, Cornwall H; Jaeger, E. F.; Bertelli, Nicola

2015-01-01

Recent efforts have shown that helicon waves (fast waves at >20 omega(ci)) may be an attractive option for driving efficient off-axis current drive during non-inductive tokamak operation for DIII-D, ITER and DEMO. For DIII-D scenarios, the ray tracing code, GENRAY, has been extensively used to study helicon current drive efficiency and location as a function of many plasma parameters. The full wave code, AORSA, which is applicable to arbitrary Larmor radius and can resolve arbitrary ion cyclotron harmonic order, has been recently used to validate the ray tracing technique at these high cyclotron harmonics. If the SOL is ignored, itmore » will be shown that the GENRAY and AORSA calculated current drive profiles are comparable for the envisioned high beta advanced scenarios for DIII-D, where there is high single pass absorption due to electron Landau damping and minimal ion damping. AORSA is also been used to estimate possible SOL effects on helicon current drive coupling and SOL absorption due to collisional and slow wave effects.« less

Experiment to investigate current drive by fast Alfven waves in a small tokamak

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

Gahl, J.; Ishihara, O.; Wong, K.

1985-07-01

An experiment has been carried out to study current generation by Doppler shifted cyclotron resonance heating of minority ions with a unidirectional wave in the small tokamak at Texas Tech University. One of the objectives of the experiment is to understand in detail the wave-particle interactions through which fast (compressional) Alfven waves in the ion cyclotron range of frequencies drive currents in toroidal devices.

Effectiveness evaluation of simulative workshops for newly licensed drivers.

PubMed

Rosenbloom, Tova; Eldror, Ehud

2014-02-01

The current study set to examine the effects of simulator use in driving instruction on newly licensed drivers, comparing the road safety knowledge and reported intended behavior, as well as the actual driving performance of new drivers. Participants consisted of 280 newly licensed driver, of which 140 whose drivers license training included additional simulator-based lessons, and 140 drivers whose training precluded simulator-based lessons. All drivers answered questionnaires pertaining to their intended safe driving behaviors (according to Ajzen's (2000) theory of planned behavior), and to their traffic safety knowledge. Of the initial sample, 40 drivers received actual driving performance evaluation by an expert driving instructor, as well as by in-vehicle data recorders (IVDRs). We assumed that safer drivers report safer driving intentions, demonstrate greater traffic safety knowledge, evaluated as safer drivers by the driving instructor, and display lower and stable driving parameters on the IVDRs. We hypothesized that theoretical driving studies combined with practical training on simulators will elevate the safety level of novices driving. Hierarchical regression analyses on driving intentions indicated that drivers who did not receive simulator-based lessons demonstrated safer driving intentions compared to drivers who received simulator-based lessons. This pattern possibly indicating the drivers who received simulator-based lessons felt more confident in their driving abilities compared to drivers who did not receive simulated training. No significant difference was found in traffic safety knowledge, or in the evaluation of the expert driving instructor. IDVR data comparisons indicated drivers who received simulator-based lessons braked more often and were less prone to headway events, suggesting a more responsive driving style. These findings do not point to any significant advantage or disadvantage of the current simulator-based driving training over other driving training methods. Copyright © 2013 Elsevier Ltd. All rights reserved.

Heating and current drive on NSTX

NASA Astrophysics Data System (ADS)

Wilson, J. R.; Batchelor, D.; Carter, M.; Hosea, J.; Ignat, D.; LeBlanc, B.; Majeski, R.; Ono, M.; Phillips, C. K.; Rogers, J. H.; Schilling, G.

1997-04-01

Low aspect ratio tokamaks pose interesting new challenges for heating and current drive. The NSTX (National Spherical Tokamak Experiment) device to be built at Princeton is a low aspect ratio toroidal device that has the achievement of high toroidal beta (˜45%) and non-inductive operation as two of its main research goals. To achieve these goals significant auxiliary heating and current drive systems are required. Present plans include ECH (Electron cyclotron heating) for pre-ionization and start-up assist, HHFW (high harmonic fast wave) for heating and current drive and eventually NBI (neutral beam injection) for heating, current drive and plasma rotation.

Cell phone use while driving in North Carolina : 2002 update report

DOT National Transportation Integrated Search

2002-12-01

As a follow-on to an earlier study funded by the North Carolina Governor's Highway Safety Program, the current study was carried out to further understanding regarding the safety implications of cellular telephone use while driving. The study involve...

Impact of gender, organized athletics, and video gaming on driving skills in novice drivers

PubMed Central

Miller, Gregory A.

2018-01-01

Given that novice drivers tend to be young, and teenagers and young adult drivers are involved in the greatest number of accidents, it is important that we understand what factors impact the driving skills of this population of drivers. The primary aim of the present study was to understand the impact of gender, organized athletics, and video gaming on driving skills of novice drivers under real-world driving conditions. Novice driving students having less than five hours driving experience previous to a normal driving lesson were evaluated on their self-confidence (self-reported) prior to the lesson and driving skill evaluated by their instructor during the course of the lesson. Information was collected about gender, age, whether or not the students were involved in organized athletics, and the extent of their video game playing. There was no impact of gender or extent of video game playing on driving skills. Females were significantly less self-confident with driving than males, but this did not translate to gender differences in driving skills. Being involved in organized athletics—either currently or in the past—significantly enhanced driving skills in both females and males. Finally, novice drivers’ age was negatively correlated with driving skills. That is, younger novice drivers (especially males) had better driving skills than older novice drivers. This is counter to popular belief that young drivers lack technical driving skills because they have less experience behind the wheel. Based on the results of the current study, we hypothesize that the relatively high accident rate of younger drivers (especially male drivers) is most likely due to inattention to safety considerations rather than lack of technical driving ability. PMID:29364957

Impact of gender, organized athletics, and video gaming on driving skills in novice drivers.

PubMed

Wayne, Nancy L; Miller, Gregory A

2018-01-01

Given that novice drivers tend to be young, and teenagers and young adult drivers are involved in the greatest number of accidents, it is important that we understand what factors impact the driving skills of this population of drivers. The primary aim of the present study was to understand the impact of gender, organized athletics, and video gaming on driving skills of novice drivers under real-world driving conditions. Novice driving students having less than five hours driving experience previous to a normal driving lesson were evaluated on their self-confidence (self-reported) prior to the lesson and driving skill evaluated by their instructor during the course of the lesson. Information was collected about gender, age, whether or not the students were involved in organized athletics, and the extent of their video game playing. There was no impact of gender or extent of video game playing on driving skills. Females were significantly less self-confident with driving than males, but this did not translate to gender differences in driving skills. Being involved in organized athletics-either currently or in the past-significantly enhanced driving skills in both females and males. Finally, novice drivers' age was negatively correlated with driving skills. That is, younger novice drivers (especially males) had better driving skills than older novice drivers. This is counter to popular belief that young drivers lack technical driving skills because they have less experience behind the wheel. Based on the results of the current study, we hypothesize that the relatively high accident rate of younger drivers (especially male drivers) is most likely due to inattention to safety considerations rather than lack of technical driving ability.

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.

A Prospective Study of Loss of Consciousness in Epilepsy Using Virtual Reality Driving Simulation and Other Video Games

PubMed Central

Yang, Li; Morland, Thomas B.; Schmits, Kristen; Rawson, Elizabeth; Narasimhan, Poojitha; Motelow, Joshua E.; Purcaro, Michael J.; Peng, Kathy; Raouf, Saned; DeSalvo, Matthew N.; Oh, Taemin; Wilkerson, Jerome; Bod, Jessica; Srinivasan, Aditya; Kurashvili, Pimen; Anaya, Joseph; Manza, Peter; Danielson, Nathan; Ransom, Christopher B.; Huh, Linda; Elrich, Susan; Padin-Rosado, Jose; Naidu, Yamini; Detyniecki, Kamil; Hamid, Hamada; Fattahi, Pooia; Astur, Robert; Xiao, Bo; Duckrow, Robert B.; Blumenfeld, Hal

2010-01-01

Patients with epilepsy are at risk of traffic accidents when they have seizures while driving. However, driving is an essential part of normal daily life in many communities, and depriving patients of driving privileges can have profound consequences for their economic and social well being. In the current study, we collected ictal performance data from a driving simulator and two other video games in patients undergoing continuous video/EEG monitoring. We captured 22 seizures in 13 patients and found that driving impairment during seizures differed both in terms of magnitude and character, depending on the seizure type. Our study documents the feasibility of the prospective study of driving and other behaviors during seizures through the use of computer-based tasks. This methodology may be applied to further describe differential driving impairment in specific types of seizures and to gain data on anatomical networks disrupted in seizures that impair consciousness and driving safety. PMID:20537593

The choice to text and drive in younger drivers: behavior may shape attitude.

PubMed

Atchley, Paul; Atwood, Stephanie; Boulton, Aaron

2011-01-01

Following a previous study that reported a large number of young adult drivers text and drive, the current study investigated this behavior by looking at patterns of use and driver assessment of the risk of the behavior. The data from the current study converge with and extended the previous work showing 70% of the 348 young adult drivers surveyed report initiating texts while driving while higher numbers reply to texts (81%) and read texts (92%) while driving. Additional drivers also report doing these behaviors, but only while stopped in traffic, showing only 2% never text and drive under any circumstances. The drivers indicated that they perceived these behaviors to be very risky and riskier than talking on a cell phone while driving, but perception of risk was a very weak predictor of behavior (for initiating texts) or had no effect on texting (for replying or reading texts while driving). In addition, a factor analysis of the perception of road conditions while texting revealed that making the choice to engage in texting (initiating) led drivers to perceive road conditions as being safer than if they replied to a text or read a text, suggesting that choosing to engage in the behavior itself changes attitudes toward risk. Copyright © 2010 Elsevier Ltd. All rights reserved.

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

Harvey, R. W.

This DOE grant supported fusion energy research, a potential long-term solution to the world's energy needs. Magnetic fusion, exemplified by confinement of very hot ionized gases, i.e., plasmas, in donut-shaped tokamak vessels is a leading approach for this energy source. Thus far, a mixture of hydrogen isotopes has produced 10's of megawatts of fusion power for seconds in a tokamak reactor at Princeton Plasma Physics Laboratory in New Jersey. The research grant under consideration, ER54684, uses computer models to aid in understanding and projecting efficacy of heating and current drive sources in the National Spherical Torus Experiment, a tokamak variant,more » at PPPL. The NSTX experiment explores the physics of very tight aspect ratio, almost spherical tokamaks, aiming at producing steady-state fusion plasmas. The current drive is an integral part of the steady-state concept, maintaining the magnetic geometry in the steady-state tokamak. CompX further developed and applied models for radiofrequency (rf) heating and current drive for applications to NSTX. These models build on a 30 year development of rf ray tracing (the all-frequencies GENRAY code) and higher dimensional Fokker-Planck rf-collisional modeling (the 3D collisional-quasilinear CQL3D code) at CompX. Two mainline current-drive rf modes are proposed for injection into NSTX: (1) electron Bernstein wave (EBW), and (2) high harmonic fast wave (HHFW) modes. Both these current drive systems provide a means for the rf to access the especially high density plasma--termed high beta plasma--compared to the strength of the required magnetic fields. The CompX studies entailed detailed modeling of the EBW to calculate the efficiency of the current drive system, and to determine its range of flexibility for driving current at spatial locations in the plasma cross-section. The ray tracing showed penetration into NSTX bulk plasma, relatively efficient current drive, but a limited ability to produce current over the whole radial plasma cross-section. The actual EBW experiment will cost several million dollars, and remains in the proposal stage. The HHFW current drive system has been experimentally implemented on NSTX, and successfully drives substantial current. The understanding of the experiment is to be accomplished in terms of general concepts of rf current drive, and also detailed modeling of the experiment which can discern the various competing processes which necessarily occur simultaneously in the experiment. An early discovery of the CompX codes, GENRAY and CQL3D, was that there could be significant interference between the neutral beam injection fast ions in the machine (injected for plasma heating) and the HHFW energy. Under many NSTX experimental conditions, power which could go to the fast ions would then be unavailable for current drive by the desired HHFW interaction with electrons. This result has been born out by experiments; the modeling helps in understanding difficulties with HHFW current drive, and has enabled adjustment of the experiment to avoid interaction with neutral beam injected fast ions thereby achieving stronger HHFW current drive. The detailed physics modeling of the various competing processes is almost always required in fusion energy plasma physics, to ensure a reasonably accurate and certain interpretation of the experiment, enabling the confident design of future, more advanced experiments and ultimately a commercial fusion reactor. More recent work entails detailed investigation of the interaction of the HHFW radiation for fast ions, accounting for the particularly large radius orbits in NSTX, and correlations between multiple HHFW-ion interactions. The spherical aspect of the NSTX experiment emphasized particular physics such as the large orbits which are present to some degree in all tokamaks, but gives clearer clues on the resulting physics phenomena since competing physics effects are reduced.« less

Bipedal vs. unipedal: a comparison between one-foot and two-foot driving in a driving simulator.

PubMed

Wang, Dong-Yuan Debbie; Richard, F Dan; Cino, Cullen R; Blount, Trevin; Schmuller, Joseph

2017-04-01

Is it better to drive with one foot or with two feet? Although two-foot driving has fostered interminable debate in the media, no scientific and systematic research has assessed this issue and federal and local state governments have provided no answers. The current study compared traditional unipedal (one-foot driving, using the right foot to control the accelerator and the brake pedal) with bipedal (two-foot driving, using the right foot to control the accelerator and the left foot to control the brake pedal) responses to a visual stimulus in a driving simulator study. Each of 30 undergraduate participants drove in a simulated driving scenario. They responded to a STOP sign displayed on the centre of the screen by bringing their vehicle to a complete stop. Brake RT was shorter under the bipedal condition, while throttle RT showed advantage under the unipedal condition. Stopping time and distance showed a bipedal advantage, however. We discuss further limitations of the current study and implications in a driving task. Before drawing any conclusions from the simulator study, further on-road driving tests are necessary to confirm these obtained bipedal advantages. Practitioner Summary: Traditional unipedal (using the right foot to control the accelerator and the brake pedal) with bipedal (using the right foot to control the accelerator and the left foot to control the brake pedal) responses to a visual stimulus in a driving simulator were compared. Our results showed a bipedal advantage. Promotion: Although two-foot driving has fostered interminable debate in the media, no scientific and systematic research has assessed this issue and federal and local state governments have provided no answers. Traditional (one-foot driving, using the right foot to control the accelerator and the brake pedal) with bipedal (using the right foot to control the accelerator and the left foot to control the brake pedal) responses to a visual stimulus in a simulated driving study were compared. Throttle reaction time was faster in the unipedal condition whereas brake reaction time, stopping time and stopping distance showed a bipedal advantage. We discuss further theoretical issues and implications in a driving task.

Effect of simulator training on fitness-to-drive after stroke: a 5-year follow-up of a randomized controlled trial.

PubMed

Devos, Hannes; Akinwuntan, Abiodun Emmanuel; Nieuwboer, Alice; Ringoot, Isabelle; Van Berghen, Karen; Tant, Mark; Kiekens, Carlotte; De Weerdt, Willy

2010-01-01

No long-term studies have been reported on the effect of training programs on driving after stroke. The authors' primary aim was to determine the effect of simulator versus cognitive rehabilitation therapy on fitness-to-drive at 5 years poststroke. A second aim was to investigate differences in clinical characteristics between stroke survivors who resumed and stopped driving. In a previously reported randomized controlled trial, 83 stroke survivors received 15 hours of simulator training (n = 42) or cognitive therapy (n = 41). In this 5-year follow-up study, 61 participants were reassessed. Fitness-to-drive decisions were obtained from medical, visual, neuropsychological, and on-road tests; 44 participants (simulator group, n = 21; cognitive group, n = 23) completed all assessments. The primary outcome measures were fitness-to-drive decision and current driving status. The authors found that 5 years after stroke, 18 of 30 participants (60%) in the simulator group were considered fit to drive, compared with 15 of 31 (48%) in the cognitive group (P = .36); 34 of 61 (56%) participants were driving. Current drivers were younger (P = .04), had higher Barthel scores (P = .008), had less comorbidity (P = .01), and were less severely depressed (P = .02) than those who gave up driving. The advantage of simulator-based driving training over cognitive rehabilitation therapy, evident at 6 months poststroke, had faded 5 years later. Poststroke drivers were younger and less severely affected and depressed than nondrivers.

An Imposed Dynamo Current Drive Experiment: Demonstration of Confinement

NASA Astrophysics Data System (ADS)

Jarboe, Thomas; Hansen, Chris; Hossack, Aaron; Marklin, George; Morgan, Kyle; Nelson, Brian; Sutherland, Derek; Victor, Brian

2014-10-01

An experiment for studying and developing the efficient sustainment of a spheromak with sufficient confinement (current-drive power heats the plasma to its stability β-limit) and in the keV temperature range is discussed. A high- β spheromak sustained by imposed dynamo current drive (IDCD) is justified because: previous transient experiments showed sufficient confinement in the keV range with no external toroidal field coil; recent results on HIT-SI show sustainment with sufficient confinement at low temperature; the potential of IDCD of solving other fusion issues; a very attractive reactor concept; and the general need for efficient current drive in magnetic fusion. The design of a 0.55 m minor radius machine with the required density control, wall loading, and neutral shielding for a 2 s pulse is presented. Peak temperatures of 1 keV and toroidal currents of 1.35 MA and 16% wall-normalized plasma beta are envisioned. The experiment is large enough to address the key issues yet small enough for rapid modification and for extended MHD modeling of startup and code validation.

Plasma response to sustainment with imposed-dynamo current drive in HIT-SI and HIT-SI3

NASA Astrophysics Data System (ADS)

Hossack, A. C.; Jarboe, T. R.; Chandra, R. N.; Morgan, K. D.; Sutherland, D. A.; Penna, J. M.; Everson, C. J.; Nelson, B. A.

2017-07-01

The helicity injected torus—steady inductive (HIT-SI) program studies efficient, steady-state current drive for magnetic confinement plasmas using a novel experimental method. Stable, high-beta spheromaks have been sustained using steady, inductive current drive. Externally induced loop voltage and magnetic flux are oscillated together so that helicity and power injection are always positive, sustaining the edge plasma current indefinitely. Imposed-dynamo current drive (IDCD) theory further shows that the entire plasma current is sustained. The method is ideal for low aspect ratio, toroidal geometries with closed flux surfaces. Experimental studies of spheromak plasmas sustained with IDCD have shown stable magnetic profiles with evidence of pressure confinement. New measurements show coherent motion of a stable spheromak in response to the imposed perturbations. On the original device two helicity injectors were mounted on either side of the spheromak and the injected mode spectrum was predominantly n  =  1. Coherent, rigid motion indicates that the spheromak is stable and a lack of plasma-generated n  =  1 energy indicates that the maximum q is maintained below 1 during sustainment. Results from the HIT-SI3 device are also presented. Three inductive helicity injectors are mounted on one side of the spheromak flux conserver. Varying the relative injector phasing changes the injected mode spectrum which includes n  =  2, 3, and higher modes.

Parents' and peers' contribution to risky driving of male teen drivers.

PubMed

Taubman - Ben-Ari, Orit; Kaplan, Sigal; Lotan, Tsippy; Prato, Carlo Giacomo

2015-05-01

The current study joins efforts devoted to understanding the associations of parents' personality, attitude, and behavior, and to evaluating the added contribution of peers to the driving behavior of young drivers during their solo driving. The study combines data gathered using in-vehicle data recorders from actual driving of parents and their male teen driver with data collected from self-report questionnaires completed by the young drivers. The sample consists of 121 families, who participated in the study for 12 months, beginning with the licensure of the teen driver. The current examination concentrates on the last 3 months of this first year of driving. The experimental design was based on a random control assignment into three treatment groups (with different forms of feedback) and a control group (with no feedback). Findings indicate that the parents' (especially the fathers') sensation seeking, anxiety, and aggression, as well as their risky driving events rate were positively associated with higher risky driving of the young driver. In addition, parents' involvement in the intervention, either by feedback or by training, led to lower risky driving events rate of young drivers compared to the control group. Finally, higher cohesion and adaptability mitigated parents' model for risky driving, and peers norms' of risky driving were associated with higher risk by the teen drivers. We conclude by claiming that there is an unequivocal need to look at a full and complex set of antecedents in parents' personality, attitudes, and behavior, together with the contribution of peers to the young drivers' reckless driving, and address the practical implications for road safety. Copyright © 2015 Elsevier Ltd. All rights reserved.

Impact of New Regulations On Assessing Driving Status (INROADS): a South Australian seizure clinic cohort.

PubMed

Hafner, Jessica; Horn, Sharon; Robinson, Martin; Purdie, Grant; Jannes, Jim

2014-11-01

The ability to drive is important to patients and driving restriction often leads to restriction of employment and social opportunities. In March 2012, Austroads released revised Assessing Fitness to Drive Guidelines (AFTDG) with significant changes for drivers with seizures and epilepsy. Our study aimed to assess the impact of the 2012 AFTDG on a Seizure Clinic cohort compared to the previous 2003 AFTDG and an individual's current driving status. We also aimed to quantify the difference in AFTDG interpretation between expert and non-expert doctors. We performed a retrospective observational audit of case notes for all patients managed in a public hospital outpatient Seizure Clinic between 1 March 2010 and 1 March 2012. A total of 142 patients were included in the analysis. Comparison between the 2003 and 2012 AFTDG resulted in reduced eligibility to drive a private vehicle by 2.1% (52.5% versus 50.4%) and commercial vehicle by 2.2% (4.5% versus 2.3%). The proportion of those currently driving against guideline recommendations increased (private 8.8% versus 19%; commercial 50% versus 100%) and the non-expert assessor was more likely to agree with the experts with the 2012 AFTDG. In summary, the 2012 AFTDG has had a measurable impact on driving eligibility in individuals with seizure although it is easier to interpret for non-expert doctors. Greater awareness of the 2012 AFTDG is required to reduce the proportion of patients driving against current recommendations. Copyright © 2014 Elsevier Ltd. All rights reserved.

Safe driving practices and factors associated with motor-vehicle collisions among people with insulin-treated diabetes mellitus: Results from the Diabetes and Driving (DAD) study.

PubMed

Almigbal, Turky H; Alfaifi, Abdullah A; Aleid, Muath A; Billah, Baki; Alramadan, Mohammed J; Sheshah, Eman; AlMogbel, Turki A; Aldekhayel, Ghassan A; Batais, Mohammed Ali

2018-06-01

The aim of this study was to assess the prevalence of people with insulin-treated diabetes mellitus (ITDM) who have discussed issues related to diabetes and driving with their health care providers (HCPs). We also sought to determine the safe driving practices that are currently employed by this group. Finally, we investigated the factors that might increase the risk of motor-vehicle collisions (MVCs) among this group in Saudi Arabia. This cross-sectional study surveyed a representative sample of 429 current male drivers with ITDM using a structured questionnaire in Saudi Arabia. Most of the participants (76.5%) never discussed topics regarding diabetes and driving with their HCPs. The majority of the participants (61.8%) reported at least never doing one of the following: (a) carrying a blood glucose testing kit while driving, (b) testing their blood glucose level before driving or during a journey, or (c) having thought of a specific threshold of blood glucose level that would preclude driving. Three factors were associated with a higher risk of MVCs among participants with ITDM: (a) being on a basal/boluses regimen, (b) never having a discussion regarding diabetes and driving with their HCPs, and (c) having experienced hypoglycemia during driving. The majority of people with ITDM had not had a discussion regarding diabetes and driving with their HCPs, which was reflected by a lack of safe driving practices. People with ITDM should be encouraged to take precautions while driving in order to prevent future MVCs. This research highlights the importance of investing more effort in educating drivers who have diabetes about safe driving practices by their health care providers. Also, it will attracts the attention of policymakers for an urgent need to establish clear policies and procedures for dealing with drivers who have diabetes. Copyright © 2018 National Safety Council and Elsevier Ltd. All rights reserved.

Driving Behaviour Profile of Drivers with Autism Spectrum Disorder (ASD).

PubMed

Chee, Derserri Y; Lee, Hoe C; Patomella, Ann-Helen; Falkmer, Torbjörn

2017-09-01

The symptomatology of autism spectrum disorder (ASD) can make driving risky, but little is known about the on-road driving behaviour of individuals with ASD. This study assessed and compared the on-road driving performance of drivers with and without ASD, and explored how the symptomatology of ASD hinders or facilitates on-road driving performance. Sixteen drivers with ASD and 21 typically-developed drivers participated in the study. Drivers with ASD underperformed in vehicle manoeuvring, especially at left-turns, right-turns and pedestrian crossings. However, drivers with ASD outperformed the TD group in aspects related to rule-following such as using the indicator at roundabouts and checking for cross-traffic when approaching intersections. Drivers with ASD in the current study presented with a range of capabilities and weaknesses during driving.

Attentional Differences in a Driving Hazard Perception Task in Adults with Autism Spectrum Disorders

ERIC Educational Resources Information Center

Sheppard, Elizabeth; van Loon, Editha; Underwood, Geoffrey; Ropar, Danielle

2017-01-01

The current study explored attentional processing of social and non-social stimuli in ASD within the context of a driving hazard perception task. Participants watched videos of road scenes and detected hazards while their eye movements were recorded. Although individuals with ASD demonstrated relatively good detection of driving hazards, they were…

Experiments Using Local Helicity Injectors in the Lower Divertor Region as the Majority Current Drive in a Tokamak Plasma

NASA Astrophysics Data System (ADS)

Perry, Justin M.

Local helicity injection (LHI) is a non-solenoidal current drive capable of achieving high-Ip tokamak startup with a relatively compact and non-invasive array of current injectors in the plasma scrape-off layer. The choice of injector location within the edge region is flexible, but has a profound influence on the nature of the current drive in LHI discharges. Past experiments on the Pegasus ST with injection on the low-field-side near the outboard midplane produced plasmas dominated by inductive drive resulting primarily from plasma geometry evolution over the discharge. Recent experiments with injection on the high-field- side in the lower divertor region produce plasmas dominated by helicity injection current drive, with relatively static plasma geometry, and thus negligible inductive drive. Plasma current up to 200 kA is driven with helicity injection as the dominant current drive using a pair of 4 cm2 area injectors sourcing 8 kA of total injected current. Steady sustainment with LHI current drive alone is demonstrated, with 100 kA sustained for 18 ms. Maximum achievable plasma current is found to scale approximately linearly with a plasma-geometry- normalized form of the effective loop voltage from LHI, Vnorm = AinjVinj/Rinj, where A inj is the total injector area, Vinj is the injector bias voltage, and Rinj is the major radius of the injectors. A newly-discovered MHD regime for LHI-driven plasmas is described, in which the large-amplitude n = 1 fluctuations at 20-50 kHz which are generally dominant during LHI are abruptly reduced by an order of magnitude on the outboard side. High frequency fluctuations ( f > 400 kHz) increase inside the plasma edge at the same time. This regime results in improved plasma current and pervasive changes to plasma behavior, and may suggest short wavelength turbulence as a current drive mechanism during LHI.

On current drive by Ohkawa mechanism of electron cyclotron wave in large inverse aspect ratio tokamaks

NASA Astrophysics Data System (ADS)

Zheng, Pingwei; Gong, Xueyu; Lu, Xingqiang; He, Lihua; Cao, Jingjia; Huang, Qianhong; Deng, Sheng

2018-03-01

A localized and efficient current drive method in the outer-half region of the tokamak with a large inverse aspect ratio is proposed via the Ohkawa mechanism of electron cyclotron (EC) waves. Further off-axis Ohkawa current drive (OKCD) via EC waves was investigated in high electron beta β e HL-2M-like tokamaks with a large inverse aspect ratio, and in EAST-like tokamaks with a low inverse aspect ratio. OKCD can be driven efficiently, and the driven current profile is spatially localized in the radial region, ranging from 0.62 to 0.85, where the large fraction of trapped electrons provides an excellent advantage for OKCD. Furthermore, the current drive efficiency increases with an increase in minor radius, and then drops when the minor radius beyond a certain value. The effect of trapped electrons greatly enhances the current driving capability of the OKCD mechanism. The highest current drive efficiency can reach 0.183 by adjusting the steering mirror to change the toroidal and poloidal incident angle, and the total driven current by OKCD can reach 20-32 kA MW-1 in HL-2M-like tokamaks. The current drive is less efficient for the EAST-like scenario due to the lower inverse aspect ratio. The results show that OKCD may be a valuable alternative current drive method in large inverse aspect ratio tokamaks, and the potential capabilities of OKCD can be used to suppress some important magnetohydrodynamics instabilities in the far off-axis region.

Stabilizing effect of helical current drive on tearing modes

NASA Astrophysics Data System (ADS)

Yuan, Y.; Lu, X. Q.; Dong, J. Q.; Gong, X. Y.; Zhang, R. B.

2018-01-01

The effect of helical driven current on the m = 2/n = 1 tearing mode is studied numerically in a cylindrical geometry using the method of reduced magneto-hydro-dynamic simulation. The results show that the local persistent helical current drive from the beginning time can be applied to control the tearing modes, and will cause a rebound effect called flip instability when the driven current reaches a certain value. The current intensity threshold value for the occurrence of flip instability is about 0.00087I0. The method of controlling the development of tearing mode with comparative economy is given. If the local helical driven current is discontinuous, the magnetic island can be controlled within a certain range, and then, the tearing modes stop growing; thus, the flip instability can be avoided. We also find that the flip instability will become impatient with delay injection of the driven current because the high order harmonics have been developed in the original O-point. The tearing mode instability can be controlled by using the electron cyclotron current drive to reduce the gradient of the current intensity on the rational surfaces.

Current Drive

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

Faulconer, D.W

2004-03-15

Certain devices aimed at magnetic confinement of thermonuclear plasma rely on the steady flow of an electric current in the plasma. In view of the dominant place it occupies in both the world magnetic-confinement fusion effort and the author's own activity, the tokamak toroidal configuration is selected as prototype for discussing the question of how such a current can be maintained. Tokamaks require a stationary toroidal plasma current, this being traditionally provided by a pulsed magnetic induction which drives the plasma ring as the secondary of a transformer. Since this mechanism is essentially transient, and steady-state fusion reactor operation hasmore » manifold advantages, significant effort is now devoted to developing alternate steady-state means of generating toroidal current. These methods are classed under the global heading of 'noninductive current drive' or simply 'current drive', generally, though not exclusively, employing the injection of waves and/or toroidally directed particle beams. In what follows we highlight the physical mechanisms underlying surprisingly various approaches to driving current in a tokamak, downplaying a number of practical and technical issues. When a significant data base exists for a given method, its experimental current drive efficiency and future prospects are detailed.« less

Is the useful field of view a good predictor of at-fault crash risk in elderly Japanese drivers?

PubMed

Sakai, Hiroyuki; Uchiyama, Yuji; Takahara, Miwa; Doi, Shun'ichi; Kubota, Fumiko; Yoshimura, Takayoshi; Tachibana, Atsumichi; Kurahashi, Tetsuo

2015-05-01

Although age-related decline in the useful field of view (UFOV) is well recognized as a risk factor for at-fault crash involvement in elderly drivers, there is still room to study its applicability to elderly Japanese drivers. In the current study, we thus examined the relationship between UFOV and at-fault crash history in an elderly Japanese population. We also explored whether potential factors that create awareness of reduced driving fitness could be a trigger for the self-regulation of driving in elderly drivers. We measured UFOV and at-fault crash history from 151 community-dwelling Japanese aged 60 years or older, and compared UFOV of at-fault crash-free and crash-involved drivers. We also measured self-evaluated driving style using a questionnaire. UFOV in crash-involved drivers was significantly lower than that in crash-free drivers. No significant difference was found in self-evaluated driving style between crash-free and crash-involved drivers. In addition, there was no significant association between UFOV and self-evaluated driving style. The present study showed that UFOV is a good predictor of at-fault crash risk in elderly Japanese drivers. Furthermore, our data imply that it might be difficult for elderly drivers to adopt appropriate driving strategies commensurate with their current driving competence. © 2014 Japan Geriatrics Society.

Ten Years down the Road: Predictors of Driving Cessation

ERIC Educational Resources Information Center

Edwards, Jerri D.; Bart, Edward; O'Connor, Melissa L.; Cissell, Gayla

2010-01-01

Purpose: Recent prospective studies have found that cognition is a more salient predictor of driving cessation than physical performance or demographic factors among community-dwelling older adults. However, these studies have been limited to 5 years of follow-up. The current study used data from the Maryland Older Drivers Project to examine…

Novel CRISPR/Cas9 gene drive constructs reveal insights into mechanisms of resistance allele formation and drive efficiency in genetically diverse populations

PubMed Central

Liu, Chen

2017-01-01

A functioning gene drive system could fundamentally change our strategies for the control of vector-borne diseases by facilitating rapid dissemination of transgenes that prevent pathogen transmission or reduce vector capacity. CRISPR/Cas9 gene drive promises such a mechanism, which works by converting cells that are heterozygous for the drive construct into homozygotes, thereby enabling super-Mendelian inheritance. Although CRISPR gene drive activity has already been demonstrated, a key obstacle for current systems is their propensity to generate resistance alleles, which cannot be converted to drive alleles. In this study, we developed two CRISPR gene drive constructs based on the nanos and vasa promoters that allowed us to illuminate the different mechanisms by which resistance alleles are formed in the model organism Drosophila melanogaster. We observed resistance allele formation at high rates both prior to fertilization in the germline and post-fertilization in the embryo due to maternally deposited Cas9. Assessment of drive activity in genetically diverse backgrounds further revealed substantial differences in conversion efficiency and resistance rates. Our results demonstrate that the evolution of resistance will likely impose a severe limitation to the effectiveness of current CRISPR gene drive approaches, especially when applied to diverse natural populations. PMID:28727785

Overview of ECRH experimental results

NASA Astrophysics Data System (ADS)

Lloyd, Brian

1998-08-01

A review of the present status of electron cyclotron heating and current drive experiments in toroidal fusion devices is presented. In addition to basic heating and current drive studies the review also addresses advances in wave physics and the application of electron cyclotron waves for instability control, transport studies, pre-ionization/start-up assist, etc. A comprehensive overview is given with particular emphasis on recent advances since the major review of Erckmann and Gasparino (1994) ( 36 1869), including results from the latest generation of high-power, high-frequency experiments.

Current drive by helicon waves

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

Paul, Manash Kumar; Bora, Dhiraj; ITER Organization, Cadarache Centre-building 519, 131008 St. Paul-Lez-Durance

2009-01-01

Helicity in the dynamo field components of helicon wave is examined during the novel study of wave induced helicity current drive. Strong poloidal asymmetry in the wave magnetic field components is observed during helicon discharges formed in a toroidal vacuum chamber of small aspect ratio. High frequency regime is chosen to increase the phase velocity of helicon waves which in turn minimizes the resonant wave-particle interactions and enhances the contribution of the nonresonant current drive mechanisms. Owing to the strong poloidal asymmetry in the wave magnetic field structures, plasma current is driven mostly by the dynamo-electric-field, which arise due tomore » the wave helicity injection by helicon waves. Small, yet finite contribution from the suppressed wave-particle resonance cannot be ruled out in the operational regime examined. A brief discussion on the parametric dependence of plasma current along with numerical estimations of nonresonant components is presented. A close agreement between the numerical estimation and measured plasma current magnitude is obtained during the present investigation.« less

Factors associated with driving in teens with autism spectrum disorders.

PubMed

Huang, Patty; Kao, Trudy; Curry, Allison E; Durbin, Dennis R

2012-01-01

To compare the characteristics of driving and nondriving teens and explore the driving outcomes for teens with higher functioning autism spectrum disorders. Parents of teens aged 15 to 18 years with a parent-reported diagnosis of an autism spectrum disorder enrolled in Interactive Autism Network, an online research registry, were eligible for this cross-sectional study. An online survey was used for data collection. A total of 297 parents completed the survey. Sixty-three percent of teens currently drive or plan to drive. Twenty-nine percent of the teens who are age-eligible to drive currently drive. Compared with age-eligible but nondriving teens, a greater proportion of driving teens were in full-time regular education (p < .005), planned to attend college (p < .001), and held a paid job (p = .008). A greater proportion of parents of driving teens had taught ≥1 teen to drive previously (p < .001). There were no differences in gender, autism subtype, attention deficit/hyperactivity disorder diagnosis, parental age or education, or access to public transportation. Driving predictors included individualized education plans with driving goals, indicators of functional status (classroom placement, college aspiration, and job experience), and parent experience with teaching teens to drive. Twelve percent of teens received driving citations, and 12% of teens had been involved in a motor vehicle crash. Although a significant proportion of teens with higher functioning autism spectrum disorders were driving or learning to drive, the fact that most driving teens' individualized education plans did not include driving goals suggests an area of opportunity for improvement in transition planning. Driving teens were more frequently in regular education settings with college aspirations, which could help schools identify potential drivers.

Electrical motor/generator drive apparatus and method

DOEpatents

Su, Gui Jia

2013-02-12

The present disclosure includes electrical motor/generator drive systems and methods that significantly reduce inverter direct-current (DC) bus ripple currents and thus the volume and cost of a capacitor. The drive methodology is based on a segmented drive system that does not add switches or passive components but involves reconfiguring inverter switches and motor stator winding connections in a way that allows the formation of multiple, independent drive units and the use of simple alternated switching and optimized Pulse Width Modulation (PWM) schemes to eliminate or significantly reduce the capacitor ripple current.

Optimized calculation of the synergy conditions between electron cyclotron current drive and lower hybrid current drive on EAST

NASA Astrophysics Data System (ADS)

Wei, Wei; Bo-Jiang, Ding; Y, Peysson; J, Decker; Miao-Hui, Li; Xin-Jun, Zhang; Xiao-Jie, Wang; Lei, Zhang

2016-01-01

The optimized synergy conditions between electron cyclotron current drive (ECCD) and lower hybrid current drive (LHCD) with normal parameters of the EAST tokamak are studied by using the C3PO/LUKE code based on the understanding of the synergy mechanisms so as to obtain a higher synergistic current and provide theoretical reference for the synergistic effect in the EAST experiment. The dependences of the synergistic effect on the parameters of two waves (lower hybrid wave (LHW) and electron cyclotron wave (ECW)), including the radial position of the power deposition, the power value of the LH and EC waves, and the parallel refractive indices of the LHW (N∥) are presented and discussed. Project supported by the National Magnetic Confinement Fusion Science Program of China (Grant Nos. 2011GB102000, 2012GB103000, and 2013GB106001), the National Natural Science Foundation of China (Grant Nos. 11175206 and 11305211), the JSPS-NRF-NSFC A3 Foresight Program in the Field of Plasma Physics (Grant No. 11261140328), and the Fundamental Research Funds for the Central Universities of China (Grant No. JZ2015HGBZ0472).

The relationship of dangerous driving with traffic offenses: A study on an adapted measure of dangerous driving.

PubMed

Iliescu, Dragoş; Sârbescu, Paul

2013-03-01

Using data from three different samples and more than 1000 participants, the current study examines differences in dangerous driving in terms of age, gender, professional driving, as well as the relationship of dangerous driving with behavioral indicators (mileage) and criteria (traffic offenses). The study uses an adapted (Romanian) version of the Dula Dangerous Driving Index (DDDI, Dula and Ballard, 2003) and also reports data on the psychometric characteristics of this measure. Findings suggest that the Romanian version of the DDDI has sound psychometric properties. Dangerous driving is higher in males and occasional drivers, is not correlated with mileage and is significantly related with speeding as a traffic offense, both self-reported and objectively measured. The utility of predictive models including dangerous driving is not very large: logistic regression models have a significant fit to the data, but their misclassification rate (especially in terms of sensitivity) is unacceptable high. Copyright © 2012 Elsevier Ltd. All rights reserved.

Isotopic effect in experiments on lower hybrid current drive in the FT-2 tokamak

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

Lashkul, S. I., E-mail: Serguey.lashkul@mail.ioffe.ru; Altukhov, A. B.; Gurchenko, A. D., E-mail: aleksey.gurchenko@mail.ioffe.ru

To analyze factors influencing the limiting value of the plasma density at which lower hybrid (LH) current drive terminates, the isotopic factor (the difference in the LH resonance densities in hydrogen and deuterium plasmas) was used for the first time in experiments carried out at the FT-2 tokamak. It is experimentally found that the efficiency of LH current drive in deuterium plasma is appreciably higher than that in hydrogen plasma. The significant role of the parametric decay of the LH pumping wave, which hampers the use of the LH range of RF waves for current drive at high plasma densities,more » is confirmed. It is demonstrated that the parameters characterizing LH current drive agree well with the earlier results obtained at large tokamaks.« less

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.

Helicopter Drive System on-Condition Maintenance Capability (UH-1/AH-1)

DTIC Science & Technology

1976-07-01

Capability 17 2.2 FACTORS LIMITING THE PERFORMANCE OF THE STUDY . . 18 2.3 ASSUMPTIONS USED IN THE ANALYSIS 20 2.3.1 Assembly Operability 20 2.3.2...DRIVE SYSTEM COMPONENTS AND THEIR EFFECTIVITY 64 2 AIRCRAFT TECHNICAL MANUALS USED DURING THE STUDY 66 3 DRIVE SYSTEM COMPONENTS DA2410 RECORDS...the federal stock number, and current effectivity of these assemblies. The general approach used was to examine the overhaul and acci- dent records

A Pilot Study Assessing Performance and Visual Attention of Teenagers with ASD in a Novel Adaptive Driving Simulator.

PubMed

Wade, Joshua; Weitlauf, Amy; Broderick, Neill; Swanson, Amy; Zhang, Lian; Bian, Dayi; Sarkar, Medha; Warren, Zachary; Sarkar, Nilanjan

2017-11-01

Individuals with Autism Spectrum Disorder (ASD), compared to typically-developed peers, may demonstrate behaviors that are counter to safe driving. The current work examines the use of a novel simulator in two separate studies. Study 1 demonstrates statistically significant performance differences between individuals with (N = 7) and without ASD (N = 7) with regards to the number of turning-related driving errors (p < 0.01). Study 2 shows that both the performance-based feedback group (N = 9) and combined performance- and gaze-sensitive feedback group (N = 8) achieved statistically significant reductions in driving errors following training (p < 0.05). These studies are the first to present results of fine-grained measures of visual attention of drivers and an adaptive driving intervention for individuals with ASD.

A Pilot Study Assessing Performance and Visual Attention of Teenagers with ASD in a Novel Adaptive Driving Simulator

ERIC Educational Resources Information Center

Wade, Joshua; Weitlauf, Amy; Broderick, Neill; Swanson, Amy; Zhang, Lian; Bian, Dayi; Sarkar, Medha; Warren, Zachary; Sarkar, Nilanjan

2017-01-01

Individuals with Autism Spectrum Disorder (ASD), compared to typically-developed peers, may demonstrate behaviors that are counter to safe driving. The current work examines the use of a novel simulator in two separate studies. Study 1 demonstrates statistically significant performance differences between individuals with (N = 7) and without ASD…

Focusing on appraisals: how and why anger and fear influence driving risk perception.

PubMed

Lu, Jingyi; Xie, Xiaofei; Zhang, Ruogu

2013-06-01

The present research explores how and why anger and fear influence driving risk perception. Based on appraisal tendency framework, researchers hypothesized that anger and fear would influence driving risk perception in opposite directions due to their differences in appraisals. Study 1 showed that anger reduced risk perception, whereas fear increased it. In Studies 2, 3, and 4, the researchers adopted the paradigm of reappraisal to investigate the causes of the opposite effects found in Study 1. Consistent with our hypothesis, appraisals accounted for these effects: After reappraisals along the dimensions of certainty (Study 2), control (Study 3), and responsibility (Study 4), the different effects between anger and fear on driving risk perception diminished or disappeared. In addition, fearful or angry experience mediated the effects of reappraisals on driving risk perception. The findings highlight the necessity to differentiate anger and fear in road safety management. Additionally, the current research also provides feasible methods (e.g., certainty, control, or responsibility reappraisal) to intervene in driving risk perception, which is important for driving safety. Copyright © 2013 National Safety Council and Elsevier Ltd. All rights reserved.

Cognitive deficits are associated with poorer simulated driving in older adults with heart failure

PubMed Central

2013-01-01

Background Cognitive impairment is prevalent in older adults with heart failure (HF) and associated with reduced functional independence. HF patients appear at risk for reduced driving ability, as past work in other medical samples has shown cognitive dysfunction to be an important contributor to driving performance. The current study examined whether cognitive dysfunction was independently associated with reduced driving simulation performance in a sample of HF patients. Methods 18 persons with HF (67.72; SD = 8.56 year) completed echocardiogram and a brief neuropsychological test battery assessing global cognitive function, attention/executive function, memory and motor function. All participants then completed the Kent Multidimensional Assessment Driving Simulation (K-MADS), a driving simulator scenario with good psychometric properties. Results The sample exhibited an average Mini Mental State Examination (MMSE) score of 27.83 (SD = 2.09). Independent sample t-tests showed that HF patients performed worse than healthy adults on the driving simulation scenario. Finally, partial correlations showed worse attention/executive and motor function were independently associated with poorer driving simulation performance across several indices reflective of driving ability (i.e., centerline crossings, number of collisions, % of time over the speed limit, among others). Conclusion The current findings showed that reduced cognitive function was associated with poor simulated driving performance in older adults with HF. If replicated using behind-the-wheel testing, HF patients may be at elevated risk for unsafe driving and routine driving evaluations in this population may be warranted. PMID:24499466

Sex Differences in the Effects of Marijuana on Simulated Driving Performance†

PubMed Central

Anderson, Beth M.; Rizzo, Matthew; Block, Robert I.; Pearlson, Godfrey D.; O'Leary, Daniel S.

2011-01-01

In the United States, one in six teenagers has driven under the influence of marijuana. Driving under the influence of marijuana and alcohol is equally prevalent, despite the fact that marijuana use is less common than alcohol use. Much of the research examining the effects of marijuana on driving performance was conducted in the 1970s and led to equivocal findings. During that time, few studies included women and driving simulators were rudimentary. Further, the potency of marijuana commonly used recreationally has increased. This study examined sex differences in the acute effects of marijuana on driving performance using a realistic, validated driving simulator. Eighty-five subjects (n = 50 males, 35 females) participated in this between-subjects, double-blind, placebo controlled study. In addition to an uneventful, baseline segment of driving, participants were challenged with collision avoidance and distracted driving scenarios. Under the influence of marijuana, participants decreased their speed and failed to show expected practice effects during a distracted drive. No differences were found during the baseline driving segment or collision avoidance scenarios. No differences attributable to sex were observed. This study enhances the current literature by identifying distracted driving and the integration of prior experience as particularly problematic under the influence of marijuana. PMID:20464803

Plasma heating and current drive using intense, pulsed microwaves

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

Cohen, B.I.; Cohen, R.H.; Nevins, W.M.

1988-01-01

The use of powerful new microwave sources, e.g., free-electron lasers and relativistic gyrotrons, provide unique opportunities for novel heating and current-drive schemes in the electron-cyclotron and lower-hybrid ranges of frequencies. These high-power, pulsed sources have a number of technical advantages over conventional, low-intensity sources; and their use can lead to improved current-drive efficiencies and better penetration into a reactor-grade plasma in specific cases. The Microwave Tokamak Experiment at Lawrence Livermore National Laboratory will provide a test for some of these new heating and current-drive schemes. This paper reports theoretical progress both in modeling absorption and current drive for intense pulsesmore » and in analyzing some of the possible complications that may arise, e.g., parametric instabilities and nonlinear self-focusing. 22 refs., 9 figs., 1 tab.« less

Are selective serotonin reuptake inhibitors safe for drivers? What is the evidence?

PubMed

Ravera, Silvia; Ramaekers, Johannes G; de Jong-van den Berg, Lolkje T W; de Gier, Johan J

2012-05-01

Selective serotonin reuptake inhibitors (SSRIs) are widely used medications to treat several psychiatric diseases and, above all, depression. They seem to be as effective as older antidepressants but have a different adverse effect profile. Despite their favorable safety profile, little is known about their influence on traffic safety. To conduct a literature review to summarize the current evidence on the role of SSRIs in traffic safety, particularly concerning undesirable effects that could potentially impair fitness to drive, experimental and pharmacoepidemiologic studies on driving impairment, 2 existing categorization systems for driving-impairing medications, and the European legislative procedures for assessing fitness to drive before issuing a driver's license and driving under the influence of medicines. The article search was performed in the following electronic databases: MEDLINE, PsycINFO, ScienceDirect, and SafetyLit. The English-language scientific literature was searched using key words such as SSRIs and psychomotor performance, car crash or traffic accident, and adverse effects. For inclusion in this review, papers had to be full-text articles, refer to possible driving-related adverse effects, and be experimental or pharmacoepidemiologic studies on SSRIs and traffic accident risks. No restrictions concerning publication year were applied. Ten articles were selected as background information on driving-related adverse effects, and 15 articles were selected regarding experimental and pharmacoepidemiologic work. Regarding SSRI adverse effects, the most reported undesirable effects referring to driving impairment were anxiety, agitation, sleep disturbances, headache, increased risk of suicidal behavior, and deliberate self-harm. Regarding the remaining issues addressed in this article, inconsistencies were found between the outcomes of the selected experimental and epidemiologic studies and between the 2 existing categorization systems under evaluation. Some pitfalls of the current legislative scenario were identified as well. Based on the current evidence, it was concluded that more experimental and epidemiologic research is needed to elucidate the relationship between SSRI use and traffic safety. Furthermore, a revision of the existing categorization systems and harmonized European legislation in the field of medication use and driving were highly recommended. Copyright © 2012 Elsevier HS Journals, Inc. All rights reserved.

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.

Modelling of minority ion cyclotron current drive during the activated phase of ITER

NASA Astrophysics Data System (ADS)

Laxåback, M.; Hellsten, T.

2005-12-01

Neoclassical tearing modes, triggered by the long-period sawteeth expected in tokamaks with large non-thermal α-particle populations, may impose a severe β limit on experiments with large fusion yields and on reactors. Sawtooth destabilization by localized current drive could relax the β limit and improve plasma performance. 3He minority ion cyclotron current drive around the sawtooth inversion radius has been planned for ITER. Several ion species, including beam injected D ions and fusion born α particles, are however also resonant in the plasma and may represent a parasitic absorption of RF power. Modelling of minority ion cyclotron current drive in an ITER-FEAT-like plasma is presented, including the effects of ion trapping, finite ion drift orbit widths, wave-induced radial transport and the coupled evolution of wave fields and resonant ion distributions. The parasitic absorption of RF power by the other resonant species is concluded to be relatively small, but the 3He minority current drive is nevertheless negligible due to the strong collisionality of the 3He ions and the drag current by toroidally counter-rotating background ions and co-rotating electrons. H minority current drive is found to be a significantly more effective alternative.

Oscillating field current drive experiments in the Madison Symmetric Torus

NASA Astrophysics Data System (ADS)

Blair, Arthur P., Jr.

Oscillating Field Current Drive (OFCD) is an inductive current drive method for toroidal pinches. To test OFCD, two 280 Hz 2 MVA oscillators were installed in the toroidal and poloidal magnetic field circuits of the Madison Symmetric Torus (MST) Reversed Field Pinch (RFP.) Partial sustainment experiments were conducted where the two voltage oscillations were superimposed on the standard MST power supplies. Supplementary current drive of about 10% has been demonstrated, comparable to theoretical predictions. However, maximum current drive does not coincide with maximum helicity injection rate - possibly due to an observed dependence of core and edge tearing modes on the relative phase of the oscillators. A dependence of wall interactions on phase was also observed, the largest interaction coinciding with negative current drive. Experiments were conducted at 280 and 530 Hz. 530 Hz proved to be too high and yielded little or no net current drive. Experiments at 280 Hz proved more fruitful. A 1D relaxed state model was used to predict the effects of voltage amplitudes, frequencies, and waveforms on performance and to optimize the design of OFCD hardware. Predicted current drive was comparable to experimental values, though the aforementioned phase dependence was not. Comparisons were also made with a more comprehensive 3D model which proved to be a more accurate predictor of current drive. Both 1D and 3D models predicted the feasability of full sustainment via OFCD. Experiments were also conducted with only the toroidal field oscillator applied. An entrainment of the natural sawtooth frequency to our applied oscillation was observed as well as a slow modulation of the edge tearing mode amplitudes. A large modulation (20 to 80 eV) of the ion temperature was also observed that can be partially accounted for by collisional heating via magnetic pumping. Work is in progress to increase the power of the existing OFCD hardware.

The dangers of rumination on the road: Predictors of risky driving.

PubMed

Suhr, Kyle A; Dula, Chris S

2017-02-01

Past studies found many different types of factors can influence dangerous driving behaviors. Driver inattention, such as driving under the influence or using a cell phone while driving, was found to contribute to risky driving behaviors. Rumination is a cognitive process that may also contribute to risky driving behaviors due to its influence on attention and limited executive processes. The present study explores the potential role of rumination in dangerous driving behavior endorsement. It was hypothesized that trait rumination would be significantly related to dangerous driving behaviors and that this relationship would be conditional to the sex of the participant. Six-hundred and fifty-three Southeastern university students were recruited to participate and asked to complete multiple questionnaires measuring anger rumination, thought content, driving anger, and dangerous driving behaviors. It was demonstrated that self-reported risky driving behaviors significantly predicted dangerous driving behavior endorsement on the Dula Dangerous Driving Index. Trait rumination scores were found to predict self-reported dangerous driving, aggressive driving, and risky driving behaviors as well as trait driving anger scores. However, no conditional effects based on the sex of the participant were found. It appeared males and females were equally likely to report dangerous driving behaviors, driving anger thoughts, and trait anger rumination. Findings from the current study may assist in understanding how cognitive processes influence different driving behaviors and help develop methods to re-direct attention to safe driving behaviors, and conversely away from ruminative thoughts that increase the likelihood of dangerous driving. Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

The Quality and Accuracy of Mobile Apps to Prevent Driving After Drinking Alcohol.

PubMed

Wilson, Hollie; Stoyanov, Stoyan R; Gandabhai, Shailen; Baldwin, Alexander

2016-08-08

Driving after the consumption of alcohol represents a significant problem globally. Individual prevention countermeasures such as personalized mobile app aimed at preventing such behavior are widespread, but there is little research on their accuracy and evidence base. There has been no known assessment investigating the quality of such apps. This study aimed to determine the quality and accuracy of apps for drink driving prevention by conducting a review and evaluation of relevant mobile apps. A systematic app search was conducted following PRISMA guidelines. App quality was assessed using the Mobile App Rating Scale (MARS). Apps providing blood alcohol calculators (hereafter "calculators") were reviewed against current alcohol advice for accuracy. A total of 58 apps (30 iOS and 28 Android) met inclusion criteria and were included in the final analysis. Drink driving prevention apps had significantly lower engagement and overall quality scores than alcohol management apps. Most calculators provided conservative blood alcohol content (BAC) time until sober calculations. None of the apps had been evaluated to determine their efficacy in changing either drinking or driving behaviors. This novel study demonstrates that most drink driving prevention apps are not engaging and lack accuracy. They could be improved by increasing engagement features, such as gamification. Further research should examine the context and motivations for using apps to prevent driving after drinking in at-risk populations. Development of drink driving prevention apps should incorporate evidence-based information and guidance, lacking in current apps.

The Quality and Accuracy of Mobile Apps to Prevent Driving After Drinking Alcohol

PubMed Central

Stoyanov, Stoyan R; Gandabhai, Shailen; Baldwin, Alexander

2016-01-01

Background Driving after the consumption of alcohol represents a significant problem globally. Individual prevention countermeasures such as personalized mobile apps aimed at preventing such behavior are widespread, but there is little research on their accuracy and evidence base. There has been no known assessment investigating the quality of such apps. Objective This study aimed to determine the quality and accuracy of apps for drink driving prevention by conducting a review and evaluation of relevant mobile apps. Methods A systematic app search was conducted following PRISMA guidelines. App quality was assessed using the Mobile App Rating Scale (MARS). Apps providing blood alcohol calculators (hereafter “calculators”) were reviewed against current alcohol advice for accuracy. Results A total of 58 apps (30 iOS and 28 Android) met inclusion criteria and were included in the final analysis. Drink driving prevention apps had significantly lower engagement and overall quality scores than alcohol management apps. Most calculators provided conservative blood alcohol content (BAC) time until sober calculations. None of the apps had been evaluated to determine their efficacy in changing either drinking or driving behaviors. Conclusions This novel study demonstrates that most drink driving prevention apps are not engaging and lack accuracy. They could be improved by increasing engagement features, such as gamification. Further research should examine the context and motivations for using apps to prevent driving after drinking in at-risk populations. Development of drink driving prevention apps should incorporate evidence-based information and guidance, lacking in current apps. PMID:27502956

Driving with Mild Cognitive Impairment or Dementia: Cognitive Test Performance and Proxy Report of Daily Life Function in Older Women.

PubMed

Vaughan, Leslie; Hogan, Patricia E; Rapp, Stephen R; Dugan, Elizabeth; Marottoli, Richard A; Snively, Beverly M; Shumaker, Sally A; Sink, Kaycee M

2015-09-01

To investigate associations between proxy report of cognitive and functional limitations and cognitive performance and current or former driving status in older women with mild cognitive impairment (MCI) and all-cause dementia. Cross-sectional data analysis of retrospectively identified older women with adjudicated MCI and all-cause dementia in the Women's Health Initiative Memory Study-Epidemiology of Cognitive Health Outcomes (WHIMS-ECHO). Academic medical center. Women (mean age ± standard deviation 83.7 ± 3.5) adjudicated with MCI or dementia during Year 1, 2, 3, or 4 of the WHIMS-ECHO follow-up period (N = 385). The telephone-administered cognitive battery included tests of attention, verbal learning and memory, verbal fluency, executive function, working memory, and global cognitive function plus self-report measures of depressive symptomatology. The Dementia Questionnaire (DQ) was administered to a knowledgeable proxy (family member, friend). Sixty percent of women with MCI and 40% of those with dementia are current drivers. Proxy reports of functional limitations in instrumental activities of daily living (IADLs) are associated with current driving status in women with MCI, whereas performance-based cognitive tests are not. In women with dementia, proxy reports of functional limitations in IADLs and performance-based cognitive tests are associated with current driving status, as expected. These findings have clinical implications for the importance of evaluating driving concurrently with other instrumental functional abilities in MCI and dementia. Additional work is needed to determine whether proxy report of cognitive and functional impairments should help guide referrals for driving assessment and rehabilitation or counseling for driving transition. © 2015, Copyright the Authors Journal compilation © 2015, The American Geriatrics Society.

Mild Cognitive Impairment and driving: Does in-vehicle distraction affect driving performance?

PubMed

Beratis, Ion N; Pavlou, Dimosthenis; Papadimitriou, Eleonora; Andronas, Nikolaos; Kontaxopoulou, Dionysia; Fragkiadaki, Stella; Yannis, George; Papageorgiou, Sokratis G

2017-06-01

In-vehicle distraction is considered to be an important cause of road accidents. Drivers with Mild Cognitive Impairment (MCI), because of their attenuated cognitive resources, may be vulnerable to the effects of distraction; however, previous relevant research is lacking. The main objective of the current study was to explore the effect of in-vehicle distraction on the driving performance of MCI patients, by assessing their reaction time at unexpected incidents and accident probability. Thirteen patients with MCI (age: 64.5±7.2) and 12 cognitively intact individuals (age: 60.0±7.7), all active drivers were introduced in the study. The driving simulator experiment included three distraction conditions: (a) undistracted driving, (b) conversing with passenger and (c) conversing through a hand-held mobile phone. The mixed ANOVA models revealed a greater effect of distraction on MCI patients. Specifically, the use of mobile phone induced a more pronounced impact on reaction time and accident probability in the group of patients, as compared to healthy controls. On the other hand, in the driving condition "conversing with passenger" the interaction effects regarding reaction time and accident probability were not significant. Notably, the aforementioned findings concerning the MCI patients in the case of the mobile phone were observed despite the effort of the drivers to apply a compensatory strategy by reducing significantly their speed in this driving condition. Overall, the current findings indicate, for the first time, that a common driving practice, such as the use of mobile phone, may have a detrimental impact on the driving performance of individuals with MCI. Copyright © 2017. Published by Elsevier Ltd.

A proof of principle spheromak experiment: The next step on a recently opened path to economical fusion power

NASA Astrophysics Data System (ADS)

Jarboe, Thomas; Marklin, George; Nelson, Brian; Sutherland, Derek; HIT Team Team

2013-10-01

A proof of principle experiment to study closed-flux energy confinement of a spheromak sustained by imposed dynamo current drive is described. A two-fluid validated NIMROD code has simulated closed-flux sustainment on a stable spheromak using imposed dynamo current drive (IDCD), demonstrating that dynamo current drive is compatible with closed flux. (submitted for publication and see adjacent poster.(spsap)) HIT-SI, a = 0.25 m, has achieved 90 kA of toroidal current, current gains of nearly 4, and operation from 5.5 kHz to 68 kHz, demonstrating the robustness of the method.(spsap) Finally, a reactor design study using fusion technology developed for ITER and modern nuclear technology shows a design that is economically superior to coal.(spsap) The spheromak reactor and development path are about a factor of 10 less expensive than that of the tokamak/stellarator. These exciting results justify a proof of principle (PoP) confinement experiment of a spheromak sustained by IDCD. Such an experiment (R = 1.5 m, a = 1 m, Itor = 3 . 2 MA, n = 4e19/m3, T = 3 keV) is described in detail.

The Effects of Dextromethorphan on Driving Performance and the Standardized Field Sobriety Test.

PubMed

Perry, Paul J; Fredriksen, Kristian; Chew, Stephanie; Ip, Eric J; Lopes, Ingrid; Doroudgar, Shadi; Thomas, Kelan

2015-09-01

Dextromethorphan (DXM) is abused most commonly among adolescents as a recreational drug to generate a dissociative experience. The objective of the study was to assess driving with and without DXM ingestion. The effects of one-time maximum daily doses of DXM 120 mg versus a guaifenesin 400 mg dose were compared among 40 healthy subjects using a crossover design. Subjects' ability to drive was assessed by their performance in a driving simulator (STISIM® Drive driving simulator software) and by conducting a standardized field sobriety test (SFST) administered 1-h postdrug administration. The one-time dose of DXM 120 mg did not demonstrate driving impairment on the STISIM® Drive driving simulator or increase SFST failures compared to guaifenesin 400 mg. Doses greater than the currently recommended maximum daily dose of 120 mg are necessary to perturb driving behavior. © 2015 American Academy of Forensic Sciences.

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

Open problems of magnetic island control by electron cyclotron current drive

DOE PAGES

Grasso, Daniela; Lazzaro, E.; Borgogno, D.; ...

2016-11-17

This study reviews key aspects of the problem of magnetic islands control by electron cyclotron current drive in fusion devices. On the basis of the ordering of the basic spatial and time scales of the magnetic reconnection physics, we present the established results, highlighting some of the open issues posed by the small-scale structures that typically accompany the nonlinear evolution of the magnetic islands and constrain the effect of the control action.

Arctic Ice-Ocean Coupling and Gyre Equilibration Observed With Remote Sensing

NASA Astrophysics Data System (ADS)

Dewey, Sarah; Morison, James; Kwok, Ronald; Dickinson, Suzanne; Morison, David; Andersen, Roger

2018-02-01

Model and observational evidence has shown that ocean current speeds in the Beaufort Gyre have increased and recently stabilized. Because these currents rival ice drift speeds, we examine the potential for the Beaufort Gyre's shift from a system in which the wind drives the ice and the ice drives a passive ocean to one in which the ocean often, in the absence of high winds, drives the ice. The resultant stress exerted on the ocean by the ice and the resultant Ekman pumping are reversed, without any change in average wind stress curl. Through these curl reversals, the ice-ocean stress provides a key feedback in Beaufort Gyre stabilization. This manuscript constitutes one of the first observational studies of ice-ocean stress inclusive of geostrophic ocean currents, by making use of recently available remote sensing data.

The cold driver: Cold stress while driving results in dangerous behavior.

PubMed

Morris, Drew M; Pilcher, June J

2016-10-01

Cool vehicle cabin temperatures can induce short-term non-hypothermic cold stress. The current study created a cold condition to examine the impact of cold stress on driving behavior. Forty-four participants drove a high-fidelity driving simulator during a thermal neutral or local torso cooled condition. Participants performed additional tasks to assess attention, psychomotor vigilance, and manual dexterity. Skin temperature was significantly lower in the cold condition while internal temperature was unaffected. Participants who had higher subjective ratings of cold followed lead vehicles closer and started to brake later. Participants in the cold condition followed the lead car 22% (0.82s) closer and started braking 20% (2.35s) later when approaching a stop sign during the car-following task. No change in attention, psychomotor vigilance, or dexterity was observed. The current results suggest that cold environmental conditions can contribute to dangerous driving behaviors. Measures of cold perception were also shown to predict changes in driving behavior. Copyright © 2016 Elsevier B.V. All rights reserved.

Improving driving advice provided to cardiology patients on discharge.

PubMed

Vusirikala, Amoolya; Backhouse, Mark; Schimansky, Sarah

2018-01-01

Certain cardiac conditions can limit patients' ability to drive. It remains the doctors' responsibility to advise patients of any driving restrictions and is particularly important after certain diagnoses or procedures. We identified that the quality of documented advice was variable and frequently no written driving advice was recorded on discharge. It was apparent that there was a lack of awareness and knowledge of the current Driving and Vehicle Licensing Agency (DVLA) guidance among junior doctors. We therefore designed a quality improvement project using Plan-Do-Study-Act (PDSA) methodology to improve the provision of driving advice on discharge from a cardiology ward by focusing on staff education. After collecting baseline data, we created a template with cardiology-specific DVLA advice. During the second PDSA cycle, we improved the electronic template and also introduced a hard copy on the ward. During the third PDSA cycle, we incorporated information on DVLA guidance in the specialty induction session. We also evaluated junior doctors' confidence of providing driving advice before and after this intervention. Baseline measurements showed that 10% (9/92) of all discharge summaries included driving advice. This improved to 49% (34/69) after the third PDSA cycle. Importantly, after receiving information on driving advice in the induction, junior doctors felt more confident in providing driving advice to cardiology patients on discharge. In conclusion, the provision of driving advice on discharge is an important element of patient safety. However, clinicians' knowledge and awareness of current DVLA guidance is often limited. We demonstrated a significant increase in the provision of driving advice by introducing a standardised template.

Study of the time-resolved, 3-dimensional current density distribution in solid metallic liners at 1 MA

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

Bott-Suzuki, S. C.; Cordaro, S. W.; Caballero Bendixsen, L. S.

We present a study of the time varying current density distribution in solid metallic liner experiments at the 1MA level. Measurements are taken using an array of magnetic field probes which provide 2D triangulation of the average centroid of the drive current in the load at 3 discrete axial positions. These data are correlated with gated optical self-emission imaging which directly images the breakdown and plasma formation region. Results show that the current density is azimuthally non-uniform, and changes significantly throughout the 100ns experimental timescale. Magnetic field probes show clearly motion of the current density around the liner azimuth overmore » 10ns timescales. If breakdown is initiated at one azimuthal location, the current density remains non-uniform even over large spatial extents throughout the current drive. The evolution timescales are suggestive of a resistive diffusion process or uneven current distributions among simultaneously formed but discrete plasma conduction paths.« less

Study of the time-resolved, 3-dimensional current density distribution in solid metallic liners at 1 MA

DOE PAGES

Bott-Suzuki, S. C.; Cordaro, S. W.; Caballero Bendixsen, L. S.; ...

2016-09-01

We present a study of the time varying current density distribution in solid metallic liner experiments at the 1MA level. Measurements are taken using an array of magnetic field probes which provide 2D triangulation of the average centroid of the drive current in the load at 3 discrete axial positions. These data are correlated with gated optical self-emission imaging which directly images the breakdown and plasma formation region. Results show that the current density is azimuthally non-uniform, and changes significantly throughout the 100ns experimental timescale. Magnetic field probes show clearly motion of the current density around the liner azimuth overmore » 10ns timescales. If breakdown is initiated at one azimuthal location, the current density remains non-uniform even over large spatial extents throughout the current drive. The evolution timescales are suggestive of a resistive diffusion process or uneven current distributions among simultaneously formed but discrete plasma conduction paths.« less

On the current drive capability of low dimensional semiconductors: 1D versus 2D

DOE PAGES

Zhu, Y.; Appenzeller, J.

2015-10-29

Low-dimensional electronic systems are at the heart of many scaling approaches currently pursuit for electronic applications. Here, we present a comparative study between an array of one-dimensional (1D) channels and its two-dimensional (2D) counterpart in terms of current drive capability. Lastly, our findings from analytical expressions derived in this article reveal that under certain conditions an array of 1D channels can outperform a 2D field-effect transistor because of the added degree of freedom to adjust the threshold voltage in an array of 1D devices.

The multidimensional driving style inventory a decade later: Review of the literature and re-evaluation of the scale.

PubMed

Taubman-Ben-Ari, Orit; Skvirsky, Vera

2016-08-01

The Multidimensional Driving Style Inventory (MDSI; Taubman - Ben-Ari, Mikulincer, & Gillath, 2004a), a self-report questionnaire assessing four broad driving styles, has been in use for the last ten years. During that time, numerous studies have explored the associations between the MDSI factors and sociodemographic and driving-related variables. The current paper employs two large data sets to summarize the accumulated knowledge, examining MDSI factors in samples of young drivers aged 17-21 (Study 1, n=1436) and older drivers aged 22-84 (Study 2, n=3409). Findings indicate that driving-related indicators are coherently and systematically related to the four driving styles in the expected directions, revalidating the structure of the MDSI. The results also help clarify the relationships between the driving styles and variables such as gender, ethnicity, car ownership, age, and experience, and suggest that driving styles are largely unaffected by sociodemographic characteristics, except for gender and ethnicity, and appear to represent a relatively stable and universal trait. The two studies highlight the validity and reliability of the MDSI, attesting to its practical value as a tool for purposes of research, evaluation, and intervention. Copyright © 2016 Elsevier Ltd. All rights reserved.

Driving evaluation methods for able-bodied persons and individuals with lower extremity disabilities: a review of assessment modalities

PubMed Central

Greve, Julia Maria D'Andréa; Santos, Luciana; Alonso, Angelica Castilho; Tate, Denise G

2015-01-01

Assessing the driving abilities of individuals with disabilities is often a very challenging task because each medical condition is accompanied by physical impairments and because relative individual functional performance may vary depending on personal characteristics. We identified existing driving evaluation modalities for able-bodied and lower extremity-impaired subjects (spinal cord injury patients and amputees) and evaluated the potential relationships between driving performance and the motor component of driving. An extensive scoping review of the literature was conducted to identify driving assessment tools that are currently used for able-bodied individuals and for those with spinal cord injury or lower extremity amputation. The literature search focused on the assessment of the motor component of driving. References were electronically obtained via Medline from the PubMed, Ovid, Web of Science and Google Scholar databases. This article compares the current assessments of driving performance for those with lower extremity impairments with the assessments used for able-bodied persons. Very few articles were found concerning “Lower Extremity Disabilities,” thus confirming the need for further studies that can provide evidence and guidance for such assessments in the future. Little is known about the motor component of driving and its association with the other driving domains, such as vision and cognition. The available research demonstrates the need for a more evidenced-based understanding of how to best evaluate persons with lower extremity impairment. PMID:26375567

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.

Numerical analysis on the synergy between electron cyclotron current drive and lower hybrid current drive in tokamak plasmas

NASA Astrophysics Data System (ADS)

Chen, S. Y.; Hong, B. B.; Liu, Y.; Lu, W.; Huang, J.; Tang, C. J.; Ding, X. T.; Zhang, X. J.; Hu, Y. J.

2012-11-01

The synergy between electron cyclotron current drive (ECCD) and lower hybrid current drive (LHCD) is investigated numerically with the parameters of the HL-2A tokamak. Based on the understanding of the synergy mechanisms, a high current driven efficiency or a desired radial current profile can be achieved through properly matching the parameters of ECCD and LHCD due to the flexibility of ECCD. Meanwhile, it is found that the total current driven by the electron cyclotron wave (ECW) and the lower hybrid wave (LHW) simultaneously can be smaller than the sum of the currents driven by the ECW and LHW separately, when the power of the ECW is much larger than the LHW power. One of the reasons leading to this phenomenon (referred to as negative synergy in this context) is that fast current-carrying electrons tend to be trapped, when the perpendicular velocity driven by the ECW is large and the parallel velocity decided by the LHW is correspondingly small.

Current challenges in autonomous driving

NASA Astrophysics Data System (ADS)

Barabás, I.; Todoruţ, A.; Cordoş, N.; Molea, A.

2017-10-01

Nowadays the automotive industry makes a quantum shift to a future, where the driver will have smaller and smaller role in driving his or her vehicle ending up being totally excluded. In this paper, we have investigated the different levels of driving automatization, the prospective effects of these new technologies on the environment and traffic safety, the importance of regulations and their current state, the moral aspects of introducing these technologies and the possible scenarios of deploying the autonomous vehicles. We have found that the self-driving technologies are facing many challenges: a) They must make decisions faster in very diverse conditions which can include many moral dilemmas as well; b) They have an important potential in reducing the environmental pollution by optimizing their routes, driving styles by communicating with other vehicles, infrastructures and their environment; c) There is a considerable gap between the self-drive technology level and the current regulations; fortunately, this gap shows a continuously decreasing trend; d) In case of many types of imminent accidents management there are many concerns about the ability of making the right decision. Considering that this field has an extraordinary speed of development, our study is up to date at the submission deadline. Self-driving technologies become increasingly sophisticated and technically accessible, and in some cases, they can be deployed for commercial vehicles as well. According to the current stage of research and development, it is still unclear how the self-driving technologies will be able to handle extreme and unexpected events including their moral aspects. Since most of the traffic accidents are caused by human error or omission, it is expected that the emergence of the autonomous technologies will reduce these accidents in their number and gravity, but the very few currently available test results have not been able to scientifically underpin this issue yet. The increasing trend in automation of vehicles will radically change the composition of car industry players, as mechatronics will not only be a complementary part of the automobile industry but an indispensable part of it. There is a reasonable expectation that automated cars will perform the same or better in all respects than their conventional counterparts. However, it seems that the current regulations do not keep up with the development of technology and sometimes hinder the development and testing of autonomous technologies.

The Impact of Adolescents' News and Action Movie Viewing on Risky Driving Behavior: A Longitudinal Study

ERIC Educational Resources Information Center

Beullens, Kathleen; Roe, Keith; Van den Bulck, Jan

2011-01-01

Traffic crashes remain an important cause of injury and death among young people. The aim of the current study was to examine whether adolescents' viewing of particular television genres predicted later risky driving. Data were collected with a two-wave panel survey (N = 426); structural equation modeling was used to examine the relationships…

[A literature review on epidemiologic research on sleep disturbances in the elderly].

PubMed

Doi, Yuriko

2015-06-01

One of the issues facing our super-aging society of Japan is to secure the elderly's safety and health. According to the latest 10-year statistics of the National Police Agency, the number of elderly driving deaths 75 years of age and over has risen 1.3 times from 2003 to 2013, whereas driving deaths decreased by less than half among the people under age 75 during the same period of time. This paper reviews the current literature on epidemiologic studies investigating the associations of sleep disturbances with adverse driving events and driving practice among elderly drivers. The results suggest a cognitive behavioral therapy for insomnia as a promising method for improving their driving capacity. Key words: elderly driving, epidemiology, sleep disturbances

Dynamics of the exponential integrate-and-fire model with slow currents and adaptation.

PubMed

Barranca, Victor J; Johnson, Daniel C; Moyher, Jennifer L; Sauppe, Joshua P; Shkarayev, Maxim S; Kovačič, Gregor; Cai, David

2014-08-01

In order to properly capture spike-frequency adaptation with a simplified point-neuron model, we study approximations of Hodgkin-Huxley (HH) models including slow currents by exponential integrate-and-fire (EIF) models that incorporate the same types of currents. We optimize the parameters of the EIF models under the external drive consisting of AMPA-type conductance pulses using the current-voltage curves and the van Rossum metric to best capture the subthreshold membrane potential, firing rate, and jump size of the slow current at the neuron's spike times. Our numerical simulations demonstrate that, in addition to these quantities, the approximate EIF-type models faithfully reproduce bifurcation properties of the HH neurons with slow currents, which include spike-frequency adaptation, phase-response curves, critical exponents at the transition between a finite and infinite number of spikes with increasing constant external drive, and bifurcation diagrams of interspike intervals in time-periodically forced models. Dynamics of networks of HH neurons with slow currents can also be approximated by corresponding EIF-type networks, with the approximation being at least statistically accurate over a broad range of Poisson rates of the external drive. For the form of external drive resembling realistic, AMPA-like synaptic conductance response to incoming action potentials, the EIF model affords great savings of computation time as compared with the corresponding HH-type model. Our work shows that the EIF model with additional slow currents is well suited for use in large-scale, point-neuron models in which spike-frequency adaptation is important.

Psychopathology and traffic violations in subjects who have lost their driving license.

PubMed

Valero, S; Bosch, R; Corominas, M; Giannoni, A; Barrau, V; Ramos-Quiroga, J A; Casas, M

2017-07-01

The persistence of risky behaviors while driving and traffic accidents despite campaigns to increase awareness suggest that there may be underlying causes that maintain proneness to traffic violations. The aim of the current study was to assess: a) the prevalence of psychopathology in a sample of people who have lost their driving license due to former traffic violations and b) the discriminatory capacity of each psychopathological disorder to differentiate among people with high and low proneness to perform risky behaviors while driving. 383 participants in a course to recover their driving license after its loss due to previous traffic violations were included. The International Neuropsychiatric Interview (M.I.N.I.) according to DSM-IV was used to assess psychopathology. Between 67% and 76.2% of the participants had been affected by a lifetime psychopathological disorder until the moment of assessment. The most prevalent diagnoses were substance abuse including alcohol (52.5-62.7%), ADHD (19.7-28.5%), depression (7.9-14.4%) and anxiety (3.6-12.4%). Substance abuse and ADHD also showed the strongest set of associations with specific risk behaviors, but ADHD emerged as the most discriminant disorder to distinguish between those people at high and low risk of while driving. The results of the current study suggest that addressing psychopathology explicitly to prevent risky behaviors and recidivism while driving would provide benefits in this area. Copyright © 2017 Elsevier Inc. All rights reserved.

Examining relationships between anxiety and dangerous driving.

PubMed

Dula, Chris S; Adams, Cristi L; Miesner, Michael T; Leonard, Robin L

2010-11-01

Driving anxiety that has developed following crashes has been studied relatively frequently, but anxiety per se and its effects on driving has not as yet garnered much attention in the literature. The current study included 1121 participants and found higher levels of general anxiety were related to a wide variety of dangerous driving behaviors. While there were clear and expected sex differences on many dangerous driving variables, there were still more such differences with regard to anxiety levels and independent of sex, higher levels of anxiety were associated with greater levels of dangerous driving. Of particular import, it was found that the high anxiety group had caused significantly more crashes and engaged in more DUI episodes than the low and/or medium anxiety groups. Taken as a whole, the results suggest there is a tremendous need for more research in the area of anxiety and dangerous driving and that interventions for highly anxious drivers may well be warranted. 2010 Elsevier Ltd. All rights reserved.

Self-report measures of distractibility as correlates of simulated driving performance.

PubMed

Kass, Steven J; Beede, Kristen E; Vodanovich, Stephen J

2010-05-01

The present study investigated the relationship between self-reported measures pertaining to attention difficulties and simulated driving performance while distracted. Thirty-six licensed drivers participated in a simulator driving task while engaged in a cell phone conversation. The participants completed questionnaires assessing their tendency toward boredom, cognitive failures, and behaviors associated with attention deficit and hyperactivity. Scores on these measures were significantly correlated with various driving outcomes (e.g., speed, lane maintenance, reaction time). Significant relationships were also found between one aspect of boredom proneness (i.e., inability to generate interest or concentrate) and self-reports of past driving behavior (moving violations). The current study may aid in the understanding of how individual differences in driver distractibility may contribute to unsafe driving behaviors and accident involvement. Additionally, such measures may assist in the identification of individuals at risk for committing driving errors due to being easily distracted. The benefits and limitations of conducting and interpreting simulation research are discussed. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

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.

Attention and driving performance modulations due to anger state: Contribution of electroencephalographic data.

PubMed

Techer, Franck; Jallais, Christophe; Corson, Yves; Moreau, Fabien; Ndiaye, Daniel; Piechnick, Bruno; Fort, Alexandra

2017-01-01

Driver internal state, including emotion, can have negative impacts on road safety. Studies have shown that an anger state can provoke aggressive behavior and impair driving performance. Apart from driving, anger can also influence attentional processing and increase the benefits taken from auditory alerts. However, to our knowledge, no prior event-related potentials study assesses this impact on attention during simulated driving. Therefore, the aim of this study was to investigate the impact of anger on attentional processing and its consequences on driving performance. For this purpose, 33 participants completed a simulated driving scenario once in an anger state and once during a control session. Results indicated that anger impacted driving performance and attention, provoking an increase in lateral variations while reducing the amplitude of the visual N1 peak. The observed effects were discussed as a result of high arousal and mind-wandering associated with anger. This kind of physiological data may be used to monitor a driver's internal state and provide specific assistance corresponding to their current needs. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Prediction of driving capacity after traumatic brain injury: a systematic review.

PubMed

Ortoleva, Claudia; Brugger, Camille; Van der Linden, Martial; Walder, Bernhard

2012-01-01

To review the current evidence on predictors for the ability to return to driving after traumatic brain injury. Systematic searches were conducted in MEDLINE, PsycINFO, EMBASE, and CINAHL up to March 1, 2010. Studies were rigorously rated for their methodological content and quality and standardized data were extracted from eligible studies. We screened 2341 articles, of which 7 satisfied our inclusion criteria. Five studies were of limited quality because of undefined, unrepresentative samples and/or absence of blinding. Studies mentioned 38 candidate predictors and tested 37. The candidate predictors most frequently mentioned were "selective attention" and "divided attention" in 4/7 studies, and "executive functions" and "processing speed," both in 3/7 studies. No association with driving was observed for 19 candidate predictors. Eighteen candidate predictors from 3 domains were associated with driving capacity: patient and trauma characteristics, neuropsychological assessments, and general assessments; 10 candidate predictors were tested in only one study and 8 in more than one study. The results of associations were contradictory for all but one: time between trauma and driving evaluation. There is no sound basis at present for predicting driving capacity after traumatic brain injury because most studies have methodological limitations.

Resting state synchrony in long-term abstinent alcoholics: Effects of a current major depressive disorder diagnosis.

PubMed

Fein, George; Camchong, Jazmin; Cardenas, Valerie A; Stenger, Andy

2017-03-01

Alcoholism is characterized by a lack of control over an impulsive and compulsive drive toward excessive alcohol consumption despite significant negative consequences; our previous work demonstrated that successful abstinence is characterized by decreased resting-state synchrony (RSS) as measured with functional magnetic resonance imaging (fMRI), within appetitive drive networks and increased RSS in emotion regulation and inhibitory executive control networks. Our hypothesis is that LTAA (Long-Term Abstinent Alcoholics) with a current major depressive disorder (MDD) drank primarily to deal with the negative affect associated with their MDD and not because of a heightened externalizing diathesis (including heightened appetitive drive), and consequently, in achieving and maintaining abstinence, such individuals would not exhibit the RSS adaptations characteristic of pure alcoholics. We studied 69 NSAC (Non Substance Abusing Controls) and 40 LTAA (8 with current MDD, 32 without a current MDD) using resting-state fMRI and seed based connectivity analyses. In the inhibitory executive control network (nucleus accumbens vs. left dorsolateral prefrontal cortex), LTAA with a current MDD showed increased synchrony compared to NSAC. In the emotion regulation executive control network (subgenual anterior cingulate cortex vs. right dorsolateral prefrontal cortex), LTAA with current MDD did not show increased RSS. In the appetitive drive networks (nucleus accumbens vs, aspects of the caudate nucleus and thalamus), LTAA with a current MDD did not show a reduction of RSS compared to NSAC, but LTAA without a current MDD did. These results suggest different pathways to their alcohol dependence in LTAA with vs. without a current MDD, and different patterns of brain activity in long-term abstinence, suggesting different treatment needs. Copyright © 2016 Elsevier Inc. All rights reserved.

Resting state synchrony in long-term abstinent alcoholics: Effects of a current major depressive disorder diagnosis

PubMed Central

Fein, George; Camchong, Jazmin; Cardenas, Valerie A.; Stenger, Andy

2017-01-01

Alcoholism is characterized by a lack of control over an impulsive and compulsive drive toward excessive alcohol consumption despite significant negative consequences; our previous work demonstrated that successful abstinence is characterized by decreased resting-state synchrony (RSS) as measured with functional magnetic resonance imaging (fMRI), within appetitive drive networks and increased RSS in emotion regulation and inhibitory executive control networks. Our hypothesis is that LTAA (Long-Term Abstinent Alcoholics) with a current major depressive disorder (MDD) drank primarily to deal with the negative affect associated with their MDD and not because of a heightened externalizing diathesis (including heightened appetitive drive), and consequently, in achieving and maintaining abstinence, such individuals would not exhibit the RSS adaptations characteristic of pure alcoholics. We studied 69 NSAC (Non Substance Abusing Controls) and 40 LTAA (8 with current MDD, 32 without a current MDD) using resting-state fMRI and seed based connectivity analyses. In the inhibitory executive control network (nucleus accumbens vs. left dorsolateral prefrontal cortex), LTAA with a current MDD showed increased synchrony compared to NSAC. In the emotion regulation executive control network (subgenual anterior cingulate cortex vs. right dorsolateral prefrontal cortex), LTAA with current MDD did not show increased RSS. In the appetitive drive networks (nucleus accumbens vs, aspects of the caudate nucleus and thalamus), LTAA with a current MDD did not show a reduction of RSS compared to NSAC, but LTAA without a current MDD did. These results suggest different pathways to their alcohol dependence in LTAA with vs. without a current MDD, and different patterns of brain activity in long-term abstinence, suggesting different treatment needs. PMID:28262184

About increasing informativity of diagnostic system of asynchronous electric motor by extracting additional information from values of consumed current parameter

NASA Astrophysics Data System (ADS)

Zhukovskiy, Y.; Korolev, N.; Koteleva, N.

2018-05-01

This article is devoted to expanding the possibilities of assessing the technical state of the current consumption of asynchronous electric drives, as well as increasing the information capacity of diagnostic methods, in conditions of limited access to equipment and incompleteness of information. The method of spectral analysis of the electric drive current can be supplemented by an analysis of the components of the current of the Park's vector. The research of the hodograph evolution in the moment of appearance and development of defects was carried out using the example of current asymmetry in the phases of an induction motor. The result of the study is the new diagnostic parameters of the asynchronous electric drive. During the research, it was proved that the proposed diagnostic parameters allow determining the type and level of the defect. At the same time, there is no need to stop the equipment and taky it out of service for repair. Modern digital control and monitoring systems can use the proposed parameters based on the stator current of an electrical machine to improve the accuracy and reliability of obtaining diagnostic patterns and predicting their changes in order to improve the equipment maintenance systems. This approach can also be used in systems and objects where there are significant parasitic vibrations and unsteady loads. The extraction of useful information can be carried out in electric drive systems in the structure of which there is a power electric converter.

The anti-fatigue driving system design based on the eye blink detect

NASA Astrophysics Data System (ADS)

Yang, Shuyu; Song, Xin; Zhang, Li; Yu, Jie

2017-01-01

Traffic accident is one of the severe social problems in the world, but the appraisal and prevention of the fatigue driving is still a difficult problem that can not be solved. This paper is to study the results of fatigue driving and the existing antifatigue driving products, collecting brain wave with the TGAM (ThinkGear AM) Brain Wave Sensor Chip. We analyze the collected waveform based on eye blink detect algorithm to work out current situation of the driver. According to the analysis results, Sound Module and controllable speed car will make a series of feedback. Finally, an effective Anti- Fatigue Driving System is designed based on all above.

Auto-magnetizing liners for magnetized inertial fusion

DOE PAGES

Slutz, S. A.; Jennings, C. A.; Awe, T. J.; ...

2017-01-20

Here, the MagLIF (Magnetized Liner Inertial Fusion) concept has demonstrated fusion-relevant plasma conditions on the Z accelerator using external field coils to magnetize the fuel before compression. We present a novel concept (AutoMag), which uses a composite liner with helical conduction paths separated by insulating material to provide fuel magnetization from the early part of the drive current, which by design rises slowly enough to avoid electrical breakdown of the insulators. Once the magnetization field is established, the drive current rises more quickly, which causes the insulators to break down allowing the drive current to follow an axial path andmore » implode the liner in the conventional z-pinch manner. There are two important advantages to AutoMag over external field coils for the operation of MagLIF. Low inductance magnetically insulated power feeds can be used to increase the drive current, and AutoMag does not interfere with diagnostic access. Also, AutoMag enables a pathway to energy applications for MagLIF, since expensive field coils will not be damaged each shot. Finally, it should be possible to generate Field Reversed Configurations (FRC) by using both external field coils and AutoMag in opposite polarities. This would provide a means to studying FRC liner implosions on the 100 ns time scale.« less

Current-drive by lower hybrid waves in the presence of energetic alpha-particles

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

Fisch, N.J.; Rax, J.M.

1991-10-01

Many experiments have now proved the effectiveness of lower hybrid waves for driving toroidal current in tokamaks. The use of these waves, however, to provide all the current in a reactor is thought to be uncertain because the waves may not penetrate the center of the more energetic reactor plasma, and, if they did, the wave power may be absorbed by alpha particles rather than by electrons. This paper explores the conditions under which lower-hybrid waves might actually drive all the current. 26 refs.

Low-power transcutaneous current stimulator for wearable applications.

PubMed

Karpul, David; Cohen, Gregory K; Gargiulo, Gaetano D; van Schaik, André; McIntyre, Sarah; Breen, Paul P

2017-10-03

Peripheral neuropathic desensitization associated with aging, diabetes, alcoholism and HIV/AIDS, affects tens of millions of people worldwide, and there is little or no treatment available to improve sensory function. Recent studies that apply imperceptible continuous vibration or electrical stimulation have shown promise in improving sensitivity in both diseased and healthy participants. This class of interventions only has an effect during application, necessitating the design of a wearable device for everyday use. We present a circuit that allows for a low-power, low-cost and small form factor implementation of a current stimulator for the continuous application of subthreshold currents. This circuit acts as a voltage-to-current converter and has been tested to drive + 1 to - 1 mA into a 60 k[Formula: see text] load from DC to 1 kHz. Driving a 60 k[Formula: see text] load with a 2 mA peak-to-peak 1 kHz sinusoid, the circuit draws less than 21 mA from a 9 V source. The minimum operating current of the circuit is less than 12 mA. Voltage compliance is ± 60 V with just 1.02 mA drawn by the high voltage current drive circuitry. The circuit was implemented as a compact 46 mm × 21 mm two-layer PCB highlighting its potential for use in a body-worn device. No design to the best of our knowledge presents comparably low quiescent power with such high voltage compliance. This makes the design uniquely appropriate for low-power transcutaneous current stimulation in wearable applications. Further development of driving and instrumentation circuitry is recommended.

Load theory behind the wheel; perceptual and cognitive load effects.

PubMed

Murphy, Gillian; Greene, Ciara M

2017-09-01

Perceptual Load Theory has been proposed as a resolution to the longstanding early versus late selection debate in cognitive psychology. There is much evidence in support of Load Theory but very few applied studies, despite the potential for the model to shed light on everyday attention and distraction. Using a driving simulator, the effect of perceptual and cognitive load on drivers' visual search was assessed. The findings were largely in line with Load Theory, with reduced distractor processing under high perceptual load, but increased distractor processing under high cognitive load. The effect of load on driving behaviour was also analysed, with significant differences in driving behaviour under perceptual and cognitive load. In addition, the effect of perceptual load on drivers' levels of awareness was investigated. High perceptual load significantly increased inattentional blindness and deafness, for stimuli that were both relevant and irrelevant to driving. High perceptual load also increased RTs to hazards. The current study helps to advance Load Theory by illustrating its usefulness outside of traditional paradigms. There are also applied implications for driver safety and roadway design, as the current study suggests that perceptual and cognitive load are important factors in driver attention. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

What We Know About ADHD and Driving Risk: A Literature Review, Meta-Analysis and Critique

PubMed Central

Jerome, Laurence; Segal, Alvin; Habinski, Liat

2006-01-01

Introduction This article examines the literature on ADHD and unintentional driving injury. This literature has emerged over the last decade as part of the burgeoning epidemic of road traffic death and injury which is the number one cause of death in young adults in North America. Methods The available literature on observational outcome studies and experimental pharmacological interventions is critically reviewed. A meta-analysis of behavioral outcomes and a review of effect size of pharmacological studies are presented. Results Current data support the utility of stimulant medication in improving driving performance in younger ADHD drivers. A conceptual model of risk factors in young ADHD drivers is offered. Conclusion The current state of screening instruments for identifying high risk subjects within this clinical group is summarized along with a final section on emerging trends and future prospects for intervention. PMID:18392181

Cumulative meta-analysis of the relationship between useful field of view and driving performance in older adults: current and future implications.

PubMed

Clay, Olivio J; Wadley, Virginia G; Edwards, Jerri D; Roth, David L; Roenker, Daniel L; Ball, Karlene K

2005-08-01

Driving is a complex behavior that requires the utilization of a wide range of individual abilities. Identifying assessments that not only capture individual differences, but also are related to older adults' driving performance would be beneficial. This investigation examines the relationship between the Useful Field of View (UFOV) assessment and objective measures of retrospective or concurrent driving performance, including state-recorded accidents, on-road driving, and driving simulator performance. The PubMed and PsycINFO databases were searched to retrieve eight studies that reported bivariate relationships between UFOV and these objective driving measures. Cumulative meta-analysis techniques were used to combine the effect sizes in an attempt to determine whether the strength of the relationship was stable across studies and to assess whether a sufficient number of studies have been conducted to validate the relationship between UFOV and driving performance. A within-group homogeneity of effect sizes test revealed that the samples could be thought of as being drawn from the same population, Q [7] = 11.29, p (one-tailed) = 0.13. Therefore, the effect sizes of eight studies were combined for the present cumulative meta-analysis. The weighted mean effect size across the studies revealed a large effect (Cohen's d = 0.945), with poorer UFOV performance associated with negative driving outcomes. This relationship was robust across multiple indices of driving performance and several research laboratories. This convergence of evidence across numerous studies using different methodologies confirms the importance of the UFOV assessment as a valid and reliable index of driving performance and safety. Recent prospective studies have confirmed a relationship between UFOV performance and future crashes, further supporting the use of this instrument as a potential screening measure for at-risk older drivers.

Rapid Drinking is Associated with Increases in Driving-Related Risk-Taking

PubMed Central

Bernosky-Smith, Kimberly A.; Aston, Elizabeth R.; Liguori, Anthony

2014-01-01

Objective The rate of alcohol drinking has been shown to predict impairment on cognitive and behavioral tasks. The current study assessed the influence of speed of alcohol consumption within a laboratory-administered binge on self-reported attitudes toward driving and simulated driving ability. Method Forty moderate drinkers (20 female, 20 male) were recruited from the local community via advertisements for individuals who drank alcohol at least once per month. The equivalent of four standard alcohol drinks was consumed at the participant’s desired pace within a two-hour session. Results Correlation analyses revealed that, after alcohol drinking, mean simulated driving speed, time in excess of speed limit, collisions, and reported confidence in driving were all associated with rapid alcohol drinking. Conclusion Fast drinking may coincide with increased driving confidence due to the extended latency between the conclusion of drinking and the commencement of driving. However, this latency did not reduce alcohol-related driving impairment, as fast drinking was also associated with risky driving. PMID:23027650

Rapid drinking is associated with increases in driving-related risk-taking.

PubMed

Bernosky-Smith, Kimberly A; Aston, Elizabeth R; Liguori, Anthony

2012-11-01

The rate of alcohol drinking has been shown to predict impairment on cognitive and behavioral tasks. The current study assessed the influence of speed of alcohol consumption within a laboratory-administered binge on self-reported attitudes toward driving and simulated driving ability. Forty moderate drinkers (20 female, 20 male) were recruited from the local community via advertisements for individuals who drank alcohol at least once per month. The equivalent of four standard alcohol drinks was consumed at the participant's desired pace within 2-h session. Correlation analyses revealed that, after alcohol drinking, mean simulated driving speed, time in excess of speed limit, collisions, and reported confidence in driving were all associated with rapid alcohol drinking. Fast drinking may coincide with increased driving confidence because of the extended latency between the conclusion of drinking and the commencement of driving. However, this latency did not reduce alcohol-related driving impairment, as fast drinking was also associated with risky driving. Copyright © 2012 John Wiley & Sons, Ltd.

Continuing to drive while sleepy: the influence of sleepiness countermeasures, motivation for driving sleepy, and risk perception.

PubMed

Watling, Christopher N; Armstrong, Kerry A; Obst, Patricia L; Smith, Simon S

2014-12-01

Driver sleepiness is a major contributor to road crashes. The current study sought to examine the association between perceptions of effectiveness of six sleepiness countermeasures and their relationship with self-reports of continuing to drive while sleepy among 309 drivers after controlling for the influence of age, sex, motivation for driving sleepy, and risk perception of sleepy driving. The results demonstrate that the variables of age, sex, motivation, and risk perception were significantly associated with self-reports of continuing to drive while sleepy and only one countermeasure was associated with self-reports of continuing to drive while sleepy. Further, it was found that age differences in self-reports of continuing to drive while sleepy was mediated by participants' motivation and risk perception. These findings highlight modifiable factors that could be focused on with interventions that seek to modify drivers' attitudes and behaviours of driving while sleepy. Copyright © 2014 Elsevier Ltd. All rights reserved.

Risk factors for adverse driving outcomes in Dutch adults with ADHD and controls.

PubMed

Bron, Tannetje I; Bijlenga, Denise; Breuk, Minda; Michielsen, Marieke; Beekman, Aartjan T F; Kooij, J J Sandra

2018-02-01

To identify risk factors for adverse driving outcomes and unsafe driving among adults with and without ADHD in a Dutch sample. In this cross-sectional study, validated self-report questionnaires were used to compare driving history and current driving behavior between 330 adults diagnosed with ADHD and 330 controls. Adults with ADHD had significantly more adverse driving outcomes when compared to controls. Having an ADHD diagnosis significantly increased the odds for having had 3 or more vehicular crashes (OR = 2.72; p = .001). Driving frequency, male gender, age, high anxiety levels, high hostility levels, and alcohol use all significantly influenced the odds for unsafe driving behavior, for having had 12 or more traffic citations, and/or for having had 3 or more vehicular crashes. Alcohol use, and high levels of anxiety and hostility are highly prevalent among adults with ADHD, and they mediate the risk for negative driving outcomes in this group. Copyright © 2017 Elsevier Ltd. All rights reserved.

Base drive circuit for a four-terminal power Darlington

DOEpatents

Lee, Fred C.; Carter, Roy A.

1983-01-01

A high power switching circuit which utilizes a four-terminal Darlington transistor block to improve switching speed, particularly in rapid turn-off. Two independent reverse drive currents are utilized during turn off in order to expel the minority carriers of the Darlington pair at their own charge sweep-out rate. The reverse drive current may be provided by a current transformer, the secondary of which is tapped to the base terminal of the power stage of the Darlington block. In one application, the switching circuit is used in each power switching element in a chopper-inverter drive of an electric vehicle propulsion system.

Current Research Activities in Drive System Technology in Support of the NASA Rotorcraft Program

NASA Technical Reports Server (NTRS)

Handschuh, Robert F.; Zakrajsek, James J.

2006-01-01

Drive system technology is a key area for improving rotorcraft performance, noise/vibration reduction, and reducing operational and manufacturing costs. An overview of current research areas that support the NASA Rotorcraft Program will be provided. Work in drive system technology is mainly focused within three research areas: advanced components, thermal behavior/emergency lubrication system operation, and diagnostics/prognostics (also known as Health and Usage Monitoring Systems (HUMS)). Current research activities in each of these activities will be presented. Also, an overview of the conceptual drive system requirements and possible arrangements for the Heavy Lift Rotorcraft program will be reviewed.

Influence of driving frequency on discharge modes in a dielectric-barrier discharge with multiple current pulses

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

Jiang, Weiman; Tang, Jie; Wang, Yishan

2013-07-15

A one-dimensional self-consistent fluid model was employed to investigate the effect of the driving frequency on the discharge modes in atmospheric-pressure argon discharge with multiple current pulses. The discharge mode was discussed in detail not only at current peaks but also between two adjacent peaks. The simulation results show that different transitions between the Townsend and glow modes during the discharge take place with the driving frequency increased. A complicated transition from the Townsend mode, through glow, Townsend, and glow, and finally back to the Townsend one is found in the discharge with the driving frequency of 8 kHz. Theremore » is a tendency of transition from the Townsend to glow mode for the discharge both at the current peaks and troughs with the increasing frequency. The discharge in the half period can all along operate in the glow mode with the driving frequency high enough. This is resulted from the preservation of more electrons in the gas gap and acquisition of more electron energy from the swiftly varying electric field with the increase in driving frequency. Comparison of the spatial and temporal evolutions of the electron density at different driving frequencies indicates that the increment of the driving frequency allows the plasma chemistry to be enhanced. This electrical characteristic is important for the applications, such as surface treatment and biomedical sterilization.« less

Vehicle ownership and other predictors of teenagers risky driving behavior: Evidence from a naturalistic driving study.

PubMed

Gershon, Pnina; Ehsani, Johnathon; Zhu, Chunming; O'Brien, Fearghal; Klauer, Sheila; Dingus, Tom; Simons-Morton, Bruce

2018-06-08

Risky driving behavior may contribute to the high crash risk among teenage drivers. The current naturalistic driving study assessed predictors for teenagers' kinematic risky driving (KRD) behavior and the interdependencies between them. The private vehicles of 81 novice teenage drivers were equipped with data acquisition system that recorded driving kinematics, miles driven, and video recordings of the driver, passengers and the driving environment. Psychosocial measures were collected using questionnaires administered at licensure. Poisson regression analyses and model selection were used to assess factors associated with teens' risky driving behavior and the interactions between them. Driving own vs shared vehicle, driving during the day vs at night, and driving alone vs with passengers were significantly associated with higher KRD rates (Incidence rate ratios (IRRs) of 1.60, 1.41, and 1.28, respectively). Teenagers reporting higher vs lower levels of parental trust had significantly lower KRD rates (IRR = 0.58). KRD rates were 88% higher among teenagers driving with a passenger in their own vehicle compared to teenagers driving with a passenger in a shared vehicle. Similarly, KRD rates during the day were 74% higher among teenagers driving their own vehicle compared to those driving a shared vehicle. Novice teenagers' risky driving behavior varied according to driver attributes and contextual aspects of the driving environment. As such, examining teenagers' risky driving behavior should take into account multiple contributing factors and their interactions. The variability in risky driving according to the driving context can inform the development of targeted interventions to reduce the crash risk of novice teenage drivers. Copyright © 2018 Elsevier Ltd. All rights reserved.

The influence of cognitive impairment with no dementia on driving restriction and cessation in older adults.

PubMed

Kowalski, Kristina; Love, Janet; Tuokko, Holly; MacDonald, Stuart; Hultsch, David; Strauss, Esther

2012-11-01

Cognitively impaired older adults may be at increased risk of unsafe driving. Individuals with insight into their own impairments may minimize their risk by restricting or stopping driving. The purpose of this study was to examine the influence of cognitive impairment on driving status and driving habits and intentions. Participants were classified as cognitively impaired, no dementia single (CIND-single), CIND-multiple, or not cognitively impaired (NCI) and compared on their self-reported driving status, habits, and intentions to restrict or quit driving in the future. The groups differed significantly in driving status, but not in whether they restricted their driving or reduced their driving frequency. CIND-multiple group also had significantly higher intention to restrict/stop driving than the NCI group. Reasons for restricting and quitting driving were varied and many individuals reported multiple reasons, both external and internal, for their driving habits and intentions. Regardless of cognitive status, none of the current drivers were seriously thinking of restricting or quitting driving in the next 6 months. It will be important to determine, in future research, how driving practices change over time and what factors influence decisions to restrict or stop driving for people with cognitive impairment. Copyright © 2011. Published by Elsevier Ltd.

Brain activity during driving with distraction: an immersive fMRI study

PubMed Central

Schweizer, Tom A.; Kan, Karen; Hung, Yuwen; Tam, Fred; Naglie, Gary; Graham, Simon J.

2013-01-01

Introduction: Non-invasive measurements of brain activity have an important role to play in understanding driving ability. The current study aimed to identify the neural underpinnings of human driving behavior by visualizing the areas of the brain involved in driving under different levels of demand, such as driving while distracted or making left turns at busy intersections. Materials and Methods: To capture brain activity during driving, we placed a driving simulator with a fully functional steering wheel and pedals in a 3.0 Tesla functional magnetic resonance imaging (fMRI) system. To identify the brain areas involved while performing different real-world driving maneuvers, participants completed tasks ranging from simple (right turns) to more complex (left turns at busy intersections). To assess the effects of driving while distracted, participants were asked to perform an auditory task while driving analogous to speaking on a hands-free device and driving. Results: A widely distributed brain network was identified, especially when making left turns at busy intersections compared to more simple driving tasks. During distracted driving, brain activation shifted dramatically from the posterior, visual and spatial areas to the prefrontal cortex. Conclusions: Our findings suggest that the distracted brain sacrificed areas in the posterior brain important for visual attention and alertness to recruit enough brain resources to perform a secondary, cognitive task. The present findings offer important new insights into the scientific understanding of the neuro-cognitive mechanisms of driving behavior and lay down an important foundation for future clinical research. PMID:23450757

Pulse-Width-Modulating Driver for Brushless dc Motor

NASA Technical Reports Server (NTRS)

Salomon, Phil M.

1991-01-01

High-current pulse-width-modulating driver for brushless dc motor features optical coupling of timing signals from low-current control circuitry to high-current motor-driving circuitry. Provides high electrical isolation of motor-power supply, helping to prevent fast, high-current motor-driving pulses from being coupled through power supplies into control circuitry, where they interfere with low-current control signals.

Prediction of Driving Safety in Individuals with Homonymous Hemianopia and Quadrantanopia from Clinical Neuroimaging

PubMed Central

Vaphiades, Michael S.; Kline, Lanning B.; McGwin, Gerald; Owsley, Cynthia; Shah, Ritu; Wood, Joanne M.

2014-01-01

Background. This study aimed to determine whether it is possible to predict driving safety of individuals with homonymous hemianopia or quadrantanopia based upon a clinical review of neuroimages that are routinely available in clinical practice. Methods. Two experienced neuroophthalmologists viewed a summary report of the CT/MRI scans of 16 participants with homonymous hemianopic or quadrantanopic field defects which indicated the site and extent of the lesion and they made predictions regarding whether participants would be safe/unsafe to drive. Driving safety was independently defined at the time of the study using state-recorded motor vehicle crashes (all crashes and at-fault) for the previous 5 years and ratings of driving safety determined through a standardized on-road driving assessment by a certified driving rehabilitation specialist. Results. The ability to predict driving safety was highly variable regardless of the driving safety measure, ranging from 31% to 63% (kappa levels ranged from −0.29 to 0.04). The level of agreement between the neuroophthalmologists was only fair (kappa = 0.28). Conclusions. Clinical evaluation of summary reports of currently available neuroimages by neuroophthalmologists is not predictive of driving safety. Future research should be directed at identifying and/or developing alternative tests or strategies to better enable clinicians to make these predictions. PMID:24683493

Prediction of driving safety in individuals with homonymous hemianopia and quadrantanopia from clinical neuroimaging.

PubMed

Vaphiades, Michael S; Kline, Lanning B; McGwin, Gerald; Owsley, Cynthia; Shah, Ritu; Wood, Joanne M

2014-01-01

Background. This study aimed to determine whether it is possible to predict driving safety of individuals with homonymous hemianopia or quadrantanopia based upon a clinical review of neuroimages that are routinely available in clinical practice. Methods. Two experienced neuroophthalmologists viewed a summary report of the CT/MRI scans of 16 participants with homonymous hemianopic or quadrantanopic field defects which indicated the site and extent of the lesion and they made predictions regarding whether participants would be safe/unsafe to drive. Driving safety was independently defined at the time of the study using state-recorded motor vehicle crashes (all crashes and at-fault) for the previous 5 years and ratings of driving safety determined through a standardized on-road driving assessment by a certified driving rehabilitation specialist. Results. The ability to predict driving safety was highly variable regardless of the driving safety measure, ranging from 31% to 63% (kappa levels ranged from -0.29 to 0.04). The level of agreement between the neuroophthalmologists was only fair (kappa = 0.28). Conclusions. Clinical evaluation of summary reports of currently available neuroimages by neuroophthalmologists is not predictive of driving safety. Future research should be directed at identifying and/or developing alternative tests or strategies to better enable clinicians to make these predictions.

Motorists' knowledge, attitudes and practices toward alcohol-impaired driving/riding in Ghana.

PubMed

Damsere-Derry, James; Palk, Gavan; King, Mark

2017-01-02

The main objective of this study was to establish the knowledge, attitudes, and practices toward drink driving/riding as a risk factor for road traffic crashes in 3 regional capitals in Ghana. The study used a face-to-face approach to randomly sample motorists who were accessing various services at fuel/gas stations, garages, and lorry terminals in 3 cities in Ghana. Over the previous 12 months, 24% of all motorists and 55% of motorists who were current alcohol users reported driving or riding a vehicle within an hour of alcohol intake. On average, motorists/riders who were current alcohol users consumed 4 standard drinks per drinking occasion. Generally, 83% of motorists who currently use alcohol walked, rode, or drove home after consuming alcohol away from their homes. Motorists/riders who reported drink driving were 4 times more likely to have had previous traffic violation arrests compared to those who reported no drink driving/riding (P =.001). Respondents were of the opinion that speeding was the major cause of traffic crashes, followed by driver carelessness, poor road conditions, inexperienced driving, and drink driving, in that order. Thirty-six percent of motorists who use alcohol had the perception that consuming between 6 and 15 standard drinks was the volume of alcohol that will take them to the legal blood alcohol concentration (BAC) limit of 0.08%. Compared to females, male motorists/riders were more likely to report drink driving (adjusted odds ratio [AOR] = 5.15; 95% confidence interval [CI], 2.31 to 11.47). Private motorists also reported a higher likelihood of drink driving compared to commercial drivers (AOR = 3.36; 95% CI, 1.88 to 6.02). Only 4% of motorists knew the legal BAC limit of Ghana and only 2% had ever been tested for drink driving/riding. The volumes of alcohol that motorists typically consume per drinking occasion were very high and their estimates of the number of drinks required to reach the legal BAC limit was also very high. Provision of authoritative information advising motorists about safe, responsible, or low-risk levels of alcohol consumption is imperative. Many traffic violations including drink driving were reported, thus suggesting a need for enhanced policing and enforcement. However, given the low level of knowledge of the legal BAC limit, educating motorists about how many drinks will approximate the legal BAC should be intensified prior to an increase in enforcement; otherwise, the desired outcome of enforcement may not be achieved.

Power-control switch

NASA Technical Reports Server (NTRS)

Kessler, L. L.

1976-01-01

Constant-current source creates drive current independent of input-voltage variations, 50% reduction in power loss in base drive circuitry, maintains essentially constant charge rate, and improves rise-time consistency over input voltage range.

A Study on Kinmen Resident's Perception of Tourism Development and Culture Heritage Impact

ERIC Educational Resources Information Center

Wang, Yi-Ping

2016-01-01

Tourism development could drive the enhancement of national income and the demands for international tourism that tourism benefits have become the key source of national revenue. The integration of cultural relics with tourism development to drive the national or regional development has currently become the world trend. Making good use of the…

Driving with Pets as a Risk Factor for Motor Vehicle Collisions among Older Drivers

PubMed Central

Blunck, Hallie; Owsley, Cynthia; MacLennan, Paul A.; McGwin, Gerald

2015-01-01

Increasing rates of distraction-related motor vehicle collisions (MVCs) continue to raise concerns regarding driving safety. This study sought to evaluate a novel driving-related distraction, driving with a pet, as a risk factor for MVCs among older, community dwelling adults. Two thousand licensed drivers aged 70 and older were identified, of whom 691 reported pet ownership. Comparing pet owners who did and did not drive with their pets, neither overall MVC rates (rate ratio [RR] 0.97 95% confidence interval [CI] 0.75–1.26) nor at-fault MVC rates (RR 0.84 95% CI 0.57–1.24) were elevated. However, those who reported always driving with a pet in the vehicle had an elevated MVC rate (RR 1.89 95% CI 1.10–3.25), as compared to those who did not drive with a pet. The MVC rate was not increased for those reporting only sometimes or rarely driving with a pet in the vehicle. The current study demonstrates an increased risk of MVC involvement in those older drivers who always take a pet with them when they drive a vehicle. When confronted with an increased cognitive or physical workload while driving, elderly drivers in prior studies have exhibited slower cognitive performance and delayed response times in comparison to younger age groups. Further study of pet-related distracted driving behaviors among older drivers as well as younger populations with respect to driver safety and performance is warranted to appropriately inform the need for policy regulation on this issue. PMID:23708755

Driving with pets as a risk factor for motor vehicle collisions among older drivers.

PubMed

Blunck, Hallie; Owsley, Cynthia; MacLennan, Paul A; McGwin, Gerald

2013-09-01

Increasing rates of distraction-related motor vehicle collisions (MVCs) continue to raise concerns regarding driving safety. This study sought to evaluate a novel driving-related distraction, driving with a pet, as a risk factor for MVCs among older, community dwelling adults. Two thousand licensed drivers aged 70 and older were identified, of whom 691 reported pet ownership. Comparing pet owners who did and did not drive with their pets, neither overall MVC rates (rate ratio [RR] 0.97, 95% confidence interval [CI] 0.75-1.26) nor at-fault MVC rates (RR 0.84, 95% CI 0.57-1.24) were elevated. However, those who reported always driving with a pet in the vehicle had an elevated MVC rate (RR 1.89, 95% CI 1.10-3.25), as compared to those who did not drive with a pet. The MVC rate was not increased for those reporting only sometimes or rarely driving with a pet in the vehicle. The current study demonstrates an increased risk of MVC involvement in those older drivers who always take a pet with them when they drive a vehicle. When confronted with an increased cognitive or physical workload while driving, elderly drivers in prior studies have exhibited slower cognitive performance and delayed response times in comparison to younger age groups. Further study of pet-related distracted driving behaviors among older drivers as well as younger populations with respect to driver safety and performance is warranted to appropriately inform the need for policy regulation on this issue. Published by Elsevier Ltd.

Sensorless Sinusoidal Drives for Fan and Pump Motors by V/f Control

NASA Astrophysics Data System (ADS)

Kiuchi, Mitsuyuki; Ohnishi, Tokuo

This paper proposes sensorless sinusoidal driving methods of permanent magnet synchronous motors for fans and pumps by V/f control. The proposed methods are simple methods that control the motor peak current constant by voltage or frequency control, and are characterized by DC link current detection using a single shunt resistor at carrier wave signal bottom timing. As a result of the dumping factor from square torque load characteristics of fan and pump motors, it is possible to control stable starting and stable steady state by V/f control. In general, pressure losses as a result of the fluid pass of fan and pump systems are nearly constant; therefore, the flow rate and motor torque are determined by revolutions. Accordingly, high efficiency driving is possible by setting corresponding currents to q-axis currents (torque currents) at target revolutions. Because of the simple current detection and motor control methods, the proposed methods are optimum for fan and pump motor driving systems of home appliances.

Lower hybrid current drive experiments in the HT-6M tokamak

NASA Astrophysics Data System (ADS)

Jiang, Tongwen; Liu, Yuexiu; Guo, Wenkang; Zhang, Xuelei; Luo, Jiarong

1987-07-01

Lower hybrid current drive (LHCD) experiments with a multijunction grill have been performed in the HT-6M tokamak. When the RF power pulse with 15ms risetime is injected into the plasma, the toroidal current amplitude is raised, but the temporal variation of the loop voltage does not have measurable change. The efficiency of current drive is Irf/Prf=0.57kA/kW at bar ne=3 × 1012cm-3 and Bt=8KG. It seems that the multijunction grill has the same efficiency as the ordinary grill on the LHCD experiments.

Glaucoma and quality of life: fall and driving risk.

PubMed

Montana, Cynthia L; Bhorade, Anjali M

2018-03-01

Numerous population-based studies suggest that glaucoma is an independent risk factor for falling and motor vehicle collisions, particularly for older adults. These adverse events lead to increased healthcare expenditures and decreased quality of life. Current research priorities, therefore, include identifying factors that predispose glaucoma patients to falling and unsafe driving, and developing screening strategies and targeted rehabilitation. The purpose of this article is to review recent studies that address these priorities. Studies continue to support that glaucoma patients, particularly those with advanced disease, have an increased risk of falling or unsafe driving. Risk factors, however, remain variable and include severity and location of visual field defects, contrast sensitivity, and performance on divided attention tasks. Such variability is likely because of the multifactorial nature of ambulating and driving and compensatory strategies used by patients. Falls and unsafe driving remain a serious public health issue for older adults with glaucoma. Ambulation and driving are complex tasks and there is no consensus yet, regarding the best methods for risk stratification and targeted interventions to increase safety. Therefore, comprehensive and individualized assessments are recommended to most effectively evaluate a patient's risk for falling or unsafe driving.

Analytical approaches to optimizing system "Semiconductor converter-electric drive complex"

NASA Astrophysics Data System (ADS)

Kormilicin, N. V.; Zhuravlev, A. M.; Khayatov, E. S.

2018-03-01

In the electric drives of the machine-building industry, the problem of optimizing the drive in terms of mass-size indicators is acute. The article offers analytical methods that ensure the minimization of the mass of a multiphase semiconductor converter. In multiphase electric drives, the form of the phase current at which the best possible use of the "semiconductor converter-electric drive complex" for active materials is different from the sinusoidal form. It is shown that under certain restrictions on the phase current form, it is possible to obtain an analytical solution. In particular, if one assumes the shape of the phase current to be rectangular, the optimal shape of the control actions will depend on the width of the interpolar gap. In the general case, the proposed algorithm can be used to solve the problem under consideration by numerical methods.

Prevalence and correlates of drink driving within patrons of Australian night-time entertainment precincts.

PubMed

Curtis, Ashlee; Coomber, Kerri; Hyder, Shannon; Droste, Nic; Pennay, Amy; Jenkinson, Rebecca; Mayshak, Richelle; Miller, Peter G

2016-10-01

Drink driving is a significant public health concern, and contributes to many road fatalities worldwide. The current study is the first to examine the prevalence and correlates of drink driving behavior in a sample of night-time entertainment precinct attendees in Australia. Interviews were conducted with 4214 night-time entertainment precinct attendees in two metropolitan and three regional cities in Australia. Seven correlates of self-reported drink driving were examined: gender, age, occupation, blood alcohol concentration (BAC), alcohol consumed prior to attending a licensed venue, energy drink consumption, and other drug consumption. Fourteen percent of night-time entertainment precinct attendees reported drink driving in the past three months. Bivariate logistic regression models indicated that males were significantly more likely than females to report drink driving in the past three months. Blue-collar workers and sales/clerical/administrative workers were significantly more likely to report drink driving behavior in the past three months than white-collar workers. The likelihood of reporting drink driving during the three months prior to interview significantly increased as BAC on the current night out increased, and when patrons reported engaging in pre-drinking or other drug use. The multivariate model presented a similar pattern of results, however BAC and pre-drinking on the night of the interview were no longer independent significant predictors. Males, blue collar/sales/clerical/administrative workers, and illicit drug consumers were more likely to report engaging in drink driving behavior than their counterparts. Interventions should focus on addressing the considerable proportion night-time entertainment precinct attendees who report engaging in drink driving behavior. Copyright © 2016 Elsevier Ltd. All rights reserved.

Distraction produces over-additive increases in the degree to which alcohol impairs driving performance.

PubMed

Van Dyke, Nicholas A; Fillmore, Mark T

2015-12-01

Research indicates that alcohol intoxication and increased demands on drivers' attention from distractions (e.g., passengers and cell phones) contribute to poor driving performance and increased rates of traffic accidents and fatalities. The present study examined the separate and combined effects of alcohol and distraction on simulated driving performance at blood alcohol concentrations (BrACs) below the legal driving limit in the USA (i.e., 0.08 %). Fifty healthy adult drivers (36 men and 14 women) were tested in a driving simulator following a 0.65-g/kg dose of alcohol and a placebo. Drivers completed two drive tests: a distracted drive, which included a two-choice detection task, and an undistracted control drive. Multiple indicators of driving performance, such as drive speed, within-lane deviation, steering rate, and lane exceedances were measured. Alcohol and distraction each impaired measures of driving performance. Moreover, the magnitude of alcohol impairment was increased by at least twofold when tested under the distracting versus the undistracted condition. The findings highlight the need for a clearer understanding of how common distractions impact intoxicated drivers, especially at BrACs that are currently legal for driving in the USA.

Driving styles among young novice drivers--the contribution of parental driving styles and personal characteristics.

PubMed

Miller, Gila; Taubman-Ben-Ari, Orit

2010-03-01

As part of the effort to ascertain why young drivers are more at risk for car crashes, attention has recently turned to the effects of family, including the intergenerational transmission of driving styles from parents to offspring. The current study sought to further understanding of the nature and aspects of the family influence with the help of Bowen's family systems theory. In Phase 1 of the prospective study, 130 young driving students completed questionnaires tapping personal and personality measures, and their parents completed driving-related instruments. In Phase 2, a year after the young drivers had obtained their driver's license, they were administered the same questionnaires their parents had previously completed. The results show significant correlations between the parents' driving styles and those of their offspring a year after licensure. Furthermore, differentiation of self and self-efficacy in newly acquired driving skills were found to moderate or heighten the similarity between the driving styles of parents and their offspring. For young drivers reporting anxiety in Phase 1, this was associated with a reported anxious driving style a year later. Among young female drivers, anxiety was also associated with a reckless and careless style. Higher sensation seeking was related to higher reckless driving among young male drivers. The findings are discussed in the context of adolescence and the role of the study variables in the development and intergenerational transmission of driving styles. In addition to its theoretical contribution to the realms of intergenerational transmission in general, and young drivers in particular, the study may have practical implications for both family therapy and the design of driving interventions. Copyright 2009 Elsevier Ltd. All rights reserved.

The effects of electron cyclotron heating and current drive on toroidal Alfvén eigenmodes in tokamak plasmas

NASA Astrophysics Data System (ADS)

Sharapov, S. E.; Garcia-Munoz, M.; Van Zeeland, M. A.; Bobkov, B.; Classen, I. G. J.; Ferreira, J.; Figueiredo, A.; Fitzgerald, M.; Galdon-Quiroga, J.; Gallart, D.; Geiger, B.; Gonzalez-Martin, J.; Johnson, T.; Lauber, P.; Mantsinen, M.; Nabais, F.; Nikolaeva, V.; Rodriguez-Ramos, M.; Sanchis-Sanchez, L.; Schneider, P. A.; Snicker, A.; Vallejos, P.; the AUG Team; the EUROfusion MST1 Team

2018-01-01

Dedicated studies performed for toroidal Alfvén eigenmodes (TAEs) in ASDEX-Upgrade (AUG) discharges with monotonic q-profiles have shown that electron cyclotron resonance heating (ECRH) can make TAEs more unstable. In these AUG discharges, energetic ions driving TAEs were obtained by ion cyclotron resonance heating (ICRH). It was found that off-axis ECRH facilitated TAE instability, with TAEs appearing and disappearing on timescales of a few milliseconds when the ECRH power was switched on and off. On-axis ECRH had a much weaker effect on TAEs, and in AUG discharges performed with co- and counter-current electron cyclotron current drive (ECCD), the effects of ECCD were found to be similar to those of ECRH. Fast ion distributions produced by ICRH were computed with the PION and SELFO codes. A significant increase in T e caused by ECRH applied off-axis is found to increase the fast ion slowing-down time and fast ion pressure causing a significant increase in the TAE drive by ICRH-accelerated ions. TAE stability calculations show that the rise in T e causes also an increase in TAE radiative damping and thermal ion Landau damping, but to a lesser extent than the fast ion drive. As a result of the competition between larger drive and damping effects caused by ECRH, TAEs become more unstable. It is concluded, that although ECRH effects on AE stability in present-day experiments may be quite significant, they are determined by the changes in the plasma profiles and are not particularly ECRH specific.

Control task substitution in semiautomated driving: does it matter what aspects are automated?

PubMed

Carsten, Oliver; Lai, Frank C H; Barnard, Yvonne; Jamson, A Hamish; Merat, Natasha

2012-10-01

The study was designed to show how driver attention to the road scene and engagement of a choice of secondary tasks are affected by the level of automation provided to assist or take over the basic task of vehicle control. It was also designed to investigate the difference between support in longitudinal control and support in lateral control. There is comparatively little literature on the implications of automation for drivers' engagement in the driving task and for their willingness to engage in non-driving-related activities. A study was carried out on a high-level driving simulator in which drivers experienced three levels of automation: manual driving, semiautomated driving with either longitudinal or lateral control provided, and highly automated driving with both longitudinal and lateral control provided. Drivers were free to pay attention to the roadway and traffic or to engage in a range of entertainment and grooming tasks. Engagement in the nondriving tasks increased from manual to semiautomated driving and increased further with highly automated driving. There were substantial differences in attention to the road and traffic between the two types of semiautomated driving. The literature on automation and the various task analyses of driving do not currently help to explain the effects that were found. Lateral support and longitudinal support may be the same in terms of levels of automation but appear to be regarded rather differently by drivers.

Improved InGaN LED System Efficacy and Cost via Droop Reduction

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

Wildeson, Isaac

Efficiency droop is a non-thermal process intrinsic to indium gallium nitride light emitting diodes (LEDs) in which the external quantum efficiency (EQE) decreases with increasing drive current density. Mitigating droop would allow one to reduce the size of LEDs driven at a given current or to drive LEDs of given size at higher current while maintaining high efficiencies. In other words, droop mitigation can lead to significant gains in light output per dollar and/or light output per watt of input power. This project set an EQE improvement goal at high drive current density which was to be attained by improvingmore » the LED active region design and growth process following a droop mitigation strategy. The interactions between LED active region design parameters and efficiency droop were studied by modeling and experiments. The crystal defects that tend to form in more complex LED designs intended to mitigate droop were studied with advanced characterization methods that provided insight into the structural and electronic properties of the material. This insight was applied to improve the epitaxy process both in terms of active region design and optimization of growth parameters. The final project goals were achieved on schedule and an epitaxy process leading to LEDs with EQE exceeding the project target was demonstrated.« less

Driving reduction and cessation : transitioning to not driving.

DOT National Transportation Integrated Search

2009-09-01

This project examined the process of driving reduction and cessation from the perspective of older adults (current and former drivers) and adult children. The objectives were to identify common markers of the process of driving cessation and to gain ...

Eccentric figure-eight coils for transcranial magnetic stimulation.

PubMed

Sekino, Masaki; Ohsaki, Hiroyuki; Takiyama, Yoshihiro; Yamamoto, Keita; Matsuzaki, Taiga; Yasumuro, Yoshihiro; Nishikawa, Atsushi; Maruo, Tomoyuki; Hosomi, Koichi; Saitoh, Youichi

2015-01-01

Previously we proposed an eccentric figure-eight coil that can cause threshold stimulation in the brain at lower driving currents. In this study, we performed numerical simulations and magnetic stimulations to healthy subjects for evaluating the advantages of the eccentric coil. The simulations were performed using a simplified spherical brain model and a realistic human brain model. We found that the eccentric coil required a driving current intensity of approximately 18% less than that required by the concentric coil to cause comparable eddy current densities within the brain. The eddy current localization of the eccentric coil was slightly higher than that of the concentric coil. A prototype eccentric coil was designed and fabricated. Instead of winding a wire around a bobbin, we cut eccentric-spiral slits on the insulator cases, and a wire was woven through the slits. The coils were used to deliver magnetic stimulation to healthy subjects; among our results, we found that the current slew rate corresponding to motor threshold values for the concentric and eccentric coils were 86 and 78 A/µs, respectively. The results indicate that the eccentric coil consistently requires a lower driving current to reach the motor threshold than the concentric coil. Future development of compact magnetic stimulators will enable the treatment of some intractable neurological diseases at home. © 2014 Wiley Periodicals, Inc.

Status of Electron Bernstein Wave (EBW) Research on NSTX and CDX-U

NASA Astrophysics Data System (ADS)

Taylor, G.; Efthimion, P. C.; Jones, B. M.; Wilson, J. R.; Wilgen, J. B.; Bell, G. L.; Bigelow, T. S.; Rasmussen, D. A.; Ram, A. K.; Bers, A.; Harvey, R. W.

2002-11-01

Recent studies of EBWs, via mode conversion (MC) to X-mode electromagnetic radiation on the CDX-U and NSTX spherical torus (ST) plasmas, support the use of EBWs to measure the Te profile and allow local heating and current drive in ST plasmas. An in-vessel antenna with a local adjustable limiter has successfully controlled the density scale length at the MC layer in CDX-U increasing the MC by an order of magnitude to ˜ 100%. A similar technique on NSTX has so far increased MC efficiency fivefold to ˜ 50%. Both results are in good agreement with theoretical predictions. Experiments focused on achieving >= 80% MC on NSTX are planned for the coming year. Ray tracing and Fokker-Planck modeling support the design of a ˜ 1 MW EBW heating and current drive system for NSTX that will assist plasma startup, locally heat electrons, drive non-inductive current and may suppress tearing modes or other MHD that limit high β operation.

Anomalous-viscosity current drive

DOEpatents

Stix, T.H.; Ono, M.

1986-04-25

The present invention relates to a method and apparatus for maintaining a steady-state current for magnetically confining the plasma in a toroidal magnetic confinement device using anomalous viscosity current drive. A second aspect of this invention relates to an apparatus and method for the start-up of a magnetically confined toroidal plasma.

Motorized mobility scooters – The use of training/intervention and technology for improving driving skills in aging adults - A Mini-Review

PubMed Central

Toosizadeh, Nima; Bunting, Matthew; Howe, Carol; Mohler, Jane; Sprinkle, Jonathan; Najafi, Bijan

2014-01-01

Background Motorized mobility scooters (MMS) have become the most acceptable powered assistive device for those with impaired mobility, who have sufficient upper body strength and dexterity, and postural stability. Although several benefits have been attributed to MMS usage, there are likewise risks of use, including injuries and even deaths. Objective The aim of the current review was to summarize results from clinical studies regarding the enhancement of MMS driver safety with a primary focus on improving driving skills/performance using clinical approaches. We addressed three main objectives: 1) to identify and summarize any available evidence (strong, moderate, or weak evidence based on the quality of studies) regarding improved driving skills/performance following training/intervention; 2) to identify types of driving skills/performance that might be improved by training/intervention; and 3) to identify the use of technology in improving MMS performance or training procedure. Methods Articles were searched for in the following medical and engineering electronic databases: PubMed, Cochrane Library, Web of Science, ClinicalTrials.gov, PsycINFO, CINAHL, ERIC, EI Compendix, IEEE Explore, and REHABDATA. Inclusion criteria included: aging adults or those with ambulatory problems; intervention or targeted training; and clinical trial. Outcomes included: MMS skills/performance. Results Six articles met the inclusion criteria and are analyzed in this review. Four of the six articles contained training approaches for MMS drivers including skill trainings using real MMS inside and outside (i.e., in community) and in a 3D virtual environment. The other two studies contain infrastructural assessments (i.e., the minimum space required for safe maneuverability of MMS users) and additional mobility assistance tools to improve maneuverability and to enhance driving performance. Conclusions Results from the current review showed improved driving skills/performance by training, infrastructural assessments, and incorporating mobility assistance tools. MMS driving skills that can be improved through driver training include: weaving, negotiating with and avoiding pedestrian interference, simultaneous reading of signs and obstacle avoidance in path, level driving, forward and reverse driving, figure 8s, turning in place, crossing left slope, maneuvering down a 2-inch curb, and driving up and down inclines. However, several limitations exist in the available literature regarding evidence of improved driving skills/performance following training/intervention, such as small sample sizes, lack of control groups and statistical analysis. PMID:24481257

Alcohol and Traffic Safety.

ERIC Educational Resources Information Center

Dickman, Frances Baker, Ed.

1988-01-01

Seven papers discuss current issues and applied social research concerning alcohol traffic safety. Prevention, policy input, methodology, planning strategies, anti-drinking/driving programs, social-programmatic orientations of Mothers Against Drunk Driving, Kansas Driving Under the Influence Law, New Jersey Driving While Impaired Programs,…

High speed, high current pulsed driver circuit

DOEpatents

Carlen, Christopher R.

2017-03-21

Various technologies presented herein relate to driving a LED such that the LED emits short duration pulses of light. This is accomplished by driving the LED with short duration, high amplitude current pulses. When the LED is driven by short duration, high amplitude current pulses, the LED emits light at a greater amplitude compared to when the LED is driven by continuous wave current.

Effects of altruism and burnout on driving behavior of bus drivers.

PubMed

Shi, Xia; Zhang, Liang

2017-05-01

Personality traits predict driving behaviors. However, the mechanism underlying this relationship has not been adequately investigated in professional drivers. The current study investigated the relationship between altruistic personality and aberrant driving behaviors, and the potential role of burnout. A total of 194 bus drivers completed questionnaires including measures of altruism, burnout and aberrant driving behaviors (aggressive violations, ordinary violations, errors, and lapses). The results showed that altruism was negatively correlated with burnout, and with all the four subcategories of aberrant driving behavior. Burnout fully mediated the relationship between altruism and aggressive violations, and partially mediated the relationship between altruism and lapses. These findings can be applied in the bus drivers' selection and interventions for burnout in order to improve the safety of public transport. Copyright © 2017 Elsevier Ltd. All rights reserved.

Brain activation during fast driving in a driving simulator: the role of the lateral prefrontal cortex.

PubMed

Jäncke, Lutz; Brunner, Béatrice; Esslen, Michaela

2008-07-16

Little is currently known about the neural underpinnings of the cognitive control of driving behavior in realistic situations and of the driver's speeding behavior in particular. In this study, participants drove in realistic scenarios presented in a high-end driving simulator. Scalp-recorded EEG oscillations in the alpha-band (8-13 Hz) with a 30-electrode montage were recorded while the participants drove under different conditions: (i) excessively fast (Fast), (ii) in a controlled manner at a safe speed (Correct), and (iii) impatiently in the context of testing traffic conditions (Impatient). Intracerebral sources of alpha-band activation were estimated using low resolution electrical tomography. Given that previous studies have shown a strong negative correlation between the Bold response in the frontal cortex and the alpha-band power, we used alpha-band-related activity as an estimation of frontal activation. Statistical analysis revealed more alpha-band-related activity (i.e. less neuronal activation) in the right lateral prefrontal cortex, including the dorsolateral prefrontal cortex, during fast driving. Those participants who speeded most and exhibited greater risk-taking behavior demonstrated stronger alpha-related activity (i.e. less neuronal activation) in the left anterior lateral prefrontal cortex. These findings are discussed in the context of current theories about the role of the lateral prefrontal cortex in controlling risk-taking behavior, task switching, and multitasking.

Gear Design Effects on the Performance of High Speed Helical Gear Trains as Used in Aerospace Drive Systems

NASA Technical Reports Server (NTRS)

Handschuh, R.; Kilmain, D.; Ehinger, R.; Sinusas, E.

2013-01-01

The performance of high-speed helical gear trains is of particular importance for tiltrotor aircraft drive systems. These drive systems are used to provide speed reduction/torque multiplication from the gas turbine output shaft and provide the necessary offset between these parallel shafts in the aircraft. Four different design configurations have been tested in the NASA Glenn Research Center, High Speed Helical Gear Train Test Facility. The design configurations included the current aircraft design, current design with isotropic superfinished gear surfaces, double helical design (inward and outward pumping), increased pitch (finer teeth), and an increased helix angle. All designs were tested at multiple input shaft speeds (up to 15,000 rpm) and applied power (up to 5,000 hp). Also two lubrication, system-related, variables were tested: oil inlet temperature (160 to 250 F) and lubricating jet pressure (60 to 80 psig). Experimental data recorded from these tests included power loss of the helical system under study, the temperature increase of the lubricant from inlet to outlet of the drive system and fling off temperatures (radially and axially). Also, all gear systems were tested with and without shrouds around the gears. The empirical data resulting from this study will be useful to the design of future helical gear train systems anticipated for next generation rotorcraft drive systems.

Gear Design Effects on the Performance of High Speed Helical Gear Trains as Used in Aerospace Drive Systems

NASA Technical Reports Server (NTRS)

Handschuh, R.; Kilmain, C.; Ehinger, R.; Sinusas, E.

2013-01-01

The performance of high-speed helical gear trains is of particular importance for tiltrotor aircraft drive systems. These drive systems are used to provide speed reduction / torque multiplication from the gas turbine output shaft and provide the necessary offset between these parallel shafts in the aircraft. Four different design configurations have been tested in the NASA Glenn Research Center, High Speed Helical Gear Train Test Facility. The design configurations included the current aircraft design, current design with isotropic superfinished gear surfaces, double helical design (inward and outward pumping), increased pitch (finer teeth), and an increased helix angle. All designs were tested at multiple input shaft speeds (up to 15,000 rpm) and applied power (up to 5,000 hp). Also two lubrication, system-related, variables were tested: oil inlet temperature (160 to 250 degF) and lubricating jet pressure (60 to 80 psig). Experimental data recorded from these tests included power loss of the helical system under study, the temperature increase of the lubricant from inlet to outlet of the drive system and fling off temperatures (radially and axially). Also, all gear systems were tested with and without shrouds around the gears. The empirical data resulting from this study will be useful to the design of future helical gear train systems anticipated for next generation rotorcraft drive systems.

The effects of cognitively demanding dual-task driving condition on elderly people's driving performance; Real driving monitoring.

PubMed

Ebnali, Mahdi; Ahmadnezhad, Pedram; Shateri, Alireza; Mazloumi, Adel; Ebnali Heidari, Majid; Nazeri, Ahmad Reza

2016-09-01

Using in-vehicle audio technologies such as audio systems and voice messages is regarded as a common secondary task. Such tasks, known as the sources of non-visual distraction, affect the driving performance. Given the elderly drivers' cognitive limitations, driving can be even more challenging to drivers. The current study examined how listening to economic news, as a cognitively demanding secondary task, affects elderly subjects' driving performance and whether their comprehension accuracy is associated with these effects. Participants of the study (N=22) drove in a real condition with and without listening to economic news. Measurements included driving performance (speed control, forward crash risk, and lateral lane position) and task performance (comprehension accuracy). The mean driving speed, duration of driving in unsafe zones and numbers of overtaking decreased significantly when drivers were engaged in the dual-task condition. Moreover, the cognitive secondary task led to a higher speed variability. Our results demonstrate that there was not a significant relationship between the lane changes and the activity of listening to economic news. However, a meaningful difference was observed between general comprehension and deep comprehension on the one hand and driving performance on the other. Another aspect of our study concerning the drivers' ages and their comprehension revealed a significant relationship between age above 75 and comprehension level. Drivers aging 75 and older showed a lower level of deep comprehension. Our study demonstrates that elderly drivers compensated driving performance with safety margin adoption while they were cognitively engaged. In this condition, however, maintaining speed proved more demanding for drivers aging 75 and older. Copyright © 2016 Elsevier Ltd. All rights reserved.

Driving and legal status of Spanish opioid-dependent patients.

PubMed

Roncero, Carlos; Álvarez, F Javier; Barral, Carmen; Gómez-Baeza, Susana; Gonzalvo, Begoña; Rodríguez-Cintas, Laia; Brugal, M Teresa; Jacas, Carlos; Romaguera, Anna; Casas, Miguel

2013-06-03

Opioid dependent patients have legal problems, driving violations and accidents more frequently than the general population. We have hypothesized that those patients currently driving may have better legal outcomes than those who do not possess a valid driving license. With this aim we have analyzed the information gathered in the PROTEUS study regarding the legal and driving statuses and assessed the possible association between them. The PROTEUS study was an observational, cross-sectional, descriptive, multicenter nationwide representative study, conducted in Spanish healthcare centers for opioid dependent patients. The driving and legal statuses of a population of opioid dependent patients ≥ 18 years and enrolled in Opioid Agonist Therapy treatment centers in Spain, were assessed using a short specific questionnaire and the EuropASI questionnaire to highlight distinct individual clinical needs. 621 patients were evaluable (84% men, 24.5% active workers). 321 patients (52%) drove on a regular basis. Nineteen percent of patients had some problem with the criminal justice system. There was a significant difference (p = 0.0433) in status, according to the criminal justice system, between patients who drove on a regular basis and those who did not, with a higher percentage of patients with non-pending charges among usual drivers. Regular drivers showed fewer legal problems than non-regular drivers, with the exception of those related to driving (driving violations and drunk driving). Driving is a good prognostic factor for the social integration of the patients and policies should be implemented to enable these patients to drive safely under medical authorization. The legal description will be useful to assess treatment efficacy.

Driving and legal status of Spanish opioid-dependent patients

PubMed Central

2013-01-01

Background Opioid dependent patients have legal problems, driving violations and accidents more frequently than the general population. We have hypothesized that those patients currently driving may have better legal outcomes than those who do not possess a valid driving license. With this aim we have analyzed the information gathered in the PROTEUS study regarding the legal and driving statuses and assessed the possible association between them. The PROTEUS study was an observational, cross-sectional, descriptive, multicenter nationwide representative study, conducted in Spanish healthcare centers for opioid dependent patients. Findings The driving and legal statuses of a population of opioid dependent patients ≥18 years and enrolled in Opioid Agonist Therapy treatment centers in Spain, were assessed using a short specific questionnaire and the EuropASI questionnaire to highlight distinct individual clinical needs. 621 patients were evaluable (84% men, 24.5% active workers). 321 patients (52%) drove on a regular basis. Nineteen percent of patients had some problem with the criminal justice system. There was a significant difference (p = 0.0433) in status, according to the criminal justice system, between patients who drove on a regular basis and those who did not, with a higher percentage of patients with non-pending charges among usual drivers. Conclusions Regular drivers showed fewer legal problems than non-regular drivers, with the exception of those related to driving (driving violations and drunk driving). Driving is a good prognostic factor for the social integration of the patients and policies should be implemented to enable these patients to drive safely under medical authorization. The legal description will be useful to assess treatment efficacy. PMID:23731546

On-road emission factors of PM pollutants for light-duty vehicles (LDVs) based on urban street driving conditions

NASA Astrophysics Data System (ADS)

Kam, Winnie; Liacos, James W.; Schauer, James J.; Delfino, Ralph J.; Sioutas, Constantinos

2012-12-01

An on-road sampling campaign was conducted on two major surface streets (Wilshire and Sunset Boulevards) in Los Angeles, CA, to characterize PM components including metals, trace elements, and organic species for three PM size fractions (PM10-2.5, PM2.5-0.25, and PM0.25). Fuel-based emission factors (mass of pollutant per kg of fuel) were calculated to assess the emissions profile of a light-duty vehicle (LDV) traffic fleet characterized by stop-and-go driving conditions that are reflective of urban street driving. Emission factors for metals and trace elements were highest in PM10-2.5 while emission factors for PAHs and hopanes and steranes were highest in PM0.25. PM2.5 emission factors were also compared to previous freeway, roadway tunnel, and dynamometer studies based on an LDV fleet to determine how various environments and driving conditions may influence concentrations of PM components. The on-road sampling methodology deployed in the current study captured substantially higher levels of metals and trace elements associated with vehicular abrasion (Fe, Ca, Cu, and Ba) and crustal origins (Mg and Al) than previous LDV studies. The semi-volatile nature of PAHs resulted in higher levels of PAHs in the particulate phase for LDV tunnel studies (Phuleria et al., 2006) and lower levels of PAHs in the particulate phase for freeway studies (Ning et al., 2008). With the exception of a few high molecular weight PAHs, the current study's emission factors were in between the LDV tunnel and LDV freeway studies. In contrast, hopane and sterane emission factors were generally comparable between the current study, the LDV tunnel, and LDV freeway, as expected given the greater atmospheric stability of these organic compounds. Overall, the emission factors from the dynamometer studies for metals, trace elements, and organic species are lower than the current study. Lastly, n-alkanes (C19-C40) were quantified and alkane carbon preference indices (CPIs) were determined to be in the range of 1-2, indicating substantial anthropogenic source contribution for surface streets in Los Angeles.

Status of Credentialing Structures Related to Secondary Transition: A State-Level Policy Analysis

ERIC Educational Resources Information Center

Simonsen, Monica L.; Novak, Jeanne A.; Mazzotti, Valerie L.

2018-01-01

To understand the current status of transition-related credentialing systems in driving personnel preparation, it is necessary to identify which state education and rehabilitation services agencies are currently providing certification and licensure in the area of secondary transition. The purpose of this study was to examine the current state of…

Reduced ion bootstrap current drive on NTM instability

NASA Astrophysics Data System (ADS)

Qu, Hongpeng; Wang, Feng; Wang, Aike; Peng, Xiaodong; Li, Jiquan

2018-05-01

The loss of bootstrap current inside magnetic island plays a dominant role in driving the neoclassical tearing mode (NTM) instability in tokamak plasmas. In this work, we investigate the finite-banana-width (FBW) effect on the profile of ion bootstrap current in the island vicinity via an analytical approach. The results show that even if the pressure gradient vanishes inside the island, the ion bootstrap current can partly survive due to the FBW effect. The efficiency of the FBW effect is higher when the island width becomes smaller. Nevertheless, even when the island width is comparable to the ion FBW, the unperturbed ion bootstrap current inside the island cannot be largely recovered by the FBW effect, and thus the current loss still exists. This suggests that FBW effect alone cannot dramatically reduce the ion bootstrap current drive on NTMs.

A Review of Intelligent Driving Style Analysis Systems and Related Artificial Intelligence Algorithms

PubMed Central

Meiring, Gys Albertus Marthinus; Myburgh, Hermanus Carel

2015-01-01

In this paper the various driving style analysis solutions are investigated. An in-depth investigation is performed to identify the relevant machine learning and artificial intelligence algorithms utilised in current driver behaviour and driving style analysis systems. This review therefore serves as a trove of information, and will inform the specialist and the student regarding the current state of the art in driver style analysis systems, the application of these systems and the underlying artificial intelligence algorithms applied to these applications. The aim of the investigation is to evaluate the possibilities for unique driver identification utilizing the approaches identified in other driver behaviour studies. It was found that Fuzzy Logic inference systems, Hidden Markov Models and Support Vector Machines consist of promising capabilities to address unique driver identification algorithms if model complexity can be reduced. PMID:26690164

A Review of Intelligent Driving Style Analysis Systems and Related Artificial Intelligence Algorithms.

PubMed

Meiring, Gys Albertus Marthinus; Myburgh, Hermanus Carel

2015-12-04

In this paper the various driving style analysis solutions are investigated. An in-depth investigation is performed to identify the relevant machine learning and artificial intelligence algorithms utilised in current driver behaviour and driving style analysis systems. This review therefore serves as a trove of information, and will inform the specialist and the student regarding the current state of the art in driver style analysis systems, the application of these systems and the underlying artificial intelligence algorithms applied to these applications. The aim of the investigation is to evaluate the possibilities for unique driver identification utilizing the approaches identified in other driver behaviour studies. It was found that Fuzzy Logic inference systems, Hidden Markov Models and Support Vector Machines consist of promising capabilities to address unique driver identification algorithms if model complexity can be reduced.

Fuel magnetization without external field coils (AutoMag)

NASA Astrophysics Data System (ADS)

Slutz, Stephen; Jennings, Christopher; Awe, Thomas; Shipley, Gabe; Lamppa, Derek; McBride, Ryan

2016-10-01

Magnetized Liner Inertial Fusion (MagLIF) has produced fusion-relevant plasma conditions on the Z accelerator where the fuel was magnetized using external field coils. We present a novel concept that does not need external field coils. This concept (AutoMag) magnetizes the fuel during the early part of the drive current by using a composite liner with helical conduction paths separated by insulating material. The drive is designed so the current rises slowly enough to avoid electrical breakdown of the insulators until a sufficiently strong magnetic field is established. Then the current rises more quickly, which causes the insulators to break down allowing the drive current to follow an axial path and implode the liner. Low inductance magnetically insulated power feeds can be used with AutoMag to increase the drive current without interfering with diagnostic access. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Radially Focused Eddy Current Sensor for Detection of Longitudinal Flaws in Metallic Tubes

NASA Technical Reports Server (NTRS)

Wincheski, Russell A. (Inventor); Simpson, John W. (Inventor); Fulton, James P. (Inventor); Nath, Shridhar C. (Inventor); Todhunter, Ronald G. (Inventor); Namkung, Min (Inventor)

1999-01-01

A radially focused eddy current sensor detects longitudinal flaws in a metal tube. A drive coil induces eddy currents within the wall of the metal tube. A pick-up cod is spaced apart from the drive coil along the length of the metal tube. The pick@up coil is positioned with one end thereof lying adjacent the wall of the metal tube such that the pick-up coil's longitudinal axis is perpendicular to the wall of the metal tube. To isolate the pick-up coil from the magnetic flux of the drive coil and the flux from the induced eddy currents. except the eddy currents diverted by a longitudinal flaw. an electrically conducting material high in magnetic permeability surrounds all of the pick-up coil except its one end that is adjacent the walls of the metal tube. The electrically conducting material can extend into and through the drive coil in a coaxial relationship therewith.

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.

An Inverter Packaging Scheme for an Integrated Segmented Traction Drive System

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

Su, Gui-Jia; Tang, Lixin; Ayers, Curtis William

The standard voltage source inverter (VSI), widely used in electric vehicle/hybrid electric vehicle (EV/HEV) traction drives, requires a bulky dc bus capacitor to absorb the large switching ripple currents and prevent them from shortening the battery s life. The dc bus capacitor presents a significant barrier to meeting inverter cost, volume, and weight requirements for mass production of affordable EVs/HEVs. The large ripple currents become even more problematic for the film capacitors (the capacitor technology of choice for EVs/HEVs) in high temperature environments as their ripple current handling capability decreases rapidly with rising temperatures. It is shown in previous workmore » that segmenting the VSI based traction drive system can significantly decrease the ripple currents and thus the size of the dc bus capacitor. This paper presents an integrated packaging scheme to reduce the system cost of a segmented traction drive.« less

General Information: Chapman Conference on Magnetospheric Current Systems

NASA Technical Reports Server (NTRS)

Spicer, Daniel S.; Curtis, Steven

1999-01-01

The goal of this conference is to address recent achievements of observational, computational, theoretical, and modeling studies, and to foster communication among people working with different approaches. Electric current systems play an important role in the energetics of the magnetosphere. This conference will target outstanding issues related to magnetospheric current systems, placing its emphasis on interregional processes and driving mechanisms of current systems.

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.

How accurately do drivers evaluate their own driving behavior? An on-road observational study.

PubMed

Amado, Sonia; Arıkan, Elvan; Kaça, Gülin; Koyuncu, Mehmet; Turkan, B Nilay

2014-02-01

Self-assessment of driving skills became a noteworthy research subject in traffic psychology, since by knowing one's strenghts and weaknesses, drivers can take an efficient compensatory action to moderate risk and to ensure safety in hazardous environments. The current study aims to investigate drivers' self-conception of their own driving skills and behavior in relation to expert evaluations of their actual driving, by using naturalistic and systematic observation method during actual on-road driving session and to assess the different aspects of driving via comprehensive scales sensitive to different specific aspects of driving. 19-63 years old male participants (N=158) attended an on-road driving session lasting approximately 80min (45km). During the driving session, drivers' errors and violations were recorded by an expert observer. At the end of the driving session, observers completed the driver evaluation questionnaire, while drivers completed the driving self-evaluation questionnaire and Driver Behavior Questionnaire (DBQ). Low to moderate correlations between driver and observer evaluations of driving skills and behavior, mainly on errors and violations of speed and traffic lights was found. Furthermore, the robust finding that drivers evaluate their driving performance as better than the expert was replicated. Over-positive appraisal was higher among drivers with higher error/violation score and with the ones that were evaluated by the expert as "unsafe". We suggest that the traffic environment might be regulated by increasing feedback indicators of errors and violations, which in turn might increase the insight into driving performance. Improving self-awareness by training and feedback sessions might play a key role for reducing the probability of risk in their driving activity. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effects of fexofenadine and hydroxyzine on brake reaction time during car-driving with cellular phone use.

PubMed

Tashiro, Manabu; Horikawa, Etsuo; Mochizuki, Hideki; Sakurada, Yumiko; Kato, Motohisa; Inokuchi, Takatoshi; Ridout, Fran; Hindmarch, Ian; Yanai, Kazuhiko

2005-10-01

Antihistamines are a mainstay treatment for allergic rhinitis; however, many older agents cause adverse events, including sedation and central nervous system (CNS) impairment. Research has shown sedating effects of antihistamines on driving; currently, no known study has examined whether cellular phone usage while driving further compounds impairment in individuals administered antihistamines. The aim of this study was to examine this endpoint. In a randomized, double-blind, placebo-controlled, three-way crossover study, healthy volunteers received fexofenadine HCl 120 mg, hydroxyzine HCl 30 mg and placebo. Brake reaction time (BRT) was used to examine driving performance across four conditions: driving only; driving while completing simple calculations; complex calculations; and conversing on a cellular phone. Subjective sedation assessments were also conducted. Brake reaction time with and without cellular phone usage in fexofenadine-treated subjects did not differ significantly from placebo in any condition. In contrast, hydroxyzine-treated subjects were significantly more sedated and had slower BRTs, suggesting slower hazard recognition and brake application, compared with the fexofenadine and placebo groups in all conditions. Importantly, cellular phone operation was an additive factor, increasing BRTs in hydroxyzine-treated volunteers. Fexofenadine did not impair CNS function in subjects involved in a divided attention task of driving and cellular phone operation. Copyright (c) 2005 John Wiley & Sons, Ltd.

Using AORSA to simulate helicon waves in DIIID and ITER

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

Lau, Cornwall H; Jaeger, E. F.; Berry, Lee Alan

2014-01-01

Recent efforts by Vdovin [1] and Prater [2] have shown that helicon waves (fast waves at ~30 ion cyclotron frequency harmonic) may be an attractive option for driving efficient off-axis current drive during non-inductive tokamak operation for DIIID, ITER and DEMO. For DIIID scenarios, the ray tracing code GENRAY has been extensively used to study helicon current drive efficiency and location as a function many plasma parameters. has some limitations on absorption at high cyclotron harmonics, so the full wave code AORSA, which is applicable to arbitrary Larmor radius and can therefore resolve high ion cyclotron harmonics, has been recentlymore » used to validate the GENRAY model. It will be shown that the GENRAY and AORSA driven current drive profiles are comparable for the envisioned high temperature and density advanced scenarios for DIIID, where there is high single pass absorption due to electron Landau damping. AORSA results will be shown for various plasma parameters for DIIID and for ITER. Computational difficulties in achieving these AORSA results will also be discussed. * Work supported by USDOE Contract No. DE-AC05-00OR22725 [1] V. L. Vdovin, Plasma Physics Reports, V.39, No.2, 2013 [2] R. Prater et al, Nucl. Fusion, 52, 083024, 2014« less

Distraction produces over-additive increases in the degree to which alcohol impairs driving performance

PubMed Central

Van Dyke, Nicholas A.; Fillmore, Mark T.

2015-01-01

Rationale Research indicates that alcohol intoxication and increased demands on drivers’ attention from distractions (e.g. passengers and cell phones) contribute to poor driving performance and increased rates of traffic accidents and fatalities. Objectives The present study examined the separate and combined effects of alcohol and distraction on simulated driving performance at blood alcohol concentrations (BrACs) below the legal driving limit in the United States (i.e. 0.08%). Methods Fifty healthy adult drivers (36 men and 14 women) were tested in a driving simulator following a 0.65 g/kg dose of alcohol and a placebo. Drivers completed two drive tests; a distracted drive, which included a two-choice detection task, and an undistracted control drive. Multiple indicators of driving performance, such as drive speed, within-lane deviation, steering rate, and lane exceedances were measured. Results Alcohol and distraction each impaired measures of driving performance. Moreover, the magnitude of alcohol impairment was increased by at least two-fold when tested under the distracting versus the undistracted condition. Conclusions The findings highlight the need for a clearer understanding of how common distractions impact intoxicated drivers, especially at BrACs that are currently legal for driving in the United States. PMID:26349918

Name that tune: Mitigation of driver fatigue via a song naming game.

PubMed

Trumbo, Michael C; Jones, Aaron P; Robinson, Charles S H; Cole, Kerstan; Morrow, James D

2017-11-01

Fatigued driving contributes to a substantial number of motor vehicle accidents each year. Music listening is often employed as a countermeasure during driving in order to mitigate the effects of fatigue. Though music listening has been established as a distractor in the sense that it increases cognitive load during driving, it is possible that increased cognitive load is desirable under particular circumstances. For instance, during situations that typically result in cognitive underload, such as driving in a low-traffic monotonous stretch of highway, it may be beneficial for cognitive load to increase, thereby necessitating allocation of greater cognitive resources to the task of driving and attenuating fatigue. In the current study, we employed a song-naming game as a countermeasure to fatigued driving in a simulated monotonous environment. During the first driving session, we established that driving performance deteriorates in the absence of an intervention following 30min of simulated driving. During the second session, we found that a song-naming game employed at the point of fatigue onset was an effective countermeasure, as reflected by simulated driving performance that met or exceeded fresh driving behavior and was significantly better relative to fatigued performance during the first driving session. Copyright © 2017. Published by Elsevier Ltd.

Anomalous Ion Heating, Intrinsic and Induced Rotation in the Pegasus Toroidal Experiment

NASA Astrophysics Data System (ADS)

Burke, M. G.; Barr, J. L.; Bongard, M. W.; Fonck, R. J.; Hinson, E. T.; Perry, J. M.; Redd, A. J.; Thome, K. E.

2014-10-01

Pegasus plasmas are initiated through either standard, MHD stable, inductive current drive or non-solenoidal local helicity injection (LHI) current drive with strong reconnection activity, providing a rich environment to study ion dynamics. During LHI discharges, a large amount of anomalous impurity ion heating has been observed, with Ti ~ 800 eV but Te < 100 eV. The ion heating is hypothesized to be a result of large-scale magnetic reconnection activity, as the amount of heating scales with increasing fluctuation amplitude of the dominant, edge localized, n = 1 MHD mode. Chordal Ti spatial profiles indicate centrally peaked temperatures, suggesting a region of good confinement near the plasma core surrounded by a stochastic region. LHI plasmas are observed to rotate, perhaps due to an inward radial current generated by the stochastization of the plasma edge by the injected current streams. H-mode plasmas are initiated using a combination of high-field side fueling and Ohmic current drive. This regime shows a significant increase in rotation shear compared to L-mode plasmas. In addition, these plasmas have been observed to rotate in the counter-Ip direction without any external momentum sources. The intrinsic rotation direction is consistent with predictions from the saturated Ohmic confinement regime. Work supported by US DOE Grant DE-FG02-96ER54375.

The inductive, steady-state sustainment of stable spheromaks

NASA Astrophysics Data System (ADS)

Hossack, A. C.; Jarboe, T. R.; Morgan, K. D.; Sutherland, D. A.; Hansen, C. J.; Everson, C. J.; Penna, J. M.; Nelson, B. A.

2016-10-01

Inductive helicity injection current drive with imposed perturbations has led to the breakthrough of spheromak sustainment while maintaining stability. Sustained spheromaks show coherent, imposed plasma motion and low plasma-generated mode activity, indicating stability. Additionally, record current gain of 3.9 has been achieved with evidence of pressure confinement. The Helicity Injected Torus - Steady Inductive (HIT-SI) experiment studies efficient, steady-state current drive for magnetic confinement plasmas using a novel experimental method which is ideal for low aspect ratio, toroidal geometries and is compatible with closed flux surfaces. Analysis of surface magnetic probes indicates large n = 0 and 1 toroidal Fourier mode amplitudes and little energy in higher modes. Biorthogonal decomposition shows that almost all of the n = 1 energy is imposed by the injectors, rather than plasma-generated. Ion Doppler spectroscopy (IDS) measurements show coherent, imposed plasma motion of +/-2.5 cm in the region inside r 10 cm (a = 23 cm) and the size of the separate spheromak is consistent with that predicted by Imposed-dynamo Current Drive (IDCD). Coherent motion indicates that the spheromak is stable and a lack of plasma-generated n = 1 energy indicates that the maximum q is maintained below 1 for stability during sustainment.

Active lamp pulse driver circuit. [optical pumping of laser media

NASA Technical Reports Server (NTRS)

Logan, K. E. (Inventor)

1983-01-01

A flashlamp drive circuit is described which uses an unsaturated transistor as a current mode switch to periodically subject a partially ionized gaseous laser excitation flashlamp to a stable, rectangular pulse of current from an incomplete discharge of an energy storage capacitor. A monostable multivibrator sets the pulse interval, initiating the pulse in response to a flash command by providing a reference voltage to a non-inverting terminal of a base drive amplifier; a tap on an emitter resistor provides a feedback signal sensitive to the current amplitude to an inverting terminal of amplifier, thereby controlling the pulse amplitude. The circuit drives the flashlamp to provide a squarewave current flashlamp discharge.

Using music to change mood while driving.

PubMed

van der Zwaag, Marjolein D; Janssen, Joris H; Nass, Clifford; Westerink, Joyce H D M; Chowdhury, Shrestha; de Waard, Dick

2013-01-01

This study investigated whether gradual or abrupt music change towards more calming music is most effective in calming drivers during high-demand driving situations. Twenty-eight participants were subjected to two types of music change (gradual, abrupt) in a within-subject design. First, a relatively happy mood was induced with personally selected music during an eight-minute simulated high-demand drive. The drive then continued and the mood was changed either gradually or abruptly. Subjective results showed successful music mood induction irrespective of gradual or abrupt changes. The results further showed lower skin conductance (less arousal) and more facial corrugator muscle tension (more sadness) during the abrupt music change. Fewer accidents occurred during the abrupt music mood change. To conclude, the results support the abrupt way of changing music type to down-regulate one's mood: during high-demand driving, abrupt changes in music led to more physiological calmness and improved driving performance, and were thus safer and more effective. The current study shows that during high-demand drives, drivers are calmed more effectively using abrupt music changes compared to gradual music changes. This is illustrated by reductions in physiological arousal and improved driving behaviour. Hence, in-car music presentation can be used as a tool to improve driver's mood and behaviour.

Highly stable field emission from ZnO nanowire field emitters controlled by an amorphous indium–gallium–zinc-oxide thin film transistor

NASA Astrophysics Data System (ADS)

Li, Xiaojie; Wang, Ying; Zhang, Zhipeng; Ou, Hai; She, Juncong; Deng, Shaozhi; Xu, Ningsheng; Chen, Jun

2018-04-01

Lowering the driving voltage and improving the stability of nanowire field emitters are essential for them to be applied in devices. In this study the characteristics of zinc oxide (ZnO) nanowire field emitter arrays (FEAs) controlled by an amorphous indium–gallium–zinc-oxide thin film transistor (a-IGZO TFT) were studied. A low driving voltage along with stabilization of the field emission current were achieved. Modulation of field emission currents up to three orders of magnitude was achieved at a gate voltage of 0–32 V for a constant anode voltage. Additionally, a-IGZO TFT control can dramatically reduce the emission current fluctuation (i.e., from 46.11 to 1.79% at an emission current of ∼3.7 µA). Both the a-IGZO TFT and ZnO nanowire FEAs were prepared on glass substrates in our research, demonstrating the feasibility of realizing large area a-IGZO TFT-controlled ZnO nanowire FEAs.

Photometric and Colorimetric Assessment of LED Chip Scale Packages by Using a Step-Stress Accelerated Degradation Test (SSADT) Method.

PubMed

Qian, Cheng; Fan, Jiajie; Fang, Jiayi; Yu, Chaohua; Ren, Yi; Fan, Xuejun; Zhang, Guoqi

2017-10-16

By solving the problem of very long test time on reliability qualification for Light-emitting Diode (LED) products, the accelerated degradation test with a thermal overstress at a proper range is regarded as a promising and effective approach. For a comprehensive survey of the application of step-stress accelerated degradation test (SSADT) in LEDs, the thermal, photometric, and colorimetric properties of two types of LED chip scale packages (CSPs), i.e., 4000 °K and 5000 °K samples each of which was driven by two different levels of currents (i.e., 120 mA and 350 mA, respectively), were investigated under an increasing temperature from 55 °C to 150 °C and a systemic study of driving current effect on the SSADT results were also reported in this paper. During SSADT, junction temperatures of the test samples have a positive relationship with their driving currents. However, the temperature-voltage curve, which represents the thermal resistance property of the test samples, does not show significant variance as long as the driving current is no more than the sample's rated current. But when the test sample is tested under an overdrive current, its temperature-voltage curve is observed as obviously shifted to the left when compared to that before SSADT. Similar overdrive current affected the degradation scenario is also found in the attenuation of Spectral Power Distributions (SPDs) of the test samples. As used in the reliability qualification, SSADT provides explicit scenes on color shift and correlated color temperature (CCT) depreciation of the test samples, but not on lumen maintenance depreciation. It is also proved that the varying rates of the color shift and CCT depreciation failures can be effectively accelerated with an increase of the driving current, for instance, from 120 mA to 350 mA. For these reasons, SSADT is considered as a suitable accelerated test method for qualifying these two failure modes of LED CSPs.

Photometric and Colorimetric Assessment of LED Chip Scale Packages by Using a Step-Stress Accelerated Degradation Test (SSADT) Method

PubMed Central

Yu, Chaohua; Fan, Xuejun; Zhang, Guoqi

2017-01-01

By solving the problem of very long test time on reliability qualification for Light-emitting Diode (LED) products, the accelerated degradation test with a thermal overstress at a proper range is regarded as a promising and effective approach. For a comprehensive survey of the application of step-stress accelerated degradation test (SSADT) in LEDs, the thermal, photometric, and colorimetric properties of two types of LED chip scale packages (CSPs), i.e., 4000 °K and 5000 °K samples each of which was driven by two different levels of currents (i.e., 120 mA and 350 mA, respectively), were investigated under an increasing temperature from 55 °C to 150 °C and a systemic study of driving current effect on the SSADT results were also reported in this paper. During SSADT, junction temperatures of the test samples have a positive relationship with their driving currents. However, the temperature-voltage curve, which represents the thermal resistance property of the test samples, does not show significant variance as long as the driving current is no more than the sample’s rated current. But when the test sample is tested under an overdrive current, its temperature-voltage curve is observed as obviously shifted to the left when compared to that before SSADT. Similar overdrive current affected the degradation scenario is also found in the attenuation of Spectral Power Distributions (SPDs) of the test samples. As used in the reliability qualification, SSADT provides explicit scenes on color shift and correlated color temperature (CCT) depreciation of the test samples, but not on lumen maintenance depreciation. It is also proved that the varying rates of the color shift and CCT depreciation failures can be effectively accelerated with an increase of the driving current, for instance, from 120 mA to 350 mA. For these reasons, SSADT is considered as a suitable accelerated test method for qualifying these two failure modes of LED CSPs. PMID:29035300

Simulated Driving Performance of Adults with ADHD: Comparisons with Alcohol Intoxication

PubMed Central

Weafer, Jessica; Camarillo, Daniel; Fillmore, Mark T.; Milich, Richard; Marczinski, Cecile A.

2015-01-01

Previous research has demonstrated that adults with ADHD are more likely to experience driving-related problems, which suggests that they may exhibit poorer driving performance. However, direct experimental evidence of this hypothesis is limited. The current study involved two experiments that evaluated driving performance in adults with ADHD in terms of the types of driving decrements typically associated with alcohol intoxication. Experiment 1 compared the simulated driving performance of 15 adults with ADHD to 23 adult control participants, who performed the task both while sober and intoxicated. Results showed that sober adults with ADHD exhibited decrements in driving performance compared to sober controls, and that the profile of impairment for the sober ADHD group did in fact resemble that of intoxicated drivers at the BAC level for legally impaired driving in the United States. Driving impairment of the intoxicated individuals was characterized by greater deviation of lane position, faster and more abrupt steering maneuvers, and increased speed variability. Experiment 2 was a dose-challenge study in which 8 adults with ADHD and 8 controls performed the driving simulation task under three doses of alcohol: 0.65 g/kg, 0.45 g/kg, and 0.0 g/kg (placebo). Results showed that driving performance in both groups was impaired in response to alcohol, and that individuals with ADHD exhibited generally poorer driving performance than did controls across all dose conditions. Together the findings provide compelling evidence to suggest that the cognitive and behavioral deficits associated with ADHD might impair driving performance in such a manner as to resemble that of an alcohol intoxicated driver. Moreover, alcohol might impair the performance of drivers with ADHD in an additive fashion that could considerably compromise their driving skill even at blood alcohol concentrations below the legal limit. PMID:18540785

The analysis of the quality of the frequency control of induction motor carried out on the basis of the processes in the rotor circuit

NASA Astrophysics Data System (ADS)

Kodkin, V. L.; Anikin, A. S.; Baldenkov, A. A.

2018-01-01

The results of researches of asynchronous electric drives with the frequency control which are carried out for the purpose of establishment of causes and effect relationships between a control method, the implementable standard frequency converter of the Schneider Electric company (ATV-71, ATV-32) and its efficiency are given in article. Tests with asynchronous motors with wound rotor were for the first time carried out. It allowed registering during the experiments the instantaneous values not only the stator currents, but also rotor currents. Authors for the first time applied spectrum analysis of stator and rotor currents, it showed that «sensorless vector» control leads to origin of high-frequency harmonicas with the considerable amplitude and, as a result of they are non-sinusoidal of the created torque and inefficiency of the electric drive. The accelerations that are carried out during the researches to 94, 157 and 251 Rad/s confirmed this feature of vector control that appears incapable to linearize the asynchronous electric drive as it was supposed authors of a method. These results do not contradict theoretical provisions if not to neglect assumptions which usually become in case of an output of the equations of vector control. Unfortunately, the modern researchers do not subject these assumptions to doubts. Continued studies make it possible to create an effective frequency management of asynchronous electric drives required for current technology.

Neoclassical Current Drive by Waves with a Symmetric Spectrum

NASA Astrophysics Data System (ADS)

Helander, Per

2000-10-01

It is well known that plasma waves can produce electric currents if the waves have an asymmetric spectrum, so that they either interact preferentially with electrons travelling in one direction along the magnetic field or impart net parallel momentum to the electrons [1]. This directionality creates an asymmetry in the electron distribution function and thereby produces a current parallel to the field. We demonstrate, somewhat surprisingly, that in a plasma confined by a curved magnetic field no such spectral asymmetry is necessary for current drive if the effect of collisions is properly taken into account. For instance, in a toroidal plasma a current can be produced by a spectrally symmetric wave field if this field is instead up-down asymmetric, which is frequently the case for electron cyclotron current drive (ECCD) in tokamaks. We have calculated the resulting current drive efficiency and found it to be smaller than that of the conventional current drive mechanism in the banana regime, but not insignificant in the plateau regime. The results will be compared with experiments in DIII-D, where the measured efficiency exceeds the classical prediction [2]. Our calculations are focused on this case of ECCD in tokamaks, but the basic physical mechanism is much more general. It is of a universal neoclassical nature and applies to all wave-particle interaction in curved magnetic fields. [1] N.J. Fisch, Rev. Mod. Phys. 59, 175 (1987). [2] Y. R. Lin-Liu et al., 26th EPS Conf. on Contr. Fusion and Plasma Phys.(European Phys. Soc. Paris, 1999) Vol. 23J, p 1245.

Derivation of dynamo current drive in a closed-current volume and stable current sustainment in the HIT-SI experiment

DOE PAGES

Hossack, A. C.; Sutherland, D. A.; Jarboe, T. R.

2017-02-01

A derivation is given showing that the current inside a closed-current volume can be sustained against resistive dissipation by appropriately phased magnetic perturbations. Imposed-dynamo current drive (IDCD) theory is used to predict the toroidal current evolution in the HIT-SI experiment as a function of magnetic fluctuations at the edge. Analysis of magnetic fields from a HIT-SI discharge shows that the injector-imposed fluctuations are sufficient to sustain the measured toroidal current without instabilities whereas the small, plasma-generated magnetic fluctuations are not sufficiently large to sustain the current.

Derivation of dynamo current drive in a closed-current volume and stable current sustainment in the HIT-SI experiment

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

Hossack, A. C.; Sutherland, D. A.; Jarboe, T. R.

A derivation is given showing that the current inside a closed-current volume can be sustained against resistive dissipation by appropriately phased magnetic perturbations. Imposed-dynamo current drive (IDCD) theory is used to predict the toroidal current evolution in the HIT-SI experiment as a function of magnetic fluctuations at the edge. Analysis of magnetic fields from a HIT-SI discharge shows that the injector-imposed fluctuations are sufficient to sustain the measured toroidal current without instabilities whereas the small, plasma-generated magnetic fluctuations are not sufficiently large to sustain the current.

Direct and indirect effects of impulsivity traits on drinking and driving in young adults.

PubMed

Treloar, Hayley R; Morris, David H; Pedersen, Sarah L; McCarthy, Denis M

2012-09-01

Impulsivity is strongly associated with alcohol-related risk-taking behavior, and this association has been found to be mediated by alcohol cognitions. The current study expanded this literature by comparing the relative association of distinct impulsivity traits with a specific risky behavior--drinking and driving. We then tested whether drinking-and-driving expectancies uniquely mediated this relation over and above other cognitions about alcohol and drinking and driving. College student drivers (n = 816; 53.6% women) completed a paper-and-pencil survey in small groups. Self-report measures assessed alcohol use, impulsivity traits, alcohol expectancies, drinking-and-driving cognitions (i.e., expectancies, attitudes, beliefs), and drinking and driving. Although all impulsivity traits were correlated with drinking and driving, only urgency uniquely contributed to drinking and driving. Indirect effect tests indicated that drinking-and-driving convenience expectancies partially mediated this association as well as that between (lack of) perseverance and drinking and driving. These results remained significant after controlling for alcohol expectancies and other drinking-and-driving cognitions. These findings highlight the importance of distinguishing among impulsivity traits to improve theoretical models of the processes by which personality leads to specific alcohol-related consequences. In addition, results extend previous research by providing evidence for the unique importance of expectancies regarding the convenience of drinking and driving over and above more global alcohol expectancies and other drinking-and-driving cognitions.

Self-rated driving habits among older adults with clinically-defined mild cognitive impairment, clinically-defined dementia, and normal cognition.

PubMed

O'Connor, Melissa L; Edwards, Jerri D; Bannon, Yvonne

2013-12-01

Older adults with clinically-defined dementia may report reducing their driving more than cognitively normal controls. However, it is unclear how these groups compare to individuals with clinically-defined mild cognitive impairment (MCI) in terms of driving behaviors. The current study investigated self-reported driving habits among adults age 60 and older with clinical MCI (n=41), clinical mild dementia (n=40), and normal cognition (n=43). Participants reported their driving status, driving frequency (days per week), and how often they avoided accessing the community, making left turns, driving at night, driving in unfamiliar areas, driving on high-traffic roads, and driving in bad weather. After adjusting for education, a MANCOVA revealed that participants with MCI and dementia avoided unfamiliar areas and high-traffic roads significantly more than normal participants. Participants with dementia also avoided left turns and accessing the community more than those with normal cognition and MCI (p<0.05 for all). The other driving variables did not significantly differ between groups. Thus, older adults with clinically-defined MCI, as well as those with dementia, avoided some complex driving situations more than cognitively intact adults. However, all diagnostic groups had similar rates of driving cessation and frequency. Future research should examine the safety implications of such findings. Copyright © 2013 Elsevier Ltd. All rights reserved.

The effect of billboard design specifications on driving: A pilot study.

PubMed

Marciano, Hadas; Setter, Pe'erly

2017-07-01

Decades of research on the effects of advertising billboards on road accident rates, driver performance, and driver visual scanning behavior, has produced no conclusive findings. We suggest that road safety researchers should shift their focus and attempt to identify the billboard characteristics that are most distracting to drivers. This line of research may produce concrete guidelines for permissible billboards that would be likely to reduce the influence of the billboards on road safety. The current study is a first step towards this end. A pool of 161 photos of real advertising billboards was used as stimuli within a triple task paradigm designed to simulate certain components of driving. Each trial consisted of one ongoing tracking task accompanied by two additional concurrent tasks: (1) billboard observation task; and (2) circle color change identification task. Five clusters of billboards, identified by conducting a cluster analysis of their graphic content, were used as a within variable in one-way ANOVAs conducted on performance level data collected from the multiple tasks. Cluster 5, labeled Loaded Billboards, yielded significantly deteriorated performance on the tracking task. Cluster 4, labeled Graphical Billboards, yielded deteriorated performance primarily on the color change identification task. Cluster 3, labeled Minimal Billboards, had no effect on any of these tasks. We strongly recommend that these clusters be systematically explored in experiments involving additional real driving settings, such as driving simulators and field studies. This will enable validation of the current results and help incorporate them into real driving situations. Copyright © 2017. Published by Elsevier Ltd.

100-car naturalistic study

DOT National Transportation Integrated Search

2005-06-01

The 100-Car Naturalistic Driving Study was undertaken with the goal of obtaining data on driver performance and behavior in the moments leading up to a crash. The results of the current study in conjunction with Hanowski, Keisler, and Wierwille (2004...

Application of drive circuit based on L298N in direct current motor speed control system

NASA Astrophysics Data System (ADS)

Yin, Liuliu; Wang, Fang; Han, Sen; Li, Yuchen; Sun, Hao; Lu, Qingjie; Yang, Cheng; Wang, Quanzhao

2016-10-01

In the experiment of researching the nanometer laser interferometer, our design of laser interferometer circuit system is up to the wireless communication technique of the 802.15.4 IEEE standard, and we use the RF TI provided by Basic to receive the data on speed control system software. The system's hardware is connected with control module and the DC motor. However, in the experiment, we found that single chip microcomputer control module is very difficult to drive the DC motor directly. The reason is that the DC motor's starting and braking current is larger than the causing current of the single chip microcomputer control module. In order to solve this problem, we add a driving module that control board can transmit PWM wave signal through I/O port to drive the DC motor, the driving circuit board can come true the function of the DC motor's positive and reversal rotation and speed adjustment. In many various driving module, the L298N module's integrated level is higher compared with other driver module. The L298N model is easy to control, it not only can control the DC motor, but also achieve motor speed control by modulating PWM wave that the control panel output. It also has the over-current protection function, when the motor lock, the L298N model can protect circuit and motor. So we use the driver module based on L298N to drive the DC motor. It is concluded that the L298N driver circuit module plays a very important role in the process of driving the DC motor in the DC motor speed control system.

Study on compensation algorithm of head skew in hard disk drives

NASA Astrophysics Data System (ADS)

Xiao, Yong; Ge, Xiaoyu; Sun, Jingna; Wang, Xiaoyan

2011-10-01

In hard disk drives (HDDs), head skew among multiple heads is pre-calibrated during manufacturing process. In real applications with high capacity of storage, the head stack may be tilted due to environmental change, resulting in additional head skew errors from outer diameter (OD) to inner diameter (ID). In case these errors are below the preset threshold for power on recalibration, the current strategy may not be aware, and drive performance under severe environment will be degraded. In this paper, in-the-field compensation of small DC head skew variation across stroke is proposed, where a zone table has been equipped. Test results demonstrating its effectiveness to reduce observer error and to enhance drive performance via accurate prediction of DC head skew are provided.

Punchets: nonlinear transport in Hamiltonian pump-ratchet hybrids

NASA Astrophysics Data System (ADS)

Dittrich, Thomas; Medina Sánchez, Nicolás

2018-02-01

‘Punchets’ are hybrids between ratchets and pumps, combining a spatially periodic static potential, typically asymmetric under space inversion, with a local driving that breaks time-reversal invariance, and are intended to model metal or semiconductor surfaces irradiated by a collimated laser beam. Their crucial feature is irregular driven scattering between asymptotic regions supporting periodic (as opposed to free) motion. With all binary spatio-temporal symmetries broken, scattering in punchets typically generates directed currents. We here study the underlying nonlinear transport mechanisms, from chaotic scattering to the parameter dependence of the currents, in three types of Hamiltonian models, (i) with spatially periodic potentials where only in the driven scattering region, spatial and temporal symmetries are broken, and (ii), spatially asymmetric (ratchet) potentials with a driving that only breaks time-reversal invariance. As more realistic models of laser-irradiated surfaces, we consider (iii), a driving in the form of a running wave confined to a compact region by a static envelope. In this case, the induced current can even run against the direction of wave propagation, drastically evidencing its nonlinear nature. Quantizing punchets is indicated as a viable research perspective.

Polar Radiation-Flux Symmetry Measurements in Z-Pinch-Driven Hohlraums with Symmetric Double-Pinch Drive

NASA Astrophysics Data System (ADS)

Hanson, D. L.; Vesey, R. A.; Cuneo Porter, M. E., Jr.; Chandler, G. A.; Ruggles, L. E.; Simpson, W. W.; Seamen, H.; Primm, P.; Torres, J.; McGurn, J.; Gilliland, T. L.; Reynolds, P.; Hebron, D. E.; Dropinski, S. C.; Schroen-Carey, D. G.; Hammer, J. H.; Landen, O.; Koch, J.

2000-10-01

We are currently exploring symmetry requirements of the z-pinch-driven hohlraum concept [1] for high-yield inertial confinement fusion. In experiments on the Z accelerator, the burnthrough of a low-density self-backlit foam ball has been used to diagnose the large time-dependent flux asymmetry of several single-sided-drive hohlraum geometries [2]. We are currently applying this technique to study polar radiation flux symmetry in a symmetric double z-pinch geometry. Wire arrays on opposite ends of the hohlraum, connected in series to a single current drive of 18 MA, implode and stagnate on axis, efficiently radiating about 100 TW of x rays which heat the secondary to 75 eV. Comparisons with 3-D radiosity and 2-D rad-hydro models of hohlraum symmetry performance will be presented. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under Contract DE-AC04-94AL85000. 1 J. H. Hammer et al., Phys. Plasmas 6, 2129 (1999). 2 D. L. Hanson et al., Bull. Am. Phys. Soc. 44, 40 (1999).

Constructing a publically available distracted driving database and research tool.

PubMed

Atchley, Paul; Tran, Ashleigh V; Salehinejad, Mohammad Ali

2017-02-01

The goal of the current work was to create a publicly available visualization tool of distracted driving research, the purpose of which is to allow the public and other stakeholders to empirically inform questions of their choice that may bear on policy discussions. Fifty years of distracted driving research was used to design a comprehensive database of studies that evaluated the effects of distraction on driving performance. Distraction sources (e.g., texting, talking, visual distraction) and performance measures were defined, and the sample of studies were evaluated and categorized by their measures. The final product yielded 342 studies using various methodologies. Across all measures, 1297 found distractions degraded driving performance, 54 found distraction improved driving performance, and 257 found distraction had no effect on driving performance. An analysis of the most common phone distractions (texting and talking) showed that texting almost always results in degraded performance. Aggregate data reveal no difference in performance decrements for hand-held or hands-free phones even though single studies of those variables vary in their outcomes. This project illustrates how scientific research can be made publically available for use by a diverse audience of stakeholders. An important result of this project is that data aggregated along a simple set of characteristics such as whether or not performance is decreased, improved or not affected, can reveal trends in the data that are less clear from any individual study. Copyright © 2016 Elsevier Ltd. All rights reserved.

Study on Use of Fuel-Cell Auxiliary Power Units in Refrigerator Cars Employed for Delivery to Convenience Store

NASA Astrophysics Data System (ADS)

Katayama, Noboru; Kamiyama, Hideyuki; Kogoshi, Sumio; Kudo, Yusuke; Fukada, Takafumi; Ogawa, Makoto

The use of fuel-cell auxiliary power units (FC-APU) in refrigerator cars employed delivery to for convenience store delivery has been studied. The delivery pattern is assumed to be a typical pattern that includes driving between convenience stores or between a delivery center and a convenience store, unloading, driver's lunch break. The M15 driving mode, which simulates the driving condition in urban areas, is used as the driving mode in the delivery pattern. The FC-APU system includes a proton-exchange membrane fuel cell (PEFC) module, an inverter, and DC/DC converter. Bench tests of the FC-APU are performed to determine the hydrogen fuel consumption rate and the energy efficiency; these values depend on the output power of the PEFC module. The calculated relationship between the output power and fuel consumption rate of a current used system, which consists of an alternator and a secondary battery, are used to estimate the energy efficiency of the current used system. On the basis of the measurement data in this study and the results for the model proposed by Brodric et al. [C. J. Brodrick et al., Trans. Res. D, vol 7, pp. 303 (2002)], the payback period is calculated. The results indicate that the payback period would be 2.1 years when the FC-APU operates at a load of 70%.

Relationship of aggression, negative affect, substance use problems, and childhood delinquency to DWI recidivism.

PubMed

Linn, Braden K; Nochajski, Thomas; Wieczorek, William

2016-01-01

Driving under the influence remains a pervasive problem. Approximately 30% of those arrested for impaired driving offenses each year are repeat offenders, suggesting that current rehabilitative efforts are not sufficiently effective for reducing driving while intoxicated (DWI) recidivism. Aggression, negative affect, substance use problems, and childhood delinquency have been noted in the population of impaired drivers, but study of these variables on recidivism has been limited. The aim of the current study was to examine the effects of aggression, negative affect, substance use problems, and childhood delinquency on DWI recidivism among first time offenders. In 1992, 6436 individuals in impaired driver programs in New York State were surveyed. A total of 3511 individuals provided names so that state driver abstracts could be reviewed in the future. A total of 2043 matches were found and 1770 remained after excluding those with previous DWI convictions. Driver records were reviewed in 2010 and 2012, providing between 18 and 20 years of follow-up. During the follow-up period, 16.5% of individuals were arrested for an impaired driving offense. Multivariate analysis suggested that recidivism was a function of several problems, including: alcohol problem severity, aggression, negative affect, drug problem severity, criminal history, and childhood delinquency. Impaired driving programs should assess for childhood delinquency, aggressive tendencies, and negative affect as these constructs, along with substance use, are evident among impaired drivers who recidivate. Interventions addressing aggression and negative affect may ultimately prove useful in reducing recidivism.

Fivefold confinement time increase in the Madison Symmetric Torus using inductive poloidal current drive

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

Stoneking, M.R.; Lanier, N.E.; Prager, S.C.

1996-12-01

Current profile control is employed in the Madison Symmetric Torus reversed field pinch to reduce the magnetic fluctuations responsible for anomalous transport. An inductive poloidal electric field pulse is applied in the sense to flatten the parallel current profile, reducing the dynamo fluctuation amplitude required to sustain the equilibrium. This technique demonstrates a substantial reduction in fluctuation amplitude (as much as 50%), and improvement in energy confinement (from 1 ms to 5 ms); a record low fluctuation (0.8%) and record high temperature (615 eV) for this device were observed simultaneously during current drive experiments. Plasma beta increases by 50% andmore » the Ohmic input power is three times lower. Particle confinement improves and plasma impurity contamination is reduced. The results of the transient current drive experiments provide motivation for continuing development of steady-state current profile control strategies for the reversed field pinch.« less

Electron Cyclotron Radiation, Related Power Loss, and Passive Current Drive in Tokamaks: A Review

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

Fidone, Ignazio; Giruzzi, Gerardo; Granata, Giovanni

2001-01-15

A critical review on emission of weakly damped, high-harmonics electron cyclotron radiation, the related synchrotron power loss, and passive current drive in tokamaks with a fish-scale first wall is presented. First, the properties of overlapping harmonics are discussed using general analytical formulas and numerical applications. Next, the radiation power loss and efficiency of passive current drive in tokamak reactors are derived for the asymmetric fish-scale first wall. The radiation power loss is determined by the direction-averaged reflection coefficient {sigma}{sub 0} and the passive current drive by the differential reflectivity {delta}{sigma}/(1 - {sigma}{sub 0}). Finally, the problem of experimental investigations ofmore » the high harmonics radiation spectra, of {sigma}{sub 0} and {delta}{sigma}/(1 - {sigma}{sub 0}) in existing and next-step tokamaks, is discussed. Accurate measurements of the radiation spectra and the fish-scale reflectivity can be performed at arbitrary electron temperature using a partial fish-scale structure located near the tokamak equatorial plane.« less

Restraining for switching effects in an AC driving pixel circuit of the OLED-on-silicon

NASA Astrophysics Data System (ADS)

Liu, Yan-Yan; Geng, Wei-Dong; Dai, Yong-Ping

2010-03-01

The AC driving scheme for OLEDs, which uses the pixel circuit with two transistors and one capacitor (2T1C), can extend the lifetime of the active matrix organic light-emitting diode (AMOLED) on silicon, but there are switching effects during the switch of AC signals, which result in the voltage variation on the storage capacitor and cause the current glitch in OLED. That would decrease the gray scale of the OLED. This paper proposes a novel pixel circuit consisting of three transistors and one capacitor to realize AC driving for the OLED-on-silicon while restraining the switching effects. Simulation results indicate that the proposed circuit is less sensitive to switching effects. Also, another pixel circuit is proposed to further reduce the driving current to meet the current constraints for the OLED-on-silicon.

Deducing noninductive current profile from surface voltage evolution

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

Litwin, C.; Wukitch, S.; Hershkowitz, N.

Solving the resistive diffusion equation in the presence of a noninductive current source determines the time-evolution of the surface voltage. By inverting the problem the current drive profile can be determined from the surface voltage evolution. We show that under wide range of conditions the deduced profile is unique. If the conductivity profile is known, this method can be employed to infer the noninductive current profile, and, ipso facto, the profile of the total current. We discuss the application of this method to analyze the Alfven wave current drive experiments in Phaedrus-T.

Driving Cessation and Dementia: Results of the Prospective Registry on Dementia in Austria (PRODEM)

PubMed Central

Seiler, Stephan; Schmidt, Helena; Lechner, Anita; Benke, Thomas; Sanin, Guenter; Ransmayr, Gerhard; Lehner, Riccarda; Dal-Bianco, Peter; Santer, Peter; Linortner, Patricia; Eggers, Christian; Haider, Bernhard; Uranues, Margarete; Marksteiner, Josef; Leblhuber, Friedrich; Kapeller, Peter; Bancher, Christian; Schmidt, Reinhold

2012-01-01

Objective To assess the influence of cognitive, functional and behavioral factors, co-morbidities as well as caregiver characteristics on driving cessation in dementia patients. Methods The study cohort consists of those 240 dementia cases of the ongoing prospective registry on dementia in Austria (PRODEM) who were former or current car-drivers (mean age 74.2 (±8.8) years, 39.6% females, 80.8% Alzheimer’s disease). Reasons for driving cessation were assessed with the patients’ caregivers. Standardized questionnaires were used to evaluate patient- and caregiver characteristics. Cognitive functioning was determined by Mini-Mental State Examination (MMSE), the CERAD neuropsychological test battery and Clinical Dementia Rating (CDR), activities of daily living (ADL) by the Disability Assessment for Dementia, behavior by the Neuropsychiatric Inventory (NPI) and caregiver burden by the Zarit burden scale. Results Among subjects who had ceased driving, 136 (93.8%) did so because of “Unacceptable risk” according to caregiver’s judgment. Car accidents and revocation of the driving license were responsible in 8 (5.5%) and 1(0.7%) participant, respectively. Female gender (OR 5.057; 95%CI 1.803–14.180; p = 0.002), constructional abilities (OR 0.611; 95%CI 0.445–0.839; p = 0.002) and impairment in Activities of Daily Living (OR 0.941; 95%CI 0.911–0.973; p<0.001) were the only significant and independent associates of driving cessation. In multivariate analysis none of the currently proposed screening tools for assessment of fitness to drive in elderly subjects including the MMSE and CDR were significantly associated with driving cessation. Conclusion The risk-estimate of caregivers, but not car accidents or revocation of the driving license determines if dementia patients cease driving. Female gender and increasing impairment in constructional abilities and ADL raise the probability for driving cessation. If any of these factors also relates to undesired traffic situations needs to be determined before recommendations for their inclusion into practice parameters for the assessment of driving abilities in the elderly can be derived from our data. PMID:23300746

Simulation of Trolleybus Traction Induction Drive With Supercapacitor Energy Storage System

NASA Astrophysics Data System (ADS)

Brazis, V.; Latkovskis, L.; Grigans, L.

2010-01-01

The article considers the possibilities of saving the regenerative braking energy in Škoda 24Tr type trolleybuses by installing the onboard supercapacitor energy storage system (ESS) and improving its performance with automated switching to the autonomous traction mode. Proposed is an ESS control system with constant DC bus voltage in the supercapacitor charging mode and supercapacitor current proportional to the AC drive current in the discharging mode. The authors investigate stability of the trolleybus ESS control system operating together with AC traction drive in various overhead voltage failure modes. The co-simulation of ESS operation was done by Matlab/Simulink AC drive and PSIM ESS continuous models.

Integral Sensor Fault Detection and Isolation for Railway Traction Drive.

PubMed

Garramiola, Fernando; Del Olmo, Jon; Poza, Javier; Madina, Patxi; Almandoz, Gaizka

2018-05-13

Due to the increasing importance of reliability and availability of electric traction drives in Railway applications, early detection of faults has become an important key for Railway traction drive manufacturers. Sensor faults are important sources of failures. Among the different fault diagnosis approaches, in this article an integral diagnosis strategy for sensors in traction drives is presented. Such strategy is composed of an observer-based approach for direct current (DC)-link voltage and catenary current sensors, a frequency analysis approach for motor current phase sensors and a hardware redundancy solution for speed sensors. None of them requires any hardware change requirement in the actual traction drive. All the fault detection and isolation approaches have been validated in a Hardware-in-the-loop platform comprising a Real Time Simulator and a commercial Traction Control Unit for a tram. In comparison to safety-critical systems in Aerospace applications, Railway applications do not need instantaneous detection, and the diagnosis is validated in a short time period for reliable decision. Combining the different approaches and existing hardware redundancy, an integral fault diagnosis solution is provided, to detect and isolate faults in all the sensors installed in the traction drive.

Integral Sensor Fault Detection and Isolation for Railway Traction Drive

PubMed Central

del Olmo, Jon; Poza, Javier; Madina, Patxi; Almandoz, Gaizka

2018-01-01

Due to the increasing importance of reliability and availability of electric traction drives in Railway applications, early detection of faults has become an important key for Railway traction drive manufacturers. Sensor faults are important sources of failures. Among the different fault diagnosis approaches, in this article an integral diagnosis strategy for sensors in traction drives is presented. Such strategy is composed of an observer-based approach for direct current (DC)-link voltage and catenary current sensors, a frequency analysis approach for motor current phase sensors and a hardware redundancy solution for speed sensors. None of them requires any hardware change requirement in the actual traction drive. All the fault detection and isolation approaches have been validated in a Hardware-in-the-loop platform comprising a Real Time Simulator and a commercial Traction Control Unit for a tram. In comparison to safety-critical systems in Aerospace applications, Railway applications do not need instantaneous detection, and the diagnosis is validated in a short time period for reliable decision. Combining the different approaches and existing hardware redundancy, an integral fault diagnosis solution is provided, to detect and isolate faults in all the sensors installed in the traction drive. PMID:29757251

Diplopia and driving: a problematic issue.

PubMed

Righi, Stefano; Boffano, Paolo; Guglielmi, Valeria; Rossi, Paolo; Martorina, Massimo

2014-10-01

The aim of this article was to review the literature regarding diplopia and driving license and to review the West European legislations about this topic, in order to obtain appropriate indications for hospitals specialists and patients. A systematic review of articles published about diplopia and driving was performed. In addition a review of West European national legislations about driving license regulations for medical illnesses was performed, in addition to the European Union Directive on driving licenses. In the literature, the presence of diplopia has not been considered a reliable predictor of the safety of driving behavior, or it has not appeared to be a contraindication for driving according to some authors who were unable to demonstrate significant differences on driving simulator performance between subjects with chronic stable diplopia and control subjects. Nevertheless, in all western European legislations, acute diplopia constitutes an important limitation for driving, thus making the knowledge of current regulations fundamental for specialists involved in managing patients with diplopia. Ophthalmologists and maxillofacial/head and neck surgeons, may advise patients before hospital discharge about current legislations in their respective countries. Copyright © 2014 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Relativistic theory of radiofrequency current drive

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

Balescu, R.; Metens, T.

1991-05-01

A fully relativistic kinetic theory of rf current drive in a tokamak is developed for both the lower hybrid and the electron cyclotron mechanisms. The problem is treated as a generalization of the classical transport equations, in which the thermodynamic forces are modified by the addition of a rf-source term. In the limit of weak rf amplitude and neglecting toroidal effects (such as particle trapping), explicit analytical expressions are obtained for the rf-generated current, the dissipated power, and the current drive efficiency. These expressions are fully relativistic and are valid over the whole admissible range of frequencies and for allmore » electron temperatures. The relation between efficiency and parallel relativistic transport coefficients is exhibited. The most important relativistic effect is a dramatic broadening of the frequency range over which the rf-generated current is significantly different from zero.« less

On the application of frequency selective common mode feedback for multifrequency EIT.

PubMed

Langlois, Peter J; Wu, Yu; Bayford, Richard H; Demosthenous, Andreas

2015-06-01

Common mode voltages are frequently a problem in electrical impedance tomography (EIT) and other bioimpedance applications. To reduce their amplitude common mode feedback is employed. Formalised analyses of both current and voltage feedback is presented in this paper for current drives. Common mode effects due to imbalances caused by the current drives, the electrode connections to the body load and the introduction of the body impedance to ground are considered. Frequency selective narrowband common mode feedback previously proposed to provide feedback stability is examined. As a step towards multifrequency applications the use of narrowband feedback is experimentally demonstrated for two simultaneous current drives. Measured results using standard available components show a reduction of 62 dB for current feedback and 31 dB for voltage feedback. Frequencies ranged from 50 kHz to 1 MHz.

A driving cycle for vehicle emissions estimation in the metropolitan area of Mexico City.

PubMed

Schifter, I; Díaz, L; Rodríguez, R; López-Salinas, E

2005-02-01

A driving cycle derived from driving behavior and real traffic conditions in Mexico City (MC) is proposed. Data acquisition was carried out over diverse MC routes, representing travel under congested and uncongested conditions, using the chase-car approach. Thirteen different on-road patterns, including the four main access roads to MC, trips in both directions and different timetables, a total of 108 trips spanning 1044 km were evaluated in this study. The MC cycle lasts 1360 seconds with a distance of 8.8 km and average speed of 23.4 km h(-1). Both maximum speed (73.6 km h(-1)) and maximum acceleration (2.22 km h(-1)s(-1)) are lower than those of the new vehicles certification employed in Mexico ,FTP-75 cycle., that is, the MC cycle exhibits less cruising time and more transient events than the FTP cycle. A total of 30 light duty gasoline vehicles were classified into different technological groups and tested in an FTP-75 and MC driving cycles in order to compare their emission factors A potential concern is that in Mexico manufacturers design vehicles to meet the emission standards in the FTP, but emission levels increase significantly in a more representative cycle of present driving patterns in the Metropolitan Area of Mexico City (MAMC). The use of a more representative cycle during certification testing, would provide an incentive for vehicle manufacturers to design emissions control systems to remain effective during operation modes that are not currently represented in the official test procedures used in the certification process. Based on the results of the study, the use of MC cycle, which better represents current day driving patterns during testing of vehicle fleets in emissions laboratories, would improve the accuracy of emissions factors used in the MAMC emissions inventories.

Assessment of real driving emissions via portable emission measurement system

NASA Astrophysics Data System (ADS)

Clenci, A.; Sălan, V.; Niculescu, R.; Iorga-Simăn, V.; Zaharia, C.

2017-10-01

The European Commission approved a so-called Real Driving Emission (RDE) test in response to the criticisms to the current driving cycle used at chassis dyno for homologation purpose (NEDC): it is considered outdated and misleading since air pollutants in real driving conditions are considerably higher than the certification thresholds. So, what’s at stake is the air quality which degraded continuously despite the ever-increasing severity of the regulations during the last almost three decades. Thus, from September 2017, the RDE test will become part of the type approval process for all cars sold in Europe. As its name points out, it will include “real world driving” using a portable emissions measurement system (PEMS). The paper presents the RDE features (PEMS mounting, testing environment, boundary conditions, driving dynamics) and presents a case study on the influence of the driving style upon the tail-pipe emissions under the RDE testing. The results presented in the paper issued from the existing cooperation on this topic between University of Pitesti and Renault Technologie Roumanie

Alcohol & drug use among drivers : British Columbia roadside survey 2008

DOT National Transportation Integrated Search

2009-01-01

Following two decades of progress dealing with alcoholimpaired : driving, greater attention is now being : directed toward the issue of driving while impaired by : drugs. Currently, there is far less information related to drug-impaired : driving tha...

Derivation of dynamo current drive in a closed-current volume and stable current sustainment in the HIT-SI experiment

NASA Astrophysics Data System (ADS)

Hossack, A. C.; Sutherland, D. A.; Jarboe, T. R.

2017-02-01

A derivation is given showing that the current inside a closed-current volume can be sustained against resistive dissipation by appropriately phased magnetic perturbations. Imposed-dynamo current drive theory is used to predict the toroidal current evolution in the helicity injected torus with steady inductive helicity injection (HIT-SI) experiment as a function of magnetic fluctuations at the edge. Analysis of magnetic fields from a HIT-SI discharge shows that the injector-imposed fluctuations are sufficient to sustain the measured toroidal current without instabilities whereas the small, plasma-generated magnetic fluctuations are not sufficiently large to sustain the current.

What is eating you? Stress and the drive to eat.

PubMed

Groesz, Lisa M; McCoy, Shannon; Carl, Jenna; Saslow, Laura; Stewart, Judith; Adler, Nancy; Laraia, Barbara; Epel, Elissa

2012-04-01

Non-human animal studies demonstrate relationships between stress and selective intake of palatable food. In humans, exposure to laboratory stressors and self-reported stress are associated with greater food intake. Large studies have yet to examine chronic stress exposure and eating behavior. The current study assessed the relationship between stress (perceived and chronic), drive to eat, and reported food frequency intake (nutritious food vs. palatable non-nutritious food) in women ranging from normal weight to obese (N=457). Greater reported stress, both exposure and perception, was associated with indices of greater drive to eat-including feelings of disinhibited eating, binge eating, hunger, and more ineffective attempts to control eating (rigid restraint; r's from .11 to .36, p's<.05). These data suggest that stress exposure may lead to a stronger drive to eat and may be one factor promoting excessive weight gain. Relationships between stress and eating behavior are of importance to public health given the concurrent increase in reported stress and obesity rates. Copyright © 2011 Elsevier Ltd. All rights reserved.

Genetic and nonshared environmental factors affect the likelihood of being charged with driving under the influence (DUI) and driving while intoxicated (DWI).

PubMed

Beaver, Kevin M; Barnes, J C

2012-12-01

Driving under the influence (DUI) and driving while intoxicated (DWI) are related to a range of serious health, legal, and financial costs. Given the costs to society of DUIs and DWIs, there has been interest in identifying the causes of DUIs and DWIs. The current study added to this existing knowledge base by estimating genetic and environmental effects on DUIs and DWIs in a sample of twins drawn from the National Longitudinal Study of Adolescent Health (Add Health). The results of the analyses revealed that genetic factors explained 53% of the variance in DUIs/DWIs and the nonshared environment explained 47% of the variance. Shared environmental factors explained none of the variance in DUIs/DWIs. We conclude with a discussion of the results, the limitations of the study, and how the findings might be compatible with policies designed to reduce DUIs and DWIs. Copyright © 2012 Elsevier Ltd. All rights reserved.

[Driving under the influence of amphetamine and metamphetamine].

PubMed

Lia, Kjersti; Spigset, Olav; Slørdal, Lars

2009-01-15

The CNS stimulatory agents amphetamine and methamphetamine are often detected in blood samples from apprehended subjects driving under the influence of drugs. Relevant literature was identified through searches in PubMed and Google Scholar. The current state of knowledge regarding effects of amphetamines on traffic behaviour is reviewed and discussed. Limited epidemiological data and a small number of experimental studies using low doses of amphetamines are available. Low amphetamine doses have been associated with enhanced performance in studies of sleep-deprived subjects. Theoretical considerations and empirical observations suggest that higher doses may impede performance, but not in accordance with usual concentration/effect relationships. There is a conspicuous lack of data on how to handle cases of driving under the influence of amphetamines.

We can predict when driving is no longer safe for people who have HD using standard neuropsychological measures.

PubMed

Hennig, Bonnie L; Kaplan, Richard F; Nowicki, Ariel E; Barclay, Jessy E; Gertsberg, Anna G

2014-01-01

Early cognitive dysfunction in Huntington's Disease (HD) is typically of a subcortical frontal executive type, with bradyphrenia, poor spatial and working memory, poor planning and organization, a lack of judgment, and poor mental flexibility. Although there is literature suggesting a correlation between deficits in speed of processing, working memory and executive function on driving competency, there is little direct evidence comparing these declines on tests to actual driving skills. The current study examines the utility of specific neuropsychological measures in predicting actual driving competency in patients with HD. Fifty-two patients at the UConn Health HD Program underwent yearly neuropsychological evaluations and were included in this study. Four scales were chosen a priori to predict driving impairment because of their reported relationship to driving ability. Within each test category, subjects who scored below the threshold suggestive of neurological impairment were found to have results within the impaired range (1.5 standard deviations below corrective normative data). A referral to the Connecticut Department of Motor Vehicles (DMV) for a driving evaluation was subsequently made on patients who were found impaired on any two of these tests. The authors found a strong relationship between scores on a simple battery of four neuropsychological tests and driving competency. This short battery may prove of pragmatic value for clinicians working with people with HD and their families.

Electron Temperature Evolution During Local Helicity Injection on the Pegasus Toroidal Experiment

NASA Astrophysics Data System (ADS)

Schlossberg, D. J.; Barr, J. L.; Bodner, G. M.; Bongard, M. W.; Fonck, R. J.; Perry, J. M.; Reusch, J. A.; Rodriguez Sanchez, C.

2016-10-01

Understanding the electron temperature (Te) evolution during local helicity injection (LHI) is critical for scaling up this non-solenoidal startup technique to MA-class devices. The first comprehensive Te measurements during LHI reveal centrally-peaked profiles with Te > 100 eV for plasma current Ip > 120 kA, toroidal field 0.15 T, and electron density ne 1019 m-3. Te rises and is sustained from just after magnetic relaxation through the plasma decoupling from edge-localized injectors. Results are presented for two injector edge locations: outboard midplane and inboard divertor. Outboard midplane injection couples LHI with inductive drive from poloidal field ramps and radial compression during inward plasma growth. Comparisons of Te at different LHI-to-inductive drive ratios show some profile flattening for higher LHI drive fraction. The latter, constant-shape discharges were necessarily lower performance, with Ip 50 kA and reduced Te , max. Inboard divertor injection achieves higher Ip using minimal inductive drive and thus isolates effects of LHI drive on Te. Initial results in this configuration show Te rising rapidly at the injector location as the discharge grows, settling to a roughly flat profile 100 eV. Thus far, both scenarios provide relatively stable discharges with moderate ne and high-Te, suitable for coupling to auxiliary current drive. Detailed studies of confinement dynamics and discharge optimization are planned for the near future. Work supported by US DOE Grant DE-FG02-96ER54375.

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.

Modelling of the EAST lower-hybrid current drive experiment using GENRAY/CQL3D and TORLH/CQL3D

NASA Astrophysics Data System (ADS)

Yang, C.; Bonoli, P. T.; Wright, J. C.; Ding, B. J.; Parker, R.; Shiraiwa, S.; Li, M. H.

2014-12-01

The coupled GENRAY-CQL3D code has been used to do systematic ray-tracing and Fokker-Planck analysis for EAST Lower Hybrid wave Current Drive (LHCD) experiments. Despite being in the weak absorption regime, the experimental level of LH current drive is successfully simulated, by taking into account the variations in the parallel wavenumber due to the toroidal effect. The effect of radial transport of the fast LH electrons in EAST has also been studied, which shows that a modest amount of radial transport diffusion can redistribute the fast LH current significantly. Taking advantage of the new capability in GENRAY, the actual Scrape Off Layer (SOL) model with magnetic field, density, temperature, and geometry is included in the simulation for both the lower and the higher density cases, so that the collisional losses of Lower Hybrid Wave (LHW) power in the SOL has been accounted for, which together with fast electron losses can reproduce the LHCD experimental observations in different discharges of EAST. We have also analyzed EAST discharges where there is a significant ohmic contribution to the total current, and good agreement with experiment in terms of total current has been obtained. Also, the full-wave code TORLH has been used for the simulation of the LH physics in the EAST, including full-wave effects such as diffraction and focusing which may also play an important role in bridging the spectral gap. The comparisons between the GENRAY and the TORLH codes are done for both the Maxwellian and the quasi-linear electron Landau damping cases. These simulations represent an important addition to the validation studies of the GENRAY-CQL3D and TORLH models being used in weak absorption scenarios of tokamaks with large aspect ratio.

Genuine Quantum Signatures in Synchronization of Anharmonic Self-Oscillators.

PubMed

Lörch, Niels; Amitai, Ehud; Nunnenkamp, Andreas; Bruder, Christoph

2016-08-12

We study the synchronization of a Van der Pol self-oscillator with Kerr anharmonicity to an external drive. We demonstrate that the anharmonic, discrete energy spectrum of the quantum oscillator leads to multiple resonances in both phase locking and frequency entrainment not present in the corresponding classical system. Strong driving close to these resonances leads to nonclassical steady-state Wigner distributions. Experimental realizations of these genuine quantum signatures can be implemented with current technology.

Alternating-Current Motor Drive for Electric Vehicles

NASA Technical Reports Server (NTRS)

Krauthamer, S.; Rippel, W. E.

1982-01-01

New electric drive controls speed of a polyphase as motor by varying frequency of inverter output. Closed-loop current-sensing circuit automatically adjusts frequency of voltage-controlled oscillator that controls inverter frequency, to limit starting and accelerating surges. Efficient inverter and ac motor would give electric vehicles extra miles per battery charge.

Underwater noise reduction of marine pile driving using a double pile.

DOT National Transportation Integrated Search

2015-12-01

Impact pile driving of steel piles in marine environments produces extremely high sound levels in the water. : It has been shown that current pile driving noise attenuation techniques, such as bubble curtains and : cofferdams, provide limited noise r...

Investigating driving behaviour of older drivers with mild cognitive impairment using a portable driving simulator.

PubMed

Devlin, Anna; McGillivray, Jane; Charlton, Judith; Lowndes, Georgia; Etienne, Virginie

2012-11-01

While there is a large body of research indicating that individuals with moderate to severe dementia are unfit to drive, relatively little is known about the driving performance of older drivers with mild cognitive impairment (MCI). The aim of the current study was to examine the driving performance of older drivers with MCI on approach to intersections, and to investigate how their healthy counterparts perform on the same driving tasks using a portable driving simulator. Fourteen drivers with MCI and 14 age-matched healthy older drivers (aged 65-87 years) completed a 10-min simulator drive in an urban environment. The simulator drive consisted of stop-sign controlled and signal-controlled intersections. Drivers were required to stop at the stop-sign controlled intersections and to decide whether or not to proceed through a critical light change at the signal-controlled intersections. The specific performance measures included; approach speed, number of brake applications on approach to the intersection (either excessive or minimal), failure to comply with stop signs, and slower braking response times on approach to a critical light change. MCI patients in our sample performed more poorly than controls across a number of variables. However, because the trends failed to reach statistical significance it will be important to replicate the study using a larger sample to qualify whether the results can be generalised to the broader population. Copyright © 2012 Elsevier Ltd. All rights reserved.

Direct and Indirect Effects of Impulsivity Traits on Drinking and Driving in Young Adults

PubMed Central

Treloar, Hayley R.; Morris, David H.; Pedersen, Sarah L.; McCarthy, Denis M.

2012-01-01

Objective: Impulsivity is strongly associated with alcohol-related risk-taking behavior, and this association has been found to be mediated by alcohol cognitions. The current study expanded this literature by comparing the relative association of distinct impulsivity traits with a specific risky behavior—drinking and driving. We then tested whether drinking-and-driving expectancies uniquely mediated this relation over and above other cognitions about alcohol and drinking and driving. Method: College student drivers (n = 816; 53.6% women) completed a paper-and-pencil survey in small groups. Self-report measures assessed alcohol use, impulsivity traits, alcohol expectancies, drinking-and-driving cognitions (i.e., expectancies, attitudes, beliefs), and drinking and driving. Results: Although all impulsivity traits were correlated with drinking and driving, only urgency uniquely contributed to drinking and driving. Indirect effect tests indicated that drinking-and-driving convenience expectancies partially mediated this association as well as that between (lack of) perseverance and drinking and driving. These results remained significant after controlling for alcohol expectancies and other drinking-and-driving cognitions. Conclusions: These findings highlight the importance of distinguishing among impulsivity traits to improve theoretical models of the processes by which personality leads to specific alcohol-related consequences. In addition, results extend previous research by providing evidence for the unique importance of expectancies regarding the convenience of drinking and driving over and above more global alcohol expectancies and other drinking-and-driving cognitions. PMID:22846243

Both texting and eating are associated with impaired simulated driving performance.

PubMed

Alosco, Michael L; Spitznagel, Mary Beth; Fischer, Kimberly Hall; Miller, Lindsay A; Pillai, Vivek; Hughes, Joel; Gunstad, John

2012-09-01

Distracted driving is a known contributor to traffic accidents, and many states have banned texting while driving. However, little is known about the potential accident risk of other common activities while driving, such as eating. The objective of the current study was to examine the adverse impact of eating/drinking behavior relative to texting and nondistracted behaviors on a simulated driving task. A total of 186 participants were recruited from undergraduate psychology courses over 2 semesters at Kent State University. We utilized the Kent Multidimensional Assessment Driving Simulation (K-MADS) to compare simulated driving performance among participants randomly assigned to texting (N = 45), eating (N = 45), and control (N = 96) conditions. Multivariate analyses of variance (MANOVA) were conducted to examine between-group differences on simulated driving indices. MANOVA analyses indicated that groups differed in simulated driving performance, F(14, 366) = 7.70, P < .001. Both texting and eating produced impaired driving performance relative to controls, though these behaviors had approximately equal effect. Specifically, both texting and eating groups had more collisions, pedestrian strikes, and center line crossings than controls. In addition, the texting group had more road edge excursions than either eating or control participants and the eating group missed more stop signs than controls. These findings suggest that both texting and eating are associated with poorer simulated driving performance. Future work is needed to determine whether these findings generalize to real-world driving and the development of strategies to reduce distracted driving.

Biological, Psychological, and Sociocultural Factors Contributing to the Drive for Muscularity in Weight-Training Men

PubMed Central

Schneider, Catharina; Rollitz, Laura; Voracek, Martin; Hennig-Fast, Kristina

2016-01-01

The drive for muscularity and associated behaviors (e.g., exercising and dieting) are of growing importance for men in Western societies. In its extreme form, it can lead to body image concerns and harmful behaviors like over-exercising and the misuse of performance-enhancing substances. Therefore, investigating factors associated with the drive for muscularity, especially in vulnerable populations like bodybuilders and weight trainers can help identify potential risk and protective factors for body image problems. Using a biopsychosocial framework, the aim of the current study was to explore different factors associated with drive for muscularity in weight-training men. To this purpose, German-speaking male weight trainers (N = 248) completed an online survey to determine the extent to which biological, psychological, and sociocultural factors contribute to drive for muscularity and its related attitudes and behaviors. Using multiple regression models, findings showed that media ideal body internalization was the strongest positive predictor for drive for muscularity, while age (M = 25.9, SD = 7.4) held the strongest negative association with drive for muscularity. Dissatisfaction with muscularity, but not with body fat, was related to drive for muscularity. The fat-free mass index, a quantification of the actual degree of muscularity of a person, significantly predicted drive for muscularity-related behavior but not attitudes. Body-related aspects of self-esteem, but not global self-esteem, were significant negative predictors of drive for muscularity. Since internalization of media body ideals presented the highest predictive value for drive for muscularity, these findings suggest that media body ideal internalizations may be a risk factor for body image concerns in men, leading, in its most extreme form to disordered eating or muscle dysmorphia. Future research should investigate the relations between drive for muscularity, age, body composition, internalization, dissatisfaction with muscularity and body-related self-esteem using longitudinal study designs. Limitations concern the cross-sectional design of the study, self-reported body composition measures and the homogeneity of the sample. PMID:28066308

Psychometrics of the AAN Caregiver Driving Safety Questionnaire and contributors to caregiver concern about driving safety in older adults.

PubMed

Carvalho, Janessa O; Springate, Beth; Bernier, Rachel A; Davis, Jennifer

2018-03-01

ABSTRACTBackground:The American Academy of Neurology (AAN) updated their practice parameters in the evaluation of driving risk in dementia and developed a Caregiver Driving Safety Questionnaire, detailed in their original manuscript (Iverson Gronseth, Reger, Classen, Dubinsky, & Rizzo, 2010). They described four factors associated with decreased driving ability in dementia patients: history of crashes or citations, informant-reported concerns, reduced mileage, and aggressive driving. An informant-reported AAN Caregiver Driving Safety Questionnaire was designed with these elements, and the current study was the first to explore the factor structure of this questionnaire. Additionally, we examined associations between these factors and cognitive and behavioral measures in patients with mild cognitive impairment or early Alzheimer's disease and their informants. Exploratory factor analysis revealed a four-component structure, consistent with the theory behind the AAN scale composition. These four factor scores also were significantly associated with performance on cognitive screening instruments and informant reported behavioral dysfunction. Regressions revealed that behavioral dysfunction predicted caregiver concerns about driving safety beyond objective patient cognitive dysfunction. In this first known quantitative exploration of the scale, our results support continued use of this scale in office driving safety assessments. Additionally, patient behavioral changes predicted caregiver concerns about driving safety over and above cognitive status, which suggests that caregivers may benefit from psychoeducation about cognitive factors that may negatively impact driving safety.

Impacts of Thermal Atomic Layer-Deposited AlN Passivation Layer on GaN-on-Si High Electron Mobility Transistors.

PubMed

Zhao, Sheng-Xun; Liu, Xiao-Yong; Zhang, Lin-Qing; Huang, Hong-Fan; Shi, Jin-Shan; Wang, Peng-Fei

2016-12-01

Thermal atomic layer deposition (ALD)-grown AlN passivation layer is applied on AlGaN/GaN-on-Si HEMT, and the impacts on drive current and leakage current are investigated. The thermal ALD-grown 30-nm amorphous AlN results in a suppressed off-state leakage; however, its drive current is unchanged. It was also observed by nano-beam diffraction method that thermal ALD-amorphous AlN layer barely enhanced the polarization. On the other hand, the plasma-enhanced chemical vapor deposition (PECVD)-deposited SiN layer enhanced the polarization and resulted in an improved drive current. The capacitance-voltage (C-V) measurement also indicates that thermal ALD passivation results in a better interface quality compared with the SiN passivation.

The influence of music on mental effort and driving performance.

PubMed

Ünal, Ayça Berfu; Steg, Linda; Epstude, Kai

2012-09-01

The current research examined the influence of loud music on driving performance, and whether mental effort mediated this effect. Participants (N=69) drove in a driving simulator either with or without listening to music. In order to test whether music would have similar effects on driving performance in different situations, we manipulated the simulated traffic environment such that the driving context consisted of both complex and monotonous driving situations. In addition, we systematically kept track of drivers' mental load by making the participants verbally report their mental effort at certain moments while driving. We found that listening to music increased mental effort while driving, irrespective of the driving situation being complex or monotonous, providing support to the general assumption that music can be a distracting auditory stimulus while driving. However, drivers who listened to music performed as well as the drivers who did not listen to music, indicating that music did not impair their driving performance. Importantly, the increases in mental effort while listening to music pointed out that drivers try to regulate their mental effort as a cognitive compensatory strategy to deal with task demands. Interestingly, we observed significant improvements in driving performance in two of the driving situations. It seems like mental effort might mediate the effect of music on driving performance in situations requiring sustained attention. Other process variables, such as arousal and boredom, should also be incorporated to study designs in order to reveal more on the nature of how music affects driving. Copyright © 2012 Elsevier Ltd. All rights reserved.

Simulation model for a seven-phase BLDCM drive system

NASA Astrophysics Data System (ADS)

Park, Sang-Hoon; Lee, Won-Cheol; Lee, Jung-Hyo; Yu, Jae-Sung; Kim, Gyu-Sik; Won, Chung-Yuen

2007-12-01

BLDC motors have many advantages over brushed DC motors and induction motors. So, BLDC motors extend their application to many industrial fields. In this paper, the digital simulation and modeling of a 7-phase brushless DC motor have been presented. The 14-switch inverter and a 7-phase brushless DC motor drive system are simulated using hysteresis current controller and logic of switching pattern with the Boolean¡s function. Through some simulations, we found that our modeling and analysis of a 7-phase BLDCM with PWM inverter would be helpful for the further studies of the multi-phase BLDCM drive systems.

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.

The contribution of perceived parental and familial characteristics to attitudes toward accompanied driving among young drivers.

PubMed

Taubman-Ben-Ari, Orit

2011-09-01

One of the main requirements of the graduated driving licensing system in Israel is that new drivers be accompanied by an experienced driver (usually one of their parents) for the first three months after receipt of their license. The current series of studies examined the associations between young drivers' attitudes toward accompanied driving (ATAD) and their perception of their parents' driving styles and parenting modes, as well as dynamic of their family. Young drivers completed questionnaires assessing their ATAD, and either perceived parental driving style (Study 1, n=100), perceived parenting style (Study 2, n=120), or perceived family dynamic (Study 3, n=254). The results indicated significant associations between the young drivers' ATAD of tension, relatedness, avoidance, disapproval, and anxiety, and their own perceptions of the characteristic driving styles of their parents (risky, anxious, angry, and careful). They also indicated significant relationship between youngsters' ATAD and their perceptions of their parents' parenting modes (responsive, demanding, and autonomy-granting). Finally, the results indicated significant negative associations between ATAD of tension, avoidance, disapproval, and anxiety, and family cohesion and adaptability, and a positive association between these two and relatedness. The results are discussed in respect to the relationship between the parental model and the young drivers' ATAD in particular, and risk management in general, and practical implications of these results are offered. Copyright © 2011 Elsevier Ltd. All rights reserved.

Evaluation of semiconductor devices for Electric and Hybrid Vehicle (EHV) ac-drive applications, volume 1

NASA Technical Reports Server (NTRS)

Lee, F. C.; Chen, D. Y.; Jovanovic, M.; Hopkins, D. C.

1985-01-01

The results of evaluation of power semiconductor devices for electric hybrid vehicle ac drive applications are summarized. Three types of power devices are evaluated in the effort: high power bipolar or Darlington transistors, power MOSFETs, and asymmetric silicon control rectifiers (ASCR). The Bipolar transistors, including discrete device and Darlington devices, range from 100 A to 400 A and from 400 V to 900 V. These devices are currently used as key switching elements inverters for ac motor drive applications. Power MOSFETs, on the other hand, are much smaller in current rating. For the 400 V device, the current rating is limited to 25 A. For the main drive of an electric vehicle, device paralleling is normally needed to achieve practical power level. For other electric vehicle (EV) related applications such as battery charger circuit, however, MOSFET is advantageous to other devices because of drive circuit simplicity and high frequency capability. Asymmetrical SCR is basically a SCR device and needs commutation circuit for turn off. However, the device poses several advantages, i.e., low conduction drop and low cost.

Amplitude-frequency effect of Y-cut langanite and langatate.

PubMed

Kim, Yoonkee

2003-12-01

Amplitude-frequency effect of a Y-cut langanite (LGN) resonator and a Y-cut langatate (LGT) resonator were measured. The frequency shifts from the baseline frequency with 1 mA were measured as a function of drive currents up to 28 mA. High-drive current shifted the frequency, but it also heated the crystal locally, causing temperature-related frequency changes. The local heat transfer and its influence on the frequency were analyzed. The amplitude-frequency shift was effectively measured, and was not affected by the temperature-related frequency changes. The 3rd, 5th, and 7th overtones (OT's) were found to behave as soft springs, i.e., resonant frequency decreases as drive current increases. The drive sensitivity coefficients of the 3rd and 5th OT's are in the vicinity of -2 ppb/mA2 for both resonators. The 7th OT's are higher than the other OT's: -5 approximately -7 ppb/mA2. The lowest drive sensitivity is -1.2 ppb/mA2 on the 5th OT of the LGT.

Rifaximin Improves Driving Simulator Performance in a Randomized Trial of Patients with Minimal Hepatic Encephalopathy

PubMed Central

Bajaj, Jasmohan S; Heuman, Douglas M; Wade, James B; Gibson, Douglas P; Saeian, Kia; Wegelin, Jacob A; Hafeezullah, Muhammad; Bell, Debulon E; Sterling, Richard K; Stravitz, R. Todd; Fuchs, Michael; Luketic, Velimir; Sanyal, Arun J

2010-01-01

Background & Aims Patients with cirrhosis and minimal hepatic encephalopathy (MHE) have driving difficulties but the effects of therapy on driving performance have not been assessed. We evaluated whether performance on a driving simulator improves in patients with MHE following treatment with rifaximin. Methods Patients with MHE who were current drivers were randomly assigned to placebo or rifaximin groups and followed for 8 weeks (n=42). Patients underwent driving simulation (driving and navigation tasks) at the start (baseline) and end of the study. We evaluated patients’ cognitive abilities, quality-of-life (using the Sickness Impact Profile [SIP]), serum levels of ammonia, levels of inflammatory cytokines, and MELD scores. The primary outcome was percent who improved in driving performance, calculated by: total driving errors=speeding + illegal turns + collisions. Results Over the 8-week study period, patients given rifaximin made significantly greater improvements than those given placebo in avoiding total driving errors (76% vs. 31%, P=0.013), speeding (81% vs. 33%, P=0.005), and illegal turns (62% vs. 19%, P=0.01). Of patients given rifaximin, 91% improved their cognitive performance, compared with 61% of patients given placebo (P=0.01); they also made improvements in the psycho-social dimension of the SIP, compared with the placebo group (P=0.04). Adherence to the assigned drug averaged 92%. Neither group had changes in ammonia levels or MELD scores, but patients in the rifaximin group had increased levels of the anti-inflammatory cytokine interleukin-10. Conclusions Patients with MHE significantly improve driving simulator performance following treatment with rifaximin, compared with placebo. PMID:20849805

Nanowire Tunnel Field Effect Transistors: Prospects and Pitfalls

NASA Astrophysics Data System (ADS)

Sylvia, Somaia Sarwat

The tunnel field effect transistor (TFET) has the potential to operate at lower voltages and lower power than the field effect transistor (FET). The TFET can circumvent the fundamental thermal limit of the inverse subthreshold slope (S) by exploiting interband tunneling of non-equilibrium "cold" carriers. The conduction mechanism in the TFET is governed by band-to-band tunneling which limits the drive current. TFETs built with III-V materials like InAs and InSb can produce enough tunneling current because of their small direct bandgap. Our simulation results show that although they require highly degenerate source doping to support the high electric fields in the tunnel region, the devices achieve minimum inverse subthreshold slopes of 30 mV/dec. In subthreshold, these devices experience both regimes of voltage-controlled tunneling and cold-carrier injection. Numerical results based on a discretized 8-band k.p model are compared to analytical WKB theory. For both regular FETs and TFETs, direct channel tunneling dominates the leakage current when the physical gate length is reduced to 5 nm. Therefore, a survey of materials is performed to determine their ability to suppress the direct tunnel current through a 5 nm barrier. The tunneling effective mass gives the best indication of the relative size of the tunnel currents. Si gives the lowest overall tunnel current for both the conduction and valence band and, therefore, it is the optimum choice for suppressing tunnel current at the 5 nm scale. Our numerical simulation shows that the finite number, random placement, and discrete nature of the dopants in the source of an InAs nanowire (NW) TFET affect both the mean value and the variance of the drive current and the inverse subthreshold slope. The discrete doping model gives an average drive current and an inverse subthreshold slope that are less than those predicted from the homogeneous doping model. The doping density required to achieve a target drive current is higher in the discrete doping model compared to the homogeneous doping model. The relative variation in the ON current decreases as the average doping density and/or NW diameter increases. For the largest 8 nm NW studied, the coefficient of variation in the ON current is ˜15% at a doping density of 1.5 x 1020 cm--3. Results from full self-consistent non-equilibrium Green's function calculations and semi-classical calculations are compared.

Base drive for paralleled inverter systems

NASA Technical Reports Server (NTRS)

Nagano, S. (Inventor)

1980-01-01

In a paralleled inverter system, a positive feedback current derived from the total current from all of the modules of the inverter system is applied to the base drive of each of the power transistors of all modules, thereby to provide all modules protection against open or short circuit faults occurring in any of the modules, and force equal current sharing among the modules during turn on of the power transistors.

AORSA full wave calculations of helicon waves in DIII-D and ITER

NASA Astrophysics Data System (ADS)

Lau, C.; Jaeger, E. F.; Bertelli, N.; Berry, L. A.; Green, D. L.; Murakami, M.; Park, J. M.; Pinsker, R. I.; Prater, R.

2018-06-01

Helicon waves have been recently proposed as an off-axis current drive actuator for DIII-D, FNSF, and DEMO tokamaks. Previous ray tracing modeling using GENRAY predicts strong single pass absorption and current drive in the mid-radius region on DIII-D in high beta tokamak discharges. The full wave code AORSA, which is valid to all order of Larmor radius and can resolve arbitrary ion cyclotron harmonics, has been used to validate the ray tracing technique. If the scrape-off-layer (SOL) is ignored in the modeling, AORSA agrees with GENRAY in both the amplitude and location of driven current for DIII-D and ITER cases. These models also show that helicon current drive can possibly be an efficient current drive actuator for ITER. Previous GENRAY analysis did not include the SOL. AORSA has also been used to extend the simulations to include the SOL and to estimate possible power losses of helicon waves in the SOL. AORSA calculations show that another mode can propagate in the SOL and lead to significant (~10%–20%) SOL losses at high SOL densities. Optimizing the SOL density profile can reduce these SOL losses to a few percent.

AORSA full wave calculations of helicon waves in DIII-D and ITER

DOE PAGES

Lau, Cornwall; Jaeger, E.F.; Bertelli, Nicola; ...

2018-04-11

Helicon waves have been recently proposed as an off-axis current drive actuator for DIII-D, FNSF, and DEMO tokamaks. Previous ray tracing modeling using GENRAY predicts strong single pass absorption and current drive in the mid-radius region on DIII-D in high beta tokamak discharges. The full wave code AORSA, which is valid to all order of Larmor radius and can resolve arbitrary ion cyclotron harmonics, has been used to validate the ray tracing technique. If the scrape-off-layer (SOL) is ignored in the modeling, AORSA agrees with GENRAY in both the amplitude and location of driven current for DIII-D and ITER cases.more » These models also show that helicon current drive can possibly be an efficient current drive actuator for ITER. Previous GENRAY analysis did not include the SOL. AORSA has also been used to extend the simulations to include the SOL and to estimate possible power losses of helicon waves in the SOL. AORSA calculations show that another mode can propagate in the SOL and lead to significant (~10-20%) SOL losses at high SOL densities. Optimizing the SOL density profile can reduce these SOL losses to a few percent.« less

AORSA full wave calculations of helicon waves in DIII-D and ITER

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

Lau, Cornwall; Jaeger, E.F.; Bertelli, Nicola

Helicon waves have been recently proposed as an off-axis current drive actuator for DIII-D, FNSF, and DEMO tokamaks. Previous ray tracing modeling using GENRAY predicts strong single pass absorption and current drive in the mid-radius region on DIII-D in high beta tokamak discharges. The full wave code AORSA, which is valid to all order of Larmor radius and can resolve arbitrary ion cyclotron harmonics, has been used to validate the ray tracing technique. If the scrape-off-layer (SOL) is ignored in the modeling, AORSA agrees with GENRAY in both the amplitude and location of driven current for DIII-D and ITER cases.more » These models also show that helicon current drive can possibly be an efficient current drive actuator for ITER. Previous GENRAY analysis did not include the SOL. AORSA has also been used to extend the simulations to include the SOL and to estimate possible power losses of helicon waves in the SOL. AORSA calculations show that another mode can propagate in the SOL and lead to significant (~10-20%) SOL losses at high SOL densities. Optimizing the SOL density profile can reduce these SOL losses to a few percent.« less

Pushing Particles with Waves: Current Drive and α-Channeling

DOE PAGES

FISCH, Nathaniel J.

2016-01-01

It can be advantageous to push particles with waves in tokamaks or other magnetic confinement devices, relying on wave-particle resonances to accomplish specific goals. Waves that damp on electrons or ions in toroidal fusion devises can drive currents if the waves are launched with toroidal asymmetry. Theses currents are important for tokamaks, since they operate in the absence of an electric field with curl, enabling steady state operation. The lower hybrid wave and the electron cyclotron wave have been demonstrated to drive significant currents. Non-inductive current also stabilizes deleterious tearing modes. Waves can also be used to broker the energymore » transfer between energetic alpha particles and the background plasma. Alpha particles born through fusion reactions in a tokamak reactor tend to slow down on electrons, but that could take up to hundreds of milliseconds. Before that happens, the energy in these alpha particles can destabilize on collisionless timescales toroidal Alfven modes and other waves, in a way deleterious to energy confinement. However, it has been speculated that this energy might be instead be channeled instead into useful energy, that heats fuel ions or drives current. Furthermore, an important question is the extent to which these effects can be accomplished together.« less

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.

Effect of heating on the suppression of tearing modes in tokamaks.

PubMed

Classen, I G J; Westerhof, E; Domier, C W; Donné, A J H; Jaspers, R J E; Luhmann, N C; Park, H K; van de Pol, M J; Spakman, G W; Jakubowski, M W

2007-01-19

The suppression of (neoclassical) tearing modes is of great importance for the success of future fusion reactors like ITER. Electron cyclotron waves can suppress islands, both by driving noninductive current in the island region and by heating the island, causing a perturbation to the Ohmic plasma current. This Letter reports on experiments on the TEXTOR tokamak, investigating the effect of heating, which is usually neglected. The unique set of tools available on TEXTOR, notably the dynamic ergodic divertor to create islands with a fully known driving term, and the electron cyclotron emission imaging diagnostic to provide detailed 2D electron temperature information, enables a detailed study of the suppression process and a comparison with theory.

Risky driving among young Australian drivers: trends, precursors and correlates.

PubMed

Vassallo, Suzanne; Smart, Diana; Sanson, Ann; Harrison, Warren; Harris, Anne; Cockfield, Samantha; McIntyre, Allison

2007-05-01

Young drivers are significantly over-represented among those injured or killed in road traffic accidents. Young adults' greater tendency to engage in risky driving behaviours has been implicated in their high crash involvement rate. While considerable research has examined the driving patterns of young adults and situational factors associated with their involvement in crashes, less is known about the characteristics or circumstances in young drivers' earlier lives that may have contributed to their current driving behaviour. This issue was explored using data from the Australian Temperament Project (ATP), a large longitudinal community-based study, which commenced in 1983 with 2443 families and has followed children's psychosocial development from infancy to early adulthood. During the most recent survey wave when participants were aged 19-20 years, information was collected from young adults about their driving experiences and behaviour. A series of analyses indicated that it was possible to distinguish a group of young adults who engaged in high risky driving behaviour (high group) from a group who engaged in low levels of risky driving behaviour (low group) from mid childhood. Young drivers with a tendency towards risky driving differed from others on aspects of temperament style, behaviour problems, social competence, school adjustment and interpersonal relationships. The implications of these findings for initiatives to reduce risky driving behaviour are discussed.

INTERACTIONS BETWEEN AGE AND MODERATE ALCOHOL EFFECTS ON SIMULATED DRIVING PERFORMANCE

PubMed Central

Sklar, Alfredo L.; Boissoneault, Jeff; Fillmore, Mark T.; Nixon, Sara Jo

2013-01-01

Rationale There is a substantial body of literature documenting the deleterious effects of both alcohol consumption and age on driving performance. There is, however, limited work examining the interaction of age and acute alcohol consumption. Objectives The current study was conducted to determine if moderate alcohol doses differentially affect the driving performance of older and younger adults. Methods Healthy older (55 – 70) and younger (25 – 35) adults were tested during a baseline session and again following consumption of one of three beverages (0.0% (placebo), 0.04% or 0.065% target breath alcohol concentration). Measures of driving precision and average speed were recorded. Results Older adults performed more poorly on precision driving measures and drove more slowly than younger adults at baseline. After controlling for baseline performance, interactions between alcohol and age were observed following beverage consumption on two measures of driving precision with older adults exhibiting greater impairment as a result of alcohol consumption. Conclusions These data provide evidence that older adults may be more susceptible to the effects of alcohol on certain measures of driving performance. An investigation of mechanisms accounting for alcohol’s effects on driving in older and younger adults is required. Further evaluation using more complex driving environments is needed to assess the real-world implication of this interaction. PMID:24030469

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.

The need for drugged driving per se laws: a commentary.

PubMed

DuPont, Robert L; Voas, Robert B; Walsh, J Michael; Shea, Corinne; Talpins, Stephen K; Neil, Mark M

2012-01-01

Triggered by the new federal commitment announced by the Office of National Drug Control Policy (ONCDP) to encourage states to enact drugged driving per se laws, this article reviews the reasons to establish such laws and the issues that may arise when trying to enforce them. A review of the state of drunk driving per se laws and their implications for drugged driving is presented, with a review of impaired driving enforcement procedures and drug testing technology. Currently, enforcement of drugged driving laws is an adjunct to the enforcement of laws regarding alcohol impairment. Drivers are apprehended when showing signs of alcohol intoxication and only in the relatively few cases where the blood alcohol concentration of the arrested driver does not account for the observed behavior is the possibility of drug impairment pursued. In most states, the term impaired driving covers both alcohol and drug impairment; thus, driver conviction records may not distinguish between the two different sources of impairment. As a result, enforcement statistics do not reflect the prevalence of drugged driving. Based on the analysis presented, this article recommends a number of steps that can be taken to evaluate current drugged driving enforcement procedures and to move toward the enactment of drug per se laws.

Driving context influences drivers' decision to engage in visual-manual phone tasks: Evidence from a naturalistic driving study.

PubMed

Tivesten, Emma; Dozza, Marco

2015-06-01

Visual-manual (VM) phone tasks (i.e., texting, dialing, reading) are associated with an increased crash/near-crash risk. This study investigated how the driving context influences drivers' decisions to engage in VM phone tasks in naturalistic driving. Video-recordings of 1,432 car trips were viewed to identify VM phone tasks and passenger presence. Video, vehicle signals, and map data were used to classify driving context (i.e., curvature, other vehicles) before and during the VM phone tasks (N=374). Vehicle signals (i.e., speed, yaw rate, forward radar) were available for all driving. VM phone tasks were more likely to be initiated while standing still, and less likely while driving at high speeds, or when a passenger was present. Lead vehicle presence did not influence how likely it was that a VM phone task was initiated, but the drivers adjusted their task timing to situations when the lead vehicle was increasing speed, resulting in increasing time headway. The drivers adjusted task timing until after making sharp turns and lane change maneuvers. In contrast to previous driving simulator studies, there was no evidence of drivers reducing speed as a consequence of VM phone task engagement. The results show that experienced drivers use information about current and upcoming driving context to decide when to engage in VM phone tasks. However, drivers may fail to sufficiently increase safety margins to allow time to respond to possible unpredictable events (e.g., lead vehicle braking). Advanced driver assistance systems should facilitate and possibly boost drivers' self-regulating behavior. For instance, they might recognize when appropriate adaptive behavior is missing and advise or alert accordingly. The results from this study could also inspire training programs for novice drivers, or locally classify roads in terms of the risk associated with secondary task engagement while driving. Copyright © 2015. Published by Elsevier Ltd.

Public Data Set: Initiation and Sustainment of Tokamak Plasmas with Local Helicity Injection as the Majority Current Drive

DOE Data Explorer

Perry, Justin M. [University of Wisconsin-Madison] (ORCID:0000000171228609); Bodner, Grant M. [University of Wisconsin-Madison] (ORCID:0000000324979172); Bongard, Michael W. [University of Wisconsin-Madison] (ORCID:0000000231609746); Burke, Marcus G. [University of Wisconsin-Madison] (ORCID:0000000176193724); Fonck, Raymond J. [University of Wisconsin-Madison] (ORCID:0000000294386762); Pachicano, Jessica L. [University of Wisconsin-Madison] (ORCID:0000000207255693); Pierren, Christopher [University of Wisconsin-Madison] (ORCID:0000000228289825); Reusch, Joshua A. [University of Wisconsin-Madison] (ORCID:0000000284249422); Rhodes, Alexander T. [University of Wisconsin-Madison] (ORCID:0000000280735714); Richner, Nathan J. [University of Wisconsin-Madison] (ORCID:0000000155443915); Rodriguez Sanchez, Cuauhtemoc [University of Wisconsin-Madison] (ORCID:0000000334712586); Schaefer, Carolyn E. [University of Wisconsin-Madison] (ORCID:0000000248848727); Weberski, Justin D. [University of Wisconsin-Madison] (ORCID:0000000256267914)

2018-05-22

This public data set contains openly-documented, machine readable digital research data corresponding to figures published in J.M. Perry et al., 'Initiation and Sustainment of Tokamak Plasmas with Local Helicity Injection as the Majority Current Drive,' accepted for publication in Nuclear Fusion.

Analysis of electric drive technologies for transit applications : battery-electric, hybrid-electric, and fuel cells.

DOT National Transportation Integrated Search

2005-08-01

This report provides an overview of the current status of electric drive technologies for transit applications, covering battery-electric, hybrid-electric : and fuel cell buses. Based on input from the transit and electric drive industries, the analy...

Current profile redistribution driven by neutral beam injection in a reversed-field pinch

NASA Astrophysics Data System (ADS)

Parke, E.; Anderson, J. K.; Brower, D. L.; Den Hartog, D. J.; Ding, W. X.; Johnson, C. A.; Lin, L.

2016-05-01

Neutral beam injection in reversed-field pinch (RFP) plasmas on the Madison Symmetric Torus [Dexter et al., Fusion Sci. Technol. 19, 131 (1991)] drives current redistribution with increased on-axis current density but negligible net current drive. Internal fluctuations correlated with tearing modes are observed on multiple diagnostics; the behavior of tearing mode correlated structures is consistent with flattening of the safety factor profile. The first application of a parametrized model for island flattening to temperature fluctuations in an RFP allows inferrence of rational surface locations for multiple tearing modes. The m = 1, n = 6 mode is observed to shift inward by 1.1 ± 0.6 cm with neutral beam injection. Tearing mode rational surface measurements provide a strong constraint for equilibrium reconstruction, with an estimated reduction of q0 by 5% and an increase in on-axis current density of 8% ± 5%. The inferred on-axis current drive is consistent with estimates of fast ion density using TRANSP [Goldston et al., J. Comput. Phys. 43, 61 (1981)].

Off-axis current drive and real-time control of current profile in JT-60U

NASA Astrophysics Data System (ADS)

Suzuki, T.; Ide, S.; Oikawa, T.; Fujita, T.; Ishikawa, M.; Seki, M.; Matsunaga, G.; Hatae, T.; Naito, O.; Hamamatsu, K.; Sueoka, M.; Hosoyama, H.; Nakazato, M.; JT-60 Team

2008-04-01

Aiming at optimization of current profile in high-β plasmas for higher confinement and stability, a real-time control system of the minimum of the safety factor (qmin) using the off-axis current drive has been developed. The off-axis current drive can raise the safety factor in the centre and help to avoid instability that limits the performance of the plasma. The system controls the injection power of lower-hybrid waves, and hence its off-axis driven current in order to control qmin. The real-time control of qmin is demonstrated in a high-β plasma, where qmin follows the temporally changing reference qmin,ref from 1.3 to 1.7. Applying the control to another high-β discharge (βN = 1.7, βp = 1.5) with m/n = 2/1 neo-classical tearing mode (NTM), qmin was raised above 2 and the NTM was suppressed. The stored energy increased by 16% with the NTM suppressed, since the resonant rational surface was eliminated. For the future use for current profile control, current density profile for off-axis neutral beam current drive (NBCD) is for the first time measured, using the motional Stark effect diagnostic. Spatially localized NBCD profile was clearly observed at the normalized minor radius ρ of about 0.6-0.8. The location was also confirmed by multi-chordal neutron emission profile measurement. The total amount of the measured beam driven current was consistent with the theoretical calculation using the ACCOME code. The CD location in the calculation was inward shifted than the measurement.

Passive Assessment of Routine Driving with Unobtrusive Sensors: A New Approach for Identifying and Monitoring Functional Level in Normal Aging and Mild Cognitive Impairment

PubMed Central

Seelye, Adriana; Mattek, Nora; Sharma, Nicole; Witter, Phelps; Brenner, Ariella; Wild, Katherine; Dodge, Hiroko; Kaye, Jeffrey

2017-01-01

Background Driving is a key functional activity for many older adults, and changes in routine driving may be associated with emerging cognitive decline due to early neurodegenerative disease. Current methods for assessing driving such as self-report are inadequate for identifying and monitoring subtle changes in driving patterns that may be the earliest signals of functional change in developing mild cognitive impairment (MCI). Objective This proof of concept study aimed to establish the feasibility of continuous driving monitoring in a sample of cognitively normal and MCI older adults for an average of 206 days using an unobtrusive driving sensor and demonstrate that derived sensor-based driving metrics could effectively discriminate between MCI and cognitively intact groups. Methods Novel objective driving measures derived from 6 months of routine driving monitoring were examined in older adults with intact cognition (n = 21) and MCI (n = 7) who were enrolled in the Oregon Center for Aging and Technology (ORCATECH) longitudinal assessment program. Results Unobtrusive continuous monitoring of older adults’ routine driving using a driving sensor was feasible and well accepted. MCI participants drove fewer miles and spent less time on the highway per day than cognitively intact participants. MCI drivers showed less day-to-day fluctuations in their driving habits than cognitively intact drivers. Conclusion Sensor-based driving measures are objective, unobtrusive, and can be assessed every time a person drives his or her vehicle to identify clinically meaningful changes in daily driving. This novel methodology has the potential to be useful for the early detection and monitoring of changes in daily functioning within individuals. PMID:28731434

Two-motor direct drive control for elevation axis of telescope

NASA Astrophysics Data System (ADS)

Tang, T.; Tan, Y.; Ren, G.

2014-07-01

Two-motor application has become a very attractive filed in important field which high performance is permitted to achieve of position, speed, and acceleration. In the elevation axis of telescope control system, two-motor direct drive is proposed to enhance the high performance of tracking control system. Although there are several dominant strengths such as low size of motors and high torsional structural dynamics, the synchronization control of two motors is a very difficult and important. In this paper, a multi-loop control technique base master-slave current control is used to synchronize two motors, including current control loop, speed control loop and position control loop. First, the direct drive function of two motors is modeled. Compared of single motor direct control system, the resonance frequency of two motor control systems is same; while the anti-resonance frequency of two motors control system is 1.414 times than those of sing motor system. Because of rigid coupling for direct drive, the speed of two motor of the system is same, and the synchronization of torque for motors is critical. The current master-slave control technique is effective to synchronize the torque, which the current loop of the master motors is tracked the other slave motor. The speed feedback into the input of current loop of the master motors. The experiments test the performance of the two motors drive system. The random tracking error is 0.0119" for the line trajectory of 0.01°/s.

EEG-based decoding of error-related brain activity in a real-world driving task

NASA Astrophysics Data System (ADS)

Zhang, H.; Chavarriaga, R.; Khaliliardali, Z.; Gheorghe, L.; Iturrate, I.; Millán, J. d. R.

2015-12-01

Objectives. Recent studies have started to explore the implementation of brain-computer interfaces (BCI) as part of driving assistant systems. The current study presents an EEG-based BCI that decodes error-related brain activity. Such information can be used, e.g., to predict driver’s intended turning direction before reaching road intersections. Approach. We executed experiments in a car simulator (N = 22) and a real car (N = 8). While subject was driving, a directional cue was shown before reaching an intersection, and we classified the presence or not of an error-related potentials from EEG to infer whether the cued direction coincided with the subject’s intention. In this protocol, the directional cue can correspond to an estimation of the driving direction provided by a driving assistance system. We analyzed ERPs elicited during normal driving and evaluated the classification performance in both offline and online tests. Results. An average classification accuracy of 0.698 ± 0.065 was obtained in offline experiments in the car simulator, while tests in the real car yielded a performance of 0.682 ± 0.059. The results were significantly higher than chance level for all cases. Online experiments led to equivalent performances in both simulated and real car driving experiments. These results support the feasibility of decoding these signals to help estimating whether the driver’s intention coincides with the advice provided by the driving assistant in a real car. Significance. The study demonstrates a BCI system in real-world driving, extending the work from previous simulated studies. As far as we know, this is the first online study in real car decoding driver’s error-related brain activity. Given the encouraging results, the paradigm could be further improved by using more sophisticated machine learning approaches and possibly be combined with applications in intelligent vehicles.

New PMOS LTPS TFT pixel for AMOLED to suppress the hysteresis effect on OLED current by employing a reset voltage driving

NASA Astrophysics Data System (ADS)

Lee, Jae-Hoon; Park, Sang-Geun; Han, Sang-Myeon; Han, Min-Koo; Park, Kee-Chan

2008-03-01

New PMOS LTPS (low temperature polycrystalline silicon)-thin film transistor (TFT) pixel circuit, which can suppress an OLED current error caused by the hysteresis of LTPS-TFT for active matrix organic light emitting diode (AMOLED) display, is proposed and fabricated. The proposed pixel circuit employs a reset voltage driving so that the sweep direction of gate voltage in the current driving TFT is not altered by the gate voltage in the previous frame. Our experimental results show that OLED current error of the proposed pixel is successfully suppressed because a reset voltage can enable the starting gate voltage for a desired one not to be varied, while that of the conventional 2-TFT pixel exceeds over 15% due to the hysteresis of LTPS-TFT.

How safe is tuning a radio?: using the radio tuning task as a benchmark for distracted driving.

PubMed

Lee, Ja Young; Lee, John D; Bärgman, Jonas; Lee, Joonbum; Reimer, Bryan

2018-01-01

Drivers engage in non-driving tasks while driving, such as interactions entertainment systems. Studies have identified glance patterns related to such interactions, and manual radio tuning has been used as a reference task to set an upper bound on the acceptable demand of interactions. Consequently, some view the risk associated with radio tuning as defining the upper limit of glance measures associated with visual-manual in-vehicle activities. However, we have little knowledge about the actual degree of crash risk that radio tuning poses and, by extension, the risk of tasks that have similar glance patterns as the radio tuning task. In the current study, we use counterfactual simulation to take the glance patterns for manual radio tuning tasks from an on-road experiment and apply these patterns to lead-vehicle events observed in naturalistic driving studies. We then quantify how often the glance patterns from radio tuning are associated with rear-end crashes, compared to driving only situations. We used the pre-crash kinematics from 34 crash events from the SHRP2 naturalistic driving study to investigate the effect of radio tuning in crash-imminent situations, and we also investigated the effect of radio tuning on 2,475 routine braking events from the Safety Pilot project. The counterfactual simulation showed that off-road glances transform some near-crashes that could have been avoided into crashes, and glance patterns observed in on-road radio tuning experiment produced 2.85-5.00 times more crashes than baseline driving. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comparison of self-report and objective measures of driving behavior and road safety: A systematic review.

PubMed

Kaye, Sherrie-Anne; Lewis, Ioni; Freeman, James

2018-06-01

This research systematically reviewed the existing literature in regards to studies which have used both self-report and objective measures of driving behavior. The objective of the current review was to evaluate disparities or similarities between self-report and objective measures of driving behavior. Searches were undertaken in the following electronic databases, PsycINFO, PubMed, and Scopus, for peer-reviewed full-text articles that (1) focused on road safety, and (2) compared both subjective and objective measures of driving performance or driver safety. A total of 22,728 articles were identified, with 19 articles, comprising 20 studies, included as part of the review. The research reported herein suggested that for some behaviors (e.g., driving in stressful situations) there were similarities between self-report and objective measures while for other behaviors (e.g., sleepiness and vigilance states) there were differences between these measurement techniques. In addition, findings from some studies suggested that in-vehicle devices may be a valid measurement tool to assess driving exposure in older drivers. Further research is needed to examine the correspondence between self-report and objective measures of driving behavior. In particular, there is a need to increase the number of studies which compare "like with like" as it is difficult to draw comparisons when there are variations in measurement tools used. Incorporating a range of objective and self-report measurements tools in research would help to ensure that the methods used offer the most reliable measures of assessing on-road behaviors. Crown Copyright © 2018. Published by Elsevier Ltd. All rights reserved.

Disruptions in Functional Network Connectivity during Alcohol Intoxicated Driving

PubMed Central

Rzepecki-Smith, Catherine I.; Meda, Shashwath A.; Calhoun, Vince D.; Stevens, Michael C.; Jafri, Madiha J.; Astur, Robert S.; Pearlson, Godfrey D.

2009-01-01

Background: Driving while under the influence of alcohol is a major public health problem whose neural basis is not well understood. In a recently published fMRI study (Meda et al, 2009), our group identified five, independent critical driving-associated brain circuits whose inter-regional connectivity was disrupted by alcohol intoxication. However, the functional connectivity between these circuits has not yet been explored in order to determine how these networks communicate with each other during sober and alcohol-intoxicated states. Methods: In the current study, we explored such differences in connections between the above brain circuits and driving behavior, under the influence of alcohol versus placebo. Forty social drinkers who drove regularly underwent fMRI scans during virtual reality driving simulations following two alcohol doses, placebo and an individualized dose producing blood alcohol concentrations (BACs) of 0.10%. Results: At the active dose, we found specific disruptions of functional network connectivity between the frontal-temporal-basal ganglia and the cerebellar circuits. The temporal connectivity between these two circuits was found to be less correlated (p <0.05) when driving under the influence of alcohol. This disconnection was also associated with an abnormal driving behavior (unstable motor vehicle steering). Conclusions: Connections between frontal-temporal-basal ganglia and cerebellum have recently been explored; these may be responsible in part for maintaining normal motor behavior by integrating their overlapping motor control functions. These connections appear to be disrupted by alcohol intoxication, in turn associated with an explicit type of impaired driving behavior. PMID:20028354

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.

Mean PB To Failure - Initial results from a long-term study of disk storage patterns at the RACF

NASA Astrophysics Data System (ADS)

Caramarcu, C.; Hollowell, C.; Rao, T.; Strecker-Kellogg, W.; Wong, A.; Zaytsev, S. A.

2015-12-01

The RACF (RHIC-ATLAS Computing Facility) has operated a large, multi-purpose dedicated computing facility since the mid-1990’s, serving a worldwide, geographically diverse scientific community that is a major contributor to various HEPN projects. A central component of the RACF is the Linux-based worker node cluster that is used for both computing and data storage purposes. It currently has nearly 50,000 computing cores and over 23 PB of storage capacity distributed over 12,000+ (non-SSD) disk drives. The majority of the 12,000+ disk drives provide a cost-effective solution for dCache/XRootD-managed storage, and a key concern is the reliability of this solution over the lifetime of the hardware, particularly as the number of disk drives and the storage capacity of individual drives grow. We report initial results of a long-term study to measure lifetime PB read/written to disk drives in the worker node cluster. We discuss the historical disk drive mortality rate, disk drive manufacturers' published MPTF (Mean PB to Failure) data and how they are correlated to our results. The results help the RACF understand the productivity and reliability of its storage solutions and have implications for other highly-available storage systems (NFS, GPFS, CVMFS, etc) with large I/O requirements.

Assessment of Driving Safety in Older Adults with Mild Cognitive Impairment.

PubMed

Anstey, Kaarin J; Eramudugolla, Ranmalee; Chopra, Sidhant; Price, Jasmine; Wood, Joanne M

2017-01-01

With population aging, drivers with mild cognitive impairment (MCI) are increasing; however, there is little evidence available regarding their safety. We aimed to evaluate risk of unsafe on-road driving performance among older adults with MCI. The study was a cross-sectional observational study, set in Canberra, Australia. Participants were non-demented, current drivers (n = 302) aged 65 to 96 years (M = 75.7, SD = 6.18, 40% female) recruited through the community and primary and tertiary care clinics. Measures included a standardized on-road driving test (ORT), a battery of screening measures designed to evaluate older driver safety (UFOV®, DriveSafe, Multi-D), a neurocognitive test battery, and questionnaires on driving history and behavior. Using Winblad criteria, 57 participants were classified as having MCI and 245 as cognitively normal (CN). While the MCI group had a significantly lower overall safety rating on the ORT (5.61 versus 6.05, p = 0.03), there was a wide range of driving safety scores in the CN and MCI groups. The MCI group performed worse than the CN group on the off-road screening tests. The best fitting model of predictors of ORT performance across the combined sample included age, the Multi-D, and DriveSafe, classifying 90.4% of the sample correctly. Adults with MCI exhibit a similar range of driving ability to CN adults, although on average they scored lower on off-road and on-road assessments. Driving specific tests were more strongly associated with safety ratings than traditional neuropsychological tests.

Assessment of Driving Safety in Older Adults with Mild Cognitive Impairment

PubMed Central

Anstey, Kaarin J.; Eramudugolla, Ranmalee; Chopra, Sidhant; Price, Jasmine; Wood, Joanne M.

2017-01-01

Background: With population aging, drivers with mild cognitive impairment (MCI) are increasing; however, there is little evidence available regarding their safety. Objective: We aimed to evaluate risk of unsafe on-road driving performance among older adults with MCI. Method: The study was a cross-sectional observational study, set in Canberra, Australia. Participants were non-demented, current drivers (n = 302) aged 65 to 96 years (M = 75.7, SD = 6.18, 40% female) recruited through the community and primary and tertiary care clinics. Measures included a standardized on-road driving test (ORT), a battery of screening measures designed to evaluate older driver safety (UFOV®, DriveSafe, Multi-D), a neurocognitive test battery, and questionnaires on driving history and behavior. Results: Using Winblad criteria, 57 participants were classified as having MCI and 245 as cognitively normal (CN). While the MCI group had a significantly lower overall safety rating on the ORT (5.61 versus 6.05, p = 0.03), there was a wide range of driving safety scores in the CN and MCI groups. The MCI group performed worse than the CN group on the off-road screening tests. The best fitting model of predictors of ORT performance across the combined sample included age, the Multi-D, and DriveSafe, classifying 90.4% of the sample correctly. Conclusion: Adults with MCI exhibit a similar range of driving ability to CN adults, although on average they scored lower on off-road and on-road assessments. Driving specific tests were more strongly associated with safety ratings than traditional neuropsychological tests. PMID:28372333

Agreements between ground-based and satellite-based observations. [of earth magnetospheric currents

NASA Technical Reports Server (NTRS)

Akasofu, S.-I.; Weimer, D.; Iijima, T.; Ahn, B.-H.; Kamide, Y.

1990-01-01

The polar ionospheric parameters obtained by the meridian chain of magnetometers are compared with those obtained by satellites, and a number of ionospheric quantities including the distribution of the electric potential, field-aligned currents, ionospheric currents and their equatorial counterparts, and the relationship between the AE index and the cross-polar cap potential is determined. It is noted that the agreement observed between the ground-based and satellite-based results allows to reduce the search for the driving mechanism of the ionospheric Pedersen current to identifying the driving mechanism of the Pedersen counterpart current in the equatorial plane.

Relative Advantages of Direct and Indirect Drive for an Inertial Fusion Energy Power Plant Driven by a Diode-Pumped Solid-State Laser

NASA Astrophysics Data System (ADS)

Orth, C. D.

2001-03-01

This paper reviews our current understanding of the relative advantages of direct drive (DD) and indirect drive (ID) for a 1 GWe inertial fusion energy (IFE) power plant driven by a diode-pumped solid-state laser (DPSSL). This comparison is motivated by a recent study (1) that shows that the projected cost of electricity (COE) for DD is actually about the same as that for ID even though the target gain for DD can be much larger. We can therefore no longer assume that DD is the ultimate targeting scenario for IFE, and must begin a more rigorous comparison of these two drive options. The comparison begun here shows that ID may actually end up being preferred, but the uncertainties are still rather large.

Self-compassion in the face of shame and body image dissatisfaction: implications for eating disorders.

PubMed

Ferreira, Cláudia; Pinto-Gouveia, José; Duarte, Cristiana

2013-04-01

The current study examines the role of self-compassion in face of shame and body image dissatisfaction, in 102 female eating disorders' patients, and 123 women from general population. Self-compassion was negatively associated with external shame, general psychopathology, and eating disorders' symptomatology. In women from the general population increased external shame predicted drive for thinness partially through lower self-compassion; also, body image dissatisfaction directly predicted drive for thinness. However, in the patients' sample increased shame and body image dissatisfaction predicted increased drive for thinness through decreased self-compassion. These results highlight the importance of the affiliative emotion dimensions of self-compassion in face of external shame, body image dissatisfaction and drive for thinness, emphasising the relevance of cultivating a self-compassionate relationship in eating disorders' patients. Copyright © 2013. Published by Elsevier Ltd.

Improving driving advice provided to cardiology patients on discharge

PubMed Central

Vusirikala, Amoolya; Backhouse, Mark; Schimansky, Sarah

2018-01-01

Certain cardiac conditions can limit patients’ ability to drive. It remains the doctors' responsibility to advise patients of any driving restrictions and is particularly important after certain diagnoses or procedures. We identified that the quality of documented advice was variable and frequently no written driving advice was recorded on discharge. It was apparent that there was a lack of awareness and knowledge of the current Driving and Vehicle Licensing Agency (DVLA) guidance among junior doctors. We therefore designed a quality improvement project using Plan–Do–Study–Act (PDSA) methodology to improve the provision of driving advice on discharge from a cardiology ward by focusing on staff education. After collecting baseline data, we created a template with cardiology-specific DVLA advice. During the second PDSA cycle, we improved the electronic template and also introduced a hard copy on the ward. During the third PDSA cycle, we incorporated information on DVLA guidance in the specialty induction session. We also evaluated junior doctors’ confidence of providing driving advice before and after this intervention. Baseline measurements showed that 10% (9/92) of all discharge summaries included driving advice. This improved to 49% (34/69) after the third PDSA cycle. Importantly, after receiving information on driving advice in the induction, junior doctors felt more confident in providing driving advice to cardiology patients on discharge. In conclusion, the provision of driving advice on discharge is an important element of patient safety. However, clinicians’ knowledge and awareness of current DVLA guidance is often limited. We demonstrated a significant increase in the provision of driving advice by introducing a standardised template. PMID:29610769

3D model of a matrix source of negative ions: RF driving by a large area planar coil

NASA Astrophysics Data System (ADS)

Demerdzhiev, A.; Lishev, St.; Tarnev, Kh.; Shivarova, A.

2015-04-01

Based on three-dimensional (3D) modeling, different manners of a planar-coil inductive discharge driving of a plasma source completed as a matrix of small-radius hydrogen discharges are studied regarding a proper choice of an efficient and alike rf power deposition into the separate discharges of the matrix. Driving the whole matrix by a single coil and splitting it to blocks of discharge tubes, with single coil driving of each block, are the two cases considered. The results from the self-consistent model presented for a block of discharge tubes show its reliability in ensuring the same spatial distribution of the plasma parameters in the discharges completing the block. Since regarding the construction of the matrix, its driving as a whole by a single coil is the most reasonable decision, three modifications of the coil design have been tested: two zigzag coils with straight conductors passing, respectively, between and through the bottoms of the discharge tubes and a coil with an "omega" shaped conductor on the bottom of each tube. Among these three configurations, the latter ‒ a coil with an Ω-shaped conductor on the bottom of each tube ‒ shows up with the highest rf efficiency of an inductive discharge driving, shown by results for the rf current induced in the discharges obtained from an electrodynamical description. In all the cases considered the spatial distribution of the induced current density is analysed based on the manner of the penetration into the plasma of the wave field sustaining the inductive discharges.

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.

An assembly-type master-slave catheter and guidewire driving system for vascular intervention.

PubMed

Cha, Hyo-Jeong; Yi, Byung-Ju; Won, Jong Yun

2017-01-01

Current vascular intervention inevitably exposes a large amount of X-ray to both an operator and a patient during the procedure. The purpose of this study is to propose a new catheter driving system which assists the operator in aspects of less X-ray exposure and convenient user interface. For this, an assembly-type 4-degree-of-freedom master-slave system was designed and tested to verify the efficiency. First, current vascular intervention procedures are analyzed to develop a new robotic procedure that enables us to use conventional vascular intervention devices such as catheter and guidewire which are commercially available in the market. Some parts of the slave robot which contact the devices were designed to be easily assembled and dissembled from the main body of the slave robot for sterilization. A master robot is compactly designed to conduct insertion and rotational motion and is able to switch from the guidewire driving mode to the catheter driving mode or vice versa. A phantom resembling the human arteries was developed, and the master-slave robotic system is tested using the phantom. The contact force of the guidewire tip according to the shape of the arteries is measured and reflected to the user through the master robot during the phantom experiment. This system can drastically reduce radiation exposure by replacing human effort by a robotic system for high radiation exposure procedures. Also, benefits of the proposed robot system are low cost by employing currently available devices and easy human interface.

Inter-hemispheric electroencephalography coherence analysis: assessing brain activity during monotonous driving.

PubMed

Jap, Budi Thomas; Lal, Sara; Fischer, Peter

2010-06-01

The current study investigated the effect of monotonous driving on inter-hemispheric electroencephalography (EEG) coherence. Twenty-four non-professional drivers were recruited to perform a fatigue instigating monotonous driving task while 30 channels of EEG were simultaneously recorded. The EEG recordings were then divided into 5 equal sections over the entire driving period for analysis. Inter-hemispheric coherence was computed from 5 homologous EEG electrode pairs (FP1-FP2, C3-C4, T7-T8, P7-P8, and O1-O2) for delta, theta, alpha and beta frequency bands. Results showed that frontal and occipital inter-hemispheric coherence values were significantly higher than central, parietal, and temporal sites for all four frequency bands (p<0.0001). In the alpha frequency band, significant difference was found between earlier and later driving sections (p=0.02). The coherence values in all EEG frequency bands were slightly increased at the end of the driving session, except for FP1-FP2 electrode pair, which showed no significant change in coherence in the beta frequency band at the end of the driving session. Copyright 2010 Elsevier B.V. All rights reserved.

Alternative Shapes and Shaping Techniques for Enhanced Transformer Ratios in Beam Driven Techniques

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

Lemery, F.; Piot, P.

The transformer ration of collinear beam-driven techniques can be significantly improved by shaping the current profile of the drive bunch. To date, several current shapes have been proposed to increase the transformer ratio and produce quasi-uniform energy loss within the drive bunch. Some of these tailoring techniques are possible as a results of recent beam-dynamics advances, e.g., transverse-to-longitudinal emittance exchanger. In ths paper, we propose an alternative class of longitudinal shapes that enable high transformer ratio and uniform energy loss across the drive bunch. We also suggest a simple method based on photocathode-laser shaping and passive shaping in wakefield structuremore » to realize shape close to the theoretically optimized current profiles.« less

Driving while alcohol impaired : a preliminary exploration of the issues and possible approaches.

DOT National Transportation Integrated Search

1989-01-01

Under current Virginia law, a driver who has been drinking but does not have a BAC of 0.10% will likely not be arrested even if his/her driving ability is visibly impaired. A "driving while alcohol impaired" (DWAI) statute would provide law enforceme...

Development of a National Item Bank for Tests of Driving Knowledge.

ERIC Educational Resources Information Center

Pollock, William T.; McDole, Thomas L.

Materials intended for driving knowledge test development use by operational licensing and education agencies were prepared. Candidate test items were developed, using literature and operational practice sources, to reflect current state-of-knowledge with respect to principles of safe, efficient driving, to legal regulations, and to traffic…

Drivers’ Visual Characteristics when Merging onto or Exiting an Urban Expressway

PubMed Central

Cheng, Ying; Gao, Li; Zhao, Yanan; Du, Feng

2016-01-01

The aim of this study is to examine drivers’ visual and driving behavior while merging onto or exiting an urban expressway with low and high traffic densities. The analysis was conducted according to three periods (approaching, merging or exiting, and accelerating or decelerating). A total of 10 subjects (8 males and 2 females) with ages ranging from 25 to 52 years old (M = 30.0 years old) participated in the study. The research was conducted in a natural driving situation, and the drivers’ eye movements were monitored and recorded using an eye tracking system. The results show that the influence of traffic density on the glance duration and scan duration is more significant when merging than when exiting. The results also demonstrate that the number of glances and the mean glance duration are mainly related to the driving task (e.g., the merging period). Therefore, drivers’ visual search strategies mainly depend on the current driving task. With regard to driving behavior, the variation tendencies of the duration and the velocity of each period are similar. These results support building an automated driving assistant system that can automatically identify gaps and accelerate or decelerate the car accordingly or provide suggestions to the driver to do so. PMID:27657888

Benzodiazepines, opioids and driving: an overview of the experimental research.

PubMed

Leung, Stefanie Y

2011-05-01

Road crashes contribute significantly to the total burden of injury in Australia, with the risk of injury being associated with the presence of drugs and/or alcohol in the driver's blood. Increasingly, some of the most commonly detected drugs include prescription medicines, the most notable of these being benzodiazepines and opioids. However, there is a paucity of experimental research into the effects of prescribed psychoactive drugs on driving behaviours. This paper provides an overview of experimental studies investigating the effects of prescribed doses of benzodiazepines and opioids on driving ability, and points to future directions for research. There is growing epidemiological evidence linking the therapeutic use of benzodiazepines and opioids to an increased crash risk. However, the current experimental literature remains unclear. Limitations to study methodologies have resulted in inconsistent findings. Limited experimental evidence exists to inform policy and guidelines regarding fitness-to-drive for patients taking prescribed benzodiazepines and opioids. Further experimental research is required to elucidate the effects of these medications on driving, under varying conditions and in different medical contexts. This will ensure that doctors prescribing benzodiazepines and opioids are well informed, and can appropriately advise patients of the risks associated with driving whilst taking these medications. © 2011 Australasian Professional Society on Alcohol and other Drugs.

Effects on driving performance of interacting with an in-vehicle music player: a comparison of three interface layout concepts for information presentation.

PubMed

Mitsopoulos-Rubens, Eve; Trotter, Margaret J; Lenné, Michael G

2011-05-01

Interface design is an important factor in assessing the potential effects on safety of interacting with an in-vehicle information system while driving. In the current study, the layout of information on a visual display was manipulated to explore its effect on driving performance in the context of music selection. The comparative effects of an auditory-verbal (cognitive) task were also explored. The driving performance of 30 participants was assessed under both baseline and dual task conditions using the Lane Change Test. Concurrent completion of the music selection task with driving resulted in significant impairment to lateral driving performance (mean lane deviation and percentage of correct lane changes) relative to the baseline, and significantly greater mean lane deviation relative to the combined driving and the cognitive task condition. The magnitude of these effects on driving performance was independent of layout concept, although significant differences in subjective workload estimates and performance on the music selection task across layout concepts highlights that potential uncertainty regarding design use as conveyed through layout concept could be disadvantageous. The implications of these results for interface design and safety are discussed. Copyright © 2010 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Study of the choice of the decoupling layout for the ITER ICRH system

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

Vervier, M., E-mail: michel.vervier@rma.ac.be; Messiaen, A.; Ongena, J.

10 decouplers are used to neutralize the mutual coupling effects and to control the current amplitude of the 24 straps array of the ITER ICRH antenna in the case of current drive phasing. In the case of heating phasing only 4 decouplers are active and the array current control needs to act on the ratio between the power delivered by the 4 generators. This ratio is very sensitive to the precise adjustment of the antenna array phasing. The maximum total radiated power capability is then limited when the power of one generator reaches its maximum value. With the addition ofmore » four switches all 10 installed decouplers are made active and can act on all mutual coupling effects with equal source power from the 4 generators. With four more switches the current drive phasing could work with a reduced poloidal phasing resulting in a 35% increase of its coupling to the plasma.« less

Current drive with combined electron cyclotron wave and high harmonic fast wave in tokamak plasmas

NASA Astrophysics Data System (ADS)

Li, J. C.; Gong, X. Y.; Dong, J. Q.; Wang, J.; Zhang, N.; Zheng, P. W.; Yin, C. Y.

2016-12-01

The current driven by combined electron cyclotron wave (ECW) and high harmonic fast wave is investigated using the GENRAY/CQL3D package. It is shown that no significant synergetic current is found in a range of cases with a combined ECW and fast wave (FW). This result is consistent with a previous study [Harvey et al., in Proceedings of IAEA TCM on Fast Wave Current Drive in Reactor Scale Tokamaks (Synergy and Complimentarily with LHCD and ECRH), Arles, France, IAEA, Vienna, 1991]. However, a positive synergy effect does appear with the FW in the lower hybrid range of frequencies. This positive synergy effect can be explained using a picture of the electron distribution function induced by the ECW and a very high harmonic fast wave (helicon). The dependence of the synergy effect on the radial position of the power deposition, the wave power, the wave frequency, and the parallel refractive index is also analyzed, both numerically and physically.

Drinking-driving attitudes: a survey of Fairfax County.

DOT National Transportation Integrated Search

1973-01-01

The objective of this study was to gather and tabulate baseline data on selected attitudes and opinions held by the public of Fairfax County, Virginia. The study was designed to assist the program of the Alcohol Safety Action Project, currently in op...

Current distribution in tissues with conducted electrical weapons operated in drive-stun mode.

PubMed

Panescu, Dorin; Kroll, Mark W; Brave, Michael

2016-08-01

The TASER® conducted electrical weapon (CEW) is best known for delivering electrical pulses that can temporarily incapacitate subjects by overriding normal motor control. The alternative drive-stun mode is less understood and the goal of this paper is to analyze the distribution of currents in tissues when the CEW is operated in this mode. Finite element modeling (FEM) was used to approximate current density in tissues with boundary electrical sources placed 40 mm apart. This separation was equivalent to the distance between drive-stun mode TASER X26™, X26P, X2 CEW electrodes located on the device itself and between those located on the expended CEW cartridge. The FEMs estimated the amount of current flowing through various body tissues located underneath the electrodes. The FEM simulated the attenuating effects of both a thin and of a normal layer of fat. The resulting current density distributions were used to compute the residual amount of current flowing through deeper layers of tissue. Numerical modeling estimated that the skin, fat and skeletal muscle layers passed at least 86% or 91% of total CEW current, assuming a thin or normal fat layer thickness, respectively. The current density and electric field strength only exceeded thresholds which have increased probability for ventricular fibrillation (VFTJ), or for cardiac capture (CCTE), in the skin and the subdermal fat layers. The fat layer provided significant attenuation of drive-stun CEW currents. Beyond the skeletal muscle layer, only fractional amounts of the total CEW current were estimated to flow. The regions presenting risk for VF induction or for cardiac capture were well away from the typical heart depth.

Ion Heating During Local Helicity Injection Plasma Startup in the Pegasus ST

NASA Astrophysics Data System (ADS)

Burke, M. G.; Barr, J. L.; Bongard, M. W.; Fonck, R. J.; Hinson, E. T.; Perry, J. M.; Reusch, J. A.

2015-11-01

Plasmas in the Pegasus ST are initiated either through standard, MHD stable, inductive current drive or non-solenoidal local helicity injection (LHI) current drive with strong reconnection activity, providing a rich environment to study ion dynamics. During LHI discharges, a large amount of impurity ion heating has been observed, with the passively measured impurity Ti as high as 800 eV compared to Ti ~ 60 eV and Te ~ 175 eV during standard inductive current drive discharges. In addition, non-thermal ion velocity distributions are observed and appear to be strongest near the helicity injectors. The ion heating is hypothesized to be a result of large-scale magnetic reconnection activity, as the amount of heating scales with increasing fluctuation amplitude of the dominant, edge localized, n =1 MHD mode. An approximate temporal scaling of the heating with the amplitude of higher frequency magnetic fluctuations has also been observed, with large amounts of power spectral density present at several impurity ion cyclotron frequencies. Recent experiments have focused on investigating the impurity ion heating scaling with the ion charge to mass ratio as well as the reconnecting field strength. The ion charge to mass ratio was modified by observing different impurity charge states in similar LHI plasmas while the reconnecting field strength was modified by changing the amount of injected edge current. Work supported by US DOE grant DE-FG02-96ER54375.

Measurements of dynamo effect on double-CHI pulse ST plasmas on HIST

NASA Astrophysics Data System (ADS)

Ito, K.; Hanao, T.; Ishihara, M.; Matsumoto, K.; Higashi, T.; Kikuchi, Y.; Fukumoto, N.; Nagata, M.

2011-10-01

Coaxial Helicity injection (CHI) is an efficient current-drive method used in spheromak and spherical torus (ST) experiments. An anticipated issue for CHI is achieving good energy confinement, since it relies on the magnetic relaxation and dynamo. This is essentially because CHI cannot drive a dynamo directly inside a closed magnetic flux surface. Thus, it is an important issue to investigate dynamo effect to explore CHI current drive mechanisms in a new approach such as Multi-pulsing CHI method. To study the dynamo model with two-fluid Hall effects, we have started from the generalized Ohm law. We have measured each MHD dynamo term and Hall dynamo term separately by using Mach probe and Hall probe involving 3-axis magnetic pick-up coils. The result shows that the induced electric field due to MHD dynamo is large enough to sustain the mean toroidal current against resistive decay in the core region. In the other hand, the anti-dynamo effect in the MHD dynamo term is observed in the central open flux column (OFC) region. From the viewpoint of two-fluid theory, ion diamagnetic drift is opposite to the electron diamagnetic drift, maybe resulting in the anti-dynamo effect. Hall dynamo may arise from the fluctuating electron diamagnetic current due to high electron density gradient which is large in the OFC region.

The traffic climate in China: The mediating effect of traffic safety climate between personality and dangerous driving behavior.

PubMed

Zhang, Qian; Ge, Yan; Qu, Weina; Zhang, Kan; Sun, Xianghong

2018-04-01

Traffic safety climate is defined as road users' attitudes and perceptions of traffic in a specific context at a given point in time. The current study aimed to validate the Chinese version of the Traffic Climate Scale (TCS) and to explore its relation to drivers' personality and dangerous driving behavior. A sample of 413 drivers completed the Big Five Inventory (BFI), the Chinese version of the TCS, the Dula Dangerous Driving Index (DDDI) and a demographic questionnaire. Exploratory factor analysis and confirmatory factor analysis were performed to confirm a three-factor (external affective demands, internal requirements and functionality) solution of the TCS. The reliability and validity of the Chinese version of TCS were verified. More importantly, the results showed that the effect of personality on dangerous driving behavior was mediated by traffic climate. Specifically, the functionality of the TCS mediated the effect of neuroticism on negative cognitive/emotional driving and drunk driving, while openness had an indirect impact on aggressive driving, risky driving and drunk driving based on the internal requirements of the TCS. Additionally, agreeableness had a negative direct impact on four factors of the DDDI, while neuroticism had a positive direct impact on negative cognitive/emotional driving, drunk driving and risky driving. In conclusion, the Chinese version of the TCS will be useful to evaluate drivers' attitudes towards and perceptions of the requirements of traffic environment in which they participate and will also be valuable for comparing traffic cultures and environments in different countries. Copyright © 2018 Elsevier Ltd. All rights reserved.

Teens' distracted driving behavior: Prevalence and predictors.

PubMed

Gershon, Pnina; Zhu, Chunming; Klauer, Sheila G; Dingus, Tom; Simons-Morton, Bruce

2017-12-01

Teen drivers' over-involvement in crashes has been attributed to a variety of factors, including distracted driving. With the rapid development of in-vehicle systems and portable electronic devices, the burden associated with distracted driving is expected to increase. The current study identifies predictors of secondary task engagement among teenage drivers and provides basis for interventions to reduce distracted driving behavior. We described the prevalence of secondary tasks by type and driving conditions and evaluated the associations between the prevalence of secondary task engagement, driving conditions, and selected psychosocial factors. The private vehicles of 83 newly-licensed teenage drivers were equipped with Data Acquisition Systems (DAS), which documented driving performance measures, including secondary task engagement and driving environment characteristics. Surveys administered at licensure provided psychosocial measures. Overall, teens engaged in a potentially distracting secondary task in 58% of sampled road clips. The most prevalent types of secondary tasks were interaction with a passenger, talking/singing (no passenger), external distraction, and texting/dialing the cell phone. Secondary task engagement was more prevalent among those with primary vehicle access and when driving alone. Social norms, friends' risky driving behaviors, and parental limitations were significantly associated with secondary task prevalence. In contrast, environmental attributes, including lighting and road surface conditions, were not associated with teens' engagement in secondary tasks. Our findings indicated that teens engaged in secondary tasks frequently and poorly regulate their driving behavior relative to environmental conditions. Practical applications: Peer and parent influences on secondary task engagement provide valuable objectives for countermeasures to reduce distracted driving among teenage drivers. Copyright © 2017 National Safety Council and Elsevier Ltd. All rights reserved.

Driving poststroke: problem identification, assessment use, and interventions offered by canadian occupational therapists.

PubMed

Petzold, Anita; Korner-Bitensky, Nicol; Rochette, Annie; Teasell, Robert; Marshall, Shawn; Perrier, Marie-Josee

2010-01-01

Driving is a key factor in maintaining autonomy and participation in life. Occupational therapists (OTs) are expected to assess individuals who want to resume driving post stroke and to provide retraining where appropriate. Research from the 1980s and 1990s indicated that patients were, for the most part, not being assessed and retrained. However, little is known about current practice management. Thus, this study examined clinicians' management of driving-related issues when treating clients with stroke. We performed a Canadawide telephone survey of 480 OTs providing stroke rehabilitation in both inpatient rehabilitation and community-based settings. Clinicians reported on problems they noted and assessments and interventions they would provide for a "typical patient" described in a vignette that matched their work setting. 20% and 34% of clinicians responding to the inpatient rehabilitation and community-based vignettes, respectively, identified return to driving as a problem. Clinician and work environment variables significantly associated (P < .01) with identifying driving as a potential problem included being male, involvement in university teaching, research conducted in setting, and hosting student placements. The use of driving-specific assessments was under 12%. Less than 6% of clinicians offered driving retraining, and their desired use of retraining was low. Few clinicians identified driving as a problem post stoke, raising concern that patients attempt to drive on their own or never resume driving because of a lack of attention to driving during their rehabilitation. Poststroke driver assessment and retraining is a critical component of poststroke community reintegration that requires greater awareness by clinicians.

Current drive at plasma densities required for thermonuclear reactors.

PubMed

Cesario, R; Amicucci, L; Cardinali, A; Castaldo, C; Marinucci, M; Panaccione, L; Santini, F; Tudisco, O; Apicella, M L; Calabrò, G; Cianfarani, C; Frigione, D; Galli, A; Mazzitelli, G; Mazzotta, C; Pericoli, V; Schettini, G; Tuccillo, A A

2010-08-10

Progress in thermonuclear fusion energy research based on deuterium plasmas magnetically confined in toroidal tokamak devices requires the development of efficient current drive methods. Previous experiments have shown that plasma current can be driven effectively by externally launched radio frequency power coupled to lower hybrid plasma waves. However, at the high plasma densities required for fusion power plants, the coupled radio frequency power does not penetrate into the plasma core, possibly because of strong wave interactions with the plasma edge. Here we show experiments performed on FTU (Frascati Tokamak Upgrade) based on theoretical predictions that nonlinear interactions diminish when the peripheral plasma electron temperature is high, allowing significant wave penetration at high density. The results show that the coupled radio frequency power can penetrate into high-density plasmas due to weaker plasma edge effects, thus extending the effective range of lower hybrid current drive towards the domain relevant for fusion reactors.

Method for producing silicon thin-film transistors with enhanced forward current drive

DOEpatents

Weiner, K.H.

1998-06-30

A method is disclosed for fabricating amorphous silicon thin film transistors (TFTs) with a polycrystalline silicon surface channel region for enhanced forward current drive. The method is particularly adapted for producing top-gate silicon TFTs which have the advantages of both amorphous and polycrystalline silicon TFTs, but without problem of leakage current of polycrystalline silicon TFTs. This is accomplished by selectively crystallizing a selected region of the amorphous silicon, using a pulsed excimer laser, to create a thin polycrystalline silicon layer at the silicon/gate-insulator surface. The thus created polysilicon layer has an increased mobility compared to the amorphous silicon during forward device operation so that increased drive currents are achieved. In reverse operation the polysilicon layer is relatively thin compared to the amorphous silicon, so that the transistor exhibits the low leakage currents inherent to amorphous silicon. A device made by this method can be used, for example, as a pixel switch in an active-matrix liquid crystal display to improve display refresh rates. 1 fig.

Method for producing silicon thin-film transistors with enhanced forward current drive

DOEpatents

Weiner, Kurt H.

1998-01-01

A method for fabricating amorphous silicon thin film transistors (TFTs) with a polycrystalline silicon surface channel region for enhanced forward current drive. The method is particularly adapted for producing top-gate silicon TFTs which have the advantages of both amorphous and polycrystalline silicon TFTs, but without problem of leakage current of polycrystalline silicon TFTs. This is accomplished by selectively crystallizing a selected region of the amorphous silicon, using a pulsed excimer laser, to create a thin polycrystalline silicon layer at the silicon/gate-insulator surface. The thus created polysilicon layer has an increased mobility compared to the amorphous silicon during forward device operation so that increased drive currents are achieved. In reverse operation the polysilicon layer is relatively thin compared to the amorphous silicon, so that the transistor exhibits the low leakage currents inherent to amorphous silicon. A device made by this method can be used, for example, as a pixel switch in an active-matrix liquid crystal display to improve display refresh rates.

Gate drive latching circuit for an auxiliary resonant commutation circuit

NASA Technical Reports Server (NTRS)

Delgado, Eladio Clemente (Inventor); Kheraluwala, Mustansir Hussainy (Inventor)

1999-01-01

A gate drive latching circuit for an auxiliary resonant commutation circuit for a power switching inverter includes a current monitor circuit providing a current signal to a pair of analog comparators to implement latching of one of a pair of auxiliary switching devices which are used to provide commutation current for commutating switching inverters in the circuit. Each of the pair of comparators feeds a latching circuit which responds to an active one of the comparators for latching the associated gate drive circuit for one of the pair of auxiliary commutating switches. An initial firing signal is applied to each of the commutating switches to gate each into conduction and the resulting current is monitored to determine current direction and therefore the one of the switches which is carrying current. The comparator provides a latching signal to the one of the auxiliary power switches which is actually conducting current and latches that particular power switch into an on state for the duration of current through the device. The latching circuit is so designed that the only time one of the auxiliary switching devices can be latched on is during the duration of an initial firing command signal.

Shear Alfven Wave Injection in the Magnetosphere by Ionospheric Modifications in the Absence of Electrojet Currents

NASA Astrophysics Data System (ADS)

Papadopoulos, K.; Eliasson, B.; Shao, X.; Labenski, J.; Chang, C.

2011-12-01

A new concept of generating ionospheric currents in the ULF/ELF range with modulated HF heating using ground-based transmitters even in the absence of electrojet currents is presented. The new concept relies on using HF heating of the F-region to modulate the electron temperature and has been given the name Ionospheric Current Drive (ICD). In ICD, the pressure gradient associated with anomalous or collisional F-region electron heating drives a local diamagnetic current that acts as an antenna to inject mainly Magneto-Sonic (MS) waves in the ionospheric plasma. The electric field associated with the MS wave drives Hall currents when it reaches the E region of the ionosphere. The Hall currents act as a secondary antenna that inject waves in the Earth-Ionosphere Waveguide (EIW) below and shear Alfven waves or EMIC waves upwards towards the conjugate regions. The paper presents: (i) Theoretical results using a cold Hall MHD model to study ICD and the generation of ULF/ELF waves by the modulation of the electron pressure at the F2-region with an intense HF electromagnetic wave. The model solves equations governing the dynamics of the shear Alfven and magnetosonic modes, of the damped modes in the diffusive Pedersen layer, and of the weakly damped helicon wave mode in the Hall-dominated E-region. The model incorporates realistic profile of the ionospheric conductivities and magnetic field configuration. We use the model to simulate propagation and dynamics of the low-frequency waves and their injection into the magnetosphere from the HAARP and Arecibo ionospheric heaters. (ii) Proof of principle experiments using the HAARP ionospheric heater in conjunction with measurements by the DEMETER satellite This work is supported by ONR MURI grant and DARPA BRIOCHE Program

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.

Robust current control-based generalized predictive control with sliding mode disturbance compensation for PMSM drives.

PubMed

Liu, Xudong; Zhang, Chenghui; Li, Ke; Zhang, Qi

2017-11-01

This paper addresses the current control of permanent magnet synchronous motor (PMSM) for electric drives with model uncertainties and disturbances. A generalized predictive current control method combined with sliding mode disturbance compensation is proposed to satisfy the requirement of fast response and strong robustness. Firstly, according to the generalized predictive control (GPC) theory based on the continuous time model, a predictive current control method is presented without considering the disturbance, which is convenient to be realized in the digital controller. In fact, it's difficult to derive the exact motor model and parameters in the practical system. Thus, a sliding mode disturbance compensation controller is studied to improve the adaptiveness and robustness of the control system. The designed controller attempts to combine the merits of both predictive control and sliding mode control, meanwhile, the controller parameters are easy to be adjusted. Lastly, the proposed controller is tested on an interior PMSM by simulation and experiment, and the results indicate that it has good performance in both current tracking and disturbance rejection. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

A Modelling Study of the Coastal Current in the Northwestern South China Sea: Response to Strong and Weak Southwest Monsoon

NASA Astrophysics Data System (ADS)

Ding, Y.; Yu, J.; Bao, X.; Yao, Z.

2016-02-01

The characteristics and dynamical mechanism of summer-time coastal current over the northwestern South China Sea (NSCS) shelf have been investigated based on a high resolution unstructured-grid finite volume community ocean model (FVCOM). Model-data comparison demonstrates that model well resolves the coastal dynamics over the NSCS shelf. The coastal current on the NSCS shelf is intensively influenced by monsoon and freshwater discharge of the Pearl River. Strong southwesterly wind drive the coastal current northeastward. However, under weak southwest monsoon, the coastal current west of Pearl River estuary (PRE) advects toward southwest, and splits into two parts when reaching east of the Qiongzhou Strait, with one branch entering the Gulf of Tonkin through the Qiongzhou Strait, transporting low salinity water into the Gulf of Tonkin, and the other part flows cyclonic and interacts with the northeastward current around southeast of Hainan Island, forming a cyclonic eddy east of the Qiongzhou Strait. A variety of model experiments focused on freshwater discharge, wind forcing, tidal rectification, and stratification are performed to study the physical mechanism of the southwestward coastal current which is usually against the summer wind. Process-oriented experiment results indicate that the southwest monsoon and freshwater discharge are important factors influencing the formation of southwestward coastal current during summer. Momentum balance analysis suggests that the along shelf barotropic pressure gradient due to the Pearl River discharge and wind forcing provides the main driving force for the southwestward coastal current.

Self-rated driving and driving safety in older adults.

PubMed

Ross, Lesley A; Dodson, Joan E; Edwards, Jerri D; Ackerman, Michelle L; Ball, Karlene

2012-09-01

Many U.S. states rely on older adults to self-regulate their driving and determine when driving is no longer a safe option. However, the relationship of older adults' self-rated driving in terms of actual driving competency outcomes is unclear. The current study investigates self-rated driving in terms of (1) systematic differences between older adults with high (good/excellent) versus low (poor/fair/average) self-ratings, and (2) the predictive nature of self-rated driving to adverse driving outcomes in older adults (n=350; mean age 73.9, SD=5.25, range 65-91). Adverse driving outcomes included self-reported incidences of (1) being pulled over by the police, (2) receiving a citation, (3) receiving a recommendation to cease or limit driving, (4) crashes, and (5) state-reported crashes. Results found that older drivers with low self-ratings reported more medical conditions, less driving frequency, and had been given more suggestions to stop/limit their driving; there were no other significant differences between low and high self-raters. Logistic regression revealed older drivers were more likely to have a state-reported crash and receive a suggestion to stop or limit driving. Men were more likely to report all adverse driving outcomes except for receiving a suggestion to stop or limit driving. Regarding self-rated driving, older adults with high ratings were 66% less likely (OR=0.34, 95% CI=0.14-0.85) to have received suggestions to limit or stop driving after accounting for demographics, health and driving frequency. Self-ratings were not predictive of other driving outcomes (being pulled over by the police, receiving a citation, self-reported crashes, or state-reported crashes, ps>0.05). Most older drivers (85.14%) rated themselves as either good or excellent drivers regardless of their actual previous citation or crash rates. Self-rated driving is likely not related to actual driving proficiency as indicated by previous crash involvement in older adults. Suggestions from other individuals to limit or cease driving may be more influential on self-ratings. Copyright © 2012 Elsevier Ltd. All rights reserved.

Self-rated Driving and Driving Safety in Older Adults

PubMed Central

Ross, Lesley A.; Dodson, Joan; Edwards, Jerri D.; Ackerman, Michelle L.; Ball, Karlene

2012-01-01

Many U.S. states rely on older adults to self-regulate their driving and determine when driving is no longer a safe option. However, the relationship of older adults’ self-rated driving in terms of actual driving competency outcomes is unclear. The current study investigates self-rated driving in terms of (1) systematic differences between older adults with high (good/excellent) versus low (poor/fair/average) self-ratings, and (2) the predictive nature of self-rated driving to adverse driving outcomes in older drivers (n=350; mean age 73.9, SD=5.25, range 65–91). Adverse driving outcomes included self-reported incidences of (1) being pulled over by the police, (2) receiving a citation, (3) receiving a recommendation to cease or limit driving, (4) crashes, and (5) state-reported crashes. Results found that older drivers with low self-ratings reported more medical conditions, less driving frequency, and had been given more suggestions to stop/limit their driving; there were no other significant differences between low and high self-raters. Logistic regression revealed older drivers were more likely to have a state-reported crash and receive a suggestion to stop or limit driving. Men were more likely to report all adverse driving outcomes except for receiving a suggestion to stop or limit driving. Regarding self-rated driving, older adults with high ratings were 66% less likely (OR=0.34, 95% CI=0.14–0.85) to have received suggestions to limit or stop driving after accounting for demographics, health and driving frequency. Self-ratings were not predictive of other driving outcomes (being pulled over by the police, receiving a citation, self-reported crashes, or state-reported crashes, ps>.05). Most older drivers (85.14%) rated themselves as either good or excellent drivers regardless of their actual previous citation or crash rates. Self-rated driving is likely not related to actual driving proficiency as indicated by previous crash involvement in older adults. Suggestions from other individuals to limit or cease driving may be more influential on self-ratings. PMID:22664719

Survey of heating and current drive for K-DEMO

NASA Astrophysics Data System (ADS)

Mikkelsen, D. R.; Kessel, C. E.; Poli, F. M.; Bertelli, N.; Kim, K.

2018-03-01

We present calculations of heating and current drive by neutral injection and by electromagnetic waves in the ion cyclotron, helicon, lower hybrid, and electron cyclotron frequency ranges for the steady state burn conditions in a K-DEMO configuration with I_p=12.3 MA, a  =  2.1 m, R_o=6.8 m, B_o=7.4 T, \

Drive Beam Shaping and Witness Bunch Generation for the Plasma Wakefield Accelerator

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

England, R. J.; Frederico, J.; Hogan, M. J.

2010-11-04

High transformer ratio operation of the plasma wake field accelerator requires a tailored drive beam current profile followed by a short witness bunch. We discuss techniques for generating the requisite dual bunches and for obtaining the desired drive beam profile, with emphasis on the FACET experiment at SLAC National Accelerator Laboratory.

Interpretation of steam drive pilots in the Belridge Diatomite

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

Johnston, R.M.; Shahin, G.T.

1995-12-31

The South Belridge Diatomite Field contains more than 2.5 billion barrels of oil-in-place. Current primary and waterflood development are estimated to recover only a small fraction of this oil. Despite its low permeability, the diatomite may be a good candidate for the steam drive process, due to its thick oil column (1,000 ft), high porosity (50% to 65%), and high oil saturation (up to 70%). With these attributes, thermal expansion and decreased viscosity of reservoir fluids accelerate oil production, without significant heat loss to cap and base rock. Steam drive pilot operations have been conducted at South Belridge since 1986.more » This paper discusses the pilot projects and the 15-acre steam drive full-scale project currently being installed.« less

Baseline tests of the Kordesh hybrid passenger vehicle

NASA Technical Reports Server (NTRS)

Soltis, R. F.; Bozek, J. M.; Denington, R. J.; Dustin, M. O.

1978-01-01

Performance test results are presented for a four-passenger Austin A40 sedan that was converted to a heat-engine-alternator-and battery-powered hybrid. It is propelled by a conventional, gasoline-fueled, heat-engine-driven alternator and a traction pack powering a series-wound, 10 hp direct-current electric drive motor. The 16 hp gasoline engine drives the 7 kilowatt alternator, which provides electrical power to the drive motor or to the 96 volt traction battery through a rectifier. The propulsion battery consists of eight 12 volt batteries connected in series. The electric motor is coupled to a four-speed standard transmission, which drives the rear wheels. Power to the motor is controlled by a three-step foot throttle, which actuates relays that control armature current and field excitation. Conventional hydraulic brakes are used.

Evaluating the effectiveness of a post-license education program for young novice drivers in Belgium.

PubMed

Brijs, Kris; Cuenen, Ariane; Brijs, Tom; Ruiter, Robert A C; Wets, Geert

2014-05-01

The disproportionately large number of traffic accidents of young novice drivers highlights the need for an effective driver education program. The Goals for Driving Education (GDE) matrix shows that driver education must target both lower and higher levels of driver competences. Research has indicated that current education programs do not emphasize enough the higher levels, for example awareness and insight. This has raised the importance of insight programs. On the Road (OtR), a Flemish post-license driver education program, is such an insight program that aims to target these higher levels. The program focus is on risky driving behavior like speeding and drink driving. In addition, the program addresses risk detection and risk-related knowledge. The goal of the study was to do an effect evaluation of this insight program at immediate post-test and 2 months follow-up. In addition, the study aimed to generalize the results of this program to comparable programs in order to make usable policy recommendations. A questionnaire based on the Theory of Planned Behavior (TPB) was used in order to measure participants' safety consciousness of speeding and drink driving. Moreover, we focused on risk detection and risk-related knowledge. Participants (N=366) were randomly assigned to a baseline-follow-up group or a post-test-follow-up group. Regarding speeding and driving, we found OtR to have little effect on the TPB variables. Regarding risk detection, we found no significant effect, even though participants clearly needed substantial improvement when stepping into the program. Regarding risk-related knowledge, the program did result in a significant improvement at post-test and follow-up. It is concluded that the current program format is a good starting point, but that it requires further attention to enhance high level driving skills. Program developers are encouraged to work in a more evidence-based manner when they select target variables and methods to influence these variables. Copyright © 2014 Elsevier Ltd. All rights reserved.

Parent attitudes toward integrating parent involvement into teenage driver education courses.

PubMed

Hartos, Jessica; Huff, David C

2008-01-01

The widespread adoption of graduated driver licensing (GDL) policies has effectively reduced crash risk for young drivers; however, parents must support, reinforce, and enforce GDL for it to be effective, and research indicates that parents need better information and instruction for adhering to GDL requirements, conducting supervised practice driving, and restricting independent teenage driving. Because teenagers in most states must take driver education to enter the licensing process prior to age 18, integrating parent involvement into driver education may be an effective way to inform and instruct parents on a large scale about teen driver safety. This study assessed parent attitudes (overall and by rural status, minority status, and income level) toward integrating parent involvement into teenage driver education classes. In this study, 321 parents of teenagers enrolled in driver education classes across the state of Montana completed surveys about current involvement in driver education and attitudes toward required involvement. The results indicated that parents were not very involved currently in their teenagers' driver education classes, but 76% reported that parents should be required to be involved. If involvement were required, parents would prefer having written materials sent home, access to information over the Internet, or discussions in person with the instructor; far fewer would prefer to attend classes or behind-the-wheel driving instruction. There were few differences in parent attitudes by rural or minority status but many by income level. Compared to higher income parents, lower income parents were more likely to endorse required parent involvement in teenage driver education classes and to want parent information from driver education about many teen driving issues. That the majority of parents are open to required involvement in their teenagers' driver education classes is promising because doing so could better prepare parents to understand and adhere to GDL policies, supervise teenagers' practice driving, and manage teen independent driving, all of which could further increase teen driver safety.

Current profile redistribution driven by neutral beam injection in a reversed-field pinch

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

Parke, E.; Department of Physics, University of Wisconsin-Madison 1150 University Ave., Madison, Wisconsin 53706; Anderson, J. K.

2016-05-15

Neutral beam injection in reversed-field pinch (RFP) plasmas on the Madison Symmetric Torus [Dexter et al., Fusion Sci. Technol. 19, 131 (1991)] drives current redistribution with increased on-axis current density but negligible net current drive. Internal fluctuations correlated with tearing modes are observed on multiple diagnostics; the behavior of tearing mode correlated structures is consistent with flattening of the safety factor profile. The first application of a parametrized model for island flattening to temperature fluctuations in an RFP allows inferrence of rational surface locations for multiple tearing modes. The m = 1, n = 6 mode is observed to shift inward by 1.1 ± 0.6 cm withmore » neutral beam injection. Tearing mode rational surface measurements provide a strong constraint for equilibrium reconstruction, with an estimated reduction of q{sub 0} by 5% and an increase in on-axis current density of 8% ± 5%. The inferred on-axis current drive is consistent with estimates of fast ion density using TRANSP [Goldston et al., J. Comput. Phys. 43, 61 (1981)].« less

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.

Low-jitter high-power thyristor array pulse driver and generator

DOEpatents

Hanks, Roy L.

2002-01-01

A method and apparatus for generating low-jitter, high-voltage and high-current pulses for driving low impedance loads such as detonator fuses uses a MOSFET driver which, when triggered, discharges a high-voltage pre-charged capacitor into the primary of a toroidal current-multiplying transformer with multiple isolated secondary windings. The secondary outputs are suitable for driving an array of thyristors that discharge a precharged high-voltage capacitor and thus generating the required high-voltage and high-current pulse.

Planning for a Nondriving Future: Behaviors and Beliefs Among Middle-Aged and Older Drivers.

PubMed

Harmon, Annie C; Babulal, Ganesh; Vivoda, Jonathon M; Zikmund-Fisher, Brian J; Carr, David B

2018-01-01

Despite the reality of older adults living many years after driving cessation, few prepare for the eventuality; empirically, planning for a nondriving future has not been directly quantified or explored. The following study quantifies 1) the extent of current drivers' planning, 2) specific planning behaviors, 3) beliefs about benefits of planning, 4) drivers' intention to plan more for future transportation needs, and 5) group differences associated with planning. In a predominantly female, black, urban sample of current drivers ages 53-92, fewer than half (42.1%) had planned at all for a nondriving future, with correspondingly low levels of planning behaviors reported. However, over 80% believed planning would help them meet their needs post-cessation and transition emotionally to being a nondriver. Most (85%) intended to plan more in the future as well, indicating further potential openness to the topic. Drivers who planned were older, drove less frequently, limited their driving to nearby places, reported less difficulty believing they would become a nondriver, and expected to continue driving three years less than non-planners. These findings suggest that drivers' perceived nearness to driving cessation impacts planning for future transportation needs, and existing perceived benefits of planning may provide leverage to motivate action.

Exploring the Driving Factors of Construction Industrialization Development in China.

PubMed

Xiahou, Xiaer; Yuan, Jingfeng; Liu, Yan; Tang, Yuchun; Li, Qiming

2018-03-03

Construction industrialization (CI) has been adopted worldwide because of its potential benefits. However, current research shows the incentives for adopting CI may differ in different regions. While the promotion of CI in China is still at the initial stage, a systematical analysis of the driving factors would help decision makers get a comprehensive understanding of CI development and select proper strategies to promote CI. This research combines qualitative and quantitative methods to explore the construction industrialization driving factors (CIDFs) in China. The grounded theory method (GTM) was employed to explore CI concepts among 182 CI-related articles published in 10 top-tier journals from 2000 to 2017. A total of 15 CIDFs were identified, including one suggested by professionals during a pre-test questionnaire survey. The analysis showed that the development of CI in China is pushed by macrodevelopment and pulled by the government and is also a self-driven process. The major driving factors for CI adoption in China are the transformation and upgrade of the conventional construction industry and the solution of development dilemmas. Our study also suggests that pilot programs are, currently, the most effective method to promote CI in China and to accumulate experience so to gain recognition by the society. This research is also of value for CI promotion in other developing countries.

Fabrication of amorphous InGaZnO thin-film transistor-driven flexible thermal and pressure sensors

NASA Astrophysics Data System (ADS)

Park, Ick-Joon; Jeong, Chan-Yong; Cho, In-Tak; Lee, Jong-Ho; Cho, Eou-Sik; Kwon, Sang Jik; Kim, Bosul; Cheong, Woo-Seok; Song, Sang-Hun; Kwon, Hyuck-In

2012-10-01

In this work, we present the results concerning the use of amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistor (TFT) as a driving transistor of the flexible thermal and pressure sensors which are applicable to artificial skin systems. Although the a-IGZO TFT has been attracting much attention as a driving transistor of the next-generation flat panel displays, no study has been performed about the application of this new device to the driving transistor of the flexible sensors yet. The proposed thermal sensor pixel is composed of the series-connected a-IGZO TFT and ZnO-based thermistor fabricated on a polished metal foil, and the ZnO-based thermistor is replaced by the pressure sensitive rubber in the pressure sensor pixel. In both sensor pixels, the a-IGZO TFT acts as the driving transistor and the temperature/pressure-dependent resistance of the ZnO-based thermistor/pressure-sensitive rubber mainly determines the magnitude of the output currents. The fabricated a-IGZO TFT-driven flexible thermal sensor shows around a seven times increase in the output current as the temperature increases from 20 °C to 100 °C, and the a-IGZO TFT-driven flexible pressure sensors also exhibit high sensitivity under various pressure environments.

Exploring the Driving Factors of Construction Industrialization Development in China

PubMed Central

Xiahou, Xiaer; Yuan, Jingfeng; Tang, Yuchun; Li, Qiming

2018-01-01

Construction industrialization (CI) has been adopted worldwide because of its potential benefits. However, current research shows the incentives for adopting CI may differ in different regions. While the promotion of CI in China is still at the initial stage, a systematical analysis of the driving factors would help decision makers get a comprehensive understanding of CI development and select proper strategies to promote CI. This research combines qualitative and quantitative methods to explore the construction industrialization driving factors (CIDFs) in China. The grounded theory method (GTM) was employed to explore CI concepts among 182 CI-related articles published in 10 top-tier journals from 2000 to 2017. A total of 15 CIDFs were identified, including one suggested by professionals during a pre-test questionnaire survey. The analysis showed that the development of CI in China is pushed by macrodevelopment and pulled by the government and is also a self-driven process. The major driving factors for CI adoption in China are the transformation and upgrade of the conventional construction industry and the solution of development dilemmas. Our study also suggests that pilot programs are, currently, the most effective method to promote CI in China and to accumulate experience so to gain recognition by the society. This research is also of value for CI promotion in other developing countries. PMID:29510507

The methodological quality of three foundational law enforcement Drug Influence Evaluation validation studies.

PubMed

Kane, Greg

2013-11-04

A Drug Influence Evaluation (DIE) is a formal assessment of an impaired driving suspect, performed by a trained law enforcement officer who uses circumstantial facts, questioning, searching, and a physical exam to form an unstandardized opinion as to whether a suspect's driving was impaired by drugs. This paper first identifies the scientific studies commonly cited in American criminal trials as evidence of DIE accuracy, and second, uses the QUADAS tool to investigate whether the methodologies used by these studies allow them to correctly quantify the diagnostic accuracy of the DIEs currently administered by US law enforcement. Three studies were selected for analysis. For each study, the QUADAS tool identified biases that distorted reported accuracies. The studies were subject to spectrum bias, selection bias, misclassification bias, verification bias, differential verification bias, incorporation bias, and review bias. The studies quantified DIE performance with prevalence-dependent accuracy statistics that are internally but not externally valid. The accuracies reported by these studies do not quantify the accuracy of the DIE process now used by US law enforcement. These studies do not validate current DIE practice.

An Opportunity for Convergence? Understanding the Prevalence and Risk of Distracted Driving Through the Use of Crash Databases, Crash Investigations, and Other Approaches

PubMed Central

Angell, Linda S.

2014-01-01

A variety of methodologies for understanding the prevalence of distracted driving, its risk, and other aspects of driver secondary activity, have been used in the last 15 years. Although the current trend is toward naturalistic driving studies, each methodology contributes certain elements to a better understanding that could emerge from a convergence of these efforts. However, if differing methods are to contribute to a common and robust understanding of driver distraction, it is critical to understand the strengths and limitations of each method. This paper reviews several of the non-naturalistic methods. It suggests that “convergence science” – a more concerted and rigorous effort to bring different approaches together into an integrative whole – may offer benefits for identification and definition of issues and countermeasure development to improve driving safety. PMID:24776226

Is a hands-free phone safer than a handheld phone?

PubMed

Ishigami, Yoko; Klein, Raymond M

2009-01-01

Although it is becoming more and more accepted that driving while talking on a cell phone can be hazardous, most jurisdictions are making handheld phone use illegal while allowing hands-free phone use. The scientific literature exploring the effects of these two types of cell phone use on driving and driving-related performance is reviewed here. Our review shows that talking on the phone, regardless of phone type, has negative impacts on performance especially in detecting and identifying events. Performance while using a hands-free phone was rarely found to be better than when using a handheld phone. Some studies found that drivers compensate for the deleterious effects of cell phone use when using a handheld phone but neglect to do so when using a hands-free phone. Current research does not support the decision to allow hands-free phone use while driving.

Pile Driving

NASA Technical Reports Server (NTRS)

1987-01-01

Machine-oriented structural engineering firm TERA, Inc. is engaged in a project to evaluate the reliability of offshore pile driving prediction methods to eventually predict the best pile driving technique for each new offshore oil platform. Phase I Pile driving records of 48 offshore platforms including such information as blow counts, soil composition and pertinent construction details were digitized. In Phase II, pile driving records were statistically compared with current methods of prediction. Result was development of modular software, the CRIPS80 Software Design Analyzer System, that companies can use to evaluate other prediction procedures or other data bases.

Current inversion in the Lévy ratchet.

PubMed

Dybiec, Bartłomiej

2008-12-01

We study the motion of an overdamped test particle in a static periodic potential lacking spatial symmetry under the influence of periodically modulated alpha -stable (Lévy) type noise. Due to the nonthermal character of the driving noise, the particle exhibits a motion with a preferred direction. The additional periodic modulation of the noise asymmetry changes the behavior of the static "Lévy ratchet." For the fast rate of the noise asymmetry modulation, the Lévy ratchet behaves like the one driven by the symmetric alpha -stable noise. When the modulation period is larger, the nontrivial effects of the noise asymmetry on the behavior of the Lévy ratchet are visible. In particular, the current inversion is observed in the system at hand. The properties of the Lévy ratchet are studied by use of the robust measures of directionality, which are defined regardless of the type of the stochastic driving.

Do Magnetic Fields Drive High-Energy Explosive Transients?

NASA Astrophysics Data System (ADS)

Mundell, Carole

2017-10-01

I will review the current state-of-the-art in real-time, rapid response optical imaging and polarimetric followup of transient sources such as Gamma Ray Bursts. I will interpret current results within the context of the external shock model and present predictions for future mm- and cm-wave radio observatories. Recent observational results from new radio pilot studies will also be presented.

Greater cerebellar gray matter volume in car drivers: an exploratory voxel-based morphometry study

PubMed Central

Sakai, Hiroyuki; Ando, Takafumi; Sadato, Norihiro; Uchiyama, Yuji

2017-01-01

Previous functional neuroimaging studies have identified multiple brain areas associated with distinct aspects of car driving in simulated traffic environments. Few studies, however, have examined brain morphology associated with everyday car-driving experience in real traffic. Thus, the aim of the current study was to identify gray matter volume differences between drivers and non-drivers. We collected T1-weighted structural brain images from 73 healthy young adults (36 drivers and 37 non-drivers). We performed a whole-brain voxel-based morphometry analysis to examine between-group differences in regional gray matter volume. Compared with non-drivers, drivers showed significantly greater gray matter volume in the left cerebellar hemisphere, which has been associated with cognitive rather than motor functioning. In contrast, we found no brain areas with significantly greater gray matter volume in non-drivers compared with drivers. Our findings indicate that experience with everyday car driving in real traffic is associated with greater gray matter volume in the left cerebellar hemisphere. This brain area may be involved in abilities that are critical for driving a car, but are not commonly or frequently used during other daily activities. PMID:28417971

Greater cerebellar gray matter volume in car drivers: an exploratory voxel-based morphometry study.

PubMed

Sakai, Hiroyuki; Ando, Takafumi; Sadato, Norihiro; Uchiyama, Yuji

2017-04-18

Previous functional neuroimaging studies have identified multiple brain areas associated with distinct aspects of car driving in simulated traffic environments. Few studies, however, have examined brain morphology associated with everyday car-driving experience in real traffic. Thus, the aim of the current study was to identify gray matter volume differences between drivers and non-drivers. We collected T1-weighted structural brain images from 73 healthy young adults (36 drivers and 37 non-drivers). We performed a whole-brain voxel-based morphometry analysis to examine between-group differences in regional gray matter volume. Compared with non-drivers, drivers showed significantly greater gray matter volume in the left cerebellar hemisphere, which has been associated with cognitive rather than motor functioning. In contrast, we found no brain areas with significantly greater gray matter volume in non-drivers compared with drivers. Our findings indicate that experience with everyday car driving in real traffic is associated with greater gray matter volume in the left cerebellar hemisphere. This brain area may be involved in abilities that are critical for driving a car, but are not commonly or frequently used during other daily activities.

From current-driven to neoclassically driven tearing modes.

PubMed

Reimerdes, H; Sauter, O; Goodman, T; Pochelon, A

2002-03-11

In the TCV tokamak, the m/n = 2/1 island is observed in low-density discharges with central electron-cyclotron current drive. The evolution of its width has two distinct growth phases, one of which can be linked to a "conventional" tearing mode driven unstable by the current profile and the other to a neoclassical tearing mode driven by a perturbation of the bootstrap current. The TCV results provide the first clear observation of such a destabilization mechanism and reconcile the theory of conventional and neoclassical tearing modes, which differ only in the dominant driving term.

Vehicle Test Procedure Driving Schedules

DOT National Transportation Integrated Search

1977-03-01

This report discusses the salient characteristics of driving schedules which are currently being used to determine automotive fuel economy, exhaust emissions, and component characteristics. The analyses discussed and the results reported highlight th...

Improving the driver-automation interaction: an approach using automation uncertainty.

PubMed

Beller, Johannes; Heesen, Matthias; Vollrath, Mark

2013-12-01

The aim of this study was to evaluate whether communicating automation uncertainty improves the driver-automation interaction. A false system understanding of infallibility may provoke automation misuse and can lead to severe consequences in case of automation failure. The presentation of automation uncertainty may prevent this false system understanding and, as was shown by previous studies, may have numerous benefits. Few studies, however, have clearly shown the potential of communicating uncertainty information in driving. The current study fills this gap. We conducted a driving simulator experiment, varying the presented uncertainty information between participants (no uncertainty information vs. uncertainty information) and the automation reliability (high vs.low) within participants. Participants interacted with a highly automated driving system while engaging in secondary tasks and were required to cooperate with the automation to drive safely. Quantile regressions and multilevel modeling showed that the presentation of uncertainty information increases the time to collision in the case of automation failure. Furthermore, the data indicated improved situation awareness and better knowledge of fallibility for the experimental group. Consequently, the automation with the uncertainty symbol received higher trust ratings and increased acceptance. The presentation of automation uncertaintythrough a symbol improves overall driver-automation cooperation. Most automated systems in driving could benefit from displaying reliability information. This display might improve the acceptance of fallible systems and further enhances driver-automation cooperation.

Prior Familiarization With Takeover Requests Affects Drivers' Takeover Performance and Automation Trust.

PubMed

Hergeth, Sebastian; Lorenz, Lutz; Krems, Josef F

2017-05-01

The objective for this study was to investigate the effects of prior familiarization with takeover requests (TORs) during conditional automated driving on drivers' initial takeover performance and automation trust. System-initiated TORs are one of the biggest concerns for conditional automated driving and have been studied extensively in the past. Most, but not all, of these studies have included training sessions to familiarize participants with TORs. This makes them hard to compare and might obscure first-failure-like effects on takeover performance and automation trust formation. A driving simulator study compared drivers' takeover performance in two takeover situations across four prior familiarization groups (no familiarization, description, experience, description and experience) and automation trust before and after experiencing the system. As hypothesized, prior familiarization with TORs had a more positive effect on takeover performance in the first than in a subsequent takeover situation. In all groups, automation trust increased after participants experienced the system. Participants who were given no prior familiarization with TORs reported highest automation trust both before and after experiencing the system. The current results extend earlier findings suggesting that prior familiarization with TORs during conditional automated driving will be most relevant for takeover performance in the first takeover situation and that it lowers drivers' automation trust. Potential applications of this research include different approaches to familiarize users with automated driving systems, better integration of earlier findings, and sophistication of experimental designs.

In the eye of the beholder: A simulator study of the impact of Google Glass on driving performance.

PubMed

Young, Kristie L; Stephens, Amanda N; Stephan, Karen L; Stuart, Geoffrey W

2016-01-01

This study examined whether, and to what extent, driving is affected by reading text on Google Glass. Reading text requires a high level of visual resources and can interfere with safe driving. However, it is currently unclear if the impact of reading text on a head-mounted display, such as Google Glass (Glass), will differ from that found with more traditional head-down electronic devices, such as a dash-mounted smartphone. A total of 20 drivers (22-48 years) completed the Lane Change Test while driving undistracted and while reading text on Glass and on a smartphone. Measures of lateral vehicle control and event detection were examined along with subjective workload and secondary task performance. Results revealed that drivers' lane keeping ability was significantly impaired by reading text on both Glass and the smartphone. When using Glass, drivers also failed to detect a greater number of lane change signs compared to when using the phone or driving undistracted. In terms of subjective workload, drivers rated reading on Glass as subjectively easier than on the smartphone, which may possibly encourage greater use of this device while driving. Overall, the results suggest that, despite Glass allowing drivers to better maintain their visual attention on the forward scene, drivers are still not able to effectively divide their cognitive attention across the Glass display and the road environment, resulting in impaired driving performance. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effects of electron cyclotron current drive on the evolution of double tearing mode

NASA Astrophysics Data System (ADS)

Sun, Guanglan; Dong, Chunying; Duan, Longfang

2015-09-01

The effects of electron cyclotron current drive (ECCD) on the double tearing mode (DTM) in slab geometry are investigated by using two-dimensional compressible magnetohydrodynamics equations. It is found that, mainly, the double tearing mode is suppressed by the emergence of the secondary island, due to the deposition of driven current on the X-point of magnetic island at one rational surface, which forms a new non-complete symmetric magnetic topology structure (defined as a non-complete symmetric structure, NSS). The effects of driven current with different parameters (magnitude, initial time of deposition, duration time, and location of deposition) on the evolution of DTM are analyzed elaborately. The optimal magnitude or optimal deposition duration of driven current is the one which makes the duration of NSS the longest, which depends on the mutual effect between ECCD and the background plasma. Moreover, driven current introduced at the early Sweet-Parker phase has the best suppression effect; and the optimal moment also exists, depending on the duration of the NSS. Finally, the effects varied by the driven current disposition location are studied. It is verified that the favorable location of driven current is the X-point which is completely different from the result of single tearing mode.

Simulations towards the achievement of non-inductive current ramp-up and sustainment in the National Spherical Torus Experiment Upgrade

DOE PAGES

Poli, F. M.; Andre, R. G.; Bertelli, N.; ...

2015-10-30

One of the goals of the National Spherical Torus Experiment Upgrade (NSTX-U) (Menard et al 2012 Nucl. Fusion 52 083015) is the demonstration of fully non-inductive start-up, current ramp-up and sustainment. This work discusses predictive simulations where the available heating and current drive systems are combined to maximize the non-inductive current and minimize the solenoidal contribution. Radio-frequency waves at harmonics higher than the ion cyclotron resonance (high-harmonic fast waves (HHFW)) and neutral beam injection are used to ramp the plasma current non-inductively starting from an initial Ohmic plasma. An interesting synergy is observed in the simulations between the HHFW andmore » electron cyclotron (EC) wave heating. Furthermore, time-dependent simulations indicate that, depending on the phasing of the HHFW antenna, EC wave heating can significantly increase the effectiveness of the radio-frequency power, by heating the electrons and increasing the current drive efficiency, thus relaxing the requirements on the level of HHFW power that needs to be absorbed in the core plasma to drive the same amount of fast-wave current.« less

The magnetospheric currents - An introduction

NASA Technical Reports Server (NTRS)

Akasofu, S.-I.

1984-01-01

It is pointed out that the scientific discipline concerned with magnetospheric currents has grown out from geomagnetism and, in particular, from geomagnetic storm studies. The International Geophysical Year (IGY) introduced a new area for this discipline by making 'man-made satellites' available for the exploration of space around the earth. In this investigation, a brief description is provided of the magnetospheric currents in terms of eight component current systems. Attention is given to the Sq current, the Chapman-Ferraro current, the ring current (the symmetric component), the current systems driven by the solar wind-magnetosphere dynamo (SMD), the cross-tail current system, the average ionospheric current pattern, an example of an instantaneous current pattern, field-aligned currents, and driving mechanisms and models.

Cellular phone use while driving at night.

PubMed

Vivoda, Jonathon M; Eby, David W; St Louis, Renée M; Kostyniuk, Lidia P

2008-03-01

Use of a cellular phone has been shown to negatively affect one's attention to the driving task, leading to an increase in crash risk. At any given daylight hour, about 6% of US drivers are actively talking on a hand-held cell phone. However, previous surveys have focused only on cell phone use during the day. Driving at night has been shown to be a riskier activity than driving during the day. The purpose of the current study was to assess the rate of hand-held cellular phone use while driving at night, using specialized night vision equipment. In 2006, two statewide direct observation survey waves of nighttime cellular phone use were conducted in Indiana utilizing specialized night vision equipment. Combined results of driver hand-held cellular phone use from both waves are presented in this manuscript. The rates of nighttime cell phone use were similar to results found in previous daytime studies. The overall rate of nighttime hand-held cellular phone use was 5.8 +/- 0.6%. Cellular phone use was highest for females and for younger drivers. In fact, the highest rate observed during the study (of 11.9%) was for 16-to 29-year-old females. The high level of cellular phone use found within the young age group, coupled with the increased crash risk associated with cellular phone use, nighttime driving, and for young drivers in general, suggests that this issue may become an important transportation-related concern.

Non-inductive current drive and transport in high βN plasmas in JET

NASA Astrophysics Data System (ADS)

Voitsekhovitch, I.; Alper, B.; Brix, M.; Budny, R. V.; Buratti, P.; Challis, C. D.; Ferron, J.; Giroud, C.; Joffrin, E.; Laborde, L.; Luce, T. C.; McCune, D.; Menard, J.; Murakami, M.; Park, J. M.; JET-EFDA contributors

2009-05-01

A route to stationary MHD stable operation at high βN has been explored at the Joint European Torus (JET) by optimizing the current ramp-up, heating start time and the waveform of neutral beam injection (NBI) power. In these scenarios the current ramp-up has been accompanied by plasma pre-heat (or the NBI has been started before the current flat-top) and NBI power up to 22 MW has been applied during the current flat-top. In the discharges considered transient total βN ≈ 3.3 and stationary (during high power phase) βN ≈ 3 have been achieved by applying the feedback control of βN with the NBI power in configurations with monotonic or flat core safety factor profile and without an internal transport barrier (ITB). The transport and current drive in this scenario is analysed here by using the TRANSP and ASTRA codes. The interpretative analysis performed with TRANSP shows that 50-70% of current is driven non-inductively; half of this current is due to the bootstrap current which has a broad profile since an ITB was deliberately avoided. The GLF23 transport model predicts the temperature profiles within a ±22% discrepancy with the measurements over the explored parameter space. Predictive simulations with this model show that the E × B rotational shear plays an important role for thermal ion transport in this scenario, producing up to a 40% increase of the ion temperature. By applying transport and current drive models validated in self-consistent simulations of given reference scenarios in a wider parameter space, the requirements for fully non-inductive stationary operation at JET are estimated. It is shown that the strong stiffness of the temperature profiles predicted by the GLF23 model restricts the bootstrap current at larger heating power. In this situation full non-inductive operation without an ITB can be rather expensive strongly relying on the external non-inductive current drive sources.

Survey of heating and current drive for K-DEMO

DOE PAGES

Mikkelsen, D. R.; Kessel, C. E.; Poli, F. M.; ...

2018-01-22

Here, we present calculations of heating and current drive by neutral injection and by electromagnetic waves in the ion cyclotron, helicon, lower hybrid, and electron cyclotron frequency ranges for the steady state burn conditions in a K-DEMO configuration withmore » $$I_{\\rm p}=12.3$$ MA, a = 2.1 m, $$R_{\\rm o}=6.8$$ m, $$B_{\\rm o}=7.4$$ T, $$ \

Survey of heating and current drive for K-DEMO

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

Mikkelsen, D. R.; Kessel, C. E.; Poli, F. M.

Here, we present calculations of heating and current drive by neutral injection and by electromagnetic waves in the ion cyclotron, helicon, lower hybrid, and electron cyclotron frequency ranges for the steady state burn conditions in a K-DEMO configuration withmore » $$I_{\\rm p}=12.3$$ MA, a = 2.1 m, $$R_{\\rm o}=6.8$$ m, $$B_{\\rm o}=7.4$$ T, $$ \

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.

Dangers of Texting While Driving

MedlinePlus

... it be shared with students and parents. State laws Currently there is no national ban on texting ... driving, but a number of states have passed laws banning texting or wireless phones or requiring hands- ...

Design and simulation of control algorithms for stored energy and plasma current in non-inductive scenarios on NSTX-U

NASA Astrophysics Data System (ADS)

Boyer, Mark; Andre, Robert; Gates, David; Gerhardt, Stefan; Menard, Jonathan; Poli, Francesca

2015-11-01

One of the major goals of NSTX-U is to demonstrate non-inductive operation. To facilitate this and other program goals, the center stack has been upgraded and a second neutral beam line has been added with three sources aimed more tangentially to provide higher current drive efficiency and the ability to shape the current drive profile. While non-inductive start-up and ramp-up scenarios are being developed, initial non-inductive studies will likely rely on clamping the Ohmic coil current after the plasma current has been established inductively. In this work the ability to maintain control of stored energy and plasma current once the Ohmic coil has been clamped is explored. The six neutral beam sources and the mid-plane outer gap of the plasma are considered as actuators. System identification is done using TRANSP simulations in which the actuators are modulated around a reference shot. The resulting reduced model is used to design an optimal control law with anti-windup and a recently developed framework for closed loop simulations in TRANSP is used to test the control. Limitations due to actuator saturation are assessed and robustness to beam modulation, changes in the plasma density and confinement, and changes in density and temperature profile shapes are studied. Supported by US DOE contract DE-AC02-09CH11466.

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

Drugs and driving : a research review

DOT National Transportation Integrated Search

1977-01-01

The report presents the results of a study of the relationship between drugs (other than alcohol alone) and highway safety. The state of the art of current research is examined. Conclusions and recommendations for future action and research are made....

Detecting and Quantifying Mind Wandering during Simulated Driving

DOT National Transportation Integrated Search

2017-08-08

Mind wandering is a pervasive threat to transportation safety, potentially accounting for a substantial number of crashes and fatalities. In the current study, mind wandering was induced through completion of the same task for 5 days, consisting of a...

Numerical magnetohydrodynamic simulations of expanding flux ropes: Influence of boundary driving

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

Tacke, Thomas; Dreher, Jürgen; Sydora, Richard D.

2013-07-15

The expansion dynamics of a magnetized, current-carrying plasma arch is studied by means of time-dependent ideal MHD simulations. Initial conditions model the setup used in recent laboratory experiments that in turn simulate coronal loops [J. Tenfelde et al., Phys. Plasmas 19, 072513 (2012); E. V. Stenson and P. M. Bellan, Plasma Phys. Controlled Fusion 54, 124017 (2012)]. Boundary conditions of the electric field at the “lower” boundary, intersected by the arch, are chosen such that poloidal magnetic flux is injected into the domain, either localized at the arch footpoints themselves or halfway between them. These conditions are motivated by themore » tangential electric field expected to exist in the laboratory experiments due to the external circuit that drives the plasma current. The boundary driving is found to systematically enhance the expansion velocity of the plasma arch. While perturbations at the arch footpoints also deform its legs and create characteristic elongated segments, a perturbation between the footpoints tends to push the entire structure upwards, retaining an ellipsoidal shape.« less

Driving Method for Compensating Reliability Problem of Hydrogenated Amorphous Silicon Thin Film Transistors and Image Sticking Phenomenon in Active Matrix Organic Light-Emitting Diode Displays

NASA Astrophysics Data System (ADS)

Shin, Min-Seok; Jo, Yun-Rae; Kwon, Oh-Kyong

2011-03-01

In this paper, we propose a driving method for compensating the electrical instability of hydrogenated amorphous silicon (a-Si:H) thin film transistors (TFTs) and the luminance degradation of organic light-emitting diode (OLED) devices for large active matrix OLED (AMOLED) displays. The proposed driving method senses the electrical characteristics of a-Si:H TFTs and OLEDs using current integrators and compensates them by an external compensation method. Threshold voltage shift is controlled a using negative bias voltage. After applying the proposed driving method, the measured error of the maximum emission current ranges from -1.23 to +1.59 least significant bit (LSB) of a 10-bit gray scale under the threshold voltage shift ranging from -0.16 to 0.17 V.

Why don't northern American solutions to drinking and driving work in southern America?

PubMed

Pechansky, Flavio; Chandran, Aruna

2012-07-01

While individual studies from several South American countries have shown driving while intoxicated to be a problem, there are no objective systematically collected alcohol-associated driving data obtained in most South American countries. This limits their ability to implement and enforce targeted prevention strategies, evaluate whether proven prevention efforts from North America (particularly the United States and Canada) can be transferred to the South, and to sustain momentum for the improvement of road safety by demonstrating that previously implemented legal and policy changes are effective. The aim of this paper is to discuss the abysmal differences that exist between northern and southern American countries regarding the current status of driving while intoxicated prevention strategies-their implementation, impacts and effects-using Brazil as a case example. We propose a three-pronged approach to close this northern-southern American gap in driving while intoxicated prevention and intervention: (a) systematic collection on road traffic crash/injury/death as well as risk factor data, (b) passage of laws without loopholes requiring compliance with blood alcohol concentration testing and (c) provision of appropriate training and equipment to the police in concomitance with vigilant enforcement. Resources and energies must be put towards data collection, implementation of prevention strategies and enforcement in order to decrease the unacceptably high rates of these preventable driving while intoxicated deaths. © 2012 The Authors, Addiction © 2012 Society for the Study of Addiction.

Adolescent Cellphone Use While Driving: An Overview of the Literature and Promising Future Directions for Prevention.

PubMed

Delgado, M Kit; Wanner, Kathryn J; McDonald, Catherine

2016-06-16

Motor vehicle crashes are the leading cause of death in adolescents, and drivers aged 16-19 are the most likely to die in distracted driving crashes. This paper provides an overview of the literature on adolescent cellphone use while driving, focusing on the crash risk, incidence, risk factors for engagement, and the effectiveness of current mitigation strategies. We conclude by discussing promising future approaches to prevent crashes related to cellphone use in adolescents. Handheld manipulation of the phone while driving has been shown to have a 3 to 4-fold increased risk of a near crash or crash, and eye glance duration greater than 2 seconds increases crash risk exponentially. Nearly half of U.S. high school students admit to texting while driving in the last month, but the frequency of use according to vehicle speed and high-risk situations remains unknown. Several risk factors are associated with cell phone use while driving including: parental cellphone use while driving, social norms for quick responses to text messages, and higher levels of temporal discounting. Given the limited effectiveness of current mitigation strategies such as educational campaigns and legal bans, a multi-pronged behavioral and technological approach addressing the above risk factors will be necessary to reduce this dangerous behavior in adolescents.

Adolescent Cellphone Use While Driving: An Overview of the Literature and Promising Future Directions for Prevention

PubMed Central

Delgado, M. Kit; Wanner, Kathryn J.; McDonald, Catherine

2016-01-01

Motor vehicle crashes are the leading cause of death in adolescents, and drivers aged 16–19 are the most likely to die in distracted driving crashes. This paper provides an overview of the literature on adolescent cellphone use while driving, focusing on the crash risk, incidence, risk factors for engagement, and the effectiveness of current mitigation strategies. We conclude by discussing promising future approaches to prevent crashes related to cellphone use in adolescents. Handheld manipulation of the phone while driving has been shown to have a 3 to 4-fold increased risk of a near crash or crash, and eye glance duration greater than 2 seconds increases crash risk exponentially. Nearly half of U.S. high school students admit to texting while driving in the last month, but the frequency of use according to vehicle speed and high-risk situations remains unknown. Several risk factors are associated with cell phone use while driving including: parental cellphone use while driving, social norms for quick responses to text messages, and higher levels of temporal discounting. Given the limited effectiveness of current mitigation strategies such as educational campaigns and legal bans, a multi-pronged behavioral and technological approach addressing the above risk factors will be necessary to reduce this dangerous behavior in adolescents. PMID:27695663

Active-Matrix Organic Light Emission Diode Pixel Circuit for Suppressing and Compensating for the Threshold Voltage Degradation of Hydrogenated Amorphous Silicon Thin Film Transistors

NASA Astrophysics Data System (ADS)

Shin, Hee-Sun; Lee, Won-Kyu; Park, Sang-Guen; Kuk, Seung-Hee; Han, Min-Koo

2009-03-01

A new hydrogenated amorphous silicon (a-Si:H) thin film transistor (TFT) pixel circuit for active-matrix organic light emission diodes (AM-OLEDs), which significantly compensates the OLED current degradation by memorizing the threshold voltage of driving TFT and suppresses the threshold voltage shift of a-Si:H TFTs by negative bias annealing, is proposed and fabricated. During the first half of each frame, the driving TFT of the proposed pixel circuit supplies current to the OLED, which is determined by modified data voltage in the compensation scheme. The proposed pixel circuit was able to compensate the threshold voltage shift of the driving TFT as well as the OLED. During the remaining half of each frame, the proposed pixel circuit induces the recovery of the threshold voltage degradation of a-Si:H TFTs owing to the negative bias annealing. The experimental results show that the proposed pixel circuit was able to successfully compensate for the OLED current degradation and suppress the threshold voltage degradation of the driving TFT.

Comparing treatment effects of oral THC on simulated and on-the-road driving performance: testing the validity of driving simulator drug research.

PubMed

Veldstra, J L; Bosker, W M; de Waard, D; Ramaekers, J G; Brookhuis, K A

2015-08-01

The driving simulator provides a safe and controlled environment for testing driving behaviour efficiently. The question is whether it is sensitive to detect drug-induced effects. The primary aim of the current study was to investigate the sensitivity of the driving simulator for detecting drug effects. As a case in point, we investigated the dose-related effects of oral ∆(9)-tetrahydrocannabinol (THC), i.e. dronabinol, on simulator and on-the-road driving performance in equally demanding driving tasks. Twenty-four experienced driver participants were treated with dronabinol (Marinol®; 10 and 20 mg) and placebo. Dose-related effects of the drug on the ability to keep a vehicle in lane (weaving) and to follow the speed changes of a lead car (car following) were compared within subjects for on-the-road versus in-simulator driving. Additionally, the outcomes of equivalence testing to alcohol-induced effects were investigated. Treatment effects found on weaving when driving in the simulator were comparable to treatment effects found when driving on the road. The effect after 10 mg dronabinol was however less strong in the simulator than on the road and inter-individual variance seemed higher in the simulator. There was, however, a differential treatment effect of dronabinol on reactions to speed changes of a lead car (car following) when driving on the road versus when driving in the simulator. The driving simulator was proven to be sensitive for demonstrating dronabinol-induced effects particularly at higher doses. Treatment effects of dronabinol on weaving were comparable with driving on the road but inter-individual variability seemed higher in the simulator than on the road which may have potential effects on the clinical inferences made from simulator driving. Car following on the road and in the simulator were, however, not comparable.

Spaceborne Studies Of Ocean Circulation

NASA Astrophysics Data System (ADS)

Patzert, William C.

1984-08-01

The global view of the oceans seen by Seasat during its 1978 flight demonstrated the feasibility of ocean remote sensing. These first-ever global data sets of sea surface topography (altimeter) and marine winds (scatterometer) laid the foundation for two satellite missions planned for the late 1980's. The future missions are the next generation of altimeter and scatterometer to be flown aboard TOPEX (Topography Experiment) and NROSS (Navy Remote Ocean Sensing System), respectively. The data from these satellites will be coordinated with measurements made at sea to determine the driving forces of ocean circulation and to study the oceans role in climate variability. Sea surface winds (calculated from scatterometer measurements) are the fundamental driving force for ocean waves and currents (estimated from altimeter measurements). On a global scale, the winds and currents are approximately equal partners in redistributing the excess heat gained in the tropics from solar radiation to the cooler polar regions. Small perturbations in this system can dramatically alter global weather, such as the El Niho event of 1982-83. During an El Ni?io event, global wind patterns and ocean currents are perturbed causing unusual ocean warming in the tropical Pacfic Ocean. These ocean events are coupled to complex fluctuations in global weather. Only with satellites will we be able to collect the global data sets needed to study events such as El Ni?o. When TOPEX and NROSS fly, oceanographers will have the equivalent of meteorological high and low pressure charts of ocean topography as well as the surface winds to study ocean "weather." This ability to measure ocean circulation and its driving forces is a critical element in understanding the influence of oceans on society. Climatic changes, fisheries, commerce, waste disposal, and national defense are all involved.

Fractional Brownian motors and stochastic resonance

NASA Astrophysics Data System (ADS)

Goychuk, Igor; Kharchenko, Vasyl

2012-05-01

We study fluctuating tilt Brownian ratchets based on fractional subdiffusion in sticky viscoelastic media characterized by a power law memory kernel. Unlike the normal diffusion case, the rectification effect vanishes in the adiabatically slow modulation limit and optimizes in a driving frequency range. It is shown also that the anomalous rectification effect is maximal (stochastic resonance effect) at optimal temperature and can be of surprisingly good quality. Moreover, subdiffusive current can flow in the counterintuitive direction upon a change of temperature or driving frequency. The dependence of anomalous transport on load exhibits a remarkably simple universality.

Alcohol consumption patterns and attitudes toward drink-drive behaviours and road safety enforcement strategies.

PubMed

Stephens, A N; Bishop, C A; Liu, S; Fitzharris, M

2017-01-01

Alcohol contributes to approximately 30% of all serious crashes. While the majority of drivers acknowledge the risks associated with drink-driving, a significant proportion of the population continue to engage in this behaviour. Attitudes towards drink-driving as well as personal alcohol consumption patterns are likely to underpin a driver's decision to drink-drive. These associations were explored in the current study. A large (N=2994) cross-sectional online survey of a representative sample of drivers in Australia was conducted. Participants provided information about their own alcohol consumption patterns, drink-driving behaviour as well as attitudes towards drink-driving (own and others) and enforcement strategies. Alcohol consumption patterns differed according to age, gender and work status. Drivers who reported drink-driving behaviour and had high risk alcohol consumption patterns were less likely to agree that drink-driving leads to increased crash risk and more likely to agree they drink and drive when they believed they could get away with it. In contrast, drivers who did not report drink-driving and had low risk consumption patterns were more likely to report that the enforcement strategies are too lenient. Binary logistic regression showed that high risk alcohol consumption patterns and agreement from drivers that they drink and drive when they believe they can get away with it had the strongest associations with drink-driving. These findings highlight the relationships between one's drinking patterns, drink-drive behaviour and attitudes towards drink-driving and drink-driving enforcement CONCLUSIONS AND IMPLICATIONS: The patterns of associations that emerged suggest that drink-driving is the expression of a broader health issue for the most "at-risk" cohort of drinkers. The decision to drink and drive may result from a need borne from an alcohol dependent lifestyle exacerbated by a social acceptability of the behaviour and positive attitudes towards one's ability to drink-drive with few adverse consequences. Therefore, the broader alcohol consumption patterns of drink-drivers needs to be considered when targeting drink-drive reductions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Long-Life, Lightweight, Multi-Roller Traction Drives for Planetary Vehicle Surface Exploration

NASA Technical Reports Server (NTRS)

Klein, Richard C.; Fusaro, Robert L.; Dimofte, Florin

2012-01-01

NASA s initiative for Lunar and Martian exploration will require long lived, robust drive systems for manned vehicles that must operate in hostile environments. The operation of these mechanical drives will pose a problem because of the existing extreme operating conditions. Some of these extreme conditions include operating at a very high or very cold temperature, operating over a wide range of temperatures, operating in very dusty environments, operating in a very high radiation environment, and operating in possibly corrosive environments. Current drive systems use gears with various configurations of teeth. These gears must be lubricated with oil (or grease) and must have some sort of a lubricant resupply system. For drive systems, oil poses problems such as evaporation, becoming too viscous and eventually freezing at cold temperatures, being too thin to lubricate at high temperatures, being degraded by the radiation environment, being contaminated by the regolith (soil), and if vaporized (and not sealed), it will contaminate the regolith. Thus, it may not be advisable or even possible to use oil because of these limitations. An oil-less, compact traction vehicle drive is a drive designed for use in hostile environments like those that will be encountered on planetary surfaces. Initially, traction roller tests in vacuum were conducted to obtain traction and endurance data needed for designing the drives. From that data, a traction drive was designed that would fit into a prototype lunar rover vehicle, and this design data was used to construct several traction drives. These drives were then tested in air to determine their performance characteristics, and if any final corrections to the designs were necessary. A limitation with current speed reducer systems such as planetary gears and harmonic drives is the high-contact stresses that occur at tooth engagement and in the harmonic drive wave generator interface. These high stresses induce high wear of solid lubricant coatings, thus necessitating the use of liquid lubricants for long life.

Driving range estimation for electric vehicles based on driving condition identification and forecast

NASA Astrophysics Data System (ADS)

Pan, Chaofeng; Dai, Wei; Chen, Liao; Chen, Long; Wang, Limei

2017-10-01

With the impact of serious environmental pollution in our cities combined with the ongoing depletion of oil resources, electric vehicles are becoming highly favored as means of transport. Not only for the advantage of low noise, but for their high energy efficiency and zero pollution. The Power battery is used as the energy source of electric vehicles. However, it does currently still have a few shortcomings, noticeably the low energy density, with high costs and short cycle life results in limited mileage compared with conventional passenger vehicles. There is great difference in vehicle energy consumption rate under different environment and driving conditions. Estimation error of current driving range is relatively large due to without considering the effects of environmental temperature and driving conditions. The development of a driving range estimation method will have a great impact on the electric vehicles. A new driving range estimation model based on the combination of driving cycle identification and prediction is proposed and investigated. This model can effectively eliminate mileage errors and has good convergence with added robustness. Initially the identification of the driving cycle is based on Kernel Principal Component feature parameters and fuzzy C referring to clustering algorithm. Secondly, a fuzzy rule between the characteristic parameters and energy consumption is established under MATLAB/Simulink environment. Furthermore the Markov algorithm and BP(Back Propagation) neural network method is utilized to predict the future driving conditions to improve the accuracy of the remaining range estimation. Finally, driving range estimation method is carried out under the ECE 15 condition by using the rotary drum test bench, and the experimental results are compared with the estimation results. Results now show that the proposed driving range estimation method can not only estimate the remaining mileage, but also eliminate the fluctuation of the residual range under different driving conditions.

76 FR 79661 - Privacy Act of 1974; System of Records

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-22

... Advertising, Market Research & Studies (JAMRS) Survey Database (July 23, 2008, 73 FR 42786). Changes..., Marketing Research & Studies (JAMRS), Attn: Survey Project Officer, Suite 06J25, 4800 Mark Center Drive... recruitment. However, because opt-out screening is based, in part, on the current address of the individual...

A model of Beijing drivers' scrambling behaviors.

PubMed

Shi, Jing; Bai, Yun; Tao, Li; Atchley, Paul

2011-07-01

A major, but unstudied, cause of crashes in China is drivers that "scramble" to gain the right of way in violation of traffic regulations. The motivation of this study is to explore the features of drivers' scrambling behaviors and the attitudes and driving skills that influence them. In this study, we established a scrambling behavior scale, and developed a driving attitude scale and a driving skill scale using factor analysis of an Internet survey of 486 drivers in Beijing. A structural equation model of scrambling behavior toward cars and pedestrians/cyclists was developed with attitudes and skills as predictors of behavior. Skills and attitudes of approval toward violations of traffic rules did not predict scrambling behaviors, while the motivation for safety and attitudes against violating traffic rules led to reduced scrambling behaviors. The current work highlights this peculiar aspect of Chinese roads and suggests methods to reduce the behavior. Copyright © 2011 Elsevier Ltd. All rights reserved.

Analysis of field-oriented controlled induction motor drives under sensor faults and an overview of sensorless schemes.

PubMed

Arun Dominic, D; Chelliah, Thanga Raj

2014-09-01

To obtain high dynamic performance on induction motor drives (IMD), variable voltage and variable frequency operation has to be performed by measuring speed of rotation and stator currents through sensors and fed back them to the controllers. When the sensors are undergone a fault, the stability of control system, may be designed for an industrial process, is disturbed. This paper studies the negative effects on a 12.5 hp induction motor drives when the field oriented control system is subjected to sensor faults. To illustrate the importance of this study mine hoist load diagram is considered as shaft load of the tested machine. The methods to recover the system from sensor faults are discussed. In addition, the various speed sensorless schemes are reviewed comprehensively. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Combination spindle-drive system for high precision machining

DOEpatents

Gerth, Howard L.

1977-07-26

A combination spindle-drive is provided for fabrication of optical quality surface finishes. Both the spindle-and-drive utilize the spindle bearings for support, thereby removing the conventional drive-means bearings as a source of vibration. An airbearing spindle is modified to carry at the drive end a highly conductive cup-shaped rotor which is aligned with a stationary stator to produce torque in the cup-shaped rotor through the reaction of eddy currents induced in the rotor. This arrangement eliminates magnetic attraction forces and all force is in the form of torque on the cup-shaped rotor.

Where the Rubber Hits the Road: What Home Healthcare Professionals Need to Know About Driving Safety for Persons With Dementia.

PubMed

Pastor, Diane K; Jones, Andrea; Arms, Tamatha

2017-01-01

Driving cessation for people with dementia is a significant personal safety and public health issue. Home healthcare professionals frequently encounter situations where patients/clients should not continue to drive, and family members are unaware of how to approach the issue. This article will inform readers of the current state of the healthcare driving assessment process, measures and instruments used to assess, and effective strategies and resources when working with families facing the dilemma of how and when to proceed with a driving cessation plan.

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

Chung, Donald; Elgqvist, Emma; Santhanagopalan, Shriram

Manufacturing capacity for lithium-ion batteries (LIBs) — which power many consumer electronics and are increasingly used to power electric vehicles — is heavily concentrated in East Asia. To illuminate the factors that drive regional competitiveness in automotive LIB cell production, this study models cell manufacturing cost and minimum sustainable price, and examines development of LIB supply chains and current LIB market conditions. The study shows that factors driving the cost competitiveness of LIB manufacturing locations are mostly built—supply chain developments and competition, access to materials, and production expertise. Some regional costs — including cost of capital, labor, and materials —more » are significant and should be considered.« less

Current drive by spheromak injection into a tokamak

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

Brown, M.R.; Bellan, P.M.

1990-04-30

We report the first observation of current drive by injection of a spheromak plasma into a tokamak (Caltech ENCORE small reasearch tokamak) due to the process of helicity injection. After an abrupt 30% increase, the tokamak current decays by a factor of 3 due to plasma cooling caused by the merging of the relatively cold spheromak with the tokamak. The tokamak density profile peaks sharply due to the injected spheromak plasma ({ital {bar n}}{sub 3} increases by a factor of 6) then becomes hollow, suggestive of an interchange instability.

Ocular disease and driving.

PubMed

Wood, Joanne M; Black, Alex A

2016-09-01

As the driving population ages, the number of drivers with visual impairment resulting from ocular disease will increase given the age-related prevalence of ocular disease. The increase in visual impairment in the driving population has a number of implications for driving outcomes. This review summarises current research regarding the impact of common ocular diseases on driving ability and safety, with particular focus on cataract, glaucoma, age-related macular degeneration, hemianopia and diabetic retinopathy. The evidence considered includes self-reported driving outcomes, driving performance (on-road and simulator-based) and various motor vehicle crash indices. Collectively, this review demonstrates that driving ability and safety are negatively affected by ocular disease; however, further research is needed in this area. Older drivers with ocular disease need to be aware of the negative consequences of their ocular condition and in the case where treatment options are available, encouraged to seek these earlier for optimum driving safety and quality of life benefits. © 2016 Optometry Australia.

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.

Improvement of Current Drive Efficiency in Projected FNSF Discharges

NASA Astrophysics Data System (ADS)

Prater, R.; Chan, V.; Garofalo, A.

2012-10-01

The Fusion Nuclear Science Facility - Advanced Tokamak (FNSF-AT) is envisioned as a facility that uses the tokamak approach to address the development of the AT path to fusion and fusion's energy objectives. It uses copper coils for a compact device with high βN and moderate power gain. The major radius is 2.7 m and central toroidal field is 5.44 T. Achieving the required confinement and stability at βN˜3.7 requires a current profile with negative central shear and qmin>1. Off-axis Electron Cyclotron Current Drive (ECCD), in addition to high bootstrap current fraction, can help support this current profile. Using the applied EC frequency and launch location as free parameters, a systematic study has been carried out to optimize the ECCD in the range ρ= 0.5-0.7. Using a top launch, making use of a large toroidal component to the launch direction, adjusting the vertical launch angle so that the rays propagate nearly parallel to the resonance, and adjusting the frequency for optimum total current give a high dimensionless efficiency of 0.44 for a broad ECCD profile peaked at ρ=0.7, and the driven current is 17 kA/MW for n20= 2.1 and Te= 10.3 keV locally.

Driving and Epilepsy: a Review of Important Issues.

PubMed

Kang, Joon Y; Mintzer, Scott

2016-09-01

Driving restrictions in people with epilepsy (PWE) is a highly contentious topic. The fundamental difficulty lies in achieving a balance between safety and practicality. The aim of this review is to provide an overview, history, and rationale behind current laws regarding driving restriction in PWE. We also discuss recent findings that may be helpful to practitioners during individual discussions with PWE including seizure recurrence risk after first seizure, recurrent seizure, and anticonvulsant with drawl and driving restrictions in patients with psychogenic non-epileptic seizures (PNES).

Scanning tunneling spectroscopy under large current flow through the sample.

PubMed

Maldonado, A; Guillamón, I; Suderow, H; Vieira, S

2011-07-01

We describe a method to make scanning tunneling microscopy/spectroscopy imaging at very low temperatures while driving a constant electric current up to some tens of mA through the sample. It gives a new local probe, which we term current driven scanning tunneling microscopy/spectroscopy. We show spectroscopic and topographic measurements under the application of a current in superconducting Al and NbSe(2) at 100 mK. Perspective of applications of this local imaging method includes local vortex motion experiments, and Doppler shift local density of states studies.

Application of very high harmonic fast waves for off-axis current drive in the DIII-D and FNSF-AT tokamaks

DOE PAGES

Prater, Ronald; Moeller, Charles P.; Pinsker, Robert I.; ...

2014-06-26

Fast waves at frequencies far above the ion cyclotron frequency and approaching the lower hybrid frequency (also called “helicons” or “whistlers”) have application to off-axis current drive in tokamaks with high electron beta. The high frequency causes the whistler-like behavior of the wave power nearly following field lines, but with a small radial component, so the waves spiral slowly toward the plasma center. The high frequency also contributes to strong damping. Modeling predicts robust off-axis current drive with good efficiency compared to alternatives in high performance discharges in DIII-D and Fusion Nuclear Science Facility (FNSF) when the electron beta ismore » above about 1.8%. Detailed analysis of ray behavior shows that ray trajectories and damping are deterministic (that is, not strongly affected by plasma profiles or initial ray conditions), unlike the chaotic ray behavior in lower frequency fast wave experiments. Current drive was found to not be sensitive to the launched value of the parallel index of refraction n||, so wave accessibility issues can be reduced. Finally, use of a traveling wave antenna provides a very narrow n|| spectrum, which also helps avoid accessibility problems.« less

Electron Cyclotron Current Drive Efficiency in General Tokamak Geometry and Its Application to Advanced Tokamak Plasmas

NASA Astrophysics Data System (ADS)

Lin-Liu, Y. R.; Chan, V. S.; Luce, T. C.; Prater, R.

1998-11-01

Owing to relativistic mass shift in the cyclotron resonance condition, a simple and accurate interpolation formula for estimating the current drive efficiency, such as those(S.C. Chiu et al.), Nucl. Fusion 29, 2175 (1989).^,(D.A. Ehst and C.F.F. Karney, Nucl. Fusion 31), 1933 (1991). commonly used in FWCD, is not available in the case of ECCD. In this work, we model ECCD using the adjoint techniques. A semi-analytic adjoint function appropriate for general tokamak geometry is obtained using Fisch's relativistic collision model. Predictions of off-axis ECCD qualitatively and semi-quantitatively agrees with those of Cohen,(R.H. Cohen, Phys. Fluids 30), 2442 (1987). currently implemented in the raytracing code TORAY. The dependences of the current drive efficiency on the wave launch configuration and the plasma parameters will be presented. Strong absorption of the wave away from the resonance layer is shown to be an important factor in optimizing the off-axis ECCD for application to advanced tokamak operations.

The Influence of the Transportation Environment on Driving Reduction and Cessation.

PubMed

Vivoda, Jonathon M; Heeringa, Steven G; Schulz, Amy J; Grengs, Joe; Connell, Cathleen M

2017-10-01

Driving is by far the most common mode of transportation in the United States, but driving ability is known to decline as people experience age-related functional declines. Some older adults respond to such declines by self-limiting their driving to situations with a low perceived risk of crashing, and many people eventually stop driving completely. Previous research has largely focused on individual and interpersonal predictors of driving reduction and cessation (DRC). The purpose of this study was to assess the influence of the transportation environment on DRC. Data were combined from the Health and Retirement Study, the Urban Mobility Scorecard, and StreetMap North America (GIS data). Longitudinal survival analysis techniques were used to analyze seven waves of data spanning a 12-year period. As roadway density and congestion increased in the environment, the odds of DRC also increased, even after controlling for individual and interpersonal predictors. Other predictors of DRC included demographics, relationship status, health, and household size. The current study identified an association between the transportation environment and DRC. Future research is needed to determine whether a causal link can be established. If so, modifications to the physical environment (e.g., creating livable communities with goods and services in close proximity) could reduce driving distances in order to improve older drivers' ability to remain engaged in life. In addition, older individuals who wish to age in place should consider how their local transportation environment may affect their quality of life. © The Author 2016. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Assessment and rehabilitation of driver skills: subjective experiences of people with multiple sclerosis and health professionals.

PubMed

Archer, Cherie; Morris, Libby; George, Stacey

2014-01-01

It is acknowledged in the literature that the physical and cognitive effects of the degenerative neurological condition of multiple sclerosis can impact upon driver safety. The aim of this study was to identify the experiences and needs of people with multiple sclerosis in relation to driver assessment and rehabilitation. Focus group discussions were conducted with people with multiple sclerosis (MS) who were: currently driving; no longer licensed or no longer driving and health professionals. The four themes that emerged from the data were: (1) from self-management to formal assessment - a journey of uncertainty and emotional dilemmas; (2) lost independence with grieving and adjustment by self and family; (3) alternative transport is challenging and unsatisfactory; (4) gaps in information and services exist. The results of this study highlight the need for ongoing support in relation to driving for people with MS, ranging from support for self-management, driving assessment and retraining, and preparation for loss of license. Standardised information needs to be developed and health professionals and licensing authorities require knowledge and skills to ensure driver assessment and rehabilitation processes and resources can better meet the needs of people with MS. There is a need for health professionals to examine driving in people with MS in a holistic manner taking into account the context for the person and the supports available. Self-management and self-assessment emerged as a preferred approach for the participants in this study, indicating that health professionals may need to engage with the process. Tools to support self-assessment of driving abilities for people with MS require further research. Indicators for review and formal assessment of driving abilities is needed. Alternative forms of transport require further investigation and improvement for people with MS.

The relationship of written examination performance to safe driving : a literature review with recommended methods for developing exams.

DOT National Transportation Integrated Search

1984-01-01

This report reviews the literature concerning written driver license examinations. The research literature shows that current written examinations are poor predictors of unsafe drivers. Although some studies demonstrate significant relationships betw...

Eco-driving behavior tendency among Indonesian people: a preliminary study

NASA Astrophysics Data System (ADS)

Zuraida, Rida; Widjaja, Dimitrius

2017-12-01

Eco-driving behavior can be triggered by many aspects such as economic and environmental awareness. In Indonesia this issue received less attention from citizen, whereas it has significant roles in reducing greenhouse gas emission. This paper initiated a study about eco-driving tendency behavior among Indonesian people, the objective is to see whether current behavior support or not, and does the differences between gender and age exist. Adopted on-line study method using an online form questionnaire„ 27 questions developed consist of 8 items related to individual data, 19 items related to perception and driving behavior. The respond measures using 5 scale option answers (i.e. strongly disagree, disagree, quite agree, agree, and strongly agree). Based on average respondents’ answers, can be concluded that the tendency of behavior somewhat supports to in line with eco-driving behavior. After Q15 and Q18 omitted based on Pearson-product moment correlation, further analysis results showed that most of respondents categorized into mild tendency behavior (109 respondents). However, a mild tendency among female respondents are higher than male, and the strong tendency of males is higher than female respondents. Based on gender, there are no significant tendency behavior differences between male and female (p-value = 0, 320), and also among age groups (30y, 31-40y, 41-50y, and >50y), even though age >50 have a lower tendency to the behavior compare to other groups.

Investigation of dynamic driving cycle effect on the degradation of proton exchange membrane fuel cell by segmented cell technology

NASA Astrophysics Data System (ADS)

Lin, R.; Xiong, F.; Tang, W. C.; Técher, L.; Zhang, J. M.; Ma, J. X.

2014-08-01

Durability is one of the most important limiting factors for the commercialization of proton exchange membrane fuel cell (PEMFC). Fuel cells are more vulnerable to degradation under operating conditions as dynamic load cycle or start up/shut down. The purpose of this study is to evaluate influences of driving cycles on the durability of fuel cells through analyzing the degradation mechanism of a segmented cell in real time. This study demonstrates that the performance of the fuel cell significantly decreases after 200 cycles. The segmented cell technology is used to measure the local current density distribution, which shows that the current density at the exit region and the inlet region declines much faster than the other parts. Meanwhile, electro-chemical impedance spectroscopy (EIS) reveals that after 200 cycles the ohmic resistance of fuel cell increases, especially at the cathode, and electro-chemical surface area (ESA) decreases from 392 to 307 cm2 mg-1. Furthermore, scanning electron microscopy (SEM) images of the membrane-electrode assembly (MEA) in cross-section demonstrate crackle flaw on the surface of the catalyst layer and the delamination of the electrodes from the membrane. Transmission electron microscope (TEM) results also show that the Pt particle size increases distinctly after driving cycles.

Are Sex Drive and Hypersexuality Associated with Pedophilic Interest and Child Sexual Abuse in a Male Community Sample?

PubMed Central

Klein, Verena; Schmidt, Alexander F.; Turner, Daniel; Briken, Peer

2015-01-01

Although much is currently known about hypersexuality (in the form of excessive sexual behavior) among sexual offenders, the degree to which hypersexual behavior is linked to paraphilic and especially pedophilic interests in non-forensic populations has not been established. The purpose of the present study was to elucidate the associations between total sexual outlets (TSO) and other sex drive indicators, antisocial behavior, pedophilic interests, and sexual offending behavior in a large population-based community sample of males. The sample included 8,718 German men who participated in an online study. Hypersexual behavior as measured by self-reported TSO, self-reported sex drive, criminal history, and pedophilic interests were assessed. In moderated hierarchical logistic regression analyses self-reported contact sexual offending against children was linked to sexual fantasizing about children and antisociality. There was no association between aggregated sex drive, and sexual abusive behaviour in the multivariate analyses. In contrast, self-reported child pornography consumption was associated with sex drive, sexual fantasies involving children, and antisociality. Nevertheless, in clinical practice an assessment of criminal history and pedophilic interests in hypersexual individuals and vice versa hypersexuality in antisocial or pedophilic men should be considered as particularly antisociality and pedophilic interest are important predictors of sexual offending against prepubescent children. PMID:26147099

Experimental evaluation of hybrid vehicle fuel economy and pollutant emissions over real-world simulation driving cycles

NASA Astrophysics Data System (ADS)

Fontaras, Georgios; Pistikopoulos, Panayotis; Samaras, Zissis

2008-06-01

The reduction of transport-generated CO2 emissions is currently a problem of global interest. Hybrid electric vehicles (HEVs) are considered as one promising technological solution for limiting transport-generated greenhouse gas emissions. Currently, the number of HEVs in the market remains limited, but this picture will change in the years to come as HEVs are expected to pave the way for cleaner technologies in transport. In this paper, results are presented regarding fuel economy and pollutant emissions measurements of two hybrid electric production vehicles. The measurements were conducted on a Prius II and a Honda Civic IMA using both the European legislated driving cycle (New European Driving Cycle, NEDC) and real-world simulation driving cycles (Artemis). In addition to the emissions measurements, other vehicle-operating parameters were studied in an effort to better quantify the maximum CO2 reduction potential. Data from real-world operation of a Prius II vehicle were also used in the evaluation. Results indicate that in most cases both vehicles present improved energy efficiency and pollutant emissions compared to conventional cars. The fuel economy benefit of the two HEVs peaked under urban driving conditions where reductions of 60% and 40% were observed, respectively. Over higher speeds the difference in fuel economy was lower, reaching that of conventional diesel at 95 km h-1. The effect of ambient temperature on fuel consumption was also quantified. It is concluded that urban operation benefits the most of hybrid technology, leading to important fuel savings and urban air quality improvement.

Flexible integrated diode-transistor logic (DTL) driving circuits based on printed carbon nanotube thin film transistors with low operation voltage.

PubMed

Liu, Tingting; Zhao, Jianwen; Xu, Weiwei; Dou, Junyan; Zhao, Xinluo; Deng, Wei; Wei, Changting; Xu, Wenya; Guo, Wenrui; Su, Wenming; Jie, Jiansheng; Cui, Zheng

2018-01-03

Fabrication and application of hybrid functional circuits have become a hot research topic in the field of printed electronics. In this study, a novel flexible diode-transistor logic (DTL) driving circuit is proposed, which was fabricated based on a light emitting diode (LED) integrated with printed high-performance single-walled carbon nanotube (SWCNT) thin-film transistors (TFTs). The LED, which is made of AlGaInP on GaAs, is commercial off-the-shelf, which could generate free electrical charges upon white light illumination. Printed top-gate TFTs were made on a PET substrate by inkjet printing high purity semiconducting SWCNTs (sc-SWCNTs) ink as the semiconductor channel materials, together with printed silver ink as the top-gate electrode and printed poly(pyromellitic dianhydride-co-4,4'-oxydianiline) (PMDA/ODA) as gate dielectric layer. The LED, which is connected to the gate electrode of the TFT, generated electrical charge when illuminated, resulting in biased gate voltage to control the TFT from "ON" status to "OFF" status. The TFTs with a PMDA/ODA gate dielectric exhibited low operating voltages of ±1 V, a small subthreshold swing of 62-105 mV dec -1 and ON/OFF ratio of 10 6 , which enabled DTL driving circuits to have high ON currents, high dark-to-bright current ratios (up to 10 5 ) and good stability under repeated white light illumination. As an application, the flexible DTL driving circuit was connected to external quantum dot LEDs (QLEDs), demonstrating its ability to drive and to control the QLED.

Veff Scaling of Te and ne Measurements During Local Helicity Injection on the Pegasus Toroidal Experiment

NASA Astrophysics Data System (ADS)

Bodner, G. M.; Bongard, M. W.; Fonck, R. J.; Perry, J. M.; Reusch, J. A.; Rodriguez Sanchez, C.

2017-10-01

Understanding the electron confinement of local helicity injection (LHI) is critical in order to evaluate its scalability as a startup technique to MA-class devices. Electron confinement in the Pegasus Toroidal Experiment is investigated using multi-point Thomson scattering (TS). The Pegasus TS system utilizes a set of high-throughput transmission gratings and intensified CCDs to measure Te and ne profiles. Previous TS measurements indicated peaked Te profiles 120 eV in outboard injector discharges characterized by strong inductive drive and low LHI drive. Injectors designed to have dominant non-inductive drive have recently been installed in the divertor region of Pegasus to understand the relationship between effective drive voltage, Veff, and plasma performance. At low Veff and reduced plasma current, Ip 60 kA, TS measurements reveal a flat Te profile 50 eV, with a peaked ne profile 1 ×1019 m-3, resulting in a slightly peaked pe profile. As current drive is increased, the Te profiles become hollow with a core Te 50 eV and an edge Te 120 -150 eV. These hollow profiles appear after the start of the Ip flattop and are sustained until the discharge terminates. The ne profiles drop in magnitude to < 1 ×1019 m-3 but remain somewhat peaked. Initial results suggest a weak scaling between input power and core Te. Additional studies are planned to identify the mechanisms behind the anomalous profile features. Work supported by US DOE Grant DE-FG02-96ER54375.

Dimensionless factors for an alternating-current non-thermal arc plasma

NASA Astrophysics Data System (ADS)

Zhang, Si-Yuan; Li, Xiao-Song; Liu, Jin-Bao; Liu, Jing-Lin; Li, He-Ping; Zhu, Ai-Min

2016-12-01

A gliding arc discharge, as a source of warm plasma combining advantages of both thermal and cold plasmas, would have promising application prospects in the fields of fuel conversion, combustion enhancement, material synthesis, surface modifications, pollution control, etc. In order to gain insight into the features of an alternating-current gliding arc discharge plasma, three dimensionless factors, i.e., the extinction span (ψ), current lag (δ), and heating lag (χ) factors are proposed in this letter based on the measured waveforms of the discharge voltage and current in an AC gliding arc discharge plasma. The influences of the driving frequency of the power supply (f) on these three dimensionless parameters are investigated experimentally with the explanations on the physical meanings of these factors. The experimental results show that a higher value of f would lead to the lower values of ψ and δ, as well as a higher value of χ. These experimental phenomena indicate a lower threshold ignition voltage of the discharges, a lower current-growth inertia of the gliding arcs and a larger relative thermal inertia of the plasmas with increase the driving frequency of the power supply in the operating parameter range studied in this letter.

Numerical modeling of lower hybrid current drive in fully non-inductive plasma start-up experiments on TST-2

NASA Astrophysics Data System (ADS)

Tsujii, N.; Takase, Y.; Ejiri, A.; Shinya, T.; Togashi, H.; Yajima, S.; Yamazaki, H.; Moeller, C. P.; Roidl, B.; Sonehara, M.; Takahashi, W.; Toida, K.; Yoshida, Y.

2017-12-01

Non-inductive plasma start-up is a critical issue for spherical tokamaks since there is not enough room to provide neutron shielding for the center solenoid. Start-up using lower hybrid (LH) waves has been studied on the TST-2 spherical tokamak. Because of the low magnetic field of a spherical tokamak, the plasma density needs to be kept at a very low value during the plasma current ramp-up so that the plasma core remains accessible to the LH waves. However, we have found that higher density was required to sustain larger plasma current. The achievable plasma current was limited by the maximum operational toroidal field of TST-2. The existence of an optimum density for LH current drive and its toroidal field dependence is explained through a numerical simulation based on a ray tracing code and a Fokker-Planck solver. In order to access higher density at the same magnetic field, a top-launch antenna was recently installed in addition to the existing outboard-launch antenna. Increase in the density limit was observed when the power was launched from the top antenna, consistently with the numerical predictions.

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.

System and method for determining stator winding resistance in an AC motor using motor drives

DOEpatents

Lu, Bin; Habetler, Thomas G; Zhang, Pinjia

2013-02-26

A system and method for determining the stator winding resistance of AC motors is provided. The system includes an AC motor drive having an input connectable to an AC source and an output connectable to an input terminal of an AC motor, a pulse width modulation (PWM) converter having switches therein to control current flow and terminal voltages in the AC motor, and a control system connected to the PWM converter. The control system generates a command signal to cause the PWM converter to control an output of the AC motor drive corresponding to an input to the AC motor, selectively generates a modified command signal to cause the PWM converter to inject a DC signal into the output of the AC motor drive, and determines a stator winding resistance of the AC motor based on the DC signal of at least one of the voltage and current.

Improvement in Brightness Uniformity by Compensating for the Threshold Voltages of Both the Driving Thin-Film Transistor and the Organic Light-Emitting Diode for Active-Matrix Organic Light-Emitting Diode Displays

NASA Astrophysics Data System (ADS)

Ching-Lin Fan,; Hui-Lung Lai,; Jyu-Yu Chang,

2010-05-01

In this paper, we propose a novel pixel design and driving method for active-matrix organic light-emitting diode (AM-OLED) displays using low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs). The proposed threshold voltage compensation circuit, which comprised five transistors and two capacitors, has been verified to supply uniform output current by simulation work using the automatic integrated circuit modeling simulation program with integrated circuit emphasis (AIM-SPICE) simulator. The driving scheme of this voltage programming method includes four periods: precharging, compensation, data input, and emission. The simulated results demonstrate excellent properties such as low error rate of OLED anode voltage variation (<1%) and high output current. The proposed pixel circuit shows high immunity to the threshold voltage deviation characteristics of both the driving poly-Si TFT and the OLED.

Microturbulence studies of pulsed poloidal current drive discharges in the reversed field pinch

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

Carmody, D., E-mail: dcarmody@wisc.edu; Pueschel, M. J.; Anderson, J. K.

2015-01-15

Experimental discharges with pulsed poloidal current drive (PPCD) in the Madison Symmetric Torus reversed field pinch are investigated using a semi-analytic equilibrium model in the gyrokinetic turbulence code GENE. PPCD cases, with plasma currents of 500 kA and 200 kA, exhibit a density-gradient-driven trapped electron mode (TEM) and an ion temperature gradient mode, respectively. Relative to expectations of tokamak core plasmas, the critical gradients for the onset of these instabilities are found to be greater by roughly a factor of the aspect ratio. A significant upshift in the nonlinear TEM transport threshold, previously found for tokamaks, is confirmed in nonlinear reversed fieldmore » pinch simulations and is roughly three times the threshold for linear instability. The simulated heat fluxes can be brought in agreement with measured diffusivities by introducing a small, resonant magnetic perturbation, thus modeling the residual fluctuations from tearing modes. These fluctuations significantly enhance transport.« less

Development of the pump protection system against cavitation on the basis of the stator current signature analysis of drive electric motor

NASA Astrophysics Data System (ADS)

Kipervasser, M. V.; Gerasimuk, A. V.; Simakov, V. P.

2018-05-01

In the present paper a new registration method of such inadmissible phenomenon as cavitation in the operating mode of centrifugal pump is offered. Influence of cavitation and extent of its development on the value of mechanical power consumed by the pump from the electric motor is studied. On the basis of design formulas the joint mathematical model of centrifugal pumping unit with the synchronous motor is created. In the model the phenomena accompanying the work of a pumping installation in the cavitation mode are considered. Mathematical modeling of the pump operation in the considered emergency operation is carried out. The chart of stator current of the electric motor, depending on the degree of cavitation development of is received. On the basis of the analysis of the obtained data the conclusion on the possibility of registration of cavitation by the current of drive electric motor is made and the functional diagram of the developed protection system is offered, its operation principle is described.

Trapped fast particle destabilization of internal kink mode for the locally flattened q-profile with an inflection point

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

Wang, Xian-Qu; Zhang, Rui-Bin; Meng, Guo

2016-07-15

The destabilization of ideal internal kink modes by trapped fast particles in tokamak plasmas with a “shoulder”-like equilibrium current is investigated. It is found that energetic particle branch of the mode is unstable with the driving of fast-particle precession drifts and corresponds to a precessional fishbone. The mode with a low stability threshold is also more easily excited than the conventional precessional fishbone. This is different from earlier studies for the same equilibrium in which the magnetohydrodynamic (MHD) branch of the mode is stable. Furthermore, the stability and characteristic frequency of the mode are analyzed by solving the dispersion relationmore » and comparing with the conventional fishbone. The results suggest that an equilibrium with a locally flattened q-profile, may be modified by localized current drive (or bootstrap current, etc.), is prone to the onset of the precessional fishbone branch of the mode.« less

Emergence of Huge Negative Spin-Transfer Torque in Atomically Thin Co layers

NASA Astrophysics Data System (ADS)

Je, Soong-Geun; Yoo, Sang-Cheol; Kim, Joo-Sung; Park, Yong-Keun; Park, Min-Ho; Moon, Joon; Min, Byoung-Chul; Choe, Sug-Bong

2017-04-01

Current-induced domain wall motion has drawn great attention in recent decades as the key operational principle of emerging magnetic memory devices. As the major driving force of the motion, the spin-orbit torque on chiral domain walls has been proposed and is currently extensively studied. However, we demonstrate here that there exists another driving force, which is larger than the spin-orbit torque in atomically thin Co films. Moreover, the direction of the present force is found to be the opposite of the prediction of the standard spin-transfer torque, resulting in the domain wall motion along the current direction. The symmetry of the force and its peculiar dependence on the domain wall structure suggest that the present force is, most likely, attributed to considerable enhancement of a negative nonadiabatic spin-transfer torque in ultranarrow domain walls. Careful measurements of the giant magnetoresistance manifest a negative spin polarization in the atomically thin Co films which might be responsible for the negative spin-transfer torque.

Investigation on deterrence effect of legal punishment measures on driving after drinking in Chongqing, China.

PubMed

Suo, Qinghui

2015-01-01

Driving after drinking is one of the main causes associated with road accidents in China. China has been concerned about this serious problem and updated the regulations of road traffic safety law about driving after drinking 3 times in the last 10 years to deter this offense. The deterrence effect of the current punishment measures implemented since January 2013 was studied in this article. Data applied in the study were collected by questionnaire surveys carried out in Chongqing, a city in southwest China. A total of 329 drivers participated in 3 rounds of the survey and a 5-point scale rating was applied in the investigation. There was a slight difference between drivers' familiarity of the law regarding driving after drinking in April 2013 and April 2014. The perceived certainty of being caught for driving after drinking was higher in April 2013 than in April 2014 and it had a time-dependent decreasing tendency. Our investigations also show that license suspension is the most practical and effective measure and penalty points system ranks second. A monetary fine appears to be inefficient to achieve the desired effects. The fourth edition of the Road Traffic Safety Law of the People's Republic of China, which took effect in January 2013 coinciding with the application of random breath testing and intensification of enforcement activity, is effective in deterring driving after drinking according to our investigation. More measures should be implemented to change the decreasing tendency of perceived certainty of being caught for driving after drinking. An increase in the monetary fine is suggested.

TFT-Directed Electroplating of RGB Luminescent Films without a Vacuum or Mask toward a Full-Color AMOLED Pixel Matrix.

PubMed

Wang, Rong; Zhang, Donglian; Xiong, You; Zhou, Xuehong; Liu, Cao; Chen, Weifeng; Wu, Weijing; Zhou, Lei; Xu, Miao; Wang, Lei; Liu, Linlin; Peng, Junbiao; Ma, Yuguang; Cao, Yong

2018-05-30

The thin-film transistor (TFT) driving circuit is a separate electronic component embedded within the panel itself to switch the current for each pixel in active-matrix organic light-emitting diode displays. We reported a TFT-directed dye electroplating method to fabricate pixels; this would be a new method to deposit films on prepatterned electrode for organic full-color display, where TFT driving circuit provide a switching current signal to drive and direct dye depositing on selected RGB pixels. A prototype patterned color pixel matrix was achieved, as high-quality light-emitting films with uniform morphology, pure RGB chromaticity, and stable output.

Electric machine and current source inverter drive system

DOEpatents

Hsu, John S

2014-06-24

A drive system includes an electric machine and a current source inverter (CSI). This integration of an electric machine and an inverter uses the machine's field excitation coil for not only flux generation in the machine but also for the CSI inductor. This integration of the two technologies, namely the U machine motor and the CSI, opens a new chapter for the component function integration instead of the traditional integration by simply placing separate machine and inverter components in the same housing. Elimination of the CSI inductor adds to the CSI volumetric reduction of the capacitors and the elimination of PMs for the motor further improve the drive system cost, weight, and volume.

Modelling of piezoelectric actuator dynamics for active structural control

NASA Technical Reports Server (NTRS)

Hagood, Nesbitt W.; Chung, Walter H.; Von Flotow, Andreas

1990-01-01

The paper models the effects of dynamic coupling between a structure and an electrical network through the piezoelectric effect. The coupled equations of motion of an arbitrary elastic structure with piezoelectric elements and passive electronics are derived. State space models are developed for three important cases: direct voltage driven electrodes, direct charge driven electrodes, and an indirect drive case where the piezoelectric electrodes are connected to an arbitrary electrical circuit with embedded voltage and current sources. The equations are applied to the case of a cantilevered beam with surface mounted piezoceramics and indirect voltage and current drive. The theoretical derivations are validated experimentally on an actively controlled cantilevered beam test article with indirect voltage drive.

Prefrontal transcranial direct current stimulation improves fundamental vehicle control abilities.

PubMed

Sakai, Hiroyuki; Uchiyama, Yuji; Tanaka, Satoshi; Sugawara, Sho K; Sadato, Norihiro

2014-10-15

Noninvasive brain stimulation techniques have increasingly attracted the attention of neuroscientists because they enable the identification of the causal role of a targeted brain region. However, few studies have applied such techniques to everyday life situations. Here, we investigate the causal role of the dorsolateral prefrontal cortex (DLPFC) in fundamental vehicle control abilities. Thirteen participants underwent a simulated driving task under prefrontal transcranial direct current stimulation (tDCS) on three separate testing days. Each testing day was randomly assigned to either anodal over the right with cathodal over the left DLPFC, cathodal over the right with anodal over the left DLPFC, or sham stimulation. The driving task required the participants to maintain an inter-vehicle distance to a leading car traveling a winding road with a constant speed. Driving performance was quantified using two metrics: the root-mean-square error of inter-vehicle distance as car-following performance, and the standard deviation of lateral position as lane-keeping performance. Results showed that both car-following and lane-keeping performances were significantly greater for right anodal/left cathodal compared with right cathodal/left cathodal and sham stimulation. These results suggest not only the causal involvement of the DLPFC in driving, but also right hemisphere dominance for vehicle control. The findings of this study indicate that tDCS can be a useful tool to examine the causal role of a specific brain region in ecologically valid environments, and also might be a help to drivers with difficulties in vehicle control. Copyright © 2014 Elsevier B.V. All rights reserved.

Why Do Drivers Use Mobile Phones While Driving? The Contribution of Compensatory Beliefs.

PubMed

Zhou, Ronggang; Yu, Mengli; Wang, Xinyi

2016-01-01

The current study is the first to investigate the contribution of compensatory beliefs (i.e., the belief that the negative effects of an unsafe behavior can be "neutralized" by engaging in another safe behavior; e.g., "I can use a mobile phone now because I will slow down ") on drivers' mobile phone use while driving. The effects of drivers' personal characteristics on compensatory beliefs, mobile phone use and self-regulatory behaviors were also examined. A series of questions were administered to drivers, which included (1) personal measures, (2) scales that measured compensatory beliefs generally in substance use and with regard to driving safety, and (3) questions to measure drivers' previous primary mobile phone usage and corresponding self-regulatory actions. Overall, drivers reported a low likelihood of compensatory beliefs, prior mobile phone use, and a strong frequency of self-regulatory behaviors. Respondents who had a higher tendency toward compensatory beliefs reported more incidents or crash involvement caused by making or answering calls and sending or reading messages. The findings provide strong support for the contribution of compensatory beliefs in predicting mobile phone usage in the context of driving. Compensatory beliefs can explain 41% and 43% of the variance in the active activities of making calls and texting/sending messages compared with 18% and 31% of the variance in the passive activities of answering calls and reading messages. Among the regression models for predicting self-regulatory behaviors at the tactical or operational level, compensatory beliefs emerge as significant predictors only in predicting shorter conversations while on a call. The findings and limitations of the current study are discussed.

Weber electrodynamics, part I. general theory, steady current effects

NASA Astrophysics Data System (ADS)

Wesley, J. P.

1990-10-01

The original Weber action at a distance theory, valid for slowly varying effects, is extended to time-retarded fields, valid for rapidly varying effects including radiation. A new law for the force on a charge moving in this field is derived (replacing the Lorentz force which violates Newton's third law). The limitations of the Maxwell theory are discussed. The Weber theory, in addition to predicting all of the usual electrodynamic results, predicts the following crucial results for slowly varying effects (where Maxwell theory fails): 1) the force on Ampere's bridge in agreement with the measurements of Moyssides and Pappas, 2) the tension required to rupture current carrying wires as observed by Graneau, 3) the force to drive the Graneau-Hering submarine, 4) the force to drive the mercury in Hering's pump, and 5) the force to drive the oscillations in a current carrying mercury wedge as observed by Phipps.

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.

Turbidity Currents With Equilibrium Basal Driving Layers: A Mechanism for Long Runout

NASA Astrophysics Data System (ADS)

Luchi, R.; Balachandar, S.; Seminara, G.; Parker, G.

2018-02-01

Turbidity currents run out over 100 km in lakes and reservoirs, and over 1,000 km in the ocean. They do so without dissipating themselves via excess entrainment of ambient water. Existing layer-averaged formulations cannot capture this. We use a numerical model to describe the temporal evolution of a turbidity current toward steady state under condition of zero net sediment flux at the bed. The flow self-partitions itself into two layers. The lower "driving layer" approaches an invariant flow thickness, velocity profile, and suspended sediment concentration profile that sequesters nearly all of the suspended sediment. This layer can continue indefinitely at steady state over a constant bed slope. The upper "driven layer" contains a small fraction of the suspended sediment. The devolution of the flow into these two layers likely allows the driving layer to run out long distances.

Whistlers, helicons, and lower hybrid waves: The physics of radio frequency wave propagation and absorption for current drive via Landau damping

DOE PAGES

Pinsker, Robert I.

2015-09-24

This introductory-level tutorial article describes the application of plasma waves in the lower hybrid range of frequencies for current drive in tokamaks. Wave damping mechanisms in a nearly collisionless hot magnetized plasma are briefly described, and the connections between the properties of the damping mechanisms and the optimal choices of wave properties (mode, frequency, wavelength) are explored. The two wave modes available for current drive in the lower hybrid range of frequencies (LHRF) are described and compared. The terms applied to these waves in different applications of plasma physics are elucidated. Here, the character of the ray paths of thesemore » waves in the LHRF is illustrated in slab and toroidal geometries. An upcoming experiment on one of these two wave modes, the “helicon” or “whistler”, to be carried out on the DIII-D tokamak, is described.« less

Recent experimental results of KSTAR RF heating and current drive

NASA Astrophysics Data System (ADS)

Wang, S. J.; Kim, J.; Jeong, J. H.; Kim, H. J.; Joung, M.; Bae, Y. S.; Kwak, J. G.

2015-12-01

The overview of KSTAR activities on ICRH, LHCD and ECH/CD including the last experimental results and future plan aiming for long-pulse high-beta plasma will be presented. Recently we achieved reasonable coupling of ICRF power to H-mode plasma through several efforts to increase system reliability. Power balance will be discussed on this experiment. LHCD is still struggling in the low power regime. Review of antenna spectrum for the higher coupling in H-mode plasma will be tried. ECH/CD provides 41 sec, 0.8 MW of heating power to support high-performance long-pulse discharge. Also, 170 GHz ECH system is integrated with the Plasma Control System (PCS) for the feedback controlling of NTM. Status and plan of ECH/CD will be discussed. Finally, helicon current drive is being prepared for the next stage of KSTAR operation. The hardware preparation and the calculation results of helicon current drive in KSTAR plasma will be discussed.

Redundant drive current imbalance problem of the Automatic Radiator Inspection Device (ARID)

NASA Technical Reports Server (NTRS)

Latino, Carl D.

1992-01-01

The Automatic Radiator Inspection Device (ARID) is a 4 Degree of Freedom (DOF) robot with redundant drive motors at each joint. The device is intended to automate the labor intensive task of space shuttle radiator inspection. For safety and redundancy, each joint is driven by two independent motor systems. Motors driving the same joint, however, draw vastly different currents. The concern was that the robot joints could be subjected to undue stress. It was the objective of this summer's project to determine the cause of this current imbalance. In addition it was to determine, in a quantitative manner, what was the cause, how serious the problem was in terms of damage or undue wear to the robot and find solutions if possible. It was concluded that most problems could be resolved with a better motor control design. This document discusses problems encountered and possible solutions.

Cannabis effects on driving skills.

PubMed

Hartman, Rebecca L; Huestis, Marilyn A

2013-03-01

Cannabis is the most prevalent illicit drug identified in impaired drivers. The effects of cannabis on driving continue to be debated, making prosecution and legislation difficult. Historically, delays in sample collection, evaluating the inactive Δ(9)-tetrahydrocannabinol (THC) metabolite 11-nor-9-carboxy-THC, and polydrug use have complicated epidemiologic evaluations of driver impairment after cannabis use. We review and evaluate the current literature on cannabis' effects on driving, highlighting the epidemiologic and experimental data. Epidemiologic data show that the risk of involvement in a motor vehicle accident (MVA) increases approximately 2-fold after cannabis smoking. The adjusted risk of driver culpability also increases substantially, particularly with increased blood THC concentrations. Studies that have used urine as the biological matrix have not shown an association between cannabis and crash risk. Experimental data show that drivers attempt to compensate by driving more slowly after smoking cannabis, but control deteriorates with increasing task complexity. Cannabis smoking increases lane weaving and impaired cognitive function. Critical-tracking tests, reaction times, divided-attention tasks, and lane-position variability all show cannabis-induced impairment. Despite purported tolerance in frequent smokers, complex tasks still show impairment. Combining cannabis with alcohol enhances impairment, especially lane weaving. Differences in study designs frequently account for inconsistencies in results between studies. Participant-selection bias and confounding factors attenuate ostensible cannabis effects, but the association with MVA often retains significance. Evidence suggests recent smoking and/or blood THC concentrations 2-5 ng/mL are associated with substantial driving impairment, particularly in occasional smokers. Future cannabis-and-driving research should emphasize challenging tasks, such as divided attention, and include occasional and chronic daily cannabis smokers.

--No Title--

Science.gov Websites

when his car went into a ravine due to high waters. 8/8/2013 MO Jane McDonald 69 F Road Driving Brush Road Driving Appears victim tried to drive through high water on a road, but stalled. Got out to try the flooded area of a street when his car was swept away by the forceful current off of the road and

Ultra-High Intensity Magnetic Field Generation in Dense Plasma

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

Fisch, Nathaniel J.

2014-01-08

The main objective of this grant proposal was to explore the efficient generation of intense currents. Whereas the efficient generation of electric current in low-­energy-­density plasma has occupied the attention of the magnetic fusion community for several decades, scant attention has been paid to carrying over to high-­energy-­density plasma the ideas for steady-­state current drive developed for low-­energy-­density plasma, or, for that matter, to inventing new methodologies for generating electric current in high-­energy-­density plasma. What we proposed to do was to identify new mechanisms to accomplish current generation, and to assess the operation, physics, and engineering basis of new formsmore » of current drive in regimes appropriate for new fusion concepts.« less

Changing drivers' minds: the evaluation of an advanced driver coaching system.

PubMed

Stanton, N A; Walker, G H; Young, M S; Kazi, T; Salmon, P M

2007-08-01

This paper reports on the study of an advanced driver coaching system. The study distinguishes between different types of post-licensure programmes in order to explore a system based on a model of identifying and responding to hazards, called 'information, position, speed, gear and acceleration' (IPSGA). Previous literature has been sceptical about the benefits of advanced driver education; thus, the current study was designed to control for the effects of coaching drivers in the 'IPSGA' system (the treatment group) against the effects of being accompanied (control group 1), as well as the mere effects of time (control group 2). Measures were taken before the driver coaching began (as a baseline measure) and again after 8 weeks (to see if any changes had occurred). These measures included driver knowledge via a post-drive interview, observations of driving skill and driver attitude using a locus of control scale. The results suggest that advanced driver coaching using the IPSGA system had a beneficial effect on all of these measures. Drivers in the coaching condition improved their situation awareness, driving skills and reduced attributions of external locus of control. The study lends support to the case for one-to-one individualized driver coaching using a systematic model of driving.

Timely precipitation drives cover crop outcomes

USDA-ARS?s Scientific Manuscript database

Cover crops can expand ecosystem services, though sound management recommendations for their use within semi-arid cropping systems is currently constrained by a lack of information. This study was conducted to determine agroecosystem responses to late-summer seeded cover crops under no-till managem...

The Latent Structure of Dietary Restraint, Body Dissatisfaction, and Drive for Thinness: A Series of Taxometric Analyses

ERIC Educational Resources Information Center

Holm-Denoma, Jill M.; Richey, J. Anthony; Joiner, Thomas E., Jr.

2010-01-01

Although the latent structure of various eating disorders has been explored in previous studies, no published studies have examined the latent structure of theoretically relevant variables that have been shown to cut across eating disorder diagnoses. The current study examined 3 such variables (dietary restraint, body dissatisfaction, and drive…

Current Sensor Fault Reconstruction for PMSM Drives

PubMed Central

Huang, Gang; Luo, Yi-Ping; Zhang, Chang-Fan; He, Jing; Huang, Yi-Shan

2016-01-01

This paper deals with a current sensor fault reconstruction algorithm for the torque closed-loop drive system of an interior PMSM. First, sensor faults are equated to actuator ones by a new introduced state variable. Then, in αβ coordinates, based on the motor model with active flux linkage, a current observer is constructed with a specific sliding mode equivalent control methodology to eliminate the effects of unknown disturbances, and the phase current sensor faults are reconstructed by means of an adaptive method. Finally, an αβ axis current fault processing module is designed based on the reconstructed value. The feasibility and effectiveness of the proposed method are verified by simulation and experimental tests on the RT-LAB platform. PMID:26840317

Exact Large-Deviation Statistics for a Nonequilibrium Quantum Spin Chain

NASA Astrophysics Data System (ADS)

Žnidarič, Marko

2014-01-01

We consider a one-dimensional XX spin chain in a nonequilibrium setting with a Lindblad-type boundary driving. By calculating large-deviation rate function in the thermodynamic limit, a generalization of free energy to a nonequilibrium setting, we obtain a complete distribution of current, including closed expressions for lower-order cumulants. We also identify two phase-transition-like behaviors in either the thermodynamic limit, at which the current probability distribution becomes discontinuous, or at maximal driving, when the range of possible current values changes discontinuously. In the thermodynamic limit the current has a finite upper and lower bound. We also explicitly confirm nonequilibrium fluctuation relation and show that the current distribution is the same under mapping of the coupling strength Γ→1/Γ.

Recent progress of RF-dominated experiments on EAST

NASA Astrophysics Data System (ADS)

Liu, F. K.; Zhao, Y. P.; Shan, J. F.; Zhang, X. J.; Ding, B. J.; Wang, X. J.; Wang, M.; Xu, H. D.; Qin, C. M.; Li, M. H.; Gong, X. Z.; Hu, L. Q.; Wan, B. N.; Song, Y. T.; Li, J. G.

2017-10-01

The research of EAST program is mostly focused on the development of high performance steady state scenario with ITER-like poloidal configuration and RF-dominated heating schemes. With the enhanced ITER-relevant auxiliary heating and current drive systems, the plasma profile control by coupling/integration of various combinations has been investigated, including lower hybrid current drive (LHCD), electron cyclotron resonance heating (ECRH) and ion cyclotron resonance heating (ICRH). The 12 MW ICRH system has been installed on EAST. Heating and confinement studies using the Hydrogen Minority Heating scheme have been investigated. One of the importance challenges for EAST is coupling higher power into the core plasma, experiments including changing plasma position, electron density, local gas puffing and antenna phasing scanning were performed to improve ICRF coupling efficiency on EAST. Results show that local gas injection and reducing the k|| can improve the coupling efficiency directly. By means of the 4.6 GHz and 2.45 GHz LHCD systems, H-mode can be obtained and sustained at relatively high density, even up to ne ˜ 4.5 × 1019 m-3, where a current drive effect is still observed. Meanwhile, effect of source frequency (2.45GHz and 4.6GHz) on LHCD characteristic has been studied on EAST, showing that higher frequency improves penetration of the coupled LH (lower hybrid) power into the plasma core and leads to a better effect on plasma characteristics. Studies demonstrate the role of parasitic effects of edge plasma in LHCD and the mitigation by increasing source frequency. Experiments of effect of LH spectrum and plasma density on plasma characteristics are performed, suggesting the possibility of plasma control for high performance. The development of a 4MW ECRH system is in progress for the purpose of plasma heating and MHD control. The built ECRH system with 1MW source power has been successfully put into use on EAST in 2015. H-mode discharges with L-H transition triggered by ECRH injection were obtained and its effects on the electron temperature, particle confinement and the core MHD stabilities were observed. By further exploring and optimizing the RF combination for the sole RF heating and current drive regime, fully non-inductive H-mode discharges with Vloop˜0V has progressed steadily in the 2016 campaign. The overview of the significant progress of RF dominated experiments is presented in this paper.

The methodological quality of three foundational law enforcement drug influence evaluation validation studies

PubMed Central

2013-01-01

Background A Drug Influence Evaluation (DIE) is a formal assessment of an impaired driving suspect, performed by a trained law enforcement officer who uses circumstantial facts, questioning, searching, and a physical exam to form an unstandardized opinion as to whether a suspect’s driving was impaired by drugs. This paper first identifies the scientific studies commonly cited in American criminal trials as evidence of DIE accuracy, and second, uses the QUADAS tool to investigate whether the methodologies used by these studies allow them to correctly quantify the diagnostic accuracy of the DIEs currently administered by US law enforcement. Results Three studies were selected for analysis. For each study, the QUADAS tool identified biases that distorted reported accuracies. The studies were subject to spectrum bias, selection bias, misclassification bias, verification bias, differential verification bias, incorporation bias, and review bias. The studies quantified DIE performance with prevalence-dependent accuracy statistics that are internally but not externally valid. Conclusion The accuracies reported by these studies do not quantify the accuracy of the DIE process now used by US law enforcement. These studies do not validate current DIE practice. PMID:24188398

Update LADOTD policy on pile driving vibration management.

DOT National Transportation Integrated Search

2012-02-01

The main objective of this project was to update the current Louisiana Department of Transportation and Development (LADOTD) policy on pile driving vibration risk management with a focus on how to determine an appropriate vibration monitoring area. T...

Useful field of view in simulated driving: Reaction times and eye movements of drivers

PubMed Central

Seya, Yasuhiro; Nakayasu, Hidetoshi; Yagi, Tadasu

2013-01-01

To examine the spatial distribution of a useful field of view (UFOV) in driving, reaction times (RTs) and eye movements were measured in simulated driving. In the experiment, a normal or mirror-reversed letter “E” was presented on driving images with different eccentricities and directions from the current gaze position. The results showed significantly slower RTs in the upper and upper left directions than in the other directions. The RTs were significantly slower in the left directions than in the right directions. These results suggest that the UFOV in driving may be asymmetrical among the meridians in the visual field. PMID:24349688

In Situ Mortality Experiments with Juvenile Sea Bass (Dicentrarchus labrax) in Relation to Impulsive Sound Levels Caused by Pile Driving of Windmill Foundations

PubMed Central

Debusschere, Elisabeth; De Coensel, Bert; Bajek, Aline; Botteldooren, Dick; Hostens, Kris; Vanaverbeke, Jan; Vandendriessche, Sofie; Van Ginderdeuren, Karl; Vincx, Magda; Degraer, Steven

2014-01-01

Impact assessments of offshore wind farm installations and operations on the marine fauna are performed in many countries. Yet, only limited quantitative data on the physiological impact of impulsive sounds on (juvenile) fishes during pile driving of offshore wind farm foundations are available. Our current knowledge on fish injury and mortality due to pile driving is mainly based on laboratory experiments, in which high-intensity pile driving sounds are generated inside acoustic chambers. To validate these lab results, an in situ field experiment was carried out on board of a pile driving vessel. Juvenile European sea bass (Dicentrarchus labrax) of 68 and 115 days post hatching were exposed to pile-driving sounds as close as 45 m from the actual pile driving activity. Fish were exposed to strikes with a sound exposure level between 181 and 188 dB re 1 µPa2.s. The number of strikes ranged from 1739 to 3067, resulting in a cumulative sound exposure level between 215 and 222 dB re 1 µPa2.s. Control treatments consisted of fish not exposed to pile driving sounds. No differences in immediate mortality were found between exposed and control fish groups. Also no differences were noted in the delayed mortality up to 14 days after exposure between both groups. Our in situ experiments largely confirm the mortality results of the lab experiments found in other studies. PMID:25275508

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.

Emotion Perception or Social Cognitive Complexity: What Drives Face Processing Deficits in Autism Spectrum Disorder?

ERIC Educational Resources Information Center

Walsh, Jennifer A.; Creighton, Sarah E.; Rutherford, M. D.

2016-01-01

Some, but not all, relevant studies have revealed face processing deficits among those with autism spectrum disorder (ASD). In particular, deficits are revealed in face processing tasks that involve emotion perception. The current study examined whether either deficits in processing emotional expression or deficits in processing social cognitive…

International Tests and the U.S. Educational Reforms: Can Success Be Replicated?

ERIC Educational Resources Information Center

Turgut, Guliz

2013-01-01

The ranking of the United States in major international tests such as the Progress in International Reading Literacy Study (PIRLS), Trends in International Mathematics and Science Study (TIMSS), and Program for International Student Assessment (PISA) is used as the driving force and rationale for the current educational reforms in the United…

The role of cognitive and visual abilities as predictors in the Multifactorial Model of Driving Safety.

PubMed

Anstey, Kaarin J; Horswill, Mark S; Wood, Joanne M; Hatherly, Christopher

2012-03-01

The current study evaluated part of the Multifactorial Model of Driving Safety to elucidate the relative importance of cognitive function and a limited range of standard measures of visual function in relation to the Capacity to Drive Safely. Capacity to Drive Safely was operationalized using three validated screening measures for older drivers. These included an adaptation of the well validated Useful Field of View (UFOV) and two newer measures, namely a Hazard Perception Test (HPT), and a Hazard Change Detection Task (HCDT). Community dwelling drivers (n=297) aged 65-96 were assessed using a battery of measures of cognitive and visual function. Factor analysis of these predictor variables yielded factors including Executive/Speed, Vision (measured by visual acuity and contrast sensitivity), Spatial, Visual Closure, and Working Memory. Cognitive and Vision factors explained 83-95% of age-related variance in the Capacity to Drive Safely. Spatial and Working Memory were associated with UFOV, HPT and HCDT, Executive/Speed was associated with UFOV and HCDT and Vision was associated with HPT. The Capacity to Drive Safely declines with chronological age, and this decline is associated with age-related declines in several higher order cognitive abilities involving manipulation and storage of visuospatial information under speeded conditions. There are also age-independent effects of cognitive function and vision that determine driving safety. Copyright © 2011 Elsevier Ltd. All rights reserved.

Epilepsy and driving: considerations on how eligibility should be decided.

PubMed

Lossius, R; Kinge, E; Nakken, K O

2010-01-01

Although few neurologists are formally trained in traffic medicine, they are frequently asked to assess whether a patient is medically fit to drive. For patients with epilepsy, the physician must assess the risk of the patient having a seizure while driving, and decide what is an acceptable risk. The legislation on this subject is aiming at finding a reasonable balance between two important considerations: public safety and a patient's individual need to drive. For the neurologist to explain and put into practice the legislation may be a demanding task and a challenge to the doctor-patient alliance. The decision on driving capability should be tailored to the individual patient and based on careful evaluation and informed judgement. In Norway, to qualify for a driver's license, a seizure-free interval of at least 12 months is currently required for group 1 drivers (passenger cars), whereas group 2 drivers (heavy motor vehicles, commercial driving) must have been seizure-free for at least 10 years and not have experienced epileptic seizures from the age of 18 years. Norwegian physicians are obliged to report patients with seizures to driving authorities, although this is an unpopular rule. In reviewing the available literature, it is apparent that despite there being relatively few sound studies, the risks of car accidents among persons with epilepsy may previously have been overestimated.

Keep Your Scanners Peeled: Gaze Behavior as a Measure of Automation Trust During Highly Automated Driving.

PubMed

Hergeth, Sebastian; Lorenz, Lutz; Vilimek, Roman; Krems, Josef F

2016-05-01

The feasibility of measuring drivers' automation trust via gaze behavior during highly automated driving was assessed with eye tracking and validated with self-reported automation trust in a driving simulator study. Earlier research from other domains indicates that drivers' automation trust might be inferred from gaze behavior, such as monitoring frequency. The gaze behavior and self-reported automation trust of 35 participants attending to a visually demanding non-driving-related task (NDRT) during highly automated driving was evaluated. The relationship between dispositional, situational, and learned automation trust with gaze behavior was compared. Overall, there was a consistent relationship between drivers' automation trust and gaze behavior. Participants reporting higher automation trust tended to monitor the automation less frequently. Further analyses revealed that higher automation trust was associated with lower monitoring frequency of the automation during NDRTs, and an increase in trust over the experimental session was connected with a decrease in monitoring frequency. We suggest that (a) the current results indicate a negative relationship between drivers' self-reported automation trust and monitoring frequency, (b) gaze behavior provides a more direct measure of automation trust than other behavioral measures, and (c) with further refinement, drivers' automation trust during highly automated driving might be inferred from gaze behavior. Potential applications of this research include the estimation of drivers' automation trust and reliance during highly automated driving. © 2016, Human Factors and Ergonomics Society.

Topological Frequency Conversion in Strongly Driven Quantum Systems

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

Martin, Ivar; Refael, Gil; Halperin, Bertrand

When a physical system is subjected to a strong external multi-frequency drive, its dynamics can be conveniently represented in the multi-dimensional Floquet lattice. The number of the Floquet lattice dimensions equals the number of irrationally-related drive frequencies, and the evolution occurs in response to a built-in effective \\electric" field, whose components are proportional to the corresponding drive frequencies. The mapping allows to engineer and study temporal analogs of many real-space phenomena. Here we focus on the specifc example of a two-level system under two-frequency drive that induces topologically nontrivial band structure in the 2D Floquet space. The observable consequence ofmore » such construction is quantized pumping of energy between the sources with frequencies w 1 and w 2. Finally, when the system is initialized into a Floquet band with the Chern number C, the pumping occurs at the rate P 12 = – P 21 = ( C/2π)hw 1w 2, an exact counterpart of the transverse current in a conventional topological insulator.« less

Topological Frequency Conversion in Strongly Driven Quantum Systems

DOE PAGES

Martin, Ivar; Refael, Gil; Halperin, Bertrand

2017-10-16

When a physical system is subjected to a strong external multi-frequency drive, its dynamics can be conveniently represented in the multi-dimensional Floquet lattice. The number of the Floquet lattice dimensions equals the number of irrationally-related drive frequencies, and the evolution occurs in response to a built-in effective \\electric" field, whose components are proportional to the corresponding drive frequencies. The mapping allows to engineer and study temporal analogs of many real-space phenomena. Here we focus on the specifc example of a two-level system under two-frequency drive that induces topologically nontrivial band structure in the 2D Floquet space. The observable consequence ofmore » such construction is quantized pumping of energy between the sources with frequencies w 1 and w 2. Finally, when the system is initialized into a Floquet band with the Chern number C, the pumping occurs at the rate P 12 = – P 21 = ( C/2π)hw 1w 2, an exact counterpart of the transverse current in a conventional topological insulator.« less

Recovery of Barotrauma Injuries Resulting from Exposure to Pile Driving Sound in Two Sizes of Hybrid Striped Bass

PubMed Central

Matthews, Frazer; Carlson, Thomas J.; Popper, Arthur N.

2013-01-01

The effects of loud sounds on fishes, such as those produced during impulsive pile driving, are an increasing concern in the management of aquatic ecosystems. However, very little is known about such effects. Accordingly, a High Intensity Controlled Impedance Fluid Filled wave Tube (HICI-FT) was used to investigate the effects of sounds produced by impulsive pile driving on two size groups of hybrid striped bass (white bass Morone chrysops x striped bass Morone saxatilis ). The larger striped bass (mean size 17.2 g) had more severe injuries, as well as more total injuries, than the smaller fish (mean size 1.3 g). However, fish in each size group recovered from most injuries within 10 days of exposure. A comparison with different species from previously published studies show that current results support the observation that fishes with physoclistous swim bladders are more susceptible to injury from impulsive pile driving than are fishes with physostomous swim bladders. PMID:24040089

Experiments on Helicon Excitation and Off-Axis Current Drive on DIII-D: Status and Plans

NASA Astrophysics Data System (ADS)

Pinsker, R. I.; Prater, R.; Moeller, C. P.; Degrassie, J. S.; Tooker, J. F.; Anderson, J. P.; Torreblanca, H.; Hansink, M.; Nagy, A.; Porkolab, M.

2015-11-01

Fast waves in the LHRF, also called ``whistlers'' or ``helicons,'' will be studied in experiments on the DIII-D tokamak beginning in autumn 2015. In the first stage, a 12-element traveling wave antenna (``comb-line'') is installed in the DIII-D vessel for operation at very low power (~ 0.1 kW) at 476 MHz, with a well-defined launched n| | spectrum peaked at 3.0. The goals of the low-power experiment include: (1) determining the efficiency with which the desired fast waves can be excited under a variety of plasma conditions in discharges relevant to the subsequent high-power current drive experiments and (2) proving that the radial and poloidal location at which the antenna will be mounted does not cause deleterious effects in the DIII-D discharges with high neutral beam power, and that the antenna is not damaged by fast ion losses, etc. Plans for 1 MW-level experiments with a single klystron beginning in FY17 are discussed. In addition to demonstrating off-axis current drive at an efficiency of ~ 60 kA/MW in high-performance plasmas, these experiments will explore non-linear aspects of wave excitation, propagation and absorption such as ponderomotive effects and parametric decay instabilities. Supported by US DOE DE-FC02-04ER54698, DE-AC02-09CH11466 and DE-FG02-94ER54084.

An Examination of Different Motivational Orientations That Drive Graduate Students to Continue/Complete Their Education in the U.S.

ERIC Educational Resources Information Center

Karayigit, Cebrail

2017-01-01

Different types and levels of motivation can play an important role for graduate students to continue their studies. The current research study was one of the few studies that examined if domestic and international graduate students differ on their level of different motivational orientations to continue their education. This study employs a…

Particle pinch with fully noninductive lower hybrid current drive in Tore Supra.

PubMed

Hoang, G T; Bourdelle, C; Pégourié, B; Schunke, B; Artaud, J F; Bucalossi, J; Clairet, F; Fenzi-Bonizec, C; Garbet, X; Gil, C; Guirlet, R; Imbeaux, F; Lasalle, J; Loarer, T; Lowry, C; Travère, J M; Tsitrone, E

2003-04-18

Recently, plasmas exceeding 4 min have been obtained with lower hybrid current drive (LHCD) in Tore Supra. These LHCD plasmas extend for over 80 times the resistive current diffusion time with zero loop voltage. Under such unique conditions the neoclassical particle pinch driven by the toroidal electric field vanishes. Nevertheless, the density profile remains peaked for more than 4 min. For the first time, the existence of an inward particle pinch in steady-state plasma without toroidal electric field, much larger than the value predicted by the collisional neoclassical theory, is experimentally demonstrated.

Conceptual Design for CLIC Gun Pulser

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

Tang, Tao

The Compact Linear Collider (CLIC) is a proposed future electron-positron collider, designed to perform collisions at energies from 0.5 to 5 TeV, with a nominal design optimized for 3 TeV (Dannheim, 2012). The Drive Beam Accelerator consists of a thermionic DC gun, bunching section and an accelerating section. The thermionic gun needs deliver a long (~143us) pulse of current into the buncher. A pulser is needed to drive grid of the gun to generate a stable current output. This report explores the requirements of the gun pulser and potential solutions to regulate grid current.

Vision and Driving

PubMed Central

Owsley, Cynthia; McGwin, Gerald

2010-01-01

Driving is the primary means of personal travel in many countries and is relies heavily on vision for its successful execution. Research over the past few decades has addressed the role of vision in driver safety (motor vehicle collision involvement) and in driver performance (both on-road and using interactive simulators in the laboratory). Here we critically review what is currently known about the role of various aspects of visual function in driving. We also discuss translational research issues on vision screening for licensure and re-licensure and rehabilitation of visually impaired persons who want to drive. PMID:20580907

The impact of immediate or delayed feedback on driving behaviour in a simulated Pay-As-You-Drive system.

PubMed

Dijksterhuis, Chris; Lewis-Evans, Ben; Jelijs, Bart; de Waard, Dick; Brookhuis, Karel; Tucha, Oliver

2015-02-01

Pay-As-You-Drive (PAYD) insurance links an individual's driving behaviour to the insurance fee that they pay, making car insurance more actuarially accurate. The best known PAYD insurance format is purely mileage based and is estimated to reduce accidents by about 15% (Litman, 2011). However, these benefits could be further enhanced by incorporating a wider range of driving behaviours, such as lateral and longitudinal accelerations and speeding behaviour, thereby stimulating not only a safe but also an eco-friendly driving style. Currently, feedback on rewards and driver behaviour is mostly provided through a web-based interface, which is presented temporally separated from driving. However, providing immediate feedback within the vehicle itself could elicit more effect. To investigate this hypothesis, two groups of 20 participants drove with a behavioural based PAYD system in a driving simulator and were provided with either delayed feedback through a website, or immediate feedback through an in-car interface, allowing them to earn up to €6 extra. To be clear, every participant in the web group did actually view their feedback during the one week between sessions. Results indicate clear driving behaviour improvements for both PAYD groups as compared to baseline rides and an equal sized control group. After both PAYD groups had received feedback, the initial advantage of the in-car group was reduced substantially. Taken together with usability ratings and driving behaviours in specific situations these results show a moderate advantage of using immediate in-car feedback. However, the study also showed that under conditions of feedback certainty, the effectiveness of delayed feedback approaches that of immediate feedback as compared to a naïve control group. Copyright © 2014 Elsevier Ltd. All rights reserved.

Compact antenna for two-dimensional beam scan in the JT-60U electron cyclotron heating/current drive system

NASA Astrophysics Data System (ADS)

Moriyama, S.; Kajiwara, K.; Takahashi, K.; Kasugai, A.; Seki, M.; Ikeda, Y.; Fujii, T.

2005-11-01

A compact antenna system was designed and fabricated to enable millimeter-wave beam scanning in the toroidal and poloidal directions of the JT-60U tokamak for electron cyclotron heating (ECH) and electron cyclotron current drive (ECCD) experiments. The antenna consists of a fast movable flat mirror mounted on the tokamak vacuum vessel and a rotary focusing mirror attached at the end of the waveguide that is supported from outside the vacuum vessel. This separate support concept enables a compact structure inside a shallow port (0.68×0.54×0.2m) that is shared with a subport for an independent diagnostic system. During a plasma shot, the flat mirror is driven by a servomotor with a 3-m-long drive shaft to reduce the influence of the high magnetic field on the motor. The focusing mirror is rotated by a simple mechanism utilizing a push rod and an air cylinder. The antenna has been operated reliably for 3 years after a small improvement to the rotary drive mechanism. It has made significant contributions to ECH and ECCD experiments, especially the current profile control in JT-60U.

Alpha effect of Alfv{acute e}n waves and current drive in reversed-field pinches

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

Litwin, C.; Prager, S.C.

Circularly polarized Alfv{acute e}n waves give rise to an {alpha}-dynamo effect that can be exploited to drive parallel current. In a {open_quotes}laminar{close_quotes} magnetic the effect is weak and does not give rise to significant currents for realistic parameters (e.g., in tokamaks). However, in reversed-field pinches (RFPs) in which magnetic field in the plasma core is stochastic, a significant enhancement of the {alpha} effect occurs. Estimates of this effect show that it may be a realistic method of current generation in the present-day RFP experiments and possibly also in future RFP-based fusion reactors. {copyright} {ital 1998 American Institute of Physics.}

A guide for statewide impaired-driving task forces.

DOT National Transportation Integrated Search

2009-09-01

The purpose of the guide is to assist State officials and other stakeholders who are interested in establishing an : Impaired-Driving Statewide Task Force or who are exploring ways to improve their current Task Force. The guide : addresses issues suc...

Evaluation of the New Mexico ignition interlock program : traffic tech.

DOT National Transportation Integrated Search

2010-11-01

Impaired driving is a major factor in vehicle crashes and traffic : fatalities. The use of ignition interlocks is growing as a : countermeasure to combat the high rate of offender recidivism : for driving while intoxicated (DWI). New Mexico currently...

German taxi drivers' experiences and expressions of driving anger: Are the driving anger scale and the driving anger expression inventory valid measures?

PubMed

Brandenburg, Stefan; Oehl, Michael; Seigies, Kristin

2017-11-17

The objective of this article was 2-fold: firstly, we wanted to examine whether the original Driving Anger Scale (DAS) and the original Driving Anger Expression Inventory (DAX) apply to German professional taxi drivers because these scales have previously been given to professional and particularly to nonprofessional drivers in different countries. Secondly, we wanted to examine possible differences in driving anger experience and expression between professional German taxi drivers and nonprofessional German drivers. We applied German versions of the DAS, the DAX, and the State-Trait Anger Expression Inventory (STAXI) to a sample of 138 professional German taxi drivers. We then compared their ratings to the ratings of a sample of 1,136 nonprofessional German drivers (Oehl and Brandenburg n.d. ). Regarding our first objective, confirmatory factor analysis shows that the model fit of the DAS is better for nonprofessional drivers than for professional drivers. The DAX applies neither to professional nor to nonprofessional German drivers properly. Consequently, we suggest modified shorter versions of both scales for professional drivers. The STAXI applies to both professional and nonprofessional drivers. With respect to our second objective, we show that professional drivers experience significantly less driving anger than nonprofessional drivers, but they express more driving anger. We conclude that the STAXI can be applied to professional German taxi drivers. In contrast, for the DAS and the DAX we found particular shorter versions for professional taxi drivers. Especially for the DAX, most statements were too strong for German drivers to agree to. They do not show behaviors related to driving anger expression as they are described in the DAX. These problems with the original American DAX items are in line with several other studies in different countries. Future investigations should examine whether (professional) drivers from further countries express their anger as proposed by the DAX. In addition, professional drivers experience less driving anger (DAS) and less general trait anger (STAXI) than nonprofessional drivers, but they report more driving anger expression (DAX) and more current general state anger (STAXI). Subsequent studies should therefore focus on different types of anger within the group of professional drivers.

A poloidal section neutron camera for MAST upgrade

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

Sangaroon, S.; Weiszflog, M.; Cecconello, M.

2014-08-21

The Mega Ampere Spherical Tokamak Upgrade (MAST Upgrade) is intended as a demonstration of the physics viability of the Spherical Tokamak (ST) concept and as a platform for contributing to ITER/DEMO physics. Concerning physics exploitation, MAST Upgrade plasma scenarios can contribute to the ITER Tokamak physics particularly in the field of fast particle behavior and current drive studies. At present, MAST is equipped with a prototype neutron camera (NC). On the basis of the experience and results from previous experimental campaigns using the NC, the conceptual design of a neutron camera upgrade (NC Upgrade) is being developed. As part ofmore » the MAST Upgrade, the NC Upgrade is considered a high priority diagnostic since it would allow studies in the field of fast ions and current drive with good temporal and spatial resolution. In this paper, we explore an optional design with the camera array viewing the poloidal section of the plasma from different directions.« less

Characterization and snubbing of a bidirectional MCT in a resonant ac link converter

NASA Technical Reports Server (NTRS)

Lee, Tony; Elbuluk, Malik E.; Zinger, Donald S.

1993-01-01

The MOS-Controlled Thyristor (MCT) is emerging as a powerful switch that combines the better characteristics of existing power devices. A study of switching stresses on an MCT switch under zero voltage resonant switching is presented. The MCT is used as a bidirectional switch in an ac/ac pulse density modulated inverter for induction motor drive. Current and voltage spikes are observed and analyzed with variations in the timing of the switching. Different snubber circuit configurations are under investigation to minimize the effect of these transients. The results will be extended to study and test the MCT switching in a medium power (5 hp) induction motor drive.

All solution processed organic thin film transistor-backplane with printing technology for electrophoretic display

USGS Publications Warehouse

Lee, Myung W.; Song, C.K.

2012-01-01

In this study, solution processes were developed for backplane using an organic thin film transistor (OTFT) as a driving device for an electrophoretic display (EPD) panel. The processes covered not only the key device of OTFTs but also interlayer and pixel electrodes. The various materials and printing processes were adopted to achieve the requirements of devices and functioning layers. The performance of OTFT of the backplane was sufficient to drive EPD sheet by producing a mobility of 0.12 cm2/v x sec and on/off current ratio of 10(5).

The least channel capacity for chaos synchronization.

PubMed

Wang, Mogei; Wang, Xingyuan; Liu, Zhenzhen; Zhang, Huaguang

2011-03-01

Recently researchers have found that a channel with capacity exceeding the Kolmogorov-Sinai entropy of the drive system (h(KS)) is theoretically necessary and sufficient to sustain the unidirectional synchronization to arbitrarily high precision. In this study, we use symbolic dynamics and the automaton reset sequence to distinguish the information that is required in identifying the current drive word and obtaining the synchronization. Then, we show that the least channel capacity that is sufficient to transmit the distinguished information and attain the synchronization of arbitrarily high precision is h(KS). Numerical simulations provide support for our conclusions.

Exploration of high harmonic fast wave heating on the National Spherical Torus Experiment

NASA Astrophysics Data System (ADS)

Wilson, J. R.; Bell, R. E.; Bernabei, S.; Bitter, M.; Bonoli, P.; Gates, D.; Hosea, J.; LeBlanc, B.; Mau, T. K.; Medley, S.; Menard, J.; Mueller, D.; Ono, M.; Phillips, C. K.; Pinsker, R. I.; Raman, R.; Rosenberg, A.; Ryan, P.; Sabbagh, S.; Stutman, D.; Swain, D.; Takase, Y.; Wilgen, J.

2003-05-01

High harmonic fast wave (HHFW) heating has been proposed as a particularly attractive means for plasma heating and current drive in the high beta plasmas that are achievable in spherical torus (ST) devices. The National Spherical Torus Experiment (NSTX) [M. Ono, S. M. Kaye, S. Neumeyer et al., in Proceedings of the 18th IEEE/NPSS Symposium on Fusion Engineering, Albuquerque, 1999 (IEEE, Piscataway, NJ, 1999), p. 53] is such a device. An rf heating system has been installed on the NSTX to explore the physics of HHFW heating, current drive via rf waves and for use as a tool to demonstrate the attractiveness of the ST concept as a fusion device. To date, experiments have demonstrated many of the theoretical predictions for HHFW. In particular, strong wave absorption on electrons over a wide range of plasma parameters and wave parallel phase velocities, wave acceleration of energetic ions, and indications of current drive for directed wave spectra have been observed. In addition HHFW heating has been used to explore the energy transport properties of NSTX plasmas, to create H-mode discharges with a large fraction of bootstrap current and to control the plasma current profile during the early stages of the discharge.

High-beta, steady-state hybrid scenario on DIII-D

DOE PAGES

Petty, C. C.; Kinsey, J. E.; Holcomb, C. T.; ...

2015-12-17

Here, the potential of the hybrid scenario (first developed as an advanced inductive scenario for high fluence) as a regime for high-beta, steady-state plasmas is demonstrated on the DIII-D tokamak. These experiments show that the beneficial characteristics of hybrids, namely safety factor ≥1 with low central magnetic shear, high stability limits and excellent confinement, are maintained when strong central current drive (electron cyclotron and neutral beam) is applied to increase the calculated non-inductive fraction to ≈100% (≈50% bootstrap current). The best discharges achieve normalized beta of 3.4, IPB98(y,2) confinement factor of 1.4, surface loop voltage of 0.01 V, and nearlymore » equal electron and ion temperatures at low collisionality. A zero-dimensional physics model shows that steady-state hybrid operation with Q fus ~ 5 is feasible in FDF and ITER. The advantage of the hybrid scenario as an Advanced Tokamak regime is that the external current drive can be deposited near the plasma axis where the efficiency is high; additionally, good alignment between the current drive and plasma current profiles is not necessary as the poloidal magnetic flux pumping self-organizes the current density profile in hybrids with an m/n=3/2 tearing mode.« less

Line length dependence of threshold current density and driving force in eutectic SnPb and SnAgCu solder electromigration

NASA Astrophysics Data System (ADS)

Yoon, Min-Seung; Ko, Min-Ku; Kim, Bit-Na; Kim, Byung-Joon; Park, Yong-Bae; Joo, Young-Chang

2008-04-01

The relationship between the threshold current density and the critical line length in eutectic SnPb and SnAgCu electromigrations were examined using solder lines with the various lengths ranging from 100to1000μm. When the electron wind-force was balanced by the back-stress gradient force, the net flux of electromigration is zero, at which the current density and line length are defined as the threshold current density and the critical length, respectively. It was found that in SnAgCu electromigration, the 1/L dependence on the threshold current density showed good agreement, whereas the threshold current densities of the eutectic SnPb deviated from the 1/L dependence. The balance between the electron wind-force and the back-stress gradient force was the main factor determining the threshold product of SnAgCu electromigration. On the other hand, in the case of eutectic SnPb, the chemical driving force is contributed as a back-flux force in addition to the back-stress gradient force. The existence of the chemical driving force was caused by the nonequilibrium Pb concentration inside the Pb-rich phases between the cathode and anode during the electromigration procedure.

Identifying Factors that Increase the Likelihood of Driving After Drinking among College Students

PubMed Central

LaBrie, Joseph W.; Kenney, Shannon R.; Mirza, Tehniat; Lac, Andrew

2012-01-01

Driving after drinking (DAD) is a serious public health concern found to be more common among college students than those of other age groups or same-aged non-college peers. The current study examined potential predictors of DAD among a dual-site sample of 3,753 (65% female, 58% Caucasian) college students. Results showed that 19.1% of respondents had driven after 3 or more drinks and 8.6% had driven after 5 or more drinks in the past three months. A logistic regression model showed that male status, fraternity or sorority affiliation, family history of alcohol abuse, medium or heavy drinking (as compared to light drinking), more approving self-attitudes towards DAD, and alcohol expectancies for sexual enhancement and risk/aggression, were independently associated with driving after drinking over and above covariates. These results extend the current understanding of this high risk drinking behavior in collegiate populations and provide implications for preventive strategies. Findings indicate that in addition to targeting at-risk subgroups, valuable directions for DAD-related interventions may include focusing on lowering both self-approval of DAD and alcohol-related expectancies, particularly those associated with risk/aggression and sexuality. PMID:21545868

VOC from Vehicular Evaporation Emissions: Status and Control Strategy.

PubMed

Liu, Huan; Man, Hanyang; Tschantz, Michael; Wu, Ye; He, Kebin; Hao, Jiming

2015-12-15

Vehicular evaporative emissions is an important source of volatile organic carbon (VOC), however, accurate estimation of emission amounts and scientific evaluation of control strategy for these emissions have been neglected outside of the United States. This study provides four kinds of basic emission factors: diurnal, hot soak, permeation, and refueling. Evaporative emissions from the Euro 4 vehicles (1.6 kg/year/car) are about four times those of U.S. vehicles (0.4 kg/year/car). Closing this emissions gap would have a larger impact than the progression from Euro 3 to Euro 6 tailpipe HC emission controls. Even in the first 24 h of parking, China's current reliance upon the European 24 h diurnal standard results in 508 g/vehicle/year emissions, higher than 32 g/vehicle/year from Tier 2 vehicles. The U.S. driving cycle matches Beijing real-world conditions much better on both typical trip length and average speed than current European driving cycles. At least two requirements should be added to the Chinese emissions standards: an onboard refueling vapor recovery to force the canister to be sized sufficiently large, and a 48-h evaporation test requirement to ensure that adequate purging occurs over a shorter drive sequence.

Risk factors of mobile phone use while driving in Queensland: Prevalence, attitudes, crash risk perception, and task-management strategies.

PubMed

Oviedo-Trespalacios, Oscar; King, Mark; Haque, Md Mazharul; Washington, Simon

2017-01-01

Distracted driving is one of the most significant human factor issues in transport safety. Mobile phone interactions while driving may involve a multitude of cognitive and physical resources that result in inferior driving performance and reduced safety margins. The current study investigates characteristics of usage, risk factors, compensatory strategies in use and characteristics of high-frequency offenders of mobile phone use while driving. A series of questions were administered to drivers in Queensland (Australia) using an on-line questionnaire. A total of 484 drivers (34.9% males and 49.8% aged 17-25) participated anonymously. At least one of every two motorists surveyed reported engaging in distracted driving. Drivers were unable to acknowledge the increased crash risk associated with answering and locating a ringing phone in contrast to other tasks such as texting/browsing. Attitudes towards mobile phone usage were more favourable for talking than texting or browsing. Lowering the driving speed and increasing the distance from the vehicle in front were the most popular task-management strategies for talking and texting/browsing while driving. On the other hand, keeping the mobile phone low (e.g. in the driver's lap or on the passenger seat) was the favourite strategy used by drivers to avoid police fines for both talking and texting/browsing. Logistic regression models were fitted to understand differences in risk factors for engaging in mobile phone conversations and browsing/texting while driving. For both tasks, exposure to driving, driving experience, driving history (offences and crashes), and attitudes were significant predictors. Future mobile phone prevention efforts would benefit from development of safe attitudes and increasing risk literacy. Enforcement of mobile phone distraction should be re-engineered, as the use of task-management strategies to evade police enforcement seems to dilute its effect on the prevention of this behaviour. Some countermeasures and suggestions were proposed in the design of public education campaigns and driver-mobile phone interaction.

Risk factors of mobile phone use while driving in Queensland: Prevalence, attitudes, crash risk perception, and task-management strategies

PubMed Central

King, Mark; Haque, Md. Mazharul; Washington, Simon

2017-01-01

Distracted driving is one of the most significant human factor issues in transport safety. Mobile phone interactions while driving may involve a multitude of cognitive and physical resources that result in inferior driving performance and reduced safety margins. The current study investigates characteristics of usage, risk factors, compensatory strategies in use and characteristics of high-frequency offenders of mobile phone use while driving. A series of questions were administered to drivers in Queensland (Australia) using an on-line questionnaire. A total of 484 drivers (34.9% males and 49.8% aged 17–25) participated anonymously. At least one of every two motorists surveyed reported engaging in distracted driving. Drivers were unable to acknowledge the increased crash risk associated with answering and locating a ringing phone in contrast to other tasks such as texting/browsing. Attitudes towards mobile phone usage were more favourable for talking than texting or browsing. Lowering the driving speed and increasing the distance from the vehicle in front were the most popular task-management strategies for talking and texting/browsing while driving. On the other hand, keeping the mobile phone low (e.g. in the driver’s lap or on the passenger seat) was the favourite strategy used by drivers to avoid police fines for both talking and texting/browsing. Logistic regression models were fitted to understand differences in risk factors for engaging in mobile phone conversations and browsing/texting while driving. For both tasks, exposure to driving, driving experience, driving history (offences and crashes), and attitudes were significant predictors. Future mobile phone prevention efforts would benefit from development of safe attitudes and increasing risk literacy. Enforcement of mobile phone distraction should be re-engineered, as the use of task-management strategies to evade police enforcement seems to dilute its effect on the prevention of this behaviour. Some countermeasures and suggestions were proposed in the design of public education campaigns and driver-mobile phone interaction. PMID:28877200

Examining the influence of aggressive driving behavior on driver injury severity in traffic crashes.

PubMed

Paleti, Rajesh; Eluru, Naveen; Bhat, Chandra R

2010-11-01

In this paper, we capture the moderating effect of aggressive driving behavior while assessing the influence of a comprehensive set of variables on injury severity. In doing so, we are able to account for the indirect effects of variables on injury severity through their influence on aggressive driving behavior, as well as the direct effect of variables on injury severity. The methodology used in the paper to accommodate the moderating effect of aggressive driving behavior takes the form of two models--one for aggressive driving and another for injury severity. These are appropriately linked to obtain the indirect and direct effects of variables. The data for estimation is obtained from the National Motor Vehicle Crash Causation Study (NMVCCS). From an empirical standpoint, we consider a fine age categorization until 20 years of age when examining age effects on aggressive driving behavior and injury severity. There are several important results from the empirical analysis undertaken in the current paper based on post-crash data collection on aggressive behavior participation just prior to the crash and injury severity sustained in a crash. Young drivers (especially novice drivers between 16 and 17 years of age), drivers who are not wearing seat belt, under the influence of alcohol, not having a valid license, and driving a pick-up are found to be most likely to behave aggressively. Situational, vehicle, and roadway factors such as young drivers traveling with young passengers, young drivers driving an SUV or a pick-up truck, driving during the morning rush hour, and driving on roads with high speed limits are also found to trigger aggressive driving behavior. In terms of vehicle occupants, the safest situation from a driver injury standpoint is when there are two or more passengers in the vehicle, at least one of whom is above the age of 20 years. These and many other results are discussed, along with implications of the result for graduated driving licensing (GDL) programs. 2010 Elsevier Ltd. All rights reserved.

Quantization and fractional quantization of currents in periodically driven stochastic systems. I. Average currents

NASA Astrophysics Data System (ADS)

Chernyak, Vladimir Y.; Klein, John R.; Sinitsyn, Nikolai A.

2012-04-01

This article studies Markovian stochastic motion of a particle on a graph with finite number of nodes and periodically time-dependent transition rates that satisfy the detailed balance condition at any time. We show that under general conditions, the currents in the system on average become quantized or fractionally quantized for adiabatic driving at sufficiently low temperature. We develop the quantitative theory of this quantization and interpret it in terms of topological invariants. By implementing the celebrated Kirchhoff theorem we derive a general and explicit formula for the average generated current that plays a role of an efficient tool for treating the current quantization effects.

Fast-ion transport in qmin>2, high- β steady-state scenarios on DIII-D

DOE PAGES

Holcomb, C. T.; Heidbrink, W. W.; Ferron, J. R.; ...

2015-05-22

The results from experiments on DIII-D [J. L. Luxon, Fusion Sci. Technol. 48, 828 (2005)] aimed at developing high β steady-state operating scenarios with high-qminqmin confirm that fast-ion transport is a critical issue for advanced tokamak development using neutral beam injection current drive. In DIII-D, greater than 11 MW of neutral beam heating power is applied with the intent of maximizing β N and the noninductive current drive. However, in scenarios with q min>2 that target the typical range of q 95= 5–7 used in next-step steady-state reactor models, Alfvén eigenmodes cause greater fast-ion transport than classical models predict. Thismore » enhanced transport reduces the absorbed neutral beam heating power and current drive and limits the achievable β N. Conversely similar plasmas except with q min just above 1 have approximately classical fast-ion transport. Experiments that take q min>3 plasmas to higher β P with q 95= 11–12 for testing long pulse operation exhibit regimes of better than expected thermal confinement. Compared to the standard high-q min scenario, the high β P cases have shorter slowing-down time and lower ∇β fast, and this reduces the drive for Alfvénic modes, yielding nearly classical fast-ion transport, high values of normalized confinement, β N, and noninductive current fraction. These results suggest DIII-D might obtain better performance in lower-q 95, high-q min plasmas using broader neutral beam heating profiles and increased direct electron heating power to lower the drive for Alfvén eigenmodes.« less

Fast-ion transport in q{sub min}>2, high-β steady-state scenarios on DIII-D

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

Holcomb, C. T.; Heidbrink, W. W.; Collins, C.

2015-05-15

Results from experiments on DIII-D [J. L. Luxon, Fusion Sci. Technol. 48, 828 (2005)] aimed at developing high β steady-state operating scenarios with high-q{sub min} confirm that fast-ion transport is a critical issue for advanced tokamak development using neutral beam injection current drive. In DIII-D, greater than 11 MW of neutral beam heating power is applied with the intent of maximizing β{sub N} and the noninductive current drive. However, in scenarios with q{sub min}>2 that target the typical range of q{sub 95}= 5–7 used in next-step steady-state reactor models, Alfvén eigenmodes cause greater fast-ion transport than classical models predict. Thismore » enhanced transport reduces the absorbed neutral beam heating power and current drive and limits the achievable β{sub N}. In contrast, similar plasmas except with q{sub min} just above 1 have approximately classical fast-ion transport. Experiments that take q{sub min}>3 plasmas to higher β{sub P} with q{sub 95}= 11–12 for testing long pulse operation exhibit regimes of better than expected thermal confinement. Compared to the standard high-q{sub min} scenario, the high β{sub P} cases have shorter slowing-down time and lower ∇β{sub fast}, and this reduces the drive for Alfvénic modes, yielding nearly classical fast-ion transport, high values of normalized confinement, β{sub N}, and noninductive current fraction. These results suggest DIII-D might obtain better performance in lower-q{sub 95}, high-q{sub min} plasmas using broader neutral beam heating profiles and increased direct electron heating power to lower the drive for Alfvén eigenmodes.« less

ADX - Advanced Divertor and RF Tokamak Experiment

NASA Astrophysics Data System (ADS)

Greenwald, Martin; Labombard, Brian; Bonoli, Paul; Irby, Jim; Terry, Jim; Wallace, Greg; Vieira, Rui; Whyte, Dennis; Wolfe, Steve; Wukitch, Steve; Marmar, Earl

2015-11-01

The Advanced Divertor and RF Tokamak Experiment (ADX) is a design concept for a compact high-field tokamak that would address boundary plasma and plasma-material interaction physics challenges whose solution is critical for the viability of magnetic fusion energy. This device would have two crucial missions. First, it would serve as a Divertor Test Tokamak, developing divertor geometries, materials and operational scenarios that could meet the stringent requirements imposed in a fusion power plant. By operating at high field, ADX would address this problem at a level of power loading and other plasma conditions that are essentially identical to those expected in a future reactor. Secondly, ADX would investigate the physics and engineering of high-field-side launch of RF waves for current drive and heating. Efficient current drive is an essential element for achieving steady-state in a practical, power producing fusion device and high-field launch offers the prospect of higher efficiency, better control of the current profile and survivability of the launching structures. ADX would carry out this research in integrated scenarios that simultaneously demonstrate the required boundary regimes consistent with efficient current drive and core performance.

Chemical potential of quasi-equilibrium magnon gas driven by pure spin current.

PubMed

Demidov, V E; Urazhdin, S; Divinskiy, B; Bessonov, V D; Rinkevich, A B; Ustinov, V V; Demokritov, S O

2017-11-17

Pure spin currents provide the possibility to control the magnetization state of conducting and insulating magnetic materials. They allow one to increase or reduce the density of magnons, and achieve coherent dynamic states of magnetization reminiscent of the Bose-Einstein condensation. However, until now there was no direct evidence that the state of the magnon gas subjected to spin current can be treated thermodynamically. Here, we show experimentally that the spin current generated by the spin-Hall effect drives the magnon gas into a quasi-equilibrium state that can be described by the Bose-Einstein statistics. The magnon population function is characterized either by an increased effective chemical potential or by a reduced effective temperature, depending on the spin current polarization. In the former case, the chemical potential can closely approach, at large driving currents, the lowest-energy magnon state, indicating the possibility of spin current-driven Bose-Einstein condensation.

Driving Simulator Based Interactive Experiments : Understanding Driver Behavior, Cognition and Technology Uptake under Information and Communication Technologies

DOT National Transportation Integrated Search

2018-01-31

Advanced Traveler Information Systems (ATIS) and in-vehicle information systems (IVIS) are becoming an integral part of the current driving experience. Although information through in-vehicle technologies provides assistance to drivers with diverse t...

Modernization of the Driver Behaviour Questionnaire.

PubMed

Cordazzo, Sheila T D; Scialfa, Charles T; Ross, Rachel Jones

2016-02-01

The current study builds on previous versions of the Driver Behaviour Questionnaire (DBQ) by incorporating a larger sample of driving behaviors targeting inattention, distraction, aggressive driving, and health related to aging. The goals of this study were to determine if the resulting factor structure was consistent with a more contemporary view of unsafe driving behaviors, and to determine whether scores on the factors could predict self-reported collisions and police citations. The instrument was given to a sample of 3295 drivers ranging in age from 19 to 80+ years old. It was divided in two sections, the first to provide demographic information and driving history data and the second containing 105 driver behavior questions. An exploratory factor analysis resulted in a 65-item scale organized in four factors. The factors were labeled tentatively as Inattention Errors, Age-Related Problems, Distraction and Hurry, and Aggressive Violations. Regression analyses showed that the factors were predictors of self-reported, at-fault collisions and police citations. The factor scores found in this research are consistent with a useful theoretical framework for understanding unsafe driver actions, and demonstrate some potential to identify several individual difference variables that predict self-reported collisions and citations. Copyright © 2015 Elsevier Ltd. All rights reserved.

Combining axial and radial nanowire heterostructures: radial Esaki diodes and tunnel field-effect transistors.

PubMed

Dey, Anil W; Svensson, Johannes; Ek, Martin; Lind, Erik; Thelander, Claes; Wernersson, Lars-Erik

2013-01-01

The ever-growing demand on high-performance electronics has generated transistors with very impressive figures of merit (Radosavljevic et al., IEEE Int. Devices Meeting 2009, 1-4 and Cho et al., IEEE Int. Devices Meeting 2011, 15.1.1-15.1.4). The continued scaling of the supply voltage of field-effect transistors, such as tunnel field-effect transistors (TFETs), requires the implementation of advanced transistor architectures including FinFETs and nanowire devices. Moreover, integration of novel materials with high electron mobilities, such as III-V semiconductors and graphene, are also being considered to further enhance the device properties (del Alamo, Nature 2011, 479, 317-323, and Liao et al., Nature 2010, 467, 305-308). In nanowire devices, boosting the drive current at a fixed supply voltage or maintaining a constant drive current at a reduced supply voltage may be achieved by increasing the cross-sectional area of a device, however at the cost of deteriorated electrostatics. A gate-all-around nanowire device architecture is the most favorable electrostatic configuration to suppress short channel effects; however, the arrangement of arrays of parallel vertical nanowires to address the drive current predicament will require additional chip area. The use of a core-shell nanowire with a radial heterojunction in a transistor architecture provides an attractive means to address the drive current issue without compromising neither chip area nor device electrostatics. In addition to design advantages of a radial transistor architecture, we in this work illustrate the benefit in terms of drive current per unit chip area and compare the experimental data for axial GaSb/InAs Esaki diodes and TFETs to their radial counterparts and normalize the electrical data to the largest cross-sectional area of the nanowire, i.e. the occupied chip area, assuming a vertical device geometry. Our data on lateral devices show that radial Esaki diodes deliver almost 7 times higher peak current, Jpeak = 2310 kA/cm(2), than the maximum peak current of axial GaSb/InAs(Sb) Esaki diodes per unit chip area. The radial TFETs also deliver high peak current densities Jpeak = 1210 kA/cm(2), while their axial counterparts at most carry Jpeak = 77 kA/cm(2), normalized to the largest cross-sectional area of the nanowire.

A novel 3-TFT voltage driving method of compensating V TH shift for a-Si:H TFT and OLED degradation for AMOLED

NASA Astrophysics Data System (ADS)

Lin, Chih-Lung; Chou, Kuan-Wen; Chang, Fu-Chieh; Hung, Chia-Che

2011-10-01

This work demonstrates the feasibility of a novel pixel circuit by using three a-Si:H TFTs. The proposed circuit can stabilize the OLED current and provide an additional driving current to ameliorate the brightness degradation of the AMOLED. Measurement results indicate that the current degradation of the proposed circuit, caused by V TH variations, is less than 5% over more than 50,000 s at 60 °C, whereas that of a conventional 2T1C pixel circuit is larger than 34%. Furthermore, to ameliorate the decrease in luminance owing to the OLED degradation, the OLED current can be increased by 10% by analyzing the current degradation and modulating the detected voltage appropriately.

Impaired color naming of food and body shape words: weight phobia or distinct affective state?

PubMed

Green, M W; Elliman, N A; Rogers, P J; Welch, D A

1997-01-01

The current study investigated whether a concern with body shape and weight represents a distinct affective state, or whether it is better conceptualized as a highly specific form of anxiety. The color-naming performance of women with a high Drive for Thinness score was examined under three experimental conditions: when a photograph of chocolate was present, when actual chocolate was present, and a control condition. High Drive for Thinness subjects demonstrated relatively impaired color naming of body shape words in the picture condition, but not in the food or control conditions. Although there was a significant impairment in the color naming of food words, this was unaffected by condition or degree of Drive for Thinness. The results are interpreted as supporting an analogy between weight/body shape concerns and subclinical phobic anxiety.

Cell Phone Ring Suppression and HUD Caller ID: Effectiveness in Reducing Momentary Driver Distraction under Varying Workload Levels

NASA Astrophysics Data System (ADS)

Nowakowski, C.; Friedman, D.; Green, P.

2001-10-01

The purpose of the current experiment is to provide a preliminary driving simulator assessment of several hands-free design solutions with regard to the task of answering the phone while driving. Specifically, the following questions were examined: (1) Does the location of a caller ID display and the phone buttons (two HUD (Head Up Display) locations vs. phone cradle) affect either the time to answer the phone or driving performance; (2) Does the presence or absence of a ring affect either the time to answer the phone or driving performance; (3) Does increased driving workload (visual demand) affect either the time to answer the phone or driving performance; (4) What were the initial driver reactions to a HUD-based call timer.

How sleep problems contribute to simulator sickness: Preliminary results from a realistic driving scenario.

PubMed

Altena, Ellemarije; Daviaux, Yannick; Sanz-Arigita, Ernesto; Bonhomme, Emilien; de Sevin, Étienne; Micoulaud-Franchi, Jean-Arthur; Bioulac, Stéphanie; Philip, Pierre

2018-04-17

Virtual reality and simulation tools enable us to assess daytime functioning in environments that simulate real life as close as possible. Simulator sickness, however, poses a problem in the application of these tools, and has been related to pre-existing health problems. How sleep problems contribute to simulator sickness has not yet been investigated. In the current study, 20 female chronic insomnia patients and 32 female age-matched controls drove in a driving simulator covering realistic city, country and highway scenes. Fifty percent of the insomnia patients as opposed to 12.5% of controls reported excessive simulator sickness leading to experiment withdrawal. In the remaining participants, patients with insomnia showed overall increased levels of oculomotor symptoms even before driving, while nausea symptoms further increased after driving. These results, as well as the realistic simulation paradigm developed, give more insight on how vestibular and oculomotor functions as well as interoceptive functions are affected in insomnia. Importantly, our results have direct implications for both the actual driving experience and the wider context of deploying simulation techniques to mimic real life functioning, in particular in those professions often exposed to sleep problems. © 2018 European Sleep Research Society.

Examining signs of driver sleepiness, usage of sleepiness countermeasures and the associations with sleepy driving behaviours and individual factors.

PubMed

Watling, Christopher N; Armstrong, Kerry A; Radun, Igor

2015-12-01

The impairing effect from sleepiness is a major contributor to road crashes. The ability of a sleepy driver to perceive their level of sleepiness is an important consideration for road safety as well as the type of sleepiness countermeasure used by drivers as some sleepiness countermeasures are more effective than others. The aims of the current study were to determine the extent that the signs of driver sleepiness were associated with sleepy driving behaviours, as well as determining which individual factors (demographic, work, driving, and sleep-related factors) were associated with using a roadside or in-vehicle sleepiness countermeasure. A sample of 1518 Australian drivers from the Australian State of New South Wales and the neighbouring Australian Capital Territory took part in the study. The participants' experiences with the signs of sleepiness were reasonably extensive. A number of the early signs of sleepiness (e.g., yawning, frequent eye blinks) were related with continuing to drive while sleepy, with the more advanced signs of sleepiness (e.g., difficulty keeping eyes open, dreamlike state of consciousness) associated with having a sleep-related close call. The individual factors associated with using a roadside sleepiness countermeasure included age (being older), education (tertiary level), difficulties getting to sleep, not continuing to drive while sleepy, and having experienced many signs of sleepiness. The results suggest that these participants have a reasonable awareness and experience with the signs of driver sleepiness. Factors related to previous experiences with sleepiness were associated with implementing a roadside countermeasure. Nonetheless, the high proportions of drivers performing sleepy driving behaviours suggest that concerted efforts are needed with road safety campaigns regarding the dangers of driving while sleepy. Copyright © 2015 Elsevier Ltd. All rights reserved.

Heating and current drive requirements towards steady state operation in ITER

NASA Astrophysics Data System (ADS)

Poli, F. M.; Bonoli, P. T.; Kessel, C. E.; Batchelor, D. B.; Gorelenkova, M.; Harvey, B.; Petrov, Y.

2014-02-01

Steady state scenarios envisaged for ITER aim at optimizing the bootstrap current, while maintaining sufficient confinement and stability to provide the necessary fusion yield. Non-inductive scenarios will need to operate with Internal Transport Barriers (ITBs) in order to reach adequate fusion gain at typical currents of 9 MA. However, the large pressure gradients associated with ITBs in regions of weak or negative magnetic shear can be conducive to ideal MHD instabilities, reducing the no-wall limit. The E × B flow shear from toroidal plasma rotation is expected to be low in ITER, with a major role in the ITB dynamics being played by magnetic geometry. Combinations of H/CD sources that maintain weakly reversed magnetic shear profiles throughout the discharge are the focus of this work. Time-dependent transport simulations indicate that, with a trade-off of the EC equatorial and upper launcher, the formation and sustainment of quasi-steady state ITBs could be demonstrated in ITER with the baseline heating configuration. However, with proper constraints from peeling-ballooning theory on the pedestal width and height, the fusion gain and the maximum non-inductive current are below the ITER target. Upgrades of the heating and current drive system in ITER, like the use of Lower Hybrid current drive, could overcome these limitations, sustaining higher non-inductive current and confinement, more expanded ITBs which are ideal MHD stable.

Predictions for the drive capabilities of the RancheroS Flux Compression Generator into various load inductances using the Eulerian AMR Code Roxane

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

Watt, Robert Gregory

The Ranchero Magnetic Flux Compression Generator (FCG) has been used to create current pulses in the 10-­100 MA range for driving both “static” low inductance (0.5 nH) loads1 for generator demonstration purposes and high inductance (10-­20 nH) imploding liner loads2 for ultimate use in physics experiments at very high energy density. Simulations of the standard Ranchero generator have recently shown that it had a design issue that could lead to flux trapping in the generator, and a non-­ robust predictability in its use in high energy density experiments. A re-­examination of the design concept for the standard Ranchero generator, promptedmore » by the possible appearance of an aneurism at the output glide plane, has led to a new generation of Ranchero generators designated the RancheroS (for swooped). This generator has removed the problematic output glide plane and replaced it with a region of constantly increasing diameter in the output end of the FCG cavity in which the armature is driven outward under the influence of an additional HE load not present in the original Ranchero. The resultant RancheroS generator, to be tested in LA43S-­L13, probably in early FY17, has a significantly increased initial inductance and may be able to drive a somewhat higher load inductance than the standard Ranchero. This report will use the Eulerian AMR code Roxane to study the ability of the new design to drive static loads, with a goal of providing a database corresponding to the load inductances for which the generator might be used and the anticipated peak currents such loads might produce in physics experiments. Such a database, combined with a simple analytic model of an ideal generator, where d(LI)/dt = 0, and supplemented by earlier estimates of losses in actual use of the standard Ranchero, scaled to estimate the increase in losses due to the longer current carrying perimeter in the RancheroS, can then be used to bound the expectations for the current drive one may apply to any load assembly in future experiments.« less

Role of driver hearing in commercial motor vehicle operation : an evaluation of the FHWA hearing requirement

DOT National Transportation Integrated Search

1998-11-01

The Federal Highway Administration (FHWA) currently requires that all commercial motor vehicle (CMV) drivers have a specified minimum level of hearing to drive in interstate commerce. This tech brief summarizes an FHWA study of the same title that ev...

Sex Differences in Placental Mitochondrial Function Associated with Ozone-Induced Fetal Growth Restriction.

EPA Science Inventory

Fetal growth restriction is a major underlying cause of infant mortality worldwide. Unfortunately little is known about the mechanisms that drive compromised growth and the role of placental maladaptation on fetal development. In the current study placentas from male and female r...

Driving with pets and motor vehicle collision involvement among older drivers: A prospective population-based study.

PubMed

Huisingh, Carrie; Levitan, Emily B; Irvin, Marguerite R; Owsley, Cynthia; McGwin, Gerald

2016-03-01

Distracted driving is a major cause of motor vehicle collision (MVC) involvement. Pets have been identified as potential distraction to drivers, particularly in the front. This type of distraction could be worse for those with impairment in the cognitive aspects of visual processing. The purpose of this study is to evaluate the association between driving with pets and rates of motor vehicle collision involvement in a cohort of older drivers. A three-year prospective study was conducted in a population-based sample of 2000 licensed drivers aged 70 years and older. At the baseline visit, a trained interviewer asked participants about pet ownership, whether they drive with pets, how frequently, and where the pet sits in the vehicle. Motor vehicle collision (MVC) involvement during the three-year study period was obtained from the Alabama Department of Public Safety. At-fault status was determined by the police officer who arrived on the scene. Participants were followed until the earliest of death, driving cessation, or end of the study period. Poisson regression was used to calculate crude and adjusted rate ratios (RR) examining the association between pet ownership, presence of a pet in a vehicle, frequency of driving with a pet, and location of the pet inside with vehicle with any and at-fault MVC involvement. We examined whether the associations differed by higher order visual processing impairment status, as measured by Useful Field of View, Trails B, and Motor-free Visual Perception Test. Rates of crash involvement were similar for older adults who have ever driven with a pet compared to those who never drove with their pet (RR=1.15, 95% CI 0.76-1.75). Drivers who reported always or sometimes driving with their pet had higher MVC rates compared to pet owners who never drive with a pet, but this association was not statistically significant (RR=1.39, 95% CI 0.86-2.24). In terms of location, those reporting having a pet frequently ride in the front of the vehicle had similar rates of MVC involvement compared to those who did not drive with a pet in the front. A similar pattern of results was observed for at-fault MVCs. This association was not modified by visual processing impairment status. The current study demonstrates a positive but non-significant association between frequently driving with pets and MVC involvement. More research is needed, particularly on restraint use and whether the pet was in the car at the time of the crash, to help characterize the public safety benefit of regulations on driving with pets. Copyright © 2015 Elsevier Ltd. All rights reserved.

Changes in Classes of Injury-Related Risks and Consequences of Risk-Level Drinking: a Latent Transition Analysis.

PubMed

Cochran, Gerald; Field, Craig; Caetano, Raul

2015-07-01

Risk-level drinking, drinking and driving, and alcohol-related violence are risk factors that result in injuries. The current study sought to identify which subgroups of patients experience the most behavioral change following a brief intervention. A secondary analysis of data from a brief alcohol intervention study was conducted. The sample (N = 664) includes at-risk drinkers who experienced an injury and were admitted for care to a Level 1 trauma center. Injury-related items from the Short Inventory of Problems+6 were used to perform a latent transition analysis to describe class transitions participants experienced following discharge. Four classes emerged for the year before and after the current injury. Most individuals transitioned from higher-risk classes into those with lower risk. Some participants maintained risky profiles, and others increased risks and consequences. Drinking and driving remained a persistent problem among the study participants. Although a large portion of intervention recipients improved risks and consequences of alcohol use following discharge, more intensive intervention services may be needed for a subset of patients who showed little or no improvement.

Situated Word Learning: Words of the Year (WsOY) and Social Studies Inquiry

ERIC Educational Resources Information Center

Heafner, Tina L.; Triplett, Nicholas; Handler, Laura; Massey, Dixie

2018-01-01

Current events influence public interest and drive Internet word searches. For over a decade, linguists and dictionary publishers have analyzed big data from Internet word searches to designate "Words of the Year" (WsOY). In this study, we examine how WsOY can foster critical digital literacy and illuminate essential aspects of inquiry…

Are Sex Drive and Hypersexuality Associated with Pedophilic Interest and Child Sexual Abuse in a Male Community Sample?

PubMed

Klein, Verena; Schmidt, Alexander F; Turner, Daniel; Briken, Peer

2015-01-01

Although much is currently known about hypersexuality (in the form of excessive sexual behavior) among sexual offenders, the degree to which hypersexual behavior is linked to paraphilic and especially pedophilic interests in non-forensic populations has not been established.The purpose of the present study was to elucidate the associations between total sexual outlets(TSO) and other sex drive indicators, antisocial behavior, pedophilic interests, and sexual offending behavior in a large population-based community sample of males. The sample included 8,718 German men who participated in an online study. Hypersexual behavior as measured by self-reported TSO, self-reported sex drive, criminal history, and pedophilic interests were assessed. In moderated hierarchical logistic regression analyses self-reported contact sexual offending against children was linked to sexual fantasizing about children and anti sociality.There was no association between aggregated sex drive, and sexual abusive behaviour in the multivariate analyses. In contrast, self-reported child pornography consumption was associated with sex drive, sexual fantasies involving children, and anti sociality. Nevertheless, in convicted sexual offenders anti sociality, sexual preoccupation (like hypersexuality), and pedophilic interest are important predictors of sexual reoffending against prepubescent children.Therefore, in clinical practice an assessment of criminal history and pedophilic interests in hypersexual individuals and vice versa hypersexuality in antisocial or pedophilic men should be considered [corrected].

A Drive Method for Small Inductance PM Motor Under No-Load Condition

NASA Astrophysics Data System (ADS)

Tanaka, Daisuke; Ohishi, Kiyoshi

The harmonic wave of the exciting current of the motor is generated by the pulsewidth modulated voltage of the inverter. The motors that have low inpedance genetate more harmonics and make larger iron loss. This paper describes an implementation of drive control for a small inductance permanent-magnet motor drive. A comparative experiment has been carried out with conventional methods and the utility of the proposed method has been verified.

Gender differences in highway driving performance after administration of sleep medication: a review of the literature.

PubMed

Verster, Joris C; Roth, Thomas

2012-01-01

It is generally assumed that there are minimal gender differences in the safety and efficacy of central nervous system drugs, as is evidenced by men and women receiving the same drug dosage. There is, however, evidence that drugs may have a differential effect on performance in men and women, given reported differences in pharmacokinetics as well as the presence or absence and severity of adverse effects. It is especially important to verify whether gender differences in performance exist in case of activities that have potentially dangerous outcomes such as driving a car. This review summarizes the current scientific evidence on gender differences in driving performance after treatment with hypnotic drugs. A literature search was conducted to obtain all studies that conducted on-road driving tests to examine the effects hypnotic drugs on driving. Cross-references were checked and technical reports and raw data were obtained, if possible. Fourteen studies were evaluated. Many studies did not allow analyses of gender effects because only women were included. Others did not report data on gender analyses. Technical reports and additional data analyses revealed significant gender differences in driving performance the morning following bedtime administration of flurazepam (30 mg) and after middle-of-the-night administration of zolpidem (10 mg). No significant gender differences were found for ramelteon (8 mg), lormetazepam (1 and 2 mg), zaleplon (10 and 20 mg), and zopiclone (7.5 mg). Although the available data are limited, the results show that significant gender differences have been found for some drugs but not others. Therefore, in the future more research is needed to reveal potential gender differences and to determine what mediates them.

Cannabis Effects on Driving Skills

PubMed Central

Hartman, Rebecca L.; Huestis, Marilyn A.

2013-01-01

BACKGROUND Cannabis is the most prevalent illicit drug identified in impaired drivers. The effects of cannabis on driving continue to be debated, making prosecution and legislation difficult. Historically, delays in sample collection, evaluating the inactive Δ9-tetrahydrocannabinol (THC) metabolite 11-nor-9-carboxy-THC, and polydrug use have complicated epidemiologic evaluations of driver impairment after cannabis use. CONTENT We review and evaluate the current literature on cannabis’ effects on driving, highlighting the epidemiologic and experimental data. Epidemiologic data show that the risk of involvement in a motor vehicle accident (MVA) increases approximately 2-fold after cannabis smoking. The adjusted risk of driver culpability also increases substantially, particularly with increased blood THC concentrations. Studies that have used urine as the biological matrix have not shown an association between cannabis and crash risk. Experimental data show that drivers attempt to compensate by driving more slowly after smoking cannabis, but control deteriorates with increasing task complexity. Cannabis smoking increases lane weaving and impaired cognitive function. Critical-tracking tests, reaction times, divided-attention tasks, and lane-position variability all show cannabis-induced impairment. Despite purported tolerance in frequent smokers, complex tasks still show impairment. Combining cannabis with alcohol enhances impairment, especially lane weaving. SUMMARY Differences in study designs frequently account for inconsistencies in results between studies. Participant-selection bias and confounding factors attenuate ostensible cannabis effects, but the association with MVA often retains significance. Evidence suggests recent smoking and/or blood THC concentrations 2–5 ng/mL are associated with substantial driving impairment, particularly in occasional smokers. Future cannabis-and-driving research should emphasize challenging tasks, such as divided attention, and include occasional and chronic daily cannabis smokers. PMID:23220273

Seabird diversity hotspot linked to ocean productivity in the Canary Current Large Marine Ecosystem

PubMed Central

Attrill, Martin J.; Becker, Peter H.; Egevang, Carsten; Furness, Robert W.; Grémillet, David; Kopp, Matthias; Lescroël, Amélie; Matthiopoulos, Jason; Peter, Hans-Ulrich; Phillips, Richard A.

2016-01-01

Upwelling regions are highly productive habitats targeted by wide-ranging marine predators and industrial fisheries. In this study, we track the migratory movements of eight seabird species from across the Atlantic; quantify overlap with the Canary Current Large Marine Ecosystem (CCLME) and determine the habitat characteristics that drive this association. Our results indicate the CCLME is a biodiversity hotspot for migratory seabirds; all tracked species and more than 70% of individuals used this upwelling region. Relative species richness peaked in areas where sea surface temperature averaged between 15 and 20°C, and correlated positively with chlorophyll a, revealing the optimum conditions driving bottom-up trophic effects for seabirds. Marine vertebrates are not confined by international boundaries, making conservation challenging. However, by linking diversity to ocean productivity, our research reveals the significance of the CCLME for seabird populations from across the Atlantic, making it a priority for conservation action. PMID:27531154

Seabird diversity hotspot linked to ocean productivity in the Canary Current Large Marine Ecosystem.

PubMed

Grecian, W James; Witt, Matthew J; Attrill, Martin J; Bearhop, Stuart; Becker, Peter H; Egevang, Carsten; Furness, Robert W; Godley, Brendan J; González-Solís, Jacob; Grémillet, David; Kopp, Matthias; Lescroël, Amélie; Matthiopoulos, Jason; Patrick, Samantha C; Peter, Hans-Ulrich; Phillips, Richard A; Stenhouse, Iain J; Votier, Stephen C

2016-08-01

Upwelling regions are highly productive habitats targeted by wide-ranging marine predators and industrial fisheries. In this study, we track the migratory movements of eight seabird species from across the Atlantic; quantify overlap with the Canary Current Large Marine Ecosystem (CCLME) and determine the habitat characteristics that drive this association. Our results indicate the CCLME is a biodiversity hotspot for migratory seabirds; all tracked species and more than 70% of individuals used this upwelling region. Relative species richness peaked in areas where sea surface temperature averaged between 15 and 20°C, and correlated positively with chlorophyll a, revealing the optimum conditions driving bottom-up trophic effects for seabirds. Marine vertebrates are not confined by international boundaries, making conservation challenging. However, by linking diversity to ocean productivity, our research reveals the significance of the CCLME for seabird populations from across the Atlantic, making it a priority for conservation action. © 2016 The Authors.

Spectral gain profile of a multi-stack terahertz quantum cascade laser

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

Bachmann, D., E-mail: dominic.bachmann@tuwien.ac.at; Deutsch, C.; Krall, M.

2014-11-03

The spectral gain of a multi-stack terahertz quantum cascade laser, composed of three active regions with emission frequencies centered at 2.3, 2.7, and 3.0 THz, is studied as a function of driving current and temperature using terahertz time-domain spectroscopy. The optical gain associated with the particular quantum cascade stacks clamps at different driving currents and saturates to different values. We attribute these observations to varying pumping efficiencies of the respective upper laser states and to frequency dependent optical losses. The multi-stack active region exhibits a spectral gain full width at half-maximum of 1.1 THz. Bandwidth and spectral position of themore » measured gain match with the broadband laser emission. As the laser action ceases with increasing operating temperature, the gain at the dominant lasing frequency of 2.65 THz degrades sharply.« less

Geometric scalings for the electrostatically driven helical plasma state

NASA Astrophysics Data System (ADS)

Akçay, Cihan; Finn, John M.; Nebel, Richard A.; Barnes, Daniel C.

2017-12-01

A new plasma state has been investigated [Akcay et al., Phys. Plasmas 24, 052503 (2017)], with a uniform applied axial magnetic field in a periodic cylinder of length L = 2 π R , driven by helical electrodes. The drive is single helicity, depending on m θ + k z = m θ - n ζ , where ζ = z / R and k = - n / R . For strong ( m , n ) = ( 1 , 1 ) drive, the state was found to have a strong axial mean current density, with a mean-field safety factor q 0 ( r ) just above the pitch of the electrodes m / n = 1 in the interior. This state has possible applications to DC electrical transformers and tailoring of the current profile in tokamaks. We study two geometric issues of interest for these applications: (i) scaling of properties with the plasma length or aspect ratio and (ii) behavior for different helicities, specifically ( m , n ) = ( 1 , n ) for n > 1 and ( m , n ) = ( 2 , 1 ) .

Coherent nonhelical shear dynamos driven by magnetic fluctuations at low Reynolds numbers

DOE PAGES

Squire, J.; Bhattacharjee, A.

2015-10-28

Nonhelical shear dynamos are studied with a particular focus on the possibility of coherent dynamo action. The primary results—serving as a follow up to the results of Squire & Bhattacharjee—pertain to the "magnetic shear-current effect" as a viable mechanism to drive large-scale magnetic field generation. This effect raises the interesting possibility that the saturated state of the small-scale dynamo could drive large-scale dynamo action, and is likely to be important in the unstratified regions of accretion disk turbulence. In this paper, the effect is studied at low Reynolds numbers, removing the complications of small-scale dynamo excitation and aiding analysis bymore » enabling the use of quasi-linear statistical simulation methods. In addition to the magnetically driven dynamo, new results on the kinematic nonhelical shear dynamo are presented. Furthermore, these illustrate the relationship between coherent and incoherent driving in such dynamos, demonstrating the importance of rotation in determining the relative dominance of each mechanism.« less

COHERENT NONHELICAL SHEAR DYNAMOS DRIVEN BY MAGNETIC FLUCTUATIONS AT LOW REYNOLDS NUMBERS

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

Squire, J.; Bhattacharjee, A., E-mail: jsquire@caltech.edu

2015-11-01

Nonhelical shear dynamos are studied with a particular focus on the possibility of coherent dynamo action. The primary results—serving as a follow up to the results of Squire and Bhattacharjee—pertain to the “magnetic shear-current effect” as a viable mechanism to drive large-scale magnetic field generation. This effect raises the interesting possibility that the saturated state of the small-scale dynamo could drive large-scale dynamo action, and is likely to be important in the unstratified regions of accretion disk turbulence. In this paper, the effect is studied at low Reynolds numbers, removing the complications of small-scale dynamo excitation and aiding analysis bymore » enabling the use of quasi-linear statistical simulation methods. In addition to the magnetically driven dynamo, new results on the kinematic nonhelical shear dynamo are presented. These illustrate the relationship between coherent and incoherent driving in such dynamos, demonstrating the importance of rotation in determining the relative dominance of each mechanism.« less

Rotating rake design for unique measurement of fan-generated spinning acoustic modes

NASA Technical Reports Server (NTRS)

Konno, Kevin E.; Hausmann, Clifford R.

1993-01-01

In light of the current emphasis on noise reduction in subsonic aircraft design, NASA has been actively studying the source of and propagation of noise generated by subsonic fan engines. NASA/LeRC has developed and tested a unique method of accurately measuring these spinning acoustic modes generated by an experimental fan. This mode measuring method is based on the use of a rotating microphone rake. Testing was conducted in the 9 x 15 Low-speed Wind Tunnel. The rotating rake was tested with the Advanced Ducted Propeller (ADP) model. This memorandum discusses the design and performance of the motor/drive system for the fan-synchronized rotating acoustic rake. This novel motor/drive design approach is now being adapted for additional acoustic mode studies in new test rigs as baseline data for the future design of active noise control for subsonic fan engines. Included in this memorandum are the research requirements, motor/drive specifications, test performance results, and a description of the controls and software involved.

Driving in Early-Stage Alzheimer's Disease: An Integrative Review of the Literature.

PubMed

Davis, Rebecca L; Ohman, Jennifer M

2017-03-01

One of the most difficult decisions for individuals with Alzheimer's disease (AD) is when to stop driving. Because driving is a fundamental activity linked to socialization, independent functioning, and well-being, making the decision to stop driving is not easy. Cognitive decline in older adults can lead to getting lost while driving, difficulty detecting and avoiding hazards, as well as increased errors while driving due to compromised judgment and difficulty in making decisions. The purpose of the current literature review was to synthesize evidence regarding how individuals with early-stage AD, their families, and providers make determinations about driving safety, interventions to increase driving safety, and methods to assist cessation and coping for individuals with early-stage AD. The evidence shows that changes in driving ability start early and progress throughout the trajectory of AD. Some individuals with mild cognitive impairment or early-stage AD may be safe to drive for a period of time. Support groups aimed at helping with the transition have been shown to be helpful for individuals who stop driving. Research and practice must support interventions to help individuals maintain safety while driving, as well as cope with driving cessation. [Res Gerontol Nurs. 2017; 10(2):86-100.]. Copyright 2016, SLACK Incorporated.

Alcohol control in Virginia : planning documents for use by agencies of the Commonwealth.

DOT National Transportation Integrated Search

1982-01-01

The Governor's Task Force to Combat Drunk Driving was created to confront the problem of drunken driving in Virginia, and to ascertain Virginia's current efforts to address this problem so that these efforts could be assessed and appropriate changes ...

Flow enhancement of deformable self-driven objects by countercurrent

NASA Astrophysics Data System (ADS)

Mashiko, Takashi; Fujiwara, Takashi

2016-10-01

We report numerical simulations of the mixed flows of two groups of deformable self-driven objects. The objects belonging to the group A (B) have drift coefficient D =DA (DB), where a positive (negative) value of D denotes the rightward (leftward) driving force. For co-current flows (DA ,DB > 0), the result is rather intuitive: the net flow of one group (QA) increases if the driving force of the other group is stronger than its own driving force (i.e., DB >DA), and decreases otherwise (DB

Why Do Drivers Use Mobile Phones While Driving? The Contribution of Compensatory Beliefs

PubMed Central

Zhou, Ronggang; Yu, Mengli; Wang, Xinyi

2016-01-01

The current study is the first to investigate the contribution of compensatory beliefs (i.e., the belief that the negative effects of an unsafe behavior can be "neutralized" by engaging in another safe behavior; e.g., "I can use a mobile phone now because I will slow down ") on drivers’ mobile phone use while driving. The effects of drivers’ personal characteristics on compensatory beliefs, mobile phone use and self-regulatory behaviors were also examined. A series of questions were administered to drivers, which included (1) personal measures, (2) scales that measured compensatory beliefs generally in substance use and with regard to driving safety, and (3) questions to measure drivers’ previous primary mobile phone usage and corresponding self-regulatory actions. Overall, drivers reported a low likelihood of compensatory beliefs, prior mobile phone use, and a strong frequency of self-regulatory behaviors. Respondents who had a higher tendency toward compensatory beliefs reported more incidents or crash involvement caused by making or answering calls and sending or reading messages. The findings provide strong support for the contribution of compensatory beliefs in predicting mobile phone usage in the context of driving. Compensatory beliefs can explain 41% and 43% of the variance in the active activities of making calls and texting/sending messages compared with 18% and 31% of the variance in the passive activities of answering calls and reading messages. Among the regression models for predicting self-regulatory behaviors at the tactical or operational level, compensatory beliefs emerge as significant predictors only in predicting shorter conversations while on a call. The findings and limitations of the current study are discussed. PMID:27494524

The impact of childhood symptoms of conduct disorder on driver aggression in adulthood.

PubMed

Wickens, Christine M; Vingilis, Evelyn; Mann, Robert E; Erickson, Patricia; Toplak, Maggie E; Kolla, Nathan J; Seeley, Jane; Ialomiteanu, Anca R; Stoduto, Gina; Ilie, Gabriela

2015-05-01

Despite limited empirical investigation, existing scientific literature suggests that individuals with a history or current diagnosis of conduct disorder (CD) may be more likely to demonstrate reckless and aggressive driving. Much of the limited research in this field examines the impact of childhood CD on driver behaviour and collision risk in young adults. Few if any, studies assess the impact of this disorder on driver behaviour beyond age 21 years. The current research is a population-based study of the impact of CD symptoms during childhood on the risk of engaging in driver aggression during adulthood. Data are based on telephone interviews with 5230 respondents who reported having driven in the past year. Data are derived from the 2011-2013 cycles of the CAMH Monitor, an ongoing cross-sectional survey of adults in Ontario, Canada aged 18 years and older. A binary logistic regression analysis of self-reported driver aggression in the previous 12 months was conducted, consisting of measures of demographic characteristics, driving exposure, problem substance use, alcohol- and drug-impaired driving, symptoms of attention deficit hyperactivity disorder, and childhood (before age 15) symptoms of CD. When entered with demographic characteristics, driving exposure, and other potential confounders, childhood symptoms of CD increased the odds of reporting driver aggression more than two-fold (adjusted OR=2.12). Exploratory analyses of the interaction between childhood symptoms of CD and age was not a significant predictor of driver aggression. Results suggest that symptoms of CD during childhood are associated with significantly increased odds of self-reported driver aggression during adulthood. Limitations and future directions of the research are discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

The Dynomak: An advanced spheromak reactor system with imposed-dynamo current drive and next-generation nuclear power technologies

NASA Astrophysics Data System (ADS)

Sutherland, D. A.; Jarboe, T. R.; Marklin, G.; Morgan, K. D.; Nelson, B. A.

2013-10-01

A high-beta spheromak reactor system has been designed with an overnight capital cost that is competitive with conventional power sources. This reactor system utilizes recently discovered imposed-dynamo current drive (IDCD) and a molten salt blanket system for first wall cooling, neutron moderation and tritium breeding. Currently available materials and ITER developed cryogenic pumping systems were implemented in this design on the basis of technological feasibility. A tritium breeding ratio of greater than 1.1 has been calculated using a Monte Carlo N-Particle (MCNP5) neutron transport simulation. High-temperature superconducting tapes (YBCO) were used for the equilibrium coil set, substantially reducing the recirculating power fraction when compared to previous spheromak reactor studies. Using zirconium hydride for neutron shielding, a limiting equilibrium coil lifetime of at least thirty full-power years has been achieved. The primary FLiBe loop was coupled to a supercritical carbon dioxide Brayton cycle due to attractive economics and high thermal efficiencies. With these advancements, an electrical output of 1000 MW from a thermal output of 2486 MW was achieved, yielding an overall plant efficiency of approximately 40%. A paper concerning the Dynomak reactor design is currently being reviewed for publication.

Driver training interests of a Spanish sample of young drivers and its relationship with their self-assessment skills concerning risky driving behavior.

PubMed

Molina, J Gabriel; Sanmartín, Jaime; Keskinen, Esko

2013-03-01

Poor driving self-assessment skills (e.g., over-confidence) have been pointed out as an important explanatory factor behind young drivers' accident involvement. This paper explores (1) what young drivers miss in their training as drivers in order to analyze whether an assessment of one's own driving skills plays an important role in their desire to improve as drivers, and (2) how these training interests are related to an estimate of their self-assessment skills concerning risky driving behavior. For this purpose, a study was conducted using a survey with a blocked sampling design of novice drivers. The survey solicited respondents' self-report about (1) the contents of training courses that they feel would improve their driving, (2) their risky driving behavior, and (3) their likelihood of being involved in a risky driving situation. From the initial sample invited to participate, of nearly 1300 people, we finally obtained complete data from 321 young Spanish drivers. Two main results were apparent from our data analysis: (1) the novice drivers were mainly interested in improving their ability to recognize their strengths and weaknesses as drivers (i.e., self-assessment skills); (2) a significant relationship was found between novice drivers' interests and their current self-assessment skills concerning risky driving behavior. Specifically, there was greater general interest expressed in post-license training by the under-confident self-assessors than the over-confident ones. These results provide a relevant input which should be taken into account when designing driver training programs for novice drivers. Moreover, the relationship between their training interests and their risky driving self-assessment skills introduces an additional factor to be considered in the implementation of these training programs. Copyright © 2012 Elsevier Ltd. All rights reserved.

System simulation of direct-current speed regulation based on Simulink

NASA Astrophysics Data System (ADS)

Yang, Meiying

2018-06-01

Many production machines require the smooth adjustment of speed in a certain range In the process of modern industrial production, and require good steady-state and dynamic performance. Direct-current speed regulation system with wide speed regulation range, small relative speed variation, good stability, large overload capacity, can bear the frequent impact load, can realize stepless rapid starting-braking and inversion of frequency and other good dynamic performances, can meet the different kinds of special operation requirements in production process of automation system. The direct-current power drive system is almost always used in the field of drive technology of high performance for a long time.

Comparison between numerical and analytical results on the required rf current for stabilizing neoclassical tearing modes

NASA Astrophysics Data System (ADS)

Wang, Xiaojing; Yu, Qingquan; Zhang, Xiaodong; Zhang, Yang; Zhu, Sizheng; Wang, Xiaoguang; Wu, Bin

2018-04-01

Numerical studies on the stabilization of neoclassical tearing modes (NTMs) by electron cyclotron current drive (ECCD) have been carried out based on reduced MHD equations, focusing on the amount of the required driven current for mode stabilization and the comparison with analytical results. The dependence of the minimum driven current required for NTM stabilization on some parameters, including the bootstrap current density, radial width of the driven current, radial deviation of the driven current from the resonant surface, and the island width when applying ECCD, are studied. By fitting the numerical results, simple expressions for these dependences are obtained. Analysis based on the modified Rutherford equation (MRE) has also been carried out, and the corresponding results have the same trend as numerical ones, while a quantitative difference between them exists. This difference becomes smaller when the applied radio frequency (rf) current is smaller.

Latitude-dependent delay in the responses of the equatorial electrojet and Sq currents to X-class solar flares

NASA Astrophysics Data System (ADS)

Nogueira, Paulo A. B.; Abdu, Mangalathayil A.; Souza, Jonas R.; Denardini, Clezio M.; Barbosa Neto, Paulo F.; Serra de Souza da Costa, João P.; Silva, Ana P. M.

2018-01-01

We have analyzed low-latitude ionospheric current responses to two intense (X-class) solar flares that occurred on 13 May 2013 and 11 March 2015. Sudden intensifications, in response to solar flare radiation impulses, in the Sq and equatorial electrojet (EEJ) currents, as detected by magnetometers over equatorial and low-latitude sites in South America, are studied. In particular we show for the first time that a 5 to 8 min time delay is present in the peak effect in the EEJ, with respect that of Sq current outside the magnetic equator, in response to the flare radiation enhancement. The Sq current intensification peaks close to the flare X-ray peak, while the EEJ peak occurs 5 to 8 min later. We have used the Sheffield University Plasmasphere-Ionosphere Model at National Institute for Space Research (SUPIM-INPE) to simulate the E-region conductivity enhancement as caused by the flare enhanced solar extreme ultraviolet (EUV) and soft X-rays flux. We propose that the flare-induced enhancement in neutral wind occurring with a time delay (with respect to the flare radiation) could be responsible for a delayed zonal electric field disturbance driving the EEJ, in which the Cowling conductivity offers enhanced sensitivity to the driving zonal electric field.

Knowledge, attitudes, and practices around drinking and driving in Cambodia: 2010-2012.

PubMed

Bachani, A M; Risko, C B; Gnim, C; Coelho, S; Hyder, A A

2017-03-01

Road traffic injuries are a leading cause of disability and death in Cambodia. Economic development has long been associated with rapid increases in road traffic injuries and fatalities. Drink driving is of particular concern in Cambodia. In 2014, the percentage of fatal crashes involving alcohol rose to 17.5% (n = 381), representing a 34.9% (n = 253) increase from 2012. This study aims to illustrate current knowledge, attitudes and practices (KAP) around drinking and driving in three Cambodian provinces. A roadside survey of randomly selected road users (aged 18 years and older) was conducted in Phnom Penh, Kandal, and Kampong Speu, Cambodia, between November 2010 and May 2012. Data were collected for five-day periods every 6 months. A survey was administered to assess prevailing knowledge, attitudes, and practices surrounding drink driving. A total of 1187 road users responded to the KAP survey, the majority (49.6%, n = 585) of whom were from Phnom Penh. Males accounted for 96.2% (n = 1142) of respondents; the majority (63.8%, n = 757) were aged 34 years and younger. Despite the belief that drinking and driving would increase the risk of a crash, a significant proportion of respondents (37.1%, n = 438) reported driving within 2 h of drinking alcohol at least once in the 30 days preceding the survey. This proportion was particularly high among males aged 25-34 years at 49.2% (n = 208). Of those who reported drinking and driving, 76.5% (n = 335) indicated they 'felt conscious enough' to drive at the time and 34.0% (n = 149) reported having 'no other available transportation options'. This study shows that, in general, drinking and driving remains a problem in Cambodia. A multi-pronged, coordinated approach is needed to effectively address this issue. Such an approach ought to include social marketing and public education campaigns, enhanced enforcement, and programs that either limit the number of drinks to drivers or those that provide alternatives to drinking and driving. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Lower hybrid current drive in experiments for transport barriers at high βN of JET (Joint European Torus)

NASA Astrophysics Data System (ADS)

Cesario, R. C.; Castaldo, C.; Fonseca, A.; De Angelis, R.; Parail, V.; Smeulders, P.; Beurskens, M.; Brix, M.; Calabrò, G.; De Vries, P.; Mailloux, J.; Pericoli, V.; Ravera, G.; Zagorski, R.

2007-09-01

LHCD has been used in JET experiments aimed at producing internal transport barriers (ITBs) in highly triangular plasmas (δ≈0.4) at high βN (up to 3) for steady-state application. The LHCD is a potentially valuable tool for (i) modifying the target q-profile, which can help avoid deleterious MHD modes and favour the formation of ITBs, and (ii) contributing to the non-inductive current drive required to prolong such plasma regimes. The q-profile evolution has been simulated during the current ramp-up phase for such a discharge (B0 = 2.3 T, IP = 1.5 MA) where 2 MW of LHCD has been coupled. The JETTO code was used taking measured plasma profiles, and the LHCD profile modeled by the LHstar code. The results are in agreement with MSE measurements and indicate the importance of the elevated electron temperature due to LHCD, as well as the driven current. During main heating with 18 MW of NBI and 3 MW of ICRH the bootstrap current density at the edge also becomes large, consistently with the observed reduction of the local turbulence and of the MHD activity. JETTO modelling suggests that the bootstrap current can reduce the magnetic shear (sh) at large radius, potentially affecting the MHD stability and turbulence behaviour in this region. Keywords: lower hybrid current drive (LHCD), bootstrap current, q (safety factor) and shear (sh) profile evolutions.

Detecting and Quantifying Mind Wandering during Simulated Driving.

PubMed

Baldwin, Carryl L; Roberts, Daniel M; Barragan, Daniela; Lee, John D; Lerner, Neil; Higgins, James S

2017-01-01

Mind wandering is a pervasive threat to transportation safety, potentially accounting for a substantial number of crashes and fatalities. In the current study, mind wandering was induced through completion of the same task for 5 days, consisting of a 20-min monotonous freeway-driving scenario, a cognitive depletion task, and a repetition of the 20-min driving scenario driven in the reverse direction. Participants were periodically probed with auditory tones to self-report whether they were mind wandering or focused on the driving task. Self-reported mind wandering frequency was high, and did not statistically change over days of participation. For measures of driving performance, participant labeled periods of mind wandering were associated with reduced speed and reduced lane variability, in comparison to periods of on task performance. For measures of electrophysiology, periods of mind wandering were associated with increased power in the alpha band of the electroencephalogram (EEG), as well as a reduction in the magnitude of the P3a component of the event related potential (ERP) in response to the auditory probe. Results support that mind wandering has an impact on driving performance and the associated change in driver's attentional state is detectable in underlying brain physiology. Further, results suggest that detecting the internal cognitive state of humans is possible in a continuous task such as automobile driving. Identifying periods of likely mind wandering could serve as a useful research tool for assessment of driver attention, and could potentially lead to future in-vehicle safety countermeasures.

Detecting and Quantifying Mind Wandering during Simulated Driving

PubMed Central

Baldwin, Carryl L.; Roberts, Daniel M.; Barragan, Daniela; Lee, John D.; Lerner, Neil; Higgins, James S.

2017-01-01

Mind wandering is a pervasive threat to transportation safety, potentially accounting for a substantial number of crashes and fatalities. In the current study, mind wandering was induced through completion of the same task for 5 days, consisting of a 20-min monotonous freeway-driving scenario, a cognitive depletion task, and a repetition of the 20-min driving scenario driven in the reverse direction. Participants were periodically probed with auditory tones to self-report whether they were mind wandering or focused on the driving task. Self-reported mind wandering frequency was high, and did not statistically change over days of participation. For measures of driving performance, participant labeled periods of mind wandering were associated with reduced speed and reduced lane variability, in comparison to periods of on task performance. For measures of electrophysiology, periods of mind wandering were associated with increased power in the alpha band of the electroencephalogram (EEG), as well as a reduction in the magnitude of the P3a component of the event related potential (ERP) in response to the auditory probe. Results support that mind wandering has an impact on driving performance and the associated change in driver’s attentional state is detectable in underlying brain physiology. Further, results suggest that detecting the internal cognitive state of humans is possible in a continuous task such as automobile driving. Identifying periods of likely mind wandering could serve as a useful research tool for assessment of driver attention, and could potentially lead to future in-vehicle safety countermeasures. PMID:28848414

Transportation and Aging: An Updated Research Agenda to Advance Safe Mobility among Older Adults Transitioning From Driving to Non-driving.

PubMed

Dickerson, Anne E; Molnar, Lisa J; Bédard, Michel; Eby, David W; Berg-Weger, Marla; Choi, Moon; Grigg, Jenai; Horowitz, Amy; Meuser, Thomas; Myers, Anita; O'Connor, Melissa; Silverstein, Nina M

2017-07-29

Engagement in civic, social, and community life plays an important role in health, well-being, and quality of life, and requires individuals to be mobile in their environment. In this article, we review what is currently known about 2 areas relevant to safe mobility for older drivers and identify future research in these areas. Using a framework for transportation and safe mobility, 2 key areas were selected for review: the process of transitioning to non-driving and the maintenance of mobility after driving has ceased. This article serves as a companion to another article that used the same approach to explore safe mobility issues for older adults who are still driving. We found that although there has been progress in supporting transitioning process to non-driving and improving mobility options for older adults following driving cessation, many knowledge gaps still exist. We identified several research topics that would benefit from continued scientific inquiry. In addition, several themes emerged from the review, including the need for: multidisciplinary, community-wide solutions; large-scale, longitudinal studies; improved education and training for older adults and the variety of stakeholders involved in older adult transportation; and the need for programs and interventions that are flexible and responsive to individual needs and situational differences. © The Author 2017. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

A compact rail-to-rail CMOS buffer amplifier with very low quiescent current

NASA Astrophysics Data System (ADS)

Arslan, Emre; Yıldız, Merih; Minaei, Shahram

2015-06-01

In this work, a very compact, rail-to-rail, high-speed buffer amplifier for liquid crystal display (LCD) applications is proposed. Compared to other buffer amplifiers, the proposed circuit has a very simple architecture, occupies a small number of transistors and also has a large driving capacity with very low quiescent current. It is composed of two complementary differential input stages to provide rail-to-rail driving capacity. The push-pull transistors are directly connected to the differential input stage, and the output is taken from an inverter. The proposed buffer circuit is laid out using Mentor Graphics IC Station layout editor using AMS 0.35 μm process parameters. It is shown by post-layout simulations that the proposed buffer can drive a 1 nF capacitive load within a small settling time under a full voltage swing, while drawing only 1.6 μA quiescent current from a 3.3 V power supply.

Recent experimental results of KSTAR RF heating and current drive

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

Wang, S. J., E-mail: sjwang@nfri.re.kr; Kim, J.; Jeong, J. H.

2015-12-10

The overview of KSTAR activities on ICRH, LHCD and ECH/CD including the last experimental results and future plan aiming for long-pulse high-beta plasma will be presented. Recently we achieved reasonable coupling of ICRF power to H-mode plasma through several efforts to increase system reliability. Power balance will be discussed on this experiment. LHCD is still struggling in the low power regime. Review of antenna spectrum for the higher coupling in H-mode plasma will be tried. ECH/CD provides 41 sec, 0.8 MW of heating power to support high-performance long-pulse discharge. Also, 170 GHz ECH system is integrated with the Plasma Control Systemmore » (PCS) for the feedback controlling of NTM. Status and plan of ECH/CD will be discussed. Finally, helicon current drive is being prepared for the next stage of KSTAR operation. The hardware preparation and the calculation results of helicon current drive in KSTAR plasma will be discussed.« less

Novel Driving Method for Two-Dimensional and Three-Dimensional Switchable Active Matrix Organic Light-Emitting Diode Displays for Emission and Programming Time Extension

NASA Astrophysics Data System (ADS)

In, Hai-Jung; Kwon, Oh-Kyong

2012-03-01

A novel driving method for two-dimensional (2D) and three-dimensional (3D) switchable active matrix organic light-emitting diode (AMOLED) displays is proposed to extend emission time and data programming time during 3D display operation. The proposed pixel consists of six thin-film transistors (TFTs) and two capacitors, and the aperture ratio of the pixel is 45.8% under 40-in. full-high-definition television condition. By increasing emission time and programming time, the flicker problem can be reduced and the lifetime of AMOLED displays can be extended owing to the decrease in emission current density. Simulation results show that the emission current error range from -0.4 to 1.6% is achieved when the threshold voltage variation of driving TFTs is in the range from -1.0 to 1.0 V, and the emission current error is 1.0% when the power line IR-drop is 2.0 V.

Perceptual Adaptation to Sinewave-Vocoded Speech across Languages

ERIC Educational Resources Information Center

Bent, Tessa; Loebach, Jeremy L.; Phillips, Lawrence; Pisoni, David B.

2011-01-01

Listeners rapidly adapt to many forms of degraded speech. What level of information drives this adaptation, however, remains unresolved. The current study exposed listeners to sinewave-vocoded speech in one of three languages, which manipulated the type of information shared between the training languages (German, Mandarin, or English) and the…

Constructivism Pedagogy Drives Redevelopment of CAD Course: A Case Study

ERIC Educational Resources Information Center

Clemons, Stephanie A.

2006-01-01

Teacher and student roles continue to change as computers continue to influence the design curriculum (Kaplan, 1997). Educators and administrators continue to grapple with the best ways to teach, implement, and maintain current technology. Few technology teachers would argue that computers, software, and hardware found in technology laboratories…

Computational Modeling of Distinct Neocortical Oscillations Driven by Cell-Type Selective Optogenetic Drive: Separable Resonant Circuits Controlled by Low-Threshold Spiking and Fast-Spiking Interneurons

PubMed Central

Vierling-Claassen, Dorea; Cardin, Jessica A.; Moore, Christopher I.; Jones, Stephanie R.

2010-01-01

Selective optogenetic drive of fast-spiking (FS) interneurons (INs) leads to enhanced local field potential (LFP) power across the traditional “gamma” frequency band (20–80 Hz; Cardin et al., 2009). In contrast, drive to regular-spiking (RS) pyramidal cells enhances power at lower frequencies, with a peak at 8 Hz. The first result is consistent with previous computational studies emphasizing the role of FS and the time constant of GABAA synaptic inhibition in gamma rhythmicity. However, the same theoretical models do not typically predict low-frequency LFP enhancement with RS drive. To develop hypotheses as to how the same network can support these contrasting behaviors, we constructed a biophysically principled network model of primary somatosensory neocortex containing FS, RS, and low-threshold spiking (LTS) INs. Cells were modeled with detailed cell anatomy and physiology, multiple dendritic compartments, and included active somatic and dendritic ionic currents. Consistent with prior studies, the model demonstrated gamma resonance during FS drive, dependent on the time constant of GABAA inhibition induced by synchronous FS activity. Lower-frequency enhancement during RS drive was replicated only on inclusion of an inhibitory LTS population, whose activation was critically dependent on RS synchrony and evoked longer-lasting inhibition. Our results predict that differential recruitment of FS and LTS inhibitory populations is essential to the observed cortical dynamics and may provide a means for amplifying the natural expression of distinct oscillations in normal cortical processing. PMID:21152338

Driving simulation for evaluation and rehabilitation of driving after stroke.

PubMed

Akinwuntan, Abiodun Emmanuel; Wachtel, Jerry; Rosen, Peter Newman

2012-08-01

Driving is an important activity of daily living. Loss of driving privileges can lead to depression, decreased access to medical care, and increased healthcare costs. The ability to drive is often affected after stroke. In approximately 30% of stroke survivors, it is clear from the onset that driving will no longer be possible. Approximately 33% of survivors will be able to return to driving with little or no retraining, and 35% will require driving-related rehabilitation before they can resume safe driving again. The ability to drive is not routinely evaluated after stroke, and there is no established rehabilitation program for poststroke driving. When driving evaluation does occur, it is not always clear which tests are the most salient for accurately assessing poststroke driving ability. Investigators have examined the efficacy of various methodologies to predict driving performance after stroke and have found mixed results, with each method having unique weaknesses, including poor predictive ability, poor face validity, poor sensitivity or specificity, and limited reliability. Here we review common models of driving to gain insight into why single-construct visual or cognitive off-road measures are inadequate for evaluating driving, a complex and dynamic activity that involves timely interaction of multiple motor, visual, cognitive, and perceptual skills. We also examine the potential for driving simulators to overcome the problems currently faced in the evaluation and rehabilitation of driving after stroke. Finally, we offer suggestions for the future direction of simulator-based poststroke driving evaluation and training. Copyright © 2012 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Encouraging full time use of safety belts among current part-time users

DOT National Transportation Integrated Search

1991-01-01

A large percentage of drivers report using their seat belts only some of the time. Most part-time users report they buckle up only for highway driving because they believe that driving around their community does not expose them to a significant risk...

Links between casino proximity and gambling participation, expenditure, and pathology.

PubMed

Sévigny, Serge; Ladouceur, Robert; Jacques, Christian; Cantinotti, Michael

2008-06-01

Two studies investigated the relationship between casino proximity and gambling participation, expenditure, and pathology. In Study 1, 8,842 participants were categorized into 1 of 4 driving distances from their home to the nearest casino in the province of Quebec: 0-100 km, 100.01-200 km, 200.01-300 km, or 300.01-981 km. In Study 2, 5,158 participants, who lived within a 100-km driving distance from the Montreal casino, were classified into 1 of 5 equidistant, 20-km driving distances. A survey company interviewed participants regarding their gambling habits. Results indicated a positive link between casino proximity and gambling participation (at the provincial and Montreal levels) and expenditure (at the provincial level only) but no link with the current prevalence rate of probable pathological gambling or of problem gambling. In a setting in which many types of gambling activities are available, casino proximity in itself does not appear to explain the rate of gambling-related problems. It is necessary to continue prospective research on exposure and adaptation theories as potential explanations for the development of pathological gambling. 2008 APA

A novel robust speed controller scheme for PMBLDC motor.

PubMed

Thirusakthimurugan, P; Dananjayan, P

2007-10-01

The design of speed and position controllers for permanent magnet brushless DC motor (PMBLDC) drive remains as an open problem in the field of motor drives. A precise speed control of PMBLDC motor is complex due to nonlinear coupling between winding currents and rotor speed. In addition, the nonlinearity present in the developed torque due to magnetic saturation of the rotor further complicates this issue. This paper presents a novel control scheme to the conventional PMBLDC motor drive, which aims at improving the robustness by complete decoupling of the design besides minimizing the mutual influence among the speed and current control loops. The interesting feature of this robust control scheme is its suitability for both static and dynamic aspects. The effectiveness of the proposed robust speed control scheme is verified through simulations.

Driving with pets and motor vehicle collision involvement among older drivers: a prospective population-based study

PubMed Central

Huisingh, Carrie; Levitan, Emily B.; Irvin, Marguerite R.; Owsley, Cynthia; McGwin, Gerald

2016-01-01

Objective Distracted driving is a major cause of motor vehicle collision (MVC) involvement. Pets have been identified as potential distraction to drivers, particularly in the front. This type of distraction could be worse for those with impairment in the cognitive aspects of visual processing. The purpose of this study is to evaluate the association between driving with pets and rates of motor vehicle collision involvementin a cohort of older drivers. Methods A three-year prospective was conducted in a population-based sample of 2000 licensed drivers aged 70 years and older. At the baseline visit, a trained interviewer asked participants about pet ownership, whether they drive with pets, how frequently, and where the pet sits in the vehicle. Motor vehicle collision (MVC) involvement during the three-year study period was obtained from the Alabama Department of Public Safety. At-fault status was determined by the police officer who arrived on the scene. Participants were followed until the earliest of death, driving cessation, or end of the study period. Poisson regression was used to calculate crude and adjusted rate ratios (RR) examining the association between pet ownership, presence of a pet in a vehicle, frequency of driving with a pet, and location of the pet inside with vehicle with any and at-fault MVC involvement. We examined whether the associations differed by higher order visual processing impairment status, as measured by Useful Field Of View, Trails B, and Motor-free Visual Perception Test. Results Rates of crash involvement were similar for older adults who have ever driven with a pet compared to those who never drove with their pet (RR=1.15, 95% CI 0.76-1.75). Drivers who reported always or sometimes driving with their pet had higherMVC rates compared topet owners who never drive with a pet, but this association was not statistically significant (RR=1.39, 95% CI 0.86-2.24). In terms of location, those reporting having a pet frequently ride in the front of the vehicle had similar rates of MVC involvement compared to those who did not drive with a pet in the front. A similar pattern of results was observed for at-fault MVCs. This association was not modified by visual processing impairment status. Conclusion The current study demonstrates a positive but non-significant association between frequently driving with pets and MVC involvement. More research is needed, particularly on restraint use and whether the pet was in the car at the time of the crash, to help characterize the public safety benefit of regulations on driving with pets. PMID:26774042

Small Screen Use and Driving Safety.

PubMed

Atchley, Paul; Strayer, David L

2017-11-01

The increased availability of "small screens," wireless devices with Internet-enabled connections, and their associated applications has almost overnight changed the way that we interact with our phones. The current work outlines some of the aspects of this problem as it relates to the influence of small screens on driving safety. Small screens are highly compelling to drivers, both for the information they convey and because the ability to ignore them while driving is impaired by cognitive resources used by the driving task itself. However, much is unknown about why people make choices to multitask while driving. Given the safety risks, it is recommended that parents, the public, and regulators take a stand against the use of Internet-enabled small screens unrelated to driving when the vehicle is in motion. Copyright © 2017 by the American Academy of Pediatrics.

The Helicity Injected Torus (HIT) Program

NASA Astrophysics Data System (ADS)

Jarboe, T. R.; Gu, P.; Hamp, W.; Izzo, V.; Jewell, P.; Liptac, J.; McCollam, K. J.; Nelson, B. A.; Raman, R.; Redd, A. J.; Shumlak, U.; Sieck, P. E.; Smith, R. J.; Jain, K. K.; Nagata, M.; Uyama, T.

2000-10-01

The purpose of the Helicity Injected Torus (HIT) program is to develop current drive techniques for low-aspect-ratio toroidal plasmas. The present HIT-II spherical tokamak experiment is capable of both Coaxial Helicity Injection (CHI) and transformer action current drive. The HIT-II device itself is modestly sized (major radius R = 0.3 m, minor radius a = 0.2 m, with an on-axis magnetic field of up to Bo = 0.5 T), but has demonstrated toroidal plasma currents of up to 200 kA, using either CHI or transformer drive. An overview of ongoing research on HIT-II plasmas, including recent results, will be presented. An electron-locking model has been developed for helicity injection current drive; a description of this model will be presented, as well as comparisons to experimental results from the HIT and HIT-II devices. Empirical results from both the HIT program and past spheromak research, buttressed by theoretical developments, have led to the design of the upcoming HIT-SI (Helicity Injected Torus with Steady Inductive helicity injection) device (T.R. Jarboe, Fusion Technology 36, p. 85, 1999). HIT-SI will be able to form a high-beta spheromak, a low aspect ratio RFP or a spherical tokamak using constant inductive helicity injection. The HIT-SI design and construction progress will be presented.

Integrated Testing, Simulation and Analysis of Electric Drive Options for Medium-Duty Parcel Delivery Vehicles: Preprint

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

Ramroth, L. A.; Gonder, J.; Brooker, A.

2012-09-01

The National Renewable Energy Laboratory verified diesel-conventional and diesel-hybrid parcel delivery vehicle models to evaluate petroleum reduction and cost implications of plug-in hybrid gasoline and diesel variants. These variants are run on a field-data-derived design matrix to analyze the effects of drive cycle, distance, battery replacements, battery capacity, and motor power on fuel consumption and lifetime cost. Two cost scenarios using fuel prices corresponding to forecasted highs for 2011 and 2030 and battery costs per kilowatt-hour representing current and long-term targets compare plug-in hybrid lifetime costs with diesel conventional lifetime costs. Under a future cost scenario of $100/kWh battery energymore » and $5/gal fuel, plug-in hybrids are cost effective. Assuming a current cost of $700/kWh and $3/gal fuel, they rarely recoup the additional motor and battery cost. The results highlight the importance of understanding the application's drive cycle, daily driving distance, and kinetic intensity. For instances in the current-cost scenario where the additional plug-in hybrid cost is regained in fuel savings, the combination of kinetic intensity and daily distance travelled does not coincide with the usage patterns observed in the field data. If the usage patterns were adjusted, the hybrids could become cost effective.« less

Canadian psychiatrists' current attitudes, practices, and knowledge regarding fitness to drive in individuals with mental illness: a cross-Canada survey.

PubMed

Ménard, Ingrid; Korner-Bitensky, Nicol; Dobbs, Bonnie; Casacalenda, Nicola; Beck, Philip R; Dippsych, C M; Gélinas, Isabelle; Molnar, Frank J; Naglie, Gary

2006-11-01

To assess current attitudes, practices, and knowledge of Canadian psychiatrists regarding fitness to drive in individuals with mental illness and to explore variations according to provincial legislation. We carried out a national cross-sectional survey, using a random sample of psychiatrists. We used a mail survey to collect data. In total, 248 psychiatrists participated; the response rate was 54.2% on traced subjects. The majority (64.1%) reported that they strongly agreed or agreed that addressing patients' fitness to drive is an important issue. However, only 18.0% of respondents were always aware of whether their patients were active drivers. One-fourth strongly agreed or agreed that they were confident in their ability to evaluate fitness to drive. In discretionary provinces, 29.3% of psychiatrists reported not knowing their provincial legislation, as did 14.6% of psychiatrists in mandatory provinces; of those responding, 54.0% from discretionary provinces and 2.8% from mandatory provinces gave incorrect answers. Psychiatrists' responses demonstrate a broad range of attitudes, practices, and knowledge. There appears to be a large gap between what is expected of psychiatrists and their readiness and self-perceived ability to make informed clinical decisions related to driving safety. There is a clear need for education and guidelines to assist psychiatrists in decision making about driving fitness.

Vehicle systems design optimization study

NASA Technical Reports Server (NTRS)

Gilmour, J. L.

1980-01-01

The optimum vehicle configuration and component locations are determined for an electric drive vehicle based on using the basic structure of a current production subcompact vehicle. The optimization of an electric vehicle layout requires a weight distribution in the range of 53/47 to 62/38 in order to assure dynamic handling characteristics comparable to current internal combustion engine vehicles. Necessary modification of the base vehicle can be accomplished without major modification of the structure or running gear. As long as batteries are as heavy and require as much space as they currently do, they must be divided into two packages, one at front under the hood and a second at the rear under the cargo area, in order to achieve the desired weight distribution. The weight distribution criteria requires the placement of batteries at the front of the vehicle even when the central tunnel is used for the location of some batteries. The optimum layout has a front motor and front wheel drive. This configuration provides the optimum vehicle dynamic handling characteristics and the maximum passenger and cargo space for a given size vehicle.

Heating and current drive requirements for ideal MHD stability and ITB sustainment in ITER steady state scenarios

NASA Astrophysics Data System (ADS)

Poli, Francesca

2012-10-01

Steady state scenarios envisaged for ITER aim at optimizing the bootstrap current, while maintaining sufficient confinement and stability to provide the necessary fusion yield. Non-inductive scenarios will need to operate with Internal Transport Barriers (ITBs) in order to reach adequate fusion gain at typical currents of 9 MA. However, the large pressure gradients associated with ITBs in regions of weak or negative magnetic shear can be conducive to ideal MHD instabilities in a wide range of βN, reducing the no-wall limit. Scenarios are established as relaxed flattop states with time-dependent transport simulations with TSC [1]. Fully non-inductive configurations with current in the range of 7-10 MA and various heating mixes (NB, EC, IC and LH) have been studied against variations of the pressure profile peaking and of the Greenwald fraction. It is found that stable equilibria have qmin> 2 and moderate ITBs at 2/3 of the minor radius [2]. The ExB flow shear from toroidal plasma rotation is expected to be low in ITER, with a major role in the ITB dynamics being played by magnetic geometry. Combinations of H&CD sources that maintain reverse or weak magnetic shear profiles throughout the discharge and ρ(qmin)>=0.5 are the focus of this work. The ITER EC upper launcher, designed for NTM control, can provide enough current drive off-axis to sustain moderate ITBs at mid-radius and maintain a non-inductive current of 8-9MA and H98>=1.5 with the day one heating mix. LH heating and current drive is effective in modifying the current profile off-axis, facilitating the formation of stronger ITBs in the rampup phase, their sustainment at larger radii and larger bootstrap fraction. The implications for steady state operation and fusion performance are discussed.[4pt] [1] Jardin S.C. et al, J. Comput. Phys. 66 (1986) 481[0pt] [2] Poli F.M. et al, Nucl. Fusion 52 (2012) 063027.

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